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1.
The aim of this study was to investigate the effect of pre-slaughter fasting time, sex and feeding regime on water-holding capacity (WHC), colour and sensory properties and their relationship with pH in M. longissimusdorsi (LD) in pigs. 270 pigs of the commercial Norwegian crossbreed Noroc (Norwegian Landrace × Yorkshire sow and Norwegian Landrace × Duroc boar) were used involving two sexes (gilts and castrates), two feeding regimes (restricted and ad libitum) and four fasting treatments: (F4) 4 h fasting (control), (F175) 17.5 h fasting on the farm, (FO175) 17.5 h fasting overnight at the abattoir, and (FO265) 26.5 h fasting overnight at the abattoir. Additionally, the pigs experienced two abattoir lairage times as fasting treatments F4 and F175 had a lairage time of 1.5 h, while fasting treatments FO175 and FO265 had a lairage time of 23.0 h. A short fasting time of 4 h led to a delayed decline in pH post-mortem and a lower ultimate pH (pHu) in the LD compared with a fasting time of 26.5 h which resulted in a rapid pH decline early post-mortem and a high pHu. Prolonged fasting reduced drip loss, resulted in a darker colour and tended to improve tenderness of the LD. Castrates showed lower drip loss, higher lightness and improved tenderness and juiciness compared with gilts, while ad libitum feeding improved tenderness compared to restricted feeding. There are obvious negative relationships between pHu and drip loss, lightness and tenderness of LD.  相似文献   

2.
The experiment examined the influence on pork quality of the electrical stimulation of carcasses from pigs subjected to different ante-mortem handling treatments. The carcasses were subjected to a slow chilling regimen to reflect less than ideal commercial practice. A total of 288 pigs (mean live weight 89 kg) of both sexes and a range of genotypes were used. They came from the Meat and Livestock Commission 's Pig Development Unit at Stotfold and were processed in 12 equal batches. Prior to slaughter they were transported for 2 h (80 km) at a stocking density of 0.5 m(2)/100 kg live weight. Preslaughter handling included being mixed or not with unfamiliar animals and being given a 3 h rest in lairage or not. One group received handling to simulate that in stunning races immediately before slaughter. There were no material interactions between the effects of ante- and post-mortem handling. Pigs rested 3 h in lairage had lower plasma cortisol levels irrespective of whether mixed with unfamiliar animals. Plasma lactate concentrations increased with greater ante-mortem stress. Pigs subjected to the simulated stunning race treatment had elevated carcass temperature. Greater ante-mortem stress progressively elevated pHu in the muscles and tended to reduce eating quality. Electrical stimulation followed by slow chilling raised initial muscle temperature, reduced pH(45) and pHu, and produced meat that was paler, had higher hue and saturation values and lost more drip during storage. Neither instrumentally-determined texture nor taste panel texture was affected, but electrical stimulation decreased juiciness and increased pork flavour. Overall eating quality was not affected by stimulation.  相似文献   

3.
The objective was to study prediction of pork quality by near infrared spectroscopy (NIRS) technology in the laboratory. A total of 131 commercial pork loin samples were measured with NIRS. Predictive equations were developed for drip loss %, colour L*, a*, b* and pH ultimate (pHu). Equations with R(2)>0.70 and residual prediction deviation (RPD)≥1.9 were considered as applicable to predict pork quality. For drip loss% the prediction equation was developed (R(2) 0.73, RPD 1.9) and 76% of those grouped superior and inferior samples were predicted within the groups. For colour L*, test-set samples were predicted with R(2) 0.75, RPD 2.0, colour a* R(2) 0.51, RPD 1.4, colour b* R(2) 0.55, RPD 1.5 and pHu R(2) 0.36, RPD 1.3. It is concluded that NIRS prediction equations could be developed to predict drip loss% and L*, of pork samples. NIRS equations for colour a*, b* and pHu were not applicable for the prediction of pork quality on commercially slaughtered pigs.  相似文献   

