RELATIONSHIP OF CHILLING RATE AND LOCATION WITHIN MUSCLE ON THE QUALITY OF HAM AND LOIN MUSCLES

Halothane negative Durocs (n=36) were slaughtered, and subjected to: accelerated chill (AC: −30C for 2 h, with air circulation, followed by equilibration at 4C for 20–22 h), conventional chill (CC: 4C for 22–24 h with water sprayed every 2 h until 12 h postmortem), and slow chill (SC: 10–12C for 12 h followed by equilibration at 4C for 10–12 h). Color, pH, and drip loss were determined for the Semimembranosus (SM) Biceps femoris (BF) , Longissimus thoracis (LT), and Longissimus lumborum ( LL). In the ham muscles, AC decreased b* values and drip loss. Decreased drip loss was restricted to the outer sites. Ham muscles were darkest in the mid location and lightest in the inner locations. In the Longissimus, AC decreased pH but did not affect color or drip loss. Compared to SC, AC proved beneficial, however, AC had no advantages over CC in pigs with minimal predisposition to quality problems.     

马肉不同部位的品质特性分析

研究不同部位马肉的理化性质,为建立马肉品质评价标准提供参考.选用新疆伊犁马胴体,分别取肩肌、臀肌和背最长肌作为实验材料,并-18℃条件贮存对其化学成分、pH值、肉色、嫩度、解冻滴水损失率、蒸煮损失率、系水力和胶原蛋白进行测定.结果显示,在不同的部位间,水分、粗脂肪、解冻滴水损失率、蒸煮损失率和系水力有极显著差异(P＜0.01); pH值和肉色有显著的差异(P＜0.05).不同部位对水分、粗脂肪、解冻滴水损失率、蒸煮损失率和系水力影响较大.其中背最长肌的水分含量高,解冻滴水损失率、蒸煮损失率和系水力较小,粗脂肪、胶原蛋白的含量和pH值较高;背最长肌肉色鲜艳,肉嫩度较高,是为理想的食用部位.     

Effect of pre-slaughter physiological conditions on the oxidative stability of colour and lipid during chill storage of sliced, retail packed roast ham

Pre-slaughter physiological conditions (A serving as control, B subjected to treadmill exercise immediately prior to stunning, C epinephrine injection 15 h prior to slaughter, and D epinephrine injection 15 h prior to slaughter and subjected to treadmill exercise immediately before stunning) were found to significantly affect colour and lipid oxidation of sliced, retail packed roast ham, produced from nitrite-cured (78 ppm nitrite) M. Longissimus dorsi. The pre-slaughter treatment resulted in variations in the level of glycogen, lactate, ATP and IMP and pH development as monitored in Longissimus dorsi muscles, with the lowest ultimate pH (pH(u)) in muscles from non-epinephrine treated pigs (treatments A and B). The initial tristimulus L(?)-value and the L(?)-value during chill storage of sliced roast ham packed in laminates with low or with very low oxygen transmission rate (OTR=40 and <0.5 cm(3)/m(2)/atm/24 h, respectively) were significantly affected by treatment, although the effect of the treatments was different during storage for 28 days (interaction between treatment and storage time). Roast ham from treatments A and B generally had a paler appearance (higher L(?)-values) than from treatments C and D. No differences in the initial tristimulus a(?)-values (redness) were found. During chill storage, a pronounced colour fading (decrease in a(?)-values) was seen for laminate with low OTR, with a tendency of better colour stability for treatment C than A, but with no differences for the other treatments. For laminates with very low OTR, the cured meat pigment was stable with no decreases in a(?)-values during storage. Lipid oxidation (thiobarbituric acid reactive substances, TBARS) in products in laminates with low OTR increased during storage and was significantly higher for roast ham from non-epinephrine treated pigs (A and B) than for ham from epinephrine-treated pigs (C and D). Statistical analysis relating pH and the level of glycogen, lactate, creatine phosphate, ATP and IMP in the individual pigs to the product quality parameters revealed that the ultimate level of lactate was the most important single parameter affecting product quality. After 28 days of chill storage, roast ham from pigs subjected to treatments C and D were more likely to support bacterial growth than from treatments A and B. In conclusion, the results show that pre-slaughter physiological conditions are of importance for chemical as well as for microbiological changes in retail stored roast ham.     

