Enzymatic Esterification of Fatty Acid Mixtures from Milk Fat and Anhydrous Milk Fat with Canola Oil in Supercritical Carbon Dioxide

The ester ethyl oleate was synthesized from oleic acid and ethanol by using the lipase, Candida cylindracea, immobilized on Celite 545 and in supercritical carbon dioxide (SC‐CO2) as the solvent. The enzymatic esterification reaction is much faster in SC‐CO2 than in organic solvents. This technique was then applied to the hydrolysis products of milk fat to determine the feasibility of using it as a process to enhance flavor. Gas chromatographic (GC) analysis of the ethyl esters showed that short‐chain fatty acids (C4‐C8) esterify more completely than long‐chain fatty acids (C16‐C18). The technique was then applied to interesterify a mixture of triglycerides from canola oil (CNO) and anhydrous milk fat (AMF). The starting mixture contained predominantly C52‐C56 triglycerides from the CNO and C32‐C38 triglycerides from the AMF. The product exhibited predominantly the C42‐C50 and C54 triglycerides.