Sensory and functional meat quality characteristics of pork derived from three halothane genotypes

The effect of the halothane gene in pigs on the meat and sensory qualities thereof were determined. Meat derived from 60 Landrace×Large White pigs of three halothane genotypes was used. The sensory qualities, cooking loss, colour, shear value and proximate analysis of the cooked pork loin roasts were determined. The three genotypes did not differ significantly (P>0.05) with regard to the colour of the cooked meat, percentage cooking loss and percentage moisture. There were significant differences (P<0.05) between the genotypes in the percentage protein, ash and fat. Meat from the three genotypes also differed significantly (P<0.05) in juiciness, an analytical sensory panel scored the juiciness of meat from the NN-genotype the highest with a value of 71.3 when using a structured line scale. Meat from the nn-genotype had the lowest score for juiciness (62.8). Meat from the three genotypes did not differ significantly (P>0.05) with regard to tenderness, pork flavour and no mealiness. Correlation values showed a positive correlation (r=0.46, P<0.05) between juiciness and tenderness. These results indicate that the inclusion of the halothane gene in pig production programmes results in meat with an inferior quality and it can be recommended to exclude the halothane positive genotype from any pig production system where fresh pork quality is considered a primary goal.     

Pork quality from pigs fed on low glucosinate rapeseed meal: Influence of level in the diet,sex and ultimate pH

The appearance and eating quality of pork M. longissimus lumbrum from gilt and castrate pigs fed on diets containing a low glucosinate/low erucic acid rapeseed meal (cv. Tower) were assessed and compared with pork from pigs fed diets containing soya bean meal. At 90 kg liveweight, higher levels of either protein supplement, and therefore higher levels of dietary protein, gave slightly leaner meat. Meat from pigs fed rapeseed meal had more haem pigment and was slightly darker and redder than that from soya bean fed pigs. Differences in the quality of pork from the low glucosinate rapeseed meal and soya bean diets were small. Ratings for texture, juiciness and flavour of the lean varied little between the treatment groups. Suggestions that rapeseed meal as a protein supplement in diets might lead to inferior quality meat were not substantiated. The ultimate pH varied from 5.3 to 7.1 independently of the treatments and provided, for the first time, definitive relationships between pH and eating quality. Toughness and flavour were maximum and juiciness was a minimum after roasting meat of about pH 5.9. The ultimate pH had a larger effect on organoleptic quality than either sex or level of dietary inclusion of rapeseed or soya bean meals.     

Nutritional value of feed grade chickpeas for ruminants and pigs

The feeding value of feed grade chickpeas (Kabuli and Desi type) for ruminants and pigs was determined in two studies. Two ruminally fistulated cows were used in the first study to determine the effects of moist heat treatment (127 °C for 10 min) on the ruminal protein degradability of feed grade chickpeas. Heat treatment reduced (P < 0.05) soluble crude protein and increased (P < 0.05) the amount of crude protein associated with neutral detergent fibre for both types of chickpeas. Ruminal degradability of crude protein for Kabuli and Desi chickpeas was reduced by 39 and 33% (P < 0.05) respectively as a result of heating. In the second study, 64 crossbred pigs were each assigned to one of four dietary treatments in a factorial (4 treatments × 2 sexes) design experiment. The experimental barley/wheat‐based diets were supplemented with either soybean meal (control), Kabuli chickpeas (300 g kg⁻¹), Desi chickpeas (300 g kg⁻¹) or field peas (300 g kg⁻¹). Dry matter and gross energy digestibility coefficients, determined using the indicator method, were lower (P < 0.05) for the Desi‐ than for the Kabuli‐supplemented diet. However, no differences were observed in dry matter or gross energy digestibility between the Kabuli chickpea‐supplemented diet and the control or the field pea‐supplemented diet. Diets supplemented with chickpeas or field peas had a lower (P < 0.05) crude protein digestibility than the control diet. Pigs fed either of the chickpea‐supplemented diets during the growing phase gained less (P < 0.05) than pigs fed the control diet. However, during the finishing phase and over the entire experiment, dietary treatment had no effect on pig performance. There were no significant differences in carcass traits between pigs fed any of the four diets. It was concluded that moist heat treatment is an effective method to increase the rumen escape protein value of chickpeas and that the inclusion of feed grade Kabuli or Desi chickpeas in finishing diets up 300 g kg⁻¹ had no detrimental effects on pig performance. © 2000 Society of Chemical Industry     

