中国研究猪背最长肌和半腱肌肌内脂肪含量和前体脂肪细胞分化过程中的差异

正消费者对具有明显大理石花纹特征猪肉需求的增加,使得研究者开展了大量有关脂肪组织和脂肪细胞等的研究,证实肌内脂肪对提升肉品质具有重要作用。尽管猪半腱肌、背最长肌和腰大肌存在多处生物化学和组织学上的差异,但是猪半腱肌、背最长肌、腰大肌在肌内脂肪含量和肌肉前体脂肪细胞方面存在的差异还没有详细的报道,猪背最长肌和半腱肌肌内脂肪的生     

牛背最长肌颜色与功能特性之间的关系研究

实验选取浅红色、鲜红色、深红色和黑色4种颜色的牛背最长肌,分析其感官品质、营养价值、加工特性方面的差异。结果表明,随着肉样颜色的变深,其pH显著升高(P<0.05)。营养和感官方面,4种颜色的牛背最长肌没有显著的差异(P>0.05),而在加工方面差异较大。黑色肉的凝胶保水性、凝胶强度、凝胶弹性和蒸煮损失显著的优于其他组(P<0.05),但其乳化能力显著的低于其他3组(P<0.05)。     

来自牛半腱肌肌束膜和肌内膜胶原蛋白热力学特性分析

探讨牛半腱肌肉肌束膜和肌内膜胶原蛋白热力特性的热诱导变化。牛半腱肌肉分别采用水浴和微波加热到内部终点温度分别为20、40、50、60、70、80℃和90℃,用示差扫描量热法研究肌束膜和肌内膜胶原蛋白热力特性(起始、最高和最终热收缩温度)在热处理过程中的变化。结果表明：牛半腱肌肉肌束膜和肌内膜胶原蛋白的热收缩温度在两种热处理方式间都存在显著差异,在两种热处理方式中,内部终点温度60℃是影响肌束膜和肌内膜胶原蛋白热收缩温度的关键加热温度。热诱导的肌束膜和肌内膜胶原蛋白热力特性的变化是水浴和微波加热牛肉胶原蛋白热收缩温度存在差异的主要原因。     

巴西内洛尔牛不同部位肉品质特性分析

探究巴西内洛尔牛不同部位肉品质特性的差异及加工适宜性,为巴西内洛尔牛的精细化加工提供理论依据。本实验选取36月龄巴西内洛尔牛,腱肉、臀肉、肩肉、大黄瓜条、霖肉和腩肉等6个部位肉样,进行营养及食用品质特性等方面的研究。结果表明:巴西内洛尔牛6个部位之间肉品质特性具有较大差异。腱肉的解冻损失（4.65%）低,胶原蛋白含量（25.77%）较高;肩肉拥有良好的色泽（L*值40.34）但保水性较差;臀肉具有良好的嫩度、保水性、乳化特性和凝胶特性;霖肉蒸煮损失（26.44%）较大,但胶原蛋白含量较高且乳化特性和凝胶特性较好;大黄瓜条脂肪含量（6.26%）高,蒸煮损失低,肌间脂肪明显;腩肉呈现出解冻损失（4.64%）低,蒸煮损失（19.38%）高的特点。巴西内洛尔牛不同部位肉的品质特性存在较大差异,针对各部位肉之间的差异,选择适宜的加工方式。霖肉适宜于肉糜类产品的加工;腩肉适宜于冷冻储藏类产品的加工;肩肉可以采用肉糜类和烤制的加工工艺;臀肉可以采用蒸煮、酱卤、干制和烤制的加工方式;腱肉适宜于蒸煮和酱卤类产品的开发;大黄瓜条适宜于蒸煮和烤制的加工工艺。     

