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EFFECT OF NITRITE ON THE FLAVOR
0F CURED PORK

Thesis for the Degree of M. S.
MICHIGAN STATE UNIVERSITY
IUE CHUNG CHO
1968

 

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ABSTRACT
EFFECT OF NITRITE ON THE FLAVOR OF CURED PORK
by Iue Chung Cho
The aim of the present study was concerned.mainly with the effect
of nitrite on the cured flavor of pork. It was not concerned with the

constituents produced by the action of nitrite on pork.

 

The paired, left and right, Longissimus dorsi muscles of pork were
used. Both samples were cured in a pickle, in which sodium nitrite was
the only variable. Panelists were blindfolded and taste tests were con-
ducted. Taste panels were of consumer type. The statistical treatment
of the data obtained from the triangle taste tests was made using the
table taken from.the Guide Book for Sensory Testing by Ellis (1961).

The statistical results showed that panelists were able to identify the
different sample at a statistically significant level in the triangle
taste tests. In the paired taste tests, a statistically significant
number of panelists chose the sample containing sodium nitrite as having
more cured flavor. Since sodium nitrite was the only variable in the
curing pickle, these results indicate that sodium nitrite causes some
change in the flavor of cured pork.

To determine the effect of nitrite on the flavor of cured pork
without the influence of salt and sugar, the samples were cured in dis-
tilled deionized water, in which sodium nitrite was the sole curing agent.
The results of the taste panel tests indicated that sodium nitrite alone

produced a certain flavor. This action occurs during either curing or

Iue Chung Cho
cooking.

The effect of smoking on the flavor produced by sodium nitrite
was also studied. Samples were cooked, sliced and smoked in that order.
It appeared that smoking did not affect the ability of panelists to
identify the different sample in the triangle taste test. Furthermore,
panelists chose the samples containing sodium nitrite as having more
cured flavor over those containing no sodium nitrite, even though both

samples were smoked.

EFFECT OF NITRITE ON THE FLAVOR OF CURED PORK

BY
Iue Chung Cho

.A THESIS

Submitted to
.Michigan State university
in partial fulfillment of the requirements
fOr the degree of

MASTER OF SCIENCE

Department of Food Science

1968

.ACKNOWLEDGEMENTS

The author wishes to express his appreciation to Professor L.J.
Bratzler for his thoughtful guidance and encouragement throughout this
study and for his aid in the preparation of this manuscript. Acknow-
ledgement is given to Dr. C. L. Bedford, Professor of Food Science.

He also wishes to thank all the graduate students and staff of
the Meat Laboratory for their encouragement and cooperation.

The author is especially grateful to his wife, Barbara, for her
sacrifices and for making it all worthwhile. Last, but not least, the
author desires to acknowledge his parents fOr their stimulation and

encouragement to pursue a higher degree of education.

ii

INTRODUCTION . . . .

TABLE OF CONTENTS

LITERATURE REVIEW . . .

Meat Flavor

EXPERIMENTAL PROCEDURES . . .

Samples

Curing Methods . . . . . . . . . . . . . . . . . .
Role of Curing Ingredients . . . . . . . . .
salt 0 O O O I O 0 O O O O O O O O O 0 O O O O 0
Sugar . . . . . . . . . . . . . . . . .
Nitrite and Nitrate . . . . . . . .......
Taste Panel Methodology . ............. . .
Curing and Curing Yields . ..............
Cooking . . . . . . . . . . . ..... .
Smoking . . . . . . . . . . . . . . .
Panel Presentation . . . . . . . . . . .
Statistical Analysis . . . . . . . . . . . . .
Chemical Analysis . . . . . . . . . . . .
Samples . . . . . . . . . . . . . . . . .
Maisture............ ..
Ether Extract . . . . . . . . . . . .
Sugar . . . . . . . . . . . . ....... .
Salt .'. . . . . . . . . . . ..... . . .
Nitrite . . . . . . . . . . . ..... . .
Protein . . . . . . . . . . . . .
PhenO]. ., a go o o o o o o o o 0

EXPERIMENTAL RESULTS AND DISCUSSION .

Effect of Nitrite on Cured Flavor of Pork

Effect of Smoking on the Cured Flavor of Pork Due

to Nitrite . .

iii

0 O

O O O O I O 0 O

Page

Cho-54>“

12
13

15

15
15
16
16
16
17
17

17
17
17
17
18
18
19
19

22

22

Weight Change During Curing ............ . . . . 27

Chemical Analyses ................. . . . . 28
SUMMARY AND CONCLUSION . . . . . . . . ..... . . . . . . . . . 31
BIBLIOGRAPHY ................... . . . . . . . . 32
APPENDICES . . . . . . . . . ........... . . . . . . . . 37

Appendix I . . . . . . ............. . . . . . . 37

Appendix II ................. . ..... . 38

Appendix III ......... 7 ............... 39

Appendix IV ...................... '. . 40

iv

Table

 

 

10

LIST OF TABLES

Composition of the pickle used in the trials

1 through 5. . . . . . . . . ..... . . . . . . . . . .

Results of statistical analyses of the data obtained

from the triangle taste tests (1 through 5) . . . . . . .

Results of statistical analyses of the data obtained

from.the triangle and paired taste tests (6, 7, 5 8) . . .

Composition of the pickle used in the trials 9, 10, G 11 .

Results of statistical analyses of the data obtained

from the paired taste tests (9, 10, a 11) ........

Results of statistical analyses of the data obtained

from the triangle and paired taste tests (12, 13, a 14). .

Results of statistical analyses of the data obtained

from.the triangle and paired taste tests (15, 16, G 17). .

Results of statistical analyses of the data obtained
from the paired taste tests (meat containing 2% sodium

chloride) . . . . . . . . . . . . . . . . ._. . . . . . . .

Results of statistical analyses of the data obtained
from the paired taste tests (meat containing 1% sodium

chloride) ..... , ........ . ............

Results of statistical analyses of the data obtained

from the paired taste tests (smoked samples) . . .....

. 23

. 24
. 24

25

25

. 27

28

. 29

. 30

Figure

LIST OF FIGURES

Chemical Reaction of Myoglobin. .-. . . . . .
Hypothetical Reaction of Myoglobin . . . . .
Example of Questionnaire Used in Triangle Test

Order of Sample Presentation

vi

Page

10
16

17

INTRODUCTION

The curing of meats has no definite beginning date. Salt curing
and smoking of meats fer preservation was practiced in the time of Homer
(about 900 B.C.) (Jensen, 1945). He stated that the salting of meats
was begun in the saline deserts of Hither Asia and along the sea coasts.'
In the old times, curing or smoking of meats was used merely as a method
of preservation. Salt is the oldest known preservative and has been used
in many countries as a meat preservative. Saltpeter also has been used
for a long time to preserve meat from spoilage and discoloration (Hoagland,
1908). Today the public has awakened to an appreciation of flavor as one
of the greatest attributes of an acceptable food product. As a result,
more attention to flavor in food products has been paid by the manufac-
turers. The trend of curing has moved from preservation toward producing
flavor to satisfy the consumer's taste.

