COMPARISON OF SURIMI AND SOLUBILIZED SURIMI FOR JILL …
Transcript of COMPARISON OF SURIMI AND SOLUBILIZED SURIMI FOR JILL …
COMPARISON OF SURIMI A N D SOLUBILIZED SURIMI FOR K A M A B O K O PRODUCTION FROM F A R M E D CHINOOK S A L M O N
By
JILL MARIE RICHARDSON
B.Sc, The University of Alberta, 1993
A THESIS SUBMITTED IN PARTIAL F U L F I L L M E N T OF
THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE
In
THE F A C U L T Y OF G R A D U A T E STUDIES
(Department of Food Science)
We accept this thesis as conforming to the required standard
THE UNIVERSITY OF BRITISH C O L U M B I A
April 1999
©Jill Marie Richardson, 1999
I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an advanced degree a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I ag r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e head o f my department o r by h i s o r h e r r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n .
Department o f Food Science. The U n i v e r s i t y o f B r i t i s h C o l umbia V a n c o u v e r , Canada
Date vTun^ /b. /Qtytf^B) -;
Abstract
The thesis hypothesis of this research was that farmed chinook salmon could be made
into better quality functional kamaboko when made from solubilized frozen surimi than
when made from conventional frozen surimi.
An 84 day storage study compared kamaboko gel quality made from solubilized and
traditional surimi. Fresh farmed chinook salmon (Oncorhynchus tshawytscha) was used
to make both solubilized surimi and surimi (control). Solubilized treatments contained
varying concentrations of calcium chloride, sodium chloride and water. The Random
Centroid Optimization (RCO) program randomly generated concentration values of
additives. All surimi treatments (solubilized and control) contained 8.3%
cryoprotectants. Treatments were taken from storage on days 3, 7, 14, 28, 56 and 84
from an -8°C freezer and made into kamaboko. Solubilized treatments were diluted after
frozen storage and then centrifuged to constant moisture content.
All kamaboko gels had respective moisture, protein, crude fat and ash contents of 74.5 +
5.5%, 13.6 ± 1.7%, 4.4 + 2.4%, and 5.6 ± 3.1%. Salts added to solubilized treatments
influenced ash content. No proximate analysis trends were observed between treatments
during the storage study. Variation in protein and water concentrations within the range
of this study did not appear to affect overall kamaboko quality.
i i
Treatments had similar Hunter "L", "a", "b" values and values remained relatively
consistent over the storage study. The TA-TXT2 Texture Analyzer was used to conduct
punch tests. A 6 point fold test scale was employed to evaluate kamaboko elasticity.
ANOVA suggested that gel strengths and fold test scores did not change over time, but
treatments were significantly different (p < 0.05).
All factors (sodium chloride, calcium chloride, and dilution) proved significant (P < 0.05)
in contributing to the treatment effect using multiple regression. However, sodium
chloride and calcium chloride had a larger impact than the dilution factor on gel strength
and fold test scores. Although, treatments were not significantly different on different
days of the storage study, treatment 7 was clearly the best treatment when compared to
the control and other treatment gel strengths and fold test scores.
Each kamaboko treatment (before cooking) for each storage day was examined by SDS-
PAGE. Variations in gel strength were consistent with degradation in the myosin heavy
chains of the SDS-PAGE Phast gels. Lower gel strengths were observed in treatments
that had more degradation of the myosin heavy chain.
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Table of Contents
Abstract ii
Table of Contents iv
List of Tables viii
List of Figures ix
Acknowledgments x
Chapter 1: Introduction 1
1.1 Definition of surimi 1
1.2 Historical background of surimi 2
1.3 Surimi products 4
1.4 Species used for surimi production 5
1.5 The modern surimi process 6
1.5.1 Sorting and cleaning 7
1.5.2 Filleting 7
1.5.3 Separation of meat 8
1.5.4 Leaching 8
1.5.5 Intermediate dewatering 9
1.5.6 Refiner 10
1.5.7 Final dewatering and the importance of pH 11
1.5.8 Blending 1 11
1.6 Cryoprotectants 12
1.7 Solubilization 13
iv
1.8 Kamaboko making 15
1.9 Surimi quality 15
1.10 Rheological properties of surimi gels 16
1.10.1 Effect offish freshness, rigor condition, seasonality 16
1.10.2 Effect of chopping temperatures 17
1.10.3 Effect of moisture content 17
1.10.4 Effect of functional additives 18
1.10.5 Effect of storage temperature 18
1.10.6 Effect of low temperature setting 19
1.10.7 Effect of refrigerated storage on gels prior to evaluation 19
1.10. Effect of test temperatures 19
1.11 Random Centroid Optimization 20
1.12 Compositional aspects of surimi processing 20
1.12.1 Lipids in fish 20
1.12.2 Proteins 21
1.12.2.a Sarcoplasmic proteins 21
1.12.2.b Myofibrillar proteins 22
1.12.2.C Connective tissue 23
1.13 Thesis hypothesis 23
Chapter 2: Materials and Methodology 42
2.1 Optimization of surimi treatments using RCO 42
2.2 Surimi production 42
V
2.2.1 Fish source 42
2.2.2 Filleting 43
2.2.3 Grinding 43
2.2.4 Leaching 43
2.2.5 Dewatering 45
2.3 Surimi solubilization 45
2.4 Kamaboko making 47
2.5 Compositional evaluation of kamaboko 49
2.5.1 Moisture determination (oven method) 5 0
2.5.1.2 Moisture determination (microwave method) 50
2.5.2 Crude fat determination 50
2.5.3 Protein determination 51
2.5.4 Ash determination 51
2.6 Sample preparation 51
2.7 Functional evaluation of kamaboko 52
2.7.1 Color 52
2.7.2 Gel strength 52
2.7.3 Fold test , 53
2.7.4 SDS-PAGE electrophoresis 53
2.8 Statistical analysis 55
Chapter 3: Results and Discussion
3.1 Compositional evaluation results of kamaboko
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58
58
3.1.1 Crude protein content 5 8
3.1.2 Moisture content 59
3.1.3 Crude fat content 61
3.1.4 Ash content 62
3.1.5 pH 63
3.2 Functional evaluation results of kamaboko 64
3.2.1 Color 64
3.2.2 Gel strength 65
3.2.3 Fold test scores 66
3.2.4 SDS-PAGE electrophoresis 67
Chapter 4: Conclusion and future recommendations
4.1 Conclusion and future recommendations 79
Bibliography 81
V l l
List of Tables
Table 1. Nine solubilized treatments and the control 56
Table 2. Fold test scale 57
Table 3. Crude protein fraction in kamaboko gel (wet basis, n =3) 68
Table 4. Moisture fraction in kamaboko gels (wet basis, n = 3) 69
Table 5. Fat and ash fractions in day 84 kamaboko gels (wet basis, n=3) 70
Table 6. Fat and ash fractions in treatment 7 kamaboko gels (wet basis, n =3) 71
Table 7. PH values of solubilized kamaboko throughout the storage study
(n =18 (3 X6 storage days)) 72
Table 8. Hunter "L", "a", "b" values of kamaboko gels (n = 5) 73
Table 9. Standard deviations of Hunter "L", "a", "b" values in kamaboko
gels (n = 5) 74
Table 10. Gel strengths (N X mm) of kamaboko gels (n = 5) 75
Table 11. Multiple R values for gel strengths and treatment factors 76
Table 12. Fold test scores df kamaboko gels (n=5) 77
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List of Figures
Figure 1. Effect of the discovery of cryoprotectants and tighter catch controls on the Japanese fishing industry during 1965-1985 25
Figure 2. Comparison of traditional and modern surimi production 26
Figure 3. Examples of surimi based products 27
Figure 4. Flow diagram of the surimi process and subsequent yield 28
Figure 5. Typical design of a surimi meat separator 29
Figure 6. Effect of agitation and water-protein contact time during leaching 30
Figure 7. Effect of ionic strength of wash water during leaching 31
Figure 8. Effect of meat: water ratio and washing cycles on the removal of 32 soluble proteins during leaching
Figure 9. Effect of pH on the water holding capacity of minced meat 33
Figure 10. Effect of wash water temperature on the efficiency of dewatering 34
Figure 11. Effect of moisture content (%) on gel strength and elasticity 35
Figure 12. Effect of functional additives on kamaboko gel strength
And elasticity 36
Figure 13. Effect of frozen storage temperature on gel strength - 37
Figure 14. Effect of refrigerated storage prior to gel strength and elasticity
evaluations 38
Figure 15. Effect of test temperature on gel strength 39
Figure 16. Schematic of myosin 40
Figure 17. Heat gelation of surimi 41
Figure 18. SDS-PAGE results 78
Acknowledgment
I would like to express my immense respect and appreciation to a wonderful
mentor, my supervisor, Dr. Durance. Throughout my studies at UBC, Dr.
Durance provided me with outstanding advice, support, and guidance. He also
tolerated my bad jokes, my stubborn ways and he supported my non-academic
pursuits (sports). For these reasons, and countless others I would like to thank
him.
I would also like to thank my committee members, the Department of Food
Science, friends and family for their exceptional support.
Finally, I would like to thank a dear friend, Peter. For without his love, support
and belief in me, I would never have entered the realm of graduate school.
Chapter 1. Introduction
Chapter 1
Introduction
1.1 Definition of surimi
Surimi is a Japanese term meaning "minced meat" (Sonu, 1986). Although surimi
can be made from both land and sea based animals, surimi is almost always
derived from fish muscle (Lanier, 1997). In simple terms, surimi is deboned,
washed, concentrated fish muscle (Lanier, 1997). It is necessary to distinguish
"minced fish", "raw surimi" and "frozen surimi". When fish flesh is separated
from bones and skin, it is called "minced fish", the starting material for surimi
production. Once minced fish is washed to remove fat and water-soluble
components, it becomes "raw surimi". "Raw surimi" is a wet concentrate of the
myofibrillar proteins of fish and possesses enhanced gel-forming, water-holding,
fat-binding, and other functional properties relative to "minced fish". However,
the myofibrillar proteins will lose their functional properties once they are frozen
(Okada, 1992). The primary properties of surimi are its long term stability in
frozen storage with cryoprotectants and its ability to form thermo-irreversible gels
(Sonu, 1986; Lanier, 1986). Because surimi can be converted to an elastic and
chewy gel, it is used as an intermediate raw material in a variety of fabricated
seafoods and other traditional products (Ma et al, 1996; Lee, 1984). For the
purpose of this thesis, surimi refers to "raw surimi" made from farmed chinook
salmon that has been mixed with cryoprotectants and frozen.
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Chapter 1. Introduction
1.2 Historical background of surimi
Commercial surimi production in Canada and the US is about 40 years old (Sonu,
1986; Okada, 1992; Lee, 1984). However, the Japanese have been making surimi
for approximately 1500 years (Sonu, 1986). Traditionally, surimi was made from
fresh fish and processed into kamaboko. Kamaboko is a generic term that refers
to a range of traditional Japanese surimi based products (Okada, 1992). For most
of surimi's long history, surimi production occurred daily and depended on the
availability of fresh fish and manual labor. In the early 1900's production
increased with the arrival of the western trawl method of fishing (Okada, 1992).
However, surimi production remained limited due to its poor shelf life. In 1959,
Nishiya's research group in Hokkaido Japan discovered sugars effectively
prolong and stabilize protein functionality in surimi during frozen storage
(Mackie, 1993; Okada, 1992; Lee, 1984). Initially, surimi contained 5% glucose.
Later sucrose and sorbitol replaced glucose at the 8-10% level to improve'stability
and to reduce Maillard browning products (Okada, 1992). This discovery enabled
industry to stockpile surimi. Production efforts moved from onshore to
mechanized offshore production and output dramatically increased (Lee, 1984).
Many more advancements in surimi technology occurred during the early 1970's
(Okada, 1992). Collaborative efforts from the Japanese surimi industry and
various research institutes laid the basis for modern surimi production. These
efforts resulted in the establishment of physical and chemical principles for surimi
production and preservation.
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Chapter 1. Introduction
More specifically, scientists discovered the following important facts:
i) Solubilization of myofibrillar proteins and crosslinking of the protein gel network is key in producing high quality surimi
ii) Gel forming ability of surimi based products is species dependent and is affected by the freshness, biological state of fish, and frozen storage treatment
iii) Surimi based products are affected by the level and type of salt, pH, and heating schedule
iv) Starches have a strong gel strengthening ability and participate in a dispersed phase, whereas protein functions in a continuous phase (Okada, 1992)
Several processing factors influence the storage stability of surimi based products.
For example, moisture content, packaging material, cooking procedures and the
use of preservatives all have impact on storage stability (Okada, 1992). Figure 1
depicts the dramatic increase in surimi production during the years following
Nishiya's discovery (Sonu, 1986). The rise in surimi production was due to the
rapid growth of the Japanese economy during these times and due to the abundant
supply of frozen surimi. A decline in surimi production began in 1974 due to an
increase in the cost of raw materials and a change in consumer perceptions. From
1974 to the present, surimi prices have almost doubled due to the water pollution
act of 1970, the oil crisis of 1974, and an increase in catch regulations by nations
controlling the pollock resource. Consumers perceptions changed as they became
concerned with food additives such as hydrogen peroxide, and nitrofuran
compounds used in surimi production (Okada, 1992).
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Chapter 1. Introduction
As the production of surimi has evolved, so has the machinery used to make it.
Equipment advancements include: fishwashers, descalers, large capacity meat
separators, washing tanks, rotary sieves, refiners, screw presses and decanters.
Fishwashers, descalers and meat separators facilitate the cleaning and isolation of
white flesh. Rotary sieves have increased leaching efficiency, while refiners have
replaced batch type dewatering processes. Decanter centrifuges recover fine
muscle particles suspended in the effluent water (Okada, 1992; Lanier et al.,
1992).
1.3 Surimi products
Surimi production peaked during the late 1960's to mid 1970's (Okada, 1992).
