CA2001244C - Process for processing fish meat contaminated with sporozoa - Google Patents

Abstract

A process for processing fish meat having jelly meat due to contamination with sporozoa as a raw material, the process comprising adding to the fish meat a material selected from the group consisting of plasma protein, serum protein, serum globulin and mixtures thereof.

Description

1~2001 24 4 PR~CESS FOR PROCESSING FISH MEAT
CQNTAMINATED WITH SPOROZOA
BACKGROUND OF THE INVENTION
This invention relates to a process for processing fish meat or fish flesh. More particularly, it relates to a process for processing fish meat having a tendency to form jelly meat or jellied meat due to contamination with sporozoa by adding a material selected from the group consisting of plasma protein, serum proteinr serum globulin and mixtures thereof to the fish meat, whereby it is possible to produce "neriseihin"
~fish meat paste products) having good elasticity from the fish meat having a tendency to form jelly meat, which otherwise cannot be used as a raw material for "neriseihin" because of its lack of gel-forminy capability.
In a fish on which minute sporozoa (mucilaze sporozoa) belonging to the class of protozoa are parasitic, fish meat protein is decomposed by a proteolytic enzyme released by the sporozoa after death of the fish. Particularly, when heating is carried outr the fish meat is spottily or wholly softened and ~0 liquified in the form of a jelly. This forms so-called jelly meat. This jelly meat represents a great problem in the fishery field. When "surimi" (minced meat) is prepared from the fish meat having a tendency to form jelly meat, the proleolytic enzyme derived from the sporozoa acts on myosin, i.e., muscle protein which is a major gel-forming component of "neriseihin"
on heating, and thus decomposes the myosin. Therefore, the raw fish meat having a tendency to form jelly meat exhibits no gel-forming capability. The sporozoa to which jelly meat is as-,~

~20 0 1 24 4 ~ 20375-644 cribable belong to the unicapsla genus, ~hloromyxum genus~
Kudoa genus and the like of Myxosporida which belongs to Cnidosporidae, Sporozoa of Protozoa. These sporozoa are never parasitic with respect to human beings. Accordingly, when the sporozoa and fishes on which sporozoa are parasitic are eaten, there has keen no incidence of health trouble attributable to sporo~oa. A "neriseihin" which is subjected to heat treatment presents no problems from the standpoint of food sanitation.
Various processes for solving problems of fish meat processing having a tendency to form jelly meat have heretofore been proposed. For example~ U.S. Patent No. 4,207,354 discloses a process for adding egg white to fish meat having a tendency to form jellied meat. Further, IJ.S. Patent No. 4,284,653 discloses a process for adding a substance which inhibits thiol protease to fish meat haviny a tendency to form jellied meat. Further-more, Japanese Patent Laid-Open Publication No. 42567/1981 discloses a process for contacting fish meat having a tendency to form jelly meat with an oxygen acid-type oxidant or SH
reagent. Moreover, Japanese Patent Laid-Open Publication No. 24872/1988 discloses a process for adding a milk component of a mammal to fish meat having a tendency to form jelly meat. Furthermore, Japanese Patent Laid-Open Publication No. 74446/1988 discloses a process for applyin~ pressure to fish having tendency to form jelly meat, thereby inhibiting the formation of jelly meat.
While considerable effects are obtained according to the prior art processes, such processes are not entirely satisfactory. We have carried out studies in order to find a ~'A' ~' ~ 2 o ~ ~ 2 4 ~

