不同月龄巴寒F_2羊和小尾寒羊肌肉中共轭亚油酸含量比较

选取巴寒F_2羊和小尾寒羊不同生长阶段、不同部位的骨骼肌,分别测定其总脂肪含量和共轭亚油酸(CLA)含量,研究不同品种、月龄及部位肌肉中总脂肪含量和CLA含量的差异,探讨宰后羊肉营养价值。结果表明:在同一月龄的相应部位,巴寒F_2的总脂肪含量都略高于小尾寒羊(P0.05);巴寒F_23个部位肌肉和小尾寒羊的背最长肌中的总脂肪含量随着月龄的增加而增加;巴寒F_2和小尾寒羊3个部位肌肉中c9,t11-CLA含量、t10,c12-CLA含量都随着月龄的增大先升高后降低,在6月龄时显著高于其它月龄(P0.05)。通过计算各部位的均值得出,巴寒F_2和小尾寒羊背最长肌中c9,t11-CLA的含量都较高;在4月龄时,巴寒F_2背最长肌中t10,c12-CLA含量显著高于股二头(P0.05);在5、6、8月龄时,小尾寒羊背最长肌含有较高含量的t10,c12-CLA。试验结果表明CLA的含量与羊的品种、月龄、部位具有相关性,推断月龄对其影响较大,CLA通过影响肉的营养价值,进而影响优质羊肉制品的生产。     

饲养方式和屠宰季节对乌珠穆沁羊肉肌内结缔组织特性的影响

饲养方式和屠宰季节对肌肉结缔组织特性影响较大,以不同饲养方式和屠宰季节的乌珠穆沁羊半腱肌和背最长肌结缔组织、肌内膜和肌束膜为研究对象,利用分光光度法测定其胶原蛋白含量及热溶解性,分别利用高效液相色谱仪和差示扫描量热仪测定吡啶诺林的含量和热变性温度。结果表明：饲养方式对乌珠穆沁羊背最长肌结缔组织、肌内膜和肌束膜的胶原蛋白含量影响显著（P＜0.05）;屠宰季节对自然放养乌珠穆沁羊背最长肌结缔组织、肌内膜的胶原蛋白含量影响显著（P＜0.05）;半腱肌结缔组织和肌内膜的胶原蛋白含量均受饲养方式和屠宰季节的显著影响（P＜0.05）;饲养条件和屠宰季节对乌珠穆沁羊背最长肌结缔组织、肌内膜中可溶解胶原蛋白和半腱肌和背最长肌结缔组织中吡啶诺林含量均影响显著（P＜0.05）;吡啶诺林含量越高的样品可溶解性胶原蛋白含量越低;半腱肌结缔组织、肌内膜和肌束膜的热变性温度低于背最长肌,相同屠宰季节时,自然放养乌珠穆沁羊肉的热变性温度高于圈养。     

不同月龄肉羊肌内结缔组织中Ⅴ型胶原蛋白的特性

采用自然放牧条件下的6、9、12、18 月龄乌珠穆沁羊,取其半腱肌（Semitendinosus,ST）和背最长肌（Longissimus dorsi,LD）,提取并分离纯化肌内结缔组织中的Ⅴ型胶原蛋白。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、傅里叶变换红外光谱（Fourier transform infrared spectroscopy,FTIR）、热变性温度和氨基酸组成分析,比较各月龄段肉羊不同部位中Ⅴ型胶原蛋白的特性。结果表明：Ⅴ型胶原蛋白主要由α1(Ⅴ)、α2(Ⅴ)、α3(Ⅴ) 3 种亚基组成;ST和LD肌内结缔组织中Ⅴ型胶原蛋白的含量随着月龄的增长而增加,且各月龄间差异显著（P＜0.05）;在同一月龄段,ST肌内结缔组织中Ⅴ型胶原蛋白的含量高于LD;FTIR分析表明,各月龄段ST和LD肌内结缔组织中的Ⅴ型胶原蛋白均出现了主要吸收峰酰胺A、B及酰胺Ⅰ、Ⅱ、Ⅲ;ST肌内结缔组织中Ⅴ型胶原蛋白的热变性温度随着月龄的增长而显著升高（P＜0.05）,但9、12 月龄间无显著差异（P＞0.05）;LD肌内结缔组织中Ⅴ型胶原蛋白的热变性温度随着月龄的增长而升高,但9、12 月龄及12、18 月龄间无显著差异（P＞0.05）,其他月龄均差异显著（P＜0.05）;氨基酸组成分析结果表明,Ⅴ型胶原蛋白的总氨基酸、亚氨基酸及羟脯氨酸含量随着月龄的增长而呈上升趋势,且各月龄间有显著差异（P＜0.05）。本研究解释了随着肉羊月龄的增加,其骨骼肌肌内结缔组织中Ⅴ型胶原蛋白的特性变化。     

