|Vasse, Justine - Ecole Nationale|
Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2010
Publication Date: 3/6/2010
Citation: Breksa III, A.P., Takeoka, G.R., Hidalgo, M., Vilches, A.M., Vasse, J., Ramming, D.W. 2010. Phenolic Content of Raisin Grape Varieties and Genotypes. Food Chemistry. 121, 740-745. Interpretive Summary: Six raisin grape cultivars and ten new raisin grape selections were analyzed for antioxidant activity (ABTS assay) and for total and individual phenolic compounds. Samples were freeze-dried and values are reported on a dry weight basis. Due to their higher antioxidant activities and higher concentrations of catechin and epicatechin compared to Thompson Seedless grapes, selections A56-66, A95-15 and A95-27 have the potential to be new commercial raisin grapes with improved nutritional properties.
Technical Abstract: Six raisin grape cultivars and ten new raisin grape selections were analyzed for antioxidant activity (ABTS assay) and for total and individual phenolic compounds. Samples were freeze-dried and values are reported on a dry weight basis. Antioxidant activity across the 16 samples ranged from 7.7 to 60.9 micromol Trolox/g DW, with A95-27 exhibiting the greatest activity. Total phenolic content, determined in gallic acid equivalents using the Folin-Ciocalteau assay, ranged from 316.3 to 1141.3 mg gallic acid/100 g DW and was strongly correlated (r = 0.990) with antioxidant results. Concentrations of individual phenolics were determined by HPLC. Trans-Caftaric acid was the predominant compound in all samples. A95-15 contained the lowest concentration (153.5 micro g/g DW) of caftaric acid, while Fiesta contained the highest concentration (598.7 micro g/g DW). Selections A56-66, A95-15, and A95-27 had much higher levels of catechin (86.5 to 209.1 micro g/g DW) and epicatechin (126.5 to 365.7 micro g/g DW) than the other samples.