SENSORY EVALUATION OF DRIED BEEF STRIPS TREATED WITH ACETIC ACID OR BRINE AND MONOSODIUM GLUTAMATE

Loss of characteristic meat flavor in dried beef, because of biochemical degradation of flavor-enhancing nucleotides, raises concern over the taste of meat products made in the home. Preservation effects on beef taste, using acetic acid and brine followed by dehydration were studied. Monosodium glutamate was added to the dried strips prior to cooking. The beefsteaks were subjected to three treatments: acetic acid, brine, while the control was untreated fresh beef. The samples were cut into strips then dried in a solar drier and an oven. Sensory attributes were evaluated for tenderness, juiciness, color, flavor and overall acceptability by an untrained sensory panel. Acetic acid, brine and control treatments were significantly different ( P <  0.05) from fresh beef in tenderness, juiciness and color. Cooked beef flavor comparisons indicated that brine was better ( P <  0.05) than acetic acid. Addition of monosodium glutamate to dried products significantly ( P <  0.05) improved cooked beef flavor and acceptability.

PRACTICAL APPLICATIONS

This is a low-cost method of meat preservation, and it is an appropriate technology that can be adopted in the arid and semi-arid areas of developing countries, because of its economic and nutritional implication. In these areas, meat production from small and large animals is the cornerstone of economic development and proper nutrition. These areas lack both refrigeration (the conventional method of meat preservation) and appropriate and affordable meat preservation technologies, making it impossible for the communities to utilize and market meat from their livestock profitably without sustaining high losses because of spoilage.     

A comparative study of boar taint in cooked and dry-cured meat

A comparative study of boar taint in cooked and dry-cured pig meat products was performed. Forty-eight cooked loins and 48 dry-cured hams from entire males and castrates were studied. The samples were classified according to the androstenone (AN) and skatole (SK) fat content determined using HPLC. A trained sensory panel evaluated taste, aroma, boar odour, boar flavour, juiciness, tenderness and fatness in cooked and dry-cured samples. Threshold levels of AN and SK to separate (P<0.05) entire and castrate samples according to their boar odour and flavour were determined. The effects of castration and processing on the eating quality were studied. Finally, the relationships among boar taint and other sensory attributes in cooked and dry-cured meat were compared. Results from these studies show that the eating quality of processed meat was affected negatively by boar taint. Threshold values were higher in dry-cured ham (2 μg g(-1) AN and 0.12 SK) than cooked loin (0.5 AN and 0.1 SK). AN and SK had a synergistic effect on boar odour and flavour in both products. AN had a greater influence than SK on the aroma and taste, especially in cooked meat. Boar odour was perceived more intensely than boar flavour in both of the products studied. Castration favoured fatness and improved the aroma and taste of cooked and dry-cured meat. The loss of aroma and taste due to boar taint was more noticeable in cooking than drying and curing. In dry-cured meat boar taint was associated with less aroma, taste, juiciness and tenderness. However, in cooked meat, boar taint affected the aroma and taste more strongly, but was not related with juiciness and tenderness, probably because these attributes are influenced by cooking.     

