Abstract

PALADINO, Silvia C.  and  ZURITZ, Carlos A.. Antioxidant grape seed (Vitis vinifera L.) extracts: efficiency of different solvents on the extraction process. Rev. Fac. Cienc. Agrar., Univ. Nac. Cuyo [online]. 2011, vol.43, n.1, pp.187-199. ISSN 1853-8665.

The objectives of this work were to compare the extracting efficiency of phenolic compounds from grape seeds of different solvents; to evaluate the antioxidant activity by means of the reducing power of the extracts obtained and to analyze the extraction process at different temperatures with the most efficient solvent. Seeds from grapes variety Cabernet Sauvignon from red-wine vinification were employed. The solvents and temperatures use to evaluate extracting efficiency were: distilled water at 90°C, a 70% methyl alcohol solution at 30°C, a 75% acetone solution at 30°C and a 20% ethyl alcohol solution at 30°C. The concentration of phenolic compounds was determined using a modified Folin-Ciocalteu method. The reducing power was determined using the method of Oyaizu. Water at 90ºC was the most efficient solvent for extraction of grape seed phenolic compounds (12.587 mg/g dry matter); 75% acetone solution at 30°C extracted 7.268 mg phenolic compounds/g dry matter; 70% methyl alcohol at 30°C extracted 0.963 mg phenolic compounds/g dry matter and 20% ethyl alcohol at 30°C extracted 0.799 g phenolic compounds/g dry matter. The extraction process was evaluated with water at 60 and 90°C. Water at 90°C extracted almost five times more polyphenols than water at 60°C after five hours of treatment.

Keywords : Polyphenols; Grape seed extracts; Antioxidants; Reducing power; Extraction process.

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