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Why is lotus root soup black

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Why is lotus root soup black? Many people said that the lotus root and ribs soup stewed in an iron pot turned into black ink accidentally. Lotus root soup and vegetables are delicious, but it is easy to turn black. Even if it tastes delicious and looks bad, it is difficult to increase people's appetite. How to cook lotus root soup without being black? How to cook lotus root soup without being black? Why is lotus root soup black

Spare ribs lotus root soup is a good choice for tonic in autumn and winter, but it is very learned to cook lotus root soup. Many times, the lotus root soup is black, which is really ugly. This is because lotus root is rich in iron and tannin chemicals. Iron will oxidize when heated, and its color will turn dark. The phenols in tannins produce quinone polymers to form brown pigment. The color of soup and lotus root will gradually deepen, which is also known as tannin. In addition, another reason for tannin discoloration is the formation of dark tannin salt with metal, which turns blue in case of iron.

Generally, the lotus root soup cooked in an iron pot is black. If you don't use an iron pot, it may be that the lotus root is not fresh, or it has been put for a long time, and it is black when cooked.

How to cook lotus root soup will not be black

1. It is best to cook with ceramic or stainless steel utensils, and avoid using iron pot, aluminum pot and iron knife to reduce oxidation and blackening.

2. If you cook the soup for a long time and heat it repeatedly, as well as if the temperature is too high (such as using a pressure cooker), the oxidation will be sufficient, and the lotus root will turn black slowly when you cook the lotus root soup. Therefore, don't cook the lotus root soup slowly for a long time.

3. Scald the lotus root with boiling water first. It is not difficult to keep the lotus root white. Blanching in boiling water at 100 ℃ for 70 seconds can make all polyphenol oxidase lose its function, which stops the transformation process from polyphenols to quinones. This method is suitable for lotus root stew.

4. In addition to high-temperature treatment, the appropriate addition of acidic substances can also bind the hands and feet of polyphenol oxidase. For example, adding vinegar can largely avoid the catalysis of polyphenol oxidase and keep the lotus root white. Methods: prepare a basin of cold water, put a certain amount of white vinegar in the cold water, and soak the lotus root in it for a while. The acidic substances can inhibit the catalysis of polyphenol oxidase, so that the lotus root will not blacken and change color, and maintain its white color.

5. The lotus root is easily oxidized and discolored by the air after cutting the skin. To avoid this situation, the best way is to isolate the lotus root from oxygen before frying. Therefore, in order to prevent discoloration, soak the cut lotus root in clean water or salt water to prevent the lotus root from turning black.

6. Peel the lotus root and cut it into pieces. Soak it in hot water and a little salt for 1-1.5 hours before putting it into the pot.

7. Lotus root must not go down too early. It will be black after stewing for a long time. When stewing spare ribs, you must clean up the blood bubbles floating on the surface.

8. If the lotus root is not used up at one time, it can be covered with fresh-keeping film. In particular, the cut part can be wrapped and stored in the refrigerator for about one week.

Can lotus root soup be drunk when it turns black

From the reason why the lotus root turns black, the blackened lotus root soup can be eaten naturally. However, if it's because it's blackened after too long, it's certainly not fresh. Don't eat it. Lotus root soup turns black. If it is not because of deterioration, it can be drunk. Of course, the taste will be much worse and the nutrition will be discounted.