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This is to certify that the

dissertation entitled

Experiments on the Long-term Storage of Chipping Potatoes

presented by

Robert James Fick

has been accepted towards fulfillment
of the requirements for

Ph . D . degree in Agricultural Engineering

 

 

 

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I Date 3/15/94

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EXPERIMENTS ON THE LONG-TERM
STORAGE OF CHIPPING POTATOES

By

Robert James Pick

A DISSERTATION

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Agricultural Engineering

1994

ABSTRACT
EXPERIMENTS ON THE LONG-TERM
STORAGE OF CHIPPING POTATOES

By

Robert James Fick

Tuber sugar levels were used to anticipate late storage season
sweetening. Based on biweekly sampling of stored Snowden tubers in 1992-
1993, late season rises in sucrose and glucose were detected 8 weeks and 6 to 8
weeks, respectively, before glucose levels rose above 0.01%. Samples with
0.0075°/o glucose were found to have 90% probability of having a SFA color of
S 1.5; samples with 0.01% glucose were found to have a 90% probability of
having a SFA color of s 2. Snowden tubers stored at 10.0°C sweetened and
yielded unacceptable chips at least 4 weeks before tubers stored at 72°C. Heat
treatments at 26.7°C for up to 4 weeks following harvest had a minimal effect
on the initiation date of late storage sweetening when subsequent storage was
at like temperatures, but longer treatments increased the rate at which sugars
rose.

Sampling from the top of the balanced airflow experimental storage bin
provided a representative sample of sugars and chip color for the bin. The
Snowden variety potatoes stored at 72°C responded to storage management in
a manner similar to Atlantic variety potatoes stored at 10°C for extended

storage seasons in 1990-91 and 1992-93. The Snowden variety can be cooled at

faster rates (O.3°C/ day down to 9°C) than are normally recommended for
processing potatoes in Michigan, without causing chip discoloration or rises in
sugar levels. But pile to plenum temperature differences should not exceed
2.0°C. Smaller differences (15°C) may be better if an acceptable cooling rate
can be maintained. Faster cooling rates and lower storage temperatures (7-8°C
for Snowden) can reduce the need for sprout inhibitors. Snowden potatoes
stored below 4.4°C with low temperature induced sweetening were
successfully reconditioned in the laboratory 1 of the 2 years. Reconditioning
can be successful if temperatures above 10°C are used, but storage at

temperatures below the lower limit for the variety are not recommended.

ACKNOWLEDGEMENTS

I would like to thank Dr. Roger Brook who I value as both a colleague
and a friend. I am also grateful to the members of my guidance committee,
Drs. Randy Beaudry, Jerry Cash, Philip FitzSimons and Daniel Guyer for their
suggestions and contributions.

The research was funded by a Special Grant (USDA 88-34141-3372) and
aided by the cooperation and support of the Michigan Potato Industry
Commission and Techmark Inc. Thanks also to Dennis Iott and Iott Farms,
and to Tom Bishop and Bishop Farms.

I’d like to thank my family for their encouragement and, lastly, I’d like
to thank my wife Catherine for all her support and for making the last three

years so enjoyable.

iv

TABLE OF CONTENTS

Page
List of Tables ................................................ viii
List of Figures ................................................ x
1. INTRODUCTION .......................................... 1
1.1 OBJECTIVES ........................................... 2
2. LITERATURE REVIEW ...................................... 3
2.1 STORAGE OF POTATOES ............................. 3
2.1.1 Curing period .................................... 4
2.1.2 Pre-conditioning .................................. 5
2.1.3 Cooling ......................................... 6
2.1.3 Holding ........................................ 6
2.1.4 Ventilation rate ................................... 6
2.2 SUGARS IN POTATOES .................................. 7
2.2.1 Measurement of sugars ............................. 7
2.2.2 Acceptable Sugar Levels for Chipping Potatoes .......... 7
2.2.3 Starch-sugar transformation ......................... 8
2.2.4 Low Temperature and Senescent Stress ................ 9
2.2.4.1 Key Enzymes ................................ 10

2.2.4.1.] ATP linked Phosphofructokinase (PFK) and PPi
linked Phosphofructokinase (PPi-PFK) ....... 11

2.2.4.1.2 Invertase, Sucrose 6-P synthase (SPSase),

UDPglucose pyrophosphorylase (UPPLase) . . . 11
22.4.1.3 Inorganic Phosphorus (Pi) ................ 13
2.2.4.1.4 Amyloplast Membrane ................... 14
3. MATERIALS AND METHODS ............................... 15
3.1 LATE STORAGE SEASON SWEETENING EXPERIMENT ....... 15
3.1.1 VARIETIES ..................................... 15
3.1.1.1 Potato Production ............................. 15
3.1.1.2 Collection of Potatoes .......................... 16
3.1.1.3 Washing and Sprout Inhibitor Treatment ........... 16
3.1.2 POTATO STORAGES ............................. 17
3.1.2.1 Heat Treatments and Storage Temperatures ......... 17
3.1.2.2 Humidity Control ............................. 17
3.1.2.3 Temperature Pattern for 7.2°C storage ............. 17

3.1.3.1 Chip Samples ................................ 18
3.1.3.2 Sugar Samples ............................... 18
3.2 EXPERIMENTAL STORAGES ............................. 19
3.2.1 . Storage and Ventilation System ..................... 19
3.2.2 Control System .................................. 20
3.2.3 Environmental Control ............................ 20
3.2.4 1990-1991 Storage Management ..................... 22
3.2.5 1991-1992 Storage Management ..................... 22
3.2.6 1992-1993 Storage Management ..................... 22
3.2.7 Weight Loss .................................... 26
3.2.8 Sampling ...................................... 26
3.2.9 Reconditioning .................................. 26
4. RESULTS AND DISCUSSIONS ............................... 27
4.1 CORRELATION BETWEEN CHIP COLOR AND SUGARS,
1992-1993 ............................................ 27
4.1.1 Results of Field Storage Experiments ................. 27
4.1.2 Results of Late Storage Season Sweetening Experiments . . . 31
4.1.3 Discussion of Chip Color and Sugars in Field Storage
Experiments .................................... 36
4.1.4 Discussion of Chip Color and Sugars in Late Storage
Season Sweetening Experiments ..................... 36
4.2 VARIABILITY IN SAMPLE SUGAR LEVELS FROM THE FIELD
STORAGE BINS ....................................... 37
4.2.1 T Test for Difference between Means ................. 39
4.2.2 Results of t test .................................. 42
4.2.3 Discussion of Variability in Tuber Sugar Levels in
Samples from Storage Bins ........................ 42
4.3 LATE SEASON STORAGE SWEETENING EXPERIMENT ....... 44
4.3.1 Snowden Variety Late Storage Sweetening ............. 45
4.3.1.1 Results of Snowden stored at 72°C ............... 45
4.3.1.2 Results of Snowden stored at 10°C ............... 49
4.3.1.3 Discussion Temperature Transfer ................. 53
4.3.1.4 Discussion of Snowden at 72°C .................. 55
4.3.1.5 Discussion of Snowden at 100°C ................. 56
4.3.1.6 Comparison of Late Storage Season Snowden
Sweetening at 72°C and 100°C ................... 57
4.3.2 Atlantic Variety Late Storage Sweetening ....... ' ....... 58
4.3.2.1 Results of Atlantic Stored at 100°C ................ 58
4.3.2.2 Results of Atlantic stored at 125°C ............... 59
4.3.2.3 Discussion of Atlantic at 100°C and 125°C ......... 65
4.4 FIELD STORAGE BINS .................................. 67
4.4.1 Atlantic vs Snowden in 1990-1991 Storage Season ........ 67
4.4.1.1 Results 1990-1991 ............................. 67

3.1.3 SAMPLING PROCEDURES ........................ 18

vi

4.4.1.2 Discussion 1990-1991 .......................... 67
4.4.2 Snowden Storage For 1991-1992 ..................... 67
4.4.2.1 Results of Cooling Rate Comparison ............... 67
4.4.2.2 Discussion of Cooling Rates ..................... 68
4.4.2.3 Results of Sprout Control ....................... 68
4.4.2.4 Discussion of Sprout Control .................... 68
4.4.2.5 Results of Reconditioning ....................... 69
4.4.2.6 Discussion of Reconditioning .................... 69
4.4.2.7 Discussion of Bin Exhaust Problems ............... 69
4.4.3 Snowden Storage for 1992-1993 ...................... 72
4.4.3.1 Results of Cooling Rates and Storage Temperatures . . . 72
4.4.3.2 Discussion of 1992-1993 Cooling Rates and Storage
Temperatures ................................ 74
4.4.3.3 Results for Reconditioning ...................... 74
4.4.3.4 Discussion of Reconditioning .................... 75
4.4.3.5 Results of Weight Loss in Storage ................. 75
4.4.3.6 Discussion of Weight Loss in Storage .............. 75
4.4.3.7 Result for Sprout Growth ....................... 75
4.4.3.8 Discussion of Sprout Growth .................... 75
5. CONCLUSIONS .......................................... 76
6. RECOMMENDATIONS FOR THE STORAGE OF SNOWDEN ....... 78
7. SUGGESTIONS FOR FUTURE WORK ......................... 79
8. REFERENCES ............................................ 80
APPENDICES
APPENDIX A Sugar and temperature for research bins for 1990-1991
season. ..................................... 84
APPENDIX B Sugar, temperature and agtron color for research bins,
1991-1992. ................................... 88
APPENDD< C Equations for Figure 4.2 (acceptable samples versus
glucose level). ................................ 92
APPENDIX D T test for the difference between means of samples at
0.6, 1.7, 3.0 and 4.3 m above the floor in the three
research bins for the 1992—1993 storage season, Snowden
variety. ..................................... 95
D.1 Paired t test for all data ........................... 96

vii

D.2 Paired t test for trimmed data ...................... 108

APPENDIX E Curves of late storage season sweetening, 1992-1993. . 120

viii

TABLE 1.1
TABLE 3.1
TABLE 3.2
TABLE 3.3

TABLE 4.1

TABLE 4.2a

TABLE 4.2b

TABLE 4.3

TABLE 4.4

TABLE 4.5a

TABLE 4.5b

TABLE A.1

LIST OF TABLES

Page
Utilization of potatoes consumed in the USA in 1992 ...... 1
Storage Dates and Parameters, 1990-1991 .............. 23
Storage Dates and Parameters, 1991-1992 .............. 24
Storage Dates and Parameters, 1992-1993 .............. 25

Glucose (°/o)', Sucrose (°/o)' and Color (SFA)" for Snowden in
Field Storage Bins. 1992-1993. ...................... 28

Glucose (°/o)°, Sucrose (°/o)' and Color (SFA)" for Snowden
variety in Late Storage Season Sweetening Experiment.
1992-1993. ...................................... 29

Glucose (°/o)', Sucrose (°/o)' and Color (SFA)" for Atlantic
variety in Late Storage Season Sweetening Experiment.
1992-1993. ...................................... 30

Snowden sugar levels (°/o)' for all samples from field storage
bins grouped by color (SFA)”, 1992-1993. .............. 32

Sugar levels (°/o)' for all samples from the late storage
season sweetening experiment grouped by color (SFA)",

1992-1993. ...................................... 35
Summary of paired t test for differences between means.
ALL DATA. .................................... 41
Summary of paired t test for differences between means.
TRIMMED DATA. ............................... 41
Potato sugar and temperature data for 1990-1991 ......... 84

ix

TABLE B.la

TABLE B.1b

TABLE B.1C

TABLE C .1

TABLE E.1

Potato sugar and temperature data for bin 1, 1991-1992. . . . 89

Potato sugar and temperature data for bin 2, 1991-1992. . . . 90
Potato sugar and temperature data for bin 3, 1991-1992. . . . 91
Acceptable chips and glucose levels for intervals,

1992-93. ....................................... 92
Coefficients for sweetening curves, 1993. ............. 120

Fig. 2.1

Fig. 3.1

Fig. 4.1

Fig. 4.2

Fig. 4.3

Fig. 4.4

Fig. 4.5a

Fig. 4.5b

LIST OF FIGURES

Page

A theoretical scheme for the partitioning of carbons in potatoes.
Enzymes represented are: (1)UDPglucose pyrophosphorylase,

(2) sucrose 6-P synthase, (3) sucrose 6-P phosphatase, (4)

alkaline invertase, (5) acid invertase, (6) phosphoglucomutase,
(7) phosphohexose isomerase, (8) fructose 6—P,2-kinase, (9)
fructose 2,6-bisphosphatase, (10) PPi linked phosphofructokinase,
(11) ATP linked phosphofructokinase, (12) fructose 1,6-
bisphosphatase, (13) triose-P, Pi translocator protein, (14)
ADPglucose pyrophosphorylase, (15) starch synthase, (16) on-
glucose phosphorylase, (17) pyruvate kinase and (18) hexose-P,
Pi translocator protein. From Sowokinos (1990). ........... 12

Ventilation system and sensor placement within the potato bin. 21

Color (SFA") versus glucose' and average glucose' for samples in
1992-1993. ' °/o fresh weight basis. " Snackfood Association. . . 33

Probability of SFA color for levels of glucose in chip samples for
the 1992-1993 storage season (research bins) ................ 34

Bin temperature and glucose levels at 0.6, 1.7, 3.0 and 4.3 m
(top) above bin floor. Note: Glucose scale is different for
bin 3. ............................................ 38

Bin temperature and sucrose levels at 0.6, 1.7, 3.0 and 4.3 m
(top) above bin floor. ................................ 40

Sugar levels for Snowden variety with no heat treatment and
72°C holding temperature. ............................ 46

Sugar levels for Snowden variety with 1 week heat treatment at
267°C and 72°C holding temperature. ................... 46

xi

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

4.5c

4.5d

4.6a

4.6b

4.7a

4.7b

4.7c

4.7d

4.8a

4.8b

4.9a

4.9b

4.9c

4.9d

4.10a

Sugar levels for Snowden variety with 2 week heat treatment
at 267°C and 72°C holding temperature. ................. 47

Sugar levels for Snowden variety with 4 week heat treatment
at 267°C and 72°C holding temperature. ................. 47

Glucose late storage season sweetening for Snowden variety
stored at 72°C. (183°C after 3/ 16/93). ................... 50

Sucrose late storage season sweetening for Snowden variety
stored at 72°C. (183°C after 3/ 16/ 93). ................... 50

Sugar levels for Snowden variety with no heat treatment and
100°C holding temperature. ........................... 51

Sugar levels for Snowden variety with 1 week heat treatment
at 267°C and 100°C holding temperature. ................ 51

Sugar levels for Snowden variety with 2 week heat treatment
at 267°C and 100°C holding temperature. ................ 52

Sugar levels for Snowden variety with 4 week heat treatment
at 267°C and 100°C holding temperature. ................ 52

Glucose late storage season sweetening for Snowden variety
stored at 100°C. .................................... 54

Sucrose late storage season sweetening for Snowden variety
stored at 100°C. .................................... 54

Sugar levels for Atlantic variety with no heat treatment and
100°C holding temperature. ........................... 60

Sugar levels for Atlantic variety with 1 week heat treatment
at 267°C and 100°C holding temperature. ................ 60

Sugar levels for Atlantic variety with 2 week heat treatment
at 267°C and 100°C holding temperature. ................ 61

Sugar levels for Atlantic variety with 4 week heat treatment
at 267°C and 100°C holding temperature. ................ 61

Glucose late storage season sweetening for Atlantic variety
stored at 100°C. .................................... 62

xii

Fig. 4.10b

Fig. 4.11a

Fig. 4.11b

Fig. 4.11c

Fig. 4.11d

Fig. 4.12a

Fig. 4.12b

Fig. 4.13

Fig. 4.14

Fig. 4.15a

Fig. 4.15b

Fig. 4.16

Sucrose late storage season sweetening for Atlantic variety
stored at 100°C. .................................... 62

Sugar levels for Atlantic variety with no heat treatment and
125°C holding temperature. ........................... 63

Sugar levels for Atlantic variety with 1 week heat treatment
at 267°C and 125°C holding temperature. ................ 63

Sugar levels for Atlantic variety with 2 week heat treatment
at 267°C and 125°C holding temperature. ................ 64

Sugar levels for Atlantic variety with 4 week heat treatment
at 267°C and 125°C holding temperature. ................ 64

Glucose late storage season sweetening for Atlantic variety
stored at 125°C. .................................... 66

Sucrose late storage season sweetening for Atlantic variety
stored at 125°C. .................................... 66

Sprout control for samples of 60 tubers, 15 at each level,
1991-1992. Bin 1 was treated with sprout inhibitor on
1 1 / 20 / 91. ......................................... 70

Color (SFA) of reconditioned potatoes. 1992. Reconditioned
at 8.3, 11.7, 155°C and at 1 week steps of 8.3, 11.7 and

155°C ............................................. 70
Bin temperature and sugars for bin 1, 1991-1992. ........... 71
Bin temperature and sugars for bin 2, 1991-1992. ........... 71

Temperatures and sugar levels for field research bins. Note:
change in scale and sucrose units for bin 3. 1992-1993. ...... 73

xiii

1. INTRODUCTION

Potatoes are harvested throughout the year in the United States. Of the
potatoes grown in 1992, about 89% were harvested in the fall (National Potato
Council, 1993). Storage is required to maintain a uniform supply of potatoes
throughout the year.

The environment required in the storage will depend on the manner in
which the potatoes are to be utilized. Potato utilization in the United States is

outlined in Table 1.1.

 

TABLE 1.1 Utilization of potatoes consumed in the USA in 1992.’

FRESH 38.0%
PROCESSED
Frozen 37.8%
Chips (and shoestrings) 12.7%
Dehydrated 10.1%
Canned 1 .40/0

'From National Potato Council’s 1993 Potato Statistical Yearbook.

 

When potatoes are to be used for chipping their suitability for
processing into chips is dependent on sugar content in addition to internal and
external defects. The susceptibility of potatoes to low temperature sweetening
and stress related sweetening necessitate a more complete understanding of
potato physiology.

Physiological aging of tubers, which will vary by growing conditions as

well as by storage conditions, may affect the suitability of tubers for long term

2

storage. A study was conducted on the response of tubers of differing
physiological ages could be determined during long-term storage.

In 1992 a Bin Monitoring Program was initiated by the Michigan Potato
Industry Commission to aid growers in the evaluation of the storage potential
and in the marketing of their potatoes. Much of the background information
for this program was obtained in the Michigan State field research bins. The
monitoring and control provided by these bins can provide an important tool
in determining the variability that can be expected within a bin and also

provide a scientific method to test changes in storage procedures.

OBJECTIVES
- To develop guidelines for the critical sugar levels and the significance of
changes in sugars levels of physiologically aged potatoes
- To monitor the effects of cooling rate and low temperature storage limits on
the long term storability of chipping potatoes.

- To develop guidelines for the long term storage of Snowden potatoes

2. LITERATURE REVIEW
2.1 STORAGE OF POTATOES

In thestorage of potatoes, it is critical to recognize that the potato is a
living organism and the proper environment is needed to protect this
perishable product. Improper storage has been estimated to cause a loss of
nearly one-third of the potato crop harvested in many countries (Niederhauser,
1993).

Storage losses are normally designated as losses of either weight or
quality. The three elements controlled in a potato storage are the temperature,
humidity, and oxygen availability. If any of these elements are neglected,
product quality can suffer. A good storage can limit storage losses in a good
product, but nothing can be done to improve a poor product. It is therefore
necessary to assure the quality and maturity of potatoes going into storage.

The market for the stored potatoes will also affect the choice of storage
conditions. The principal markets for potatoes in Michigan are seed, table
stock, and processing. Storage conditions are most restrictive for processing
potatoes where a very low and uniform content of reducing sugars is required
(Burton et al., 1992). Prolonged exposure to low temperatures and stress (e.g.
handling, rapid temperature change, oxygen depletion) can cause starch
conversion to sugars and will cause dark colored processed products (a result
of a Maillard reaction between the reducing sugars and amino acids in the
potatoes).

The following storage procedures are used for mature chipping potatoes

4

grown without excessive stress, and harvested under conditions that will not
alter the normal biological processes in the potato tuber.
2.1.1 Curing period

Following harvest, a period of time is required for temperature
equilibration and wound healing. The optimal harvest conditions for potatoes
are temperatures of 10-18°C and soil moisture availability of 60-65% (Plissey,
1993). When the tubers are placed in the storage, temperatures of different
tubers may vary 5°C or more. Up to a week may be required for equalization
of the temperatures and drying of the tubers.

After harvest, a suberization or wound healing phase starts. This phase
allows recovery from the shock of harvesting and handling and formation of
new skin on damaged areas.

Ventilation is essential during the curing period. Air movement and
exchange are necessary in controlling temperature, moisture, and the exchange
of oxygen and carbon dioxide. Recommendations on fan operation have
suggested minimum levels of eight hours a day in two intervals (Cargill et al.,
1989), and evening only operation (Schaper and Preston, 1989). Mazza and
Siemens (1990) measured the C02, sugars, and chip color in commercial
storages and found the highest CO2 levels during suberization. Increases in
sugar levels generally occurred immediately after rises in carbon dioxide
levels.

From conversations with growers across Michigan, it is apparent that

during curing, most managers of chip storages in Michigan run fans

5

continuously with pile air temperatures held between 125°C and 16°C
depending on variety and tuber temperature at harvest. A tuber which is in
thermal equilibrium with its surroundings will have a slightly elevated
temperature due to metabolic heat production. Burton et al. (1992) estimated a
temperature gradient of 02°C from the center of a tuber to the periphery. This
was calculated using an approximate specific heat of the tissue of 3.6 1°C" g“
and a typical heat production of 50 mI-g'l-h“.

Ventilation rates of at least 56 m3't'1-hr'1 are recommended for chip
potato stores in Michigan (Forbush and Brook, 1993). Some fresh air should be
provided regularly to prevent the build up of carbon dioxide and the depletion
of oxygen which can be detrimental to potatoes (ASAE EP475 4.3, 1993). A
level of 1.0% carbon dioxide should be considered the upper limit with a
common level in ventilated bins of 0.2 to 0.3%.

