Papain is an enzyme which is found naturally in unripe papayas. This enzyme has a number of interesting uses, and it appears in a variety of settings. People have been taking advantage of its properties for centuries in Latin America, and additional uses have been discovered in the modern era with research on the enzyme and its properties.
The oldest historic use of papain is as a meat tenderizer. The enzyme helps to break down the tough bands between fibers in muscle tissue, making tough meats fall apart during the cooking process. Wrapping foods in leaves may be a stereotypical activity in fictionalizations of tropical life, but it has a sound basis in science, as green leaves can contain papain, which will soften the meat as it cooks while preserving moisture and preventing burning.
Historically, people harvested this enzyme by slashing the skin of unripe papayas and collecting the resulting sticky, latex-like sap which collected. People could also cook with upripe papayas, relying on the green papaya to break up in the cooking process and release the enzyme, or certain leaves could be added to a recipe to soften the meat.
Commercially, papain is added to many preparations which are designed to tenderize meats. It is also used in the preparation of cell cultures, as it can dissolve the bonds between cells to make them easier to separate. Medically, this substance is sometimes used in wound debridement and other procedures, and it is sometimes recommended as a dietary supplement to people who experience digestive problems. The supplement can help people break foods down so that they are easy to digest.
There are some precautions which must be observed when working with this enzyme. Some people develop an allergy to this enzyme, and they can experience severe health problems if they are exposed to it. Papain allergies can also be closely related to latex allergies, and people with sensitivity to one may develop a sensitivity to the other. Pineapples, kiwis, and cashews can also be related to a papaya allergy, as the enzymes in these foods are similar to papain.
People who are sensitive to papayas should avoid products like meat tenderizers made with papain, as they may experience allergic reactions. If allergies are experienced generically after eating tropical fruits such as the examples listed above, it can be a good idea to receive allergy testing to narrow down the cause to a specific culprit.