4.
This study investigates the effect of different transport times on meat quality and the correlation between meat quality and Hsp expression in M. longissimus dorsi (LD) of pigs. After transportation for 1 h, 2 h or 4 h, respectively, blood plasma creatine kinase (CK) and lactate dehydrogenase (LDH) increased. The LD meat from 1 h and 2 h transported pigs had lower initial and ultimate pH values (pHi and pHu, respectively), higher drip loss and L values compared to controls, indicating a higher likelihood of pale, soft and exudative (PSE) meat. Meat quality was lower after 2 h compared to 1 h or 4 h of transport. All four Hsps tested (alpha-B-crystalline, Hsp27, Hsp70 and Hsp90) by ELISA in the LD tissue of pigs tended to decrease after transportation. One possible mechanism resulting in poor meat quality in the LD after transport seems to be a decline in Hsp expression.  相似文献   

5.
Effect of processing plant on pork quality   总被引:1,自引:0,他引:1  
The impact of processing plant on pork quality was studied by assessing pork quality in three commercial plants (A, B, C). Plants differed in the layout of the races, stunning systems (A and B: electrical, C: CO(2) stunning) and chilling systems (A: rapid chilling, B and C: conventional). Factors not related to the processing plants (e.g. genetic background of animals, transport, lairage) were standardized. In total, nine batches of about 150 pigs each were processed. Each batch was purchased at a commercial farm and randomly divided into three groups for delivery to the three processing plants. Meat quality was evaluated by measuring early post-mortem muscle pH and temperature as well as ultimate pH, meat colour (Minolta Chroma Meter and Japanese colour scale), filter paper score (FPS), electrical conductivity (EC) and drip loss. Plant C produced an inferior quality compared to plants A and B: meat was paler (C: 2.8 vs. A: 2.9 and B: 3.0 on the Japanese colour scale) and had higher drip losses (C: 5.2 vs. A: 4.8 and B: 4.9%). Meat colour hardly differed between plants A and B but waterholding properties were best at plant A as indicated by FPS (A: 2.4 vs. B: 2.8 vs. C: 3.3) and EC (A: 5.4 vs. B: 6.4 vs. C: 7.4 mS). It is concluded that processing plant may influence meat quality. Correlations between early post-mortem measurements and meat quality traits were low. Nevertheless, high carcass temperatures and low pH values early post-mortem were shown to lead to inferior meat quality.  相似文献   

6.
Pigs from crosses of a Piétrain (Pi) and a Large White×Piétrain (LwPi) heterozygous (Nn) boar lines with Landrace×Large White homozygous negative (NN) sows, were used to study the effect of halothane gene and pre-slaughter treatment on animal welfare and meat quality. A total of 83 gilts (47 NN and 36 Nn) were assigned to a long treatment (3 h 15 min transport and 12 h lairage) and 73 (39 NN and 34 Nn) to a short treatment (30 min transport and 2 h lairage). Heart rate was recorded throughout loading and transport. Blood samples were collected before loading, after transport, and at exsanguination to measure cortisol, creatine phospho-kinase (CPK) and lactate dehydrogenase (LDH). Carcasses were classified and commercial cutting was carried out. Meat quality was assessed on the Longissimus thoracis muscle by measuring electrical conductivity (PQM), colour (Minolta CR 200 and Japanese scale) and ultimate pH. Loin drip losses were assessed at 24 h. Halothane carriers showed a higher increase in cortisol levels after transport and exsanguination in the long treatment (P<0.05) as well as in LDH and CPK after exsanguination in the short treatment (P<0.05). In this treatment, halothane-free pigs recovered during lairage when comparing LDH and CPK increases after exsanguination to their increases after transport. No effect of the halothane gene on heart rate was observed. Pi sired pigs were leaner and had higher yields of leg and loin compared with LwPi sired pigs (P<0.001), but no differences in meat quality were observed between crosses. Halothane carriers had a higher estimated lean content (P<0.01) and shoulder and leg yields (P<0.01), but poorer meat quality than non-carriers (i.e. higher incidence of PSE meat, P<0.001). Although pre-slaughter treatment and halothane genotype did not significantly affect pHu, significantly higher L*, a* and b* values found in the short treatment and Nn individuals indicated paler meat. These results suggest that for improving meat quality and welfare the halothane gene should be removed from breeding schemes.  相似文献   

