Effect of different gas stunning methods on Manchega suckling lamb meat packed under different modified atmospheres

Forty-nine Manchega breed male suckling lambs were used in this experiment. The effect of CO₂ concentration and exposure time at stunning [80% CO₂ for 90 s (G1); 90% CO₂ for 90 s (G2); 90% CO₂ for 60 s (G3); 80% CO₂ for 60 s (G4)] plus an electrically stunned control group (G5) was assessed for pH, colour (L^∗, a^∗, b^∗, C^∗ and h^∗), water holding capacity (WHC), drip loss (DL), cooking loss (CL) and shear force (SF) in samples packed under two different types of modified atmospheres (MA: MA A: 70%O₂ + 30%CO₂; MA B: 69.3%N₂ + 30%CO₂ + 0.7%CO) at 7, 14 and 21 d post-packaging. The lowest pH was found in G4 and in G5. The highest WHC and the lowest CL were found in G2 and G3 groups (P < 0.05). Modified atmospheres did not affect on pH, WHC, CL and DL, although a significant effect (P < 0.001) on colour was found at all the analysis times. Both the type of stunning and the modified atmosphere affected SF values.     

Ability of near infrared reflectance spectroscopy (NIRS) to estimate physical parameters of adult steers (oxen) and young cattle meat samples

The potential of NIRS-based models to predict several physical parameters of oxen and young cattle beef protected by a quality mark was evaluated. Fifty-three and 67 samples of Longissimus thoracis muscle corresponding to oxen and young cattle reared in extensive conditions were analyzed for pH, colour (L^∗, a^∗, b^∗), water holding capacity (WHC) and Warner–Braztler shear force (WBSF), according to the conventional methods. Several factors which might have jeopardized the prediction of pH, a^∗, WHC and WBSF by NIRS are considered in the discussion section. However, the best NIR calibrations, tested by full cross-validation, were for L^∗ (R² = 0.869; SE_CV = 1.56) and b^∗ (R² = 0.901; SE_CV = 1.08) colour parameters in meat samples from young cattle. It can be concluded that NIRS could be a useful tool for estimating the colour of young cattle meat samples, primary consideration for consumers when making purchasing decisions.     

Influence of carbon monoxide in package atmospheres containing oxygen on colour, reducing activity, and oxygen consumption of five bovine muscles

Steaks from five bovine muscles [psoas major (PM), longissimus lumborum (LL), deep semimembranosus (DSM), superficial semimembranosus (SSM), and semitendinosus (ST)] were packaged in atmospheres containing 20% or 80% oxygen, with and without 0.4% carbon monoxide. Steaks were evaluated on d 0, 4, and 7 of retail display for instrumental (CIE L^∗, a^∗, and b^∗) and visual colour, total- and metmyoglobin-reducing activity, and oxygen consumption rate. Combining carbon monoxide with either oxygen level had no effect (P > 0.05) on any measured attribute. Using higher oxygen levels increased colour stability and reduced variability (P < 0.05) among muscles for all measured attributes. In general, colour stability and reducing activity for the muscles were LL > ST > SSM > PM > DSM. Including 0.4% carbon monoxide with 20% or 80% oxygen may not have impacted colour, due to preferential formation of oxymyoglobin, rather than carboxymyoglobin, at these oxygen levels.     

Effects of ascorbic and citric acid on beef lumbar vertebrae marrow colour

Citric acid was evaluated as a way of improving ascorbic acid’s ability to stabilize beef lumbar vertebrae colour in high-oxygen packaging (MAP; 80% O₂/20% CO₂). Vertebrae were treated with citric acid (1%, 3%, or 10%), ascorbic acid (1%, 3%, or 10%), or a combination of both. Citric acid demonstrated no positive effects (P > 0.05), compared with ascorbic acid, which inhibited (P < 0.05) discolouration throughout the 7d display. Although ascorbic acid inhibited discolouration (visual colour and a^∗; P < 0.05), 3% and 10% ascorbic acid were most effective. However, if vertebrae are displayed for less than 7d, there may be no significant colour-stabilizing advantages associated with increasing ascorbic acid from 3 to 10%. The significant oxidizing effects of citric acid at 10% were reversed (P < 0.05) by ascorbic acid. Combining citric and ascorbic acid had no synergistic affect (P > 0.05) on vertebrae colour.     

