Response surface modelling of the production of omega-3 polyunsaturated fatty acids-enriched fats by a commercial immobilized lipase

The aim of this study was to model the production of fats, enriched with om ega -3 polyunsaturated fatty acids (omega -3 PUFA) for nutraceutical purpos es, via the response surface methodology. These fats were obtained by trans esterification of palm oil stearin (POS) with a concentrate (EPAX 2050TG) o f triglycerides enriched with omega -3 PUFA and soybean oil, catalysed by a commercial immobilized Candida antarctica lipase ("Novozym 435"). The initial water activity (a(w)) of the biocatalyst, POS and EPAX 2050TG c oncentrations, time and temperature showed a significant effect on the tran sesterification reaction, as well as on the competing reactions of hydrolys is and lipid oxidation. Depending on the factors included, the transesterif ication reaction was described either by first- or second-order models. The production of free fatty acids, which is ascribed both to the hydrolyti c reaction and the mechanism of lipase-catalysed transesterification, showe d a second-order dependence on the initial a, of the biocatalyst. (C) 2001 Elsevier Science B.V. All rights reserved.