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LIBRARY
Michigan Stat.

University _

 

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This is to certify that the

dissertation entitled

DEVELOPMENT OF A MANUFACTURED POTATO PRODUCT

presented by

MOHAMED AHMED KENAWI

has been accepted towards fulfillment
of the requirements for

PhJ) degreein.E0.0d_S.cien.C£

 

QMVW/ CM/W
/

flajor professor

Date _Ju.n+8/_1.939___

MS U is an Aflinnative Action/Equal Opportunity Institution 0-12771

 

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MSU '8 An Affirmative Action/Equal Opportunity Institution

DEVELOPMENT OF A MANUFACTURED POTATO

PRODUCT
BY

MOHSII‘IOO AhMOd KOIIBWI

A DISSERTATION
Submitted to
Michigan State University
In partial tuiiillment oi the requirements
For the degree at
DOCTOR OF PHILOSOPHY
Department of Food Science and Human Nutrition

1989

LO it) “A (J \(?3 4'

AESIEAQI

DEVELOPMENT OF A MANUFACTURED POTATO

PRODUCT

BY

Mohamed Ahmed Kenawi

Small, extra large and ott- grade"Superlor"and"Atlantlc"potatoes which
normally would not be processed were used in developing a precooked, ready-
to-serve simulated baked potato product.

The potatoes were extruded in a Baker Perkins twin screw extruder.
Following processing, sensory evaluations tor interior color, skin color, texture,
and flavor were done in order to determine the acceptability of the product by
the consumer. Analysis at the sensory evaluation data indicated a high degree
at acceptability tor the factors rated by the panelists.

The potato product was stored trozen tor seven months in two different
packaging materials (2 mil low density polyethylene bags, and 6 mil laminated
retortabie pouchs) and unpackaged. The changes in moisture. content at both
skin and interior, color and texture profile analysis (TPA) were studied during
the storage time. The data showed that the physical deterioration ot the rotate
product was delayed by Individual packaging in moisture resistant polymeric
tllm. _The data also showed no slgnltlcant differences in properties between the
potato product packaged in low density polyethylene and the one packaged in

the laminated retortabie pouch.

DEDICATION

To my lather and the soul at my mother

God bless her.

111

ACKNOWLEDGEMENTS

I would like to express my sincere appreciation to all the people who have
helped me throughout my graduate study. To my major professor. Dr. Jerry N.
Cash, for his guidance, encouragement, and support, for which l'ii always be
grateful. To Or. it. Lockhart. who Improved my knowledge In the area of food
packaging. To Dr. R. Y. Ofoli, for his guidance during my work with the extruder.
To Dr. P. narkakis, who supported my efforts with grace and sophistication. And
to Dr. J. Kelly, tor his serving a member of my guidance committee. A special
thanks to Dr. John Gill for his great guidance during the statistical analysis.

Above all, my special gratitude and appreciation go to my my two sons
ileum and Khaled for their love, understanding and unending support.

iv

TABLE OF CONTENTS

Ella
LIST OF TABLES .......................................................................... vii
LIST OF FIGURES ......................................................................... x
CHAPTER l- Development of A Manufactured Potato Product ................ 1
introduction ........................................................................ 2
Literature Review ................................................................. 4
Material and Methods ...................... . ..................................... 4
1- Manufactured simulated baked potatoes .......................... 4
Retormatlon of the potatoes ......................................... 4
Development of the potato skin .................................... 4
ii- Sensory evaluation of the consumer acceptability .............. 9
A- Sensory method .................. ............................. 9
8- Sample preparation and presentation for sensory
analysis..... ................ . ..... . .................................... 9
C- Judges.. ........................................................... ....9
lil- Statistical analysis ...................................................... 13
Results and Discussion ........................................................ 15
1- Manufactured simulated baked potatoes ......................... 15
il- Sensory evaluation of the consumer as- eptabiiity ............. to

Em
CHAPTER Ii- The Effect of Different Packaging Materials and Storage
Time on Physical Properties of A Manufactured, Frozen

 

Potato Product ........................................................... 27
Introduction ....................................................................... 27
- Packaging requirements ................................................ 27

- The effect of moisture loss during storage - ........ -- --29

- Potato color ........................................ . ....................... 30

- Texture Profile Analysis ......... . ...................................... 30
Material and Methods .......................................................... 33
1- Preparation of the potato product for freezing storage ..... 3

il- Packaging materials .................................................... 33

iii- Determination of Water Vapor Transmission Rate (WVT)....34

iv- Determination of moisture content ............................... 34
V- Determination of color ................................................ 35
Vi- Texture analysis........~ ............................................... 35
- Sample preparation ..... .................................. 36
Vii- Statistical analysis .................................................... 36
Results and Discussion ................... . ................................... 39
Summary and Conclusion ..................................................... 54
References ....................................................................... 56
Appendices.
Appendix -A ................................................................. 61
Appendix -3 ................................................................. as
Appendix -c ............................................ L .................... as
Appendix -D ................................................................. 93

vi

LIST OF TABLES
Table - . Pag e

1 - Th. optimum BXINCOT COROITIOIIS used "I IIIBI'IUTBCILII’II‘IO

simulated baked potato product ............................................... 5
2- Statistical summary of the sensory evaluation ............................. 62

3- Water vapor transmission rate (WVT) of two packaging materials
low density polyethylene (LDPE) and retortabie pouch (R.P) at

two dlffOfOl‘lt COROIIIORI ......................................................... 40

4- Correlation coefficients and confidence intervals for the different

variables changes during the storage period .............................. 52

5- Analysis of variance for moisture of skin In simulated baked potato
product stored unpackaged, in low density polyethylene, or

retortabie pouches ................................................................ 85
6- Analysis of variance for moisture of interior In simulated baked

potato product stored unpackaged, In low density polyethylene,

or retortabie pouches ............................................................ 86

vii

Table

10-

11-

12-

13-

Page
Analysia of variance for color L - value In simulated baked potato
product stored unpackaged, in low density polyethylene, or

retortabie pouches ................................................................ 87

Analysis of variance for color b - value In simulated baked potato
product stored unpackaged, In low density polyethylene, or

retortabie pouches ................................................................ 88

Analysis of variance for firmness in simulated baked potato
product stored unpackaged, in low density polyethylene,

Of TOTOI’IBDI. DOUCHCS ............................................................ 89

Analysis of variance for adhesiveness in simulated baked potato
product stored unpackaged, in low density polyethylene, or

retortabie pouches.. ............................................................. 90

Analysis of variance for cohesiveness In simulated baked potato
product stored unpackaged, in low density polyethylene, or

retortabie pouches. .............................................................. 91
Analysis of variance for gummlnesa In simulated baked potato

product stored unpackaged, in low density polyethylene,

Of I'OIOI'IIDI. DOUCIIOS ........................................................... 92

Changes in the moisture of the skin for the simulated baked potato

product In different packaging materials within time of storage ..... 94

viii

Table

14-

15-

15-

17-

18-

19-

Page

Changes In the interior moisture for the simulated baked potato

product In different packaging materials within time of storage ..... 95

Changes In the color L - value for the simulated baked potato

product III dIHOI'ORI DICKBQIRQ MIIOHBIS within time 0' “0M9. ..... 95

Changes In the color b- value for the simulated baked potato

product in different packaging materials within time of storage ..... 97

Changes In the adhesiveness for the simulated baked potato

product In different packaging materials within time of storage....98

Changes In the firmness for the simulated baked potato product

in different packaging materials within time of storage ............... 99

Changes in the gummlnesa for the simulated baked potato product

in different packaging materials within time of storage ............... 100

ix

LIST OF FIGURES

Figure P899

1- Diagram of MPF-5o DI25 Twin screwe food extruder ..................... 6

2- Schematic outline of the processing of simulated baked potato

product ................................................................................ 7
3- Plastic mold used in reforming the potato product ........................ 8
4- Reformed potato product without skin ....................................... 1o
5- Reformed potato product with skin ........................................... 11
8- Final condition of the coooked reformed potato product ............... 12
7- Sensory evaluation questionnaire ............................................ 14
8- Sensory evaluation for color of reformed potato product .............. 17
9- Sensory evaluation for texture of reformed potato product ........... 18
1 0- Sensory evaluation for flavor of reformed potato product ............. 19

‘I 1' 3.0.0” WBIUBIIOII TOI' OVOI‘B" ICCODIBI'IC. Of I'OTOI'IROG DOING

product .............................................................................. 21

Figure Page

1 2- Composite sensory evaluation for color of reformed potato

product...... ........................................................................ 22

Q

1 3- COMPOSI‘IO 89080” BVBIUBIIOII IOI' IOXIUI’B Oi ”TONI!“ DOIBIO

prOduc‘OIOCQOOOOOOOIIOOOOOOO00.0.00...I.......OOIOIOOICOOOO0.00.00.00.00 OOOOOOOOOOOOO 23

1 4- Composite sensory evaluation for flavor of reformed potato

p'OductOO ....... ... ....... O ................ ... .................................... .0024

1 5- Composite sensory evaluation for overall acceptance of reformed

potato product................. ........ ............. ....... . ........... 25

1 6- Typical first and second bite compression curve for instron

Universal Machine............................ ...... . ........... . ...... .. ......... 37

1 7- Change of the skin moisture content for the simulated baked potato

product In different packaging material during frozen storage......41
1 8- Change of the Interior moisture content for the simulated baked
potato product In different packaging material during frozen

“°r‘a..l..00.00....0.000.000.0000... ........ ......IOCOOOCOIIO ........... ...... ...... 42

1 9- Change of the color L-vaiue for the simulated baked potato

product in different packaging material during frozen storage......44

xi

Figure Page

20-

21-

22-

23-

24-

25-

26-.

27-

CIIBI‘IQO OT "10 COIOI' b-VBIUO IOI' the SIMUIB‘IOO baked DOIBTO

product In differentipackaging material during frozen storage... ..... 46 .

