Gluteus Medius Steaks Research Articles

Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on strip loin steak dimensionality, shear force, and sensory attributes.

Carcasses (n = 115) from steers resulting from the mating of four Limousin × Angus sires heterozygous for the F94L myostatin mutation to Jersey, Jersey × Holstein, and Holstein dams were utilized to evaluate the effects of one copy of the F94L allele on strip loin dimensionality, Warner-Bratzler shear force and slice shear force, and sensory panel ratings. In Phase I of a two-phase study, 57 carcasses from two sires were utilized to obtain samples of longissimus dorsi (LD), psoas major (PM), gluteus medius (GM), semitendinosus (ST), serratus ventralis (SV), triceps brachii (TB), and biceps femoris (BF) muscles, which were vacuum packaged, aged until 10 days postmortem, and frozen. Frozen strip loins were cut into 14 2.5-cm-thick steaks each, and individual strip loin steaks were imaged at a fixed height on a gridded background and processed through image analysis software. In Phase II, to obtain a greater power of test for LD palatability attributes, 58 additional carcasses from 3 sires were utilized to obtain LD samples only for sensory panel and shear force analysis. Cooked steak sensory attributes evaluated by trained panelists were tenderness, juiciness, beef flavor, browned flavor, roasted flavor, umami flavor, metallic flavor, fat-like flavor, buttery flavor, sour flavor, oxidized flavor, and liver-like flavor. In strip loin steaks from carcasses with one F94L allele, LD muscle area was larger in steaks 4, 5, 7, 8, and 9, and steaks 1, 6, 7, and 9 were less angular than those from carcasses with no F94L allele (P < 0.05). Of the seven muscles observed, there were no shear force differences between F94L genotypes (P > 0.20). F94L genotype did not affect sensory panel ratings of LD and GM steaks (P > 0.07). Cooked ST steaks from carcasses with one F94L rated lower in fat-like flavor compared to those from carcasses with no F94L allele (P = 0.035). Cooked PM steaks from carcasses with one F94L allele rated lower in juiciness, fat-like flavor, buttery flavor, and umami flavor compared to those with no copies of the F94L (P < 0.04). In summary, one copy of the F94L allele utilized in beef × dairy cross steers improved strip loin steak dimensionality, did not affect cooked steak tenderness across seven muscles, and decreased fat-associated flavors in the PM and ST. Use of F94L homozygous terminal beef sires would be an easily implemented strategy for dairy producers to improve steak portion size and shape in carcasses from non-replacement calves.

Extended Aging and Marbling Class Effects on Color Stability of Beef Longissimus lumborum, Gluteus medius, and Biceps femoris Steaks

Postmortem aging improves palatability of various muscles, especially those from lower quality grades. This study evaluated postmortem aging and marbling class effects on the color stability of longissimus lumborum, gluteus medius, and biceps femoris steaks. Carcasses were selected at grading to have Lower Small (Small00 to Small50; n = 50) or Upper Slight (Slight50 to Slight90; n = 50) marbling scores. Strip loin and top sirloin subprimals from each carcass side were assigned to aging treatments (14, 21, 28, or 35 d) in an incomplete block arrangement. After aging, subprimals were cut into longissimus lumborum, gluteus medius, and biceps femoris steaks, respectively. Steaks were placed in a simulated retail display for 11 d. Changes in redness (a* and hue angle) were much slower and less extensive (P &amp;lt; 0.001) in longissimus lumborum steaks than in gluteus medius steaks, which had slightly slower and less extensive (P &amp;lt; 0.01) redness changes than biceps femoris. Increasing aging time increased (P &amp;lt; 0.001) the rate and extent of overall color change (ΔE) during simulated retail display. Steaks from Lower Small carcasses had higher (P &amp;lt; 0.01) L* values than steaks from Upper Slight carcasses at 14, 28, and 35 d postmortem. In steaks from Upper Slight carcasses, L* values were lower (P &amp;lt; 0.01) in steaks aged for 28 d compared to other aging times. In steaks from Lower Small carcasses, L* values were highest (P &amp;lt; 0.001) when aged for 14 d. Increased aging time generally decreased (P &amp;lt; 0.05) a*, b*, and chroma values. However, within each aging time, only b* values of steaks aged for 35 d differed (P = 0.01) with regard to marbling class. Results indicate that increasing aging time decreased color life of beef muscles, and that marbling class had minimal impact on lean color stability.

Postmortem Aging Time and Marbling Class Effects on Flavor of Three Muscles From Beef Top Loin and Top Sirloin Subprimals

This study evaluated postmortem aging time and marbling class effects on flavor attributes of longissimus lumborum, gluteus medius, and biceps femoris steaks. Carcasses selected to have Lower Small (Small00 to Small49; n = 50) or Upper Slight (Slight50 to Slight99; n = 50) marbling were assigned to aging treatments (14, 21, 28, or 35 d) in an incomplete block arrangement. A trained sensory panel evaluated longissimus lumborum, gluteus medius, and biceps femoris steaks for tenderness, juiciness, and 31 flavor notes. Tenderness increases with aging time were linear (P &amp;lt; 0.001) in longissimus lumborum and gluteus medius steaks and quadratic (P = 0.001) in biceps femoris steaks. Aging response of rancid flavor in longissimus lumborum steaks was cubic (P = 0.01), whereas the aging response of bloody/serumy flavor in biceps femoris steaks was quadratic (P = 0.03). Compared with Upper Slight marbling, carcasses with Lower Small marbling produced longissimus lumborum steaks with greater (P &amp;lt; 0.01) beef flavor and lesser (P = 0.001) bitter flavor, gluteus medius steaks with greater (P = 0.05) brown/roasted flavor, and biceps femoris steaks with greater (P = 0.02) fat-like flavor, although differences were small. Principal component analysis indicated that bloody/serumy, sour, metallic, and bitter flavor attributes were the strongest contributors to a factor explaining 38% of longissimus lumborum flavor variation. Barnyard, bitter, sour, rancid, and bloody/serumy were the greatest contributors to a principal component explaining 41% of gluteus medius flavor. Barnyard, rancid, sour, bloody/serumy, and bitter were contributors to a component explaining 63% of biceps femoris sirloin cap flavor variance. Sample score plots indicated that neither aging time nor marbling class was associated with principal components and identified production lot as contributing to principal components explaining flavor variation in all 3 muscles. Results indicate that, in strip loin and top sirloin subprimals from carcasses with Upper Slight and Lower Small marbling scores, aging time and marbling class had little impact on beef flavor. Thus, increased aging times could be used to enhance tenderness with no adverse effects on other important palatability attributes.

