胶原蛋白交联的研究进展及其对肉的纹理和嫩度的影响

胶原蛋白是肌间结缔组织的主要成分，它在股份中的含量和质量对肌肉纹理性状的影响实际上是取决于胶原蛋白分子之间交联的水平、方式和成熟程度。影响胶原蛋白分子之间产联的因素很多，包括动物的品种、年龄、性别和肌肉的来源以及其它一些与生长有关的环境因素。本文着重对由一系列酶介导的胶原蛋白分子间的共价交联。胶原蛋白在细胞外的被动修饰、胶原蛋白对烤制后肌肉纹理的影响、胶原蛋白分子之间交联及其影响因素和调控机制进行综述和探讨。     

肉嫩度及其影响因素的研究

近年来,人们对畜禽肉的品质要求越来越高,而嫩度作为肉品质的重要指标之一．已越来越引起人们的重视,结合国内外对肉嫩度的研究现状,系统的总结了影响猪肉嫩度的因素,同时对不同因素的影响机理及研究进展作了阐述,这将有助于我国肉类科学的发展。     

畜禽肉嫩度及其影响因素

嫩度是肉质性状的主要感官指标,通过现代育种手段培育肉嫩度较好的畜禽品种是目前育种工作的任务之一.论文综述了肉嫩度的物质基础,并从肌肉组成及屠宰后熟化过程的分析了影响嫩度的各种因素.     

鸡肉羟脯氨酸含量测定及其嫩度比较

肌肉由肌纤维、肌脂肪和结缔组织构成，羟脯氨酸是结缔组织中胶原蛋白的主要成分之一，其含量多少决定肌肉胶原蛋白的数量，与嫩度密切相关。由于畜禽年龄及各部位肌肉的结缔组织比例不同，其肉品的嫩度存在着明显差异。国外学者Cross(1973)和Crouse等较早对肉品中羟脯氨酸和胶原蛋白的含量进行了研究，我国自90年代后也分别开     

影响肉质嫩度的因素以及肉质嫩化方法的探讨

肉的嫩度是受很多因素影响的。本文结合国内外对肉质嫩度的研究现状,系统地总结了影响肉质嫩度的因素并对不同因素的研究进展作了阐述,同时对目前普遍使用的肉嫩化方法作了介绍。     

钙蛋白酶抑制蛋白与肉嫩度相关性

钙蛋白酶蛋白系统是影响肌肉生长和宰后肉嫩化的一个重要因素,主要由钙蛋白酶(μ-calpain和m-cal-pain)、钙蛋白酶抑制蛋白(calpastatin,CAST)及骨骼肌特异性钙蛋白酶(muscle specific calpain,P94)组成,钙蛋白酶抑制蛋白是一种内源性专一抑制钙蛋白酶(calpain)活性的蛋白,参与了调控肌原纤维蛋白的降解并在其中发挥了关键作用。本文概述了钙蛋白酶系统、钙蛋白酶抑制蛋白的结构、功能及其对提高肉嫩度的作用。     

牦牛肉嫩度的研究进展

牦牛肉是具有高蛋白、低脂肪和高能量的蛋白食物,因其受长期放牧饲养和屠宰的年龄较大等因素,牦牛肉的嫩度较差,其开发利用受到很大的限制。本文综述了肉的嫩度机理、牦牛肉嫩度的评价、影响牦牛肉嫩度的因素、人工嫩化技术以及其分子水平的研究进展,以促进牦牛肉的商品化及嫩化技术的应用。     

猪肉嫩度及其影响因素

嫩度是猪肉的主要食用品质之一,也是消费者评判猪肉质优劣最常用的指标.本文论述了猪肉嫩度形成的组织学原理及其评定方法,并从遗传与饲料营养的角度综述了影响猪肉嫩度的因素.     

