Docosahexaenoic acid in regio- and enantiopure triacylglycerols : Oxidative stability and influence of chiral antioxidant

Funding Information: The authors would like to thank Dr. Jukka-Pekka Suomela for the guidance of using UHPLC -QTOF and Linda Intonen for assistance with part of the practical work related to fatty acid analysis. Personal financial grant to Annelie Damerau from the Finnish Cultural Foundation is acknowledged. Further, personal financial grants to Eija Ahonen from Niemi Foundation, the Finnish Cultural Foundation and the Finnish Food Research Foundation are acknowledged. This work entity was carried out as part of the Academy of Finland funded project “Omics of oxidation – Solutions for better quality of docosahexaenoic and eicosapentaenoic acids” (grant number 315274, PI Kaisa M. Linderborg). Publisher Copyright: © 2022 The Author(s)Docosahexaenoic acid (DHA) is essential for health but easily oxidized. Yet the influence of DHA's exact location (sn-1, sn-2, or sn-3) in triacylglycerols on oxidative stability is currently unknown. This is the first study comparing oxidative stability of DHA in regio- and enantiopure triacylglycerols with or without RRR-α-tocopherol. Headspace solid-phase micro-extraction with gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry, and nuclear magnetic resonance spectroscopy were applied. DHA in sn-2 was the most stable with or without added RRR-α-tocopherol resulting in differences in hydroperoxide formation. Without antioxidant, stability of DHA in sn-1 and sn-3 was mainly similar, with slight tendency towards better stability in sn-3. With RRR-α-tocopherol higher stability in sn-1 compared to sn-3 was observed. This points to diastereomeric interactions between RRR-α-tocopherol and DHA in sn-1. These results are highly relevant for enzymatic restructuring processes of DHA-rich fish or microalgae oil concentrates aimed for food supplements or food fortification.Peer reviewe