The effect of muscle, cooking method and final internal temperature on quality parameters of beef roast

The aim of the study was to evaluate the influence of cooking conditions (dry air and steam) and final internal temperature (75, 85, 95°C) on the physico-chemical properties of beef infraspinatus (INF) and semimembranosus (SEM) muscles as well as their tenderness and juiciness. Cooking method and temperature influenced moisture, total collagen content in cooked meat and cooking loss, whereas muscle type affected fat, total collagen content and cooking loss. Warner-Bratzler shear force values were affected by cooking method, which also influenced juiciness of roasts. Temperature affected tenderness and juiciness, whereas muscle type influenced juiciness. The most desirable tenderness had INF heated in steam and dry air to 95°C. Processing SEM in dry air to 85 and 95°C lowered the juiciness of the roasts. There were significant correlations between physico-chemical, sensorial and image attributes, however high accuracy of prediction (r(2)>0.8) was achieved only for SEM muscle.     

Tenderness of pre- and post rigor lamb longissimus muscle

Lamb longissimus muscle (n=6) sections were cooked at different times post mortem (prerigor, at rigor, 1dayp.m., and 7 days p.m.) using two cooking methods. Using a boiling waterbath, samples were either cooked to a core temperature of 70 °C or boiled for 3h. The latter method was meant to reflect the traditional cooking method employed in countries where preparation of prerigor meat is practiced. The time postmortem at which the meat was prepared had a large effect on the tenderness (shear force) of the meat (P<0.01). Cooking prerigor and at rigor meat to 70 °C resulted in higher shear force values than their post rigor counterparts at 1 and 7 days p.m. (9.4 and 9.6 vs. 7.2 and 3.7 kg, respectively). The differences in tenderness between the treatment groups could be largely explained by a difference in contraction status of the meat after cooking and the effect of ageing on tenderness. Cooking pre and at rigor meat resulted in severe muscle contraction as evidenced by the differences in sarcomere length of the cooked samples. Mean sarcomere lengths in the pre and at rigor samples ranged from 1.05 to 1.20 μm. The mean sarcomere length in the post rigor samples was 1.44 μm. Cooking for 3 h at 100 °C did improve the tenderness of pre and at rigor prepared meat as compared to cooking to 70 °C, but not to the extent that ageing did. It is concluded that additional intervention methods are needed to improve the tenderness of prerigor cooked meat.     

Extended shelf-life of unrefrigerated prerigor cooked meat

Five experiments were conducted to evaluate the microbial quality of unrefrigerated cooked prerigor beef after the application of oxygen-permeable packaging. Specific objectives were to combine the beneficial effects of aerobic packaging, meat surface acidification and prerigor rapid cooking rates on meat storage stability at ambient temperature. In the experiments, the triceps brachii muscle was dissected from one side 45 min after exanguination of the animal, and samples of 2 × 3 × 5 cm were prepared. Bags made of a strong barrier, plastic film, and a highly oxygen permeable oriented polypropylene, were used. The cooking of the packaged samples covered a number of treatments ranging from cooking in a 70°C water bath to an internal sample temperature of 65°C to cooking in 100°C water for 40 min. Reheating and multiple heat treatments were also included. The pH values of the cooked samples were determined and aerobic plate counts (log(10)/g) were determined for the cooked samples at various intervals during two weeks of storage at 22°C or at 3°C for the control samples. The results indicate that heat treatment alone did not improve shelf stability at 22°C. However, dipping the samples in 80°C solutions of 0·7% citric acid or 1·25% lactic acid for 1 min and draining for 1 min followed by packaging using oxygen permeable bags and cooking in 100°C water for 40 min consistently resulted in shelf stable products at all 22°C storage intervals. The lactic acid treatment was superior to the citric acid treatment because it completely decontaminated the samples and delayed spoilage, especially at 3°C.     

