Iron Distribution in Heated Beef and Chicken Muscles

Distribution of iron in six fractions (water-soluble, water-insoluble, diffusate, hematin, total heme, and ferritin) of beef and chicken muscles hcatcd to 55, 70, 85, and 100°C was determined. Iron content decreased in water-soluble fractions and increased in water-insoluble fractions as temperature increased from 27°C to 100°C. Heme iron decreased more from 55°C to 85°C than from 27°C to 55°C or 85°C to 100°C. The increase in diffusate iron appeared to be less than the decrease in heme iron at each heating temperature. As temperature increased from 27°C to 100°C, hematin iron content increased and extractable ferritin iron content decreased. These findings may help explain rapid development of oxidative rancidity in cooked meat.     

Characterization of the Muscles within the Beef Forequarter

Thirty-four muscles/muscle groups, each 0.1 kg or greater, were dissected from each of 16 forequarters to establish a data base of individual muscle traits. Individual muscle yields, tenderness profiles, and chemical analyses indicated the muscles within the forequarter are extremely variable. The Serratus ventralis (SRV), Infraspinatus (INF) and Triceps brachii complex (lateral, long and medial heads, TBT, TBL and TBM, respectively), which are several of the larger muscles/muscle groups within the forequarter, possess tenderness profiles comparable to the Longissimus dorsi (LGD). This study suggests that maximum utilization of the beef forequarter may best be achieved when individual muscles are fabricated and marketed according to their size, tenderness potential and composition.     

Hematological Status of Rats Fed Oxidized Beef Lipids

Hemoglobin, hematocrit, total iron binding capacity, and erythrocyte thiobarbituric acid (TBA) numbers were measured in blood from rats given a diet containing 52.7% cooked ground beef which was fed as freshly cooked beef (control), or after refrigerated storage (5°C) for 1, 3 or 8 days. Rats were maintained on the experimental diets for 6 wk. As the level of oxidation increased in the meat, erythrocyte TBA numbers also increased and were significantly different among groups. There was a drop in the erythrocyte TBA numbers for rats consuming beef stored for 8 days, suggesting that a level of rancidity was reached that was adequate to induce synthesis of enzymes that metabolize free radicals such as catalase, glutathione peroxidase, and superoxide dismutase.     

Chemical and Sensory Properties of Thirteen Major Beef Muscles

Chemical and sensory properties of the following thirteen muscles from ten Angus steers were evaluated: semimembranosus, semitendinosus, adductor, biceps femoris, rectus femoris, gluteus medius, psoas major, longissimus - loin portion (LD-L), longissimus - rib portion (LD-R), triceps, infraspinatus, pectoral, and supraspinatus. Steaks (3.8 cm) were cooked to 70°C internally on open hearth grills for sensory evaluation. Muscles from the round and chuck, excluding the infraspinatus, were generally scored lower by the sensory panel than muscles from the loin and rib. The psoas major, LD-L, LD-R, and infraspinatus were more tender (P < 0.05) than seven other muscles; WBS values followed the same trend. Large ranges were observed among muscles for percent fat, sarcomere length, and total collagen.     

宰后成熟对牛胴体不同部位显微结构影响

将不同部位肉样真空包装后于4℃条件下成熟72h ,采用石蜡切片苏木精-伊红(HE)染色法、原子力显微镜扫描肌原纤维、环境扫描电镜扫描肌纤维膜、免疫组织化学法及测定剪切力,研究牛胴体不同部位剪切力、宰后成熟过程中肌纤维和肌原纤维裂解程度、肌纤维膜变化及μ-calpain肌纤维定位。结果表明：剪切力：半腱肌＞腹直肌＞背最长肌;牛肉后熟过程中,背最长肌肌纤维、肌原纤维裂解程度最大,腹直肌次之,半腱肌变化较小;肌纤维膜变化不大;μ-calpain主要存在于肌纤维膜和肌浆中,红肌纤维(慢肌)μ-calpain含量高,白肌纤维(快肌)μ-calpain含量低。μ-calpain在牛肉后熟过程中对牛肉嫩化具有重要作用,红肌纤维μ-calpain含量高,白肌纤维μ-calpain含量低,因此,胴体不同部位红肌纤维和白肌纤维的比例是导致其后熟嫩度和显微结构差异较大的一个重要因素。     

Nutrient Composition of Muscles in Deer and Boar

In trimmed muscle types of four game species the dry matter, crude protein, crude fat, ash, Ca, P, Mg, Na, K, Cu, Zn, Fe, and Mn contents were determined. Samples of the m. semimembranosus and m. longissimus dorsi of each of 10 red deer, fallow deer, roe-deer and wild boars from the Southwestern region of Hungary in the end-winter period were analyzed, and mean values, related to dry matter, were compared. The game muscle samples had much lower crude fat, more Ca, P and microelements, especially Cu and Fe, when compared with published data for the respective muscles of domestic animals.     

