Cryoprotective Effect and Mechanism of Corn Starch Enzyme Hydrolysates on Fish Protein 2. Cryoprotective Mechanism of Corn Starch Enzyme Hydrolysates on Fish Protein

전분가수분해물의 어육단백질 동결변성 방지효과 및 작용기구 2. 옥수수전분가수분해물의 어육단백질에 대한 동결변성 방지 기구

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.

옥수수 전분가수분해물의 용해도는 D.E. 값이 높을수록 증가하였고, 10 이상에서는 거의 차이가 없었다. $T_g^{'}$ 값은 D.E. 값이 증가함에 따라 감소하는 직선적인 관계를 나타내었다. Alkaline phosphatase의 동결계에서 거동은 glass cynamic mechanism, 즉 효소의 가수분해 속도는 첨가된 물질의 $T_g^{'}$ 이하의 온도에서 지연되거나 억제되었다. 옥수수전분 가수분해물은 동결계에서 유리전이온도를 높임으로서 동결계가 유리상태로 되고 따라서 점도는 높아지고 단백질은 분자간 접촉의 기회가 줄어들어 단백질이 보호된다는 cryostabilization mechanism으로 설명 가능하였다.