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1.
Moderately PSE (pale, soft, exudative) and moderately DFD (dark, firm, dry) pork was examined by x-ray diffraction for interfilament separation, by differential interference contrast microscopy for interfiber area, and was centrifuged to measure water holding capacity (WHC). Internal reflectance spectra were measured by fiber optics. For PSE to DFD pork, filament separation ranged from 39 to 48 nm, interfiber area from 42 to 3%, and WHC from 49 to 64%, respectively. The correlation of reflectance with interfilament separation varied considerably with wavelength (reaching r = -.83 at 680 nm, P less than .005). The correlation of reflectance with interfiber area was more uniform across the spectrum (reaching r = .90 at 450 nm, P less than .005), as was the correlation of reflectance with WHC (reaching r = -.80 at 400 nm, P less than .005). At 24 h postmortem, fiber-optic spectrophotometry may be used as a rapid, nondestructive method to predict WHC and potential fluid losses from commercial pork with a moderate range from PSE to DFD. Interfiber area was correlated negatively with filament lattice area and WHC, but no significant correlation was found between filament lattice area and WHC. Filament separation was decreased only slightly by centrifugation. These results indicate that at 24 h postmortem the extra fluid released from PSE pork already has been lost from the myofilament lattice and is awaiting release from compartments downstream such as interfiber and interfascicular spaces.  相似文献   

2.
The purpose of the present study was to investigate the variations in histochemical characteristics of muscle samples segregated according to metabolic rates (MR) and pork quality attributes. A total of 231 crossbred Duroc x (Yorkshire x Landrace) pigs was evaluated. Samples of the LM were taken to evaluate histochemical characteristics, postmortem MR, and meat quality. Samples were classified into fast, normal, and slow MR groups based on muscle pH at 45 min and R-value. Drip loss and lightness (L*) were used to assign samples to 1 of 4 quality classes. Pale, soft, and exudative pork belonging in the fast group had the greatest (P < 0.05) percentage of type IIb fibers, and RSE (reddish-pink, soft, and exudative) pork belonging in the fast group had a similar tendency. Additionally, RFN (reddish-pink, firm, and nonexudative) pork belonging in the normal group showed a lower (P < 0.05) percentage of type IIb fibers than PSE or RSE, regardless of MR, and DFD pork had the lowest (P < 0.05) percentage of type IIb fibers. In general, the fast-glycolyzing PSE pork with the lowest pH at both 45 min and 24 h had greater percentages of type IIb fibers than the fast-glycolyzing RFN pork. There were more fiber-type composition differences between quality classes in pork undergoing a fast rate of metabolism compared with pork undergoing a normal rate of metabolism. It can be concluded that muscle histochemical characteristics are associated with early postmortem MR, the extent of glycolysis, and, thereby, pork quality; however, these effects are limited to the pigs exhibiting a fast glycolytic rate.  相似文献   

3.
Effects of the halothane genotype and slaughter weight on texture of pork   总被引：4，自引：0，他引：4  
The objective of this study was to investigate the effects of the halothane (HAL) genotype, slaughter weight (SW), and the HAL x SW interaction on compositional and textural traits of raw and cooked pork. Pigs were bred to exhibit one of the three HAL genotypes (NN, Nn, and nn) with otherwise equivalent genomes. The nn halothane reactors are known to typically produce PSE pork, whereas NN pigs do not typically produce PSE pork. Pietrain x Large White gilts and boars, all with verified Nn genotype (by DNA test), were mated to obtain F2 littermates of the three HAL genotypes. These pigs were slaughtered at either 101 +/- 3 ("light") or 127 +/- 3 ("heavy") kg BW and were evaluated for longissimus muscle traits. The pH at .5 h after death (pH1) was 6.35, 6.13, and 5.68 in NN, Nn, and nn pigs, respectively. Sarcomere length was greater in nn than in NN and Nn pigs (1.94 vs 1.83 and 1.85 microm, respectively). Mechanical resistance was higher in nn than in NN pigs for both raw and cooked meat. Meat from nn pigs was judged by a trained panel to be less rough, more cohesive, harder, more fibrous, less granular, more elastic, and less easy to swallow than meat from NN pigs. For most traits under study, the heterozygotes were intermediate between the homozygotes but closer to NN than to nn pigs. Muscle from heavy pigs had longer sarcomeres and less moisture than muscle from light pigs. The n allele of the HAL gene unfavorably affects pork texture, and this effect is maintained throughout the range of 101 to 127 kg BW.  相似文献   