Quality and proteome changes of beef M.longissimus dorsi cooked using a water bath and ohmic heating process

This study investigated the effects of different cooking methods, namely water bath cooking (WB), short time ohmic cooking (STOH) and long time ohmic cooking (LTOH) on color, cooking loss, shear force value and proteome changes in beef M.longissimus dorsi at the same endpoint temperature of 72 °C. The cooking loss and shear force value of the ohmically cooked meat were significantly lower (P < 0.05) and redness a* value was significantly higher than that of the WB cooked samples. Proteomics analysis showed that ohmically cooked meat had less protein damage than those of WB cooked ones. Seventeen protein spots of differential abundance in two-dimensional gel electrophoresis (2-DE) image between STOH and WB cooked samples were successfully identified, and thirteen protein spots between LTOH and WB cooked samples were identified. Most of them belong to myofibrillar and sarcoplasmic proteins and may be related to changes of meat quality parameters.Industrial relevanceDuring thermal processing, proteins, the primary constituents of meat, undergo structural modifications such as oxidation, degradation, denaturation and aggregation. These changes of proteins have important effects on the quality of the final meat products, such as color, tenderness and flavor, and ultimately affect meat palatability and acceptability. Nowadays, innovation is necessary in developing new cooking methods to meet the industrial demand for more efficient production and consumer's demand for higher quality and safer meat products. Ohmic cooking, also known as electric resistance cooking, relies on the heat that is generated when electrical current passes directly through conductive foodstuff to cook the food. Compared to conventional cooking, ohmic cooking has the advantages of much shorter cooking time, higher yield and more uniform heating distribution, and ohmically cooked meat has superior color, higher tenderness, etc. Therefore, as a potential food processing technology, ohmic heating not only increases energy efficiency, but also improves meat quality. In this study, two-dimensional gel electrophoresis and tandem mass spectrometry were used to investigate the quality and proteome changes of beef M.longissimus dorsi following ohmic cooking and water bath cooking, and the results indicated that protein damages in ohmically cooked meat were much less than that of water bath cooked ones, and this might contribute to the lower cooking loss, higher tenderness and better color in ohmically cooked meat. The results of the study suggested that ohmic cooking has a great potential in industrial production of meat products.     

氢氧化铵处理对牦牛肉理化性质的影响

以牦牛肉为研究对象,研究了不同氢氧化铵添加量对牦牛肉的pH值、嫩度、胶原蛋白溶解性、离心损失和蒸煮得率的影响,以及滚揉处理的协同作用.结果表明:添加一定量的氢氧化铵可以显著的提高牦牛肉的pH值、蒸煮得率和胶原蛋白溶解性,降低离心损失和剪切力值,而滚揉处理可以显著促进氢氧化铵对牦牛肉的嫩化作用.     

Influence of cooking conditions on cooking loss and tenderness of raw and marinated chicken breast meat

The influence of different cooking treatments on tenderness and cooking loss, as main quality characteristics of chicken breast meat, was investigated. Industrial skinless chicken breast meat samples were designated as raw and marinated and cooked in the oven by hot air and hot air-steam mixture at 130, 150 and 170 °C, for 4, 8 and 12 min. Cooking losses were evaluated by weight changes before and after cooking, and tenderness changes were determined on cooked samples by measuring shear force using instrumental texture analysis. Results showed that marination, followed by air-steam cooking is the best combination to obtain the most tender chicken breast slices. The time and temperature of cooking showed similar effects on cooking loss and tenderness: short cooking time (4 min) and temperatures of 130–150 °C resulted in lower cooking losses and best meat tenderness, in both not marinated and marinated meat. Statistically significant correlations between tenderness and cooking loss indicated that the cooking loss correlated better with cooking time than with cooking temperature. An opposite phenomenon was observed for meat tenderness.     

