Enhanced performance of an eco-friendly and sustainable secalin-corn starch packaging film via citric acid cross-linking

Growing concerns over plastic pollution have intensified the search for sustainable food packaging solutions. This study introduces a novel biodegradable film based on secalin (SCL) protein from rye, a rarely explored biopolymer, blended with corn starch (CS) and cross-linked with citric acid (CA). Films were prepared at different SCL/CS ratios (1:2, 1:1, 2:1) and CA concentrations (0 %, 2 %, 5 %, 10 %) and comprehensively characterized. Field emission-scanning electron microscopy (FE-SEM) and thickness analysis confirmed that CA enhanced phase compatibility, while barrier tests revealed improved water vapor and oxygen resistance through CA-induced tortuous diffusion paths. The optimized 2:1 SCL/CS film with 2 % CA exhibited balanced mechanical strength, barrier performance, and strong antioxidant/antimicrobial activities, attributed to metal ion chelation and bacterial membrane disruption. Unlike conventional biodegradable films, this formulation was successfully applied as active packaging for mushrooms, showing improved preservation by reducing weight loss and visual spoilage under ambient conditions. These findings highlight the timely potential of SCL-based composites as multifunctional, eco-friendly packaging materials for perishable foods.