Why is purple potato blue-green when cooked? Can you still eat in this situation?

You can eat it without rotting. The discoloration of purple sweet potato is generally caused by contact with alkaline chemicals, which is related to the high content of proanthocyanidins in purple sweet potato. This is a natural plant pigment, which only needs to turn red when it meets acid and blue when it meets alkali. This normal situation causes purple sweet potato to become discolored and edible, without affecting health. However, if it is found that purple potatoes not only change color, but also rot, they can't be eaten.

According to the above basic principles, purple sweet potato will turn emerald green when it meets strong alkaline natural environment, and dark blue when it is weak alkaline, which is the same as the principle of Lycium barbarum soaking. Usually, because proanthocyanidins are an unstable water-soluble pigment, it will change color because of the level of strong acid and alkali, which will not be affected by food nutrients and can be safely eaten.

The proanthocyanidins in purple sweet potato will have different color changes in different natural environments. If it turns bright red in acidic natural environment, it will turn dark blue in alkaline natural environment, and it needs to turn green and purple in the process of connection. If it is any deeper, it will turn gray-black. This color change is normal.

There are more and more cooking methods of purple potato, such as porridge and snacks. In order to maintain the original blue-purple appearance of purple sweet potato, it is best to cook purple sweet potato to avoid fading caused by contact with alkaline water.

Of course, if you like purple potato porridge but don't want to change color, here is a little trick to help you. You can try adding a proper amount of white rice vinegar or squeezing a small amount of lemonade in porridge water, which contains acidic components, which can neutralize alkaline water quality and prevent purple potato from discoloring during cooking.

There is no dyed purple potato at all. Some people say that the purple potato I bought is sometimes dark purple and sometimes lavender. Can this purple potato be dyed? In fact, this kind is probably very small, because on the one hand, purple potatoes are easy to rot and deteriorate when dyed, but the market price of purple potatoes is not very high. If it is dyed and stored for a short time, it will deteriorate and cause greater damage if it cannot be sold. On the other hand, the color of purple sweet potato may be the same in the growth process, and it is normal that the color distribution is slightly uneven.