Preparation, structure and stability of protein-pterostilbene nanocomplexes coated by soybean polysaccharide and maltodextrin

Pterostilbene (PTS) has received considerable attention in recent years because of its beneficial effects on health; however, its poor solubility hinders its application in the food industry. This study aimed to prepare and characterise three types of proteins (whey protein isolate (WPI), soybean protein isolate (SPI), and flaxseed protein isolate (FPI)) conjugates of PTS, which could improve its solubility and stability. The results showed that the spherical particles of the protein-based nano-complexes were dissociated and homogenous. Proteins bound to PTS mainly through hydrophobic interactions and hydrogen bonding, and PTS in proteins existed in an amorphous state. FPI conferred PTS with better thermal stability than WPI and SPI. Further coating of FPI-PTS with soybean polysaccharide and maltodextrin yielded a more stable nanocomplex structure. The prepared nanocomplex powder exhibited better thermal, illumination, and storage stabilities than FPI-PTS. This study provides guidelines for the potential application of protein-based nano-complexes in functional foods. • Proteins has potentiality to develop into pterostilbene (PTS) vector. • Flaxseed protein (FPI) could provide a better protection to PTS during heating. • Hydrophobic interaction and hydrogen bonds are main forces for FPI-PTS formation. • A coating of soybean polysaccharide and maltdextrin improved stability of FPI-PTS.