鸡肉风味候选基因AMPD1、ADSL、ATIC 的分析

对优质肉鸡肉品质利用候选基因遗传标记在基因水平上进行研究,找到对优质鸡肉品质性状有较大影响的几个基因,获得更符合市场需要,更能满足人们对鸡肉品质需求的优质肉鸡,是当前禽育种工作亟待解决的问题。肌苷酸是鸡肉质鲜味特性的主要物质基础,感官试验结果表明,肌苷酸的鲜味呈味作用显著,肉品IMP含量的差异会对肉品总体风味产生一定作用,作用大小与肌苷酸和谷氨酸钠等其它风味物的协同作用有关,因此影响肌苷酸生成的各种基因都是潜在的候选基因。腺苷一磷酸脱氨酶（AMPD1）、腺苷酸琥珀酸裂解酶（ADSL）、次黄嘌呤核苷酸环水解酶（ATIC）等3种酶是产生肌苷酸过程中3个重要的酶。作者对以上3种酶进行了分析和论述,以期为分子育种提供参考。     

育肥方式对滇南小耳猪肌肉氨基酸的影响

为探讨育肥方式对滇南小耳猪肌肉风味氨基酸的影响以生产优质猪肉,模拟产区规模养殖场(对照组)、"吊架子"(试验Ⅰ组)和"放养+补饲"(试验Ⅱ组)3种方式进行育肥试验,屠宰并测定其肌肉氨基酸含量,比较呈味氨基酸含量及味道强度值。结果显示:试验Ⅰ组和Ⅱ组肌肉的鲜味、甜味氨基酸总量分别比对照组提高11.65%、10.56%(P0.05)和14.52%、14.12%(P0.05),鲜味、甜味、酸味强度值分别比对照组提高11.85%、11.35%、12.82%(P0.05)和14.76%、14.57%、15.46%(P0.05)。滇南小耳猪肌肉中鲜味、酸味贡献最大氨基酸是谷氨酸,甜味、苦味贡献最大的是组氨酸。"吊架子"和"放养+补饲"2种育肥方式可提高滇南小耳猪肌肉呈味氨基酸含量和呈味强度,显著增强丙氨酸的鲜味及甜味味道强度值。     

武定鸡和大围山微型鸡肌苷酸含量与PURH基因表达差异研究

肌苷酸(Inosinic acid,IMP)是影响畜禽肌肉鲜味的主要成分,对肉品质风味有重要影响。为探究IMP含量与次黄嘌呤核苷酸环水解酶(PURH)基因表达量的关系,试验以武定鸡和大围山微型鸡为研究对象,在相同饲养条件下,于90、120、150日龄进行屠宰(公母各半),分别测定肌肉组织中IMP含量以及PURH mRNA表达量,并进行相关性分析。结果显示:随着日龄的增长,武定鸡和大围山微型鸡肌肉中IMP含量显著上升(P0.05),武定鸡肌肉中IMP含量显著高于大围山微型鸡(P0.05);武定鸡和大围山微型鸡母鸡肌肉中IMP含量均高于公鸡,胸肌中IMP含量均高于腿肌;武定鸡和大围山微型鸡肌肉中不同日龄PURH mRNA表达水平存在显著差异(P0.05),总体呈先升高后降低趋势,且PURH mRNA表达水平与IMP含量呈正相关。本试验结果表明:相同饲养条件下武定鸡肉品质优于大围山微型鸡,且PURH基因对肌苷酸的合成起关键作用。     

家禽肌肉肌苷酸含量影响因素的研究进展

肌苷酸具有显著鲜味呈味作用,是影响肉质风味的重要物质基础。本文综述了家禽肌苷酸的形成机理、代谢途径和影响因素的研究进展,以期为动物营养工作者在肉质风味方面的研究提供借鉴与参考。     

