UV-blocking biodegradable film based on flaxseed mucilage/pectin impregnated with titanium dioxide and calcium chloride for food packaging applications

A UV blocking and potentially biodegradable composite films are fabricated from flax seed mucilage and pectin with different concentrations of titanium dioxide (TiO2) and crosslinked with calcium chloride (CaCl2). This study aimed to evaluate the physical, surface, and optical properties including color, potential biodegradability, and absorption kinetics of the developed film. From the observations made, addition of 5 wt% TiO2 enhanced UV barrier property with a total color change (Delta E) of 23.441 +/- 0.54 and increased its crystallinity to 54.1 % from 43.6 %. Crosslinking agent and TiO2 resulted in a prolonged period of biodegradation of >21 days when compared to neat film. Also, swelling index of crosslinked film was reduced by 3 times of non-crosslinked films. Surface of the developed films has no cracks and agglomerates as observed from scanning electron microscope. Moisture absorption kinetic study reveals that all the films have best-fit data following a pseudo-second-order kinetic model with a correlation coefficient >= 0.99 and the rate was controlled by inter-particle diffusion. The film with 1 wt% TiO2 and 5 wt% CaCl2 showed the lowest rate constants (k1) of 0.27 and (k2) of 0.029. The results suggest that this film can be potentially used in food packaging as a UV-blocking layer with potential biodegradability and good moisture resistance as compared to pure flax seed mucilage or pectin films.