Change of the firmness for the simulated baked potato product

In different packaging material during frozen storage .................. 47

Change of the cohesiveness for the simulated baked potato

product In different packaging material during frozen storage ...... 48

Change of the adhesiveness for the simulated baked potato

product in different packaging material during frozen storage ...... 49

Change of the gummlnesa for the simulated baked potato

product in different packaging material during frozen storage ...... 50

Change of the skin moisture content for the simulated baked

potato product during frozen storage ...................................... 64

Change of the Internal moisture content for the unpackaged

simulated. baked potato product during frozen storage. ............. 65
Change of the Internal moisture content for the simulated baked

potato product in low density polyethylene package during frozen

"orage. 000000000000 ... ....... ... IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII O ............... 68

xii

Figure Page

28- Change of the Internal moisture content for the simulated baked

potato product in retortabie pouch during frozen storage ........... 67

29- Change of color L-vaiue for the unpackaged simulated baked

potato product during frozen storage ..................................... 68

30- Change of color L-value for the simulated baked potato product In

low density polyethylene package during frozen storage..... ...... 69

31 - Change of color L-value for the simulated baked potato product in

retortabie pouch during frozen storage ........ . ......................... 70

32- Change of color b-vaiue for the unpackaged simulated baked potat

product during frozen storage...... ......................... ...... ..71

33- Change of color b-vaiue for the simulated baked potato product in

low density polyethylene package during frozen storage ..... ......72

34- Change of color b-value for the simulated baked potato product In

TBIOHBDIO DOUCII dUI‘II‘Ifl II'OZBI'I STOI’BQB ............. . .................... 73

35- Change of firmness for the unpackaged simulated baked potato

preduct du'lno 'rozen "oraQGCOCCCOOOOIOC......OOIOOOOOIIOCCOIO......OOOCCC74

36- Change of firmness for the simulated baked potato product in low

density polyethylene package during frozen storage................75

xiv

Figure P890
37- Change of firmness for the simulated baked potato product In

retortabie pouch during frozen storage .................................. 76

38- Change of cohesiveness for the simulated baked potato product

during frozen storage.... ..................................................... 77

39- Change Of the IdI'IOSIVOIIOSS for the Ui'lpICIthOd simulated baked

potato product during frozen storage ..................................... 78

40- Change of the adhesiveness for the simulated baked potato
product in low density polyethylene package during frozen

storage ............................................................................. 79

41- Change of tho adhesiveness IOI' III. sIl‘lItilltOd baked potato

product In retortabie pouch during frozen storage .................... 80

42- Change of the gummlnesa for the unpackaged simulated baked

DOTITO PI'OGIICI dlflll‘lfl "01.0 storage..... ................................ 81

43- Change of the gummlnesa for the simulated baked potato product

In low density polyethylene package during frozen storage ........ 82

44- Change of the gummlnesa for the simulated baked potato product

in retortabie pouch during frozen storage ............................... 83

XV

W

Potatoes ( Soianum tuberosum L. j are considered one of the most
important vegetables In the world In both total production and nutritional value.
Among the total potato crop produced in the United States, a large percentage
Is commercially processed ( Davis et al., 1983). Michigan potato production Is an
economically Important segment of the state's agriculture. Every year a portion
of the potato crop ls graded Into small, extra large or off-grade classes. Some of
these tubers may find acceptance In certain types of processed products but
this Is usually minimal. Since this part of the crop represents significant
quantities of raw product, economics dictate that these potatoes be utilized In
some other manner. However, without processing alternatives, a majority find
their way into thefresh market and this results In lowering the consumer's
perception of Michigan potato quality, with attendant losses In sales and
revenue. Therefore, It is Important that a new processed product be developed
which can utilize that portion of the potato crop which Is not suited for use In
presently established processed products.

The primary objective of this study was to develop a precooked, ready-to-
serve potato product which could be used as a simulated baked potan with a
unltonn size and shape and serve as a substitute In restaurants or Institutional

TOOO SONIC. OpOTBIIORS.

W

Extrusion technology has been applied to a number of food products.
Harperl1981) Indicates that, the early food extruders were used by the meat
Industry and In the manufacturing of macaroni. General Mills, Inc. used the
extruder to produce ready-to-eat cereals, which were cooked and formed
continuously with a one-step process . Presently the extruder ls being used to
produce a variety of food products like precooked modified starches, ready-to-
eat cereals, snack foods, breeding substitutes, beverages bases, soft-moist
and dry pet food, confections, and soups.

Extruded foods and cereals, which are primarily starch, represent an
Important and expanding area in food processing. The extruder plays several
Important functions In the processing of these foods. These functions Include
cooking and gelatlnizatlon of the starch, giving the food a desired shape and
texture. Jadhav et al.(1976) studied the relationship between some
physicochemlcal properties of dehydrated potato granules and their stability for
extruded French fries. They found that they could produce good quality
extruded French fries by using these granules with a mixture of binders such as
guar gum, stabilized high amyiose corn starch. crosslinked pregelatlnlzed corn
starch, and hydroxypropyI-methylcelluiose.

Extrusion processed potato snacks. which are generally made from
dehydrated potatoes, have captured large segments of the market. These
potato snacks have been made by rehydratlng the potato flakes followed by
extruding, sheeting, stamping, and deep frying (Mega and Cohen, 1978).

Nonaka et al. (1978) produced fabricated French fries by extruding a mixture

containing 90% dehydrated potato. These fabricated French fries were a
competitor to the fries made from raw potatoes because their composition could
be controlled, elemlnatlng variations of palatablllty, quality and trying time.

The extruder can also be used In studying changes In the physical
properties of starch during processing. Kim and l-lamdy (1987) used high
pressure extrusion In order to evaluate the degradation of potato starch, and
they found that the significant decreases in viscosth of starch solutions were
due to depoiymerlzatlon of the starch molecules Into smaller fractions.

Texture of cooked potatoes Is considered to be one of the most
Important quality factors for consumer acceptance (Davis et al., 1983). Kuhn et
al. (1959) found that the processing quality of cooked potato tubers was usually
judged by the texture. It Is generally agreed that good quallty Dolled, mashed,
and baked potatoes should have a meaty texture.

Ruth and Work (1981) used sensory panel methods to evaluate the

quality of baked potatoes grown In Ontario with others grown In Maine and they
found that tubers of the Ontario variety were considered less desirable for table
stock due to the low meallness and grayness of flesh. The textural quality of
potatoes has been studied by many Investigators (Tourneau et al., 1962 ;
Bettelhelm and Sterling, 1954).
Leung et al.(1983), evaluated the texture of cooked potatoes by sensory
evaluation, and texture profile analysis (TPA). They found that there is a
correlation between the hardness by the sensory evaluation and the hardness
by the TPA.

Davis and Dixon (1976) evaluated potato texture by using taste and
appearance of tubers. They found a high correlation between the results
obtained by the two methods and they concluded that visual ratings can provide '

a relatively precise method of judging meallness In potato tubers.

W

W

Peeled, diced potatoes of the cuitlvars ”Superior" and "Atlantic" were
steamed at atmospheric pressure for three minutes prior .to processing. This
steaming was carried on In order to:

Capture free water by the starch In the tubers.

Inactivate oxidatlve enzymes.

Partially cook the potatoes prior to extrusion.

The steamed potatoes were then cooled in cold water and 7% by weight of non-
fat dry milk powder was added to the cooled steamed potatoes to act as a
binding agent. The mixture then was fed Into a Baker Perkins twin screw
extruder. The general operating parameters for the extruder had been
previously detennlned but the final specific operating conditions were obtained
by trial and error during several preliminary runs In the extruder . Table 1
describes the optimum conditions used In operating the extruder. These
Include Items such as the setting and actual temperature for each zone, feed
set, screw speed, and the final product temperature. Figure 1 shows a diagram
of the twin screw extruder and its different zones. Figure 2 outlines the
processing steps for the remanufactured simulated baked potatoes.

Warns.

The product coming from the extruder die (residence time 45 see.) was
filled through a hole into a plastic mold (Fig.3) that looked like an average,
oblong potato.

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The potatoes in the mold were frozen in order to facilitate removing the

product from the plastic molds, then dipped In a mixture of 200 gm wheat flour,

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Fig.3. Plastic mold used In reforming the potato product.

300 ml cold water, 500 mg glycine and 500 mg dextrose which was used to form
a skin for the potatoes.

The frozen reformed potatoes were dipped In the better for 1-2 minutes to make
sure that a thin layer of the batter covered each individual potato, then the
potatoes were frozen again before deep frying In corn oil at 360°F for 3 minutes
to develop the skin texture and color (the crust developed after one minute,
whereas the preferable color was obtained after two more minutes). Figures 4,
5, and 6 show the reformed potato product after being removed from the plastic
mold, after being covered with flour batter, and after being deep fried
respectevely. After trying, the potatoes were stored In the freezer before
sensory evaluation and packaging took place.

WWW

Mammalian.

Sensory evaluation for the color (skin and interior), texture, and flavor
were done on the simulated baked potatoes shortly after processing In order to
determine consumer acceptability. A non-numerical hedonlc scale which
ranged from excellent to extremely poor was used for sensory evaluation

(Larmond,1977.).

 

The frozen simulated baked potatoes were cooked In a microwave oven
for three minutes, then they stood for one minute outside the even before they
were presented to the panelist. Each panelist examined one sample, and was
provided with salt to be used if desired.

was.

Slxty- four judges, graduate and undergraduate students from different
departments, at Michigan State University participated In this test. Each judge

was presented with one sample and was asked to examine the color of the skin

10

 

Fig.4. Reformed potato product without skin.

11

 

Fig.5. Reformed potato product with skin.

12

 

Fig.6. Final condition of the coooked reformed potato product.

13

and the Interior, the texture, and flavor for the reformed potato product. Judges
were encouraged to provide their comments.
After collecting the data and prior to analysis, the descriptors were assigned the
value 1 (extremely poor), 2 (very poor), 3 (poor), 4 (below fair), 5 (fair), 6 (above
fair), 7 (good), 8 (very good), 9 (excellent). Figure 7 shows a typical example of
the questionnaire which was provided to the judges to give their response in
evaluating the product. '
Wham
The standard error of a mean (SEM ), the mean, the variance, and the percentage of ear
character ( color, texture, and flavor) and for overall rating were calculated In order to

analyze the sensory evaluation and to get an Idea of consumer acceptabllity.(Glil,1981)

14

SENSORY ANALYSIS BALLOT
W

PRODUCT: SIMULATED BAKED POTATOES DATE: / I

PLEASE RATE THE SAMPLE YOU ARE PRESENTED ACCORDING TO THE
FOLLOWING ATTRIBUTES; COLOR, TEXTURE, FLAVOR. PLACE AN X BESIDE
THE DISCRIPTOR WHICH BEST EXEMPLIFIES YOUR REACTION TO THE

PRODUCT .