4.
Ultraviolet light (365 nm) was directed at an angle of 45 degrees onto meat samples in a circular aperture (3 cm diameter). Fluorescence emissions were measured with a monochromator and a photomultiplier tube. Intact tendons and elastic ligaments had a strong fluorescence emission peak around 440 to 450 nm and only weak fluorescence around 510 nm. Tissues such as lean meat and adipose tissue that contain a matrix of reticular fibers (Type III collagen) had very low fluorescence around 440 to 450 nm so that their peak emittance was the weak fluorescence peak at 510 nm. The 510/440 nm ratio of fluorescence emissions was measured in comminuted meat samples containing varying mixtures of lean meat and gristle and varying mixtures of muscles with a high and low gristle content. The 510/440 nm ratio was correlated with the ratio of lean meat/gristle (r = .96, P less than .005). The 510/440 nm ratio was correlated with the ratio of longissimus/shank meat (two trials; r = .93, P less than .01; and r = .94, P less than .005). Results were only slightly changed when samples had dry surfaces or when samples were mixed with adipose particles. The relationship between the area of gristle in the samples and the 510/440 nm ratio was curvilinear with the greatest sensitivity to the fewest gristle fragments.  相似文献   

5.
Glycolytic potential of red, soft, exudative pork longissimus muscle   总被引：7，自引：0，他引：7  
Red, soft, exudative (RSE) pork is red as "normal" pork and exudative as PSE pork. The origin of RSE quality is unknown. In the present study, we determined whether the occurrence of RSE pork is related to the presence of the RN (Rendement Napole) gene. A glycolytic potential [= 2 x (glucose + glycogen + glucose-6-phosphate) + lactate] of > 180 micromol lactate/g of meat was used as indicator for presence of the RN gene. At 1 d postmortem, pork loin samples were collected at a commercial slaughter plant, and meat quality characteristics and glycolytic potential were determined. Glycolytic potential of RSE pork (n = 42) was higher (P < .01) than that of RFN (red, firm, nonexudative) pork (n = 25): 137 vs 110 micromol lactate/g of muscle. The glycolytic potential of PSE pork (n = 28) was 161 micromol lactate/g of muscle, which was higher (P < .01) than the glycolytic potential of RFN or RSE pork. Using a glycolytic potential of 180 micromol lactate/g of muscle as suggestive for the presence of the RN gene, four (10%) of the RSE samples were from RN carriers. By the same criterion, the PSE group contained nine (32%) RN gene carriers. These results suggest that the occurrence of RSE quality is not related to the presence of the RN gene.  相似文献   

6.
Spectroscopy using four types of fiberoptic probes and a sensor at wavelengths of 400 to 1,100 nm was evaluated to assess porcine fat quality. The shapes of the spectrum for the leaf fat with white color and various firmnesses differed with the type of probe: surface, contact, insertion, or transmittance. The internal reflectance ratio using the insertion probe at wavelengths from approximately 600 to 1,000 nm was positively correlated with the hardness, melting point, and saturated fatty acid content of the fat, but it was negatively correlated with the refractive index and polyunsaturated fatty acid content. The correlations between the internal reflectance ratio using the insertion probe and the monounsaturated fatty acid content were strong only near 1,100 nm. Surface reflectance at more than 650 nm was negatively correlated with refractive index. Transmittance at almost all wavelengths showed positive correlations with monounsaturated fatty acid content, but it was negatively correlated with hardness, melting point, and saturated fatty acid content. The interactance using the contact probe did not have a significant correlation with any physiochemical characteristics. The strongest relationships for hardness, refractive index, saturated fatty acid content, monounsaturated fatty acid content, polyunsaturated fatty acid content, and melting point were obtained at 650 nm (r = .88), 660 nm (r = -.91), 645 nm (r = .73), 1,095 nm (r = .68), and 930 nm (r = -.76), respectively, using the insertion probe and 1,050 nm (r = -.79) using the transmittance probe (P<.05). These results indicated that fiber-optic methods were rapid and useful techniques for the evaluation of porcine fat quality.  相似文献   