materlal whereln a small amount of such a materlal can lnhlblt sporozoa enzyme from actlng on a raw material of flshes havlng a tendency to form ~elly meat, and whereln good processed products can be produced therefrom. We have now found that lncorporatlon of a sultable amount of a materlal selected from the group con-slstlng of serum proteln, serum globulln and mlxtures thereof ln flsh meat havlng a tendency to form ~elly meat due to contamlnatlon wlth sporozoa lnhlblts proteolytlc enzyme of sporozoa and provldes good flsh meat processed products such as "surlml" and "nerlselhln".
SUMMARY OF THE INVENTION
Accordlngly, the process for processlng flsh meat accordlng to the present lnventlon comprlses addlng a materlal selected from the group conslstlng of serum proteln, serum globulln and mlxtures thereof to flsh meat of flshes havlng a tendency to form ~elly meat due to contamlnatlon wlth sporozoa.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 ls a graphlcal dlagram showlng the electro-phoresls patterns of varlous samples obtalned by carrylng out electrophoresls ln Test Example 2 of the present lnventlon.
DETAILED DESCRIPTION OF THE INVENTION
Flshes whereln ~elly meat ls llkely to be formed because of parasltlsm of sporozoa lnclude North Paclflc hake (Merlucclus productus), Chllean hake (Merlucclus gayl) and Argentlnean hake (Merlucclus hubbsl) of Merlucclus; flatflsh, bastard hallbut, tuna, marlln, baracuda, salmon, common sea 2 0 0 1 2 ~ 4 bass, flylng flsh and common dolphln. Flshes whlch can be processed accordlng to the present lnvention are not llmlted to the klnd of flshes llsted above.
Sporozoa cannot be lntrlnslcally observed by the naked eye. When the degree of parasitlsm ls lncreased, a number of sporozoa are clustered to form a bag-shaped matter generally called a cyst, and a sporozoan cyst havlng a slze vlslble to the naked eye ls formed. In the case of North Paclflc hake, a cyst ln the form of black halr ls observed at the flllet surface when the percentage of parasltlsm of sporozoa ls hlgh. In the case of Peruvlan hake, a black or whlte cyst ls observed and the percentage of parasitlsm can be from 14 to 40% dependlng upon the slze of a flsh body and the place where lt was caught. Flsh meat on which sporozoa havlng a hlgh concentratlon are parasltlc can be used as a raw material ln the present lnvention.
In the present invention, a material selected from the group conslsting of serum proteln, serum globulln and mlxtures thereof ls added to fish havlng a tendency to form ~elly meat due to contamlnatlon with sporozoa. As ls well known, plasma protein is a proteln component ln a llquld component obtalned by removing visible components such as leukocyte, erythrocyte and thrombocyte from blood. A
materlal remalnlng after flbrlnogen present ln the plasma proteln ls coagulated and deposlted ls serum proteln.
Albumln, globulln and the llke are contalned ln the serum proteln. It ls observed that a substance present ln the serum protein which particularly effectlvely acts as a ,~