Changes in Shear Parameters,Protein Degradation and Ultrastructure of Pork Following Water Bath and Ohmic Cooking

The objective of this study was to investigate the effects of ohmic (OH) and water bath (WB) cooking on shear parameters, protein degradation and ultrastructure changes of porcine longissimus dorsi muscle at the same endpoint temperatures (EPTs; range, 20–100 °C). The cooking loss and Warner–Bratzler shear force of the OH-cooked meat were significantly lower (P?<?0.05) while protein solubility, pH and endothermic transition temperature were higher than those obtained by WB cooking at the same EPTs (range, 20–80 °C). Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis showed that during OH cooking, the meat had slightly fainter protein bands than that of WB-cooked ones. Less obvious shrinkage of the sarcomere and loss in the structure of Z discs were detected especially in OH-cooked meat at EPTs (100 °C). Strong correlations among pH, cooking loss, Warner–Bratzler shear force, sarcoplasmic protein solubility, T _max2, and T _max3 were observed in meat following OH cooking.     

Effect of post-mortem conditioning of ewe carcasses on instrumental texture profile of cooked thigh muscles

The semimembranosus (SM) and semitendinosus (ST) muscles were removed from 18 four to five year old Bannur breed ewes which were slaughtered and carcasses (six each) suspended by the (a) Achilles tendon at 26 ± 2°C for 1 h before cutting (b) Achilles tendon at 2-3°C for 42 h and (c) Pelvis at 26 ± 2°C for 7 h followed by chilling at 2-3°C for 17 h. The muscles were cooked by boiling in a water bath for 30 min or by heating in a pressure cooker for 20 min and the tenderness measured with a Warner-Bratzler tenderometer. Hardness, cohensiveness, elasticity and chewiness were also measured with a General Foods Texturometer. With conventional hanging at 2-3°C the SM muscle was the toughest and the ST muscle the most tender. By holding carcasses at 26 ± °C for 1 h before cooking there was an increased tenderness. The most tender meat was found from carcasses which were suspended by the pelvis at 26 ± °C before chilling. The increase or decrease in shear values were respectively associated with contraction or stretching of muscles effected by carcass conditioning treatments. In contrast, thermal shrinkage due to cooking had opposite effects so that greater thermal shrinkage resulted in lower shear values. The shear values from the Warner-Bratzler tenderometer did not correlate well with the parameters measured by the General Foods Texturometer.     

超高压处理对牛肉主要理化品质的影响

探讨超高压处理(不同压力和保压时间)对牛肉主要理化品质的影响。牛半腱肌肉经200～600MPa压力分别处理10min和20min,分析胶原蛋白含量和溶解性等特性以及牛肉蒸煮损失和嫩度在超高压处理过程中的变化。结果表明：随着压力的升高,牛半腱肌肉的剪切力均呈下降趋势,保压时间为20min时剪切力下降更显著。当压力达600MPa,牛肉剪切力分别降至39.59N(保压10min)和31.36N(保压20min)。总胶原蛋白、可溶性胶原蛋白的含量和胶原蛋白的溶解性随着处理压力的升高而增加。胶原蛋白特性变化与肉品质之间存在显著相关性。     

The Effects of Marination and Cooking Regimes on the Waterbinding Properties and Tenderness of Beef and Bison Top Round Roasts

