What is Cooking Loss in Meat?

Cooking Loss Definition

Cooking loss is the degree of shrinkage of meat during cooking. The total loss that occurs during the cooking of meat includes the losses known as drippings and the volatile losses. The greater part of the volatile loss is from evaporation of water. It may include volatile substances from the decomposition of fat and volatile aromatic substances. The drippings include fat, water, salts, and both nitrogenous and non-nitrogenous extractives.

Cooking Loss in Meat

Cooking loss is a major issue that is associated with degree of doneness, especially in steaks. The reasoning it is more associated with steaks is due to the fact that ground meat, chopped and formed products, and non-intact products are to be cooked to a minimum of 160 degree F. Therefore, cooking loss is generally of greater interest in whole muscle cuts. Dry cookery methods increase the amount of cooking loss due to the gradient in humidity. As with almost all things in nature, humidity tries to stay at equilibrium. Therefore, when the meat product is heated to temperatures capable of evaporating fluids, the liquids leave the muscle creating moisture loss. However, this is not the only reason for cooking loss. The main reason is that of steric effects in the muscle. When the muscle is cooked, it causes the proteins in the muscle to change in shape and conformation. This change in conformation causes them to shift and lose the ability to bind and hold onto water. This loss of ability allows for the cooking loss to occur.

Cooking loss is affected by many factors. These factors include final cooking temperature, pH of the muscle, and method of cooking. Higher final cooking temperatures increase the amount of water that is driven from the muscle as well as the amount of fat or lipid that is liquefied and allowed to excrete. 

Degree of doneness or final endpoint temperature has a direct effect on cooking loss. As the final endpoint temperature increases, the amount of cooking loss increases as well. 

The pH of the muscle also has a large role in the amount of cooking loss of a muscle. The pH is directly related to that amount of negative charges on the muscle proteins that bind the water molecules. When pH is close or at the isoelectric point (pI), the point in which in the net charge of the protein is equal, less water is allowed to bind. This occurs due to the lack of repulsion of the muscle fibers that allows space for the water to be trapped in the muscle matrix and also due to the lack of available charges to bind and hold on to water. 

Likewise, muscles that have an extreme high pH (those above 6.0) have the ability to retain a larger amount of water. In beef, it has been found that as pH increases, cooking loss decreases in roasts from the semitendenosus and longissimus muscles. Therefore, muscle pH that is above the pI has the ability to bind water. It must be noted however, that the pI of meat is 4.5, and meat has a large buffering capacity and moving the pH that low is tough, even in the worst of conditions. Minor changes in pH can affect cooking loss and ultimately juiciness of the meat.

Cooking method also has a large role in the amount of cooking loss. Depending on the method, cooking losses can be large or small.