Protein-polysaccharides based nanoparticles for loading with Malus baccata polyphenols and their digestibility in vitro

The poor solubility, instability and low absorption rate obstruct the bioavailability of polyphenols isolated from Malus baccata (MBP) during gastrointestinal digestion. In order to solve the limitable problems, the food-grade nanoparticles were fabricated by mucin (MC) and Hohenbuehelia serotina polysaccharides (HSP) for delivery of MBP (MBP-NPs). The physicochemical properties and morphology of MBP-NPs prepared by different condition were respectively characterized. During gastrointestinal digestion in vitro, the release characteristic and variation in phenolic composition of MBP-NPs were evaluated. The results showed that MBP-NPs formed by hydrogen bonding and hydrophobic interaction possessed the regularly spherical shapes and smooth surfaces and semi-crystalline properties. Moreover, MBP-NPs presented the excellent physicochemical stability. During simulated gastrointestinal digestion in vitro, MBP-NPs exhibited the sustained release characteristics of phenolic compounds, which were confirmed by SDS-PAGE measurement. Compared with that of unencapsulated MBP, the significant variation was occurred in the phenolic composition of MBP-NPs, indicating that MBP-NPs could prevent the degradation and transformation of phenolic compounds. This study provides a novel strategy to improve the bioavailability of polyphenols.