Comparison of different pH measurement methods in meat

The accuracy of portable pH meters and the nitrazine yellow method was compared with the reference method by determining the pH of 74 beef and 96 pork muscles. The pH was measured directly from the muscle. The results showed statistically significant differences (p less than 0.001) between the different electrometric combinations. Combinations of portable pH meters with puncture electrodes gave systematically higher pH values than the reference method. These differences were not very large but they may be of practical significance. The use of a piercing cover on the electrode to help the insertion of the electrode into the meat is not recommended, since it may cause a rise in pH values. Electrometric methods were found to be more precise than the nitrazine yellow method. On the basis of these findings there still is a need of further harmonization of the methods used for pH measurement of meat.     

肉用西门塔尔牛与和牛杂交群体的肉品质分析

本研究旨在对肉用西门塔尔牛与杂交和牛两试验群体进行肉质性状比较,以期为肉品质性状遗传机制剖析及优质肉牛培育提供理论指导。收集肉用西门塔尔牛与杂交和牛两试验群体肉质性状表型数据,包括眼肌面积、剪切力、系水力、pH、肉色、脂肪颜色和大理石花纹等指标,进行相关性及差异性分析,从而综合评价两群体的肉品质。结果显示,两群体的脂肪颜色、系水力及剪切力呈现两两正相关;肉色与脂肪颜色、pH呈正相关,且肉色与pH呈显著相关（P < 0.05）,而系水力与pH、肉色和大理石花纹呈负相关。在两试验群体间,和牛杂交群体的大理石花纹、眼肌面积、pH性状表现为极显著优于肉用西门塔尔牛（P < 0.01）。从性别比较来看,肉用西门塔尔牛母牛在大理石花纹、pH、剪切力等性状上极显著或显著优于公牛（P < 0.01;P < 0.05）;而和牛杂交群体母牛的肉色和剪切力性状表现为显著或极显著高于公牛（P < 0.05;P < 0.01）。总体而言,和牛杂交群体的肉质性能优于肉用西门塔尔牛;群体内比较表明,肉用西门塔尔牛群体母牛肉质性能优于公牛,而和牛杂交群体母牛肉质性能低于公牛。     

维生素D_3对家畜肉质的影响

近年的研究发现,补饲维生素D3能够提高牛肉的嫩度,还能改善猪肉的色泽。本文阐述了维生素D3对家畜肉质的影响及研究现状,并对维生素D3改善家畜肉质的作用途径进行了分析。     

Comparative Study on Carcass Traits and Meat Quality of Different Month Old of Xinjiang Brown Cattle Steers

In this research,12 heads of 28 to 30 months (low months age group) and 8 heads of 32 to 34 months (high months age group) Xinjiang Brown cattle steers which fed in the same mode of nutrition were chose for the slaughter test,in which the carcass traits,nutrient composition and some edible quality index were measured and comparative analyzed,a research which through comparative analysis the carcass traits and meat quality of nutritional components of different months of Xinjiang Brown cattle steers was carried out.The results indicated that the marbling,carcass grade,fat,meat color of high months age group were better than that of low months age group,the traits of the low months age group on fat color,moisture,protein,cooking loss and shear force value were better than that of high months age group,and there were significant difference on the traits of fat and meat color L^* between the two groups (P<0.05),while the differences of other traits between them were not significant (P>0.05);As high-grade beef,in addition to the traits of meat color and pH value of the chunk roll,tenderloin and striploin,each site of the meat traits on the fat,protein,moisture,cooking loss,shear force value indicators were all better than other parts,and showed the best of nutritional value and edible quality.28 to 34 months of Xinjiang Brown cattle steers could produce high-grade beef,the meat could be used as the raw materials of steak and boiled beef.     

