Impact of myoglobin oxygenation state prior to frozen storage on color stability of thawed beef steaks through retail display.

Consumers consider beef color to be an indicator of freshness and therefore it is a major factor when purchasing beef. The ideal conditions for maintaining color throughout retail display following frozen storage have yet to be well established. Therefore, the objective of this study was to determine the effects of myoglobin oxygenation levels (especially high oxygenation) during freezing on color stability of thawed steaks during retail display (RD) and to determine the impact that frozen storage duration, aging, and packaging films have on meat color after thawing under RD conditions. USDA Choice strip loins (n = 36) were aged for 4 or 20 d. Steaks were randomly assigned to a myoglobin oxygenation level [deoxymyoglobin (DeOxy; packaged within 3 min), oxygenation (Oxy; oxygenated in air for 30 min), or high oxygenation (HiOxy; packaged for 24 h in 80% O2)]. Steaks were then vacuum packaged in oxygen permeable or impermeable film and immediately frozen (-10 °C). Following either 0, 2, 4, or 6 months of frozen storage at -5 °C, steaks were removed from the packaging and immediately placed under simulated RD conditions for 7 d. During RD, instrumental color and subjective color were measured every day after the initial 24 h thaw period. Steaks were analyzed for instrumental color (L*, a*, b*), a*:b* ratio, percentage oxymyoglobin, metmyoglobin, and deoxymyoglobin, delta E, redness ratio, subjective discoloration, and lipid oxidation. For all days of RD, steaks that were frozen for 0 months had higher a* values (greater redness) than steaks frozen for 6 months which typically had the lowest a* values (P < .0001). HiOxy steaks frozen for 6 months had the lowest amounts of percentage oxymyoglobin than all other frozen storage periods and myoglobin oxygenation levels on days 4-7 of RD (P < .05). The HiOxy steaks frozen for 4 and 6 months had higher percentage metmyoglobin than DeOxy and Oxy, regardless of packaging (P < .05). Delta E, discoloration, and lipid oxidation were greatest for HiOxy steaks compared to Oxy and DeOxy (P < .05). Extended storage brought about detrimental color effects for all differing levels of myoglobin oxygenation. The HiOxy steaks through the first few days of RD and frozen for under 6 months provided had bright cherry red color, similar to that of DeOxy and Oxy. However, with extended frozen storage and RD, HiOxy steaks had worse color characteristics (more discoloration) than the other myoglobin oxygenation levels.

Effects of different antioxidants on quality of beef patties from steers fed low-moisture distillers grains.

This research evaluated the effects of different antioxidants on overall quality of beef patties from steers fed distillers grains. Crossbred steers (n = 24) were fed corn, 40% Dry distillers grains plus solubles, or 40% modified distillers grains plus solubles - Dry Matter basis). Patties were made from ground chuck of individual animals and 4 antioxidant treatments were evaluated (CONTROL - no antioxidant, 0.3% ROSEMARY, 0.25% ACEROLA, and 0.6% CITRUS). Diets minimally affected quality attributes. Patties treated with ROSEMARY were shown significant lighter in color than other treatments on day 6. Patties treated with CITRUS were the reddest on days 5 and 6 of display. ACEROLA and CITRUS provided better lipid stability during display when compared to CONTROL and ROSEMARY. Treatment CITRUS reduced APC growth by 2 log when compared to all other treatments (P < 0.01). Although patties treated with CITRUS had higher off-flavor intensity, no effect was observed for overall desirability. Patties treated with 0.6% of CITRUS provided optimal overall quality.

Effects of finishing diets containing wet distillers grains plus solubles on beef quality attributes and fatty acid profile.

The objective of this study was to evaluate the effects of feeding wet distillers grains plus solubles (WDGS) on quality attributes of three beef muscles (longissimus lumborum, psoas major, and infraspinatus). Ninety-six, yearlings crossbred steers were randomly assigned to one of three dietary treatments (Corn, 15%, or 30% WDGS - DM basis) and fed for 133 d. No significant differences were observed in marbling score (P=0.89), marbling texture (P=0.70), and marbling distribution (P=0.36). Greater concentrations of PUFA and lower levels of 18:1(n-7) were observed in beef from steers fed 30% WDGS when compared to other treatments. Lipid oxidation was also greater in beef from steers fed 30% WDGS (P≤0.05). No significant differences were observed in sensorial attributes and Warner-Bratzler shear force (WBSF) for all muscles (P>0.05). Feeding WDGS increased PUFA and lipid oxidation, which may lead to shorter shelf life.

