A Screening Analysis of the High-Pressure Extraction of Anthocyanins from Red Grape Pomace with Carbon Dioxide and Cosolvent

In the work described here, a set of screening factorial design experiments was carried out in order to study the extraction process of anthocyanins from red grape pomace with carbon dioxide, along with either methanol or water as cosolvent, at high pressure. The variables studied were pressure, temperature, solvent flow-rate, cosolvent percentage, cosolvent type (methanol or water) and extraction time. The quantification of the total amount of anthocyanins was performed by a colorimetric method. The results of the ANOVA study show a strong influence of the type and percentage of cosolvent. The best results were obtained with 20 mol-% of methanol, 100 bar, 60 degrees C and a flow-rate of 22 mmol/min after two hours of extraction.