7.
The aim of this study was to investigate the effect of pre-slaughter fasting time, sex and feeding regime on the development of energy metabolism and pH in M. longissimus dorsi (LD) post-mortem in pigs. Two hundred and seventy pigs of the commercial Norwegian crossbreed Noroc (LYLD) were used involving two sexes (gilts and castrates), two feeding regimes (restricted and ad libitum) and four different fasting treatments: (F4) 4 h fasting, (F175) 17.5 h fasting on the farm, (FO175) 17.5 h fasting overnight at the abattoir, and (FO265) 26.5 h fasting overnight at the abattoir. Additionally the pigs experienced two different abattoir lairage times as fasting treatment F4 and F175 had a lairage time of 1.5 h, while fasting treatment FO175 and FO265 had a lairage time of 23.0 h. A short fasting time of 4 h led to a delayed degradation of glycogen, slow decline in pH and a lower ultimate pH45 h post-mortem (pHu) in the LD compared with a fasting time of 26.5 h which resulted in a rapid breakdown of glycogen and pH decline early post-mortem and a high pHu. Proglycogen was degraded in favour of macroglycogen under anaerobic conditions post-mortem. Feeding the animals in the morning before delivery if slaughtered the same day, results in low pH reduction rate and a low pHu compared with pigs fasted overnight either on farm or at the abattoir. Aiming a higher pHu in LD it should be recommended not to feed the pigs in the morning at the day of slaughter.  相似文献   

8.
Thirty Kivircik lambs were used to investigate effect of pre-slaughter treatment on certain haematological and biochemical parameters, carcass and meat quality characteristics. Lambs were divided into three treatments: 75 min transport and lairage for 18 h (TS-L18 h); 75 min transport and lairage for 30 min (TS-L30 min) and no pre-slaughter transport and lairage for 30 min (NTS). Treatment, as a main effect, did not influence haematological and biochemical parameters, but sampling time significantly affected these parameters, except total protein. Plasma cortisol concentration at exsanguination in TS-18 h, TS-30 min and NTS treatments were 117.34, 119.23 and 72.51 ng/ml, respectively. pH of longissimus dorsi muscle was higher in TS-L30 min than other treatments. TS-L30 min lambs had the highest shear force value, the lowest WHC and cooking loss. TS-L30 min treatment yielded the darkest meat immediately after cutting and 1 h later. Meat redness, yellowness and chroma values were similar in treatments.  相似文献   

9.
A total of forty Duroc–Landrace–Large White female pigs (90 ± 5 kg) were used to study the effects of different lairage times (0 h, 3 h, 8 h, 24 h) on welfare, energy metabolism and meat quality. The results showed that lairage time of 3 h led to a lower blood cortisol, a decreased drip loss and a delayed degradation of glycogen in muscles compared with pigs without rest, while lairage times of 8 h and 24 h resulted in a significant increase in pork toughness. It was concluded that three hours of lairage was appropriate to reduce pre-slaughter stress and obtain better meat quality for pigs transported for 4 h in winter, under the most frequent commercial conditions in Beijing, China. No lairage, or excessively long lairage time, might compromise animal welfare and meat quality.  相似文献   