25 Cooking method and muscle type impact volatile compound development in beef steaks

Abstract The objective of this study was to determine the influence of dry heat cookery on beef flavor development of multiple beef muscles. Beef strip loins, top sirloin butts, tenderloins, shoulder clods, and chuck rolls were collected from USDA Low Choice carcasses (Small00-Small100 marbling; n = 20). Subprimals were wet aged in the dark for 21 d at 0 - 4℃. Following aging, subprimals were fabricated into 2.54 cm thick steaks of the following muscles: Gluteus medius (GM), Infraspinatus (IF), Longissimus lumborum (LL\), Psoas major (PM), Serratus ventralis (SV), and Triceps brachii (TB). Steaks were cooked to a medium degree of doneness (71℃) on one of four randomly assigned cooking methods: charbroiler grill (CHAR), clamshell grill (CLAM), convection oven (OVEN), or salamander broiler (SALA). Volatile compound analysis was conducted using gas chromatography-mass spectrometry with solid phase microextraction. Data were analyzed as a split plot arrangement, with subprimal serving as the whole plot factor and cooking method serving as the subplot factor. The majority of compounds evaluated were impacted by the cooking method main effect (n = 21), followed by the cooking method × muscle interaction (n = 18), and muscle (n = 12). Charbroiler GM steaks produced the greatest amount of methional, 2,5-dimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine, and 2-ethyl-3,5-dimethylpyrazine compared to all other treatments (P &amp;lt; 0.05). Charbroiler and CLAM steaks produced the greatest concentration of methylpyrazine and trimethylpyrazine, as well as Strecker aldehydes (P &amp;lt; 0.05), indicating that more direct applications of heat increased Maillard product production. Steaks cooked using OVEN and SALA produced more lipid oxidation products, such as alkanes, aldehydes, and lipid derived ketones. Gluteus medius and SV steaks produced the greatest concentration of volatile compounds, with SV steaks producing an increased concentration of lipid derived compounds (P &amp;lt; 0.05) and GM steaks producing a greater concentration of Maillard products (P &amp;lt; 0.05). These data indicate that cooking method has a direct impact on the flavor profile produced by steaks.

Chemical Characterization and Sensory Relationships of Beef M. longissimus lumborum and M. gluteus medius Steaks After Retail Display in Various Packaging Environments

Volatile compounds, carbonyls, non-heme iron, and thiobarbituric acid reactive substances (TBARS) were measured in both raw and cooked beef samples to determine the effects of muscle and packaging type on beef flavor development. All paired strip loins and top sirloin butts were packaged under vacuum and aged for 14 d postmortem. After initial aging, all subprimals were fabricated to produce M. gluteus medius (GM) or M. longissimus lumborum (LL) steaks. At 14 d postmortem, steaks were randomly assigned to 1 of 5 package types: high-oxygen modified atmosphere lidded trays (80% O2/20% CO2 [“HIOX”]), carbon monoxide modified atmosphere lidded trays (0.4% CO/30% CO2/69.6% N2 [“CO”]), rollstock (forming and non-forming films [“ROLL”]), vacuum packaging without retail display (“VAC”), and traditional overwrap (“OW”) remained under vacuum prior to retail display. Steaks were stored in darkness an additional 7 d prior to display. At 21 d postmortem, HIOX, OW, CO, and ROLL packages were displayed for 48 h under continuous fluorescent lighting, while VAC steaks remained in dark storage. Packaging and muscle type impacted (P &amp;lt; 0.05) quantities of multiple volatile flavor compounds, including alcohols, n-aldehydes, esters, furans, hydrocarbons, sulfur-containing compounds,and ketones in both raw and cooked samples. Volatile compounds related to lipid oxidation were more (P &amp;lt; 0.05) prominent in HIOX packaging. Package type (P &amp;lt; 0.05) and muscle (P &amp;lt; 0.05) had an impact on raw-steak TBARS, although package type did not influence (P &amp;gt; 0.05) cooked-steak TBARS. The GM possessed greater (P &amp;lt; 0.05) TBARS values than the LL in both raw and cooked samples. Package type had no effect (P &amp;gt; 0.05) on carbonyl and non-heme iron content although these analyses differed among muscles (P &amp;lt; 0.05), with the GM being greater (P &amp;lt; 0.05) than the LL. These results indicate that the development of lipid oxidation that occurs during storage and display was muscle and packaging specific. Therefore, to maintain flavor, quality packaging systems should be selected on a muscle-specific basis.

