engleski

Polyphenol extraction from grape seed winery waste (cv. Merlot) using different solvents and extraction time

Grape seeds are byproducts from wine industry and they are rich source of polyphenols which can be used in production of new added value products. It is important to select efficient solvent and time of extraction to achieve high yield of polyphenols. The aim of this work was to determine the effect of solvent and extraction time on the content of extracted polyphenols from grape seeds previously deffated using supercritical CO2. Extraction was performed by using two extraction solvents: 50 % (v/v) aqueous solution of ethanol and acetone through 15, 30 and 45 minutes in ultrasonic bath at 30 °C. Total phenolic content (TPC), hydroxycinnamic acids (THCA), flavonols (TF) and antioxidant activity were determined with spectrometrically methods. The results showed that 50 % acetone aqueous solution is more efficient solvent than 50 % ethanol for extraction of polyphenol compounds, and at all extraction times the amount of all polyphenolic compounds were higher in acetone extracts. However, the content of polyphenol compounds did not change uniformly with the time of extraction in acetone and ethanol extracts. The TPC, THCA were found in highest amount in acetone extracts after 45 minutes and TF after 15 minutes of extraction, while in ethanol extracts TPC, THCA and TF were found in highest amount after 15 minutes of extraction. Antioxidant activity measured by DPPH method was similar in all grape seed extracts regardless of the solvent and extraction time. Results indicated that solvent affected more on polyphenol extraction from grape seeds than extraction time, and grape seeds can be considered as valuable source of polyphenolic compounds with antioxidant activity.

grape seed ; winery waste ; polyphenols ; extraction

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