ZT:

The most popular meat tenderizer, called bromelain, is composed of a number of protease enzymes and harvested commercially from the stems of pineapple plants, where

it is concentrated. The substance can be found throughout the entire plant, but is harvested from the stems because they are usually not consumed and are therefore available to be processed. Besides being a meat tenderizer, bromelain is an excellent anti-inflammatory agent, blocking metabolites that cause swelling. It has been used effectively to treat sports injuries and swelling caused by arthritis.