不同枣粉水平对陕北白绒山羊肉呈味物质的影响

本试验旨在研究不同枣粉水平对陕北白绒山羊肉呈味物质的影响。选取40只6月龄、初始体重为(20.15±1.63)kg的健康陕北白绒山羊,随机分为5组(每组8个重复,每个重复1只羊),分别饲喂含0(对照组)、10%(试验Ⅰ组)、15%(试验Ⅱ组)、20%(试验Ⅲ组)、25%(试验Ⅳ组)枣粉的试验饲粮。预试期10 d,正试期70 d。结果显示:1)试验Ⅲ组的鲜味值显著高于对照组及试验Ⅱ和Ⅳ组(P<0.05),咸味值显著高于对照组(P<0.05)。2)试验Ⅲ组的天冬氨酸(Asp)和丙氨酸(Ala)含量显著高于对照组(P<0.05),谷氨酸(Glu)含量显著高于对照组及试验Ⅰ和Ⅱ组(P<0.05)。3)随着枣粉水平的提高,肌苷酸(IMP)、肌苷(INO)和次黄嘌呤(HYP)含量逐渐增加,一磷酸腺苷(AMP)含量先增加后降低,试验Ⅱ、Ⅲ和Ⅳ组的IMP含量显著高于对照组和试验Ⅰ组(P<0.05),试验Ⅰ、Ⅱ、Ⅲ和Ⅳ组的INO、HYP和AMP含量显著高于对照组(P<0.05)。由此得出,枣粉能促进氨基酸和呈味核苷酸在陕北白绒山羊肉中的积累,饲粮中枣粉水平为20%时,羊肉中呈鲜味的游离氨基酸和核苷酸含量较高,滋味最好。     

北京油鸡不同组合杂交性能的研究

采用北京油鸡(YY)与矮脚黄鸡(DD)、石歧黄鸡(CC)分别进行正反杂交,观测亲本及其杂交组合的生长性能、胴体性状、肌苷酸(IMP)和肌内脂肪(IMF)等肉品风味性状,比较各性状的杂种优势,为培育优质北京油鸡配套系提供理论依据。结果表明,YY与DD杂交组合(YD)的增重、料肉比及产肉量杂种优势明显,胸肉IMP和IMF含量未降低。因此YD组合既能保持商品代鸡肉较高的IMP和IMF含量,同时能节省父母代养殖成本,并有效防止种源的流失。     

巨型玫瑰冠鸡ADSL基因表达及其与IMP的相关分析

为探讨腺苷琥珀酸裂解酶(ADSL)基因在巨型玫瑰冠鸡胸肌与腿肌中的表达以及与肌苷酸(IMP)的关系,研究ADSL基因对巨型玫瑰冠鸡肌肉中鲜味物质的影响作用。本试验采集巨型玫瑰冠鸡与良凤花鸡在不同周龄(2、4、6、8、10、12周龄)的胸肌、腿肌组织样品共96份,采用实时荧光定量PCR方法对巨型玫瑰冠鸡与良凤花鸡不同生长阶段组织中ADSL基因表达量进行检测,并采用高效液相色谱法测定了两种鸡12周龄的胸肌与腿肌的IMP含量。结果表明:巨型玫瑰冠鸡与良凤花鸡的胸肌中ADSL基因表达的变化趋势基本一致,2周龄、4周龄时巨型玫瑰冠鸡的表达量远高于良凤花鸡(P0.01),10周龄时两品种间表达量呈差异显著水平(P0.05);两品种鸡腿肌中ADSL基因的表达均呈波动性变化,且都在8周龄时最低、10周龄时最高;ADSL基因表达量与肌肉中的IMP含量显著正相关。因此,可将ADSL基因作为巨型玫瑰冠鸡肌肉中鲜味物质性状选育的候选基因。     

