Antibacterial properties of cassava starch/xanthan gum/zinc oxide nanoparticles coating solution and physicochemical analysis of coated banana (Musa acuminata) for shelf-life extension

Bananas serve as a nutrient-rich energy source for human diets, and a valuable raw material for downstream products. Despite the high demand for bananas, they have a relatively short shelf-life. To mitigate these shortcomings, researchers have explored the use of edible coatings to extend the shelf-life of bananas. Nevertheless, only a few studies have assessed the integration of starch, gum, and zinc oxide nanoparticles (ZnONPs) in developing a coating solution that can preserve the qualities of bananas post-harvest. Therefore, the present work assessed the antibacterial properties of a novel edible coating formulation combining cassava starch, xanthan gum, and ZnONPs, and its impact on the physicochemical characteristics and shelf-life of bananas of the ‘Pisang Berangan’ variety (Musa acuminata). Firstly, coating solutions with compositions of cassava starch, xanthan gum, and varying concentrations of ZnONPs were prepared. Their antibacterial properties were then assessed using the disc diffusion method. Subsequently, pisang berangan were coated with the prepared coating solutions via the dip-coating method. Finally, the shelf-life study was performed to evaluate the effects of the coating solution on the physicochemical characteristics and shelf-life of coated pisang berangan. Based on the results, the coating formulation containing 0.5% ZnONPs exhibited the most potent antibacterial properties. Remarkably, coated pisang berangan recorded an extended shelf-life, lasting up to 15 days compared to only nine days for uncoated pisang berangan. Furthermore, coated pisang berangan demonstrated significantly lower weight loss and significantly higher total soluble solids (TSS), pH level, titratable acidity (TA), and firmness than uncoated pisang berangan. The synergistic effect was contributed by the combined protective role of cassava starch, the enhanced coating adhesion of xanthan gum, and the antimicrobial properties of ZnONPs. In summary, the formulated cassava starch/xanthan gum/ZnONPs edible coating solution (1.0%:0.5%:0.5% ratio) yielded the longest shelf-life of pisang berangan. The findings of the present work would boost the economic value of bananas, especially pisang berangan.