Higher affinity of polyphenol to zein than to amyloid fibrils leading to nanoparticle-embed network wall scaffold to construct amyloid fibril-zein-EGCG hydrogels for coating of beef

Globally, 800 million are undernourished and 2 billion are deficient in micronutrients. A regular dietary intake of meat is one of effective strategies to fight against undernourishment and deficiency of micronutrients. However, meat is a typical perishable food; proper handling to extend the shelf life of meat is required. In the present study, homogenous hydrogels composed with high contents of lysozyme amyloid fibrils, zein and green tea polyphenol epigallocatechin gallate (EGCG) were developed via the orchestration of protein–protein interaction and polyphenol-protein interaction for coating of beef. The protein–protein interaction between amyloid fibrils and zein showed higher affinity than that of the polyphenol-protein interactions. In addition, polyphenol EGCG was found to be more inclined to bind with zein than to the amyloid fibrils. Thus, the amyloid fibrils performed as the scaffold, in which EGCG on one hand induced the zein aggregate nanoparticles and on the other hand deposited on the surface of amyloid fibrils, leading to the dense multi-pore network with the nanoparticle-embed wall. It served as the microstructure mechanism for the enhanced gel strength. Coating of fresh chilling beef with the amyloid fibril-zein-EGCG hybrid hydrogels effectively protected the freshness and tenderness through inhibiting the over-growth of microorganisms and oxidation of lipid. This study paves the way to develop functional edible biomaterials via polyphenol induced coordination of the protein–protein interaction and polyphenol-protein interaction, where polyphenol acts as the molecular glue. This strategy shows high application potentials in health promotion related fields, including edible coating to extend the shelf-life of fresh meat.