鸡肌肉肌苷酸合成代谢相关基因研究进展

肌苷酸是影响肉质风味的重要物质基础,其鲜味呈味作用显著,因此影响肌苷酸生成的各种基因都是潜在的候选基因。腺苷琥珀酸裂解酶(ADSL)基因、腺苷-磷酸脱氨酶(AMPD)基因、GARS-AIRS-GART基因、氨基咪唑氨甲酰核苷酸转甲酰基酶/次黄嘌呤核苷酸环水解酶基因(PURH)、谷氨酰胺磷酸核糖焦磷酸酰胺转移酶(GPAT)基因等是与肌苷酸合成代谢相关的基因。文章对以上基因的研究进展进行了分析和论述,以期为肉鸡的分子育种提供参考。     

不同品种鸡肌肉营养价值及风味的研究

为研究玫瑰冠鸡肌肉营养价值和肉质风味,以良凤黄鸡和科宝肉鸡作为对照,分别测定其胸肌和腿肌中的氨基酸和肌苷酸(IMP)含量。结果表明:玫瑰冠公鸡胸肌、腿肌的氨基酸总量、必需氨基酸和鲜味氨基酸含量均显著高于科宝公鸡(P0.05),玫瑰冠母鸡胸肌的氨基酸总量极显著高于科宝母鸡(P0.01),鲜味氨基酸含量显著高于科宝母鸡(P0.05);玫瑰冠鸡和良凤黄鸡的E/T值、FAA/TAA值均高于科宝肉鸡;玫瑰冠公鸡的胸肌、腿肌IMP含量均极显著高于科宝公鸡(P0.01);玫瑰冠母鸡胸肌IMP含量极显著高于良凤黄母鸡、科宝母鸡(P0.01),玫瑰冠母鸡腿肌IMP含量显著高于科宝母鸡(P0.05);玫瑰冠鸡的矫正肌苷酸(IMPc)含量高于良凤黄鸡和科宝肉鸡。综上所述,玫瑰冠鸡与良凤黄鸡、科宝肉鸡相比,肌肉营养更丰富、风味物质含量更高,结果为玫瑰冠鸡肉品质研究和种质资源评估、开发利用奠定了坚实的理论基础。     

家禽肌肉肌苷酸含量影响因素及其相关基因的研究进展

肌苷酸是影响肉质风味的重要物质基础,其鲜味呈味作用显著。家禽的品种、饲养方式、屠宰后的储藏条件以及日粮蛋能水平和饲料添加剂等是影响肌苷酸的含量主要因素。文章就肌苷酸的形成机理、影响因素及其相关基因的研究进展进行全面综述,为家禽肉质风味研究提供借鉴与参考。     

Edam干酪的特征滋味

对Edam干酪中乳酸、氯化钠、游离氨基酸以及游离脂肪酸4 种特征滋味物质进行测定,并通过口腔唾液、模拟唾液以及普通去离子水3 种处理方式对干酪样品进行处理,对比干酪中乳酸、氯化钠、游离氨基酸的含量,并用滋味活度值判定对干酪滋味的贡献,同时对干酪进行感官评价。结果表明：经3 种方式处理后,乳酸对干酪滋味无贡献;氯化钠主要赋予干酪咸味,且人体唾液和普通去离子水处理后的含量差异不显著;游离脂肪酸主要赋予干酪酸味和醇厚感,经人体唾液处理后,干酪中的游离氨基酸中的谷氨酸含量低于阈值,无法感知到鲜味;感官分析结果表明     

哺乳动物味觉感受器T1Rs受体家族及信号转导机制的研究进展

味觉受体第一家族（T1Rs）是一类能感知甜味和鲜味的受体家族,它包括T1R1,T1R2,T1R3三个成员。T1R2＋T1R3以异二聚体形式共表达参与甜味识别,而T1R1＋T1R3也以异二聚体形式共表达参与鲜味识别。良好的味觉能促进牛的食欲,促进生长发育,但目前关于牛的T1Rs受体家族的研究并不多见,有必要对这个受体家族做进一步探索。本文从甜味和鲜味两个方面对这一受体家族的分子结构及信号转导机制的最新研究进展做简要综述。     

Correlation between skeletal muscle fiber type and responses of a taste sensing system in various beef samples

