Both fresh and slightly oxidized sunflower oils, as models of omega-6 rich lipids, were submitted to in vitro gastrointestinal digestion and studied by 1H NMR and SPME-GC/MS. Changes in lipolysis degree, lipid composition and oxidative level were studied by 1H NMR. Three quantitative approaches were used and several equations were newly developed. In oxidized oil digestates slightly lower hydrolysis and a higher advance of oxidation took place during digestion. This latter was evidenced by a greater decrease of lipid unsaturation degree and enhanced generation of oxidation products (cis,trans-hydroperoxy-octadecadienoates, cis,trans- and trans,trans-hydroxy-octadecadienoates). For the first time, the generation of hydroxy-octadecadienoates during in vitro digestion is reported. Furthermore, SPME-GC/MS study of non-digested and digested samples headspaces confirmed that lipid oxidation occurred: abundances of volatile markers increased (including potentially toxic alpha,beta-unsaturated aldehydes), especially in oxidized oils digestates. Markers of Maillard-type and esterification reactions were also detected in the digestates.
Keywords: (2E,4E)-Nonadienal (PubChem CID: 5283339); (2E,4Z)-Decadienal (PubChem CID: 6427087); 13-Hydroperoxy-9Z,11E-octadecadienoic acid (PubChem CID: 5280720); 13-Hydroxy-9E,11E-octadecadienoic acid (PubChem CID: 5282948); 2-Pentyl-pyridine (PubChem CID: 16800); 9-Hydroperoxy-10E,12E-octadecadienoic acid (PubChem CID: 5282856); 9-Hydroperoxy-10E,12Z-octadecadienoic acid (PubChem CID: 9548877); 9-Hydroxy-10E,12E-octadecadienoic acid (PubChem CID: 5282945); 9-Hydroxy-10E,12Z-octadecadienoic acid (PubChem CID: 5312830); In vitro digestion; Linoleic acid (PubChem CID: 5280450); Lipolysis; Maillard volatiles; Omega-6 lipids; Oxidation; Sunflower oil.
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