Effect of hydrolysis by various proteases on the dispersibility and solubility of soy protein isolate

Soy protein isolate (SPI) was slightly hydrolyzed by animal protease (pancreatin) , plant proteases (papain &bromelin) and microbe-proteases (alcalase&neutral proteinase) respectively, and the effect of hydrolysis on the dispersibility and solubility of SPI was systematically investigated.The results showed that the slight hydrolysis could improve the dispersibility obviously, while decrease the solubility significantly.As for the dispersibility, the three kinds of enzymes could be ranked according to the arrangement from high to low as follow:plant proteases >microbe-proteases>animal protease;and as for the solubility, the order was reversed.This study would have some reference value for preparing SPI with high dispersibility and solubility through enzymolysis.The results from the solubility of the insoluble fractions caused by papain hydrolyzation in the different solvents suggested that the hydrophobic area in the soy protein was exposed and promoted the forming of the precipitation.