Medium-and Long-chain Triglycerides Preparation And Application In Margarine

Medium-and long-chain triglyceride (MLCT), containing functional fatty acids such as medium-chain fatty acids (C8:0-C10:0, MCFA) and long chain fatty acids (≥C12:0, LCFA), is a new type of structured lipid. MLCT can replace animal fats or hydrogenated oils for low calorie and low-trans fatty acids magarine formulation. The research targeted for preparation of MLCT which was used in low-calorie margarine formulation by chemical and solvent-free lipase-catalyzed interesterification of fully hydrogenated high erucic acid rapeseed oil (HERO), medium-chain triglyceride (MCT), and palm oil (PO).Firstly, selected eleven kinds of HERO, MCT and PO mixtures (shortening HMP) were chemically interesterified for MLCT preparation under following conditions:90℃,60min,0.5wt.%sodium methoxide. Solid fat content (SFC), fatty acid composition (FAC), MLCT content, melting point and thermal properties of interesterified producats were investigated, and the results suggested that:HERO:MCT:PO=1:1:4(HMP-1) had higher contents unsaturated fatty acids, containing62%MLCT contents after interesterification, lower melting point, fine crystallization and melting characteristics after modifying, and was selected for application testing,Secondly,10kg MLCT oil was prepared according to HMP-1ratio. The parameters of refined MLCT product such as SFC, hardness, penetration, oxidation stability, whipping, anti-permeability were discussed. The results suggested that the product was suitable for the general sandwich margarine in terms of good spreadability and plastic range, hardness, penetration, whipping, better anti-oxidation and anti-permeability. Besides, the MLCT can also maintain good texture and appearance of margarine food at the room temperature.Finally, MLCT was synthesized by Lipozyme TL IM-catalyzed using HMP-1as substract. Single factor experimental results suggest that the equilibrium conditions of Lipozyme TL IM-catalyzed reaction were:70℃for rection temperature,5h for reaction time,5wt%for enzyme loading. The free fatty acid contents and acyl migration in the reaction system increased significantly along with the increasing of temperature, reaction time and enzyme concentration. Response surface methodology (RSM) was applied to model and optimize the reaction temperature, time and enzyme loading on the three critical SFCs(10℃,20℃and35℃, respectively, expressed as SFC-1, SFC-2and SFC-3) effects.The results suggested that the temperature, time and enyme loading were significant factors. The optimal lipase-catalyzed conditions were:75℃for reaction temperature,5h for reaction time, and5wt%for enzyme loading.