The discoloration process from raw shrimp to cooked shrimp is completed by a pigment called astaxanthin, which is a kind of carotene family and is naturally orange-red. Astaxanthin has always existed in shrimp, but when shrimp was born, astaxanthin was associated with protein molecules, and it looked blue/gray. Heat "denatures" protein and destroys the combination of astaxanthin and protein, which is the reason why shrimp turns red when cooked.

And the color of shrimps and crabs is also related to their environment. The species of pigment cells in the dermis of shrimps and crabs in fresh water and land are less than those in crustaceans in the sea, so the color is relatively monotonous. The shrimps and crabs in the ocean are brighter in color and more beautiful in stripes.

Matters needing attention in cooking shrimp

1. It should be noted that shrimp cannot be cooked in cold water. Boiling shrimp in cold water takes too long, the meat is too old, and eating meat is very firewood. Be sure to boil the water before putting the shrimp, so that the shrimp is tender but not fishy.

2. If the shrimp is cooked in fresh water, be sure to add a little salt to the water, so that the cooked shrimp tastes good and the meat is tender.

3. The new prawns with knives must be cooked over high fire. Boil the shrimp for 2 minutes at most, and cook the shrimp for 1 minute at most. Shrimp meat will get old if cooked too long.