Food Chemistry, Department of Food Science, Faculty of Life Sciences, University of Copenhagen, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark.
J Agric Food Chem. 2011 Sep 28;59(18):10329-35. doi: 10.1021/jf202268q. Epub 2011 Sep 6.
The interaction between phenolic compounds and protein thiols was investigated in minced beef with or without 500 ppm 4-methylcatechol (4-MC) that had been stored under oxygen or argon for 7 days (4 °C). Myofibrillar protein isolates were extracted, and the oxidative stability evaluated by the protein radical intensity measured by ESR spectroscopy was found to be improved by 4-MC as well as by storage without oxygen. Significant loss of thiols was found in samples stored under oxygen compared to argon, whereas an additional loss was found in samples with added 4-MC stored under oxygen. In beef with added 4-MC, LC-MS analysis showed formation of thiol-quinone adducts, which may explain the observed additional loss of thiols. Although storage without oxygen inhibited protein cross-link formation as evaluated by SDS-PAGE, both in presence and in the absence of 4-MC, no inhibitory effect of 4-MC was found on the formation of protein disulfide cross-links in beef stored under oxygen.
研究了在有氧或无氧（4°C）条件下贮藏 7 天的含 500ppm4-甲基儿茶酚（4-MC）和不含 4-MC 的碎牛肉中酚类化合物与蛋白质巯基之间的相互作用。提取肌原纤维蛋白分离物，并通过 ESR 光谱测量蛋白质自由基强度评估其氧化稳定性，结果发现 4-MC 和无氧贮藏均可提高其稳定性。与在氩气中贮藏的样品相比，在氧气中贮藏的样品中发现巯基显著损失，而在添加 4-MC 并在氧气中贮藏的样品中则发现另外的损失。在添加 4-MC 的牛肉中，LC-MS 分析表明形成了巯基-醌加合物，这可以解释观察到的额外巯基损失。尽管如 SDS-PAGE 评估的那样，无氧贮藏抑制了蛋白质交联的形成，无论是存在还是不存在 4-MC，但在有氧贮藏的牛肉中，4-MC 对蛋白质二硫键交联的形成没有抑制作用。
