2. The stomach of hairy crabs after satiety is the 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.
The boundary between yellow and black 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 composition is basically the same as crab yolk.
Extended data
Whether a crab is safe or not depends first on the waters where it grows. If it grows in good waters, the heavy metal content of crabs is very low. But if you grow in polluted waters, crabs will naturally be polluted. American media reported that crab roe in new york waters contains environmental pollutants, such as dioxins, polychlorinated biphenyls and heavy metals, which are carcinogenic.
Therefore, the rumored crab should only refer to a polluted water area in new york. At present, most crabs in China are farmed artificially. Compared with the wild environment, cultured crabs are controllable. If the water quality and medication are qualified, crabs can be safely eaten.
Secondly, from a biological point of view, even if the water is polluted, the parts where the chemical substances of crabs are concentrated are actually inedible parts such as crab cheeks, crab lungs and crab liver. Even if crab roe is polluted, the number of crab roe is very small after all, and it is not eaten every day, so there is no need to panic.
References:
Wang reveals the reason why crab roe turns black.
References:
People's Daily Online-Is crab roe really inedible?