Woody Breast短期贮藏中肉质的变化

为研究近年来速生型肉鸡鸡胸肉硬度缺陷(woody/wooden breast,WB)俗称"木质肉"在短期贮藏中生肉肉质参数的变化。实验选取68只42日龄Cobb 500肉鸡作为研究对象,经宰杀后人工分级为低(normal,NORM)、高(severe,SEV)两组(n=34只/组)。在不同时间节点下(1、3、8 d)对所有样本测定质量、挤压力(compression force,CF)、滴水损失(drip loss,DL)、肌节长度(sarcomere length,SL)及肉破碎化指数(gravimetric fragmentation index,GFI)。对所有参数进行组间(不同WB等级间,不同时间节点)显著性分析,同时对各参数与WB等级间进行相关性分析。结果表明:SEV样本质量、CF、SL、GFI在贮藏时间节点处都显著高于NORM样本(P0.05),DL在1 d时NORM与SEV间无差异,在3~8 d时显著上升(P0.05)。CF、SL、GFI在1~3 d时,所有样本都显著减小(P0.05),3~8 d时CF无显著变化(P0.05),SL、GFI在NORM样本间无差异但在SEV样本间继续减小(P0.05)。相关性分析表明,CF、累积DL与WB等级极显著相关(P0.01),SL、GFI随时间变化与WB硬度减小存在联系。综上可知,SEV生肉肉质较NORM差,WB硬度随贮藏时间变长而减小,但其生肉品质并不会发生改变,因此对WB检测应在宰杀当天在线进行,且WB硬度由多种原因共同作用导致。     

木质鸡胸肉生肉品质表征及检测方法研究

目的探索木质肉(woody/wooden breast,WB)生肉品质特性差异及客观检测方法。方法对不同木质鸡胸肉等级样本的重量、挤压力(CF Probe、CF TA-25)进行检测,同时在剪切实验中以剪切力(MORSF)、剪切做功(MORSE)及剪切峰值个数(PC-MORS)作为生肉质构分析指标。结果重量、CF Probe、CF TA-25、MORSF、MORSE、PC-MORS随着WB等级的递增而显著增大,2种硬度检测探头均可用于鸡胸肉的硬度检测。PC-MORS在MORSF和MORSE的基础上可有效区分WB等级,同时可显示鸡胸肉肌肉内部的层状结构信息。各测量指标之间存在不同程度的相关性,其中重量、CF Probe、MORSE、PC-MORS与WB等级之间存在极显著相关。建立的BP神经网络模型区分正常肉和木质肉的总体识别率达90.6%。结论本研究确定了木质鸡胸肉生肉硬度检测方法、质构分析的特征参数,并研究其木质化等级判定模型,研究结果可为后续木质鸡胸肉在线检测分级装置的研发提供一定的理论支撑。     

宰前急性淋浴对黄羽肉鸡应激生理生化指标及肉品质的影响

针对华南地区肉鸡屠宰场普遍存在对肉鸡进行宰前急性淋浴处理的现状,研究了宰前急性淋浴对黄羽肉鸡生理生化指标及肉品质的影响。结果表明,急性淋浴组黄羽肉鸡宰后沥血量(45.58±7.96)g,显著小于对照组沥血量(52.64±8.02)g(p0.05);血浆中促肾上腺皮质激素(ACTH)含量(42.84±1.28)ng/L,极显著大于对照组(30.99±0.06)ng/L,血浆皮质酮激素(CORT)含量(35.95±3.31)ng/m L,极显著大于对照组(16.42±1.50)ng/m L(p0.01);宰后45 min鸡胸肉和鸡腿肉中糖原含量、L*值均显著小于对照组(p0.05);宰后24 h鸡胸肉和鸡腿肉乳酸含量均显著小于对照组,且p H、滴水损失率、剪切力值均显著大于对照组(p0.05)。宰前急性淋浴增加了黄羽肉鸡的应激反应,使宰后肉品质降低。     