Effects of stunning with different carbon dioxide concentrations and exposure times on suckling lamb meat quality

Forty-nine Manchega breed male suckling lambs were used to determine the effect of different stunning methods (using two different CO₂ concentrations and exposure times) on lamb meat quality. The lambs were allocated to five stunning treatments including four CO₂ treatments [80% CO₂ for 90 s (G1); 90% CO₂ for 90 s (G2); 90% CO₂ for 60 s (G3); 80% CO₂ for 60 s (G4)] and an electrically stunned control group (G5). The gas-stunning treatments did not cause neither haematomas nor blood splash in the carcasses. Meat quality was evaluated by testing pH, colour (L^∗, a^∗, b^∗, chroma, hue values), water holding capacity (WHC), cooking loss (CL), shear force (SF), drip loss (DL) and total aerobic bacteria. Statistical differences in pH at 24 h post-mortem, colour, WHC and CL were not found among groups. After 7 days post-mortem, there were statistical differences among groups in pH (highest in G4 and G5) and in DL (highest in G1). There were differences in SF due to stunning method evident after 72 h and 7 days ageing. The statistical differences (P < 0.01) among groups on total aerobic bacteria at 24 h (lower and higher values in G2 and G5, respectively) disappeared at 7 days post-mortem. As G2 as G3, could be recommended to stunning suckling lambs since a highest stability with ageing time on meat quality was found using 90% CO₂.     

Influence of vacuum-aging period on bloom development of the beef gluteus medius from top sirloin butts

The gluteus medius (GM) from USDA Select beef carcasses was used to test the effect of aging period on bloom development. Top sirloin butts (IMPS #184) were randomly allocated to 0, 7, 14, 21, 28, and 35 d vacuum-aging at 2 °C (n = 10/aging period). Each week, aged top sirloin butts were faced before two 2.5-cm-thick, non-adjacent steaks were cut and instrumental color (L^∗, a^∗, and b^∗) of the GM was measured at 10-min intervals for 2 h after cutting. Steaks aged for 7 and 14 d were a more vivid (greater chroma values; P < 0.05), redder (greater a^∗ values; P < 0.05), and more yellow (greater b^∗ values; P < 0.05) color than steaks from the other aging periods. Change in total color (ΔE) was greater (P < 0.05) for steaks from top sirloin butts aged 7, 14, and 21 d than steaks from top butts aged 28 and 35 d, whereas oxymyoglobin percentages for steaks from top butts aged 7 and 14 days were greater (P < 0.05) than those from top sirloin butts aged 28 and 35 d. As much as 90% of the total increase (P < 0.05) in a^∗, b^∗, and chroma values, as well as hue angles and oxymyoglobin percentages, was achieved during the first 60 min after cutting.     

CO2 stunning procedure on Manchego light lambs: Effect on meat quality

This study examined the effect of different gas stunning methods (concentration of CO₂/time of exposure (G1: 80%90s; G2: 90%90s; G3: 90%60s; G4: 80%60s) on the initial meat quality of Manchego breed light lambs (25 kg live weight) and at 7 days post-mortem, assessed by pH, colour coordinates, water holding capacity (WHC), cooking loss (CL), drip loss (DL) shear force (SF) and lipid oxidation. An electrically stunned control group (G5) was used. Stunning method had a significant effect on pH values (P < 0.001) as well as on pH decline (P < 0.01). The lowest pH was found at 24 h post-slaughter in G1 and the highest one on G5. The greatest drop in pH (pH₀–pH₂₄) was found in G1 and G5 while the smallest in G3. In general values of colour coordinates, WHC and DL were similar in all groups. Stunning method affected CL (P < 0.001) at 7 days post-slaughter, with the lowest values being found in G1. Significant differences among groups were found (P < 0.05) in SF values at both post-mortem times, with less tender meat in groups stunned with 80% CO₂, especially in G1. A significant effect (P < 0.001) due to the type of stunning was found at 24 h on lipid oxidation, with the highest value in G5. After ageing this parameter was lowest (P < 0.05) in G1 and G4.     

