Metal-polyphenol networks hardened coacervate microcapsules for encapsulation of piperine: Crosslinking mechanism, stability, and in vitro digestion

Although metal polyphenol networks (MPNs) have been widely investigated in the field of multifunctional surface modification, the exploration of their application in the hardening of microcapsules is relatively scarce. In this study, piperine (PIP)-loaded microcapsules were hardened and modified using MPNs formed by tannic acid (TA) and Fe 3+ (TA-Fe 3+ ) to enhance the stability of the microcapsules and the bioaccessibility of PIP. The results showed that TA-Fe 3+ constructed a network-modified coating with a supramolecular structure on the surface of microcapsules. The TA-Fe 3+ -hardened microcapsules exhibited excellent environmental stability and illustrious encapsulation efficiency (97.7 %). In vitro digestion demonstrated that TA-Fe 3+ delayed the release of PIP in the gastrointestinal tract and improved the bioavailability of the microcapsules. This research established a vital basis for the creation of novel microcapsule systems based on MPNs and demonstrated the potential for applications in food science for the delivery and controlled release of bioactive ingredients.