Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Nutrition and Food Science

Committee Chair(s)

V. T. Mendenhall


V. T. Mendenhall


Georgia C. Lauritzen


Deloy Hendricks


Gary Straquadine


The objective of this study was to determine the effect of aging on the tenderness and palatability of beef from the semitendinosus muscle of the round. Tenderness may be affected by the length of the aging period and the aging temperature. Steaks from the semitendinosus muscle were stored for 0, 3, 6, 9, 12, and 24 hr at two temperatures, 43.3°C and 2.2°C. Ultra high temperature (UHT) pasteurization was accomplished by subjecting the meat to 1100°C for 20 seconds. UHT pasteurization denatures surface proteins, destroys vegetative pathogens, and eliminates some spoilage organisms from the surface of the meat. UHT -treated steaks were cooked in a microwave oven to an internal temperature of 71.1°C. Two cores were taken from the center of each cooked steak. Shear values (lb) were determined on the cores using a Warner Bratzler shear. The results of the study showed that the UHT-treated steaks that were stored at 43.3°C were significantly more tender than those that were refrigerated at 2.2°C regardless of the length of the aging period up to 24 hr. Additional tenderness at 2.2°C when the aging period exceeds 24 hr may be possible.

Total plate count (TPC) of raw and UHT-treated steaks was determined using the standard plate count method. The average TPC for the raw steaks was significantly higher than the UHT-treated steaks. The TPC was not significantly different between the UHT- treated steaks that were aged and those that were not aged. A trained panel was used for sensory evaluation to evaluate the moistness, tenderness, and flavor of the steaks using a 9-point hedonic scale.

Sensory scores of the UHT-treated steaks revealed that steaks stored at 43.3°C had significantly more moisture and were more tender than those stored at 2.2°C. The panel noted more spoiled flavor among the steaks stored at 43.3°C than 2.2°C. Steaks stored at 2.2°C received significantly higher flavor scores than those stored at 43.3°C.



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