Production has since declined due to an increased cost in raw products due to
stricter catch controls and tighter effluent disposal regulations (Okada, 1992;
Marris, 1991). As a result, efforts to produce new products, minimize effluent,
utilize other species, attract new consumers, and find alternate ways to preserve
surimi based products are being made. Examples of surimi based product
development include: crab leg analogs, binding agents, high fiber drinks, meat
flavored analogs, and dehydrated surimi (Morris, 1988; Okada, 1992, Andres,
1987). Figure 2 depicts some of the advancements in surimi production (Okada,
1992)
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Chapter 1. Introduction
1.4 Species used for surimi production
Presently, the most popular species used for surimi production is Alaska pollock
(Theragra Chalcogramma) (Whittle and Hardy, 1992; Okada, 1992; Mackie,
1993). The volume, availability, subtle flavor, odor characteristics and low cost
of this species makes it optimal for surimi production (Roussel and Cheftel,
1988). However, the recent decline in the Alaska pollock fishery has prompted
studies on the suitability of various other fish species for surimi production (Dora
and Hiremath, 1991; Okada, 1992). Presently, industry is actively seeking more
profitable under-utilized species. Whittle and Hardy (1992) have defined under
utilized species as fish that are:
i) Available, but difficult to catch, process, or market
ii) Caught in quantity or as a by-catch and used for low value industrial products, but which could be upgraded for human consumption
iii) Waste of edible flesh generated because of inefficient handling, processing or distribution
iv) Simple, but technically unjustified loss of quality and value in the handling and sale of fishery products
According to the FAO, (Whittle and Hardy, 1992) future demands for fish will
come from developing countries, particularly Asia. Japan already uses under
utilized species (mackerel and sardine surimi) for its school lunch program (Dora
and Hiremath, 1991). By the year 2000, demand will surpass supplies from
conventional fish sources. Figure 3 lists a variety of traditional and surimi based
products (Sonu, 1986). Therefore, it seems logical economically to use under
utilized fish species as additional resources (Whittle and Hardy, 1992).
5
Chapter 1. Introduction
According to the above definition of under-utilized, farmed salmon may be
classified as under-utilized due to the loss of value incurred when salmon steak
sides are processed into canned salmon. Unfortunately, under-utilized species are
not always easy to process. Examples of processing difficulties include;
migratory patterns of species, seasonality of species, fluctuations in yield,
variability in composition, dark flesh, strong flavors, oxidation and rancidity in
frozen storage, and consumer prejudices (Whittle and Hardy, 1992). However,
there are some methods to overcome these hurdles. For instance, the following
approaches are useful in limiting lipid oxidation. Sodium bicarbonate removes fat
from high fat fish during washing. Super-decanters separate fish oil from meat.
Pressure showers mechanically remove dark muscle, skin and subcutaneous fat
(Putro, 1989). Examples of under-utilized species include; late run pacific chum
salmon, whiting, krill, hoki, hake, herring, and mackerel (Whittle and Hardy,
1992; Marris, 1991). As surimi production grows, so does the list of species used.
No longer are firm fleshed white fish the only raw material used for surimi.
Perhaps, fish protein technology and not the inherent fish characteristics will
eventually determine the usefulness of a species for surimi production (Holmes et
al., 1992).
1.5 The modern surimi process
Regardless of the species, modern production of surimi employs one of two
methods; onshore or offshore processing. Fresh fish makes the best quality
surimi. Therefore factory trawlers produce the highest quality surimi followed by
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Chapter 1. Introduction
factory mother ships and land based factories (Toyoda et al., 1992). Factory
trawlers process surimi within 24 hours post mortem.
1.5.1 Sorting and cleaning
Target species are separated from other species in the catch before fish are
processed. Typically, this step is manual. Next, fish are sorted by size to increase
final yield. The body temperature of fish should be kept just above the freezing
point, stored in crushed ice or in refrigerated sea water prior to processing
(Ohshima et al., 1993; Lee, 1986).
1.5.2 Filleting
Once sorted, fish are descaled or skinned and filleted. If skins remain on the fish,
they are descaled to prevent clogging of the deboning machine (Toyoda et al.,,
1992). It is important to process fish after rigor, otherwise extreme muscle
contractions result causing unacceptable textural qualities (Mackie, 1993).
Filleting involves heading, deboning, and evisceration. This may be manual or
automatic. Higher grade surimi results from proper viscera removal. Viscera
contains proteolytic enzymes and spoilage microorganisms that are detrimental to
surimi quality (Ohshima et al., 1993). Enroute to the separator via a conveyor
belt, fillets are spray washed to removed excess scales, viscera and manually
inspected for quality. Yield varies depending on season, presence and or absence
of roe and the original size of the fish (Lee, 1986). Figure 4 illustrates a flow
diagram of the surimi process and the processes' typical yield (Lee, 1985).
7
Chapter 1. Introduction
1.5.3 Separation of meat
A meat separator separates fish from bone and skin. Belt drums physically
remove unwanted fish parts while mincing the fish. The relatively soft fish flesh
is pressed through a screen to the belt drums' interior while the bone, skin and
viscera remain on the drums' exterior. The diameter of the screen affects output,
quality and the effectiveness of dewatering and leaching (Ohshima et al, 1993;
Toyoda et al., 1992). Medium size screen perforations are preferable because
they maintain decent yield and quality. Figure 5 depicts a typical design of a meat
separator (Lanier, 1992).
1.5.4 Leaching
After mincing, fresh water is used to leach the fish. Leaching removes
undesirable blood pigments, digestive enzymes, inorganic salts, sarcoplasmic
proteins, and trimethylamine oxides while concentrating the protein and
improving gel strength (Ohshima et al., 1993; Babbit, 1986; Lee, 1984). The
effectiveness of leaching is dependent on water-protein contact time, hardness of
the water, meatwater ratio, and effects of pH (Fig. 6, 7, 8, 9) (Ohshima et al.,
1993; Toyoda et al, 1992). Recent developments in the leaching process utilize
vacuums to accelerate lipid flotation and high-lipid content dark flesh removal
(Nishioka, 1984). Protein extraction appears to be maximized when agitated for
nine minutes (Toyoda et al., 1992). However, dewatering is more difficult when
protein residence time in water is extended. Therefore, protein residence time in
water should be kept to a minimum. Fifteen to twenty minutes for the entire
8
Chapter 1. Introduction
leaching process is industry standard (Toyoda et al., 1992). Wash water should be
near or below the temperature of the water normally inhabited by the fish to
maintain protein functionality and to prevent microbial proliferation (Hashimoto
et al., 1982). Generally, functional properties of protein decreases with increased
leaching temperatures. However, extraction of undesired sarcoplasmic proteins
increase with increased leaching temperatures. The first two washes use fresh
water, while the last wash contains 0.3% salt solution to facilitate dewatering
through osmotic pressure (Lee, 1986). Three washes o f a 3.T water to meat ratio
is considered appropriate. However, due to effluent concerns lower water: to
meat ratios have show to be effective and economical (T. L i n , 1997).
1.5.5 Intermediate dewatering
Intermediate dewatering takes place between each washing cycle to ease the final
dewatering cycle. About 8% of the starting mince is lost via dewatering screens.
However, centrifugation methods recover most mince (Toyoda et al., 1992).
Warm water facilitates water removal but may be deleterious to gel forming
abilities of the protein. High ionic strength water also facilitates dewatering.
L o w ionic strength wash water results in swollen high moisture fish. Therefore,
producers often add a small amount of salt in the final washing cycle. High salt
levels solubilize the protein and cause premature setting. Calcium and
magnesium in hard water are believed to cause color deterioration in frozen
surimi. Iron and manganese in hard water are believed to cause textural
deterioration in frozen surimi (Lee, 1986). Researchers believe calcium increases
9
Chapter 1. Introduction
crosslinking between myosin heavy chains leading to syneresis and the
development of hard rubbery surimi (Lee, 1986).
1.5.6 Refiner
Refiners separate the tissue, skin, and scales by using selective screen sizes from
partially leached and dewatered surimi prior to the final dewatering step. After
two washes, moderately wet meat (87-90%) is considered appropriate for refining
(Lee, 1986). Refiners typically consist of a cylindrical screen and a screw shaped
rotor. The washed mince is fed into the machine, and the soft meat is selectively
forced through the perforations under the compressive force generated by the
rotor. White, soft meat emerges from the front part of the refiner. Towards the
rear part of the refiner, the meat becomes increasingly harder and of poorer
quality. Only hard materials such as connective tissues, skin, bones, and scales,
which cannot pass through the perforations, are discharged through the end of the
refiner as reject. Strainers were the precursors to refiners. Strainers were used
after the final wash, and resulted in elevated temperatures due to lower moisture
contents. Lower moisture contents led to friction and subsequent protein
denaturation. Thus, refiners have alleviated this problem since tissue, skin, and
scales are separated when the minced fish flesh has a moderately wet meat
content, thus minimizing friction and subsequent premature protein denaturation
(Toyoda et al., 1992).
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Chapter 1. Introduction
1.5.7 Final dewatering and the importance of pH
A screw press completes the final dewatering step. The mince is pressed through
a screen to a desired moisture content (usually 74-84%). The isoelectric point of
fish protein is near a pH of 5.5 (Sonu, 1986). Normally the pH is just above the
isoelectric point to facilitate dewatering. Figure 10 illustrates the effect of wash
water temperature on the efficiency of dewatering (Toyoda et al., 1992). A low
pH will destabilize the protein and cause a reduction in the proteins' gelling
abilities. High pH values leads to dewatering difficulties due to the increase of
net negative charges on the proteins. Figure 9 illustrates dewatering difficulties
encountered at various mince and wash water pH (Sonu, 1986). Therefore, the
leach water maintains a pH of 7 to maximize water-holding capacity (Toyoda et
al., 1992; Lee, 1986).
1.5.8 Blending
Blending is the uniform incorporation of cryoprotectants into surimi to minimize
freeze denaturation of fish proteins during frozen storage (Lee, 1986). Generally,
cryoprotectants consist of 4% sucrose, 4-5% sorbitol and 0.2-0.3%
polyphosphates (Ohshima et al., 1993). Silent cutters and continuos blenders mix
cryoprotectants with dewatered surimi. A temperature increase often results from
increased mixing. Therefore, blending should be quick and efficient to prevent
loss of protein functionality (Lee, 1986). Chopping occurs at 15 second intervals
to avoid excessive temperature increases (Lee, 1986). Next, surimi is frozen
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Chapter 1. Introduction
quickly in a contact freezer prior to storage in a controlled freezer (Ohshima et al,
1993).
1.6 Cryoprotectants
Fish protein is especially susceptible to protein denaturation unless mixed
immediately with cryoprotectants before freezing. Without cryoprotectants,
myofibrillar proteins in surimi will denature and aggregate during extended frozen
storage. Numerous compounds have cryoprotective effects such as amino acids
and carboxylic acids. The surimi industry tends to use sucrose and or sorbitol at
the 8% level with 0.2-0.3% polyphosphates to prolong frozen storage
(MacDonald and Lanier, 1991; Ohshima et al., 1993). These cryoprotectants are
readily available and economical. There are several theories to explain the
cryoprotective effects of sugar. Cryoprotectants, particularly low molecular
weight sugars may preferentially hydrate protein and decrease the amount of
water removed from the protein. However, some sugars that are effective
cryoprotectants do not meet stearic hindrance requirements to allow such
preferential hydration (MacDonald and Lanier, 1991). This preferential hydration
involves sugar molecules that are small enough to bind to the surface of the
protein in effect, replacing water molecules on the surface of the protein. The
glass transition concept has been postulated to explain the cryoprotective nature
of high molecular weight carbohydrates. Glass is an amorphous solid that has a
liquid like structure. With a drop in temperature a solutions' viscosity will
increase and the molecular movement will decrease. Ice crystallization
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r 1. Introduction
practically ceases at the glass transition point. Proteins and other reactive
components trapped in a glass matrix are very stable. However, glass transition
behavior is less predictable in complicated protein systems (Ohshima et al., 1993).
The exact mechanism of cryoprotectants is unknown and more research is needed
to fully explain the action of cryoprotectants on fish proteins in frozen muscle
(Mackie, 1993).
Moisture also plays an important role in freeze thaw stability. The higher the
water activity, the more susceptible surimi is to freeze destabilization. One
approach to overcoming freeze thaw instability without reducing the water
activity is by using cryoprotective ingredients (Lee, 1986).
1.7 Solubilization
Saito et al. (1996) proposed a novel method called solubilization for prolonging
frozen storage of surimi. Solubilization dilutes surimi for frozen storage in an
attempt to minimize protein-protein and protein-fat interactions that may cause
protein denaturation. Solubilized samples consist of minced fish, cryoprotectants,
water, calcium chloride, and sodium chloride.
Cryoprotectants at the 8.30% level are added to the solubilized treatments to
retard protein denaturation. Water is added to the minced fish to physically
separate myofibrillar proteins.
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Chapter 1. Introduction
Calcium chloride is believed to form salt linkages between negatively charged
sites on two adjacent proteins. Through such a mechanism, calcium may
contribute to gel strengthening of surimi gels, but does not cause premature
gelation of surimi. Furthermore, the unique ability of surimi to gel at low
temperatures called the "setting" reaction is mainly due to the formation of
covalent bonds. These bonds form between neighboring amino acids of
glutamine and lysine in the presence of transglutaminase. The addition of
calcium to improve surimi gel strength may be due more to crosslinking of
transglutaminase than forming ionic linkages between proteins (Lanier, 1997).
Sodium chloride is required for proper gelation of surimi. Salt ions individually
hydrated with water bind oppositely charged groups exposed on the protein
surface. Intermolecular ion linkages among myofibrillar proteins are ruptured and
the proteins are dissolved in water because of their increased affinity for water.
Salt addition must undergo sufficient grinding to enhance protein solubilization
(Lanier, 1997). However, premature addition of salt will result in premature
setting of surimi. Therefore, it is likely that salt in solubilized treatments has a gel
strengthening effect rather than causing premature surimi gelation based on
results from other researchers (Saito et al., 1996).
