Tenderness and oxidative stability of post-mortem muscles from mature cows of various ages

Two experiments were conducted to investigate the influence of age of mature cows (2-4yr, 6-8yr, and 10-12yr cows; n=6 in each) on beef quality. In Experiment 1, Longissimus dorsi (LD) steaks were stored at 3°C for 0-10d. Steaks from more mature cows had an increased (P<0.05) Warner-Bratzler shear force (WBSF) and a slower troponin-T post-mortem degradation. Storage reduced WBSF in all steak samples regardless of animal age. In Experiment 2, Semitendinosus (ST) and Semimembranosus (SM) patties were stored at 3°C for 0-7d simulating retail display. The rate of lipid oxidation during storage increased with animal age (P<0.05) and was greater in ST than in SM patties. However, myoglobin oxidation was minimally affected by animal age. Thus, advanced maturation not only intensified cow meat toughness but also lowered its oxidative stability.     

Profile of biochemical traits influencing tenderness of muscles from the beef round

The objective of this study was to define the biochemical differences that govern tenderness and palatability of economically important muscles from the beef round using cuts with known tenderness differences. At 24h postmortem, the longissimus dorsi (LD), gracillus (GR), adductor (AD), semimembranosus (SM), sartorius (SAR), vastus lateralis (VL), and vastus intermedius (VI) muscles were removed from ten market weight beef cattle. Sensory and biochemical characteristics were determined in each cut and compared with the LD. The GR, SAR and VI had sensory traits similar to the LD while the SM, AD and VL differed. The GR, SAR, AD, and SM all had multiple biochemical characteristics similar to the LD, while the VI and AD had numerous biochemical differences. While no one biochemical characteristic can be used to predict tenderness across all muscles, analysis of the biochemical characteristics revealed that in most beef round cuts postmortem proteolysis provided a good indication of the tenderization occurring during aging.     

Effects of blade tenderization on some quality characteristics of the muscles of mature ewes

 The effects of blade tenderization (BT) on some of the quality characteristics of longissimus dorsi (LD) and semimembranosus (SM) muscles from the carcasses of mature ewes were evaluated in this research. Values describing panel tenderness (P<0.01) and residue after chewing (P<0.05) were significantly improved by BT. Also, the number of chews before swallowing was significantly reduced (P<0.01) in the tenderized samples. The LD muscle had a significantly better (P>0.01) panel tenderness score and number of chews value than the SM muscle. BT influenced significantly (P<0.05) the initial yield force values of the Instron Warner-Bratzler test, which were 5.42±0.40 kg and 6.45±0.42 kg for tenderized and non-tenderized samples, respectively. Peak force and work done values were also significantly (P<0.01) affected by BT. The LD muscle had a lower peak force value (5.88±0.39 kg vs 7.06±0.43 kg) than the SM muscle. However, other Instron Warner-Bratzler test parameters were not significantly (P>0.05) affected by muscle type. The chewiness, hardness, peak force 2 and work done 2 values determined by the Instron compression test were significantly affected by muscle type. Also, BT resulted in lower values for chewiness, hardness, peak force 1 and 2, and work done 1 and 2 values, but the differences between tenderized and non-tenderized samples were not statistically significant (P>0.05). Received: 16 July 1998 / Revised version: 14 October 1998     

Effect of pre-slaughter physiological conditions on the oxidative stability of colour and lipid during chill storage of pork

The potential to tenderize beef muscles by the injection of lactic acid (0.5 M, 10% w/w) was studied using the pectoralis profundus muscle from cull cows. The injection was performed either 1 h (pre rigor) or 24 h (post rigor) post mortem, and the meat was stored for 2 or 14 days post mortem. Both treatments caused a rapid pH drop to around 5.0 within 4 h of injection. Other effects were: (1) an accelerated release of lysosomal enzymes into the cytosol; (2) a greater degradation of myosin heavy chains; (3) ultrastructural alterations of the myofibrils which included a general weakening or rupture in the M-lines and, to a lesser extent, in the I-bands; (4) a decreased heat stability of perimysial collagen indicated by a lower insoluble collagen content, lower differential scanning calorimetry transition temperature, and lower transition temperatures in isometric tension tests on muscle strips. The lactic acid injections improved significantly the textural traits of the meat (shear value, tensile strength, sensory scores) at 2 days post mortem with little further improvement when storage was extended to 14 days post mortem. Changes in texture were of similar amplitude at both post mortem injection times. The tenderization mechanisms of lactic acid injection are discussed.     