Influence of on-farm production practices on sensory and technological quality characteristics of pork loin

Quality of pork from pigs raised either traditionally (outdoor access or bedded settings with no sub-therapeutic antibiotics or growth promotants in feed) or conventionally (commercial indoor) was evaluated. Pork loins (m. longissimus thoracis et lumborum, LTL) from four hundred pigs from either traditional or conventional production systems (n = 200) fed commercially formulated diets ad libitum were harvested at slaughter. Intramuscular crude fat content and lean color (L* and b*) values were significantly decreased in conventional pork loins. LTL from conventionally-raised pig carcasses showed increased (P < 0.05) mean pH, moisture content and reduced cooking loss and shear force values and had increased tenderness and juiciness scores compared to those from traditionally-raised pig carcasses. Results indicated that pork from conventionally raised pigs was superior to that from traditionally raised pigs in terms of tenderness and juiciness, suggesting that consumers may value pork from traditionally raised pigs on the basis of factors other than eating quality and appearance.     

Synchronization of carbohydrate and protein sources on fermentation and passage rates in dairy cows.

Four ruminally cannulated Holstein cows in midlactation were randomly assigned to a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments to evaluate two nonstructural carbohydrate sources (corn or barley) with two sources of ruminally undegradable protein (soybean meal or extruded soybean meal) on milk production, ruminal fermentation, and digesta passage rates. Milk production (25.1, 27.5, 23.8, and 23.5 kg/d for the corn and soybean meal, corn and extruded soybean meal, barley and soybean meal, and barley and extruded soybean meal, respectively) and dry matter intake per unit of body weight (3.9, 4.1, 3.7, and 3.7%) were greater for cows fed corn than for cows fed barley and were similar for cows fed soybean meal or extruded soybean meal. Concentrations of ruminal NH3-N were greater for cows fed the corn and soybean meal diet than for cows fed other diets (15.0, 10.4, 9.0, and 11.3 mg/dl). Rumen volatile fatty acid concentrations were greater for cows fed corn than barley (133, 139, 121, and 118 mumol/ml). Fractional passage rates of solids from the rumen were greater for cows fed the barley and soybean meal diet than cows fed the corn and soybean meal diet (3.4, 3.9, 4.2, and 3.8%/h), and ruminal liquid dilution rates were similar for cows fed all diets (11.2, 11.0, 11.1, and 11.9%/h). The attempt to synchronize ruminal nonstructural carbohydrate and crude protein degradability produced minimal benefits for midlactation dairy cows.     

胍基乙酸对育肥猪肉品质和抗氧化能力的影响

本试验旨在研究日粮添加不同浓度胍基乙酸（GAA）对育肥猪生长性能、肉品质和抗氧化能力的影响。140头健康的体重相近的育肥猪,随机分为4个处理,分别饲喂在基础日粮中添加0（对照组）、300、500和700 mg/kg的GAA,饲养期为35天。饲养过程中记录体重和采食量,屠宰时采集背最长肌和血浆样品用于肉品质和抗氧化指标分析。日粮添加GAA对育肥猪日采食量、日增重均有提高的趋势,对料重比也有降低的趋势（P>0.05）,显著降低平均背膘厚（P<0.05）;添加GAA可以显著提高育肥猪背最长肌宰后45 min的pH值,降低滴水损失、蒸煮损失和剪切力值（P<0.05）,对肉色影响不显著（P>0.05）;添加GAA显著提高血浆中谷胱甘肽过氧化物酶活性和总抗氧化能力,降低丙二醛含量（P<0.05）;添加GAA显著提高背最长肌中超氧化物歧化酶活性和总抗氧化能力,降低丙二醛和羰基含量（P<0.05）。育肥猪日粮中添加GAA可以改善背最长肌肉品质,增强机体的抗氧化能力。     

凹凸棒石黏土对生长育肥猪生产性能、金属含量及肉品质的影响

研究凹土原土及热改性凹土对生长育肥猪生产性能、金属含量和肉品质的影响。选用体重约47kg健康"杜×长×大"三元杂交的生长育肥猪60头,随机分为3组,每组4个重复。对照组饲喂基础日粮,试验组饲喂在基础日粮中添加2%凹土原土、2%热改性凹土的试验日粮。结果表明:1)凹土原土和热改性凹土对生长育肥猪生产性能无显著影响(P0.05);2)凹土原土和热改性凹土降低血液中As、Pb、Cr含量和腿肌中Cr的含量(P0.05),热改性凹土显著提高血液中Mg含量(P0.05);3)凹土原土降低眼肌MDA(P0.05),凹土原土和热改性凹土降低眼肌中T-AOC的活性(P0.05);4)凹土原土提高眼肌p H45 min、a*45 min(P0.05),降低L*45 min、b*24 h和压力损失(P0.05)。添加凹土原土和热改性凹土能降低重金属在动物机体中的沉积、提高抗氧化能力进而改善肉品质,热改性凹土效果优于原土。     