10.
A total of 116 deliveries, comprising 15,695 commercial pigs delivered to five abattoirs, were surveyed during winter and summer. Information about on-farm fasting, transport duration and stocking density, and lairage time was collected. Cortisol, creatine phospho-kinase (CPK), and lactate, and DNA for halothane genotype were analysed in a subsample of pigs at exsanguination in every journey. Electrical conductivity (PQM) in semimembranosus muscle (SM) and carcass characteristics (Fat-o-Meater and skin damage) were measured in each carcass. pHu of SM was analysed in the laboratory in a subsample in every journey. Carcasses were identified as PSE or DFD based on PQM and pHu, respectively. The n gene frequency ranged among abattoirs from 54 to 8%. Mean lean content was 58.9% for nn, 57.3% for Nn, and 55.8% for NN pigs, though a difference of 2.5% lean was observed between two abattoirs with the same n gene frequency. A straight relationship of the incidence of serious PSE carcasses and n gene frequency was found. The overall incidence of serious PSE and DFD carcasses was 6.5 and 12.5%, respectively. A higher incidence of PSE carcasses was found in summer; in deliveries with <12 h on-farm fasting; with transport stocking densities >0.40 m(2)/100 kg pig; and in transports of <2 h duration. A higher incidence of DFD carcasses was found in winter; with transport stocking densities <0.40 m(2)/100 kg pig; transports of >2 h duration; and lairage times >9 h. Cortisol level in blood increased in winter and decreased after 12-18 h fasting time. A rise in the lactate concentration was observed in pigs transported in high stocking density (<0.40 m(2)/100 kg pig) and for a longer time (>2 h). All blood stress indices increase as increasing lairage time. Carcasses with more skin damage had higher levels of cortisol, CPK and lactate, and higher incidence of DFD meat, compared with non and low skin damage carcasses.  相似文献   

11.
A survey at five pigs' slaughterhouses was performed to investigate the effect of a quality assurance system, pre-slaughter conditions and slaughterhouse facilities on pork quality. Totally, 2246 pigs were included over four transports per slaughterhouse, i.e. two transports were produced according to a quality assurance system and the other two were conventional pigs. Meat quality was measured on 446 pigs. The pH in the longissimus dorsi muscle and the electrical conductivity in the semimembranosus muscle were measured 30min post-mortem. Twenty-four hours later pH and electrical conductivity in both the longissimus dorsi and the semimembranosus muscle were measured. Pigs managed according to a chain quality protocol showed an overall higher potential for improved meat quality. Differences in meat quality between the different slaughterhouses were also found, however they were dependent on muscle type and time of measuring. Influencing factors on pork quality seemed to be stocking density during transport, the handling during offloading the pigs from the truck, stocking density, and air temperature during lairage.  相似文献   

12.
Choi YM  Jung KC  Choe JH  Kim BC 《Meat science》2012,91(4):490-498
The effect of muscle cortisol concentration on muscle fiber characteristics and technological and sensory quality of pork was investigated. With the exception of the percentage of type IIA fibers, muscle fiber characteristics were not associated to cortisol levels. However, muscle cortisol concentration was positively associated with muscle pH(24h) (r = 0.23, P<0.05) and negatively associated with drip loss (r = -0.49, P<0.001), lightness (r = -0.24, P<0.05), shear force (r = -0.25, P<0.05), and texture profile analysis-hardness (r = -0.35, P<0.01). Additionally, the water-holding capacity of meat samples was affected by cortisol levels, with lower cortisol concentrations associated with less tender samples. These results indicate that the concentration of cortisol in the muscle is related with meat quality as well as the sensory quality of cooked pork.  相似文献   

13.
研究紫外辐照结合乳酸处理对冷冻藏猪肉品质的影响,明确该方法对藏猪肉冷冻贮藏的可行性。测定指标包括冷冻藏猪肉的肉色、质构、pH、TVB-N值。结果显示,在贮藏期内与对照组比,处理组L*值基本呈下降的趋势,a*值也低于对照组,且呈先升高后降低的趋势,与对照组差异显著(p<0.05);pH显著增加(p<0.05);处理组与对照组的滴水损失逐步增加;TVB-N值较对照组显著降低(p<0.05);试验后期,处理组与对照组在硬度和弹性方面出现显著差别(p<0.05)。结果表明:紫外照射结合乳酸处理对藏猪肉冷冻品质具有显著的影响,在工厂中使用时具有简便易行、提升品质的潜在作用。  相似文献   