7.
The following methods of insensitisation were tested for their effects on muscle pork quality: Electrocoma, 75 V, 15 sec; Electrocoma following intensive electrical stimulation and irritation of various parts of the animals's body, using the insensitising forceps; Dart gun insensitisation. Also tested was the action of muscle relaxants on pork quality. Minor deviation from proper practice of electrical insensitisation was found to cause no significant deterioration in cutlet muscle and ham muscle quality. However, intensive irritation immediately before insensitisation caused higher percentages of PSE (16.7 per cent) and DFD (16.7 per cent). Dart gun insensitisation was quite often followed by poorer quality in the form of watery and bright pork (25.0 per cent). This had detrimental consequences for boiled ham processing (higher loss rates). Sensorial assessment of boiled ham obtained from animals in various categories did not reveal any significant discrepancy between the above techniques. When muscle relaxants were used, muscle pork quality of pigs relaxed by means of succicholine dichloride was much better than that in animals to which electrical insensitisation had been applied. Characteristics of such better quality included slower decline in pH over 45 minutes after death and lower drip loss.  相似文献   

8.
The objective of the current study was to create an in vitro model that duplicated the development of PSE pork. Postrigor pork chops with various pH values and normal color were vacuum-packaged, and heated at approximately 42 degrees C for various times (0, 15, 30, 60, 120, or 240 min), or heated to temperatures that occur early postmortem (34, 37, 39, or 42 degrees C for 60 or 120 min) in a water bath. Chops were cooled and allowed to bloom, after which changes in Minolta and Hunter color values were assessed, and purge loss was determined. Warming postrigor pork with normal color and pH to early postmortem body temperature for various times successfully duplicated the characteristics of PSE pork. After 60 to 120 min at 42 degrees C or above, chops with pH < 5.8 lightened until L values were similar to those typical of PSE pork (Minolta L = 61.0). Change in chop color depended on length of time the samples were warmed, as well as on pH. Below 34 degrees C, temperature had no (P > or = 0.28) effect on color (Minolta L, a, b, and Hunter L*, a*, b*); however, at higher temperatures, color change depended on pH and warming time. A comparison of the time and temperature relationships for changes in lightness and purge suggested that the mechanisms of the two processes are not identical. The similarities in the dynamic range of color change, change in absolute color values, and time frame for changes in vitro and in vivo suggest similarity of the processes creating PSE in a carcass and in the in vitro model.  相似文献   

9.
In an effort to understand the relationship between muscle fiber type, live weight, genotype, and PSE development, enzyme-linked immunosorbent analyses were used to evaluate myosin heavy chain (MyHC) isoform content in the longissimus muscle of pigs differing in halothane gene status (nn, homozygous mutant; Nn, heterozygous; NN, homozygous normal) that were slaughtered at three different weights (100, 120 and 140 kg). Pigs carrying the n gene (Nn and nn) exhibited more IIB MyHC and less slow type I MyHC than those pigs free of the n gene, while NN pigs had greater amounts of IIAX MyHC. The relative abundance of IIB and IIAX MyHC in muscle of all pigs studied was strongly negatively correlated (r=−0.834). Heavier pigs (140 kg) had the greatest amounts of slow and IIA MyHC. Across all genotypes, the relative abundance of IIB MyHC and muscle pH at 45 min postexsanguination (pH45) was negatively correlated (r=−0.418). In addition, the relative amount of slow was positively correlated with pH45 (r=0.386). Because muscle of homozygous nn positive pigs exhibited similar IIB/slow MyHC ratios to that of heterozygous Nn pigs, yet less desirable pH45 values and ultimate meat quality scores argues against a role of MyHC content per se in contributing to PSE development. However, these data do not preclude that those pigs with greater amounts of IIB MyHC are more ‘susceptible’ to adverse pork quality development than those pigs with less IIB MyHC.  相似文献   

