Aloe vera-mediated ZnO NP-reinforced polysaccharide nanocomposite dispersions for postharvest preservation of kiwifruit.

This paper deals with the drawbacks of the single-component edible coatings through the development of an effective multi component nanocomposite dispersion system for postharvest preservation. A biodegradable edible coating made of carboxymethyl cellulose (CMC), guar gum (GG), and carrageenan (CGN) was developed and fortified with zinc oxide nanoparticles (ZnO NPs) green-synthesized by using Aloe vera extract. This aimed at designing a stable bioactive coating that can inhibit postharvest and microbial spoilage of kiwi fruit. The hydrodynamic diameter was less than 150 nm, the polydispersity index values were below 0.30, and the zeta potential values were negative (up to -27.1 mV). The antibacterial properties have a maximum diameter of inhibition of Escherichia coli, ranging up to 18.3 mm, and Staphylococcus aureus, ranging up to 17.6 mm. Under storage conditions of approximately 25 °C and 90 to 95% relative humidity, the optimized formulation (CGC-Z2) enhanced the quality more than the uncoated controls. The percentage of weight loss lowered to about 10-12% vs 18-20% in the control, firmness improved (2.0 kg cm-2 vs 0.2 kg cm-2), and the percentage of decay was 15.4% vs 64.5% in uncoated fruit. Coated fruit experienced greater retention of TSS and more stable pH, moderate rises in total soluble solids, colour retention, and increased sensory acceptability scores (8/9) vs control (4/9). In general, the results indicate that coatings are a viable, biodegradable, and green method of increasing the shelf life as well as preserving the quality of kiwi fruit during storage.