Utilization of potato peels extract as a natural antioxidant in soy bean oil

Potato peel extract, as natural antioxidant was evaluated during 60 days storage of refined soy bean oil at 25 and 45degreesC. Free fatty acids (FFA), peroxide values (POV) and iodine values (IV) were used as a criteria to assess the antioxidant activity of potato peel extract. Different organic solvents, including ethanol, methanol, acetone, hexane, petroleum ether and diethyl ether, were used to prepare extracts of potato peels. Maximum amount of extract (21%) was obtained with petroleum ether, followed by diethyl ether (15.25%) and methanol (14.75%). After 60 days' storage at 45degreesC, soy bean oil, containing 1600 and 2400 ppm of petroleum ether extract of potato peels, showed lower values of FFA (0.120, 0.109%) and POVs (10.0, 9.0 meq/kg) than the control samples (FFA 0.320%, POV 59 meq/kg). Soy bean oil containing 200 ppm of BHA and BHT showed FFA values of 0.102 and 0.078%, whereas POVs were 8.0 and 6.0 meq/kg, respectively, after 60 days, storage at 45degreesC. Similarly, after 60 days, storage at 45degreesC, iodine values of soy bean oil containing 1600 and 2400 ppm of potato peel extract were 71 and 77, respectively, which were higher than the control samples of oil (58). However, iodine values for soy bean oil treated with 200 ppm of BHA and BHT were 80 and 84, respectively, after 60 days' storage at 45 C. These results illustrate that potato peel extract, at various concentrations exhibited very strong antioxidant activity which was almost equal to synthetic antioxidants (BHA & BHT). Therefore, potato peel extract in oils, fats and other food products can safely be used as natural antioxidant to suppress lipid oxidation. (C) 2003 Elsevier Ltd. All rights reserved.