Evaluation of palatability and muscle composition of novel value-added beef cuts.

The aim of this study was to evaluate the muscle profile of novel added-value beef cuts including the caudal tip of the M. infraspinatus (Bonanza Cut; TIP) and M. subscapularis (SUB) and two traditional sirloin steak cuts, M. gluteus medius (top sirloin; GLM) and M. rectus femoris (sirloin tip; REC). Samples were subjected to Warner-Braztler Shear Force (WBSF), sensory, cooking loss, and proximate analysis. The muscle TIP had superior values of subjective tenderness, juiciness, and slight off-flavor intensity when compared to all other muscles. The TIP and SUB were similar in WBSF. Cooking loss and moisture values of raw samples were lowest for TIP. Results suggest that TIP can provide enhanced eating experience for consumers and improved marketability for the meat industry.

Impact of feeding de-oiled wet distillers grains plus solubles on beef shelf life.

Research was conducted to determine the effect of feeding de-oiled wet distillers grains plus solubles (WDGS) on beef fatty acid profile, retail shelf life and development of oxidation products during retail display (RD). A total of 336 crossbred yearling steers (initial BW = 351.08 ± 19.05 kg) were fed 1 of 7 dietary treatments: an all corn control (1:1 blend of dry rolled and high moisture corn), 35%, 50%, or 65% inclusion of WDGS, either full-fat or de-oiled. Within each treatment 15 Choice carcasses were randomly selected ( = 105), strip loins were obtained, aged 7 and 21 d, and representative steaks from each strip loin were placed in RD conditions for 7 d. Fatty acid profiles were determined (mg/100 g tissue basis) and differences ( ≤ 0.05) were found in the C16:1, C18:1T, C18:2 and total polyunsaturated fatty acids (PUFA) among dietary treatments. Palmitoleic acid (C16:1) was predominant ( < 0.0001) in the corn control group, intermediate in the 35% de-oiled WDGS group, but no differences ( > 0.05) were observed between all other diets. Elaidic acid (C18:1T) was greater ( = 0.01) in the 65% full-fat WDGS group, least for the corn control group, and intermediate for all other diets. Linoleic acid (C18:2) was greater ( = 0.0001) in all 3 full-fat WDGS groups and 65% de-oiled WDGS group (290.98 mg/100 g, on average), intermediate in the 50% and 35% de-oiled WDGS groups (231.08 and 227.16 mg/100 g, respectively) and least for the corn control group (177.70 mg/100 g). The PUFA content was greater ( < 0.01) in all 3 full-fat WDGS groups and 65% de-oiled WDGS group (337.13 mg/100 g, on average), intermediate in the 50% and 35% de-oiled WGDS groups (274.77 and 273.84 mg/100 g, respectively) and least for the corn control group (223.98 mg/100 g). Dietary treatment did not alter discoloration ( = 0.30) or lipid oxidation ( = 0.36). Shear force decreased with age and RD ( < 0.0001) but dietary treatment had no effect on shear force ( = 0.93). In general, feeding 35% and 50% de-oiled WDGS had intermediate PUFA content relative to a corn control or full-fat WDGS diet. Feeding de-oiled WDGS did not seem to increase beef shelf life and does not negatively alter beef quality parameters in relation to full-fat WDGS.

Beef palatability and its relationship with protein degradation and muscle fibre type profile in longissimus thoracis in Alentejana breed from divergent growth pathways.

