The present paper reports the process variable influence on the losses/transfer of fatty compounds during the deacidification process of rice bran oil by liquid-liquid extraction. The influence of process variables such as free fatty acid concentration in the oil, water content in the ethanolic solvent and oil:solvent mass ratio, were analyzed using the response surface methodology, having the aim to maximize the transfer of free fatty acids and minimize the losses of neutral oil plus minor compounds. In addition, the UNIQUAC equation was used to predict the transfer/losses of fatty and nutraceutical compounds to the alcohol phase. Both methodologies, the mathematical model from non-linear multiple regression and the UNIQUAC model, presented good agreement with the experimental data. (c) 2005 Elsevier Ltd. All rights reserved.