High-pressure solubility data of system ethanol (1)+epicatechin (2)+CO2 (3)

Phenolic compounds are widely found in natural products and their effects on health have been largely studied, but most of the interest in these compounds stems from their antioxidant properties. The properties of these compounds differ from one to another; thus their isolation is of high interest. The most abundant phenolic compounds isolated from grape seed are the catechins family. Supercritical fluid extraction (SFE) affords big advantages over more conventional extraction techniques. The absence of both light and air during the process can reduce the incidence of degradation reactions. It is necessary the use of a cosolvent, because epicatechin solubility in supercritical CO2 is very small. The solubilities of epicatechin in supercritical phase were measured at 313.2 K, pressures ranging 80–120 bar and different mixtures ethanol–CO2 ranging from 5 to 30% of ethanol, in order to optimise the amount of epicatechin extracted. At a constant temperature, raising the pressure the solubility increases. Besides the solubility of epicatechin rises with the ethanol percentage. It seems possible the fractionation of the catechins family (catechin, epicatechin and quercetin) and resveratrol by supercritical extraction by varying the ethanol percentage and pressure. Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) EOS were successfully applied to the system ethanol+epicatechin+CO2.