U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


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Published in Beef Research Program Progress Report (1993) No. 4 (Part 1): 139-140


The recently completed National Tenderness Survey and Beef Quality Audit have clearly demonstrated that variation in beef tenderness at the consumer level is one of the major problems that face the meat industry. Because of this, and since consumers consider tenderness to be the principal component of meat quality, scientists in the Meats Research Unit of U.S. Meat Animal Research Center have placed a special emphasis on understanding factors that determine beef tenderness.

To enhance tenderness, meat is normally aged (as wholesale cuts or carcasses). During this aging period a number of changes occur in the meat which result in loss of its strength. This is translated into less resistance during the chewing of meat after cooking; therefore, tenderness is improved. Over the past decade, we have determined the cause of the tenderization process during cooler aging. Meat is composed of long fibers that are held together by a rope-like structured protein called desmin. During cooler aging, this protein is broken down by naturally occurring enzymes called calpains. The amount of calpain activity will determine the extent of improvement in tenderness with aging. Calpain is a unique enzyme system which can degrade proteins only when sufficient calcium is present. With this knowledge, U.S. Meat Animal Research Center scientists have developed a procedure that produces tender meat at its maximum level only one day after slaughter. The procedure involves infusion of carcasses, or injection of meat cuts, immediately after slaughter with a calcium chloride solution (3.3%). The addition of calcium chloride causes maximum activation of the calpain system; therefore, maximum tenderization occurs in a short time.

Historically, crossbreeding has been widely used as a means of improving efficiency of beef production. The economical value of Bos indicus breeds of cattle in crossbreeding programs in semitropical and tropical climates has been well established. One of the major problems associated with inclusion of Bos indicus cattle in cross-breeding programs is that meat from these cattle has objectionable tenderness ratings. Previous research by U.S. Meat Animal Research Center scientists indicates that the reason for meat tenderness problems associated with Bos indicus carcasses is lack of tenderization during cooler aging. Because we had demonstrated the effectiveness of calcium chloride in improving meat tenderness, the objective of this experiment was to determine whether calcium chloride injection could improve tenderness of meat from Bos indicus carcasses.