Effects of Ethanol-induced Modification on the Structural and Emulsifying Properties of Whey Protein Isolates

This study took the whey protein isolation(WPI)without the treatment of ethanol solution as the control group to investigate the effect of different concentrations of ethanol(10%,30%,50%,and 70%,v/v)on the structural properties and emulsifying capacities of whey protein isolate(WPI). The results showed that the ethanol-induced modification could significantly alter the secondary and tertiary structures of WPI. Moreover,lower concentration(less than 50%)of ethanol could induce the unfolding of the protein structure of WPI,while higher concentration(more than 50%)of ethanol could promote the protein aggregation which mainly through disulfide linkage. Additionally,compared with control group,ethanol-induced modification could endow higher surface hydrophobicity and better emulsifying capacities(including emulsifying activity and emulsifying stability)of WPI,and 50% was the optimal ethanol concentration. This results indicated that the ethanol-induced modification was an effective modification method to improve the emulsifying properties of WPI and laid a theoretical foundation for the modification of proteins.