为什么牛腩抄水后会变黄色？

牛腩是一道美味的传统菜肴，在炖煮过程中，常常需要先将牛腩焯水。然而，有时候人们会发现，牛腩在焯水后会变成黄色，这可能会引起一些疑问。那么，为什么牛腩抄水后会变黄色呢？

首先，牛腩在焯水的过程中会释放出一部分血水和杂质。这些血水和杂质含有一定的蛋白质和其他化学物质，当与开水接触时，会发生一系列的化学反应。其中一个重要的反应是蛋白质与水中的氯离子结合形成氯胺。

此外，牛腩内部的骨髓也会渗出一些黄色的物质。这些物质含有一种叫做骨胶原的蛋白质，它在高温环境下会发生变性反应，导致颜色变化。

最后，牛腩本身含有一定的嘌呤物质，如尿酸。当牛腩与开水接触时，这些嘌呤物质也会与水中的化学物质发生反应，导致颜色变化。

总结起来，牛腩抄水后变黄色的原因主要是由于血水和杂质的存在，以及骨髓中的骨胶原蛋白质和牛腩中的嘌呤物质与开水发生化学反应所致。这些反应导致了颜色的改变。

Why does beef brisket turn yellow after blanching?

Beef brisket is a delicious traditional dish that often requires blanching before stewing. However, sometimes people find that beef brisket turns yellow after blanching, which may raise some questions. So why does beef brisket turn yellow after blanching?

Firstly, during the blanching process, beef brisket releases some blood water and impurities. These blood water and impurities contain certain proteins and other chemicals which undergo a series of chemical reactions when in contact with boiling water. One important reaction is the combination of protein with chloride ions in the water, forming chloramine.

Additionally, the bone marrow inside the beef brisket may secrete some yellow substances. These substances contain a protein called collagen, which undergoes denaturation at high temperatures, resulting in a color change.

Lastly, beef brisket itself contains a certain amount of purine substances, such as uric acid. When beef brisket comes into contact with boiling water, these purine substances also interact with the chemicals in the water, leading to a color change.

In summary, the main reason for the yellow color change in beef brisket after blanching is due to the presence of blood water and impurities, as well as the reaction between collagen protein in the bone marrow and purine substances in beef brisket with boiling water. These reactions cause the color change.