Prerigor Carcass Muscle Stretching Effects on Tenderness of Grain-fed Beef Under Commercial Conditions

A prerigor cut was made through the 12th thoracic vertebrae and another skeletal cut through the ischium on the pelvic bone of one side of 16 USDA Choice and 9 USDA Select beef carcasses (TC), while the companion sides served as controls (C) under industry conditions. TC lowered CIE a* values and resulted in longer sarcomeres in the longissimus muscle (LM). Compared to the C samples, the LM from TC USDA Choice carcasses were rated 28% higher (more tender) in overall tenderness and treated USDA Select carcasses were 18% higher. Also, variation in tenderness of the LM among animals was reduced by the TC Process. For Gluteus medius and Rectus femoris (RF), the TC samples were also more tender.     

Effect of Cooking Method and Ethanolic Tocopherol on Oxidative Stability and Quality of Beef Patties During Refrigerated Storage (Oxidative Stability of Cooked Patties)

ABSTRACT: Incorporation of δ-tocopherol using an ethanolic carrier to control lipid oxidation in impingement and ohmic cooked beef patties was evaluated, and quality characteristics were determined. Ethanolic δ-tocopherol delayed oxidative deterioration of cooked beef patties in both cooking methods. Ohmic cooked samples developed significantly higher ( P < 0.05) thiobarbituric acid-reactive substances (TBARS) than impingement-cooked samples. Formation of TBARS significantly ( P < 0.05) increased with storage time in both cooking treatments. Cooking method significantly ( P < 0.05) influenced color and textural attributes of beef patties. Samples cooked by ohmic heater were lighter, displaying significantly ( P < 0.05) larger L * color values. Additionally, ohmic samples were harder, chewier, and more cohesive ( P < 0.05) than samples cooked with an impingement oven. Exogenous addition of ethanolic tocopherol can delay lipid oxidation and improve quality of cooked meat products.     

Evaluation of Antioxidant Effects and Sensory Attributes of Chinese 5-Spice Ingredients in Cooked Ground Beef

ABSTRACT This study determined antioxidant and sensory characteristics of cinnamon, cloves, fennel, pepper, and star anise (Chinese 5‐spice ingredients) in cooked ground beef. Total aerobic plate counts were also measured. Mean thiobarbituric acid (TBA) values were high (3.4 ppm) for control cooked ground beef samples. With 1% use level, all spice treatments had lower pooled mean TBA values than controls. At the lowest use level of 0.1% of meat weight, all spices except pepper had lower TBA values than controls. Treatments with 0.1% cloves had lower (P < 0.05) TBA values than 0.1% levels of other individual spices. Star anise, fennel, pepper, and cinnamon samples at 0.5% use level had lower mean TBA values than controls, but not different from 1.0% levels, respectively. Thus, the lowest effective spice level for cloves was 0.1% and 0.5% for the other spices. There was a high correlation (P < 0.01) between TBA values and panel scores for rancid odor and flavor (0.83 and 0.78, respectively). Spice flavor was inversely correlated (P < 0.01) with rancid odor and flavor (‐0.57 and ‐0.61, respectively). The 5‐spice blends did not affect microbial load of cooked samples compared with controls. In conclusion, all spices and blends had a dual effect, reducing rancid odor/flavor and imparting a distinctive flavor to cooked ground beef.     

干切牛肉冻干产品的复水品质研究

将干切牛肉冻干产品复水,观察它们的形状、色泽、微观结构等变化。实验表明：复水冻干产品的形状、色泽与及微观结构与新鲜产品相比,无显著改变。气质串联色谱(GC-MS)分析表明：干切牛肉冻干复水后风味物质种类、含量变化较小;感官实验表明：冻干复水干切牛肉的口感与新鲜制品极为相似。     

Variations in Internal Color of Cooked Beef Patties

Seventeen commercially prepared patty formulations were cooked to internal temperature 71°C. Pink cooked color occurred in eight of the products and was due to incomplete denaturation of myoglobin. Although there was some relation between pH and cooked color, other factors seemed to be involved. When products were re-analyzed after 1 yr storage at -27°C, sixteen products were red/pink when cooked to 71°C. This increase in redness after frozen storage could not be explained. Cooking to internal temperatures between 81 and 87°C was necessary for complete disappearance of red/pink color. Premature browning, where a product looks well-done at temperatures lower than 71°C, occurred in one formulation.     

