Optimization of extraction parameters of phenolic compounds from Algerian fresh table grapes, (Vitis Vinifera)

The aim of this study is to optimize extraction parameters of phenolic compounds from one variety of Algerian table grapes. The effect of different solvents: distilled water, acetone (20, 40, 60 and 80%), methanol (20, 40, 60 and 80%) and ethanol (20, 40, 60 and 80%), temperature (25, 40, 50, 60 and 70°C), time (30, 60, 90 and 120 min) and four successive extractions were tested. It was found that the solvent nature, time and temperature have a significant effect on total polyphenols (TPP) recovered from the grape. The best extraction conditions were as follows: methanol 80% at 60°C during 30 minutes and three consecutive extractions with content of TPP extracted of 216,81 mg GAE/100 g of fresh weight (FW). This indicates that the rate of polyphenols extracted from grapes depends only on the extraction method used and that Algerian table grape fruits can be considered as a natural source of phenolics compounds with good antioxidant capacity. This study on the optimization of the extraction parameters of phenolic compounds from grapes is very original on scale of Algeria. It is the first made on a variety grown in this country.