Evaluation of Phytochemical and Mineral Composition of Malaysia’s Purple-Flesh Sweet Potato

Sweet potato (Ipomoea batatas (L.) Lam) is one of Malaysia’s underutilized main crops. However, systematic characterization of phytochemical and mineral contents of the sweet potato tuber and flour is still required for further specific food product development. Therefore, this study aims to evaluate the effects of the peeling conditions on the nutritional composition of sweet potato tuber and flour of the Anggun 1 cultivar. The following properties were investigated in the different peeling conditions of the sweet potato tuber (unpeeled, peeled, and skin only), i.e., the phytochemical properties (total phenolic, total flavonoid, anthocyanin content) and mineral elements (calcium and iron). The results indicated a significant interaction between the peeling conditions of the sweet potato tuber and flour on all the examined properties (p<0.05), total flavonoid content (2615.05 mg quercetin/100g and 3362.96 mg quercetinrties (p < 0.05). The unpeeled sweet potato tuber and flour had the highest value of total phenolic content (3142.98 mg GAE/100g and 4303.80 mg GAE/10/100g), anthocyanin (628.35 mg/100g and 960.30 mg/100g) and iron (5.45 mg/100g for flour only). Moreover, the result had indicated a higher calcium content (701.87 mg/100g) in the skin of the sweet potato. Therefore, this study provides a broad insight into the sweet potato’s phytochemical properties and the mineral composition, which can be used for further specific food product development and processing.