Optimisation of polyphenolic compounds extraction from red grape pomace

Abstract

Grape pomace represent the main by-product of wine industry containing polyphenolic compounds with antioxidant and antibacterial activity. The aim of our study was to optimize their extraction using different organic solvents with different concentrations and different temperatures of extraction.The material used for extraction was grape pomace from three red varieties. As solvents, were used aqueous solutions from: ethanol, citric acid, acetone, sodium sulfite and glycerol, with different concentrations. The experimented temperatures for extraction were: 30, 60 and 90 C and the time of extraction was two hours for all the solvents. The best extraction was registered in case of acetone and ethanol. The nature of solvents influenced the proportion between the different classes of polyphenolic compounds extracted. The increasing temperature of the extraction had a positive effect on the extraction in case of all the solvents. Also, the increase of solvents concentration had a positive effect, up to a certain limit.