Optimum levels of dilution, calcium chloride, and sodium chloride may exist for
a given surimi process and a given species based on the varying treatments results
obtained from Saito et al. (1996). Saito and coworkers solubilized surimi for
14
Chapter 1. Introduction
frozen storage and then reconstituted the surimi upon thawing into kamaboko
gels. They were able to produce a surimi gel that was better than the control.
1.8 Kamaboko making
Kamaboko is a traditional Japanese surimi-based product made from surimi. For
gelation, it is imperative that myofibrillar proteins are in the native state for the
first stage of kamaboko production (Mackie, 1993). Salt (usually 3%) chopped
into frozen surimi induces dissociation of the actomyosin, allowing a sol-gel to
form (Mackie, 1993). Functional additives such as whey protein and protease
inhibitors assist with maximizing kamaboko gel strength (Lee et al., 1992; Kim
and Park, 1997). Once blended, kamaboko is extruded into lubricated casings
and sealed. Next, kamaboko cooks for 20 minutes at 90°C in a water bath. Some
believe gelation of washed mince occurs from the heat-induced dissociation of the
actin-myosin complex followed by the formation of covalent linkages between
myosin chains (An et al., 1996; Saeki, 1996). The heat process varies in time and
temperature based on the species being used. After cooking, gels are immersed in
an ice bath, and then stored in a cold room for later evaluation of color, gel
strength, fold test, fat, moisture, protein, ash and SDS-PAGE electrophoresis.
1.9 Surimi quality
Surimi quality is often classified into 2 major categories: functional and
compositional. Compositional quality can be defined as chemical constituents
measured as mass or volume percentage of a unit quantity of surimi. The surimi
15
Chapter 1. Introduction
constituents of interest to food processors are protein, moisture, fat and visual
contaminants (Anon, 1991). Functional properties can be defined as the effects an
ingredient has on either the organoleptic properties of a food (flavor, odor,
texture, appearance) or the processing properties of a food, (resistance to tear or
breakage, etc). This definition implies functional properties are affected by the
quantity of ingredient added to the food and by the manufacturing process. All
measurements of functionality should be evaluated on a cooked product model, i.e
kamaboko (Anon, 1991). Gelling potential and color are the two most important
quality attributes of surimi (Saeki, 1996; Hsu et al, 1997). Standard methods for
measuring and specifying these properties of surimi have been proposed by the
surimi committee of the National Fisheries Institute (Anon, 1991) out of a need to
standardize industry practices.
1.10 Rheological properties of surimi gels
1.10.1 Effect of fish freshness, rigor condition, seasonality
There are several factors that affect the quality of surimi such as fish freshness,
size and seasonality. Generally freshness decreases with storage time.
Consequently, surimi produces its' maximum quality when it is processed shortly
after it is caught. The earliest fish can be processed is 5 hrs after catch, when the
fish has passed the rigor state. Fish in rigor state is difficult to process because it
is too stiff for machine handling. As a rule, fish maintains surimi-making quality
for 1-2 days after being caught (Lee, 1986). Fish caught during a feeding period
produce higher grade surimi (Lee, 1986).
16
Chapter 1. Introduction
1.10.2 Effect of chopping temperatures
Frozen surimi blocks are either broken into small pieces or partially thawed prior
to chopping. Research has shown that chopping surimi close to 0°C yields the
maximum quality of gels. Since chopping at 0°C is not always feasible, chopping
at 5°C still results in good gels (Kim and Park, 1997).
1.10.3 Effect of moisture content
Moisture content contributes to the economics of surimi and it contributes to
texture. Generally as moisture content (wet basis) increases from 75-85.5%, shear
' stress and strain decrease. A sample difference of 1% is acceptable for measuring
gel strengths using the puncture test. Figure 11 depicts the effect of moisture
content on gel strength and elasticity of high and low grade Pacific whiting and
Alaska pollock surimi. High grade surimi was prepared with sugar, sorbitol, and
sodium tripolyphosphate. In addition, high grade Whiting was prepared with
beeef plasma protein as an enzyme inhibitor. Low grade surimi was prepared by
thawing (48 hr at 25°C) and refreezing the high grade surimi (Reppond and
Babbit, 1997). Results from Yoon et al., (1997) indicate shear strain is
influenced less by moisture content than shear stress. Similarily, other
researchers have found water has a significant effect on shear stress but no effect
on shear strain of pollock surimi (Lanier et al., 1985; Hamann and MacDonald,
1992). Furthermore, at constant temperatures, shear stress values are proportional
to the concentration of crosslinked polymers and shear strain values are
proportional to the mean molecular weight of protein chains adjoining crosslinks
17
Chapter 1. Introduction
(Hamann and MacDonald, 1992). Hamann and MacDonald (1992) reported that
higher strain values were associated with lower free moisture in surimi gels
depending on species. These results are suppoerted by the trends depicted in
Figure 11 (Yoon et al., 1997).
1.10.4 Effect of functional additives
There are numerous effective and economic additives used by the surimi industry
to increase gel strength and elasticity. Least cost linear programming minimizes
ingredient cost (Hsu et al., 1997). However, not all quality relationships are linear
in nature. Figure 12 illustrates typical functional additives used in surimi
production (Park, 1994).
1.10.5 Effect of storage temperature
Time and temperature of surimi in frozen storage affects gel quality. Figure 13
illustrates the effect of cold storage temperature on the ashiness of Alaska pollock
surimi (Sonu, 1986). Ashiness of surimi made from fresh fish does not change
significantly when held below -20°C. However frozen temperatures above -10°C
causes the ashiness ability to gradually decrease and the surimi becomes useless
after 3 months. "Ashi" is defined as the combined effect of "springiness" and
"cohesiveness" and is evaluated by at least a 3 person panel of experts. A 10-
point grade system is used to evaluate the ashiness of 3 mm thick slices of
kamaboko. The 10-point grade system is as follows: 1 = crumbly, 2 = extremely
18
Chapter 1. Introduction
weak, 3 = very weak, 4 = weak, 5 = somewhat weak, 6 = average, 7 = somewhat
strong, 8 = strong, 9 = very strong, and 10 = eytremely strong (Sonu, 1986).
1.10.6 Effect of low temperature setting
Low temperature setting prior to cooking affects stress values. The optimum
setting temperature often corresponds to the water temperature of fishing grounds
that the fish are caught in (Kim and Park, 1997).
1.10.7 Effect of refrigerated storage on gels prior to evaluation
During 6 days of refrigerated storage, both shear stress and shear strain values
will increase. This is likely due to the increase of hydrogen bonding at lower
temperatures (Kim and Park, 1997). Figure 14 illustrates an increase in shear
strength and shear strain of Alaska pollock and Pacific whiting during 6 days of
refrigerated storage (Park, 1997). Therefore, for reproducibility, it is important to
measure gel strength at a constant time after forming kamaboko.
1.10.8 Effect of test temperatures
Gels exhibit maximum shear stress when tested at room temperature. On the
contrary, maximum shear strain values are observed at higher temperatures (50-
60°C) (Kim and Park, 1997; Howe et al., 1991). Figure 15 illustrates the effect of
test temperature on the shear strain and stress of Alaska pollock and Pacific
whiting kamaboko with various salt concentrations (Park, 1995).
19
Chapter 1. Introduction
1.11 Random Centroid Optimization
Random Centroid Optimization (RCO) is a technique that combines random
search and centroid search (Dou et al., 1993). Advantages of this optimization
method include; simplicity in theory, high search efficiency, no need for boundary
constraints resulting in a search stall, less chance of homing in on a local optima
rather than a global optimum, and the possibility of finding an unexpected
combination of conditions that may revolutionize conventional routines. RCO
also allows one to optimize a product of a poorly understood subject with a
minimum number of experiments. It is especially useful for optimizing non-linear
relationships with interactions between factors, such as many quality functions
(Dou et al., 1993; Nakai, 1990). Research done by Nakai et al, (1998) has
shown that RCO can be applied to find the global optimum of a multimodal
function.
1.12 Compositional aspects of surimi processing
1.12.1 Lipids in fish
Most lipids in fish are found in the head, liver, dark muscle and beneath the skin.
Therefore, if fish are properly gutted, skinned and cleaned most fat is removed.
However, there is some lipid in fish muscle known as phospholipid, which is
sensitive to oxidation. Phospholipid is contained in dark muscle fibers. Therefore
removal of dark muscle prior to leaching helps eliminate this unstable lipid
fraction. Phospholipids incorporated into refined fish proteins are especially
unstable in the presence of pro-oxidants (Mackie, 1993).
20
Chapter 1. Introduction
1.12.2 Proteins
Fish muscle proteins are grouped based on their solubility's in salt solution and
water. These groups are sarcoplasmic, myofibrillar, and connective tissue
proteins (Mackie, 1993).
1.12.2.a Sarcoplasmic proteins
Twenty to twenty five percent of total protein comes from proteins that are
soluble in water and dilute salt solutions (Haard et al, 1994). They include
myoglobin, enzymes and other albumins. These proteins may interfere with
myosin crosslinking during gel matrix formation because they do not form gels
and have low water holding capacities (Sikorski and Kodakowska, 1994).
Therefore, sarcoplasmic proteins are undesirable components in surimi.
Sarcoplasmic proteins such as hemoglobin and myoglobin are water soluble.
However, these proteins are easily oxidized by air such that the whole protein or
color imparting heme portion can attach to the water insoluble proteins and
survive the leaching process. This causes discoloration of the surimi and
introduces ferric iron which is a known catalyst of lipid oxidation (Lanier, 1997).
Therefore, the removal of color pigments is dependent on keeping the pigments in
their native state. Heme is very difficult to remove since their deposits are found
within the muscle (Greene, 1926). However, most myoglobin is found in dark
muscle. Therefore, physical removal of myoglobin is accomplished by separating
dark muscle from light muscle. Besides myoglobin and hemoglobin, there are
other soluble proteins in fish muscle that contribute to poor gelation. For
21
Chapter 1. Introduction
example, most fish possess heat stable proteolytic enzymes. These enzymes are
species dependent and are usually active in certain pH and temperature ranges
(Lanier, 1997).
1.12.2.b Myofibrillar proteins
Sixty to seventy-five percent of total protein are myofibrils. The major
constituents of myofibrils are actin, myosin, and tropomyosin (Mackie, 1993).
These proteins contribute to the unique gelling properties of surimi. Myosin
makes up the thick filament of myofibrils. It consists of 2 heavy chains coiled
around each other. At the end of myosin, a globular site associates with the
contractile mechanism between the thick and thin filaments. Attached to each
globular head are 2 light chains associated by non covalent bonds. Figure 16
depicts a schematic of actomyosin (Mackie, 1993). During frozen storage,
myosin undergoes aggregation resulting in toughening and loss of water holding
capacity. Generally, fish myosin is less stable than myosin of mammals or birds
(Sikorski, 1994). Addition of lower molecular weight sugars deters protein
denaturation during frozen storage (MacDonald and Lanier, 1991).
Myofibrillar proteins are highly reactive in their unfolded state. A gel results
when reactive protein ] surfaces form a 3 dimensional network entrapping water.
Figure 17 illustrates the 3 dimensional protein network formed during gelation of
surimi (Morrissey et al., 1995). There are 4 types of bonds that can link proteins.
Hydrogen bonds stabilize water within a gel particularly at colder temperatures
22
Chapter 1. Introduction
(Lanier, 1997). Calcium ions form positive salt linkages between negative sites of
two adjacent proteins. Salt ions act as a bridge between protein side groups and
water. Hydrophobic bonds form with exposed sites of denatured proteins. This
usually occurs at elevated temperatures. S-S linkages form with the oxidation of
two cysteine molecules on adjacent protein chains (Lanier, 1991).
Fifteen to thirty percent of the myofibrillar protein is actin. Actin is more stable
than myosin during frozen storage. Other myofibrillar proteins include
tropomyosin and troponins (Mackie, 1993; Sikorski, 1994).
1.12.2.C Connective tissue
Connective tissue accounts for 3-10% of total protein in fish. Upon cooking,
collagen breaks down to form gelatin. Since collagen lowers gel strength in
surimi, producers remove it during processing (Mackie, 1993).
1.13 Thesis hypothesis
This thesis was motivated by two needs: to determine if under-utilized salmon has
potential to make a high quality surimi gel and to determine if solubilization can
prolong frozen storage of salmon surimi. Rather than using pink salmon that has
a limited season and is locally unavailable fresh, farmed chinook salmon
(Onchorhynchus tshawytscha) was used for this experiment. Local industry
experts have identified the need to process leftover steak sides into a value added
product from farmed chinook salmon (Oncorhynchus tshawytscha), in order to
23
ter 1. Introduction
maximize profits (Agri-marine, 1996). These leftover steak sides may have
potential as a surimi based value added product.
Thesis hypothesis: Farmed chinook salmon can make better quality functional
kamaboko after solubilized frozen storage than surimi made from farmed chinook
salmon. Quality functional kamaboko will be evaluated on the basis of gel
strength, fold test scores, and SDS-PAGE electrophoresis gels.
