Improving the active food packaging function of poly(lactic acid) film coated by poly(vinyl alcohol) based on proanthocyanidin functionalized layered clay
Chengyu Wang, Long Mao, Jin Yao, Heping Zhu
Abstract
In this paper, natural plant polyphenol-proanthocyanidin (PAC) and layered clay-layered double hydroxides (LDHs) were firstly introduced into poly(vinyl alcohol) (PVA) based coatings to construct PAC/PVA and PAC functionalized LDHs ([email protected])/PVA dual active coatings, and further successively coated on the surface of PLA base films to develop PLA active films. The results showed that PAC and copper ions were successfully loading on the LDHs surface through adsorption and complexation. After a certain amount (≥3 wt%) of [email protected] was added, active packaging functions and gas barrier properties of PLA active films were improved markedly. When 5 wt% [email protected] was added, antioxidant and antibacterial properties of PLA active films reached 84.31% and 95.5%, oxygen and water vapor transmission rate decreased by 99.4% and 62.6% compared with PLA base film, and the shelf life of pasteurized milk was extended from 60 h to 96 h. Active substances release test indicated that [email protected] could not only delay the release of active substances in the early stage, but also supplement the release of active substances in the later stage, thus extending the shelf life of food more effectively. Therefore, PLA active films have good application potential in the field of active food packaging.