Effect of carbon monoxide packaging and lactate enhancement on the color stability of beef steaks stored at 1°C for 9 days

Our objective was to assess the effects of lactate enhancement in combination with different packaging systems on beef longissimus lumborum and psoas major steak color. Strip loins and tenderloins (n = 16) were assigned to one of four injection treatments (non-injected control, water-injected control, 1.25%, and 2.5% lactate in the finished product). Steaks were individually packaged in either vacuum, high-oxygen (80% O₂/20% CO₂), or 0.4% CO (30% CO₂/69.6% N₂) and stored for either 0, 5, or 9 days at 1 °C. The L^∗ and a^∗ values of both the longissimus and psoas responded similarly to lactate, which at 2.5% darkened steaks (P < 0.05) packaged in all atmospheres and improved (P < 0.05) the redness of steaks packaged in high-oxygen. Packaging steaks in CO did not counteract the darkening effects of lactate. Nevertheless, CO improved (P < 0.05) color stability compared with high-oxygen packaging.     

Dietary tannins improve lamb meat colour stability

Fourteen male Comisana lambs were divided into two groups at 45 days of age: lambs fed a concentrate diet (C), or lambs fed the same concentrate with the addition of quebracho (Schinopsis lorentzii) tannins (T). Sheep were slaughtered at 105 days of age. Lipid oxidation, colour coordinates, haem pigment concentration, and metmyoglobin percentages were measured on minced semimembranosus muscle (SM) over 14 days of refrigerated storage in a high oxygen modified atmosphere. Tannin supplementation increased (P < 0.01) a^∗ values and reduced (P < 0.01) b^∗ values of the SM when compared to C. Lower hue angles (P < 0.001) and metmyoglobin formation (P = 0.07) were observed in lamb from T-fed compared to C-fed sheep during the 14-days storage period. Furthermore, feeding T resulted in greater (P < 0.001) haem pigment concentrations in the SM during refrigerated storage; however, diet had no (P = 0.28) effect on lipid oxidation. Therefore, including quebracho tannins in sheep diets can improve meat colour stability of fresh lamb during extended refrigerated storage.     

Comparison of ascorbic acid and sodium erythorbate: Effects on the 24h display colour of beef lumbar vertebrae and longissimus lumborum packaged in high-oxygen modified atmospheres

Sodium erythorbate and ascorbic acid were compared as a means to stabilize surface colour of bone-in beef steaks in high-oxygen modified atmosphere (80% oxygen and 20% carbon dioxide). Bone-in strip loins (n = 8) were fabricated into 1.9 -cm thick steaks, of which both the lumbar vertebrae and longissimus lumborum were topically treated with either ascorbic acid or sodium erythorbate (0, 0.05, 0.1, 0.5, 1.0, or 1.5%, wt/wt basis). Colour (L^∗a^∗b^∗) was evaluated before treatment and 24 h after packaging (display at 1 °C). Sodium erythorbate was as effective as ascorbic acid for inhibiting vertebrae discolouration (P > 0.05). Either reducing agent at 0.5, 1.0, or 1.5% improved (P < 0.05) vertebrae redness (compared with 0%, 0.05% and 0.1%). No detrimental effects on muscle colour were observed. When selecting antioxidants intended for bone-in beef steaks displayed in high-oxygen packaging, sodium erythorbate may be a cost effective substitute for ascorbic acid.     