KCl和MgCl2部分替代NaCl对猪肉肌原纤维蛋白乳化凝胶特性的影响

研究KCl和MgCl2部分替代NaCl对猪肉肌原纤维蛋白乳化凝胶特性的影响,以期找到在保证乳化型肉制品产品良好品质条件下降低食盐含量的方法。结果表明,对比低钠组,KCl部分替代NaCl后显著增加肌原纤维蛋白溶解度、黏度、乳化稳定性和乳化能力,改善乳化凝胶的黏弹性,降低乳化凝胶汁液流失,提高产品出品率。而MgCl2部分替代NaCl对肌原纤维蛋白在降低食盐含量后产生的乳化特性劣变没有明显改善,但能提高肌原纤维蛋白乳化凝胶的黏弹性并降低汁液流失。     

云岭牛不同部位肉的品质特性分析

为了探索云岭牛不同部位肉品质特性的差异,选用30月龄云岭牛霖肉、臀肉、肩肉、牛腱、黄瓜条和牛腩6个部位肉,对水分、脂肪、蛋白质和胶原蛋白含量、p H值、色差、质构、剪切力、蒸煮损失、解冻损失、凝胶特性及乳化特性进行测定。结果显示:相较于其它品种的牛,云岭牛具有蛋白质含量高,脂肪含量低的特点。肩肉的水分(75.80%)、蛋白质(24.00%)和胶原蛋白含量(13.68%)高,脂肪含量(1.05%)低,凝胶特性、嫩度和保水性均较好,但乳化特性较差;霖肉的蛋白质含量(21.30%)最低,但脂肪(5.13%)和胶原蛋白含量(17.91%)最高;臀肉的凝胶特性和乳化特性较好。结果表明,云岭牛不同部位肉间的品质特性有显著性差异,肩肉适合块状产品开发;霖肉适合烤制产品的开发;臀肉适合肠类产品开发。     

淀粉与转谷氨酰胺酶复配引起肌肉蛋白功能特性的变化

在60、70?℃加热条件下,利用添加马铃薯淀粉（0%、1%、2%、3%、4%）和外源转谷氨酰胺酶（transglutaminase,TG）（0%、0.10%、0.30%、0.50%和0.70%）的鲤鱼肌原纤维蛋白进行热诱导凝胶的制备,通过分析添加物对肌原纤维蛋白功能特性（凝胶性和乳化性）和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE）图谱的变化,研究淀粉和TG复配对鲤鱼肌原纤维蛋白功能特性的作用。结果表明：在同一温度条件下,马铃薯淀粉和TG的添加对肌原纤维蛋白凝胶特性具有影响,凝胶的硬度和弹性随着添加量的增加而增大,且差异性显著（P＜0.05）。不同温度条件下凝胶的白度值差异不明显（P＞0.05）,70?℃与60?℃相比凝胶保水性有所增加。马铃薯淀粉和TG的添加对肌原纤维蛋白的乳化活性并没有明显的作用,但是对乳化稳定性有较大影响,随添加量的增加其变化趋势表现为先增大后减小,当马铃薯淀粉、TG添加量分别为2%和0.5%时乳化稳定性达到最大值94.5%。对SDS-PAGE图谱分析可知：马铃薯淀粉及TG添加使肌原纤维蛋白的主要蛋白质如肌球蛋白重链、肌动蛋白带等条带强度减弱。因此,蛋白质的结构和功能特性明显受到了淀粉和TG添加量的影响。     

水浴加热对牛半腱肌冷藏形成彩虹色斑的影响

研究水浴加热对牛半腱肌冷藏条件下形成彩虹色斑的影响。以新鲜牛半腱肌为实验材料,对其进行水浴(97℃)加热处理,使中心温度分别为70、80、90℃,在4℃条件下冷藏0～5 d,研究彩虹色斑强度、非血红素铁含量、蛋白质与脂质氧化、色泽等相关指标的变化,探讨水浴加热对牛半腱肌冷藏形成彩虹色斑的影响。结果表明,随水浴加热温度的升高和冷藏时间的延长,牛半腱肌彩虹色斑强度不断增强,其中亮度值(L*)和黄度值(b*)总体略有升高,而红度值(a*)略有降低,均出现显著差异(P<0.05);冷藏期间,牛半腱肌的非血红素铁含量、硫代巴比妥酸反应物(thiobarbituric acid reactive substance,TBARs)值、羰基含量显著升高(P<0.05),游离巯基含量显著降低(P<0.05);通过相关性分析得知,牛半腱肌彩虹色斑强度与非血红素铁含量、羰基含量、TBARs值呈显著正相关(P<0.05),与游离巯基含量呈显著负相关(P<0.05),与a*呈极显著负相关(P<0.01),可能是由于较高的非血红素铁含量促进TBARs值在冷藏0～1 d时迅速上升,同时促进蛋白质氧化进程,蛋白质与脂肪氧化过程同时发生,相互促进,从而共同影响彩虹色斑的形成。     