COLOR TEXTURE FLAVOR

SKIN INTEROR
EXCELLENT ..........................................................................................
VERY cooo........................... ......................... . .....................................
coon ...................................................................................................
ABOVEFAIR ......... . ...... . ................... . ........................................... . .........
FAIR .....................................................................................................
BELOWFAIR ..................... . ....................................................................
POOR ....... .
VERYPOOR ...........................................................................................
EXTREMELYPOOR... ..............................................................................

COMMENTS ABOUT OTHER CHARACTERISTICS OF THESE SAMPLES:

Fig.7. Sensory evaluation questionnaire.

mm

Figure 2 shows a flow diagram for the processing steps of the simulated
baked potatoes. Prior to extrusion, the raw potatoes were steamed for 3
minutes In order to gelatlnlze the starch and thus capture free water. This is
Important In preventing or controlling " water feedback " during operation of
the extruder.

Stearnlng for 3 minutes was found to be the optimum time required to
solve that problem. Steaming for a shorter time was not sufficient and
steaming for a longer time produced a mushy texture In the product which was
not desirable.

To bind the extruded potato particles together, 7% by weight of non-fat
dry milk powder was used as a binding agent, as well as to increase the
nutritional value, to Improve the color, and to enhance the flavor of the final
product.

High temperatures in the extruder, gave the product an undesirable
texture while lower temperatures left the product with an unacceptable taste.

Figures 3 and 4 show two photographs of the plastic mold which was
used In reforming the extruded potatoes, and the frozen reformed potatoes
after being taken out of the mold.

During the deep-frying of the coated potato product two things take
place:-

1- FOI'II‘IatIOI'l Of the hard Skll'l dIil’Ihg the first ITIII‘IUte of deep frying.

15

16

2- Developing the desirable color through Malilard reaction during the
second two minutes. These changes can be seen In Figs. (5 and 6), which
show two photographs of the coated and the coated deep fat-fried potato
product and we realize that the coating gave the product a smooth appearance
while the deep fat-frying developed and enhanced the appearance.

WWW

Processing quality of the simulated baked potatoes was evaluated by a
sensory panel In order to examine the acceptability of the product by the
' consumer.

One of the most Important parameters affecting the quality Is the flavor.
According to Hadzlyev 1982, the term "flavor” denotes a complex sensation
Including odor or aroma, mouth feel, texture, and even appearance.

Figure 10, represents the relationship between the percentage of the
judges and their evaluations for the flavor of the simulated potato product. It
Is evident that most of panelists' evaluations ( 82%) are between the values
excellent to fair.

Color evaluation for the potato skin and interior Is given In Fig.8 which
shows the relationship between the percentage of the panelists and their
evaluation. The majority of the panelists evaluated the samples as excellent to
fair (92% and 83%), and only a few of them (8% and 17%) evaluated the skin
and the Interior respectively as below that. This shows that the color of the
new product was accepted by most of the judges.

The relationship between the percentage of the judges and their
evaluation of texture Is represented In Fig.9. Whereas most of the panelists'
evaluations were between the values very good and fair, few of them went
above the value very good or below the value fair. However, none of the

panelists' evaluations were very poor or extremely poor.

°/o Panelists

17

COLOR
.o W

 

I Skin Ex . ancellent: .
g. I . V.G=Vez'y Good.
(E "“m' c =Good.

 
   
   
 
  

 

 

3° A.r=Abova raiz'.
r stair.
BJ’saalow Fair.
P 8200:.

20 '

V. P-Vez-y Poor .
S . P-Extz'mly Poor .

 

  

10

 

o . . . . . . "L - .
Ex. V.G G A.F F B.F P V.P E.P
Panelist evaluations

Fig.8. Sensory evaluation for color of reformed potato
product.

 

% Panelists

18

TEXTURE

 

”’1

3° Ex.-Excellent.

.Givery Good.
aGood.

.F=Above Fair.
Irair.

.FIBelow fair.
aPoor.

.P=Vbry Poor.

.Palxtrenaly Poor.

20

wouunun<

 

 

10

 

 

Ex. V.G G A.F F B.F P V.P E.P

Panelist evaluations

Fig.9. Sensory evaluation for texture of reformed potato
product

19

FLAVOR

 

 

    

 

 

 

   
  

 

 

 

 

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Fig.1o. Sensory evaluation for flavor of reformed

product.

20

In conclusion from the above figures It Is obvious that the majority of
the panelists agreed on the acceptability of all the features of the new
product. This conclusion ls summed up In Fig.11, which represents the overall
acceptance of the product.

In the comments from the panelists, those who either disliked the
product or graded It poorly, did so because of several reasons:-

1- They were unfamiliar with the baked potatoes due to their place of

origin.

2- They do not like plain potatoes and they all commented that If the
potato product had been topped with butter, sour cream, or some
other topping, their responses would have been much better.

Figures 12, 13, 14, and 15, represent the percentage of the panelists
and their responses toward the color (skin, and Interior), the texture, the
flavor, and overall acceptance. When we devlded the panelists' responses
Into two groups, the first group which Includes the responses between the
value excellent to the value fair ( Ex - F ), and the second group which
contains the responses between the values below fair to extremely poor (B.F -
- E.P ), and plotted that against the percentage of the panelists the previous
figures were obtained. From those figures we could conclude that over 80%
and sometimes over 90% of the panelists their responses were In the first
group which Is ( Ex-F ), and less than 20% of them their responses were In
the second group which is ( B.F-E.P ), and this Is In definite agreement with
the other conclusion.

Table 2 ( Appendix A), represents the statistical analysis of the sensory
evaluation for the remanufactured potato product . The numerical average of

the acceptability of each character examined ( color, texture, flavor, and

21

OVERALL ACCEPTANCE

 

 

 

 

 

 

 

823:3. .x.

Panelist evaluations

OVBI’BII ICCBDIBRCO OI I'OTOITI'IOO

Fig.11. Sensory evaluation for

potato product.

% panelists

22

 

 

 

    
 

 

  

 

 

 

 

COLOR
100
r
F
m r-
’ xx . Incellent .
' r stair.
60 - B.rbnelow tair.
E.Ptlxtrenaly Poor.
40
2D
0

Panelists responses

Fig.12. Composite sensory evaluation for color of reformed
potatoproduct.

% panelists

100

 

Flg.1 3.

23

TEXTURE

 

 

 

n.3axce11ent.
l' Irair.
BJ’IBalow fair.
E.P-Extremely Poor.

    
    
 

 

 

Ex. F B.F__ E.P

Panelist responses

Composite sensory evaluation for texture of reformed
potato product.

% panelists

24

 

 

    
    
 
 

 

 

 

 

 

FLAVOR
100
. ‘ xx.-l:xcellent.
80 P ‘ f Ifair.
B.Faelotr fair.
W E.Psnxtranely Poor.
so .-
40 l-
W
W
m r-
Ex._ F B.F_ E.P
Panelist responses

Fig.14. Composite sensory evaluation for flavor of reformed
potato product.

 

 

 

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26

OVOI‘BII BCCBPIBRCO) Wthh IS shown In the IBOIO IS DBSBO Oil the SCBIO OI 1=

extremely poor to 9- excellent .

1111892119119!

The quality of food products Is fragile, because of susceptibility to
spoilage, loss of nutrients and changes In color, flavor, odor, and texure. The
period between the manufacture of a food product and Its retail purchase ls
defined as” shelf life”. The shelf life of a food product varies according to the
type of product and! Its storage conditions.

Storage studies are part of each product development program whether It
Involves a new product, a product Improvement, or simply a change In type or
specification of an Ingredient. In this study the potato product was packaged In
two different moisture barrier materials, and stored in a freezer for a long term In
order to determine some of the changes that could take place which might

affect the product shelf life. (IFT Expert Panel,1974).

W

Plastic materials are used extensively for packaging. In general they
provide more protection , and visibility of the product than some other materials
like paper. The availability of these materials In different forms and the great

II‘I'IpfOVOI'flOI'It ll'l IhOII’ TOSISIBI'ICO lO I'l'lOIStLIfO, water vapor "BRSI'IIISSIOI'I, BRO

27

28

grease, and easy closure has led to widespread use of plastics for foods (Paine,
1983).

Polyethylene film Is one of the largest volume commercial polymeric
materials and Its structural characterization ls of great Interest ( Mathlouthl,
1986). It Is more strongly hydrophobic than many other organic films, so water
vapor penetrates If to a limited degree. This particular property, along with Its
high rate of gas permeability, are of considerable value In the packaging of
Items which require a low moisture loss, while maintaining the ability to transmit
significant amounts of oxygen or carbon dioxide (. Seed, 1989).

The principal flim materials used for food bags are low and high density
polyethylene. Low density polyethylene (LDPE) Is the more widely used of
these two because of Its flexibility and cost. It can be extruded Into film, blown
Into bottles, Injection molded into closures and dispensers of all sorts,
extruded as a coating on paper, aluminium foil or cellulose film, and made Into
large tanks and other containers by rotational casting ( Paine, 1983).

The permeation of water vapor through a packaging material has a great
deal of influence on the preservation of food quality. Mathlouthl, (1986) and
Paine (1983) reported that a good frozen food package must withstand low
temperatures, provide a barrier to transmission of water vapor, must be water-
reslstant, non-toxic and Impart no odor or flavor to the food.

Ben-Yehoshua (1979) reported that wrapping lemon In high density
polyethylene film (HDPE) reduced weight loss and slowed softening. Also, he
found that seal-packaging (shrink wrapping) of fruit In 0.01 mm HDPE film
markedly .‘duced the loss of weight In oranges stored under normal conditions

for shipping or storing.

29

Risse et al. (1984) and Miller and Risse (1986) found that by using a
combination of shrink-wrapping, Irradiation and refrigeration, deterioration of
produce was slowed considerably.

