D.D. Johnson

Muscle profiling: Characterizing the muscles of the beef chuck and round.

To fully characterize properties of the muscles of the beef chuck and round, and to reveal potential opportunities to upgrade the value, 39 different muscles were dissected from 142 beef carcasses differing in carcass weight, yield grade, and quality grade. Numerous physical and chemical properties of the muscles were determined. Muscle effects were observed for all traits (objective color, expressible moisture, proximate composition, emulsion capacity, pH, total collagen content, total heme-iron concentration, and Warner-Bratzler shear force). USDA quality grade generally had the most effect on muscle traits, with carcass weight and yield grade having lesser effects. These muscle profile data will allow for more informed decisions to be made in the selection of individual muscles from the beef chuck and round for the production of value-added products.

National beef tenderness survey – 2006: Assessment of Warner–Bratzler shear and sensory panel ratings for beef from US retail and foodservice establishments

Beef from retail and foodservice establishments in 11 US cities was evaluated using Warner-Bratzler shear (WBS) and consumer evaluation panels. Postmortem aging times ranged from 3 to 83d for retail and 7 to 136d for foodservice with mean aging times of 22.6d and 30.1d, respectively. For retail, the three cuts from the round - top round, bottom round, and eye of round - had the highest (P<0.05) WBS values compared to cuts from the chuck, rib, and loin. Top loin steaks had the lowest (P<0.05) WBS value compared to ribeye and top sirloin foodservice steaks. Retail bone-in top loin, top loin, ribeye, T-bone, and porterhouse received the highest (P<0.05) ratings by consumers for overall like and like tenderness. Quality grade had little or no effect on foodservice sensory evaluations. Improvements in round tenderness are needed to increase consumer acceptability.

Breed type and sex effects on carcass traits, composition and tenderness of young goats

Abstract Seventy-five goats of three breed groups (Florida native (FN), Nubian × Florida native (NF), Spanish × Florida native (SF)) and three sex classes (female, intact male, castrate) were used to study factors affecting carcass and meat characteristics. Goats were fed predominantly a forage diet and slaughtered at the Meat Science Laboratory, Gainesville, FL. NF crosses had the heaviest slaughter and carcass weights when compared to the other breed types. Dressing percentage and individual dress-off items were not affected by breed. Breed type had very little effect on carcass quality and yield indicators. Carcasses from FN goats had higher percentages of fat and lower percentages of bone than did NF or SF carcasses. Breed type did not affect percentage fat-free lean in the side or fat-free lean to bone ratio. Breed type had no effect on Warner-Bratzler shear (WBS) values for muscles from the leg and loin. In contrast, female goats had lower percentages of feet, pelt, liver, heart and kidney when compared to the other sex classes. Male carcasses had softer flank firmness, less marbling but lighter lean color scores than did castrate or female carcasses. Male carcasses had less actual and adjusted fat opposite the ribeye and less estimated kidney and pelvic fat. Sides from male goats had less fat and more fat-free lean than did castrate or female carcasses. Castrates had the lowest fat-free lean to bone ratio of the three sex classes. WBS values from female carcasses indicated more tender muscles than from castrate or intact male carcasses. This study suggested that sex class had a greater influence on carcass characteristics than did breed type.

Diet/management effects on carcass attributes and meat quality of young goats1

Abstract Thirty-seven goats were produced and raised in either an intensive (I) or semi-intensive (S) diet/management system, then slaughtered at 8 months of age. Goats from the I group had heavier slaughter and carcass weights, higher dressing percentages and larger longissimus cross-sectional areas than goats produced under the S system. Carcass composition (fat, bone or fat-free lean) was not affected by diet/management system. Carcasses from the I goats had firmer flanks, more flank fat streakings and slightly coarser lean texture than carcasses from S goats. Other indicators of carcass quality were not affected by diet/management. Diet/management treatment had no influence on sensory panel evaluation of roasted loins nor Warner–Bratzler shear evaluation of grilled leg slices. Lean and fat [composite samples from the dissected side of I goat carcasses] had a higher percentage of saturated and polyunsaturated fatty acids than composite samples from the S goat carcasses. Goat carcasses from the S system had a higher ratio of unsaturated to saturated fatty acids for a composite sample from one side compared to composite samples from goat carcasses produced in the I system. Although the I system did improve live and slaughter weights and increase dressing percentages, it had little effect on palatability traits and therefore could not be justified based on improving carcass quality attributes. The practicality of the I system for rearing goats and the corresponding improved yield would depend on production costs.

