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Trained panel evaluation of grilled strip loin steaks from grain-finished cull cows
Abstracts
Conclusion: Although measurements of calpastatin and calpain 1 activity were not affected by growth promotant technologies used in this study, the lesser accumulation of troponin-T degradation products in beef from cattle fed ZH indicate a mechanism for a decrease in protein degradation that may affect beef tenderness. Interestingly, the measured differences in calpain 2 activity indicate a possible role in post-mortem aging. Additionally, changes in protein degradation across a retail cut indicate that variation does occur across a single muscle that may impact overall quality factors.
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steaks LD and PM steaks had (P b 0.05) the lowest total moisture losses; and fresh GM steaks had (P b 0.05) lower total moisture losses than fresh BF steaks. For previously frozen steaks, LD steaks had (P b 0.05) the lowest total moisture losses; and PM steaks had (P b 0.05) lower total moisture losses than ST, GM, and BF steaks. Conclusion: Extended aging (21 vs 7 d) of steaks improves tenderness (lower WBSF), but increases total moisture losses. Freezing steaks has minimal impact on WBSF for hindquarter muscles. Therefore, when designing research protocols, it is acceptable to freeze samples prior to analysis.
Keywords: Aging, Beef, Calpain, Implants, Zilpaterol Hydrochloride Keywords: Aging, Beef, Freezing, Fresh, Shear force doi:10.1016/j.meatsci.2015.08.094 doi:10.1016/j.meatsci.2015.08.095 Meat and Poultry Quality 75 Effects of postmortem age and freezing on Warner-Bratzler shear force of six muscles from the beef hindquarter R. Mcewana,⁎, J. Unruha, T. Housera, T. O'Quinna, N. Bloedowb, C. Vahlb, S. Strodaa, aAnimal Science and Industry, Manhattan, United States, b Statistics, Kansas State University, Manhattan, United States Objectives: When designing research protocols, samples for Warner-Bratzler shear force (WBSF) are often frozen for later sanalysis. Previous research has been inconclusive as to the effect of freezing on WBSF of beef steaks. Therefore, the objective of this experiment was to determine the effects of postmortem aging time and freezing on WBSF of six muscles from the beef hindquarter. Materials and methods: Choice strip loin (IMPS # 180), tenderloin (IMPS # 189A), top sirloin butt (IMPS # 184), inside round (IMPS # 168), eye of round (IMPS # 171C), and round flat (IMPS # 171B) subprimals (n = 18 / muscle) with a common slaughter date were purchased from a commercial processing facility. Longissimus dorsi (LD), psoas major (PM), gluteus medius (GM), semimembranosis (SM), semitendenosis (ST), and biceps femoris (BF) muscles from the respective subprimals were fabricated into four 2.54-cm steaks from the center of the muscle, vacuum packaged, and randomly assigned to treatments of status (fresh or frozen), and 7 or 21 d of aging. At the end of the designated aging time (7 or 21 d), fresh treatment steaks were cooked and frozen treatment steaks were blast frozen at -40 °C for one week, and thawed for 12 h in refrigerated (3 ± 1 °C) storage prior to cooking. All steaks were cooked in a convection oven (163 °C) to an internal temperature of 70 °C. Cooked steaks were stored overnight in refrigerated storage (0 ± 1 °C) before eight core samples were taken parallel to the muscle fiber orientation from each steak. Cores were sheared using an Instron model 5569 Universal Testing Machine fitted with a WBSF blade attachment. Purge and cooking losses were measured to calculate total moisture losses. Data were analyzed using a completely randomized design, where the whole plot was muscle, and the split plots were aging time and status, using the MIXED (total moisture loss) and GLIMMIX (WBSF) procedures of SAS 9.4. Results: Steaks aged 21 d had (P b 0.05) lower WBSF than steaks aged 7 d. In a muscle × status interaction (P = 0.02), previously frozen LD steaks tended to have lower (P = 0.07) WBSF than fresh