Vanillin reinforced cationic starch/poly(vinyl alcohol) based antimicrobial and antioxidant bioactive films: sustainable food packaging materials†

Abstract

The growing demand for eco-friendly and sustainable packaging solutions has accelerated the development of biodegradable materials for fresh food preservation. In this study, bioactive films were developed using cationic starch (CT) and poly(vinyl alcohol) (PVA), functionalized with varying concentrations of vanillin (VN) via a solvent casting method. The resulting CT/PVA/VN (CPVN) films were systematically characterized to evaluate their functional properties. Notably, films with 3 wt% VN exhibited excellent UV-blocking ability and a remarkable enhancement in tensile strength (∼49.44%) compared to the pristine CT/PVA blend. The incorporation of VN also significantly improved the barrier properties of the films, reducing water vapor permeability (∼60.01%) and moisture adsorption (∼30.54%). Furthermore, the phenolic structure of VN contributed to a substantial increase in antioxidant activity (∼81.33%) and imparted potent antimicrobial activity against foodborne pathogens such as Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans. The CPVN films also demonstrated promising environmental compatibility, achieving over 40% biodegradation in soil within 30 days. These findings highlight VN's multifunctional role in enhancing the structural, barrier, and bioactive properties of CT/PVA films, making CPVN films strong candidates for sustainable food packaging applications.