Abstract: This article took sweetpotato cultivar Xinxiang as the test material, which were sampled every 7 days after 70 days of planting at 70, 77, 84, 91, 98, 105, 112, and 119 days. The dry matter content, starch content, soluble sugar content, amylase activity, polyphenol content, oil content of sweetpotato chips, water absorption value and iodine value of the whole powder were measured, and the change rules and correlations of each index were analyzed. The results showed that starch content was increasing in different growth stages, and the trend of the dry matter content was similar to that of starch content. Soluble sugar content showed a slow downward trend. At the same time, there was a significant positive correlation between the number of days of growth stages and water absorption value and iodine value of the whole powder, and positively correlated with the oil content of sweetpotato chips. There was a significantly positive correlation between the dry matter content and water absorption value of the whole powder, and soluble sugar content was negatively correlated with iodine value of the whole powder. Therefore, in the growth stages of 77-84 days, the dry matter content was 24.17%, oil content was 23.30%, polyphenol content was low and suitable for sweetpotato chips processing; in the growth stages of 119 days, it was suitable for starch processing with the highest starch rate; in the growth stages of 84 days, it was suitable for roasting and cooking with the highest soluble sugar content.

Key words: sweetpotato, growth stages, nutritional components, processing characteristics