Changes in Quality Characteristics of Different Deep Frying Fats During Frying and Regeneration Potentials of Different Adsorbents in Wasted Frying Oils

Abstract

Regeneration potentials of synthetic magnesium silicate, acid activated bleaching earth and natural bleaching earth for the fried soybean oil after progressive laboratory scale frying. The wasted palm olein and sunflower oils which were obtained from two different restaurants were investigated. As indication for development of deterioration reactions in oil during frying and regeneration potentials of so-called adsorbents, free fatty acid content (FFA), total polar material (TPM), dielectric constant (DC) and color measurement values (L, a and b) were measured. According to the results, synthetic magnesium silicate (SMS), acid activated bleaching earth (ABE) and natural bleaching earth (NBE) have different adsorbent characteristics that were significantly affected by the origin, physical and chemical properties and production method of that adsorbent. Laboratory scale frying operations were significantly increased FFA, TPM and DC as a result of thermal oxidation reaction. The usage of SMS in the wasted soybean oil reduced FFA content, TPM and DC values while lighten the color. Nevertheless, the reductions of these values were much more evident for in wasted sunflower oil from Restaurant A (WA) and wasted palm olein from Restaurant B (WB) when compared to wasted oil obtained from laboratory scale frying operations. All values were reduced with the use of adsorbents while L values of WB is increased with adsorbent usage. Generally SMS showed a higher reducing potential on FFA content, TPM and DC values which are considered as deterioration indices of oil quality during frying operation.