Effects of biological type and dietary fat treatment on factors associated with tenderness: I. Measurements on beef longissimus muscle

Abstract

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.

Postweaning growth and carcass traits in crossbred cattle from Hereford, Angus, Norwegian Red, Swedish Red and White, Friesian, and Wagyu maternal grandsires1,2

“…Several studies have indicated that Angus cattle were similar to Wagyu in production of marbling (Lunt et al, 1993;Mears et al, 2001;Pitchford et al, 2002;Wertz et al, 2002;Wheeler et al, 2004). However, Wagyu cattle deposit more intramuscular fat than other breeds, such as Hereford or Limousin (Mir et al, 1999;Myers et al, 1999;Pitchford et al, 2002;Kuber et al, 2004;Wheeler et al, 2004). Animals with Hereford and Angus inheritance were evaluated as a single group (British Breed) in the current study, and they had similar marbling compared with animals with Wagyu inheritance.…”

“…Mears et al (2001) reported that when comparing crossbred cattle, Hereford × Charolais and Hereford × Simmental animals were heavier at slaughter than were Wagyu crossbred animals. Kuber et al (2004) found that Limousin purebred cattle were heavier than Wagyu × Limousin animals, and these were heavier than purebred Wagyu animals. Wheeler et al (2004) indicated that Wagyusired cattle had the lightest live weight at slaughter.…”

“…In some studies, no difference has been observed between European cattle and Wagyu (Lunt et al, 1993;Myers et al, 1999;Wertz et al, 2002); other studies have reported differences (Kuber et al, 2004;Wheeler et al, 2004). Kuber et al (2004) indicated that Limousin produced carcasses with a lower yield grade than Wagyu and Wagyu × Limousin cattle. This would suggest that Limousin would have a better carcass composition; however, the number of observations used by Kuber et al (2004) was small (n = 12).…”

“…Pitchford et al (2002) reported that animals with Hereford, Angus, Limousin, and South Devon inheritance had heavier hot carcass weights than did animals with Wagyu inheritance. Kuber et al (2004), comparing Wagyu purebred to Limousin and a crossbred between these 2 breeds, found that crossbred cattle had a heavier hot carcass weight than Wagyu, and Limousin cattle had heavier hot carcass weights when compared with the crossbred and Wagyu cattle. Wheeler et al (2004) also reported that Hereford-and Angus-sired animals had heavier hot carcass weights than Wagyu-sired animals.…”

The Paradox of Toughening During the Aging of Tender Steaks

“…Aging does not occur uniformly in all animals. There are species differences, genetic differences within species, and sex differences that occur during aging (Huff and Parrish 1993; Kuber and others 2004) as well as large variation between individuals. Because aging is primarily the result of enzymatic activity, the amounts and activities of proteases and the condition and isotypic composition of substrate proteins all presumably influence potential degree of tenderization (Ahn and others 2003; Shimada and Takahashi 2003).…”