Fatty Acid Distribution and Oxidative Stability of DHA/EPA-Enriched Structured Lipids From Virgin Coconut Oil

Abstract

Novel structured lipids (SLs) were successfully produced from virgin coconut oil (VCO) and docosahexaenoic acid (DHA) and/or eicosapentaenoic acid (EPA). Stereospecific analysis results indicated that both DHA and EPA were predominantly esterified at the sn-1 and sn-3 positions. For DHA-enriched VCO, caprylic acid (CyA, C8:0) was mainly esterified at the sn-2 position, while capric acid (CaA, C10:0) and lauric acid (LaA, C12:0) were primarily located at the sn-3 position. In EPA and DHA + EPA-enriched VCO, C8:0 and C10:0 were almost randomly distributed across all three positions, except for C12:0, which was mostly found at the sn-2 position. The oxidative stability results of the SLs showed higher levels of conjugated dienes (CD) and 2-thiobarbituric acid reactive substances (TBARS) after 12 days of storage. Furthermore, the primary volatile compounds identified in the SLs using headspace gas chromatography–mass spectrometry (HS GC–MS) included acetaldehyde, propanal, and 2-propenal (acrolein), which were absent in the unmodified oils. These results indicate that the modified oils exhibited a higher susceptibility to oxidation compared to their unmodified counterparts. Oils high in polyunsaturated fatty acids (PUFAs) require protection from oxidation to mitigate the detrimental effects of oxidation products and preserve their nutritional and health benefits.