Investigation on CAST, CAPN1 and CAPN3 porcine gene polymorphisms and expression in relation to post-mortem calpain activity in muscle and meat quality

This study aimed to detect variability in CAST, CAPN1 and CAPN3 porcine genes and to investigate the effect of CAST and CAPN1 polymorphisms on the activity of native and autolyzed μ-calpain and m-calpain, measured from 1 to 72 h post-mortem in Longissimus dorsi (LD) muscle of 30 pigs. Effects of polymorphisms on meat quality parameter such as pH, color and drip loss were also evaluated. Samples carrying CAST EU137105:g.76,872AA genotype showed higher autolyzed μ-calpain activity 24 and 72 h post-mortem, as well as lower drip loss values. Expression of CAST, CAPN1 and CAPN3 was assessed in LD muscles divergent for shear force. Higher CAST and CAPN3 expression was found in LD with high shear force (P<0.2), confirming a direct role for calpastatin but not for calpain 3 in meat tenderization. In conclusion, CAST gene affected post-mortem activation time of calpain and drip loss.     

The effect of pre-slaughter showering and post-slaughter rapid chilling on meat quality in intact pork sides

Thirty pairs of Landrace or Large White pigs were used to determine the effects of pre- and post-slaughter cooling treatments on pork quality and yield. One animal from each pair was showered in cold water and after slaughter one side from each carcass was rapidly chilled and the other side was conventionally chilled. Two experiments were carried out in winter: they examined different times of exposure to cooling treatments; a further experiment was carried out in summer time. Showering caused a reduction in the temperature of the deep loin at 40 min post mortem (P < 0·01). Rapid chilling caused a further reduction in carcass temperature and the rate of pH fall was lower (P < 0·05) in the rapidly chilled sides. There was a strong indication that showering in the winter time lowered drip loss in slices of Longissimus dorsi muscle (P = 0·077) whereas showering in the summer time was not effective. Shower water temperature may have been important in this regard. Showering did not lower drip loss in intact pork legs. Rapid chilling was not effective in lowering drip loss in either slices of Longissimus dorsi or intact pork legs. Rapid chilling at -20°C for 3 h without an air blast lowered evaporative chill losses in sides of pork by 27-29% (P < 0·1) compared to normal chilling. Reduced treatments gave reduced effects. Neither treatment had any significant effect on cooking loss or toughness in broiled slices of pork Longissimus dorsi muscle.     

Quality attributes and color characteristics in three-piece boneless hams

One hundred and fifty hams were selected on visual assessment of quality into normal (C) and two-tone (TT) groups. CIE LAB color and pH measurements were collected at the plant 48 h postmortem on the gluteus medius (GM), gluteus profundus (GP), and rectus femoris (RF), and again at 72 h on the semimembranosus (SM), biceps femoris (BF), semitendinosus (ST), and RF. Data were analyzed using GLM procedures of SAS, and correlations between color scores, pH, and drip loss were calculated. Plant and fabrication pH were lower (P < 0.01) in GM from TT hams compared with C. Muscles from TT hams had lower (P < 0.01) L* and a* values compared with C. The GM L* and GM pH values were correlated (P < 0.05) with L* values for all other muscles and drip loss in SM. These data show that GM color and pH are accurate predictors of pork quality attributes in the muscles of a three-piece boneless ham.     

Proteomic analysis of goat <Emphasis Type="Italic">Longissimus dorsi</Emphasis> muscles with different drip loss values related to meat quality traits

Longissimus dorsi muscles from 3 goat species were assigned to high and low drip loss groups. Physio-chemical properties, sarcomere length, and proteome profiles were investigated. The high drip loss group had lower pH, higher brightness, and higher shear force values, and shorter sarcomere lengths than the low drip loss group. 22 differential proteins were identified between high and low loss groups. α-Enolase, NADH dehydrogenase, pyruvate dehydrogenase E1, HSP27, superoxide dismutase, peroxiredoxin-2, myosin, and the myosin light chain were among these proteins, which were metabolic enzymes, stress response factors, and structural proteins that affected glycolysis, oxidation, and muscle contraction. Drip loss was probably produced via proteins involved in glycolysis, oxidation, and muscle contraction.     

EFFECT OF ELECTRICAL STIMULATION ON THE BOVINE CARCASS

Six grain-fed steer carcasses with weights ranging from 163 kg to 232 kg were randomly assigned to low voltage electrical stimulation (45 V., 1.5 A., pulsation cycle of 1.5 s for duration of 150 s) or no stimulation treatments. The longissimus dorsi (LD) and semitendinosus (ST) muscles were studied using high temperature (12 h at 32° to 39°C, then 36h at -2° to 0°C) and low temperature (36 h at -14° to -12°C) periods. Shear force, cooking loss, drip loss and taste panel data were taken. Shear force data indicated that differences (P < 0.05) existed between electrically stimulated and nonstimulated hot boned LD and ST muscle. Statistical differences (P < 0.05) in drip and cooking losses were detected. The duo-trio test indicated that panelists were able to detect a difference between electrically stimulated (ES) and nonstimulated muscle (P < 0.05). Preference tests indicated that panelists were also able to detect a difference between chill and delay chill. Ratings showed that a statistical difference was detected between ES and hot processed muscles.     