ABSTRACT: The combined effect of marination and different cooking regimes on the cooking yield and palat-ability of bison and beef top round roasts was investigated. Semimembranosus (SM) muscles from beef and bison top rounds were injected with a marinade to achieve 20% extension by weight and 0.5% sodium chloride and 0.3% sodium tripolyphosphate levels and then subdivided into 4 roasts and cooked by following 4 cooking regimes: cooking at a constant temperature of 75°C (control; C); similar to the control treatment except that roasts were held at an internal temperature of 55°C for 45 min (Hold45) or 90 min (Hold90) prior to final cooking at 75°C; initial cooking at 55°C with a 5°C increase in oven temperature every hour (Step-up) until the 71°C internal temperature was achieved. Cooking yield, expressible moisture, purge, and shear force of processed roasts were determined. Marination by injection improved the yield and tenderness of beef and bison SM roasts. The cooking yield for injected samples (78%) was significantly (P < 0.05) higher compared with noninjected controls (68%). Injected SM roasts from bison had lower cooking losses than those from beef, whereas control samples from these 2 species did not differ in their cooking yields. Injected beef SM was more tender than bison SM; however, marination significantly reduced the shear force values of SM roasts for both species (i.e., shear force values of 82 N in control samples was reduced to 63 N in injected ones). The cooking regimes, Hold45, Hold90, and Step-up (which allowed a longer time at 55 to 60°C), gave products with lower ( P < 0.05) shear force values than those of the controls. Based on the cooking yield and time involved, the Hold 45 treatment performed the best.     

Observations on some chemical and physical characteristics of buffalo meat

Proximate composition, sarcoplasmic and myofibrillar protein fractions of buffalo meat were similar to those of beef. Buffalo meat was also rich in lysine. Meat from young animals had a lower collagen content than that from old ones. As the temperature of holding the carcasses was increased, the rate of pH fall was faster. Meat from stressed animals showed a higher ultimate pH. Percentage of cooking loss and thermal shrinkage was higher in muscles of old animals than in young ones, which probably reflected the poor condition of the older animals. Meat cooked by pressure cooking showed lower Warner-Bratzler shear values as compared with meat cooked in boiling water.     

High and low rigor temperature effects on sheep meat tenderness and ageing

Immediately after electrical stimulation, the paired m. longissimus thoracis et lumborum (LT) of 40 sheep were boned out and wrapped tightly with a polyethylene cling film. One of the paired LT's was chilled in 15°C air to reach a rigor mortis (rigor) temperature of 18°C and the other side was placed in a water bath at 35°C and achieved rigor at this temperature. Wrapping reduced rigor shortening and mimicked meat left on the carcass. After rigor, the meat was aged at 15°C for 0, 8, 26 and 72 h and then frozen. The frozen meat was cooked to 75°C in an 85°C water bath and shear force values obtained from a 1×1 cm cross-section. The shear force values of meat for 18 and 35°C rigor were similar at zero ageing, but as ageing progressed, the 18 rigor meat aged faster and became more tender than meat that went into rigor at 35°C (P<0.001). The mean sarcomere length values of meat samples for 18 and 35°C rigor at each ageing time were significantly different (P<0.001), the samples at 35°C being shorter. When the short sarcomere length values and corresponding shear force values were removed for further data analysis, the shear force values for the 35°C rigor were still significantly greater. Thus the toughness of 35°C meat was not a consequence of muscle shortening and appears to be due to both a faster rate of tenderisation and the meat tenderising to a greater extent at the lower temperature. The cook loss at 35°C rigor (30.5%) was greater than that at 18°C rigor (28.4%) (P<0.01) and the colour Hunter L values were higher at 35°C (P<0.01) compared with 18°C, but there were no significant differences in a or b values.     

Analysis of Warner-Bratzler shear pattern with regard to myofibrillar and connective tissue components of tenderness

Force-deformation 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 in samples from beef semitendinos. Cores were heated in a water bath to end point temperatures of 60°C and 80°C by using combinations of slow and fast heating rates. Increasing the end point temperature from 60°C to 80°C was found to increase the WB M-force and to decrease the WB C-force, whereas the WB peak force was least affected. Comparisons between different heating rate combinations to samples heated to 80°C showed that the WB M-force was affected by a heating rate both below and above 60°C, while the WB C-force was most influenced by a heating rate above 60°C. Slower heating rates and higher endpoint temperatures resulted in greater cooking losses and increased solubility of collagen. The WB M-force and WB C-force were found to be more significant estimators of sensory evaluations of tenderness and collagen solubility in this experiment than the usually measured WB peak force.     

