Chemical composition and cooking properties of beef forequarter muscles of Mexican cattle from different genotypes.

Beef forequarter muscles biceps brachii (BRB), brachialis (BRA), complexus (COM), splenius (SPL), infraspinatus (INF), teres major (TER), rhomboideus (RHO), subscapularis (SUB), supraspinatus (SUP), triceps brachii long-head (TRB) and triceps brachii lateral-head (TRI) were obtained from Mexican beef carcasses originated from Bos indicus (Bi, n=10) or Bos taurus (Bt, n=10) young bulls. Muscles were analyzed for WBSF, cooking loss, and moisture and fat contents. INF had the lowest WBSF (37.23N) and cooking loss (31.78%) of all. RHO exhibited the lowest moisture (72.62%) and highest fat content (5.23%) of all. Bi genotype exhibited higher WBSF (53.78, 48.69N), higher cook loss (36.27, 34.32%), higher fat content (2.93, 2.35%), and lower moisture content (73.70, 75.07%) than Bt. Further research is needed to estimate the actual consumer acceptance of beef forequarter muscles and their marketing potential as individual cuts in the Mexican market.

Effects of genotype, level of supplementation, and organic chromium on growth performance, carcass, and meat traits grazing lambs.

The aim of the present study was to evaluate the effects of Suffolk×Dorper (SD) and Rambouillet (R) lamb genotypes, dietary supplementation, and organic chromium on growth performance, carcass, and meat traits in male lambs grazing ryegrass pasture. SD lambs had heavier cold carcass (HCW) and better carcass yield (CY) and rib eye area at 12th rib (RA) than R lambs; R had larger legs. Feed supplement increased average daily weight gain (ADG), slaughter live weight (SLW), hot carcass weight (HCW) and cold carcass weight (CCW), carcass yield, carcass length (CL), leg perimeter (LP), major thorax width (MTW), minor thorax width (MiTW), rib eye area and dorsal fat at 12th rib (DF12), and also decreased meat moisture. Organic chromium reduced dorsal fat at 12th rib and meat fat content.

Association of CAPN1 316, CAPN1 4751 and TG5 markers with bovine meat quality traits in Mexico.

We examined allele and genotype frequencies for the molecular markers CAPN1 316, CAPN1 4751 and TG5, and determined whether they are associated with beef quality traits in Mexican cattle. One hundred and twenty-four longissimus dorsi muscle samples were collected from cattle from north, central and southern Mexico. CAPN1 316 and CAPN1 4751 frequencies were determined using the allelic discrimination assay and the TG5 marker was typed by PCR-RFLP. Meat quality traits included intramuscular fat content (IMF) and tenderness determined by Warner-Bratzler shear force (WBSF) at 24 h postmortem. The association test was made using a mixed model, including genotypes, genetic group, and sampling location as fixed effects. Least squares means and significant interactions were compared using least significant differences based on the mixed procedure. CAPN1 316 CC was found at a low frequency (0.03) and has been reported as a favorable genotype associated with tenderness meat. Genotype frequencies for CAPN1 4751 were similar in favorable (CC) and unfavorable (TT) genotypes (0.26 and 0.28, respectively). The TG5 CC genotype had a frequency of 0.73, while the TT genotype frequency was 0.01. The means for WBSF and IMF were 4.08 ± 1.35 kg and 5.23 ± 2.14%, respectively. Sampling site and the CAPN1 316 genotypes significantly affected WBSF (P < 0.05). Samples collected from Hermosillo, Sonora, had the lowest WBSF (P < 0.05), while those collected in Veracruz were toughest (WBSF = 5.267 kg). The effect of GG and TG5 genotypes on IMF was significant (P < 0.05). CAPN1 316 and TG5 markers were found to be significantly associated with beef quality traits and thus will be useful for Mexican beef characterization.

A survey of beef carcass quality and quantity attributes in Mexico.

The objective of the present study was to evaluate quality and yield attributes of Mexican beef carcasses to serve as a benchmark for production in the Mexican beef cattle industry. Seven packing plants were surveyed nationwide. Carcass yield and quality traits were assessed in the cooler at approximately 24 h postmortem. Results indicated that around 90% of the beef slaughter population in Mexico has a strong Bos indicus genetic background. Moreover, 71.6% of the surveyed cattle are presented for slaughter at a BW between 400 and 500 kg. Chilled carcass weight was between 220 and 340 kg in 88.9% of the surveyed population. According to European beef carcass grading standards, carcass conformation varied from poor to good in 82% of the carcasses, whereas in 17.8% the conformation was very good or excellent. In 60.7% of the surveyed carcasses the KPH was 2% or less. The subcutaneous fat depth was 1 cm or less in 90% of the carcasses. In 71.8% of the carcasses the LMA was of 80 cm(2) or less, whereas only 8.6% had LMA values of 90 cm(2) or greater. Carcass maturity score USDA B(100) or less was found in 92.4% of the evaluated carcasses, whereas 28.5% were graded as USDA A(100)/B(00). A total of 93.6% of the sample had marbling scores of 300 or less, corresponding to the categories slight, practically devoid, or traces. Only 12.9% of the carcasses exhibited a yellow fat cover. In the remaining 87.1% the fat cover was white or beige. The backfat layer was uniform in 43.2% of the carcasses, whereas 55.9% had an uneven fat cover. Information from this survey provided data that could serve as a means to develop a yield and quality evaluation program that can be further developed into a value system for Mexican beef carcasses and live cattle.