不同月龄新疆褐牛阉牛胴体性状及肉品质比较研究

选择相同营养模式下低月龄组(28~30月龄)12头、高月龄组(32~34月龄)8头新疆褐牛阉牛进行屠宰,分别对胴体性状、营养成分、部分食用品质指标进行测定和比较分析,旨在探索新疆褐牛阉牛生产高档牛肉的适宜月龄。结果表明,高月龄组大理石花纹、胴体等级、脂肪、肉色均优于低月龄组,低月龄组脂肪色泽、水分、蛋白质、蒸煮损失、剪切力值优于高月龄组,且脂肪、肉色L^*值差异显著(P<0.05),其余组间差异均不显著(P>0.05);上脑、里脊、外脊作为高档牛肉,除肉色、pH外,脂肪、蛋白质、水分、蒸煮损失、剪切力值指标均优于其他部位,表现出了极好的营养价值和食用品质。28~34月龄阶段的新疆褐牛阉牛可以生产高档牛肉,其肉品都可作为牛排和涮牛肉的原材料。     

Back-fat thickness as a primary index reflecting the yield and overall acceptance of pork meat

Predicting aspects of lean meat yield and eating quality of pork based on some particular carcass traits become increasingly important from an economic profitability point of view. The present study aimed to determine the relationship between the back-fat (BF) thickness with lean meat yield and meat quality traits of crossbred pigs. A total of 220 crossbred pigs [(Landrace × Yorkshire) ♀ × Duroc ♂] reared under identical conditions and harvested at 180 days old were slaughtered and screened for BF thickness. Four BF thickness groups: 12–15, 16–20, 21–25, and 26–30 mm were classified, and longissimus dorsi (LD) muscles from these groups were used to analyze meat quality characteristics. Results showed that increasing BF thickness decreased the lean meat yield and loin lean area. Increasing BF thickness up to 26–30 mm increased intramuscular fat content and pH of LD muscles. The LD muscles of the thicker BF (21–30 mm) groups received significantly higher flavor, juiciness, and overall acceptability scores than those of the thinner back-fat (12–20 mm) groups. Overall, when all the pre-harvest factors are kept the same, BF thickness could be considered as a primary index for predicting lean meat yield, and the minimal back-fat thickness of 21–30 mm is required to improve the overall acceptability of pork meat.     

生物饲料对不同品种肉牛肉质的影响分析

牛肉具有高蛋白质,低脂肪,含磷脂多、胆固醇少,肌肉纤维细嫩、柔软,风味独特等优点。随着人们生活水平的提高和膳食结构的改变,牛肉消费量也持续增加,为牛肉生产带来了难得的发展机遇。试验研究相同饲养管理条件下,生物饲料对不同品种肉牛肉中屠宰性能和常规营养成分的影响,证明安格斯公牛在胴体重、屠宰率、净肉重、净肉率和胴体产肉率相比西杂牛更高(P<0.05);而水分、粗脂肪、粗蛋白含量也存在较大差异(P<0.05)。这能够为提高肉牛的肉质提供科学的依据,在肉牛生产中具有重要的实践指导意义。     

饲喂微生物发酵小麦秸秆对肉牛生长性能和屠宰性能的影响

为研究微生物发酵小麦秸秆对肉牛生长性能和屠宰性能的影响,试验采用单因素设计,选择体重相近的健康肉牛120头,随机分成4组,每组3个重复,每个重复10头,试验1、2、3、4组分别饲喂微生物发酵小麦秸秆替代0%、20%、40%、60%普通小麦秸秆的基础日粮,试验期为60 d,在试验结束时测定生长性能和肉品质。结果表明:(1)试验3、4组料重比较1组分别降低6.74%、5.87%(P<0.05);试验2、3、4组的平均日采食量均高于1组(P>0.05);试验3、4组的日增重较1组分别提高36.6%、24.4%(P<0.05);试验2、3、4组熟肉率、失水率、肉色、嫩度与1组均差异性不显著(P>0.05);试验2、3、4组的粗灰分、p H均低于1组(P>0.05);试验3、4组粗蛋白质、粗脂肪、大理花纹分别较1组提高19.28%、18.94%、45.15%、42.35%、46.75%、43.09%(P<0.05)。综上所述,饲喂微生物发酵小麦秸秆替代40%普通小麦秸秆日粮可以提高肉牛的生长性能和肉品质。     

Search for an index for the taste of Japanese Black cattle beef by panel testing and chemical composition analysis

