Abstract
Abstract Bleaching is an important part of the oil refining process, in which pigments, impurities, traces of metals, and oxidative-molecular components of oils are removed. In this regard, the optimization of bleaching conditions can be effective to increase oil quality. In this study, de-gummed and neutralized sunflower oil was bleached at 80, 90, 100, 110, and 120 °C for 15, 25, 35, 45, and 55 min by acid-activated bleaching clay with the concentrations of 0.4, 0.6, 0.8, 1, and 1.2% under laboratory conditions. At that point, peroxide, anisidine, plus Totox values, free fatty acid content, Rancimat, and specific UV absorption at 232 and 270 nm were analyzed via the RSM method. The model optimization using the RSM method revealed that the optimal conditions were 37.31 min, temperature 92.7 °C, and clay concentration 1.18%; this circumstance can meet 86.7% of the expectations as could be met for reducing the factors effective for oxidization during bleaching.
Highlights
Crude vegetable oils contain impurities that, in addition to creating unpleasant flavors and tastes, can have a harmful effect on consumer health
Due to the simultaneous effect of temperature, time, and concentration of the bleaching clay on the peroxide value, it was determined that each factor, in addition to the independent effect, could interact with other factors
According to the analysis of variance table (Table 2) and Figure 2, it might be concluded that the concentration of the bleaching clay had the greatest effect on the reduction of the peroxide value and the temperature was the important factor; this was consistent with the results obtained by Skevin et al (2012)
Summary
Crude vegetable oils contain impurities that, in addition to creating unpleasant flavors and tastes, can have a harmful effect on consumer health. Oil refining is necessary to remove undesirable compounds such as oxidation products and improve the quality (Didi et al, 2007). Auto-oxidation is a reaction with molecular oxygen through an autocatalytic mechanism, which is the main reaction involved in the oxidative degradation of fats (Fennema, 1996). This mechanism consists of starting, propagating, and ending reactions that can be initiated periodically. Peroxy radicals respond with an unsaturated fat molecule, forming a hydroperoxide and a new unstable fat radical
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
