Cooking purple potato porridge to prevent turning green can add a little white vinegar.

Vinegar is an acidic substance, and when you add some citric acid or acidic substances to the porridge, it will turn purple. Potatoes are rich in anthocyanins, and anthocyanins are a water-soluble natural pigments, with "acid to red, alkali to blue" characteristics. Rice porridge is alkaline environment, add purple potatoes, it will become blue, is a normal phenomenon, you can rest assured to eat.

In the purple potato juice in a few drops of edible alkaline water, purple potato juice will slowly become a blue-green color. And then add some white vinegar, acid and alkali neutralization of purple potato juice will slowly turn back to purple. If you add more vinegar, the juice will become acidic and turn red from purple.

This simple color-changing principle is applied to the kitchen, with the help of a small amount of white vinegar, edible alkali, it is very easy to identify black sesame, black beans, black rice and other anthocyanin-rich foods are stained.

Expanded

Purple potatoes are contraindicated:

Purple potatoes are contraindicated with persimmons, not only affecting the absorption of nutrients to the formation of stones, easy to cause gastric hemorrhage.

Purple potatoes and white wine, crabs, bananas with food, precisely because of purple potatoes containing low calories, very easy to lead to abdominal pain, diarrhea.?

People who are allergic to purple potatoes should not eat. Purple potatoes may also become allergens, if you are allergic to purple potatoes, consumption of purple potatoes may cause redness and swelling of the skin, frequent diarrhea, indigestion, headache, sore throat, asthma and other allergic symptoms, so this kind of people should also avoid eating purple potatoes.

Just eat raw. Purple potatoes should be cooked before eating, because the starch grain is difficult to digest without high-temperature damage.

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