Survey of solvents for the extraction of grape seed phenolics

The effect of different solvents on the extraction of some phenolic compounds from grape seeds was investigated. The main compounds identified by high performance liquid chromatography were gallic acid, (+)‐catechin, (‐)‐epicatechin, the dimeric procyanidins B1 and B2, the trimeric procyanidin C1 and epicatechin gallate. The solvents tested were water, absolute ethanol, 75% ethanol, acetone, 70% acetone, methanol, n ‐butanol, diethyl ether, ethyl acetate and a combination of diethyl ether followed by ethyl acetate. Results showed that methanol was the best solvent for the extraction of (+)‐catechin, (‐)‐epicatechin and epigallocatechin, whereas 70% acetone yielded the largest amounts of procyanidins and 75% ethanol yielded the largest amount of gallic acid. The greatest amount of total phenols was extracted by 70% acetone.