Exploring the post-harvest storage losses of phytonutrients in different aggregatum onion varieties of Tamil Nadu

Post-storage deterioration of aggregatum onion under ambient conditions was investigated. Two indigenous [Perambalur local (PL) and Manachanallur Local (ML)] and two TNAU released varieties [Co (On) 5 & Co (On) 6] were taken up for this study. Determination of phenol, flavonoid, pyruvic acid, ascorbic acid and non-structural carbohydrates was carried out with an emphasis on different storage periods viz., 0th, 30th, 45th, and 60th days. As storage duration increased, the overall phenol content decreased. The mean total phenol concentration in PL was high (71.27 ± 0.64 mg GAE 100g-1 FW) on 60th day. The flavonoid concentration increased as the storage duration increased (0th to 60th day). The highest mean total flavonoid concentration was found in PL (69.07 ± 1.87 mg QE 100g-1 FW). The pyruvic acid content decreased with storage time, and the mean pyruvic acid content on the 60th day of storage was greater in PL 2.79±0.05 mole g-1 FW. The ascorbic acid content was reduced as storage time increased. The Co (On) 6 has the highest ascorbic acid 8.52±0.28 mg 100 g-1FW. As storage days varied, a fluctuating sugar profile pattern was seen among various onion cultivars. When germination first began, the concentrations of glucose and fructose increased while sucrose decreased. Thus, post-harvest storage studies confirm the nutrient loss during storage and the variety PL was regarded as one of the best cultivars that can withstand post-harvest nutrient loss than the other varieties.