The Effect of Age, Stretchtension During Thaw Rigor and Heat of Selected Quality Characteristics of Beef Sternomandibularis Muscle

Abstract

Some aspects of the phenomenon of thaw rigor have been studied in order to understand how it affects skeletal muscle as a food. Specifically, studies were conducted to evaluate the tenderness and other quality characteristics of muscle strips retained at rest length or stretched by 50 percent during thaw rigor, and to see whether any observed differences were related to the age or sex of the animals. No statistically significant differences due to the stretched state, age or sex were noted in the 24 hr. post thawing pH or water holding capacity as determined by the Carver Press method, although in the latter parameter, individual animals differed significantly (P<0.05) from one another. Differences in the stretched state affected the cooking loss, cooking contraction, shear values, sarcomere length and fiber diameter. Variations in the cooking loss, cooking contraction and sarcomere length were not significant when considered on between group basis while significant variations were observed in the shear values (P <0.05) and fiber diameters (P<0.01). Significant differences in the response of individual animals within t!e different groups were noted in the cooking loss, cooking contraction (P<0.01) and shear values (P<0.05). Within group) differences were not observed in the estimates of sarcomere length and fiber diameter. Significant differences were not noted in the total collagen, alkali-soluble collagen, and elastin contents of the cow, steer and heifer groups. However, the collagen content of the veal group was significantly greater (P<0.005) and was more readily soluble in dilute alkali than the three other groups. No significant differences in the collagen content or solubility was attributable to the stretched state. Heating of the muscle strips significantly affected col!agen solubility (P<0.005) in all the different groups