Effects of dietary supplementation of vitamins D(3) and E on quality characteristics of pigs and longissimus muscle antioxidative capacity

The effects of addition of vitamin D₃ and vitamin E to pig diets on blood plasma calcium concentration, meat quality (longissimus muscle) and antioxidative capacity were investigated. Two treatments consisted of supplementation with vitamin D₃ (500,000 IU/d) for 5 days separately (group D) and a combination of vitamin E (500 mg α-tocopheryl acetate/kg diet) for 30 days and vitamin D₃ (500,000 IU/d) for 5 days (group D + E) to growing-finishing pigs before slaughter. Pigs fed with vitamin D₃ had higher (P < 0.01) plasma calcium concentration compared with control pigs. Dietary supplementation of vitamin E significantly (P < 0.05) increased the concentration of α-tocopherol in meat (longissimus muscle). Vitamin D₃ supplementation resulted in higher (P = 0.07) a^∗ values of loin chops at 5 days of storage. Vitamin D₃ and vitamin E supplementation did not affect other meat quality characteristics or tenderness (quantified by Warner–Bratzler shear force). Antioxidative capacity (measured as MDA production after incubation of longissimus muscle homogenates with Fe²⁺/ascorbate) was improved by vitamin E and partly by vitamin D₃ supplementation.     

Effect of illumination on the display life of fresh pork sausages packaged in modified atmosphere. Influence of the addition of rosemary, ascorbic acid and black pepper

Pork forelegs were used for manufacturing fresh sausages, treated with different natural antioxidants (rosemary, ascorbic acid and black pepper), packaged in 80% O₂ + 20% CO₂ atmosphere and displayed at 2 ± 1 °C under different lightings (darkness, standard fluorescent, low-UV colour-balanced lamp and standard fluorescent plus a UV-filter). Two packs for each treatment were opened every 4 days for subsequent analysis of colour CIE L^∗, a^∗, b^∗, TBARS, microbial psychrotrophic aerobes and sensory discolouration and off-odour. Lighting with standard fluorescent was highly deleterious for sausage display life, which fell from 12 to 8 days due mainly to early discolouration. Inserting a UV-filter extended display life to 12 days, while the use of a low-UV lamp was not effective in protecting from discolouration. Addition of rosemary plus ascorbic acid, in the absence of black pepper, retarded discolouration only in sausages illuminated with the UV-filter, reaching a display life of 16 days, equal to that of sausages maintained in the dark.     

Improvement of shelf-life of buffalo meat using lactic acid, clove oil and vitamin C during retail display

Buffalo meat steaks dipped in either (1) distilled water (control), (2) lactic acid (LA), (3) LA + clove oil (clove), or (4) LA + clove + vitamin C (Vit C) were displayed at 4 ± 1 °C, illuminated by a standard fluorescent lamp. The pH, 2-thiobarbituric acid reactive substances (TBARS), instrumental colour (CIE L^∗, a^∗, b^∗), aerobic plate counts (APC), psychrotrophic counts (PPC), coliform counts and sensory colour and odour were determined up to 12th day of display at 3 days interval. Results showed that, all the treatments have significantly (P < 0.05) reduced the TBARS values compared to control. Among treatments, use of LA + clove has exhibited significantly (P < 0.05) lowest TBARS values throughout display period than others. Buffalo meat steaks treated with either LA + clove or LA + clove + Vit C had significantly (P < 0.05) lower APC, PPC and coliform counts than control or LA treated samples. LA + clove + Vit C treated samples maintained significantly (P < 0.05) higher a^∗ and b^∗ values during display as well as improvement in sensory colour and odour than others. Treatment with either LA + clove or LA + clove + Vit C extended the display life of buffalo meat steaks at 4 ± 1 °C. There appears to be a significant advantage to using LA + clove or LA + clove + Vit C over LA alone.     

The use of visible and near infrared reflectance spectroscopy to predict beef M. longissimus thoracis et lumborum quality attributes

Visible and near infrared reflectance spectroscopy was used to predict pH at 24 h (pH24) post-mortem, sarcomere length (SL), cooking loss (CL), Warner–Bratzler Shear Force (WBSF) and colour parameters (L^∗, a^∗, b^∗) in beef cattle samples. Samples from M. longissimus thoracis et lumborum from 30 bulls were aged at 4 °C for 1, 3, 7 and 14 days and analysed for pH, SL, CL, WBSF and colour. NIRS calibrations for pH24, luminosity at 0 (L^∗t0) and 60 min (L^∗t60) showed good predictability (R² = 0.97, 0.85 and 0.82; SECV = 0.10, 1.16, 1.36, respectively), whereas those related to the rest of the parameters were poorer.     

