The Research On Immobilized Lipase Preparation DAG Technology Of Rice Bran Oil

DAG is a lipid fatty acids by the hydroxy-substituted fatty acids in triglyceride. DAG has thefunction of reducing visceral fat and blocking fat. DAG also has the function of reducing bloodlipid by the research. Nowadays, DAG has been widely applauded as its use values.The experiment is to prepare DAG bye enzyme method. The immobilized lipase is as acatalyst. Take molecular distillation separation of DAG to obtain high purity diacylglycerol whenDAG were prepared. The repeated experiment use single factor test and four-factor quadricorthogonal regression test, which get a more accurate and reliable theoretical data andoptimization of the technological conditions. The main conclusions of this experiment are asfollows：(1)The study of immobilizing enzymes. The influences of amount of silylating reagents, themass ratio of diatomaceous earth particles and enzymes, temperature and time on the activity ofthe immobilized lipase were investigated. The optimum condition by response surfacemethod was as follows: the amount of silylating reagents were0.35%, the mass ratio ofdiatomaceous earth particles and enzymes was3.5:1, the temoerature was29℃,the time was4.5h. Under this conditions, the activity of the immobilized lipase was2206.67U/g. Confirmatorytest predicted the fractional error of the activity of the immobilized lipase was1.27%,whichverified the reliability of the response analysis model.(2)The study of preparing DAG by rice bran oil. In this experiment, the influences ofreaction temperature, reaction time, the amount of the immobilized lipase and the reactant ratioon DAG were investigated. The optimum condition of preparing DAG by rice bran oil was asfollows: the temperature was26℃, the time was10h, the amount of the immobilized lipasewas8.5%,the mass ratio of rice bran oil and dl-alpha-monoolein was14. Under thisconditions, the yield of DAG was58.31%.Confirmatory test predicted the fractional error was3.4(theoretical value was60.36%), which determined response analysis model was dependable.(3)The study on isolation and purification of DAG.In this experiment, the influences of feedrate, wiped Film rate, feed preheating temperature, distillation temperature on separation ofDAG were investigated. The conditions of molecule distillation were also optimized.The optimum condition was as follows: feed rate was0.4L/h, wiped Film rate was280r/min,feed preheating temperature was80℃, distillation temperaturewas200℃. Thecontent ofDAG was82.57±0.91(%)by verification test.(4)The study on testing index of products. The fluency indices of products were as follows:acid value was0.29mgKOH/g, saponification value was188.7mgKOH/g, unsaponifiable matter was3.06%, peroxide value was2.13mmol/kg, which correspond national targets for thesecondary rice bran oil.