To search for an index for chemical composition related to superior taste in Japanese Black beef, we conducted panel tests and analyzed the chemical composition of seven beef brands. Thirty‐five sirloin beefs from five heifers were used in this study, sold under seven beef brands graded as more than A4 on the Japanese Meat Grade scale. The chemical composition analyses assessed both raw and roasted meat, the latter of which was roasted under the same conditions as those used for the panel test. Results of the panel test and chemical composition analyses revealed that fatty acid composition, sugar content, adenosine triphosphage (ATP)‐related compounds, amino acid composition and odor composition in the sirloin meat differed among beef brands. Furthermore, the correlations of chemical compositions between roasted and raw meat were significantly high. Sugar content and ATP‐related compounds in roasted meat were significantly correlated with the item ‘overall evaluation’ of the panel test. ATP‐related compounds, such as inosinic acid, carnosine and taurine, in roasted and raw meat were correlated significantly with the item ‘umami intensity’ of the panel test. These results suggest that the composition of these components is important for an index related to the overall evaluation of beef.     

用双抗夹心ELISA鉴别不同肉类的研究

以辣根过氧化物酶标记兔抗不同动物肌肉和血清球蛋白抗血清检查860份牛肉、510份马肉、510份猪肉、310份羊肉和100份驼肉,检出率均在95％以上;经与其它血清学方法比较,证实用该法鉴别不同肉类,具有较高的敏感性和特异性,而且方法简便,设备简单,判断指标客观真实,经研制配套的商品化诊断盒,可供肉品检疫部门及有关单位野外应用。     

羧化胶乳凝集抑制试验快速鉴别牛肉和马肉的研究

以羧化聚苯乙烯胶乳作为载体,将牛血清和马血清分别共价交联到载体微球的表面,制成免疫微球.将此免疫微球同相应的抗血清配对,进行胶乳凝集抑制试验以鉴别牛肉和马肉.通过对265头份牛肉、242头份马肉、100头份猪肉、60头份羊肉、30头份狗肉、13头份骡肉和4头份驴肉鉴别,牛肉胶乳试剂和马肉胶乳试剂的敏感性均为100%,牛肉胶乳试剂的特异性为100%,马肉胶乳试剂同骡肉和驴肉呈完全交叉反应.实验具有良好的重复性和稳定性,试剂易于保存,本试验可在5min内报告结果,操作简便,适于基层动检部门应用.     

不同饲料添加剂对肉牛生长发育与产肉性能影响的研究

试验旨在研究两种添加剂在相同配方下对肉牛各组织器官生长发育的影响。选择健康的新疆周岁褐牛公牛30头,随机分为3组,试验组与对照组日粮相同,试验Ⅰ组精料中添加1%的肉牛育肥饲料复合添加剂,试验Ⅱ组精料中添加0.2%的巴尔吡尔。对肉牛骨骼与脏器组织生长发育、产肉性能进行测定与分析。结果表明,与对照组相比,试验Ⅰ、Ⅱ组在腰角宽、髋宽上差异显著(P<0.05),另外,能显著增加试验Ⅱ和试验Ⅰ组的血液与复胃的重量(P<0.05);具有增加胴体重与高档、优质肉产量,提高屠宰率,调控不同部位肌肉组织生长的效果。与对照组相比,试验Ⅰ、Ⅱ组在育肥增重、胴体、净肉、高档优质肉销售收益上获利增加额分别为42.7、130.6、142.22、141.6和-15.8、38.2、76.1、149.7元。因此,两种添加剂对动物的生长发育、肌肉、骨骼、脂肪组织具有一定的调控作用,巴尔吡尔添加剂具有增加肉牛脂肪代谢,降低体脂的功效,可作为安全、高效饲料添加剂应用于肉牛育肥生产中。     

The effect of high pre‐slaughter environmental temperature on meat quality traits of Italian autochthonous pig Suino Nero Lucano

The aim of the present study was to evaluate the effect of high pre‐slaughter environmental temperature on meat (Longissimus lumborum muscle) quality traits of Italian autochthonous pigs Suino Nero Lucano (SNL). High pre‐slaughter environmental temperature influenced the meat quality of autochthonous pigs. In particular, the meat from SNL pigs exposed to heat stress (H) showed significantly lower pH values at 24 and 48 hr post mortem, haem iron content and redness (a*) value, and a significantly higher shear force, drip loss and lightness (L*) values, compared to meat from SNL pigs reared under comfortable environmental temperature (C). Moreover, H meat showed a significant reduction of vitamin A, vitamin E, creatine and carnosine content, compared to C meat. Despite this, no pale‐soft‐exudative pork was found in our study, and no significant difference was detected between two studied groups for intramuscular fat and protein content of meat. In addition, despite the meat from SNL pigs exposed to heat stress has suffered a qualitative decrease, it showed a good endogenous antioxidants content.     

