Plant protein-based active films via heteroprotein phase separation

In recent years, with the aggravation of plastic pollution and the enhancement of people's awareness of environmental protection, biodegradable active films have attracted wide attention. Based on the phase separation behavior of plant protein, active films with excellent mechanical properties and barrier properties can be tailored. In this study, a new type of zein/soybean protein isolate (SPI) active film via heteroprotein phase separation was prepared. We have innovatively transformed SPI self-supporting gels into highly lubricating microgels to prepare the film matrix, and filled it with zein nanoparticles and zein coacervate, respectively. Hydrophilic SPI and hydrophobic zein were used to achieve the co-encapsulation of Epigallocatechin-3-gallate (EGCG) and α-tocopherol. The composite films showed different phase separation modes, morphology and microstructure after solvent evaporation. The mechanical properties of the composite films containing different zein fillers were improved, meanwhile, the permeability of water vapor and oxygen was significantly reduced. The composite films with excellent antibacterial and antioxidant properties slowed down the oxidation of fresh-cut apples. This study offers a novel approach for advancing the development of plant protein-based active films.