Extraction of total phenolics of sour cherry pomace by high pressure solvent and subcritical fluid and determination of the antioxidant activities of the extracts

High pressure liquid extraction (HPE) and subcritical fluid (CO2+ethanol) extraction (SCE) were used for the extraction of total phenolic compounds (TPC) from sour cherry pomace. Antiradical efficiency (AE) of the extracts was also determined. Ethanol was the solvent for HPE and co-solvent for SCE. Combinations of pressure (50, 125, 200MPa), temperature (20, 40, 60 degrees C), solid/solvent ratio (0.05, 0.15, 0.25g/ml) and extraction time (10, 25, 40min) were variables for HPE according to the Box-Behnken experimental design. The variables used for SCE were pressure (20, 40, 60MPa), temperature (40, 50, 60 degrees C), ethanol concentration (14, 17, 20wt%) and extraction time (10, 25, 40min). For HPE, TPC, and AE at the optimum conditions (176-193MPa, 60 degrees C, 0.06-0.07g solid/ml solvent, 25min) were found as 3.80mg gae/g sample and 22mg DPPH center dot/g sample, respectively. TPC and AE at the optimum conditions (54.8-59MPa, 50.6-54.4 degrees C, 20wt% ethanol, 40min) for SCE were determined as 0.60mg gae/g sample and 2.30mg DPPH center dot/g sample for sour cherry pomace, respectively.