Purple cabbage is rich in water-soluble pigment anthocyanin. When it fades in water, artificial pigment may not be added, but it is probably its original natural color. Anthocyanins are usually stored in vacuoles of plant cells. When cells are damaged, they will dissolve in water, and you will see what is commonly called "fading".

Edible pigments can be divided into water-soluble and fat-soluble according to their solubility. Water-soluble pigments are easy to dissolve in water and fade, while fat-soluble pigments do not fade in water. The higher the water temperature, the faster the pigment dissolves. For example, purple cabbage soaked in cold water takes about 1 minute to dissolve the pigment, while it takes only a few seconds to put it in hot water at 60℃.

Extended data

Selection of purple cabbage

1, point component

The same variety, it is better to choose the ball tightly and the hand is heavy. Heavy purple cabbage has sufficient water and compact structure. If the weight is similar when choosing, the smaller one is better.

2. Look at this color

The higher the gloss, the fresher the dish.

Step 3 look at the appearance

Purple cabbage with flat head and round head is better. These two kinds of Chinese cabbages are big, compact in structure, tender in meat, high in yield and good in taste, but the sharp ones are worse.

People's Daily Online-Does fading food necessarily mean being dyed?

People's Network-Purple Cabbage: The heaviest and freshest.