Optimisation of enzymatic esterification of soybean oil deodoriser distillate

The enzymatic esterification of free fatty acids from soybean oil deodoriser distillate with ethanol, catalysed by immobilised fungal lipase, was studied. The extent of conversion of free fatty acids to ethyl esters was optimised using a response surface methodology obtained through a second-order factorial experimental design. The variables studied were reaction temperature (30-70 degreesC), enzyme concentration (7-23%) and ethanol/free fatty acid molar ratio (0.3-3.7:1). The optimal reaction conditions achieved were temperature from 46.4 to 53.6 degreesC, enzyme concentration from 13.6 to 16.5% and ethanol/free fatty acid molar ratio from 1.7 to 2.3:1, with conversions above 88%. No significant tocopherol losses were observed during the process. In conclusion, enzymatic fatty acid esterification was shown to be a technically viable process. (C) 2001 Society of Chemical Industry.81121193119