Functional fabric treatment using tannic acid and extract from purple-fleshed sweet potato

Purple-fleshed sweet potato (PSP) has a reddish purple color with high amounts of anthocyanins and phenolic acids, both of which have various health-promoting effects. The acylated anthocyanins present in PSP are more heat-resistant than the nonacylated types found in other plants. Therefore, PSP extract was considered as a natural pigment and functional agent for textile dyeing and/or finishing processes. Here, wool and cotton fabrics are pretreated by a tannic acid aqueous solution to increase their dyeability and then dyed by PSP extract. The dyed fabrics are then investigated by various analysis techniques. The results revealed that wool and cotton fabrics can be dyed bluish red through the pretreatment and dyeing process. The wool and cotton fabrics also showed antibacterial and antioxidant characteristics.