2.1.2 Pre-conditioning

Pre-conditioning is an extension of suberization where the reducing and
non-reducing sugars are respired or ”burned off". The storage environment is
maintained similar to suberization with temperatures around 16°C. The
preconditioning treatment has been adapted due to unpredictability in the
reconditioning of potatoes (Schaper and Preston, 1989). Reconditioning is the
practice of warming the potatoes from the holding temperature to obtain
desirable processing color.

The duration of the pre-conditioning treatment is dependent on the chip

color and sugar content. Some potatoes may not need pre-conditioning while

6

others may never attain desired levels. This treatment is completed when
chips from the potatoes have reached an acceptable sugar level, usually judged
by chip color.

2.1.3 Cooling

After the potatoes have reached acceptable sugar levels and chip color,
cooling should be initiated. Potato storage ventilation systems in Michigan are
designed to mix fresh air with recirculated air to cool the storage. Ambient
conditions determine how rapidly cooling can take place. Advances in control
systems allow precise metering of fresh air with recirculated air, eliminating
much of the guesswork in ventilation cooling systems.

For processing potatoes, Cargill et al. (1989) recommended a maximum
rate of 3°C per week. Another common practice recommended by Thornton
(1989) is cooling as quickly as possible to a holding temperature of 10°C.

2.1.3 Holding

Once the potatoes have reached the desired holding temperature, the
ventilation rate can be reduced if desired. Temperature uniformity is very
important to maintain the required process color for long term storage of
potatoes, especially as the pile approaches the lower limit for the variety.

2.1.4 Ventilation rate

The influence of airflow rate on chip potato storage management was
investigated by Forbush and Brook (1993). All rates achieved the required
temperature and humidity control. Although lower ventilation rates are used

in other parts of the country, a ventilation rate of 56 m3't'1-hr'1 is still

7

recommended for chip potato storage in Michigan, particularly to be able to
deal with potatoes harvested during a wet fall.
2.2 SUGARS IN POTATOES

The balance between starch and sugar is maintained in the potato as it
grows. As the tuber matures, the sucrose levels decrease (Iritani and Weller,
1977) and reducing sugars drop to levels that are acceptable for processing and
storage. Sowokinos (1978) modeled the relationship of harvest sucrose content
to processing maturity and storage life of potatoes. He found that a low
sucrose rating at harvest was a good indicator of storability for chipping.
2.2.1 Measurement of sugars

The levels of reducing sugars, and more specifically glucose, are often
used as a quantitative indicator of acceptability of potatoes for chipping.
Leszkowiat et al. (1990) suggested that only part of the chip color could be
accounted for by the reducing sugars and that part of the variation in color
was due to the sucrose. But under usual storage conditions the glucose levels
correlate very well with the chip color.
2.2.2 Acceptable Sugar Levels for Chipping Potatoes

Mazza et al. (1983) demonstrated that reducing sugars, tuber
temperature, and sucrose were important in determining chip color of stored
tubers. The relative importance of each parameter varied with the age of the
tubers, year in which the potatoes were grown and stored, and cultivar. He
concluded that the quantitative relationship between the factors assayed was

not sufficiently stable to serve as a general measure of prediction.

8

Santerre et.al. (1986) determined that sucrose levels were useful in the
determination of tuber maturity. A sucrose rating (mg sucrose/ g fresh tuber)
of 1 was used to determine maturity of varieties for processing. Sowokinos
and Preston (1988) developed procedures for monitoring chemical maturity of
potatoes on the basis of sugar content. For the cultivar Norchip, they
recommended harvest sugar levels of less that 0.1% (fresh weight basis) for
sucrose and less than 0.035% for glucose. They suggested that other
processing cultivars should experience safe levels close to those observed for
Norchip.

Though chip color is the true test of the marketability of potatoes,
comparisons of chip color are much more difficult to quantify than sugars.
Even when differentiation can be made using an Agtron colorimeter,
repeatability of a given sample of chips is dependent on chip placement and
variation in the sample. Orr (1990) compared two Agtrons, using crushed and
whole chips and discussed their application. He concluded that whenever
color comparisons of processed potato products are being made, any change in
instrumentation or analysis procedures requires a correlation check if data are
to be interchanged.

2.2.3 Starch-sugar transformation

The transformation of starches to sugars in storage is variety-dependent
and is also influenced by stress during growth, maturity at harvest, and
storage environment. The pathways leading to stress-induced sweetening are

still unexplained at the molecular level as many factors act in regulating sugar

9

synthesis and degradation in potatoes. The temperature and intactness of the
cell structure are both important in the formation of sugars, along with the key
enzymes discussed below.

2.2.4 Low Temperature and Senescent Stress

Lowering the temperature slows most biological reactions including
respiration and this is the basis for low temperature storage. Shekhar and
Iritani (1978) found evidence of physical changes in the membranes of potato
tubers that had accumulated sugars at low temperatures. Potatoes are not
considered chill sensitive in the classical sense as the process is reversible. The
sensitivity of potato tubers to low temperatures is mainly concerned with the
transformation of starch to sugars.

Burton (1974) found a temperature coefficient (Q10) for potato respiration
of 1.2-1.3 in the temperature range of 10-20°C. The minimum respiration rate
for Russet Burbanks was found to occur around 7°C (Boe, 1974). Hunter (1986)
determined that a respiration rate of 4 mg'kg'1 -hr'1 of carbon dioxide at time
of harvest indicates relatively mature tubers. He also found a minimum
respiration rate at 72°C.

Barichello et al. (1990a) demonstrated that the cold sweetening resistant
ND 860-2 showed a higher respiration rate than the cold-sensitive Norchip.
Similar results were found by Ehlenfeld et a1. (1990). Both agreed that the
trend of higher respiration in ’cold-chippers’ may contribute to their low sugar
accumulation primarily through variations in the enzyme activity of

phosphofructokinase (discussed in section 2.2.4.1.1).

10

Senescence in potato tubers has most often been studied when the
tubers are intended for seed. Reust and Aerny (1985) used the physiological
age of tubers as determined by sucrose, citric acid and malic acid as indicators
of senescence. Sucrose rose quickly as sprouting occurred. van Ittersum et al.
(1990) developed a method to assess cultivar differences in rate of
physiological aging of seed tubers using measurements of sprout weight,
number of sprouts and growth vigor.

Isherwood and Burton (1975) found sugar accumulation occurred in
senescent tubers at 20°C even in the absence of wilting (of the tubers) and
particularly if sprout growth was prevented chemically or the spouts removed.
Hughes (1984) measured sugars in the cultivar Record, stored at 10°C and
attributed rises in sugars at 320 days to senescence.

The concept of measuring the physiological age for seed tubers as the
number of day-degrees above a base temperature from the onset of sprouting
to planting is quantitative and practical (Allen et al., 1992). The base
temperature is 4°C and lower depending on the variety. How this could be
applied to chipping tubers is unknown.
2.2.4.1 Key Enzymes

To better understand how stresses affect sweetening in potatoes,
Sowokinos (1990) developed a theoretical scheme for the partitioning of carbon
in potatoes (Figure 2.1). The ability of stress to cause sugar accumulation is
likely due to a shift or variation in the balance between starch synthesis and

degradation, respiration, sucrose formation and sucrose hydrolysis.

ll

 

srARCH
GRANULE,W

   
  

CYTO PLASM ATP H20 + co2

/
(GLYCOLYSIS) I7 PYR ——’ (Mv RESPIRATION)

 

 

ATP
”PEP ADP

   
  
   

 

I
{span sect? “09+“ 02
' “‘1’?
I s.
STARCH I \FLGPZ
i to p' ADP H20
6" pp. "- up P. 8'2
. F p F
7/ 6 ‘—s— 2'6”
6 GGP
ADPG We”: mp 53/
p. m: Pi 2 sucnose-e-p

UT? 3 pg

1, \
\
Amy‘omt\ 99' UDP GLUCOSE SUCROSE
Membrane , /
(GLUCONEOGENESIS) /<
GLUCOSE

FRUCTOSE

  
  
          

Tonoplost p' SUCROSE

  

GLUCOSE

VACUOLE 5 muc rose

     

 

Fig. 2.1

A theoretical scheme for the partitioning of carbons in potatoes.
Enzymes represented are: (1)UDPglucose pyrophosphorylase, (2)
sucrose 6-P synthase, (3) sucrose 6-P phosphatase, (4) alkaline
invertase, (5) acid invertase, (6) phosphoglucomutase, (7)
phosphohexose isomerase, (8) fructose 6-P,2-kinase, (9) fructose
2,6-bisphosphatase, (10) PPi linked phosphofructokinase, (11) ATP
linked phosphofructokinase, (12) fructose 1,6-bisphosphatase, (13)
triose-P, Pi translocator protein, (14) ADPglucose
pyrophosphorylase, (15) starch synthase, (16) a—glucose
phosphorylase, (17) pyruvate kinase and (18) hexose-P, Pi
translocator protein. From Sowokinos (1990).

 

12
2.2.4.1.1 ATP-linked Phosphofructokinase (PFK) and PPi-linked

Phosphofructokinase (PFP)

Glycolysis may be restricted at low temperatures by the activity of PPi-
PFK and ATP-PFK (Figure 2.1, rx 10 and 11). Sinha et al.(1990) found a
negative correlation between PFP and sugar accumulation in stored tubers, i.e.
a high PPi-PFK activity is associated with low glucose content and vice-versa.
Claassen et al. (1991) suggested that PFP activity contributes to the cold
induced accumulation of sugars by controlling PPi concentration, thus
facilitating UDP-Glu and sucrose synthesis.
2.2.4.1.2 Invertase, Sucrose 6-P synthase (SPSase), UDPglucose
pyrophosphorylase (UPPLase)

The enzymes invertase, Sucrose 6-P synthase and UDPglucose
pyrophosphorylase are believed to be critical in influencing sugar formation in
gluconeogenesis (Figure 2.1, rx 1, 2, and 4).

The presence of invertase and an invertase inhibitor has been reported
in potato tubers (Schwimmer et al., 1961) and confirmed by others. When
tubers are held at low temperatures, invertase activity is increased and there is
a reduction in inhibitor activity (Pressey, 1969). Ross et al. (1992) concluded
that acid invertase in the vacuole or at the tonoplast was more likely than
SPSase to regulate sugar accumulation in stored tubers.

SPSase has been cited as demonstrating several characteristics of a
regulator enzyme (Dwelle, 1990). The activity of SPSase has been shown to

track the increases in sugars at low temperatures (Pressey, 1970; Pollock and

13

ap Rees, 1975). Sowokinos (1990) reported a greater increase in the specific
activity of SPSase in varieties sensitive to low temperature sweetening than
varieties less sensitive to low temperatures.

Murata (1972) found that for SPSase to reach 50% of its catalytic activity,
high concentrations of UDPglucose (Km =25 mM) are required. The level
found in potato tubers is 10-20 times lower (Morrell and ap Rees, 1986). This
would indicate that the UDPglucose supplied by reaction 1 in Figure 2.1 would
be rate limiting. Sowokinos (1990) found the UPPLase activity versus glucose
to be highly correlated over long term storage at 3°C and with the varietal
activity being the highest in the highest sugar clones.
2.2.4.1.3 Inorganic Phosphorus (Pi)

The location of inorganic phosphorus or compartmentation of the cell is
also believed to play a role in starch to sugar conversion (Isherwood, 1976).
Shehkar and Iritani (1978) found a positive correlation between the Pi and
reducing sugar concentration. The largest concentration of Pi is in the vacuole
and leakiness of the tonoplast during cold stress could be responsible for
elevating the level of Pi in the cytoplasm.

Excess Pi would aid the mobilization of carbon from the amyloplast to
the cytoplasm and would also serve as an inhibitor of ADPglucose
pyrophosphorylase (Sowokinos and Preiss, 1982). Senescence stress has also
been suggested in increased permeability of the tonoplast by Sowokinos (1990).
2.2.4.1.4 Amyloplast Membrane

Sowokinos et.al. (1987) found that senescence in Norchip potatoes

14

occurred after 8 to 10 months of storage at 10°C. Once senescence initiated
gross physical changes in the integrity of the amyloplast membrane, handling
stress was accented. Lulai et al. (1986) looked at a physiological defect that
involved translucent-like tissue which occurred randomly in Kennebec potato
tubers after 8 months storage. The defect appeared to be an exaggerated form
of senescence in the amyloplast membrane.

Barichello et al. (1990b) used chill sensitive Norchip and chill
sweetening resistant ND 860-2 varieties to compare the starch granule
composition over storage time. ND 860-2 had higher amylose and lower
amylopectin as well as a higher crystallinity as compared to starch isolated
from Norchip potatoes. Data suggest that starch granule composition is a
factor differentiating the low-temperature sweetening sensitive cultivar from

the resistant potato cultivar.

3. MATERIALS AND METHODS

3.1 LATE STORAGE SEASON SWEETENING EXPERIMENT

Late in the 1991-1992 storage season, potatoes from many storages in
Michigan produced dark chips when exposed to small temperature changes or
for no apparent reason at all. Reconditioning (warming the potatoes) was
often unsuccessful in removing sugars and the physiological age of the tubers
(resulting from a warm growing season) was cited as a probable contributing
factor (personal contacts with growers and potato researchers at Michigan State
University). A laboratory experiment was performed during the 1992-1993
storage season to:

1. To determine the rate of aging when potato tubers are held at a high

temperature, 267°C, as determined by increases in sugar content and

changes in chip color.

2. To estimate the rates of sugar accumulation in physiologically aged

tubers and develop guidelines to address the sequence of sugar changes.
3.1.1 VARIETIES

The two potato varieties used in this experiment were the Snowden and
the Atlantic. Both varieties are high yielding, round whites that are commonly
stored in Michigan. The Snowden is a more recently developed variety that
has become the most common long-term storage chipping potato in Michigan.
3.1.1.1 Potato Production

The potatoes used in this experiment were grown on irrigated clay soil

at Bishop Farms in Bay County, Michigan. The fields were sprayed with

15

16

maleic hydrazide (MH30), a sprout suppressant, in mid-August. Diquat was
used for vine kill 10 to 20 days before harvest.
3.1.1.2 Collection of Potatoes

The Snowden potatoes were harvested the morning of October 6 at a
pulp temperature of approximately 15°C. The Atlantic potatoes were
harvested the morning of October 7 at a pulp temperature of about 14°C. Both
varieties were dug with a conventional harvester and were handled the same
as potatoes entering commercial storage. Tubers for the experiment were
collected from the sorting line and placed in mesh sacks at a point where they
were leaving a fluidized sand bed sorter to be conveyed into the storage. The
Snowden tubers were stored overnight in the MSU Agricultural Engineering
Building at about 155°C.
3.1.1.3 Washing and Sprout Inhibitor Treatment

On October 7 the potatoes were transported to the MSU Montcalm
research station, run through an automatic washer and dipped in a solution of
Sprout Nip, which contains the sprout inhibitor isopropyl N-
chlorphenylcarbamate (CIPC). The solution was mixed at the concentration
recommended for spray treatment of tubers. This is standard procedure for
research potatoes at MSU‘. The tubers were then air dried and transported
back to the Michigan State campus and held in a cooler at 155°C (599°C) until

October 8.

 

1Personal communication with Dick Chase, MSU Extension Potato
Agronomist.

17
3.1.2 POTATO STORAGES

On October 8 the tubers were randomly divided into treatment groups.
The tubers were placed in perforated stackable boxes of dimensions 41 x 51 x
15 cm (16 x 20 x 6 in.).
3.1.2.1 Heat Treatments and Storage Temperatures

Tubers of different physiological ages were created by placing the
harvested tubers in storage at 267°C (80°F) for periods of 0, 1, 2 and 4 weeks.
During heat treatments, tubers were inspected every other day. Rotted tubers
were removed to prevent the rotting of other tubers. After the heat treatment,
the tubers were transferred to coolers at 155°C for two weeks (suberization),
and then to the final storage temperatures.

The Snowden potatoes had final storage temperatures of 7.2 and 100°C
(45.0 and 50.0°F), and the Atlantic potatoes had final storage temperatures of
10.0 and 125°C (50.0 and 54.5°F).
3.1.2.2 Humidity Control

The relative humidity of the heat treatment room, the suberization
room, and the 7.2°C storage were held above 90%. The 10.0 and 125°C.
storages were held above 80% but could not be held higher due to limitations
of the temperature control systems.
3.1.2.3 Temperature Pattern for 7.2°C Storage

The storage holding the Snowden tubers at 72°C was gradually and
inadvertently warmed from 72°C on March 1 to 183°C (65.0°F) on March 21.

The temperature remained at 183°C until the end of the experiment.

18
3.1.3 SAMPLING PROCEDURES

3.1.3.1 Chip Samples

Samples of eight tubers were taken for chipping and sugar analysis biweekly
or when a temperature transfer occurred. The eight unpeeled tubers were
sliced lengthwise through the stem. Three slices of thickness 1.5 mm (0.060
inches) were taken from each tuber and were placed in cold tap water while
the remainder of the potato was prepared for the sugar sample. The slices
were left in the cold water for at least 0.5 minutes and up to 5 minutes with
the norm being about 1.5 minutes. The soaking in water rinsed the slices and
also allowed easier separation in the fryer.

The slices were drained and fried in soybean oil at 182°C (360°F). The
fry time was approximately 115 seconds as recommended by Gould (1989), or
until all the water had been cooked out (ie, only a few bubbles rising).2

The chip samples were then visually scored using the Snackfood
Association’s 1 to 5 color chart using 0.5 steps (Snackfood Association,
undated).
3.1.3.2 Sugar Samples

The sugar analysis followed closely the procedure of Sowokinos and
Preston (1988). 200 grams of the potato centers were juiced into pint plastic
fruit jars. Three portions of cold (4°C) distilled water were used to wash the

sample to a total volume of 430 ml. The juice in the plastic jar was then

 

2The fry time is dependent on the specific gravity of the potato, the oil
temperature, the slice thickness, and the degree of separation of the slices as they
enter the oil.

19

refrigerated for one hour and a 10 ml sample placed in a 30 m1 plastic blood
sample vial and frozen on dry ice for later analysis.

Every 2 or 4 weeks the frozen samples were thawed to room
temperature and a Yellow Springs Instruments (YSI) model 2700 sugar
analyzer was used to determine the glucose and sucrose concentrations.

3.2 EXPERIMENTAL STORAGES

The MSU research bins are operated in conjunction with the Storage and
Handling Committee of the Michigan Potato Industry Commission. The
objectives of the research bins for the years 1990-1993 were:

1. To compare the storage recommendations for Atlantic and Snowden

potatoes.

2. To determine the variability in tuber sugar levels that can be expected

in a potato storage.

3. To determine the critical sugar levels in the storage of Snowden

potatoes.

4. To monitor the effects of varying cooling rates and lower temperature

storage limits.

3.2.1 Storage and Ventilation System

The MSU storage is a set of three bins, each measuring 2.44 x 2.44 x 5.50
m (8' x 8’ x 18’) high. Two of the bins were located in a commercial potato
facility at Bishop Potato Farm (Pinconning, MI) and the third in a commercial
potato facility at Iott Farm (Kalkaska, MI).

Each potato storage research bin had an independent air handling

20

system capable of maintaining a desired storage environment for that bin.
3.2.2 Control System

Each ventilation system was controlled using a 656 Fancom3
environmental control computer. The computer controls fresh air and
recirculation air volume and humidifying and heating devices. Control
changes are made based on feedback from the sensors that are placed in the
ventilation system and in the pile as illustrated in Figure 3.1:

- temperature sensors at one meter increments within the pile

° temperature and relative humidity of ventilation air

- temperature and relative humidity of recirculation air

° temperature of fresh air
3.2.3 Environmental Control

The controller was set to maintain the difference between any two pile
temperature sensors at less that 0.2°C (0.36°F) and the difference between the

plenum and the pile average at no more that 2°C (38°F).

 

3Trade names are used solely to provide specific information. Mention of
a trade name does not constitute a warranty of the product by the authors or by
Michigan State University or an endorsement of the product to the exclusion of
other products not mentioned.

21

 

WWII

/.

thxxxxxxx.

|\\\\\\
\\\\ \-

 

 

 

 

 

 

 

 

 

 

k) HALF-HINGE?

 

Egg

CONERCIAL
STGQAGE
BIN

 

Figure 3.1. Ventilation system and sensor placement within the potato bin.

22

Dates, temperatures and ventilation information are presented in Table
3.1 for the 1990-1991 season, Table 3.2 for the 1991-1992 season, and Table 3.3
for the 1992-1993 season.

3.2.4 1990-1991 Storage Management - Snowden and Atlantic potatoes were
stored for an extended season and their response monitored for the storage
strategies used in previous research on Atlantic potatoes. The Atlantic
potatoes were held at 10°C (50°F) and the Snowden potatoes were held at 72°C
(45°F). Other storage procedures are listed in Table 3.1.

3.2.5 1991-1992 Storage Management

After the storages were filled and the tubers suberized, the bins were
cooled at the rates listed in Table 3.2. Bin 1 was cooled at a rate commonly
used in commercial storages and was treated with sprout inhibitor on
November 20, 1991. Bins 2 and 3 were cooled at faster rates and were not
treated with sprout inhibitor.

On approximately January 18, 1991 the exhaust louver for the building
enclosing Bins 1 and 2 malfunctioned and the experiment was terminated.
3.2.6 1992-1993 Storage Management

The bins were cooled to the temperatures and at the rates listed in Table
3.3. Bin 1 was stored at 72°C and bin 3 was stored at 44°C. Bin 2 was cooled
until color developed in chips and then the temperature was increased to hold
at 70°C. Some warming of bins 1 and 2 was done in March for reconditioning

of the potatoes.

23

TABLE 3.1a Storage Dates and Parameters (Metric Units)

 

1990-1991

 

Harvest date

Harvest temperature
Suberization run time
Cooling run times

Ventilation rate
Slot velocity
Desired R. H.