\
24
Chapter 1. Introduction
Figure 1. Effect of the discovery of cryoprotectants and tighter catch controls on the Japanese fishing industry during 1965-1985 (Sonu, 1986)
25
Chapter 1. Introduction leaching
A) Traditional Surimi Production i m' filleting
stone-grinding with salt and ingredients
shaping of kamaboko steaming of kamaboko
Figure 2. Comparison of traditional and modern surimi production
2 6
Chapter 1. Introduction
S T E A M E D
• KAMABOKO
IMITATION CRAB MEAT, SHRIMP & SCALLOPS
HANPEN
NARUTO
R A W O R
F R O Z E N
SURIMI
GRINDING WITH
SALT AND
INGREDIENTS
I FRIED BROILED
B TEMPURA
H SATSUMA-AGE
CHIKUWA
OTHERS
I FISH
SAUSAGE
FISH HAM
Figure 3. Examples of surimi based products (Sonu, 1986)
27
Chapter 1. Introduction
WASTE
WASTE
1 0 0 -1
DEBONER 3 1.9 [—HIHCED
2 1.2 WASHING -WASHED REFINER
1 9.1 —REFINED DEHYDRATION
1 8.0 [—DEHYDRATED iY CRYOPROTECTANTS
I— SURIMI AFTER RECOVERY
19.5 2 3.8
Figure 4. Flow diagram of the surimi process and subsequent yield (Le< 1985)
28
Chapter 1. Introduction
AdjustableCrusherRoll
Ad jus tab leBel tTens ion Rol Headed & Gutted Fish
Perforated Drum \ / \ _ 11
s Extruded Fish Flesh ,C7
ced to Inside ofDrum<y
( : ? ^ H ^ U - C W ? v c ^ - S c r a p e r
Waste Chute
Adjustable Main Pressure Roll - i
Waste ,
Figure 5. Typical design of a surimi meat separator (Lanier, 1992)
29
Chapter 1. Introduction
10
Figure 6. Effect of agitation time on protein concentrations (g/1) with varying meat:water ratios (Toyoda et al., 1992)
30
Chapter 1. Introduction
T3
i-1
8 o U
87
85
83
o _ ** /
A o
VERY. SOFT. 1 1 1
| MEDIUM
S O F T J HARD. '
1 1 1 VERY HARD
1 I
600
400
200
4 6. 8 10 12
Hardness of Leaching Water
14 16
Q GO
s 0Q
b 3.
Figure 7. Effect of leach water hardness on gel strength and water content of croaker (Sonu, 1986)
3'1
Chapter 1. Introduction
J L L _ 1-
1 2 3 4 Washing Cycle
Figure 8. Effect of meat: water ratios and washing cycles on the removal of soluble proteins during leaching (Lee, 1986)
32
Chapter 1. Introduction
Figure 9. Effect of pH on the water holding capacity of minced meat (Sonu, 1986)
* The y-axis denotes the de watered volume of 3:1 water:meat mixture after it has been centrifuged, dewatered, expressed as % of initial volume
33
Chapter 1. Introduction
0 10 2 0 3 0
Time (min)
Figure 10. Effect of wash water temperature on the efficiency of dewatering (Toyoda et al., 1992)
34
Chapter 1. Introduction
Figure 11. Effect of moisture content on gel strength and elasticity of alaska pollock and pacific whiting (Yoon et al., 1997)
*high = high quality surimi (made under standard industry processing conditions)
low = low quality surimi (high quality surimi that is subjected to refreezing after 48 hrs.at25°C)
3 5
Chapter 1. Introduction
K i
W (D
00
00
60
50
40
30
20
10
0
• S h e a r Stress ESlShear Strain
Control BPP DEW FEW SPI WG WPC WPI 1% Dried Additive
3
2.5
- 2
- 1.5
1
: - 0.5
0.,
Figure 12. Effects of functional additives on kamaboko gel strength and elasticity (Park, 1994)
BPP = beef plasma protein, DEW = dried egg white, FEW = frozen egg white, SPI = soy protein isolate, W G = wheat gluten, WPC whey protein concentrate, WPI = whey protein isolate
36
Chapter 1. Introduction
8
CO w
•
60
I 3
' i 2
0
STORAGE TEMPERATURE
/ •© © . -35°C
0 1 2 3 4
Storage Duration (Months)
Figure 13. Effect of frozen storage temperature on gel strength (Sonu, 1986)
37
Chapter 1. Introduction
2 3 4 5.
Refrigerated Storage (Day)
Refrigerated Storage (Day)
Figure 14. Effect of refrigerated storage prior to gel strength and elasticity evaluations of alaska pollock and pacific whiting (Park, 1997)
38
Chapter 1. Introduction
60 ••0.5 -Ari -*-1.5 * 2 % N a C l
i i i i i i i i i r
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Temperature of Gels (°C) at Fracture
Figure 15. Effect of test temperature on gel strength of alaska pollock (Park, 1995)
3 9
Chapter 1. Introduction
Figure 16. Schematic of myosin (Mackie, 1993)
40
Chapter 1. Introduction
Myofibrillar proteins Protein interaction sites
Figure 17. Heat gelation of surimi (Morrissey et al., 1995)
41
Chapter 2. Materials and Methodology
Chapter 2
Materials and Methodology
2.1 Optimization of surimi treatments using random centroid optimization (RCO)
Three factors were entered into the random centroid optimization program;
calcium chloride, sodium chloride, and dilution. The ranges for each factor were
0.0-1.0 %, 0.0-3.0%, and 200-500% in total weight of solubilized samples,
respectively. The ranges entered for each of the factors came from previous RCO
work done by Saito et al., (1996). Once these ranges were entered into the RCO
program, the program randomly generated values for 9 treatments. Table 1 lists
the composition of the 9 treatments of solubilized surimi and the control surimi.
2.2 Surimi production
Due to processing limitations of the experimental plan, treatments were processed
in 2 batches. The first batch consisted of treatments 1, 2, 3 and the control. The
second batch consisted of treatments 4 through 9.
2.2.1 Fish source
In batch one, 87.76 kilograms of whole, gutted premium farmed chinook salmon
(Walcan Co., Vancouver) were transported by ferry to Campbell River and flown
by Canadian freight in 4 iced boxes to the Vancouver International Airport. Fish
arrived at the UBC Department of Food Science pilot plant for processing.
Salmon were approximately 10-15 hours post-mortem when received.
42
Chapter 2. Materials and Methodology
2.2.2 Filleting
Upon arrival, fish underwent a basic quality inspection. Fish appeared healthy
apart from a few eye lesions. Ice was removed and whole fish were weighed.
After weighing, fish were put on ice before filleting. Manual filleting commenced
in the pilot plant (25°C). Once filleted, and cut (approximately 5 X 5 cm pieces)
salmon was placed on half iced tubs in a 4°C cold room.
2.2.3 Grinding
Once filleted, grinding of fish commenced. Salmon pieces were fed through a
grinder (Beem Gigant, Germany) using a l/8th inch diameter extrusion
attachment. Ground fish were deposited into clean, dry tubs. The final weight of
minced fish was 36.30 kg.
2.2.4 Leaching
Fish were washed three times (batch style) in a large fish tote. The pH was
monitored through out the wash cycle to ensure a pH of 6-7. The pH was
measured by taking triplicate 50-mL samples of the minced fish in the wash water
with a pH meter (Corning, pH meter 220, Richmond Hill, Ont). Although not
used, one molar sodium bicarbonate solution was available for altering the pH, if
the minced fish pH fell below 6.
Wash 1
Minced fish (36.3 kg) was washed in 80L of precooled (4°C) tap water in a fish
43
Chapter 2. Materials and Methodology
tote. Temperatures were monitored (VWR thermometer, VWR Canlab, Edmonton
AB) through out the washings to ensure the wash water did not exceed 10°C. The
minced fish was mixed manually with a spoon at an approximate rate of 25
revolutions per minute for 5 minutes. Efforts to skim most of the fat off the
surface of the wash water were made before removing the washed fish. After
each wash cycle, consecutive 2L aliquots of minced fish were poured through
stainless steel sieves (1mm diameter) for initial dewatering. Once in the sieve,
minced fish was stirred constantly to remove excess water. Washed and partially
dewatered fish were stored in clean tubs until all of the fish was dewatered from
the fish tote. The final weight of minced fish was 46.25 kg.
Wash 2
Next, the fish tote was cleaned before adding the second wash water (4°C). Wash
two followed the same procedure as wash one. However, 46.25 kg of washed fish
was placed into 70L of tap water. The final weight of minced fish was 38.90 Kg.
Wash 3
Before the final wash, distilled water rinsed the fish tote. Next, 65L of 0.3% salt
in distilled water (4°C) was added to the fish tote. The fish was mixed manually
with a spoon for 5 minutes at an approximate rate of 25 revolutions per minute.
The solution stood for 10 minutes to solubilize the proteins. Sieves and
cheesecloth assisted in the dewatering of fish. Surimi was placed in a winepress
lined with cheesecloth (Grade 80, Vancouver Textiles Ltd., CA). Pressure (less
44
Chapter 2. Materials and Methodology
than 2 tons) was applied to dewater the minced fish using a hydraulic press. The
final weight of the fish after preliminary dewatering was 26.40 kg. The fish had a
high water content (based on experience from previous experiments) and
subsequently required centrifuging.
2.2.5 Dewatering
12-500 mL centrifuge containers held minced fish (Nalgene, Rochester NY) with
sealing caps in pre-cooled (4°C) GSA rotors (Dupont Sorvall, Missisauga, Ont).
Rotors were placed in Sorvall centrifuges (less than 10°C) (Sorvall RC 5B Plus,
Dupont Sorvall, Missisauga, Ont.) and centrifuged at 10,000 rpm. Supernatants
were discarded after each centrifugation until surimi reached a final moisture
content of 75% (w/v) and a weight of 20.65 kg.
2.3 Surimi solubilization
In batch one, minced fish was used to prepare treatments 1,2, 3 and the control.
Treatments 1, 2, and 3 were split into 5.25 kg aliquots for solubilization and the
control was split into 7-500 g aliquots. The solubilized treatments were made in a
4°C cold room. Distilled water dissolved pre-weighed sugars and salts in a
stainless steel bowl. Minced fish (5.25 kg), distilled water, dissolved sugars and
salts were combined to treatment weight. A balance determined final treatment
weights. A tabletop scale (Ishida, MTC-20, Japan) was tared and the distilled
water was added to the solubilized surimi until the appropriate weight was
reached for each treatment. Weights were calculated based on values given in
45
Chapter 2. Materials and Methodology
Table 1. For example, treatment one consisted of 5.25 kg of minced fish, 125g
CaCl2, 386g of NaCl,1.73 kg of cryoprotectants, and 7.49 kg of distilled water.
The final weight of treatment 1 (solubilized) = 3.97 X 5.25 kg = 20.84kg. Next,
treatments were put into 2L bags, sealed and frozen for about 5 hours in a -18°C
walk in freezer. This initial freezing took place because both -8°C freezers used
for the storage study (Refrigerator Incubator, Forma Scientific) had insufficient
power to freeze samples. Treatments were frozen in random order to
accommodate different chill rates within the freezer. When samples became
solid, they were assumed frozen and transported to the -8°C freezer for the storage
study. On days 3, 7, 14, 28, 56, and 84, treatments and controls were pulled from
storage and made into kamaboko. The -8°C freezer was chosen for the duration
of this study in order to speed up the progress of this experiment.
Batch two
The second batch of salmon was used to prepare treatments 4 through 9. The
methodology outlined in sections 2.21-2.3 of this thesis were followed for batch
one and batch two. However 136.2 kg of whole gutted premium chinook salmon
was received for the second batch. After filleting, and grinding there was 58.29
kg of minced fish. 116L and 102L of tap water were used for the first and second
washes, respectively. 94L of distilled water with 0.3% salt were used for the third
wash. After preliminary dewatering with the hydraulic press and final
centrifuging, 33.22 kg of surimi remained with a 75% moisture content for
kamaboko making. Four percent sucrose, 4% sorbitol, 0.15% tripolyphosphate
46
Chapter 2. Materials and Methodology
pentasodium, (Practical Grade Sigma) and 0.15% sodium pyrophosphate
(Mallinkrodt Chemical Works, St. Louis, MO) were mixed into the control using
a vacuum mixer (Stephan model UM-5, Columbus, Ohio). The solubilized
treatments in batch one and two used the same concentration of cryoprotectants
as the control. Batch one and two yielded 23.5% and 24.9% of the original whole
fish weight, respectively.
2.4 Kamaboko making
Treatments were removed from the freezer (-8°C) the day before kamaboko
making. Samples thawed overnight in a 4°C cold room. Treatments were pulled
from the cold room, diluted with varying amounts of chilled distilled water in 4L
plastic beakers and mixed (Nalgene, Rochester NY)(Fig. 23). This dilution step
was necessary to make water removal possible. Samples were initially dewatered
at room temperature. However, samples did not exceed 10°C. A pH Meter
(Model 620-Fischer Accumet, Nepean, Ont.) was used to measure triplicate
samples of diluted solubilized samples. Samples underwent preliminary
dewatering with grade #80 cheesecloth to minimize the volume of solubilized
surimi requiring centrifuging after pH determination.
Next, treatments were placed in 500 mL centrifuge containers (Nalgene,
Rochester, NY) and labeled. Containers were placed in GSA rotors (less than
10°C) (Dupont Sorvall, Missisauga Ont.). Treatments centrifuged multiple times
at a maximum speed of 10,000 rpm to a moisture content of 75% (wet basis).
47
Chapter 2. Materials and Methodology
Typically, 4-5 centrifugations were required. However, the number of
centrifugations required varied between treatments. The quick microwave method
(section 2.5.1.2) was used after each centrifugation to determine moisture content.
Centrifuged treatments were weighed and the amount of moisture needed to be
removed was calculated using the rapid microwave method. Likewise, if samples
were below the desired moisture content, the appropriate weight of distilled water
was added to the treatment based on the moisture content determined by the rapid
microwave method. Treatments were sealed in ziploc freezer bags, labeled and
placed in the cold room until all treatments were adjusted to the appropriate
moisture content.
A vacuum mixer (Stephan.model UM-5, Columbus, OH) was pre-cooled to 0°C
with a circulating ice bath made from saturated salt solution. Saturated salt
solutions were prepared by adding table salt to IL of water until salt precipitated
out of solution and then kept in the freezer at - 18°C overnight until used. Three
percent salt was added to each treatment to solubilize the mixture. Salt and
treatments were mixed at power one under vacuum (-50bar) for 5 minutes. When
the temperature exceeded 10°C due to blade friction, the mixer was stopped.
Mixing resumed at temperatures below 10°C. Immediately after mixing,
treatments were placed in a plastic bag, vacuum sealed (Model 30PI, Packaging
Aids Corp., San Francisco, CA) and placed in a cold room (4°C), until all
treatments were packaged.