Although nitrate has been used for a long time, little attention
had been paid to the scientific aspects of the bright red color fOrmation
which occurs during the process of curing until 1890-1910. It was finally
discovered then that it was the nitrite, resulting from bacterial reduction
of nitrate, that was actually responsible for the formation of the
thermally-stable cured meat pigment (American Meat Institute Foundation,
1960). It is now accepted that the development of the bright red color
in cured meat is due to the interaction of nitrite with the myoglobin of
the meat which yields a pigment, nitroso-myoglobin. Also, nitrite is

known to act as a bacteriostatic. agent. However, little is known about

1

2
its contribution to the flavor of cured pork (cured flavor). English
researchers (Brooks gt al,,_1940) have reported that the characteristic
cured flavor is due primarily to the action of nitrite on the meat. They
claimed that a satisfactory bacon can be made by using only sodium chlor-
ide and sodium nitrite.

The investigation reported here was undertaken to verify their work
and to obtain more detailed information on the effect of nitrite on cured
flavor of meat. The objectives of the study were:

1. To determine what effect nitrite has on the flavor of cured pork°

2. To determine what effect wood smoke has on the flavor of cured

pork cured with nitrite.

LITERATURE REVIEW

Curing.Methods

 

Curing consists of the absorption of sufficient salt to preserve
the meat, the fixation of color and the development of that distinctive
flavor and texture which distinguish cured from fresh meat (Kerr 25 al.,
1926). The ingredients commonly used in curing mixtures are sodium
chloride, sugar, sodium and potassium nitrate, and sodium and potassium
nitrite.. Sometimes vinegar is used (Frazier, 1967). 1

Brandly'§t_gls (1966) described three methods of curing meat.

These include the sweet pickle cure, plain pickle cure, and dry cure.

The sweet pickle cure consists of a 100° salometer strength solution of
sodium.chloride which is then diluted to the desired strength of pickle
'with water. To the diluted pickle solution the sugar and nitrate and/or
nitrite are added. The meat cut may be submerged or covered in the pickle
solution; or, the pickle may be injected or pumped into the body or through
the arterial system of the meat cut. The internal temperature of the meat
to be cured should not exceed 38°F. When using the plain pickle cure, no
sugar is added to the pickle. Occasionally, however, nitrate or nitrite
are added to the pickle as a variation of the plain pickle cure. The dry-
curing method consists of rubbing all sides of the meat with the dry-cure
mixture (salt, sugar, nitrate and/or nitrite).

Ziegler (1964) stated that there is not much difference in the
shrinkage between dry and sweet pickle cured pork after 60 days of aging.

3

There will be a gain of an average of 5% in sweet pickle cured hams,
whereas a loss of 5% to 7% occurs in dry cured hams. However, according
to Skelly 23 a1. (1960), shrinkage losses in dry cure during aging may be
30%. Furthermore, the quality of aged hams is not uniform. In the study
of characteristics of hams during aging by Kemp g£_§l, (1957) it was
shown that shrinkage in dry cure increased at a decreasing rate each
month and.ranged from an average of 8.6% after smoking to 30.5% after 6

months aging.

Role of Curing_1ngredients

 

Salt: Salt is the most important curing ingredient. Sufficient

 

concentrations of salt inhibit microbial growth. Salt also contributes
to the flavor of food (American Meat Institute Foundation, 1960).

Jensen (1945) reported that although salt was the most active
preservative used in meat=curing solutions, it did not inhibit all bac-
teria. Its function is a selective action. Aerobes, facultative anaerobes,
and micrococci were more resistant to salt than anaerobes. The rods were
more easily suppressed by salt than cocci.

Bullman and.Ayres (1952) showed that no spoilage was observed
at concentrations exceeding 4.4% sodium chloride while varying degrees
of bacteriostatasis were shown by levels of 3.5% to 4.4% salt in pork
trimmings. However, there are many conflicting reports regarding the
effective preservation concentrations of curing salt against putrefactive
anaerobes. Tanner and Evans (1933; 1934) explained some of these causes.
Species and strains varied in susceptibility to the same salt concentration
and similar organisms tolerate various levels of the same salt concentra-

tion in different substrates.

Investigations by Rockwell and Ebertz (1924) showed that dehydra-
tion by salt is not the only preserving factor. They concluded that
there are four other factors involved in the preserving action of sodium
chloride: 1) direct effect of chloride ion, 2) removal of oxygen from
medium, 3) sensitization of the test organism.to C02’ and 4) interference
with rapid action of proteolytic enzymes.

The biochemical mechanisms during curing were extensively studied
by Callow (1947). Due to osmotic pressure, certain proteins diffuse into
the salt solution. The flow of water is then reversed after the fermation
of a protein salt complex. After the diffusion of salt into muscular
tissue, the micro-structure is altered. The texture becomes much more
jelly-like, and the muscle juice is held.more firmly. Grant and Gibbons
(1948) also studied the biochemical aspects of curing° They stated that
the chloride ions which were bound by the tissue were released by the
bacterial action and the enzymatic breakdown of the muscle tissue. The
chloride ion then re-united with the sodium ion in the outer tissue fluids
to ferm.sodium chloride. This action gives meat a salty taste. 1

The relationship between length of curing and the thickness of
ham.was studied by Miller and Ziegler (1939). They feund that higher
sodium chloride content was obtained by longer curing periods per unit of
ham. 'Wistreich g; 31. (1959; 1960) showed that accumulation of sodium
chloride increased with an increase in temperature and brine concentration,
and that the accumulation of sodium chloride was related linearly to 2
concentration, but logarithmically to time.

Investigations by Pearson gt a1. (1962) and Goembel (1962) showed
that the optimal level of salt in cured ham.was 2.5% combined with 1.1%
sugar. .Also, Marquardt.§£_§l, (1963) found that there were no significant

differences in consumer preferences between 1.5% and 3.0% salt, whereas

there was a significant difference between 1% and 3% sugar.

Sugag: Sugar is used.mainly to counteract the harshness of the
salt cure and to improve the flavor and texture of the meat (Levie, 1967).
It also provides energy for the growth of bacteria (Mbulton and Lewis,
1940). According to Ashbrook (1955), sugar is broken down into organic
acids by microorganisms. Lactic acid is one of these acids and gives
a pleasant flavor to meat.

Urbain 32 El. (1940) studied the correlation between color changes
of meat and the growth of microorganisms utilizing sugar. They observed
that dextrose, mannose, and sucrose produced significant color changes in
the blood pigments, oxymyglobin and nitric oxide myglobin. They stated
that color change requires the reducing conditions which are provided by

microbial growth.

 

Nitrite and Nitrate: The scientific study of color fixation of
cured meat was started in Europe in 1890-1892 by Polenske, according to
Lewis gt_gl, (1925). 'They reported that Polenske feund nitrite in cured
meat and curing solutions, and that the nitrite was fermed by bacterial
reduction of nitrate. Lewis gt_§1, (1925) fUrther stated that Lehman and
Kisskalt studied the function of nitrite. Lehman showed the color change
by boiling fresh meat with nitrite in the presence of a little acid.
Kisskalt proved that nitrate could fix the color if the meat was left in
contact with the nitrate several days.