不同品种及部位鸡肉对风鸡加工适应性的影响

通过比较不同品种(817肉杂鸡、AA肉鸡和海兰褐蛋鸡)鸡胸肉和鸡腿肉风干制品的理化指标(出品率、色泽、水分含量、剪切力、硬度、弹性、凝聚力和咀嚼性)、感官品质(滋味、香气、质地、色泽和总体接受度)和营养指标(游离氨基酸),筛选适合于加工风干鸡肉制品的最佳原料。结果表明:海兰褐蛋鸡风干制品的出品率和水分含量最高,AA肉鸡次之,817肉杂鸡最小(P0.05);AA肉鸡风干制品的亮度值(L~*)和黄度值(b~*)均显著高于817肉杂鸡和海兰褐蛋鸡;海兰褐蛋鸡胸肉风干制品的质构指标数值均显著较高(P0.05),AA肉鸡风干制品比较适宜;海兰褐蛋鸡胸肉、817肉杂鸡胸肉、817肉杂鸡腿肉和AA肉鸡腿肉风干制品的总体接受度得分较高;817肉杂鸡胸肉和AA肉鸡腿肉风干制品的总游离氨基酸和风味氨基酸含量较高。综上所述,AA肉鸡腿肉和胸肉最适合制作成风鸡产品,817肉杂鸡比较适合,海兰褐蛋鸡不适合。     

云南剥隘鸡与河南肉鸡肉质食用品质的比较分析

对云南剥隘鸡与河南肉鸡在不同月龄(5月龄、7月龄)、性别及胴体部位(胸肌、腿肌)的鸡肉开展主要化学成分(水分、蛋白质、脂肪)及肉质评价指标(肉色、肌肉pH值、嫩度)的测定,以期比较分析两种鸡肉质食用品质的差异性。结果表明:(1)不同月龄的剥隘鸡与河南肉鸡肌肉水分、蛋白质及粗脂肪含量相近,肌肉L*值和b*值显著高于同月龄的河南肉鸡(P0.05),但肌肉嫩度值相反(P0.05);(2)不同性别的剥隘鸡与河南肉鸡肌肉水分、蛋白质含量及pH值没有显著差别(P0.05),母鸡肌肉粗脂肪含量、L*值、a*值和b*值高于河南肉鸡母鸡(P0.05);(3)不同胴体部位的剥隘鸡与河南肉鸡肌肉水分含量、p H值没有显著差异(P0.05),胸肌、腿肌的蛋白质、粗脂肪含量及a*值、b*值均高于同胴体部位的河南肉鸡(P0.05),但肌肉嫩度值相反(P0.05)。     

饲粮粒度对肉仔鸡生产性能及消化道发育的影响

研究饲粮粒度对肉仔鸡生产性能及消化道发育的影响,60只1日龄AA+公、母混合雏随机分成2个处理组,分别饲喂细粒、粗粒饲粮至14日龄。结果表明:与细粒饲粮组相比,饲喂粗粒饲粮组肉仔鸡平均日采食量、平均日增重极显著提高(P0.01),料重比极显著降低(P0.01),十二指肠绒毛、空肠绒毛、回肠绒毛高度极显著增长(P0.01);十二指肠、回肠绒毛隐窝深度差异不显著,空肠绒毛隐窝深度极显著减小(P0.01);十二指肠、空肠、回肠肠壁厚度极显著变薄(P0.01)。     

不同油脂对肉鸡生长性能、器官指数、血清生化指标的影响

为研究肉鸡饲料中不同油脂添加对肉鸡生长性能、器官指数、血清生化指标的影响,试验选取1日龄雄性爱拔益加(AA)肉鸡45只,随机分成3组,每组5个重复,每个重复3只,其饲料中油脂添加分别为豆油、猪油、豆油与猪油1∶1调和油(调和油),试验共42 d。结果表明,3种油脂对肉鸡平均日增重(ADG)无显著差异(P0.05),但添加调和油组ADG略高,豆油组平均日采食量(ADFI)显著低于猪油组、调和油组(P0.05),饲料添加豆油组肉鸡料肉比(F/G)极显著低于猪油组(P0.01);3种油脂对肉鸡胸腺指数、脾脏指数、法氏囊指数、肝脏指数均无显著影响(P0.05)。血清生化检测结果表明,3组间TP、AST、CHE、AMY、CK含量无显著差异(P0.05),豆油组HDL-C/LDL-C的比值显著高于猪油组(P0.05),且血清TC含量显著低于猪油组(P0.05);调和油HDL-C/LDL-C、TC含量与豆油组、猪油组无差异显著性(P0.05);猪油组UA、UREA含量极显著高于豆油组(P0.01),Crea水平极显著高于调和油组(P0.01);豆油组α-HBDH水平显著高于猪油组(P0.05),但与调和油组无显著差异(P0.05)。相比于豆油或猪油,饲料中添加调和油可提高平均日增重,且有益于肉鸡的心脏功能以及肝、肾功能。     