Impact of Packaging and Muscle Type on Beef Flavor Development

ObjectivesThe objective of this study was to determine the influence of packaging type on production of beef flavor volatile compounds.Materials and MethodsBeef strip loins (IMPS #180) and top sirloin butts (IMPS #184) were selected from USDA Low Choice carcasses (n = 40, 20/subprimal). Seven d postmortem, subprimals were fabricated into 2.54 cm representative steaks of the Longissimus lumborum (LL) and Gluteus medius (GM). Steaks were then placed into one of four randomly assigned packaging treatments: carbon monoxide motherbag (0.4% CO/30% CO2/69.6% N2; CO), high oxygen modified atmosphere packaging (80% O2/20% CO2; HIOX), traditional polyvinyl chloride overwrap (OW), and rollstock (ROLL). Steaks designated for the OW treatment were placed in ROLL treatment until retail display. Steaks were aged in the absence of light for 14 d, then subjected to a 48-h retail display under fluorescent lighting in coffin cases. Following retail display, steaks were immediately vacuum packaged and frozen at –20°C until further analysis. Prior to volatile compound analysis, steaks were thawed at 2–4°C. Steaks were then cooked to 71°C using clamshell grills. Immediately after cooking, six 1.27 cm cores were removed, then minced using a coffee grinder. Five g of sample was weighed into a glass vial, sealed, then analyzed using gas chromatography-mass spectrometry. Compounds evaluated were chosen from major flavor pathways.ResultsThree compounds, carbon disulfide, 2-pentylfuran, and benzaldehyde elicited a packaging type × muscle interaction (P ≤ 0.048). Carbon disulfide was present in the highest concentration (P &lt; 0.05) in CO GM and ROLL LL steaks, but was present in the lowest amount (P &lt; 0.05) in OW GM and ROLL GM steaks. For benzaldehyde, HIOX GM steaks produced the greatest concentration (P &lt; 0.05) compared to all other treatments, with the exception of ROLL LL, which was similar (P &gt; 0.05). A similar trend existed for 2-pentylfuran, as high oxygen GM steaks produced over three times higher concentrations (P &lt; 0.05) of 2-pentylfuran compared to all other treatments. Nine compounds, primarily lipid derived, were impacted by a packaging main effect (P &lt; 0.043). For 2-propanone, pentane, and hexanoic acid, methyl ester, HIOX packaging produced the greatest concentration (P &lt; 0.05) compared to all other treatments. Additionally, HIOX steaks produced a greater amount (P &lt; 0.05) of methanethiol than OW or ROLL steaks. High oxygen steaks produced more (P &lt; 0.05) 1-pentanol, 1-octen-3-ol, and nonanal than CO steaks, but were similar to ROLL and OW steaks. Carbon monoxide packaging produced the greatest amount (P &lt; 0.05) of 2,3-butanediol compared to all other treatments. Five compounds were impacted by the muscle main effect (P ≤ 0.039). The GM steaks produced a greater concentration of 2,3-butanedione (P = 0.011), 3-hydroxy-2-butanone (P = 0.002), octanoic acid (P &lt; 0.001), and dodecanal (P = 0.021) than the LL steaks. The LL produced a greater amount of decanal (P = 0.039) than the GM.ConclusionThese results indicate packaging and muscle each impact flavor, however, packaging effects are primarily lipid derived and muscle more readily impacts Maillard product production. Additionally, HIOX packaging produces a large amount of lipid derived compounds from degradation and oxidation, which may form the basis for its negative flavor profile. This indicates HIOX packaging should be avoided to produce more positive flavor notes in beef.

Impact of Packaging and Muscle Type on Beef Flavor Development

ObjectivesThe objective of this study was to determine the influence of packaging type on production of beef flavor volatile compounds.Materials and MethodsBeef strip loins (IMPS #180) and top sirloin butts (IMPS #184) were selected from USDA Low Choice carcasses (n = 40, 20/subprimal). Seven d postmortem, subprimals were fabricated into 2.54 cm representative steaks of the Longissimus lumborum (LL) and Gluteus medius (GM). Steaks were then placed into one of four randomly assigned packaging treatments: carbon monoxide motherbag (0.4% CO/30% CO2/69.6% N2; CO), high oxygen modified atmosphere packaging (80% O2/20% CO2; HIOX), traditional polyvinyl chloride overwrap (OW), and rollstock (ROLL). Steaks designated for the OW treatment were placed in ROLL treatment until retail display. Steaks were aged in the absence of light for 14 d, then subjected to a 48-h retail display under fluorescent lighting in coffin cases. Following retail display, steaks were immediately vacuum packaged and frozen at –20°C until further analysis. Prior to volatile compound analysis, steaks were thawed at 2–4°C. Steaks were then cooked to 71°C using clamshell grills. Immediately after cooking, six 1.27 cm cores were removed, then minced using a coffee grinder. Five g of sample was weighed into a glass vial, sealed, then analyzed using gas chromatography-mass spectrometry. Compounds evaluated were chosen from major flavor pathways.ResultsThree compounds, carbon disulfide, 2-pentylfuran, and benzaldehyde elicited a packaging type × muscle interaction (P ≤ 0.048). Carbon disulfide was present in the highest concentration (P 0.05). A similar trend existed for 2-pentylfuran, as high oxygen GM steaks produced over three times higher concentrations (P < 0.05) of 2-pentylfuran compared to all other treatments. Nine compounds, primarily lipid derived, were impacted by a packaging main effect (P < 0.043). For 2-propanone, pentane, and hexanoic acid, methyl ester, HIOX packaging produced the greatest concentration (P < 0.05) compared to all other treatments. Additionally, HIOX steaks produced a greater amount (P < 0.05) of methanethiol than OW or ROLL steaks. High oxygen steaks produced more (P < 0.05) 1-pentanol, 1-octen-3-ol, and nonanal than CO steaks, but were similar to ROLL and OW steaks. Carbon monoxide packaging produced the greatest amount (P < 0.05) of 2,3-butanediol compared to all other treatments. Five compounds were impacted by the muscle main effect (P ≤ 0.039). The GM steaks produced a greater concentration of 2,3-butanedione (P = 0.011), 3-hydroxy-2-butanone (P = 0.002), octanoic acid (P < 0.001), and dodecanal (P = 0.021) than the LL steaks. The LL produced a greater amount of decanal (P = 0.039) than the GM.ConclusionThese results indicate packaging and muscle each impact flavor, however, packaging effects are primarily lipid derived and muscle more readily impacts Maillard product production. Additionally, HIOX packaging produces a large amount of lipid derived compounds from degradation and oxidation, which may form the basis for its negative flavor profile. This indicates HIOX packaging should be avoided to produce more positive flavor notes in beef.

Retail stability of three beef muscles from grass-, legume-, and feedlot-finished cattle.