Hoagland (1908), in his study of the action of saltpeter (potassium
nitrate) upon the color of meat, referred to the work by Weller and Riegel.
These workers obtained a bright-red ether extract from sausage and other
cured meat and found that the extract had an absorption spectrum similar
to methemoglobin. This extract was also obtained from meat containing

blood and treated with nitrate. Haldane (1901) extended Weller's and

Riegel's work. He identified the coloring matter of uncooked cured
meat as nitroso-hemoglobin by its absorption spectrum. He showed that
nitroso-hemoglobin and some methemoglobin were produced by the reaction
of nitrites on blood. He concluded that the nitroso-hemoglobin was fermed
by the action of nitrite on hemoglobin in the absence of oxygen and in
the presence of reducing agents. He further showed that the red color
of cooked cured meat was due to the nitroso-hemochromogen produced by
decomposition of nitroso-hemoglobin when heated. Ostertag (1904) stated
that the red color of salt meat is not due to the saltpeter, but to
nitrites, and perhaps nitric oxide Which is formed from the saltpeter
in the brine.

No attention was given to the changes which take place during
the curing process in this country until Hoagland (1908) started his
experiments on this subject. He verified and extended.Haldane's (1901)
work. Hoagland concluded that the nitric oxide.which.was formed by the
reduction of the nitrites within the meat was an intermediate step between
nitrates and the formation of nitroso-hemoglobin.

I .After the formal authorization of the first experiment involving
direct use of nitrite, Kerr 2E.§l: (1926) undertook their experiments to
prove that sodium or potassium.nitrite can be substituted for sodium or
potassium nitrate in the curing of meat. They reported that the nitrate
must be reduced to nitrite before it becomes active in meat curing. They
fOund that there was no difference in flavor between the nitrite cured
meat and that cured with nitrate. In addition, meat cured with nitrite
was not inferior in quality or wholesomeness to meat cured with nitrates.
They observed a smaller amount of the residual nitrite in the nitrite
cured meats than in the nitrate cured.meat. .As a result of their work,

the use of sodium nitrite in meat curing was authorized by the Department

of Agriculture, through Amendment 4 to Bureau of Animal Industry Order
211 (revised) (USDA, 1926). The entire amendment is subject to meat-
inspection regulation. The Bureau of Animal Industry issued Circular
No. 1370 permitting the addition of 1/4 ounce of sodium nitrite per hundred
pounds of meat. The Bureau fUrther ruled that the finished product should
contain no more than 200 parts per million of sodium nitrite (ANHF, 1960).
Anson and Mirsky (1925) investigated the reaction between nitric
oxide and hemoglobin. They stated that hemoglobin in the presence of
nitric oxide is oxidized to methemoglobin, which then fOrms nitric-
oxide methemoglobin. Keilin and Hartree (1937) cite work by Haurowitz
in which he claimed that methemoglobin was reduced by nitric oxide to
hemoglobin which then combined with more nitric oxide to form.nitric
oxide hemoglobin. Keilin and Hartree (1937), however, contended that
these interpretations were only partly correct. Their conclusion was that
nitric oxide combines with both hemoglobin and methemoglobin. Nitric
oxide ferms a very stable compound with hemoglobin, whereas with methemo-
globin it forms an easily reversible compound which is not stable and
undergoes reduction to nitroso—hemoglobin on standing.
The chemical nature and reactivity of meat pigments were studied
at the American Meat Institute Foundation by Schweigert (1956). His
study concentrated on myglobin which is referred to as muscle hemoglobin.
He presented the schematic diagram showing the several chemical reactions

involved in color changes of fresh or cured meats. (Fig. l).

 

02(oxygenation)
Myoglobin A. Oxymyoglobin
(purplish red) ..; (bright red)

 

 

   
    
   

Q’CQ ‘
0!:

Nitrous acid
(reducing:
1’ agents)

 

Metmyoglobin

Nitric oxide myoglobin oxidat ion 3
(pinkish red) (-NO) (brown)
heat oxidation
(irradiation)
Nitric oxide de- oxidation 3, ' Green Compounds
natured.myoglobin (Oz, H202, light)
(pinkish red)
oxidation

Colorless Compounds

Figure 1. Chemical Reaction of Myoglobin
(from Schweigert, 1956) .

Recently, extensive studies concerning the color development and
color stability in meat processing have been performed. According to Fox
and Thomson (1963), the myoglobin first had to be oxidized to metmyoglobin
befbre it could combine with.nitric acid. This report was supported by
Taylor and Walter (1967). Their experiment showed that nitrite rapidly
oxidized oxymyoglobin to metmyoglobin. They also suggested that reduction
of nitric oxide metmyoglobin by mitochondria may be a possible mechanism
for the formation of nitric oxide myoglobin during curing. However, a
later report by Fox 23 31. (1967) indicated that nitroso—myoglobin may be
formed byreducing agents such as ascorbate without being converted to
nitroso-metmyoglobin. Solberg(1967) made an attempt to interpret a dual

pathway in the fermation of nitroso-myoglobin. ‘Without added reductants

10

the pathway suggested in Figure 2 may be followed. But in the presence
of reductants, both the pathway in Figure 2 and an alternate pathway in
which reductants provide the electrons may be fellowed:
Fe++cyt c
(ferrocytochrome c)

NO2 cytochrome oxidase (mitochondria)
(anaerobic),

NO - Fe*“cyt c
(nitrocylferricytochrome c)

 

[—metmyoglobin
/—-mitochondr ia

thlD,--fi--\
(reduced nicotinamide
adeninedinucleotide) T
\

FE**cytochrome c + NOmet NET' +_NAD
‘(nitrosometmyoglobin)

 

mitochondria. , NADH2

NOMb + NAD
(nitrosmyoglobin)

Figure 2. Hypothetical Reaction of Myoglobin
(from Solberg, 1967)

According to Frazier (1967), sodium nitrate is mildly bacterio-
static in acid solution, especially against anaerobes. Sodium nitrite
also has some bacteriostatic effect in acid solution. Tarr (1941) feund
that low concentrations of nitrite can delay bacterial spoilage of fish
in acid.medium, but not above pH 7. Bullman and Ayres (1952) reported
that nitrite inhibited the germination of the spores of putrefactive
anaerobes (P.A. 3679) in inoculated emulsion. According to Castellani

and Niven (1955), nitrites do not have any practical preservative action

11

on those organisms not killed by sodium chloride in cured meats.
Ingram (1939) attempted to determine the mechanism of inhibitory
action of nitrite on bacteria. He found that nitrite very strongly in-

hibited the oxygen uptake of Bacillus cereus. Therefbre, nitrite

 

interferes with the cytochrome system. However, Tarr (1941) found that
there was no relationShip between inhibitory action of nitrite and its
effect on respiration. Furthermore, the results obtained by Castellani
and Niven (1955) did not support Ingramfs explanation. Their results
showed that nitrite was quite effective as a bacteriostatic agent in an
anaerobic medium autoclaved with glucose. Their explanation was that
undissociated nitrous acid is the active form in the inhibitory action.
Brooks EE.El: (1940) investigated the effect of nitrite on the
cured flavor of bacon. In their experiments blindfOlded tasters were
aSked to indicate their preferences. Three pieces of'pork from the

same pig, each weighing about 3,500 g., were cured in three different

pickles:
NaCl g./lOOg. water NaNO3 g./100g. water NaNO2 g./100 g. water
Pickle A 16 2.8 0.08
Pickle B 16 2.8
Pickle C 16

Their results showed that samples containing sodium nitrite were preferred,
but there was no clear-cut preference for one particular concentration.
In conclusion, they stated that the characteristic cured flavor of bacon
is due primarily to the action of nitrite on the meat.
Smoking
The primary fUnction of smoking originally was to enhance the pre-
servative action of curing, but today smoking is used.mainly to improve

the flavor (Lawrie, 1966). In addition, smoking also improves the color

12

of the products (Tilgner, 1957). Lea (1933) reported that smoking acts

as an antioxidant. His report was based on the peroxide value. The
peroxide value of_smoked bacon was lower than that of unsmoked bacon after
28 days of storage at -10°C.

