Fabrication and characterization of fish oil emulsions stabilized by metal-phenolic network coatings-decorated Acipenser sturgeon protein

Acipenser sturio fish oil, rich in omega-3 PUFAs, offers potential for functional foods but is prone to oxidative degradation. This study investigates enhancing antioxidant and emulsifying properties of the oil by modifying Acipenser sturgeon protein (ASP) using metal-phenolic networks (MPNs). ASP was coated with EGCG (epigallocatechin-3-gallate) and Ca2+, forming ASP-EGCG-Ca complexes (AECas) used as emulsifiers. The study examined the influence of interface compositions on the physicochemical and oxidative stability of AECas emulsions. Results showed AECas altered protein conformation, increased particle size and zeta potential, and improved antioxidant activity. Fish oil emulsions stabilized by AECas demonstrated superior stability under neutral pH compared to pH-adjusted ASP emulsions. Notably, AECa4 reduced primary oxidation products by 75.14 % and secondary ones by 83.18 %. This research highlights the use of MPNs for encapsulating ASP as an effective antioxidant and emulsifier to protect lipid-rich emulsions from oxidation.