A novel approach to prepare protein-proanthocyanidins nano-complexes by the reversible assembly of ferritin cage

The application of proanthocyanidins (PCs) in food industry is limited because of its instability and vulnerability against oxidative damage. In this work, by taking advantage of the reversible assembly characteristic of ferritin, apo-red bean ferritin (apoRBF)-PCs composites (FPs) were designed, and results showed a ratio of 1/10 of PCs (PCs/apoRBF, w/w) were encapsulated into a ferritin cage, and the encapsulation ratio was 23.8%. The FPs exhibited a homogeneous form, and maintained a spherical morphology. Further more, the thermal and light stability of PCs in FPs was significantly increased compared to free PCs (p < 0.05). The in vitro digestion indicated that apoRBF could prolong the release of PCs in simulated gastrointestinal tract. Additionally, the antioxidant activity of FPs was partly retained (56.6%) as compared to free PCs. This work offers a novel method to encapsulate and stabilize polyphenols and might be favorable for the application of ferritin in food industry.