Performance of some purple-fleshed Sweet Potatoes (Ipomoea batatas L.) as influenced by different storage conditions

Abstract

Sweet potatoes are becoming a research focus in recent years due to their unique nutritional and functional properties. Purple sweet potato is a special type having high anthocyanin pigment and phenol content in the root. Sweet potato physiological parameters and biochemical constituents were evaluated to study the comparative performance in five cultivars (X-9, TSP-12-10, Cross 4, Sree Kanaka and Kishan) at harvest and after storage for 30 days under ambient, cool and refrigerated storage condition. All cultivars in different storage conditions exhibited steady weight loss and sprouting from the beginning and the tubers kept in refrigerated storage significantly least PLW%, followed by cool storage and ambient storage. Results of different storage conditions indicated that, there was a downward trend in starch, ascorbic acid and anthocyanin content with the increasing of storage time while total sugars and phenol contents gradually increased. Sugar content of the tubers tended to increase due to hydrolysis of starch which is responsible to enhance sprouting. Increase of total sugar content and retention of anthocyanin was highest in refrigerated storage followed by cool and ambient storage. After 4 weeks exposure to 50C, the rate of increase of phenolic content of sweet potato tubers was significantly higher whereas loss of ascorbic acid was minimum than tubers stored in cool (200C) and ambient condition (30-350C). The highest starch, ascorbic acid and antioxidant property viz., anthocyanin and total phenol were obtained from Cross-4 which also attained a promising performance in morphological characteristics. So it is identified to be superior considering all qualitative aspects which can be selected for further improvement and can be promoted for cultivation.