Development of Chitosan–Whey Protein Edible Films with Lemon Essential Oil for Oil Packaging

This study focuses on the development and characterization of biodegradable edible films for edible oil packaging as an alternative to conventional petroleum-based plastics. Composite films were prepared using chitosan, whey protein isolate (WPI), and lemon essential oil (LEO), with cassava starch, glycerol, and Tween 80 incorporated to improve film-forming and functional properties. The study was designed to (i) determine the optimal chitosan concentration for achieving desirable mechanical strength, solubility, and oil barrier performance, (ii) evaluate the effect of WPI incorporation on overall film properties, and (iii) investigate the role of LEO in enhancing antioxidant and antimicrobial activities. The results indicate that film characteristics were strongly influenced by formulation composition, with noticeable synergistic effects among the components. The optimized formulation, consisting of 2% (w/v) chitosan, 2% (w/v) WPI, and 5% (v/v) LEO, produced films with a thickness of 0.07 mm, tensile strength of 1.04 ± 0.05 N, and adhesiveness of 0.12 ± 0.03 N. In addition, the films demonstrated significant antimicrobial activity against Salmonella enterica, high antioxidant capacity (71.11 ± 1.11%), and effective oil barrier properties. These findings suggest that the developed composite films have strong potential as multifunctional, biodegradable packaging materials suitable for lipid-rich food applications, contributing to more sustainable and safe food packaging solutions.