This study aimed to determine the influence of finishing diet on beef appearance and lipid oxidation of three beef muscles. A total of 18 Angus steers were selected from three diet treatments: grass-finished (USUGrass), legume-finished (USUBFT), and grain-finished (USUGrain). After processing, longissimus thoracis (LT), triceps brachii (TB), and gluteus medius (GM) steaks were evaluated over a 7-d display period. A muscle × diet interaction was observed for instrumental lightness (L*) and redness (a*) (P ≤ 0.001). Within each combination, USUGrass was considered darker with lower (P < 0.05) L* compared with USUGrain. For USUBFT, L* was similar to USUGrain for the TB and LT, while the L* of USUBFT and USUGrain GM differed (P < 0.05). In terms of redness, LT a* values were elevated (P < 0.05) in USUGrass compared with USUBFT and USUGrain. For GM steaks, a* of USUBFT and USUGrass were each greater (P < 0.05) than USUGrain. Surface a* of TB steaks were greatest (P < 0.05) for USUGrass followed by USUBFT, and with USUGrain, being lowest (P < 0.05). An overall increase in L* was observed throughout display dependent on diet (P = 0.013). During display, USUGrain steaks had the greatest (P < 0.05) L* followed by USUBFT and USUGrass. Additionally, a day × muscle interaction was observed for a* (P = 0.009). Initially, TB steaks had the greatest (P < 0.05) a* values. However, at day 3, a* values were similar (P > 0.05) among muscles. Visual color scores were in agreement with loss of redness (a*) during display, dependent on diet and muscle type (P < 0.001). Similarly, a day × diet × muscle interaction was observed for visual discoloration (P < 0.001). Day and diet interacted to influence thiobarbituric acid reactive substances (TBARS) (P < 0.001). Initial values did not differ (P > 0.05) between USUGrain and USUBFT; however, USUGrass had lower initial (P < 0.05) TBARS than both USUGrain and USUBFT. At days 3 and 7, TBARS were greatest (P < 0.05) in USUGrain steaks, followed by USUBFT, which was greater (P < 0.05) than USUGrass. A diet × muscle interaction was observed for 10 volatile compounds originating from lipid degradation (P ≤ 0.013). These compounds were less (P < 0.05) abundant in USUGrass compared to TB or GM of USUGrain. This study determined grass-finished beef to have a darker more red color and less lipid oxidation in multiple muscles. Possible mechanisms for this may include an increase in endogenous antioxidants in grass-finished beef.

53 Impact of Packaging Types on Cooked Beef Volatile Flavor Compounds.

The objective of this study was to evaluate the impact of packaging type and muscle on beef volatile flavor compounds produced from grilling. Gluteus medius (GM) and Longissimus lumborum (LL) steaks were fabricated into 2.54 cm steaks and packaged in carbon monoxide modified atmosphere (CO), high oxygen (HIOX), polyvinyl chloride overwrap (OW), rollstock (ROLL), or vacuum (VAC) packaging and held for 7 days in dark storage. Steaks were then placed in retail coffin cases for 48 hours, except for VAC, which were held in darkness. Following the 48 hours, steaks were vacuum packaged and frozen at -20℃ until volatile compound analysis. Steaks were cooked to a medium degree of doneness (71℃) prior to analysis. Compounds evaluated were derived from various flavor development pathways, including Maillard reaction products and lipid derived compounds. Interactions between packaging type and muscle (P < 0.05) were observed for 2,3-pentanedione and 1-pentanol - two lipid derived compounds. Packaging significantly impacted lipid degradation products, as HIOX packaging possessed the greatest amount (P < 0.05) of 1-octen-3-ol, 1-octanol, dodecanal, nonane, pentane, tetradecane, 2-pentylfuran, 2-heptanone, 1-octene, and hexanoic acid, methyl ester when compared to all other packaging schemes. Contrastingly, ROLL packaging exhibited the greatest amount (P < 0.05) of 2-methy1-1-pentene and 2,4-dimethyl-1-heptene. For Maillard reaction products, HIOX possessed a greater amount of phenylacetaldehyde (P < 0.05) than ROLL and VAC treatments, but was similar (P > 0.05) to OW and CO. Dimethyl sulfide was present in the greatest amount (P < 0.05) in ROLL, VAC, and CO than HIOX and OW, which were similar (P > 0.05). When evaluating the impact of muscle on Maillard reaction products, LL steaks produced a greater amount (P < 0.05) of the Strecker aldehydes 3-methylbutanal and 2-methylbutanal than GM steaks. Similarly, LL steaks also produced a greater amount (P < 0.05) of methyl pyrazine, 2,5-dimethylpyrazine, and dimethyl sulfone. Contrastingly, GM steaks produced a greater amount (P < 0.05) of 2,3-butanedione, 3-hydroxy-2-butanone, and dimethyl sulfide than LL steaks when cooked. Within lipid derived compounds, LL steaks possessed a greater amount (P < 0.05) of ethanol and butryrolactone. However, GM steaks exhibited a greater amount (P < 0.05) of 2,3-butanediol and octanoic acid, which are indicators of lipid oxidation. These results suggest steaks in HIOX packaging undergo a greater amount of lipid oxidation in comparison to other packaging types. This could lead to detrimental effects of beef flavor when purchased by consumers.

