Preparation of Maillard reaction products of γ-polyglutamic acid and polydextrose and exploration of their physicochemical properties.

This study introduced polydextrose (PDX) into γ-polyglutamic acid (γ-PGA) through the Maillard reaction to form polymers with improved amphiphilicity and properties, and systematically investigated the effects of reaction conditions on the structure and performance of the products. The results showed that at a PDX/γ-PGA mass ratio of 1.0 and a heating temperature of 90 °C for 4 h, the degree of grafting (DG) reached a maximum of 88.53%, generated new functional groups (such as CN and CO), and increased particle size and morphological aggregation. Functional evaluation indicated that the emulsifying stability and foaming capacity were significantly enhanced, with foaming capacity being 7.7 times that of γ-PGA. In addition, The MRPs also achieved an encapsulation efficiency of 83.45% for astaxanthin and provided improved astaxanthin retention under ultraviolet irradiation and long-term storage. These findings demonstrate that Maillard reaction grafting with PDX is a feasible strategy for improving the interfacial functionality of γ-PGA and support the potential application of the resulting MRPs as emulsifiers and carriers for hydrophobic bioactive compounds.