Ultrasonic Spectral Analysis for Beef Sensory Attributes

Ultrasonic spectral feature analysis was conducted for measuring beef sensory attributes noninvasively. Spectral features were compared with instrumental texture, chemical and sensory evaluation measures. The most significant (P <0.05) ultrasonic parameter was the number of local maxima for juiciness (ρ=0.49), connective tissue amount (ρ=0.52), flavor intensity (ρ=0.39), percent total collagen (ρ=0.34), and shear force (ρ=0.51). However, the central (resonant) frequency was the most dominant parameter for tenderness (ρ=0.45; P <0.05). Multivariate linear regression models were developed for predicting each palatability attribute. Standard errors of calibration for models were 0.253 for juiciness, 0.745 for muscle fiber tenderness, 0.244 for connective tissue amount, 0.754 for overall tenderness, and 0.224 for flavor intensity. Accuracy of prediction models was not adequate for use as a tool but this approach has potential for nondestructive sensory attribute measurement.     

Dietary α-Tocopheryl Acetate Contributes to Lipid Stability in Cooked Beef

Lipid oxidation was investigated in cooked gluteus medius from Holstein steers fed diets including four levels of α-tocopheryl acetate (0, 250, 500 and 2,000 mg/steer daily) for 42 or 126 days. Alpha-tocopherol (vitamin E) concentrations increased in fresh and cooked muscle due to level and duration of supplementation (P<0.01). Cooking did not affect α-tocopherol concentration in the muscle. Dietary α-tocopheryl acetate delayed (P<0.01) accumulation of lipid oxidation products in cooked muscle during 6 days of display at 4°. Daily supplementation of 500 mg α-tocopheryl acetate for 126 days resulted in 3.4 μg α-tocopherol/g cooked gluteus medius.     

Correlation of Sensory, Instrumental and Chemical Attributes of Beef as Influenced by Meat Structure and Oxygen Exclusion

Correlation of elements contributing to meat flavor quality (MFQ) were examined. Muscle structure influences generation of micro temperature environments that lead to formation of flavor-zones. Generation of such zones was also attributed to a structurally-dependent barrier to oxygen. MFQ was examined in the presence and absence of oxygen. Vacuum storage completely retarded flavor deterioration as marked by chemical markers such as thiobarbituric acid reactive substances and lipid volatiles. Vacuum storage incompletely affected changes in sensory attributes; it partially retarded development of painty, cardboard, bitter and sour flavors and limited loss of desirable flavors such as cooked beef/brothy and browned/caramel. Bivariate plots of factor solutions resulting from multivariate principal components analysis proved a suitable method to graphically present statistical correlations between experimental treatments and sensory, chemical, and instrumental attributes.     

Marbling, Fat Trim and Doneness Effects on Sensory Attributes, Cooking Loss and Composition of Cooked Beef Steaks

Marbling and fat trim level did not significantly affect sensory attributes of steaks. However, steaks became increasingly tougher and less juicy with increased internal end-point temperature. Cooking losses were greater for steaks with regular trim than those with total trim and increased with degree of doneness. Except for potassium, fat trim levels did not affect mineral content in cooked muscle. Intramuscular fat levels had variable effects on retention of minerals during cooking. Muscle from steaks with slight marbling had higher cholesterol levels than from those with modest marbling, but neither fat trim level nor doneness affected cholesterol content.     

