External treatments can be applied to meats to increase their tenderness. These include the use of enzymes, salts, acids, and mechanical methods such as grinding or pounding.

Enzymes. One of the reasons that contracted muscles begin to “relax” toward the end of rigor mortis is that proteolytic enzymes work internally to break down the proteins within the muscle fibrils. A more even distribution of enzymes may be achieved by injecting a tendering solution of papain, or some other proteolytic enzyme, into the bloodstream of animals ten minutes before slaughter. Read more »