Abstract:In recent years, the interaction between protein and polyphenols has become one of the research hotspots in the field of food. The combination of protein and polyphenols is affected by many factors, among which the pH value is an important influencing factor. This article examines the influences of mulberry polyphenols (MP) on the physicochemical and functional properties of whey protein (WP) under different pH conditions. The results showed that MP changed the color, particle size and Zeta potential of complex protein powder. Meanwhile, the solubility and emulsifying properties of WP were also improved, and the emulsifying ability and emulsion stability of WP reached 7.23 m2/g prot and 89.56% at pH 3.0, which increased by 2.66% and 1.21%, respectively, compared with the control group. Quantitative analysis of monomeric phenolics in MP-WP powder was conducted by HPLC. The contents of bound monomeric phenolic compounds at pH 5.0 and 7.0 were higherthan those at pH 1.0 and 3.0. In addition, compared with the blank group, the addition of MP increased the DPPH free radical scavenging rate, ABTS free radical scavenging ability and FRAP reducing ability of WP, reaching the highest values, 89.28%, 81.70% and 530.95 μmol/g prot, respectively. In summary, the use of animal protein to bind plant polyphenols is a means of innovating functional food components, and the pH value of the reaction system has an important impact on the binding efficiency, which provides a new idea for the study of the physicochemical stability of food protein and the in vivo and in vitro bioavailability of nutrients.