CIPC Application

Set cooling rate (actual)

Start holding

Holding run times
Holding temperature

BIN 1 (Atlantic) BIN 2 (Snowden)
Sep. 26, 1990 Sep. 26, 1990
19.4°C 139°C

24 hours 24 hours

6/ 12 hours 6 / 12 hours

82.1 m3/t 104.5 m3/t

360 m/rnin 427 m/ min

90% 90%

Start Cooling/ End Precond. Oct. 31, 1990 Oct. 31, 1990
Nov. 12, 1990 Nov. 12, 1990
0.1°C / day(0.08) 0.1°C /day(0.10)
Jan. 8, 1991 Jan. 22, 1991
3/ 12 hours 3/ 12 hours
10°C 72°C
Apr. 9, 1991 Apr. 91 1991

Market date

 

TABLE 3.1b Storage Dates and Parameters (English Units)

 

 

 

 

1990-1991 BIN 1 (Atlantic) BIN 2 (Snowden)
Harvest date Sep. 26, 1990 Sep. 26, 1990
Harvest temperature 67°F 57°F
Suberization run time 24 hours 24 hours
Cooling run times 6/ 12 hours 6/ 12 hours
Ventilation rate 2.2 cfm/cwt 2.8 cfm/cwt
Slot velocity 1180 ft/ min 1400 ft/ min
Desired R. H. 90% 90%

Start Cooling/ End Precond. Oct. 31, 1990 Oct. 31, 1990
CIPC Application Nov. 12, 1990 Nov. 12, 1990
Set cooling rate (actual) 0.18°F/day(0.15) 0.18°F/day(0.18)
Start holding Jan. 8, 1991 Ian. 22, 1991
Holding run times 3/ 12 hours 3/ 12 hours
Holding temperature 50°F 45°F

Market date Apr. 9, 1991 Apr. 9, 1991

 

24

TABLE 3.2a_ Storage Dates and Parameters (Metric Units)

 

 

 

 

 

 

1991-1992 (All Snowden) BIN 1 BIN 2 BIN 3
Harvest date Sep. 18, 1991 Sep. 18, 1991 Sep. 13, 1991
Harvest temperature 25.6°C 25.6°C 23.9°C
Suberization run times 24 hours 24 hours 24 hours
Cooling run times 24 hours 24 hours 24 hours
Ventilation rate 56 m3/ t 56 m3/ t 56 m3/ t

Slot velocity 232 m/ min 232 m/ min 232 m/min
Desired R. H. 95% 95% 95%

Start Cooling/ End Precond. Oct. 16, 1991 Oct. 16, 1991 Oct. 4, 1991
CIPC Application Nov. 20, 1991 None None

Set cooling rate (actual) 0.1°C/day(0.09) 0.3°C/day(0.16) 0.05°C/day(0.27)
Start holding Jan 15, 1992 Jan 10, 1992 Nov. 15, 1991
Holding run times 3/ 12 hours 3/ 12 hours 3/ 12 hours
Holding temperature 72°C 56°C 39°C

Market date (exp. ended") Ian. 18, 1992* Ian 18, 1991* May 7, 1992_
TABLE 3;2_b Storage Dates and Parameters (English Units)

1991-1992 (All Snowden) BIN 1 BIN 2 BIN 3

Harvest date Sep. 18, 1991 Sep. 18, 1991 Sep. 13, 1991
Harvest temperature 78°F 78°F 75°F
Suberization run times 24 hours 24 hours 24 hours
Cooling run times 24 hours 24 hours 24 hours
Ventilation rate 1.5 cfm/cwt 1.5 cfm/cwt 1.5 cfm/cwt
Slot velocity 760 ft/ min 760 ft/ min 760 ft/ min
Desired R. H. 95% 95% 95%

Start Cooling/ End Precond. Oct. 16, 1991 Oct. 16, 1991 Oct. 4, 1991
CIPC Application Nov. 20, 1991 None None

Set cooling rate (actual) 0.2°F/day(0.16) 0.6°F/day(0.29) 1.0°F/day(0.48)
Start holding Jan 15, 1992 Jan 10, 1992 Nov. 15, 1991
Holding run times 3 / 12 hours 3 / 12 hours 3/ 12 hours
Holding temperature 45°F 42°F 39°F

Market date (e52. ended") Ian. 18, 1992* Ian 18, 1991* Mav 7, 199;_

 

25

TABLE 3.3a Storage Dates and Parameters (Metric Units)

 

 

 

 

 

w-199SIA11 Snowden) BIN 1 BIN 2 BIN 3
Harvest date Oct. 5, 1992 Oct. 5, 1992 Sep. 16, 1992
Harvest temperature 15°C 15°C 21.7°F
Suberization run times 24 hours 24 hours 24 hours
Cooling run times 24 hours 24 hours 24 hours
Ventilation rate 56 m3/ t 56 m3/ t 56 m3/ t
Slot velocity 232 m/ min 232 m/ min 232 m/ min
Desired R. H. 97% 97% 97%

Start Cooling/ End Precond. Oct. 25, 1992 Oct. 25, 1992 Oct. 15, 1992
CIPC Application None None None

Set cooling rate (actual) 0.3°C/day(0.17) 0.3°C/day(0.19) 0.5°C/day(0.26)
Start holding Dec. 9, 1992 Dec. 17, 1992 Nov. 25, 1992
Holding run times 3/ 12 hours 3/ 12 hours 3/ 12 hours
Holding temperature 72°C Approx. 55°C 39°C

Market date March 31, 1993 March 30, 1993 April 21. 1993
TABLE 3.3b Storage Dates and PaLameters (English Units)

@1993 (All Snowden) BIN 1 BIN L BIN 3
Harvest date Oct. 5, 1992 Oct. 5, 1992 Sep. 16, 1992
Harvest temperature 59°F 59°F 71°F
Suberization run times 24 hours 24 hours 24 hours
Cooling run times 24 hours 24 hours 24 hours
Ventilation rate 1.5 cfm/cwt 1.5 cfm/cwt 1.5 cfm/cwt
Slot velocity 760 ft/ min 760 ft/ min 760 ft/ min
Desired R. H. 970/0 970/0 970/0

Start Cooling/ End Precond. Oct. 25, 1992 Oct. 25, 1992 Oct. 15, 1992
CIPC Application None None None

Set cooling rate (actual) 0.54°F/ day(0.31) 0.54°F/day(0.34) 0.9°F/day(0.47)
Start holding Dec. 9, 1992 Dec. 17, 1992 Nov. 25, 1992
Holding run times 3/ 12 hours 3/ 12 hours 3/ 12 hours
Holding temperature 45°F Approx. 42°F 39°F

flrket date March 31. 1993 March 30, 1993 April 21I 1993

 

26
3.2.7 Weight Loss

Four sample bags of about 9 kg (20 lbs) each were placed at three levels
in each bin to determine the weight loss during storage. The bags were placed
on the floor of the storage, at 1.5 m (5 ft) and at 3 m (10 ft).

3.2.8 Sampling

Bins 1 and 2 were sampled weekly during the 1990-1991 and 1991-1992
seasons, and biweekly during the 1992-1993 season. For the 1991-1992 season,
bin 3 was sampled weekly until December 1, 1991 and thereafter was sampled
biweekly. For the 1992-1993 season, bin 3 was sampled biweekly until January
19, 1993 and monthly thereafter.

15 tuber samples were taken from the top of the pile and from three
levels within the pile. The samples were chipped and analyzed for sugars in
the manner described in section 3.3, using all 15 tubers for chips and 8 tubers
for sugar samples.

3.2.9 Reconditioning

On April 7 1992, samples from bin 3 were transferred to warmer
storages for reconditioning. Three treatments were placed in storages at 83°C
(47°F), 11.7 (53) and 15.5 (60). A forth treatment was held at 83°C for one
week, 117°C for one week and then at 155°C for the remaining time. Ten
tubers from each treatment were sampled weekly for fry color and sugar
levels.

On April 21 1993, samples from bin 3 were transferred to storages at

125°C (54.5°F) and sampled biweekly for 6 weeks.

4. RESULTS AND DISCUSSIONS

The sugar samples collected during the 1990-1991 and 1991-1992 seasons
were analyzed using a YSI Model 27 sugar analyzer. The lower limit of the
Model 27 analyzer under good operating conditions is approximately 0.1 g/ l
which corresponds to a glucose level of 0.022%. The sucrose levels were
calculated from the glucose readings before and after reduction of the sample
with invertase. Since the critical glucose level for darkening of processed chips
as determined in this study falls below the level of accuracy for the YSI Model
27, the data collected during the 1990-1991 and 1991-1992 storage seasons is
limited in its application.

A YSI Model 2700 sugar analyzer was purchased by the Michigan
Potato Industry Commission during the summer of 1992 and was used for
analysis of samples from the 1992-1993 season.

Data from 1990-1991 and 1991-1992 field research bins are listed in
Appendices A and B. Table 4.1 lists the sugar levels and chip color (1992-1993
season) for the four levels in the three field research bins. Tables 4.2a and 4.2b
display the sugar levels and chip color Snowden and Atlantic potatoes in the
laboratory experiments. Plots and discussion are included later in this chapter.
4.1. CORRELATION BETWEEN CHIP COLOR AND SUGARS, 1992-1993
4.1.1 Results of Field Storage Experiments

The sugar data of Snowden samples from the three research bins in
1992-1993 were sorted by chip color using the Snackfood Association’s 1 to 5

color chart using 0.5 steps (Snackfood Association, undated). The average,

27

28

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31

standard deviation and range of the glucose and sucrose levels for each chip
color are displayed in Table 4.3.

The linear correlation between chip color and glucose levels had an R2 =
0.80/(p-value < 0.001). A poorer correlation was found between the chip color
and sucrose levels (R2 = 0.58 with a p-value < 0.001).

Figure 4.1 is a plot of chip color versus % glucose for all samples from
the three bins. The portion of the curve that is of primary interest is for chip
colors below 2.5 or 3.

All the samples were sorted by glucose in ascending order and divided
into intervals. The percent of acceptable samples/ interval were calculated for
each interval using an acceptable color of 1.5 and 2.0 (SFA). The interval
width started at 0.001% for low sugar levels (0.004—0.005°/o) and was increased '
as the sugar level rose above 0.01%. This was necessary to incorporate a
number of samples in each interval. Each interval had a least 5 samples. The
percent of acceptable samples per interval versus glucose level are plotted in
Figure 4.2. Curves were fit to the data and are listed in Appendix C.

4.1.2 Results of Late Storage Season Sweetening Experiments

Chip color and the corresponding sugar levels for the Snowden and
Atlantic potatoes in the late storage sweetening experiments are displayed in
Table 4.4. The linear correlation coefficients for the Snowden chip color with
glucose and sucrose levels were 0.63 and 0.51, respectively. The correlation

coefficients for Atlantic chip color with glucose and sucrose levels were 0.50

and 0.38 (all p—values < 0.001).

32

TABLE 4.3. Snowden sugar levels (%)' for all samples from
field storage bins grouped by color (SFA)", 1992-
1993.

% Glucose

 

 

 

 

Color§SFAz Average Standard Dev. Low High #Samgles

.003 0. 001 0.001 0.007 44
1.5 0.006 0.003 0.002 0.015 52
2.0 0.011 0.005 0.005 0.025 16
2.5 0.020 0.007 0.007 0.030 12
3.0 0.031 0.020 0.011 0.078 12
3.5 0
4.0 0.093 0.025 0.071 0.120 4
4.5 0.120 0.042 0.097 0.183 4
5.0 0.146 0.034 0.096 0.200 10

% Sucrogg
ColorlSFA) Average Standard Dev. Low High #Samgles

1.0 .076 0.016 0.044 0.114 44
1.5 0.078 0.022 0.035 0.120 52
2. 0 0.078 0.031 0.035 0.137 16
‘2. 5 0.098 0.039 0.058 0.164 12
3. 0 0.137 0.002 0.046 0.275 12
3. 5 0
4.0 0.250 0.020 0.228 0.273 4
4. 5 0.222 0.045 0.158 0.262 4
5. 0 0.198 0.032 0.153 0.260 10

'% weight on a fresh weight basis.
"SFA, Snackfood Association color rating.

33

 

 

 

 

 

 

 

 

 

 

 

 

 

Research bins, 1992-1993
5 H F H
.11 I u
4 ------------------------------ n ------- {nu-- an- -------------------------------- .
2 1
u.
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Late storage sweetening experiments
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1992-1993. ' % fresh weight basis. " Snackfood Association.

1

 

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8

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8

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Fig 4.2 Probability of SFA color for levels of glucose in chip samples for
the 1992-1993 storage season (research bins).

35

TABLE 4.4. Sugar levels (%)' for all samples from the late
storage season sweetening experiment grouped by

'0

color (SPA) , 1992-1993.

 

 

SNOWDEN
% Glucose

ColorlSFA) Averagg Standard Dev. Low High #Samples
1.0 0.003 0.002 0.001 0.014 47
1.5 0.008 0 007 0.000 0.028 48
2.0 0.015 0.006 0.007 0.027 14
2.5 0.017 0.008 0.003 0.036 16
3.0 0.041 0.028 0.010 0.086 8
3.5 0.056 0.007 0.051 0.085 2
4.0 0.103 0.026 0.085 0.121 2
4.5
5.0 0.164 0.164 0.164 1

% Sucrose

 

 

 

 

 

 

 

 

Color(SFA) Averagg78tandard Dev. gow High, #Samplgg
1.0 0.067 0.032 0.022 0.163 47
1.5 0.103 0.049 0.032 0.288 48
2.0 0.174 0.072 0.035 0.307 14
2.5 0.182 0.081 0.086 0.383 16
3.0 0.190 0.039 0.134 0.239 8
3.5 0.261 0.017 0.249 0.273 2
4.0 0.252 0.036 0.226 0.277 2
4.5
5.0 0.327 0.327 0.327 1

ATLANTIC

% Glucogg

Color(SFAL Average Standard Dgy. Low High #Samples
1.0
1.5 0.007 0.006 0.002 0.022 17
2.0 0.013 0.006 0.004 0.030 56
2.5 0.014 0.007 0.003 0.029 28
3.0 0.033 0.028 0.008 0.108 19
3.5 0.079 0.043 0.041 0.126 3
4.0 0.058 0.035 0.035 0.109 4
4.5 0.102 0.040 0.057 0.132 3
5.0

% Sucrosgf

ColorlSFAz Average Standard Dev. Low High #Samples
1.0
1.5 0.081 0.040 0.019 0.158 17
2.0 0.087 0.047 0.025 0.292 56
2.5 0.119 0.079 0.028 0.303 28
3.0 0.145 0.070 0.054 0.301 19
3.5 0.255 0.061 0.185 0.299 3
4.0 0.338 0.204 0.184 0.626 4
4.5 0.359 0.206 0.154 0.565 3
5.0

'% weight on a fresh weight basis.
"SPA, Snackfood Association color rating.

36

Figure 4.1 shows a plot of chip color versus % glucose for all Snowden
samples in the late season storage sweetening experiment.
4.1.3 Discussion of Chip Color and Sugars in Field Storage Experiments

The correlation between chip color and glucose levels was fairly high for
the bin storages which verified glucose levels as a good indicator of chip color.
A poorer correlation was found between chip color and sucrose levels. From
Figure 4.1, it can be seen that the correlation between chip color and glucose
level is not linear, but for chip colors below 2.5 or 3 this relationship can be
used.

To assure acceptability of potatoes for chippingxa Snackfood Association
(SPA) rating of 1 or 1.5 is required. A rating of 2 is considered marginal, being
acceptable under some market conditions and not under others. For the
Snowden potatoes stored in 1992-1993, a sample with a glucose level of
0.0075% (fresh weight basis) will have 90% probability of having a color of 1 or
1.5 (from Figure 4.2). A sample with a glucose level of 0.01% will have a 90%
probability of having a color of 1, 1.5 or 2.
4.1.4 Discussion of Chip Color and Sugars in Late Storage Season
Sweetening Experiments

The tubers in the late storage season sweetening experiment were
subjected to more stresses (sprout inhibitor treatment, heat treatments and
rapid temperature changes), and would be expected to have a larger variation
and between samples. This would lead to a poorer correlation between the

chip color and glucose. The correlations between chip color and glucose levels

37

for the Snowden potatoes in the late storage season sweetening experiment
were somewhat lower than in the field storage experiments. The correlation
between chip color and sucrose was similar.

The correlation coefficients of the Atlantic samples were lower than
those of the Snowden. The sugar levels and quality of the Atlantic tubers at
harvest were marginal in quality for long term storage. During the heat
treatments, approximately 20% of the Atlantic tubers had to be discarded to
prevent them from rotting other tubers. Approximately 7% of the Snowden
tubers were discarded.

The average glucose levels of samples with chip color (SFA) 1 were the
same for the late storage season sweetening experiment and the field research
bins. At higher color levels, the samples from the physiological aging
experiment were slightly higher in glucose. This is probably due to the overall
higher sugar levels and higher variability in this experiment. The sucrose
levels corresponding to the color ratings were also higher in the late storage
season sweetening experiments than for the field storage bins.

The average glucose and sucrose values for the Atlantic potatoes were
comparable to the Snowden, but the variation about the average was larger.
4.2 VARIABILITY IN SAMPLE SUGAR LEVELS FROM THE FIELD
STORAGE BINS

The research bins had a sample taken at each of four levels. Figure 4.3
displays the glucose levels at four heights from the floor - 0.6, 1.7, 3.0 and 4.3

meters for the 1992-1993 storage season.

38
Bin 1, holding temperature 7.2 C

 

   

    

 

 

    

      

    
   
 
    
 

       

        

 

  
  
   
 
 

   
 
 
    

 

 

 

 

 

 

 

 

gem. 3* 30%

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0.3.8....» 031895»

, 1.7, 3.0 and 4.3 m (top)
ferent for bin 3.

 

0.6m -' 1.7m

=3.0m A top

— Term.

 

 

 

Bin temperature and glucose levels at 0.6
above bin floor. Note: Glucose scale is dif

Fig. 4.3

39

Figure 4.4 displays the sucrose levels.

The Michigan Bin Monitoring Program uses a sample from the top of
the bin as a representative sample of the bin. If a single sample from a potato
bin is going to be used in monitoring the sugar levels in a bin, it is important
to understand the variability that can be expected from a sample and to know
how representative the sample is of the entire bin.

4.2.1 T Test for Difference between Means

A statistical paired t test was performed to test the hypothesis that the
difference between paired means of sample locations was zero at a 0.05 level
of significance. Appendix D.1 contains the results of the paired t test for all
the samples in the three bins during the 1992-1993 storage season. The
variability of the glucose readings increased as the glucose levels increased. At
a chip color of 1, the standard deviation of the glucose reading was 0.001 and
at a chip color of 2.5, the standard deviation was 0.007 (from table 4.3). When
bin sugar levels are to be used as an aid in storage management, the primary
range of interest is for low sugar levels (anticipating increases leading to
problems). A second paired t test was performed on a trimmed set of data for
each bin for lower glucose levels (below 0.02% glucose or harvest through
1/ 19/ 93 for bins 1 and 2, and through 11/ 25/ 92 for bin three (Appendix D.2)).

Summaries of the paired 2-tail probabilities and the signs of the t values
(a negative sign indicates a larger mean by the second sampling level in the

paired test) are displayed in Table 4.5.

40
Bin 1, holding temperature 7.2 C

085% o\o gm 0\o g 0\o

 

 

 

       

       

 
  

   
 
 

    

   

   

 

         
  

   
    

 
    

    

   
    

 

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12130192

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11/18/92

Bin temperature and sucrose levels at 0.6, 1.7,

above bin floor-

10/2819'2'

V

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41

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42

4.2.2 Results of t test

For the trimmed data, there was no evidence of differences, at the 0.05
level of significance, in the means of glucose or sucrose between 0.6 and 3.0 m
or between 1.7 and 4.3 m. For all the paired t tests between 0.6 and 3.0 m, the
sign of the t value (given in Table 4.5), is negative indicating that the means
difference of 0.6 m paired to 1.7 m is negative (1.7 m means are greater than
the 0.6 m means). A similar situation exits between samples at 3.0 m and 4.3
m with means at 4.3 m being higher than means at 3.0 m.

4.2.3 Discussion of Variability in Tuber Sugar Levels in Samples from
Storage Bins

Plots of the sugar levels at the 4 sampling levels (Figures 4.3 and 4.4)
show that samples from a given sampling location follow trends similar to
trends of the other sampling locations. The trimmed data was more
representative of the sugar levels that would be found in a bin stored for
chipping potatoes as the temperatures and sugar levels correspond to those of
commercial storages.

The findings that samples from heights of 0.6 and 3.0 m show no
evidence of differences and samples from heights of 1.7 and 4.3 m show no
difference from each other but are greater than 0.6 and 3.0 m, can be attributed
to an early assumption in the sampling techniques. The order in which the
potato samples from the four locations in the bins were juiced, was kept the
same. Cleaning and changing the filter is a time consuming process. As the

samples were all from a given bin (replicate samples) the filter was changed

43

every two samples. Therefore juice from heights of 1.7 and 4.3 m would be
rinsed through pulp from samples at 0.6 and 3.0 m respectively.

For the trimmed data from the three research bins (found in Appendix
D2), the average increase of 1.7 m over 0.6 m was 0.001% (520.0005) for
glucose and 0.16% (0.07) for sucrose. The average increase of 4.3 m over 3.0 m
was 0.002% (5:0.0009) for glucose and 0.17 (0.08) for sucrose. The increases in
sugar levels at 1.7 and 4.3 m due to sampling procedures were nearly the same
and without the sampling difference the four sampling locations would all be
equivalent. Therefore, tuber samples from the top of a potato bin will provide
a representative sample as long as recommended storage procedures are
followed.