48
Chapter 2. Materials and Methodology
The 5 lb. sausage stuffer (The Sausage Maker Inc., Buffalo, NY) was mounted on
plywood and fastened with "c" clamps to the tabletop in the cold room for
kamaboko extrusion. A hole was cut on each treatment bag and placed in the
stuffer with the opening facing the stuffer tube. The stuffer tube (2.2 cm
diameter) was sprayed with lubricant (Country Pure Vegetable Oil Cooking
Spray, Lucerne Foods Ltd.). One end of the casing was tied with a knot, the other
end with twine. Care was taken to extrude treatments with no air bubbles (Fig.
26). Occasionally, the stuffer tube was detached and a smaller secondary tube
assisted in pushing the surimi into the casing. This method of stuffing was only
1 used when an insufficient amount of surimi was obtained using the preferred
stuffing method. Treatments remained in the cold room (4°C) until all treatments
were stuffed. Each treatment had a constant diameter. Due to variation in
recovery for kamaboko making, sausages for each treatment varied in number and
length. This methodology produced sufficient kamaboko for both compositional
and functional analysis.
Treatments were then placed in a rectangular shaped plastic colander and cooked
at 90°C for 20 minutes. Kamaboko was then stored overnight in a 4°C cold room.
2.5 Compositional evaluation of kamaboko
2.5.1 Moisture determination (oven method)
Triplicate 2-5g (Sartorius AG, Germany) samples of treatments were dried at
100°C (Blue M Electric Co. Stabil Therm, Blue Island IL) to a constant weight in
49
• /
Chapter 2. Materials and Methodology
aluminum dishes. After 18 hours, samples were weighed again on an analytical
balance to determine moisture content. This method was adopted from the
manual of standard methods for measuring and specifying properties of surimi
(Anon, 1991). Samples were pre-dried for crude fat, protein and ash
determination using this method.
2.5.1.2 Moisture determination (microwave method)
A quick microwave (120V 60Hz microwave, Matsushita Electric Inc, Japan)
method determined moisture content during centrifugation. Triplicate 5 g
samples were dried to a constant weight on filter paper (Whatman #2) using 2
^ minute intervals at power 10. This method was adopted from a rapid drying
method (Bostian et al., 1985).
2.5.2 Crude fat determination
Triplicate pre-dried samples were sealed in plastic bags. Before fat extraction,
samples were ground in a Retch ultracentrifugal mill (model ZM 100, Glenn Mills
Inc., Clifton, NJ) and placed in ziploc bags. Ground (2-3g) samples were
(Sartorius AG, Germany) placed in tared cellulose extraction thimbles (22 X 80
mm, Whatman International Ltd., Maidstone England). Pre-dried milled samples
in thimbles were placed in a goldfish apparatus (Lab Con Co., Fisher Scientific
Inc., Nepean, Ont.) and petroleum ether extracted was used to extract the fat for 6
hours (Strugnell, 1989). The following equation determined % fat: % fat =
weight of crude fat/total weight of initial pre-dried sample (corrected for moisture
50
Chapter 2. Materials and Methodology
content). Crude fat was performed on all treatments on storage day 84, and for
each storage day for treatment 7.
2.5.3 Protein determination
Pre-dried samples (less than 1/3 gram) were ground using the Retch ultra-
centrifugal mill (model ZM 100, Glen Mills Inc., Clifton, NJ) and defatted using
the crude fat determination method. These samples were analyzed by the Dumas
method (Leco FP-428, Leco Corp. St. Joseph, MI) for nitrogen determination.
This method was adopted from the AOAC method (968.06) for protein (crude) in
animal feed. A factor of 6.25 was employed to estimate crude protein content.
Protein determination was performed in triplicate per treatment, for each storage
day.
2.5.4 Ash determination
Triplicate pre-dried samples (2 g) were weighed and placed in tared pre-dried
porcelain crucibles. Dry ashing was done with a muffle furnace at 550°C (Blue
M Box type muffle furnace, Blue Island, IL) for 24 hours. Percent ash was
defined as weight of ash/initial wet weight of sample. This method was adopted
from the AOAC method (900.02) for ash determination in meat (1990) (crude).
Dry ashing was performed on all treatments of storage day 84, and treatment 7.
2.6 Sample preparation
A miter box (35.6 X 13.0 X 7.6 cm- Mastercraft, Canada) helped to cut kamaboko
51
Chapter 2. Materials and Methodology
samples. Doctor blades (20 cm X 5 cm, razor sharp) fit perfectly into the miter
box guides and subsequently assisted with the cutting of kamaboko. Widths of 3
mm, 2.5 cm, and 5.0 cm were used to cut kamaboko samples for the fold test, gel
strength, and color tests, respectively.
2.7 Functional evaluation of kamaboko
2.7.1 Color
Samples were pulled from the cold room (4°C) the morning after they were
cooked and the casings were removed. Samples were allowed to reach room
temperature. Five samples were cut per treatment per storage time. Once all
treatments were cut, the Hunter II Labscan Calorimeter (Hunter Associates
Laboratory Inc., Reston, IL) was standardized for white and black tiles. Samples
were situated on top of a 1 cm diameter measuring port. "L", "a", "b" values were
recorded for each of the treatments with a computer. "L" denotes lightness on a 0
to 100 scale from black to white: positive "a" values mean red and positive "b"
values mean yellow. This method was adapted from a manual of standard
methods for measuring and specifying the properties of surimi (Anon, 1991).
2.7.2 Gel strength
Five samples were evaluated per treatment per storage time. Samples were
centered on a Texture Analyzer base (TA-TXT2 Texture Analyzer, Texture
Technologies Corp. Stable Micro Systems, Scarsdale, NY) and punctured with a
5-mm diameter probe at the rate of 1 mm per second (Fig. 28). Each graph
52
Chapter 2. Materials and Methodology
recorded the peak height (N) and the distance on the x axis to the peak (mm).
Peak height was defined as the highest point where the slope no longer continued
to form a straight line. This method was adapted from the manual of standard
methods for measuring surimi (Anon, 1991).
2.7.3 Fold test
Five samples were evaluated per treatment per storage time. Samples were taken
and folded up to two times with a forefinger and thumb based on the 6-point scale
for fold test. Table 2 lists the fold test scale used to evaluate gel elasticity
(Bouraaoui, 1995).
2.7.4 SDS-PAGE electrophoresis
Kamaboko gels (9 treatments and control) were added to Tris buffer (pH 8.0)
containing 5 mmol Tris, 8 M urea, 10% SDS w/v in a 1:10 volume ratio and
placed in centrifuge tubes (Safelock microcentrifuge tubes, Eppendorf, Westbury,
NY). Samples shook overnight in a shaker (Waterbath shaker, Eberach Co, Ann
Arbor, MI). Tubes were then centrifuged at 10, 000 rpm for 3 minutes (model
5415C, Eppendorf, Germany). Fifty ul of supernatant were transferred into
plastic centrifuge tubes. To each tube, 12.5 ul of SDS clear and 37.5 ul of 1 mmol
EDTA Tris buffer (pH 8.0) was added in a ratio of 1:3. In a fume hood, 3 ul of
B-mercaptoethanol, and 5 ul of bromophenyl blue indicator were pipetted into a
centrifuge tube. Tubes vortexed for one minute (Fischer Vortex, Genie 2, Fisher
Scientific). Tubes were boiled for 5 minutes in a rack to accelerate denaturation
53
Chapter 2 . Materials and Methodology
and cooled at room temperature. Samples centrifuged (Eppendorf 5415C,
Germany) for 3 minutes at 10, 000 rpm. Three microlitres of supernatant for each
treatment were delivered into wells and transferred onto SDS-PAGE gels (Phast
Gel Gradient 10-15, Pharmacia Biotech, Uppsala Sweden) using SDS buffer strips
and SDS sample applicators (Pharmacia Biotech, Uppsala Sweden). SDS gels
were run on the SDS Phast System (Pharmacia Biotech, Uppsala Sweden). Once
finished, gels were stained for 20 minutes with a 1:1 20% acetic acid and
Coomassie Brilliant Blue stock solution. Next, gels were de-stained twice with
30% methanol and 10% acetic acid. Gels were re-stored with 5% glycerol and
10% acetic acid. Wide range molecular weight standards determined molecular
weights (M.W. 6 500-205 000, Sigma, Aldrich Co., CA). The standards and there
molecular weights were: aprotinin, bovine lung (6, 500), a-lactalbumin, bovine
milk (14, 200), trypsin inhibitor, soybean (20, 000), trypsinogen, bovine pancreas
(24, 000), carbonic anhydrase, bovine erythrocytes (29, 000), glyceradldehyde-3-
phosphate dehydrogenase, rabbit muscle (36, 000), ovalbumin, chicken egg (45,
000), glutamic dehydrogenase, bovine liver (55, 000), albumin, bovine serum (66,
000), fructose-6- phosphate kinase, rabbit muscle (84, 000), phosphorylase b,
rabbit muscle (97, 000), galactosidase, E. coli (116, 000), myosin, rabbit muscle
(205, 000). This method was adopted by procedures followed in the Food
Science Departmernt at the University of British Columbia (Ogawa, 1997). SDS-"
PAGE electrophoresis was done on each treatment per storage time.
54
Chapter 2. Materials and Methodology
2.8 Statistical analysis
Excel spread sheets were used to conduct both one-way analysis of variance
between treatments and two-way analysis of variance for differences within a
treatment on a given day. Tukey's test determined what treatments or days were
significantly different. Multiple regression was conducted for RCO factors for
each treatment on a given storage day.
55
Chapter 2. Materials and Methodology
Table 1. Nine solubilized treaments and the control
Treatment Dilution (%) CaCI2 (%) NaCI (%)
1 397 0.60 1.85
2 421 0.28 2.6
3 271 0.35 2.56
4 202 0.30 0.49
5 487 0.44 0.70
6 452 0.48 0.86
7 258 0.05 0.38
8 240 0.29 1.82
9 372 0.31 2.70
control 0.00 0.00 0.00
56
Chapter 2. Materials and Methodology
Table 2. Fold test scale
F o l d t e s t s c o r e K a m a b o k o g e l a t t r i b u t e
1 B r e a k s b y f i n g e r p r e s s u r e
2 D o e s n o t b r e a k b y f i n g e r p r e s s u r e
3 C r a c k s i m m e d i a t e l y w h e n f o l d e d
4 C r a c k s g r a d u a l l y w h e n f o l d e d
5 N o c r a c k s s h o w i n g a f t e r f i r s t f o l d
6 N o c r a c k s s h o w i n g a f t e r s e c o n d f o l d
57
Chapter 3. Results and Discussion
Chapter 3
Results and Discussion
3.1 Compositional evaluation results of kamaboko
3.1.1 Crude protein content
Table three provides a summary of crude protein content (wet basis) in kamaboko
samples. Each treatment had a relatively low standard deviation for a given day,
indicating sample homogeneity. However, a substantial discrepancy between
protein values existed for treatments over time (13.59 ± 1.69%, n = 180). The
inconsistent crude protein concentration may have been due to inconsistent
sample preparation. Differences in sample density and consequently protein
concentration could have resulted from inconsistent sample extrusion (Reppond
and Babbit, 1997). Extrusion speed error and resistance error to the surimi
entering the casing likely contributed to variations observed in protein
concentrations. The variation in protein concentration was substantial when
compared to consistent values published by other researchers. For example,
Reppond et al., (1995) reported kamaboko protein concentrations of 17.7 ± 0.3%.
However, this value was for one sample at one storage time and commercial
surimi equipment produced the kamaboko. Other researchers have reported a
protein concentration mean of 11.25 ± 0.65% for surimi products. Therefore, the
crude protein average in this study appears appropriate, but the variation in
protein values does not.
58
Chapter 3. Results and Discussion
Other factors, such as the proportion of total fat, salts, sugars, and water in the
kamaboko samples could have affected crude protein content. Since there is no
trend corresponding to treatments with high non-protein content, it is reasonable
to suggest that the variation was due to poor sample preparation. Fortunately,
protein concentration within the ranges studied whether, high or low, seemed to
have little effect on overall gel quality. For example, treatments that had
relatively low protein concentrations also had high gel strengths and fold test
scores (control, day 28). Perhaps the various mean protein concentrations in this
study were not significant enough to show that increased protein concentrations
leads to higher gel strengths (Hamada, 1992; Hamann and MacDonald, 1992).
3.1.2 Moisture content
The mean moisture content of kamaboko gels were 74.5 ± 5.5% (n =180) after
cooking. Table 4 presents a summary of the moisture contents (wet basis) in
kamaboko gels. These values are consistent with prominent surimi manufacturers
company values. Anon (1993), reported a final screw press and kamaboko
moisture content of 82-84% and 74-75.5% in Alaska pollock, respectively. The
high moisture content is economical from industry's perspective since water is
cheaper than protein. However, as moisture increases, gel strength decreases
(Lanier, 1992)? Reppond et al., (1993) recognized the difficulty in producing
surimi with the same moisture content. Subsequently, a correction factor was
developed to compensate for surimi with different moisture contents.
Unfortunately, this factor is only suitable for surimi evaluated for shear stress and
59
Chapter 3. Results and Discussion
strain (not punch force). Due to the lack of uniformity of samples using a punch
test, mathematical models cannot predict gel quality based on various moisture
contents. This is not surprising, since other researchers (Hamann and
MacDonald, 1992) have found the torsion test to be far more reliable than the
punch test due to the geometry of samples. The torsion test is preferable to the
punch test for several reasons. The torsion test does not cause the gel to undergo
major geometric changes so that shear stress and strain may be calculated. On the
contraty, gross shape changes occurs during the punch test and stress and strain
cannot be easily determined quantitatively. Hamann and MacDonald (1992)
provide a detailed explanation on how to prepare surimi gels for the torsion test.
