Antioxidant capacity and phenolic content of grapes, sun-dried raisins, and golden raisins and their effect on ex vivo serum antioxidant capacity.
Grapes and raisins provide phenolic antioxidants, which contribute to their potential health benefits. The objectives of this study were to compare the antioxidant capacity and phenolic content of green Thompson seedless grapes (the most common variety of grapes consumed in the United States), sun-dried raisins, and golden raisins (both produced from Thompson seedless grapes) and to observe the effects of their consumption over 4 weeks in 15 healthy human males with a cross-over design. The oxygen radical absorbance capacity (ORAC) (positive statistical significance for grapes after 2 weeks and golden raisins after 3 weeks), serum oxidation (positive statistical significance for golden raisin lag time after 4 weeks), total phenolics (no significant effects), and C-reactive protein (no significant effects) were monitored. Immediately postconsumption, there were some significant nonpositive changes. It is hypothesized that these negative results may be explained by postprandial oxidation, a known effect after carbohydrate consumption. Golden raisins had the highest antioxidant capacity and phenolic content. The consumption of a serving of grapes or raisins each day, in addition to a typical diet, may not be sufficient to overcome postprandial oxidation when consumed with other high carbohydrate foods but may have beneficial antioxidant effects over time.
Parker
Tory L
TL
Department of Food Science and Human Nutrition, Univeristy of Illinois, 1201 West Gregory Drive, 259 ERML, Urbana, Illinois 61801, USA.
Wang
Xiao-Hong
XH
Pazmiño
Jorge
J
Engeseth
Nicki J
NJ
D000293:Adolescent; D000328:Adult; D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology; D002097:C-Reactive Protein / Q000032:analysis; D003890:Desiccation; D004032:Diet; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010636:Phenols / Q000032:analysis* / Q000097:blood; D017382:Reactive Oxygen Species / Q000737:chemistry; D027843:Vitis / Q000737:chemistry*
D000975:Antioxidants; D010636:Phenols; D017382:Reactive Oxygen Species; D002097:C-Reactive Protein