Quantification of phenolic acids and antioxidant activity in sweetpotato genotypes

Abstract

Phenolic acid composition and antioxidant activity in roots of 14 commercially important sweetpotato genotypes were evaluated. Significant differences in total phenolics, individual phenolic acids, and antioxidant activity were found among the different sweetpotato genotypes. Total phenolic content, expressed in terms of chlorogenic acid equivalent, in different genotypes ranged from 1.4 to 4.7 mg g −1 dry weight (DW). Antioxidant activity was evaluated as Trolox equivalent, ranging from 1.3 to 4.6 mg g −1 DW. The highest total phenolic content and antioxidant activity were observed in a purple-fleshed genotype. Chlorogenic acid and 3,5-dicaffeoylquinic acid were the predominant phenolic acids, while caffeic acid was the least abundant in most genotypes. The highest content of chlorogenic acid (422.4 μg g −1 DW) was present in a white-fleshed cultivar ‘Quarter Million’ imported from Jamaica. However, a purple-fleshed genotype had the highest amounts of 3,5-dicaffeoylquinic (485.6 μg g −1 DW), 3,4-dicaffeoylquinic (125.6 μg g −1 DW), 4,5-dicaffeoylquinic (284.4 μg g −1 DW), and caffeic (20.5 μg g −1 DW) acids.