Abstract:In order to study the relationship between the changes of macrostructure properties of soybean protein and the micro aggregation behavior during freezing，soybean protein isolate （SPI）solution was used as raw material，which was freeze induced at-5℃ and-20℃ and then dried and dissolved again.The effects of concentration of soybean protein solution，freezing induction temperature and time on the aggregation of soybean protein were studied.The aggregation behavior of SPI was analyzed by solubility，turbidity and other indicators.The micro molecular structure of SPI was analyzed by scanning electron microscope and stability kinetic index.The results showed that there was a negative correlation between the freezing time and the solubility of SPI.The solubility of SPI reached the lowest at-5 ℃ for 5 days，which was only（47.62±1.04） %.The results showed that the turbidity of soybean protein isolate was the highest 0.79 at 5 % SPI concentration；the content of disulfide bond increased with the increase of concentration of soybean protein isolate solution.When the concentration of soybean protein isolate solution was 6 %，the maximum content of disulfide bond was（26.54±0.78）μmol/g；with the deepening of freeze-induced degree，the solubility of protein decreased，turbidity increased，protein aggregation，resulting in its microstructure from sparse to dense，becoming more stable.