Effect of Adsorbent and Ion Exchange Resin Applications on Total Phenolic Content and Antioxidant Activity of White and Red Grape Juices

Abstract

In this study activated carbon, Dowex^® 50Wx8-100 and Amberlite^® XAD-16 were applied to white and red grape juices to determine effects on total phenolic and antioxidant activity of juices. Total phenolic and antioxidant activity (DPPH, ABTS and FRAP) analyses were performed in control and resin applied grape juices. Total phenolic content of white grape juice was found as 2.28 g GAE/kg dry weight. Total phenolic contents of white grape juices were decreased to 14.00, 14.00 and 23.24%, respectively, by activated carbon, Dowex^® 50Wx8-100 and Amberlite^® XAD-16 applications. Similar to white grape juice, the most reduction in the total phenolic content of the red grape juice were obtained by Amberlite^® XAD-16 application. The antioxidant activities of both grape juices were also decreased by resin application According to the obtained results, the lowest antioxidant activity values were observed in white grape juices applied to Dowex^® 50Wx8-100, and in red grape juices applied to Amberlite^® XAD-16.