DOI: 10.5593/SGEM2016/B61/S25.105


D.G.Dumbrava, D.N.Raba, C. Moldovan, F. Radu, M.V.Popa
Wednesday 7 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-68-1 / ISSN 1314-2704, June 28 - July 6, 2016, Book6 Vol. 1, 791-798 pp


In this work we aimed to determine antioxidant activity (by CUPRAC method), the content of ascorbic acid (by iodometric method) and polyphenols (by Folin-Ciocâlteu method) in the pulp and skins of some grapes varieties from the Romanian market. It was found that for all four grape varieties analyzed (Negru de Drăgăşani, Coarna Neagră, Cardinal and Victoria), the skins was much richer in vitamin C than the pulp. Grape variety with the highest concentration of ascorbic acid in the skin was Coarna Neagră (44.00 mg/100g), and the highest concentration in pulp was found in the Victoria variety (18.85 mg/100g). It was also found that the grapes skins was much richer in polyphenols than the pulp. The highest content of polyphenols was found in Coarna Neagră grape skins (2.289 mg gallic acid/g fresh weight), followed by the skins of grape Victoria (1.746 mg gallic acid/g fresh weight) and Cardinal (1.719 mg gallic acid/g fresh weight). Grape variety with the poorest polyphenols content was Negru de Drăgăşani (1.104 mg gallic acid/g in the skins or 0.128 mg gallic acid/g in pulp). And in terms of antioxidant properties it was observed that the grape skins has a stronger antioxidant activity than the pulp. This highest antioxidant activity was registered in the skins of grape Coarna Neagră (2.049 mM Trolox/g), followed by the skins of grape Victoria (2.019 mM Trolox/g) and Cardinal (1.890 mM Trolox/g). The pulp of grapes most valuable in terms of antioxidant activity was the variety Victoria (0.549 mM Trolox/g), while the variety Cardinal pulp presents the lowest antioxidant activity (0.426 mM Trolox/g).

Keywords: grapes, polyphenols, antioxidant activity.