Kinetic Study of Adsorption of Pigments and Oxidation Products in the Bleaching of Rice Bran Oil

Abstract

Abstract In this study, different concentrations and types of adsorbents (activated earth, chitin and chitosan) were tested for adsorption of carotenoids, chlorophylls and peroxides in the bleaching of rice bran oil (RBO). The bleaching kinetics showed that using 1 % (w/w) of activated earth for 20 min, there was a suitable reduction in peroxide and pigment contents. The bleaching with 2 % (w/w) of biopolymeric adsorbents promoted to a decrease of around 40 % in the peroxide value. The increased concentration of activated earth led to an increase in the adsorption rate constant, indicating more speed in the bleaching process. The pseudo-second-order model showed best fit to the experimental data in the oil bleaching onto activated earth; however, the pseudo-first-order model was more appropriate to describe the kinetic behavior of adsorption onto chitin and chitosan. The biopolymeric adsorbent has shown to be a potential source for adsorption of metal ions in RBO.