Proximate composition, selected minerals, cholesterol content and lipid oxidation of mechanically and hand-deboned chickens from the Jordanian market

Samples of chicken were prepared using four treatments: (1) manual deboning of whole chickens; (2) manual deboning of skinned chickens; (3) mechanical deboning of whole chickens; (4) mechanical deboning of skinned chickens. The meat was packaged in polyethylene bags, frozen and stored at -18?°C. Treatments 2 and 4 resulted in the lowest fat content. Some minerals, e.g. Fe, Na, Al, K, and Mg did not vary among the four products, while others, e.g. Ca, Zn and Mn were significantly higher in Treatments 3 and 4 compared with Treatments 1 and 2. Cholesterol content was directly proportional to fat content; Treatment 3 gave the highest cholesterol content, while the lowest cholesterol level resulted from Treatment 2. Thiobarbituric acid (TBA) determinations to evaluate oxidative rancidity of fat in the samples showed that Treatments 1 and 3 gave significantly higher values than Treatments 2 and 4.     

Effect of salt and phosphate on the quality of Buffalo and Goat meats

A study was conducted on the effect on certain quality parameters of adding sodium chloride (2·5%) and tetrasodium pyrophosphate (1%) to hot minced buffalo and goat meats. The effects on buffalo meat were observed in chilled and frozen conditions, those on goat meat in hot and chilled conditions. These treatments significantly increased pH, water-holding capacity (WHC) and emulsifying capacity (EC) and decreased cooking loss in both types of meat. Chilled and frozen conditions did not affect buffalo meat quality but salt additions to hot minced goat meat were superior to such additions to chilled minced meat in respect of EC and the extraction of salt-soluble proteins. Buffalo meat had poorer WHC and EC than goat meat and salt additions had a greater effect in improving EC. With goat meat, the treatment resulted in an increased WHC with a greater increase in pH. Significant correlations were observed among quality parameters.     

Use of electrical conductivity to predict water-holding capacity in post-rigor pork

This study was designed to re-examine the interrelationships among ultimate pH (pH_u), electrical conductivity (EC) and water-holding capacity (WHC), and to test if EC, using one of two EC instruments, and pH_u can be used to predict WHC. The % drip (PD) was used as measure of WHC. Forty-seven pork loins were classified either as PSE (pale, soft, exudative), RSE (reddish-pink, soft, exudative), RFN (reddish-pink, firm, non-exudative) or DFD (dark, firm, dry), based on L* values, PD and pH_u. The measurement of EC, conducted using the instrument developed at the University of Wisconsin-Madison (UW-EC) was highly correlated to PD at 24 h post mortem (CD=66%), but the pH (NWK) measure of EC was not as highly related to WHC as UW-EC. The predictive value of pH_u and EC for WHC were similar. When 47 samples were divided into three different groups, such as low (< 2% drip), medium (2–6% drip) and high (> 6% drip) drip loss, UW-EC alone grouped 80% of the samples correctly. Thus, EC seemed to be an accurate predictor of WHC in pork muscle when measured at 24 h post mortem. It is conceivable that EC can be used independently, or with even better success in combination with pH_u, to classify WHC of pork carcasses.     

Effect of electrical stimulation on quality of tenderstretched chevon sides

Thirty male Black Bengal goats 5-8 years of age, slaughtered at the Kolkata slaughter house, India, by the traditional 'halal' method, were used to assess the effect of electrical stimulation on tenderstretched sides of chevon carcasses. Five groups (T1, T2, T3, T4 and T5) were treated with variable voltages of 35, 110, 330, 550, 1100 with fixed 50Hz and 10pulses/s for a duration of 3min. Different quality parameters, such as, fibre diameter, sarcomere length, water holding capacity (WHC), pH, microbial content and taste panel score were studied at 24 and 48h post-stimulation. pH, WHC and fibre diameter decreased whereas sarcomere length showed an increasing trend in electrically stimulated meat, which was also microbiologically more stable. The non-stimulated control meat was tougher than the electrically stimulated chevon as evident through taste panel scoring. Treatment 3 (T3), i.e. 330V, 50Hz and 10pulses/s, showed superiority over the other four treatments in the majority of the important meat quality parameters.     

