Comparative analysis of phytochemicals and polar metabolites from colored sweet potato (Ipomoea batatas L.) tubers

Abstract

We determined the phytochemical diversity, including carotenoids, flavonoids, anthocyanins, and phenolic acids, in sweet potatoes (Ipomoea batatas L.) with distinctive flesh colors (white, orange, and purple) and identified hydrophilic primary metabolites. Carotenoid content was considerably higher in orange-fleshed sweet potatoes, wherein β-carotene was the most plentiful, and anthocyanins were detected only in purple-fleshed sweet potatoes. The levels of phenolic acids and flavonoids were relatively higher in purple-fleshed sweet potatoes than those in the other two varieties. Forty-one primary and 18 secondary metabolite profiles were subjected to multivariate statistical analyses, which fully distinguished among the varieties and separated orange- and purple-fleshed sweet potatoes from white-fleshed sweet potatoes based on the high levels of sugars, sugar alcohols, and secondary metabolites. This is the first study to determine comprehensive metabolic differences among different color-fleshed sweet potatoes and provides useful information for genetic manipulation of sweet potatoes to influence primary and secondary metabolism.

Keywords: carotenoid; metabolomics; partial least squares discriminant analysis; phenolic acid; sweet potato.