When you think of a tropical fruit, what comes to mind? Perhaps a mango? A banana? A papaya? Like many people, you might have said pineapple, one of the most recognizable fruits with their crowning leaves and spiky skin. Now imagine yourself eating a sweet and juicy pineapple on a hot summer’s day.
Picture the flavours and texture of the fruit on your tongue. Then think of the aftertaste that lingers in your mouth once it has been swallowed. Do you feel a burning sensation in your mouth, a feeling of soreness or a tingle? If you asked these series of questions to anyone who’s ever had a pineapple, chances are they’d agree and say yes. In fact, it happens to virtually everyone, though some maybe more severe than others.

The reason behind this phenomenon honestly sounds like something straight out of a horror film. In short, when you eat a pineapple, the fruit itself is actually… eating you back! Like all fruits, pineapples contain enzymes. However, what differentiates this tropical fruit from others is the enzyme bromelain. Bromelain is a protein-digesting enzyme that is found in most parts of the fruit. When extracted, it can be used as a topical medication, for cosmetic purposes, and as a meat tenderizer. It can aid in the reduction of
inflammation and swelling in the mouth, as well as the removal of dead skin from burns and cuts.

Enzymes are a type of protein that acts as a “fast-forward” button for your cells. They help regulate and speed up the rate at which chemical reactions happen within your body. Without enzymes, the metabolism of a human body would be too slow for anything to function. They also play an important role in digesting the food that you eat. For humans, our stomachs are strong enough to handle bromelain; however, our mouths are not. The inside of our oral cavities is coated with a protective layer of mucous. ( a lining of membrane ). The oral mucus’ job is to act as a barrier between the food/things we put in our mouths. It protects deeper tissues, such as muscle and fat from external dangers. It also contains keratin, a type of protein. And since bromelain is a protein-hungry enzyme, it can start to deteriorate the protective layer of mucus. The enzyme is practically “eating away” at the oral cavity membrane, which therefore causes discomfort.

Not only that, but pineapples can occasionally contain lots of acid (depending on the ripeness), which can also trigger the tongue and create an unpleasant sensation, alongside the decreased
strength of mucus. The good news is, once the pineapple has been swallowed, your stomach acids will burn away the enzymes, halting their reign of terror inside your body.

Nevertheless, there are ways to reduce the amount of bromelain in a pineapple, or direct it somewhere else. For example, eating the fruit with dairy can help divert attention away from the proteins in your mouth and onto those in lactose. Dairy can also help balance out the pH caused by the acidity, toning down the sting. Another method would be to cook the pineapple, which would remove the majority of the enzymes. By heating up the pineapple to a certain degree, the heat will destroy any microbes and enzymes on the fruit, thus “sterilizing” it.

Scientific and medical scheme about enzymes. Enzyme substrates and active sites, chemical and biological processes. Isolated flat enzyme diagram vector illustration.

Nutrition is a vital part of keeping the human body healthy. When we better understand the science behind the food we put in our mouths, it creates a healthier relationship between the mind and food. So, the next time you enjoy a pineapple and feel that slight tingle in your mouth, remember this. Just know that an enzyme by the name of Bromelain is secretly attempting to eat you from the inside out.