Kyselka, Jan; Cihelkova, Klara; Lopes-Lutz, Daise; Chudoba, Josef; Vachalova, Tereza; Alishevich, Katsiaryna; Hradkova, Iveta; Bercikova, Marketa; Mikolaskova, Monika; Filip, Vladimir published the artcile< Mechanism Controlling High-Temperature Degradation of Sunflower Oil Triacylglycerols in the Absence of Oxygen>, Electric Literature of 112-63-0, the main research area is sunflower oil triacylglycerol temperature degradation oxygen absence.
The aim of the present study is to describe the mechanism controlling heat-induced formation of sunflower oil triacylglycerol and fatty acid Me ester oligomers. The unique combination of high-performance size-exclusion chromatog. with hyphenated electrospray ionization mass spectrometry (MS), atm. pressure chem. ionization-MS, and high-temperature gas chromatog.-MS techniques allows differentiating between radical coupling species and Diels-Alder cycloadducts. Targeted anal. of thermally degraded sunflower oils confirms the exact structures of various acyclic oligomers accompanied by less-abundant products of pericyclic transformations. A series of model experiments simulate the impact of dienophile nature on the course of Diels-Alder reactions. Thus, α-tocopherylquinone, δ-tocopherylquinone, and methyl-(E)-11-oxoundec-9-enoate are synthesized as naturally occurring dienophiles bearing electron-withdrawing groups. The geometry of poor dienophiles does not affect concerted cyclization, while the structure of electron deficient dienophiles can overcome low reactivity. In the absence of oxygen, heat-induced degradation of polyunsaturated triacylglycerols proceed predominantly via a radical pathway, whereas concerted reactions represent minor mechanisms. Sunflower oil triacylglycerol mols. in the system without propagation stage can be effectively protected by natural and/or synthetic antioxidants. Application of chelates is also recommended. However, antioxidant-derived quinones, such as α-tocopherylquinone, can enter the Diels-Alder reaction even more easily than dienophiles without electron-withdrawing groups. Unsaturated core aldehydes possess the same reactivity. Examination of the mechanism controlling high-temperature degradation of triacylglycerols is especially important for processing engineers in edible oil refineries and food technologists. New perspective may help them to minimize undesirable changes in polyunsaturated species.
European Journal of Lipid Science and Technology published new progress about Antioxidants. 112-63-0 belongs to class esters-buliding-blocks, and the molecular formula is C19H34O2, Electric Literature of 112-63-0.
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