Present research studies the effects of bleaching and deodorizing parameters on physicochemical properties consisting of fatty acid compositions (FAC), iodine value (IV), saponification value (SV), refract index (RI) and also oxidative stability evaluation containing peroxide value (PV), acid value (AV), oxidative stability index (Rancimat test) and Anisidine value. The percentage of bleaching clay 0.8, 1.0 and 1.2 (w/w), the temperature of 200 and 220 (°C) and the pressure of 2 and 3 (mbar) were used to refine frying oil. The results indicated the bleaching and deodorizing process had no significant effect on the FAC, IV, SV and the RI of frying oils. Investigation on oxidative stability distinguished the increase of bleaching clay led to more degradation of fatty acid peroxides; thus decreasing PV. In spite of obtained result for PV, the Anisidine value increased at the end of bleaching step. The secondary oxidation products were removed more at higher temperature. Rancimat test presented a decrease in the samples exposed by high temperature and pressure due to more remove of phenolic compound.

Keywords: Frying oil, bleaching condition, deodorizing condition, physicochemical properties, oxidative stability evaluation

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