肌肉胶原蛋白特性对嫩度的影响

本试验对不同月龄苏尼特羊不同部位的肌肉胶原蛋白特性进行了分析。其结果表明,随着月龄的增加,总胶原蛋白、可溶性胶原蛋白、不溶性胶原蛋白的含量都呈增加的趋势,而可溶性胶原蛋白的溶解度却在随月龄的增加呈下降的趋势。相关分析表明,肌肉的剪切值与总胶原蛋白、可溶性胶原蛋白为极显著正相关(P<0.01),胶原蛋白溶解度与剪切值成极显著(P<0.01)负相关。这些结果表明,通过测定肌肉胶原蛋白的含量可以较客观的评价肉的嫩度。     

苏尼特羊肌肉胶原蛋白发育性变化与嫩度的研究

选择自然放牧的3个不同月龄苏尼特羊2个不同部位的肌肉,用比色法测定胶原蛋白的含量,用高效液相色谱仪测定吡啶诺林(Pyr)的含量,用质构仪测定剪切值.结果表明,随着月龄的增加,总胶原蛋白、吡啶诺林的含量都呈增加的趋势,月龄之间差异显著(P<0.05).而胶原蛋白的溶解度随月龄的增加呈下降的趋势,且月龄之间差异显著(P<0.05).相关分析结果显示,肌肉的剪切值与总胶原、吡啶诺林呈极显著正相关(P<0.01),胶原溶解度与剪切值呈极显著负相关(P<0.01).苏尼特羊肉胶原蛋白特性在生长发育过程中有显著的变化,非还原性交联吡啶诺林的含量是影响肌肉嫩度的主要内在因素,不同部位、生长月龄对胶原蛋白含量及交联特性有显著影响.     

不同月龄对巴寒F_2肉羊营养品质变化规律的影响

试验选用4,5,6,8月龄巴寒F2肉羊的股二头肌、背最长肌和臂三头肌为试验肉样,通过测定其常规理化指标(水分、灰分、粗蛋白和粗脂肪)来分析研究不同月龄巴寒肉羊的不同部位营养品质变化情况。结果表明,整体来看,巴寒F2肉羊背最长肌(B)的水分含量高于臂三头肌(L)和股二头肌(G),其股二头肌相对其他两个部位的肌内脂肪含量最少,且6月龄成为巴寒肉羊水分和脂肪含量先增长后减小的拐点;而灰分和蛋白质均随着月龄的变化处于不断增加的趋势。     

不同部位鹿肉在成熟过程中化学成分和食用品质的变化

比较研究宰后成熟处理0、3、5、7、14、21d 的花- 马杂交F1 鹿较具代表性的背最长肌、半腱肌、冈上肌和腰大肌中主要化学成分和食用品质的变化。结果表明：部位因素对经过成熟处理鹿肉的主要化学成分和食用品质有一定的影响。成熟时间对不同部位鹿肉的水分含量、粗脂肪含量、剪切力值、解冻滴水损失和蒸煮损失有显著影响(P ＜ 0.05),而对胶原蛋白含量无显著影响(P ＞ 0.05)。背最长肌具有较高的粗脂肪含量和胶原蛋白含量,水分含量较低;剪切力和蒸煮损失明显小于其他3 个部位肉。成熟时间对背最长肌和半腱肌的剪切力有影响,而对冈上肌和成熟3d 后的腰大肌没有影响。     