The traditional beef production in the South of Portugal is based on a discontinuous growth (DG) system that requires lower external inputs and could enhance meat quality and financial returns to cattle producers. This system allows farmers to take advantage of the bull's compensatory growth when the pasture is abundant and finishes the cattle on concentrates for 2 to 3 months before slaughter. The fast gain rate before slaughter could be a valuable strategy to improve tenderness and to reduce its inconsistency in beef production. Therefore, the aim of this study was to evaluate the effects of production system (continuous growth (CG) v. DG) on longissimus thoracis muscle properties from Alentejana bulls. In total, 40 Alentejana male calves were allocated to two distinct feeding regimes: in the CG system, animals were fed concentrate plus hay and slaughtered at 18 months of age, whereas in the DG system, animals were fed on hay until 15 months of age and then fed the same diet provided to the CG group until 24 months of age. The DG system had a positive impact on meat tenderness (P<0.001) and global acceptability (P<0.001). DG bulls had greater fibre cross-sectional area (CSA) of glycolytic fibres (P<0.05) and relative area of the muscle (RA) occupied by type IIX fibres (P<0.01) and greater levels of α-actinin (P<0.05) and myosin light chain 2 (P<0.01) proteins, and pH24h (P<0.01) than CG bulls. The latter had greater CSA of type I (P<0.05) and type IIA (P<0.01) and greater RA of type IIA (P<0.05) and oxidative (P<0.05) than CG bulls. The compensatory growth production system had a positive impact on meat tenderness and global acceptability, overcoming the negative effects of slaughter of the bulls at a later age. The DG beef system could be a worthwhile strategy of beef production in Mediterranean areas due to the low-quality pasture in summer.

Repercussions of growth path on carcass characteristics, meat colour and shear force in Alentejana bulls.

The aim of this study was to evaluate the carcass and meat characteristics of eight muscles from bulls with distinct growth paths. A total of 40 Alentejana male calves were allocated to two distinct feeding regimes. In the continuous growth (CG) system, the animals were fed concentrates plus hay and were slaughtered at 18 months of age. On the other hand, in the discontinuous growth (DG) system, the animals were fed hay until 15 months of age; the cattle were then fed the same diet provided to the CG group from 15 to 24 months of age. The DG reduced hot carcass weight, fatness and dressing %, but the proportions of fat, bone and muscle tissues in the leg were not affected. In contrast, there was a positive impact of compensatory growth on supraspinatus, triceps brachii, semitendinosus, biceps femoris muscle tenderness, overcoming the negative effects of age at slaughter. The reasons for such improvement in meat tenderness were not related to intra-muscular fat content or myofibrillar protein degradation values. An association between tenderness and muscle collagen properties was not established. The results indicate that the compensatory growth has a muscle-dependent effect.

Genome wide association study of cholesterol and poly- and monounsaturated fatty acids, protein, and mineral content of beef from crossbred cattle.

The objectives were to determine the variation explained by the BovineSNP50v2 BeadChip for cholesterol (CH), polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), protein, and minerals in beef cattle, and to identify chromosomal regions that harbor major allelic variants underlying the variation of these traits. Crossbred steers and heifers (n=236) segregating at the inactive myostatin allele on BTA2 were harvested and steaks were sampled from the M. semitendinosus and the M. longissimus thoracis et lumborum for nutrient analysis. A Bayes C algorithm was employed in genome-wide association analysis. The resulting posterior heritability (SD) estimates ranged from 0.43 (0.10) to 0.71 (0.08) for lipid traits and 0.05 (0.08) to 0.75 (0.06) for mineral traits. Across cuts, correlations between genomic estimated breeding values (GEBV) were similar for CH, MUFA and PUFA. The top 0.5% 1-Mb windows for all traits explained up to 9.93% of the SNP variance. Slight differences did exist between cuts and between different measurement scales of fatty acids.

The effects of freezing and thawing rates on tenderness, sensory quality, and retail display of beef subprimals.

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 feeding modified distillers grains plus solubles on marbling attributes, proximate composition, and fatty acid profile of beef.