The difference of muscle fiber type composition affects several parameters related to meat quality; however, the relationship between muscle fiber types and meat taste is unclear. To elucidate this relationship, we determined the taste of various beef samples using a taste sensor (INSENT SA402B) and analyzed its correlation with different muscle fiber type composition. We used 22 kinds of beef samples and measured nine tastes, including the relative and change of membrane potential caused by adsorption (CPA) values, using six sensors (GL1, CT0, CA0, AAE, C00, and AE1). The taste sensor analysis indicated positive value outputs for the relative C00, AAE, and GL1 values as well as for the CPA value of AAE, which corresponded to bitterness, umami, sweetness, and richness, respectively. We found significant positive correlations of the myosin heavy chain 1 (MyHC1) composition with umami taste, and with richness. This result suggests that high levels of slow MyHC1 can induce strong umami taste and richness in beef. We expect that our results will contribute to the elucidation of the relationship between muscle fiber types and meat palatability.     

动物鲜味受体的研究进展及其基因表达调控

动物的鲜味受体包括代谢型谷氨酸受体(m GluR)和味觉受体异源二聚体(T1R1/T1R3),是C型G蛋白偶联受体,N末端捕蝇草模块(VFT)区域可与鲜味配体结合,识别鲜味。本文主要论述了鲜味受体的研究进展、鲜味识别转导机制及鲜味受体基因的表达调控等,以期为相关研究提供参考。     

迪庆藏猪与野藏杂交猪肌肉全谱游离氨基酸味道强度值比较

本研究旨在探明迪庆藏猪与野猪×迪庆藏猪（野藏杂交猪）肌肉全谱游离氨基酸（FAA）味道强度值（TAV）的差异。选择胎次相同、出生日期相近、体重20 kg左右的迪庆藏猪和野藏杂交猪各12头（公、母各半）,以迪庆藏猪为对照,采用相同饲粮在相同饲养条件下直线育肥,100 kg左右屠宰,采集背最长肌,沸水蒸30 min后,用高效液相色谱-四级杆离子阱串联质谱仪检测其全谱游离氨基酸,计算呈味氨基酸TAV并比较其差异。结果显示,与迪庆藏猪相比,野藏杂交猪肌肉游离氨基酸总鲜味TAV降低16.27%（P<0.05）,总甜味、酸味和苦味TAV分别降低3.50%、11.68%和1.50%,但差异均不显著（P>0.05）;野藏杂交猪肌肉谷氨酰胺（Gln）鲜味TAV、甜味TAV均降低22.89%（P<0.05）,缬氨酸（Val）甜味、苦味TAV均增加36.32%（P<0.05）;天冬氨酸（Asp）、甘氨酸（Gly）、谷氨酸（Glu）与组氨酸（His）等其他游离氨基酸的鲜味、甜味、酸味和苦味TAV与迪庆藏猪间均差异不显著（P>0.05）。以上结果表明,与野猪杂交会降低迪庆藏猪肌肉鲜味TAV,降低Gln的鲜味、甜味TAV,提高Val甜味、苦味TAV,该结果可为迪庆藏猪的开发利用提供依据。     

Evaluation of changes in the taste of cooked meat products during curing using an artificial taste sensor

The purpose of this study was to assess an evaluation method using an artificial taste sensor, in comparison with chemical analysis and sensory evaluation of the taste of meat during curing. Samples of Canadian pork were treated with salt, nitrite and phosphate. Curing time ranged from 0 to 168 h. In the sensory evaluation, there were no significant differences in the all characteristic items at 72‐h cured sample compared to the 0‐h sample. Some of the characteristic items for the 168‐h sample (umami, overall taste, richness and overall palatability) showed significant difference (P < 0.05) compared to the 0‐h sample. Taste sensor analysis indicated that the sensor outputs of bitterness and saltiness were significantly correlated with curing time (R = 0.98 and 0.97, respectively), and total free amino acids (R = 0.91 and 0.96, respectively). The sensor output of bitterness was significantly correlated (R = 0.96) with the sum of amino acids corresponding to bitter taste. The increase in the chemical components contributing to bitterness and/or saltiness was indicated as the cause of the characteristic taste. Taste sensor analysis may be applicable as a qualitative method for evaluating taste characteristics generated during the curing of manufactured cooked meat products.     