Due to equipment limitations, the punch test was used instead of the torsion test in
this thesis. Reppond et al., (1997) suggested a 1% moisture level difference was
comparable without mathematical or physical adjustments. Therefore, it was not
reasonable to compare treatments in this experiment due to the range in moisture
values. However, it was appropriate to make a few general conclusions. For
example, the control had the lowest average moisture content, and yet it did not
have the highest average gel strength. This indicates that some of the solubilized
treatments were clearly better than the control since both their gel strengths and
moisture contents were significantly higher than the control (i.e. treatment 7).
Results from one-way ANOVA and Tukey's test support this conclusion.
Surimi samples were stuffed into casing with mean moisture contents of 77 ±
2% (n =180) but lost an average of 2.5% moisture during the cooking process.
60
Chapter 3. Results and Discussion
Cavestany et al., (1994) also found a 2% expressible moisture loss of kamaboko
gels after cooking. The casings were not waterproof since casings had knots at
both ends.
3.1.3 Crude fat content
Crude fat content was analyzed for all samples on day 84 and for the best
treatment (treatment 7). Day 84 was chosen for fat analysis for two reasons.
Firstly, day 84 was the last storage day in this study, and subsequently crude fat
content values should represent the poorest quality kamaboko due to protein
degradation over the storage study. Secondly, day 84 crude fat content analysis
indicated fat values between treatments. Treatment 7 was chosen for crude fat
analysis, since it produced the best quality kamaboko gel. Furthermore, treatment
7 crude fat values might have indicated whether or not sample homogeneity
between storage days for a given treatment existed. The crude fat content of
kamaboko gels for storage day 84, and the best treatment (7) was 4.4 ± 2.4%.
Table 5 lists mean and standard deviations of crude fat contents in kamaboko gels.
Reppond et al., (1993) reported a fat content of 0.9 ± 0.0% for herring surimi.
However, they suggested this value was likely unrealistically low due to low belt
pressure used during mechanical deboning. Since herring is a fatty fish (James,
1988), one might expect similar fat values for farmed chinook salmon kamaboko.
Unfortunately, there are no values in the literature specifically cited for kamaboko
made from farmed chinook salmon to make an appropriate comparison. Industry
typically uses low fat fish such as pollock for surimi production (Anon, 1993).
61
Chapter 3. Results and Discussion
The high fat values in this experiment are likely due to the batch process used to
wash the minced fish, the initial fat content of the salmon, and the omission of the
"refiner step". A fat layer on the wash water surface contaminated the minced
fish as it was removed from the fish tote, even though researchers tried to remove
the fat prior to collecting the washed minced fish. A continuous washing system
(commercial surimi equipment) would have been a much more effective way to
remove the fat from the minced fish. The advantages of low fat kamaboko are
numerous. For example, samples will have a better shelf life and quality.
According to Kennish et al., (1990) farmed chinook salmon {Oncorhynchus
tshawytscha) generally have a muscle crude fat content of 2.6-4.0%. However,
variation is greatly dependent on the diet, and the genetic make up of the salmon.
Others have reported higher crude fat content values of salmon in the range of 1.6
-18% (Greene, 1926). The fanned chinook salmon used for this experiment had a
muscle crude fat content of 17 ± 1% for batch one and 5.5 ± 0.5% for batch two
(n=3). The variation in fat content between batch one and batch two is likely due
to sampling procedures, not seasonality of the fish. Industry experts reported that
west coast salmon fish farms have a consistent crude fat content during the time
period that farmed fish was obtained for this experiment (Mitchell, 1998).
Regardless of the crude fat content of the salmon fillets, kamaboko treatments had
similar crude fat contents.
3.1.4 Ash content
Ash content was performed on all fillets, day 84 treatments, and treatment 7 for
62
Chapter 3. Results and Discussion
each of the storage days. Table 5 lists crude ash content means and standard
deviations of kamaboko gels on day 84. Table 6 lists average ash and fat
contents of treatment 7. Solubilized treatments with higher salt concentrations
generally had higher ash contents (i.e. treatments 2, 3, and 8). Similarly, the
control with only 3% sodium chloride added, had relatively low ash
concentrations. Furthermore, the fillets had substantially lower ash values than all
treatments or the control. These results suggest that treatment salts bound to the
protein matrix of the kamaboko gels. Discrepancies between final kamaboko ash
content and initial salt added to treatments is possibly due to centrifuging
treatments after solubilization. Salts were lost in the supernatant after repetitive
centrifuging. Furthermore, attempts to adjust the treatments to a consistent pH
were unsuccessful during solubilization. Such an effort likely added error to this
experiment and influenced final ash content in kamaboko samples. More
importantly, these results provide a partial explanation for the significant
treatment effect observed with multiple regression of gel strengths versus
treatment factors.
3.1.5 pH
The pH greatly affects the dewatering ability of minced fish. The minimum
water holding capacity (WHC) of minced meat occurs at the isoelectric point (pH
5.3) of myofibrillar proteins. At the isoelectric point, the net charge on the
protein is zero and there is a maximum number of interprotein ionic linkages. As
a consequence, the protein matrix shrinks and the WHC is at a minimum. It is not
63
Chapter 3. Results and Discussion
recommended to dewater minced meat near the isoelectric point since gel forming
abilities decline sharply at pH values less than 6 (Sonu, 1986). Furthermore,
actomyosin exhibits it's highest resistance to freeze denaturation at pH values
slightly higher than 7.0. Therefore, it is advisable to process minced meat at pH
values between 6.2-7.0 (Noguchi, 1982). pH values greater or less than the
isoelectric point causes minced meat to swell. Dominate positive or negative
charges at acidic, and basic pH's respectively repel protein molecules and explain
the pH-WHC relationship (Anon, 1993). Table 7 lists the average pH values for
the solubilized treatments and control over the storage study. Figure 9 depicts a
typical diagram of the effects on pH on the swelling of minced meat.
3.2 Functional evaluation results of kamaboko
3.2.1 Color
Hunter "L", "a", "b" values were collected on kamaboko gels for all treatments
and days. Table 8 lists Hunter values for each treatment over time and Table 9
lists the standard deviation values associated with Table 8. Hunter values were
very consistent between treatments and over time. The only trend that is
somewhat apparent is that the treatments became increasingly lighter over the
storage time (higher "L" values). Treatments with low levels of added salts
appeared to be the least color stable (control, treatments 6 and 7), while
treatments with high levels of added salts were color stable (Treatments 1, 2, 3).
This is only mentioned for interest, since it is beyond the scope of this thesis to
explain this phenomenon. Another explanation for lighter color values may be
64
Chapter 3. Results and Discussion
the higher moisture kamaboko samples. However, the spread in moisture content
does not relate well to color trends in treatments.
3.2.2. Gel strength
Gel strength is frequently cited as the most important factor for evaluating
kamaboko gels (Lee, 1992). Usually over time, gel strength decreases due to
protein degradation. Table 10 reports the means and standard deviations for gel
strengths (N x mm) for all kamaboko gels. Higher temperatures accelerate
protein degradation and gels stored at -8°C are usually rendered useless after 3
months (Lee, 1992). Two-way A N O V A was conducted for storage time and
treatment effects. Since two-way A N O V A was significant, one-way A N O V A
was conducted to compare treatment effects and storage effects. Surprisingly,
one-way A N O V A indicated that gel strength did not change over time (p < 0.05).
Typically, researchers have observed a downward trend in gel strength over time
(Tamoto, 1971; Noguchi, 1970). The insignificance of the time effect may be
truly significant. This can happen when significant differences are canceled due
to variations in treatment trends. For example, an upward trend for gel strength
over time could be canceled out by a downward trend for gel strength resulting in
similar means and therefore no significant difference (Kozak, T., 1998).
Coincidentally, both upward and downward trends were obtained when treatment
gel strengths were plotted over time.
Since there was a significant difference in treatments, multiple regression was
65
Chapter 3. Results and Discussion
performed on each treatment. The impact of treatment factors (sodium chloride,
calcium chloride and dilution) on gel strengths was examined for each treatment.
Table 11 lists Revalues and the factors that contributed to treatment effects.
Since differences in treatments were not consistent over the storage study, it
would be presumptuous to provide a prediction equation for the R2-values.
Therefore, it may only be appropriate to suggest that factors did have a significant
impact on the gel strength quality (Kozak, T.,1998). Furthermore, when the
control was added to the list of treatments for multiple regression, no significant
regression statistics were obtained. Therefore, the control was omitted from the
multiple regression. This action was considered justifiable since lower factor
concentrations contributed to higher gel strengths. Calcium chloride and sodium
chloride appeared to have more of an impact on gel strength than the dilution
factor. Nevertheless, dilution was significant on certain storage days.
3.2.3 Fold test scores
Table 12 summarizes fold test scores for all kamaboko gels. Two-way ANOVA
was conducted on storage time and treatment effects. Since significant
interactions were observed (p < 0.05), one-way ANOVA was conducted on
storage time and treatment effects. Similar to gel strength (N x mm), fold test
scores were significant between treatments but not over time. Treatments were
compared with Tukey's test (Table 12).
66
Chapter 3. Results and Discussion
3.2.4 SDS-PAGE Electrophoresis
SDS-PAGE Phast gels were run for each kamaboko treatment for each storage
day. SDS-PAGE results support results from the gel strength and fold test scores
(Fig. 29). For example, treatment 7 (the best treatment) showed little or no
degradation of the myosin heavy chain at day 84 of the storage study.
Degradation of the myosin heavy chain indicates protein degradation
(Yongsawatdigul et al., 1997). Surprisingly, day 3 of treatment 7 also showed .
little or no protein degradation. One would expect some degradation due to the
low gel strength of treatment 7 on day 3. Day 3 of treatment 7 may be an
anomaly since similar trends were not observed with other treatments at day 3 of
the storage study. See Fig. 29 for a comparison of protein degradation seen in the
control, treatment 7 (best), treatment 6 (worst) over the storage study.
67
Chapter 3. Results and Discussion
T a b l e 3. C r u d e prote in fract ion in k a m a b o k o gel (wet basis , n = 3)
Treatments Day 3 Day 7 Day 14 Day 28 Day 56 Day 84 Total Av. Protein (cv.)
Protein (cv.)
Protein (cv.)
Protein (cv. ) '
Protein (cv.)
Protein (cv.)
Protein (cv., n=18)
1 0.13 (0.00)
0.15 (0.01)
0.14 (0.00)
0.12 (0.01)
0.12 (0.00)
0.12 (0.00)
0.13abc* (0.01)
2 0.11 (0.00)
0.12 (0.00)
0.13 (0.00)
0.12 (0.01)
0.12 (0.01)
0.12 (0.01)
0.12ab
(0.01)
3 0.14 (0.00)
0.14. (0.00)
0.11 (0.00)
0.13 (0.00)
0.12 (0.01)
0.11 (0.00)
0.12ab
(0.01)
4 0.17 (0.00)
0.16 (0.00)
0.15 (0.00)
0.13 (0.00)
0.16 (0.02)
0.14 (0.00)
0.15d
(0.01)
5 0.16 (0.00)
0.16 (0.00)
0.14 (0.00)
0.13 (0.00)
0.12 (0.00)
0.14 (0.01)
0.14°" (0.02)
6 0.15 (0.00)
0.15 (0.00)
0.13 (0.00)
0.14 (0.00)
. 0.12 (0.01)
0.17 (0.01)
0.14bc
(0.01)
7 0.11 (0.00)
0.15 (0.00)
0.12 (0.00)
0.16 (0.00)
0.12 (0.00)
0.16 (0.01)
0.14^ (0.02)
8 0.13 (0.00)
0.12 (0.00)
0.13 (0.00)
0.14 (0.00)
0.11 (0.00)
0.14 (0.00)
0.13a b c
(0.01)
9 0.13 (0.00)
0.15 (0.00)
0.15 (0.00)
0.15 (0.00)
0.12 (0.01)
0.16 (0.00)
0.14* (0.01)
Control 0.14 (0.00)
0.15 (0.00)
0.11 (0.00)
0.10 (0.00)
0.14 (0.00)
0.10 (0.00)
0.12ab
(0.02)
Total Av. Protein
(c.v.,n=30)
0.14a* . (0.02)
0.14a
(0.01) 0.13a
(0.01) 0.13a
(0.02) 0.13' (0.02)
0.13a
(0.02)
*values in a column (treatments) or in a row (days) with the same superscript are not significantly different (p < 0.05)
68
Chapter 3. Results and Discussion
T a b l e 4. M o i s t u r e fract ion in k a m a b o k o gels (wet basis, n = 3)
Day 3 Day 7 Day 14 Day 28 Day 56 Day 84 Total Av. Treatments Moisture
(c.v) Moisture
(cv) Moisture
(cv) Moisture
(cv) Moisture
(c.v) Moisture
(c.v) Moisture
(c.v., n=18)
1 0.76 (0.00)
0.73 (0.00)
0.72 (0.00)
0.73 (0.02)
0.72 (0.00)
0.73 (0.00)
0.73"°* (0.02)
2 0.79 (0.00)
0.76 (0.00)
0.72 (0.00)
0.72 (0.00).
0.73 (0.00)
0.73 (0.00)
0.74bc
(0.06)
3 0.75 (0.23)
0.74 (0.00)
0.80 (0.09)
0.72 (0.01)
0.69 (0.00)
0.73 (0.00)
0.75*° (0.06)
4 0.72 (0.00)
0.71 (0.00).