不同部位牦牛肉品质比较分析

以18头舍饲育肥牦牛的背阔肌、臂三头肌、腰大肌、背最长肌、臀股二头肌、半腱肌6个部位的肌肉为研究对象,分别对其常规营养成分、矿物质元素及食用品质进行分析,研究牦牛不同肌肉部位的营养品质和食用品质之间的差异。研究结果表明：常规营养成分中,各部位除蛋白不存在显著性差异外（P>0.05）,其它指标均存在差异显著（P<0.05）,其中背阔肌的脂肪含量显著高于其它部位（P<0.05）;从矿物质元素来看,背阔肌的Ca、Na含量较其它部位高,半腱肌的K、Mg含量较高,臂三头肌的微量元素含量较丰富;从肉的食用品质上来看,腰大肌及背最长肌嫩度较好,臀股二头肌和背最长肌的持水力较其它部位强。结果表明,不同部位的肌肉在营养品质和食用品质方面均存在很大差异,综合看来,背最长肌的肉质较好,其次为臀股二头肌,为今后肉块分割增值技术及等级评价体系的建立提供依据。     

乌珠穆沁羊骨骼肌中脂肪酸的组成与相关基因表达量分析

采用不同月龄乌珠穆沁羊半腱肌,利用气相色谱仪和实时荧光定量PCR技术分别测定半腱肌中脂肪酸含量和PPARγ、FAS基因相对表达量。结果表明,从乌珠穆沁羊半腱肌中共检测出31种脂肪酸。其中饱和脂肪酸含量在月龄之间差异不显著(P0.05)。单不饱和脂肪酸含量在1至6月龄间逐渐增加,而1月龄和9月龄之间差异不显著(P0.05),3月龄和12月龄之间差异不显著(P0.05)。多不饱和脂肪酸含量9月龄和12月龄与6月龄相比有下降趋势。随着月龄的增加,单不饱和脂肪酸、多不饱和脂肪酸总体上呈上升趋势。饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸与PPARγ、FAS基因的相对表达量呈负相关。     

牛不同部位肌肉高铁肌红蛋白还原酶活力及耗氧率对肉色稳定性的影响

为了研究牛不同部位肌肉的高铁肌红蛋白还原酶活力(MRA)和肉的呼吸耗氧强弱对肉色泽稳定性的影响,本文以牛的三个部位的肌肉:背最长肌(LL)、半腱肌(ST)、腰大肌(PM)为研究对象,4℃避光贮藏5d,测定MRA、肌红蛋白(MMb)含量、耗氧率(OCR)等,探究肉色稳定性与牛肉部位、MRA和呼吸耗氧率之间的关系。结果表明,三种肌肉中,背最长肌的色泽稳定性最好,腰大肌最差,半腱肌介于中间;MRA越高的肌肉,肉色越稳定;OCR越低的肌肉,肉色越稳定。     

长途运输应激对西门塔尔牛不同部位肉品质指标的影响

为研究长途运输所产生应激对西门塔尔牛不同部位肉品质指标的影响,选取12 头西门塔尔公牛,随机分为运输组（运输距离＞600 km）和对照组（未运输组）,对其冷却排酸成熟72 h后背最长肌、半腱肌和冈上肌的pH值、色差值、持水力和剪切力进行测定。结果表明：与对照组相比,长途运输产生的应激反应导致西门塔尔牛肌肉宰后pH72 h值显著升高（P＜0.05）,冈上肌极显著升高（P＜0.01）;滴水损失率、蒸煮损失率和压力失水率显著增大（P＜0.05或P＜0.01）,但半腱肌的滴水损失率、背最长肌的蒸煮损失率和压力失水率在长途运输前后无显著差异（P＞0.05）;运输后3 个部位肉的剪切力增大,亮度值（L*）极显著降低（P＜0.01）,红度值（a*）和黄度值（b*）分别有不同程度的变化,b*仅在背最长肌中显著增大;长途运输后,除a*和b*之外,冈上肌的其他质量指标均变化显著（P＜0.05或P＜0.01）。运输应激对牛肉品质具有显著影响,会降低其品质,对不同部位肉的影响不同,其中冈上肌的变化程度最大。     

Intramuscular fatty acid profile of longissimus dorsi and semitendinosus muscle from Pateri goats fed under traditional feeding system of Sindh, Pakistan

