Master of Science / Department of Animal Sciences and Industry / Terry A. Houser / The objective of this study was to determine the effect of extended postmortem aging (DOA), steak location (LOC), and dietary treatment (TRT) on cooked meat tenderness, sarcomere length, and myofibrillar protein degradation of steaks from the Semitendinosus (ST) and Longissimus lumborum (LL). Crossbred feedlot steers (n = 40; initial body weight 638 ± 29 kg) were fed 45 d with the following diets: a control diet, control diet with microalgae meal, microalgae meal and antioxidants fed at the beginning of feeding, and microalgae meal with antioxidants fed during the final 10 d of feeding. The ST and LL were removed from carcasses. The ST was fabricated into 10 steaks, which were paired with an adjacent steak and assigned 5 LOC; LOC 1 was the most proximal and LOC 5 was the most distal. Each LOC was randomly assigned an aging period of 7, 14, 28, 56 or 112 d. The 6 most posterior steaks of the LL were paired with an adjacent steak and assigned 3 locations; LOC 1 being the most anterior and LOC 3 the most posterior. Each LOC of the LL was randomly assigned an aging period of 7, 28, or 112 d. Shear force, sarcomere length, muscle fiber type and size, postmortem proteolysis, and calpain activity were measured across aging periods for each LOC. Improved Warner-Bratzler shear force (WBSF) values were detected throughout the 112 d aging period for both ST and LL steaks (quadratic; P < 0.01). The largest decrease in shear force occurred between d 7 and 28 for LL and ST steaks. Shear force decreased (P < 0.01) from LOC 1 to LOC 5 (proximal to distal) in ST steaks. Steak LOC 5 had the longest sarcomeres over LOC 1, 2, and 3 on d 7, 14, and 28 (P < 0.01) in the ST; LOC 4 and 5 also had a greater percentage of Type I fibers (P < 0.01). Muscle fiber size in ST steaks decreased (P = 0.01) from LOC 1 to LOC 5. As DOA increased, intact calpain-1 decreased (quadratic; P < 0.01), with intact calpain-1 completely disappearing by d 56 and d 28 in the ST and LL, respectively. Intact desmin and troponin-T decreased throughout the 112 d in ST and LL steaks (linear; P ≤ 0.03). Degraded desmin-38 kDa increased (P < 0.01) between d 14 and d 28; however, degraded desmin-38 kDa did not continue to degrade (P = 0.76) from d 56 to d 112 in ST steaks. Degraded desmin-35 kDa content, however, continued to increase through d 112 (P < 0.01). Muscle fiber size and type along with sarcomere length played a substantial role in tenderness differences in steak LOC, whereas calpain and proteolytic activity played a substantial role across DOA.

Muscles (n = 18) were dissected from each side of twenty lamb carcasses. Muscles from the right sides of the carcasses were used to determine weight, length, width, minimum and maximum thickness, objective color measurements, water-holding capacity (WHC), pH, total collagen content, sarcomere length, and fat and moisture content. Muscles from the left sides of the carcasses were aged for seven days and used to determine percent cook loss, and Warner-Bratzler shear force values. The M. teres major was lightest (P < 0.05) in weight and smallest in surface area, while the M. longissimus lumborum was heaviest (P < 0.05) in weight, and the M. serratus ventralis was largest in surface area. M. adductor and M. semimembranosus were found to be the darkest in color (P < 0.05), while the M. latissimus dorsi and M. tensor fasciae latae were the lightest (P < 0.05). M. triceps brachii had the highest WHC and the M. longissimus lumborum the lowest. The M. teres major and M. serratus ventralis had the highest (P < 0.05) pH values. The M. infraspinatus was found to have the highest collagen content (9.00 mg/g) and the M. psoas major revealed the longest sarcomere lengths (3.06 μm). M. serratus ventralis possessed the highest (P < 0.05) percent fat and the lowest moisture content. M. serratus ventralis had the lowest cook loss (17.1%) and M. supraspinatus had the highest (25.6%). Of the muscles sampled, the M. serratus ventralis was found to have the lowest shear force value (21.8 newtons) and the M. semimembranosus had the highest (42.6 newtons). Based on the findings of these data, it is likely to conclude that certain muscles may be suitable for individual muscle applications while others may not be suitable or may pose certain palatability problems.

No description available.