酸碱度对兔肉肌原纤维蛋白功能性质的影响

研究了不同酸碱度条件对兔肉肌原纤维蛋白功能特性的影响,以及肌原纤维蛋白功能特性指标间的相关性,并通过蛋白质三级结构的变化对其机理进行初探。研究发现,随着pH逼近等电点范围,蛋白质内部芳香族氨基酸不断暴露,蛋白的三级结构展开,表面疏水性不断变大,使得蛋白质分子间疏水相互作用增加。肌原纤维蛋白结构的变化引起蛋白质溶解度下降,并且伴随着乳化活性减小以及乳化稳定性的变化。同时这种结构变化导致肌原纤维蛋白流变学特性的变化,pH值减小导致剪切应力变小,并且在近等电点时,剪切应力存在明显变化。随着pH值不断减小,肌源性蛋白凝胶硬度不断增大,并且在近等电点时变小;同时凝胶保水性不断下降,而凝胶白度不断增大。     

国外牛胴体产量级评定方法及仪器分级现状

产量级是按牛胴体产肉率的高低对胴体进行的等级划分;肉质级是从肉的可食性来划分胴体等级。产肉量和肉质是胴体品质不可缺的两个方面,胴体品质则由二者综合确定。产量级是牛胴体分级体系的重要组成部分,该分级方法及标准的客观性、科学性、先进性将直接影响到屠牛产肉量的提高。 多年来许多国家都将眼观评定做为唯一的方法,即按胴体形状和皮下脂肪分布性质查明胴体品质的差异,但该法有时不能反映胴体的肌肉充实度,所以具有很大的主观性。近年来,许多国家都对牛     

基于图像的牛肉大理石纹理自动评级方法研究

研究一种基于图像处理技术的牛肉大理石花纹自动等级评定方法。通过图像重采样、单阈值分割、形态学腐蚀及膨胀等方法分割出大理石花纹,再提取图像的特征参数组,并用多元回归分析的方法构造牛肉大理石花纹评级模型,并用VC++实现了自动评级软件。通过对多个牛肉图像的检测,表明此评级计算模型具有良好的准确性和鲁棒性。     

The relationship of physiological maturity and marbling judged according to Korean grading system to meat quality traits of Hanwoo beef females

Fifty seven carcasses from Hanwoo beef females were randomly selected by official meat graders and were sorted into three levels of maturity and marbling. Carcass data was collected for back fat thickness, longissimus area, carcass weight, meat colour, fat colour, marbling score, yield and quality grades. Mature carcasses had more yellow fat, coarser texture, a larger longissimus muscle area and lower quality grades and marbling scores (P<0.05). Carcasses with a higher marbling score had thicker fat and a higher quality grade. Carcasses with low marbling had a higher yield grade and a coarser texture (P<0.05). Higher marbling scores corresponded with lower cook and drip loss values for longissimus steaks. As the maturity of carcass was increased, the redness and lightness of meat and the yellowness of fat all tended to increase. Tenderness, flavour and overall acceptability scores for the older maturity group were lower than for younger and intermediate groups. Marbling was significantly (P<0.01) correlated with quality grade, crude fat content, cook and drip losses, and Warner-Bratzler shear force. The maturity level was also significantly (P<0.01) correlated with quality grade, fat colour, texture score, number of calves produced and milk teeth, meat redness and yellowness, fat yellowness, and Warner-Bratzler shear force. Results indicate that a low marbling group and older maturity group based on Korean grading system could negatively influence carcass traits and beef qualities of Hanwoo beef female.     