Desk at al. (1987) studied extending the shelf life of fresh sweet corn by
shrink-wrapping and refrigeration. It was shown that wrapping essentially
eliminated moisture loss and mulled In extended shelf life.

Anzueto and Rlzvl (1985) and Ben-Yehoshua (1985) found that the
shrink-wrapping of fruits and vegetables In plastic films appear to be simple and
Inexpensive alternatives. Also, they found that shrink-wrapped produce had an

extended shelf life of several weeks, even at ambient temperature.

WW

Texture and color are two Important criteria used In the U.S. grading
standards for frozen French fries (Talburt and Smith, 1975). There are many
factors which are related to the changes In texture and color. One of these
factors Is the moisture loss during storage of the product. Dehydration can be
caused by moisture vapor, produced by variations of temperature created within
the package, escaping through the walls or Ineffective seals of the package.
This moisture loss dehydrates the surface of the frozen food which causes
freezer burn. The dehydrated surface layer can be very thin, but may affect the
appearance and ultimate saleablllty of the product (Paine, 1983).

Sych et ai.(1987) studied the effect of Initial moisture content and
storage relative humidity on textural changes of layer cakes during storage, and
found that there was an Inverse relations:.ip between the Initial moisture
content and the cakes' firmness. Also, they reported that the loss of the
product moisture content throughout the storage period can be minimized by

Increasing the storage relative humidity.

30

Will:

Color and discoloration of foods are Important quality attributes In
marketing. Color Is often used to determine the ripeness of fruit, but often ls
used to give some Idea about the changes which are taking place during
processing or long term storage (Pomeranz, 1987).

Color Is a very readily dlscemlble attribute for estimating quality of potato
products. The optimum color for steamed, boiled, baked, or mashed potatoes ls
creamy white. For fried potato products, a highly unlfonn golden crust ls
considered optimum. Off-color Is usually associated with after-cooking
darkening of fresh tubers or with the undesirable darkening from the non-
enzymatlc browning reaction that may occur during frying or dehydration. For
optimum color, low reducing sugar content ls desirable, especially for chips and
French fries (Zaehrlnger et al., 1967).

Johnson (1957) and Lyman (1961) found that potato chips from tubers of
high specific gravity were lighter In color than chips from tubers of low specific
gravity. Lujan and Smith, (1964) found a positive relationship between specific
gravity and after- cooking darkening of potatoes.

Wallets:

Texture, appearance, and flavor are three major components of food
acceptability (Bourne, 1978) which may be susceptible to deterioration during
long-term storage. The degree of deterioration and Its Influence on consumer
acceptability determine the shelf life of a product .

Texture quality Is considered to be one of the most Important single
factors In detennlnlng suitability of potatoes for processing and It Is also a very

good Indicator of the deterioration taking place during storage of the product.

31

The Texture Profile Analysis ( TPA) technique Is a very Important tool In
terms of giving a good understanding of the textural properties of foods. It can
be used to follow changes In different textural parameters as a result of
changes taking place In forrnulatlon and processing as well as during storage of
foods (Bourne, 1978). Schmidt and Ahmed (1971) used the TPA method to
study the effect of peeling methods on textural properties of cooked potatoes.

Although the texture of cooked potatoes ls usually evaluated by sensory
methods, Zaehrlnger et al. (1962) reported that In certain types of research It Is
necessary to evaluate the texture of a large number of samples, a situation that
raises certain problems. If the samples are scored at a single sitting, the judges
may experience sensory fatigue. On the other hand, If the samples are judged
over an extended period, Interpretation of the descriptive terms may fluctuate
with time and with the ability of the judges to recall. Therefore, Instrumental
methods are used to evaluate textural properties In order to obtain Information
related to the manner In which the consumer Identifies these properties
(Shame, 1973).

The lnstron Universal Testing Machine can be meaningfully employed to
evaluate the textural properties of food (Shame, 1973). The first attempt to
apply the lnstron Universal Machine to objective TPA was done by Bourne
(1968). He determined TPA parameters of hardness, brittleness, cohesiveness,
elasticity, chewlness and gummlnesa by Interpreting first and second bite
compression curves according to the procedure outlined by Friedman of al.
(1963).

Adhesiveness Is defined as the work necessary to overcome the
attractive forces between the surface of the food and the surface of other

materials with which the food comes In contact such as the tongue, the teeth,

32

etc. (Sherman, 1969). It Is calculated from the negative force area for the first
blte In the TPA curve.

Cohesiveness ls defined as the ratio of the positive force area during the
second compression to that during the first compression, and It represents the
degree to which the sample deforms before It ruptures (Bourne, 1978,
Montejano et al., 1985).

Hardness ls defined as the peak force during the first compression cycle
" first bite”, whereas gummlnesa ls defined as the enerilv .requlred to
disintegrate a semisolid food product to a state ready for swallowing (Shaman,
1969) and calculated as the product of hardness and cohesiveness.

Sherman (1969) reported that the relative Importance of cohesion and
adhesion depends on their magnitude. When adhesion force Is larger than the
cohesion force, part of the food will adhere to the teeth. On the other hand, the
particles of the food will not be retained on the teeth when the cohesion forces
are larger than the adhesion forces. ..

Following the pioneering work of Bourne et al. (1966) and Bourne (1968)
the instron Universal Testing Machine has been widely used In evaluation of
textural properties of food (Shame, 1973). Henry et al., (1971) used the lnstron
to measure and to develop the analysis of the adhesiveness for seml- solid

tOOOS.

W

Wits—WWW

The potato product was divided Into three groups. One group was packa
god in low density polyethylene bags, the second group was packaged In
laminated retortabie pouches, while the last group was left without packaging as
a control. All of the three groups were stored under freezing condition for

SOVOI'I II‘IOIIthS.

W

Two different packaging materials were used In this study. The first one
was commercial low density polyethylene ( LDPE) 2 mil bags from Packaging
Concepts and Design, a division of Bader Bag Co. Madison Heights, Michigan.
The second packaging material was 6 mil Laminated retortabie pouches PP I Al .
fall I PET ‘( Polypropylene I Aluminum tell I Polyethyleneterphthalate) from
American Can Co. (Material Number if 125 44-050). The materials were cut to
form small pouches with dimensions of 6" x 8" and heat-sealed on three sides
by using a variable speed roller sealer (manufactured by the ARO
CORPORATION, Model e PN F 100-1000) at a temperature of 4oo°F and speed
20%. The potato products were packaged Individually, then the bags were
sealed In such a way as to minimize the space between product and package to
avoid the problem of freezer burn, which could result from the loss of moisture

from the product during storage.

33

34

W

The water vapor transmission rate (WV‘I') of the test packages at ambient
condition and In the freezer was determined as described In ASTM.E-96 method
as follows:- .

Ten bags of each material were used In this study. About 35 g. of
desiccant was put In each bag, heat-sealed and weighed. Five bags of each
material were stored at ambient condition ( In the lab.), while the rest of the
bags were stored In the freezer. The storage period was 14 days. After that the
bags were weighed again (every two days) to calculate the amount of water
vapor absorbed by the deslcant.

The following equation was used to calculate the water vapor transmission rate:-

WVTaW/(AXt)

where:-
W: Weight gain or loss In g.,
A: Exposed area of the package material ( total area of the
two sides of bag) In m2.,
1 s Time, during which gain or loss was observed in hours.,

We Rate of water vapor transmission In g / m2. day.

MW
To monitor the extent of potato product dehydration throughout long-
tenn storage, moisture detennlnatlons (wet basis) for the skin and the Interior

were carried out In triplicate, and performed Initially and on a monthly basis.

35

About 5.00 g of the potato product which was stored frozen In LDPE
bags, In retortabie pouches, and without package (control) were dried overnight

at 80°C in a vacuum oven (25 Inch Hg).

W

The color of the potato product crumb was determined using a Color
Difference Meter, Model 25 ( Hunter Associated Lab., Inc., Fairfax, Virginia).
Two samples of each treatment ( LDPE, R.P, and control) were taken out of the
freezer, and the package removed. The samples were microwaved for 2.5 min.
at full power, then were held for 5 min. at room temperature.

After removing the crust of the samples of each treatment they were
placed In a half-filled glass cell ( diameter 10 cm, height 5 cm) on the aperture of
an Inverted Hunter photoreceptor unit. The sample and glass cell were then

COVOI’OO With B DIBCK CVllI'IOBI' to [8606. stray light. The ll‘lStI‘Ul‘l‘lOflt W88
standardized prior to analysis, using a standard White tlie (L: 92.35, aLa -1.2,

DLa 0.5).

Wis:

Texture Protlle Analysis (TPA) was used to evaluate force compression
curves obtained on potato samples with the lnstron Universal Testing Machine (
Model 4202). A 5.00 cm diameter plunger, attached to the instron, compressed
the potato samples twice In sequence. The lnstron was operated with a
crosshead speed of 10 cm/mln., chart speed of 38 cm/mln., distance travel of
the plunger 1.5 cm In the sample, and a full scale load of 20.00 N.

These operating conditions were used to determine the hardness or
firmness, cohesiveness, adhesiveness, and gummlnesa of the potato samples

during storage .

36

W

Two samples of each packaging and control treatment were used to
determine the TPA Initially and five times during the storage period ( 2nd, 4th,
5th, 6th, and 7th month of storage). The potato samples were microwaved for
2.5 min., then held at room temperature for 5 min. before shaping Into cubes of
8 cm3 volume. The textural values reported are averages of 8 measurements.

A generalized lnstron TPA curve ls shown In Fig.16. The curve shows
sharp peaks at the end of each compression due to the fact that the
compression speed of the lnstron ls constant and there Is abrupt reversal of
direction at the end of each line. As shown In the figure , the height of the flrst
compression measured the resistance of the potato product crumb to the
penetrating plunger and represented the hardness of the potato crumb.

The negative force area for the first compression (A3) is known as the
adhesiveness. Aheslveness Is measured In Instrument units of the negative
peak obtained as the plunger withdraws from the sample In the first cycle. This
area Is said to represents the work necessary to pull the compression plunger
away from the sample.

