Sustainable sweetpotato peel-based nanocoatings reinforced with sodium alginate: enhancing shelf life and reducing postharvest losses in agricultural produce.

Postharvest losses of agricultural products present a considerable negative impact on food security and economic stability, necessitating sustainable preservation solutions. The effectiveness of edible nanocoatings derived from sweetpotato (SP)-peel nanomaterial (sNM) as a novel approach to prolonging the shelf life of several sweet/red-potato cultivars was examined in this work. The nanocoating formulations were prepared using two concentrations of sodium alginate (SA,1 and 2 wt%), both with and without calcium chloride as crosslinking agent. These formulations were then assessed for their effects on the postharvest quality of selected potato roots during storage. Rheological analysis of the sNM-SA formulations demonstrated that crosslinked coatings had markedly increased viscosity and gel strength, forming a stable semi-permeable barrier that effectively controlled moisture loss and gas exchange. The uncoated potato roots demonstrated the greater weight losses, reaching 3.5 % for Beauregard SP, 6.5 % for Bonita SP and 3.5 % for red potatoes, by the end of the 30-day storage duration. The crosslinked coatings significantly reduced weight losses, below 2.0 % for Beauregard SP, 4.0 % for Bonita SP, and 1.5 % for red potatoes. The respiration rates were higher in the uncoated samples, reaching 18-20 mL CO₂/kg·h in sweetpotatoes and 7 mL CO₂/kg·h in red potatoes. The crosslinked formulations showed the most significant impact on decreasing respiration rates, sustaining CO₂ levels below 12 mL CO₂/kg·h for Beauregard SP, 13 mL CO₂/kg·h for Bonita SP, and 5 mL CO₂/kg·h for red potatoes. The results indicate that the crosslinked sNM-SA coatings improve postharvest quality, diminish metabolic activity, and prolong the shelf life of root vegetables, presenting a viable biodegradable and sustainable option for food preservation.