Chemical Methods of Meat Tenderization: Salts
Salt, both sodium chloride—the salt most of us are talking about when we say "salt" in the kitchen—plus many other salts in the scientific sense of the word, can act as powerful meat tenderizers. When dissolved in water, sodium chloride can dissolve some muscle proteins like actin and myosin; this is true whether the salt is dissolved in a wet brine or in the meat's own juices after the salt has been applied in a dry brine. This not only tenderizes the meat by breaking apart some of the muscle's structure, but it also lessens the degree to which a piece of meat contracts during cooking. Less contraction means less juices being squeezed out, leading to an overall more plump and tender piece of meat.
It's safe to say that of all the tenderization methods out there, applying salt in one form or another is almost always a good choice: It seasons the meat (almost never a bad thing) and improves both texture and juiciness. It's almost entirely pro with very little con.
Other salts that can be used as tenderizers include baking soda and salts of phosphoric acid or phosphates that can also dissolve muscle proteins and improve the tenderness and juiciness of the meat. As we found in a series of marinade tests, while baking soda is a tenderizer, it can also produce some unfortunate effects on a piece of meat and should be used with caution. Salts of phosphates are commonly used to tenderize meats like pork, for example—check the ingredient list on the label of pre-brined pork loin from a grocery store, and you’ll notice phosphates included.
At home, you can take advantage of the tenderizing effects of phosphates by using dairy. Dairy in the form of milk or fermented milk products like yogurt, buttermilk, or kefir contains a large number of phosphates that will improve the texture of meat. In addition to the salt and phosphates, fermented dairy contains lactic acid, a wonderful meat tenderizer that my own tests showed is not as prone as other common kitchen acids to turning the meat mushy.
Another common pantry staple that can help tenderize meat is mayonnaise, an emulsification traditionally made from egg yolks, vinegar or lemon juice, and oil. Egg yolks are rich in phospholipids, phosphates, and proteins, all of which help solubilize proteins in meat while amping up and stabilizing the emulsification of protein, fat, and water that forms on the surface of the meat. The meat locks in more water, resulting in a juicier, tender cut.
Biological Methods of Meat Tenderization: Aging, Enzymes, and Bacteria
Enzymes and Aging
One could correctly argue that enzymes are technically chemicals, and therefore belong in the section above on chemical methods of meat tenderization. But I prefer to include them under the biological tenderization umbrella, since they derive from biological sources and processes.
Humans have tenderized meat with enzymes, even if they didn't know they existed, since ancient times. In Korea, pear juice was applied to meat before cooking and in tropical and subtropical countries, papaya leaves and fruit were added to meat to make it more tender. These fruits contain enzymes called proteases that can recognize proteins and snip them up like scissors.
Besides pears and papayas (the enzyme is called papain), other plant sources of proteases include pineapples (bromelain, the key active ingredient in Adolph’s brand tenderizer), figs (ficin), kiwis (actinidain), melons, ginger (zingibain), and mangoes. These enzymes only work on the surface of the meat they come into contact with, since proteases are large protein molecules and cannot penetrate deeply into the meat.
In addition, the enzymes from these fruits will only work if raw, and some fruits, like papayas, must come from unripe fruits. Canned and cooked fruit won’t work as meat tenderizers because the protease enzymes get inactivated and denatured during heating. Protease enzymes can also be obtained from animal sources, and some of these, like trypsin, pancreatin, and pepsin, are used to tenderize meat.
Keep in mind, though, that enzymes require optimum conditions (temperature, pH, and time) to work efficiently.
When an animal dies, the tissue cells send signals that activate a cascade of biochemical signals to induce destruction. This process is known as apoptosis or "cell death." Enzymes within the muscle cells and the extracellular matrix kick into full gear and start degrading muscle proteins, making the meat more tender.
Under optimal storage conditions, meat can be aged such that we can take advantage of the benefits of cell death without the meat actually going bad. Beef can be aged by dry or wet methods. In dry aging, the beef is stored in a cold refrigerator unwrapped while in wet aging, the meat is vacuum packed before storage.
When meat is aged properly (some like to say it's being "ripened" or "conditioned"), its texture, and sometimes flavor, are noticeably improved. During this period, the muscles undergo various biochemical reactions like proteolysis, lipolysis, and oxidation that produce changes in the muscle's protein and fat content, improving the meat’s flavor, color, and texture.
