PL
Prowadzono proces enzymatycznego przeestryfikowania mieszaniny oleju rzepakowego i łoju wołowego (4:6 w/w). Katalizatorami reakcji były immobilizowane enzymy lipolityczne produkowane przez duńską firmą Novo Nordisk: Lipozyme RM IM, Lipozyme TL IM oraz Novozym 435. Produkty reakcji rozdzielano przy pomocy chromatografii kolumnowej. Triacyloglicerole (TAG) eluowano mieszaniną eteru naftowego i eteru dietylowego (87:13). W otrzymanych produktach oraz w wyizolowanych z nich TAG oznaczano temperaturą topnienia, zawartość fazy stałej oraz stabilność oksydatywną. Określano również strukturą otrzymanych TAG, stosując metodą enzymatycznej hydrolizy. Stwierdzono, że we wszystkich produktach przeestryfikowania oraz w TAG wyizolowanych z tych produktów nastąpił spadek zawartości fazy stałej i temperatury topnienia w porównaniu z mieszaniną wyjściową, natomiast stabilność oksydatywna otrzymanych produktów uległa pogorszeniu.
EN
Enzymatic interesterification was carried out using a mixture of rapeseed oil and tallow (4:6, w/w). The reactions were catalyzed by immobilized lipolytic enzymes (Novo Nordisk, Denmark): Lipozyme RM IM (from Rhizomucor miehe), Lipozyme TL IM (from Thermomyces lanuginosus), and Novozym 435 (from Candida Antarctica). The reactions were conducted under the following conditions: reaction time, 3 h; temperature, 65°C, quantity of enzyme preparation, 8%. The reaction products, mainly triacylglycerols (TAG) and a small amount of free fatty acids (FFA) as well as di- and monoacylglycerols (DAG + MAG), were separated by column chromatography. The TAGs were eluated using a mixture of petroleum ether and diethyl ether (87:13). Then the weight of the obtained TAGs was determined. The most TAG (-94%) were in products obtained using Novozym 435 catalyst, whereas products of interesterification with Lipozyme RM IM and Lipozyme TL IM had 86.8% and 81.1% of TAG, respectively. Melting temperature (using the open capillary method), the solid content as a function of temperature (NMR method), and the oxidative stability (DSC method) of the products and the isolated TAG were determined. Also the structures of the obtained TAGs were determined using enzymatic hydrolysis method in the presence of sn-1,3 specific pancreas lipase. The results showed that there was a decrease in the solid content and melting temperature of the interesterification products as well as of the TAGs isolated from these product in comparison with the initial blends. The smallest decrease was observed for TAGs isolated from interesterification products with Novozym 435 catalyst. However, the largest decease in the solid content and melting temperature was observed for TAGs obtained from interesterification products using Lipozyme RM IM and Lipozyme TL IM. Both curves of solid contents as a function of temperature had a similar course. Analyzing the structures of the TAGs, confirmed that in the presence of both Lipozyme RM IM and Lipozyme TL IM the fatty acid changes in the TAG molecules occurred mainly in the sn-1,3 external position of the TAG ester bonds; insignificant changes occurred in sn-3 position. The presence of DAG + MAG in the products further caused a decrease in the solid content and melting temperature. Also, interesterification caused a decrease in the oxidative stability of the products in comparison with the initial blends.