Influence of sodium chloride and pH during acidic marination on water retention and mechanical properties of turkey breast meat

Turkey breast cubes underwent acidic marination in the presence of salt. The transfer of water, salt and acid was measured, and texture was assessed on the cooked meat. While significant mass gains were observed during marination, from 20 minutes of immersion onwards, only long durations produced an overall matter balance greater than that of non-marinated meat. From the first minutes of immersion, these transfers caused hardening, regardless of the presence of salt in the marinade. For longer durations, only in the absence of salt was significant tenderizing seen in comparison to the non-marinated control. This effect appears to be due on the one hand to passing the isoelectric pH of the meat during acidification, and on the other hand to setting up antagonistic mechanisms breaking down or reinforcing connective tissues by acid and salt respectively. The high degree of tenderization observed in a water–acid solution can be explained partly by dilution of the fiber load per section unit due to protein solubilization.     

Effect of low voltage electrical stimulation on protein and quality changes in bovine muscles during postmortem aging

This experiment was conducted to determine the influence of low voltage electrical stimulation (ES) on the tenderness development of beef round muscles. Eight steers were slaughtered, and ES applied to one side of each carcass within 90 min of exsanguination. Steaks from M. longissimus dorsi, semimembranosus, adductor, and gracilis were vacuum packaged and aged at 4 °C for 9 d. Star probe, sensory evaluation, Western blot assays of troponin-T and μ-calpain autolysis and 2D-DIGE were conducted. ES resulted in accelerated (P < 0.05) pH decline of the longissimus in the first 24 h postmortem. ES did not influence (P > 0.05) proteolysis and tenderness, but did alter the predominance of metabolic proteins in the soluble fraction of muscle. Aging for 9 d improved tenderness (P < 0.05). The data confirmed that low voltage ES at 90 min of exsanguination had no effect on proteolysis and tenderness development in the longissimus dorsi, semimembranosus, adductor or gracilis in beef.     

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.     

Effect of salt addition on sous vide cooked whole beef muscles from Argentina

Sodium chloride (NaCl, 0-1.4%) and sodium tripolyphosphate (STPP, 0-0.5%) were added to Semitendinosus muscles and submitted to sous vide cooking at different temperatures (55-75°C). The effects of these three factors on pH, cooking loss, instrumental colour parameters, protein solubilization and distribution, and micro- and ultra-structure were evaluated. Quadratic surface responses equations were obtained from data (pH, cooking loss and colour parameters) as a function of the salts concentrations and cooking temperature. Both salts - alone or in combination - successfully reduced cooking loss. The best results were obtained for the combinations 0.25%STPP+1.20%NaCl and 0.25%STPP+0.70%NaCl, and temperatures between 60 and 65°C. Under these conditions, cooking loss was reduced close to 0%. pH was only dependent on STPP concentration, with a threshold concentration value of 0.25%. Temperature increment and NaCl addition produced a redness reduction. STPP incorporation recovered partially this parameter in comparison to non-added samples. Microscopy and SDS-PAGE results support the effect of the selected combinations of factors, suggesting that both salts together induced protein solubilization and gelation upon heating.     

Effects of pelvic suspension of beef carcasses on quality and physical traits of five muscles from four gender-age groups

Pelvic and Achilles suspension methods for beef carcasses were compared for four gender-age groups (24 month bulls, 34 month bulls, heifers, and cows) and five muscles [M. longissimus dorsi (LD), M. semimembranosus (SM), M. adductor (AD), M. psoas major (PM), and M. gluteus medius (GM)]. Pelvic suspension increased muscle and sarcomere lengths in the SM, LD, GM, and AD muscles. The following effects were significant (p < 0.05). Peak force was reduced by pelvic suspension in the LD and GM of bulls-24 and bulls-34, but not heifers and cows. Furthermore, peak forces decreased for the SM after pelvic suspension in bulls-24, bulls-34, and heifers. For the AD, the only decrease in peak force was for bulls-34. Water-holding capacity increased and purge in vacuum bags decreased for pelvic suspension of all muscles except the PM. Although the effects of pelvic suspension varied somewhat between gender-age groups and muscles, this method of hanging carcasses merits industrial consideration because it improves muscle yields, tenderness, and reduces variation within muscles.     

