Lean Meat Colour Research Articles

Colour variability of beef in young bulls from fifteen European breeds

SummaryThe objective of this study was to determine the variation of the colour of longissimus thoracis muscle within and among fifteen European cattle breeds reared under comparable management conditions. A total of 436 unrelated purebred young bulls from fifteen European breeds (Aberdeen Angus, Highland, Jersey, South Devon, Danish Red, Holstein, Simmental, Asturiana de las Montañas (also known as Casina), Asturiana de los Valles, Avileña‐Negra Ibérica, Pirenaica, Marchigiana, Piemontese, Charolais and Limousin) were reared in five experimental research centres in the United Kingdom, Denmark, Spain, Italy and France. The pH of M. longissimus thoracis was measured at 24 h and after 10 days of ageing and colour at 48 h and 10 days. Two generalised linear models, Pearson correlations and a hierarchical cluster analyses were carried out. Lean meat colour differed significantly between breeds, and these fifteen European breeds could be grouped according to four classes of commercial interest: ‘very bright and pale‐red’, ‘bright and pale’, ‘red’ and ‘dark and dull red’. These groups were partially related to body size and carcass traits, fatness and muscle development and structure, and were controlled by differences in gene expression within each breed.

Genome-Wide Association of Myoglobin Concentrations in Pork Loins

Lean color is a major focus for identifying pork loins for export markets, and myoglobin is the primary pigment driving pork color. Thus, increasing myoglobin concentration should increase redness of pork products and the number of loins acceptable for exportation. Therefore, understanding genetic variation and parameters affecting myoglobin concentration is critical for improving pork color. The objective of this study was to identify genetic markers associated with myoglobin concentration in pork loin muscle. Ultimate pH and myoglobin concentrations were measured in longissimus thoracis et lumborum samples of pigs (n = 599) from two different commercial finishing swine facilities. A Bayes-C model implemented in GenSel identified regions within 7 chromosomes that explained greater than 63% of the genetic variance in myoglobin concentration. Chromosome 7 had 1 significant region which accounted for 37% of the genetic variance, while chromosome 14 had 4 significant regions accounting for 9.8% of the genetic variance. Candidate genes in the region on chromosome 7 were involved in iron homeostasis, and genes in the significant regions on chromosome 14 were involved in calcium regulation. Genes identified in this study represent potential biomarkers that could be used to select for higher myoglobin concentrations in pork, which may improve lean meat color.

042 Genome-wide association of myoglobin concentrations in pork loins

Lean color is a major focus for identifying pork loins for export markets, and myoglobin is the primary pigment driving pork color. Thus, increasing myoglobin concentration should increase redness of pork products and the number of loins acceptable for exportation. Therefore, understanding genetic variation and parameters affecting myoglobin concentration is critical for improving pork color. The objective of this study was to identify genetic markers associated with myoglobin concentration in pork loin muscle. Ultimate pH and myoglobin concentrations were measured in longissimus thoracis et lumborum samples of pigs (n = 599) from two different commercial finishing swine facilities. A Bayes-C model implemented in GenSel identified regions within 7 chromosomes that explained greater than 63% of the genetic variance in myoglobin concentration. Chromosome 7 had 1 significant region which accounted for 37% of the genetic variance, while chromosome 14 had 4 significant regions accounting for 9.8% of the genetic variance. Candidate genes in the region on chromosome 7 were involved in iron homeostasis, and genes in the significant regions on chromosome 14 were involved in calcium regulation. Genes identified in this study represent potential biomarkers that could be used to select for higher myoglobin concentrations in pork, which may improve lean meat color.

Polymorphisms in epigenetic and meat quality related genes in fourteen cattle breeds and association with beef quality and carcass traits.

Improvement for carcass traits related to beef quality is the key concern in beef production. Recent reports found that epigenetics mediates the interaction of individuals with environment and nutrition. The present study was designed to analyze the genetic effect of single nucleotide polymorphisms (SNPs) in seven epigenetic-related genes (DNMT1, DNMT3a, DNMT3b, DNMT3L, Ago1, Ago2, and HDAC5) and two meat quality candidate genes (CAPN1 and PRKAG3) on fourteen carcass traits related to beef quality in a Snow Dragon beef population, and also to identify SNPs in a total of fourteen cattle populations. Sixteen SNPs were identified and genotyped in 383 individuals sampled from the 14 cattle breeds, which included 147 samples from the Snow Dragon beef population. Data analysis showed significant association of 8 SNPs within 4 genes related to carcass and/or meat quality traits in the beef populations. SNP1 (13154420A>G) in exon 17 of DNMT1 was significantly associated with rib-eye width and lean meat color score (p<0.05). A novel SNP (SNP4, 76198537A>G) of DNMT3a was significantly associated with six beef quality traits. Those individuals with the wild-type genotype AA of DNMT3a showed an increase in carcass weight, chilled carcass weight, flank thicknesses, chuck short rib thickness, chuck short rib score and in chuck flap weight in contrast to the GG genotype. Five out of six SNPs in DNMT3b gene were significantly associated with three beef quality traits. SNP15 (45219258C>T) in CAPN1 was significantly associated with chuck short rib thickness and lean meat color score (p<0.05). The significant effect of SNP15 on lean meat color score individually and in combination with each of other 14 SNPs qualify this SNP to be used as potential marker for improving the trait. In addition, the frequencies of most wild-type alleles were higher than those of the mutant alleles in the native and foreign cattle breeds. Seven SNPs were identified in the epigenetic-related genes. The SNP15 in CAPN1 could be used as a powerful genetic marker in selection programs for beef quality improvement in the Snow Dragon Beef population.