Carbon monoxide treatments to impart and retain muscle color in tilapia fillets

ABSTRACT:  Carbon monoxide (CO) has been used for improving the color of muscle foods. In the current study, we compared the postmortem treatment of tilapia fillets with 100% CO and euthanasia of live tilapia with CO for their ability to stabilize the color of white and red muscle of tilapia fillets. Both postmortem CO treatment and CO euthanasia were effective in increasing the redness ( a * value) and lightness ( L * value) of tilapia white and red muscle. Fillets obtained from CO-euthanized tilapia showed significantly higher a * and L * values during 1 mo of frozen storage at –20 °C and subsequent thawing and storage at 4 °C for 18 d. The amount of CO present in the red and white muscles decreased during the 18 d of storage at 4 °C. There was no significant difference in the pH, drip, or thaw loss of CO-treated tilapia fillets compared to the untreated fillets.     

不同部位猪肉肌纤维类型组成与品质特性比较研究

为比较不同部位猪肉肌纤维类型组成与品质特性的差异,选取9 头6 月龄杜长大三元杂交猪背最长肌（Longissimus dorsi）、半膜肌（Semimembranosus）和半腱肌（Semitendinosus）3 个部位猪肉作为研究对象,通过烟酰胺腺嘌呤二核苷酸四唑氧化还原酶（nicotinamide adenine dinucleotide-tetrazolium reductase,NADH-TR）染色法研究不同部位猪肉的肌纤维类型组成,并分析肌纤维类型数量比例、平均直径、横截面积、密度等肌纤维特性;测定不同部位猪肉的品质特性（pH值、色泽、蒸煮损失率、剪切力以及质构特性）。结果表明,背最长肌和半膜肌中主要为ⅡB型肌纤维（P＜0.05）,数量比例分别为82.03%和53.22%,半腱肌则主要由Ⅰ型（45.44%）和ⅡB型（39.01%）肌纤维组成。半膜肌中各类型肌纤维的平均直径和横截面积较大,总肌纤维密度最小（P＜0.05）,为42.15 根/mm2。背最长肌的亮度值和蒸煮损失率最高（P＜0.05）,pH值和红度值最低（P＜0.05）;半膜肌的剪切力最高（P＜0.05）;半腱肌的pH值和红度值最高（P＜0.05）,亮度值、剪切力和蒸煮损失率最低（P＜0.05）。     

Investigation on interferon alpha-inducible protein 6 (IFI6) gene as a candidate for meat and carcass quality in pig

The aim of this research was to screen for polymorphism and to perform an association study of IFI6 with meat and carcass quality traits. A SNP (g.370A>G) was detected which was associated (P<0.05) with meat colour, pH 24h post mortem (p.m.) in ham, conductivity 45 min p.m. in loin and conductivity 24 h p.m. in ham, drip loss and carcass length in Duroc x Pietrain and with meat colour, muscle area and ham percentage in the Pietrain population. Highest expression of IFI6 mRNA was detected in skeletal muscle (longissimus dorsi) by qRT-PCR comparing different tissues. Both qRT-PCR and western blot revealed that the IFI6 gene and protein expressions were significantly (P<0.05) higher in skeletal muscle with low drip loss compared to that of high drip loss. IFI6 protein was localized in the myocytes membrane. Results suggested that IFI6 might play roles in meat and carcass quality and is a potential positional, physiological and functional candidate gene for improving meat quality traits in pigs.     

Effects of postmortem temperature and time on the water-holding capacity of hot-boned turkey breast and thigh muscle

Turkey breast and thigh muscles were excised immediately after slaughter and held from 0.25 to 4 h postmortem at 0, 12 or 30 °C to determine postmortem time and temperature effect on muscle pH, drip loss, sarcomere length, homogenate supernatant weight, salt-soluble protein and cooking yields. Higher temperature and longer storage time induced greater drip losses in breast. Longer storage time induced greater drip losses but the least drip loss occurred at 12 °C in thigh muscle. High temperature increased the supernatant weight in breast but decreased that in thigh. Storage time increased supernatant weight and supernatant salt soluble protein levels in both muscles. Homogenate cooking yields of breast containing water, salt and phosphate (HWSP) were higher for 0 and 12 °C compared with 30 °C, and increased with storage. The low postmortem temperature (0 °C) decreased homogenate cooking yields in thigh. These findings indicate that lower postmortem temperatures (0 and 12 °C) and shorter storage time (24 h) produced the greatest water-holding capacity in turkey breast muscle, whereas high and low postmortem temperatures (30 and 0 °C) and longer storage (168 h) produced the least water-holding capacity in raw turkey thigh muscle.     