According to Hess (1928), the smoking of fish fillets inhibited
the growth of microorganisms. .Also, White §£_§l, (1942) reported that
the smoking of bacon reduced the number of surface bacteria "by 10,000
times" of those of unsmoked bacon. In a study of lethal effect of smoke
on cheddar cheese, Hedrick ggnal. (1960) feund that hardwood sawdust
smoke had bactericidal' action on the surface bacteria of freshly cut
cheddar cheese. Jensen (1949) stated that smoking greatly increased the
keeping qualities of meat. This statement was supported by White 33 El-
(1944). They found that smoking of baCon extended the storage period to
2 months from 1 month at the same temperature..

Phenolic compounds play a major role in smoke flavor (Husani and
Cooper, 1957). Consequently, total phenolic content in smoked foods has
been used as the index of the degree of smoking (Hanley'g£“§1., 1966).
Shewan (1949) found more phenols at the surface than under or at the
center of fish fillet and sausage. Tucker (1942) also found phenolic
compounds concentrated at the surface. All of these results indicate that
most of the flavoring components of smoke are deposited at or near the

surface of the smoked products.

Meat Flavor

 

v

Lawrie (1966) defines flavor as a complex sensation comprising
odor, taste, texture, temperature and pH. Odor and taste are most diffi-
cult to define objectively. Four basic tastes, sweet, salty, bitter,

and sour, are generally recognized today (HOrnstein and Teranish, 1967).

 

13

Due to the greater range of olfactory responses, there are many types of
odor claSSifications. Amerine §t_al, (1965) gave a classification of
odors which included 7 types; spicy, flowers, fragrant, resinous, putrid,
fruit, and ethereal. .

Crocker (1948) stated that the flavor of cooked.meat arises from
the chemical changes occuring in the fiber. Kramlich and Pearson (1958)
reported that the water soluble fraction contained large portions of
cooked and raw beef flavor. Later (1959) they separated the volatile
components from cooked meat and identified carbon dioxide, methyl mercap-
tan, acetone, acetaldehyde, methyl sulfide and water. Similar results
were obtained by Bender and Ballance (1961), Hornstein ggual. (1960),
and Yueh and Strong (1960). Ockerman §t_§l, (1964) isolated volatile
compounds from dry-cured hams by gas chromatography retention times and
further verified the compounds by infrared spectroscopy. These compounds
were formaldehyde, acetaldehyde, propionaldehyde, isobutylaldehyde,
n-valeraldehyde, isovaleraldehyde, acetone, diacetyl, methyl ethyl ketone,
fonmic acide, acetic acid, propionic acid, butyric acid, and isocaproic
acid. They also identified hydrogen sulfide and trace amounts of disulfides
and/or monosulfides by selective trapping.

More recently, Cross and Ziegler (1965) compared some of the
volatile components of cooked hams, both cured and uncured. The examin-
ation of the volatile compounds of uncured ham by gas chromatography
showed that appreciable quantities of hexanal and valeraldehyde were
present in the uncured product. These compounds were barely detectable

in the volatile compounds of the cured meat.

Taste Panel Methodology

 

According to Caul (1957), the trained taster was first employed

in the wine, tea and coffee industries. Primarily he rates the quality

 

14

of his products. Boggs and Hanson (1949) suggested that the trained
taster should be used for detecting differences in flavor. Thurstone
(1950) agreed with the previous work. He stated that a large group of
untrained tasters is best for preference tests and a small group of
trained tasters is best for difference tests.

Caul (1957) stated that the use of difference tests presupposes
a thorough knowledge, on the part of the person conducting the test, of
flavor in general, and of the flavor of the products under test° Having
such knowledge, he can determine if the products are merely different
and/or in what respect they differ. Amerine 33 El: (1965) illustrated
5 methods of difference tests. They are single-stimulus, paired-stimuli,
duo-trio, triangle, and.multi-sample tests.

The triangle and paired tests were compared by Dawson and Dochterman
(1951). They found that there were no differences in obtaining correct
answers between these two tests. Therefore, they concluded that the two
tests were equal in their precision as a basis for selecting reliable panel
members. However, the triangle test can eliminate judges who cannot iden-‘
tify duplicate samples. Byer and.Abrams (1953) also compared the two
methods. Differing concentrations of quinine or dextrose were used in
their experiment. Their statistical results showed that the paired test
gave more clear-cut evidence of a taste difference than the triangular
test. In quality judgments the paired test also achieved higher signifi-

cance than the triangular test.

EXPERIMENTAL PROCEDURES

Samples
Paired pork samples from the right and left Longissimus dorsi

 

muscle were used in.this study. The samples were either from the 10th
to the last rib portion or from thelast rib to the last lumbar vertebra
section. The samples were frozen and stored at 0°F. until needed. One
day before the curing process, the samples were thawed at 38° F. After
thawing, the samples were weighed and placed in Cry-O-Vac bags in which
the meats were cured. 7

Curing and Curing Yields

 

Stock pickles of the desired concentrations of sodium.Chloride
and sugar were equally divided into two parts. Sodium.nitrite was added
to one of the parts. One of the paired samples was cured in the pickle
containing sodium nitrite. The other sample was cured in the pickle con-
taining no sodium nitrite. Left and right samples were cured alternately
in the pickle containing nitrite. The curing pickle to sample ratio was
always 2:1 (w/w). The meat was allowed to cure 3 days at 36-40°F. The
position of Cry-O-Vac bags was changed every day.

The concentration of sugar in the pickle was always 1.2% where it
was used. The concentration of nitrite in the pickle containing nitrite
was always 300 ppm. Two levels of sodium chloride used in the pickles
were 4.70% and 2.35%. The composition of pickles used throughout this
experiment is summarized in Appendix IV.

.After curing, the samples were again weighed to determine per cent
change during curing. Weight change during curing was calculated by divid-

ing the weight gained during curing by the weight before curing.
15

16

Cooking

The cured.meats were cooked in a 350°F. electric oven to an internal
temperature of 185°F. The external fat was removed (after cooking in all
samples except samples 1 and 2). The samples were sliced with a Hobart

meat slicer to a thickness of 5 mm.

