A new mathematical approach to the bleaching process of edible oils

BACKGROUND As energy costs are constantly increasing, industries need to consider efficiency in all processes. Vegetable oils, which are among the daily staple foods, have large energy-consuming processes during refining. Bleaching, one of the most important of these processes, is a process in which energy is used abundantly. In this study, system parameters of bleaching earths were experimentally investigated for a factory that processes soybean and sunflower oil. RESULTS The bleaching earth used was characterized using X-ray diffraction and Brunauer-Emmett-Teller (BET) techniques, while the oils at the process outlet were analyzed according to ASTM standards. The amount of bleaching earth used and bleaching time were used as independent parameters, and color, acid and peroxide number values were determined. Furthermore, through the use of gathered experimental data, a model was developed to predict the color of products under different operating conditions. Two different approaches were used to estimate the color values of oils. According to the polynomial and thin plate spline approaches, 2-2.5 wt% bleaching earth and 60-80 min bleaching time were determined as optimum conditions. CONCLUSION It was determined that the ratio of bleaching earth and the bleaching time had a serious effect on the color, but their effects on acid and peroxide numbers were limited in comparison. There was no linear relationship between the bleaching time and the color change, and the excess time had a negative effect on the bleaching process depending on the amount of the bleaching earth. (c) 2020 Society of Chemical Industry