358 Effects of rumen protected–histidine supplementation dose on finishing beef cattle

This study examined the effect of dietary rumen-protected histidine (HIS) supplementation in cattle on growth and carcass traits/product quality. Three levels of daily HIS (Balchem Corp.) were tested (control, low dose [DL], and high dose [DH]) over a 55-d finishing period in 48 crossbred steers implanted with Revalor-XS. Cattle were randomly allocated into 8 pens of 6 steers each and fed twice daily using Calan gates. Morning feed was top-dressed with the HIS as follows: control (no HIS), 50 g/steer per day (DL), or 100 g/steer per day (DH). Individual intakes were recorded, and feed and orts were analyzed every 5 d during the feeding period. Steers were harvested, carcass data was recorded, and carcasses were fabricated at a USDA-inspected facility. One longissimus lumborum (LL) and 1 gluteus medius (GM) was acquired from each animal, aged under vacuum (21 and 14 d respectively), and cut into 2.54-cm steaks. One steak was used for retail display for which subjective (to evaluate visual color components) and objective (L*, a*, and b*) color scores were recorded. Lipid oxidation on d 0 and 9 of retail display were assessed using thiobarbituric acid reactive substances. Another steak was used to evaluate cooking loss and tenderness using Warner–Bratzler shear force. Sensory taste panels were conducted (1 panel for each muscle) to determine consumer perception of the product. Muscles were analyzed using HPLC for HIS metabolite (anserine and carnosine) and HIS content. Histidine supplementation increased ADG during d 1 to 21 (DH, P = 0.07), d 42 to 60 (DL and DH, P = 0.07), and the final 50 d (DH, P = 0.07) of feeding. Supplementation with HIS also increased the lightness (DL GM, P = 0.05), degree of yellow hue (DL and DH LL, P = 0.01), oxygenated lean color (DL GM, P = 0.004), uniformity (DH GM, P = 0.03, and DH LL, P = 0.06), and overall color stability of the product from d 3 through 9 of retail display. The percent surface discoloration (DL and DH GM, P = 0.04, and DL and DH LL, P < 0.0001), degree of browning (DL and DH GM, P = 0.002, and DL and DH LL, P < 0.0001), and discoloration (DL and DH GM, P = 0.01, and DH LL, P = 0.05) of the product was decreased. The DL GM steaks were juicier (P = 0.07), more acceptable (P = 0.05), and more satisfying (P = 0.01) than the control steaks. Seventy-seven percent of panelists would purchase the DL GM product (control, 61%, and DH, 60%). In conclusion, 55 d of rumen-protected HIS treatment positively impacts consumer perception and may optimize product quality and marketability in beef cattle.

Consumer sensory evaluation and chemical composition of beef gluteus medius and triceps brachii steaks from cattle finished on forage or concentrate diets.

The objective of this study was to assess the impact of cattle finishing diet and muscle type on meat quality. Consumer sensory response, proximate composition, Warner-Bratzler shear force (WBSF), fatty acid composition, and volatile compounds were assessed from the gluteus medius (GM) and triceps brachii (TB) muscles of cattle ( = 6 per diet) which were grain-finished (USUGrain) on conventional feedlot or 2 forage diets, a perennial legume, birdsfoot trefoil-finished (USUBFT; ), and grass-finished (USUGrass; ). Diet had an interacting effect with muscle for all sensory attributes ( ≤ 0.002), except aroma and flavor ( ≥ 0.078). In forage-finished beef, tenderness, fattiness, overall liking, and WBSF tenderness of GM was greater ( < 0.05) than TB, whereas for USUGrain, the tenderness, fattiness, overall liking, and WBSF tenderness of both muscles were similar ( > 0.05) but the juiciness of TB was more liked than USUGrain GM ( < 0.05). The juiciness of forage-finished beef did not differ ( > 0.05) between GM and TB. Lower ( < 0.05) intramuscular fat (IMF) percent was determined for USUGrass beef in comparison with USUGrain beef. The IMF percent of USUBFT beef was similar ( > 0.05) to both USUGrass and USUGrain beef. However, IMF percent was not impacted by muscle type ( = 0.092). The ratio of -6:-3 fatty acids was affected by muscle dependent on diet ( = 0.016). The ratio of -6:-3 fatty acids was affected by the interaction of muscle × diet ( = 0.016). Between forage diets (USUGrass and USUBFT), -6:-3 ratios were similar ( > 0.05) between GM and TB, whereas within USUGrain, the GM was greater ( < 0.05) than the TB. Cumulative MUFA was greater ( < 0.05) in USUGrain compared with both USUGrass and USUBFT, which were similar ( > 0.05). Strecker aldehydes, ketones, pyrazines, and methional were affected ( ≤ 0.036) by muscle and found to have a greater concentration in GM compared with TB. Overall, consumers determined that USUGrain GM and TB had similar ( > 0.05) quality ratings. However, within forage-finished beef, the GM was perceived more frequently ( < 0.05) to be of premium quality and the forage-finished TB was more frequently ( < 0.05) rated as having unsatisfactory quality. These findings were in agreement with ratings of tenderness and overall liking. Therefore, in the context of our consumer group grilled GM and TB steaks, grain-finished beef provided more uniform quality and eating experience compared with forage-finished beef.

Effect of vitamin D, zilpaterol hydrochloride supplementation, and postmortem aging on shear force measurements of three muscles in finishing beef steers.

Vitamin D (D3) supplementation may be used to increase tenderness in beef from cattle fed zilpaterol hydrochloride (ZH). The study was arranged as a 2 × 2 factorial with fixed effects of ZH (no ZH or ZH fed at 8.3 mg/kg DM for 20 d with a 3-d withdrawal) and D3 (no D3 or 500,000 IU D3·steer·d for 10 d prior to harvest). Cattle ( = 466) were harvested in 2 blocks on the basis of BW with subsequent collection of carcass data. Full loins and inside rounds ( = 144 of each subprimal) were collected for fabrication of 5 steaks from the longissimus lumborum (LL), gluteus medius (GM), and semimembranosus (SM), which were aged for 7, 14, 21, 28, or 35 d. Warner-Bratzler shear force (WBSF) was used to evaluate mechanical tenderness of LL, GM, and SM steaks at all aging periods. Slice shear force (SSF) analysis was conducted on only 14- and 21-d LL steaks. No interactions ( > 0.05) between ZH and D3 occurred throughout the entire study. Supplementing ZH resulted in increased HCW ( < 0.01), larger LM area ( < 0.01), and improved calculated yield grades ( < 0.01) with decreases in fat thickness ( = 0.02) and marbling scores ( = 0.05). Supplementation with D3 increased calculated yield grade ( < 0.01) and decreased ( = 0.01) rib eye area. Feeding ZH increased ( ≤ 0.05) WBSF of LL steaks at each postmortem age interval, whereas D3 had no effect ( > 0.05) on WBSF or SSF of LL steaks. Like for WBSF, ZH supplementation increased SSF values at 14 and 21 d postmortem ( < 0.01) compared with those for non-ZH steaks. There was an interaction between ZH and postmortem age ( < 0.01) for WBSF of LL steaks. At 7 d LL steaks from ZH steers sheared over 0.6 kg greater than non-ZH steaks; however, by 21 d this difference was reduced to an average of 0.2 kg. Differences in distribution between LL steaks below 3.0 kg from non-ZH and ZH-fed cattle were also notable ( ≤ 0.05) through 21 d of aging. At 35 d postmortem a high proportion of LL steaks (68.5%) from ZH-fed steers required less than 3.0 kg to shear. Supplementation with ZH and D3 had no impact ( > 0.05) on WBSF values of GM steaks. Feeding ZH did not alter WBSF of SM steaks, but at 28 d D3 increased ( = 0.04) WBSF values. Shear force in ZH steaks was not effectively reduced by feeding D3 for 10 d to steers prior to harvest. Aging, however, was an effective method of reducing initially greater shear force values in LL steaks and, to a lesser degree, GM steaks from ZH-fed cattle.

