The Effect of Purple Yam (Dioscorea Alata, L) Blanching Time on Anthocyanins Content and Antioxidant Activity

Abstract

This study aimed to determine the effect of purple yam blanching treatments on anthocyanin content, phenolics content and antioxidant of activity. Blanching was done by steam blanching for  4, 8, and 12 minutes  and  without blanching as a control. The results showed that blanching time affected  anthocyanins level, phenolics content and antioxidant activity as determined by DPPH and radical scavenging activity (RSA) methods. Blanching for 8 and 12 minutes  increased anthocyanins level (2.4 to 2.5 times), phenolics content (1.3 to 1.6 times), and antioxidant activity of purple yam compared to those without blanching. Antioxidant activities of purple yam blanching were 8-minute blanching ≥ 12-minute blanching = BHT > without blanching > 4-minute blanching . The level of total anthocyanins and phenolics content were significantly correlated with antioxidant activity as measured by radical scavenging activity.