Physical, Chemical and Sensory Characteristics of Four Types of Beef Steaks

Four types of beef forequarter steaks, rib eye roll steaks (RER), ser-ratus ventralis solid-muscle structured steaks (SRV), salt/phosphate comminuted structured steaks (NaCl/PO⁴) and algin/calcium comminuted structured steaks (Alg/Ca) were evaluated. Meat purchasers preferred the color, lack of surface discoloration and overall appearance of intact muscle steaks (RER and SRV) over the comminuted structured steaks (NaCl/PO⁴ and Alg/Ca). Purchasers perceived the fat content in SRV steaks to be less than in RER steaks. Sensory evaluations of juiciness and overall desirability were similar for all four types. Intact muscle steaks were lower in sensory tenderness ratings and higher in flavor desirability than comminuted structured steaks. Consumer acceptability was evident for all four types offering merchandising options to beef fabricators.     

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.

     

Postmortem Degradation of Titin and Nebulin of Beef Steaks Varying in Tenderness

Purified myofibrils were isolated from “tender” and “less-tender” bovine longissimus muscle at death and at 1, 3, 7, and 14 days of postmortem storage (4^oC). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect changes in the myofibrillar/cytoskeletal proteins, titin and nebulin. Titin and nebulin bands were observed to be less intense on gels from “tender” than from “less-tender” steaks. These results suggest that titin and nebulin were more rapidly degraded in “tender” than in “less-tender” steaks, and that the extent of beef loin steak tenderness may be dependent upon the postmortem degradation of titin and nebulin.     

Establishing tenderness thresholds of Venezuelan beef steaks using consumer and trained sensory panels

The tenderness thresholds for ribeye steaks at 2 d postmortem were found by using sensory trained (n = 734 steaks) and consumers panel data (55 ribeye steaks and 296 consumers). Also, consumers’ perceptions of sensory attributes of beef steaks were assessed to establish their relationships and to determine acceptability levels. The tenderness threshold obtained by regression analysis from trained panelists was 37.98 N (3.87 kg). Customer satisfaction of 81% was obtained when beef steaks had Warner-Bratzler shear force values (WBSF) less than 40.13 N (4.09 kg), suggesting that 40.13 N could be considered as a tenderness threshold to segregate tough from tender steaks, for Venezuelan beef consumers. According to correlation and regression analyses, consumers focused on flavor to assign their overall liking score. Results suggest that consumers are able to detect changes in tenderness of steaks with different WBSF and that flavor drives customer satisfaction when the beef tenderness is acceptable.     

Consumer Assessment of Beef Tenderloin Steaks from Various USDA Quality Grades at 3 Degrees of Doneness

A consumer study was conducted to determine palatability ratings of beef tenderloin steaks from USDA Choice, USDA Select, and USDA Select with marbling scores from Slight 50 to 100 (USDA High Select) cooked to various degrees of doneness. Steaks were randomly assigned to 1 of 3 degree of doneness categories: very‐rare, medium‐rare, or well‐done. Consumers (N = 315) were screened for preference of degree of doneness and fed 4 samples of their preferred doneness (a warm‐up and one from each USDA quality grade treatment in a random order). Consumers evaluated steaks on an 8‐point verbally anchored hedonic scale for tenderness, juiciness, flavor, and overall like as well as rated steaks as acceptable or unacceptable for all palatability traits. Quality grade had no effect (P > 0.05) on consumer ratings for tenderness, juiciness, flavor, and overall like scores, with all traits averaging above a 7 (“like very much”) on the 8‐point scale. In addition, no differences (P > 0.05) were found in the percentage of samples rated as acceptable for all palatability traits, with more than 94% of samples rated acceptable for each trait in all quality grades evaluated. Steaks cooked to well‐done had lower (P < 0.05) juiciness scores than steaks cooked to very‐rare or medium‐rare and were rated lower for tenderness (P < 0.05) than steaks cooked to a very‐rare degree of doneness. Results indicate consumers were not able to detect differences in tenderness, juiciness, flavor, or overall like among beef tenderloin steaks from USDA Choice and Select quality grades.     

