Solvent and solvent to sample ratio as main parameters in the microwave-assisted extraction of polyphenolic compounds from apple pomace

Microwave-assisted extraction (MAE) in the presence of ethanol and water as solvents was applied as a modern technique to extract polyphenolic compounds from apple pomace and the results were compared to those of Soxhlet extraction and maceration. Various experimental conditions such as microwave power, extraction time, type of solvent, and solvent to sample ratio were considered for the study. Increasing microwave power (from 90 to 360 W) resulted in lower extraction yields. Ethanol-water (at the ratio of 65 to 35) was the best solvent for MAE. However, for the sake of higher water contribution in the extraction, a ratio of 35:65 (ethanol:water) can be selected for a recovery of −90% at a shorter extraction time. The best solvent to sample ratio was found at 20 to 1 level. When used for the extraction of polyphenolic compounds from apple pomace, MAE was faster than maceration and Soxhlet methods.