Analysis of the sugar levels in the field research bins in later sections of
this chapter use the average of the four sampling locations as the bin sugar
level. The increase in sugar levels added due to the error in sampling
procedures, would be one-half of the increases given above, or approximately
6.5% for glucose and 8.5% for sucrose (using average glucose at 0.01% by
weight and sucrose at 0.1% by weight). The effect on the results and
recommendations would be negligible.

Bin 3 (holding temperature 4.4°C) had elevated glucose levels from the
top of the bin (4.3 m level was at least 20% above the other three levels), after
intermittent fan operation was initiated. Bin 2 (holding temperature 55°C) also
experienced higher glucose levels on the top level when the temperature was

at the holding temperature and fans were being operated intermittently. These

44

higher glucose levels can be attributed to above pile temperature fluctuations
the potatoes were exposed to during intermittent fan operation. Commercial
operators should be aware of this if a bin is being stored near the lower
temperature limits for a variety. This problem is amplified in the scaled down
research bins as compared to commercial storages due to the smaller size of
the bin.
4.3 LATE SEASON STORAGE SWEETENING EXPERIMENT

The recommended procedures for the application of sprout inhibitor
allows the tubers to suberize and wound heal for at least two weeks before
treatment. However in this experiment, the storages were 90 minutes from the
facility for sprout inhibitor treatment. The treatments in the experiment would
require four different times for CIPC application, so the CIPC was applied
before the heat treatments and the suberization took place.

In this experiment it was assumed that this would not be of any major
consequence. The difficulty in applying the sprout inhibitor to small batches
was avoided but the wound healing of the tubers was sacrificed. The early
treatment with sprout inhibitor had a negative effect on the wound healing
ability of the tubers. This was most evident in the Atlantic potatoes which
were of marginal quality for long term storage when they were harvested.

In the later months of this experiment, tubers were becoming soft due to
moisture loss in the 10 and 125°C storages. The tubers were much softer than
in a commercial storage where higher humidities are maintained. This did not

appear to have an effect on the sugar level or chip color, but did make the

potatoes more difficult to slice.
4.3.1 Snowden Variety Late Storage Sweetening
4.3.1.1 Results of Snowden stored at 72°C

Plots of the glucose and sucrose for heat treatments of 0, 1, 2 and 4
weeks are displayed in Figures 4.5a, 4.5b, 4.5c and 4.5d. Treatment 1 (no heat
treatment) sugar levels, especially glucose, jumped immediately after being
transferred from the 155°C to the 72°C. Glucose levels remained well above
0.01% and tubers produced unacceptable colored chips (Table 4.2a) for 12
weeks (through 1/ 18/ 93) after the transfer, but did drop below 0.01% after 14
weeks. Both the glucose and sucrose levels declined until late in March.
Sucrose started to rise on 4/ 12/ 93 and the glucose levels started to rise 2
weeks later. Sucrose levels had risen above 0.1% on 4/ 26/ 93. Glucose levels
rose above 0.01% (chip color 2) on 6/ 7/ 93 (8 weeks after a rise in sucrose and
6 weeks after a rise in glucose were detected).

Treatment 2 (1 week heat treatment) had glucose levels rise to above
0.014% on 12/ 21 / 93 and 1/ 14/ 93 (7 and 9 weeks after transfer from 15.5 to
72°C). Sucrose and glucose levels started to decline on 1/ 18 / 93 (11 weeks
after the transfer) and glucose levels had fallen below 0.01% and sucrose below
0.1% 2 weeks later. Sucrose levels held or fell through 3 / 28 / 93. On 4/ 12 / 93
sucrose levels had started to rise and on 4/ 26/ 93 had risen to 0.15% and
continued to rise. Glucose continued to fall until a rise on 4 / 26 / 93. Both the
glucose and sucrose continued to rise with the chip color (Table 4.2a)

becoming unacceptable 8 weeks after the sucrose had started to rise and 6

46

 

 

L0.06

“0.02

 

°/o Ghacose

 

 

 

 

 

 

P001
12/03/92 1 05/20/93 °
11/05’92 12/31/92 02/2993 04/22/93 06/17/93
[ =- Glucose A Sucrose — Gkncose. M2089 - - Sucrose. M20891
Fig. 4.5a Sugar levels for Snowden variety with no heat treatment and

72°C holding temperature.

 

 

 

 

 

 

1090092 T 1203/92 F 01/20/93 ‘ 0540/93 0
11/05/92 12/31/92 02/25/93 04/22/93 06/17/93

 

[ a Glucose 4. Sucrose — Glucosem2=.78-- Sucrose.r'\2=.91 I

 

Fig. 4.5b Sugar levels for Snowden variety with 1 week heat treatment at
267°C and 72°C holding temperature. '

47

 

0.04

 

"0.02

0/0 am

-0.01

 

 

 

 

 

' 1 01 05/20/93 0
11/05/92 12/31/92 02/25/93 04/22/93 W17/m
[a Glucose A Sucrose —Gb.rcose.r"2=.60-- Sucrose.r"2=.83]

 

Fig. 4.5c Sugar levels for Snowden variety with 2 week heat treatment at
267°C and 72°C holding temperature.

 

”.70 A
I

 

 

 

 

 

12/0'3/92 01/2'0/93 ' 03/25/93 ‘ 05/20/93 0
11/05/92 12/31/92 02/25/93 04/22/93 06/17/93

 

[a Glucose A Sucrose —G,r"2=.76-- S,r'\2=.79]

 

Fig. 4.5d Sugar levels for Snowden variety with 4 week heat treatment at
267°C and 72°C holding temperature.

48

weeks after the glucose started to rise.

Treatment 3 (2 week heat treatment) had sucrose levels jump to around
0.1% on 12/4/92 (4 weeks after transfer to 72°C) and hold near that level for
about 8 weeks (through 2/ 1/ 93) before declining. Glucose levels also jumped
4 weeks after the transfer, but continued to climb for 6 weeks more to a level
above 0.025% on 1/ 18 / 93, before they declined to levels below 0.01%. Chip
colors (Table 4.2a) declined to marginal levels as glucose increased, and then
improved as sugars decreased. Sucrose levels started to rise on 4/ 12/ 93, were
above 0.1% 2 weeks later and continued to rise. Glucose levels started to rise
4/ 26/ 93 and 2 weeks later levels rose above 0.01% and chip color declined.

Glucose levels for treatment 4 (4 week heat treatment) reacted similarly
to levels in treatment 3 with a rise starting on 12/ 4/ 92 (4 weeks after the
temperature transfer). Sucrose levels never fell much below 0.1% and 6 weeks
after transfer to 72°C, started to rise and were above 0.2% 2 weeks later.
Sucrose and glucose fell on 2/ 1/ 93 and 2/ 15/ 93 respectively. Sucrose levels
started to rise on 3/ 28/ 93 and glucose started to rise on 4/ 26/ 93. Glucose
levels were above 0.01% on 4/ 26 / 93 and chip color was marginal at best
throughout the much of the storage.

Plots of power curves (of the form: sugar level = timea + b, Appendix E)
fitted to the rises in sugar levels in late storage for the 4 treatments are
displayed in Figures 4.5a-d and are repeated in Figures 4.6a and 4.6b. The
curves were fit to points following a ’local’ minimum sugar value. It can be

seen that glucose levels for treatments 1 and 2 increased at the same time.

49

Treatment 3 intersected the glucose level of 001% about 7 days before the lines
for treatments 1 and 2. Treatment 4 glucose levels increased above 0.01%
approximately 25 days before treatments 1 and 2. The sucrose lines for
treatments 1, 2 and 3 all passed through the 0.1% line very close to each other
and treatment 4 was offset by more than a month but never was as low as
0190

4.3.1.2 Results of Snowden stored at 10.0°C

Plots of the glucose and sucrose for treatments 1, 2, 3 and 4 are
displayed in Figures 4.7a, 4.7b, 4.7c and 4.7d. Treatment 1 (no heat treatment)
had glucose levels generally falling gradually (to below 0.003%) over the
duration of the storage until 3 / 28 / 93 when an increase started. On 5/ 10/ 93 (8
weeks later) glucose levels had risen to 0.015% and chips were unacceptable in
color (SFA color = 2, Table 4.2a). Sucrose levels gradually fell from levels
around 0.075 early in the storage to 0.03% on 2/ 15/ 93 and then started to rise
at the same time that glucose levels had risen and were above 0.1% on
5/10/93.

Treatment 2 (1 week heat treatment) glucose held nearly constant
through storage (0.004%) and started to rise on 3/ 16/ 93. On 4/ 26/ 93 (6 weeks
later) glucose levels had risen to 0.02% and chips had darkened (SFA color 2
2). Sucrose levels were more variable throughout the storage time but did
drop down to levels comparable to treatment 1 on 2/ 15/ 93. Rises in sucrose
corresponded to rises in glucose and sucrose levels rose above 0.1% on

4/26/93.

0.04

 

0.03-1

% Glucose
0
§

0.01-1

 

 

 

 

02901/90 F '03/0'1/96 ‘ '03/29793' 1 '04/26/93 T 05/24/93 ‘ '06/21/93
02/15/93 03/15/93 04/12/93 05/10/93 06/07/93

 

[—0week----1week—2week-- 4weelrj

Fig. 4.6a Glucose late storage season sweetening for Snowden variety
stored at 72°C. (183°C after 3/ 16/ 93)

 

ooooooooooooooooooooo

% Sucrose

 

 

 

 

02901/93‘ T‘0T3/oT/93' ' '03/29/93’ ‘ ‘04/26/93' ' 115/2293‘ ' TOG/{USS
02/15/93 03/1 04/12/93 05/10/93 06/07/93

 

[—0week----1week—2week-- 4week]

Fig. 4.6b Sucrose late storage season sweetening for Snowden variety
stored at 72°C. (183°C after 3/ 16/ 93)

51

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

o ‘ 0.04
15.50
"“l
0.34» ------------------------------------------------------------------------------------ 1
g 02» ----------------------------------------------------------------------------
(D
0°
45
0.1-0m; --------------------------------------------------------------
‘ A
as ‘
a: a a
1&06/92 ‘ 12/ 01 05/20/93
11/05/92 12/31/92 02/25/93 04/22/93 06/17/93
I =1 Glucose A Sucrose — Glucose. $23.85 -- Sucrose. M2092]
Fig. 4.7a Sugar levels for Snowden variety with no heat treatment and
100°C holding temperature.
04 0.04
26.70
15.50
10.00
0.30 ----------------------------------------------------------------------------------- «0.03
a
g 02-- -------------------------------------------------------------------------- , 1 ------- «0.02 g
o\° o\°
A
AL
0.1T-x-“x -------- A "-"A- """"""""" A °°°°°°°°°°°°°°°° ) ’ .0.01
‘ A
do
an a a a a ’
7 a e 2
109 ' 12/0‘3/92 F 01/2‘E93 03/25/93 F 05/20/93 0
11/05/92 12/31/92 02/25/93 04/22/93 06/17/93
[ =1 Glucose A Sucrose — Glucose. M2=.85 -- Sucrose. M2=.78 I

 

Fig. 4.7b Sugar levels for Snowden variety with 1 week heat treatment at
267°C and 100°C holding temperature.

52

 

0.04

 

 

“0.02

t
x;
'\
: \
. \
% Glucose

» -------------------------------------------------------------- 4 ------------------- «0.01

 

 

 

0
06/17/33

 

 

I = Glucose A Sucrose — Glucose. M2281 -- Sucrose. M20861

 

Fig. 4.7c Sugar levels for Snowden variety with 2 week heat treatment at
267°C and 100°C holding temperature.

 

0.04

 

% Sucrose

-0.01

 

 

 

 

12/03/92 01/26/93 5 03/25/93 ' 05/20/93 0
11/05/92 12/31/92 02/25/93 04/22/93 06/17/93

 

L: Glucose A Sucrwe — Glucose.r'\2=.80-- Sucrose,r*\2=.80 I

 

Fig. 4.7d Sugar levels for Snowden variety with 4 week heat treatment at
267°C and 100°C holding temperature.

53

Glucose levels for treatment 3 (2 weeks heat treatment) were down to
0.002% on 3/ 1/ 93. Sucrose levels fell gradually during storage from around
0.1% down to 0.03% on 3 / 1/ 93. Both the glucose and sucrose rose gradually
for 4 weeks after 3 / 1/ 93 and on 4/ 12/ 93 (6 weeks later) the glucose had risen
to 0.017% and sucrose had risen to 0.14%. SFA chip color was 2 on 4/ 12/ 93
and 2 weeks chip color was 3 and glucose had risen to 0.05%.

The glucose level for treatment 4 (4 weeks heat treatment) held at
around 0.003% until 3 / 1/ 93 when it started to rise. Sucrose held around
0.09% until 3 / 1/ 93 when it rose to 0.14%. The sucrose level had continued to
rise and 2 weeks later the chip color was 2.5.

Plots of power curves fitted to the rises in sugar levels in late storage
for the 4 treatments are displayed in Figures 4.8a and 4.8b. The glucose curves
for treatments 4, 3 and 2 cross the 0.01% glucose level ahead of treatment 1 by
approximately 44, 26 and 11 days respectively. The sucrose levels for
treatments 4, 3 and 2 reach 0.1% approximately 79, 15, and 19 days before
treatment 1.
4.3.1.3 Discussion of Temperature Transfer

The transfer of the tubers from 15.5 to 72°C appeared to cause an
increase in the glucose levels and a darkening of chips for all treatments. All
four treatments were able to recover to glucose levels below 0.01% with
acceptable chips but this took approximately 14 weeks.

Treatments 1 and 2 resulted in similar glucose levels (0.018 and 0.014%

respectively) though treatment 1 reacted much more rapidly. The 1 week heat

 

 

 

 

 

0.04

0.03«
l .
o 002
0"

0.01.

02900/93 ' l03/0‘1/93 ' 03/29/93 F r04/26/93 ' 052493 F 206/21/93

02/15/93 00/15/93 04/12/93 05/10/93 M783

 

I—Owesk----1week—2week-- 4wesk]

 

Fig. 4.8a Glucose late storage season sweetening for Snowden variety
stored at 100°C.

 

0.3"1

% Sucrose
.0
'1‘

0.1-

 

 

 

 

02901/93 ' ’03/0F1/93T' 03/29/93 ‘ '04/26/93 ' 052493 T *06/21/93
02/15/93 03/15/93 04/12/93 05/10/93 06/07/93

 

I— Oweek-m1week— 2week-- 4weekI

 

Fig. 4.8b Sucrose late storage season sweetening for Snowden variety
stored at 100°C.

55
treatment for treatment 2 appeared to delay the rise in glucose, and to a
limited degree, reduced the magnitude of the rise.

The glucose levels that resulted from the temperature transfer for
treatments 3 and 4 both were above 0.025%. It is uncertain why these two
glucose levels would be higher than treatments 1 and 2. Treatment 4 also had
an increase in sucrose accompanying the rise in glucose.

The Snowden potatoes transferred from 155°C to 100°C had no
detectable response in the sugar levels, other than a single reading in treatment
4 two weeks after the transfer. This reading corresponded to an acceptable
chip sample and was not considered important.
4.3.1.4 Discussion of Snowden at 72°C

The inadvertent rise in temperature that started on 3 / 1/ 93 and warmed
the tubers to 18.3 over 3 weeks time was not intended but once it had occurred
the decision was made to maintain that temperature rather than to recool the
tubers. The main effect of the warming was probably to increase the
respiration rate of the tubers and to advance late storage season sweetening

The rises in the sucrose levels for 0, 1 and 2 week heat treatments were
first detected on 4/ 12/ 93. The rises in glucose levels for the 0, 1 and 2 week
treatments were first detected on 4/ 26/ 93. The rate of increase of glucose for
the O and 1 week heat treatment were the same and the 2 week heat treatment
increased above 001% about a week earlier. Treatment 4 (4 weeks heat
treatment) increased the initial sucrose levels and advanced the late storage

season sweetening much more than the shorter treatments. Glucose levels for

56

treatment 4 were never as low as for the other treatments. Treatment 4 did
rise above 001% about 25 days before treatments 1 and 2, but the rate of
increase was comparable to the rates for 1 and 2.

The rise in sucrose levels was detected 2 weeks before the rise in
glucose for all treatments with a holding temperature of 720C (later warmed
to 183°C). For the heat treatments of 0 and 1 week, the chips went off color 8
weeks after sucrose started to rise and 6 weeks after glucose levels started to
rise.
4.3.1.5 Discussion of Snowden at 100°C

The time at which the glucose levels for the four treatments reached
0.01% were quite distinct and evenly spread. Samples from the heat
treatments of 0, 1 and 2 weeks started to increase in sugars at roughly the
same time. Increasing the length of the heat treatment increased the rate at
which the glucose levels rose. This may also apply to other stresses imposed
on potatoes in early storage or during harvest.

The time at which the sucrose rose above 0.1% for treatment 4 was
about 80 days before treatment 1. Treatments 2 and 3 preceded treatment 1 by
around 15 and 19 days respectively. The 0.1% level is probably not a very
relevant level of interest for treatment 4 as the sucrose levels were not that far
below 0.1% to start with. The sucrose levels for treatment 2 increased to above
0.1% before treatment 3. Figures 4.7b and 4.7c show that the sucrose levels
were variable for‘both these treatments. Visual inspection of Figure 4.8a

shows that the slopes on the glucose curves increase with increasing treatment.

57

For treatment 1 (no heat treatment) the rises in glucose and sucrose
were detected 8 weeks before the chip samples went off color. For treatments
2 and 3 (1 and 2 week heat treatments) both the glucose and sucrose started to
rise 6 weeks before the chips went off color.

Treatment 4 (4 week heat treatment) rises in glucose and sucrose were
detected 4 weeks before the chips went off color.

The longer the length of heat treatment the higher the rate of sugar
accumulation.
4.3.1.6 Comparison of Late Storage Season Snowden Sweetening at 72°C
and 100°C

For the potatoes that received no heat treatment, the Snowden tubers
stored at 72°C sweetened approximately 4 weeks after the tubers stored at
100°C (glucose above 0.01% and colored chip >1.5 on 6/ 7/ 93 and 5/ 10/ 93
respectfully). Both sets of tubers were transferred to holding temperature on
10/ 23/ 93. The tubers stored at 72°C were gradually warmed to 183°C
between 3 / 1/ 93 and 3 / 21 / 93. The rate of aging would have been faster at the
183°C than at 72°C, and without this warming it is assumed that the tubers
would have stored longer without sweetening. It can be concluded that
Snowden tubers at 72°C age at least 4 weeks slower than tubers at 100°C over
8-9 months of storage. A value of 8 weeks may be closer to the actual
difference but no evidence to support this was collected.

Commercial storages will probably experience lower sugar levels than in

this experience (personal communication with managers sampling bins in

58

Michigan). This should have a positive effect on using the sugars as predictors
of the onset of sweetening associated with late season storage. The lower
sugar levels‘will allow a larger increase in sugars before unacceptable chip
result, and allow easier detection of increases. The rate at which the sugars
will rise should be lower or similar as long as no additional stresses have been
imposed on the tubers.

4.3.2 Atlantic Variety Late Storage Sweetening

The quality of the Atlantic potatoes for chipping was the highest at
harvest and thereafter only a limited number of samples were much better
than marginal. The variability of the Atlantic samples was high.
4.3.2.1 Results of Atlantic Stored at 100°C

Plots of the glucose and sucrose for treatments 1, 2, 3 and 4 are
displayed in Figures 4.9a, 4.9b, 4.9c and 4.9d. Glucose and sucrose levels for all
treatments rose 2 to 4 weeks after the transfer from 15.5 to 100°C.

Treatment 1 (no heat treatment) glucose levels fell to about 0.01% on
2 / 15 / 93 and gradually rose thereafter. Sucrose levels for treatment 1 fell to
below 0.05% on 3/ 1/ 93 and gradually increased after that.

Glucose levels for treatment 2 (1 week heat treatment) dropped below
0.004% on 1/ 4/ 93 and gradually rose thereafter reaching 0.01% on 3/ 1/ 93.
Sucrose levels dropped to 0.05% on 2/ 15 / 93 and slowly increased after that.

Glucose and sucrose levels for treatment 3 (2 week heat treatment)
dropped below 0.01% and 0.05% respectively on 3/ 1/ 93 but after that wide

variations in samples occurred.

59

Treatment 4 (4 week heat treatment) followed similar trends as the other
treatments with a large variations between samples.

Plots of the curves (Appendix C) fitted to the glucose and sucrose levels
for the four treatments are displayed in Figures 4.10a and 4.10b. The glucose
curves show an increasing slope with increase in heat treatment weeks.
Limited conclusions should be drawn from this data as the correlation
coefficients for these lines are low.
4.3.2.2 Results of Atlantic stored at 125°C

Plots of the glucose and sucrose for treatments 1, 2, 3 and 4 are
displayed in Figures 4.11a, 4.11b, 4.11c and 4.11d. Treatment 1 (0 week heat
treatment) reached a minimum for glucose and sucrose on 2/ 15/ 93. Both
started to rise on 3 / 1/ 93 and the chips went off color 10 weeks later.

Treatment 2 (1 week heat treatment) had glucose and sucrose reach
minimums on 2/ 15/ 93 and both started to rise 2 weeks later. On 4/ 12/ 93 (6
weeks after rise starts) the chips were off color.

Treatment 3 (2 weeks heat treatment) reached minimums on 2/ 15 / 93
for sucrose and on 2 / 28 / 93 for glucose. Sucrose levels rose steadily after
2/ 15 / 93. Glucose levels remained below 001% until 5/ 10 / 93 but chip were
off color on 4/ 12/ 93 (6 weeks later).

Treatment 4 (4 weeks heat treatment) had glucose and sucrose reach
minimums on 2/ 15/ 93 and both started to rise 2 weeks later. On 3/ 28/ 93 (4

weeks after rise starts) the chips were off color.