牛眼肌区域大理石花纹评级特征的研究

针对我国牛肉分级制度中的大理石花纹等级评定特征不确定的问题,提出用几何、粒度及形状参数来表征花纹几何、形状及分布特点的方法。选择对牛肉大理石花纹等级评定起主要作用的特征参数,对中国、美国及日本3个国家的牛肉等级图进行深入地研究,找寻3个国家牛肉大理石花纹分级标准的侧重点。对选取的参数数据进行相关性分析,剔除原特征集中相关性较强的特征,应用主成分分析法对影响大理石花纹等级的参数进行线性组合,选取适合的主成分建立大理石花纹的等级预测模型。     

Influence of vitamin A on the quality of beef from the Tajima strain of Japanese Black cattle

Influence of vitamin A on the beef quality of the Tajima strain of Japanese Black cattle was studied. Marbling scores were correlated with serum vitamin A concentrations just before slaughter (r = -0.38). The mean marbling score of the low vitamin A group that were not supplemented with vitamin A after 15 months of age was significantly higher than that of the group supplemented with high vitamin A. However, there was no significant difference in the marbling scores between the group that were not given vitamin A after 23 months of age and the high vitamin A supplemented group. These results suggest that vitamin A supplementation affects carcass marbling only if given before 23 months of age, in these cattle.     

边缘检测、二值化处理进行牛肉分级的应用

采用图像处理技术自动估算牛肉眼肌横切面特征值,为基于计算机视觉的牛肉品质自动分级检测奠定基础.以牛胴体6～7肋横断面图像为试验材料,采用边缘检测、二值化处理技术等,运用VisualC++6.0编程语言,对牛肉眼肌的眼肌面积、脂肪、肌肉总面积比、脂肪分布均匀度、眼肌圆度、肌肉和脂肪色度值5个特征参数进行特征提取和检测.结果表明:经测量所得的眼肌面积越大,圆度越大,肌肉和脂肪色度值越高、大理石纹密度分布均匀的牛肉品质越好,相反,眼肌面积小、圆度小、肌肉和脂肪色度值越低、密度分布不均匀的牛肉品质低.该设计可有效计算眼肌面积和特征参数,能代替常规分级方法,实现牛肉质量等级的自动判别.     

Effects of metabolic modifiers on carcass traits and meat quality

Much research has been conducted and published about metabolic modifiers that increase growth rate, improve feed efficiency, increase carcass leanness, and decrease carcass fatness. Most of these metabolic modifiers have been developed to improve efficiency and profitability of livestock production and to improve carcass composition, with fewer of them developed and researched specifically to improve meat quality. Some of the metabolic modifiers can have negative effects on visual and sensory meat quality, especially when not used as recommended. This review evaluates the various kinds of metabolic modifiers that have been researched for their effects on production efficiency, carcass composition, and meat quality. Nutritional composition of meat generally is improved from use of most of the metabolic modifiers, visual quality is improved by others, but some can have a negative effect on marbling and tenderness. Anabolic steroid implants are very cost effective and practical for beef cattle production but aggressive implants used within 70 days of slaughter or too frequent use of them will reduce tenderness and marbling. Somatatropin and approved β-agonists are very effective in improving growth performance and carcass leanness in pigs, and β-agonists are effective in cattle, but improper use of them can have negative effects on marbling and tenderness. Feeding supplemental levels of vitamin E is quite beneficial for improving meat color and shelf-life of beef, lamb, and pork, whereas not supplementing diets with vitamin A has potential for improving marbling in cattle. Immunocastration shows promise for capitalizing on the efficiency of muscle growth of young boars up to a few weeks before slaughter, at which time boar taint is prevented and marbling is improved by immunocastration. Potential exists for improving the fatty acid profile of lipids and increasing conjugated linoleic acid content in beef through dietary manipulation. Supplementing swine diets with conjugated linoleic acid can improve carcass composition of swine, but is not yet cost effective to use. Dietary inclusion of magnesium, manganese, or chromium in diets of pigs and sheep has potential to improve meat color and water-holding capacity. Although, not all of these metabolic modifiers are approved in all countries, proper use of the ones that are approved offers opportunities for economically improving production efficiency and carcass leanness while maintaining acceptable marbling and tenderness, while some provide opportunities to enhance meat color and quality.     

