Date of Graduation


Document Type


Degree Name

Master of Science in Animal Science (MS)

Degree Level



Animal Science


Charles Rosenkrans, Jr.

Committee Member

Jason Apple

Second Committee Member

Elizabeth Kegley


Consumer Sensory Panel, Cookery Method, Fat Content, Finely Textured Beef, Ground Beef, Precooked Burger Patties


Variation in internal cooked color of ground beef is an economic concern for the ground beef market. Persistent pink color in hamburger patties can lead consumers to the perception of an undercooked product. Therefore, the objective of this study was to characterize the effects of bull:cow blend proportions, with or without finely textured beef (FTB), and cookery method on internal color of precooked ground beef patties. Batches (9.1 kg) of 85% lean ground beef were manufactured with 0, 33, 67, or 100% 50:50 bull:cow blend (remainder of lean was 100, 67, 33, or 0% Select-grade knuckles, respectively) mixed with 2 kg of 50:50 lean:fat trim and either 0 or 15% FTB, resulting in 8 treatment formulations with 5 replicates. Batches were mixed in a commercial mixer-grinder for 5 min before being ground through a 0.95-cm plate, and formed into 150-g patties (40/batch). Fresh color (L*, a*, and b*) was measured after patties were formed (n=6/ treatment batch). Patties were cooked in an impingement oven to internal temperature of 71°C, submerged in an ice bath before measuring internal cooked color (n=6). The next day, frozen cooked patties were reheated to an internal endpoint temperature of 71°C on a char-grill (CHAR), clam-shell griddle (PAN), or forced-air convection oven (OVEN) before measuring internal reheated color. Data were analyzed as a slit-plot design, with the whole plot treatments in a 4 × 2 factorial arrangement with PROC GLIMMIX of SAS. Fresh patties became darker, less red, and more yellow (linear, P ≤ 0.012) with increasing proportions of bull:cow blend, whereas FTB addition increased (P < 0.05) L* values and decreased (P < 0.05) a* and b* values of fresh patties. Cooked patties became darker (linear, P < 0.001) with increasing bull:cow blend, and addition of FTB reduced (P < 0.05) internal a* and b*. Reheated L* values decreased with increasing bull:cow blend (linear, P < 0.001), and inclusion of FTB reduced (P < 0.05) a* values in reheated patties. Patties reheated in OVEN were lighter (P<0.05), more red (P < 0.05), and yellow (P < 0.05) than patties reheated in PAN or on CHAR.