赞比亚不同蛋白质来源的饲料对肉鸡生长性能、屠宰性能及经济效益的影响

研究探讨赞比亚不同蛋白质来源的饲料对肉鸡生长性能、屠宰性能及经济效益的影响。试验采用单因素完全随机试验设计,选择21日龄的科宝500肉仔鸡1 800只,分为3个处理组,即豆粕组、杂粕组1(豆粕+DDGS+棉粕)和杂粕组2(豆粕+DDGS+葵籽粕),每个处理组3个重复,每个重复200只(公母各半)。试验期21 d。结果表明,在肉鸡平均日采食量、平均日增重、料重比、42日龄均重方面,杂粕组1与豆粕组之间,差异不显著(P0.05);平均日增重和42日龄均重方面,杂粕组2显著低于杂粕组1和豆粕组(P0.05);平均日采食量、料重比方面,杂粕组2显著高于杂粕组1和豆粕组(P0.05);成活率方面,3个处理组间无明显影响,差异不显著(P0.05)。不同蛋白质来源的饲料对肉鸡屠宰率、全净膛率、胸肌率及腿肌率均无显著影响(P0.05)。在增重饲料成本方面,杂粕组1最低,较豆粕组和杂粕组2分别降低了10美元/t,40美元/t。杂粕组1日粮可在不影响肉鸡生长性能、屠宰性能情况下,有效降低肉鸡养殖的饲料成本,提高赞比亚农场养殖效益。     

淘汰蛋鸭鸭肉品质的测定及其相关性研究

随机选取的50只日龄超过500 d的淘汰蛋鸭鸭肉为试验材料,测定其色泽、p H值、加压失水率、蒸煮损失率,剪切力等品质指标,分析探讨各指标之间的相关性。结果表明:各指标之间存在多种显著相关性,其中,同一部位鸭肉的色泽之间存在极显著的相关性(P0.01),鸭胸肉和鸭腿肉的p H值、蒸煮损失率等极显著正相关(P0.01),色泽与保水性之间呈极显著正相关(P0.01),p H值与色泽、蒸煮损失率呈显著负相关(P0.05)。故鸭肉品质之间是相互关联的,该结果能够为淘汰蛋鸭的进一步利用和鸭肉品质的综合评价与改善提供理论参考。     

质量等级对白羽肉鸡肌肉质构特性的影响

以3个不同质量等级(宰后胴体质量在1800 g~2100 g为较轻质量组,宰后质量在2100g~2400 g为中等质量组,宰后质量在2400 g~2700 g为较重质量组)的白羽肉鸡的胸肉和腿肉为实验材料,分析其质构特性的不同,并采用相关性分析方法研究不同质量等级对鸡肉质构特性的影响。结果发现随肉鸡胴体质量等级的增加,鸡胸、鸡腿肉的硬度、内聚性、咀嚼性均逐渐减小(鸡胸和鸡腿的硬度变化区间分别为2200 g~2600 g、1200 g~1800 g,内聚性变化区间分别为0.50~0.60、0.50~0.55,咀嚼性变化区间分别为850 g~950 g、400 g~800 g)。弹性先减小后增加(鸡胸和鸡腿的弹性变化区间分别为0.64~0.70、0.65~0.70),剪切力先增加后减小(鸡胸的剪切力变化区间为1500 g~2800 g)。通过相关性分析结果显示,鸡胸肉质量与硬度呈极显著的负相关(r=—0.937);鸡胸肉质量与内聚性、咀嚼性显著负相关(r=—0.826和—0.848);鸡腿肉质量与硬度显著负相关(r=—0.899);鸡腿肉质量与内聚性、咀嚼性显著负相关(r=—0.861和—0.832)。研究结果证明,白羽肉鸡生长到不同质量,其肌肉的质构特性发生变化,可以通过调控肉鸡的质量水平来调节鸡肉的质构特性。     

Classification of wooden breast myopathy in chicken pectoralis major by a standardised method and association with conventional quality assessments

Wooden breast (WB) abnormalities of broilers compromise the quality of fresh and processed meat. Yet, no standardised classification method for evaluating WB currently exists. We here provide a novel classification method to determine the severity of WB by palpation. Data were evaluated by one‐way anova . The classification method proved robust and reliable to classify broiler filets into three distinct categories (no, moderate and severe WB). This was supported by histological findings, demonstrating less muscle tissue in WB‐affected samples. Moreover, moisture content, resistance to compression, mobile water fraction, drip loss and cooking loss, as well as intramuscular and surface pH also increased with WB. Using the classification method, we demonstrated that severe WB increased the diversity of the endogenous microflora and promoted growth of Enterobacteriaceae. In conclusion, the presented classification method correlates with known meat quality traits and will be a valuable tool for future studies on WB.     

