Effect of in vitro simulated gastrointestinal digestion on polyphenol and polysaccharide content and their biological activities among 22 fruit juices

Polyphenols and polysaccharides, as natural bioactive compounds from common fresh fruits, are concerned in reducing risk of developing obesity and diabetes for human in recent years. The content of polyphenol and polysaccharide, their bioactivities among 22 fruit juices were investigated before and after in vitro gastrointestinal digestion in present study. After digestion, contents of polyphenol, polysaccharide and their antioxidant activity, the inhibitory activity of alpha-amylase and alpha-glucosidase significantly increased. Punica granatum Linn and Actinidia globosa C. F. Liang displayed maximal increment up to 2, 0.25 and 1.6 fold in contents of polyphenols and polysaccharides, and the inhibitory activity of alpha-amylase, respectively. The correlation coefficient between contents and inhibitory activity of alpha-amylase increased in range of 0.002 to 0.485. Lycopersicon esculentum Mill and Pyrus bretschneideri Rehd exhibited maximum increase in the inhibitory activity of alpha-glucosidase with lowest contents of polyphenols and polysaccharides. The results indicated that polyphenols and polysaccharides digested synergistically contributing to the inhibitory alpha-amylase activity, and other responsibly bioactive ingredients for inhibitory alpha-glucosidase activity would be worthy discussed future. The findings above highlighted some potential application of common fruit juices in controlling hyperglycemia and obesity.