The Preparation Of LML-Meddium-and Long-Chain Triglycrerides And Its Application Research In Shortening

Lately, obesity has become a globle problem, threatening to human health. High-caloriediet is the main reason causing obesity, in which fat is relevant to high calorie. To solve thisproblem, producing a fat substitute is most important.Presently, people have graduallydeveloped a series of fat substitutes, including the low calorie alternatives based oncarbohydrate and protein with low thermal stability and low calorie structure lipid which canprovide high nutritional value and avoid the accumulation of fat in the body. LML-meddium-and long-chain triacylglycerol(LML-MLCT) is a triacylglycerol with medium fatty acid atposition Sn-2and long fatty acid at positions Sn-1,3. This kind of srucuture lipid can notleading fat accumulation in case of its special metabolic way.In this study, we have investigated the preparation of LML-MLCT with lipase ascatalyst. Investited the stability in the transesterification of two lipase(Novozyme435lipaseand Lipozyme RM IM). The reactiontime,temperature,molar ration of the substrate,amount ofenzyme and the condition of vacuum were investigated. used central composite rotatabledesign(CCRD) to optimize the preparation of LML-MLCT with Lipozyme RM IM,includingthe reaction variables,including raction time, temperature and lipase dosage. The optimalreaction conditions were as follows: reaction temperature is51℃,reaction time is12.6h,thedosage of lipase is7.5wt%,and the resulting long-chain fatty acids incorpation rate is48.8%,acyl migration rate is6.9%under optimized conditions.In this study, the product purified by molecular distillation,deodorizer andbleaching.analyzing the composition of fatty acids and triacylglycerols,we find that thecontaining of LML-MLCT is73.17%with high transparency. the physc-chemical protertiesof acidity is0.03, and peroxide value is0.8, both of them are low than the correspondingindexs of commercially soybean oil, the color is slightly higher than commercially soybeanoil. So this kind of structure can be as a fat substitutes. According to the study ofantioxidants, we know that the joint usage of100mg/kg TBHQ and100mg/kg BHA canenhance oxidative stability compared200mg/kg THBQ and200mg/kg BHA alone.Last, we used LML-MLCT and PS to parepared base oil by mixing them. and six kind of base oils by mixing PS and LML-MLCT at differet rations are obtained According toanalyzing the solid fatty contents(SFC), we got the best rations is3:7. And in order to obtatinbetter shortening, we have analyzed the compositon of fatty acid,polymorphs, heating-andcrystallization-profiles. And then we choosed the best ratios of base oil to prepareshortening,and applied it in bread baking. Basing on GBT-20981-2007, we analyzed thesensory and physic-chemical properties of the baked bread. The result shows that the sensoryand physic-chemical index of bread baked by homemade shortening is under the standards ofGBT-20981-2007and also similar to the bread baked by commercial shortening.The resultshows that the LML-MLCT can be used in preparing shortening.