Study On Glyceride Modification Technique Of Milk Fat

The proportion of triglycerides in milk fat is97%～98%. Excessive intake of triglycerides may lead to obesity and cardiovascular disease. The present experiment was designed to study a process for milk fat containing1,3-diacylglycerol(1,3-DG) by enzymatic glycerolysis, it was investigated the effect of modified milk on reducing lipid and obesity of mice, and a kind of analysis method for glyceride comprising1,3-DG was set up.1Determination of1,3-Diacylglycerol in milk fat of modifiedA qualitative and quantitative determination of the1,3-Diacylglycerol in milk fat has been established.Separation and qualitative identification by TLC showed that1,3-DG was detected in the sample. The quantitative analysis of1,3-DG was GPO-PAP.The RSD of the method was less than or equal to3.78%and the recovery was between86.73%～101.83%。 The methods is accurate, precise, rapid and suitable for the analysis of1,3-DG in milk fat in most laboratory with simple instruments.2Enzymatic glycerolysis of milk fat to produce1,3-DGEnzymatic glycerolysis of modified milk fat was studied with milk fat and glycerol as substrates in a solvent-free system. By the single-factor experiments, the best ranges of the major technological factors in the reaction have been identified as follows:the reaction time of2-24h, the enzyme additive amount of1%-8%, the reaction temperature of40℃-60℃, the water additive amount of0%-10%, the molar ratio of milk fat to glycerol of1:2-2:1.On the basis of the single-factor experimental results, effects of five factors on the yield of1,3-DG in the glycerolysis system were studied by the center combination experiment, the optimum conditions were obtained as follows:the reaction time of16.51h, the enzyme additive amount of6.41%, the reaction temperature of51.08℃, the water additive amount of4.35%, the molar ratio of milk fat to glycerol of1.33. Under those optimum conditions, the amount of1,3-DG reached37.74%～39.84%in the final product.Acid value and peroxide value of the modified milk fat conformed to ZBX14010-87, although the melting point, acid value, Saponification value, iodine value and peroxide value existed significant changes.3Effect of modified milk fat on obesity and lipid24male Kunming mice were randomly divided into three groups and respectively fed with normal diet,4%modified milk fat plus normal diet and4%milk fat plus normal diet for6weeks and the body weight, body fat and blood lipid were studied. The body weight, the weight growth, body fat contents, the serum TG, TC, LDL-C in mice of model group fed with modified milk fat plus normal diet were all significantly lower than other groups, While the serum HDL-C was significantly higher than normal diet group and no significantly difference between modified milk group and normal milk group. Therefore, the effect of modified milk on reducing lipid and obesity of male Kunming mice was showed.