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G. Kroyer:
"Bioactive Compounds and radical scavenging properties of grape pomace";
Acta Biochimica Polonica, 55, Suppl. 1 (2008), 27.

Bioactive Compounds and radical scavenging properties of grape pomace

Gerhard Kroyer

Institute of Chemical Engineering, Department of Natural Products and Food Chemistry, University of Technology, Vienna, Austria

There is a growing interest in the food industry and in preventive health care in the development of natural antioxidants from plant materials. Consumption of a diet rich in antioxidant active polyphenol compounds has been linked with a reduced risk for cardiovascular diseases and certain types of cancer. Grape seeds are well studied in regard to their antioxidant activity due to their remarkable content of polyphenol substances. Based on this evidence the evaluation of the antioxidant properties of grape pomace might be of great evidence.
The objective of this study was to quantify the total polyphenol compounds and to evaluate the antioxidant and free radical scavenging properties of grape pomace of especially in certain regions of Austria cultivated grape varieties for the production of the unique Austrian wine called "Uhudler".
The grape pomace was dried, finely ground and extracted individually with ethanol, 50% ethanol in water and water. The obtained solid extracts were analyzed for their content of total polyphenols (Folin-Ciocalteu method). The antioxidant activities were determined with the DPPH* radical scavenging method in terms of their Efficient Concentration EC50 (mg antioxidant /mg DPPH*).
Above all the ethanolic grape pomace extracts showed remarkable amounts of total polyphenols and considerable free radical scavenging activity. The highest amounts of total polyphenols (mg/g) were found in the ethanol/water extract (41,2) and the ethanol extract (35,4) compared to the water extract (14,6). Correlating with the polyphenol content, the highest antioxidant and radical scavenging capacity was observed in the ethanol/water extract of the grape pomace (EC50: 11,5), followed by the ethanol extract (EC50: 15,7), whilst the water extract showed relatively minor inhibitory effectiveness (EC50: 40,9).
The results indicate that ethanol extracts from grape pomace, which is derived from the production of "Uhudler" wine, have remarkable antioxidative and radical scavenging properties in correlation with their content of total polyphenol substances. An application as potent natural antioxidant additive for food products and as dietary supplement seems to be worth considering, particularly in consideration of their beneficial impact to physiological degenerative processes, and would be helpful in maintaining and promoting health.

grape pomace, polyphenols, antioxidant activity, radical scavenging properties

http://publik.tuwien.ac.at/files/PubDat_168971.doc