10.
Pale, soft, exudative (PSE) pork occurs, for the most part, from environmental stress on the pig. Amino acid intake may be related to stress susceptibility through hormone and neurotransmitter induction. Two experiments were conducted to determine whether supplementation of 5 g of tryptophan (TRP) or 10 g of tyrosine (TYR) per kilogram of a 14% CP diet would alter the response of pigs to stress as measured by hypothalamic neurotransmitter concentrations and incidence of PSE. Twenty-four (Exp. 1) and 36 (Exp. 2) 92-kg pigs were offered one of three diets: control, TRP-, or TYR-supplemented for 5 d before slaughter. Dietary TRP or TYR supplementation in Exp. 1. doubled (P less than .05) plasma TRP and TYR concentrations, respectively, and increased (P less than .05) 5-hydroxytryptamine, dihydroxyphenyl ethylamine, dihydroxyphenyl acetic acid, and homovanillic acid concentrations in the hypothalamus. Pigs that exhibited stress at slaughter had lower (P less than .05) hypothalamic concentrations of epinephrine, norepinephrine, and 5-hydroxytryptamine. In Exp. 2, pigs were trucked 55 km to a commercial meat packing facility and slaughtered without a rest period. This handling procedure was designed to invoke a high incidence of PSE pork and thus be a strong test of treatments. Supplemental dietary amino acids seemed to alter the frequency distribution of the severity of PSE pork. These data indicate that dietary manipulation of amino acid precursors of neurotransmitters may offer a practical means of reducing stress response in swine.  相似文献   

11.
为分析大约克猪肌糖原含量与胴体品质及肉质的相关关系,将18头体重35 kg左右的大约克猪在相同条件下饲养,体重达100 kg时屠宰,测定肌糖原、胴体品质及肉质。结果表明,肌糖原含量与胴体品质及肉质性状间相关程度有强有弱,相关系数有正有负。肌糖原含量与部分胴体性状相关性显著,与瘦肉率显著正相关,相关系数为0.524（P〈0.05）;与脂肪率显著负相关,相关系数为-0.520（P〈0.05）。肌糖原含量与部分肉质性状相关性显著,如与pH1显著正相关,相关系数为0.613（P〈0.05）,与其他肉质性状相关较弱。肌糖原含量与背最长肌甘氨酸和亚油酸含量极显著正相关,相关系数分别为0.598（P〈0.01）和0.621（P〈0.01）。  相似文献   

12.
One hundred seventy-seven pigs were used to determine the interaction effects of fasting and length of transport prior to harvest on pork muscle quality. The study design was a 2 x 2 x 3 factorial, which involved two genetic sources, fasting (F) or no fasting (N) of pigs 48-h prior to harvest, and three transport times (0.5, 2.5, or 8.0 h) on a semitrailer to the packing plant. Genetic source was a significant source of variation (P < 0.05) for most composition and muscle quality variables. Fasting reduced hot carcass weight 3.6% (P < 0.05), but length of transport did not affect hot carcass weight (P > 0.05). There were no differences (P > 0.05) in percent lean among fasting and transport treatments. Fasted pigs had higher longissimus dorsi (LD) ultimate pH (pHu), darker lean color, higher marbling score and lower 7-d purge loss, 24-h drip loss, and cooking loss (P < 0.05) than nonfasted pigs. Meat from pigs that were transported 8.0 h had lower glycolytic potential (GP), higher LD and semimembranosus (SM) pHu, darker lean color, and lower L*, 7-d purge loss, 24-h drip loss, cooking loss, and shear force values than meat from pigs transported 0.5 h (P < 0.05). Meat from pigs transported 2.5 h had higher LD and SM pHu and lower L*, 7-d purge loss, 24-h drip loss, and cooking loss than meat from pigs transported 0.5 h (P < 0.05). Meat from pigs transported 8.0 h had higher LD pHu and color scores and lower L* and cooking loss than meat from pigs transported 2.5 h (P < 0.05). The fasting x transport interaction was significant for SM pHu, L*, color score, and drip loss. Fasting improved SM pHu, L*, color score, and drip loss for pigs that were transported 0.5 h (P < 0.05), but when pigs were transported for 2.5 h or 8.0 h, fasting had little or no effect on these muscle quality traits. Fasting lowered GP and increased LD pHu for pigs from the genetic source with the higher initial pork quality (P < 0.05), while fasting had no effect on pork quality for pigs from the genetic source with the lower initial pork quality (P > 0.05). Longer transport times resulted in lower GP and higher LD pHu regardless of genetic source. Fasting and length of transport each had positive effects on pork quality, but length of transport effects was greater in magnitude. When pigs were transported for 0.5 h, fasting for 48 h prior to harvest improved pork quality, but when pigs were transported 2.5 or 8.0 h, fasting had little effect on pork quality.  相似文献   

