Enzymatic Interesterification of Tripalmitin with Vegetable Oil Blends for Formulation of Caprine Milk Infant Formula Analogs

Abstract 

The structure of triacylglycerols in vegetable oil blends was enzymatically modified, and the blends were incorporated into skim caprine milk to produce goat milk-based infant formula analogs, homologous to human milk. A modified lipid containing palmitic, oleic, and linoleic acids, resembling the composition of human milk fat, was synthesized by enzymatic interesterification reactions between tripalmitin and a vegetable oil blend containing a 2.5:1.1:0.8 ratio of coconut, safflower, and soybean oils. A commercial sn-1,3-specific lipase obtained from Rhyzomucor miehei, Lipozyme RM IM, was used as the biocatalyst. The effects of substrate molar ratio and reaction time on the incorporation of palmitic, oleic, and linoleic acids at the sn-2 position of the triacylglycerols were investigated. The fatty acid composition and sn-2 position of the experimental formulas were analyzed using gas chromatography. Results showed that the highest incorporation of palmitic acid was obtained at 12h of incubation at 55°C with a substrate molar ratio of 1:0.4 of tripalmitin to vegetable oil blend. However, the modified milk interesterified for 12h at a 1:1 molar ratio had a greater resemblance to human milk compared with the other formulas. The level of oleic acid incorporation at the sn-2 position increased with the molar ratio of tripalmitin to vegetable oil blend. It was concluded that, unlike the original goat milk and other formulas, the formulated caprine milk with a molar ratio of 1:1 and a 12-h incubation was similar to the fatty acid composition of human milk.

Key words: enzymatic interesterification, tripalmitin, vegetable oil blend, caprine milk