Aging implications on fresh muscle traits of Certified Angus Beef steaks.

Vacuum-packaged Certified Angus Beef (CAB) subprimals ( = 72) that included the longissimus thoracis (LT), longissimus lumborum (LL), gluteus medius (GM), and infraspinatus (IF) muscles were purchased from a major beef packing facility. Subprimals were allocated to 1 of 3 aging periods (14, 28, or 42 d) and aged at 2°C. After aging, 5 steaks were cut from each subprimal and assigned to pH, water-holding capacity, Warner-Bratzler shear force (WBSF), cooked color, cooking yield, cooking loss, and sensory panel analysis. Infraspinatus steaks were more tender ( < 0.05) than all other steaks, and subprimals aged 14 d had greater ( < 0.05) WBSF values than the other 2 aging periods, regardless of muscle. Water-holding capacity and cook yield were greater ( < 0.05) for LL and LT than IF and GM steaks, whereas purge loss was greater ( < 0.05) for IF and GM than LL and LT steaks. Throughout the aging periods, pH declined for all muscle groups, with IF steaks having the greatest ( < 0.05) pH values among all muscles. Among IF steaks, sensory evaluations of all attributes did not ( ≥ 0.26) differ across aging periods; yet among LT steaks, consumers rated those aged 14 d greater ( < 0.05) in overall impression than LT steaks aged 28 and 42 d. Among LT steaks, those aged 14 d received greater ( < 0.05) flavor ratings than LT steaks subjected to longer aging periods, and LT steaks aged 14 d received the greatest ( < 0.05) overall impression, with consumers giving greater ( < 0.05) overall impression scores to LT steaks aged 42 d over those aged 28 d. Aging period had no effect ( ≥ 0.017) on consumer ratings for flavor, tenderness, juiciness, or overall impression of LL steaks. Among GM steaks, consumers rated steaks aged 14 and 28 d more ( < 0.05) flavorful than those aged 42 d, and consumer ratings for overall impression were greater ( < 0.05) for GM steaks aged 28 d than for GM steaks aged 42 d; however, consumers failed ( = 0.035) to note differences in tenderness scores of GM steaks in response to aging period. Furthermore, consumers indicated a greater ( < 0.05) likelihood to purchase LT steaks aged 14 d over LT steaks aged 28 d, LL steaks aged 42 d over LL steaks aged 14 d, and GM steaks aged 14 and 28 d over GM steaks aged 42 d. These results indicate that consumers struggled to identify steak flavor attributes and suggest that the benefit of aging for premium beef products does not offer a tremendous sensory advantage to the consumer.

Effects of dietary potato by-product and rumen-protected histidine on growth, carcass characteristics and quality attributes of beef

We hypothesized that variable composition in finishing rations, more specifically; the proportion of potato-by-product (PBP) and rumen protected histidine (His) supplementation may influence growth and meat quality attributes. Two different diets were fed (1) finishing ration with corn and barley as grains (CB, n=20) and (2) substitution of 10% corn, DM basis, with PBP (PBP, n=20). Additionally, half of each dietary treatment received 50g/hd/d rumen protected His (HS, n=20) while the other half received no supplement (NS, n=20). Inclusion of 10% PBP or HS did not affect growth or carcass traits. Color stability was analyzed using Hunter color values as well as AMSA visual appraisal in both longissimus thoracis (LT) and gluteus medius (GM) muscles. The LT, but not the GM, of CB steers was more color stable over a 9d simulated retail display compared to those fed a PB diet. Steers receiving HS produced significantly (P<0.05) more color stable LT and GM steaks.

The effects of freezing and thawing rates on tenderness, sensory quality, and retail display of beef subprimals1,2

The objective of this study was to evaluate processing methods for frozen beef subprimals; the effects of freezing and thawing rates on tenderness, sensory properties, and retail display were evaluated. There were 6 treatments: fresh, never frozen 14 d wet aged (14D); fresh, never frozen 21 d wet aged (21D); blast frozen-fast thawed (BF); blast frozen-slow thawed (BS); conventionally frozen-fast thawed (CF); and conventionally frozen-slow thawed (CS). All frozen beef subprimals were aged for 14 d before freezing. Three beef subprimal cuts, rib eye roll (n=90), strip loin (n=90), and top sirloin butt (n=90), were used with 3 replications of 5 samples per treatment per week (total of 9 wk, n=270). Blast freezing occurred by placing spacers between the boxes of meat on pallets at -28°C with high air velocity for 3 to 5 d. Conventional freezing occurred with boxes of meat stacked on pallets and placed in a -28°C freezer with minimal air movement for at least 10 d. Fast thawing of subprimals (to an internal temperature of -1°C to 1°C) occurred by immersion in a circulating water bath (<12°C) for 21 h, and slow thawing of subprimals occurred over a 2-wk period by placing individual subprimals on tables at 0°C. Steaks (2.5 cm thick) were cut from the longissimus thoracis (LT), longissimus lumborum (LL), and gluteus medius (GM) for Warner-Bratzler shear force (WBS), trained sensory evaluation, and retail display. For LL and GM beef steaks, frozen treatments were equal or lower in WBS values to 14D and 21D beef steaks. No differences were detected in WBS among the treatments applied to GM beef steaks (P=0.08). There were no differences in sensory tenderness among the LL, LT, and GM (P>0.05). All LL and LT beef steaks had approximately 4 d to 40% discoloration, and all GM steaks had over 3 d to 40% discoloration. Steaks from the LL and LT began to discolor at about 3 d, and the GM began to discolor after 1 d. For all beef subprimals, purge loss during storage and thawing was significantly greater for the slow-thawed subprimals (P<0.01), and all fast-thawed subprimals were equal or superior to 14D and 21D (P<0.01) in storage and thawing purge. During retail display, the greatest purge loss occurred in fast-thawed treatments (P<0.01). Overall, freezing rate did not affect purge loss, and neither freezing nor thawing rates had significant meaningful effects on WBS, and sensory properties were comparable with fresh, never-frozen subprimals.

