title: Carcass characteristics, the calpain proteinase system, and aged tenderness of Angus and Brahman crossbred steers.
abstract: We used 69 steers of varying percentage Brahman (B) breeding (0% B, n = 11; 25% B, n = 13; 37% B, n = 10; 50% B, n = 12; 75% B, n = 12; 100% B, n = 11) to study the relationship between carcass traits, the calpain proteinase system, and aged meat tenderness in intermediate B crosses. Calpains and calpastatin activities were determined on fresh longissimus muscle samples using anion-exchange chromatography. The USDA yield and quality grade data (24 h) were collected for each carcass. Longissimus steaks were removed and aged for 5 or 14 d for determination of shear force and 5 d for sensory panel evaluation. Even though some yield grade factors were affected by the percentage of B breeding, USDA yield grades did not differ (P > .15) between breed types. Marbling score and USDA quality grade decreased linearly (P < .01) with increasing percentage of B breeding. Shear force after 5 and 14 d of aging was higher (P < .05) in the 100% B steers than in all other breed types, which were not significantly different. Sensory panel tenderness and connective tissue scores decreased linearly (P < .05) with increasing B breeding. A quadratic effect was also noted for tenderness and connective tissue scores; 37% B steers received the highest scores. A similar response was found in mu-calpain activities; the 37% B steers had the highest activities. Conversely, calpastatin activity increased linearly (P < .01) with increasing percentage B breeding. These data show strong linear relationships between calpastatin activity (positive), marbling score (negative), and percentage B breeding, suggesting a possible combined effect of these traits on aged tenderness of intermediate Brahman crosses.
authors.affiliation: Animal and Dairy Science Department, University of Georgia, Athens 30602, USA.
authors.forename: T D
authors.initials: TD
authors.lastname: Pringle
authors.forename: S E
authors.initials: SE
authors.lastname: Williams
authors.forename: B S
authors.initials: BS
authors.lastname: Lamb
authors.forename: D D
authors.initials: DD
authors.lastname: Johnson
authors.forename: R L
authors.initials: RL
authors.lastname: West
mesh_terms: D000818:Animals; D001823:Body Composition / Q000235:genetics* / Q000502:physiology*; D001947:Breeding; D002135:Calcium-Binding Proteins / Q000032:analysis; D002154:Calpain / Q000032:analysis*; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D002852:Chromatography, Ion Exchange / Q000379:methods / Q000662:veterinary; D005260:Female; D005524:Food Technology; D008297:Male; D008460:Meat / Q000032:analysis* / Q000592:standards*; D018482:Muscle, Skeletal / Q000737:chemistry / Q000201:enzymology / Q000502:physiology; D013997:Time Factors; D014481:United States; D016885:United States Department of Agriculture
chemical_list: D002135:Calcium-Binding Proteins; C033668:calpastatin; D002154:Calpain