The ratio of the positive force areas (Ag/A1) under the first and the second
peaks represents the cohesiveness of the potato interior. These areas are said
to represent the work done In each cycle and the ratio ls said to be a direct
function of the work done In overcoming the Internal bonds of the material.

Gummlness W88 CBlCUlBtOO ff'Ol'l‘I til. pI'OOUCt Of lIBf'OflOSS BRO COHOSIVOROSB.

Wm
Two factor analysis of variance (ANOVA) was carried out on the
observations from each variable measured ( 96 moisture of skin and Interior,

COIOI’ CRBRQBS, BRO TOX‘IUI’O Pl’OfllO ARBIVSIS ). The fBCtOI'S IRCIUOOO "I. "If”

FORCE

37

 

 

A‘l

 

 

 

 

 

“V7

TIME

Fig.16. Typical first and second bite compression curves for lnstron
Universal Machine.

ii = Hardness or Firinness. A2IA1 = Cohesiveness.
A3 = Adhesiveness.

38

treatments ( packaged In LDPE, packaged In R.P, and non-packaged) , and the
storage periods. This permitted the calculation of the variance due to treatment
effects, storage effects, their interactions, I
and the. estimation of experimental error. Comparison of treatment differences
was done by Tukey's Honestly Significant Difference test (HSD). The correlation -
coefficients (CORR) procedure was used to establish the relationship between

the variables obtained by the three treatments.

3W

Packaging of produce in polymeric films Is a common technique designed
to prevent moisture loss, to protect against mechanical damage, and to provide
better appearance. Proper selection of packaging films can favorably alter any
undesirable changes taking place during long-term storage, resulting in an
extended shelf life and Improved quality ( Heing and Gilbert, 1975).

Table 3 shows the water vapor transmission rate (WVT) values for the two
packaging materials, low density polyethylene (LDPE), and laminated retortabie
pouch (E.P), under two different conditions ( ambient and freezing condition).
The laminated film appeared to allow less moisture to permeate than the LDPE
film under both conditions. Also, the differences in the WVT values were
affected not only by the packaging materials or the thickness of the films, but
they were affected also by the conditions during the experiment (temperature
and relative humidity).

As expected, packaged potatoes which were held at freezing conditions
for seven months tended to show slower rates of moisture content loss for skin
and Interior than their nonpackaged counterparts (Figs. 17 and 18).

Although the percentage of moisture content loss of both packaged and
nonpackaged potato product during the storage was observed, it was obvious
that the trend of moisture loss in the packaged product was negligible
compared to that in the control (unpackaged).

The percentage loss of the moisture content in the skin and the interior
for the nonpackaged potatoes was 22% and 8% respectively. However, for the

9018‘008 DICKOQOC In LDPE and E.P and SIOIOd at "IO same conditions '0!

39

40

Table -3. Water vapor transmission rate (WVT) of two packaging
materials low density polyethylene (LDPE) and retortabie
pouch (B.F) at two different conditions.

 

 

Packaging Conditions WVT
material - g/mz. day
LDPE Ambient 1.430
Freezer 0.055
R.P , Ambient 0.042

Freezer 0.022

 

% MOISTURE CONTENT
o 3 3 8 3 3 8 3 8 8

41

 

100

 

 

 

 

 

 

0 1 2 3 4 5 6 7 8
STORAGE TIME ( MONTHS )

Fig.17. Change of the skin moisture content for the simulated
baked potato product in different packaging material
during frozen storage.

WIO a Unpackaged.
LDPE a Packaged in low density polyethylene.
E.P a Packaged in laminated retortabie pouch.

% MOISTURE CONTENT

42

 

 

 

 

 

 

 

l l l l l I

o 1 2 3 4 5 e 7
STORAGE TIME (MONTHS )

Fig.18. Change of the interior moisture content for the
simulated baked potato product In different
packaging material during frozen storage.

WIO = Unpackaged.
LDPE = Packaged in low density polyethylene.
E.P a Packaged in laminated retortabie pouch.

43

seven months the moisture loss In the skin was 7% and 4% and for the Interior
was 2% for both packaging materials and this ldlcates that the Individual film
packaging reduced the moisture loss. This may be explained by the effect of
packaging materials which retarded the moisture vapor permeation from the
inside to the outside atmosphere.

Table 6 (Appendix C) shows that the differences between the changes In
the moisture content In the Interior for the potato product packaged In two
different packaging materials were not significant, and this Is In agreement with
the data, in table 14 (Appendix D) which Indicates that there are no significant
differences (pa0.05) between the two packaged treatments.

A slight decline In color (L-value) was observed for Individually packaged
and nonpackaged potato products under all storage periods studied. Figure 19
shows that nonpackaged products had a higher level of decline than the
packaged products. However, the color (b-vaiue) of both the packaged and
nonpackaged potato product stored under the same conditions and the same
period did not appear to be significantly affected (Fig. 20).

Loss of moisture content from the potato product during the storage
period was also manifested In the increase of the firmness value. This behavior
can be attributed to the dehydration effect due to moisture loss during the
storage period. The results of the correlation coefficient indicate that the trend
of firmness agrees with the trend of moisture loss In all treatments because
when the food material loses water, its particles stick together and this will
cause resistance to the penetration of the lnstron plunger, which translates as
an Increase In firmness value.

Firmness is affected by the packaging treatment, and storage time.
However, there was almost no difference In this value for the packaged potato

product '0' "I. "I'M "V. months 0‘ MOMQO. Th0 dlflOl‘OI‘ICOO “8"“ to "107.88.

‘

HUNTER COLOR (L-VALU E)

44

 

(Elmo amps-m»

III/I’ll!!!

 

 

I’ll/IIIIIIIIIIIII

 

0 2 3 4 5 6 7
STORAGE TIME (MONTHS)

Fig.19. Change of the color L-value for the simulated

baked potato product In different packaging
material during frozen storage.

-.- Unpackaged.
= Packaged in low density polyethylene.
Packaged In laminated retortabie pouch.

 

45

after that, due to differences In the water vapor transmission rate between the
LDPE and the E.P. Potato products packaged In LDPE bags were firmer than
the product packaged In E.P.

Generally speaking, the firmness value was higher for the unpackaged potato
product and lower for the packaged product. This Is In agreement with the trend
of moisture loss (Figs. 21 and 35-37 Appendix 3).

Changes in the cohesiveness value of the potato product followed the
same pattern in all treatments studied ( packaged and nonpackaged) during the
storage period (Fig.22). The cohesiveness value gradually Increased and
reached the maximum at the fifth month of storage then it declined slightly
again.

Figure 23 represents the relationship between the adhesslon value and
storage time for the packaged and nonpackaged potato product. The trend of
changes in this relationship is similar to the trend of changes In cohesion. The
figure shows that the adhesion value gradually Increased and reached Its
maximum between fifth and the sixth month of storage then started to decline.
At all storage times the adhesiveness value of the nonpackaged product was
lower than the value of the packaged one.

Based on TPA data, (Fig.24 and FIgs.34-M Appendix B) the unpackaged
potato product (control) was the gummlest . However, there were no significant
differences In the cohesiveness values for the three treatments at any time of
storage (Fig.38 Appendix B).

The results obtained showed that the nonpackaged potato product had
the higher gummlnesa values than the packaged potatoes, may have been
because of the higher flnnness values which were used in calculating

HUNTER COLOR ( b-VALUE)

46

 

25 B WIO E LDPE I R.P

 

l|ill[IlllHIIHIIllHHIIIIHHIHHIHHHH~
\

 

 

 

 

 

0 I 2 I 3 4 5 6 7
STORAGE 11ME (MONTH)

Fig.20. Change of the'coior b-value for the simulated
baked potato product in different packaging
material during frozen storage.

WIO s Unpackaged.
LDPE = Packaged In low density polyethylene.
Fi.P = Packaged in laminated retortabie pouch.

FIRMNESS (N)

47

 

 

 

 

 

 

 

Fig.21. Change of the firmness for the simulated
baked potato product In different packaging
material during frozen storage.

WIO = Unpackaged.
LDPE = Packaged In low density polyethylene.
E.P a Packaged In la'ilnated retortabie pouch.

COHESIVENESS

48

 

0.20

 

 

0.1 0

 

 

 

0.00

4 so
)

Fig.22. Change of the cohesiveness for the simulated
baked potato product In different packaging
material during frozen storage.

WIO = Unpackaged.
LDPE a Packaged In low density polyethylene.
= Packaged In laminated retortabie pouch.

ADHESIVENESS (N.mm / min.)

49

 

IIIIIEI
E
R

 

 

    

 

lllllliillllllllllHlliim

 

4 5 5 7
STORAGE TIME ( MONTHS )

Fig.23. Change of the adhesiveness for the simulated
baked potato product In different packaging
material during frozen Storage.

WIO a Unpackaged.
LDPE a Packaged In low density polyethylene.
l'-I.P = Packaged In laminated retortabie pouch.

GUMMINESS (N)

50

 

WIO

AlllllL'J

 

  

 

 

 

HHHHIHiHIHHHHlHllthllHlHl

 

7

STORAGE TIME ( MONTHS )

Flg.24.Change of the gummlnesa for the simulated
baked potato product In different packaging
material during frozen storage.

WIO -.- Unpackaged.
LDPE : Packaged In low density polyethylene.
R.P‘ = Packaged In laminated retortabie pouch.

51

Interaction of treatments and storage time Imply that the rate of loss of
moisture (Fig. 17) and the rate of Increase of firmness and gummlness (Figs. 21
and 24) are not the same for the three groups (packaged and unpackaged).
Obviously, the rate of loss of moisture and the rate of Increase In firmness and
gummlness Is much greater In the unpackaged treatment, and the main effects
of treatments and storage times are Irrelevant. The rate of changes of moisture,
firmness and gummlness for the- unpackaged treatment are greater than the
packaged treatments from the second month of storage to the end of the
storage period.

Figure 19 shows that there is no Interaction between treatments and
storage time up to the third month of storage, then the rate of change of color
L-vaiue for the unpackaged product started to decline rapidly. However, In the
relationship between color b-vaiue and storage time (Fig.20) the trend of
changes for the three treatments is parrailel during the first three months of
storage and after that the rate of change for the unpackaged treatment began to
differ from the other two packaged treatments.

