Valorization of cactus biomass to manufacture sustainable packaging films: moisture sorption behavior and influence of citric acid as crosslinking agent

Cactus mucilage-gelatin (CF/GTN)-based bio-composite film was fabricated via solution casting method. Citric acid (CA) as a crosslinking agent in a concentration of 0.5%, 1%, 3%, and 5% was used, and its influences on moisture sorption characteristics and mechanical properties of the film were studied. Sorption kinetics and sorption isotherm of developed films were obtained using Peleg and Guggenheim Anderson De-boer (GAB) model at 30 °C for 11.3%, 32.4%, 51.4%, and 75.7% relative humidity. Incorporating CA reduces the film’s moisture content, swelling ratio, water vapor permeability, and moisture sorption tendency. Equilibrium moisture content was lowest for 5% CA films for all humidity conditions. Guggenheim’s monolayer (c) and multilayer constant (k) decreases with an increasing degree of crosslinking. The regression coefficient (R) and the coefficient of determination (R) show the goodness of the GAB and Peleg models. The film with 0.5% CA has better crystallinity and the highest tensile strength among all the films, depicting its suitability for food packaging applications.