The present study was undertaken to assess the intramuscular fatty acid composition of different muscles taken from male Pateri (n=15) goats, reared on naturally grown grasses, leaves and pods of Acacia nilotica and crushed cereal, under traditional way of feeding. Goats were slaughtered with an average weight of 68±7kg and age 12±1 month. The samples were taken from longissimus dorsi region (between the 12th and 13th rib) and distal region of semitendinosus muscle. Results of total fat content and fatty acids composition does not show significant (P>0.05) variation among muscles investigated. The fatty acid composition of muscles studied were primarily composed of oleic (31.50-33.38%), followed by palmitic acid (19.84-22.05%) and stearic acid (22.25-24.91%) respectively. Muscle tissue in general contained an average 51.13% of saturated fatty acids and 48.87% of unsaturated fatty acids. The mean conjugated linoleic acid was found 0.41%, 0.43% and 0.47% in ribeye and loin portion of longissimus dorsi muscle and distal region of semitendinosus muscle, respectively.     

Proportion of Collagen Types I and III in Four Bovine Muscles Differing in Tenderness

Intramuscular collagen containing both endomysial and perimysial tissue was extracted from four bovine muscles, analyzed for collagen types I and III, and related to total muscle collagen and meat tenderness. Isolated collagen was digested with cyanogen bromide and the proportion of collagen types I and III determined from densitometric scans of peptides resolved by SDS-PAGE. Total collagen was different (P<0.05) for each muscle. However, only the longissimus had more (P<0.05) type III collagen than did the biceps femoris, semimembranosus, and semitendinosus muscles. Percentage type III was correlated with sensory panel connective tissue amount (0.48) and overall tenderness (0.48) scores for the longissimus and biceps femoris muscles.     

Fatty acid composition of intramuscular lipids in various muscles of Holstein-Friesian bulls slaughtered at different ages

Holstein-Friesian bulls were slaughtered at 7, 14 and 19 months of age. Samples were collected from the psoas major, longissimus and semitendinosus muscles. The total lipids (TL) of the samples were extracted and the fatty acid compositions were analysed by gas chromatography. Both the slaughtering age and the type of muscles had significant effects on the intramuscular TL contents and fatty acid compositions. The longissimus muscle had higher intramuscular TL both at 14 and 19 months than at 7 months of age. As the bulls became older the proportion of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) increased in the TL of each muscle tested, whereas that of polyunsaturated fatty acids (PUFA) decreased. Among the muscle types, the semitendinosus had the lowest, intramuscular TL at each slaughtering age and the psoas major the highest. Except for SFA at 7 months of age, the semitendinosus showed lower levels of SFA and MUFA and higher proportions of PUFA than the other two muscles.     

Composition of Bovine Muscle Lipids at Various Carcass Locations

SUMMARY— Bovine intramuscular lipids extracted from the semitendinosus, triceps brachii and longissimus dorsi muscles were fractionated into phospholipids and neutral fats by silicic acid column chromatography. In spite of the wide range in total fat content at each location, phospholipids were present in all three muscles at a level of approximately 500 mg per 100 g of muscle tissue. This result, coupled with the lower total fat content of the semitendinosus as compared to the other two muscles, indicated a significantly higher percentage of phospholipid material in the total fat from the semitendinosus as compared to the triceps brachii or longissimus dorsi.
The fatty acids were identified in both lipid fractions using retention time data obtained on both a polar and a non-polar column. The identity of the unsaturated fatty acids was confirmed when their peaks did not appear on the chromatographs obtained from brominated samples. There was significantly more C14:0 in the longissimus dorsi neutral fat fractions than in the semitendinosus neutral fat fractions. In the phospholipids, there was significantly more C16:0 and significantly less C18:0 in the longissimus dorsi as compared to either the semitendinosus or triceps brachii. Although the two lipid fractions of the longissimus dorsi contained slightly higher percentages of total saturated fatty acids than the corresponding fractions in the other two muscles, the effects were not significant.     