The effect of high post-mortem temperature on the development of pale, soft and exudative pork: Interaction with ultimate pH

The effects of post-mortem temperature and ultimate pH (pH(u), 24 h post mortem) on the development of the pale, soft and exudative (PSE) characteristics in pig longissimus dorsi muscle were studied. Ten out of the 13 pigs used received pre-slaughter injections of adrenaline in order to deplete muscle glycogen stores. The two muscles from each pig were held at 12 or 35°C during rigor mortis development. Results from covariance analysis, using pH(u) as covariate, showed that a high temperature (35°C) resulted in a dramatic increase in internal light scattering (FOP) 24 h post mortem and a significant decrease in water- and salt-soluble proteins. Cooking loss, sarcomere length and drip loss did not vary significantly with rigor temperature. Interaction between temperature and pH(u) was estimated by assessing the relationship between pH(u) and the difference between the two rigor temperatures for selected traits. The best predictive model was a segmented quadratic model with a plateau which gave significant results for FOP, drip loss, water- and salt-soluble proteins. The effect of temperature decreased curvilinearly when pH increased until a constant value above which no noticeable difference was recorded (drip loss, water- and salt-soluble proteins) or a constant difference was reached (FOP). The pH values corresponding to the convergence points differed from one trait to another. They ranged from 5·72 to 6·22. These results illustrate the importance of muscle glycogen content at slaughter and subsequent pH(u) with regard to the development of temperature-induced PSE meat.     

宰后猪肉pH值、骨架蛋白表达水平和持水性之间的关系

以20头猪的背最长肌为材料,分别于宰后45 min和3、9、12、24 h测定猪背最长肌的pH值和整联蛋白、黏着斑蛋白、踝蛋白表达水平,并测定汁液流失率,探讨它们之间的关系.结果显示:高pH组(pH45 min≥6.00,n=6)的汁液流失率和踝蛋白表达水平低于低pH组(pH45 min≤5.78,n=14),整联蛋白...     

Using electricity as a tool in quality studies of Atlantic salmon

In order to reveal what role anaerobe muscle activity has on the fillet quality in Atlantic salmon (Salmo salar), 18 rested fish were killed on site and immediately filleted. One fillet was used as control group while the other was electrically exercised using 10 V, 5 Hz pDC for 3 min. Fillet weight and muscle pH was measured before the fillets were wrapped in aluminum foil and stored on ice. After 7 days muscle pH, color, and weight was measured. Texture profile analysis (TPA) was estimated using a 20 mm cylindrical probe compressing either at 40, 60 or 80% into the fillet and the shear force was estimated by slicing standardized muscles samples with a blade. Results show that electrical stimulation forces the muscle to contract and the muscle pH to drop by 0.5 units, leading to higher drip loss and loss of color. Comparing the fillets in pairs (paired t test) strengthens evidence on drip loss and color loss, but revealed also softer texture. Optimum compression rate for detecting differences in salmon muscle is at 60% compression. We conclude that electrical stimulation is a powerful tool for simulating anaerobe muscle activity enabling comparative studies within the same individual, hence isolating the variation amongst individuals and the location of sampling. Furthermore electrical stimulation reduces the need for live animal experimentation in quality studies.     

WATER-HOLDING AND COLOR CHARACTERISTICS OF BEEF FROM ELECTRICALLY STIMULATED CARCASSES

Electrical stimulation (ES) was applied to the right sides of 15 beef carcasses and the corresponding left sides were used as nonstimulated (NS) controls. Data collected included: postexsanguination pH (0.5, 3, 6, 24 h), L, a, and b color values, drip loss, and expressible moisture. Muscles from ES carcasses tended to have more accelerated postmortem pH declines than the corresponding muscles from NS carcasses. M. triceps brachii had a lower pH at 0.5 h (P < 0.05) , M. longissimus thoracis had a lower pH at 0.5 h (P = 0.055) and 3 h (P < 0.05), and M. semimembranosus had a lower pH at 0.5 and 3 h (P < 0.05), respectively. Hunter L, a, and b values did not differ within ES and NS treated muscles. Additionally, ES did not influence color values of the M. semimembranosus. ES did not affect drip loss or expressible moisture in beef muscles.     