Correlations between TPA parameters, moisture content for skin and
Interior, and color values (L,b) are summarized in Table 4.

Flrrnness has a positive correlation with gummlness, whereas the color b-value
has a positive correlation to all the TPA parameters. The moisture content (skin
and interior) also had a positive correlation with adhesiveness, cohesiveness,
and color L-vaiue. However, the color L-value had a negative correlation with
the other parameters except the adhesiveness. The correlation between the
moisture content of skin and interior Is also poa;:ive. Table 5-12 (Appendix C)
show the analysis of variance (ANOVA) of the variables studied for the
simulated baked potato product (packaged and nonpackaged). These tables

show "I. "GOTHIC!" OTTOCIS, SIOI'OOO OTTO“. SI'Id "I. Il'ltOfICflOfl DOING.“

52

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53

treatment and storage. Also, they show slgnltlcance at these effects, as well as
level of slgnltlcance. However, Tables 13-19 (Appendlx D) represent the
changes of the variables atudlad ( molsture, color, and TPA values) for the
packaged and the nonpackaged potato product wlthln the tlme of storage.
These tables show the mean tor each treatment at each tlme of storage and the
standard error ot the mean SEM, as well as the level of slgnltlcanca.

Generally speaklng, the quallty of potato product whlch was packaged ln
LDPE bags dld not appear to be recognlzably dltterent from the quallty of
potatoes whlch were packaged ln lamlnated retortable pouches, but slgnltlcant
dltterences were seen between the packaged and unpackaged product.

The bottom llne ls that the physlcal deterloratlon ot the manufactured
potato product ln trozen storage was delayed by Indlvldual packaglng ln
molsture reslstant polymerlc tllms (2 mll LDPE, and 6 mll lamlnated retortable
pouch). The nonpackaged potato product held under the same storage
condltlons, obvlously lost slgnltlcsnt amounts of molsture especlally trom the
skln, and galned hlgher hardness values compared to the packaged ones.

The dltterencss In propertles between the potato product packaged In
LDPE and the one packaged In the lamlnated retortable pouch were not
slgnltlcant (pso.05). Therefore, the use ol 2 mll low denslty polyethylene as a
packaglng materlal tor the manutactured baked potato product Is very sultable
from the economlcal polnt ot vlew, as well as, the standpolnt ot quallty

I'I'IIIMOI'IOI'ICO.

W

In any given year, a portion of the potato. crop will be graded Into small,
extra large or off-grade classes. Some of these tubers may find acceptance in
certain types of processed products but this Is usually minimal. Therefore, It Is
Imperative that new processed products be developed which can utilize that
portion of the potato crop which Is not suited for use In presently established
processed products.

it Is feasible to use the twin screw extruder to manufacture the simulated
baked potato product. Prior to extruding, steaming of the potatoes, and adding
binding agent were done In order to prevent any problem during extruder
operation and to bInd the extruded potato particles together. Plastic molds
were used In reforming the extruded potatoes, then slmulated skin was
developed for the final frozen product.

Sensory analyses were performed on the product to determine consumer
acceptability. Discriminatory and preference tests Indicated that a majority of
panelists (over 80% and sometimes over 90%) rated the product as excellent to
fair for color, texture, flavor, and overall acceptance.

Stability of the product during frozen storage for seven months In two
different packaging materials (low density polyethylene and laminated retortable
pouch) was studied. The data showed that physical deterloratlon, such as
moisture content for the skin, and the Interior, color, texture profile analysis
(TPA) of the manufactured potato product In frozen storage, was delayed by
Indlvldual packaging in moisture resistant polymerlc films. The correlation

between TPA and "I. COIOI' b-VSIUO W88 DOSItIVO, 88 W88 "IO II‘IOIMUI'O COI‘ItOlfl,

54

55

adhesiveness, cohesiveness and the color L-value. However, the color L-vaiue
had a negative correlation with the other parameters except adhesiveness.

The differences In properties (moisture content, color, TPA values)
between the potato product packaged In LDPE and the one packaged In the

laminated retortable pouch were not significant (p=o.05).

W

American Society for Testing and Materials. E-96, 1987. Standard Test Method
for Water Vapor Transmission of Materials. Annual book of ASTM
standards. Voi.15.09, Philadelphia, PA.

Anzuets, 6.3., and Rlzi, S.S.H. 1985. Individual packaging of apples for shelf
life extension. J.Food Sci. 50:897.

Association of Official Analytical Chemists. 1985. Official Methods of Analysis.
13") Ed. Published by A.O.A.C. Washington, o.c.

Bannore, M.A.1937. Potato meallness and changes in softness on cooking .
Food Res. 2:377.

Ben-Yehoshua, S., Kobiler, l., and Shapiro, B. 1979. Some physiological
effects of delaying deterioration of citrus fruit by Indlvldual seal packaglng
In high density polyethylene film. J. Amer. Soc. Hort. Sci. 104 (6) : 868-
872.

Ben-Yehoshua, S., Kobiler, I., and Shapiro, B. 1981. Effect of cooling versus
seal - packaging with high density polyethylene on keeping qualities of
various citrus cuitlvars. J. Amer. Soc. Hort. Sci. 106 (5) : 536-540.

Ben-Yehoshua, S. 1985. Individual seal-packaging of fruit and vegetables in
plastic film - A new postharvest technique. Hort. Science 20 (1) : 32-37.

Bourne, M.c., Meyer, J.c., and Hand, 0.8. 1966. Measurement of food texture
by a universal testing machine. Food Technol. 20 :522.

Bourne, MC. 1968.. Texture profile of ripening pears. J. Food Sci. 33 : 2234.
Bourne, MC. 1978. Texture profile analysis. Food Technol. 32 : 62.

Brandt, M.A., Skinner, 5., and Coleman, J. 1963. Texture profile method. J.
Food SCI. 28 : 404.

Breene, WM. 1975. Application of texture profile analysis to lnstmmental food
texture evaluation. J. Texture Studies 6 : 53- 82.

Brennan, J.G., Jowltt, 8., and Mughsi, O.A. 1970. Some experiences with the
general foods textrumeter. An lnstron report. J. Texture Studies 1 : 167-
1 84.

CleIie, G.V., and Szczesniak, A.S. 1973. Guideline to training a texture profile
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Colllson, 8., Johnson, K., Oklkloiu, 0.0., and West, A.1980. Subjective and
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Davis, 0.0., Mc Mahan, P.F., and Leung, H.K.1983. Rheological modeling of
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Deak, T., Heaton, E.k., Hung, Y.c., and Beuchat, LR. 1987. Extending the

shelf life of fresh sweet corn by shrink-wrapping, refrigeration, and
irradiation. J. Food Sci. 52 : 1625.

56

57

DeMan, J.M.1969. Determination of potato texture. Can. Inst. Food Technol. J.
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Editors of modern plastics encyclopedia. 1983. Modern plastics, property and
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Finney, E.E.1972. Elementary concepts of rheology relevant to food texture
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Friedman, H.H., Whitney, J.E., and Szczesniak, A.S. 1963. The textrumeter - A
new Instrument for objective texture measurement.J. Food Sci. 28 : 390.

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Hadzlyev, D.1982. Research on processing Alberata potatoes. Agriculture and
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Hanson, L.P.1975. Commercial processing of vegetables. Noyes Data
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Harper, J.M.1981a. Extrusion of Foods. Vol.I. CRC Press, Inc. Boca Raton,
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Harper, J.M.1981b. Extrusion of Foods. Vol.Ii. CRC Press, Inc. Boca Raton,
Florida. .

Henig, Y.S., and Gilbert, 6.6.1975. Computer analysis of the variables affecting

respiration and quality of produce packaged In polymeric films. J. Food
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Henry, W. F., Katz, M. H., Pilgrim, F.J., and May, A.T. 1971. Texture of semi-solid
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Hickson, D.W., DIII, C.W., Morgan, R.G., Sweat, V.E., Suiter, D.A., and
Carpenter, Z.L.1982. Rheological properties of two heat-induced protein
gels. J. Food Sci. 47:783.

Huff, J.E.1972. Starch swelling pressure of cooked potatoes. J. Agr. Food
Chem. 20:1283.

Hughes, J.C., Fauiks, R.M., and Grant, A.1975. Texture of cooked potatoes:
Relatloship between the compressive strength of cooked potato disks and
release of pectic substances. J. Sci. Food Agric. 26: 731.

Institute of Food Technology Expert Panel a CPI - A report. 1974. Shelf life of
foods. Food Technol. 22 : 46.

iritani, W.M., Powers, M.J., Hudson, L., and Weller, L.1977. Factors Influencing
time to breakdown ( TTB ) of cooked potatoes tissue. Amer. Potato J. 54:
23.

Jadhav, S.J., Berry, L.M., and Clegg, L. F. L. 1976. Extruded French fries from
dehydrated potato granules processed by a freeze-thaw technique. J.
Food Sci. 41:652.

