High lauric human milk fat analog prepared from palm stearin and coconut oil by enzymatic interesterification

Abstract

In this study, an attempt to synthesize palm and coconut based Human Milk Fat analog (HMF analog) with high percentage of palmitic acid in the sn-2 position and high lauric acid in the sn-1,3 positions of the triglycerides was carried out. The first step was preparation of monoglycerides by hydrolysis of palm stearin, which is rich in palmitic and oleic acids in their sn-2, using porcine pancreatic lipase, which has specificity in sn-1,3. The 2-monoglycerides (2-MG) product were separated and purified by thin layer chromatography (TLC), and it was confirmed having 55.21% of palmitic acid and 35.26% of oleic acid. The second step was interesterification of the 2-MG from palm stearin with high lauric fatty acid methyl ester, previously obtained by methanolysis of coconut oil, to synthesize HMF analog using immobilized lipase from Rhizomucor miehei (lipozyme RM IM) as biocatalyst. Enzymatic interesterification reactions were held at various reaction temperatures (50, 55 and 60°C), reaction times (6, 12, 18 and24 h) and enzyme concentrations (2.5, 5.0, 7.5 and 10.0 wt% of total substrate). The interesterification condition was temperature of 50°C for 12 h of reaction time and enzyme concentration of 10.0% (w/w). The content of Medium Chain Fatty Acids (MCFA) in the HMF analog was 43.86% and the main constituent was lauric acid (39.37%), whereas the sn-2 position was dominated by palmitic acid (24.18%). Key words: Coconut oil, palm stearin, human milk fat analog, high lauric, enzymatic interesterification.