Effect of Roasted Sesame Oil on Qualitative Propert ies of Frying Oil during Deep-Fat Frying

Abstract

In this study, sesame seed was firstly roasted at 2 16.8°C for 19.3 minutes and its oil was then extracted. Commercial Frying Oil (CFO) was ble nded by 10, 20, and 30% Roasted Sesame Oil (RSO) and used in deep-fat frying to pre pare potato chips. The process was performed daily at 180 o C for 1 hour, in five consecutive days. Frying perf ormance of the oils was evaluated by the measurement of parameters such as peroxide value, Oxidative Stability Index (OSI), Total Polar Compounds (TPC) and fatty acids profile. The results showed that roasting had a great positive influence on phenolic compounds content (21 times) and oxidative stability (3.6 times) of sesam e oil. During frying, the level of TPC increased significantly as an increasing rate of 27 , 22, 21, 23.2, and 29% was obtained for RSO-10%, RSO-20%, RSO-30%, CFO-Tert-ButylHydroQuino ne (TBHQ), and CFO, respectively. The OSI significantly decreased and, in the fifth day of f rying, CFO-TBHQ had the highest OSI of 10.6 hours followed by RSO-30% (8 hours). By in crement in RSO concentration, the antioxidant capacity of frying o ils was elevated, although commercial frying oil containing TBHQ exhibited higher activit y than RSO-30%. Keywords: Antioxidant, OSI, Phenolic compounds, Polar compou nds, Tert-butylhydroquinone.