Modelling the effect of sarcomere length on collagen thermal shortening in cooked meat: consequence on meat toughness

Normal and contracted pieces of Semimembranosus and Longissimus Dorsi muscles from cull cows were cooked for 90 min at temperatures up to 80°C. For both muscles, at 50°C the normal samples have higher breaking stress than contracted samples. The breaking stress of normal samples decreases at 55°C. This decrease is not observed for contracted samples. The contracted samples become the tougher above 60°C. Drip and cooking losses are the highest in contracted samples. Sarcomere length decreases above 60°C whatever the raw sarcomere length. The amplitude of thermal shortening of perimysium collagen fibres in cooked meat has been calculated. This theoretical model takes into account the changes in the waviness of collagen fibres associated with changes in raw sarcomere length and the geometrical changes of fibre bundles due to drip, cooking losses and cooking shortening. The calculations lead to the conclusion that thermal shortening of collagen fibres at 60°C is lower in contracted samples than in normal samples. As the final modulus of collagen fibres decreases when their thermal shortening increases, this can explain part of the differences observed between the toughness of normal and contracted cooked meats. In particular, it can explain why contracted cooked meat becomes tougher than normal meat just above 60°C and why there is a decrease in normal meat toughness between 55 and 60°C. This work therefore emphasises the role of collagen in toughening associated with cold shortening.     

Effect of cooking temperature and cooking time on Warner-Bratzler tenderness measurement and collagen content in rabbit meat

The effects of cooking temperature (50-90?°C) and time (10-120 min) on Warner-Bratzler (WB) tenderness measurement of longissimus lumborum (LL) muscle in 70-day-old rabbits were investigated. Cooking losses, total collagen content and collagen solubility of LL muscle were measured in parallel. Increasing cooking temperature caused a four-phase effect on WB measurement. Stress and total energy were significantly increased between raw meat and cooked meat at 50?°C, then they dramatically decreased to a minimum observed at 60-65?°C, and increased again to reach a maximum at 80-90?°C. Cooking losses exhibited an 83% increase between 50 and 80?°C. At 80?°C, stress and total energy values remained constant after 20 and 40 min respectively. LL muscle collagen content was 16.4±2.3 mg/g of dried muscle. Collagen solubility at 77?°C for 1 h was high: 75.3±8.1%.     

Effect of freezing temperature, thawing and cooking rate on water distribution in two pork qualities

The effects of freezing temperature (-20 versus -80°C) in combination with long-term freezer storage (-20°C) on water mobility and distribution in pork of two qualities (normal and high ultimate pH) were explored using low-field NMR T(2) relaxometry. A marked effect of freezing temperature on the characteristics of intra- and extramyofibrillar water (T(2) relaxation times) in the thawed pork was demonstrated, implying that the freezing temperature in combination with prolonged freezer storage affects the distribution and chemical-physical state of water in the thawed meat. Determination of technological properties (thawing and cooking loss) revealed that the observed T(2) variations related to water distribution and water properties, which were found to be consistent with the degree of structural damage assessed by light microscopy, also were reflected in the technological quality of the meat. Low freezing temperature in combination with prolonged freezer storage was associated with increased thawing and cooking loss. In addition, pH in the fresh meat had a pronounced effect on the distribution of myofibrillar water, as a more homogenous pore size distribution was evident in meat with high pH compared with normal pH. A clear effect of cooking rate on the T(2) relaxation characteristics in the cooked pork was also demonstrated, probably reflecting a cooking rate-induced effect on the myofibrillar structures. The effect of cooking rate on water distribution resulted in a significantly lower cooking loss upon a slow cooking rate (0.5°C/min from 25 to 65°C and 0.3°C/min from 65 to 80°C) compared with a fast cooking rate (1°C/min).     