Influence of the season on the relationships between NMR transverse relaxation data and water‐holding capacity of turkey breast meat

In the last few years the poultry industry has seen a significant deterioration in meat quality properties during the summer season. The objective of this study was to evaluate the seasonal effect (summer and winter) on turkey meat quality assessed by both conventional and low‐resolution nuclear magnetic resonance (LR‐NMR) analysis. Eighty‐eight breast muscle samples (35 winter and 53 summer) from BUT‐Big 6 turkeys belonging to 16 different flocks, were randomly collected from a commercial processing plant. The samples were analysed for transverse relaxation times (T₂) by LR‐NMR and for initial pH (15 min post mortem), ultimate pH (24 h post mortem) and pH after cooking, temperature at 15 min post mortem, water‐holding capacity (WHC, drip loss, filter paper press wetness and cooking loss) at 24 h post mortem, colour of raw and cooked meat and chemical composition (moisture, lipids and proteins). The results indicate that, during the summer season, turkey breast meat undergoes a relevant WHC decrease. Cluster analysis of the raw LR‐NMR data evidenced the presence of two groups corresponding to samples harvested in each different season. Correlations between the LR‐NMR signal and the conventional parameters measuring WHC were obtained by a recently proposed type of principal component regression (PCR) termed relative standard deviation PCR. Copyright © 2004 Society of Chemical Industry     

Metabolite Profile Differences Among Different Storage Time in Beef Preserved at Low Temperature

Storage temperature influences meat color stability and quality. This study was performed to quality change‐associated metabolites profiles using a nontargeted liquid chromatography‐mass spectrometry (LC‐MS/MS)‐based method. Beef longissimus dorsi samples were purchased immediately after slaughter, and then stored at room temperature, 4 °C and 0 °C. Water holding capacity (WHC), moisture content and pH value of the muscle samples were detected. Muscle samples and quality control samples were then prepared for nontargeted LC‐MS/MS system, followed by identification of distinct metabolites. Pearson correlation coefficients between metabolites and quality indexes were calculated. Storage reduced pH values of beef, and room temperature and 4 °C displayed the lowest pH value. Moisture content and WHC in beef muscles, especially WHC declined obviously during the first 24 hr. The significantly altered metabolites profiles in meat samples at 0, 3.5, and 7 days during 4 °C storage were identified using LC‐MS/MS. Most metabolites showed linear changes during storage (0 to 7 days). Using Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, we found 1(α)‐naphthol, urocanic acid, tyramine, guanine, histamine, picolinic acid, 4‐hydroxybenzaldehyde, and hypoxanthine were increased, and 2‐(S‐glutathionyl)acetyl glutathione and glutathione were decreased in beef during 4 °C storage. Correlation analysis showed there were significantly correlations between metabolites and meat quality indexes (WHC, moisture content, and pH). In summary, 1(α)‐naphthol, urocanic acid, tyramine, guanine, histamine, picolinic acid, 4‐hydroxybenzaldehyde, and hypoxanthine, proved to be harmful to human body, accumulated gradually, especially after 3.5 days during storage at 4 °C. While the contents of beneficial substances, including 2‐(S‐glutathionyl)acetyl glutathione and glutathione, were decreased, which provided reference for the nutrition guidance of using beef meat.     

猪肉色泽和保水性的相关性研究

以猪瘦肉为原料展开猪肉色泽和保水性之间的相关性研究,一部分以来源于同一猪胴体的肉样为原料,另一部分采用从市场上随机抽样的样品为原料,研究肉样的保水性和肉色之间的相关性。结果表明：对于来源于同一个体的肉样而言,保水性与色泽无关;而来源于不同个体的肉样,加压系水力(WHC)与亮度(L 值)呈负相关,蒸煮损失与L 值和黄度(b 值)呈正相关,即L 越大,b 越大,保水性越差;在实验测定的范围内,pH 值与蒸煮损失呈负相关,与加压系水力呈正相关,表明pH 值越高的肉样,保水性越好;来源于同一个体的肉样,随着宰后时间的延长,其保水性有增强的趋势,表现为蒸煮损失与时间呈负相关,加压系水力与时间呈正相关。     

Effect of chilling applied to suckling lamb carcasses on hygienic, physicochemical and sensory meat quality

The effect of post mortem temperature treatment on suckling lamb carcass and meat quality was study. Conventional (2°C for 24h), ultra-rapid (-20°C for 3.5h, 2°C until 24h) and slow chillings (12°C for 7h, 2°C until 24h) were compared. Total viable counts (TVC), weight losses, and pH and temperature falls were recorded on carcasses. Meat colour, water holding capacity (WHC), Warner-Bratzler shear force, sarcomere length and sensory analysis were evaluated in M. longissimus. Ultra-rapid treatment reduced TVC and weight losses. The pH decline was faster in slow chilled carcasses than in faster chilled carcasses. No significant differences were found for colour and WHC. Slow treatment carcasses showed significantly lower shear force and higher sarcomere length. In the sensory analysis, tasters also rated the early post mortem slow-treated meat as more tender, less fibrous and chewy. Therefore, delay chilling in suckling lamb carcasses made it possible to obtain meat with better organoleptic characteristics, without affecting weight loss or hygienic quality.     