日粮中添加沼渣对猪肌内脂肪酸组成及含量的影响研究

试验选择18头杜×长×大三元杂交猪为试验材料，研究了日粮中添加沼渣对猪肌内脂肪酸组成及含量的影响。结果显示，除背最长肌中油酸含量有显著差异外，其余脂肪酸的含量无显著差异。通过分析认为，日粮中添加沼渣不会从肌内脂肪酸组成及含量上对猪肉风味及其他肉质性状产生不利影响，但需要注意日粮中添加过高比例的沼渣可使猪肉中多不饱和脂肪酸增多，有导致肉品质变差的倾向。     

兰州市肉与肉制品微生物污染状况的研究

目的：了解兰州市定点屠宰场生猪屠宰加工产品的卫生质量以及肉与肉制品致病菌污染状况。方法：2003-2006年,应用国标法对2个定点生猪屠宰场300份生猪胴体样品进行了菌落总数、大肠菌群和沙门氏菌检验;采用随机采样法对兰州市不同酒店和超市的生猪肉、牛肉、羊肉、禽肉100份,熟肉制品1 200份进行了常见致病菌的检验。结果：生猪胴体体表和肉样沙门氏菌检出率分别为7.5%和14%;生肉检出致病菌阳性20份,总检出率为20%;熟肉制品检出致病菌阳性39份,阳性率为3.25%。生肉中以猪肉致病菌阳性率最高,为20%。结论：兰州市生猪胴体的卫生质量急需提高,屠宰生产加工水平亟待改善。     

不同饲养方式对江城牛肉品质的影响

试验旨在研究不同饲养方式对江城牛肉品质的影响,获得江城牛最优肉品质的饲养方式。选取年龄在2.5岁左右、健康状况良好的24头江城牛,其中公牛9头、母牛15头,根据性别随机分成3组,每组8头（公牛3头、母牛5头）,第1、2组舍饲,在自由采食全株玉米青贮的基础上,每头牛每天分别补饲肉牛精料补充料2 kg（精料补充料组）和浓缩料1 kg（浓缩料组）,第3组在人工草地上放牧饲养（放牧组）,饲养90 d后从精料补充料组和浓缩料组分别选4头,从放牧组选6头,公母各半,共14头进行屠宰试验,测定江城牛的肉品质。结果表明,不同饲养方式对江城牛肉品质有一定影响,补饲精料补充料和浓缩料后,江城牛在失水率、剪切力、粗脂肪、粗蛋白质方面与放牧组存在显著差异（P<0.05）,其他成分各组间差异均不显著（P>0.05）,但眼肌面积、背膘厚度、大理石花纹等表现为补饲了精料补充料和浓缩料的牛肉品质优于放牧组。不同饲养方式对江城牛肉品质有一定的影响,补充精料补充料和浓缩料后,在肉品质方面,精料补充料组和浓缩料组优于放牧组。说明在饲养过程中可以通过补充精料补充料和浓缩料改善江城牛的肉品质。本研究结果为江城牛的合理饲养和提高肉品质提供了理论依据。     

Effects of feeds on flavor of red meat: a review

The effects of diet ingredients on red meat flavor are dependent on the type of diet, and, to a large extent, on the species: pork, mutton or lamb and beef. Sensory analysis of meat flavor has been used in most of the studies on the effects of feeds on meat flavor. In general, high-energy grain diets produced a more acceptable or a more intense flavor in red meats than low-energy forage or grass diets. Feeding pigs unsaturated fats increases the unsaturation in pork fat but results in only minor changes in pork flavor. Sheep must be fed protected, unsaturated fats in order to increase the unsaturation in their fat to be similar to pork fat. This increased unsaturation results in a greater flavor change in lamb or beef than in pork. Several dietary ingredients such as fish products, raw soybeans, canola oil and meal, and pasture grasses cause undesirable flavors in red meat. Analyses of lamb and beef produced on different diets have shown that type of feed affects the concentration of many flavor volatile compounds. However, only a few studies have quantified the volatiles of beef and lamb produced on different diets, and no reports of studies were found in which the volatiles of pork produced on different diets had been investigated. Hence, the importance of these changes in volatile concentration to meat flavor has not been determined.     

