Comparison of methods for measuring shear force and sarcomere length and their relationship with sensorial tenderness of longissimus muscle in beef

Slice shear force (SSF) and laser diffraction, considered faster methodologies, for measuring beef instrumental tenderness and sarcomere length, were compared with reference methodologies Warner–Bratzler shear force (WBSF) and phase contrast microscopy. Striploin samples (n = 74) were analyzed for pH, sarcomere length, instrumental tenderness, myofibrillar fragmentation index, and sensorial tenderness. Pearson's correlation measured the association of meat evaluation methods with residual analysis of the multivariate analysis of variance model. The n-dimensional profile to evaluated methods was presented by biplot to identify the behavior of the correlation between the methods (variables). There was moderate correlation between SSF and WBSF (r = .63; p < .01) and both presented moderate correlation with sensorial tenderness (r = − .62 and −.55, to SSF and WBSF, respectively; p < .01). However, WBSF was more efficient to classify samples as tender (68%) than SSF (47%), comparing with sensorial tenderness (80%). There was a moderate correlation for laser and microscopy for sarcomere length (r = .57; p < .01). Sarcomeres were shorter when measured by laser than microscopy. Either with low correlation coefficients, sarcomere measured by laser (r = .29; p < .05) presented higher correlation with sensorial tenderness than with microscopy (r = .22; p < .10). Results highlighted that SSF was faster and easier to run, while WBSF was more appropriate to classify samples by sensorial tenderness grades. Laser diffraction is more suitable to explain effects on tenderness; however, microscopy revealed results of sarcomere length that were more realistic, once laser can underestimate sarcomeres.     

CONSUMER EVALUATION OF THE PALATABILITY OF USDA SELECT,USDA CHOICE AND CERTIFIED ANGUS BEEF STRIP LOIN STEAKS FROM RETAIL MARKETS IN LUBBOCK,TEXAS, U.S.A.

ABSTRACT

Select, Choice and Certified Angus Beef (CAB) strip loin steaks were sold in Lubbock, TX to determine consumer acceptability. A home survey was attached to each package of steaks (return = 191 steak evaluations). Consumers did not detect differences in tenderness or flavor, but rated CAB steaks juicier (P < 0.05) than Select or Choice. However, 68% of CAB consumers rated steaks as extremely or very tender, but less than half rated Choice and Select steaks the same way. Consumer tenderness and flavor scores for Select steaks were more variable, but consumer satisfaction and tenderness acceptability did not differ (P > 0.05) between grades. Trained sensory panelists rated CAB steaks higher (P < 0.05) than Choice or Select for all palatability traits except flavor intensity. Shear force decreased (P < 0.05) by quality grade as CAB steaks sheared with the least resistance. These results showed marbling influenced objective palatability measures and decreased the variation in both objective and consumer measures of palatability.

PRACTICAL APPLICATIONS

Quality grades were established to predict beef palatability, but marbling can be an unreliable predictor of tenderness. Branded beef programs, such as Certified Angus Beef (CAB), have been developed to distinguish higher palatability products and provide more consistent products for consumers. Consumers can distinguish between levels beef tenderness and are willing to pay a premium for tender beef. Moreover, consumers find product consistency is moderately important when purchasing fresh beef. Therefore, the purpose of this study was to determine consumer acceptability based on in‐home evaluations of strip loin steaks from United States Department of Agriculture Select and Choice grades and CAB purchased from a retail supermarket environment.

     

Evaluation of Longissimus dorsi muscle pH at three hours Post mortem as a predictor of beef tenderness

The objective of this study was to determine the relationship of beef longissimus dorsi muscle (LM) pH at 3 h post mortem (pH(3)) and aged LM tenderness. The cattle (n = 444) sampled for this experiment represented various breed types, sex classes, feeding regimes, and post-mortem handling practices. The phenotypic diversity of the cattle used provided a great amount of variation in Warner-Bratzler shear (WBS) force (Coefficient of variation for pH, temperature, and sarcomere length measurements were much smaller than the coefficient of variation for WBS force). None of the parameters measured (LM pH at 3 and 48 h post mortem, temperature at 3 h post mortem and sarcomere length) was strongly related to tenderness. These results do not support the use of pH(3) as a criterion for sorting beef carcasses into expected tenderness groups.     