Smoking '1
After cooking and slicing the samples, the samples were placed ”

on a 1/2 inch wire mesh screen on a rack in the smoking chamber. This

 

arrangement was used to provide unifOrm distribution of smoke on all "
‘sides of each piece. The samples were smoked for 10 minutes. During
the smoking process the temperature was 128°F. and relative humidity was

34%.

Panel Presentation

 

Each slice of meat was cut into 3 pieces. The samples were ran-
domized and coded for the triangle panel test. The triangle tests were
carried out with samples No. 1 through No. 5 under red light to mask
color differences. In each test, panel members were given three samples,
two of which were the same and one different. Figure 3 shows the quest-
ionnaire used in this test.

Name Plate No. Date

 

 

Two of these samples are identical and the other different. Please
check the different sample. Disregard tenderness. Consider flavor only.

Sample Different Sample (indicate by /)

Figure 3. Example of questionnaire used in triangle test.

17

For the remainder of the panel tests, the tasters were blindfolded.
Both paired and triangle tests were carried out, but only the paired test
was used with samples 9, 10, and 11. In the paired test, the tasters were
asked to indicate the sample which had more cured flavor. The samples

were presented to panelists according to the plan shown in Figure 4.

Panelist Order of Serving Order of Serving
Triangle Paired
l w(a) w w/o(b) W’ w/o
2 w w/o w w/o w
3 w/o w W’ w w/o
4 w/o w/o w w/o w
5 w/o w w/o w W/0
6 w w/o w/o w/o w
7 w w/o w/o w/o w
(a) with nitrite

without nitrite

(b)
Figure 4. Order of sample presentation

Statistical’Analyses

 

The data obtained from the triangle and the paired tests were
evaluated using the table taken from Bengtsson, R. (1953) in Guide

Book For Sensory Testing (1961) (See Appendix I).

 

Chemical.Analyses

Samples: Deionized distilled water was used throughout the study
unless otherwise indicated. The samples fer chemical analyses were always

obtained from.the middle section of the Longissimus dorsi after cooking

 

and trimming the fat. Each sample was ground twice through a meat grinder
(2mm_plate).

Meisture: Meisture was determined according to the method described

18

in A.O.A.C. (1965). Five g. of sample were placed in an aluminum foil
dish and dried to a constant weight fer 24 hours at 100°C. The moisture
content was calculated using the following formula:

9H O =.Original sample wt. - sample wt. after drying“x 100
° 2 *Original sample wt.

Ether Extract: The dried sample used in the moisture analysis

 

was placed in an extraction thimble. The fat was extracted with anhy-
drous ether for 3 1/2 hours in a Goldfisch Fat Extractor. The ether extract
was calculated using the following fermula:

Wt. of fat extracted

Original sample wt.x 100

% Ether Extract =

 

'Sugap: Determination of glucose was first carried out by the
method described by Folin and.Wu (1920). One g. of meat was placed in
a 25 ml. centrifuge tube. Ten and one-half ml. of water and 6.4 ml.
of 0.2 N. sulfuric acid were then added. .After 2 minutes of standing at
room.temperature, 2 ml. of 10% sodium tungstate was added slowly with
shaking. After setting for 5 minutes, the tube was centrifuged at a
speed of 2,800 r.p.m. fer 5 minutes.

Folin-Wu tubes were used for color development. Two ml. of
Folin's copper reagent were added to 2 ml. of the aliquot and.placed in
boiling water fOr 8 minutes. The tube was then cooled in running tap
water and 2 ml. of phosphomolybdic acid were added. .Again the tube was
placed in boiling water fer 2 minutes and then diluted to 25 ml. with
water. The optical density was read against a reagent blank at 420 mu,
with a Bausch and Lomb Spectronic 20 spectrOphotometer. Using a standard
glucose solution which most closely matched the unknown, the concentration
of glucose was calculated.

The sucrose in the sample was inverted by the method described by

Harrow eE_§l. (1955). One g. of the sample was placed in a test tube

19
containing 10 ml. of water. Two drops of concentrated sulfuric acid
were added. After 3 minutes the solution was neutralized with saturated
sodium carbonate solution, using litmus as the indicator. Then the
amount of glucose was determined using the method previously described.

The amount of sugar in the meat was determined as the difference
obtained by subtracting the amount of glucose before inversion from the
total amount of glucose in the sample after inversion.

.Saltz The sodium chloride content was determined by the Vblhard _
method as outlined in A.O.A.C. (1965). Three g. of meat were placed in
a 300 ml. Erlenmeyer flask. Fifty ml. of 0.1 N. silver nitrate were
added to precipitate all chloride and to leave an excess of silver
nitrate. After adding 15 ml. of concentrated nitric acid, the solution
was mixed and boiled until all the meat disintegrated. During boiling
5% potassium permanganate was added, a few drops at a time, until a few
ml. had been added. .After boiling, the solution was diluted to approx-
imately 150 ml. with water. Then 25 ml. of diethyl ether were added to
coat the silver chloride. Five ml. of ferric indicator [Fe NH4 (504)2
lZHZO] and 5 ml. of a 1:1 solution of nitric acid and water were added.
Excess silver was then titrated with potassium thiocynate until a permanent
light brown color appeared. From the volume (ml.) of silver nitrate used,

the quantity of chloride was calculated using the following formula:

Hfl. of 0.1 N. AgNOIX 0.58
sample wt. “

Nitrite: The nitrite content was determined by the procedures

%NaCl =

 

outlined in A.O.A.C. (1965). Five g. of the meat sample were placed in
a 500 ml. volumetric flask. Approximately 300 ml. of warm water (80°C.)
were added. The flask was placed in a steam bath for 2 hours with occasion-

al shaking. Five m1. of a saturated mercuric chloride solution were added

 

20

immediately after removal from the steam.bath and the resulting solution
mixed thoroughly. The solution was cooled to room temperature, brought
to volume with water, and filtered through 888 #560 filterpaper. Ten
ml. of the filtrate were added to 2 ml. of Griess reagent in a 50 ml.
volumetric flask. The optical density was obtained at 520 mu. using a
Beckmann D.U. spectrophotometer. The nitrite content was determined by
comparison with a standard nitrite curve.

