Phenolic levels have been analyzed in several grape cultivars that are suited for growing in southeastern Nebraska. The phenolic levels of these cultivars are not known to have been previously published. The polyphenol content of fruits and fruit products such as wine have been shown to be directly correlated to the antioxidant potential of the product. Antioxidants help to prevent the effects of aging and age-associated diseases. The grape cultivars in the study are grown primarily for wine production, but also as fresh table grapes and for making juice and jellies. The total phenolic content is being analyzed by the Folin-Ciocalteu method. Of the red grapes, `St. Croix' and `Frontenac' have the highest levels of polyphenols, followed by `Chambourcin' and `deChaunac', with levels varying from 1.4–4.9 mg·g-1 (polyphenols/grape), measured as gallic acid equivalents (GAE). The white grapes `Vignoles' and `LaCrosse' have total phenolic levels of 1.4 to 2.2 mg·g-1 (polyphenols/grape), also measured as gallic acid equivalents (GAE).
PHENOLIC CONTENT AND ATIOXIDANT ACTIVITY OF RED GRAPES FROM INTERNATIONAL, LOCAL AND HYBRID GRAPEVINE VARIETIES GROWN IN CENTRAL NORTHERN BULGARIA