Effect of pre rigor stretching on beef tenderness development

The objective of this study was to determine effects of pre rigor stretching on beef tenderness development. Beef loins (M. longissimus dorsi; n=24) were assigned to either stretching or non-stretching treatments and aged for 14days at -1.5°C. Sarcomere length, shear force, water-holding capacity and proteolysis were determined for the loins at 1, 7 and 14days of ageing. Stretching increased the length of the loins by 33% resulting in a trend of increasing sarcomere length (P=0.19). However, no significant differences for shear force values, purge, drip and cooking losses between treatments were found. Shear force values decreased with ageing times (P<0.05). Western blot assay found that stretching did not affect the extent of desmin degradation. The findings from the present study suggest that pre rigor stretching with the current increase in length will not contribute to tenderness improvement of the beef loins.     

The influence of biochemical differences on the variation in tenderness of M. longissimus dorsi of Belgian Blue steers managed homogenously pre and post-slaughter

The objective of this experiment was to determine the contribution of some biochemical processes of postmortem muscle to the variation in tenderness of beef from Belgian Blue bull cross Holstein-Friesian steers (n=10). These animals were managed optimally from conception to consumption with the aim of reducing tenderness variation. The M. longissimus dorsi (LD) from the left hand side (LHS) and the right hand side (RHS) were analysed for variation in tenderness using Bartletts test. The quality measurements included pH, temperature, Warner Bratzler shear force, sensory tenderness, chemical composition and sarcomere length. Biochemical measurements included myofibrilar proteolysis, glycolytic potential, adenine/inosine ratio and collagen content. No difference for variances or means were observed between LHS and RHS for chemical, quality or biochemical attributes. Biochemical variation was greater than the variation observed in most of the quality attributes measured. Proteolysis was the main biochemical contributor to the variation in shear force tenderness after 2 and 7 as postmortem, but not sensory tenderness. Glycolysis levels and adenine/inosine ratio explained much of the variation in sensory tenderness, but not WBSF. Collagen content in the LD muscles did not explain variation in shear force or sensory tenderness. This would suggest biochemical variation is one of the main contributors to variation in tenderness of beef managed optimally pre- and post-slaughter.     

Alternative pre-rigor foreshank positioning can improve beef shoulder muscle tenderness

Thirty beef carcasses were harvested and the foreshank of each side was independently positioned (cranial, natural, parallel, or caudal) 1 h post-mortem to determine the effect of foreshank angle at rigor mortis on the sarcomere length and tenderness of six beef shoulder muscles. The infraspinatus (IS), pectoralis profundus (PP), serratus ventralis (SV), supraspinatus (SS), teres major (TM) and triceps brachii (TB) were excised 48 h post-mortem for Warner–Bratzler shear force (WBSF) and sarcomere length evaluations. All muscles except the SS had altered (P < 0.05) sarcomere lengths between positions; the cranial position resulted in the longest sarcomeres for the SV and TB muscles whilst the natural position had longer sarcomeres for the PP and TM muscles. The SV from the cranial position had lower (P < 0.05) shear than the caudal position and TB from the natural position had lower (P < 0.05) shear than the parallel or caudal positions. Sarcomere length was moderately correlated (r = − 0.63; P < 0.01) to shear force.     

Hot processing and grind size affect properties of cooked beef patties

This study was conducted to further understand the role that hot processing and grind size exert on cooked beef patty tenderness and other properties. Low-fat (10%) hot-processed (HP) and cold-processed (CP) beef were ground either through a 0.32 or 0.40 cm plate. A 20% fat CP product was also manufactured through a 0.32 cm plate. HP patties had higher pH, shorter sarcomere lengths, higher tenderness scores (including greater number of smaller particles during chewing) lower shear force values, higher flavor scores, less well-done cooked color, longer cooking times and higher cooking yields than CP patties (p<0.01). The use of a 0.32 cm rather than a 0.40 cm plate improved tenderness properties, especially for HP patties. Other properties were not greatly influenced by grind size. Sensory evaluation and scanning imagery of patties suggested that the greater tenderness of hot processed patties may be due to the presence of smaller meat particles. Highly contracted muscle, providing resistance to grinding, could be responsible for the small meat particles.     

