Starch granule sizes and degradation in sweet potatoes during storage

Abstract

Starch granule sizes can greatly influence the quality of both table and processed products of sweet potato (Ipomoea batatas (L.) Lam), an important food, feed and industrial crop. Sweet potatoes require storage under suitable temperatures for year around supply, but there is very little research on starch granule size variation during storage. We characterized dry matter content (DMC), starch content, soluble carbohydrate (SoluCarb), and starch granule length before and after storage at 13 °C for 60 d in the cultivars, SP3388, SP3391, ‘Beauregard’, and ‘Covington’. Tuberous roots with higher DMC tended to have greater DMC, starch content, SoluCarb, and starch granule length after storage. Starch granule sizes ranged nearly continuously from small to large, without frequency peaks of small granules or large granules. Smaller starch granules degraded faster than larger ones during storage. The findings provided insights into starch degradation in plants, can help predict the processing quality of sweet potatoes during storage, and may also assist in their dry matter and starch-related breeding.