Meat Palatability of Duroc and Chinese First-Cross Barrows

Duroc, Meishan, Fengjing and Minzhu boars were mated to White composite gilts. Trained sensory panel evaluation and Warner-Bratzler shear force determinations were made on chops that had been aged 4 days postmortem. No differences (P > 0.05) were found in juiciness, connective tissue amount, flavor intensity, tenderness or shear force values among sire breeds. No differences (P > 0.05) were detected in cooking losses, although meat from the Duroc-sired pigs cooked at a faster (P < 0.05) rate, but required longer cooking (P < 0.05) times than that from the other sire breeds. These data indicate the introduction of currently available Chinese genetics into the U.S. swine population would have little effect on the palatability of pork loin chops.     

Chickpeas as a substitute for corn and soybean meal in growing heifer diets

Twelve Holstein heifers (average weight 270 kg) were randomly assigned to one of four diets to evaluate the feeding value of chickpeas. Total mixed diets were composed of (dry matter) 40% concentrate mix, 24.5% chopped alfalfa hay, and 35.5% corn silage. Concentrate mixes contained 0, 25, 50, and 75% chickpeas in place of corn and soybean meal. Diets were fed individually for 80 d. Average daily gains (.98, 1.13, 1.14, and .95 kg) were higher for heifers fed 25 and 50% chickpeas than for those fed 0 and 75% chickpeas. Feed per gain (4.72, 4.05, 3.65, and 4.01 kg/kg) was lower for all diets containing chickpeas. Dry matter intake was lowest for heifers fed 75% chickpeas, and dry matter intake as percent of body weight was similar for all groups. Ruminal ammonia, pH, total volatile fatty acid concentrations, and ratio of acetate to propionate were similar for all diets. Serum urea and rumen parameters displayed no trends between diets. Chickpeas were an acceptable replacement for corn and soybean meal in growing heifer diets.     

AGING AND COOKING EFFECTS ON SENSORY TRAITS OF PORK FROM PIGS OF DIFFERENT BREED LINES

The effects of postmortem aging time (2, 9, and 16 days) and endpoint cooking temperature (60, 70, and 80C) on the eating characteristics of pork longissimus (LD) muscle were evaluated. Gilts (n=60) were from 4 different commercial hybrid genotypes (15 pigs/genotype) selected to produce a range of intramuscular fat. Results suggest that LD muscle from genotype 2, which was selected for its propensity to increase marbling had higher intramuscular fat content, tenderness and juiciness scores than that from the other genotypes (P < 0.05). Increasing aging time from 2 to 16 days increased sensory juiciness and tenderness, and decreased instrumental shear force and cooking loss (P < 0.05). Aging for nine days decreased shear force (P < 0.05) but had no effect on tenderness and juiciness scores and cooking loss when compared to 2 days aging. Increasing endpoint temperature increased cooking loss and shear force, and decreased tenderness (P < 0.05) and juiciness.     

Effects of quality grade on the chemical, physical and sensory characteristics of Hanwoo (Korean native cattle) beef

