The effects of cellulase and amylase hydrolysis on solubility, total anthocyanin cotent (TAC) and total antioxidant activity (TAA) of purple sweet potato (Ipomoea batastas L.) drink

Abstract

Purple sweet potato consists of great value of nutrients and it has been developed into commercialized drink for convenience and long-lasting purposes. The aim of the study was to investigate the appropriate hydrolysis conditions of cellulase and amylase on purple sweet potato (PSP) drink including incubation time (50 minutes to 80 minutes) and cellulase concentration (0.5% to 2%) with fixed 1.5% amylase concentration to obtain the highest solubility. From that optimum condition, TAC, TAA, TPC and reducing sugar of cellulase and amylase treated purple sweet potato drink was then compared with no enzyme treated PSP drink and amylase treated PSP drink. The PSP drink was developed into the product with sugar, skim milk and guar gum after treating with cellulase and amylase. The sensory test was built to study the consumer acceptability of amylase hydrolyzed PSP drink, cellulase and amylase hydrolyzed drink with and without gum. After hydrolyses, the appropriate hydrolysis conditions were 50-minute incubation and 1.5% cellulase concentration which solubility percentage was 72.42%, total anthocyanin content was 21.71 mg/100 gram db and total antioxidant activity was 72.46%. Moreover, the hydrolysis of cellulase was not as effective as that of amylase. Consequently, PSP drink treated with cellulase and amylase and guar gum achieved the highest degree of satisfaction at appearance (3.75), taste (3.92) and overall acceptability (3.72), scored given by the panelists. Keywords: purple sweet potato, amylase, cellulase, solubility, anthocyanin content, antioxidant activity, sensory evaluation.