From mustard (Brassica juncea) to packaging: anthocyanin chromism and glucosinolate co-additives yield UV-shielding, antioxidant, and freshness-indicating films.

This study aimed to develop a bio-based intelligent packaging film using mustard (Brassica juncea) as a single-crop resource, integrating leaf-derived anthocyanins as pH-responsive indicators and seed-derived glucosinolate-rich extracts as multifunctional additives in an alginate-starch matrix. Glucosinolate incorporation enhanced ultraviolet shielding, antioxidant activity, and intermolecular interactions, resulting in improved barrier and mechanical properties. Among the formulations, the film containing 6 wt% glucosinolates exhibited optimal performance, achieving a tensile strength of 15.47 MPa, elongation at break of 29.09%, and reduced water-vapor and oxygen permeability. This optimized film effectively delayed increases in pH, total volatile basic nitrogen, and microbial growth in chilled salmon. Moreover, film color variation displayed strong correlations with freshness indicators, enabling visual monitoring and extending shelf life to 6 days. These findings show that mustard-derived anthocyanin-glucosinolate films provide a sustainable strategy for intelligent packaging with simultaneous freshness indication and preservation functions.