Laboratory of Biophysics, Wageningen University and Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Food Chem. 2023 Feb 15;402:134417. doi: 10.1016/j.foodchem.2022.134417. Epub 2022 Oct 1.
In mayonnaise, lipid and protein oxidation are closely related and the interplay between them is critical for understanding the chemical shelf-life stability of mayonnaise. This is in particular the case for comprehending the role of low-density lipoprotein (LDL) particles acting as a main emulsifier. Here, we monitored oxidation and the concomitant aggregation of LDLs by bright-field light microscopy and cryogenic transmission electron microscopy. We further probed the formation of protein radicals and protein oxidation by imaging the accumulation of a water-soluble fluorescent spin trap and protein autofluorescence. The effect of variation of pH and addition of EDTA on the accumulation of the spin trap validated that protein radicals were induced by lipid radicals. Our data suggests two main pathways of oxidative protein radical formation in LDL particles: (1) at the droplet interface, induced by lipid free radicals formed in oil droplets, and (2) in the continuous phase induced by an independent LDL-specific mechanism.
在蛋黄酱中，脂质和蛋白质的氧化密切相关，它们之间的相互作用对于理解蛋黄酱的化学货架期稳定性至关重要。对于理解作为主要乳化剂的低密度脂蛋白 (LDL) 颗粒的作用尤其如此。在这里，我们通过明场光显微镜和低温透射电子显微镜监测 LDL 的氧化和伴随的聚集。我们进一步通过成像水溶性荧光自旋捕获剂和蛋白质自体荧光的积累来探测蛋白质自由基和蛋白质氧化的形成。pH 值变化和 EDTA 添加对自旋捕获剂积累的影响验证了蛋白质自由基是由脂质自由基诱导产生的。我们的数据表明 LDL 颗粒中氧化蛋白质自由基形成的两个主要途径：(1) 在液滴界面处，由油滴中形成的脂质自由基诱导；(2) 在连续相中由 LDL 特有的独立机制诱导。
