Modeling of the soybean oil bleaching and optimization of its conditions in the refining process for environmental interest

Abstract

In this work, we propose mathematical models describing the soybean oil bleaching process as a function of its parameters (temperature: 80 – 120 °C, clay dosage: 0.25 – 2 %, contact time: 10 – 30 min). The crude soybean oil visible spectrum shows three values of maximum wavelength (λmax). A value at 426 nm corresponding to the chlorophyll-a, the values at 451 and at 479 nm were assigned to β-carotene pigment. The models were developed using multiple linear regression analysis (MLRA) and were performed with Matlab programming language. The input variables are the temperature (X1), the clay dosage (X2) and the contact time (X3). The output parameter is the bleaching capacity (Y in % uptake). Statistical analysis methods were used to analyze and to confirm the reliability of the selected models. The optimal bleaching conditions for the soybean oil were: temperature 100 °C; clay dosage 2 % w/w and contact time 30 min. The highest bleaching capacity was found to be 81.04 % at 426 nm, 90.60 % at 451 nm and 93.66 % at 479 nm. The developed models allowed predicting the bleaching capacity representing the removal of the β-carotene and chlorophyll-a pigments present in the crude soybean oil at each λmax. Also they allowed a better control of the most influencing parameters on the bleaching step and contribute to the optimization of the spent bleaching clay rejects by optimizing the amount of bleaching clay used in the refining process; consequently, to reduce risks of pollution.

Decolorization of soybean oil by acid‐activated Ca‐Bentonite (EL Gnater, Central Tunisia)

“…This indicates the release of Al 3+ , Mg 2+ and Fe 3+ cations from the octahedral sheets. The obtained results accord well with those in the previous studies 27–47 and confirm the chemical found analyses.…”

“…31 Soybean oil contains colorants, such as chlorophyll, carotenoids and other products whose formulas contain a very large number of double bonds, thus giving the oil a yellowish, reddish color. 32…”

Structural and Surface Modification of Oxalic-Acid-Activated Bentonites in Various Acid Concentrations for Bleaching Earth Synthesis—A Comparative Study

“…All the colour values fall within the range of specifications for bleached soybean oil (<5 for red and <50 for yellow [41]) after bleaching with oxalic-acid-activated bentonites. Unlike what occurs with chlorophyll, the removal of colour from the oil does not seem to be dependent on pore diameter.…”

Functionality and mechanistic parametric study of the potential of waste plantain peels and commercial bentonite for soybean oil refining

“…The pseudo-second-order kinetic model investigation of the bleaching process can be expressed as following Eq. 5 4,5,28 :…”

“…where k 2 (gg −1 min −1 ) is the equilibrium rate constant of pseudo-second-order adsorption 4,28 . The slope of the plot of t/q t versus t was used to determine qe and then from the intercept, k 2 was calculated.…”