ABSTRACT
Solid and liquid by-products produced during cultivation and processing of sweet potato are important sources of phytochemicals. Phenolic compounds are the predominant antioxidant compounds in leaves showing considerable antioxidant capacity. Purple SP and its by-products contain anthocyanins, predominately cyanidin and peonidin glycosides acylated with p-hydroxybenzoic acids, ferulic acid, and caffeic acid, and exhibit functional properties such as antioxidants, hepato-protection (Hwang, Choi, Choi, Chung, and Jeong 2011), and memory enhancing. Other important polyphenols detected in these by-products are chlorogenic acid, chlorogenic acid-3-glucose, caffeic acid, and quinic acid. On the other hand, flavonoids and carotenoids are mainly present in sweet potato leaves. Lutein, a carotenoid from leaves, can be used as a food color with additional health benefits. Moreover, the extracts obtained from sweet potato by-products also showed inhibitory effects against the growth of Escherichia coli, Bacillus spp, Aspergillus niger, Salmonella enterica Typhi, etc. Proper optimized techniques are required for recovering functional compounds from these by-products.
