Comparative effects of beta-adrenergic agonist supplementation on the yield and quality attributes of selected subprimals from calf-fed Holstein steers.

Mechanical portioning tests were performed on beef rib, strip loin, tenderloin, and top sirloin subprimals obtained from calf-fed Holstein steers to characterize the influence of zilpaterol hydrochloride (ZH), ractopamine hydrochloride (RH), or no ß-adrenergic agonist (ßAA; CON) on subprimal and steak yield. In addition, ßAA effects on tenderness, composition, and raw and cooked color of steaks from the aforementioned strip loin subprimals were characterized. At 14 to 15 d (ribs, tenderloins, and top sirloin) or 16 d (strip loin) postmortem, subprimals were portioned into steaks using a mechanical portioning machine. The appropriate variables were measured before and after portioning to determine ßAA influence on trimmed and untrimmed subprimal weight, subprimal length (rib only), steak weight and yield, and steak thickness (rib only). Steaks obtained from the strip loin subprimals were subjected to analysis of raw instrument color (L*, a*, b*), proximate composition, and pH. In addition, strip steaks were aged (16 or 23 d) before analysis of cooked internal color, Warner-Bratzler shear force (WBSF), and slice shear force (SSF). Briefly, ZH supplementation increased (P < 0.01) the weight of all subprimals when compared to CON. Furthermore, subprimals from CON animals consistently had fewer and lighter steaks (P ≤ 0.04) than subprimals from ZH-fed steers. Additionally, raw steaks from ZH cattle were a less vivid red (lower a* and saturation index values; P < 0.01) when compared to CON and RH steaks, which did not differ (P > 0.05). There was no interaction between ßAA treatment and postmortem aging length for WBSF or SSF (P > 0.10). However, CON steaks (3.25 kg) had lower WBSF values (P < 0.05) than ZH or RH steaks (3.68 and 3.67 kg, respectively). Regardless, aging for 23 d vs. 16 d resulted in decreased WBSF and SSF (P < 0.01) for all ßAA treatments. Although differences were numerically small, evaluations indicated the internal cooked surfaces of ZH and RH steaks were less red (P < 0.05) than CON steaks. Overall, these data reemphasize increased subprimal weights due to ßAA supplementation, particularly ZH. However, the data are not indicative of increased steak yield due to ßAA supplementation. Furthermore, the data demonstrate ßAA supplementation increases the shear force of calf-fed Holstein strip steaks regardless of postmortem aging period. However, no differences in shear force between the ßAA treatments (ZH or RH) were noted.

In-home consumer and shear force evaluation of steaks from the M. serratus ventralis thoracis.

The M. serratus ventralis thoracis was obtained from US Select arm chucks (n=87) to investigate if this underutilized muscle can be used as a steak alternative. Muscles were assigned randomly into three treatment groups: (1) control; (2) blade tenderization; and (3) injection, containing salt, phosphate, and papain. Steaks were cut from each muscle for in-home consumer evaluation (n=136) and Warner-Bratzler shear (WBS) force determination. The WBS values for injected steaks (13.1N) were lower (P<0.05) than for blade-tenderized (18.4N) and control (19.9N) steaks. Tenderness ratings for the injected steaks were higher (P<0.05) compared to the other treatments when steaks were grilled, oven prepared or were cooked in a skillet; however, this improvement did not significantly influence overall like scores for steaks that were oven prepared or cooked in a skillet. For the most part, degree of doneness did not significantly impact consumer evaluations of steaks prepared by the various cooking methods. However, there was a treatment x degree of doneness interaction for grilled-cooked steaks where increased doneness for blade-tenderized and injected steaks resulted in increased palatability ratings, whereas increased doneness for control steaks generally resulted in lowered palatability ratings. Consumer ratings and WBS values for the M. serratus ventralis thoracis indicate that merchandising steaks from this muscle may be a viable option in the marketplace, especially if blade tenderization or injection processes are used for further enhancement.

Effect of blade tenderization, aging time, and aging temperature on tenderness of beef longissimus lumborum and gluteus medius.

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.

Consumer acceptance and steak cutting yields of beef top sirloin and knuckle subprimals.

Beef knuckles (n=150) and center-cut top sirloin butts (n=150) were used to determine portion-controlled steak cutting yields, palatability characteristics, and consumer acceptance of rectus femoris (RF), vastus lateralis (VL), and gluteus medius (GM) steaks. Steak yields were higher (P<0.05) for top sirloins than knuckles. Trained sensory panel ratings for overall tenderness, juiciness, and flavor were similar between RF and GM. Consumer panel ratings for tenderness and juiciness were higher (P<0.05) for GM than RF; however, consumer perceptions of overall like and flavor were similar for GM and RF. Vastus lateralis received lower (P<0.05) trained panel and consumer ratings for all traits than either RF or GM. Palatability of VL will need improvement to be a viable foodservice offering. Yet, these data suggest that RF would amply substitute for GM in foodservice settings, and that knuckle steak yields would be adequate for foodservice applications.

