In the present study, soybean oil degumming in an oil/hexane miscella by ultrafiltration was investigated as a substitute for the conventional degumming process. A multi-channel ceramic membrane was used with 0.2 m(2) permeation area and a pore diameter of 0.01 mu m. The response surface methodology (RSM) was used with a complete 2(2) factorial design, considering the tangential velocity and transmembrane pressure as the independent variables. The phosphorous concentration in the permeate (degummed oil) and the permeate flux represented the dependent variables. The tangential velocity varied from 2.9 to 3.9 m s(-1) and the transmembrane pressure (TMP) from 1 to 2 bar. Up to 99.7% of the phospholipids were retained, resulting in a phosphorous concentration of 2.2 mg kg(-1). The permeate flux varied from 21.5 to 40.5 L m(-2) h(-1), with a mass reduction factor (MRF) of 3.2. The only variable shown to influence the process was the TMP. The lowest phosphorous content (2.2 mg kg(-1)) in the degummed oil and the highest permeate flux (40.5 kg m(2) h(-1)) were observed at 2 bar. (c) 2008 Elsevier Ltd. All rights reserved.