油菜花黄色素在熟牛肉防腐中的应用

研究了油菜花黄色素对熟牛肉的防腐作用。实验表明,油菜花黄色素溶液浓度在0.05%以上时,对熟牛肉具有显著的防腐性,但经加热煮沸后防腐作用降低。     

Internal Premature Browning in Cooked Ground Beef Patties from High-Oxygen Modified-Atmosphere Packaging

ABSTRACT: This study examined the effects of location within a package and display time on the incidence of premature browning in patties made from ground beef packaged in a high-oxygen modified atmosphere (80% oxygen and 20% carbon dioxide) or in vacuum for up to 14 d. On days 3, 5, 8, 10, 12, and 14 of display, patties were formed from both top and bottom portions of tissue exposed to high-oxygen. These patties contained predominantly oxymyoglobin and metmyoglobin at the time of formation and cooking. As display progressed, the percentage of oxymyoglobin decreased ( P < 0.05) and metmyoglobin increased ( P < 0.05) in the patties for both locations, whereas the percentage of deoxymyoglobin remained stable at less than 2%. Samples that were vacuum-packaged contained predominantly deoxymyoglobin. Patties from high-oxygen packages cooked to a temperature of 71.1 °C were prematurely brown ( P < 0.05) compared with vacuum-packaged samples. Patties containing predominantly deoxymyoglobin remained pinker than patties cooked directly from high-oxygen packages (lower visual color score, higher a * value; P < 0.05) on the interior after cooking. Data in this study clearly demonstrate that, regardless of time in display, nearly 100% of patties formed from high-oxygen-packaged ground beef would be prematurely brown when cooked and could pose a food safety problem if not cooked to an endpoint temperature ensuring safety.     

Muscle Microstructure and Sensory Attributes of Organic Acid-Treated Beef Strip Loins

Beef strip loins were cut into halves and one-half sprayed with a 2% lactic and acetic acid mixture (v/v) and corresponding halves used as controls. Strip loins were stored at – 1°C for 0, 7, 14, 28, 56, 84, or 112 days and evaluated for sensory and microstructural properties. Cooking loss and Hunter color ‘L’ values decreased (P<0.01) and thiobarbituric acid reactive substances (TBARS) increased (P<0.01) over 112 days. No differences (P>0.05) were detected for cooking loss, shear force, TBARS, or Hunter color values between treatments. Flavor intensity increased (P<0.05) over time; however, no other sensory differences (P>0.05) were noted for storage time or acid treatment. Organic acids appeared to denature muscle microstructure without having any effects on physical and sensory attributes.     

消费者对重组调理牛排态度的调查研究

近年来,国内肉类企业不断加大重组调理牛排的生产量,但是关于消费者对重组调理牛排的态度鲜有报 道。本研究通过网络调研与实地调研相结合的方法调研我国消费者对重组调理牛排的认知与态度。结果表明：产品 质量是消费者购买重组调理牛排的首要考虑因素;相比于其他购买方式,消费者更愿意在超市等实体店购买重组调 理牛排;月收入6 000 元以下的消费者更倾向于购买重组调理牛排,重组调理牛排的市场定位应为中低端产品。     

熟制牛肉肉色问题和影响因素研究进展

近年来,我国消费者尤其是逐渐扩大的中产阶级群体对牛排、牛肉饼、汉堡包、烧烤牛肉等西式牛肉制品的消费越来越多,对牛肉品质和安全的要求也越来越高,但是该类牛肉制品熟制过程中存在一些肉色问题。本文综述了牛肉加热过程中常见的肉色问题,包括未完成熟制前肉色提前褐变现象、达到熟制温度后肉色仍然呈现粉红现象和熟制结束后肉色恢复红色的现象;分别阐述了其产生机制、主要影响因素和相关控制措施,概括了影响熟制牛肉肉色的主要因素,并对熟制牛肉肉色问题产生的分子机制研究提出展望,以期为我国熟制牛肉肉色的控制提供思路。     

Thawing Prior to Cooking Affects Sensory, Shear Force, and Cooking Properties of Beef Patties

Patties from 6 commercial formulations were cooked to 71°C from either the frozen state or after thawing for 24 to 27 h at 4 °C to eliminate the pink/red color exhibited when cooked to 71 °C from the frozen state. Thawed patties had shorter cooking times, higher cooking yields, and lower shear force peak load and peak energy values. Patties cooked from the thawed state increased in thickness during cooking, while patties cooked from the frozen state decreased in thickness during cooking. Thawing prior to cooking increased sensory evaluation scores except for patties made with carrageenan. Thawing not only eliminated the problem of pink/red color after cooking but also improved sensory, shear force, and cooking properties of beef patties.     

