When buying prawns, if you pay close attention, you will see that some prawns have black heads and tails. The enzyme reaction is the reason why prawns turn black. This often occurs when prawns are exposed to high temperatures, lack of oxygen or some other causes. Therefore, if you see the prawns’ head and tail turn black, it means that the prawn has been left for a long time and shows signs of spoilage, it is best to avoid it.
2. Avoid the hard prawns that are not curling
If you find the prawns hard and straight, it is a sign that the prawns has been injected with impurities. Normal prawns are soft and curved. Injected prawns often feel hard and bloated. When cooked, chemically injected prawns often lose a lot of water and the meat will shrink significantly compared to before processing.
