Sweet potato ( Ipomoea batatas L.) exhibits diverse root flesh colors, and the overall quality of starch-based products largely depends on the physicochemical and structural features of the starches extracted from these roots. Although northern China represents a major sweet potato-growing region, the starch properties of differently colored root tubers from its main cultivated cultivars remain insufficiently characterized. Thus, 12 representative cultivars in this region, three each with white, yellow, orange, and purple roots, were used in this study. The starches isolated from these cultivars were systematically compared, and Pearson correlation and hierarchical cluster analyses were also performed based on starch parameters. White-fleshed cultivars exhibited the highest total starch content and amylopectin (AP) levels. Their average dry matter yield was also the highest reaching 16652.9 kg ha −1 . They showed larger mean granule diameters and the lowest proportion of B3 chains, with a reduction from 9.27% to 37.81%. Purple cultivars displayed the smallest average granule size, the highest peak temperature, onset temperature, conclusion temperature, and an increase in the average chain length of AP by 4.63–10.82%. Orange cultivars exhibited the highest peak viscosity (PV) and breakdown viscosity (BV), but the lowest setback viscosity (SV), whereas purple cultivars showed the opposite trend. Yellow and white cultivars displayed intermediate PV, BV, and SV values. No obvious differences were observed in hot paste viscosity and cold paste viscosity among orange, yellow and white cultivars. Overall, the starches from sweet potatoes with different root colors varied mainly in starch composition, AP chain-length distribution, granule size and certain viscosity characteristics, suggesting their potential for differentiated applications in food processing. Cluster analysis further indicated that cultivars with purple or white root colors shared comparable starch property profiles. These findings provide valuable insights into the relationship between root color and starch physicochemical behavior in sweet potatoes. • White cultivars showed the highest AP content and lower proportions of long AP chains. • Purple cultivars exhibited the lowest A1 chain proportion, granule size, PV, and BV. • Orange and yellow cultivars showed medium granule size and long AP chain proportions. • Orange cultivars displaying the highest PV and the lowest SV. • Cultivars with purple or white root colors shared comparable starch property profiles.
Duan et al. (2026) studied this question.