Previous studies have shown that the experience of joy normally accompanies the experience of tenderness or love. Theorists have thus suggested that tenderness is not a distinct emotion, but rather a variety of joy. The present study explored whether it is possible to induce tenderness while inhibiting joy. Participants watched scenes designed to induce different emotions. Results showed that a scene could induce high levels of tenderness and low levels of joy if that scene also induced high levels of sadness. These findings suggest the need to reconsider theoretical assumptions regarding the distinction between tenderness and joy.

Steers (n = 77) and heifers (n = 68) were assigned randomly to one of three treatment groups. Treatment groups were defined as: no implant, implanted twice with trenbolone acetate (Revalor S or H), or implanted twice with estrodial benzoate (Synovex S or H). Animals were fed to an estimated 10 mm backfat thickness and based on visual appraisal, were assigned a harvest date. Carcass characteristics, color space values, sarcomere length, fat and moisture determination, Warner-Bratzler shear force, and protein degradation were all measured. Implanted animals, as a whole, exhibited heavier hot carcass weights and larger ribeye areas than non-implanted animals. Animals implanted with Revalor displayed significantly lower marbling scores and lower yield grades than those from control or Synovex groups. The distribution of quality grades within treatment groups shifted, with implant groups displaying higher percentages of Select carcasses. Gender impacted percentage of extractable fat and marbling scores, with heifers displaying higher values than steers for both measurements. Both implant groups displayed higher (P < 0.05) Warner-Bratzler shear values following a 0- and 14-d aging periods. However, following the 21-d aging period, differences in tenderness were no longer present between non-implanted and implanted animals. Synovex treated animals displayed longer (P < 0.01) sarcomere lengths than control or Revalor. Differences (P < 0.001) in protein degradation were found between treatment groups. Across gender groups, the non-implanted cattle displayed the greatest amount of degradation (62%), followed by Synovex (48%,) and lastly Revalor (33%), all of which were different (P < .05) from each other. These results indicate that use of anabolic implants positively impacted lean muscle growth, yet was a detriment to quality. Also, tenderness was negatively impacted by the use of these compounds. However, this study found by aging product for at least 21 days, tenderness differences between implanted and non-implanted animals were significantly mitigated.

The effect of feeding Zilpaterol hydrochloride (ZH) with a 3 or 10 d withdrawal (WD) period to calf-fed Holstein steers (N=2993) on carcass characteristics and tenderness were evaluated in a feed lot experiment. Cattle were fed 0 or 8.3 mg/kg of ZH for the final 20 d of the feeding period, each treatment level was assigned a WD period of either 3 or 10 d. Treatment groups consisted of Control 3 d WD (C3) and 10 d WD (C10), and ZH fed 3 day WD (Z3) and 10 d WD (Z10). Cattle were slaughtered at a commercial facility, carcasses chilled for at least 40 hours and carcass characteristics evaluated by trained personnel. Loins (n=60) were randomly selected from each treatment group for Warner Bratzler Shear (WBS) analysis. Rib-eye area (REA) increased 3.8 cm2 for ZH fed 3 day WD cattle (P<0.01) when compared to control, and 5.4 cm2 for ZH fed 10 day withdrawal cattle (P<0.01) when compared to control. There was no significant difference in REA between ZH fed 3 and 10 d WD periods (P>0.05). A trend was observed for ZH fed 10 d WD cattle to have an increased hot carcass weight when compared to control (P=0.0589), while there was no significant difference for cattle fed ZH with a 3 day WD (P=0.3763) comparatively. There was no difference in ZH fed cattle when compared to control on; kidney pelvic and heart fat %, adjusted preliminary yield grade, calculated yield grade, marbling score, or lean and bone maturity (P>0.05). There was an increase in WBS for ZH fed cattle when compared to control for Choice 7 d and 14 d aged steaks for both WD periods. Choice Z10 steaks aged 21 d showed an increase in WBS (P<0.05) while the Z3 had no effect. Select Z3 7 d aged steaks had higher WBS when compared to control while Z10 had no effect. Oppositely, the Select Z10 14 d aged steaks had increased WBS while the Z3 had no effect. There was no difference in Select 21 d aged steaks. There was no difference in WBS between the Z3 and Z10 for any of the aging periods. Feeding Zilpaterol hydrochloride for 20 d increased carcass leanness while having little effect on carcass fat of calf-fed Holstein steers. There was no difference observed between 3 d and 10 d WD period. Zilpaterol hydrochloride treatment decreased steak tenderness, although as aging progressed there little to no difference between steaks from ZH fed and control cattle.