青花鸡、茶花鸡2号和白羽肉鸡肌肉脂肪酸含量比较分析

为研究青花鸡、茶花鸡2号和白羽肉鸡3 种鸡肌肉中脂肪酸含量差异,先采用氯仿-甲醇法对鸡肉粉进行脂肪提取,并对脂肪提取物进行甲酯化处理,再应用高效气相色谱仪检测3 种鸡肌肉中的18 种脂肪酸。结果表明：3 种鸡肌肉脂肪酸均以棕榈酸（C16:0）、硬脂酸（C18:0）、油酸（C18:1 n-9c）和亚油酸（C18:2 n-6c）为主;在公鸡胸肌中,青花鸡饱和脂肪酸（saturated fatty acid,SFA）含量显著高于白羽肉鸡（P＜0.05）,茶花鸡2号必需脂肪酸（essential fatty acid,EFA）含量显著高于青花鸡和白羽肉鸡（P＜0.05）;在母鸡胸肌中,青花鸡和茶花鸡2号SFA、不饱和脂肪酸（unsaturated fatty acid,UFA）含量显著高于白羽肉鸡（P＜0.05）,茶花鸡2号EFA含量显著高于白羽肉鸡和青花鸡（P＜0.05）;在公鸡腿肌中,茶花鸡2号SFA含量显著高于其他2 种鸡（P＜0.05）,茶花鸡2号和白羽肉鸡EFA、UFA含量均显著高于青花鸡（P＜0.05）;在母鸡腿肌中,青花鸡SFA含量显著高于白羽肉鸡（P＜0.05）,但与茶花鸡2号无显著差异,单不饱和脂肪酸和多不饱和脂肪酸在3 种鸡胸肌、腿肌中也有所差异。综上,不同鸡肌肉脂肪酸含量有所差异,地方资源鸡肉风味品质更佳,脂肪酸的组成更符合人体健康需求。     

Characterization of different strains of broiler chicken by carcass measurements, chemical and physical parameters and NIRS on breast muscle

The aims of the work were: to investigate the effect of chicken strain on chemical composition and colour parameters of fresh breast muscle; to evaluate the results obtained using different illuminants (A, C and F); to verify the possibility of predicting some meat features by near infrared reflectance spectroscopy (NIRS) of freeze-dried breast muscle. The trial was carried out on 39 chicken broilers from three strains, differing in body size, slaughtered at 30 days of age. Fresh breast samples were different only in ash content (P<0.01). Illuminant effect was highly significant for all colour variables, depending on the major wavelength characteristics of each illuminant. Significant differences among strains were detected in redness values. The NIRS technique was very accurate to predict fat content of muscle (R(2)c=0.98, SEC=0.20). These findings may have practical importance to improve instrumental procedures for on-line evaluation of poultry meat quality.     

A Comparison Between Two Different Shear Systems Used for Measuring Meat Tenderness

A comparison has been made between two Warner-Bratzler (WB) shear devices, differing in their method of operation, used in measuring tenderness of meat samples treated to produce a wide range, in both myofibrillar and connective tissue structural strength. Estimates of parameters measured from the shear deformation curves obtained from the two systems were highly correlated and both systems showed similar and significant responses to the treatments used to modify the structural components of meat.     

Optical scattering with hyperspectral imaging to classify longissimus dorsi muscle based on beef tenderness using multivariate modeling

The objective of this study was to develop a non-destructive method for classifying cooked-beef tenderness using hyperspectral imaging of optical scattering on fresh beef muscle tissue. A hyperspectral imaging system (λ = 922–1739 nm) was used to collect hyperspectral scattering images of the longissimus dorsi muscle (n = 472). A modified Lorentzian function was used to fit optical scattering profiles at each wavelength. After removing highly correlated parameters extracted from the Lorentzian function, principal component analysis was performed. Four principal component scores were used in a linear discriminant model to classify beef tenderness. In a validation data set (n = 118 samples), the model was able to successfully classify tough and tender samples with 83.3% and 75.0% accuracies, respectively. Presence of fat flecks did not have a significant effect on beef tenderness classification accuracy. The results demonstrate that hyperspectral imaging of optical scattering is a viable technology for beef tenderness classification.     

