Insight into functionality and bioactive properties of whey protein/beta-glucan complex discrepancy during different pH-induced phase transition

Abstract

This study aimed to elucidate the differences in functional and bioactive properties of whey protein isolate(WPI)-oat beta-glucan(OBG) mixed system during pH-induced phase transition. Four representative phase regions were identified, including co-soluble region at pH 2.0 (CSRpH2.0), soluble complex region at pH5.5 (SCRpH5.5), and insoluble complex region at pH 4.5 (ISRpH4.5) and co-soluble region at pH 7.0 (CSRpH7.0). The WPI-OBG mixture (WG) in CSRpH2.0 had the highest content of irregular secondary structures compared to the other phase regions. WG in SCRpH5.5 possessed higher foaming and emulsifying properties than that in ISRpH4.5. Compared with other phase regions, WG in CSRpH2.0 exhibited superior in vitro bioactivity. The principal component analysis showed WG in CSRpH2.0 had the highest comprehensive scores compared with those in other phase regions. The elucidation of differences in functionality and bioactive properties among protein-polysaccharide complexes from different phase regions provide a key theoretical basis for their targeted application in food industry.