~ 2~û~244 substance whlch inhlbits protease ln the present lnventlon ls globulln.
Serum proteln and serum globulin as used hereln are generally prepared from blood of varlous domestlc anlmals and flshes. For example, a powder obtalned by sampllng blood from domestlc anlmals such as cattle, plgs, horses, sheep, goats, chlckens and ducks, and flshes such as sea breams and young yellowtalls ls used, separatlng a predetermlned component from the blood, and drylng lt. Of these, serum proteln of cattle and plgs ls preferably used. The serum proteln ls generally avallable at low cost.
An example of a process for separatlng blood components wlll now be descrlbed. Sodlum cltrate ls added to sampled blood to prevent coagulatlon. When the centrlfuged supernatant ls drled, a sllghtly llghtly yellowlsh brown powder of plasma proteln is obtalned. After blood sampllng, the blood ls allowed to stand at 5~C, and mass-shaped aggregate of blood cell and flbrln ls centrlfuged to remove them to obtain an amber supernatant. Thls supernatant ls lyophlllzed to obtaln llghtly yellow powdered serum proteln.
The serum ls sub~ected to saltlng out by a 50% saturated ammonlum sulfate solutlon and thereafter centrlfuged to collect the same. The centrlfuged serum ls dlalyzed by a O.lM sodlum chlorlde solutlon, and the dlalyzate ls lyophlllzed to obtaln a sllghtly graylsh whlte powder of serum globulln.
In general, when "surlml" or "nerlselhln" ls prepared, flsh meat ls sub~ected to debonlng, leachlng and ~, 2 ~ O 11 2 4 4 dehydratlon, and ad~uvants such as sugars and polyphosphates are added to the dehydrated meat. The resulting mlxture is kneaded and thereafter formed into fresh "surimi" or further frozen to form a frozen "surimi". To this fresh "surimi", or "surimi" which has been thawed ln the case of the frozen "surlmi", are added additlves such as starch, salt and seasoning. The resulting mixture ls ground, kneaded, formed into a specific product, and heated to obtain a fish meat "neriselhln".
The stage of adding the thus obtained serum or serum globulin to the fish meat having ~elly meat ln the present lnventlon may be any step ln the "suriml" production process and may be any step before heatlng in the case of the fish meat "neriselhln" production process. It is preferable that the serum proteln or serum globulin be added when the flsh meat is sub~ected to leaching in producing "suriml", or when ad~uvants are incorporated ln the dehydrated meat or when kneadlng is carrled out in processing "neriseihin".
The amounts of the serum protein and/or serum globulln added to fish meat having ~elly meat ln the present lnventlon are as follows. The amount of the serum proteln added ls from 0.01 to 10 parts (preferably from 0.5 to 3 parts) (on a dry basls) based on 100 parts of raw flsh meat.
The amount of the serum globulln added ls from 0.001 to 10 parts based on 100 parts of raw fish meat. Small amounts of these components are sufficient.
If the amount of the serum protein or serum globulln fraction added ls less than the lower llmlt, the ~ 2~0~1 ~4 4 6a actlvity of sporozoa enzyme cannot be lnhlbited, and a raw materlal for "nerlseihln" havlng sufflclent gel elastlclty cannot be prepared. If the amount added ls greater than the upper llmlt, blood odor wlll be lncreased, the degree of coloration wlll be lncreased and the flavor and taste of the fish meat product wlll be lowered.
The following examples lllustrate preferred embodiments of the present invention as well as similar processes. Plasma proteln, serum proteln and serum globulin descrlbed herelnafter are prepared from bovlne blood. Parts and percentages are by welght. In the following examples, the ~elly, strength representlng a physlcal property of a gel formlng abllity ls expressed as J.S. (g-cm) obtalned by multiplylng the rupture strength (W value (g)) measured by uslng a 5 mm-dlameter plunger wlth a round end by food checkers by the dlstance of the concave up to rupture (L
value (cm)).
Organoleptlc evaluatlon of a "kamaboko"-shaped gel was carrled out uslng the followlng 10-stage evaluatlon.
("kamaboko" ls a paste plled up on a thln rectangular wooden board).
Foldlng Test The speclmens used were cut lnto round sllces havlng a thlckness of 3 mllllmetres and folded between thumb and lndex flnger.
Score 10: when the specimen is folded into quarters and strongly pushed, no crack occurs;
9 when the speclmen is folded lnto quarters and ~ ~001244 6b strongly pushed, cracks are formed;
8: when the speclmen ls folded lnto quarters and sllghtly pushed, cracks are formed;
7: when speclmen ls folded lnto quarters and the whole ls caused to contact together, cracks are formed;
6: when the speclmen ls folded lnto quarters and the whole ls llghtly put together; crack~ are lmmedlately formed;

2 0 0 ~ 2 4 5: when the specimen is folded into two halves and the whole is put together, cracks are formed within the one-half portion;
4: when the specimen is folded into two halves and the whole is put together, cracks are formed in the whole;

3: when the specimen is folded into two halves and the whole is liyhtly put together, cracks are immediately formed;
2: when the specimen is pushed with the finger, it is breakable; and 1: the specimen does not cohere.
Biting Feel Test The specimens used were cut into round slices having a thickness of 5 milimeters. Firmne,s,s and sensory were scored by the bite test.
Score 10: extremely strong and flexible;
9: very strong and flexible;
8: considerably strong;
7: slightly strong;
6: the strength is generally good;
5: while t,he strength is generally good, the specimen is slightly brittle;

4: slightly weak and considerably brittle;
3: weak and brittle;
2: extremely weak, and 1: the specimen does not cohere.

