Production of omega-3 fatty acids acylglycerides by lipase-catalyzed glycerolysis of sardine oil in different reaction media

Abstract

Production of omega-3 polyunsaturated fatty acids (n-3 PUFA) concentrates is of great interest for both the pharmaceutical and the food industries. It is well known that the main n-3 PUFA, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, have beneficial effects on the prevention and reduction of cardiovascular and inflammatory diseases. However, not all the chemical forms of n-3 PUFA are equal. The bioavailability and susceptibility to oxidation of n-3 PUFA concentrates depend on their molecular structure. Monoacylglycerides and diacylglycerides (MAG and DAG) containing n-3 PUFA present good bioavailability and oxidation stability. Moreover, they present excellent emulsifying properties, being widely used in the food, cosmetic and pharmaceutical industries. Taking into account these considerations and the advantages of enzymatic technology in the formation of this kind of products, this Thesis is focused on the production of MAG rich in n-3 PUFA by a lipase-catalyzed glycerolysis reaction in different reaction systems. The main drawback of this process is the immiscibility of the substrates, therefore the main Además del estudio de la glicerolisis enzimática, otro objetivo de esta Tesis, fue la optimización del proceso de destilación molecular para fraccionar los productos de reacción y concentrar los MAG ricos en AGPI n-3. Se han evaluado diferentes temperaturas de evaporación para maximizar la recuperación de los MAG con alta pureza. También se ha evaluado en esta tesis la oxidación lípidica del aceite de sardina y de los productos de reacción. En este sentido se ha demostrado que las lipasas inmovilizadas son capaces de adsorber los productos de oxidación, tanto primarios como secundarios, formados durante la reacción de glicerolisis. (Psota et al. 2006). Excessive amounts of n-6 PUFA and hence a very high n-6/n-3 ratio of about around 15-20/1, is found in today's Western diets mostly derived from the high consumption of vegetable oils, as such or added in almost every commercially prepared food. A lower ratio of roughly four parts n-6 PUFA to one part n-3 PUFA is more desirable in reducing the risk of many of the chronic diseases of high prevalence in Western The most important natural sources of n-3 PUFA are marine organisms; this is fish, seafood and algae. EPA and DHA are synthetized by marine phytoplankton that feeds, directly or indirectly, these marine organisms. Herring, mackerel, salmon, sardines, tuna, and krill have a fairly good quantity of these compounds (Table I.1). In general, the greasier the fish the greater their concentration of EPA and DHA. However, some species of fish may contain significant levels of toxic compounds such as methylmercury, polychlorinated biphenyls (PCBs), dioxins, and other environmental contaminants. These substances are present at low levels in fresh waters and oceans, but they bioconcentrate in the aquatic food chain reaching higher values in old, large, predatory fish and marine mammals. Therefore, PCBs and methylmercury have long halflives in the body and ca...