14.
ABSTRACT:  This study evaluated the effect of ultimate pH (pHu) of pork on shelf life based upon microbial growth, drip loss, and oxidative rancidity (2-thiobarbituric acid [TBA] procedure) in vacuum-packaged loins stored at 4 °C. Glucose and lactate concentrations of the pork loins were also measured. Thirty-six pork loins (pH = 5.56 to 6.57) were collected at a commercial slaughter facility 1-d postslaughter. All pigs were from the same genetic line. Loins were grouped by pH (group: pH range): A: 5.55 to 5.70, B: 5.71 to 5.85, C: 5.86 to 6.00, D: 6.01 to 6.15, and E: > 6.16. They were analyzed at days 0, 6, 14, 24, and 34. For aerobic plate counts, groups A and B were significantly lower than C through E, while psychrotrophic or Enterobacteriaceae counts of groups A and A through C were significantly lower than groups B through E and D and E, respectively. Lactic acid bacteria counts were not significantly influenced by pHu. Group A had higher glucose concentrations than groups C through E and higher lactate concentrations than groups D through E on most sampling days. Group A had a higher TBA value than group E at days 0 and 34. Group A displayed greater drip loss than groups D and E at day 6 and groups B through D on days 24 and 34. Based on the microbial and drip loss results, a pork loin pHu of 5.8 to 5.9 appears to be optimum to provide a vacuum-packaged shelf life of at least 24 d with minimum drip loss.  相似文献   

15.
The influence of the accumulated exudates released from pork loin of itself on the quality characteristics of fresh and freeze-thawed pork during cold storage was investigated. Pork loins were divided into four groups (fresh pork with exudates, fresh pork without exudates, freeze-thawed pork with exudates and freeze-thawed pork without exudates) and stored at 1.0 °C for 7 days. Exudate amount increased due to freeze-thawing and with storage, and most quality traits such as drip loss, cooking loss, tenderness, lightness, redness, and moisture content were affected by freeze-thawing (p < 0.05). Freeze–thaw increased drip loss but decreased moisture content, cooking loss, tenderness, lightness and redness of meat (p < 0.05). Microbial growth was solely affected by exudate removal and the removal of initial exudates decreased microbial growth (p < 0.05). Exudates were positively correlated with total protein content and total plate count but negatively correlated with pH and cooking loss. Therefore, removing meat exudates and avoiding freeze can slow down the quality deterioration of pork during cold storage.  相似文献   

16.
Risk assessment of DFD meat due to pre-slaughter conditions in pigs   总被引:1,自引:0,他引:1  
A polychotomous logistic regression model was used to identify and assess the risk factors for pork becoming dark, firm and dry meat (DFD). A total of 116 deliveries, comprising 3075 commercial pigs delivered from different farms to five commercial Spanish pig abattoirs were surveyed. The DFD condition was described as an ordinal response variable (normal, moderate and serious) based on measurements of pH24 in the Semimembranosus muscle. The abattoir, the floor of the lorry, the season, the gender, and the stocking density during transportation influenced the risk of DFD, as well as on-farm fasting time, lairage time and estimated carcass lean content. No effect of the RYR1 gene in the risk of DFD was found. Abattoirs should be especially careful with females slaughtered in winter, where the risk of serious DFD is 4.6% higher than with males slaughtered in summer. The risk of DFD increased with high stocking density and lairage time, and with on-farm fasting times longer than 22 h. Our results revealed that lowering the stocking density from 0.37 to 0.50 m2 per 100 kg pig during transport would increase the risk of DFD pork by 11%.  相似文献   

17.
Fluid (purge) losses and pH of turkey breast meat were measured (n=45). During the 24 h between slaughter and analysis in the laboratory, fluid loss during transport was 0.54 S.D. 0.43%. Mean pH at 24 h post-mortem was 5.97 ± 0.12. Mean cooler drip from sliced meat in the following 72 h was 4.31 ± 1.91%. Transport loss was correlated with cooler drip, r=0.47, P < 0.001. Transport loss was correlated with pH, r= −0.42, P < 0.01. Cooler drip was correlated with pH, r= −0.35, P < 0.02. At 24 h post-mortem, slices of turkey pectoralis muscle 1 mm thick were illuminated with linearly polarised light. Spectra were measured from 400 to 700 nm in various orientations: using transmitted or reflected light, with polarised light parallel or perpendicular to the long axes of muscle fibers, and with a rotary analyzer parallel or perpendicular to the polariser. For illumination parallel with the long axes of muscle fibers, and the analyzer perpendicular to the polariser, reflectance was correlated with fluid loss during transport to the laboratory (R=0.60, P < 0.01, using 490, 520 and 580 nm), with sample pH (R=0.46, P < 0.05, using 570, 580 and 550 nm), and with cooler drip losses (R=0.55, P < 0.01, using 450, 490 and 460 nm). Overall, reflectance was more useful than transmittance for predicting pH-related fluid losses.  相似文献   

