Enzymatic Incorporation Of Eicosapentaenoic Acid (Epa) and Docosahexaenoic Acid (Dha) Into Virgin Coconut Oil (Vco) and Medium-Chain Triacylglycerol (Mct) Oil and Oxidative Stability of The Resultant Structured Lipids

Lipase-catalyzed acidolysis or interesterification of virgin coconut oil (VCO) and medium-chain tricaylglycerol oil (MCT oil) with long-chain polyunsaturated fatty acids (PUFA), EPA and DHA, was studied using the 1,3 specific immobilized lipases from Thermomyces lanuginosus and Rhizomucor miehei (a species of fungus). Between the two enzymes tested, T. lanuginosus showed a higher incorporation of EPA or DHA into VCO or MCT oil. The effect of variation of reaction parameters such as time course, mole ratio of substrate and enzyme load were monitored for the most effective enzyme, ie. T. lanuginosus as the biocatalyst of choice. The incorporation of EPA, DHA, and EPA+DHA increased significantly with increasing time course from 12 to 48 h of incubation. The highest incorporation level of EPA, DHA or EPA+DHA occurred at 45°C for 36h with a mole ratio of 1:3 (oil: EPA or DHA) and 1:3:3 (oil: EPA+DHA). In the ethyl eicosapentaenoic ester (EEPA) as acyl donor, EPA incorporation in MCT oil and VCO were 76.97 and 69.88%, respectively. Using EPA as the acyl donor, EPA incorporation in MCT oil and VCO were 56.35 and 48.64%, respectively. Meanwhile, DHA as acyl donor resulted in DHA incorporation into MCT oil and VCO at 65.51 and 73.84%, respectively. The oxidative stability of enzymatically modified oils as well as their unmodified counterparts were accessed under Schaal-oven condition (autoxidation) at 60±2°C over a10-day period and fluorescent light condition (photooxidation) at 28.5±1°C over 72 h. The Conjugated dienes (CD) and 2-thiobarbutiric acid reaction substances (TBARS) were determined. Among the oils examined, the modified oils, as expected, had higher CD and TBARS values compared to those of their unmodified counterparts. The CD and TBARS values of modified oils were increased significantly from day 0 to day 10 of autoxidation and 0 h to 72 h of photooxidation.