不同杂交品种肉牛背最长肌纤维组织学结构与嫩度对比研究

选择16个月龄的西门塔尔牛、夏洛莱牛、红安格斯牛品种高代杂种牛以及草原红牛,在相同饲养管理条件下育肥180d后屠宰。研究品种对肉牛背最长肌纤维组织学结构及嫩度的影响。结果表明：草原红牛肌纤维直径最大为（48．16±2．98）μm,肌节长度最短为（1．84±0．09）μm,剪切力值最大为（7．31±0．46）N,背最长肌肌肉嫩度较其他品种差;红安格斯牛肌纤维直径最小为（37．77±3．21）μm,肌纤维肌节长度最长为（2．08±0．09）μm,剪切力值最小（5．70±0．74）N,背最长肌肌肉嫩度较其他品种好。     

Inhibition of the proliferation of myeloma cells by the meat origin strain Enterococcus faecium CH3

Sides of 31 non-stimulated carcasses of young bulls were subjected to the muscle stretching methods Tenderstretch (TS) by pelvic bone suspension or Tendercut (TC) with two skeletal cuts or served as controls by traditional Achilles tendon suspension. The sides were chilled at fast and medium rates, resulting in temperatures of 4-5 and 9°C in the m. longissimus dorsi (LD) at 10 h post mortem. The LDs were examined for sarcomere length, Warner-Bratzler peak shear force and sensory properties after 8 days of ageing at 4°C. At the fast chilling rate, TS and TC increased sarcomere lengths, reduced shear force and improved sensory tenderness of the LDs compared to the controls (P<0.05). At the medium chilling rate, sarcomere lengths increased (P<0.05), but no significant differences were found in shear force or sensory tenderness (P>0.05) of the muscles due to stretching. However, the medium chilling rate was efficient in producing tender LDs without applying muscle stretching methods. TS and TC are feasible alternatives for improving overall tenderness and reducing variation in tenderness of beef LD at cold shortening chilling conditions.     

Factors associated with tenderness in young beef

One hundred and twenty-two crossbred steers of varying percentages of Bos Indicus and Bos Taurus breeding were slaughtered to determine the relationship of carcass and meat characteristics to tenderness. Carcasses were graded and longissimus dorsi muscle samples were evaluated for fibre type characteristics, sensory and shear force determination, sarcomere length, intramuscular fat content, collagen content and solubility and fragmentation index. Sarcomere length and collagen content and solubility were not significantly related to shear force values or sensory tenderness ratings. The fragmentation index was highly correlated to sensory tenderness ratings (r = −0·60) and shear force values (r = 0·53) indicating that variation in tenderness is associated with myofibrillar protein degradation. A four variable regression equation that included fragmentation index, lean colour, marbling and per cent red fibres accounted for 56% of the variation in sensory tenderness. Fragmentation index directly accounted for 30% of the variation in sensory tenderness in the four variable equation.     

Effect of pre rigor stretching on beef tenderness development

The objective of this study was to determine effects of pre rigor stretching on beef tenderness development. Beef loins (M. longissimus dorsi; n = 24) were assigned to either stretching or non-stretching treatments and aged for 14 days at − 1.5 °C. Sarcomere length, shear force, water-holding capacity and proteolysis were determined for the loins at 1, 7 and 14 days of ageing. Stretching increased the length of the loins by 33% resulting in a trend of increasing sarcomere length (P = 0.19). However, no significant differences for shear force values, purge, drip and cooking losses between treatments were found. Shear force values decreased with ageing times (P < 0.05). Western blot assay found that stretching did not affect the extent of desmin degradation. The findings from the present study suggest that pre rigor stretching with the current increase in length will not contribute to tenderness improvement of the beef loins.     

Partial least squares analysis of near-infrared hyperspectral images for beef tenderness prediction

Tenderness is a primary determinant of consumer satisfaction of beef steaks. The objective of this study was to implement and test near-infrared (NIR) hyperspectral imaging to forecast 14-day aged, cooked beef tenderness from the hyperspectral images of fresh ribeye steaks (n = 319) acquired at 3–5 day post-mortem. A pushbroom hyperspectral imaging system (wavelength range: 900–1700 nm) with a diffuse-flood lighting system was developed. After imaging, steaks were vacuum-packaged and aged until 14 days postmortem. After aging, the samples were cooked and slice shear force (SSF) values were collected as a tenderness reference. After reflectance calibration, a Region-of-Interest (ROI) of 150 × 300 pixels at the center of longissimus muscle was selected. Partial least squares regression (PLSR) was carried out on each ROI image to reduce the dimension along the spectral axis. Gray-level textural co-occurrence matrix analysis with two quantization levels (64 and 256) was conducted on the PLSR bands to extract second-order statistical textural features. These features were then used in a canonical discriminant model to predict three beef tenderness categories, namely tender (SSF ≤ 205.80 N), intermediate (205.80 N < SSF < 254.80 N), and tough (SSF ≥ 254.80 N). The model with a quantization level of 256 performed better than the one with a quantization level of 64. This model correctly classified 242 out of 314 samples with an overall accuracy of 77.0%. Fat, protein, and water absorption bands were identified between 900 and 1700 nm. Our results show that NIR hyperspectral imaging holds promise as an instrument for forecasting beef tenderness.     