影响肉品嫩度的因素及其候选基因的研究进展

肉品嫩度是评价肌肉食用品质的一项重要指标。同时,也是消费者评价肌肉质量高低的标准。结合国内外对肉品嫩度研究的现状,系统总结影响猪肉嫩度的因素,同时,着重对决定猪肉嫩度的候选基因及其致嫩机理加以综述。     

鸡肉嫩度评定方法及其指标间的相关分析

采用剪切值、胶原蛋白(总胶原蛋白、热溶性胶原蛋白、热残留胶原蛋白)和肌纤维结构(肌纤维密度、肌纤维直径)3种方法,分别评定了7个不同鸡种的嫩度。结果表明,应用3种评定方法可以划分出鸡种间的嫩度等级,但各指标间的嫩度排序有差异。相关分析表明,剪切值、总胶原蛋白、热残留胶原蛋白和肌纤维直径是嫩度评定的主要指标。其中剪切值与热残留胶原蛋白、热残留胶原蛋白与肌纤维直径和总胶原蛋白与热残留胶原蛋白为极显著正相关(P<0 01),剪切值与肌纤维直径为显著正相关(P<0 05)。经综合分析,剪切值的分辨率最高,热残留胶原蛋白、肌纤维直径综合代表性较强。以上评定结果与感官评定的嫩度对比有一定差异,感官评定与组织结构评定的结果相近,与剪切值、胶原蛋白两种方法差异较大。胸腿肌的嫩度不同方法存在差异,鸡种间比较建议采用胸肌为代表进行嫩度比较。     

Effects of pre-slaughter nutritional condition on intramuscular collagen solubility, pyridinoline cross-links and meat tenderness in aged goats

Effects of preslaughter nutritional condition on intramuscular collagen characteristics were studied, in order to clarify the potential of intensive feeding to aged animals in improving meat tenderness. Ten castrated male goats were assigned into one of two groups: one group was allowed ad libitum access to a concentrate diet (total digestible nutrients 70%, crude protein 15%) and Italian ryegrass hay (ADLIB‐group), and the other group was fed a restricted amount of their diet (concentrate diet 0.5% of bodyweight/day; hay 1.5% of bodyweight/day) to maintain their bodyweight (MAIN‐group). After 3 months of the experimental period, goats were slaughtered and meat samples were obtained immediately. Goats in ADLIB‐group had lower total and insoluble collagen concentrations, higher fat concentrations and collagen solubility than those in MAIN‐group, but soluble collagen concentrations of muscles were similar for both groups. Goats in ADLIB‐group had lower pyridinoline concentrations than those in MAIN‐group, in all muscles, but the differences of pyridinoline concentration between the groups were not statistically significant. Warner‐Bratzler shear force values of Longissimus and Biceps femoris muscles were lower in ADLIB‐group than in MAIN‐group. The increase of meat tenderness by preslaughter intensive feeding seemed to be associated with the increase in intramuscular fat deposition and high collagen solubility, and pyridinoline cross‐link appeared to be one of the factors related to collagen solubility.     

我国肉羊种业现状及发展建议

针对我国缺乏自主高产品种、品种资源利用缺乏有效指导导致肉羊单产能力低、羊肉品质差的肉羊种业现状,本文从地方品种保护和利用并重、本品种选育和引入品种相结合、坚持和完善品种登记制度等方面提出加强品种资源利用和管理对策,结合育种投入、育种规划、育种管理、育种技术4方面提出我国新品种培育工作建议,目的是加快推进我国肉羊种业科技创新,构建我国肉羊种业体系。     

水牛肉用资源开发与利用

水牛在我国农业与畜牧业的发展历程中占有重要的地位,随着农业机械化的发展,水牛的役用能力被替代。水牛具有耐粗饲、适应强、抗病力强等生理特点,其肉质中蛋白质高、脂肪低,对人类心血管等疾病预防有良好的作用。在我国牛肉市场供不应求的情况下,对水牛肉用资源的合理开发与利用显得尤为重要。本文对我国水牛资源现状、水牛肉用特点与优势等进行了概述,提出了水牛肉用资源开发利用的措施和建议。     

Health of finishing steers: effects on performance, carcass traits, and meat tenderness