INFLUENCE OF ANTIMICROBIAL COMPOUND(S) EXTRACTED FROM MILK FERMENTED BY STREPTOCOCCUS THERMOPHILUS ON KEEPING QUALITY OF MEAT AND MILK

The potential of a methanol-acetone (M-A) extract prepared from milk fermented by Streptococcus thermophilus in extending the shelf-life of meat and milk was investigated. In experiment I, increasing amounts (0, 0.1, 0.2 and 0.3 ml) of M-A extract with or without ascorbic acid were added to 20 g aliquots of ground beef subsequently stored at 5–7° C for 0, 3 and 6 days. Total and gramnegative bacterial counts and pH in ground beef treated with M-A extract were significantly (P<0.01) less than the corresponding values in control beef on days 3 and 6 for all dose levels tested with significant (P<0.01). In experiment II, rib-eye steaks were sprayed with H₂O or 0.1, 0.2 and 0.3 ml of M-A extract and stored at 5–7° C for 0, 3 and 6 days. The total and gram-negative bacterial counts on the surface of steaks sprayed with M-A extract were significantly (P<0.01) lower than the counts in control steaks. Also, in experiment III, inhibition of bacterial growth by M-A extract was significant (P<0.01 or 0.05) both in milk stored at either room temperature or 5–7° C. M-A extract inhibited the growth of Pseudomonas fluorescens inoculated into milk.     

Reducing Postmortem Aging Time of Beef with Electrical Stimulation

Two studies (Study 1 = 23 forage-fed steers; Study 2 = 20 grain-fed steers and heifers) were conducted to determine relationships of electrical stimulation (ES) and/or postmortem aging (PA) to tenderness of beef. For Study 1, steaks from ES sides had lower (P < 0.05) Warner-Bratzler shear (WBS) values than steaks from not-ES sides for each PA period. In addition, the percentage reduction in WBS values was greater for the steaks from the ES-Day 2 group (–29.5%) than for steaks from even the longest PA period (14 days) from the not-ES group (–25.8%). For Study 2, during the fist three PA periods (1, 2 and 5 days), ES resulted in more desirable (P < 0.05) flavor ratings (Day l), higher (P < 0.05) tenderness ratings and lower (P < 0.05) WBS values (Day 1, 2, 5) and more desirable (P < 0.05) overall palatability ratings (Day 1, 2). During the last three PA periods (8, 11 and 14 days), ES resulted in higher (P < 0.05) tenderness ratings (Day 8), lower (P < 0.05) juiciness ratings (Day 11, 14) and lower (P < 0.05) WBS values (Day 8). Based on these results, ES had the greatest impact on beef palatability if the period of aging was 8 days or less; with additional aging time, ES effects on palatability were negated. When each treatment (ES, not-ES) was divided into two groups based on median tenderness ratings for the not-ES group, ES had the greatest impact on those carcasses in the “tough” group while ES had little impact on those carcasses in the “tender” group. ES will accelerate the postmortem aging of beef but the aging time reduction and extent of ultimate tenderization appears to be affected by the inherent tenderness of the beef.     

USDA MATURITY INDICES AND PALATABILITY OF BEEF RIB STEAKS1

In a population of 195 beef carcasses, as maturity increased (by whole USDA groups) from A to B, flavor, tenderness and overall palatability ratings for rib steaks decreased (P < .05); further increases in maturity (B vs. E) resulted in subsequent decreases (P < .05) in tenderness and overall palatability. Subdivision of whole maturity groups into thirds and subsequent data analyses supported precepts in USDA grade standards of declining palatability with advancing maturity, but the declines, when they occurred, were nearly linear through the extremes (from A^? to E⁺) and did not support the concept, in USDA grade standards, of a precipitous decline in eating satisfaction at or near the B⁺/C^? maturity line. Among seven carcass maturity indices, all were similarly and singularly related (P < .05) to palatability of rib steaks, with some measure of skeletal maturity (the best of these was color/shape of the rib bones) plus some measure of muscle maturity (the best of these was color of the longissimus muscle) combining (by means of multiple regression analyses) to predict tenderness (panel ratings and shear values) with maximum precision. Neither total pigment concentration (a chemical measure of muscle color), amount of ether-extractable lipid (a chemical measure of intramuscular fatness) nor marbling score (a visual measure of intramuscular fatness) was able to explain more than about 7% of the observed variability in palatability ratings for cooked beef steaks. Data suggest that more attention should be paid to appearance of rib bones in a carcass (to better assess effects of maturity) and that less attention could be paid to differences between SLIGHT, SMALL and MODEST in marbling in the ribeyes, in attempting to predict, via USDA grading, the palatability of beef rib steaks.     