Hot-boning, Tumbling, Salt and Chopping Temperature Effects on Cooking Yield and Acceptability of Emulsion-type Pork Sausage

Hot-boned or chilled pork with addition of 2% or 3% salt was used to prepare emulsion-type pork sausage. Different tumbling periods and a variety of chopping temperatures were evaluated. Emulsifying capacity (EC), water-holding capacity (WHC), pH, total plate count (TPC) and organoleptic properties were determined. Hot boned pork with 3% added salt had higher EC, pH, WHC, cooking yield and lower TPC than chilled meat samples with 2% added salt. As chopping temperature increased, WHC decreased and TPC increased. However, an intermediate chopping temperature of 12.8°C produced superior yield.     

Effects of Freezing on Physical Properties and Sensory Characteristics of Meat from Fryer and Senior Rabbits

The effects of age (fryer vs senior) and freezing (fresh vs frozen) on the physical properties and sensory characteristics of loin meat from domestic rabbits were examined using a 2 × 2 factorial experiment. Freezing resulted in a decline in moisture and an increase in protein. Total cooking loss tended to be greater from carcasses which had been frozen. Shear values of fresh meat from fryer carcasses were significantly less than those from senior carcasses. Water-holding capacities exhibited no differences. Taste panelists judged meat from fresh fryer carcasses more tender and juicier than that from senior rabbits. Flavor differences were not detected.     

The effect of various types of poultry pre- and post-rigor meats on emulsification capacity, water-holding capacity and cooking loss

In this study, the relationship between various kinds of poultry meat (quail, partridge, chicken and turkey) on pH, emulsification capacity, water-holding capacity and cooking loss was investigated. The effect of rigor state on pH, emulsification capacity, water-holding capacity and cooking loss was also determined. To investigate these parameters, immediately after slaughter and deboning, meat parts were submitted to both pre- and post-rigor analyses. The results indicated that the emulsification capacity of quail and chicken meat was higher than the values for partridge and turkey meat. Quail meat showed the highest water-holding capacity value in the post-rigor stage. The lowest cooking loss value was found in partridge meat, in both pre- and post-rigor stages. The state of rigor had a significant (P<0.05; P0.01) effect on pH and cooking loss values, respectively.     

Effects of extrusion screw speed,feed moisture content,and barrel temperature on the physical,techno-functional,and microstructural quality of texturized lentil protein

Utilizing lentil protein as a novel ingredient for producing texturized vegetable proteins (TVPs) can provide new opportunities for the production of next-generation hybrid meat products. TVPs from lentil protein isolate were manufactured using low-moisture extrusion cooking at different combinations of screw speed (SS), feed moisture content (MC), and barrel temperature (BT) profile. In total, seven different combinations of processing treatments were tested, and the resulting TVPs were characterized for their physical (rehydration ratio, texture profile analysis, color, and bulk density), techno-functional (oil and water holding capacities), and microstructural properties. The processing conditions of higher SS and lower MC resulted in increased values of several textural profile attributes (springiness, cohesiveness, and resilience), increased water holding capacity (WHC), and decreased bulk density. Compared to raw lentil protein, TVPs showed enhanced oil holding capacity, though WHC either decreased or remained constant. The extrusion response parameters (die pressure, torque, and specific mechanical energy) showed positive correlations with several physical properties (texture, WHC, and total color change), revealing their potential for serving as important TVP quality indicators. TVPs produced at SS, MC, and BT of 450 rpm, 30%, and 140°C, respectively, showed relatively better overall physical and techno-functional quality and can be used as meat extenders in hybrid meat patties. Overall, this research evidenced the viability of lentil protein as a potential ingredient for producing low-moisture TVPs.     

Effect of freezing, thawing and frozen storage on physico-chemical and sensory characteristics of buffalo meat

A study was conducted on some physico-chemical and sensory characteristics of buffalo meat frozen by plate and blast freezing and stored at −15 ± 3°C for a period of 3 months. A marginal increase in pH values and drip losses were observed during the storage period. Drip losses were less in blast frozen samples. WHC, cooking losses thermal shrinkage and WB Shear values indicated inconsistent results, during storage. Similar observations were recorded with regard to tyrosine and TBA values. No significant differences in the physico-chemical characteristics were observed between meat cuts and minced meat. Plate frozen meat samples scored higher for texture, juiciness and aroma. Both the plate and blast frozen meat samples, however, were similar in overall quality according to taste panel results.     

