Meat and Meat Products Research Institute (IPROCAR), Veterinary Faculty, Universidad de Extremadura, Caceres, Spain.
Meat and Meat Products Research Institute (IPROCAR), Veterinary Faculty, Universidad de Extremadura, Caceres, Spain.
Food Chem. 2022 Dec 15;397:133805. doi: 10.1016/j.foodchem.2022.133805. Epub 2022 Jul 27.
The severe pro-oxidative environment in the stomach promotes oxidation of dietary components. The pro-oxidant molecular mechanisms of reducing sugars on this environment are unknown. To investigate the mechanisms involved in protein oxidation and nitration during a simulated gastric digestion (porcine pepsin, 37 °C, 2 h) of meat proteins, these were exposed to several dietary reactive components namely myoglobin, glucose, glyoxal, myoglobin + glucose and myoglobin + glyoxal. Two versions of each experimental unit were prepared depending on the addition or absence of nitrite. Compared to control (only meat proteins), myoglobin + glucose showed the highest pro-oxidative and pro-nitrosative effect (p < 0.001), likely caused by an increase in ROS derived from the degradation of glucose during assay. Nitrite promoted the occurrence of protein nitration but decreased protein oxidation in myoglobin-added groups (p < 0.001) by, plausibly, stabilizing heme iron. These results indicate the relevant role of glyco-oxidation during digestion of red meat with other dietary components such as reducing sugars.
胃内严重的促氧化环境促进了膳食成分的氧化。还原糖对这种环境的促氧化剂分子机制尚不清楚。为了研究模拟胃消化（猪胃蛋白酶，37°C，2 小时）过程中肉蛋白发生蛋白质氧化和硝化的机制，将肉蛋白暴露于几种膳食反应性成分，即肌红蛋白、葡萄糖、乙二醛、肌红蛋白+葡萄糖和肌红蛋白+乙二醛。根据是否添加亚硝酸盐，每个实验组都准备了两种版本。与对照（仅肉蛋白）相比，肌红蛋白+葡萄糖表现出最高的促氧化和促亚硝化作用（p<0.001），这可能是由于实验过程中葡萄糖降解产生的 ROS 增加所致。亚硝酸盐促进了肌红蛋白添加组中蛋白质硝化的发生，但降低了蛋白质氧化（p<0.001），这可能是通过稳定亚铁血红素实现的。这些结果表明，在消化含有还原糖等其他膳食成分的红肉时，糖基氧化具有重要作用。
