Free radical scavenging of grape pomace extracts from Cabernet sauvingnon (Vitis vinifera)
2008
de Campos, Luanda M.A.S. | Leimann, Fernanda V. | Pedrosa, Rozangela Curi | Ferreira, Sandra R.S.
Pressed grape pomace obtained from the wine production of Cabernet sauvignon (Vitis vinifera) vintage was dried until 9.8% moisture content, ground and submitted to extraction of soluble components from different extraction techniques. Low pressure extractions were performed with ethanol maceration followed by fractionation with n-hexane, dichloromethane, butanol and ethyl acetate. These solvents were furthermore applied for soxhlet extraction. Supercritical fluid extraction (SFE) was also performed to obtain grape pomace extracts by using pure CO₂ and CO₂ with ethanol as co-solvent in concentrations of 10, 15 and 20%w/w. The operating condition used in high pressure extractions was 150bar and 40°C. The antioxidant activity of the grape pomace extracts was determined considering the free radical scavenging assay using 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and was correlated with the total phenol content determined according to the Folin-Ciocalteu method. The results obtained in DPPH tests indicate the highest antioxidant activity of 96.6±0.3%AA, with an IC₅₀ value of 13±1, for the extracts obtained with ethyl acetate in solid-liquid extraction. The highest yield values were achieved in soxhlet extraction with ethanol (13.2%w/w) and with butanol (12.2%w/w), and also by SFE with 15% ethanol (9.2%w/w). The lipophilic composition of grape pomace extracts was evaluated by gas chromatography-mass spectrometry with the identification of components like linoleic acid and ethyl linoleate, with important therapeutic activities.
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