EFFECT OF ZINC OXIDE AND SULPHUR NANOPARTICLES ON STORAGE INTEGRITY AND QUALITY TRAITS OF STORED ALLIUM CEPA L UNDER CONTROLLED ENVIRONMENT CONDITIONS

Abstract

Onion (Allium cepa L.) is one of the most important vegetable crops grown across India, and yet, every year a large share of the harvest is lost during storage. Sprouting, rotting, weight loss, and quality drop are the most common problems, and traditional chemical sprout suppressants are slowly losing favour because of residue concerns. This study, carried out under the discipline of Olericulture (Vegetable Science), explored whether nanoparticles of zinc oxide (ZnO) and sulphur (S), applied as a post-harvest dip, can help keep stored onion bulbs in better shape for a longer time under controlled storage conditions. Freshly cured bulbs of the Nasik Red variety were treated with three concentrations of ZnO (50, 100, 150 ppm), three concentrations of sulphur nanoparticles (100, 200, 300 ppm), a combined treatment of ZnO 100 ppm and sulphur 200 ppm, and an untreated control. The bulbs were stored at 25 ± 2 °C and 65 ± 5% relative humidity for 120 days, with observations recorded every 30 days. Parameters studied included physiological loss in weight, sprouting and rotting percentage, total soluble solids, ascorbic acid content, and pyruvic acid content. The results showed that the combination treatment performed the best, cutting weight loss by nearly 41% and sprouting by close to 58% compared to the control. Quality traits like vitamin C and pungency were also better retained. The study suggests that ZnO and sulphur nanoparticles, especially when used together at moderate doses, can serve as a safer and effective alternative for extending onion shelf life in vegetable post-harvest management.