Carotenoids, phenolics and antioxidant properties of different sweet potatoes (Ipomoea batatas) varieties

Abstract

Sweet potato (Ipomoea batatas) is one of the most important tuber crops for fresh consumption in Malaysia. However, it is not fully utilized with an approximately 30 % of the whole part sweet potato especially its skin is disposed upon consumption. Sweet potato contains abundant of valuable compounds such as carotenoids and phenolics with pharmaceutical values. This research was conducted to extract, quantify and determine the carotenoids, phenolics and antioxidant activity of skin and flesh from varieties of sweet potatoes. Extraction using acetone was carried out due to its ability to dissolve both polar and non-polar substances. Results exhibited that orange flesh sweet potato consisted of the highest total carotenoid content (187.88 ± 3.27 µg/g) while purple flesh comprised the highest total phenolic content (96.00 ± 1.3 mgGAE/g). Dark purple skin sweet potato was determined to exhibit the highest antioxidant activity (93.21 ± 1.33 %) when compared to others. Sweet potato particularly its skins could be utilised for value-added purposes such as food fortification, food additives, and animal feed enhancers instead of wasting them. Environmental problems due to food waste accumulation could be greatly reduced and data obtained could aid in future research.