13.
Malignant hyperthermia (MH) and the mycotoxin cyclopiazonic acid (CPA) are each associated with abnormal calcium homeostasis in skeletal muscle, a key underlying factor in the development of pale, soft, and exudative (PSE) pork. To determine whether the natural presence of CPA in livestock feed ingredients contributes to the varying incidence of PSE in the pork industry, various levels of CPA (.1 to 50 mg/kg of diet) were included in the diets of market weight hogs (n = 52) of defined malignant hyperthermia genotype (NN = normal, Nn = a MH carrier, and nn = MH-positive). Animals with two copies of the MH mutation (nn) displayed improved live animal performance compared with NN and Nn animals (increased feed intake, average daily gain, and feed efficiency) but yielded lower quality loin chops as indicated by lower 45-min pH (P<.01), higher Commission Internationale de l'Eclairage (CIE) L* color coordinate values (P<.05), and higher drip losses (P<.01). The effects of CPA varied. In the first feeding trial, conducted under normal outside temperatures (2 degrees C), CPA had no effect (P> .2) on either live animal performance or meat quality. During the second trial, conducted under extreme outside temperatures (-18 degrees C), CPA-dependent reductions (P<.05) in feed intake, average daily gain, and 45-min pH in nn hogs support the possibility of interactions between malignant hyperthermia and dietary CPA on skeletal muscle calcium homeostasis and the development of PSE pork. These results suggest that this interaction may require stressful environmental conditions or the ingestion of CPA doses much higher than occur under natural conditions.  相似文献   

14.
We studied the relationships between the shear-force value and physical and structural properties of the intramuscular connective tissue (IMCT) in six classes of porcine skeletal muscle to elucidate the contribution of IMCT to toughness of raw pork. The shear-force value of raw pork correlated significantly with that of the IMCT model prepared from each class of skeletal muscle ( P  < 0.05). The correlation suggested that the variable toughness of pork was caused by the mechanical strength of the endomysium and perimysium. The thickness of the secondary perimysium correlated significantly with the shear-force value of raw pork ( P  < 0.05) and with that of the IMCT model ( P  < 0.05). The shear-force value of raw pork correlated significantly with the total amount of collagen ( P  < 0.05) but not with the heat-solubility of collagen. We concluded therefore that the thickness of the secondary perimysium determines the mechanical strength of IMCT and contributes to toughness in raw pork.  相似文献   

15.
Information on the effect of road transportation conditions and lairage times on the meat quality of pork under South African conditions is very sparse. In this investigation, the effects of 2 road conditions (rough road with frequent stops - A; smooth road, few stops - B) and 2 lairage holding periods (2 h and 24 h) on the physical meat quality attributes of commercially produced pigs during summer (ambient temperatures > 30 degrees C) in the Western Cape (South Africa) were investigated. Pig meat from pigs transported on a road that caused more stress (A), had lower pH 45 (measured 45 min post mortem) values after 2 h lairage than pigs transported over a smoother road. Pigs B had a lower muscle pH 24 (measured 24 h post mortem) than group A, indicating that they had more glycogen reserves available for post mortem glycolysis. Road conditions A were more stressful resulting in a higher incidence of PSE pork, as shown by the percentage drip loss and the L* values. When the lairage period was increased to 24 h prior to slaughter, pigs transported under road conditions A had time to replenish their energy reserves and the pH 45, drip loss and L* values were within an acceptable range. However, pigs transported under road conditions B had lower pH 45 and higher pH 24 values, indicating that the lairage period was too long and that energy reserves were depleted in order to adapt to the stressful conditions. Results from this investigation indicate that improvement of the transport/road conditions will result in better pork quality.  相似文献   

