A model study for decolorization reasons: beta-carotene removal and its kinetics and thermodynamics behaviors

Abstract

Decolorization is a significant process in the production of food products. Bleaching process for the removal of colored pigments such as beta-carotene from vegetable oils has been gaining interest by using many materials as adsorbents to purify the product from colored components. In this study, the adsorption mechanism of beta-carotene from chloroform was studied with different macroporous resins (Amberlite XAD-2, XAD-7, XAD-4 and XAD-16). The maximum adsorption capacity was determined to be 1570 mu g per gram Amberlite XAD-2. The performance of XAD-2 was followed by XAD-4 (1200 mu g/g), XAD-7 (1198 mu g/g), and XAD-16 (1002 mu g/g), respectively. The adsorption equilibrium, kinetics, and thermodynamics of the process were investigated depending on the selected resins. In this context, Langmuir, Freundlich, and Temkin isotherms were tested, where the current system has been found to have a physical adsorption based on the Temkin isotherm constant ( 0.72) has been more suitable to describe the kinetic data comparing to pseudo-second-order model, whereas all coefficients of variation (except for Amberlite XAD-16) of intraparticle diffusion model are close to 1 (> 0.95). It was also determined that the adsorption process did not occur spontaneously (Delta G > 0). It was endothermic (Delta H > 0) and progressed towards disorder (Delta S > 0).