Author(s)

Antonia Llobera

Department of Chemistry, University of Illes Balears, Palma de Mallorca, Spain..

The antioxidant activity of 80% ethanol and 70% acetone extracts of stems from red and white grapes (Vitis vinifera) used in wine industry were evaluated to determine their feasibility as natural antioxidants. The results showed that all grape stem extracts were rich in total polyphenolic compounds and flavanols and had clear antioxidant activities. The free radical-scavenging capacity of the extracts was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The extracts obtained from red grape stem present EC₅₀ values of 0.14 g dm/g DPPH (acetone extract) and 0.20 g dm/g DPPH (ethanol extract) while the extracts obtained from white grape stem present EC₅₀ values of 0.26 g dm/g DPPH (acetone extract) and 0.37 g dm/g DPPH (ethanol extract). There are significant correlations between the total content of polyphenols and the antioxidant activity (R² = 0.9352) and between the flavanols content and the antioxidant activity (R² = 0.9404) of the grape stem extracts obtained.

Grape Stem; Antioxidant Activity; Stem Extracts; Polyphenols; Radical Scavenging Activity; DPPH

A. Llobera, "Study on the Antioxidant Activity of Grape Stems (Vitis vinifera). A Preliminary Assessment of Crude Extracts," Food and Nutrition Sciences, Vol. 3 No. 4, 2012, pp. 500-504. doi: 10.4236/fns.2012.34070.