0.73 (0.00)
0.72 (0.00)
0.75 (0.00)
0.71 (0.00)
0.71ab
(0.02)
5 0.72 (0.00)
0.72 (0.00)
0.72 (0.00)
"0.71 (0.00)
0.73 (0.00)
0.71 (0.00)
0.72b
(0.02)
6 0.72 (0.00)
0.74 (0.00)
0.74 (0.00)
0.73 (0.00)
0.75 (0.00)
0.71 (0.00)
0.72b
(0.02)
7 0.77 (0.00)
0.75 (0.00)
0.74 (0.00)
0.76 . (0.00)
0.75 (0.00)
0.75 (0.00)
0.75° (0.02)
8 0.79 (0.00) '
0.75 (0.02)
0.75 (0.00)
0.73 (0.00)
0.73 (0.00)
0.73 (0.00)
0.75c
(0.02)
9 0.76 (0.00)
0.63 (0.00)
0.73 (0.00)
0.73 (0.00)
0.73 (0.00)
0.73 (0.00)
0.74bc
(0.02)
Control 0.65 (0.00)
0.63 (0.00)
0.71 (0.00)
0.71 (0.00)
0.71 (0.00)
0.71 (0.00)
0.69a
(0.05)
Total Av. Moisture
(c.v., n=30)
0.74a" (0.07)
0.72a
(0.05) 0.73a
(0.05) 0.72a
(0.02) 0.73a
(0.02) 0.72a
(0.02) 0.72a
(0.02)
* values in a row (days) or in a column (treatments) with different superscripts are significantly different (p < 0.05)
69
Chapter 3. Results and Discussion
Table 5. Fat and ash fractions in day 84 kamaboko gels (wet basis, n
Treatments Day 84 Day 84 Ash Fat (c.v) (cv)
1 0.088bc* 0.042 a b c
(0.00) (0.01)
2 0.085b c ' 0.045 a b c
(0.00) (0.01)
3 0.084b c 0.040 a b c
(0.01) (0.00)
4 0.076b c 0.065b c
(0.00) (0.00) .
'5 0.072b c 0.034 a b
(0.00) (0.00)
6 0.087c 0.068 c
(0.00) (0.00)
7 0.053b 0.021a
(0.02) (0.00)
8 0.082bc 0.045 a b c
(0.00) (0.00)
9 0.0483 0.034a b
(0.00) (0.02)
Control 0.025a 0.038 a b c
(0.00) (0.02)
*values in a column (treatments) with different superscripts are significantly different (p < 0.05)
70
Chapter 3. Results and Discussion
Table 6. Fat and ash fractions in treatment 7 kamaboko gels (wet basis, n = 3)
Treatment 7 Treatment 7 Days Ash Fat
(cv) (cv)
3 0.13C* 0.02 a
(0.00) (0.00)
7 0.09 b 0.03 b
(0.02) (0.01)
14 0.10 b 0.04 b
(0.00) (0.01)
28 0.10 b .03 b
(0.00) (0.00)
56 0.09 b 0.03 b
(0.00) (0.02)
84 0.05 a 0.02 a
(0.02) (0.00)
*values in a column (days) with the same superscripts are not significantly different (p< 0.05)
71
Chapter 3. Results and Discussion
Table 7. PH values of solubilized kamaboko throughout the storage study (n = 18, (3 X 6 storage days))
Treatments PH Std. dev
1 7.31 0.22
2 6.59 0.09
3 7.09 0.23
4 7.04 0.25
5 6.72 0.15
6 6.36 0.14
7 6.80 0.11
8 8.34 0.27
9 6.87 0.13
72
Chapter 3. Results and Discussion
Table 8. Mean Hunter "L", "a", "b" values of kamaboko gels (n=5)
T r e a t m e n t s D a y 1 2 3 4 5 6 7 8 9 C o n t r o l
II n I II II ^ I I II n ^ I I II ^ I I II l^ii II
3 6 7 . 3 7 1 . 0 6 6 . 5 6 8 . 4 6 8 . 4 7 0 . 6 6 9 . 9 7 3 . 0 6 9 . 2 6 9 . 2 7 6 8 . 3 7 3 . 0 7 0 . 0 6 9 . 5 7 2 . 4 6 8 . 7 71 .1 7 0 . 5 6 8 . 8 7 0 . 5
1 4 6 8 . 8 7 1 . 7 6 9 . 4 6 9 . 9 7 1 . 5 7 3 . 3 7 2 . 9 6 9 . 5 6 8 . 7 7 4 . 7 2 8 6 8 . 8 7 0 . 2 6 8 . 3 7 0 . 4 7 2 . 0 7 3 . 0 7 4 . 9 7 0 . 2 7 1 . 8 7 4 . 6 5 6 6 9 . 3 7 1 . 5 7 0 . 6 7 0 . 6 7 4 . 6 7 3 . 8 7 5 . 2 7 0 . 6 7 0 . 9 7 6 . 8 8 4 6 9 . 1 7 1 . 9 7 0 . 6 7 2 . 0 71 .1 7 4 . 5 7 6 . 6 71 .1 7 1 . 2 7 7 . 4
3 1 7 . 5 1 7 . 5 1 8 . 5 1 7 . 4 7 1 8 . 2 1 5 . 7 1 6 . 6 1 6 . 6
1 4 17.1 1 5 . 0 17.1 1 6 . 2 2 8 1 6 . 9 1 4 . 9 1 6 . 5 1 6 . 0 5 6 1 6 . 3 1 4 . 6 1 5 . 2 1 5 . 7 8 4 1 5 . 2 1 4 . 5 1 5 . 3 1 4 . 0
" a " " a " " a " " a " " a " " a " 1 6 . 3 1 6 . 4 1 7 . 0 1 3 . 3 1 8 . 3 17.1 1 5 . 8 1 6 . 8 1 4 . 0 1 7 . 4 1 6 . 6 1 6 . 1 1 5 . 6 1 4 . 5 1 2 . 9 1 7 . 3 16.1 1 3 . 6 1 4 . 5 1 4 . 0 1 1 . 3 1 6 . 8 15.1 1 2 . 9 1 2 . 9 1 3 . 0 1 0 . 5 1 6 . 1 1 4 . 7 12.1 1 5 . 6 13.1 9 . 5 1 6 . 2 1 4 . 5 1 0 . 5
"b" "b" "b" "b" "b" "b" "b" " b " "b" "b" 3 1 4 . 5 1 4 . 9 1 5 . 2 1 5 . 9 1 5 . 0 1 5 . 3 1 4 . 7 1 3 . 4 1 4 . 9 1 5 . 5 7 1 4 . 7 1 4 . 0 1 4 . 5 1 5 . 2 1 5 . 3 1 5 . 0 1 3 . 9 1 5 . 2 1 5 . 1 1 5 . 2
1 4 15.1 1 4 . 8 1 5 . 5 14.1 1 4 . 6 1 3 . 8 1 3 . 3 1 4 . 6 1 4 . 3 1 3 . 9 2 8 1 4 . 9 1 4 . 6 1 4 . 6 1 4 . 3 1 4 . 7 1 3 . 9 1 2 . 6 1 4 . 8 1 4 . 0 1 3 . 8 5 6 1 4 . 4 1 4 . 2 1 4 . 4 1 4 . 6 1 3 . 6 1 3 . 5 1 2 . 8 1 4 . 9 1 4 . 4 1 3 . 3 8 4 1 4 . 8 1 4 . 6 1 4 . 6 1 4 . 5 1 4 . 2 14.1 1 2 . 4 1 4 . 7 1 4 . 7 1 3 . 4
73
Chapter 3. Results and Discussion
Table 9. Standard deviations of Hunter " L " , "a", "b" values of kamaboko gels (n=5)
Treatments Day 1 2 3 4 5 6 7 8 9 Control
" L . " l l ^ l l
" L " •f | it l l ^ l l II | II
r 11 vi " L "
3 0.42 0.20 0.25 0.56 1.20 0.53 0.26 0.55 0.31 0.67
7 0.27 0.91 1.33 0.89 1.81 0.77 0.88 0.45 0.45 1.47
14 0.24 0.22 0.23 0.28 0.16 0.49 0.15 0.17 0.26 0.28
28 0.22 0.40 0.40 0.37 0.23 0.12 0.22 0.17 0.35 0.22
56 0.38 0.39 0.30 0.17 0.34 0.28 0.11 0.17 0.44 0.35
84 0.54 0.19 1.35 0.51 0.27 0.13 0.23 0.34 0.39 0.19
"a" "a" "a" "a" "a" "a" "a" "a" "a" "a"
3 0.42 0.20 0.25 0.56 1.20 0.53 0.26 0.55 0.31 0.67
7 0.18 0.28 0.11 0.12 0.10 0.11 0.28 0.17 0.14 0.13
14 0.07 0.27 0.14 0.15 0.18 0.09 0.26 0.20 0.30 0.10
28 0.40 0.19 0.29 0.08 0.17 0.20 0.13 0.15 0.28 0.09
56 0.29 0.15 0.31 0.13 0.22 0.16 0.14 0.44 0.14 0.33
84 0.54 0.19 1.35 0.51 0.27 0.13 0.23 0.34 0.39 0.19
"b" "b" "b" "b" "b" "b" "b" "b" "b" "b"
3 0.19 0.09 0.08 0.48 0.31 0.37 0.12 0.17 0.20 0.33
7 0.17 0.23 0.10 0.34 0.09 0.36 0.28 0.17 0.22 0.10
14 0.27 0.21 0.13 0.15 0.10 0.13 0.19 0.21 0.06 0.14
28 0.20 0.19 0.13 0.03 0.09 0.14 0.13 0.21 0.19 0.13
56 0.16 0.12 0.24 0.12 0.15 0.12 0.07 0.12 0.16 0.12
84 0.12 0.16 0.17 0.26 0.23 0.07 0.23 0.09 0.14 0.26
74
Chapter 3. Results and Discussion
Table 10. Gel strengths (N x mm) of kamaboko gels (n =5)
Day 3 Day 7 Day 14 Day 28 Day 56 Day 84 Total Av. Treatments Gel
strength (std. dev)
Gel strength
(std. dev)
Gel strength
(std. dev)
Gel strength
(std; dev)
Gel strength
(std. dev)
Gel strength
(std. dev)
Gel strength (std. dev)
(n=30)
1 26.28 (3.30)
10.15 (1.27)
5.80 (1.49)
5.38 (1.06)
6.35 (1.14)
6.17 (1.03)
10.02 b c* (7.73)
2 13.02 (2.99)
7.88 (0.63)
4.72 (1.18)
3.63 (0.64)
5.00 (1.33)
6.17 (1.03)
6.29 a b
(3.68)
3 17.59 (3.94)
8.64 2.53)
4.28 (1.27)
7.68 (0.64)
5.72 (1.34)
5.93 (1.63)
8 .31 a b c
(4.88)
4 4.91 (0.83)
3.81 (0.90)
14.69 (2.88)
11.20 (2.41)
8.06 (2.43)
5.51 . (1.08)
8 .02 a b c
(4.28)
5 10.80 (1.73)
4.05 (0.42)
4.88 (1.07)
3.50 (0.76)
7.69 (1.98)
7.07 (1.33)
6 .33 a b
(2.82)
6 3.35 (0.40)
10.05 (1.18)
6.80 (0.84)
3.88 (0.36)
5.23 (1.50)
2.54 (0.65)
5.31 a
(2.70)
7 3.77 (0.61)
12.91 (3.10)
11.75 (3.10)
10.82 (2.57)
12.53 (1.55)
12.63 (2.66)
10.74° (3.93)
8 6.86 (2.14)
9.63 (3.60)
4.91 (2.14)
6.29 (1.62)
6.58 (1.61)
6.10 (2.21)
6 .73 a b c
(2.56)
9 . 34.92 (10.16)
20.14 (4.45)
11.71 (2.94)
15.97 (3.15)
8.74 (1.50)
.84 (0.36)
15.72 d
(11.25)
Control 9.2 (1.58)
7.37 (0.72)
6.57 (1.07)
8.79 (2.33)
6.65 (0.62)
7.23 (1.92)
7.64 a b° (1.71)
Total Av. Gel
13.07°" (10.59)
9.46 b
(4.93) 7 .61 a b
(3.97) 7 .71 a b
(4.22) 7.25 a b
(2.55) 5.95 a
(3.11) strength
(std. dev) (n=50)
*values in a column (treatments) or in a row (days) with different superscripts are significantly different (p < 0.05)
75
Chapter 3. Results and Discussion
Table 11. Multiple R values for gel strengths and treatment factors
Day NaCI CaCI 2 Dilution Multiple
R 2
3 *(+) *(+) n/s 0.69
7 *(-) n/s n/s 0.37
14 *(-) n/s *(-) 0.60
28 n/s n/s *(-) 0.51
56 *(-) *(-) n/s 0.62
84 *(-) *(-) n/s 0.72
* denotes treatment factors that contributed to treatment effects (p < 0.05, n = ) (-) denotes a negative correlation between treatment factors and gel strengths (+) denotes a negative correlation between treatment factors and gel strengths n/s = not significant
76
Chapter 3. Results and Discussion
Table 12. Fold test scores of kamaboko gels (n = 5)
Treatments Day 3 Day 7 Day 14 Day 28 Day 56 Day 84 Total Av. Fold test (std.dev)
Fold test (std. dev)
Fold test (std.dev)
Fold test (std.dev)
Fold test (std.dev)
Fold test (std.dev)
Fold test (std.dev) (n=30)
1 6.0 (0.0)
5.6 (0.0)
5.2 (0.5)
. 4.6 (0.6)
5.2 (0.5)
5.4 (0.9)
5.3°"' (0-7)
2 6.0 . (0.0)
5.8 (0.5)
4.0 (0.0)
4.2 (0.5)
4.4 (0.6)
5.2 (1.1)
4.9b c
(0.9)
3 6.0 (0.0)
5.6 (0.6)
3.0 (0.0)
5.8 •(0.5)
6.0 (0.0)'
5.4 (0.6)
5.3cd
(1.1)
4 3.0 (0.0)
3.0 (0.0)
6.0 (0.0)
6.0 (0.0)
4.6 (0.6)
3.0 (0.0)
4.3 a b
(1.4)
5 3.0 (0.0)
3.0 (0.0)
3.0 (0.0) ;
3.0 (0.0)
5.8 "(0.5)
4.0 (0.0)
3.6a
(11)
6 3.0 (0.0)
6.0 (0.0)
5.6 (0.6)
3.0 (0.0)
3.0 (0.0)
3.0 . (0-0)
3.9a
(1.4)
7 4.4 . (0.6)
6.0 (0.0)
6.0 (0.0)
6.0 (0.0)
6.0 (0.0)
6.0 (0.0)
r 5.7d
(0.6)
8 5.6 (0.6)
5.8 (0.5)
4.8 (0.8)
5.6 (0.9)
4.4 (0.6)
4.4 (0.6)
5.1cd
(0.8)
9 . 6.0 (0.0)
5.8 (0.5)
6.0 (0.0)
6.0 (0.0)
5.4 (0.6)
5.0 (0.0)
5.7cd
(0.5)
Control 3.6 (0.0)
5.4 (0.6)
5.8 (0.5)
6.0 (0.0)
6.0 (0.0)
5.8 (0-5)
5.7cd
(0.5)
Total Treatment
Av. (std. dev)
(n=50)
4.8a* (1.3)
5.2a
(1.2) 4.9a
(1.2) 5.0a
(1.2) 5.1a
(1.0) 4.7a
(1.1)
*values in a column (treatments) or rows (days) with the same superscript are not significantly different (p < 0.05)
77
Chapter 3. Results and Discussion
Treaunent 4 reatinent 5 Treaunent 6
Lane 1 = day 84 Lane 2 = day 56 Lane 3 = day 28 Lane 4 = day 14 Lane 5 = day 7 Lane 6 = day 3
Treatment 7 Mol. Wl
treatments 1, 2, 3 are missing data 1 1 2 3 4 5 6
Treaunent 8 TreaUnent 9
Figure 18. S D S - P A G E Results
78
Chapter 4. Conclusion and future recommendations
Chapter 4 Conclusion and future recommendations
This study shows that it is possible to make high quality kamaboko from
solubilized treatments. Even more promising, this study shows that it is possible
to make solubilized treatments that are significantly better than surimi produced
by traditional methods (p <0.05). However, since this study lacks true replication,
further studies are required to confirm it's validity. For example, treatment 7
should be made again to see if its' results are reproducible. Future studies should
also include sensory panels so researchers can evaluate the marketability of
kamaboko from solubilized surimi.
