Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/4/2014
Publication Date: 5/7/2014
Citation: Bakota, E.L., Winkler-Moser, J.K., Berhow, M.A., Liu, S.X. 2014. Antioxidant activity of grape pomace extracts derived from Midwestern grapes in bulk oil and oil-in-water emulsions [abstract]. American Oil Chemists' Society.
Technical Abstract: Natural antioxidants to extend the shelf life and fry life of edible oils are in high demand. Grape pomace is an abundant, inexpensive, and often discarded source of polyphenolic antioxidants. We examined pomace from nine varieties of Midwestern grapes for total phenolic content and antioxidant activity via the ABTS assay. Ethanolic extracts produced from the pomace of each grape variety were then added to bulk soybean oil as well as oil-in-water emulsions to determine antioxidant activity of the extracts in lipid systems. It was found that while the extracts had relatively little effect in bulk oil, we observed dose-dependent antioxidant effects of the extracts in oil-in-water emulsions. Oxidation in heated bulk oil was monitored by total polar compounds and TAG polymerization. Oxidation in emulsions was measured by peroxide value, headspace oxygen measurements, gas chromatography of headspace volatiles, and fatty acid composition. In general, pomace extracts derived from red grapes outperformed those from white grapes, with the Marechal Foch variety showing the highest antioxidant activity overall. Grape pomace in general represents an underutilized source of antioxidants for oil-in-water emulsions.