Nowadays it is known that excesses of either n-6 or n-3 PUFAs show immunosuppressive effects, and that maintenance of the immune response can be verified by administering LEs with n-6/n-3 FA ratios between 2:1 and 4:1 (Fan et al.,

2003 and Palombo et al., 1999). Soybean oil-based LEs show an n-6/n-3 FA ratio of about 7:1 (Horie, Torrinhas, Nardi, Cilengitide in vivo Waitzberg, & Falcão, 2007). SLs show metabolic advantages not provided by physical mixtures of different types of oil. They contain medium- and long-chain FAs on the same glycerol backbone, in contrast with the currently available ELs, which are a physical mixture of separate medium- and long-chain TAGs. One potential advantage of SLs is that they offer a broad choice of FAs in the composition of the TAGs. For example, soybean oil can be used to provide n-6 essential FAs, and FAs from fish oil can display anti-inflammatory effects and contribute to the structure of the central nervous system via their n-3 PUFAs. Due to its high concentration of eicosapentaenoic acid (EPA, C20:5, n-3) and docosahexaenoic acid (DHA, C22:6, n-3), fish oil has been shown to have anti-inflammatory potential by interfering with the arachidonic acid pathway and producing the anti-inflammatory eicosanoids prostaglandin E3, leukotriene B5 and thromboxane A3 (Dudrick, Wilmore, Vars, & Rhoads, 1969). PUFAs from the n-3 family also

play a primary role in brain and retina development and DHA has a special role in visual and cerebral function selleck chemical in premature children, probably extending throughout their entire childhood (Innis, 2000), being incorporated mafosfamide into the central nervous system during development of the infant brain (Hartvigsen, Mu, & Hoy, 2003). Many studies have investigated the lipase-catalysed interesterification for the production of n-3 PUFA-enriched fats (Fajardo et al., 2003 and Osório et al., 2001) and a number of procedures patented (Macrae and How, 1983, Matsuo et al., 1979 and Nakamura et al., 1987). Most

of these were kinetic studies on model reactions for acidolysis on a laboratory scale in the presence of organic solvents (Ghazali et al., 1995, Senanayake et al., 2002a, Soumanou et al., 1997 and Senanayake and Shahidi, 2002b). However, in these systems the recovery of the modified TAGs posed a separation problem. The aim of the present study was to model the production of SLs with n-6/n-3 ratios adequate for parenteral nutrition via response surface methodology (RSM), using lipase-catalysed acidolysis in solvent-free media. The process consists of a set of mathematical and statistical methods developed for modelling phenomena and finding combinations of a number of experimental factor variables that will lead to optimum responses. With RSM, several variables are tested simultaneously with a minimum number of trials, according to special experimental designs based on factorial designs (Box et al.