Wet distillers grains contain approximately 65% moisture. A partially dried product [modified distillers grains plus solubles (MDGS)] contains about 50% moisture. However, both have similar nutrient composition on a dry matter basis. The objective of this study was to investigate the effects of finishing diets varying in concentration of MDGS on marbling attributes, proximate composition, and fatty acid profile of beef. Yearling steers (n = 268) were randomly allotted to 36 pens, which were assigned randomly to 0, 10, 20, 30, 40 and 50% MDGS (DM basis) and fed for 176 d before harvest. The 48-h postmortem marbling score, marbling texture, and marbling distribution were assessed by a USDA grader and 1 ribeye slice (longissimus thoracis) 7 mm thick was collected from each carcass for proximate and fatty acid analyses. Treatments did not significantly alter marbling score or marbling distribution (P ≥ 0.05). United States Department of Agriculture Choice slices had coarser marbling texture when compared with USDA Select. Although dietary treatment affected marbling texture, no consistent pattern was evident. Diets did not influence fat content, moisture, or ash of the ribeye (P ≥ 0.05). For treatments 0, 10, 30, 40 and 50%, there were positive linear relationships between marbling score and fat percentage in the ribeye (P ≤ 0.05), and all slopes were similar (P = 0.45). Feeding MDGS linearly increased stearic, linoelaidic, linoleic, linolenic, PUFA, and n-6 fatty acids. As dietary MDGS increased, linear decreases were observed in all n-7 fatty acids and cubic relationships were detected for the 18:1 trans isomers [trans-6-8-octadecenoic acid (6-8t), elaidic acid (9t), trans-10-octadecenoic acid (10t), and trans vaccenic acid (11t)]. No effects were observed for saturated fatty acids containing 6 to 14 carbons. Feeding MDGS resulted in increased PUFA, trans, and n-6 fatty acids, minimal effects on marbling texture, and no effects on the relationship of marbling to intramuscular fat content relationship.

Beef quality of calf-fed steers finished on varying levels of corn-based wet distillers grains plus solubles.

Calf-fed crossbred steers (n = 94) were randomly allocated to 3 dietary treatments (0%, 15%, or 30% wet distillers grains plus solubles, WDGS; DM basis) and fed for 167 d to determine the effects on quality attributes of beef. At 48 h postmortem, marbling score, marbling texture, and marbling distribution were assessed by a USDA grader. After grading, one rib eye slice (longissimus thoracis) ¼7 mm thick was excised from each carcass, trimmed of subcutaneous fat, and analyzed for fatty acid profile and lipid content. At 7 d postmortem, 48 top blades (infraspinatus), strip loins (longissimus lumborum), and tenderloins (psoas major) (16 per treatment) were removed from shoulder clods and short loins and 2 steaks were obtained to measure mineral content, fatty acid profile (except strip loins), trained sensory analysis, objective color, and lipid oxidation. Finishing diet did not influence the content of total lipid (P = 0.19) or marbling, marbling texture, or marbling distribution (P = 0.46, 0.84, 0.40, respectively). Feeding WDGS created a linear increase (P < 0.01) of PUFA in all three muscles (longissimus thoracis showed 4.90%, 5.91%, and 6.23% PUFA for 0%, 15%, and 30% WDGS, respectively). Similar responses were observed for 18:2(n-6) and total n-6 fatty acids. Conversely, lower proportions of 18:1(n-7) fatty acid were observed in beef from animals fed 30% WDGS (P < 0.01). Total trans fatty acids increased linearly in strip loin and top blade steaks (P < 0.01), whereas proportions of 16:0 and 14:1(n-5) fatty acids decreased in all muscles (P < 0.01) as WDGS increased. Diet did not affect mineral content of top blades or strip loins. For tenderloin steaks, S concentration was lower when 30% of WDGS was fed (P = 0.05). No effects on sensory attributes and Warner-Bratzler shear force were observed (P > 0.50), except a minimal effect on strip loin juiciness (5.32, 4.86, and 5.52 for 0%, 15%, and 30% WDGS, respectively; P = 0.02). Top blade and tenderloin steaks from cattle fed 30% WDGS were significantly less red (lower a* values) on d 3 of simulated retail display (P < 0.04). Inclusion of 30% WDGS in the diet resulted in higher levels of oxidation after 7 d of retail display for top blade and strip loin steaks (P < 0.01). Feeding WDGS to calf-fed steers altered fatty acid profile, increased oxidation, and decreased color stability during retail display.

Evaluation of performance, carcass characteristics, and sensory attributes of beef from finishing steers fed field peas.

