Evaluation of a Low cost Storage System for Shelf-life Extension of Fresh Onions. Nigerian Journal of Post-Harvest Research, 3(4), 1-10

Onions, a major commercial vegetable crop, suffer losses during off-season storage due to sprouting and weight loss. This study examined the impact of different storage systems on the storability of onion bulbs under three storage conditions: a conventional onion storage system (COSS), the Nigerian Stored Products Research Institute's (NSPRI) solar storage system (NSCSS), and a low-cost onion storage system (LCOSS). 2,500 kg of fresh red onions were procured, sorted, and stored for a period of six months, between March and September. Samples were taken randomly every month to analyse their physical and chemical changes. Descriptive statistics and ANOVA were performed on the data recorded using SPSS at a significant difference of (p<0.05). It was observed that when relative humidity increases, particularly over 50%, there is a corresponding rise in the percentage weight loss of the stored onion. An average weight loss of 73.3%, 71.2%, and 85.6% was recorded at the end of the experiment for LCOSS, NSCSS, and COSS, respectively. A significant increase (p<0.05) in total polyphenols from 5.50 ± 0.55 GAE (mg/g) in all storage systems was observed during the study, with a steady increase (approximately 28.9%) in OSS, which is 37.7% higher than in other systems at the end of storage time. However, ascorbic acid declined significantly, with less than 50% retained beyond the third month. The dietary energy value decreased significantly (p<0.05) by 62.2%, 22.7%, and 32.8% in NSCSS, LCOSS, and Conventional, respectively. The study showed that LCOSS reduced sprouting. However, there is a need to modify both NSCSS and LCOSS to minimise weight loss.