Application of enzymatic treatments in concentration of pistachio hull extract by ultrafiltration

Abstract

In the present study, the influence of applying enzymes on the efficiency of the membraneused for the concentration of pistachio green hull extract was evaluated. Furthermore, theeffect of the obtained concentrated extract on the oxidative stability of flaxseed oil wasevaluated. The composition and antioxidant activity of the concentrated extracts were alsodetermined. Based on results, tannase treatment at 5.14 (U) led to significant decrease in membrane fouling percentage, content of tannins and IC50 in permeate of filtration (p<0.05) compared to control. However, this treatment significantly increased concentration of total phenols and flavonoids. Furthermore, galacturonic acid content statistically remained constant after treatment with tannase (p>0.05). Also, combined treatment with 17.4 (U) concentration of pectinase and 5.14 (U) concentration of tannase, had the lowest membrane fouling as well as IC50 and the most total phenol content (p<0.05) than other treatments. Therefore, combination of pectinase and tannase could be applied to reduce membrane fouling and optimize condition for production of natural antioxidant from aqueous extract of pistachio green hull. Moreover, 500 ppm of the obtained extract showed the best performance in preservation of flaxseed oil in comparison with other concentrations and commercial antioxidants.