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Application of high‐resolution, two‐dimensional 1 H and 13 C nuclear magnetic resonance techniques to the characterization of lipid oxidation products in autoxidized linoleoyl/linolenoylglycerols
Author(s) -
Silwood Christopher J. L.,
Grootveld Martin
Publication year - 1999
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-999-0421-5
Subject(s) - chemistry , polyunsaturated fatty acid , heteronuclear molecule , adduct , conjugated system , nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , fatty acid , analytical chemistry (journal) , organic chemistry , physics , polymer
Subjection of polyunsaturated fatty acid (PUFA)‐rich culinary oils to standard frying episodes generates a range of lipid oxidation products (LOP), including saturated and α,β‐unsaturated aldehydes which arise from the thermally induced fragmentation of conjugated hydroperoxydiene precursors. Since such LOP are damaging to human health, we have employed high‐resolution, two‐dimensional 1 H‐ 1 H relayed coherence transfer, 1 H‐ 1 H total correlation, 1 H‐ 13 C heteronuclear multiple quantum correlation, and 1 H‐ 1 H J‐resolved nuclear magnetic resonance (NMR) spectroscopic techniques to further elucidate the molecular structures of these components present in (i) a model linoleoylglycerol compound (1,3‐dilinolein) allowed to autoxidize at ambient temperature and (ii) PUFA‐rich culinary oils subjected to repeated frying episodes. The above techniques readily facilitate the resolution of selected vinylic and aldehydic resonances of LOP which appear as complex overlapping patterns in conventional one‐dimensional spectra, particularly when employed in combination with solvent‐induced spectral shift modifications. Hence, much useful multi‐component information regarding the identity and/or classification of glycerol‐bound conjugated hydroperoxydiene and hydroxydiene adducts, and saturated and α,β‐unsaturated aldehydes, present in autoxidized PUFA matrices is provided by these NMR methods. Such molecular information is of much value to researchers investigating the deleterious health effects of LOP available in the diet.