60

 

 

o/o SWOSG

 

 

 

 

10903/92‘12/0‘3/92'01/26/93'03/25/93'05/20/93o
11/05/92 12/31/92 02/25/93 04/22/93 06/17/93

 

I =- Glucoss A Sucrose — Glucose.r*2=.42-- Sucrose, 1*2=.80J

 

Fig. 4.9a Sugar levels for Atlantic variety with no heat treatment and
100°C holding temperature.

 

 

 

 

 

 

 

0.: 0.04
28.70
I I 15.50
0.3-1 ------------------ ; ..-; -------------------------------------------------- 003
g 02'" """" a """"""""""""""""""""""""""""""""" a" -0.02 3
0° . 0°
A
011-540-442 -------- a ------------------------------- - 0.01
41- _ °
A
1&06/92 ‘ 12/03/92 1 05/20/93 0
11/05/92 12/31/92 02/25/93 0422/93 06/17/93
I =- Glucwe A Sucrose — Gums. 102.42 - - Sucrose. M2212 I

 

Fig. 4.9b Sugar levels for Atlantic variety with 1 week heat treatment at
26.7°C and 100°C holding temperature.

6l

 

0.04

 

’002

°/o Sucrose

0/0 6013056

~0.01

 

 

 

 

130092'12/0592'01/2902 0025-93 F05/20/93 °
11/05/92 12/31/92 022% 0111/22/93 0017/93

 

I = Glucose A Sucrose — Glucose. M2052 -- Sucrose. 192037]

 

Fig. 4.9c Sugar levels for Atlantic variety with 2 week heat treatment at
26.7°C and 100°C holding temperature.

 

0.04

 

b0.03

b0.02

% Glucose

l-0.O1

 

 

 

 

1 05/20/90 °
11/05/92 12131/92 02/2993 0022/33 06/17/93

 

L 0 Glucose A Sucrose — Glucose. 122:.85 - - Sucrose, M2:.83J

 

Fig. 4.9d Sugar levels for Atlantic variety with 4 week heat treatment at
26.7°C and 100°C holding temperature.

0.04
0.03~
8
§ 0.02‘
0
0°
0.01-1
‘ V 11ml' 1 I I U I I IE5 IE! I ‘l mi I 'M1m
1M02/199303/0 03/15/93 04/12/33 05/10/93 06/07/93
F— Owwkm-1week— 2week-- 4weekJ
Fig. 4.10a Glucose late storage season sweetening for Atlantic variety stored
at 100°C.
0.:
9
(D
.0

62

 

 

 

 

 

 

 

 

I ' ‘ T 7 T r t I

 

 

I'

T ' 06/21/93

 

05/10/33

 

02901-93 ' 0331/93 ' '03/29/93
03/1593 04/12/93

I— Oweek----1week—2week-- 4week]

Fig. 4.10b
at 100°C.

06/07/93

Sucrose late storage season sweetening for Atlantic variety stored

63

 

0.311 ------------------------------------------------------------------------------------ «L003

"0.02

°/o Glucose

00.01

 

 

 

 

10903/92’12/03/92r01/23/93503/25/93F05/20/93o
11/05/92 12/31/92 02/25/93 04/22/93 06/17/93

 

I =- Glucose A Sucrose —Glucose,r*2=.73-- Sucrose. 102:.81 I

 

Fig. 4.11a Sugar levels for Atlantic variety with no heat treatment and
125°C holdine temperature.

 

 

 

 

 

 

 

04 7 0.04
26.70 -’
1112-53 12°C /
0.341 ------------------------------------------------------------- 4» -------- 45 ----------- 10.03
.2. .................. - ............................................................... l
g I A t002 (9
0° 6 0°
9
L a
0.11-.4~---a~-=.---é,----A ----------------------------------- .. ----- -0.01
A 2
GD
:3 A A ‘
A
& f I T I I I I o
1 08/92 12/03/92 01/26/93 03/25/93 05/20/93
11/05/92 12/31/92 02/25/93 04/22/93 06/17/93
I =- Glucose A Sucrose — Glucose. r"2=.25 -- Sucrose, M2=.86 I

 

Fig. 4.11b Sugar levels for Atlantic variety with 1 week heat treatment at
26.7°C and 125°C holding temperature.

 

004

 

°/o

~0.01

 

 

 

 

 

12/03/92 ' 1 05/20/93 0
11N582 fiMfifiR 022903 CHQZBG CEHZBG
I =- Glucose A Sucrose — Glucose. M2258 - - Sucrose. Nam

 

Fig. 4.11c Sugar levels for Atlantic variety with 2 week heat treatment at
26.7°C and 125°C holding temperature.

 

 

 

 

 

 

 

0.4 0.04
are
I I15.5C 1250
0.3“ ------ g -------------------------------------------------------------------------- ~ 0.03
A
Q 0.2/rm? ------------- 7' --------------------------------------------- 4 ---------------- ‘ -0.02 5
(.0
0° o\°
A a 1::
a
0.14.50 ----- e ------------------ x --------------------- -0.01
a ‘ a ‘
7", .- ‘
10906/92 T 12/03/92 T 0120/93 T 03/25/93 T 05/20/93 0
11/05/92 12/31/92 0225/93 04/22/93 06/17/93
I =1 Glucose A Sucrose — Glucose.r'\2=.86 -- Sucme. 192:.65 I

 

Fig. 4.11d Sugar levels for Atlantic variety with 4 week heat treatment at
26.7°C and 125°C holding temperature.

65

Plots of the curves fitted to the glucose and sucrose levels for the four
treatments are displayed in Figures 4.12a and 4.12b. The curves of glucose
levels for treatments 1, 2 and 3 are all roughly the same. The glucose for
treatment 4 rises much more sharply. The curves for sucrose follow similar
lines.
4.3.2.3 Discussion of Atlantic at 10.0°C and 125°C

The transfer of the Atlantic tubers from 155°C to 10.0°C had a similar
effect on the sugar levels to that of transferring the Snowden tubers from
155°C to 72°C. This would indicate that the Atlantic is more sensitive to low

temperature sweetening than Snowden.

66

 

% Glucose

 

 

 

 

03/0 was/99 Mia/9d 051
02/15/90 03/15/93 M12196 05/10/99 0907/99

 

F— Oweek----1week— 2week-- 4weekJ

Fig. 4.12a Glucose late storage season sweetening for Atlantic variety stored
at 125°C.

 

0.34

% Sucrose
.0
'Y

0.1-1

 

 

 

 

1 I I I I I I I I I I I I

we ass/24199
02/15/99 03/15/90 04.02/99 05/10/93 cam/93

 

[—Oweek----1week—2week-- 4week]

Fig. 4.12b Sucrose late storage season sweetening for Atlantic variety stored
at 125°C.

67
4.4 FIELD STORAGE BINS

4.4.1 Atlantic vs Snowden in 1990-1991 Storage Season
4.4.1.1 Results 1990-1991

Sucrose and glucose in the Snowden potatoes stored at 72°C and the
Atlantic potatoes stored at 100°C remained low. Both varieties had sucrose
levels below 0.1% and glucose levels below 0.02% for the entire storage period.
All samples during the storage season had acceptable fry color. Data for the
1990-1991 season are listed in Appendix A.
4.4.1.2 Discussion 1990-1991

The Snowden potatoes stored at 72°C appear to respond to storage
management in a manner similar to the Atlantic variety potatoes stored at
10.0°C.

It appears from limited observations that the Snowden variety potatoes
sprouted earlier than did the Atlantic variety potatoes which would indicate
that they should be managed with a faster cooling rate.

4.4.2 Snowden Storage for 1991-1992
4.4.2.1 Results of Cooling Rate Comparison

The set cooling rates of 0.1°C / day (bin 1), 0.3°C/day (bin 2), and
0.5°C/ day (bin 3) resulted in actual cooling rates of 0.09, 0.16, and 027°C / day.
Bins 1 and 2 were located in Bay County, MI and bin 3 was located in
Kalkaska County, MI. Data for the 1991-1992 season are listed in Appendix B.

On January 15 bin 1 was at 83°C and bin 2 was at 55°C. Both bins had

low sugar levels and were acceptable in color. The color and sugars for Bin 3

68

remained at acceptable levels until mid-November, when the pulp
temperatures had lowered to 39°C. After one week at 39°F the chips started
darkening and sugar levels increased.
4.4.2.2 Discussion of Cooling Rates

The differences between the set and actual cooling rates are dependent
on the cooling that outside conditions allow. The set point for the cooling is
calculated from the actual bin temperature, so the maximum cooling per day
will be the set cooling rate. Bin 3 which was cooled at 0.5°C/ day produced
dark colored chips after reaching a holding temperature of 39°C, but the
cooling rate did not appear to adversely effect chip color. The higher cooling
rates did not appear to lead to sugars until temperatures below 72°C were
reached.
4.4.2.3 Results of Sprout Control

Sprout control within the bins was measured by determining the
number of sprouts greater than 0.95 cm (3/ 8 in.) from the 60 tuber sample
taken from each bin. The faster cooling rates in bins 2 and 3 resulted in lower
temperatures and fewer sprouts than in bin 1, which was treated with a sprout
inhibitor (see Figure 4.13).
4.4.2.4 Discussion of Sprout Control

The lower temperatures in bins 2 and 3 regulated sprout growth better
that bin 1 which had the added control of a sprout inhibitor applied on
11 / 20 / 91. The combination of a sprout inhibitor and lower temperatures

should result in a higher level of sprout control.

69

4.4.2.5 Results of Reconditioning

Figure 4.14 displays the chip colors for the four reconditioning
temperatures (83°C, 11.7°C, 155°C, and steps of one week at each of the three
temperatures).
4.4.2.6 Discussion of Reconditioning

Reconditioning at 155°C for 3 weeks resulted in acceptable colored chip
samples. The tubers reconditioned at 117°C produced marginal chips (SFA
color 2). It appears that reconditioning of Snowden variety potatoes will not
normally be necessary, but the feasibility does exist if temperatures near 11°C
are used. Warming to this temperature may result in higher weight losses as
it is difficult to maintain a high relative humidity without getting condensation
on the tubers.
4.4.2.7 Discussion of Bin Exhaust Problems

A problem with the ventilation controllers (fans were off for a number
of days) the first week in December was followed by increases in the glucose
levels in both bins. This may have resulted from low oxygen or high carbon
dioxide concentrations. Figures 4.15a and b show the sugar levels observed as
a result of the problem. Chip color remained marginally acceptable (SFA color
= 2) as glucose levels increased to around 0.02%. On approximately 1/ 18/ 92
the exhaust louver for the building enclosing bins 1 and 2 malfunctioned and
the experiment had to be ended as the control of the ventilation system was
lost. The glucose levels for bins 1 and 2 rose to above 0.05% and 0.09% within

2 weeks and chips became unacceptable. Sucrose levels increased to above

7O

 

(”p 8

3

' .5
Temperature C

 

ll Tuners w/Sprouls > 0.95 cm
ii

 

 

 

 

 

101
-4
5" 1.
————.-—..-.—.—¢ ‘ ' r f ‘:
09919/91 wit/91 01/17/92
10/19/91 12/18/91 @1692

 

F- sum-- aanz-o- ems]

 

Fig. 4.13 Sprout control for samples of 60 tubers, 15 at each level, 1991-
1992. Bin 1 was treated with sprout inhibitor on 11/20/91.

 

 

Chip Color (SFA)

 

 

 

 

 

 

0007/92 04/14/92 04/27/92 04/2'0/92 05/05/92
1* 8.30 --- 11.70 ----15.50 «- 13.341.745.50 ]

 

Fig. 4.14 Color (SFA) of reconditioned potatoes. 1992. Reconditioned at
8.3, 11.7, 155°C and at 1 week steps of 8.3, 11.7 and 155°C.

7

l

Bin 1, holding temperature 7.2 C

 

 

 

 

 

 

 

 

 

 

 

14.04 _
-0.08 "-
12.0‘ _ 2
o . ..\°
3. 10 0 _0 06
8.0-1 -
-0.04 .,\°‘
’_ 6.0“ _
ml
”0.02
2.01 - ~-m-.~- I.
De I I I I I I I I I If I If 0
09/19/91 11/14/91 01/09/92 03/05/92 04/30/92
10/17/91 12/12/91 02m 04/02/92
[— Term. -- Glucoee -- Sucroee I
Fig. 4.15a Bin temperature and sugars for bin 1, 1991-1992.
3h 2, holcfi'lg temperature 5.6 C
16.0 f 0.1
14.01 '
0.08 "-
12.04 _ 3
o q 32
10.0 '0.06
8.0-I ..
-0.04 32’
._ 60'1 ..
g
'0.02
2.01 _ -
O. f If I I I I I r j I I I I r fi fi 0
09/19/91 11/14/91 01/09/92 03/05/92 04/30/92
10/17/91 12/12/91 02/06l92 04/02/92
I — Temp. -- Gimme "- Sucroee I
Fig. 4.15b Bin temperature and sugars for bin 2, 1991-1992.

 

 

72

0.1%. Attempts to recondition the potatoes were unsuccessful. It is assumed
that the rises in glucose were a result of oxygen starvation.
4.4.3 Snowden Storage for 1992-1993
4.4.3.1 Results of Cooling Rates and Storage Temperature

Plots of the temperatures and the tuber sugar levels for the three bins
are displayed in Figures 4.16a, 4.16b and 4.16.c. Bin 1 was cooled to 72°C at a
programmed rate of 0.3°C / day (actual rate 0.17). After 2 weeks at 72°C, no
increases in sugars were noted. After 4 weeks at 7 .2°C, both the glucose and
sucrose had doubled, (to 0.007% and 0.09% on a fresh weight basis). The
glucose levels rose slightly more over the next month and then declined
slightly, but remained below 0.01% for the 4 months they were held at 72°C.
Acceptable color levels were maintained throughout. The sucrose levels
reached 0.1% after 6 weeks and then decreased and remained around 0.075 for
the remaining storage time.

Bin 2 was cooled to 55°C at a set rate of 0.3°C/day (actual rate 0.19).
One week after reaching 55°C, no increases in sugars were noted, glucose was
at 0.003% and sucrose was at 0.05%. Two weeks later, the glucose had risen to
0.08% and the sucrose to 0.1%. After 3 weeks at 55°C, bin 2 was lowered to
5°C over a weeks time, and then held there for 2 weeks. After one week at
5°C, the glucose levels had risen to 0.017% and the chips were marginal in
color (SFA rating 2). The sucrose level was 0.12%. After 2 weeks at 50°C, bin
2 was allowed to warm gradually to 72°C over the next 4 weeks, then held at

that temperature for 8 weeks. The glucose levels during this time were just

73
Bin 1, holding temperature 7.2 C

Pd X 3% .§\o 9.0 X g .5 08—SWJ“ .anaosf
5

 

 

 

          
 

   

 

        

 
       
    

    

 

   
  
   
   

   
   

 

 

 
 

  

 

 

 

 

 

 

 

 

.1311 TIM-1...“. 1
..... 1 1 1
.1 w :
..... ..m .1 . m
1 1 m .1 . 1 . m 1 . m . m 1 W m .
...... . ..-.-.1. 1.- m
..... 1.. - m m.. __ m m. 1.1.. m
1 1 1 ... 1 . s --:.1 ... .1 -. .m 1 W M .w
1 m 1 1 1 . m 1 .1 m a . m 1 1 1 1 1 .
..... 1141..--..m M11. am m..-.....m
m m m m m .m m m m m .m m u u u n .m-

. . . ... . 1 u . . 1 m m m .1 m .
...-..- ..... ......... 1 ..... . m . ...- ..... n--. ---.. m .m1.1 ..... 1 ..... m
W W ... .1 m __ H.- m a M m.. m1
. ..... W. ..... ..... . ....-.qm m..... ..... .- -m m..-1-1.1.11 ..... 1 ..... ...-Em
. . . m 1 ... . m m 1 . 1 ..- m 1 1 1 1 m .1
m n "a": . . m u m m.. . m m .I m . -
..... ..---...- m .1111.-. m 1.. -. m

1 1 n. ..H1 1 m 1 1.. .n m 2 H .. .1.
..... m ..... m H ..... m
1 ...... ...m 1 1 ... _. .11 . H 1 m m 1
m 1 . . 1 1 1 .. _. . . m 1 m: m
m .1 .1 ..... . m . m 1.1 ..... H m .--- .- ..... w ..... ..... m
m w w. W.- m r .w .1 m m m e .... ..m ..m w w w w .... m
0 o 0

i

E
E

1993.

 

[=Glicoee-fl-Sucrose]

 

Temperatures and sugar levels for field research bins. Note:

change in scale and sucrose units for bin 3. 1992

Fig. 4.16

74

above 02% and the sucrose levels declined slowly from 0.1%. Chips were
unacceptable in color with color ratings (SFA) of 2.5-3.0.

After reconditioning for 1.5 weeks at 11°C, the glucose levels dropped
below 0.01% and chips were acceptable (SFA color 1.5).

Bin 3 was cooled to 4.4°C at 0.5°C/day (0.26). As the tubers reached 5
to 6°C, an increase in glucose and sucrose were noted. 4 weeks later sucrose
levels had risen above 0.2%,but remained constant afterwards. Glucose levels
were above 0.04% and continued to rise as they were held in storage.
4.4.3.2 Discussion of 1992-1993 Cooling Rates and Storage Temperatures

The cooling rate of 0.3°C/day and a holding temperature of 72°C
appear to be close to the limits for storing the Snowden variety without
increasing sugars to a level that will adversely affect chip color. A preferred
storage strategy would be one that cools the tubers to a minimum holding
temperature as quickly as possible while maintaining low sugar levels, similar
to the strategy used on bin 1. Bin 1 (holding temperature 72°C) was cooled
allowing a plenum to pile temperature differential of 20°C, which allowed
cooling temperatures as low as 52°C. To prevent the rises in sugars that
occurred in bin 1, the cooling rate should be slowed as the temperature
approaches 72°C and a lower limit (70°C) placed on the cooling air.
4.4.3.3 Results for Reconditioning

On April 21 bin 3 was marketed for seed and samples were warmed to
125°C for reconditioning. Sugar levels declined, but after 4 weeks

reconditioning, chips from the tubers were still unacceptable in color.

75

4.4.3.4 Discussion of Reconditioning

If Snowden potatoes are stored at temperatures where low temperature
sweetening takes place, reconditioning may not be able to remove enough of
the sugars to market the potatoes for processing as chips.
4.4.3.5 Results of Weight Loss in Storage

The weight loss in tubers from bins 1, 2 and 3 were 7.1%, 7.8% and 7.4%
respectively. The humidifiers were in operation more than 97% of the time
during the cool down period. Potatoes in bin 3 were held for one month
longer than bins 1 and 2.
4.4.3.6 Discussion of Weight Loss in Storage

The humidifiers in the field research bin were evidently undersized.
The weight losses (over 7% for all 3 bins) was higher than the target of 3-4%
recommended by Hunter (1986).
4.4.3.7 Results for Sprout Growth

Bins 1 and 2 were treated with MH30 in the field and no other sprout
inhibitor was applied. Sprout growth was minimal for tubers in all bins.
4.4.3.8 Discussion of Sprout Growth

None of the bins were treated with inhibitors after harvest. The cooling

rate of 03°C to 72°C was enough to control sprouting through March.

5. CONCLUSIONS
1. Glucose levels of potatoes provide a quantitative measure of the chip
processing quality.
2. For the Snowden potatoes stored in 1992-1993, a sample with a glucose
level of 0.0075% (fresh weight basis) will have 90% probability of having a
color of 1 or 1.5 (from Figure 4.2). A sample with a glucose level of 0.01% will
have a 90% probability of having a color of 1, 1.5 or 2. Glucose levels for
Atlantic variety potatoes were similar to those of Snowden.
3. Sampling from the top of the bin provides a representative sample of the
bin.
4. Snowden tubers stored at 72°C went "off color" 4 weeks later than the
tubers stored at 10.0°C. The tubers stored at 72°C were warmed to 183°C
after 5 months storage and if left at 72°C may have lasted longer before
sweetening.
5. Heat treatments had a minimal effect on the initiation date of late storage
sweetening. Increasing the length of heat treatment increased the rate at which
sugars rose.
6. Based on biweekly sampling of Snowden tubers from the 1992-1993 storage
season, late storage season sweetening problems can be anticipated by rises in
sugar levels. Increases in glucose can be detected 6 to 8 weeks before chips go
off color and increases in sucrose can be detected 8 weeks before chips go off
color. Additional stresses imposed on potatoes in early storage or during

harvest may increase the rate of sweetening.

76

77

7. The Snowden variety potatoes stored at 72°C respond to storage
management in a manner similar to Atlantic variety potatoes stored at 10°C for
an extended storage season.

8. Faster cooling rates and lower temperatures such as those used for
Snowden can reduce the need for sprout inhibitors in long-term storage and
may eliminate the need for sprout inhibitors in shorter term storage.

9. The Snowden variety can be cooled at faster rates to 9°C than are normally
recommended for processing potatoes in Michigan without causing chip
discoloration or rises in sugar levels-

10. Care should be taken to assure that the difference between pile and
plenum temperatures does not exceed 20°C to prevent excessive moisture loss.
Smaller differences (15°C) may be better if an acceptable cooling rate can be
maintained.

11. Snowden potatoes stored below 4.4°C with low temperature induced
sweetening were successfully reconditioned 1 of the 2 years of the laboratory
study. Reconditioning can be successful if temperatures above 10°C are used
but storage at temperatures below the lower limit for the variety are not

recommended.

6. RECOMMENDATIONS FOR THE STORAGE OF SNOWDEN
Based on past works, observations and data from the 1990-1993 storage years,
and observations from growers in Michigan, recommendations for the storage
of Snowden variety potatoes include (following suberization and
preconditioning):

(a) Cool tubers quickly at a rate of up to 0.3°C/day to a temperature

of 9°C.

(b) Cooling to 72°C should be continued at a slower rate

(0.15°C/ day).

(c) Use air temperatures not less than 7°C.