Whole field peas were fed at 0, 10, 20, and 30% of DM to 139 yearling steers (British cross; 409 ± 31 kg of initial BW) for a 119-d finishing period. Carcass data and Choice grade strip loins (n = 98) were collected from a commercial abattoir in Lexington, Nebraska. Consumer sensory and Warner-Bratzler shear force analyses were performed on 2.5-cm strip steaks. No differences (P ≥ 0.17) were observed in final BW, ADG, DMI, and G:F of steers. Likewise, no differences (P ≥ 0.23) were observed for HCW, LM area, fat thickness at the 12th rib, yield grade, and marbling scores. However, KPH responded quadratically to increasing dietary amount of field peas (P = 0.02). Regarding the sensorial analysis, feeding peas linearly increased subjective tenderness (P < 0.01) and led to a quadratic response of overall like ratings (P = 0.01) and flavor like ratings (P = 0.12). Feeding peas did not alter (P ≥ 0.64) juiciness, but decreased shear force values linearly when quantities were increased (P = 0.02). These data suggest that feeding peas does not affect steer performance or carcass characteristics differently from dry-rolled corn, but does improve objective and subjective tenderness, overall desirability, and flavor of beef. Field peas could be fed to cattle and give positive attributes to the quality of the meat up to 30% inclusion in the diet.

Mapping of intramuscular tenderness and muscle fiber orientation of muscles in the beef round.

Intramuscular tenderness variation and muscle fiber orientation of beef M. adductor femoris (AF), M. biceps femoris (BF), M. gracilis (GL), M. pectineus (PT), M. sartorius (SR), M. semimembranosus (SM), M. semitendinosus (SO), M. vastus intermedius (VI), M. vastus medialis (VM), and M. vastus lateralis (VL) were investigated. The USDA Choice boxed beef subprimals were purchased and aged for 14 d from boxed date. The AF, BF, GL, PT, SR, SM, SO, VI, VM, and VL (n = 10 each) were fabricated from subprimals. Crust-frozen AF, BF, SO, SM, and VL were cut into 2.54-cm steaks perpendicular to the long axis and grilled (71 degrees C). The PT, SR, VI, and VM were grilled (71 degrees C) as whole muscles, whereas the GL was grilled after cutting into anterior and posterior regions. Grilled muscles were cut into equal size sections perpendicular to long axis of muscles. Location-specific cores were prepared from each steak/section, and Warner-Bratzler shear force (WBSF) was measured. The muscle fiber orientations of BF, PT, and VI were bipennate, SR and SO were fusiform, and AD, SM, VL, GL, and VM were unipennate. The overall mean WBSF values for BF, SO, AF, SM, PT, SR, GL, VI, VM, and VL were 5.62, 4.86, 4.18, 4.90, 3.76, 4.44, 4.75, 4.78, 4.24, and 6.53 kg, respectively. Based on WBSF values, PT was tender, BF and VL were tough, and VM, VI, SM, GL SR, AF, and SO were intermediate. The first 2 proximal steaks of long head BF were more tender than the rest (P < 0.05). In the SO, the tenderness decreased from the middle of the muscle to both ends (P < 0.05). The anterior sides of the long head BF and SO were tougher than their posterior sides (P < 0.05).The first 4 steaks of the SM were more tender than the rest of the muscle (P < 0.05). There was a significant tenderness increment from the middle of the AF and SR to both ends of each muscle (P < 0.05). The medial side of the VI was more tender than its lateral side (P < 0.05). The VM had its smallest shear force value at the most distal end compared with the rest (P < 0.05). Dry or moist heat oven roasting, as compared with grilling, significantly tenderized SO (P = 0.002) and VL (P < 0.0001) muscles. There were no significant WBSF value differences along the PT and between anterior and posterior regions of the GL. Based on WBSF ratings, PT, SR, VM, GL, and VI could be merchandized as single muscle steaks or medallions and the first 2 to 4 steaks of long head BF, SM, and AF could be marketed as premium-quality steaks. This detailed information on intramuscular tenderness and muscle fiber orientation variations of the round muscles could be used in a value added strategy for the beef round.

Effect of cooking method, distiller's grains, and vitamin E supplementation on the vitamin content of value cuts from beef steers fed wet distiller's grains and solubles and supplemental vitamin E.