The impact of respiratory disease during a 150-d feedlot finishing period on daily gain, carcass traits, and longissimus tenderness was measured using 204 steer calves. Feedlot health status was monitored in two ways. First, clinical signs of respiratory infection were evaluated each day; treatment with antibiotic was based on degree of fever (if rectal temperature exceeded 40 degrees C then calves were treated). Steers that were treated (n = 102) had lower (P<.05) final live weights, ADG, hot carcass weights (HCW), less external and internal fat, and more desirable yield grades. Steers that were treated had a higher prevalence of carcasses that graded U.S. Standard than steers that were never treated. Second, as an alternative index of health status, lungs of all steers were evaluated at the processing plant using a respiratory tract lesion classification system; this health index included presence or absence of preexisting pneumonic lesions in the anterioventral lobes plus activity of the bronchial lymph nodes (inactive vs active). Lung lesions were present in 33% of all lungs and were distributed almost equally between treated (37%) and untreated cattle (29%). Steers with lesions (n = 87) had lower (P<.05) daily gains, lighter HCW, less internal fat, and lower marbling scores than steers without lesions. Compared to steers with lesions but inactive bronchial lymph nodes (n = 78), steers with lung lesions plus active lymph nodes had lower (P<.01) ADG and dressing percentage. Longissimus shear force values for steaks aged 7 d were lower (P = .05) from steers without lung lesions than those for steaks from steers with lung lesions. Overall, morbidity suppressed daily gains and increased the percentage of U.S. Standard carcasses. Compared to health assessment by clinical appraisal (based on elevated body temperature), classification based on respiratory tract lesions at slaughter proved more reliable statistically and, thereby, more predictive of adverse effects of morbidity on production and meat tenderness.     

钙蛋白酶系统在肌肉生长和肉品嫩化方面的研究

钙蛋白酶系统主要由钙蛋白酶(calpain)及钙蛋白酶抑制蛋白(calpastatin)组成,calpain是存在于细胞质中的依赖于Ca2+的中性蛋白酶,calpastatin是钙蛋白酶的内源抑制蛋白。近年的研究表明,calpain是细胞质中主要的蛋白水解酶,在肌原纤维蛋白降解中起着重要的作用。肌肉增长和宰后嫩度的变化与蛋白质水解程度密切相关。因此,钙蛋白酶系统的活性会影响畜禽肌肉增长和肉的嫩度。文中综述了钙蛋白酶系统各种酶的结构及其如何在肌肉生长和肉的嫩化中起作用。     

Increased collagen III in culled chicken meat after feeding dietary wood charcoal and vinegar contributes to palatability and tenderness

We comprehensively evaluated meat quality in chickens fed a diet consisting of wood charcoal and vinegar (WCV) using food scientific and histological approaches. In culled hens, lipid and fatty acid in Musculus semimembranosus, cooking loss and sensory tests of whole thigh meat, and meat texture of breast meat were observed. In male broilers, cross section of M. semimembranosus was used for observations on muscle area, perimysium, non‐collagen total protein and total collagen content, and anti‐collagen I and III reactions. In frozen male broilers, conventional morphology of M. semimembranosus as well as chicken anti‐collagen III reaction to selected muscles of thigh meat and breast meat were compared between the control and WCV‐fed birds. Increased lipid and fatty acids, decreased cooking loss, high score in total evaluation for sensory test of thigh meat, and decreased meat texture values were observed for culled hens fed WCV. The higher values of muscle area, total collagen and collagen III were observed for broilers fed WCV. No perimysium collapse for M. semitendinosus or increased collagen III reactions of M. tensor fasciae latae, the flexor muscle group and M. pectoralis superficialis were observed for frozen muscles in the WCV group. These total results suggest that WCV produces palatable and tender meat by increasing collagen III.     

