Effect of Heat Treatment and Lyophilization on the Physicochemical Properties of Water-Soluble Proteins from Silver Carp (Hypophthalmichthys molitrix)

Abstract

The effect of heat treatment at different temperatures ranging from 30 to 80C on the physicochemical properties of water-soluble proteins from silver carp (Hypophthalmichthys molitrix) was investigated. Silver carp water-soluble proteins would suffer huge denaturation and aggregation from 40 to 55C. Both solubility and total sulfhydryl groups remained constant below 40C and sharply decreased from 50 to 55C. Surface hydrophobicity started to increase at 40C and reached maximum at 70C. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis of heated water-soluble proteins showed that the molecular weights of the main proteins ranged from 30 to 97 kDa. Most of silver carp water-soluble proteins precipitated at 55C. Lyophilization could increase surface hydrophobicity of water-soluble proteins, but decrease its solubility and sulfhydryl groups. Practical Applications The results indicate that the physiochemical properties of silver carp water-soluble proteins were greatly affected by processing and it would be a beneficial ingredient for functional food and pharmaceuticals at proper food processing conditions.