基于深度学习的牛肉大理石纹智能分级研究

目的开发客观、准确、无损的基于深度学习的牛肉大理石纹智能化分级技术。方法将深度学习的图像识别方法应用于牛肉大理石纹的特征提取和分类上,并进行相应的调试和学习。结果通过计算机调试和学习,评级正确率分别达到84.2%(一级)、89.4%(二级)、81.9%(三级)、84.1%(四级)、82.6%(五级)。各级牛肉的识别率均在80%以上,识别时间都在1 s以内,达到了预期目标。结论将深度学习的图像识别方法应用于牛肉大理石纹的特征提取和分类上,评级准确率非常高,且随着图片数据库样本数的不断增多,其识别的准确度将不断提高,可进行大量推广使用。     

基于不变矩和改进SVM的牛肉大理石纹评级

针对牛肉大理石纹人工评级过程中人为误差干扰大的问题,研究利用图像处理技术提高牛肉大理石纹评级的客观性并增强自动化程度,提出基于不变矩、灰度共生矩阵和混沌蜂群优化混合核函数支持向量机(Support Vector Machine,SVM)的牛肉大理石纹评级法。首先计算牛肉大理石纹图像的不变矩和灰度共生矩阵统计量并由此构造特征向量;然后将训练和测试样本输入到混合核函数SVM,采用混沌蜂群算法优化SVM中的惩罚因子及核参数,使其分类识别性能达到最优;最后输入待评级样本进行分类识别,得到最优评级结果。大量实验结果表明:根据我国NY/T676-2010牛肉大理石纹标准图谱,评级正确率分别达到100%(一级)、93.3%(二级)、93.3%(三级)、96.7%(四级)、100%(五级)。与基于灰度矩和SVM法、基于灰度共生矩阵和BP(Back Propagation)神经网络法相比,本文所得评级正确率最高,且与专业评级师的实际评级情况最相符。     

Managing meat tenderness

This paper discusses the management of meat tenderness using a carcass grading scheme which utilizes the concept of total quality management of those factors which impact on beef palatability. The scheme called Meat Standards Australia (MSA) has identified the Critical Control Points (CCPs) from the production, pre-slaughter, processing and value adding sectors of the beef supply chain and quantified their relative importance using large-scale consumer testing. These CCPs have been used to manage beef palatability in two ways. Firstly, CCPs from the pre-slaughter and processing sectors have been used as mandatory criteria for carcasses to be graded. Secondly, other CCPs from the production and processing sectors have been incorporated into a model to predict palatability for individual muscles. The evidence for the importance of CCPs from the production (breed, growth path and HGP implants), pre-slaughter and processing (pH/temperature window, alternative carcass suspension, marbling and ageing) sectors are reviewed and the accuracy of the model to predict palatability for specific muscle×cooking techniques is presented.     

Image texture features as indicators of beef tenderness

Image processing techniques were developed to predict cooked-beef tenderness from fresh-beef image characteristics. Cattle from different finishing treatments were processed in a commercial plant. Two short loin steaks were sampled from each carcass; one used for sensory evaluation and the other for imaging. The samples varied significantly in both US quality grades and sensory tenderness scores. Color, marbling and texture features were extracted from the beef images. Statistical and neural network analyses were performed to relate the image features to sensory tenderness scores. Image texture features were found to be useful indicators of beef tenderness. Partial least squares and neural network models were able to predict beef tenderness from color, marbling and image texture features to R(2)-values up to 0.70.