Protein: The Kjeldahl method outlined in A.O.A.C. (1965) was
used to determine protein content. One-half g. of the meat sample was

weighed on N free parchment paper squares. The paper was placed in a

 

digestion flask. One-half g. of sodium sulfate, 1 ml. of 10% copper
sulfate, 7 m1. of concentrated sulfuric acid and.one glass bead were
added to the flask. The flask was boiled with occasional swirling until
the solution cleared. The flask was cooled and water was added to about
the middle of the lower bulb of the flask. The flask was then connected
to distilling equipment. After adding approximately 5 ml. of cold 40%
NaOH, the distillate was collected in a 125 ml. Erlenmeyer flask containing‘
10 m1. of 2% boric acid and several drops of bromo-cresol-green indicator.
The distillation period was 7 minutes while the tip of the condenser was
beneath the surface of the boric acid and 4 minutes while the tip of the
condenser was above the surface. The excess boric acid was back titrated
with 0.1 N. sulfuric acid. The protein content was calculated using the

following formula:

N. of acid x 14 x 6.25 x ml. of acid
wt. of sample

 

% protein =
Phenol: The estimation of total phenols was made by the colori-
metric method of Tucker (1942). Twelve and one-half g. of the meat were

blended for 5 minutes with 50 ml. of 1:1 alcohol water solution. The

21
solution was filtered through 588 #560 filterpaper. After 24 hours
storage at 38°F. the filtrate was refiltered through Whatman No. 2 filter-
paper at the same temperature. Twelve and one-half ml. of the filtrate
were diluted to 25 ml. with water. Five ml. aliquot of the sample was
pipetted into a 15 x 180 mm. test tube. Five ml. of 0.5% sodium borate
buffer and 1 m1. of N, 2, 6-Trichloro-p-benzoquinoneimine were added to
the tube. The tube was shaken and then allowed to stand for 1 hour at
room temperature to allow for color development. The colored complex

was extracted from the aqueous solution with 15 ml. of n-butanol in a

 

small separatory fUnnel. The butanol layer was transferred into a 25

 

ml. graduated test tube and the volume increased to 21 ml. with n-butanol.
Two ml. of n-butanol saturated with ammonia were then added, and after
mixing by shaking, its optical density was read against a reagent blank
at 635 mu. on a Bausch and Lomb Spectronic 20 spectrophotometer. The
estimation of total phenols (mg./100g.) in the collected solution was

obtained with the phenol standard curve.

EXPERIMENTAL RESULTS AND DISCUSSION

Effect of Nitrite on Cured Flavor of Pork

 

The major portion of this study was undertaken to determine if
nitrite has an effect on the cured flavor of pork. A study was initiated
using 300 ppm of sodium nitrite in the pickle as the only variable.

Table 1 shows the composition of the pickle used in paired samples 1
through 5.

Table 1. Composition of the pickle used in the paired samples 1 - 5.

Paired Sample Sodium Chloride Sugar Sodium.Nitrite*
Right 4.70% 1.2% 300 ppm
Left 4.70% 1.2% .......

*Sodium nitrite was added to left and right samples alternately.

After cooking, the color of the samples was compared to insure
uniform distribution of sodium.nitrite.“ A pink color was uniformly pre-
valent throughout the meat cured with nitrite. No pink color was observed
in the meat cured without sodium nitrite.: No nitrite burn was observed.

Triangle taste tests were carried out under a red light to mask
the color difference between the meat containing sodium.nitrite and the
one containing no sodium nitrite.* Eighteen untrained panelists partici-
pated in the taste panel tests. The data collected from this taste panel
were analyzed using the table in Appendix I. The results of the taste
panel and the statistical analysis of the data are summarized in Table
2.

22

23

Table 2. Results of statistical analyses of the data obtained from
the triangle taste test.

No. of panelists who

Trials- No. of Panelists identified different sample Significance
1 l8 ' 9 n.s. [a]
2 l8 7 n.s.
3 18 12 **
4 18 10 *
5 18 12 **
* P<0.05 [a] not significant
** P<0.01

In trials 1 and 2 external fat was not removed prior to the taste

 

panel. The results of the triangle tests showed that fewer than a signi-
ficant number of panelists were able to select the different sample. In
the trials 3, 4, and 5 external fat was removed before the taste panel
tests were carried out. This time, the results of the triangle tests
were significant. Panelists were able to identify the different sample
in the triangle taste tests at-a statistically significant level.

7 To determine whether the panelists distinguished the difference
between samples because of the saltiness in the triangle test, paired
tests were carried out using the same samples used in the triangle test.
The panelists were asked to indicate the saltier sample. No significant
difference in saltiness betweenthe two samples was noted.

Further studies were initiated to confirm that sodium nitrite
affected cured flavor. Panelists were blindfolded to insure that the
judgment in the tests was not influenced by the color of the meat. The
concentration of sodium chloride in the pickle was decreased from 4.70%
to 2.35%. The results of the triangle tests and the paired tests are
summarized in Table 3. The results of the triangle tests show that panel-
ists were able to identify the different sample at a statistically signi-

ficant level in the triangle taste tests.

24

Table 3. Results of statistical analysis of the data obtained from
the triangle taste tests and paired taste tests.

Triangle# Paired##
Trial No. of panelists taste test Significance taste test Significance
6 18 ' ‘ 11 * 15 **
7 18 10 * l4 *
8 36 21 ** 32 ***
#No. of panelists who identified the different sample * P<0.05
##No. of panelists who chose the sample containing ** P<9.01
NaNO2 as having more cured flavor ***P<0.001

As Table 3-shows, a statistically significant number of panelists
chose the sample containing sodium nitrite as having more cured flavor.

To determine whether the judgment in the paired tests was based
on saltiness, the following experiment was carried out. The concentration
of sodium chloride was doubled in the pickle containing no sodium nitrite.

The composition of the pickle used was as follows:

Table 4. Composition of the pickle used in paired samples 9, 10, and 11.

Paired sample Sodium chloride ' Sugar Sodium.Nitrite*
Right 2.35% 1.2% 300 ppm
Left . 4.70% 1.2% -------

.*Sodium nitrite was added to left and right alternatively.

The panelists were blindfolded and asked to indicate the sample
having more cured flavor. The results of the taste panel tests are summar-
ized in Table 5.

Even though no statistical significance was found in these paired
tests, a larger number of panelists selected the sample containing sodium
nitrite as having nore cured flavor despite the fact that the sample was

less salty. These results indicated that saltiness was not the only factor

 

25

responsible fer the production of the cured flavor of pork. Obviously,

sodium nitrite, as well as salt, contributes to cured flavor.

Table 5. Results of statistical analyses of the data obtained
from.the paired-taste—tests (9, 10, 8 ll).

Trials No. of panelists No. of panelists# Significance
9 . 36 21 n.s.[a]
10 36 . 23 n.s.
ll 36 20 n.s.
#No. of panelists who chose the sample [a] not significant

containing sodium nitrite as having

more cured flavor.

An attempt was made to determine whether sodium nitrite brings
about some change in the flavor of pork without the influence of salt
and sugar.~ This trial was not designed to isolate or characterize the
factors responsible for the production of the cured flavor by sodium. A”
nitrite. Neither sugar nor salt was used in the curing process. Sodium
nitrite was the only variable in the curing pickle. One of the paired
pork samples was cured in deionized distilled water containing 300 ppm
of sodium nitrite as the sole curing agent and the other was cured in
deionized distilled.water. Table 6 gives the results of the triangle and
paired taste tests.

Table 6. Results of statistical analyses of the data obtained from
the triangle and paired taste tests.

Triangle# Paired##
Trials No. of panelists taste test Significance taste test Significance
12 23 14 ** 19 '**
13 19 11 ’* 16 *
14 18 ll * 14 t
# No. of panelists who identified the * P<0.05
different sample. **P<0.01

##No. of panelists who chose the sample
with NaNO2 as having more cured flavor.