78

7. SUGGESTIONS FOR FUTURE WORK

Differences between the storage parameters for the Snowden and
previously stored varieties have been noted in this work. The Michigan potato
industry could benefit from information on storage temperatures and cooling
rates that new varieties are able to withstand.

The Michigan Bin Monitoring Program is monitoring a larger number of
bins in its second year with favorable feedback from users. The research bins
located at Bishop Farms in Pinconning, Michigan offer an excellent opportunity
for testing the lower storage temperature limits for the Snowden and other
varieties in an actual bin situation without risking the loss of a large bin of
potatoes. These bins could also be used to monitor the oxygen and carbon
dioxide levels in bins and the effects of limiting the fresh air to potatoes.

Additional data would also be beneficial in evaluating the storability of
bins based on their sugar levels.

On the laboratory scale, the holding of lots of potatoes at different
temperatures and cooling rates until late storage season sweetening leads to
unacceptable sugar levels for chipping, could verify the best storage

temperatures.

79

LIST OF REFERENCES

8. REFERENCES

Allen, E.L., O’Brian, PJ. and Firman, D. 1992. Seed tuber production and
management. In: The Potato Crop. Ed. Harris, P. Chapman and Hall,
London.

ASAE Standards. 1993. Design and management of storages for bulk, fall-crop,
Irish potatoes. EP475-43:587.

Barichello, V., Yada, R.Y., Coffin, RH. and Stanley, D.W. 1990. Low
temperature sweetening in susceptible and resistant potatoes: starch

structure and composition. 1. Food Sci. 55:1054-1059.

Barichello, V., Yada, R.Y., Coffin, RH. and Stanley, D.W. 1990. Respiratory
enzyme activity in low temperature sweetening of susceptible and resistant
potatoes. J. Food Sci. 55:1060—1063.

Boe, A.A., Woodbury, G.W. and Lee, TS. 1974. Respiration studies on
Russet Burbank potato tubers: effects of storage temperature and chemical
treatments. Am. Potato I. 51:355-360.

Burton, W.G., van Es, A. and Hartrnans, KJ. 1992. The physics and
physiology of storage. In: The Potato Crop. Ed. Harris, P. Chapman and
Hall, London.

Burton, W. G. 1974. The oxygen uptake, in air and in 5% Oz, and the carbon
dioxide out, of stored potato tubers. Potato Res. 17:113-37-

Cargill, B. R, Price, K. C. and Forbush, T. D. 1989. Requirements and
recommendations for potato storage in the midwest USA. In: Potato
Storage Technology and Practice, Cargill, B.F., Brook, RC, and Forbush,
T.D., eds. ASAE, St. Joseph, Michigan, USA. pp 271-283.

Claassen, P.A.M., Budde, M.A.W., de Ruyter, HJ., van Calker, M.H. and van
Es, A. 1991. Potential role of pyrophosphate: fructose 6-phosphate
phosphotransferase in carbohydrate metabolism of cold stored tubers of
Solanum tuberosum cv Bintje. Plant Physiol. 95:1243-1249.

Dwelle, RB. 1990. Source/ sink relationships during tuber growth. Am.
Potato I. 67:829-834.

Ehlenfeldt, M.I(., Lopez-Portilla, D.F., Boe, AA. and Johansen, RH. 1990.

Reducing sugar accumulation in progeny families of cold chipping potato
clones. Am. Potato I. 67:83-91.

80

81

Forbush, TD. and Brook, R C. (1993). Influence of airflow on chip potato
storage management. Am. Potato]. 70:869-883.

Gould, WA. 1989. Factors affecting the oil content of potato chips. In:
Chipping Potato Handbook. Snackfood Association, Alexandria, VA. USA.

Hunter, J.H. 1986. Heat of respiration and weight loss in storage. In:
Engineering for potatoes, ASAE, St. Joseph, MI, USA. pp 511-550.

Hughes, ].C- and Fuller, TJ. 1984. Factors influencing the relationships
between reducing sugars and fry colour of potato tubers of cv- Record. J.
Food Technology. 19:455-467.

Iritani, W.M. and Weller, L.D. 1977. Changes in sucrose and reducing sugar
content of Kennebec and Russet Burbank tubers during growth and post
harvest holding temperatures. Am. Potato 1. 54:395-404.

Isherwood, RA. 1976. Mechanism of starch-sugar interconversion in
Solanum tuberosum. Phytochem. 15:33-41.

Isherwood, RA and Burton, WC. 1975. The effect of senescence, handling,
sprouting and chemical sprout suppression upon the respiratory quotient of
stored potato tubers. Potato Res. 18:98-104.

Leszkowiat, M.I., Barichello, V., Yada, R.Y., Coffin, R.H., Lougheed, EC. and
Stanley, D.W. 1990. Contribution of sucrose to nonenzymatic browning in
potato chips. J. Food Sci. 55:279-280.

Lulai, E.C., Sowokinos, IR and Knoper, LA. 1986. Transslucent tissue
defects in Solanum tuberosum L. Plant Physiol. 80:424-428.

Mazza, G. and Siemens, AJ- 1990. Carbon dioxide concentration in
commercial potato storages and its effect on quality of tubers for
processing. Am. Potato]. 67:121-132.

Mazza, G., Hung, I. and Dench, MJ. 1983. Processing/ nutritional quality
changes in potato tubers during growth and long term storage. Can. Inst.
Food Sci. Technol. 1. 16:39-44.

Morrell, S. and ap Rees, T. 1986. Sugar Metabolism in developing tubers of
Solanum tuberosum. Phytochem. 25:1579-1585.

Murata, T. 1972. Sucrose phosphate synthase from various plant origins.
Agricultural Biol. Chem.36:1877-1884.

82

National Potato Council. 1993. Potato Statistical Yearbook, National Potato
Council, Denver, Colorado. USA.

Niederhauser, IS. 1993. International cooperation and the role of the potato
in feeding the World. Am. Potato J. 70:385-403.

Orr, P. 1990. A procedure to correlate color measuring systems using potato
chip samples. Am. Potato J. 67:647-654.

Plissey, ES. 1993. Maintaining tuber health during harvest, storage, and
post-storage handling. In: Potato Health Management. The American
Phytopathological Society, St. Paul, MN. Rowe, RC. ed. 41-54.

Pollock, C]. and ap Rees, T. 1975. Activities of enzymes of sugar metabolism
in cold-stored tubers of Solanum tuberosum.

Pressey, R. 1969. Role of invertase in the accumulation of sugars in cold
stored potatoes. Am. Potato J. 46:292-297.

Pressey, R. 1970- Changes in sucrose synthetase and sucrose phosphate
synthetase activities during storage of potatoes. Am. Potato J. 47:245-251.

Reust, W. and Aerny, J. 1985. Determination of physiological age of potato
tubers with using sucrose, citric and malic acid as indicators. Potato Res.
28:251-261.

Richardson, D.L., Davies, H.V., Ross, H.A. and Mackay, GR. 1990. Invertase
activity and its relation to hexose accumulation in potato tubers. J. Exp.
Botany. 41(222):95-99.

Ross, H.A. and Davies, H.V. 1992. Sucrose metabolism in tubers of potato
(Solanum tuberosum L.). Effects of sink removal and sucrose flux on
sucrose-degrading enzymes. Plant Physiol. 98:287-293.

Santerre, C.R., Cash, J.N. and Chase, R.W. 1986. Influence of cultivar,
harvest-date and soil nitrogen on sucrose, specific gravity and storage
stability of potatoes grown in Michigan. Am. Potato J. 63: 99-110.

Schaper, LA. and Preston, DA. 1989. Requirements and recommendations
for potato storage in the Red River Valley and the North Central Region.
In: Potato Storage Technology and Practice, ASAE, St. Joseph, Michigan,
USA. pp 253-272.

83

Shekhar, V.C. and Iritani, W.M. 1978. Starch to sugar interconversion in

Solanum tuberosum L. I. influence of inorganic ions. Am. Potato J. 55:345-
350.

Sinha, N., Cash, J. and Chase, R. 1990. Activities of PPi and ATP dependent
phosphofructokinases (PFK) in CIPC treated stored potatoes. Personal
Communication.

Snackfood Association Color Chart. Purchased by writing: SFA, 1711 King
Street, Suite One, Alexandria, VA 22314.

Sowokinos, J. 1990. Effect of stress and senescence on carbon partitioning in
stored potatoes. Am Potato J. 67 (12) p. 849-857-

Sowokinos, J. and Preston, D. 1988. Maintenance of potato processing quality
by chemical maturity monitoring (CMM). Minnesota Agricultural
Experiment Station. University of Minnesota, St. Paul, MN. Station
Bulletin 586:1-11.

Sowokinos, J.R., Orr, P.H., Knoper, J.A. and Varns, J.L 1987. Influence of
potato storage and handling stress on sugars, chip quality and integrity of
the starch (amyloplast) membrane. Am. Potato J. 64:213-226.

Sowokinos, JR. and Preiss, J. 1982. Pyrophosphorylases in Solanum tuberosum
L. 111. Purification, physical and catalytic properties of ADPglucose pyro
phosphorylase in potatoes. Plant Physiol. 69:1459-1466.

Sowokinos, JR. 1978. Relation of harvest sucrose to processing maturity and
storage life of potatoes. Am. Potato J. 50:333-334.

Schwirnmer, S., Makower, R.U. and Rorem, ES. 1961. Invertase and
invertase inhibitor in potato. Plant Physiol. 36:313-316.

Thorton, R. 1989. Potato storage requirements and management in the
Pacific Northwest, In: Potato Storage Technology and Practice, ASAE, St.
Joseph, MI, USA.

van Ittersum, M.K., Scholte, K. and Kupers, L.J.P. 1990. A method to assess
cultivar differences in rate of physiological aging of seed tubers. Am.
Potato J. 67:603-613.

Wurr, D.C.E. 1978. Seed tuber production and management. In: The Potato
Crop, P.H. Harris(Ed.) Chapter 8. Chapman and Hall, London.

APPENDICES

JAPPEEHIEX A1

Sugar and temperature for research bins tor 1990-1991 season.

Bin 1 - Snowden, 1990-91, Bishop Farms.
Bin 2 - Atlantic

Height from floor
A = 0.6 m, B = 1.7 m, C = 3.0 m, D = 4.3 m (top)

Blank data were negative measurements for sucrose (measurement errors).

Table A.1 Potato sugar and temperature data for 1990-1991.

 

DATE VARIETY GLUCOSE SUCROSE PULP TEMPERATURE
& LEVEL % % °C °F
10/03/90 Snow_D 0.006 0.045 57 13.9
Atla_D 0.008 0.053 67 19.4
10/10/90 Snow_A 0.010 0.080 59 15.0
Snow_B 0.008 0.069 59 15.0
Snow_C 0.009 0.033 59 15.0
Snow_D 0.010 0.061 60 15.6
Atla_A 0.010 0.078 60 15.6
Atla_B 0.011 0.078 60 15.6
Atla_C 0.008 0.041 61 16.1
Atla_D 0.009 0.074 61 16.1
10/17/90 Snow_D 0.009 0.072 62 16.7
Atla_D 0.009 0.057 62 16.7
10/23/90 Snow_A 0.015 0.012 59 15.0
Snow_B 0.010 0.025 59 15.0
Snow_C 0.009 0.054 59 15.0
Snow_D 0.013 0.032 59 15.0
Atla_A 0.013 0.012 61 16.1
Atla_B 0.012 0.017 61 16.1
Atla_C 0.012 0.006 62 16.7
Atla_D 0.011 0.011 62 16.7
10/31/90 Snow_A 0.008 0.016 59 15.0
Snow_B 0.005 0.014 58 14.4
Snow_C 0.011 0.006 59 15.0
Snow_D 0.008 0.006 59 15.0
Atla_A 0.008 0.012 59 15.0
Atla_B 0.014 0.002 59 15.0
Atla_C 0.006 0.016 59 15.0
Atla_D 0.011 0.010 59 15.0
11/07/90 Snow_A 0.009 59 15.0
Snow_B 0.011 59 15.0
Snow;C 0.014 59 15.0
Snow_D 0.012 59 15.0
Atla_A 0.011 59 15.0
Atla_B 0.010 59 15.0
Atla_C 0.008 0.004 59 15.0
Atla_D 0.009 0.049 59 15.0
11/14/90 Snow_A 0.008 0.082 57 13.9
Snow_B 0.011 0.088 57 13.9
Snow_C 0.012 0.063 57 13.9
Snow_D 0.015 0.076 57 13.9
Atla_A 0.015 0.061 57 13.9
Atla_B 0.013 0.084 57 13.9
Atla_C 0 015 0.080 57 13.9
Atla_D 0.011 0.098 57 13.9

84

85

 

DATE VARIETY GLUCOSE SUCROSE PULP TEMPERATURE
& LEVEL % % °C °F
11/20/90 Snow_A 0.006 0.053 56 13.3
Snow_B 0 006 0.057 56 13.3
Snow_C 0.006 0.061 56 13.3
Snow_D 0.006 0.067 56 13.3
Atla_A 0.008 0.080 56 13.3
Atla_B 0.010 0.063 56 13.3
Atla_C 0 009 0.059 56 13.3
Atla_D 0.006 0.063 56 13.3
11/28/90 Snow_A 0.006 0.047 56 13.3
Snow_B 0.008 0.067 56 13.3
Snow_C 0.008 0.059 56 13.3
Snow_D 0.008 0.051 56 13.3
Atla_A 0.008 0.057 56 13.3
Atla_B 0.008 0.080 56 13.3
Atla_C 0.008 0.057 56 13.3
Atla_D 0.006 0.098 57 13.9
12/04/90 Snow_A 0.006 0.035 53 11.7
Snow_B 0.006 0.029 53 11.7
Snow;C 0.005 0.033 53 11.7
Snow;D 0.008 0.067 53 11.7
Atla_A 0.006 0.043 54 12.2
Atla_B 0.012 0.076 54 12.2
Atla_C 0.006 0.035 54 12.2
Atla_D 0.009 0.051 54 12.2
12/12/90 Snow_A 0.006 0.061 53 11.7
Snow;B 0.006 0.018 53 11.7
Snow_C 0.008 0.057 53 11.7
Snow_D 0.008 0.061 53 11.7
Atla_A 0.009 0.045 53 11.7
Atla_B 0.006 0.039 53 11.7
Atla_C 0.008 0.049 53 11.7
Atla_D 0.004 0.069 53 11.7
12/19/90 Snow_A 0.011 0.041 51.5 10.8
Snow;B 0.017 0.031 51.5 10.8
Snow;C 0.019 0.000 51.5 10.8
Snow;D 0.012 0.016 51.5 10.8
Atla_A 0.009 0.026 52 11.1
Atla_B 0.011 0.049 51.5 10.8
Atla_C 0.012 0.022 51.5 10.8
Atla_D 0.011 0.078 51.5 10.8
12/26/90 Snow;A 0.003 0.055 49.5 9.7
Snow;B 0.012 0.045 49.5 9.7
Snow;C 0.008 0.031 49.5 9.7
Snow_D 0.006 0.002 49.5 9.7
Atla_A 0.010 0.047 51.5 10.8
Atla_B 0.009 0.025 51.5 10.8
Atla_C 0.011 0.027 51.5 10.8
Atla_D 0.011 0.039 52 11.1
01/03/91 Snow;A 0.012 0.008 48 8.9
Snow_B 0.012 0.022 48 8.9
Snow_C 0.011 0.016 48 8.9
Snow;D 0.013 0.041 48 8.9
Atla_A 0.009 0.033 50 10.0
Atla_B 0.009 0.039 50 10.0
Atla_C 0.012 0.022 50 10.0
Atla_D 0.010 0.031 50 10.0

86

 

DATE VARIETY GLUCOSE SUCROSE PULP TEMPERATURE
& LEVEL % % °C °F
01/09/91 Snow_A 0.009 0.074 48.6 9.2
Snow_B 0.009 0.037 47.5 8.6
Snow_C 0.008 0.029 47.5 8.6
Snow_D 0.009 0.067 47.5 8.6
Atla_A 0.008 0.045 50.9 10.5
Atla_B 0.008 0.027 50.4 10.2
Atla_C 0.014 0.029 50.4 10.2
Atla_D 0.010 0.057 50.4 10.2
01/16/91 Snow_A 0.009 0.078 47.1 8.4
Snow_B 0.009 0.090 46 7.8
Snow_C 0.012 0.072 46.4 8.0
Snow_D 0.015 0.078 46.2 7.9
Atla_A 0.011 0.086 50.2 10.1
Atla_B 0.011 0.098 50 10.0
Atla_C 0.009 0.084 50.2 10.1
Atla_D 0.013 0.094 50.4 10.2
01/23/91 Snow_A 0.009 0.076 46.9 8.3
Snow_B 0.010 0.053 45.1 7.3
Snow_C 0.012 0.035 45.1 7.3
Snow_D 0.010 0.041 45.3 7.4
Atla_A 0.010 0.047 50.7 10.4
Atla_B 0.009 0.033 50.5 10.3
Atla_C 0.006 0.047 50.5 10.3
Atla_D 0.006 0.069 50.5 10.3
01/30/91 Snow_A 0.014 0.047 46.9 8.3
Snow_B 0.012 0.027 45 7.2
Snow_C 0.015 0.039 45.1 7.3
Snow_D 0.012 0.020 45.3 7.4
Atla_A 0.010 0.037 50.9 10.5
Atla_B 0.010 0.045 50.4 10.2
Atla_C 0.011 0.039 50.5 10.3
Atla_D 0.009 0.033 50.4 10.2
02/06/91 Snow_A 0.019 0.074 45.8 7.7
Snow_B 0.014 0.094 45.5 7.5
Snow;C 0.016 0.074 45.7 7.6
Snow_D 0.016 0.059 46 7.8
Atla_A 0.017 0.049 50.5 10.3
Atla_B 0.014 0.082 50.4 10.2
Atla_C 0.014 0.076 50.5 10.3
Atla_D 0.019 0.074 50.5 10.3
02/13/91 Snow;A 0.006 0.045 45.5 7.5
Snow_B 0.012 0.045 45.3 7.4
Snow;C 0.010 0.049 45.3 7.4
Snow_D 0.013 0.045 45.3 7.4
Atla_A 0.011 0.031 49.8 9.9
Atla_B 0.010 0.049 49.6 9.8
Atla_C 0.008 0.029 50 10.0
Atla_D 0.012 0.049 49.6 9.8
02/20/91 Snow_A 0.015 0.102 45 7.2
Snow_B 0.013 0.087 44.8 7.1
Snow_C 0.016 0.097 44.8 7.1
Snow_D 0.017 0.096 45.1 7.3
Atla_A 0.012 0.065 48.9 9.4
Atla_B 0.015 0.082 49.5 9.7
Atla_C 0.013 0.061 48.9 9.4
Atla_D 0.013 0.088 48.4 9.1

87

 

DATE VARIETY GLUCOSE SUCROSE PULP TEMPERATURE
& LEVEL % % °C °F
02/27/91 Snow_A 0.011 0 086 45 7.2
Snow_B 0 015 0.110 44.8 7.1
Snow_C 0.013 0.082 44.8 7.1
Snow_D 0.013 0.090 44.6 7.0
Atla_A 0.015 0 059 49.1 9.5
Atla_B 0 015 0.078 50.4 10.2
Atla_C 0.013 0.069 51.1 10.6
Atla_D 0.013 0.057 51.6 10.9
03/06/91 Snow_A 0.016 45.3 7.4
Snow_B 0.015 44.8 7.1
Snow_C 0.017 45.1 7.3
Snow_D 0.019 45.7 7.6
Atla_A 0.017 48.7 9.3
Atla_B 0.017 51.3 10.7
Atla_C 0.015 52 11.1
Atla_D 0.017 53.1 11.7
03/14/91 Snow_A 0 010 0.112 44 6 7.0
Snow_B 0.014 0.131 43 9 6.6
Snow_C 0.017 0.086 44 6 7.0
Snow_D 0.013 0.084 44.6 7.0
Atla_A 0.015 0.035 50 10.0
Atla_B 0.020 0.078 50.9 10.5
Atla_C 0.014 0.059 51.4 10.8
Atla_D 0.016 0 086 52 11.1
03/19/91 Snow_A 0.014 0.092 48 9 9.4
Snow_B 0.013 0.121 46 4 8.0
Snow_C 0.008 0.096 46.4 8.0
Snow_D 0.028 0.082 45 7.2
Atla_A 0.008 0.092 51.1 10.6
Atla_B 0.014 0.090 52.3 11.3
Atla_C 0.012 0.072 52.7 11.5
Atla_D 0.013 0.061 53.2 11.8
03/26/91 Snow;A 0.013 0.080 48.6 9.2
Snow_B 0.016 0.104 48.7 9.3
Snow_C 0.011 0.078 49.3 9.6
Snow_D 0.022 0.063 49.1 9.5
Atla_A 0.017 0.033 51.8 11.0
Atla_B 0.014 0.082 52.5 11.4
Atla_C 0.011 0.055 53.1 11.7
Atla_D 0.013 0.069 52.8 11.6
04/02/91 Snow;A 0.016 0.078 49.1 9.5
Snow_B 0.017 0.116 49.3 9.6
Snow_C 0.012 0.100 49.1 9.5
Snow_D 0.014 0.082 49.1 9.5
Atla_A 0.011 0.053 52.3 11.3
Atla_B 0.019 0.074 52.3 11.3
Atla_C 0.015 0.069 52.5 11.4
Atla_D 0.011 0.059 52.7 11.5
04/09/91 Snow_A 0.015 0.069 53.1 11.7
Snow_B 0.015 0.098 53.2 11.8
Snow;C 0.015 0.094 54.1 12.3
Snow_D 0.017 0.096 51.4 10.8
Atla_A 0.008 0.086 54.5 12.5
Atla_B 0.011 0.082 55.6 13.1
Atla_C 0.013 0.088 54.3 12.4
Atla_D 0.011 0.094 55.9 13.3

.APPiflflIEX B

Sugnr, tunpornturu nnd ngtron color to: roaoarch bins, 1991-1992.

