Lipase-Catalyzed Acidolysis Of Lard To Produce Structured Lipids

There exist rich and inexpensive lard in China, but this resource has not got effective utilization. In order to improve the use and nutrient values, lipase catalyzed acidolysis to modify lard in nonhydrous medium was investigated. The aim is introducing new fatty acids with special function to the triacylglycerol from lard, lowering the melting point and calorie of lard, and endowing lard with new functions. This will make lard a new functional lipid beneficial to human health.A high performance liquid chromatography (HPLC) method for the determination of fatty acid composition and positional distribution from lard has been established. The analysis was carried out with a sn-1, 3 specific lipase to deacylate the fatty acid residues esterified at sn-1 and sn-3 positions of triacylglycerols, forming sn-2 monoglycerides and free fatty acids. After lipase action, it was possible to determine the fatty acid esterified at the sn-2 position by the substraction of the results of the sn-1, 3 analyses form an overall composition analysis based on complete saponification of the original sample. The free fatty acid mixtures were converted to phenacyl esters via 2-bromoacetophenone and analyzed on an Agilent 1100 series high performance liquid chromatography (HPLC). The results showed HPLC was work well in analyzing the fatty acid composition and positional distribution of fatty acids on triacylrglycerol from lard. This method was comparable to traditional Gas Chromatography.Lipase-catalyzed acdiolysis of lard with caprylic acid in micro-water solvent system and solvent-free system was investigated. It was found that of the five lipases tested in the initial screening, immobilized lipase Lipozyme TL IM was the best catalyst. The effect of lipase dosage, reaction time, reaction temperature, substrates mole ratio, content of water addition as well as stability of lipase was further studied. The results showed that the optimum conditions for caprylic acid incorporation in above two systems was as follows: immobilized lipase Lipozyme TL IM as catalyst ,10 ~ 15 % of lipase dosage, 1:2 of mole ratio of lard to caprylic acid, at 55℃ for 24 h and 32.4±2.60 mol% in no solvent system, 20 % of lipase dosage, 1:2 of mole ratio of lard to caprylic acid, at 50 ~ 60℃ for 24 h, and 0 ~ 10 % ( for hexane system) or 0 ~ 2.5 % (for no solvent system) of added water. Under...