Performance of cold-set binding agents in re-formed beef steaks

Four cold-setting gel-forming binding agents were compared in preparation of re-formed steaks from strips of each of two muscles, M. triceps brachii-caput longum (TB) from the shoulder, and M. pectoralis profundus (PP) from the brisket, of steer forequarter. The binding agents, which were commercial preparations, were Activa, containing transglutaminase enzyme as active ingredient, Fibrimex, containing the blood plasma fractions fibrinogen and thrombin, Textor, containing a modified starch, and alginate, containing sodium alginate and Ca⁺⁺. Binding of the cooked steaks and of slices therefrom, was satisfactory for the first three of the above but relatively weak for the alginate agent. Colour of steaks was affected by binder, in that Activa and Textor treatments gave lighter, redder and yellower (higher L∗, a∗, b∗ values) steaks than did the other two. Overall acceptability ratings by taste panels corresponded with those for flavour in the case of TB steaks, with Activa and Fibrimex samples scoring highest (P < 0.05). For the less tender PP steaks, the highest acceptability score was for the Textor samples, reflecting their scoring best for tenderness. Warner–Bratzler shear force values corresponded with tenderness ratings in that Textor samples had lowest shear values for both muscles, but the differences were not significant. The overall conclusion, considering cohesion, appearance, cooking yield and sensory quality of the products, was that the Activa binder performed best and would facilitate the production of good-quality chilled re-formed beef steaks from various low-value beef muscles, and without addition of sodium chloride if so desired.     

Retail display evaluation of steaks from select beef strip loins injected with a brine containing 1% ammonium hydroxide. Part 2: Cook yield, tenderness, and sensory attributes

The impact of 2 different brines on the palatability and tenderness of select beef strip loin steaks was evaluated. Brines were differentiated by the type of alkaline agent, 4.5% sodium-based phosphate (control brine; CON) or 1% ammonium hydroxide (ammonium hydroxide treatment; AHT), incorporated into the formula. Injected steaks were placed in high oxygen (80% O(2)/20% CO(2)) MAP, stored 4 d at 4 °C in dark storage to simulate transportation, and then placed in retail display. Steaks were selected randomly on day 0, 7, and 14 retail display to measure pH, cook loss, shear force, and sensory characteristics. The pH for AHT steaks (pH 5.96) was slightly higher than CON steaks (pH 5.86; P < 0.05). Cook loss was lower (21%) for CON than AHT steaks (23%). There was neither a treatment nor day effect on tenderness as measured by Warner-Braztler shear force (P > 0.05). Sensory evaluation indicated that on day 0, retail display the initial juiciness, sustained juiciness, tenderness 1st impression, tenderness overall impression, and connective tissue in AHT steaks was not different from CON steaks (P > 0.05). A day effect (decrease) for those sensory parameters was observed only for sustained juiciness (P < 0.05). AHT steaks were rated higher in cooked beef flavor while CON steaks were higher in peppery and salty flavor. There was no difference in soapy and ammonia intensity between treatments. Results indicated that despite lower performance in cook loss the replacement of 4.5% sodium-based phosphate in a meat injection brine with 1% ammonium hydroxide produced a beef loin steak with comparable tenderness and palatability. Practical Application: The research in this study compares steaks that have been injected with a commercial brine formulated with sodium phosphates to steaks that have been injected with a brine where the sodium phosphate in the formulation was replaced with 1% ammonium hydroxide. Ammonium hydroxide is an USDA-FSIS approved ingredient in brines injected into fresh meats. Successful replacement of sodium phosphate with ammonium hydroxide would allow processors to significantly reduce the sodium content of injected fresh meat.     