 

 

26

The results of the triangle taste tests showed that the panelists
identified the different sample at a statistically significant level.
In paired taste tests a significant number of panelists chose the sample
containing sodium nitrite. These results indicated that the sodium
nitrite causes some change in flavor of pork without the influence of

salt and sugar.

It was interesting to note the-performance of the panelists in I;
the taste panel tests. .As pointed out by MTak.EE”§1° (1959) and Baker ‘7'
33 El: (1961), some panelists were very Sensitive in distinguishing the

 

different sample in the triangle tests and.others were very insensitive. I'L
Some panelists were actually unable to distinguish the difference between

the samples containing sodium nitrite.and those containing no sodium

nitrite. The author's opinion is that results can be obtained at a

higher significant level if panelists.are previously trained fer the

purpose of this experiment.. This.statement is supported by Boggs and

Hanson (1949). They suggested that the trained taster should be used

for detecting differences in flavor.

Effect 9f Smoking gg_the Cured Flavor of Pork Due to Nitrite

 

- ’ -

The samples were cured in the pickle in which sodium.nitrite was
the only variable. The samples.were.cooked and smoked. The results of
the statistical analyses of the data obtained from the taste panel tests
are shown in Table 7. .As the results in Table 7 indicate, the panelists
were able to identify the different sample in the triangle test at a
highly significant level, even though both samples were smoked. These
results indicated that smoking did not affect the ability of the panelists

to identify the different sample in the triangle taste tests.

27

Table 7. Results of statistical analyses of the data obtained
from the triangle and paired taste tests.

Triangle# Paired##
Trials No. of panelists taste tests Significance taste test Significance
15 26 17 *** 22 ***
16 22 14 ** l8 **
17 18 13 *** l7 ***
# No. of panelists who identified the **P<0.01
different sample. ***P<0.001

##No. of panelists who chose the sample
containing NaNO2 as having more cured flavor.

In the paired tests, panelists chose the sample containing sodium
nitrite as having more cured flavor at a highly significant level. Thus,
smoking may not affect the flavor constituent produced by the action of
sodium nitrite on pork.

Weigh£_Change DuringCuring|

Changes in weight during curing were observed. In all cases,
there was a weight increase during the curing (Appendix II). The weight
gained during the curing varied from 5.00% to 18.80%.

There are many factors that could affect weight changes during
curing. One of the most important factors is the physical state of the
meat. Lewis (1966) pointed out that meat, in which the structure was
watery, had a poorer absorption of salt compared with normal meat. The
weight of brine absorbed was about 7% in the former whereas it was 40% in
the latter. The temperature of the curing room may also effect the
weight change during curing. The rate of diffusion of the curing ingred-
ients can be greatly facilitated by increasing the temperature. However,
if the temperature is too high, bacterial spoilage may result (Amer. Meat

Inst. Found., 1960). MOulton and Lewis (1940) claimed that bacterial

28-

spoilage increased if the temperature of the curing room was raised

above 40°F.

Chemical Analysis

 

The purpose of the chemiCal analyses was to compare the concen—
trations of thecuring ingredients within the paired samples. ‘The effect
of the difference in the concentration on the judgment of the panelists
was determined. ~

Representative paired samples taken from the center section of
the cooked sample were analyzed. Appendix III gives the results of the
chemical analyses.

.A paired taste test was used to determine whether the panelists
could detect a variation of 0.18% salt concentration at 2%, and 0.08%
salt concentration at 1% salt levels in the cooked meat. The results
obtained indicated that the panelists could not significantly differen-
tiate either of the two levels (Tables 8, 9). Therefore, their flavor
evaluation was not based on saltiness.

Table 8. Results of statistical analyses of the data obtained from
the paired taste tests (meat containing 2% sodium chloride).

Paired % Sodium No. of#. No. of## No. of### _
samples Chloride apanelists panelists ' panelists Significance

1R[1] 2.11

 

 

 

 

 

1L[2] 2.20 4 7 1 11.5.51
3.5 3:32 . 5 7_ . ..
ii 3:83 5 9 s n.s.
25 13% 4 8 . . .
ii 12:13; 7 2 9 n.s.

Note: See bottom of Table 9 for code.

29

Table 9. Results of statistical analyses of the data obtained
from.the paired taste tests (meat containing 1%
sodium.chloride).

 

 

 

 

Paired % Sodium. No. of# No. of## No. of###
samples Chloride panelists panelists panelists Significance
1]
6R[ 1.01 3
6L[2] 1.08 7 2 9 n.s.[ ]
35' i'ii 7 4 7 n.s
8R 0.95
8L 1.08 11 15 10' n.s.
[1] right # Indicated there was no difference in saltiness
[2] left ## Chose R sample as being saltier

[3] not significant ### Chose L sample as being saltier

Sugar analyses showed that the highest concentration of sugar in
the cured meat was 0.35% (Appendix III). IMills 22 31° (1960) stated
that the threshold level of sugar fOr detection of sweetness in hams
appeared to be 0.5%~0.75%., Since 0.35% of sugar is less than the reported
threshold level, apparently the concentration of sugar did not affect the
panelist's judgment in the taste tests.

Difference in phenol content between the paired samples ranged
from.0.19ppm to 0.26ppm.' It is doubtful if the panelists were able to
detect such a small difference in phenol content. Results showed that
panelists chose the samples containing sodium nitrite and less phenol
content as having a more cured flavor than the samples containing no=
sodium nitrite and a higher phenol content (Table 10). These results
seem.to suggest that the phenol content probably did not influence the

judgment of the taste panel.

30

Table 10. Results of statistical analyses of the data obtained from
the paired taste tests (smoked sample).

Paired Sodium No. of No. of#

samples Phenols(ppm) nitrite(ppm) panelists panelists Significance
[l]

1112] :1: 22 22 22

16R 9.11 **

16L 9.34 19 22 18

17R 6.38 ***

17L 6.02 26 18 17

[1] right **P<0.01

[2] left ***P<0.001

# Chose the sample containing sodium nitrite as having more cured flavor.
The cooked samples were also analyzed fer moisture, fat and protein

to observe the diversity of the biological system (Appendix III). The
results obtained from.an analysis of variance showed no significant

difference in moisture, fat and protein between the right and left

samples. These results indicated that the moisture, fat and protein
content of the samples did not influence the judgment of the panelists
in the triangle and paired taste tests. However, there was a signifi-

cant difference in moisture, fat and Irotein between sample pairs.

SUMMARY AND CONCLUSIONS

The experimental work described strongly indicates that sodium
nitrite contributes to the cured flavor of'pork. Sodium nitrite alone,
'without the influence of salt and sugar, reacts with constituents of the
tissue, either during curing or during cooking to produce a certain
flavor. Characterization of the flavor and identification of the flavor
constituents produced by the action of sodium nitrite on pork remain to
be determined.

Even though both samples, the sample containing sodium nitrite
and the sample containing no sodium nitrite, were smoked, panelists were
still able to identify the different sample in the triangle taste tests.
In the paired taste tests using the samples as above, a statistically
significant number of panelists chose the sample containing sodium nitrite
as having more cured flavor. Therefore, smoking may not have any effect
on the flavor produced by sodium nitrite in pork.

