Zein coacervate as a new coating material for temperature-triggered microcapsule and fruit preservation

Due to the opposite effect of hydrophilicity and hydrophobicity, the formation of a hydrophobic shell on the surface of hydrophilic cores in aqueous environments is a challenge. Zein coacervate originating from plant protein liquidliquid phase separation has low interfacial energy, which creates conditions to achieve the above goals. This work proposed zein coacervate as a new coating material for the preparation of hydrophilic-hydrophobic core-shell microcapsules or the coating of fruit. Different from particles simply stacking at the interface, this zein coacervate coated on the surface could form a denser shell. For the prepared microcapsules, this dense zein coacervate shell could prevent the release of ascorbic acid at a low temperature, while the dense shell could be destroyed to have a quick release at approximately 37 ℃, creating a kind of hydrophilic-hydrophobic core-shell microcapsule with temperature-dependent triggered performance. This dense shell could also endow microcapsules with anti-ultraviolet and antioxidant capacities, features that microcapsules without this dense shell are lacking. For the coating of fruits, this dense shell derived from plants could come in contact with food products and be beneficial for the preservation of fruits. Therefore, this zein coacervate could have the potential to be a healthy and green coating material for a broad range of applications, such as cosmetics, food, drug delivery and the preservation of fruits and vegetables.