16.
The authors have revealed the main value characteristics of pork production by testing in five different types of pig the volume of contractile and collagen proteins, that of proteoglycans, the constituents of blood and the enzymes of the blood plasma. The contractile proteins of the muscle tissues basically determine the quality of pork. The same applies to the water retention capacity, colloidal characteristics and glycogen content of meat. The amount of contractile proteins has decreased in the best meat producing types of pig. Parallel with the decrease of white meat, and with the increase in the volume of ham, chop and chuck the contractile protein content of muscles decreased. The scientific fact according to which there is a certain correlation among the changes in the volume of contractile proteins, blood sugar level, blood serum CPK and the intensity of activity of the LDH enzymes promotes the qualifying of live animals and the work of the geneticists aiming at the increasing of the contractile protein content of the muscle tissues of pigs by selection. According to tests carried out by us the primary cause of PSE changes is a decreased volume of contractile proteins. Increased stress sensitivity and all the other factors have but a secondary importance and are all consequential. The decrease in the quantity of contractile proteins or--it is better to put it this way--the lack of the proper amount of such proteins characterizing a fully developed pig's organism is caused by the nowadays usual breeding technologies and can be well explained by those selection activities which aim at a one-sided kind of pork production.  相似文献   

17.
肌糖原含量与猪生产性能、胴体品质及肉质性状间的关系   总被引：1，自引：0，他引：1  
试验比较2个不同基因型猪肌糖原含量、生长性能、胴体品质和肉质的差异,并分析肌糖原含量与生长性能、胴体品质及肉质之间的相关关系。将7头纯种汉普夏阉公猪体重为(19.48±1.1)kg和6头长撒公猪体重为(20.5±1.5)kg在相同条件下进行单圈饲养,到体重达100kg左右时屠宰,并测定肌糖原、胴体品质和肉质。结果表明:汉普夏猪比长撒猪有较高的日增重(P>0.05),较高的肌糖原含量(P<0.05);长撒猪有较高的背膘厚(P<0.01),较低的屠宰率(P<0.05)、眼肌面积和瘦肉率(P<0.01);汉普夏猪有较低的pH2(P<0.05)、剪切力(P<0.05)和b值(P<0.01),但滴水损失和失水率(P<0.05)高于长撒猪。相关分析结果表明:肌糖原含量与眼肌面积和瘦肉率呈正相关,与剪切力、滴水损失、平均日增重、b值、pH1和pH2呈负相关,而与平均日增重、屠宰率和胴体长相关性不大。这表明肌糖原含量是影响猪胴体品质和肉质的一个重要因素。  相似文献   

18.
The M. longissimus dorsi of 171 pigs were histologically examined for pathological signs. Acute hyaline-plaque degenerations and necrosis (hsD/N) in various degrees of manifestation were recorded from 42.7 and hyaline transverse ligaments (hQb) from 22.8 per cent of all cases. The occurrence of hsD/N following container transport was lower with significance (33.3 per cent) than that following lorry transport (50.5 per cent). The form of transport failed to have any substantive effect on the occurrence of hQb, the figures being 20.5 per cent for container and 24.7 per cent for lorry. Short resting periods, between 0.5 and 1.2 hours, were followed with significantly higher occurrence of hsD/N, as compared to longer resting periods, between five and eight or 23 hours. These pathological findings were not further reduced by extending the resting period from something between five and eight to 20 hours. The pathological hsD/N and hQb findings were recordable from both PSE pork (hsD/N = 51.4 per cent, hQb = 25.7 per cent) and from pork without any quality shortcomings (hsD/N = 39.7 per cent, hQb = 22.1 per cent), but the number of hsD/N cases in the context of PSE pork tended to be higher than that in high-quality pork. No sex dependence was established. The results are discussed under the aspect of aetiopathogenesis of stress-borne myopathy.  相似文献   

