The Correlation between Total Phenol and Antioxidant Capacity of Sweet Potato (Ipomoea batatas L.) with Varying Flesh Color

摘要

The study established baseline data on the total phenol content and antioxidant activities of 36 sweet potato (Ipomoea batatas) cultivars with distinctive flesh color (white, yellow, orange and purple) grown in Pijit Province in the northern part of Thailand. Total phenol were measured using the Folin-Ciocalteau method while antioxidant capacity in sweet potato flesh was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH). Total phenol content ranged from 75.47-1,283.37 μg gallic acid equivalent (GAE) g~(-1) dry weight. The highest phenolic content was found in cultivar 'PJ25' (purple fleshed) and lowest in cultivar 'PJ18' (orange fleshed). Antioxidant capacity in different flesh color ranged from 72.1-84.56% of DPPH inhibition. The highest total phenol was concomitant with the highest antioxidant activity which was 84.56% for DPPH radical scavenging activity on a dry weight in cultivar 'PJ25'. Significant (*P<0.05) positive correlation was observed between total phenol content and antioxidant capacity (%inhibition) for DPPH radical scavenging activity in white (R2=0.652), yellow (R2=0.5386), orange (R2=0.6518) and purple (R2=0.899) fleshed sweet potatoes.