Alpha Amylase Activity and Sprouting During Short Term Storage of Taro Corms

Authors
A. T. Modi
R. Mare
School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa.
Abstract
The objective of this study was to investigate taro [Colocasia esculenta (L.) Schott] corm quality as determined by changes in starch morphology and degradation during storage after harvest. Starch is the major nutrient component of taro corms and its quality in corms that are stored as planting material or consumption has not been fully explained. Scanning electron microscopy was used to examine the changes that occur to the surface morphology of starch granules in corms of taro landraces, Dumbe-dumbe, Mgingqeni and Pitshi, stored at cool (12ºC) and ambient (20ºC) temperatures. Alpha-amylase activity and sprouting were used as indicators of changes in the starch granules, and hence corm quality, during storage in polyethylene bags, card boxes, and mesh bags. The degradation of starch granules, alpha amylase activity, and sprouting increased over storage time and varied with landraces, storage material, and temperature. Overall, there was 23% more alpha-amylase activity and 67% more sprouting at 20ºC compared with 12ºC. With respect to storage material, polyethylene bags showed the highest alpha-amylase activity (0.18 EU 0.1 g-1) followed by card boxes (0.15 EU mg-1 0.1 g-1) and mesh bags (0.14 EU mg-1 0.1 g-1). A similar, but more pronounced, trend was observed for sprouting. The findings have implications for selection of storage material for food and propagule storage.

Keywords

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Journal of Agricultural Science and Technology
Volume 18, Issue 4
July and August 2016
Pages 1053-1063