Due to insufficient heating time. Use live female crabs, heat them to 10 minutes, and then take them out and have a look. Crab yellow is black in the middle and yellow around. Put it in the pot for a minute or two, and it will be golden yellow when you take it out. It should just be that the heating time is not enough.

The stomach of hairy crabs after satiety is a black colloidal solid in crab roe. The reporter consulted Mr. Gu from the Department of Zoology, Xuzhou Institute of Bioengineering. After reading the pictures sent by the reporter, Mr. Gu said that the black jelly next to the crab yellow is the belly of the crab, also called the crab urine bag. It is located in the center of the front edge of the back shell and is a triangular bone bag with dirty sand inside, close to the crab yellow. Generally, when crabs are on an empty stomach, their stomachs will look smaller, but when they are full, their stomachs will swell up, and it seems that there are more black gelatinous substances, but this belongs to the normal category, and they can be eaten normally without the black gelatinous substances.

After female crabs mate, the yellow-black dividing line is obvious. Crab yolk is the ovary and digestive gland in the body. When the crab roe becomes large and bright orange, it shows that the gonad of the female crab is mature. At this time, crab eggs are produced and excreted, and the egg cells left in the gonads in the body still belong to crab yellow. Crab yolk is not crab yolk, but its nutritional components are basically the same as crab yolk. If you encounter black crab roe, then the female crab will breed offspring.