Preservation of minor components and deacidification of rice bran oil using strong anionic resin

Abstract

Rice bran oil presents high levels of tocopherols/tocotrienols and gamma-oryzanol, which are recognized for their nutraceutical effects. However, these minor compounds can be sensitive to the traditional refining processes, which necessarily include a deacidification step. Therefore, alternative processes are required to preserve these nutraceuticals in the deacidified oil. This study aimed to investigate an alternative deacidification process based on strongly basic anion exchange resin. Aiming to evaluate the adsorption process efficiencies, breakthrough curves were obtained for systems containing Amberlyst A26 OH and a miscella composed of 50% by mass of degummed rice bran oil, with natural acidity (9.74% by mass), and n-propanol. The resin showed a high capacity for removing free fatty acids (90%–99% removal efficiency), and the adsorption process yielded deacidified rice bran oil with a reduced phosphorus content (2.2 mg/kg), preserving 83% of the gamma-oryzanol and 100% of the tocopherols/tocotrienols. Practical applications A softer deacidification process than traditional methods is proposed in this study. It permits to remove free fatty acids, preserving minor compounds of interest, notably nutraceutical compounds in the deacidified oil. The use of anion exchange resins in this step of refining process minimizes the effluent generation when compared to chemical refining, besides could be accomplished under milder conditions of pressure and temperature than physical refining.