. Z O 0 1 ~ 4 ~
.
1a 20375-644 Test Example l As a raw material, North Pacific hake was used. It had an average body weight of 520 grams, wherein about 16~ of a cyst in the form of black hair exhibiting likelihood to form jelly meat due to contamination with sporozoa was observed. The hake was subjected to deboning, leaching and dehydrated. Sugar and a phosphate were added to the dehydrated hake. The mixture was frozen to prepare a frozen "surimi" of North Pacific hake.
This "surimi" was thawed7 and thereafter 3% of salt, 3% of potato starch ~"~

ZOOlZ44 and 1% of a powder of plasma protein, serum protein or serum globulin were added to the "surimi". The mixture was kneaded. A polyvinylidene chloride tube was filled with the kneaded mixture. The mixture was heated for 40 5 minutes at 90~C and cooled. Its jelly strength was measured. A gel containing no plasma protein, serum protein or serum globulin was prepared as a control, and its jelly strength was measured.
The results are shown in Table 1.

Amount Jelly No. Additive added strength Folding F lg (%) (g-cm) 1 none 0 142 2 2 2bovine plasma 1 930 10 10 protein 3bovine serum 1 990 10 10 protein 4bovine serum 1 1300 10 10 globulin In the case of the gel containing no plasma protein, serum protein or serum globulin, the jelly strength is 25 very low (i.e., 142 g cm), cracks are easily formed in twofold condition and the gel exhibits an inferior mouth feel. On the other hand, gels containing plasma protein, serum protein or serum globulin exhibit a jelly strength of at least 900 g-cm. Thus, such gels exhibit good gel 30 physical properties.
Test Example 2 A frozen "surimi" of North Pacific hake contaminated with sporozoa used in Test Example 1 was thawed.
Thereafter, 3% of salt, 3% of potato starch and from 0.5 35 to 3~ of bovine plasma protein were added thereto. The resulting mixture was kneaded and a polyvinylidene chloride tube was filled with the mixture. The mixture 20(~1Z4~

was heated for 40 minutes at 90~C and cooled. The jelly strength of this "surimi" processed product and the pattern of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (hereinafter referred to as SDS-PAGE) 5 were measured. The measurement of the SDS-PAGE pattern makes it possible to observe how the molecular shape of "surimi" protein varies in producing a "surimi"
processed product. The SDS-PAGE method was carried out according to a Weber-Osborne's method using 10%
10 acrylamide gel-0.1% SDS. The solubilization of a "kamaboko" gel was carried out by mincing the "kamaboko" gel by means of a Potter hand homogenizer, and adding 2% SDS, 8M urea, 0.1M Tris-glycine and 5 mM ~-mercaptoethanol as solubilizing agents to prepare a 15 sample for electrophoresis. After electrophoresis, dyeing of protein was carried out by using Coomassie Brilliant Blue.

Amount of Jelly No bovine plasma strength Folding Biting protein added Feel (%) (g-cm) 1 none 199 2 2 2 0.5 718 9 9 3 1.0 949 10 10 4 2.0 996 10 10 3.0 1190 10 10 With at least 0.5% of bovine plasma protein, good gel strength was obtained. The obtained electrophoresis patterns are shown in FIG. 1. Pattern (1) shows a pattern of North Pacific hake "surimi" without heating;
3 and Patterns (2) through (6) show electrophoresis patterns of "kamaboko-like" gels of Nos. 1 through 5 of Table 2, respectively.

zoa~

As can be seen from electrophoresis Pattern (2), in the case of sample No. 1 containing no bovine plasma protein, myosin, i.e., major protein of the North Pacific hake "surimi" is decomposed by protease derived from 5 sporozoa contained in the "surimi" to form small pieces.
This corresponds well to the fact that the jelly strength is very low, i.e., 199 g cm. As can be seen from SDS-PAGE Patterns (3) through (6) of "kamaboko" gels containing from 0.5% to 3% of bovine plasma protein, the 10 extent of decomposition of myosin is reduced with increase in the amount of plasma protein added. In the case of Pattern (6), substantially no myosin is decomposed. The extent of decomposition of myosin observed in SDS-PAGE Patterns (3) through (6) corresponds 15 well to their jelly strength.
That is, the bovine plasma protein acts as an inhibitor for protease of sporozoa, and the decomposition of "surimi" protein by protease of sporozoa in producing and processing "surimi" is inhibited. Thus, Test Example 20 2 demonstrates that "surimi" processed products having good gel physical properties can be produced from the "surimi" of North Pacific hake.

