Anthocyanin glycosides have a special property: they turn red under acidic conditions and blue under alkaline conditions. For example, if you add a proper amount of vinegar to the water soaked in black wolfberry, the color will turn dark pink, and if you add a certain amount of alkali or baking powder, the color will turn blue-purple.
Besides Lycium barbarum, purple and black foods such as mulberry, purple sweet potato, strawberry, cherry, grape, purple cabbage, black bean, black peanut, black sesame, black rice and purple rice are also rich in anthocyanins.
Therefore, it is normal that the water soaked in these foods turns purple or light black. Eggplant anthocyanins only exist in the peel, and the epidermis is protected by a layer of transparent epidermal cells, which will not fade when washed normally.
The fading speed of purple-black food is related to anthocyanin content and soaking water temperature. The higher the water temperature, the faster the pigment dissolves. For example, when black peanuts are soaked in cold water for about 1 minute, prominent pigments will be dissolved. Put a glass of water into hot water at 60℃, and it only takes a few seconds to dye it purple-black.
Extended data
Precautions for drinking black wolfberry:
1, when soaking black wolfberry, be sure to control the amount, don't soak it too thick, and don't drink a lot of black wolfberry tea often. If you eat too much black wolfberry, it is likely to cause redness, swelling and pain in your eyes, and your eyesight will get worse and worse.
2. Lycium barbarum is also a certain taboo crowd, not everyone is suitable. Some patients with yin deficiency or people with weak spleen and stomach, as well as people with cold, fever and inflammation are not suitable for eating black wolfberry, especially those with high blood pressure and too impatient temper, which will cause serious harm to the body.
People's Network-Black Lycium barbarum is soaked into "purple liquid medicine", can it be eaten?
What are the nutritional functions of Lycium barbarum? What should I pay attention to when eating black wolfberry?