pH-responsive PVA/konjac glucomannan/functional liposome terpolymer composites: Spotlight on its structure-performance, functionality, barrier properties, controlled-release behavior, biodegradability, and its intelligent preservation role for food

To reduce petroleum-based feedstocks and develop multifunctional composite plastics, this study constructed pH-responsive γ-polyglutamic acid (γ-PGA) modified liposomes loaded with Alpinia galanga essential oil (Lip-PEO) and doped it into the esterified konjac glucomannan (KGM) - polyvinyl alcohol (PVA) network for ternary composite plastics. The results of scanning electron microscopy (SEM) and atomic force microscopy (AFM) show that the surface and cross-sectional structure of the composite plastic exhibits a smooth and flat morphology. This good compatibility resulted from the interactions between the components. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometry (XRD) verified the existence of hydrogen bonding forces between the components, and the three components' interactions further improved the co-polymer crystal structure. Notably, plastics' best compatibility was achieved with the P25K75 (PVA:KGM=75:25 v/v) ratio, which presents excellent thermal and light transmittance, barrier, and mechanical properties. Moreover, plastic degradability was improved by reducing the PVA ratio and introducing KGM, whereas Lip-PEO addition imparts pH-responsive behavior to plastics. Citrus packaging tests indicate that this packaging can effectively maintain fruit quality and extend shelf life. Furthermore, the plastic provides ideal storage stability. The results provide insights for the future green and intelligent food packaging design.