Effects of electrical stimulation, chilling temperature and hot-boning on the tenderness of bovine muscles

The objective of this study was to determine the effects of hot-boning, low voltage electrical stimulation (ES) and chilling temperature on the tenderness of bovine M. longissimus dorsi (LD) and M. semimembranosus (SM) muscles. LD (n=32) and SM (n=32) muscles were subjected to different post-mortem treatments; hot-boning (before 90min post-mortem), cold-boning (at 48h post-mortem), low voltage ES and rapid or slow chilling. Hot-boned muscles which were not electrically stimulated (NES) had higher Warner Bratzler shear force (WBSF) values (P<0.001) and shorter sarcomeres (P<0.001) than cold-boned muscles. Hot-boned muscles subjected to ES had lower pH values (P<0.001) post-stimulation and up to 8h post-mortem than NES muscles. At both chilling temperatures WBSF values were lower in ES hot-boned LD and SM muscles at days 2, 7 and 14 post-mortem than NES muscles. Hot-boned muscles subjected to slow chilling had longer sarcomeres (P<0.001) than those subjected to fast chilling. In hot-boned SM muscles, ES resulted in longer sarcomere lengths (P<0.001). However, ES did not have a significant effect on the sarcomere length of LD muscles. As indicated by WBSF values all muscles tenderised during ageing, including muscles which were 'cold shortened'. Proteolysis was not the main reason for differences in WBSF values between ES and NES muscles as judged by qualitative sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). A combination of slow chilling and ES had a positive effect on hot-boned muscles with respect to WBSF values.     

Working chute behavior of feedlot cattle can be an indication of cattle temperament and beef carcass composition and quality

The relationship between working chute temperament and beef carcass quality traits were measured on 183 crossbred feedlot steers. Steers were weighed and sorted into 16 pens and weighed every 28 days. Temperament was evaluated as exit velocity (EV), chute score (CS), and catch score (CAPS). Tissue samples were collected for DNA profile including docility (IGENITY^®, Merial Limited, Duluth, GA, USA). Steers were harvested at 14 to 16 months of age (606 ± 52 kg). Exit velocity increased and CS and CAPS values declined over time. Steers receiving a lower CAPS score had more marbling (P = 0.02). Ribeye steaks from steers with a slow first recorded EV were more tender (P = 0.02) than steaks from faster EV steers. IGENITY^® docility index had a positive (P = 0.09) correlation (r = 0.15) with Warner–Bratzler shear force (WBS) indicating a higher docility index was loosely associated with tougher meat.     

Factors influencing the variation in tenderness of seven major beef muscles from three Angus and Brahman breed crosses

Beef carcasses (n=30) from 3/4 Angus (A)×1/4 Brahman (B), 1/4A×3/4B, and 1/2A×1/2B F(1) crosses were used to evaluate breed type, electrical stimulation, and postmortem aging on the M. semimembranosus (SM), M. semitendinosus (ST), M. biceps femoris (BF), M. vastus lateralis (VL), M. gluteus medius (GM), M. longissimus dorsi lumborum (LD), and M. triceps brachii (TB). Shear force values decreased with increased postmortem aging to a greater extent in steaks from 3/4A×1/4B than steaks from the other breed types. Shear force values for steaks from the round (SM, ST, BF, VL) were higher than steaks from the loin (LD, GM) and chuck (TB) for both electrically stimulated and non-electrically stimulated muscles. In the LD muscle, calpastatin activities were similar among breed types. Muscle type played the greatest role in determining tenderness.     

Effect of age and cut on cooking loss, juiciness and flavour of South African beef

The juiciness and flavour characteristics of 15 aged primal beef cuts of electrically stimulated carcasses, from three different age groups, were assessed (n=61). Cooking losses were determined and proximate analyses (moisture, fat, nitrogen and ash) were performed. Tender cuts were cooked by a dry heat method, and less tender cuts were cooked by moist heat methods. A trained panel (n=10) evaluated sensory quality characteristics including initial and sustained juiciness, aroma and flavour. Flavour intensity was the biggest discriminant between the three age groups and declined with an increase in age. Initial impression of juiciness decreased with increased age of the animal and cooking losses increased nonlinearly with age, irrespective of the muscle. In contrast sustained juiciness increased with increased age. Cuts cooked according to a dry heat cooking method were reported juicier (both initial and sustained) than those cooked by moist heat methods.     

