Docosahexaenoic Acid is More Stable to Oxidation when Located at the sn-2 Position of Triacylglycerol Compared to sn-1(3)


Regio-isomeric effects on the oxidative stability of triacylglycerols (TAG) containing docosahexaenoic acid (DHA) were investigated using two pairs of regio-isomerically pure TAG, namely 1,3-dihexadecanoyl-2-(4,7,10,13,16,19-docosahexaenoyl)glycerol (PDP)/1,2-dihexadecanoyl-3-(4,7,10,13,16,19-docosahexaenoyl)glycerol (PPD) and 1,3-dioctadecenoyl-2-(4,7,10,13,16,19-docosahexaenoyl)glycerol (ODO)/1,2-dioctadecenoyl-3-(4,7,10,13,16,19-docosahexaenoyl)glycerol (OOD) where P, O, and D represent palmitic acid, oleic acid, and DHA respectively. Each pair of regio-isomers was subjected to accelerated auto-oxidation (at 40 or 50 °C inside a dark oven). In each case, the TAG oxidized more slowly when DHA was located at the sn-2 position (PDP and ODO) compared to the sn-1(3) position (PPD and OOD), as evidenced by slower development of peroxide value, slower depletion of DHA, and slower generation of secondary oxidation products propanal and trans, trans-2,4-heptadienal. The positional effect on auto-oxidation was more pronounced when DHA occurred in combination with oleic acid than with palmitic acid.

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Correspondence to Chakra Wijesundera.

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Wijesundera, C., Ceccato, C., Watkins, P. et al. Docosahexaenoic Acid is More Stable to Oxidation when Located at the sn-2 Position of Triacylglycerol Compared to sn-1(3). J Am Oil Chem Soc 85, 543–548 (2008).

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  • Auto-oxidation
  • Docosahexaenoic acid
  • Omega-3 fatty acid
  • Oxidative stability
  • Regio-isomer
  • Triacylglycerol