Least-squares analysis of several components of beef tenderness

Abstract

This study is part of a long-term program to investigate quality of beef. The purpose is to investigate the degree to which tenderness of beef is influenced by differences in sire, breed, age, carcass w eight, weaning w eight, year and season, sex, stilbesterol treatment, rate of gain, ribeye area, amount of fat over ribeye, and the relative importance of these factors. Another objective of this work was to establish some procedures to simplify application of the least-squares method of analysis of variance to this type of study. Production data from the Texas Agricultural Experiment Station Substation 23 records, slaughter records of the Animal Husbandry Department Meats Laboratory and results from cooking tests of the Food Research Laboratory records of the Home Economics Department on 159 animals slaughtered in 1959 and 1960 were used in this analysis. The animals were slaughtered at the Texas A. and M. Meats Laboratory, where detailed carcass data were recorded. Carcasses were aged seven days and frozen. Six steaks of uniform thickness were taken from two standard locations on each carcass. The cuts used were loin steaks from the lonqissimus dorsi muscle and bottom round steaks taken from the biceps femoris muscle. Each type of cut was broiled rare and well done, and braised well done by highly standardized cooking methods. Tenderness was evaluated by new methods developed by Cover (Cover et al., 1958; Cover and Hostetler, 1960) of the Home Economics Department of the Texas Agricultural Experiment Station. One -measure of tenderness was shear force, which was determined by means of the Warner-Bratzler shear apparatus. This measures the maximum force attained in shearing cores of cooked meat which are prepared for cutting by standard techniques. The meat was evaluated on the basis of one objective measurement, shear force, and six subjective measurements. The subjective measurements were: 1) tenderness of connective tissue; 2) mealiness; 3) ease of fragmentation of fibers; 4) adhesion of the fibers; 5) softness to tooth pressure; 6) softness to tongue and cheek. The subjective score for each steak for each of the components listed above was determined by averaging the scores of four judges..