Evaluation of Eight Orange Fleshed Sweetpotato (OFSP) Varieties for Their Total Antioxidant, Total Carotenoid and Polyphenolic Contents

Abstract

Eight varieties of OFSP whose yields ranged from 6 t/ha (Caromex) to 15.22 t/ha (BF82xCIP-18) have a water content less than the current value observed for OFSP (71%).These varieties have been studied for their total antioxidant contents (TAC), total polyphenolic contents (TPC) and total carotenoid contents (TCC) using Ferric Reducing Antioxidant Power (FRAP), Folin-Ciocalteu reagent (FCR) and a method described by McMurry respectively. TAC differed significantly (p < 0.05) depending on the variety. Among the varieties obtained by crossing, BF92xResisto-14 and BF92xCIP-6 with the highest levels of total antioxidants (respectively 4.12 and 3.04 mg of Trolox equivalent/g of dw), had also the highest levels of total polyphenols (respectively 2.432 and 2.269 mg of Gallic acid equivalents/g of dw) and total carotenoids (respectively 0.180 and 0.132 mg of Beta-carotene equivalents/g of dw). There was a good correlation first, between the TAC and the TPC (r² = 0.957) and between the TAC and the TCC (r² = 0.867) on the other. Antioxidant activities observed may be due to the effect of synergy between polyphenols and carotenoids.

Keywords: Yield, OFSP extracts, total antioxidant content, total polyphenolic content, total carotenoid content, FRAP, FCR