The effects of quality grade (which reflects relative marbling) on the chemical, physical and sensory properties was investigated using Korean native cattle (Hanwoo) beef. Thirty-six Hanwoo cows were slaughtered and the carcasses were graded at 24h postmortem according to the Korean carcass grading system. The quality grade 1 (high quality), grade 2 and grade 3 (low quality) were based on the marbling score of longissimus dorsi (LD) muscles. The effects of quality grade on the meat quality parameters of beef LD muscle were assessed during aging. Loin-eye area, fat thickness and yield grade were all similar for the three quality groups. Mean lean color, fat color and maturity scores did not differ among quality grade groups (P>0.05). pH, Sarcomere length, WHC, collagen content, cooking loss, shear force and MFI were not affected by quality grade groups. Drip loss for grade 1 group was significantly lower than that for grade 3 groups (P<0.05). At initial tenderness evaluation of steaks, no differences among the three grades were observed; however, with additional days of storage, grade 1 steaks had higher tenderness score than grade 3 steaks (P<0.05). Increased postmortem aging time improved tenderness attributes regardless of quality groups. No significant differences were found among the quality grade groups for flavor (P>0.05). The grade 1 group had the highest juiciness score, and grade 3 groups had the lowest score (P<0.05), but postmortem aging did not influence flavor and juiciness. The quality grades were more strongly related to juiciness than tenderness or flavor.     

CHARACTERISTICS OF PORK WITH DOCOSAHEXAENOIC ACID SUPPLEMENTED IN THE DIET

The omega-3 fatty acid, docosahexaenoic acid (DHA) was added to the basal diet of market pigs at 0, 0.125 and 0.250 kg/pig for 22–42 days. There were three consecutive pens per block with 10 blocks for a total of 30 pens assigned to each treatment group. No differences were found in off-flavor, juiciness, and overall flavor of the semimembranosus muscle and cured bacon among the three treatment groups. Furthermore, weight loss during storage and cooking did not differ among the three treatments. Objective evaluation results for oxidative rancidity did not differ between hams from control pigs and those from pigs receiving 0.250 kg/pig DHA. Shear force of cured bacon did not differ among the three treatments. These data suggest that DHA, when fed at 0.125 and 0.250 kg/pig, causes no adverse effects on carcass characteristics, sensory attributes, and tenderness of market size pigs.     

A RESEARCH NOTE CHEMICAL, PHYSICAL, AND SENSORY CHARACTERISTICS OF COLOR MODIFIED PORK RESTRUCTURED CHOPS

Restructured pork chops were manufactured from the lean tissue of dressed sows that were color modified(CM) with a potassium buffer rinse to attain lighter appearance. This product was compared with counterpart samples that were not color modified(C). Measurements included CIE L*, a*, b* values, visual traits, sensory traits, shear force, pH, and percentage of moisture, fat, protein, protein solubility, and cooking loss. The CM samples were lighter colored (P<0.05), exhibited less (P<0.05) flavor intensity, had a higher (P<0.05) pH, and sustained less (P<0.05) cooking loss. No differences (P>0.05) between the CM and C samples were found in juiciness, tenderness, Warner-Bratzler shear force, and soluble protein. The CM samples exhibited less protein content and lower Lee-Kramer shear force values. Results confirm that sow meat can be lightened without adversely affecting functional properties and taste attributes of restructured pork chops.     

饲粮双低菜粕水平对黄羽肉鸡生长性能、血液指标及肉品质的影响

本试验旨在研究饲粮双低菜粕水平对1~63日龄黄羽肉鸡生产性能、血液生化及肉品质的影响。试验选用1日龄快长型黄羽肉公鸡1 200只,随机分为5组,每组6个重复,每个重复40只鸡。处理Ⅰ-Ⅴ小鸡阶段双低菜粕添加水平为0%、2.5%、5%、7.5%、10%;中鸡阶段为0%、3%、6%、9%、12%;大鸡阶段为0%、7%、10.5%、14%、17.5%,试验期为63d。结果表明:与对照组相比,双低菜粕添加量为10%时可显著降低1~21日龄试鸡日增重,并提高饲料增重比(P0.05),各阶段双低菜粕添加量为5%、6%和10.5%时可显著降低63日龄试鸡体重(P0.05),当添加量达到10%、12%和17.5%时可显著提高1~63日龄试鸡饲料增重比(P0.05);各阶段饲粮双低菜粕添加量达到10%、12%和17.5%时显著降低了63日龄试鸡血浆游离T_3和游离T_4含量(P0.05),但各组间63日龄试鸡血浆谷草转氨酶、肌酸激酶、乳酸脱氢酶活性和肝脏谷胱甘肽硫转移酶活性均未见明显变化(P0.05),肝脏切片分析未见明显病变;各阶段添加10%、12%和17.5%的双低菜粕可显著降低63日龄试鸡屠宰后45 min的胸肉L*值,并提高a*值(P0.05),但对63日龄试鸡胸肉的感官风味及屠宰后96 h的pH、L*、a*、b*则无显著影响(P0.05)。试验结果提示,在快长型黄羽肉鸡饲粮小鸡阶段、中鸡阶段和大鸡阶段分别添加2.5%、3%和7%的双低菜粕(硫代葡萄糖甙含量为7.01μmol/g)未影响黄羽肉鸡的生长、甲状腺激素水平、机体抗氧化功能及肉品质。     

