Effect of recharging and packaging on moisture loss and quality change in sweet potato during short term storage
This study was carried out to determine the effect of recharging and packaging on the shelf life of sweet potato roots during short-term storage. Freshly harvested potatoes from five genotypes were recharged by immersing in tap water for 0, 7 and 14 hours and thereafter evaluated for weight gain or loss, relative solute leakage, total soluble solids and dry matter content for 18 days. Recharging led to significant weight gain, decreased weight loss and decrease in relative solute leakage in all the genotypes. However, recharging did not have significant effects on total soluble solids at the end of storage. Significant linear and/or quadratic effects on recharging duration treaments were observed in weight gain, weight loss, relative solute leakage and total soluble solids. The beneficial effect of recharging sweet potato was, therefore, due to replacement of lost moisture and decrease in moisture loss during storage following recharging. Recharging for 14h would be adequate to gain sufficient extension of shelf-life of sweet potato roots. The effect of packaging on moisture loss and nutrient quality of two genotypes of sweet potato was also determined. Each of two genotypes, 'KEMB 10' and 'Yanshu" were recharged for 14 hours and packaged in kraft paper bag, perforated polythene bag and nylon gunny sack. The packaged potatoes were then stored at ambient conditions, with roots placed on an open plate as controls. During storage the potatoes were analysed for weight change, loss in reduced ascorbic acid, beta-carotene contents, total sugars and total soluble solids. Packaging significantly decreased weight loss as well as reduced ascorbic acid and increased nutrient retention. Perforated polythene bag-packaged sweet potato roots exhibited the highest decrease in these losses compared to the roots in other packages and in no package (control). Beta-carotene and total sugars increased during storage, with perforated polythene bag-packaged sweet potato roots having the highest values. However, packaging had no significant effects on total soluble soild content of the roots. Results of these studies show that recharging as well as packaging can be employed to improve the shelf-life of sweet potato. Recharging for 14h and packaging in perforated polythene bags can be recommended as the best combination of treatments to be applied in attempting to extend the shelf-life of sweet potato.