Fibre area and capillary supply in broiler breast muscle in relation to productivity and ascites

The objective in this study was to examine the capillary supply in the broiler breast muscle in relation to productivity and the incidence of ascites. Muscle samples (pectoralis superficialis) were collected from 24 pairs of broilers of a commercial paternal strain. The pairs consisted of full sib broilers (brothers and sisters). Of each pair one broiler had a high arterial pressure index, as an indication of ascites, and the other was a healthy chick of the same sex. Data collected were, among others, body weight, arterial pressure index, haematocrit and weight of breast muscle and lungs. Pectoral muscle samples were histologically analysed with respect to capillary density, fibre area and number of capillaries per fibre. Ascitic chickens (measured as high values for heart hypertrophy) had a lower number of capillaries per fibre and tended to have reduced fibre area, although they had a similar capillary density in the pectoral muscle in comparison with healthy chickens. The expected increase in capillary density was not observed. Normally capillary densities decrease in proportion to the increase in fibre size. So ascites has unfavourable relations with capillary traits. Fast growth was not significantly associated with capillary density. However, chickens with a higher percentage breast muscle had a lower capillary density. This implies that high muscularity might be a risk for a diminished oxygen supply to the breast muscle.     

DIFFERENTIATION OF MYOFIBRILLAR AND CONNECTIVE TISSUE STRENGTH IN BEEF MUSCLES BY WARNER-BRATZLER SHEAR PARAMETERS

Heat induced changes in aged bovine m. longissimus dorsi (LD) and m. biceps femoris (BF) were studied by water bath cooking to 60, 70 or 80°C at slow (.12°C/min) and fast (.6°C/min) heating rates. Forcedeformation curves from the Warner-Bratzler (WB) shear device were used to evaluate specific changes in the myofibrillar (WB M-force) and connective tissue component (WB C-force) of tenderness. Other measurements include WB peak force value, cooking loss, collagen solubility and sensory evaluations. Differences due to muscle type were significant in all parameters except collagen solubility. Both WB M- and WB C-force were reduced by slow heating rate but for samples heated to 80°C, WB M-force was affected only by heating rate below 60°C while WB C-force was most influenced above 60°C. Effect of final temperature resulted in higher WB M-force from 60°C to 70°C, whereas WB C-force was most affected from 70°C to 80°C. On the contrary, WB peak force was less affected by final temperature. Due to concomitant and opposing changes in myofibrillar and connective tissue strength with increasing end point temperature, it is concluded that improvements in interpretations with regard to heat-induced changes and response of heat treatment in various muscles may be increased by measurement of WB M-force and WB C-force from shear force-deformation curves.     

不同冻结方式对金鲳鱼水分、组织结构与品质变化的影响

为研究不同冻结方式对金鲳鱼水分、组织结构与品质变化的影响,本实验以鲜活金鲳鱼为原料,分别采用平板冻结（plate freezer,PF）、螺旋式冻结（spiral freezer,SF）、超低温冻结（cryogenic freezer,CF）和冰柜冻结（ordinary freezer,OF）处理样品,随后通过pH值、挥发性盐基氮（total volatile basis nitrogen,TVB-N）含量、质构特性、色泽、保水性（持水率、蒸煮损失率和汁液损失率）等指标,并结合低场核磁共振与光学显微镜观察,综合评价4 种冻结处理方式对冷冻金鲳鱼水分、组织结构与品质变化的影响。结果发现：整体而言,SF组样品的指标均优于OF组,CF组样品与SF组样品的pH值和TVB-N含量较低,其质构、色泽与保水性变化速率低于PF与OF组。由低场核磁共振结果可知,SF处理对样品水分流失影响最小。由肌肉组织微观结构观察可知,CF组与SF组样品肌原纤维间隙小、分散均匀,组织冰晶细小,金鲳鱼的综合品质较好。因此,与其他冻结方式相比,SF处理的综合效果最佳。