Pyridinoline Cross-links in Bovine Muscle Collagen

Development of muscle collagen cross-linkage was investigated by determining hydroxylysylpyridinoline and lysylpyridinoline contents of longissimus dorsi, semitendinosus and extensor carpi ulnaris muscles. These were removed from male, female and castrated German Simmental cattle (150–620 days old) fattened on different energy levels and related to possible influences of sex, feeding intensity and type of muscle. In intramuscular collagen, an age-related increase in pyridinoline content was found. Cross-link formation was also influenced by sex and feeding intensity. Epimysia exhibited differences in pyridinoline content which were probably due to differences in physical strain of the muscles.     

Intramuscular fatty acid profile of longissimus dorsi and semitendinosus muscle from Kundi steers fed on pasture with cottonseed cake supplement

The present study was accomplished to evaluate the intramuscular fatty acid (FA) composition of different muscles taken from Kundi steers (n = 15), which were approximately 24 months old, fed on a cottonseed cake supplement, and were made to graze on alfalfa pasture for 95 days prior to slaughter. The samples were taken from longissimus dorsi region (loin and ribeye portion) and distal region of semitendinosus muscle for intramuscular FA analysis. Saturated FA, comprising 49.48–52.09% of total FA composition, in all the muscles were studied. Ribeye portion of longissimus dorsi muscle contain relatively higher (P > 0.05) amount of trans FA (3.37%) as compared with loin portion of longissimus dorsi muscle (3.1%) and distal region of semitendinosus muscle (2.84%). The sum of monounsaturated FA in all the muscles studied was estimated in the range of 32.21–34.64%, while polyunsaturated FA contribute 11.39–12.39% of total FA. The mean conjugated linoleic acid was found to be 0.28, 0.35 and 0.41 in ribeye and loin portion of longissimus dorsi muscle and distal region of semitendinosus muscle, respectively.     

屠宰日龄对伊拉兔胴体和肉质量的影响

对伊拉兔在60、70、80 日龄屠宰的胴体和肉质量进行比较研究,结果表明：宰前活质量、热胴体质量、冷却胴体质量、参考胴体质量、屠宰率、肾周脂肪质量/参考胴体质量、可解剖脂肪质量/参考胴体质量均随日龄的增加而明显增大（P＜0.05）;胴体的滴水损失随日龄增大而明显减少（P＜0.05）;pH24 h值随日龄增加有下降趋势;股二头肌L*、a*值在70 日龄和80 日龄组间无显著差异（P＞0.05）,背最长肌L*、a*值在各日龄组间无显著差异（P＞0.05）;背最长肌系水力和剪切力在70 日龄和80 日龄组间无显著差异（P＞0.05）,且均大于60 日龄;背最长肌的蒸煮损失随日龄增加而明显减小（P＜0.05）;背最长肌和后腿肌的粗蛋白、粗灰分含量在各日龄组间无显著差异（P＞0.05）,粗脂肪含量随日龄增大而明显增加（P＜0.05）,而水分含量有一定减小。伊拉兔在60 日龄屠宰生长潜力未充分发挥,70 日龄屠宰效益好,80 日龄屠宰改善了胴体和肉的品质。     

Factors Affecting Collagen Solubility in Bovine Muscles

SUMMARY— Solubility of intramuscular collagen was studied as affected by chronological maturity in 15 bovine longissimus dorsi and 15 semimembranosus muscles and as affected by post-mortem contraction state in the semitendinosus of 7 animals. Collagen solubility decreased significantly with each advancing maturity group in both longissimus dorsi and semimembranosus muscles. Collagen solubility was also higher (P < 0.05) in the longissimus dorsi than in the semimembranosus, except in the E maturity group. It was also related to panel tenderness in both muscles (r = 0.77 and 0.81 (P < 0.01) for longissimus dorsi and semimembranosus muscles, respectively. However, within-maturity group correlations of solubility of collagen and tenderness were low and nonsignificent.
Collagen content did not differ significantly in longissimus dorsi muscles of animals of A, B, and E maturity groups; however, the semimembranosus had more collagen (P < 0.05) in E than in A and B maturity groups. Collagen content was not related (P > 0.05) to panel tenderness in either muscle (r =−0.42 and −0.48 for longissimus dorsi and semimembranosus, respectively). Neither collagen solubility nor collagen content was significantly affected by post-mortem contraction state. Furthermore, collagen solubility did not increase significantly with post-mortem aging up to ten days.