Efficiency of pomegranate peel extracts in stabilization of sunflower oil under accelerated conditions

Pomegranate peels (PP) are underestimated as an agricultural waste. In this work, antioxidant efficacy of PP extracts has been estimated in stabilization of sunflower oil. Methanolic extract was found to be highest in yield, i.e. 29.16% and antioxidant activity 92.69% as compared to other solvents ranging in yield 13.96-21.14% and antioxidant activity 42.11-89.23%. Thermal stability of methanolic extracts was evaluated by heating the extract at 185 degrees C up to 80 min and evaluating the antioxidant activity of extract for different intervals during storage period and exhibited 66.23% inhibition of peroxidation after 80 min heating time. Methanolic extracts of PP at three concentrations, i.e. 250 (SFO-250), 500 (SFO-500) and 1000 ppm (SFO-1000) were added to preheated RBD sunflower oil. BHT at 200 ppm (SFO-BHT) served as standard besides a control (ctrl). Weight gain (WG), antioxidant activity index (AAI), peroxide value (PV), conjugated dienes (CD), conjugated trienes (CT) and thiobarbituric acid reactive substances (TBARS) were taken as the parameters for evaluation of stabilization efficacy of methanolic extracts of PP. Results from different parameters were in agreement with each other, suggesting higher efficiency of SFO-1000 followed by SFO-BHT, SFO-500, SFO-250 and Ctrl samples, respectively, with the exception of CD; which suggested higher efficiency of SFO-500 over SFO-BHT. Results reveal PP to be a potent antioxidant for the stabilization of sunflower oil. (C) 2007 Elsevier Ltd. All rights reserved.