Instrumental reflectance values of fresh pork are dependant on aperture size

The effect of aperture size on instrumental pork color measurements was studied. Pork longissimus chops (n = 30) were cut, aerobically packaged, and allowed to bloom overnight. Chops were measured once with each of four aperture ports (4.45, 2.54, 1.27, and 0.64 cm diameter) on a HunterLab LabScan. Reflectance values measured with smaller aperture sizes were reduced (P < 0.05) for most visual wavelengths (10 nm intervals), and the percent reduction was greatest in the range of the longer, redder wavelengths. Values for L^∗, a^∗, b^∗, and saturation index were reduced (P < 0.05) with decreasing aperture size under illuminants A, C, and D₆₅. Using illuminant A, hue angle increased (P < 0.05) as aperture size decreased. For illuminants C and D₆₅, hue angles were similar (P > 0.05) for the three largest aperture sizes, but negative a^∗ values found with the smallest aperture size skewed the hue angle data.     

Burdizzo pre-pubertal castration effects on performance, behaviour, carcass characteristics, and meat quality of Holstein bulls fed high-concentrate diets

The effects of Burdizzo pre-pubertal castration on performance, behaviour, carcass, and meat quality of Holstein bulls fed high-concentrate diets were evaluated. Two hundred bulls (8.0 ± 0.42 months old) were randomly assigned to control (CTR) or Burdizzo castration (BURD). After 121 d, ADG, BW, and HCW were greater in CTR animals than in BURD animals, as well as, the agonistic and sexual behaviour. However, carcass fatness and intramuscular LT (longissimus thoracis) fat percentage were greater in BURD animals than in CTR animals. Additionally, CTR animals showed lower L^∗, a^∗, and b^∗ than BURD. The WBSF was smaller (P < 0.01) in BURD than in CTR bulls at all ageing days, and in both treatments decreased (P < 0.01) from 0 to 7 d of ageing. Additionally, at day 0 of ageing, meat from BURD animals showed similar WBSF to meat from CTR bulls after 7 d of ageing. However, 23% of BURD animals did not have a complete testicular atrophy, suggesting that the method of castration was not completely effective.     

Carcass, sensory, fat color, and consumer acceptance characteristics of Angus-cross steers finished on ryegrass (Lolium multiflorum) forage or on a high-concentrate diet

Fall-born Angus-cross steers (n = 30) from 1 of 2 sires, were randomly assigned to either an 85% corn, 7.5% cotton-seed hulls, and 7.5% vitamin/mineral/urea supplement diet (GRAIN), 100% ryegrass grazing (RG), or ryegrass grazing then the GRAIN diet for 94 d (RG/GRAIN). USDA Yield Grade of steers finished on either the GRAIN or RG/GRAIN regimens were higher (P < 0.02) compared to those finished on RG. Marbling score and USDA Quality Grade did not differ (P = 0.21 and 0.12, respectively) among the three finishing regimens. Yellowness (b^∗) values of the subcutaneous fat from both strip loins (SL) and ribeye (RE) rolls was lowest (P < 0.05) in cuts taken from steers finished on GRAIN. Subcutaneous fat of both SL and RE had lower L^∗ and hue angle values, and higher a^∗ and b^∗ values before trimming than after the fat was trimmed to 0.3 cm. Initial and sustained tenderness scores of SL from steers finished on GRAIN were higher when compared to RG/GRAIN or RG regimens (P < 0.05). Flavor intensity and beef flavor scores were higher (P < 0.05) for SL from GRAIN- or RG/GRAIN-finished steers compared to RG-finished steers. GRAIN SL had lower (P < 0.05) WBSF values than RG, but similar (P > 0.05) to RG/GRAIN. Trained sensory tenderness and flavor scores and WBSF values for RE were not affected by finishing regimen (P > 0.05). GRAIN steaks had a higher consumer overall acceptability score, average price/kg, and rank (P < 0.05). While carcass, fat, and sensory disadvantages were present in RG cattle, the overall magnitude of the differences compared to GRAIN cattle was fairly small.     

