Supercritical fluids are tunable solvents that may be used to extract a wide variety of chemical species from plant materials. The solvating and extracting properties of supercritical fluids are dependent upon composition, temperature, pressure, and density as well as retention time. For this work, the extraction effects of supercritical carbon dioxide, hexane, methanol, water, and ethanol were evaluated for their ability to extract phenolic and other compounds from the stems of commercially available seedless red grapes. The extractions were performed batch-wise in a Parr Instrument 26 mL 316 stainless steel bolt closure reactor. Extraction conditions were selected considering the critical point of the solvent. Some of the conditions evaluated included 47 �C and 13.2 MPa for carbon dioxide and 402 �C and 23.1 MPa for water. The extracts were analyzed using GC-MS for composition and tested for antioxidant properties using the FRAP assay. Chemical species extracted include various methoxyphenols, dihydroxyacetophenone, 2-methyl furan, and others. The extracts ranged from less than 1 to up to 8 mmol of antioxidants per gram of extracted material. The chemical species extracted, selectivity of the extraction based upon supercritical fluid used, and antioxidant characteristics will be discussed.

Antioxidant properties of extracted phenolic compounds from grape stems using supercritical fluids

246th National Meeting (2013)

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