The effects of quality grade, aging, and location within muscle on Warner–Bratzler shear force in beef muscles of locomotion

Aging patterns of nine muscles from the chuck and round from two quality classifications of beef: USDA Select and upper 2/3 of USDA Choice grade were determined. The following muscles were evaluated: infraspinatus, triceps brachii - lateral head, triceps brachii - long head, serratus ventralis, complexus, splenius, rhomboideus, vastus lateralis and rectus femoris. Muscles were divided into four portions, progressing from anterior to posterior or dorsal to ventral orientation to the carcass depending on muscle fiber orientation. One steak was removed from each portion and aged for 7, 14, 21, or 28 d postmortem, then Warner-Bratzler shear force (WBSF) analysis was conducted. Consistent aging recommendations can be given for all muscles studied, as there was no aging by muscle interaction. An aging by USDA grade interaction was noted (P<0.05). The upper 2/3 of USDA Choice need not be aged beyond 7 d. USDA Select should be aged at least 14 d. Steak location within muscle had an effect (P<0.05) on WBSF values in four muscles. These data indicate that fabrication and merchandizing decisions should be made on an individual muscle basis.

Determination of sensory, chemical and cooking characteristics of retail beef cuts differing in intramuscular and external fat

Top loin (TLS), top sirloin (TSS), and eye of round (EYS) steaks, and loin end (LRR) and blade end (BRR) rib, and eye of round (EYR) roasts were used to determine the effect of USDA quality grade, Choice or Select, external fat trim level, and internal temperature endpoint on sensory, chemical and cooking characteristics. Cuts cooked with external fat required slightly greater cooking times and had higher fat content in the lean than cuts cooked without external fat (p < 0.05). Regardless of quality grade or external fat trim, increasing internal temperature endpoint resulted in tougher, drier cuts with longer cooking times and greater cooking loss (p < 0.05). Choice TLS, TSS and LRR were higher (p < 0.05) in palatability than Select, but quality grade did not affect palatability of BRR, EYS or EYR.

National Beef Tenderness Survey–2010: Warner-Bratzler shear force values and sensory panel ratings for beef steaks from United States retail and food service establishments

The tenderness and palatability of retail and food service beef steaks from across the United States (12 cities for retail, 5 cities for food service) were evaluated using Warner-Bratzler shear (WBS) and consumer sensory panels. Subprimal postfabrication storage or aging times at retail establishments averaged 20.5 d with a range of 1 to 358 d, whereas postfabrication times at the food service level revealed an average time of 28.1 d with a range of 9 to 67 d. Approximately 64% of retail steaks were labeled with a packer/processor or store brand. For retail, top blade had among the lowest (P < 0.05) WBS values, whereas steaks from the round had the greatest (P < 0.05) values. There were no differences (P > 0.05) in WBS values between moist-heat and dry-heat cookery methods for the top round and bottom round steaks or between enhanced (contained salt or phosphate solution) or nonenhanced steaks. Food service top loin and rib eye steaks had the lowest (P < 0.05) WBS values compared with top sirloin steaks. Retail top blade steaks and food service top loin steaks received among the greatest (P < 0.05) consumer sensory panel ratings compared with the other steaks evaluated. Prime food service rib eye steaks received the greatest ratings (P < 0.05) for overall like, like tenderness, tenderness level, like juiciness, and juiciness level, whereas ungraded rib eye steaks received the lowest ratings (P < 0.05) for like tenderness and tenderness level. The WBS values for food service steaks were greater (P < 0.05) for the Select and ungraded groups compared with the Prime, Top Choice, and Low Choice groups. The WBS values and sensory ratings were comparable to the last survey, signifying that no recent or substantive changes in tenderness have occurred.