19.
The present experiments were conducted to determine whether improved beef longissimus shear force methodology could be used to assess pork longissimus tenderness. Specifically, three experiments were conducted to: 1) determine the effect of belt grill (BG) cookery on repeatability of pork longissimus Warner-Bratzler shear force (WBSF), 2) compare the correlation of WBSF and slice shear force (SSF) with trained sensory panel tenderness ratings, and 3) estimate the repeatability of pork longissimus SSF for chops cooked with a BG. In Exp. 1 and 2, the longissimus was removed from the left side of each carcass (Exp. 1, n = 25; Exp. 2, n = 23) at 1 d postmortem and immediately frozen to maximize variation in tenderness. In Exp. 1, chops were cooked with either open-hearth electric broilers (OH) or BG, and WBSF was measured. Percentage of cooking loss was lower (P < 0.001) and less variable for chops cooked with a BG (23.2%; SD = 1.7%) vs. OH (27.6%; SD = 3.0%). Estimates of the repeatability of WBSF were similar for chops cooked with OH (0.61) and BG (0.59). Although significant (P < 0.05), differences in WBSF (4.1 vs. 3.9 kg) between cooking methods accounted for less than 5% of the total variation in WBSF. In Exp. 2, the correlation of SSF (r = -0.72; P < 0.001) with trained sensory panel tenderness ratings was slightly stronger than the correlation of WBSF (r = -0.66; P < 0.001) with trained sensory panel tenderness ratings, indicating that the two methods had a similar ability to predict tenderness ratings. In Exp. 3, duplicate samples from 372 carcasses at 2 and 10 d postmortem were obtained, cooked with BG, and SSF was determined. The repeatability of SSF was 0.90, which is comparable to repeatability estimates for beef and lamb. Use of BG cookery and SSF could facilitate the collection of accurate pork longissimus tenderness data. Time and labor savings associated with BG cookery and the SSF technique should help to decrease research costs.  相似文献   

20.
The relationships between glycolytic potential and growth performance, carcass traits, and pork quality were investigated in a group of 72 pigs from the same genetic line. Glycolytic potential (GP) was determined on live-animal biopsy samples and postmortem samples taken from the longissimus muscle, and free glucose concentration was measured on the exudate from the longissimus muscle taken postmortem. The mean live-animal and postmortem GP and free glucose values were 201.6 micromol/g (range = 113.8 to 301.1), 149.8 micromol/g (range = 91.0 to 270.5) and 110.1 mg/dL (range = 30.0 to 406.0), respectively. Correlations between live-animal and postmortem GP and free glucose ranged from 0.47 to 0.70; however, all three measures were weakly related to growth and carcass traits (r = 0.03 to -0.22; P > 0.05). Correlations of GP and free glucose values with fresh pork quality measurements were moderate (r = 0.23 [P < 0.05] to -0.63 [P < 0.001]). Regression analysis suggested that a one standard deviation increase in live-animal and postmortem GP and free glucose resulted in an increase in L* values (0.99, 1.32, and 2.05, respectively) and drip loss (0.85, 1.10, and 1.39 percentage units, respectively), as well as a decrease in ultimate pH (0.05, 0.11, and 0.16, respectively). Correlations between GP and cooking loss and tenderness and juiciness scores ranged between 0.16 (P > 0.05) to 0.34 (P < 0.01). Free glucose concentration showed no relationship (P > 0.05) with cooking loss, tenderness, and juiciness. Regression analysis suggested that a one standard deviation increase in live-animal and postmortem GP increased cooking loss (1.26% and 1.65%, respectively) and would improve taste panel tenderness (0.54 and 0.44, respectively) and juiciness (0.40 and 0.48, respectively) scores. Increasing GP and free glucose was also associated with decreased longissimus fat and protein, and increased moisture contents (r = 0.14 [P > 0.05] to -0.45 [P < 0.001]). Overall, relationships with fresh meat quality characteristics were stronger for free glucose values than either live-animal or postmortem GP. Results from this study indicate that decreasing longissimus GP and free glucose concentrations may improve pork color and water-holding capacity.  相似文献   

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