Effect of prolonged heat treatment from 48 °C to 63 °C on toughness, cooking loss and color of pork

The effect of low temperature long time (LTLT) heat treatment at 48 °C, 53 °C, 58 °C, and 63 °C for T(c) (time to reach a core temperature equal to the water bath), T(c)+5h holding time, and T(c)+17h holding time was studied in Longissimus dorsi and Semitendinosus muscles from slaughter pigs and sows. Meat toughness (Warner-Bratzler Shear Force), cooking loss and color (Minolta L*a*b*-values) was measured and in the cooking loss the amount of heat-soluble collagen and activity of cathepsin B+L was determined. Decreasing shear force and increasing cooking loss during LTLT treatment was observed between 53 °C and 58 °C. Furthermore, increasing temperature from 53 °C to 58 °C and increasing time from T(c) to T(c)+17h increased the solubility of collagen. Residual activity of cathepsin B+L in LTLT treated pork was mainly affected by temperature, showing the highest activity at 58 °C and 63 °C.     

Effect of method of cooking on identification of heat processed beef using polymerase chain reaction (PCR) technique

Effects of various cooking methods including boiling, roasting, pressure cooking, and pan frying on species determination of beef by PCR was studied. The meat was cooked by boiling at 97.5°C for 140, 200 or 230min, by roasting at 200°C for 80, 120, or 150min or by autoclaving at 120°C for 30, 60, or 90min. The beef sample was pan fried until the meat was acceptable for sensory attributes (45min, meat temperature 115°C, fat temp 173°C) and further cooked until unacceptable. DNA was extracted from samples taken after cooking and a 271bp fragment of the mitochondrial DNA was amplified by PCR. The results indicated that with the exception of pan frying for 80min, beef was determined in all meat samples including the broth and sauce of the roasted meat.     

禁食时间对宰后早期鸡肉持水力和嫩度的影响

三黄鸡分别禁食0、8、16h和24h,三管齐断法宰杀,于宰后5h内分别测定滴水损失、蒸煮损失、加压损失、蛋白溶解性、剪切力值、糖原、乳酸和pH值等指标,观察禁食对宰后早期鸡肉持水力和嫩度的影响。结果表明：随着禁食时间延长,宰后糖原含量(P＜0.05)和pH值均降低;随着宰后时间延长,糖原含量和pH值变化趋势与宰后时间正相关,而乳酸含量变化趋势与宰后时间负相关。宰后早期,pH值对肌肉持水力有显著影响(P＜0.05),而蛋白溶解度对持水力变化贡献不大。禁食使得宰后早期肌肉剪切力值有增大趋势,但处理组之间差异不显著。与未禁食鸡相比,禁食8h和禁食16h能够提高宰后肌肉持水力。     

冻融次数对牦牛肉胶原蛋白特性及品质的影响

为探究冻融次数对牦牛肉胶原蛋白特性和品质的影响。以牦牛肉为研究对象,分析不同冻融次数下牦牛肉剪切力、pH、解冻损失、蒸煮损失、色差、质构、胶原蛋白含量及溶解性、酶活性及微观结构的变化规律。结果表明,随着冻融次数的增加,牦牛肉剪切力下降了59.72%,牦牛肉胶原蛋白溶解性、β-半乳糖苷酶和β-半乳糖醛酶活力、解冻损失、蒸煮损失和b^*值显著上升(P<0.05),胶原蛋白含量、剪切力、pH、L^*值、a^*值以及质构显著下降(P<0.05)。相关性分析表明:剪切力与L^*值、a^*值、pH、胶原蛋白含量和溶解性、质构指标呈显著正相关(P<0.01),与解冻损失、蒸煮损失、b^*值、β-半乳糖苷酶活性和β-葡糖醛酸酶活性呈极显著负相关(P<0.001);pH与胶原蛋白特性呈极显著正相关(P<0.001);胶原蛋白特性与质构指标呈极显著正相关(P<0.001)。牦牛肉组织结构随冻融次数增加表现为破坏严重,肌纤维边界模糊。综上,冻融次数增加,...