Vitamin E, thiamin, riboflavin, niacin, vitamin B(6), and vitamin B(12) concentrations of flat iron steaks and petite tenders from steers fed finishing rations containing 0% and 40% corn wet distiller's grains and solubles (WDGS) with and without supplemental vitamin E were determined. Feeding treatment groups were: 0% WDGS with basal vitamin E, 0% WDGS with supplemental vitamin E (500 IU daily), 40% WDGS with basal vitamin E, and 40% WDGS and supplemental vitamin E. Cattle can be fed 40% WDGS diets more economically than corn diets. The incorporation of 40% WDGS, with and without vitamin E, was hypothesized to have little effect on the vitamin concentrations of these value meat cuts. Flat iron steaks and petite tenders were broiled and/or grilled to 70 degrees C internal temperature. Mean cooking yields ranged from 68.7% to 78.2%. The majority of the vitamin concentrations of broiled and of grilled meat were significantly different (P < 0.05) from that of raw meat. Vitamin E concentrations of raw and cooked meat from steers that received supplemental vitamin E were significantly higher (P < 0.05) than those fed basal vitamin E. Significant differences in thiamin, riboflavin, vitamin B(6), and vitamin B(12) concentrations in raw flat iron steaks and in vitamin B(6) in raw petite tenders were observed by WDGS. Thiamin, vitamin B(6), and vitamin B(12) concentrations of broiled flat iron steaks were significantly different (P < 0.05) than grilled. A few differences in vitamin concentrations of the flat iron steaks and petite tenders were observed by WDGS, vitamin E supplementation, and cooking treatments, but most of the vitamin concentrations were statistically similar.

Application of exogenous enzymes to beef muscle of high and low-connective tissue.

Exogenous enzymes tenderize meat through proteolysis. Triceps brachii and Supraspinatus were randomly assigned to the seven enzyme treatments, papain, ficin, bromelain, homogenized fresh ginger, Bacillus subtilis protease, and two Aspergillus oryzae proteases or control to determine the extent of tenderization (Warner-Bratzler shear and sensory evaluation) and mode of action (myofibrillar or collagen degradation). Sensory evaluation showed improvement (P<0.0009) for tenderness and connective tissue component and all except ginger had a lower shear force than the control (P<0.003). Ginger produced more off-flavor than all other treatments (P<0.0001). Only papain increased soluble collagen (P<0.0001). Control samples were only significantly less than ficin for water soluble (P=0.0002) and A. oryzae concentrate for salt soluble proteins (P=0.0148). All enzyme treatments can increase tenderness via myofibrillar and collagenous protein degradation with no difference among high and low-connective tissue muscles.

Efficacy of performing Warner-Bratzler and slice shear force on the same beef steak following rapid cooking.

The ability to perform Warner-Bratzler and slice shear force on the same beef top loin steak was investigated. Three, 2.54-cm steaks from top loins (n=99) were allotted to either Warner-Bratzler only (WBS), slice shear force only (SSF), or Warner-Bratzler and slice shear force (WBS/SSF). Steaks were thawed at 2 degrees C for 48h prior to cooking. Steaks were cooked to 71 degrees C using a conveyor convection oven and allowed to cool at room temperature for a minimum of 4h. Steaks allotted to WBS used six 1.27-cm cores and steaks allotted for WBS/SSF used four cores. Steaks allotted to SSF and WBS/SSF used one, 1 cm x 5 cm slice. Correlations among WBS and SSF for all steaks ranged from 0.49 to 0.69 (P<0.0001). When correlations were generated for steak location within the top loin, the relationships among WBS and SSF performed in the same steak ranged from 0.53 to 0.70 (P<0.05). These results indicate that it may be feasible to conduct WBS and SSF on the same top loin steak, and that the steak taken 2.54 cm from the 13th rib is the optimal location for this combination of procedures.

Tenderness, sensory, and color attributes of two muscles from the M. quadriceps femoris when fabricated using a modified hot-boning technique.

The M. quadriceps femoris from USDA Choice (n = 12) and USDA Select (n = 12) carcasses were fabricated traditionally (COLD) or innovatively (HOT), in which the seams it shares with the top round and bottom round were separated prerigor to evaluate positional and locational effects on Warner-Bratzler shear force (WBSF), sensory attributes, and objective color. At slaughter, paired USDA Choice and USDA Select carcasses were alternately assigned either the HOT or COLD treatment. At 48 h postslaughter, subprimals were removed, vacuum-packaged, and aged for an additional 5 d. After aging, the M. quadriceps femoris was cut into 2.54-cm-thick steaks and allowed to bloom 1 h. For the M. rectus femoris (REC) and M. vastus lateralis (VAL), L* values significantly (P < 0.050) decreased when moving from the proximal to distal position within the muscle. Similarly, a* and b* values decreased in the VAL when moving from the proximal to the distal aspect. After color measurement, steaks were vacuum-packaged and frozen (-26 degrees C) until shear and sensory data were collected. Significant position (proximal to distal) and location effects (cranial to caudal) were noted for both muscles. However, treatment did not affect WBSF of the VAL. Although intramuscular variation existed, WBSF and sensory panel tenderness ratings were acceptable for the REC. Although WBSF values were greater and tenderness ratings were less than the REC, the VAL were not extremely tough and therefore could be used in enhancement applications.

