• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.4
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• pp.349-355
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• 1990

Actomyosine prepared from Yellowtail fish(seriola quinqueradiata) were stored at $0^{\circ}C$(ice-cooling) -3.5$^{\circ}C$(partial freeaing) and -2$0^{\circ}C$(freezing) Another actomyosin samples were prepared from the fish previously stored at the temperatures for a week as the maximum .Remaining activity of {{{{ {Ca }^{2+ } }}}}-and {{{{ {Mg }^{2+ } }}}}- dependent adenosine triphosphatase(ATPase) activity was measured fronm the actomyosin preparations. Specific activity of {{{{ {Mg }^{2+ } }}}}-ATPase of actomy-osin before storagew was 0.253$\mu$ mole pi/min/mg of protein and it was 1.5 times higher than that of {{{{ {Ca }^{2+ } }}}} -ATPase. The enzyme activities were markedly decreased during early period of storage. However no significant differences in the enzyme activity were revealed among the samples stored at different temperature. The enzyme of actomyosin prepared from the fish previously stored at the temperatures for a week revealed an acitivity of 2-3 times higher than that of freezing. Apparent denaturation constant of {{{{ {Mg }^{2+ } }}}} -ATPase of actomyosin was between 0.810-1.139 per day and it was about 1.5 times hgiher than that of {{{{ {Ca }^{2+ } }}}} -ATPase. But the constant of {{{{ {Mg }^{2+ } }}}} ATPase of actomyosin extracted from the fist stored for a week at each temperature was between 0.176-0.356 per day. This constant was 4 times higher than that of {{{{ {Ca }^{2+ } }}}}- ATPase in frozen stored fish. It was presumed from these results that denaturation of ATPase is largely accorded to the structural changes of actomyosin.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.371-379
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• 1988

To investigate on the biochemical characteristics of myofibrillar proteins between cold(pollack, salmon) and warm current fish (yellow corbina, shark), myofibrils and actomyosin were prepared, and their biological activities, effect of temperature on the myofibrillar ATPase activities and SDS-polyacrylamide gel electrophoretic patterns of myofibrils were compared. SDS-polyacrylamide gel electrophoretic analysis showed that electrophoretic patterns of myofibril vary from fish to fish. Difference in KCl concentration dependency of myofibrillar ATPase activities and ATPase activity- pH curve were found among fish species. Myofibrillar proteins from cold current fish showed higher specific activity at low temperature $(5^{\circ}C-10^{\circ}C)$ than those from warm current fish.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.199-202
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• 2008

The effects of $\beta$-(1,6)-galactosyl trehalose trisaccharide ($\beta$-GT) that was preferentially produced by Escherichia coli $\beta$-galactosidase on cryo- and thermo-protections of protein were investigated with those of other sugars at the level of 8% (w/v). As compared to a control without sugar additive, $\beta$-GT effectively enhanced 32-54% of the cryoprotection of fish actomyosin against repeated freeze-thawing and frozen storage, and also 49% of the protection against thermal inactivation of pyrophosphatase, respectively. As a result, it was significantly more effective than sorbitol and trehalose in both cryoprotection and thermoprotection. Thus, $\beta$-GT would be possibly applied as a sugar substitute for cryo- and thermo-protective applications of food protein.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.292-298
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• 1999

Myofibril and actomyosin were prepared from red muscle and white muscle of fresh water fish and sea water fish, and their biochemical characteristics and SDS PAGE patterns of myofibril were compared. SDS PAGE analysis showed that electrophoretic patterns of myofibril were similar be tween white muscle and red muscle, while difference of 30kDa component of myofibril was detected between fresh water fish and sea water fish. When myofibril were treated with trypsin, difference in hydrolysis of heavy chain was observed between white muscle and red muscle. In activities of Ca ATPase, Mg ATPase, EDTA ATPase and ATPase activity pH curve, myofibrillar protein from fresh water fish showed higher specific activity than those from sea water fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.823-828
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• 1998

The objective of this study is to investigate cryoprotective effects of corn starch enzyme hydrolysates of nonsweet and low-calories on denaturation of frozen fish protein. The cryoprotective effects of were examined in Alaska pollack actomyosin solution by changes in SDS-PAGE pattern, solubility, and $Ca^{2+}$-ATPase activity. When samples stored for 0 and 30 days were compared on SDS-PAGE patterns, severe changes in all bands were shown on the control sample regardless of storage temperature, especially in myosin heavy chain (MHC). Not much difference no appeared the electrophoretic pattern in case of the samples containing sucrose at any storage temperature during 30 days of storage. The cryoprotective effect of the hydrolysates were markedly dependant on storage temperature and no MHC band was found in the samples stored at $-5^{\circ}C$. The SDS-PAGE patterns of sample stored at $-20^{\circ}C$, however, completely maintained after 30 days or storage. When the samples were stored at $-5^{\circ}C$, the solubility of the sample containing sucrose was retained at $90\%$ after 30 days of storage, whereas dramatically decreased in other samples. The samples including sucrose, D.E. 10, 15, and 20 revealed $90\%$ in solubility when stored at $-20^{\circ}C$. The tendency of remaining $Ca^{2+}$-ATPase activity was almost shown the same as that of solubility.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.574-578
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• 2001

Myofibrillar proteins were prepared from red muscle and white muscle of fresh water fish and sea water fish, and their thermostabilities and effect of temperature on the myofibrillar ATPase activities were compared. Differences in temperature dependency of myofibrillar ATPase activities were found between two species. Thermodynamic data for inactivation of myofibrillar proteins, such as D value, Z value, $\Delta$ $H^{{\neq}}$, $\Delta$ $G^{{\neq}}$ and $\Delta$ $S^{\neq}$ revealed that thermostabilities of myofibrillar proteins from fresh water fish were higher than those from sea water fish, and that myofibrillar proteins from red muscle were more heat labile than those from white muscle.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.829-834
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• 1998

It is well known that the native conformation of many proteins can be stabilized by carbohydrates or polyalcohols. However, the mechanism of the stabilization still remains unclear. In the present studies, to characterize the cryoprotective mechanism of corn starch enzyme hydrolysates on fish protin, solubility of hydrolysates, thermal behavior of hydrolysates and actomyosin solution, and enzyme kinetics in frozen system were investigated. The solubility of the hydrolysates increased with the increase in D.E. value. The $T_g^{'}$ of the hydrolysates were linearly correlated with D.E. value and the T-g value of the hydrolysates (D.E. 5,10,15,20) were reported to be $-7.2^{\circ}C\;-8.8^{\circ}C\;-11.9^{\circ}C$, and $-14.3^{\circ}C$, respectively. The results of enzyme experiments showed that the higher the D.E. value, the higher was the rate of reaction in frozen storage ($-12^{\circ}C$). It is found to support the cryostabilization mechanism that the hydrolysats act to enmesh the protein in a glass state where all deteriorative processes are greatly slowed down.