Effects of breed and marination on the sensory attributes of pork from Large White and Hampshire-sired pigs

The effects of breed and marination were tested for their effects on meat pH, water holding (marinade uptake and losses) and eating quality (tenderness, juiciness and flavour).

Loins were removed from one side of 20 Large White-sired and 20 Hampshire-sired pigs after slaughter, cut into four pieces and injected to 112% of their initial weight with water, a polyphosphate-containing marinade (pH 7.7) or a high pH marinade (pH 10.3). An uninjected piece of loin served as control. Samples were left overnight and then frozen before being thawed, cooked and assessed by a trained ten member sensory panel using 1–8 category scales.

Hampshires had higher intramuscular fat (0.95%) than Large Whites (0.62%) but otherwise the effects of breed were small compared with marination. Both marinades significantly increased meat pH from 5.5 (control) by 0.2 U, significantly reduced the cooking loss and increased the meat yield from about 80% to 90%. Water-injected samples lost large amounts of added water as drip after thawing and had a yield (76%) similar to the control. Marinaded samples retained more water post-cooking. Both marinades significantly increased tenderness (p < 0.001) and juiciness (p < 0.001) by about 1.0 U compared with the control (4.4 for tenderness and 4.2 for juiciness). Pork flavour, however, was significantly reduced (p < 0.001) and abnormal flavour was significantly increased (p < 0.001) by marination. Tenderness was positively correlated with pH after injection (0.83) and yield (0.75); juiciness was also positively correlated with pH after injection (0.78) and yield (0.87).

The absence of any significant difference in eating quality between control and water-injected samples, and the relatively large effects of marination, suggest that retained water (after cooking) is crucial in determining perceived tenderness and juiciness in pork.     

Conjugated linoleic acid content of milk and cheese from cows fed extruded oilseeds

Extruded oilseeds were fed to 24 dairy cows to study the influence on the conjugated linoleic acid content of milk and cheese. Cows were fed one of three diets that contained forage and grain in a ratio of 47:53. A control diet containing 13.5% soybean meal was compared with diets containing 12% full fat extruded soybeans or 12% full fat extruded cottonseed. The control, extruded soybean, and extruded cottonseed diets contained 2.73, 4.89, and 4.56% fatty acids, respectively. Measurements were made during the last 5 wk of the 8-wk experiment. The DM intakes and 3.5% fat-corrected milk yields were higher for cows fed the extruded soybean and extruded cottonseed diets than for cows fed the control diet. A tendency for lower fat and protein contents in the milk of cows fed the extruded soybean and extruded cottonseed diets was detected. Most of the C18 fatty acids were increased in the milk and cheese when extruded soybeans and cottonseeds were fed. The conjugated linoleic acid content in milk and cheese increased a mean of 109% when full fat extruded soybeans were fed and increased 77% when cottonseeds were fed compared with the conjugated linoleic acid content when the control diet was fed. Processing the milk into cheese did not alter the conjugated linoleic acid content. The conjugated linoleic acid content of milk and cheese can be increased by the inclusion of full fat extruded soybeans and full fat extruded cottonseeds in the diets of dairy cows.