Effect of succinic anhydride and acetic anhydride on the emulsifying properties of soybean protein isolate

Objective:The effect of chemical modification on the emulsifying properties of soybean protein isolate(SPI)was studied in this paper;Methods:Acetylation and succinylation were used as modification reagents;Results:The modification degree increased as the levels of succinic anhydride or acetic anhydride added to the protein increased.The modification rate with acetic anhydride was greater than with succinic anhydride at all levels used.The emulsifying protein index and emulsifying stability of SPI were both enhanced with the increase of modification extent.In the range of neutral and weak alkaline pH(5.0～8.0),acetylation and succinylation both caused a significant increase in EAI and ES.And the EAI and ES of succinylated SPI was improved greater than that of acetylated SPI.However,the effect of ionic strength on the emulsifying properties of SPI was negative;Conclusion:Acetylation and succinylation both improved the emulsifying properties of SPI significantly.And the emulsifying properties of succinylated SPI were improved greater than that of acetylated SPI.