Physiological Changes in Red Onion Bulbs at Different Storage Temperature

Abstract

Onion bulbs were stored at five different temperatures to know the storage behavior of onion bulbs. Indian red onion bulbs were kept without wrapping at ambient conditions (25˚C ± 3˚C and 75% RH) and within polyethylene pouch at 2.5˚C, 6˚C, 7˚C and 13˚C for 60 days of storage period. Weight loss, total soluble solids (TSS), number of sprouted and rotten bulbs were measured at an interval of 10 days throughout storage. The greatest decrease (23.25%) in weight was observed throughout storage for onions stored at ambient conditions. TSS was observed to increase in all samples until 40 days of storage and then decreased up to 60 days. Lowest TSS (14.89˚Bx89˚Bx) was found in onion stored at ambient conditions at the end of storage. Maximum sprouted (67.25%) and rotten (17.78%) onions were observed for onions stored at 13˚C, whereas minimum sprouted and rotten onions were found at 2.5˚C at 60 days of storage. Results also recommend lowest temperatures (2.5˚C-6˚C) for prolong storage life of onion with no detrimental effects.