四种肉兔及杂交兔屠宰性能和肉品质的研究

对新西兰白兔、加利福尼亚兔、布列塔尼亚兔(A系)、齐卡兔(G系)、布列塔尼亚兔(A系,♂)×新西兰白兔(♀)、布列塔尼亚兔(A系,♂)×加利福尼亚兔(♀)、齐卡兔(G系,♂)×新西兰白兔(♀)、齐卡兔(G系,♂)×加利福尼亚兔(♀)100日龄屠宰性能和肉品质进行了研究.结果表明8个品种(组合)兔的屠宰率在52.76%～55.37%之间,其中加利福尼亚兔的屠宰率最高;肉骨比在4.65～6.53之间,以布列塔尼亚兔(A系,♂)×新西兰白兔(♀)肉骨比为最高;净肉率在82.25%～86.64%之间,亦是布列塔尼亚兔(A系,♂)×新西兰白兔(♀)净肉率最高.8个品种(组合)兔背最长肌pH值在6.33～6.88之间,差异不显著;背最长肌失水率在17.43%～20.26%之间,其中布列塔尼亚兔(A系,♂)×加利福尼亚兔(♀)失水率最低;腿肌的失水率在16.31%～18.00%之间,其中新西兰白兔失水率最低;8个品种(组合)兔腿肌的失水率比背最长肌的失水率要低;背最长肌的熟肉率在60.56%～66.81%之间,以布列塔尼亚兔(A系,♂)×新西兰白兔(♀)熟肉率为最高;腿肌的熟肉率在61.84%～66.54%之间,其中新西兰白兔熟肉率最高;背最长肌嫩度剪切值在2.18～3.96kg之间,其中加利福尼亚兔嫩度剪切值最低,嫩度最好;腿肌嫩度剪切值在2.59～3.64kg,其中新西兰白兔腿肌剪切值最低,嫩度最好.     

肉骨粉类饲料在畜牧业上的应用与研究

肉骨粉类饲料营养价值较高,营养成分的变异性很大,其养分的利用率属于中等水平,存在一定的安全性问题。本文就肉骨粉类饲料的营养特点、饲用安全性和肉骨粉的可利用性及其在畜牧业上的应用作一简要综述。     

Effects of growth implants on consumer perceptions of meat tenderness in beef steers

Anabolic steroid implants are routinely used to increase growth performance and profitability; however, there are concerns that the use of implants, particularly those containing trenbolone acetate, may have detrimental effects on carcass quality and beef tenderness. Thus, the objectives of the current study were to determine the effects of various commonly used implant regimens on shear force values, sensory properties, and consumer satisfaction of beef top loin steaks from cattle of Bos indicus influence. Cattle were supplied by producers that agreed to provide sire and dam information in exchange for carcass and sensory data. Steers (n = 2,748) were assigned randomly to one of three implant treatments (12/sire; four steers from each sire were placed into each treatment group): 1) unimplanted controls (n = 1,368); 2) Synovex-S followed by another Synovex-S (n = 660); or 3) Synovex-S followed by Revalor-S (n = 720). Steaks sampled after 3, 7, and 14 d of aging indicated that unimplanted cattle had lower (P < 0.05) Warner-Bratzler Shear force values than those from implanted animals. No differences (P > 0.05) in shear force values were found between the two treatments or the control groups for steaks sampled following a 21-d aging period. Steaks from implanted animals sampled after 3, 7, and 14 d aging were rated lower (P < 0.05) for initial and sustained trained sensory panel tenderness scores. Consumers failed to detect any differences in steak samples related to implant treatment after 7 and 14 d of aging. Consumer education level and family income did not affect overall acceptability (P > 0.10 and 0.18, respectively) or tenderness acceptability (P > 0.11 and 0.68, respectively); however, consumers with postgraduate degrees recorded lower (P < 0.05) overall quality, beef flavor, juiciness, and tenderness scores than consumers in all other education classifications. Additionally, family income had no effect on overall quality (P > 0.21), beef flavor (P > 0.28), juiciness (P > 0.58), or tenderness (P > 0.45) scores. Results indicate that using a moderate implant program in Bos indicus-influenced cattle has no detrimental effects on beef tenderness and consumer acceptability.     

小麦型日粮中添加木聚糖酶对肉鸭生产性能的影响

本试验在小麦型基础日粮中分别添加木聚糖酶0、50、100、150、200g/t饲料(5000U/g酶)饲喂12日龄樱桃谷肉鸭,观察木聚糖酶对肉鸭生产性能的影响。结果表明:添加木聚糖酶对肉鸭生产性能影响不显著(P0.05),单位增重饲料成本以添加量50 g/t(即每1 kg饲料含250 U木聚糖酶)的有效含量为佳。