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

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 (۱۲ºC) and ambient (۲۰ºC) 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 ۲۳% more alpha-amylase activity and ۶۷% more sprouting at ۲۰ºC compared with ۱۲ºC. With respect to storage material, polyethylene bags showed the highest alpha-amylase activity (۰.۱۸ EU ۰.۱ g-۱) followed by card boxes (۰.۱۵ EU mg-۱ ۰.۱ g-۱) and mesh bags (۰.۱۴ EU mg-۱ ۰.۱ g-۱). A similar, but more pronounced, trend was observed for sprouting. The findings have implications for selection of storage material for food and propagule storage.