Breast muscles that are deboned prior to 4 to 6 h postmortem are highly variable and lacking in tenderness. The poultry industry currently provides costly storage space for intact broiler breasts during this 4 to 6 h period. This thesis evaluates tenderization techniques that if effective could eliminate the need for this additional 4 to 6 h storage time. The first objective of this study was to determine a relationship between Warner-Bratzler shear values (WBS) (1 cm by 1cm, variable length strips) and consumer tenderness acceptability of broiler breasts. The breasts were divided into five groups based on their WBS values. Consumers were presented with one sample (1 cm by 1 cm by 2 cm strips) at a time and asked to report the acceptability of the sample's tenderness on a 9-point hedonic scale. Of the 62 panelists, 93.5 % found chicken breasts with WBS values from 2.1 to 3.1 kg to be acceptable. Only 83.9 % of the panelists found the extremely tender chicken breast to be acceptable (1.1 to 1.9 kg). The percentage of consumers that found the samples acceptable decreased as the WBS values increased beyond 3.1 kg (P<0.05). The second objective determined the effects of high pressure hydrodynamic shockwave (HSW) on tenderness (48 h postmortem) of early-deboned (52 min postmortem) breasts treated 25 minutes after deboning (70 min postmortem) or treated after storage (24 hr postmortem) and compared to the corresponding non-treated companion breasts. The effect of HSW treatment on early-deboned treated 25 min after deboned broiler breasts was determined by the following methods. Live broiler chickens were obtained from a commercial poultry company and slaughtered according to commercial processing standards. The effect of HSW on early deboned stored broiler breast was examined by deboning broiler breasts 45 min postmortem and storing (4 C) for 24 h. One breast from each bird was treated with hydrodynamic shockwave, while the companion breast was used as a control. Packaged breasts were placed in the center of a 20.23 cm diameter cylinder which was vertically positioned in the bottom of a water-filled HSW hemishell tank (30.4 cm diameter) and a shockwave was produced by and a shockwave was produced by detonating 40 grams of molecular explosive in the water. Early deboned (ED) breasts stored 24 h before treatment (2.5 kg, WBS) were 42% more tender than the companion ED control breasts (4.3 kg, WBS). The HSW treated breasts would be acceptable to approximately 94 % of consumers. The ED control breasts would be acceptable to only 67.7% of consumers. Early deboned and treated 25 min after deboning breasts (5.0 kg) were not different in WBS from their companion ED control breasts (4.6 kg). Early-deboned breasts treated immediately may require higher pressure shockwaves or delayed treatment. The HSW process can overcome the problem with tenderness associated with early deboning if the breasts are processed after storage thereby providing processors with the option to debone earlier. A third objective was to examine the effects of electrically produced shockwaves on early deboned broiler breasts and normally processed turkey breast. Broiler breasts were treated with one Pulse Firing Network (PFN) or two PFN and 45 % Energy. Breasts treated with one PFN were not different than controls. Broiler breasts exposed to two PFN were 22 % more tender and different from the controls. Turkey breast portions exposed to two PFN and 72% Energy were different (12 % lower WBS values) from the control breast portion. Electrically produced shockwaves can tenderize stored, early deboned chicken breasts and aged turkey breasts. / Master of Science

The objectives of this study were to investigate the different characteristics of the newly introduced breed, Waguli (Wagyu x Tuli) when comparing it with the Brahman breed. Twenty-four animals were used. Six steers of each breed were fed 94% concentrate diet (94C) and the other six were fed 86% concentrate diet (86C). Eight steers, two from each group, each were harvested at 128 days, 142 days, and 156 days on feed. Feedlot performance data indicated that Waguli steers were highly efficient (P < 0.05) and gained more than Brahman steers on a daily basis (P < 0.05). Carcass characteristic data showed that Waguli steers have larger ribeye area with more 12th rib fat thickness, marbling score and higher quality grade (P < 0.05). It is well known that Wagyu is a highly marbled and tender Japanese breed. It was found that the reason for the Waguli tenderness and low shear force values to be the low level of calpastatin activity (P < 0.05), the inhibitor of the postmortem proteolytic enzyme-calpain. While the toughness of the Brahman meat was due to the high level of calpastatin activity. The calpain activity did not differ between the two breeds. Shear force values agreed with the calpain and calpastatin activities data, in which the Waguli steaks showed less shear force values at day 7 and 10 postmortem than the Brahman steaks (P < 0.05). However, at day 14 postmortem there was no difference in shear force values between the two breeds (P < 0.05). Fatty acid data analysis indicated that Waguli steers had a profile with less saturated fatty acids (SFA) and more unsaturated fatty acids (UFA) content than those in Brahman steers fat. Looking at the ratio of unsaturated fatty acids (UFA) to saturated fatty acids (SFA), it is observed that Waguli steers had a greater ratio than Brahman steers. In conclusion, Waguli steers produce tender meat with good marbling ability, which likely to satisfy the consumers demand. In addition, they have a desirable average daily gain and feed efficiency with high polyunsaturated fatty acids comparatively with Brahman steers.

