Purple sweet potato usually turns green due to contact with alkaline substances, which is related to the high anthocyanin content in purple sweet potato. This is a natural plant pigment, which turns red in acid and blue in alkali. This normal phenomenon causes purple sweet potato to turn green, which does not affect health. However, if it is found that purple potatoes not only turn green, but also rot and deteriorate, they can't be eaten.

Purple sweet potato can be eaten when it turns green with alkali.

According to the above principle, purple sweet potato will turn green when it meets strong alkaline environment, and turn blue when it is slightly alkaline, which is the same as the principle of soaking black wolfberry, because anthocyanin is an unstable water-soluble pigment, which will change color because of the degree of acid and alkali. This green phenomenon does not affect the nutritional composition of food, so you can eat it safely.

Note: Anthocyanins in purple sweet potato will have different color changes in different environments. If it turns red in acidic environment, it will turn blue in alkaline environment, turn green and purple in the transition process, and turn black when it is deep. These color changes are normal.

How to avoid purple potato turning green 1? There are many ways to steam purple potatoes, such as cooking porridge or making cakes. If you want to keep the original purple appearance of purple potato, it is best to steam it, so that purple potato can try to avoid contact with alkaline water and cause its discoloration.

2. Add some vinegar or a few drops of lemon juice. Of course, if you like to drink purple potato porridge but don't want to turn green, here is a little trick to help you. You can try adding a proper amount of white vinegar or squeezing a few drops of lemon juice into porridge water, which contains acidic components, which can neutralize alkaline water quality and prevent purple potatoes from turning green during cooking.

Is purple potato dyed? There is almost no dyed purple potato.

Some people say that the purple potato I bought is sometimes dark purple and sometimes light purple. Can this purple potato be dyed? In fact, this possibility is very small, because on the one hand, purple potatoes are very perishable if dyed, but the price of purple potatoes is not high. If it is dyed and preserved soon, it will be bad and the loss will be greater. On the other hand, purple sweet potatoes can't all be the same color in the growth process, and it is normal that the color distribution is slightly uneven.