去骨方法对牛肉和火鸡肉化学成分及一些特性的影响

本文针对机械去骨和人工去骨的牛肉以及火鸡肉的一些化学、物理特性进行了对比研究。相近成分胆固醇、硫代巴比土酸(TBA)、钙铁含量、颜色参数、脂肪酸成分等指标在样本中得以分析。去骨方法对牛肉和火鸡肉的化学成分有所影响。机械去骨导致较高的胆固醇以及钙铁含量。在手工去骨火鸡肉中,含量最多的脂肪酸是C16:0、C18:1以及C18:2。机械去骨加工使火鸡肉中C18:1、C18:2、C18:3的含量增加。而C16:0、C18:0、C18:1则是机械去骨和手工去骨牛肉中主要的脂肪酸。     

Effect of Animal Age on the Tenderness of Selected Beef Muscles

The tenderness of 12 beef muscles from animals of 8 different age groups (ranging from 1 to about 60 months old) which were treated to minimize pre-rigor myofibrillar shortening, have been assessed using objective and subjective methods. The mean tenderness of these 12 muscles significantly (p<0.001) decreased with age. The rate of increase in the toughness of individual muscles with animal age was related to their connective tissue strength. Psoas major muscles were almost unaffected by increasing animal age whereas high connective tissue strength muscles, such as the Biceps femoris, trebled in toughness. A comparison of the different muscles revealed that one of the least representative was the often used M. longissimus dorsi.     

A Sensory Panel and Chemical Analysis of Certain Beef Chuck Muscles

Sensory panel and Warner-Bratzler Shear (WBS) values of nine muscles (biceps brachii, complexus, deep pectoral, infraspinatus, longissimus, rhomboideus, serratus ventralis, supraspinatus and triceps brachii) from the beef chuck. The deep pectoral, infraspinatus and rhomboideus were used to determine myofibril fragmentation index (MFI), and the infraspinatus and rhomboideus were used to study myofibrillar protein degradation. The infraspinatus was scored the most tender and palatable, and the rhomboideus was scored least tender and palatable. Greater protein degradation differences were observed in myofibrils isolated from the infraspinatus muscle than in those from the rhomboideus for the proteins titin, nebulin and troponin-T.     

Content of Zinc in Selected Muscles from Beef, Pork, and Lamb

Zinc concentration was measured in four muscles from beef, pork, and lamb: longissimus dorsi (LD), biceps femoris (BF), gluteus medius (GM), and triceps brachi (TB). Within a species, BF, GM, and LD had similar zinc concentrations but TB was significantly (P<0.01) higher in zinc. The means for the four muscles ranged from 39.8–53.5, 13.9–28.0, and 28.2–36.9 μg Zn/g wet weight for beef, pork, and lamb, respectively. The zinc concentration of muscle may relate to protein synthesis and the predominant type of energy metabolism occurring in the muscle. The mean zinc concentration of the four muscles between species was significantly (P< 0.01) different.     

Composition of Surimi-like Material from Beef or Pork

A surimi-like material was made from finely minced beef or pork by water washing followed by screening to remove connective tissue. Changes in component proteins, amino acid composition and vitamin, mineral and cholesterol content occurring during preparation were investigated. Total amino acid nitrogen contents of water-washed beef and pork were higher than those of the respective muscle by 7% and 6.5%. Among 16 amino acids measured, histidine and glycine decreased in both water-washed beef and pork, while others increased compared to original muscle. Thiamin content decreased after washing. Surimi-like beef and pork had less cytoplasmic minerals (K, Na, Mg) but more minerals associated with proteins or subcellular organelles (Ca, Cu, Zn, Fe). Fat content decreased, although cholesterol concentration was not changed by washing.     

Tenderness Improvement of the Major Muscles of the Beef Carcass by Electrical Stimulation

Steaks (arm; blade; seven-bone; rib, small-end; top loin; tenderloin; top sirloin; tip, cap-off; and round) from electrically stimulated (ES) and control sides of 20 beef carcasses were cut and frozen at 5 days postmortem. Forequarter muscles that were improved by ES were the longissimus dorsi (rib steak), the subscapularis and supraspinatus (blade steak), and the superficial pectoral (arm steak). Hindquarter muscles that were improved by ES were the longissimus dorsi (top loin steak), the biceps femoris and gluteus medius (top sirloin steak), and the semimembranosus and biceps femoris (round steak). ES, in addition to improving tenderness of the longissimus dorsi, increased tenderness of other major muscles in the carcass.     

Composition and Chemistry of Mechanically Recovered Beef Neck-Bone Lean

The objective was to characterize basic chemical and functional differences among mechanically recovered neck-bone lean beef (MRNL), hand-trimmed neck-bone lean beef, a control of 85% beef lean trim and bone marrow. MRNL had higher (P < 0.05) metmyoglobin reducing ability and more total iron than the control and more fat (P < 0.05) than hand trim. Values for pH were higher (P < 0.05) for MRNL than for hand trim or the control (6.68, 6.33 and 5.80, respectively). MRNL also had higher (P < 0.05) nonheme iron, total pigment and water-holding capacity. Bone marrow had higher (P < 0.05) ash, cholesterol, total iron, total pigment and pH than any lean types.