(504d) Extraction of Antioxidants from Chokeberries Using Supercritical Carbon Dioxide with Ethanol

Chokeberries, a shrub native of eastern North America, are widely known for their astringent properties and the berry is used as a flavorant in wines, jams, and tea.  In addition, chokeberries are high in antioxidant polyphenolic compounds and are being evaluated for their effects in preventing disease.  Due to unique solvent properties, including selectivity and diffusivity, supercritical fluids may be used to extract antioxidant compounds from plants.  The extraction of antioxidant compounds from chokeberry pomace was evaluated using supercritical carbon dioxide with an ethanol modifier.  Ethanol was added to increase the dielectric constant of the fluid to improve extraction selectivity.   The effects of temperature, ethanol proportion, and pressure upon the extraction of antioxidants were evaluated using a factorial design of experiments.  Temperature was varied from 50 to 80°C, pressure between 15 and 30 MPa, and ethanol was varied between 5 and 15 wt-%.  The extractions were performed batch-wise using a Parr Instruments 26 mL 316 stainless steel bolt-closure reactor.  The Ferric Reducing Ability of Plasma (FRAP) Assay and the Total Phenolic Content (TPC) Assay were used to quantify the antioxidant power of the chokeberry extracts.  The extracts were also evaluated by HPLC and GCMS.  The chemical species extracted, antioxidant characteristics, and optimal extraction conditions will be discussed.