Effects of hot boning and moisture enhancement on the eating quality of cull cow beef

The effects of chilling method and moisture enhancement were examined for improving eating quality of semimembranosus (SM) and longissimus lumborum (LL) from 62 cull beef cows. Chilling method included hot boning muscles after 45 to 60 min postmortem or conventional chilling for 24 h. Moisture enhancement included 1) a non-injected control (CONT) or injection processing (10% of product weight) using 2) Sodium Tripolyphosphate/salt (Na/STP), 3) Sodium Citrate (NaCIT), 4) Calcium Ascorbate (CaASC), or 5) Citrus Juices (CITRUS). Chilling method by moisture enhancement treatment interactions (P < 0.09) were due to decreased hue, chroma and sarcomere length values in hot boned vs. conventionally chilled product (SM and LL) for CaASC vs. other moisture enhancement treatments. Chilling method by moisture enhancement treatment interactions (P < 0.05) were due to decreased shear force and increased tenderness in conventionally chilled vs. hot boned LL using CaASC vs. Na/STP. Moisture enhancement can improve tenderness of cull cow beef depending on combinations of chilling method and moisture enhancement treatments used.     

BOVINE MUSCLE TENDERNESS AS RELATED TO PROTEIN SOLUBILITY

ABSTRACT— The longissimus (modest degree of marbling) from forty beef ribs selected 48–56 hr post-mortem was used in two trials. Trial I involved A, C and E maturity ribs (10 each classification). Each rib was subjectively scored for texture (fresh) and adjacent longissimus samples were removed for the determination of protein solubility (fresh) and tenderness. Tenderness (cooked muscle) was measured with a Warner-Bratzler shear and taste panel. Protein solubilities were determined using 0.154M Krebs-Ringer-Bicarbonate buffer, 0.2M KCl + 0.01M K phosphate buffer, 1.1M Kl + 0.1M K phosphate buffer, and 0.03M K phosphate buffer. Trial II involved 10 A maturity ribs. The 0.2M KCl, 1.1M Kl and 0.03M K phosphate buffers as described for trial I were used for protein extraction. Additionally, sarcomere length was measured in formalin. Multiple regression equations were developed to predict tenderness in trial II. Protein solubilities were not significantly different between the carcass maturity groups although there were trends toward increased solubility as maturity increased. Tenderness tended to decrease from A to E maturity indicating a negative relationship between protein solubility and tenderness. Several significant negative correlations between protein solubility and tenderness were found in trial I (A maturity group) and trial II. Additionally, several significant negative correlations between texture and solubility were calculated. Correlations within the C and E maturity groups were variable and showed no definite trends. Multiple regression analyses showed that a combination of protein solubilities, texture score and sarcomere length accounted for 88% of the variation in shear force and 72% of the variation in taste panel tenderness.     

Association of polymorphisms in the calpain I, calpain II and growth hormone genes with tenderness in bovine M. longissimus dorsi

The objective of this study was to determine if there is an association between tenderness in bovine M. longisimus dorsi (LD) and polymorphisms in the bovine calpain I (exons 9 & 14), calpain II (regulatory subunit) or growth hormone (intron 3) genes. Genomic DNA was isolated from bovine LD (n = 281) on which quality attributes (Warner Bratzler shear force (WBSF), sarcomere length and composition) were also characterised. DNA polymorphisms were analysed using polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis. Association analyses were performed between genotypes at the four polymorphic loci and day 14 WBSF values. It was found that the calpain 1 exon 9 genotypes had an association with WBSF such that animals with the GA genotype exhibited decreased WBSF and increased tenderness when compared to animals with the GG genotype (P < 0.05). This observation concurs with that of earlier studies, suggesting that this polymorphism is a functional marker for beef tenderness.     

延迟冷却对牛肉品质及超微结构影响的研究

本文研究了常规冷却与延迟冷却对中国杂交黄牛(鲁西黄牛×西门塔尔)宰后冷却过程中牛胴体pH值、温度变化、胴体冷却失重、肉色及成熟过程中剪切力值、背最长肌汁液损失、蒸煮损失、保水性、肌原纤维结构变化的影响.结果表明延迟冷却能减缓牛胴体温度的下降速率(P＜0.05),加快牛胴体pH值的降低(P＜0.05),提高牛背最长肌的嫩化速率,改善肉色(P＜0.05),但加剧了汁液损失、蒸煮损失,降低了保水性(P＜0.05).延迟冷却对成熟0d、3d时的肌原纤维结构影响显著(P＜0.05),延迟冷却组的肌节长度明显长于对照组的肌节长度.     