58

Kerr, R.W.1950. Chemistry and industry of starch. 2 nd edition, Academic Press
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Kim, K., and Hamdy, M.K.1987. Depolymerizatlon of starch by high pressure
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Kozempei, M.F., Craig, Jr., J.C., Sullivan, J.F., and Stabile, R.L.1986. Potato
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' Kuhn, G., Desrosler, N.W., and Ammerman, G.1959. Relation of chemical
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Larmond, E.1970. Methods for sensory evaluation of food. Publication 1284,
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Larmond, E.1977. Laboratory methods for sensory evaluation of food.Canadian
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Lee, Ch.H., lmoto, E.M., and Rha, Ch.1978. Evaluation of cheese texture. J.
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Le Tourneau, D., Zaehrlnger, M.V., and Potter, A.L.1962. Texturai quality of
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Leung, H.K., Barron, F.H., and Davis, D.C.1983. Texturai and rheological
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Linehan, D.J., and Hughes, J.C.1969. Texture of cooked potato. 1. J. Sci. Food
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Lujan, L., and Smith, 0. 1964. Potato quality XXV. Specific gravity and after
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Lyman, S., and Mackey, A. 1961. Effect of specific gravity, storage and
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Michigan potato research report.1987. Michigan State University Agricultural
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Mohsenin, N.N. 1986. Physical properties of plant and animal materials.
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59

Nonaka, M.1980. The textural quality of cooked potatoes .I. The relationship of
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Orr, P.H., Toma, R.B., Munson, S.T., and D'appolonia, B.D.1982.Sensory
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Potter, A.L., Neel, E.M., Reeve, R.M., and Hendei, C.E.1959. Change In the
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Pravisanl, C. I., Califano, A. N., and Caivelo, A.1985. Kinetics of starch
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Purvis, A.C. 1983. Effects of film thickness and storage temperature on water
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Radley, J.A.1968. Starch and Its derivatives. Chapman and Hall LTD.4 th
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Rasco, B.A., Downey, S.E., Dong, F.M., and Ostrander, J. 1987. Consumer
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Risse, L.A., Miller, w.R., and Mc Donald, R.E. 1984. Effects of film wrapping on
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60

Shane, F., and Shaman, P. 1973. Evaluation of some textural properties of
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Sherman, P. 1969. A texture profile of foodstuffs based upon well - defined
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Shiotsubo, T.1984. Gelatlnlzatlon temperature of potato starch at the
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Shiotsubo, T., and Takahashl, K.1984. Differential thermal analysis of potato
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Stollman, U., and Lundgren, 3.1987. Texturai changes In white bread : effect of
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Sych, J., Castalgne, F., and Lacroix, C. 1987. Effects of Initial moisture content
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Szczesnlak, A.S., Brandt, M.A., and Friedman, H.H. 1963. Development of
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Szczesnlak, A.S. 1963. Classification of textural characteristics. J. Food Sci. 28
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True, R.H., and Work, T.M.1981. Sensory quality of Ontario potatoes compared
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Van Beynum, G.M.A., and Roels, J.A.1985. Starch conversion technology.
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Warren, D.S., and Woodman, J.S.1974. The texture of cooked potatoes: A
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Zaehrlnger, M.V., and Le Tourneau, D.J. 1962. Texturai quality of potatoes.
' 1. Comparison of three organoleptlc methods. Food Technol. 16 :131.

Zaehrlnger, M.V., Cunningham, H.H., Le Tourneau, D.J., and Hofstrand,J.T.
1963. Standardization of a cooking method for objective evaluation of
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Zaehrlnger, M.V., Reeve, R.M., Talley, E.A., Dlnkel, D.H., and Hyde, R.B. 1967.
Spciflc gravity and composition of potatoes for various processing and
cooking purposes. Potato handbook Vol. XII .1967.

APPENDIX - A

61

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63

% MOISTURE CONTENT

uh

«33888833888

64

 

' H50 (.05) = 1.23

 

 

 

 

 

0W234557
STORAGE TIME ( MONTHS)

Fig.25. Change of the skin moisture content for the
simulated baked potato product during frozen
storage.

Columns which has the same letter are not
slgniflcamly different @ a s 0.05

~% MOISTURE CONTENT

65

 

100 I
- Em wows-0.17

I

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0 2 3 4 5 6 7
STORAGE TIME (MONTHS)

Fig.26. Change of the Internal moisture content for
the unpackaged slmulated baked potato
product during frozen storage.

Columns which has the same letter are not
significantly different @ a. a 0.05

 

% MOISTURE CONTENT

66

 

100
H80 (.05) = 0.57

 

 

STORAGE TIME (MONTHS)

Fig.27. Change of the Internal moisture content for
the simulated baked potato product In low
density polyethylene package during frozen
storage.

Columns which has the same letter are not
slgnlilcamiy different @ a = 0.05

 

 

  

 

 

 

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Hunter Color (L-Value)

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10 II III III
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6 7
STORAGE TIME (MONTHS)

Fig.29. Change of color L-value for the unpackaged

smulated baked potato product during frozen
storage.

Columns which has the same letter are not
slgniflcamly different @ a -.- 0.05

Hunter Color (L-Value)

69

 

 

1:: HSD(.05)=0.27
so
70
60
50
40
30
20
10
o ‘

 

O 2 3 4 I 5 6 7
STORAGE 11ME (MONTHS)

Fig.30. Change of color L-value for the simulated baked
potato product In low density polyethylene package
during frozen storage.

Columns which has the same letter are not
significantly different @ (x a 0.05

 

 

    

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. .////////.. .

  

 

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STORAGE TIME (MONTHS)

Fig.32. Change of color b-vaiue for the unpackaged
slmulated baked potato product during frozen

storage.

Columns which has the same letter are not

significantly different @ a = 0.05

Hunter Color (b-Value)

72

 

H80 (.05) = 0.18
' b

 

 

 

 

 

 

STORAGE TIME (MONTHS)

Fig.33. Change of color b-value for the simulated baked
potato product In low density polyethylene package
during frozen storage.

'oo’nufiitiicfiéfini £55. 1515?}... not
significantly different @ a = 0.05

 

    
 

 

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0 2 3 4 5

6 7

STORAGE TIME (MONTHS)

FIRMNESS (N)

10

74

 

 

 

H80 (.05) = 0.37

 

 
 
   
  
 
   

  

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0 2 4 5
STORAGE 11ME ( MONTHS)

Fig.35. Change of firmness for the unpackaged slmulated

baked potato product during frozen storage.

Columns which has the same letter are not
significantly different @ a a 0.05

FIRMNESS (N)

d
N
I

75

 

16

h

 

 

H80 (.05) = 0.37

-1

   

   
 

'1

   

 

 

0 2 4 5 6
STORAGE TIME ( MONTHS)

”9.36. Change of ""1100” for III. slmulated baked potato

product In low density polyethylene package during
frozen storage.

Columns which has the same letter are not
significantly different @ a a 0.05

 

 

 
 
 

  
 

  
 
 
 

.%

  

 

 

 

 

-
2222222
1 1.

7////////////.
.////////.
7//////////
.///////.
7/////..
7/////.

STORAGE TIME ( MONTHS )

COHESIVENESS

77

 

HSD (.05) = 0.38

 

 

 

0 2 4 I 6 7
STORAGE TIME ( MONTHS)

Fig. 38. Change of cohesiveness for the simulated baked
potato product during frozen storage.

Columns which has the same letter are not
significantly different @ a = 0.05

 

ADHESIVENESS (N.mm / min.)

2.0

 
 
 
 
 
  
   
   

78

 

  
 
 
 

 

 

H80 (.05) = 0.13

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STORAGE TIME ( MONTHS)

Fig.39. Change of the adhesiveness for the unpackaged

slmulated baked potato product during frozen
storage.

Columns which has the same letter are not
significantly different @ a = 0.05

ADHESIVENESS (N.mm I mm.)

79

 

H50 (.05) = 0.13
a

 

 

 

 

0 ' 2 I 4 1 5 l 6 A 7
STORAGE 11ME ( MONTHS)

Fig.40. Change of the adhesiveness for the simulated
baked potato product In low density polyethylene
package during frozen storage.

Columns which has the same letter are not
significantly different @ a = 0.05

 

 

 

_/////////

 

  

2// 4/ 5 6/
STORAGE TIME ( MONTHS

 

GUMMINESS (N)

81

 

     
   
    
  
      

 

 

H50 (.05) = 0.09

  

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STORAGE 11ME ( MONTHS)

Fig.42. Change of the gummlness for the unpackaged

slmulated baked potato product during frozen
storage.

Columns which has the same letter are not
slgnlflcamly different @ a = 0.05

82

 

2 HSD (.05) = 0.09

 

GUMMINESS (N)

 

 

 

STORAGE TIME ( MONTHS)

Fig.43. Change of the gummlness for the simulated baked
potato product In low density polyethylene package
during frozen storage.

Columns which has the same letter are not
significantly different @ a = 0.05

 

 

 
 
   

  
 

 

  

 

 

54.20.354.20
0000000000

.I///////.
_////////..
_/////////,..

STORAGE TIME ( MONTHS)

APPENDIX - C

84

85

.25. so»... 9 28:29..” :

 

3.5 84.2 2 Ohm

nmd 36 3.1m o— coda—23.:

85 ....Es 3.3 3.62 n 822m
ocd ......wméa and: 3.8m: N dams—5.32%
OP..— 2...; 326m 3.89am Eoeooom oodsom

m :32 no Sam ..O 33on

 

620:2. 33:22 oofiEEo. Lo
6:23.022. 3.2.2. 32 5 639.395 coco-o 6233222.
ooxoa 355E... c. .....e .o 2:8.oE 3. 85:2. 3 23.22 .m. 2%...

86

.26. S... no G ...oo........m ..

 

no... we... m . 8.2m

wood .35..” .nd .1 .nm o. 3.330....

.5... to... 3... 2.3 n 82%

cod 3%.: mafim 5.2. a 4%.va .30....

do... 2...; 3.23m 3.83m 83.qu 3.3m
m :32 h.O Sam ..O 3035

 

.oo..o3 0.3.3.0.

385E... .o 63.3.3.3 5.2.3 .3. ... 639.03.... 3.2.. .333
0.23 3.3.. 3.2.3... ... .o..o.... 3 2.3.2.. .o. 33...... .o 22.52 .0. 33h

87

..25. S... u. @ 28:20.. ..

 

:6
86 ......de no...
ooéivcd—N No.3“
2.6:...”th nwdm

 

do... 2...; 0.01%
m 5.02

me.m w . 8.5
3.2. o. 3.30.0...—
862 n 0.22m
3.2 N 88... .32...
magnum 52.00.... 00.:om

..0 Sam ..0 monumen—

 

.00..2.2_ 0.02.0.0. 00.0282

.0 6:22.022. 5.2.0.. 30. ... 60002002.: 00.0.0 .030...
0.0.2. 03.0.. 00.2220 ... 03.0.. .. .200 .0. 02.2.2. .0 0.3.0.2 .... 030...

88

..25. S... «a Q 28556 ..
..25. 3... an .9 28:25 .

