Marinades
Marinades
Marinades serve two different functions: as a tenderizer and flavor enhancer.
Marination is the process of soaking foods in a seasoned, often acidic, liquid before cooking. The 'marinade', must be either acidic with ingredients such as vinegar, lemon juice, or wine or enzymatic (made with ingredients such as pineapple or papaya or fungal enzymes.) Along with these liquids, a marinade often contains oils, herbs, and spices to further flavor the food items. The process may last seconds or days. Different marinades are used in different cuisines.
For example, in Indian cuisine the marinade is usually prepared with mixture of spices.
Marinades and Enzymes
Tough cuts of meat benefit from the tenderizing effects of marination by allowing enzymes long contact time with the tough proteins.
Meat contains connective tissues that can make certain cuts of meat very tough. The most common type of protein in connective tissue is collagen (white connective tissue). Collagen is a long stiff protein made up of 3 amino acid chains twisted around each other like a rope. The more collagen a piece of meat contains the tougher the meat is to chew. Collagen is tough and only becomes palatable if given enough time, temperature and moisture. Some collagen can be physically removed by cutting it out before cooking, however there is also collagen running through the muscle that can only be converted to gelatin by long and hot cooking methods with lots of moisture. As a general rule of thumb, meats high in collagen are cooked long and wet. Meats low in collagen are cooked hot and fast. Load bearing muscles of cows and pigs (legs, chest and rump) contain more collagen.
The second type of connective tissue elastin (yellow connective tissue) is not affected by cooking methods. If a cut of meat is high in elastin, it may need a little assistance to bring it to a palatable range of tenderness using enzymes.
Certain plant and fungi enzymes and acids can break down muscle and connective proteins in meats. Pineapple and papaya have long been used to tenderize meats. Modern science has created fungal proteases which are concentrated enzymes which digest or act on very specific protein bonds. Connective tissue that comes in direct contact with the protein-digesting enzymes gets broken down. These tenderizing enzymes also reduce the capability of the meat to hold its juices, resulting in greater fluid loss and thus drier meat. Excess levels of the enzymes can have the negative effect of making the meat 'mushy'.
Enzymes are heat activated at levels between 140 and 175 degrees F. and deactivated at the boiling point. Allowing the meat to sit at room or refrigerated temperatures serves no purpose other than flavoring.
Marination requires direct contact with the connective tissue, since it is necessary for the chemical reaction to occur. This means that soaking a piece of meat in a marinade will only penetrate just so far into the surface of the meat. If you marinate a large cut of meat in a tenderizing marinade, you end up with a mushy exterior and an unaffected center. Puncturing the meat for the marinade to penetrate gives an uneven result, with the further undesirable side effect of allowing the meat to lose even more juices while cooking. Applying a vacuum on the meat and marinade and releasing the vacuum can help the marinade and its enzymes to penetrate the meat deeper and faster. However, flat cuts of meat benefit most from tenderizing marinades.