Changes in physiochemical properties of water-soluble proteins from crucian carp (Carassius auratus) during heat treatment

In order to understand physicochemical properties of water-soluble proteins obtained from crucian carp, turbidity, total sulfhydryl content, hydrophobicity and SDS-PAGE of crucian carp water-soluble proteins during heat treatment were investigated. Turbidity remained unchanged up to 44°C and considerably increased from 46°C to 54°C, one peak of increase rate was found at 50°C; total SH content decreased rapidly when heated from 50°C to 55°C; hydrophobicity increased sharply when heated up to 45°C, indicating the conformation of water-soluble proteins from crucian carp began to unfold and expose the buried nonpolar amino acids at temperatures above 45°C; analysis of SDS-PAGE indicating the formation of disulfide linkage of creatine kinase and glyceraldehy-3-phosphate dehydrogenase when the temperature reached 65°C and 80°C, respectively.