Effects of supplementing feedlot steers and heifers with zilpaterol hydrochloride on Warner–Bratzler shear force interrelationships of steer and heifer longissimus lumborum and heifer triceps brachii and gluteus medius muscles aged for 7, 14 and 21d

Longissimus lumborum (LL) muscles from 117 steers plus LL, gluteus medius (GM), and triceps brachii (TB) muscles from 132 heifers were evaluated for effects of feeding duration of zilpaterol hydrochloride (Zilmax(R); ZH; 7.56g/907kg on a dry matter basis) and aging time on tenderness. Both genders were blocked by initial weight into six blocks of four pens. Pens were assigned to treatments of control (C), or 20, 30 or 40days on ZH, with a 3day withdrawal. Steaks from each subprimal were vacuum aged individually for 7, 14 or 21days, frozen, thawed, and cooked to 71 degrees C for Warner-Bratzler shear force (WBSF). All muscles from steers and heifers from ZH30 and ZH40 treatments had higher (P<0.05) WBSF than those of C. The WBSF of steer LL and heifer TB from the ZH20 treatment was higher (P<0.05) than C. There was a treatment by aging interaction (P>0.05) for WBSF of GM steaks from heifers. Percentage of intramuscular fat had little effect on tenderness. Percentages of steer LL and heifer TB steaks with WBSF values below thresholds of either 5.0 or 4.6kg from the ZH20 treatment were quite high, whereas percentages of heifer LL and GM muscles below 5.0kg (67%) and 4.6kg (57%) were low. Feeding ZH20days generally increased WBSF values, but mean WBSF values for steer LL and heifer TB were below 4.6kg. Feeding ZH 20days resulted in>40% of GM steaks with WBSF values above 4.6kg.

Effects of zilpaterol hydrochloride feeding duration and postmortem aging on Warner-Bratzler shear force of three muscles from beef steers and heifers

To determine the effects of zilpaterol hydrochloride (ZH; 6.8 g/t on 90% DM basis) feeding duration (0, 20, 30, and 40 d) on Warner-Bratzler shear force (WBSF) of longissimus lumborum (LL), triceps brachii (TB), and gluteus medius (GM) muscles, beef from feeding trials was collected and shipped to participating universities. Animals were slaughtered at commercial processing facilities across the United States. Strip loin, shoulder clod, and top sirloin butt subprimals (IMPS 180, 114, and 184, respectively) were obtained from a portion of USDA Choice and Select grade carcasses for WBSF using standardized procedures and equipment. Feeding ZH increased (P < 0.001) LL WBSF values of USDA Choice and Select steaks. A significant linear contrast existed for both quality grades, indicating increased WBSF values were associated with longer feeding durations. Increased postmortem aging decreased LL WBSF of control and treated steaks. Postmortem aging from 7 to 21 d decreased LL WBSF values by 17.6 and 16.4% for USDA Choice and Select steaks, respectively. The percentage of LL steaks from ZH-supplemented cattle with a WBSF value <4.5 kg was significantly less than control steaks for both quality grades. Postmortem aging from 7 to 21 d postmortem increased (P < 0.001) the percentage of LL Choice and Select steaks with WBSF <4.5 kg for all ZH feeding durations. Feeding ZH for 20, 30, or 40 d increased (P < 0.01) WBSF of USDA Choice TB and GM steaks compared with 0-d controls. Feeding ZH for 0, 20, and 40 d had a similar effect on WBSF of USDA Select GM steaks, and produced lesser values than steaks from cattle fed ZH for 30 d. Feeding ZH for 20, 30, and 40 d had no effect on WBSF values of USDA Select TB steaks. However, the 20-, 30-, and 40-d duration produced WBSF values greater (P < 0.05) than control (0 d) TB steaks. Postmortem aging decreased (P < 0.05) WBSF of USDA Choice and Select TB and GM steaks, but the percentage improvement in WBSF attributed to aging was less than observed for LL steaks. The results of this study indicate feeding ZH increased (P < 0.001) WBSF of LL, TB, and GM. The ZH feeding also decreased (P < 0.01) the percentage of steaks with WBSF <4.5 kg regardless of US quality grade, whereas postmortem aging increased (P < 0.01) the percentage of US Choice and Select steaks with WBSF <4.5 kg. Finally, postmortem aging reduced (P < 0.05) WBSF of steaks from ZH-supplemented beef cattle.

The effect of zilpaterol hydrochloride on meat quality of calf-fed Holstein steers

