Mung beans have the effect of clearing away heat and toxic materials. Usually we often cook mung bean soup at home, but mung beans always turn red when cooked. None of the others changed color when cooked, and there were no red beans in them. What the hell is going on here? In fact, many people will encounter the discoloration of boiled mung bean soup. Let's discuss the reason today. How can cooking not change color?

Why does boiled mung bean soup turn red?

1. Cooking mung beans in an iron pot or stirring with an iron spoon will lead to discoloration. Most of the active ingredients of mung beans are in the skin of mung beans. The flavonoids in mung bean skin may form a dark complex after interacting with metal ions, which makes the color of mung bean soup red and black.

2. Boiling mung bean soup in cold water is easy to turn red. Mung bean skin contains a lot of polyphenols, which will change color as soon as they see oxygen. Cooking in cold water takes a long time and oxidizes quickly, and the soup is more likely to change color.

When cooking mung bean soup, some people find that the water is running out, so they choose to add cold water halfway. This is not right. If cold water is added, the mung bean soup in the pot will easily change color when it comes into contact with oxygen. Even if you want to add it, you should add boiling water.

How to make green mung bean soup?

1, it is better to cover the pot. Mung bean skin contains a lot of polyphenols, which can be easily oxidized into quinones as long as it is exposed to oxygen, and continue to polymerize into darker substances.

2. The color of mung bean soup cooked with different water quality is different. The color of distilled water is the greenest and remains unchanged for a long time. Followed by pure water and mineral water. The color of mung bean soup boiled in tap water changes the fastest, and it darkens obviously almost every minute after touching the air, and soon turns red. Therefore, it is best to cook mung bean soup with pure water.

3. The best way to cook mung bean soup is to boil water first, then add mung beans, continue to cook for 8~ 10 minutes, and then pour out mung bean soup.

Is mung bean soup red or green?

No matter whether the mung bean soup is red or green, the two kinds of soup cooked under normal circumstances are nutritious and safe to drink. Only by comparison, green mung bean soup will be more beneficial to health than red one.