Effect of microwave cooking on the microstructure and quality of meat in goat and lamb

Fat cell distribution in the structure of semimembranosus muscle of goat and lamb was studied. The effect of various heating methods including conventional, domestic and industrial microwave were investigated using fluorescent light microscopy. Frequency used for microwave heating was 2450 MHz with two wattages levels of 700 (domestic microwave) and 12000 (industrial microwave). All samples were heated to internal temperature of 70 °C. The roasted samples in conventional oven were compared with microwave cooking. Fat distribution was different in various heat treatments. The roasted samples had greater fat retention in semimembranosus muscle. Results showed that uneven distribution of fat in muscle system influenced fat loss during cooking. The fat cells in the interior of muscle were lost more slowly compared to the fat located near the surface of the muscle. The overall migration of fat globules during microwave cooking was higher than conventional cooking.     

Effect of freezing on sensory quality, shear force and water loss in beef M. longissimus dorsi

The objective of this study was to determine how sensory quality, shear force and water loss differ between beef stored either chilled or frozen before cooking. Meat tenderness was analysed instrumentally and sensorially using both a consumer panel and a semi-trained panel. Both M. longissimus dorsi (LD) from eight young Holstein bulls were cut into eight samples, weighed, vacuum packed and aged at 4 °C for 2, 7 or 14 days. After ageing, the frozen samples were kept at −20 °C prior to heat treatment. Water holding capacity was recorded as purge or thawing loss and cooking loss or as combined loss. Sensory analyses were performed on samples aged 7 days. Peak force values declined with ageing time and freezing. Frozen meat aged 2 days had the same peak force values as chilled meat aged 7 days. Total energy was the same for both treatments at day 2 and 7, whereas at day 14 frozen samples showed significantly higher values than chilled samples. The sensory panel experienced the chilled meat to be more tender, juicier and having a more intense meat taste than the frozen meat, whereas the consumers could not find any significant difference in degree of liking. Water holding capacity was lower for the frozen samples. The results indicate that conclusions from studies concerning sensory quality of beef will depend on whether the meat has been kept chilled or frozen before testing.     

Effects of ohmic heating for pre-cooking of meatballs on some quality and safety attributes

Effectiveness of ohmic treatment on some quality attributes of semi-cooked meatballs was studied. Meatball samples were semi-cooked by 15.26 V/cm voltage gradient and 0 s holding time at 75 °C. Although ohmic cooking significantly reduced the numbers of total mesophilic aerobic bacteria, mould-yeast, Staphylococcus aureus and completely eliminated Salmonella spp. from meatball samples (p < 0.05), it was not found efficient to inactivate all Listeria monocytogenes cells. Ohmic semi-cooking process was resulted at higher cooking yields, which were supported by high fat and moisture retention values in meatball samples. Metal levels (iron, chromium, nickel and manganese) of ohmically semi-cooked meatball samples were found below the upper level of dietary exposure levels. Ohmic cooking procedure was found to be safe in terms of PAH formation and mutagenic activity. Sensory evaluation showed that the overall acceptance of the semi-cooked meatball samples were good. These results demonstrate considerable potential for the application of ohmic process for semi-cooking of meatballs.     

Effects of breed and marination on the sensory attributes of pork from Large White and Hampshire-sired pigs

The effects of breed and marination were tested for their effects on meat pH, water holding (marinade uptake and losses) and eating quality (tenderness, juiciness and flavour).

Loins were removed from one side of 20 Large White-sired and 20 Hampshire-sired pigs after slaughter, cut into four pieces and injected to 112% of their initial weight with water, a polyphosphate-containing marinade (pH 7.7) or a high pH marinade (pH 10.3). An uninjected piece of loin served as control. Samples were left overnight and then frozen before being thawed, cooked and assessed by a trained ten member sensory panel using 1–8 category scales.

