Glycated whey protein concentrate for purple sweet potato anthocyanins delivery: Physicochemical stability and in vitro digestion characteristics

Glycated proteins are effective materials for improving the environmental stability and bioavailability of biologically active chemicals. The whey protein concentrate (WPC)-xylose (D) conjugates produced by the Maillard process were used to load and protect purple sweet potato anthocyanins in this study. Response surface optimization was used to determine the best parameters for preparing WPC-D conjugates. Glycation altered the secondary structure of proteins, according to structural studies, which also had an impact on their functional characteristics, which showed better antioxidant activity before and after simulated gastrointestinal (GI) digestion (p < 0.05). In the meantime, when compared to free anthocyanins (ANs) and heat-treatment of WPC-load ANs, WPC-D conjugates significantly improve ANs' stability to storage, thermal, light, metal ion, and hydrogen peroxide, while also increasing bioavailability and antioxidant activity during simulated GI digestion (p < 0.05). The results highlighted that the WPC-D conjugates are functional, promising, and useful hydrophilic bioactive carrier materials.