North Pacific hake contaminated with sporozoa used 25 in Test Example 1 was dressed, and deboning was carried out. The North Pacific hake was subjected to mincing treatment to form a material in the form of ground meat.
To this material were added 2% of salt, 5% of potato starch, 2% of sugar, 0.5~ of seasoning and 1% of a bovine 30 plasma protein powder. The mixture was lightly kneaded and formed into balls. These balls were boiled for 10 minutes at 100~C. Fish balls containing no bovine plasma protein powder were prepared as a control. The fish balls containing no bovine plasma protein formed "tumire"
(a spongy product), and the resulting product exhibited a significantly inferior mouth feel. The fish balls containing bovine plasma protein had such physical properties that there was good sensory resistance to the teeth when bitten, it was noticed that the effects of the bovine plasma protein were remarkable.

Chilean merluccius (Merluccius gayi) having an average body weight of 623 grams and contaminated with sporozoa was used as a raw material. It was subjected to deboning, leaching and dehydration. To this dehydrated meat were added 7% of sugar, 0.2% of a polyphosphate and 2% of bovine plasma protein. The resulting mixture was kneaded, and frozen to form a frozen "surimi". A
frozen "surimi" containing no bovine plasma protein was prepared as a control. The "surimis" were stored for 4 months at -25~C and thereafter an "itazukemushi-kamaboko"
(a steamed paste piled up on a thin rectangular wooden board) was prepared therefrom. The "itazukemushi-kamaboko" was prepared as follows. 100 Kg of frozen "surimi" was thawed and thereafter 3 kg of salt, 5 kg of "mirin" ("mirin" being a kind of wine used as seasoning in Japan), 5 kg of corn starch, 60 kg of water, and 1.4 kg of seasoning were added thereto. The mixture was kneaded by means of a silent cutter and formed into an "itazuke-shaped kamaboko". This was heated for one hour in a steamer. While "kamaboko" obtained by using the frozen "surimi" containing bovine plasma protein exhibited a mouth feel similar to that of "itazuke-shaped kamaboko" obtained by using a conventional Alaska pollack "surimi", the "surimi" containing no bovine plasma protein formed "tumire" and "kamaboko" was not produced.

As a raw material, L-size yellowfin-sole was used.
It had a parasism percentage of 18% wherein sites on which sporozoa were parasite were dissolved and removed in the form of spots when the flatfish was heated. The flatfish was dressed, and its skin was removed by means of a peeling machine. The treated flatfish was subjected to deboning by means of a deboner, leaching and dehydration. To this dehydrated meat were added 5% of sugar, 0.2% of a polyphosphate and 3% of a bovine serum protein dried powder. These materials were mixed, and the mixture was frozen to form a frozen "surimi". A
5 frozen "surimi" containing no bovine serum protein dried powder was prepared as a control. These frozen "surimis"
were stored for 6 months at -25~C. These were thawed, and 3% of salt and 3% of potato starch were added thereto. The resulting mixtures were kneaded, and 10 polyvinylidene chloride tubes were filled with the kneaded mixtures. The mixtures were boiled for 40 minutes at 90~C and cooled. Their jelly strength was measured. Their mouth feel and flavor and taste were examined.

