The Enzymatic Preparation Technology Of Lard To Produce Human-milk Patterned Structured Triglyceride

Several commercially available infant formula and breast milk were collected, and the positional distribution and content of fatty acids in fat were determined. The result showed that:The fatty acids in infant formula were mainly oleic acid and palmitic acid (41.42% and 21.20% of the total fatty acids, respectively), while human milk fat contained 24.33% palmitic acid and 37.83% oleic acid, and oleic acid was mainly distributed in the Sn-1,3 position and palmitic acid in the Sn-2 position. Although the content of fatty acids in infant formula was similar to that of human milk fat, but the position distribution was opposite.To optimize the preparation technology of human-milk patterned structured triglyceride (HMPST). Lard, in which the total and Sn-2 positon content of palmtic acid are similar to that of human milk, was used as raw material to produce HMPST in which the total and Sn-2 positon content of palmtic acid are similar to the human milk, through Lipozyme RM IM catalized 1,3 specific interesterification reaction of lard and free fatty acids. Mono-factor experiment and response surface analysis were used to optimize process parameters. Results:The behavior of the reaction system was explained by the following quadratic equation between Sn-2 distribution of palmitic acid and the factors (temperature(A), reaction time(B), enzyme load(C), substrate ratio(D):Y=-2304.15+63.75A+129.27B+158.19C+45.85D-0.28AB-1.21 AC-0.12AD-6.02BC-0.36BD+3.62CD-0.50A2-24.64B2-52.00C2-2.05D2. Optimal conditions were determined as follows:reaction temperature 60.42℃; reaction time 1h; enzyme load 10.15%; substrate ratio (lard:free fatty acids)1:2.08. Under these conditions, the total and Sn-2 positon content of palmtic acid in HMPST are respectively 20.35% and 71.68% which is very close to that of human-milk. The optimized technology through response surface methodology is suitable for the production of HMPST from lard by interesterification with free fatty acids, the established model between Sn-2 distribution of palmitic acid and the factors is accurate and reliable.The effects of the urea adduction fractionation, solvent crystallization method and molecular distillation to refine human-milk patterned structured triglyceride were compared by experiments. The results showed that the urea adduction fractionation and the solvent crystallization method were not ideal with big loss of triglyceride, therefore, the molecular distillation mothod was chosen. The best separation effect was achived when distilled temperature was 210℃, feed speed was 15 mL/min on 0.06m2 evaporating surface, the acid value of the human milk patterned-structured triglyceride reduced to 2.6mg KOH/g and reached the requirements of the national standard.