Functional properties analysis of the frozen soybean protein isolate gel

The texture, soluble protein content and constitution, and microstructure of SPI gel with or without freezing were analyzed.The results showed that the hardness of frozen SPI gel increased, while elasticity, water binding capacity, soluble protein content decreased.SDS-PAGE showed that after frozen treatment, γ subunit disappeared and A subunit increased.The result of SEM showed that water in the gel congealed and grew into bigger ice crystals, which made the tight structures turned into net structure full of holes.