Hampshires had higher intramuscular fat (0.95%) than Large Whites (0.62%) but otherwise the effects of breed were small compared with marination. Both marinades significantly increased meat pH from 5.5 (control) by 0.2 U, significantly reduced the cooking loss and increased the meat yield from about 80% to 90%. Water-injected samples lost large amounts of added water as drip after thawing and had a yield (76%) similar to the control. Marinaded samples retained more water post-cooking. Both marinades significantly increased tenderness (p < 0.001) and juiciness (p < 0.001) by about 1.0 U compared with the control (4.4 for tenderness and 4.2 for juiciness). Pork flavour, however, was significantly reduced (p < 0.001) and abnormal flavour was significantly increased (p < 0.001) by marination. Tenderness was positively correlated with pH after injection (0.83) and yield (0.75); juiciness was also positively correlated with pH after injection (0.78) and yield (0.87).

The absence of any significant difference in eating quality between control and water-injected samples, and the relatively large effects of marination, suggest that retained water (after cooking) is crucial in determining perceived tenderness and juiciness in pork.     

The comparison of three β-agonists for growth performance,carcass characteristics and meat quality of feedlot cattle

Forty-eight Bonsmara steers were assigned to three treatment groups and one control group consisting of 12 animals each. The control (C) received no β-agonist, while the three treatment groups received zilpaterol (6 ppm) (Z), ractopamine (30 ppm) (R) or clenbuterol (2 ppm) (Cl) for the last thirty days on feed. Growth performance (final 30 days), USDA quality and yield grades and meat quality (shear force, chemical, histological and biochemical) were compared for the three β-agonist and control groups. Animals responded negatively to Cl treatment during initial stages of supplementation, which was evident in lower feed consumption and initial growth rates. For carcass growth and yield, Cl had greater and more efficient growth rates, higher dressed out yields (proportional), lower USDA yield grades, and reduced marbling compared with C (P < 0.05). For meat quality measurements, the M. longissimus (LL) and M. semitendinosus (ST) were sampled. Cl had the greatest effect (P < 0.05) on WBSF, especially on the LL, followed by Z. Variation in tenderness and ageing effects corresponded with variation in calpastatin activity and myofibrillar fragmentation between treatment groups. While zilpaterol and ractopamine are currently the only products registered for cattle in different countries, it seems that zilpaterol has an advantage in carcass growth efficiency and yield without showing any adaptation problems for animals such as experienced by the more aggressive β-agonist clenbuterol.     

Effect of high power ultrasound and ageing on the physical properties of bovine Semitendinosus and Longissimus muscles

Tenderness is an important meat quality parameters and the use of high power ultrasound to disrupt muscle structure may prove effective for reducing both myofibrillar and collagenous toughness. The experiment was carried out with Longissimus lumborum et thoracis and Semitendinosus muscles from 3 to 4 year old steers. Uncooked beef samples (60 × 40 × 20 mm) were treated with high power ultrasound (24 kHz, 12 W/cm²) for up to 240 s, and aged for up to 8.5 days before evaluation of pH, drip loss, cook losses Warner–Bratzler shear (WBS), compression hardness, and colour. Ultrasound treatment significantly reduced WBS force and hardness, but significantly increased pH. Ageing significantly reduced hardness and WBS force, but there was no significant interaction between ultrasound treatment and ageing time. Ultrasound treatment did not affect any of the colour parameters (L^*a^*b^*, chroma and hue) but the ageing time significantly increased the lightness, chroma and hue. There was no significant effect of ultrasound treatment on drip loss, but it did significantly reduce the cook and total loss. During ageing, cook loss and total losses significantly increased. The results suggest that high power ultrasound is capable of reducing objective texture measurements of beef without compromising the other quality parameters investigated.     

Effect of microwave treatment on the cooking and macronutrient qualities of pulses

The effect of microwave treatment to reduce the cooking times of five pulses, namely red lentil, chickpea, pigeon pea, mung bean, and pinto bean, were determined in this study. Pulses from 10 to 18% moisture contents were treated using 400 to 600 W microwaves for 14 to 56 s. The cooking times of microwave-treated pulses were significantly lower than that of the control samples. The lowest cooking time was observed for 18% moisture content chickpea and pigeon pea treated with 600 W for 56 s. The Fourier transform mid-infrared spectra in both lipids and fingerprint regions showed the macronutrients differences among the five pulses. Major changes were observed in the amide I region of microwave treated pulses. This effect of microwave treatment was higher in red lentil, chickpea, and mung bean than in pigeon pea and pinto bean at 10% moisture content. At 18% moisture content, the change of β-sheets to aggregates was observed in all pulses due to microwave treatment.