The Relationship of Intramuscular and Subcutaneous Fat to the Physical and Chemical Composition and the Organoleptic Properties of Beef

One hundred and thirty-five steer and heifer carcasses were used to study the relationship of intramuscular and subcutaneous fat to the physical and chemical composition and to the organoleptic properties of beef. Steer carcasses ranging in USDA grade from high standard to high choice and heifer carcasses ranging from low to good to high choice were included.

A significant (P < 0.05) positive relationship existed between USDA carcass grade and taste-panel tenderness scores of 6-7-8th rib roasts. Grade, marbling and percent ether extract of longissimus dorsi muscle were each significantly (P < 0.05) related to juiciness scores of 6-7-8th rib roasts and club steaks. These relationships were not generally high and were somewhat inconsistent. Overall grade marbling or percent ether extract of l. dorsi muscle had almost the same influence on the east quality of beef. Eating quality was not significantly (P < 0.05) affected by fat thickness. For the 9-10-11th rib roasts from both sexes, percent separable fat was influenced more by fat thickness than by grade.

Percent protein content of cooked rib roasts had a significant positive influence on shear values obtained on roasts from heifers and a significant negative effect on juiciness scores of roasts from both sexes. Flavor was significantly related to percent protein content of cooked roasts from heifers. Juiciness and tenderness scores were significantly (P < 0.05) increased as percent ether extract of cooked roasts from heifers increased. Percent protein content of cooked steaks from both sexes had a significant positive effect on shear value of club steaks and a significant negative effect on juiciness. For steaks from steers tenderness and flavor scores were significantly affected in a positive and curvilinear manner by percent protein content of cooked steaks.

It was concluded that USDA quality grade and marbling cannot be used effectively to predict the degree of eating satisfaction experienced by the consumer.