title: Superheated liquid and supercritical denatured ethanol extraction of antioxidants from Crimson red grape stems.
abstract: Grapes are widely known for health benefits due to their antioxidant content. In wine production, grape stems are often discarded, though they has a higher content of antioxidants than the juice. The effectiveness of using an environmentally friendly solvent, ethanol, as a superheated liquid and supercritical fluid to extract antioxidant compounds from grape stems of organically grown Crimson Seedless grapes was evaluated. The Ferric Reducing Ability of Plasma (FRAP) assay and the Total Phenolic Content (TPC), or Folin-Ciocalteu assay, were used to quantify the antioxidant power of grape stem extracts. The extractions were performed at temperatures between 160°C and 300°C at constant density. It was found that the optimal extraction temperature was 204°C, at superheated liquid conditions, with a FRAP value of 0.670 mmol Trolox Equivalent/g of dry grape stem. The FRAP values were higher than other studies that extracted antioxidants from grape stems using single-pass batch extraction.
authors.affiliation: Kettering University 1700 University Ave Flint Michigan 48504.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wenzel
authors.affiliation: Kettering University 1700 University Ave Flint Michigan 48504.
authors.forename: Cheryl Storer
authors.initials: CS
authors.lastname: Samaniego
authors.affiliation: Kettering University 1700 University Ave Flint Michigan 48504.
authors.forename: Lihua
authors.initials: L
authors.lastname: Wang
authors.affiliation: Kettering University 1700 University Ave Flint Michigan 48504.
authors.forename: La'Shyla
authors.initials: L
authors.lastname: Nelson
authors.affiliation: Kettering University 1700 University Ave Flint Michigan 48504.
authors.forename: Korrine
authors.initials: K
authors.lastname: Ketchum
authors.affiliation: Kettering University 1700 University Ave Flint Michigan 48504.
authors.forename: Michelle
authors.initials: M
authors.lastname: Ammerman
authors.affiliation: Kettering University 1700 University Ave Flint Michigan 48504.
authors.forename: Ali
authors.initials: A
authors.lastname: Zand
keywords: Antioxidant activity; Crimson seedless grape; FRAP assay; grape stem extracts; supercritical ethanol extraction; superheated liquid ethanol extraction, TPC