88

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anpmnnnrxzc:

Equations for Figure 4.2 (acceptable lamploa versus glucose level).

All the samples from the research bins were sorted by glucose in
ascending order and divided into intervals. The percent of acceptable

samples/interval
color of 1.5 and
low sugar levels

rose above 0.01%.
in each interval.

were calculated for each interval using an acceptable

2.0 (SEA). The interval width started at 0.001% for

(0.004-0.005%) and was increased as the sugar level
This was necessary to incorporate a number of samples
Each interval had a least 5 samples. The percent of

acceptable samples per interval versus glucose level are plotted in

Figure 4.2 using

the equations below.

Table C.1 Acceptable chips and glucose levels for intervals, 1992-93.
Acceptable Chips in Interval

 

% Glucose'

 

.004
.005
.006
.0075
.0085
.01
.011
.0115
.013
.014
.015
.02
.026

OOOOOOOOOOOOO

SFA 1.5 SFA 2.0
10/10
8/8
7/7 7/7
10/11 11/11
4/5 5/5
4/8
6/7
3/6
4/6
2/9
4/7
0/5 1/10
0/6 0/5

PlotIT output for 1.5 SEA color.

—-- PlotIT Non-Linear Regression Analysis -——

MODEL: Y = B(l)/(l. + 8(2) * EXP(-(B(3) * X + 8(4) * X **2)))

12 Observations used from PlotIT file: B:\COLOR2.SDF

Employing method: MARQUARDT COMPROMISE

Final sum of squares of residuals: 332.3907
Coefficient of Determination: .984
Degrees of Freedom: 8
8(1) Parameter estimate Standard Error
1 372.208200 965.132200
2 4.88292300 17.5425700
3 246.414100 94.5012000
4 —25233.4800 9309.51400

Approximate confidence limits for non-linear model parameters

B( )

DWNHH

Lower Upperf
-1558.05600 2302.47300
-30.2022200 39.9680600

57.4116700 435.416400
—43852.5100 -6614.45300

92

93

Parameter Correlation Matrix

1 2 3 4
1 1.000
2 .996 1.000
3 -.315 -.230 1.000
4 .784 .728 -.826 1.000

WARNING: Extremely high correlation among parameters.
Results may be nonsense. Removal of a parameter from
your model may help alleviate this problem.

A N A L Y S I S O F R E S I D U A L S

Number of positive residuals: 6
Largest positive residual: 8.99739
Number of negative residuals: 6
Largest negative residual: —10.2227
Number of sign runs: 6
Significance of sign runs test: .3810
Average absolute residual: 3.44316
Residual sum of squares: 332.391
Residual mean square: 41.5488
Residual standard deviation: 6.44584
Durbin—Watson statistic: 2.62648
Auto-correlation coefficient: .000

i********t**************itiit'k'k‘kiit************************'k

PlotIT output for 2.0 SPA color.

--- PlotIT Non-Linear Regression Analysis ---

Search terminated after 29 iteration(s)
TOL4 value caused iteration termination!

11 Observations used from PlotIT file: B:\COLOR25.SDF

Employing method: MARQUARDT COMPROMISE

Final sum of squares of residuals: 63.23429
Coefficient of Determination: .997
Degrees of Freedom: 7
8(1) Parameter estimate Standard Error
1 144.370200 29.5670000
2 .745460900 .577491000
3 191.383000 43.3230100
4 -16546.1500 2505.28800

Approximate confidence limits for non-linear model parameters

8(1) Lower Upper
1 85.2361900 203.504200
2 —.409521200 1 90044300
3 104.737000 278.029100
4 -21556.7200 —11535.5700

94

Parameter Correlation Matrix

1 2 3 4
1 1.000
2 .968 1.000
3 .156 .390 1.000
4 .541 .332 -.731 1.000
WARNING: Extremely high correlation among parameters.
Results may be nonsense. Removal of a parameter from

your model may help alleviate this problem.

A N A L Y S I S O F R E S I D U A L S

Number of positive residuals: 4
Largest positive residual: 4.60349
Number of negative residuals: 7
Largest negative residual: -4.99266
Number of sign runs: 6
Significance of sign runs test: .6116
Average absolute residual: 1.77624
Residual sum of squares: 63.2343
Residual mean square: 9.03347
Residual standard deviation: 3.00557
Durbin—Watson statistic: 2.67787
Auto-correlation coefficient: .000

************************************************************

.APPEnflIEX I)

T test for the difference between means of samples st 0.6, 1.7, 3.0 end
4.3 n.ebove the floor in the three research bins for the 1992-1993
storsge season, Snowden variety.

The output of the t test run using SPSS/PC+ Studentware is
presented here. D.1 is the t test for all data and D.2 is for the
trimmed data.

SAMPLING DATES FOR RUNS USING ALL DATA

 

Bins 1 and 2 Bin 3
10/14/92 09/30/92
10/21/92 10/10/92
10/28/92 10/28/92
11/11/92 11/11/92
11/25/92 11/25/92
12/08/92 12/08/92
12/22/92 12/22/92
01/05/93 01/05/93
01/19/93 01/19/93
01/02/93 02/16/93
02/16/93

03/02/93

03/17/93

03/29/93

SAMPLING DATES FOR RUNS USING TRIMMED DATA
10/14/92 09/30/92
10/21/92 10/10/92
10/28/92 10/28/92
11/11/92 11/11/92
11/25/92 11/25/92
12/08/92

12/22/92

01/05/93

01/19/93

95

96

A.1 '1' Test for All Data

NOTE: .A, B, C and D correspond to samples
the bin floor.
BIN 1 GLUCOSI - ALL DATA
A B C D
.00301 .00925 .00237 .00194
.00344 .00430 .00366 .00602
.00366 .00409 .00280 .00323
.00172 .00237 .00129 .00194
.00452 .00323 .00559 .00323
.00301 .00366 .00258 .00344
.00301 .00387 .00301 .00301
.00667 .00710 .00710 .00710
.00559 .00731 .00753 .01290
.00753 .01140 .00882 .00989
.00946 .00495 .01376 .01032
.00731 .00538 .00452 .01204
.00882 .01032 .00538 .01054
.00516 .01075 .00667 .01118
Paired samples t—test: A
B
Variable Number Standard
of Cases Mean Deviation
A 14 .0052 .002
B 14 .0063 .003
(Difference) Standard Standard
Mean Deviation Error Corr.
-.0011 .003 .001 .494
Paired samples t-test: A
C
Variable Number Standard
of Cases Mean Deviation
A 14 .0052 .002
C 14 .0054 .003
(Difference) Standard Standard
Mean Deviation Error Corr.
-.0002 .002 .001 .814
Paired samples t-test: A
D
Variable Number Standard
of Cases Mean Deviation
A 14 .0052 .002
D 14 .0069 .004
(Difference) Standard Standard
Mean Deviation Error Corr.
-.0017 .003 .001 .791

from 0.6, 1.7, 3.0 and 4.3 a above

Standard
Error
.001
.001
2—Tail t Degrees of 2-Tail
Prob. Value Freedom Prob.
.073 —1.43 13 .176
Standard
Error
.001
.001
2—Tail t Degrees of 2—Tail
Prob. Value Freedom Prob.
.000 -.30 13 .770
Standard
Error
.001
.001
2-Tail t Degrees of 2-Tail
Prob. Value Freedom Prob.
.001 -2.41 13 .031

Paired samples t-test:

Variable Number
of Cases
B 14
C 14
(Difference) Standard
Mean Deviation
.0009 .004

Paired samples t-test:

Variable Number
of Cases
B 14
D 14
(Difference) Standard
Mean Deviation
-.0006 .004

Paired samples t-test:

Variable Number
of Cases
C 14
D 14
(Difference) Standard
Mean Deviation
-.0016 .003

97

B
C
Standard Standard
Mean Deviation Error
.0063 .003 .001
.0054 .003 .001
Standard 2—Tail t
Error Corr. Prob. Value
.001 .344 .228 .95
B
D
Standard Standard
Mean Deviation Error
.0063 .003 .001
.0069 .004 .001
Standard 2-Tail t
Error Corr. Prob. Value
.001 .554 .040 —.67
C
D
Standard Standard
Mean Deviation Error
.0054 .003 .001
.0069 .004 .001
Standard 2—Tail t
Error Corr. Prob. Value
.001 .670 .009 -1.87

Degrees of
Freedom

13

Degrees of
Freedom

13

Degrees of
Freedom

13

2—Tai1
Prob.

.361

2-Tai1
Prob.

.513

2-Tail
Prob.

.083

Paired samples t—test:

Variable Number
of Cases
B 14
C 14
(Difference) Standard
Mean Deviation
.0009 .004

Paired samples t-test:

Variable Number
of Cases
8 14
D 14
(Difference) Standard
Mean Deviation
-.0006 .004

Paired samples t-test:

Variable Number
of Cases
C 14
D 14
(Difference) Standard
Mean Deviation
- 0016 .003

97

B
C
Standard
Mean Deviation
.0063 .003
.0054 .003
Standard
Error Corr.
.001 .344
B
D
Standard
Mean Deviation
.0063 .003
.0069 .004
Standard
Error Corr.
.001 .554
C
D
Standard
Mean Deviation
.0054 .003
.0069 .004
Standard
Error Corr.
.001 .670

Standard
Error

.001
.001

2-Tail ' t
Prob. Value

.228 .95

Standard
Error

.001
.001

2-Tail t
Prob. Value

.040 -.67

Standard
Error

.001
.001

2—Tai1 t
Prob. Value

.009 ’1.87

Degrees of
Freedom

13

Degrees of
Freedom

13

Degrees of
Freedom

13

2-Tail
Prob.

.361

2-Tail
Prob.

.513

2-Tail
Prob.

.083

BIN 1 SUCROSE
A

.54610 1
.89225
.81700
.49020
.60415
.69660
.39560
.81485
.91805
.64930
.76110
.40635
.53105
.72885

raw

- ALL DATA

B

.01480
.98685
.98685
.52030
.79550
.84280
.61705
.11370
.20400
.97610
.61920
.44505
.78690
.77185

Paired samples t—test:

Variable Number
of Cases
A 14
B 14
(Difference) Standard
Mean Deviation
-.1735 .155

Paired samples t-test:

Variable Number
of Cases
A 14
C 14
(Difference) Standard
Mean Deviation
.0313 .083

Paired samples t—test:

Variable Number
of Cases
A 14
D 14
(Difference) Standard
Mean Deviation
-.1938 .109

98

C D
.39560 .69445
.73315 1.14165
.82130 .93095
.50095 .70950
.61275 .84280
.64285 .95675
.51385 .61705
.77615 1.03200
.78475 1.03845
.67725 .65360
.83850 .88150
.34830 .88365
.53105 .73960
.63640 .84280
A
B
Standard Standard
Mean Deviation Error
.6608 .171 .046
.8344 .226 .060
Standard 2—Tail t Degrees of
Error Corr. Prob. Value Freedom
.041 .731 .003 —4.20 13
A
C
Standard Standard
Mean Deviation Error
.6608 .171 .046
.6295 .155 .041
Standard I 2-Tail t Degrees of
Error Corr. Prob. Value Freedom
.022 .876 .000 1.41 13
A
D
Standard Standard
Mean Deviation Error
.6608 .171 .046
.8546 .158 .042
Standard 2—Tail t Degrees of
Error Corr. Prob. Value Freedom
.029 .785 .001 -6.67 13

2-Tail

Prob.

.001

2-Tail
Prob.

.181

2-Tai1
Prob.

.000

Paired samples t-test:

Variable Number
of Cases
B 14
C 14
(Difference) Standard
Mean Deviation
.2049 .195

Paired samples t—test:

Variable Number
of Cases
B 14
D 14
(Difference) Standard
Mean Deviation
- 0203 .211

Paired samples t-test:

Variable Number
of Cases
C 14
D 14
(Difference) Standard
Mean Deviation
-.2251 .144

99

B
C
Standard
Mean Deviation
.8344 .226
.6295 .155
Standard !
Error Corr.
.052 .532
B
D
Standard
Mean Deviation
.8344 .226
.8546 .158
Standard
Error Corr.
.057 .439
C
D
Standard
Mean Deviation
.6295 .155
.8546 .158
Standard
Error Corr.
.038 .577

Standard
Error

.060
.041

2-Tail t
Prob. Value

.050 3.94

Standard
Error

.060
.042

2-Tail t
Prob. Value

.117 -.36

Standard
Error

.041
.042

2-Tai1 t
Prob. Value

.031 ~5.85

Degrees of
Freedom

13

Degrees of
Freedom

13

Degrees of
Freedom

13

2-Tail
Prob.

.002

2-Tai1
Prob.

.726

2—Tail
Prob.

.000

BIN 2 GLUCOSE - ALL DATA

100

A B C D
.00237 .00344 .00194 .00366
.00409 .00538 .00280 .00710
.00301 ..00172 .00258 .00237
.00237 .00323 .00280 .00302
.00237 .00452 .00237 .00302
.00280 .00301 .00172 .00280
.00366 .00344 .00215 .00345
.00581 .00667 .00817 .01398
.01419 .01505 .01505 .02473
.01871 .02516 .01892 .01763
.01570 .01591 .01140 .04902
.01226 .02042 .01871 .02946
.00667 .02451 .02967 .02946
.00731 .01505 .00774 .00946
Paired samples t-test: A
B
Variable Number Standard
of Cases Mean Deviation
A 14 .0072 .006
B 14 .0105 .009
(Difference) Standard Standard
Mean Deviation Error Corr.
-.0033 .005 .001 .810
Paired samples t-test: A
C
Variable Number Standard
of Cases Mean Deviation
A 14 .0072 .006
C 14 .0090 .009
(Difference) Standard Standard
Mean Deviation Error Corr.
-.0018 .007 .002 .655
Paired samples t—test: A
D
Variable Number Standard
of Cases Mean Deviation
A 14 .0072 .006
D 14 .0142 .014
(Difference) Standard Standard
Mean Deviation Error Corr.

—.0070 .011 .003 .768

Standard
Error
.002
.002
2-Tai1 t Degrees of 2-Tai1
Prob. Value Freedom Prob.
.000 -2.40 13 .032
Standard
Error
.002
.002
2-Tail t Degrees of 2-Tail
Prob. Value Freedom Prob.
.011 -1.01 13 .332
Standard
Error
.002
.004
2-Tai1 t Degrees of 2-Tai1
Prob. Value Freedom Prob.
.001 —2.49 13 .027

Paired samples t-test:

Variable Number
of Cases
B 14
C 14
(Difference) Standard
Mean Deviation
.0015 .003

Paired samples t-test:

Variable Number
of Cases
B 14
D 14
(Difference) Standard
Mean Deviation
-.0037 .010

Paired samples t-test:

Variable Number
of Cases
C 14
D 14
(Difference) Standard
Mean Deviation
-.0052 .010

B
C
Standard
Mean Deviation
.0105 .009
.0090 .009
Standard
Error Corr.
.001 .933
B
D
Standard
Mean Deviation
.0105 .009
.0142 .014
Standard
Error Corr.
.003 .735
C
D
Standard
Mean Deviation
.0090 .009
.0142 .014
Standard
Error Corr.
.003 .716

Standard
Error

.002
.002

2-Tai1 t
Prob. Value

.000 1.82

Standard
Error

.002
.004

2—Tail t
Prob. Value

.003 -1.41

Standard
Error

.002
.004

2-Tai1 t
Prob. Value

.004 -1.95

Degrees of
Freedom

13

Degrees of
Freedom

13

Degrees of
Freedom

13

2-Tail
Prob.

.092

2—Tai1
Prob.

.183

2-Tail
Prob.

.073

BIN 2 SUCROSE
A

.56545

.89225 1.
.60630
.90515
.72025
.84065
.58695
.15670
.33515
.26420
.99545
.77830
.96965
.84495

.73100
.75465
.67080
.75680
.72670
.86215
1.22120
1.05780
.91160
.58480
.72240
.72885

HHH

.70950

- ALL DATA

B

05995

102

Paired samples t-test:

Variable Number
of Cases
A 14
B 14
(Difference) Standard
Mean Deviation
-.1133 .123

Paired samples t-test:

Variable Number
of Cases
A 14
C 14
(Difference) Standard
Mean Deviation
.1338 .194

Paired samples t—test:

Variable Number
of Cases
A 14
D 14
(Difference) Standard
Mean Deviation
.0020 .186

C D
.63210 .80625
.87290 .90300
.81915 .91805
.52675 .70090
.69875 .73745
.44075 .78475
.35045 .47300
.81485 .03200
.86000 .36955
.89870 .73530
.46440 .87505
.71165 .66005
.73315 .78045
.49020 .38270
A
B
Standard Standard
Mean Deviation Error
.7990 .178 .048
.9124 .232 .062
Standard 2—Tail t Degrees of 2—Tai1
Error Corr. Prob. Value Freedom Prob.
.033 .851 .000 -3.44 13 .004
A
C
Standard Standard
Mean Deviation Error
.7990 .178 .048
.6653 .182 .049
Standard 2—Tai1 t Degrees of 2-Tai1
Error Corr. Prob. Value Freedom Prob.
.052 .421 .134 2.58 13 .023
A
D
Standard Standard
Mean Deviation Error
.7990 .178 .048
.7970 .237 .063
Standard 2—Tail t Degrees of 2-Tail
Error Corr. Prob. Value Freedom Prob.
.050 .629 .016 .04 13 .969

Paired samples t-test:
Variable Number
of Cases
B 14
C 14
(Difference) Standard
Mean Deviation
.2471 .203

Paired samples t-test:

Variable Number
of Cases
B 14
D 14
(Difference) Standard
Mean Deviation
.1153 .211

Paired samples t-test:

Variable Number
of Cases
C 14
D 14
(Difference) Standard
Mean Deviation
-.1318 .192

103

B
C
Standard Standard
Mean Deviation Error
.9124 .232 .062
.6653 .182 .049
Standard 2-Tai1 t
Error Corr. Prob. Value
.054 .542 .045 4.56
B
D
Standard Standard
Mean Deviation Error
.9124 .232 .062
.7970 .237 .063
Standard 2—Tai1 t
Error Corr. Prob. Value
.056 .595 .025 2.05
C
D
Standard Standard
Mean Deviation Error
.6653 .182 .049
.7970 .237 .063
Standard 2-Tail t
Error Corr. Prob. Value
.051 .604 .022 -2.56

Degrees of
Freedom

13

Degrees of
Freedom

13

Degrees of
Freedom

13

2-Tai1
Prob.

.001

2-Tail
Prob.

.061

2—Tai1
Prob.

.024

BIN 3 GLUCOSE -

A

.00387
.00301
.00172
.00839
.02150
.04816
.07203
.09697
.09589
.14641

Paired samples t-test:

Variable

A
B

(Difference)
Mean

-.0065

Paired samples t—test:

Variable

A
C

(Difference)
Mean

.0007

Paired samples t—test:

Variable

A
D

(Difference)
Mean

-.0275

B

.00495
.00409
.00280
.00817
.02086
.05010
.11976
.10127
.10084
.14964

Number
of Cases

10
10

Standard
Deviation

.015

Number
of Cases

10
10

Standard
Deviation

.011

Number
of Cases

10
10

Standard
Deviation

.032

ALL DATA

104

C D
.00430 .00710
.00323 .00581
.00344 .00387
.00667 .00688
.01333 .01806
.02516 .07805
.07117 .10815
.09783 .18340
.11589 .16211
.14985 .19974
A
B
Standard Standard
Mean Deviation Error
.0498 .051 .016
.0562 .056 .018
Standard I 2-Tail t Degrees of 2-Tai1
Error ‘ Corr. Prob. Value Freedom Prob.
.005 .968 .000 -1.40 9 .196
A
C
Standard Standard
Mean Deviation Error
.0498 .051 .016
.0491 .055 .017
Standard 2-Tail t Degrees of 2—Tail
Error Corr. Prob. Value Freedom Prob.
.003 .983 .000 .21 9 .837
A
D
Standard Standard
Mean Deviation Error
.0498 .051 .016
.0773 .080 .025
Standard 2—Tail t Degrees of 2-Tai1
Error Corr. Prob. Value Freedom Prob.
.010 .980 .000 -2.70 9 .024

Paired samples t-test:

Variable Number
of Cases
B . 10
C 10
(Difference) Standard
Mean Deviation
.0072 .018

Paired samples t—test:

Variable Number
of Cases
B 10
D 10
(Difference) Standard
Mean Deviation
—.0211 .032

Paired samples t-test:

Variable Number
of Cases
C 10
D 10
(Difference) Standard
Mean Deviation
-.0282 .030

105

B
C
Standard
Mean Deviation
.0562 .056
.0491 .055
Standard
Error Corr.
.006 .951
B
D
Standard
Mean Deviation
.0562 .056
.0773 .080
Standard
Error Corr.
.010 .948
C
D
Standard
Mean Deviation
.0491 .055
.0773 .080
Standard
Error Corr.
.010 .970

Standard
Error

.018
.017

2-Tai1 t
Prob. Value

.000 1.29

Standard
Error

.018
.025

2-Tai1 t
Prob. Value

.000 -2.05

Standard
Error

.017
.025

2-Tail t
Prob. Value

.000 —2.96

Degrees of
Freedom

9

Degrees of
Freedom

9

Degrees of
Freedom

9

2-Tail
Prob.

.229

2-Tail
Prob.

.071

2-Tail
Prob.