It was observed that some panelists were very accurate and con-
sistent in identifying the different sample in the triangle taste test,

whereas some were actually unable to identify the different sample.

31

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35

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APPENDIX I-
TABLE OF SIGNIFICANCE LEVELS OF TASTE-TEST RESULTS

 

 

 

 

 

TWO SAMPLE TEST TRIANGLE TEST
No. of Concurring Choices No. of Concurring Choices
No. of Necessary Necessary No. of
Tasters to Establish Significance to Establish Significance Tasters
1a: 11nt_________zx: : :1. 1x2: 9
l -- -- -- -1 -- -- l
2 -- -- -- -- -- -- 2
3 -- -- -- 3 -- -- 3
4 -- -- -- 4 -- -- 4
5 -- -- -- 5 5 -- 5
6 6 -- -- 5 6 -- 6 tuwa
7 7 -- -- 5 6 7 ‘7 i
8 8 8 -- 6 7 8 8' I
9 8 9 —- 6 7 8 9
10 9 10 -- 7 8 9 10
11 10 ll 11 7 8 10 ll
12 10 ll 12 8 9 10 12
13 11 12 13 8 9 ll 13
14 12 13 14 9 10 ll 14
15 12 13 14 9 10 12 15
16 13 14 15 9 11 12 l6
17 13 15 16 10 ll l3 17
18 14 15 17 10 12 13 18
19 15 l6 17 ll 13 14 19
20 15 l7 18 11 13 14 20
21 l6 17 19 12 13 15 21
22 17 ' 18~ 19' 12 - 14 15 22
23 17 ‘ .19~ 20 12 14 ll 23
24 18 19 21 13 15 16 24
25 18 20 21 13 15 17 25
26~ 19 20 22 14 15 17 26
27 20 21 23 l4 16 18 27
28 20 22 23 15 16 18 ‘28
29 21 22- 24 15 17 19 29
30 21 23 25 15 17 19 30
31 22 24 25 l6 18 20 31
32 23 24 27 16 18 20 32
33 23 25 27 17 18 21 33
34 24 25 27 17 19 21 34
35 24 26 28 17 19 22 35
36 25 27 29 18 20 22 36

*Significant (above the 5% level of probability).
**Highly significant (above the 1% level of probability).
***Very highly significant (above the 01.% level of probability).

3?

 

APPENDIX 11
WEIGHT CHANGE DURING CURING

Wt. befbre Wt. after
Paired sample curing (lbs.) curing (lbs.) Yields(%)
1R 1.60 1.80 12.50
1L 1.40 1.60 14.30
2R 1.70 1.90 17.60
2L 1.70 1.90 17.60
3R 1.60 1.80 12.50
3L 2.00 2.20 10.00
4R 1.80 2.00 11.10
4L 1.40 1.60 14.30
5R 0.80 0.95 18.80
5L 1.00 1.18 11.80
6R 1.80 2.00 11.11
6L 2.40 2.60 *8.33
7R 1.10 1.25 13.65
7L 1.20 1.40 16.66
8R 1.80 2.00 11.11
8L 1.80 2.00 11.11
9R 1.60 1.70 6.25
9L 1.50 1.60 6.67
10R 1.80 1.90 5.55
10L 1.80 1.90 5.55
11R 1.80 1.90 5.55
11L 1.80 1.90 5.55
12R 1.40 1.50 7.14
12L 1.00 1.05 5.00
13R 1.60 1.80 12.50
13L 1.60 1.80 12.50
14R 1.60 1.80 12.50
14L 1.60 1.80 12.50
15R 2.00 2.20 10.00
15L 1.80 2.00 11.11
16R 1.80 2.00 11.11
16L 1.60 1.80 12.50
17R 1.80 2.00 11.11
17L 2.00 2.20 10.00

38

 

APPENDIX III
CONCENTRATIONS OF CURING INGREDIENTS IN COOKED SAMPLES

 

39.

Paired % Sodium Nitrite Phenol

Sample Chloride % Sugar (ppm) ~(ppm) %;MOisture % Protein % Fat
1R 2.11 0.20 37.75 26.01 7.22
1L 2.20 0.22 37 36.44 25.78 ' 7.65
2R 2.08 0.24 32 37.16 25.78 6.88
2L 2.26 0.19 36.18 25.24 6.73
3R 2.09 0.25 40.75 27.99 6.41
3L 2.02 0.25 41 39.96 28.93 6.87
4R 1.72 0.09 30 50.02 33.80 9.09
4L 1. 0.09 50.39 34.93 8.80
5R 1. 0.11 53.12 36.08 8.00
5L 1. 0.10 30 50.66 38.15 7.71
6R 1. 0.22 43.21 27.08 7.27
6L 1. 0.25, 39 40.98 31.90 6.96
7R 1 0.30 42 51.01 37.95 6.87
7L 1. 0.28 53.47 39.27 6.97
8R 0. 0.31 19 53.66 33.02 ‘6.78
8L 1 0.26 53.28 33.67 7.11
9R 1 ‘ 0.16 39 49.70 28.54 ‘6.81
9L 2 0.19 55.55 ' 29.40 6.34
10R 2. -0.14 55.95 26.95 '6.63
10L 1 0.16 35 54.09 28.27 6.47
11R. 1 0.15 38 52.71 29.01 7.35
11L 2 0.14 2 54.76 30.66 7.17
12R 23 48.57 28.60 7.74
12L 51.00 27.99 7.45
13R 55.01 ~33.48 7.10
13L 22 52.62 33.80 8.94
14R 22 58.00 29.46 9.17
14L 59.33 30.85 8.40
15R 0.35 32 3.12 55.54 28.67 8.63
15L 0.31 3.31 59.30 29.23 7.97
16R 0.31 9.11 55.09 31.88 9.31
16L 0.34 19 9.34 56.42 28.65 7.98
17R 0.21 ‘ 6.38 54.25 36.38 5.82
17L 0.29 26 6.02 51.63 36.03 5.86

APPENDIX IV

COMPOSITION OF PICKLES

Paired % Sodium . Nitrite
Samples Chloride % Sugar (ppm) Smoked

1R 4.70 1.2 0

1L 4.70. 1.2 300

2R 4.70 1.2 300

2L 4.70 1.2 0

3R 4.70 1.2 0

3L 4.70 1.2 300

4R 4.70 1.2 300

4L 4.70 1.2 0

5R 4.70 1.2 0

5L 4.70 1.2 300

6R 2.35 1.2 0

6L 2.35 1.2 300

7R 2.35 1.2 300

7L 2.35 1.2 0

8R 2.35 1.2 300

8L 2.35 1.2 0

9R 2.35 1.2 300

9L 4.70 1.2 0

10R 4.70 1.2 0

10L 2.35 1.2 300
11R 2.35 1.2 300
11L 4.70 1.2 0
12R 300

12L 0
13R 0
13L 300
14R 300
14L 0
15R 2.35 1.2 300 yes
ISL 2.35 1.2 0 yes
16R 2.35 1.2 0 yes
16L 2.35 1.2 300 yes
17R 2.35 1.2 0 yes
17L 2.35 1.2 300 yes

40

 

   

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