Characteristics of soy protein hydrolysate nanofibrils and their stabilization mechanism for Pickering emulsion: Interfacial properties, Rheology and stability

Abstract

Enzymatic hydrolysis is an effective method to improve the physicochemical properties of soy protein isolate (SPI) nanofibrils and expand their application in stabilizing Pickering emulsion. In this work, the effects of enzymatic hydrolysis on the SPI fibrillation and the stabilization mechanisms of SPI hydrolysate nanofibrils for Pickering emulsion were investigated. According to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) images and Thioflavin T (ThT) fluorescence data, a higher degree of hydrolysis (DH) contributed to releasing more small molecular weight peptides (mainly from α, α′, and β subunits) to improve apparent rate constant and surface hydrophobicity during fibrillation. When DH increased to 8%, SPI hydrolysate could form long and flexible nanofibrils and possessed the highest content of β-sheet (21.40%), when heated for 12 h. Enzymatic hydrolysis played various positive impacts on the interfacial properties of nanofibrils, including faster interfacial adsorption and near-neutral wettability (92.87°). SPI hydrolysate nanofibrils could impart enhanced gel-like structure and exceptional thermal stability to Pickering emulsions, resulting in a decrease in droplet size from 52.06 μm to 32.74 μm. This work will enhance the exploration of the formation mechanism of nanofibrils and broaden their application in the functional emulsion.