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.

Effects of aging on beef chuck and loin muscles enhanced with ammonium hydroxide and salt.

The objective of this study was to determine whether aging would alter the beneficial effects (tenderness, juiciness, and flavor) of enhancing beef chuck and round steaks with a 20% solution of water, ammonium hydroxide, salt, and carbon monoxide. A randomized, complete block design was used, with 2 treatments [0% (control) and 20% (pump)], 3 aging periods (1, 2, and 3 wk), 3 muscles (M. triceps brachii from the clod heart, M. biceps femoris from the sirloin cap, and M. rectus femoris from the knuckle), and 3 replications. There were a total of 12 subprimals per treatment per aging period (n = 72 each). Individual steaks were cut to a thickness of 2.54 cm and packaged in a high-oxygen modified-atmosphere package (80% oxygen, 20% carbon dioxide). At the end of the aging period, steaks were vacuum packaged and frozen. Steaks were used to determine Warner-Bratzler shear force (WBS) and consumer sensory ratings. For all muscles, WBS values were lower for pump steaks than control at every aging period (P < 0.050). In addition, as aging period increased, WBS values for all steaks increased. Consumer taste panels revealed more desirability for tenderness, juiciness, flavor, and overall acceptability for pump steaks than control steaks. In addition, steaks aged for 1 d were more desirable than steaks aged for 7 and 14 d (P < 0.050). These data indicate that aging does not decrease the benefits (tenderness, juiciness, and flavor) of enhancement.

Effects of dark storage and retail display on beef chuck and round muscles enhanced with ammonium hydroxide, salt, and carbon monoxide.

The objective of this study was to determine the retail shelf stability of beef chuck and round muscles enhanced with ammonium hydroxide, salt, and carbon monoxide. A split plot design was used for each of 3 muscles [triceps brachii (TB), biceps femoris (BF), and rectus femoris (RF)] with 2 treatments (0 and 20% pump), 3 dark storage periods (1, 2, and 3 wk), and 3 replications in the whole plot and retail display period as the split plot. There were a total of 12 subprimals per treatment per dark storage period (n = 72 each). Individual steaks were cut to a thickness of 2.54 cm and packaged in a modified-atmosphere package (MAP). The TB was packaged in a high-oxygen MAP (80% oxygen, 20% carbon dioxide). The BF and RF were packaged in a low-oxygen MAP (100% carbon dioxide). At the completion of each dark storage period, steaks were subjected to 7 d of simulated retail display. Steaks were used for objective and subjective color measurements, total plate counts, and determination of retail purge and oxidation. For all muscles, total plate counts were always numerically greater in injected steaks. Triceps brachii steaks held in dark storage for 3 wk and displayed at retail for 4 or more days all exceeded 10(7) log of cfu/cm(2) for aerobic plate count. Biceps femoris and RF steaks packaged in a low-oxygen MAP had much lower bacterial counts, with levels below 4.2 log of cfu/cm(2), even after 7 d of retail display. Oxidation values for the TB were extremely high (ranging from 12.3 to 26.6), whereas the BF and RF had values that were much lower (< or =1.0 mg of malonaldehyde/kg of muscle), likely due to the oxidation occurring in a high-oxygen MAP for the TB. Enhanced TB steaks proved to have greater color stability (less discoloration) than nonenhanced TB steaks. In addition, the BF and RF (low-oxygen MAP) steaks had better color stability (more stable redness values) than TB (high-oxygen MAP) steaks, although TB steaks initially exhibited a brighter red color. Retail display life was enhanced by packaging in 100% carbon dioxide, and enhanced steaks exhibited greater color stability in retail display than control steaks.