Development of alginate-based edible coatings of optimized UV-barrier properties by response surface methodology for food packaging applications

Despite the outstanding characteristics of alginate, it suffers from bad UV-barrier, water barrier, and antimicrobial properties limiting its wide usage in food packaging. For this concern, Box-Behnken design (BBD) was applied to prepare an alginate-based edible coating of the best optimized UV-shielding properties upon the incorporation of both Aloe vera (AV) and zinc oxide nanoparticles (ZnO-NPs). The optimized minimum UV-transmittance was 4.96% when the optimized compositions of alginate (1.05 g), AV (2.95 g), and ZnO-NPs (4.93 wt%) were used. FTIR was used to verify the successful edible coating preparation while the wide-angle X-ray diffraction (XRD) was used to identify the interactions between the film's components. The incorporation of both AV and ZnO-NPs significantly improved alginate's thermal, water vapor permeability (WVP), mechanical and antimicrobial properties. In addition, the films incorporated with both AV and ZnO-NPs exhibited excellent UV-barrier properties compared with neat alginate. The optimized alginate film incorporated with both ZnO-NPs and AV significantly extended the shelf-life of tomato fruits up to 16 days without any defects. Due to the outstanding physical, UV-shielding, and antimicrobial properties of the optimized alginate/AV/ZnO-NPs film, it could be used potentially in food packaging industries.