Bromelain is really the culprit of "sticky mouth" when eating pineapple, but it will not be inactivated by soaking in salt water, which will protect the mouth. As for pineapple itself, it is a plant of the genus Bromeliaceae. It originated in the Amazon region of South America and was introduced to China via Southeast Asia at the end of the Ming Dynasty-which is no different from many tropical fruits in the New World. And like most succulents, pineapple will accumulate a lot of unpalatable substances to defend against herbivores, especially several protein hydrolases, which are collectively called bromelain. They can cut off the peptide bonds in the primary structure of proteins and hydrolyze them into polypeptides. When animals chew pineapple, the oral mucosa will be destroyed at a fairly fast speed, which will induce strong tingling and even bleeding. ? Therefore, bromelain is often used to prepare tender meat powder in food industry. When used to treat raw meat before cooking, it can destroy collagen and fibrin between raw meat cells, and also destroy cells, releasing protease contained in cells, making meat soft, smooth and easy to taste. But we don't want our tongues to be weak. How can we disarm pineapples? ? This is not a difficult thing-biology and chemistry classes in high school have taught us that enzymes are protein with catalytic ability. They are highly efficient and specific, but they are very fragile. They can only work normally at a suitable temperature and pH value, and there are many substances that can denature and inactivate them, such as alcohols and phenols. ? Bromelain can maintain its activity for a long time at room temperature and will not be destroyed by repeated freezing and thawing. The most active temperature is 40-60℃, but it will gradually deactivate at this temperature, and the higher the temperature, the faster the deactivation. ? This means that bromelain can keep its activity well during transportation, and then it will show its talents in your mouth, but it will keep its position as long as it is scalded with boiling water. Many Southeast Asian dishes will cook pineapple for this reason-and remind us not to add pineapple in the middle of the stew, which will not make the meat rot faster.