Temperament effects on meat quality were investigated using three contemporary groups consisting of Bonsmara-sired yearling-fed (n = 31), Angus-sired calf-fed (n = 49), and Angus-sired yearling-fed (n = 48) steers. To evaluate temperament, exit velocity, pen scores, and chute scores were determined before shipment to the feedlot, and exit velocity was measured on arrival to the feedlot and after approximately 70 d on feed. Serum cortisol concentration was determined at each evaluation and before slaughter. At slaughter, pH and temperature were monitored in the M. longissimus lumborum. USDA yield and quality grade factors and CIE color space values were determined, and M. longissimus lumborum steaks were evaluated for sarcomere length, 72-h calpastatin activity, proximate composition, and Warner-Bratzler shear force (WBS) values 3, 7, 14, and 21 d postmortem. Temperament categories were based on rankings within contemporary groups at each evaluation. Temperament traits were consistent across evaluations, and values decreased (P < 0.05) in magnitude over time. Relationships between temperament traits were consistent across contemporary groups. Increasing excitability was associated with higher (P < 0.05) serum cortisol concentration. Body weight was slightly lower (P < 0.05) in cattle with excitable temperaments at all evaluations. Carcass characteristics, proximate composition, muscle color, and calpastatin activity were unaffected by temperament. Carcasses from cattle with calm temperaments had higher 0.5 h postmortem pH values than those from intermediate and excitable cattle (0.1 and 0.2 units, respectively). The Angus-sired yearling-fed steers classified as Excitable had higher (P < 0.05) WBS values than the calmer Angus-sired, yearling-fed steers. This trend was observed in the Bonsmara-sired steers, although the values were not statistically different. No differences attributable to temperament were apparent in the Angus-sired calf-fed steers. Correlations were highest between temperament values and tenderness after 21 d. Yearling-fed cattle classified as Excitable before shipment to the feedlot produced tougher (P < 0.05) steaks than those from calmer animals. At evaluations later in production, Calm steers produced tougher (P < 0.05) steaks. Tenderness did not differ across temperament categories in calf-fed steers regardless of sorting time. These data indicate temperament influences tenderness, though the mechanism is not clear.

Beef retail steaks from establishments in twelve US cities and beef foodservice steaks from establishments in five US cities were evaluated using Warner-Bratzler shear and consumer sensory panels. Postmortem aging times for retail establishments ranged from 1 to 358 d with a mean of 20.5 d, and those from foodservice establishments aging times ranged from 9 to 67 d with an average of 15.9 d. For retail, top blade had the lowest (P < 0.05) WBS values, while cuts from the round top round and bottom round had the highest (P < 0.05) WBS values. Top loin and ribeye steaks had the lowest (P < 0.05) WBS values compared to top sirloin foodservice steaks. Retail top blade steaks received the highest (P < 0.05) ratings by consumers for overall like, tenderness level, like tenderness, juiciness level, and like juiciness; and foodservice top loin steaks received the highest (P < 0.05) for tenderness level, like tenderness, flavor level, juiciness level, and like juiciness. USDA quality grade did have an effect on foodservice ribeye and top sirloin steaks for sensory panels. Prime foodservice ribeye steaks were rated highest (P < 0.05) for overall like, like tenderness, tenderness level, like juiciness, and juiciness level, whereas ungraded ribeye steaks were rated lowest (P < 0.05) for like tenderness and tenderness level. Ungraded foodservice top sirloin steaks were rated highest (P < 0.05) for overall like, like tenderness, like flavor, and like juiciness. Additional improvements to reduce the range of tenderness levels are necessary to increase consumer acceptability.