engleski

Extraction of Flavonoids from Grape Skin Pomace by High Voltage Electrical Discharges

Currently, new extraction techniques, such as high voltage electrical discharges assisted extraction (HVED) have been proposed for promoting polyphenols extraction from plant materials. HVED affects the cell walls and membranes which result with an extensive disintegration thus allows the release of intracellular compounds and enhance the extraction process. This technology can induce thermal, photonic, electrical and mechanical effects, hence could replace and improve conventional techniques in the recovery of plant polyphenols. Increased consumer awareness of healthy food products is driving investigation efforts to search for more natural antioxidants. On this matter, there is a growing interest in the exploitation of the residues generated by the wine industry since winery by-products have been highlighted as rich source of bioactive compounds. In particular, grape pomace could be an alternative source for obtaining natural antioxidants. Therefore, the objective of this study was to investigate the effects of HVED assisted extraction on the flavonoids recovery from red grape skin pomace. The effect of the solvent polarity (10, 30 and 50% aqueous ethanol (v/v)), extraction time (5 and 10 min) and frequency (60 and 120 Hz) were studied using a single-factor experiment. Obtained results showed that higher solvent polarity promote higher flavonoids solubility. A positive influence of HVED was demonstrated for higher frequency but only for extracts with 30 % ethanol. When regarding the extraction time, it can be observed that flavonoids recovery was higher under shorter extraction time for extracts with 10%, while extracts with 30% and 50% showed opposite trend. Finally, it can be concluded that HVED can be used for enhanced flavonoids extraction but the extraction conditions still needs further investigation.

flavonoids ; grape pomace ; extraction ; high voltage electrical discharges

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