Effects of Phage Concentration, Bacterial Density, and Temperature on Phage Control of Beef Spoilage

Retail beef steaks, inoculated with graded amounts of a Pseudomonas spp. and homologous phage, were subjected to a range of retail case temperatures to assess the significance of any interactive effects upon retail case life. The potential of phage to increase the case life of beef was unaffected by temperature within the range 1–10°C but was significantly influenced by the interactive effects of initial bacterial density and phage concentration. A maximum increase in the retail case life of beef, from 3.4 to 6.4 days, required initial bacterial densities of 4.6 × 10³ CFU/cm² and phage concentration of 9.7 × 10⁷ PFU/ cm².     

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.     

Effect of Muscle Type and Mixing Time on Sectioned and Formed Beef Steaks

Sectioned and formed beef steaks were manufactured from Standard beef rounds, Choice beef plates and Choice, Yield Grade 3, Meat Buyers Guide (126) 3-piece chucks. Replicates were established by slaughter day. A trained sensory panel evaluated juiciness, flavor, tenderness, and connective tissue residue. Color scores were assigned to steaks from each treatment. Instron Kramer shear was used to evaluate tenderness and thiobarbituric acid (TBA) was used to measure rancidity. Reflectance spectrophotometry indicated oxymyoglobin and metmyoglobin content. Mixing improved tenderness (P < 0.01) by 20% after 18 min. An 8% improvement occurred after 6 min. Mixing increased sensory juiciness (P < 0.01) and flavor (P < 0.05). Subjective and objective measures indicated that steaks processed from chuck were less tender (P < 0.01). Cooking yields improved linearly (P < 0.01) due to mixing. The TBA values were low and did not change due to treatment or after 90 days storage at –30°C. Subjective and objective color analyses indicated highly desirable color for fresh beef. Steaks processed from chuck meat were higher in percent metmyoglobin.     

INCREASING THE TENDERNESS OF BULLOCK BEEF BY USE OF ANTEMORTEM ENZYME INJECTION

Steaks from 58 beef carcasses were used to determine the effects of antemortem injections of proteolytic enzyme in increasing tenderness and/or in reducing tenderness variability among bullock carcasses. Sensory panel ratings indicated that steaks from the carcasses of treated bullocks did not differ significantly from steaks from treated steer carcasses in tenderness or overall satisfaction, but were significantly more tender and satisfactory overall than steaks from untreated bullocks. Variation in tenderness scores within the group of steaks from treated bullocks was reduced to a level more nearly comparable to that of steaks from treated steers. Since antemortem injections of papain increased tenderness and reduced the variability in tenderness among steaks from bullock carcasses, such treatment could be used to more effectively merchandise beef from young bulls.     

Vacuum Mixing Influence on Characteristics of Sectioned and Formed Beef Steak

Choice, Yield Grade 3 chucks were purchased vacuum packaged within 48 hr of slaughter. They were randomly allocated to treatments of vacuum or no vacuum mixing and 6 or 12 min mixing periods. The meat was formulated into sectioned and formed steaks. A trained sensory panel evaluated all samples and color scores were assigned to each steak. Instron adhesion measured binding of meat pieces, Kramer shear indicated tenderness, mg exudate/cm² measured binding proteins. Reflectance spectrophotometry measured oxymyoglobin and metmyoglobin. Electrophoresis was used to separate and quantitate individual myofibrillar proteins. Sensory analyses indicated vacuum processed steaks had superior bind (P < 0.01) while juiciness, flavor and tenderness remained unchanged. Instron analyses indicated no difference in tenderness or bind strength due to vacuum. Subjective color analyses indicated less desirable color for vacuum mixing (P < 0.05) and the amount of oxymyoglobin and metmyoglobin were not changed due to treatment. There was less exudate at the bond site for vacuum mixing (P < 0.01). Sarcoplasmic and myofibrillar proteins were similar over vacuum treatment.     

