Black rice, in fact, only the waxy layer on its surface is black. After peeling off the waxy layer, it looks like ordinary white rice. The nutritional value of black rice mainly lies in this layer of wax. This case is water-soluble melanin, and it is normal to change color when washing black rice.

Black rice identification method: white vinegar identification method. Because the skin of black rice contains blue-white pigment, it will turn red when it meets acid solution, while artificial pigment will not change color when it meets acid solution.

Extended data:

Taboos and side effects

1. Rice has a tough seed coat, which is not easy to boil, so black rice should be soaked overnight before cooking.

2, people with weak digestive ability after illness, don't rush to eat black rice, but eat some purple rice to regulate.

3. If black rice porridge is not cooked, not only most of the signature nutrients cannot be dissolved, but also it is easy to cause acute gastroenteritis if eaten too much, especially for children with weak digestive function, the elderly and patients. So people with indigestion should not eat uncooked black rice.

4. Chinese medicine believes that black rice is flat and sweet; Not suitable for people with excessive heat.

5. Because the nutrients contained in black rice are mostly concentrated in the black cortex, it is not suitable for finishing. It is best to eat brown rice or standard third-class rice.

6. The copper content of black rice is 1~3 times higher than that of rice; Not suitable for patients with hepatolenticular degeneration and patients with high copper content.

7. It is forbidden to eat black rice when taking tetracycline drugs. When taking tetracycline drugs, eating black rice will form insoluble chelates with drugs, which will affect the absorption of tetracycline drugs and reduce the curative effect.

References:

People's Daily Online-Experts said that it is normal for natural grains to fade after soaking in black rice water.

Baidu encyclopedia-black rice