Changes in Physicochemical and Biological Properties of Polyphenolic-Protein-Polysaccharide Ternary Complexes from Hovenia dulcis after In Vitro Simulated Saliva-Gastrointestinal Digestion

The present study aimed to explore the impacts of in vitro simulated saliva-gastrointestinal digestion on physicochemical and biological properties of the polyphenolic-protein-polysaccharide ternary complex (PPP) extracted from Hovenia dulcis. The results revealed that the in vitro digestion did remarkably affect physicochemical properties of PPP, such as content of reducing sugar release, content of bound polyphenolics, and molecular weight distribution, as well as ratios of compositional monosaccharides and amino acids. In particular, the content of bound polyphenolics notably decreased from 281.93 ± 2.36 to 54.89 ± 0.42 mg GAE/g, which might be the major reason for the reduction of bioactivities of PPP after in vitro digestion. Molecular weight of PPP also remarkably reduced, which might be attributed to the destruction of glycosidic linkages and the disruption of aggregates. Moreover, although biological activities of PPP obviously decreased after in vitro digestion, the digested PPP (PPP-I) also exhibited remarkable in vitro antioxidant and antiglycation activities, as well as in vitro inhibitory effects against α-glucosidase. These findings can help to well understand the digestive behavior of PPP extracted from H. dulcis, and provide valuable and scientific supports for the development of PPP in the industrial fields of functional food and medicine.