酱油种类及添加量对牛肱二头肌的嫩化作用

研究酱油种类及添加量对牛肱二头肌的嫩化作用。将3 种质量浓度15 g/100 mL的酱油溶液与3 g /100 mL的食盐溶液按不同的比例混合,配制9 组腌制液,并以3 g/100 mL的食盐溶液作为对照组（记为C0）,按肉液比为1∶4（m/V）将牛肱二头肌肉块（2.5 cm×2.5 cm×2.5 cm）腌制72 h（4 ℃）,分析酱油种类及添加量对肉样pH值、剪切力、胶原蛋白含量、肌节长度及肌原纤维碎裂指数（myofibrillar fragmentation index,MFI）等指标的影响。结果表明：酱油腌制会降低肉样的pH值（P＜0.05）,但对肉样的持水力和总胶原蛋白含量无显著影响（P＞0.05）;酱油含量高的腌制液具有更低的pH值,使肉样的可溶性胶原蛋白含量及MFI变大、肌节长度变短,进而提高肉的嫩度;当腌制液中的酱油比例较高时,肉样的嫩度与多汁性感官评分更高,总体可接受度更好。在3 种酱油中,低pH值酱油对牛肱二头肌的嫩化效果更好。     

An assessment of the role of pH differences in determining the relative tenderness of meat from bulls and steers

Samples of M. longissimus dorsi from 16-20 month Friesian bulls or steers (80/group) were assessed for a range of meat quality characteristics after being held at ambient temperature for 24h (to avoid cold-shortening) and then at 0-2°C for 6 days. Mean ultimate pH was significantly higher for samples from the bulls (6·35 versus 5·89), and as a consequence, reflectance values were lower, sarcomere lengths were shorter, and expressed juice and cooking losses were lower. Mean Warner-Bratzler shear values did not differ between the groups, apparently because the bull values were mainly above the peak of the pH/shear force curve, while the steer values were mainly below it. There was no evidence that the relationship between shear force and pH differed for samples from the bulls and steers. Results suggested that the increased shear force with increased pH up to 6·2 was at least partly due to a decreased sarcomere length. It is suggested that some of the differences in tenderness between beef from bulls and steers, that have been reported elsewhere, may have been largely due to differences in ultimate pH values.     

Explaining the variation in the shear force of lamb meat using sarcomere length, the rate of rigor onset and pH

The temperature when the pH=6.0 (temp@pH6) impacts on the tenderness and eating quality of sheep meat. Due to the expense, sarcomere length is not routinely measured as a variable to explain variation in shear force, but whether measures such as temp@pH6 are as useful a parameter needs to be established. Measures of rigor onset in 261 carcases, including the temp@pH6, were evaluated in this study for their ability to explain some of the variation in shear force. The results show that for 1 day aged product combinations of the temp@pH6, the pH at 18 °C and the pH at 24 h provided a larger reduction (almost double) in total shear force variation than sarcomere length alone, with pH at 24 h being the single best measure. For 5 day aged product, pH at 18 °C was the single best measure. Inclusion of sarcomere length did represent some improvement, but the marginal increase would not be cost effective.     

EFFECT, DEVELOPMENT AND OPTIMIZATION OF MIXING TEMPERATURE, TIME AND PARTICLE REDUCTION IN THE MANUFACTURE OF RESTRUCTURED BEEF STEAK

Restructured beef steaks were processed from USDA Select chuck muscles without the use of additives, and three processing variables were utilized at three different levels: -2, 0, +2C for mixing temperature, 12, 18, 24 min for mixing time and 1, 2, 3 passes through a kidney plate for particle size reduction. A sensory panel composed of 149 untrained consumer panelists evaluated the 27 treatment combinations for five sensory attributes. Instrumental determinations were also made. Increasing mixing temperature and decreasing particle size significantly decreased sensory tenderness, flavor and overall acceptance and increased instrumental hardness and springiness of the restructured beef steaks. Increasing mixing time had a significant effect on sensory appearance and on instrumental cohesiveness and gumminess. The means for sensory scores were used for a response surface analysis (RSM) to optimize the three processing variables. Significant models were found for tenderness (P<0.05), overall acceptance (P<0.05) and flavor (P<0.15). Using a sensory score of 6.00 (like slightly) as an acceptable score, optima for the processing variables were determined. To obtain an acceptable product, the meat should be ground by two passes through the kidney plate then mixed at a maximum temperature of 0.67C for 12 min.