.016

BIN

HHNNHH

3 SUCROSE

A

.00405 1.
.63210
.54395
.96750
.54585
.97585
.60150
.62300
.79525
.99090

NHNB)NH

.75895
.64715
.98900
.61250
.66600
.73050
.27900
.90705
.32200

- ALL DATA
B

06210

HHHNHH

Paired samples t-test:

Variable Number
of Cases
A 10
B 10
(Difference) Standard
Mean Deviation
-.1294 .258

Paired samples t-test:

Variable Number
of Cases
A 10
C 10
(Difference) Standard
Mean Deviation
.2025 .368

Paired samples t-test:

Variable Number
of Cases
A 10
D 10
(Difference) Standard
Mean Deviation
-.2105 .353

106

C D
.90085 1.04060
.59985 .92020
.85570 .63855
.91590 1.15670
.05135 1.64475
.85330 2.75200
.27900 2.38650
.57595 2 38650
.86190 2.60150
.76085 2.25750

A
B
Standard
Mean Deviation
1.5680 .759
1.6974 .794
Standard
Error Corr.
.082 .946
A
C
Standard
Mean Deviation
1.5680 .759
1.3655 .566
Standard
Error Corr.
.116 .886
A
D
Standard
Mean Deviation
1.5680 .759
1.7785 .787
Standard
Error Corr.
.112 .896

Standard
Error
.240
.251
2-Tail t Degrees of 2-Tail
Prob. Value Freedom Prob.
.000 -1.58 9 .148
Standard
Error
.240
.179
2—Tail t Degrees of 2—Tail
Prob. Value Freedom Prob.
.001 1.74 9 .116
Standard
Error
.240
.249
2-Tail t Degrees of 2-Tail
Prob. Value Freedom Prob.
.000 —1.89 9 .092

Paired samples t-test:

Variable Number
of Cases
B 10
C 10
(Difference) Standard
Mean Deviation
.3320 .331

Paired samples t-test:

Variable Number
of Cases
B 10
D 10
(Difference) Standard
Mean Deviation
—.0811 .261

Paired samples t-test:

Variable Number
of Cases
C 10
D 10
(Difference) Standard
Mean Deviation
—.4130 .356

FJ
C)
\l

B
C
Standard Standard
Mean Deviation Error
1.6974 .794 .251
1.3655 .566 .179
Standard ' 2—Tai1 t
rror ( Corr. Prob. Value
.105 ( .936 .000 3.17
B
D
Standard Standard
Mean Deviation Error
1.6974 .794 .251
1.7785 .787 .249
Standard 2-Tai1 t
Error Corr. Prob. Value
.083 .945 .000 -.98
C
D
Standard Standard
Mean Deviation Error
1.3655 .566 .179
1.7785 .787 .249
Standard 2-Tail t
Error Corr. Prob. Value
.113 .912 .000 -3.66

Degrees of
Freedom

9

Degrees of
Freedom

9

Degrees of
Freedom

9

2—Tail
Prob.

.011

2—Tai1
Prob.

.352

2-Tai1
Prob.

.005

D.2 T Test for Trimmed Data

NOTE:
above the bin floor.

BIN 1 GLUCOSE - TRIMMED DATA

108

GA, on, GC and GD correspond to samples from 0.6,

GA GB GC GD
.00301 .00925 .00237 .00194
.00344 .00430 .00366 .00602
.00366 .00409 .00280 .00323
.00172 .00237 .00129 .00194
.00452 .00323 .00559 .00323
.00301 .00366 .00258 .00344
.00301 .00387 .00301 .00301
.00667 .00710 .00710 .00710
.00559 .00731 .00753 .01290
Paired samples t—test: GA
GB
Variable Number Standard Standard
of Cases Mean Deviation Error
GA 9 .0038 .002 .001
GB 9 .0050 .002 .001
(Difference) Standard Standard 2-Tail t
Mean Deviation Error Corr. Prob. Value
-.0012 .002 .001 .480 .191 —1.71
Paired samples t-test: GA
GC
Variable Number Standard Standard
of Cases Mean Deviation Error
GA 9 .0038 .002 .001
GC 9 .0040 .002 .001
(Difference) Standard Standard 2—Tai1 t
Mean Deviation Error Corr. Prob. Value
-.0001 .001 .000 .952 .000 —.48
Paired samples t-test: GA
GD
Variable Number Standard Standard
of Cases Mean Deviation Error
GA 9 .0038 .002 .001
GD 9 .0048 .004 .001
(Difference) Standard Standard 2—Tai1 t
Mean Deviation Error Corr. Prob. Value
- 0009 .003 .001 .718 .030 —1.03

1.7, 3.0 and 4.3 n

Degrees of 2-Tai1
Freedom Prob.

8 .126
Degrees of 2-Tail
Freedom Prob.

8 .645
Degrees of 2-Tai1
Freedom Prob.

8 .334

Paired samples t-test:

Variable Number
of Cases
GB 9
GC 9
(Difference) Standard
Mean Deviation
.0010 .002

Paired samples t-test:

Variable Number
of Cases
GB 9
GD 9
(Difference) Standard
Mean Deviation
.0003 .003

Paired samples t-test:

Variable Number
of Cases
GC 9
GD 9
(Difference) Standard
Mean Deviation
-.0008 .002

109

GB
GC
Standard Standard
Mean Deviation Error
.0050 .002 .001
.0040 .002 .001
Standard 2-Tail t Degrees of
Error Corr. Prob. Value Freedom
.001 .403 .282 1.25 8
GB
GD
Standard Standard
Mean Deviation Error
.0050 .002 .001
.0048 .004 .001
Standard 2—Tail t Degrees of
Error Corr. Prob. Value Freedom
.001 .405 .280 .24 8
GC
GD
Standard Standard
Mean Deviation Error
.0040 .002 .001
.0048 .004 .001
Standard 2-Tail t Degrees of
Error Corr. Prob. Value Freedom
.001 .817 .007 -1.08 8

2-Tai1
Prob.

.247

2-Tail
Prob.

.819

2-Tai1
Prob.

.313

BIN 1 SUCROSI -

TRIMMED DATA

FL

GA GB
.54610 .01480
.89225 .98685
.81700 .98685
.49020 .52030
.60415 .79550
.69660 .84280
.39560 .61705
.81485 1.11370
.91805 1.20400

Paired samples t—test:

Variable Number
of Cases
GA 9
GB 9
(Difference) Standard
Mean Deviation
—.2119 .129

Paired samples t-test:

Variable Number
of Cases
GA 9
GC 9
(Difference) Standard
Mean Deviation
.0437 .092

Paired samples t—test:

Variable Number
of Cases
GA 9
GD 9
(Difference) Standard
Mean Deviation
-.1988 .056

GC GD
.39560 .69445
.73315 .14165
.82130 .93095
.50095 .70950
.61275 .84280
.64285 .95675
.51385 .61705
.77615 1.03200
.78475 1.03845
GA
GB
Standard Standard
Mean Deviation Error
.6861 .187 .062
.8980 .225 .075
Standard 2-Tai1 t Degrees of Z—Tail
Error Corr. Prob. Value Freedom Prob.
.043 .820 .007 -4.94 8 .001
GA
GC
Standard Standard
Mean Deviation Error
.6861 .187 .062
.6424 .149 .050
Standard 2-Tail t Degrees of 2—Tai1
Error Corr. Prob. Value Freedom Prob.
.031 .875 .002 1.43 8 .190
GA
GD
Standard Standard
Mean Deviation Error
.6861 .187 .062
.8848 .180 .060
Standard 2—Tail t Degrees of 2-Tai1
Error Corr. Prob. Value Freedom Prob.
.019 .954 .000 -10.65 8 .000

Paired samples t-test:

Variable Number
of Cases
GB 9
GC 9
(Difference) Standard
Mean Deviation
.2556 .181

Paired samples t-test:

Variable Number
of Cases
GB 9
GD 9
(Difference) Standard
Mean Deviation
.0131 .163

Paired samples t-test:

Variable Number
of Cases
GC 9
GD 9
(Difference) Standard
Mean Deviation
-.2425 .096

111

GB
GC
Standard Standard
Mean Deviation Error
.8980 .225 .075
.6424 .149 .050
Standard 2-Tail t
Error Corr. Prob. Value
.060 .599 .089 4.24
GB
GD
Standard Standard
Mean Deviation Error
.8980 .225 .075
.8848 .180 .060
Standard 2-Tail t
Error Corr. Prob. Value
.054 .696 .037 .24
GC
GD
Standard Standard
Mean Deviation Error
.6424 .149 .050
.8848 .180 .060
Standard Z-Tail t
Error Corr. Prob. Value
.032 .844 .004 —7.54

Degrees of
Freedom

8

Degrees of
Freedom

8

Degrees of
Freedom

8

2-Tai1
Prob.

.003

2—Tail
Prob.

.815

2—Tai1
Prob.

.000

BIN 2 GLUCOSI -

GA

.00237
.00409
.00301
.00237
.00237
.00280
.00366
.00581
.01419

Paired samples t—test:

Variable

GA
GB

(Difference)

Mean

-.0006

Paired samples t—test:

Variable

GA
GC

(Difference)
Mean

.0001

Paired samples t—test:

Variable Number
of Cases
GA 9
GD 9
(Difference) Standard
Mean Deviation
-.0026 .004

GB

.00344
.00538
.00172
.00323
.00452
.00301
.00344
.00667
.01505

Number
of Cases

9
9

Standard
Deviation

.001

Number
of Cases

9
9

Standard
Deviation

.001

TRIMMED DATA

112

GC GD
.00194 .00366
.00280 .00710
.00258 .00237
.00280 .00302
.00237 .00302
.00172 .00280
.00215 .00345
.00817 .01398
.01505 .02473
GA
GB
Standard Standard
Mean Deviation Error
.0045 .004 .001
.0052 .004 .001
Standard 2-Tai1 t Degrees of 2-Tai1
Error Corr. Prob. Value Freedom Prob.
.000 .969 .000 -1.98 8 .084
GA
GC
Standard Standard
Mean Deviation Error
.0045 .004 .001
.0044 .004 .001
Standard 2-Tai1 t Degrees of 2-Tai1
Error Corr. Prob. Value Freedom Prob.
.000 .969 .000 .29 8 .776
GA
GD
Standard Standard
Mean Deviation Error
.0045 .004 .001
.0071 .008 .003
Standard 2-Tai1 t Degrees of 2—Tail
Error Corr. Prob. Value Freedom Prob.
.001 .967 .000 -1.95 8 .087

Paired samples t-test:

Variable Number
of Cases
GB 9
CC 9
(Difference) Standard
Mean Deviation
.0008 .001

Paired samples t-test:

Variable Number
of Cases
GB 9
GD 9
(Difference) Standard
Mean Deviation
-.0020 .004

Paired samples t-test:

Variable Number
of Cases
GC 9
GD 9
(Difference) Standard
Mean Deviation
—.0027 .003

113

GB
GC
Standard
Mean Deviation
.0052 .004
.0044 .004
Standard
Error Corr.
.000 .954
GB
GD
Standard
Mean Deviation
.0052 .004
.0071 .008
Standard
Error Corr.
.001 .968
CC
GD
Standard
Mean Deviation
.0044 .004
.0071 .008
Standard
Error Corr.
.001 .985

Standard
Error

.001
.001

2-Tai1 t
Prob. Value

.000 1.69

Standard
Error

.001
.003

2-Tai1 t
Prob. Value

.000 -1.53

Standard
Error

.001
.003

2-Tail t
Prob. Value

.000 -2.50

Degrees of
Freedom

8

Degrees of
Freedom

8

Degrees of
Freedom

8

2-Tai1
Prob.

.130

2—Tail
Prob.

.164

2-Tai1
Prob.

.037

BIN 2 SUCROSE -

TRIIIID DATA

GA GB
.56545 .70950
.89225 .05995
.73100 .60630
.75465 .90515
.67080 .72025
.75680 .84365
.72670 .58695
.86215 1.15670

1.22120 1.33515

Paired samples t-test:

Variable Number
of Cases
GA 9
GB 9
(Difference) Standard
Mean Deviation
-.0822 .139

Paired samples t-test:

Variable Number
of Cases
GA 9
GC 9
(Difference) Standard
Mean Deviation
.1295 .190

Paired samples t-test:

Variable

GA
GD

(Difference)
Mean

-.0604

Number
of Cases

9
9

Standard
Deviation

.151

GC GD
.63210 .80625
.87290 .90300
.81915 .91805
.52675 .70090
.69875 .73745
.44075 .78475
.35045 .47300
.81485 1.03200
.86000 1.36955
GA
GB
Standard Standard
Mean Deviation Error
.7979 .186 .062
.8801 .258 .086
Standard 2-Tail t Degrees of 2-Tai1
Error Corr. Prob. Value Freedom Prob.
.046 .853 .003 -1.77 8 .115
GA
GC
Standard Standard
Mean Deviation Error
.7979 .186 .062
.6684 .193 .064
Standard 2—Tai1 t Degrees of 2-Tai1
Error Corr. Prob. Value Freedom Prob.
.063 .497 .173 2.05 8 .075
GA
GD
Standard Standard
Mean Deviation Error
.7979 .186 .062
.8583 .248 .083
Standard 2—Tail t Degrees of 2-Tai1
Error Corr. Prob. Value Freedom Prob.
.050 .794 .011 -l.20 8 .266

Paired samples t-test:

Variable Number
of Cases
GB ~ 9
GC 9
(Difference) Standard
Mean Deviation
.2117 .219

Paired samples t-test:

Variable Number
of Cases
GB 9
GD 9
(Difference) Standard
Mean Deviation
.0217 .159

Paired samples t-test:

Variable Number
of Cases
GC 9
GD 9
(Difference) Standard
Mean Deviation
-.1899 .153

115

GB
GC
Standard Standard
Mean Deviation Error
.8801 .258 .086
.6684 .193 .064
Standard 2—Tail t
Error Corr. Prob. Value
.073 .560 .117 2.89
GB
GD
Standard Standard
Mean Deviation Error
.8801 .258 .086
.8583 .248 .083
Standard 2-Tai1 t
Error Corr. Prob. Value
.053 .804 .009 .41
GC
GD
Standard Standard
Mean Deviation Error
.6684 .193 .064
.8583 .248 .083
Standard 2-Tai1 t
Error Corr. Prob. Value
.051 .786 .012 -3.71

Degrees of
Freedom

8

Degrees of
Freedom

8

Degrees of
Freedom

8

2-Tail
Prob.

.020

2-Tail
Prob.

.692

2-Tail
Prob.

.006

BIN 3 GLUCOSE
GA

.00387
.00301
.00172
.00839
.02150

Paired samples t-test:

Variable Number
of Cases
GA 5
GB 5
(Difference) Standard
Mean Deviation
-.0005 .001

Paired samples t-test:

Variable Number
of Cases
GA 5
GC 5
(Difference) Standard
Mean Deviation
.0015 .004

Paired samples t-test:

Variable Number
of Cases
GA 5
GD 5
(Difference) Standard
Mean Deviation
-.0006 .003

- TRIMMED DATA

GB

.00495
.00409
.00280
.00817
.02086

116

GC GD
.00430 .00710
.00323 .00581
.00344 .00387
.00667 .00688
.01333 .01806
GA
GB
Standard Standard
Mean Deviation Error
.0077 .008 .004
.0082 .007 .003
Standard 2—Tail t
Error Corr. Prob. Value
.000 .999 .000 -l.26
GA
GC
Standard Standard
Mean Deviation Error
.0077 .008 .004
.0062 .004 .002
Standard 2-Tail t
Error Corr. Prob. Value
.002 .997 .000 .86
GA
GD
Standard Standard
Mean Deviation Error
.0077 .008 .004
.0083 .006 .002
Standard 2-Tail t
Error Corr. Prob. Value
.001 .975 .005 -.49

Degrees of
Freedom

4

Degrees of
Freedom

4

Degrees of
Freedom

4

2-Tai1

Prob.

.276

2-Tail
Prob.

.439

2-Tai1
Prob.

.651

Paired samples t-test:

Variable Number
of Cases
GB 5
GC 5
(Difference) Standard
Mean Deviation
.0020 .003

Paired samples t-test:

Variable Number
of Cases
GB 5
GD 5
(Difference) Standard
Mean Deviation
-.0002 .002

Paired samples t-test:

Variable Number
of Cases
GC 5
GD 5
(Difference) Standard
Mean Deviation
-.0021 .002

117

GB
GC
Standard Standard
Mean Deviation Error
.0082 .007 .003
.0062 .004 .002
Standard 2-Tai1 t
Error Corr. Prob. Value
.001 .995 .000 1.38
GB
GD
Standard Standard
Mean Deviation Error
.0082 .007 .003
.0083 .006 .002
Standard 2—Tai1 t
Error Corr. Prob. Value
.001 .984 .002 —.18
GC
GD
Standard Standard
Mean Deviation Error
.0062 .004 .002
.0083 .006 .002
Standard 2-Tai1 t
Error Corr. Prob. Value
.001 .965 .008 -2.57

Degrees of
Freedom

4

Degrees of
Freedom

4

Degrees of
Freedom

4

2-Tai1
Prob.

.239

2-Tail
Prob.

.865

2-Tai1
Prob.

.062

BIN 3 SUCROSE - TRINIED DATA

118

GA GB
1.00405 1.06210
.63210 .75895
.54395 .64715
.96750 .98900
1.54585 1.61250

Paired samples t-test:

Variable Number
of Cases
GA 5
GB 5
(Difference) Standard
Mean Deviation
-.0753 .041

Paired samples t-test:

Variable Number
of Cases
GA 5
CC 5
(Difference) Standard
Mean Deviation
.0740 .287

Paired samples t-test:

Variable Number
of Cases
GA 5
GD 5
(Difference) Standard
Mean Deviation
—.1415 .098

GC GD
.90085 1.04060
.59985 .92020
.85570 .63855
.91590 1.15670
.05135 1.64475
GA
GB

Standard

Mean Deviation

.9387 .395

1.0139 .374
Standard

Error Corr.

.018 .996
GA
GC

Standard

Mean Deviation

.9387 .395

.8647 .165
Standard

Error Corr.

.128 .775
GA
GD

Standard
Mean Deviation
.9387 .395
1.0802 .370
Standard
Error Corr.
.044 .969

Standard
Error

.177
.167

2-Tai1 t
Prob. Value

.000 -4.11

Standard
Error

.177
.074

2—Tai1 t
Prob. Value

.124 .58

Standard
Error

.177
.165

2-Tail t
Prob. Value

.007 -3.21

Degrees of
Freedom

4

Degrees of
Freedom

4

2-Tai1
Prob.

.015

2-Tail
Prob.

.595

Degrees of 2-Tai1

Freedom

4

Prob.

.033

Paired samples t-test:

Variable Number
of Cases
GB 5
GC 5
(Difference) Standard
Mean Deviation
.1492 .276

Paired samples t—test:

Variable Number
of Cases
GB 5
GD 5
(Difference) Standard
Mean Deviation
—.0662 .092

Paired samples t-test:

Variable Number
of Cases
GC 5
GD 5
(Difference) Standard
Mean Deviation
-.2154 .295

119

GB
GC
Standard
Mean Deviation
1.0139 .374
.8647 .165
Standard
Error Corr.
.123 .740
GB
GD
Standard
Mean Deviation
1.0139 .374
1.0802 .370
Standard
Error Corr.
.041 .970
CC
GD
Standard
Mean Deviation
.8647 .165
1.0802 .370
Standard
Error Corr.
.132 .632

Standard
Error

.167
.074

2—Tai1 t
Prob. Value

.153 1.21

Standard
Error

.167
.165

2-Tail t
Prob. Value

.006 -1.61

Standard
Error

.074
.165

2-Tail t
Prob. Value

.253 -1.63

Degrees of
Freedom

4

Degrees of
Freedom

4

Degrees of
Freedom

4

2-Tai1
Prob.

.293

2-Tail
Prob.

.182

2-Tail
Prob.

.177

.APPTHUDIXI]!

Curves of late storage season sweetening, 1992-1993.

The sugar data in the 1992-1993 late storage season sweetening
experiment were fit to power curves of the form: sugar level = time‘ + b
starting at the ’1ocal’ minimum leading to late season sweetening. The
resulting coefficients of the resulting curves are listed below in Table
E.1

 

Table E.1 Coefficients for sweetening curves, 1993.
Snowden stored at 7.2%:
Egg of trmt b a r2 Minimum Date
glucose 0 2.65E-16 5.735 0.89 04/12/93
" 1 7.25E-17 5.982 0.78 04/12/93
" 2 5.72E-34 13.278 0.60 04/12/93
” 4 8.03E-11 3.491 0.76 04/12/93
sucrose 0 5.2E-14 5.773 0.97 03/28/93
' 1 1.28E-16 6.922 0.91 03/16/93
" 2 8.56E-13 5.245 0.83 03/28/93
” 4 4.42E-06 2.481 0.79 03/16/93
Snowden stored at 10.0%:
glucose 0 1.8E-15 5.524 0.85 03/16/93
' 1 8.94E-18 6.587 0.85 03/16/93
” 2 1.99E-21 8.301 0.82 03/16/93
' 4 1.41E-16 6.278 0.80 02/15/93
sucrose 0 2.59E-07 2.846 0.92 02/15/93
" 1 9.37E-09 3.536 0.78 03/01/93
“ 2 5.01E—11 4.511 0.86 03/01/93
" 4 2.34E-05 2.180 0.80 02/15/93
Atlantic stored at 10.0%:
glucose 0 9.26E-06 1.428 0.42 02/15/93
' 1 4.99E-09 2.879 0.42 02/15/93
' 2 3.06E-09 3.032 0.53 02/15/93
“ 4 1.19E-12 4.643 0.85 02/15/93
sucrose 0 7.17E—06 2.250 0.80 02/15/93
" 1 9.69E-06 2.224 0.72 02/15/93
" 2 0.000258 1.578 0.32 02/15/93
” 4 9.06E-07 2.720 0.83 02/15/93
Atlantic stored at 12.5%:
glucose 0 8.86E-10 3.083 0.74 02/15/93
” l 4.39E—07 1.914 0.25 02/15/93
" 2 1.56E-08 2.556 0.58 02/15/93
" 4 1.68E-12 4.416 0.87 02/15/93
sucrose 0 3.34E-08 3.312 0.82 02/15/93
' 1 1.61E—09 3.966 0.86 02/15/93
' 2 9.88E-09 3.572 0.93 02/15/93
' 4 1.3E-06 2.686 0.65 02/15/93

 

120