Mechanical and functional properties of beef products obtained using microbial transglutaminase with treatments of pre-heating followed by cold binding.

Beef proteins are considered non-setting proteins and usually gels obtained by adding of microbial transglutaminase are obtained by cooking directly the solubilized paste. The aim of this work was to determine the effect of pre-heating treatments on the mechanical properties of restructured beef gels treated with microbial transglutaminase (MTG). The effect of cooling (cold binding) the solubilized pastes after the pre-heating treatments was also studied. The restructured beef gels were obtained by adding 0.3% MTG or 0% MTG (control). Three pre-heating temperatures (40, 50 or 60°C) for 30 or 60min were studied, followed by heating at 90°C for 15min. Control samples without pre-heating were also prepared. Cold binding was studied by holding pre-heated gels at 4°C for 12h before heating at 90°C for 15min. Changes in mechanical properties (texture profile analysis and puncture test), color attributes, expressible water and cooking loss were determined. Results indicated that the better mechanical properties can be obtained by pre-heating beef pastes at 50°C for 30min with minimal effect on color, expressible water and cooking loss when 0.3% of MTG is added. It was concluded that there were no practical advantages by pre-heating the gels for 60min. Cold binding did not improve the mechanical properties of beef gels.

Composition and quality of Mexican and imported retail beef in Mexico.

Randomly selected New York steaks from domestic and imported beef were purchased in three major Mexican cities, comparing Mexican beef (from northern, central, and southern regions of the country) and American beef (USDA-Choice and ungraded No Roll). The meat was analyzed for chemical composition, Warner-Bratzler shear force (WBSF), cooking loss, color and consumer acceptability. All sources of Mexican beef and No Roll US beef had similar chemical composition. USDA-Choice beef had a higher fat content and a lower moisture and total collagen content. Mexican beef from the northern region and USDA-Choice beef had lower WBSF and redness values than the other beef sources. Overall desirability was high regarding all Mexican beef sources, and USDA-Choice beef. No Roll US beef had the lowest overall desirability score. Results indicate Mexican beef is in an advantageous position when competing with imports in the current open market.

Effects of crossbreeding Mexican Pelibuey sheep with Rambouillet and Suffolk on carcass traits.

Fifty nine lambs: Pelibuey (P), Suffolk×Pelibuey (SP) and Rambouillet×Pelibuey (RP), were used to evaluate the effect of crossbreeding on carcass characteristics and composition. Following carcass evaluation, muscle, bone, subcutaneous, seam, internal, total fat and other tissues were dissected. Carcass dressing percentage was similar across the three genotypes. The genetic group did not influence the percentage of cuts, except for shoulder percentage. Pelibuey carcasses had less fat thickness than RP and more kidney, pelvic and heart fat than SP. Muscle percentage was lower for RP (51.27±0.68) compared to P (54.01±0.61) and SP (53.78±0.58) carcasses, respectively. Consequently, the RP group showed the highest proportion of total fat (19.66±1.00). In general, RP carcasses had the lowest meat cutability. In conclusion, carcass yield of Pelibuey lambs was not improved by the cross with either Rambouillet or Suffolk breeds.

Composition and sensory evaluation of lamb carcasses used for the traditional Mexican lamb dish, "barbacoa".

The objective of this study was to determine the differences in carcass characteristics and sensory attributes of "barbacoa" (a traditional Mexican lamb dish), both of imported (New Zealand) and domestic lambs in Mexico. A total of 28 carcasses from Pelibuey, Pelibuey×Suffolk and imported lambs were used. Carcass composition was determined by dissection of primal cuts from the left half of each carcass. The "barbacoa" from each ovine group was prepared separately in order to perform a consumer sensory evaluation for aroma, taste and tenderness. Results showed that imported lambs had larger carcasses, greater fatness and had better conformation than national lambs. There was no difference between groups in terms of lean tissue percentage (muscle+others) or in total carcass fat. The sensory attributes of the "barbacoa" did not differ among breeds. Pelibuey lambs (rustic, prolific and adaptable to the wide variety of Mexican climates) show competitive production performance in relation to specialized breeds.