Internal Premature Browning in Cooked Steaks from Enhanced Beef Round Muscles Packaged in High-oxygen and Ultra-low Oxygen Modified Atmospheres

ABSTRACT: Beef round muscles were injection-enhanced to 6%, packaged in high-oxygen (HiOx) or ultra-low oxygen (LoOx) modified atmospheres, stored 7 d and displayed 2 d (HiOx) or stored 16 d and displayed 1 d (LoOx) at 0 °C, and cooked to 71.1 °C. Raw internal color for steaks in HiOx was lighter, redder, more yellow and saturated, and had more oxymyoglobin and less deoxymyoglobin than steaks in LoOx ( P < 0.0001). Cooked internal color of steaks from HiOx appeared prematurely brown and was darker, less red, yellow, and saturated, and had more denatured myoglobin than steaks from LoOx ( P < 0.0001). This study presents conclusive evidence that modified-atmosphere packaging influences internal cooked color development of beef steaks.     

高光谱成像技术定量可视化检测熟牛肉中挥发性盐基氮的含量

为了能够快速、准确的检测出熟牛肉在冷藏过程中的新鲜状况,尝试利用高光谱成像技术对熟牛肉中的挥发性盐基氮(TVB-N)含量进行定量可视化分析。采集400~1000 nm范围内样品高光谱图像,采用变量组合集群分析法(VCPA)提取出6个光谱特征波段变量,针对特征波段图像,利用Tamura算法共提取出18个纹理特征变量,基于RGB颜色模型,分别计算出R、G和B分量图中共9个颜色特征变量。利用粒子群优化最小二乘支持向量机(PSO-LS-SVM)算法分别建立了不同变量组合的TVB-N含量预测模型。经分析比较,基于光谱与颜色特征融合的PSO-LS-SVM模型展现出最优的预测能力,预测集决定系数(R2p)和均方根误差(RMSEP)分别为0.955和1.093。利用最优模型将TVB-N含量进行可视化表达。结果表明,融合高光谱图像中光谱与颜色特征并结合PSO-LS-SVM算法对熟牛肉中TVB-N含量进行准确的预测与可视化表达是可行的,该研究可为其它肉及肉制品新鲜度检测提供理论参考。     

Antioxidative Activity of Maillard Reaction Products in Cooked Ground Beef, Sensory and TBA Values

Maillard reaction products (MRPs) obtained by autoclaving egg albumin acid hydrolysate and glucose for 1 hr were added to ground beef which was cooked and stored at 4°C for 8 days. The antioxidative activity of MRPs was investigated by a trained sensory panel and the TBA test. The panel evaluated samples for loss of desirable cooked beef notes and generation of off-flavors, such as cardboard and painty. With added 1% MRPs, painty aroma and flavor scores were low and did not (p > 0.05) change over time. The coefficients of determination were high (r²= 0.92 to 0.77, p < 0.0001) between aroma and flavor scores for any two similar attributes. The TBA values decreased by 17% with the addition of 0.5% MRP and by 39% with 1% MRP over time.     

Cooked Color in High pH Beef Patties as Related to Fat Content and Cooking from the Frozen or Thawed State

Beef patties were processed from high pH (>6.0) beef to contain 5, 10, 15, 20 or 25% fat. Patties were cooked to 71°C from the frozen or thawed state before evaluating color. Neither fat content nor state of patties when cooked exerted any major influence on color, but linear effects (p<0.01) in association with increased fat content included higher L* values and hue angles and lower a* values (15.2% reduction). Higher values for L*, b* (but not for 5% fat patties), and hue angles were observed for patties cooked thawed rather than frozen. The use of high pH beef lessened the effects of increased fat and cooking from the thawed state on increased brown color in cooked patties.