Physical and sensory characterization and consumer preference of corn and barley-fed beef

Steaks from corn-fed and barley-fed beef were characterized by a trained panel, which rated corn-fed beef higher (p<0.05) for tenderness attributes and overall flavor intensity. Canadian consumers preferred (p<0.01) cooked and raw steaks from barley-fed beef, while Mexican consumers showed no preference (p>0.05) for either type of finished beef. Japanese consumers showed a preference (p<0.05) for the appearance of raw barley-fed steaks but a preference for cooked corn-fed steaks (p<0.05). No differences (p>0.05) were observed for Warner-Bratzler shear, marbling scores, cooking losses or Hunter colorimeter values. There was a trend for higher concentrations (p<0.08) of the saturated fatty acids in the barley treatment, but no differences (p>0.10) in mono or polyunsaturated fatty acids.     

APPLICATION OF ACTINIDIN FROM KIWIFRUIT TO MEAT TENDERIZATION AND CHARACTERIZATION OF BEEF MUSCLE PROTEIN HYDROLYSIS

The effect of actinidin on the tenderness of broiled bovine semitendinosus (ST) steaks was studied. An actinidin activity of 400 U/mL resulted in Kramer shear values and sensory tenderness scores equivalent to that produced by Adolph's papain-based meat tenderizer (18 U/mL). Both were significantly (P<0.05) more tender than steaks having no tenderizing treatment. Actinidin did not over-tenderize the steak surface as did Adolph's meat tenderizer. Hydrolysis of myofibrillar proteins in enzyme-treated steaks prior to broiling was considerably less for actinidin than for papain when using activities to attain equal Kramer shear values of broiled steaks.     

Effects of moisture enhancement, enzyme treatment, and blade tenderization on the processing characteristics and tenderness of beef semimembranosus steaks

The individual and combined effects of moisture enhancement with a salt/phosphate solution (ME), blade tenderization (BT), and enzyme injection with proteinases derived from Aspergillus oryzae or Bacillus subtilis on cooking properties, Warner-Bratzler shear force (WBSF), and sensory characteristics of beef semimembranosus were investigated. ME significantly (P < 0.01) reduced WBSF and increased (P < 0.05) sensory scores for juiciness and tenderness. BT increased (P < 0.05) initial and overall tenderness scores and made connective tissue less perceptible. BT combined with ME resulted in the highest initial and overall tenderness scores, however, combining ME with either proteinase was as effective for reducing WBSF and increasing tenderness, particularly at 20 (vs. 10) ppm enzyme inclusion. Tenderness of enzyme-injected steaks was increased without compromising other palatability attributes. All treatments increased the frequency of steaks rated slightly tender or higher, with the ME+BT combination, or ME with inclusion of 20 ppm of either proteinase, being most effective.     

几种牛肉嫩化方法的研究

采用正交实验方法和感官评定方法来优化和评价氯化钙溶液注射、生姜汁注射、木瓜蛋白酶溶液注射对牛肉嫩度等的影响。实验结果表明,氯化钙溶液的浓度和注射量、生姜汁的注射量、木瓜蛋白酶溶液的浓度和处理时间显著影响牛肉的嫩度(P<0.05)。     

The effects of high oxygen modified atmosphere packaging on protein oxidation of bovine M. longissimus dorsi muscle during chilled storage

Modified atmosphere packaging (MAP) extends the shelf life of beef, especially in the context of visual colour. High O₂ MAP (70-80%) may cause quality deterioration through lipid and protein oxidation, the latter linked to a reduction in meat tenderness. The objective of this study was to investigate the effects of MAP in comparison to vacuum packaging (VP) on protein oxidation and subsequent tenderness of LD (M. longissimus dorsi) beef steaks during chilled storage (4 °C) of periods up to 14 days. Steaks were analysed for carbonyl content, free thiol groups, drip loss, Warner-Bratzler shear force (WBSF) and SDS-PAGE of extracted myofibrillar proteins. Free thiol groups were lower in high O₂ MAP (80% O₂/20% CO₂) steaks, after 14 days of storage, indicating protein oxidation compared to VP steaks. SDS-PAGE (non reducing conditions) showed the presence of high molecular weight cross linked myosin heavy chain aggregates in the high O₂ atmosphere packaged steaks, which were absent in VP steaks.