Identifying muscle and processing combinations suitable for use as beef for fajitas.

Four different treatments-control, papain, blade tenderization, and papain+blade tenderization-were applied to sixty USDA Choice M. diaphragma pars costalis, M. transversus abdominis, M. obliquus abdominis internus, M. rhomboideus, M. trapezius, M. latissimus, and M. serratus ventralis. Trained (n=6) and consumer (n=81) panelists scored papain samples higher for most sensory traits. Treatment tended not to affect the palatability scores of the M. diaphragma pars costalis and M. serratus ventralis, which tended to receive higher scores in comparison to the other muscles. Consumers were willing to purchase the M. latissimus and M. serratus ventralis treated with papain+blade tenderization and papain, respectively, and these muscles performed well enough to be considered as alternatives in the beef fajita market.

Retail cutting characteristics for US Choice and US Select beef subprimals.

US Choice (Ch) and US Select (Se) beef subprimals from the rib, chuck, plate, loin, and round were obtained to conduct retail cutting tests. Subprimals were merchandised into bone-in or boneless retail cuts and associated components by experienced retail meat merchandisers. These Se subprimals had less (P<0.05) trimmable fat than their Ch counterparts: ball tip, top sirloin, outside round, inside round, and ribeye. Se inside rounds, outside rounds, eye of rounds, boneless striploins, and ball tips had greater (P<0.05) purge losses than the same cuts from Ch. The only subprimals where grade impacted total saleable yield were the top (inside) rounds (Ch=80.13%, Se=87.34%; P=0.004) and outside rounds cut into roasts, steaks, and cubed steaks (Ch=87.61%, Se=90.28%; P=0.05). Methods to increase retail yields from beef subprimals should consider minimizing purge and increasing cutting efficiencies in addition to reducing fat trim.

Innovative wholesale carcass fabrication and retail cutting to optimize beef value.

Innovations in beef carcass fabrication to improve subprimal yield, retail cut yield, and overall carcass value were evaluated. Alternating sides from 30 beef carcasses were assigned to either an innovative or conventional style of fabrication. The innovative method resulted in greater (P<0.001) total subprimal yield and less (P<0.001) lean trimmings from the forequarter; however, hindquarter total subprimal yield and lean trimmings were not affected (P>0.05) by fabrication style. Value was greater for the innovative forequarter (P<0.001) and hindquarter (P<0.01), and total value was increased by more than US $14 per beef carcass compared to the conventional style. Selected subprimals were evaluated in retail cutting tests. In general, the innovative retail subprimals had yields equal to or greater than the conventional subprimals. Innovative carcass fabrication may allow for greater marketing options for beef cuts to improve carcass value and to offer greater retail merchandizing opportunities.

Biochemical and physical factors affecting discoloration characteristics of 19 bovine muscles.

Steaks from muscles (n=19 from nine beef carcasses) were evaluated over the course of retail display (0-, 1-, 2-, 3-, 4- or 5-d) for objective measures of discoloration (metmyoglobin, oxymyoglobin, L*-, a*-, and b*-values), reducing ability (metmyoglobin reductase activity (MRA), resistance to induced metmyoglobin formation (RIMF), and nitric oxide metmyoglobin reducing ability (NORA)), oxygen consumption rate (OCR), oxygen penetration depth, myoglobin content, oxidative rancidity, and pH. Muscles were grouped according to objective color measures of discoloration. M. longissimus lumborum, M. longissimus thoracis, M. semitendinosus, and M. tensor fasciae latae were grouped as "high" color stability muscles, M. semimembranosus, M. rectus femoris, and M. vastus lateralis were grouped as "moderate" color stability muscles, M. trapezius, M. gluteus medius, and M. latissimus dorsi were grouped as "intermediate" color stability muscles, M. triceps brachi - long head, M. biceps femoris, M. pectoralis profundus, M. adductor, M. triceps brachi - lateral head, and M. serratus ventralis were grouped as "low" color stability muscles, and M. supraspinatus, M. infraspinatus, and M. psoas major were grouped as "very low" color stability muscles. Generally, muscles of high color stability had high RIMF, nitric oxide reducing ability, and oxygen penetration depth and possessed low OCRs, myoglobin content, and oxidative rancidity. In contrast, muscles of low color stability had high MRA, OCRs, myoglobin content, and oxidative rancidity and low RIMF, NORA, and oxygen penetration depth. Data indicate that discoloration differences between muscles are related to the amount of reducing activity relative to the OCR.