Sweet potato (Ipomoea batatas Lam): a rich source of bioactive components and a promising crop for health promotion

This study evaluated antioxidant activity (AOA) and antioxidant components of three sweet potato (Ipomoea batatas Lam.) cultivars: Tainong 57 (TNG57), Tainong 66 (TNG66) and Tainong 73 (TNG73). Studied factors included extracting solvent, genotype, part of the root, drying method, fractionation method, storage temperature, and storage duration. Due to its high effectiveness and its relative lower toxicity, ethanol was the most suitable solvent. The three sweet potato cultivars showed good AOA. TNG73 had the highest phenolic content and AOA. TNG66 showed the highest carotenoid content. The skin samples had higher AOA and phenolic content than the flesh ones. Freeze-dried samples showed higher AOA and phenolic content than those submitted to other drying conditions. Four major antioxidant compounds were identified: catechin, rutin, gallic acid and beta-carotene. Decrease in AOA of the flesh samples was significant after five-month storage at room temperature and 10 months at 4ºC. An isolated starch pasting profile analysis suggested suitability of the three sweet potato cultivars for processing as gel foods or other food items that require gelatinization ability of the raw material.