Novel single nucleotide polymorphisms of the bovine methyltransferase 3b gene and their association with meat quality traits in beef cattle

DNA methylation is essential for adipose deposition in mammals. We screened SNPs of the bovine DNA methyltransferase 3b (DNMT3b) gene in Snow Dragon beef, a commercial beef cattle population in China. Nine SNPs were found in the population and three of six novel SNPs were chosen for genotyping and analyzing a possible association with 16 meat quality traits. The frequencies of the alleles and genotypes of the three SNPs in Snow Dragon beef were similar to those in their terminal-paternal breed, Wagyu. Association analysis disclosed that SNP1 was not associated with any of the traits; SNP2 was significantly associated with lean meat color score and chuck short rib score, and SNP3 had a significant effect on dressing percentage and back-fat thickness in the beef population. The individuals with genotype GG for SNP2 had a 25.7% increase in lean meat color score and a 146% increase in chuck short rib score, compared with genotype AA. The cattle with genotype AG for SNP3 had 35.7 and 24% increases in dressing percentage and 28.8 and 29.2% increases in back-fat thickness, compared with genotypes GG and AA, respectively. Genotypic combination analysis revealed significant interactions between SNP1 and SNP2 and between SNP2 and SNP3 for the traits rib-eye area and live weight. We conclude that there is considerable evidence that DNMT3b is a determiner of beef quality traits.

Effect of Postmortem Metabolic Rate on Meat Color

The current study was conducted to evaluate carcass characteristics, objectives and sensory meat qualities of Hanwoo longissimus muscle as affected by ultimate pH. Twenty-four steers and bulls (556±53 kg and 0.63±0.32 cm for live weight and backfat thickness, respectively) were used. As there was a linear relationship (r = 0.77) between lean meat color and ultimate pH, cattles were thus segregated into normal (pH 5.8, n = 11) groups. Normal pH group had significantly (p<0.05) higher carcass weight, marbling score and backfat thickness than those for high pH group, while fat color and lean meat color were inverse. In principle component analysis for co-ordinates of DFD and normal meats, fat color, lean meat color, texture, time to pH 6.2 and pH at 24 h postmortem were associated with the positive range of the first factor (67.5%) while backfat thickness marbling score and temperature at 24 h were placed in negative values. The rate constant of decline in pH (pH k) did not differ between the two groups, implying that initial pH (i.e., pH at slaughtering) differed between two groups. Contour mapping of pH k between pH at 1 and 24 h postmortem indicated that high pH k was related to lower pHs at 1 and 24 h postmortem. This suggested that the high pH cattles (i.e., DFD cattle) resulted from their own potential. Although the time to reach pH 6.2 was significantly (p<0.05) shorter for normal meat (i.e., 3.2 h) than that for DFD one (i.e., 19.8 h), there were no significantly differences in both WB-shear force and sensory attributes. Given that the experimental animals were sampled from a similar group, which implies a similar myoglobin pigment content, the current data suggested that pre- and post-slaughter animal handling likely had a significant effect on ultimate pH and consequently meat color of Hanwoo longissimus muscle, and also small animals with lower marbling score and backfat thickness had a higher risk for DFD meat.

Consumer assessment of the effect of electrical stimulation on the colour and colour stability of Semimembranosus muscles

The influence of effective low voltage electrical stimulation on the colour stability of beef topside ( semimembranosus) muscles, during storage and retail display was studied using objective measurements and subjective assessments. Earlier results obtained from objective measurements demonstrated that during a three day retail display period, stimulated topsides had a greater loss of colour than non-stimulated topsides, and primal cuts aged for 33 days at 0 °C before display suffered faster changes to colour during retail presentation than cuts aged for 5 days. To relate results obtained using objective methods to consumer perceptions of meat quality, consumer perceptions of samples of meat displayed for 3 days in the retail cabinets of a major local supermarket were recorded. A total of 960 consumers were asked to evaluate topside steaks for meat and fat colour, meat discolouration and acceptability. During 3 days of retail display, consumers did not perceive differences in the extent of discolouration of topside steaks from electrically stimulated and non-stimulated carcasses; for the majority of the treatment groups (high or low pH muscles, 5 or 33 day ageing, 1–3 day retail display) there were no significant differences, for any of the scored attributes, between stimulated and non-stimulated samples. However, for samples in the fresh (5 days ageing), high pH (5.8–6.0) treatments group, lean meat colour and acceptability for the stimulated samples were, on some of the days on display, given significantly ( P < 0.05) better ratings by the consumers than those from corresponding non-stimulated samples.