Reduction of dietary lysine increases free glutamate content in chicken meat and improves its taste

Taste is a crucial factor of meat quality, and amino acids are important taste‐active components in meat. Here, the effects of dietary lysine (Lys) content on taste‐active components in meat, especially free glutamate (Glu), were investigated. Twenty‐eight‐day‐old broilers (Gallus gallus) were fed diets with graded Lys content of 90% or 100% of the recommended Lys requirement, (according to the National Research Council, 1994 ) for 10 days. Free amino acid content in meat and sensory scores of meat soup were estimated. Free Glu content, the main taste‐active component of meat, was significantly increased by a reduction of dietary Lys. Compared with the Lys 100% group (control), free Glu concentrations of meat were increased by 35.7% in the Lys 90% group (P < 0.05). In addition, free glycine, valine, isoleucine, leucine, histidine and threonine concentrations of meat were significantly increased in the Lys 90% group (P < 0.05). Sensory evaluation of meat soup made from the Lys 100% and 90% groups indicated different meat tastes. Sensory scores of taste intensity, umami and kokumi tastes were significantly higher in the Lys 90% group. These results suggest that a reduction of dietary lysine increased free glutamate content in meat and improved its taste.     

Regulation of taste-active components of meat by dietary leucine

1. Regulation of meat taste is one effective method for improvement of meat quality. In this study, effects of dietary leucine (Leu) content on taste-active components, especially free glutamate (Glu), in meat were investigated. 2. Broiler chickens (28 d old) were fed on diets with graded dietary Leu content (100, 130 or 150% of Leu requirement in NRC, 1994) for 10 d before marketing. Taste-active components of meat (free amino acids and ATP metabolites) and sensory score of meat soup were estimated. 3. Free Glu content, the main taste-active component of meat, was significantly increased by dietary Leu. Compared with the Leu 130% group, free Glu was increased by 17% in the Leu 100% group. Free Glu of meat tended to decrease in the Leu 150% group. In contrast, inosine monophosphate content in meat did not change among all groups. 4. Sensory evaluation of meat soup from the Leu 100 and 150% groups showed that they had different meat tastes. Sensory scores of overall preference, umami taste and chicken-like taste were significantly higher in the Leu 100% group. 5. These results suggest that dietary Leu content is a regulating factor of free Glu in meat. Decreasing dietary Leu induces an increase in the free Glu content of meat and improves meat taste.     

中草药添加剂对绵羊肌肉组织中鲜味物质含量的影响

试验旨在研究自拟中草药添加剂对绵羊肌肉组织中鲜味物质含量的影响。选用32只10月龄绵羊,随机分为4组,即试验1、2、3和4组。试验1组为对照组,饲喂基础日粮;试验2、3和4组在基础日粮中分别添加1%方剂Ⅰ、1%方剂Ⅱ和1%方剂Ⅲ,进行为期60 d的饲养试验,采用反相高效液相色谱（RP-HPLC）法检测肉样中肌苷酸（IMP）及其相关代谢物的含量。结果表明,所有试验样品中均不含三磷酸腺苷（ATP）成分,二磷酸腺苷（ADP）、次黄嘌呤（HYP）和一磷酸腺苷（AMP）的含量亦很低,且各组数据间均无显著差异（P>0.05）;3个中草药添加剂组均能不同程度的提高绵羊肉中IMP及其分解产物的含量,其中试验4组IMP、肌苷（INO）和校正肌苷酸（IMPc）值均极显著高于试验1组（P<0.01）,与试验2、3组相比亦存在显著差异（P<0.05）。提示,方剂Ⅲ能显著改善绵羊肉的风味。