The natural tenderization of meat is a slow process brought about by endogenous enzymes (neutral protease and collagenase).
Industrial enzymes preparations are used to accelerate this process in order to reduce moisture loss and shrinkage of the tissues. This preparations involve plant proteases (papain and bromelain).
To achieve an even distribution of the enzymes in the tissue, preparations are sprinkled on the surface of meat and injected under pressure in the interior.