Major phenolics in apple and their contribution to the total antioxidant capacity.
The contribution of each phytochemical to the total antioxidant capacity of apples was determined. Major phenolic phytochemicals of six apple cultivars were identified and quantified, and their contributions to total antioxidant activity of apples were determined using a 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and expressed as vitamin C equivalent antioxidant capacity (VCEAC). Average concentrations of major phenolics and vitamin C in six apple cultivars were as follows (mg/100 g of fresh weight of apples): quercetin glycosides, 13.20; procyanidin B(2), 9.35; chlorogenic acid, 9.02; epicatechin, 8.65; phloretin glycosides, 5.59; vitamin C, 12.80. A highly linear relationship (r (2) > 0.97) was attained between concentrations and total antioxidant capacity of phenolics and vitamin C. Relative VCEAC values of these compounds were in the order quercetin (3.06) > epicatechin (2.67) > procyanidin B(2) (2.36) > phloretin (1.63) > vitamin C (1.00) > chlorogenic acid (0.97). Therefore, the estimated contribution of major phenolics and vitamin C to the total antioxidant capacity of 100 g of fresh apples is as follows: quercetin (40.39 VCEAC) > epicatechin (23.10) > procyanidin B(2) (22.07) > vitamin C (12.80) > phloretin (9.11) > chlorogenic acid (8.75). These results indicate that flavonoids such as quercetin, epicatechin, and procyanidin B(2) rather than vitamin C contribute significantly to the total antioxidant activity of apples.
Lee
Ki Won
KW
Department of Food Science and Technology, Cornell University, Geneva, NY 14456, USA.
Kim
Young Jun
YJ
Kim
Dae-Ok
DO
Lee
Hyong Joo
HJ
Lee
Chang Yong
CY
D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D001205:Ascorbic Acid / Q000032:analysis / Q000737:chemistry; D052160:Benzothiazoles; D044946:Biflavonoids; D002392:Catechin / Q000032:analysis / Q000737:chemistry; D005419:Flavonoids / Q000032:analysis / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry; D005638:Fruit / Q000737:chemistry*; D027845:Malus / Q000737:chemistry*; D010636:Phenols / Q000032:analysis* / Q000737:chemistry; D044945:Proanthocyanidins; D011794:Quercetin / Q000032:analysis / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry
D000975:Antioxidants; D052160:Benzothiazoles; D044946:Biflavonoids; D005419:Flavonoids; D005609:Free Radicals; D010636:Phenols; D044945:Proanthocyanidins; D013451:Sulfonic Acids; C479578:procyanidin B; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C017674:procyanidin; D002392:Catechin; D011794:Quercetin; D001205:Ascorbic Acid