Facile and green synthesis of nanocarriers from chondroitin sulfate-based and whey protein isolate with improved stability and biocompatibility for anthocyanins protection

Anthocyanins (ACNs) are widely used in the culinary, cosmetic, and biomedical industries owing to their potent bioactivities. However, the rapid degradation of ACNs in extreme environments is a major limiting factor for their physicochemical stability and bioactivity. This study reported a facile and environmental-friendly ACN embedding strategy using chondroitin sulfate (CS) and whey protein isolate (WPI) to prepare the CS/WPI@ACN complex. The encapsulation efficiency of CS/WPI@ACN reached up to 84.87 % when the CS-to-WPI mass ratio was 1:5, and the core-to-wall material ratio was 1:3. Molecular docking analysis revealed that the CS/WPI complex harbored a concave chamber, which was conducive for the embedding of small ACN molecules and promoting drug activity. The CS/WPI@ACN complex enabled sustained ACN release in the gastrointestinal tract in vitro. The CS/WPI@ACN complex was stable under ascorbic acid treatment conditions, high temperatures, and a wide range of pH levels. In vitro release data demonstrated that most encapsulated ACNs were released in the small intestine. Furthermore, the antioxidant activity of the CS/WPI@ACN complex was higher than that of free ACN. Therefore, this study proposed a strategy to protect unstable active substances, and laid a foundation for blueberry anthocyanins in the high-value utilization of functional drinks.