Meat quality in suckling lambs: effect of pre-slaughter handling

Thirty-three suckling lambs of the Manchega breed were used to compare the effects of pre-slaughter handling (PSH) on initial meat quality and at 7 days post-mortem. Lambs were distributed into three groups: electrically stunned (ESL; n=15), stunned using CO(2) (GSL; n=10) and slaughtered without previous stunning (USL; n=8). Meat quality was evaluated by examining pH, colour (L*, a*, b* values), water holding capacity (WHC), cooking loss (CL), shear force (SF) and drip loss (DL). At 24 h post-mortem, the highest pH corresponded to the USL group (P<0.05) whereas the lowest pH decline (pH(0)-pH(24)) corresponded to the GSL group (P<0.05). Differences in pH among groups disappeared after 7 days post-mortem. In general, PSH did not affect values of WHC, CL and colour parameters. After 7 days post-mortem, there were significant differences between groups in DL, this being lowest (P<0.05) in stunned animals. GSL resulted in more tender meat (lower SF value) than ESL and USL (P<0.05). Moreover, there was no blood splash in any of the carcasses of the GSL group.     

Effects of dietary humate supplementation to broilers on performance,slaughter, carcass and meat colour

BACKGROUND: This experiment was designed to examine the effect of dietary humate supplementation primarily on pH and colour parameters of carcasses, breast fillets and drumsticks and, secondarily on performance and carcass characteristics in broilers. RESULTS: A total of 240 male broiler chicks (Ross‐308) were randomly allocated to four dietary treatments varying in supplemental humate level (0, 0.1, 0.2 and 0.3% for H₀, H₁, H₂ and H₃). Dietary humate supplementation did not affect performance traits and slaughter, hot carcass weights and yields. Carcass‐related variables (pH, L*, a*, b*, H* and C*) were responsive to the dietary treatments. The L*, a*, b*, and C* values for drumstick muscles were higher than those for breast muscles. Except for the L* value, meat colour parameters changed due to packaging. The a* value was higher and b* value was lower for vacuum packaged breast and drumsticks than for those aerobic packaged. Storage period affected colour parameters; while L*, b*, H* and C* values were higher for drumstick skin than for drumstick meat; the a* value was greater in drumstick meat than in skin. CONCLUSION: pH and colour parameters of carcasses, breast fillets and drumsticks of broilers were improved by dietary humate supplementation. However, responses of broiler performance and slaughter and carcass characteristics were minimal. Copyright © 2008 Society of Chemical Industry     

Visible contamination on animals and carcasses and the microbiological condition of meat

It is generally assumed that preventing visible contamination of or removing visible contamination from carcasses will enhance the microbiological safety of meat. Visible contamination of carcasses can be reduced by washing or otherwise cleaning animals before slaughter, by dehairing hides before carcasses are skinned or dressed with the skin on, or by performing skinning and eviscerating operations in manners that avoid the transfer of filth from the hide to the meat or the spillage of gut contents. Visible contamination can be removed by washing, trimming, or vacuuming carcasses. The available data appear to indicate that, of the various actions that can be taken to obtain carcasses that are free of visible contamination, only minimizing the visible contamination of meat during skinning and eviscerating operations may also ensure a degree of control over the microbiological contamination of meat. It might be preferable for visible contamination to be controlled largely by superior skinning and eviscerating practices rather than by animal or carcass cleaning treatments, which may not prevent the depositing of bacteria on or the removal of substantial numbers of bacteria from carcasses.     

Combined effect of electrical stimulation, aging time and marination on quality of chicken breast fillet processed under commercial conditions

BACKGROUND: Electrical stimulation (ES) in poultry processing is reported in the literature with varying degrees of effectiveness. Furthermore, the combined effects of ES and polyphosphate marination are not completely known. The objective of this study was to evaluate the combined effect of ES, aging time prior to deboning and phosphate marination on meat quality of broiler breast fillets. RESULTS: The implementation of ES accelerated pH decline in fillets at any aging time studied regardless of marination treatment, but no differences (P > 0.05) were found in pH of fillets deboned without aging. Warner–Bratzler (WB) shear values of ES fillets significantly decreased (P < 0.05) at 2 h of aging whereas WB of non‐ES fillets decreased at 6 h of aging in breast meat, with or without marination. In non‐marinated fillets the ES treatment reduced (P < 0.05) cooking loss in meat aged 0, 2 and 4 h. In marinated fillets the ES treatment decreased cooking loss at 2, 4, 6 and 8 h of aging. CONCLUSION: ES in carcasses aged 2 or 4 h improves tenderness and reduces cooking loss. Marination improves tenderness in both stimulated and non‐stimulated fillets, at all aging times. Copyright © 2012 Society of Chemical Industry     