International red meat trade.

The maturation of the US beef and pork markets and increasing consumer demands for convenience, safety, and nutrition suggests that the beef and pork industries must focus on product development and promotion. New marketing arrangements are developing that help coordinate production with consumer demands. The relative high levels of incomes in the United States are likely to increase the demands for branded products rather than increase total per capita consumption. Foreign markets represent the greatest opportunity for increased demand for commodity beef and pork products. Increasing incomes in developing countries will likely allow consumers to increase consumption of animal-source proteins. Real prices of beef and pork have declined substantially because of sagging domestic demand and increasing farm-level production technologies. Increasing US beef and pork exports have obviated some of the price declines. Pork attained a net export position from a quantity perspective in 1995. The United States continues to be a net importer of beef on a quantity basis but is close to becoming a net exporter in terms of value. By-products continue to play a critical role in determining the red meat trade balance and producer prices. The United States, however, must continue to become cost, price, and quality competitive with other suppliers and must secure additional market access if it is to sustain recent trade trends. Several trade tensions remain in the red meat industry. For example, mandated COOL will undoubtedly have domestic and international effects on the beef and pork sectors. Domestically, uncertainty regarding consumer demand responses or quality perceptions regarding product origin, as well as added processor-retailer costs will be nontrivial. How these factors balance out in terms of benefits versus costs to the industry is uncertain. From an international perspective, some beef and pork export suppliers to the United States could view required labeling as a trade restriction, which could ultimately impact future US red meat exports. Conversely, some countries may view such labeling requirements as an opportunity to brand high-quality products. The US lamb meat industry has experienced declining real prices, domestic production, and demand. The cessation of wool incentive payments, increased environmental regulations, and competition by imports have significantly affected the industry. Import suppliers have capitalized on product quality in this niche market. Trade restrictions initially imposed in 1999 by the US Government were ruled illegal by the WTO. The US Government responded by providing financial assistance to lamb producers. Product quality improvements and promotion aimed at the domestic market, however, will be critical factors in shaping the economic viability of the US lamb meat industry.     

Changes in the quality of meat (Longissimus thoracis et lumborum) from Kamieniec lambs during long‐term freezer storage

The aim of this study was to determine changes in the quality of lamb meat (Longissimus thoracis et lumborum), which was vacuum‐packaged and freezer‐stored (?26°C) for 6 and 12 months. The experiment was performed on 12 male lambs of the Kamieniec Longwool breed, raised to 106 days of age. In comparison with fresh meat, thawed meat was characterized by lower ash content, higher pH, greater natural drip loss and cooking loss, and lower scores for taste intensity. Vacuum packaging and low‐temperature storage protected lamb meat against oxidative changes, and alleviated the adverse effects of oxidation on the color, aroma and taste of meat. It can be concluded that freezer storage (?26°C) of vacuum‐packaged meat can help meet consumer demand for lamb meat products in periods when fresh meat is unavailable. However, it should be noted that long‐term frozen storage induces undesirable changes in meat quality, including a decrease in water‐holding capacity and taste intensity.     

去势对西门塔尔牛牛肉品质的影响

为分析去势对17~21月龄西门塔尔牛牛肉品质的影响,本研究选取50头健康的、16月龄的西门塔尔公牛,进行药物驱虫后,依据体重进行配对试验设计,设置去势组和未去势组,每组25头,同一阶段饲喂相同饲粮,试验期150d。结果表明,与未去势组相比,去势极显著提高了牛肉的肌红蛋白含量(P0.01),极显著降低了背最长肌的pH(P0.01),显著提高了牛肉的大理石花纹、脂肪、干物质、油酸和单不饱和脂肪酸含量和MUFA/SFA、MUFA/PUFA比值(P≤0.05);去势具有降低牛肉硬脂酸含量的趋势(0.05P≤0.10)。上述结果说明:去势能提高17~21月龄西门塔尔牛牛肉的大理石花纹等级,改善牛肉的色泽,增加牛肉脂肪和干物质含量,提高牛肉中油酸和单不饱和脂肪酸的含量。在生产中,在1.5岁左右对西门塔尔公牛去势,可达到改善牛肉品质的目的。