长途运输应激对西门塔尔牛不同部位肉品质指标的影响

为研究长途运输所产生应激对西门塔尔牛不同部位肉品质指标的影响,选取12 头西门塔尔公牛,随机分为运输组（运输距离＞600 km）和对照组（未运输组）,对其冷却排酸成熟72 h后背最长肌、半腱肌和冈上肌的pH值、色差值、持水力和剪切力进行测定。结果表明：与对照组相比,长途运输产生的应激反应导致西门塔尔牛肌肉宰后pH72 h值显著升高（P＜0.05）,冈上肌极显著升高（P＜0.01）;滴水损失率、蒸煮损失率和压力失水率显著增大（P＜0.05或P＜0.01）,但半腱肌的滴水损失率、背最长肌的蒸煮损失率和压力失水率在长途运输前后无显著差异（P＞0.05）;运输后3 个部位肉的剪切力增大,亮度值（L*）极显著降低（P＜0.01）,红度值（a*）和黄度值（b*）分别有不同程度的变化,b*仅在背最长肌中显著增大;长途运输后,除a*和b*之外,冈上肌的其他质量指标均变化显著（P＜0.05或P＜0.01）。运输应激对牛肉品质具有显著影响,会降低其品质,对不同部位肉的影响不同,其中冈上肌的变化程度最大。     

The intracellular distribution of small heat shock proteins in post-mortem beef is determined by ultimate pH

This study analysed Longissimus dorsi muscles from 39 Angus or Angus×Limousin bulls to determine the small heat shock protein (sHSP) dynamics in beef aged at 15°C. Using quantitative ELISA we determined that alpha β-crystallin and HSP20 were present at higher levels in muscles from Angus bulls. sHSP levels peaked at 0.5 and 3h post-mortem for HSP20 and alpha β-crystallin respectively. Intermediate pH (pH 5.7-6.3) beef had the highest level of alpha β-crystallin expression at 3-6h post-mortem. Low pH (<5.7) meat had no detected soluble alpha β-crystallin and had diminished HSP27 at 22h post-mortem. The transition of sHSP between a soluble to an insoluble phase was demonstrated by pH titration of a sarcoplasmic fraction. The effect of ultimate pH upon sHSP distribution in post-mortem muscle may influence final meat quality characteristics.     

Genetic parameters of carcass and meat quality traits of double muscled Piemontese cattle

Genetic parameters of meat quality (MQ) were estimated on Longissimus thoracis muscle of 1208 Piemontese young bulls, progeny of 109 AI sires. Carcass weight (CW), conformation (EUS) and pH (pH24h) were recorded at 24h and lightness (L*), redness (a*), yellowness (b*), pH (pH8d), drip loss (DL), cooking loss (CL) and shear force (SF) were assessed. The heritability (h(2)) of pH24h was very low (0.06), but h2 of pH8d was markedly higher (0.42). Heritability was 0.32, 0.33, and, 0.14, for L*, a* and b*, respectively, whereas was 0.24, 0.07 and 0.14, for DL, CL, and SF, respectively. The two pH measures showed opposite genetic relationships with color measures. Genetic correlations of DL and CL were positive with L* and b* and negative with a*. Genetic correlations between carcass traits and MQ suggest that animals with superior growth potential tend to exhibit reduced EUS scores and pale meat with lower tenderness and water holding capacity. Conversely, improvement of EUS score through selection would lead to light, bright, and tender meat with enhanced water holding capacity.     

The effects of high pressure processing on pork quality, palatability, and further processed products

The objective was to evaluate high pressure processing (HPP) on postmortem metabolism and pork quality. Six pigs were randomly selected immediately after slaughter. After splitting, one side was randomly designated for HPP of 215 MPa for 15 s with water temperature at 33 °C and the other side (non-pressure treated) served as the control. Chilled sides were fabricated into loins, boneless picnic, boneless Boston butt, and ham. Samples were cut from the loin, inside portion of the ham and cushion (M. triceps brachii). Pork quality, lipid oxidation, connective tissue solubility, protein functionality, sensory analysis, and processed characteristics of restructured hams were evaluated. HPP partially inhibits postmortem metabolism, indicated by lower muscle lactate levels and higher ultimate pH values. Cook and drip loss were both reduced in HPP treated muscles compared to controls. HPP treated sides were more tender than controls. Collagen content was not different between HPP and control groups.