Amount of plasma Y Biting . M th Flavor No. strength Foldlng and protein Feel feel (g cm) taste added (%) 1none (O) 136 2 2 poor good 2 3 865 9 9 good good 25It was apparent that, even if the bovine serum protein is previously added to the "surimi" and frozen, this serum protein exerts superior effects, its biting property and mouth feel are superior to those of the product containing no bovine serum protein and that its 30 flavor and taste are comparable to those of the product containing no bovine serum protein. ~-When the plasma protein, serum protein or serum globulin is added to the fish meat having jelly meat due to contamination with sporozoa, and the fish meat is 35 treated therewith according to the present invention, its plasma protein and the like inhibit the protease of the sporozoa, and thus a good "neriseihin" having gel-forming 200~244 capability can be produced. Further, the plasma protein and the like used are obtained at low cost, and are effective in a small amount. Accordingly, the desired products can be economically produced and thus the 5 process of the present invention is extremely effective for such products.

Claims (12)

1. A process for processing fish meat having a tendency to form jelly meat upon heating due to contamination with sporozoa as a raw material, which process comprises adding to the fish meat a material selected from the group consisting of serum protein, serum globulin and mixtures thereof, wherein when the serum protein is employed, it is added in an amount of from 0.01 to 10 parts by weight (on a dry basis) based on 100 parts by weight of the raw fish meat, and wherein when the serum globulin is employed, it is added in an amount of from 0.001 to 10 parts by weight (on a dry basis) based on 100 parts by weight of the raw fish meat.

2. The process according to claim 1 wherein the serum protein and serum globulin are in the form of a dried powder obtained from the blood of domestic animals or fishes.

3. The process according to claim 1 or 2, wherein at least one of the serum protein and serum globulin is added when the meat is subjected to leaching or when an adjuvant is kneaded into the dehydrated meat after the meat has been subjected to leaching in producing minced fish meat.

4. The process according to claim 1 or 2, wherein at least one of the serum protein and serum globulin is added when an additive is added to the fresh minced fish meat or frozen minced fish meat which has been thawed, and the mixture is kneaded during a fish paste product processing operation.

5. The process according to claim 1 or 2, wherein the serum protein is added in an amount of from 0.5 to 3 parts by weight (on a dry basis) based on 100 parts by weight of the raw fish meat.

6. The process for processing raw fish meat having a tendency to form jelly meat upon heating due to contamination with sporozoa, which process comprises:
(1) subjecting the raw fish to deboning, leaching, dehy-dration, adjuvant addition, kneading and forming into minced fish meat, and (2) subjecting the minced meat to additive addition, grinding, kneading, forming and heating to obtain a fish meat paste product, wherein at any stage before the heating, a material selected from the group consisting of serum protein, serum globulin and mixtures thereof is added to the fish meat, wherein when the serum protein is employed, it is added in an amount of from 0.01 to 10 parts by weight (on a dry basis) based on 100 parts by weight of the raw fish meat, and wherein when the serum globulin is employed, it is added in an amount of from 0.001 to 10 parts by weight (on a dry basis) based on 100 parts by weight of the raw fish meat.

7. The process according to claim 6, wherein sugar and polyphosphate are employed as the adjuvant.

8. The process according to claim 7, wherein starch, salt and seasoning are employed as the additive in step (2).

9. The process for processing raw fish meat having a tendency to form jelly meat upon heating due to contamination with sporozoa, which process comprises:
subjecting the raw fish to deboning, leaching, dehydration, adjuvant addition, kneading and forming into minced fish meat adapted to be further processed into a fish meat paste product including a heating step, wherein at any stage until the minced fish meat is formed, a material selected from the group consisting of serum protein, serum globulin and mixtures thereof is added to the fish meat, wherein when the serum protein is employed, it is added in an amount of from 0.01 to 10 parts by weight (on a dry basis) based on 100 parts by weight of the raw fish meat, and wherein when the serum globulin is employed, it is added in an amount of from 0.001 to 10 parts by weight (on a dry basis) based on 100 parts by weight of the raw fish meat.

10. The process according to claim 9, wherein sugar and polyphosphate are employed as the adjuvant.

11. The process according to any one of claims 6 through 10 wherein the serum protein and serum globulin are in the form of a dried powder obtained from the blood of domestic animals or fishes.

12. The process according to claim 11, wherein the serum protein and serum globulin are obtained from cattle blood.