It would be worthwhile to have a second control that consists of only solubilized
surimi with water and 8.30% cryoprotectants (no salt). Such a control would
allow one to examine the treatment effects of low levels of dilution and salts
compared to dilution alone.
Since no significant change in kamaboko quality was seen over time, future
solubilization studies should be conducted for a longer period of time to establish
a downward trend in storage keeping ability. Furthermore, it would be useful to
have more data points in the earlier stages of the study (day 0-7) in order to
develop meaningful regressions. It appears there are two trend lines on a given
plot when gel strength is plotted against time. However, the first trend line
79
Chapter 4. Conclusion and future recommendations
appears between days 3 and 7. Therefore, more points are needed during this time
period in order to do a spliced regression. ,
Consistency in sample homogeneity would also give credibility to this study.
Sample homogeneity would be facilitated by the use of proper commercial surimi
equipment.
Nevertheless, the results of this study are promising, and with further study,
solubilization may be a viable method for prolonging frozen storage of surimi.
80
Bibliography
Agri-Marine Industries Inc. Vancouver BC. September 1996. Personal communication.
Anon. 1991. A manual of standard methods for measuring and specifying the properties of surimi. National Fisheries Institute. Washington D.C. June 1991.
Anon. 1993. American Seafoods. Surimi processing manual. Quality specification and testing procedure. Rough draft.
An, H., Peters, M.Y., and Seymour, T.A. 1996. Roles of endogenous enzymes in surimi gelation. Trends in Food Science and Technology. 7:321-327.
Andres, C. 1987. Surimi poised for next step forward. 1987. Food Processing. 48: 28-38.
Babbit, J.K. 1986. Suitability of seafood species as raw materials. Food Technology. 3:97-100.
Bostian, M.L., Fish, D.L., Webb, N.B., and J.J. Arey. 1985. Automated methods for determination of fat and moisture in meat and poultry products: collaborative study. J.Assoc. Off. Anal. Chem. 68:876-880.
Bouraaoui, M.M. 1995. Surimi based product development and viscous properties of surimi paste. Ph. D thesis. University of British Columbia. Vancouver. BC.
Cavestany, M., Comenero, F., Solas, M.T., and Carballo, J. 1994. Incorporation of sardine surimi in bologna sausage containing different fat levels. Meat Science. 38:27-37.
Dora, K.C., and Hiremath, G.G. 1991. Surimi: a new scope for diversification of seafood exports. 1991. Seafood Export Journal. 23: 11-13.
Dou, J., Toma, S., and Nakai, S. 1993. Random-centroid optimization for food formulation. Food Research International. 26:27-37.
Greene, CW. 1926. The physiology of the spawning migration. Physiological reviews. 6:201-241.
Haard, N.F., Simpson, B.K., and Sun Pan, B. 1992. In Chapter 3: Sarcoplasmic proteins and other nitrogenous compounds. Seafood Proteins. Sikorski, Z.E., Sun Pan, B., and Shahidi, F. New York. Chapman and Hall. 13-29.
81
Hamada, M.1992. Mechanical behavior and cross linkages of heat induced myosin gel. Bull. Jap. Soc. Sci. Fish. 58:89-93.
Hamann, N.F., and MacDonald, G.A. 1992. In Chapter 17: Rheology and texture properties of surimi and surimi based foods. In Surimi Technology. Lanier, T.C. and Lee, C M . Marcel Dekker, Inc., New York, NY. 429-495.
Hashimoto, A., Kobayashi, A., and Arai, K. 1982. Thermostability of fish myofibrillar Ca-ATPase and adaptation to environmental temperature Bull. Jap. Soc. Sci. Fish. 48:671-684.
Helrich, K. 1990. Official Methods of Analysis of the Association of Official Analytical Chemists. 15th ed. AOAC Inc. Arlington, USA.
Holmes, K.L., Noguchi, S.F., and MacDonald, G.A. 1992. In Chapter 3. The Alaska pollack resource and other species used for surimi. In Surimi Technology. Lanier, T . C , and Lee, C M . Marcel Dekker, Inc., New York, NY. 41-75.
Howe, J.R., Hamann, D.D., Lanier, T .C, and Park, J.W. 1991. Fracture of Alaska pollack gels in water: effects of minced muscle processing and test temperature. Journal of Food Science. 59:777-780.
Hsu, C.K., Kolbe E., and English, M. 1997. A nonlinear programming technique to develop least cost formulations of surimi products. Journal of Food Process Engineering. 20:179-196.
Kennish, J.M., Sharp-Dahl, J.L., Chambers, K.A., Thrower, F., and Rice, S.D. 1992. The effect of a herring diet on lipid composition, fatty acid composition, and cholesterol levels in the muscle tissue of pen-reared chinook salmon (Onchoryhnchus tshawytscha). Aquaculture. 108:309-322.
Kim, B.Y., and Park, J.W. 1997. Rheology and texture properties of surimi gels. 5th
annual OSU technology school. J. Park. 88-125.
Kozak, T.A. 1997. Dean of Agriculture. University of British Columbia. May 1997. Personal communication.
Lanier, T.C. 1986. Functional properties of surimi. Food Technology. 40:107-114.
Lanier, T.C. 1992. In Chapter 10: Functional food protein ingredients from fish. Seafood Proteins. Sikorski, Z.E., Sun Pan, B., and Shahidi, F. New York. Chapman and Hall. 127-151.
•82
Lanier, T .C , Manning, P.K., Zetterling, T. and MacDonald, G.A. 1992. In Chapter 7: process innovations in surimi manufacture. Surimi Technology. Lanier, T .C , and Lee, C M . Marcell Dekker, Inc., New York, NY. 167-178.
Lanier, T.C. 1997. Surimi Chemistry. Ch.l. In surimi and surimi seafood manual. 5th annual OSU technology school. J. Park. 1-18.
Lee, C M . 1984. Surimi process technology. Food Technology. 38:69-80.
Lee, C M . 1985. A pilot plant study of surimi making properties of red hake. Paper no.20. International symposium on engineered seafood including surimi. Seattle Washington. Nov. 19-21.
Lee, C M . 1986. Surimi manufacturing and fabrication of surimi-based products. Food Technology. 40: 115-124.
Lee, C M . , Wu, M - C , and Okada, M. 1992. In Chapter 11: Ingredient and formulation technology for surimi-based products. Surimi Technology. Lanier, T . C , and Lee, C M . Marcel Dekker, Inc., New York, NY. 273-300.
Lee, C M . , Filipi, I., Xiong, Y., Smith, D., Regenstein, J., Damodaran, S., Ma, C-Y. and Haque, Z.U. 1997. Standardized failure compression test of protein gels from a collaborative study. Journal of Food Science. 62: 1163-1166.
Lin, T. Department of Food Science. University of British Columbia. Personal communication. Fall 1997.
Ma, L., Grove, A., and Barbosa-Canovas, G.V. 1996. Viscoelastic characterization of surimi gel: effects of setting and starch. Journal of Food Science. 61:881-889.
MacDonald, G.A. and Lanier, T.C. 1991. Cryoprotectants as cryoprotectants for meats and surimi. Food Technology. 45:150-159.
Mackie, I.M. 1993. The effects of freezing of flesh proteins. Food Review International. 9:575-610.
Marris, K. 1991. The surimi squeeze. Seafood Business. 11/12:40-43.
Mitchell, M.M. Director Operations (Chile). British Columbia Packers Ltd. October 1998. Personal communication.
Morris, C E . 1988. New product blends in surimi and meat. Food Engineering. 60: 49, 52.
83
Morrissey, M.T., Hartley, P.S. and An, H. 1995. Proteolytic activity in pacific whiting and effects of surimi processing. Journal of Aquatic Food Product Technology. 4: 24-37.
Nakai, S. 1990. Computer-aided optimization with potential application in biorheology. Journal of Japanese Society of Biorheology. 4:143-151.
Nakai, S., Nakamura, S., and Seaman, CH. 1998. Optimization of site-directed mutagenesis JJ. Application of random centroid optimization to one-site mutation of Bacillus stearothermophilus neutral protease to improve stability. Journal of Agricultural and Food Chemistry. 46:1655-1661.
Nishioka, F. 1984. Frozen surimi from sardines. Infofish-International. 1:31-34.
Noguchi, S., and Matsumoto, M. 1970. Studies on the control of the denaturation of fish muscle proteins during frozen storage I. Preventative effects of sodium glutamate. Bulletin of the Jap. Soc. of Sci. Fisheries. 36:1078-1087.
Ohshima T., Suzuki, T., and Koizumi, C. 1993. New developments in surimi technology. Trends in Food Sciences and Technology, 4: 157-16 3.
Okada, M. 1992. In Chapter 1: History of Surimi Technology in Japan. Surimi Technology. Lanier, T . C , and C M . Lee. Marcel Dekker, Inc. 3-20.
Park, J.W. 1994. Functional protein additives in surimi gels. Journal of Food Science. 59:425-527.
Park, J.W. 1995. Effects of salt, surimi and/starch content on fracture properties of gels at various test temperatures. J. Aquat. Food Product Technol. 4:75-84.
Park, J.W. and Morrissey, M.T. 1997. The need for developing uniform surimi standards. 5th annual OSU technology school. 64-70.
Pettinati, J.D. 1975. Microwave oven method for rapid determination of moisture in meat. Journal of the AO AC. 58:1188-1193.
Putro, S. 1989. Surimi: prospects in developing countries. Infofish Internationa] 5:29-32.
Reppond, K.D., Babbitt, J.K., Bernsten, S. and Tsuruta, M. 1995. Gel properties of surimi from pacific herring. Journal of Food Science. 60:707-710, 714.
Reppond, K.D., and Babbitt, J.K. 1997. Gel properties of surimi from various fish species affected by moisture content. Journal of Food Science. 62: 33-36.
84
Roussel, H. and Cheftel, J.C. 1988. Characteristics of surimi and kamaboko from sardines. International Journal of Food Science and Technology. 23:607-623.
Saeki, H. 1996. Gel-forming ability and cryostability of frozen surimi processed with CaC12-washing. Fisheries Science. 62: 252-256.
Saito, M., Durance, T., Dou, J., and Nakai. S. 1996. Optimization of storage conditions of surmi. 1996 IFT annual meeting book of abstracts, p. 132. ISSN 1082-1236.
Sikorski, Z.E. 1994. In Chapter 4: The myofibrillar proteins in seafoods. Seafood proteins. Sikorski, Z.E., Sun Pan, B., and Shahidi, F. New York. Chapman and Hall. 41-52.
Sikorski, Z.E. and Kodakowska, A. 1994. In Chapter 8: Changes in proteins in frozen stored fish. Seafood proteins.,Sikorski, Z.E., Sun Pan, B., and Shahidi, F. New York. Chapman and Hall. 99-107.
Sonu, S.C. 1986. National Oceanic and Atmospheric Administration Technical Memorandum National Marine Fisheries Service. S.W. Region. 1-113
Strugnell, C. 1989. A modified soxhlet procedure to determine fat in matured cheese. Irish Journal of Food Science and Technology. 13:71-75.
Tamota, T. 1971. Effect of leaching on the freezing denaturation of surimi proteins. New Food Industry. 13:61-69.
Toyoda, K., Kimura, I., Fujita, T., Noguchi, S., and Lee, C M . 1992. In Chapter 4: The surimi manufacturing process. Surimi Technology. Lanier, T . C , and Lee, C M . Marcel Dekker Inc., New York, NY. 79-110.
Whittle, K.J., and Hardy, R. 1992. In Chapter 12:Under-used resources- recent process innovations. Seafood Science and Technology. E.G. Bligh. Canadian Institute of Fisheries Technology. 101-115.
Yoon, W.B., Park, J.W., and Kim, B.Y. 1997. Linear programming in blending various components of surimi seafood. Journal of Food Science. 62:561-567.
Yongsawatdigul, J., Park, J.W., and E. Kolbe. 1997. Degradation kinetics of myosin heavy chain of pacific whiting surimi. Journal of Food Science. 62:724-728.
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