Microbiological quality of rabbit meat

World rabbit meat production is estimated to be over 1 million tons, and Spain is the third largest producer. Although rabbit meat is marketed and consumed worldwide, information on microbiological quality is very scarce. Here, we report indicator organisms, spoilage flora, sensory quality, and some physicochemical traits of 24 h postmortem chilled rabbit carcasses and prepackaged rabbit meat stored chilled in air for 0 to 3 days at the retail level. The mean total bacterial count (4.01 +/- 0.48 log CFU/g) for carcasses dressed at a small abattoir by a manual process was significantly lower (P < 0.05) than that (4.96 +/- 0.90 log CFU/g) for carcasses dressed at a large abattoir in automated slaughter lines. Both groups of carcasses had mean pH values of 5.98. The dominant contaminants on carcasses from the small abattoir were Pseudomonas, lactic acid bacteria, and yeasts. These microorganisms and Brochothrix thermosphacta were dominant on carcasses from the large abattoir. On prepacked hind legs (pH 6.26 +/- 0.18) stored at -1 to +1 degree C (supermarket 1), mean aerobic mesophilic count was 5.87 +/- 1.03 log CFU/g, and the major microbial groups were Pseudomonas, yeasts, lactic acid bacteria, and B. thermosphacta. On prepacked whole carcasses (pH 6.37 +/- 0.18) displayed at -1 to +5 degrees C (supermarket 2), mean aerobic mesophilic count was 6.60 +/- 1.18 and the same microbial groups were dominant. Relative Escherichia coli incidence was supermarket 2 > large abattoir > supermarket 1 > small abattoir. Overall, low numbers of coliforms, Enterobacteriaceae, psychrotrophic clostridia, coagulase-positive staphylococci, and molds were found. Sensory scores, pH values, and L-lactic acid content differentiated fresh carcasses from retail samples. Data obtained suggest that the microflora of chilled rabbit meat are different from those found on the meat of other animals.     

Phosphates and antioxidants as cryoprotectants in meat batters

The gelation and rheological properties of minced beef frozen and stored at -18°C for 6 months without additives, with salt (1·5% NaCl), tripolyphosphate (TPP 0·5%), sodium acid pyrophosphate (SAPP 0·5%) and an antioxidant mix (BHA + BHT, 200 ppm) were studied. The relationships between shear rate and shear stress for the different treatments were nonlinear and resembled the Bingham pseudoplastic behaviour. Continuous evaluation of the modulus of rigidity (G) during cooking (0·5°C/min) revealed higher G values for the unfrozen phosphate treatments. Salt addition resulted in significantly lower G values of the stored meat compared to the control. Antioxidant addition retarded some of these effects. Among the phosphates, TPP was the best in maintaining the same G values as the control. Water-holding capacity (after salt addition) was increased after phosphate addition in the unfrozen meat and did not change after storage. The control, NaCl and antioxidant treatments showed an increase in WHC during storage.     

A note on the relationships between measures of water holding capacity in the M. longissimus dorsi and total drip loss from butchered pig carcasses during storage

Twenty pig carcasses were selected to represent a range of meat quality. The water holding capacity (WHC) of the M. longissimus dorsi (LD) was estimated using several methods and the usefulness of these measures examined to predict the overall loss in weight from the butchered carcasses when jointed and displayed in a manner corresponding to a retail situation. There was a linear relationship between the logarithms of percentage loss in weight of the butchered carcass and days of display time. The total weight loss from the butchered carcasses after 5 days ranged from 2·2 to 6·4% and the best relationship with this weight loss was for WHC assessed by loss of exudate from slices of LD suspended in netting bags for 72 h at 1°C (r = 0·88, P < 0·001). Measures of WHC based on high or low speed centrifugation, or a filter paper press method, gave slightly poorer correlations. However, all WHC methods except low speed centrifugations gave correlations which were better than those with pH measured at 45 min post mortem, or reflectance or Fibre Optic Probe Values at 24 h post mortem.