18.
The potential of near-infrared spectroscopy (NIRS) measurements early post mortem was investigated to predict ultimate drip loss, colour, tenderness and intra-muscular fat of pork. Three locations (M. longissimus thoracis, M. longissimus lumborum and M. semimembranosus) in 102 pig carcasses were tested at the end of the slaughter line. A priori variation in pork quality was introduced using an experimental design covering: genotype, lairage time, pre-slaughter handling and day of slaughter. At 1 h post mortem a diode array VIS/NIR instrument (Zeiss MCS 511/522, 380-1700 nm) equipped with a surface fibre optic probe was used and at 1 day post mortem ultimate pH, drip loss, colour and shear force was measured on similar locations. Results indicated that it was possible to predict intra-muscular fat content (correlation (R(2) of 0.35 with multiple linear regression), standard error of prediction (SEP)=3.6 g/kg), but the configuration has to be refined for on-line application (bigger aperture). For drip loss no correlation was achieved with the PLS method. Even extremes (low drip loss (<2.5%) or high drip loss (>4.5%)) in drip loss were not discriminated. Predicting drip loss with NIRS early post mortem is not successful, although NIRS in the slaughter line has potential as a fast predictor of intra-muscular fat. Possibilities for using the NIRS technique to get to know more about muscle metabolism and post mortem changes are promising.  相似文献   

19.
The effect of lairage time on meat quality was investigated when crossbred pigs were subjected to low stress pre-slaughter handling, where pigs were treated in mixed groups of 15 from the farm to group CO(2) stunning, and where electric goads were not used at any time. Two experiments were carried out, one in spring (n=270) using very standardised conditions and one producer, and one in summer (n=630) using a representative randomly chosen sample of producers. In the first experiment three lairage times were used, less than 30 min (average 26 min), 90 min (average 83 min) and more than 150 min (average 170 min) and no showering. The pH and temperature were measured in the m. longissimus dorsi at various times post mortem, and colour (L(*), a(*), b(*)), internal reflectance and drip loss the day after slaughter. Sensory evaluation was carried out on 16 randomly chosen samples from the shortest and longest lairage time groups. Drip loss, pH(ultimate) and internal reflectance were also measured in the m. biceps femoris and pH(ultimate) and internal reflectance in the m. semimembranosus. Finally, pH(ultimate) was measured in the m. semispinalis capitis. In the second experiment only two lairage times were used, less than 30 min (average 17 min) and more than 130 min (average 150 min) and with intermittent showering and only a subset of the meat quality measurements were made. Lairage time had no effect on any of the meat quality parameters measured in experiment 1. In experiment 2 the shortest lairage time led to a higher temperature in the m. longissimus dorsi at 2 min post mortem, a higher drip loss in the m. biceps femoris and higher internal reflectance values in both muscles the day after slaughter. The differences were, however, very small and may have been an effect of showering.  相似文献   

20.
Longissimus dorsi samples (685) collected at four processing plants were used to develop prediction equations for meat quality with near infrared spectroscopy. Equations with R(2)>0.70 and residual prediction deviation (RPD)≥2.0 were considered as applicable for screening. One production plant showed R(2) 0.76 and RPD 2.05, other plants showed R(2)<0.70 and RPD<2.0 for drip loss %. RPD values were ≤2.05 for drip loss%, for colour L*≤1.82 and pH ultimate (pHu)≤1.57. Samples were grouped for drip loss%; superior (<2.0%), moderate (2-4%), inferior (>4.0%). 64% from the superior group and 56% from the inferior group were predicted correctly. One equation could be used for screening drip loss %. Best prediction equation for L* did not meet the requirements (R(2) 0.70 and RPD 1.82). pHu equation could not be used. Results suggest that prediction equations can be used for screening drip loss %.  相似文献   

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