Enhancing palatability traits in beef chuck muscles.

Thirty-six USDA Select complexus, latissimus dorsi, rhomboideus, serratus ventralis (SEV), splenius, subscapularis, supraspinatus (SUS), and triceps brachii (TRB) muscles were studied. Muscles were assigned to one of four treatments: control, marinated, needle-pumped, and vacuum-tumbled to reach 10% brine pick-up after treatment. The solution was formulated to have 0.5% of sodium chloride and 0.4% of sodium tripolyphosphate in the end product. Steaks from the SEV, SUS, and TRB muscles were cooked on a grill and the other five muscles were oven-roasted whole, all of them cooked to an internal temperature of 71°C. Sensory evaluations and Warner-Bratzler shear force (WBSF) determinations were conducted immediately after cooking (Day-1), and after being cooked and stored frozen for 60 days (Day-60). For the Day-60 evaluation, samples were reheated using a microwave oven. The needle-pumped treatment reduced WBSF values compared to the control in 3 out of 8 muscles (P<0.05). The marinated treatment appeared to have the greatest influence on juiciness and was different from the control in 7 of 8 muscles (P<0.05). Comparing treated muscles to the control, tenderness was increased in 4 out of 8 muscles when needle pumped (P<0.05). Brine treatment reduced sensory detected connective tissue only in 2 of 8 muscles. More off-flavors were detected by the panel for marinated samples from six of eight muscles. All muscles had lower values for WBSF, less connective tissue and off-flavors, and higher juiciness, overall tenderness, and beef flavor intensity on Day-1 than Day-60. The needle-pumped method was slightly superior to the marinated and vacuum-tumbled treatments even though the differences were not always consistent. But, regardless of the application method, palatability traits were generally enhanced by brine treatments.

Chemical properties of cow and beef muscles: benchmarking the differences and similarities.

The objective of this study was to identify muscles from cow populations that are equivalent or may possibly be made equivalent to muscles from A-maturity, Select-grade cattle in terms of chemical, compositional, and color characteristics. Objective color, expressible moisture, proximate composition, pH, heme iron concentration, and total collagen content were determined for 9 muscles (M. gluteus medius, M. infraspinatus, M. longissimus dorsi, M. psoas major, M. rectus femoris, M. tensor fascia latae, M. teres major, M. triceps brachii lateral-head, and M. triceps brachii long-head) from 15 cattle from each of 5 commercially identified populations [fed beef cows (B-F), non-fed beef cows (B-NF), fed dairy cows (D-F), non-fed dairy cows (D-NF), and A-maturity, Select-grade cattle (SEL)]. Muscles from B-F and B-NF populations were more similar to the SEL than were the D-F and D-NF. There were 2 muscles, the M. infraspinatus and M. teres major, from the population of B-F that were similar, physically and chemically, to SEL in most traits. The majority of the 9 muscles from the cows did not differ (P < 0.05) from SEL for percentage expressible moisture, proximate composition, and total collagen content. However, notable differences in pH, objective color L*, total pigment content, and heme iron content existed between cow populations and SEL. The muscles from SEL had significantly (P < 0.05) lower total pigment and heme iron concentrations. These differences likely relate to the visual appearance of muscles from the different populations of cattle. Two of the 9 muscles studied were similar among cow populations and A-maturity, Select-grade beef.

Factors influencing tenderness in steaks from Brahman cattle

The objective of this study was to identify a set of explanatory variables for Warner-Bratzler shear force and myofibril fragmentation indices after 7, 14, and 21d of aging; and sensory tenderness after 14d of aging of steaks from Brahman cattle. Insoluble collagen was negatively associated (P<0.001) with all tenderness traits across aging periods, and regression coefficients ranged from 5.69±0.49 to 9.12±0.29N for Warner-Bratzler shear force. The effect of lean color score (P<0.05) in analyses of unadjusted traits was diminished when data were adjusted for contemporary group (calves of the same sex, fed in one pen, and slaughtered the same day). Insoluble collagen may be of special importance and offer a unique opportunity to improve palatability of steaks from purebred Brahman cattle.