The objective of these studies was to evaluate the effects of zilpaterol hydrochloride (ZH), fed for 0, 20, or 30 d, on meat quality attributes of calf-fed Holstein steers. Steers were slaughtered at a commercial facility, and carcasses were selected by HCW to represent the pen mean. Further carcass selection was based on quality grade (Choice and Select) and yield grade. Proximate composition, measures of water holding capacity, and tenderness using Warner-Bratzler shear force after 7, 14, or 21 d postmortem were evaluated on the shoulder clod (triceps brachii), top butt (gluteus medius), and strip loin (longissimus lumborum). Percentage of purge for the 3 subprimals was not different (P > 0.05) among ZH treatments. Steers fed ZH for 20 d or 30 d had decreased (P < 0.05) percentages of fat in the triceps brachii, compared with 0-d ZH. Percentage of fat was less (P < 0.05) in the gluteus medius and longissimus lumborum when steers were fed ZH for 30 d compared with those steers fed ZH for 0 d. Percentage of fat was greater in Choice triceps brachii (P < 0.05) and longissimus lumborum (P < 0.10) compared with Select. Thaw loss was not different (P > 0.05) for any muscle due to ZH treatment. Only longissimus had a greater (P < 0.05) cooking loss with ZH treatment. Cooking loss was not different (P > 0.05) for the gluteus medius or longissimus lumborum due to quality grade or aging day. At each aging day, the 20- and 30-d ZH longissimus lumborum had greater (P < 0.05) shear force values than 0 d; however, 20- and 30-d ZH had a greater absolute change in shear force from 7 to 21 d than that of 0 d ZH. Triceps brachii steaks were less tender (P < 0.05) after ZH treatment, but gluteus medius steaks were not different (P > 0.05). There was no difference (P > 0.05) in shear force due to quality grade. Results illustrate the use of ZH in calf-fed Holstein steers will have minimal effects on purge, thaw, or cooking loss. Percentage of intramuscular fat will decrease, especially when fed for longer durations. Steaks from ZH treated steers were tougher than steaks from control animals at all aging times, but ZH steaks became more tender with postmortem aging.

Effect of blade tenderization, aging time, and aging temperature on tenderness of beef longissimus lumborum and gluteus medius1,2

Purveyors are concerned about the potential food safety risk of nonintact meat products and are seeking strategies to ensure adequate meat tenderness without blade tenderization. This study was conducted to determine the effects of blade tenderization and time and temperature of aging on beef longissimus lumborum (LL) and gluteus medius (GM) tenderness. Beef strip loins (n = 300) and top sirloin butts (n = 300) were assigned to storage at -0.5 or 3.3 degrees C for 12, 26, or 40 d. Cuts were blade tenderized (BT) or not blade tenderized (NBT) before steak cutting. One 2.54-cm steak from each subprimal was used for slice shear force determination and Western blotting of desmin. Desmin degradation was less (P < 0.05) in LL stored at -0.5 degrees C than LL stored at 3.3 degrees C (57 and 65%, respectively). Aging from 12 to 26 d increased (P < 0.05) proteolysis (50 to 65%) in LL. Regardless of aging time, BT reduced (P < 0.05) LL slice shear force values. Aging time did not affect (P > 0.05) slice shear force values of BT LL steaks (10.4, 9.9, and 9.4 kg for 12, 26, and 40 d aging, respectively), but reduced (P < 0.05) NBT steak slice shear force values (15.1, 13.8, and 12.3 kg for 12, 26, and 40 d aging, respectively). Greater temperature did not affect (P > 0.05) slice shear force values of BT LL steaks (10.2 and 9.6 kg for steaks aged at -0.5 and 3.3 degrees C, respectively), but improved (P < 0.05) slice shear force of NBT LL steaks (15.1 and 12.4, respectively). Aging at 3.3 degrees C increased (P < 0.05) proteolysis in GM steaks (43 and 54% for -0.5 and 3.3 degrees C, respectively). Longer aging times increased (P < 0.05) proteolysis (40, 46, and 60% for 12, 26, and 40 d aging, respectively) in GM steaks. Blade-tenderized GM steaks had dramatically less (P < 0.05) slice shear force values than NBT steaks (13.7 and 19.9 kg, respectively). Raising aging temperature from -0.5 to 3.3 degrees C reduced (17.6 vs. 16.0 kg; P < 0.05) and increasing aging time from 12 d to 40 d improved (17.9 vs. 15.2 kg; P < 0.05) slice shear force values of GM steaks. Blade tenderization and increased aging time and temperature all improved tenderness of beef LL and GM steaks, though blade tenderization provided greater improvements than increased aging time and temperature. Longer aging could potentially be used to replace blade tenderization for LL steaks, but not in GM steaks.

Comparison of palatability characteristics of beef gluteus medius and triceps brachii muscles1,2

The objective of this experiment was to evaluate triceps brachii steaks as a substitute for gluteus medius steaks in foodservice and retail applications, including the effect of aging time and USDA quality grade on the palatability of both muscles. Top sirloin butts (n = 600) and shoulder clod arm roasts (n = 600) representing US Choice and US Select quality grades were selected at 48 h postmortem and aged for 7, 14, 21, 28, 35, or 42 d. Steaks were evaluated using a trained sensory panel, slice shear force, sarcomere length, and Western blotting of desmin measurements. Sarcomere length was measured only on steaks at 14 and 42 d. Triceps brachii and gluteus medius steaks were similar in tenderness rating at 7 and 14 d, but triceps brachii steaks aged longer were more tender (P < 0.05) than were gluteus medius steaks. Triceps brachii steaks reached ultimate tenderness values by 21 d. Gluteus medius steak tenderness ratings improved through 35 d, and at 42 d were similar to those given to triceps brachii steaks at 21 d. Sarcomere lengths were longer (P < 0.05) in triceps brachii than in gluteus medius (2.09 and 1.58 mum, respectively). Significant increases in desmin degradation were detected through 42 d in both muscles (30.9, 46.3, 50.6, 51.0, 57.6, and 64.1% at d 7, 14, 21, 28, 35, and 42 for gluteus medius and 28.9, 40.8, 49.3, 59.2, 61.8, and 71.9% at d 7, 14, 21, 28, 35, and 42 for triceps brachii). At 14 d, gluteus medius had more (P < 0.05) desmin degraded than triceps brachii, but by 28 d, desmin degradation was greater (P < 0.05) in triceps brachii. Quality grade had minimal effects on palatability traits. Desmin degradation contributed to gluteus medius tenderness variation (r = 0.36) across all aging times, but not at individual aging times. Sarcomere length contributed to variation in slice shear force values of gluteus medius at 14 and 42 d (r = -0.59 and -0.48, respectively). Sarcomere length contributed to triceps brachii tenderness variation at 14 d, but not 42 d (r = 0.44 and -0.12, respectively). Desmin degradation was strongly correlated (r = 0.55) to triceps brachii tenderness ratings pooled across aging times but not at individual aging times. These data indicate that triceps brachii steaks could provide the same or improved palatability as gluteus medius steaks at the same or slightly shorter aging times.