A major factor in the color of many meat products is myoglobin. Myoglobin helps to transport oxygen throughout the muscle cell to produce energy. The quantity and the type of myoglobin in the meat determines the relative shade of the meat. The initial myoglobin quantity and type varies by animal age as well as physical activity of the muscle. The three major forms of myoglobin in ground beef are oxymyoglobin (myoglobin bound to oxygen, MbFe(II)O2), deoxymyoglobin (myoglobin bound to water) and metmyoglobin (oxidized myoglobin, MbFe(III)).
Fresh ground beef is normally associated with a red color. The red color is due to the myoglobin being predominantly in the form of oxymyoglobin. When ground beef gets older or is cooked the color changes to brown due to the oxidization and/or denaturation of the ground beef, turning the myoglobin to metmyoglobin. Metmyoglobin is the most stable natural state. Over time the ability of the myoglobin to absorb oxygen or water, and revert to oxymyoglobin, is reduced. After time, the myoglobin therefore remains predominantly in the metmyoglobin state. Beef and other products may also turn a brownish color when cooked because of the oxidation and denaturation of the myoglobin by heat. The brown color due to the metmyoglobin is not associated with fresh or desirable ground beef by the consumer. When ground beef is vacuum packaged it has more of a purplish color due to the myoglobin being predominantly present as deoxymyoglobin.
Finely textured beef (FTB), also referred to as fat reduced beef, is a lean edible by-product derived primarily from fatty beef trimmings. The raw material for FTB includes trimmings derived from boning and fabrication operations of a beef carcass. The raw material can be high in fat but contains visible lean meat. FTB is formed when the lean meat is separated through a rendering process to achieve a relatively low-fat lean meat product. Rendering is the heating of meat products to separate out the meat from the fat. Production of FTB changes the original trimmings from a fatty, low quality, low value product to a relatively lean and valuable product.
FTB is used in the meat industry as an ingredient in ground beef, raw hamburger patties, and frozen meat such as frozen hamburger patties. While FTB can help to reduce raw material costs for processors, it may be functionally inferior because the processing method to produce FTB can have a detrimental impact on color. During the processing of FTB the meat is rendered to remove the fatty material. The heating of the FTB during manufacturing can turn the meat a brownish color. The brownish color of the FTB may limit the amount of material that can be added to ground beef products that are being sold directly to consumers. There is therefore a need in the art for a method of retaining and improving the red color of meat during processing of meat trimmings to make FTB.