 

 

8... m: 3 Sum

Sod .25 85 :4 S 82222.:

83. :38 an; :6 m 3:85

:55 :35 $3 3; a $0me gee

...on 2:3, 32:5 3.335 Eocooum 023m
m :32 ac Sam .8 mop—won

 

628:2. snares.
33552 3 65:53.2. 2.2.3 30. 5 638.03.... :28. 3:02..
282. 09.3 3.23:... ... 33> .- 3.8 .3 85:2, 3 «3222 d. can»

89

..26. 3... «a .9 385.35 ..

 

 

had 2:. m _ Hohm—
ood 1.3.2 N.N.m 2.3 w cote—:25
cod .....ovdh RAN 3.3 v a«35
85 252% 3.2; :33 a 335.329
33> 2.23m 333% 82.35 330m

do: m :32 mo Sam no mop—won

 

$2.32. «32.22 522:5!
3 65:53.2. 2.2.2. to. 5 638.395 022.. .259:—
282. 3x3 333...... ... 335...“. .2 85:2. .0 23:23 6. 03¢...

..22 5... an 9 28:32.... ..

 

 

90

86 3.... m. 32m
cod 1.2.6— 3.0 Sum w n35.225.
8... :52 ...... 3.. .. omeoa
ca... 1.2.... $6 «a. a A.mOM$..aofi.
do... 2...; 033m 3.315 80.3on 35cm

m 532 .3 Saw mo 32on

 

.oogoaon 033.29.
3.2.25. 3 6.3.3.022. 3.2.0.. :6. ... 633.03.... .838 8:02..
882. 98.2. 3.9.5... ... 3.52.9.3 .2 85...; .o 22:82 .3. .33

91

.26. no... u. 9 28:29... .
.1: an 02.9.5... 03 822. 82.... +

 

 

mm... tan. 2 ......m

:6 o. .o :6 m 5.898...—

S... a: a... 3.2 v omega

and 8.. cm... «5.. N A.mwv~mv..a2.u

do...— o=.a> 2.25m 3.33m 82.3.."— 3.3m

m + :32 + ..o Sam .8 monumen—

 

.oo..o:2. 032.22
322.33. .0 6.3.3822. 3.2.2. :6. ... 638.03.... no.8. 8:3...
282. 09.2. 33.3.... ... 32.2.3200 .2 02.5.2. .0 0.0222 ...p. 03....

92

.26. 3... an .9 ...8........m ..
.26. 3... a.. .9 28:30.0 .

 

 

Nod wad n . 8...".—
ood «and cad 3.... w 5.80.0...—
8... 3.3.: 3.... 8.. .. .585
cc... ......nvdw. 2.6 «.6 a A.m0va..ao.F
do..— 020> Saga megam 82.00.."— 330m

m 5.02

..o .....m .0 30309

 

.00guaon

0.02.20. 020......0. .0 65.2.0300 5.2.0.. ...0. ... 6000.309... 00.20
8:00... 880.. 08.0.. 020.250 ... 002.....an .0. 030...... .0 0.0205 .0... 0.00...

APPENDIX - D

93

94

Table -13. Changes In the moisture of the skin for simulated
baked potato product In different packaging
materials within time of storage.

 

 

 

Treatment Mean#
WIO 37.233
LDPE 51.103
R.P 52.71a
SEM 2.14

 

WIO :- without packaglng

LDPE a packaged in low density polyethylene.
E.P a packaged in laminated retotable pouch.

0 Mean is calculated from 6 values.

Means within columns having different letters are
significantly different (p=0.05).

95

.306"... ...0.0...0 2.002.320 0.0 0.0..0. 0.0.00.0 9.0.0.. 00.00.00 5...... 0000:

0.2.0.. .6. ... 0000.000 u 0.0..

.000.>...0>.00

.0020) o 50.. 0323200 0. :00: t
...0000 0.00.0.0.

0205...... ... 0009.2... u 0...

0509.02. 50...... u 0....

 

 

hm... hm... um... um... um... um... 2mm
0 5.05 0 3.05 0 3.2. 0 002. 0 2.2. 0 00.2. ....—
0 N02. 0 m2: 0 3.02. 0 00.02. 0 3.0.. 0 3.2. was
0 8.2. 0 3.2. 0 3.02. 0 2.0.2. 0 3.2. 0 Snow 0;?
00002 00002 #0002 00002 00002 #0002 $008.00....

5.8... .... 5.5... .... 5.52 ...m 5.5... .... 5.52 .... 5.52 a... 2.... 00220

 

600.80 .0 0.0.. 5...... 0.0.3.0... 9.39.000
20.0...0 ... .0000... 0.0.0.. 00x00 00.0.0030 .0. 0.3.0.0... .23.... 0.... ... 00000.5 .3. 0.0:

96

400.0»... 0.0.0.00 2.000.000; 0.0 0.0..0. .00.0...0 000.00 00.00.00 0.0..... 0000:

0.0000 30. ... 0000.000 a 0......

.000......0...00

63.0.. 0 EC.— 0033200 0. :00: n
.0280 0.00.0.0.

00.00.50. ... 0009.000 u 0...

00.08.02. .00....3 u 0....

 

 

 

2.0.0 2.0.0 2.0.0 5.0 2.0.0 2.0.0 2mm
0 3.00 0 3.00 0 00.00 0 3.00 0 00.00 0 3.00 ......
0 0000 0 .0060 0 00.2.0 0 00.00 0 00.0.. 0 0.0.2. was
0 0000 0 3.00 0 0060 0 00.00 0 00.00 00 3.0.. 0.3
00002 00002 00002 00002 00002 00002 0.008.000...

5.52 .... 5.52 ...0 5.52 ...n .080. 5.. .082 .0. 582 0:0 2:0 00230

 

600.20 .0 0.0.. 0.0..... 0.2.0.0.0 00.003000
.00.0...0 0. 8000.0 0.0.00 08.00 00.0.0000 .0. 00.0.. .. .0.00 0... ... 0000000 .07 0.00...

97

43...»... 2.0.2.... 2.52:5... 2. 22.2 39.8.... 9.32. 2.523 55.3 2.3:
63.9. 0 ES. 022328 a. can: t

.532. 03820.
6:03:82: 0855...... ... 338.02. u ...:

 

 

£38 to. ... 38.8.. a man... 2.3.8.. 52...: a 0.3

2... 26 2.: 2d 25 26 2%
a 2.... a 3.2 a 8.2 a 3.2 a .32 a 8.2 .3.
.... 2.2 a 3.2 a 8.2 a 3.2 a 3.2 a 3.2 was
a 2.: a 3.2 a 3.: a 2.: a 3.2 a 3.2 . 0;?

 

#:aoz *an: #:602 #:502 *Euoz #:aoz maEDEuMOHP
5.52 5.. 5.82 5.. 5.52 ...... 5.82 .3. 58: en 58: EN 25. 0.22m

.322» .o 2.... 55.3 22.82.. 2.3882.
822.... ... 8:3... 282. 09.3 35:53 .2 3.... a .23 2.. 5 39.2.0 .3. 03a...

400.0»... ...0.0...0 2.002.320 0.0 0.2.0. ...0.0...0 00.00.. 00.00.00 5...... 2.00:
.0022. 0 .00.. 00.0.0200 0. :00: 0

£000.. 0.00.0.0.
0205...... ... 00.8.02. u 0...

00035020..
0502.02. 52...; u 0....

0.2.00 30. ... 000200.. a 0.0..

 

 

98

 

m... m... m... m... m... an
a 9... a .n . a and a mu. 0 c... ......
0 h... 0.....m 0 3.. 0 0.... 0 mm. min...
a and 0 cm. 0 3.. 0 m0. 0 o... 0;»
...—.002 0:00... 0:002 0:002 0:002 3:08.00...
0:... ...h 0:... ...0 08.. ...n 0:... ...0 0:... 0:~ 0:... 09.35

 

600.20 .0 0:... ...—....s 0.2.0.0... 0508.000 30.050 ...
.0000... 0.0.0.. 00...... 00.03:... .0. 00000202.: 0... ... 00002.0 ...? 0.00...

99

..00.0u0. .00.0...0 2.0020020 0.0 0.3.0. .00.0...0 000.00 0050.00 0.0..... 0000:
.0022. 0 0.0.. 00.0.0200 0. 000: 0
.00000 0.00.0.0.

 

 

000.00.00.00 00.00.50. 0. 0009.000 u 0....

0.0000 30. 0. 0000.000 a 000.. 0509.000 .02....» a 0....
mm... 00.0 00.0 00.... 00.0 2.00
0 0.0 0 0.... 0 00.0 0 00.0 0 00.0 0...
0 P... 0 00... 0 00.0 0 .0.0 0 00.0 M00...
0 0...: 0 00.0. 0 3.0. 0 00.0. 0 00.0. 0:5

 

0:002 #0002 0:002 0:002 0:002 0.005.000...
5.52 .0.. 5.5... .00 .082 .00 0.82 0.. .088 .50 2.... 00220

.000.0.0 .0 0.0.. 0.0..... 0.2.0.00. 00.000000
.00.0...0 0. 8000.0 0.0.00 08.00 00.0.00..0 .0. 000000.“. 00. 0. 0000000 .0.. 0.000

100

200.000. .00.0...0 2.0020020 0.0 0.0..0. .00.0...0 000.00 00.00.00 0.0..... 0000:
000.2. 0 .00.. 00.0.0200 0. 000: 0
.00000 0.00.0.0.

 

 

000.00.00.00 00.00.50. 0. 00002000 a 0...

2.0000 30. 0. 0009.000 u 000. 00.000000 52...: u 0.2.
00.0 00.0 00.0 00.0 00.0 2%
0 0... 0 00.. 0 00.. 0 0... 0 00.0 0...
0 00.. 0 .00.. 0 0... 0 0... 0 00.0 as
0 00.0 0 00.0 0 00.. 0 00.. 0 00.. 0.3

 

0:002 0:002 0:002 0:002 0:002 0.008.000...
.052 .... 0.5: .00 0.82.... .08... .0.. .080. .00 2.... 00.020

600.80 .0 0.0.. 0.0..... 0.2.0.00. 00.000000 .00.0...0
0. .8020 0.0.0.. 00...... 00.0.00... .0. 0000.20.00 0... 0. 00002.0 .0.. 0.0....

"‘WEVIEWLTMEWJNAWMUMWE'VS