Effects of biological type and dietary fat treatment on factors associated with tenderness: I. Measurements on beef longissimus muscle.
The objective was to evaluate chemical, mechanical, and sensory attributes associated with tenderness in divergent cattle breeds--Wagyu (W; n = 12), Limousin (L; n = 12) and F1-cross (WxL; n = 12)--fed two dietary treatments (0 or 6% sunflower oil (DM basis)). A randomized complete block repeated measures design in a 3 x 2 factorial arrangement of treatments was used, and effects of breed, diet, block, and associated interactions were tested. Cattle were fed barley-based diets for an average of 259 d. Twenty-four hours postmortem (PM), steaks from the longissimus muscle (LM) were sliced, vacuum-packaged, aged (1, 3, 7, 14, 28, and 56 d PM) at 2 degrees C, and frozen (-40 degrees C) until analyzed. Wagyu steaks had lower (P < 0.05) Warner-Bratzler shear force (WBSF) values than L steaks across all aging times. At 1 d PM, W steaks required slightly more (P > 0.05) force to shear than WxL or L (0.30 and 0.11 kg, respectively); however, by d 14 PM, W steaks required 0.77 kg less (P < 0.05) force to shear than L. Wagyu steaks received higher (P < 0.05) sensory panel sustained tenderness scores at d 14 PM than L. The pH decline was slower (P < 0.05), and temperature decline more (P < 0.05) rapid, in W carcasses than L or WxL carcasses. Breed and diet did not affect (P > 0.10) free calcium levels (FCL) over time (0, 1, 3, 7, and 14 d PM), 0-h calpastatin activity (CA), d-1 percent collagen (OH-PRO), or d-1 collagen cross-linking (HP). Western blot analysis for the presence of the troponin-T (TNT) 30-kDa fragment, conducted only on samples from steers fed the 0% sunflower oil diet, demonstrated more proteolysis by d 3 PM in L than W or WxL. Overall, breed differences in mechanical and sensory measures of tenderness were not explained by FCL, CA, OH-Pro, and HP. Even though the initial appearance of the TNT 30-kDa fragment was greater in L, linear slopes for appearance of TNT degradation product across aging time were greater for W and WxL (P < 0.01 and P = 0.056, respectively) than for L, suggesting that tenderness differences due to breed may have been facilitated by more-rapid proteolytic degradation over time.
Kuber
P S
PS
Washington State University, Pullman 99163-6310, USA.
Busboom
J R
JR
Huff-Lonergan
E
E
Duckett
S K
SK
Mir
P S
PS
Mir
Z
Z
McCormick
R J
RJ
Dodson
M V
MV
Gaskins
C T
CT
Cronrath
J D
JD
Marks
D J
DJ
Reeves
J J
JJ
D000818:Animals; D001823:Body Composition / Q000187:drug effects; D002118:Calcium / Q000097:blood; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002417:Cattle / Q000235:genetics / Q000254:growth & development*; D003094:Collagen / Q000032:analysis; D003258:Consumer Behavior; D003433:Crosses, Genetic; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage* / Q000378:metabolism; D005524:Food Technology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008460:Meat / Q000592:standards*; D018482:Muscle, Skeletal / Q000378:metabolism*; D010858:Pigmentation; D010938:Plant Oils / Q000008:administration & dosage* / Q000378:metabolism; D011897:Random Allocation; D000074242:Sunflower Oil; D013696:Temperature; D013997:Time Factors; D020107:Troponin T / Q000378:metabolism
D002135:Calcium-Binding Proteins; D004042:Dietary Fats, Unsaturated; D010938:Plant Oils; D000074242:Sunflower Oil; D020107:Troponin T; C033668:calpastatin; D003094:Collagen; D002118:Calcium