Suitability of Norwegian short-tail lambs, Norwegian dairy goats and Cashmere goats for meat production - Carcass, meat, chemical and sensory characteristics

Six female Norwegian lambs (29 kg body weight, 8 months old), six castrated Norwegian goats (27 kg body weight, 10 months old) and six castrated Cashmere goats (20 kg body weight, 8 months old) were used to study the relative potential of Norwegian lambs, Norwegian goats and Cashmere goats for meat production. Animals were fattened on silage and commercial concentrate before slaughter. Lamb meat had 4 % lower (P < 0.05) proteins and 13% higher (P < 0.05) fat content than goat meats. Moreover, m. longissimus dorsi samples from lambs were less red (a^∗) (P < 0.05) and had lower colour intensity (C) and wider hue angle (H) than that from goats. Meat from lambs and Cashmere goats had higher proportions of saturated fatty acids (SFA) (P < 0.001), especially stearic acid and lower ones for total unsaturated fatty acids (TUFA) and monounsaturated fatty acids (MUFA) than the meat from Norwegian goats. Sensory panellists scored lamb meat fattier, juicier and more tender than goat meats. Meat from Cashmere goats scored highest (P < 0.05) in whiteness, and lowest (P < 0.05) in both colour tone and colour intensity. It is concluded that, since C18:0 was the main contributor of SFA in meat from Norwegian lamb and Cashmere goats, meats from them are nutritionally comparable to that from Norwegian goats. However, the higher proportion of SFA in Norwegian lambs and Cashmere goats may increase hardness of fat and being easily solidified upon cooling, may influence meat palatability.     

CT scanning carcases has no detrimental effect on the colour stability of M. longissimus dorsi from beef and sheep

This study investigated the effect of computerised tomography imaging (CT scan), for carcase composition determination, on the oxy/metmyoglobin ratio, hue and L^∗, a^∗ and b^∗ scores of M. longissimus dorsi from both beef and lamb. Beef and lamb M. longissimus dorsi were divided into four proportions and randomly allocated to one of the following treatments; CT 30 day aged; CT fresh; control 30 day aged; control fresh. Colour measurements were made over a 96 h retail display period. CT scan had little effect on the colour of both lamb and beef across all colour parameters. There was a small negative affect observed in CT aged samples (P < 0.05) for ratio, hue, a^∗ and b^∗ values, however these differences were so small that they are unlikely to impact upon the commercial shelf-life of the product. Other factors such as aging, species and vitamin E concentration play a much greater role in colour stability than CT. Aged M. longissimus dorsi clearly had a worse colour stability than the fresh packaged samples, while beef was a lot more colour stable than lamb. It appears that CT scan for the purpose of body composition determination will not have any commercially relevant impact on colour stability of both beef and lamb.     

Colour stability of steaks from large beef cuts aged under vacuum or high oxygen modified atmosphere

The aim was to investigate the effects of ageing large beef cuts, 10-cm-long longissimus dorsi (LD) and 4-cm-long semimembranosus (SM), on colour stability during subsequent storage of steaks in air for 5 days. Ageing solely in high oxygen modified atmosphere (MA, 80% O₂ + 20% CO₂) for 5 or 10 days or ageing in vacuum for 5 or 15 days followed by high oxygen MA for 5 or 10 days were compared with ageing in vacuum for 5, 15 and 25 days at 4 °C. Ageing system and ageing time influenced colour stability. For short ageing times, 5 to 10 days, large beef cuts could be aged in high oxygen MA without negative effect on colour stability compared with vacuum ageing. Longer ageing times, 15 to 25 days, decreased colour stability. Then vacuum ageing was preferable to ageing in vacuum for 5 or 15 days followed by high oxygen MA.