The retail display life of steaks prepared from chill stored vacuum and carbon dioxide-packed sub-primal beef cuts

Chilled striploins and cube rolls from ten Australian steers (grain-fed for 150 days) were trimmed of external fat and cut transversely into portions approximately 10 cm thick, each weighing between 750 and 1000 g. These ‘retailer-ready’ cuts were each wrapped in drip saver pads and slid inside a plastic sleeve before being individually placed into a clear plastic high oxygen barrier film, metallized film or conventional vacuum bag. Cuts in clear plastic and metallized film packs were packaged in an oxygen-free saturated carbon dioxide atmosphere ( CO 2 -CAP), those in vacuum bags were conventionally vacuum-packed. All packs were returned to the chiller for further cooling. After 24 hr, half the clear plastic and metallized CO 2 -CAP packs were carbon dioxide master-packed in groups of eight. Retailer-ready cuts in both clear plastic and metallized film single unit and master-packed CO 2 -CAP packs were air freighted to New Zealand and sea freighted to Japan for assessment. The control vacuum packs were all consigned to New Zealand. Assessments in both countries after 39–89 days storage at between 0 °C and −1.0 °C indicated that fat colour stability limited the retail display life of steaks cut from meat in these retailer-ready packs to approximately 48 hr. In this regard, meat from single unit CO 2 -CAP, master pack CO 2 -CAP and vacuum packs performed similarly. Lean meat colour and sensory attributes remained acceptable for up to 48 hr after displayed product was rejected because of grey-green fat discoloration. The microbiological status of retailer-ready cuts removed from CO 2 -CAP packs after 89 days chilled storage was superior to that of cuts from vacuum packs. Clear plastic and metallized film CO 2 -CAP packs performed comparably.

Evaluation of specific populations of commercial pigs produced in Québec for feed performance, carcass yield and lean meat colour

Data from approximately 850 commercial pigs tested in 12 trials, from 1987 to 1990 at the Beaumont test station in Québec were used to determine the effect of growth rate and body composition on growth performance, carcass yield and lean meat colour. Pigs were housed four to a pen and were fed commercial diets. Feed intake and growth rate were measured during the test, and carcass measurements were taken at slaughter and at 24 or 72 h following slaughter. The different groups of pigs were defined according to a 2 × 2 factorial, with one factor being the growth rate [fast growth (FG) or slow growth (SG)] and the second factor being the body composition of the carcass [fat (F) or lean (L)]. The FG commercial pigs reach market weight at a younger age with lower overall feed consumption and generally a better feed conversion than SG pigs. Furthermore, FG pigs have more backfat, longer carcasses and a slightly darker meat. The L commercial pigs had similar growth performances with a better lean meat yield than the F commercial pigs. Growth variables and composition of the carcass had little effect on the meat characteristics measured. The proportion of barrows compared to gilts was higher in the FG and F groups than in the SG and L groups, which could account for some of the differences observed between groups. However, the rate of growth and the type of body composition affected the growth and feed consumption performances as well as the carcass yield in a similar way for both sexes. Overall, less than 3% and less than 2% of the pigs produced meat with a colour standard of 1 (extremely pale) or 5 (extremely dark), respectively. The SG-L group had a slightly higher proportion of pigs with a pale meat colour compared to the other groups. Key words: Pig, backfat, growth rate, carcass composition, meat colour

Evaluation of the lean meat colour of commercial pigs produced in Quebec

Data from a total of approximately 2900 commercial pigs tested in 12 trials from 1987 to 1990 at the Beaumont test station in Quebec were used to determine the effect of sex, sire breed, cross type and parity number of the dam on meat colour. Pigs were housed four to a pen and fed commercial diets. Meat colour measurements were taken 24 h or 72 h after slaughter in a commercial abattoir. The sex of the pigs had no major effect on any of the meat colour measurements. Commercial pigs sired by Hampshire or Hampshire-Duroc boars had characteristics of the loin and ham associated with a paler meat (lower ultimate pH and a higher Luminosity L*) than pigs sired by Landrace, Yorkshire or Duroc boars. A Chi-square analysis of the data indicates that the meat from pigs sired by Hampshire or Hampshire-Duroc boars was more often classified within the colour standards 1 and 2, and less often classified within the colour standards 4 and 5 than the meat from pigs sired by Landrace, Yorkshire or Duroc boars. Four-way cross and especially synthetic cross pigs had a paler meat than single cross, backcross and three-way cross pigs. Overall, less than 3% and less than 1% of the pigs produced meat with a colour standard of 1 (extremely pale) or 5 (extremely dark), respectively. Parity number of the dam did not affect meat colour. A factor analysis and Pearson's coefficients of correlation between the meat colour characteristics indicate that taking the same measurements on both the loin and ham muscle add relatively little information on meat colour. It appears that measuring the pH, the luminosity L* and the chromaticity value a* on either the loin or the ham muscle could be sufficient for an acceptable estimation of meat colour of commercial pigs from the present study. Key words: Pig, meat colour, pH