LD steaks. For fresh steaks, PM steaks had (P b 0.05) the lowest WBSF, LD steaks had (P b 0.05) lower WBSF than ST, SM, and BF steaks, and GM steaks had (P b 0.05) lower WBSF than BF steaks. For previously frozen steaks, PM steaks had (P b 0.05) the lowest WBSF. In addition, LD steaks had (P b 0.05) lower WBSF than GM, SM, ST, and BF steaks; and GM steaks had (P b 0.05) lower WBSF than ST and BF steaks. Steaks aged 7 d had (P b 0.05) lower total moisture losses than steaks aged 21 d. In a muscle × status interaction (P = 0.002), previously frozen steaks from the GM, PM, and ST had (P b 0.05) greater moisture losses than fresh GM, PM, and ST steaks. For fresh
Meat and Poultry Quality 76 Trained panel evaluation of grilled strip loin steaks from grain-finished cull cows R.D. Crownovera,⁎, D.A. Cashmana, T.G. O'Quinnb, R.J. Rathmanna, J.C. Brooksa, M.F. Millera, aAnimal and Food Sciences, Texas Tech University, Lubbock, bAnimal Sciences and Industry, Kansas State University, Manhattan, United States Objectives: A trained sensory panel was conducted to compare the palatability traits of beef strip loins with similar marbling scores from A-maturity carcasses and mature, grain-finished cull cows. Materials and methods: Treatments included strip loins with USDA marbling scores of Slightly Abundant and greater (SLAB+), Modest and Moderate (MT/MD), Small (SM), Slight (SL), and Traces and Practically Devoid (TR/PD) of youthful, “A” maturity carcasses (Y) and carcasses from mature (M) cattle (C or greater maturity). Fifteen subprimals from each treatment were selected by Texas Tech University personnel, and were aged 21 d under vacuum at 2 to 4 °C. Strip loins were cut into 2.5 cm thick steaks, frozen and stored at -20 °C until sensory evaluation. Steaks were thawed for 24 h at 2 to 4 °C and cooked on a gas radiant broiler (model IRB-36, Imperial Commercial Cooking Equipment, Corona, CA) to a medium degree of doneness (71 °C) monitored by a digital meat thermometer (Digi-Sense Type J, Cole-Parmer Instrument Company Vernon Hills, IL). Following a 3 min rest period, steaks were portioned into cubes (1 cm3) and served to panelists. Samples were evaluated by a seven member trained panel for initial juiciness, sustained juiciness, initial tenderness, sustained tenderness, beef flavor, and flavor intensity on a 10 cm, verbally anchored line-scale (0 = extremely dry/tough/ unbeef-like; 100 = extremely juicy/tender/beef-like). Seven samples were served in each of the 15 panel sessions. Results: Samples from Y-SLAB+ rated greatest (P b 0.05) for initial juiciness, sustained juiciness, initial tenderness, sustained tenderness, beef flavor, and flavor intensity. Also, M-TR/PD rated lowest (P b 0.05) for initial juiciness, initial tenderness, sustained tenderness, beef flavor, and flavor intensity. Young cattle rated more desirable (P b 0.05) for both initial tenderness and sustained tenderness when compared to mature cattle with the same marbling score. Strips from Y-SLAB+ and M-SLAB+ rated greatest (P b 0.05) in beef flavor and flavor intensity. Furthermore, M-SLAB+ rated greater (P b 0.05) for initial juiciness and sustained juiciness when compared to samples from all lower marbling scores regardless of maturity. Initial juiciness, initial tenderness, sustained tenderness, beef flavor, and flavor intensity were rated greater (P b 0.05) for strips from Y-TR/PD when compared to M-TR/PD. Moreover, M-MT/MD rated greater (P b 0.05) in initial juiciness and sustained juiciness when compared to Y-SM. In addition, between M-MT/ MD and Y-SM values were rated similar (P b 0.05) for sustained tenderness and flavor intensity. Finally, sustained juiciness, beef flavor, and flavor intensity were rated similar (P b 0.05) between Y-SL and M-SL.
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Abstracts
Conclusion: These results indicate cull cows fed a high concentrate diet prior to harvest with carcasses possessing SLAB+ marbling scores could provide a similar eating experience to “A” maturity carcasses of lower marbling scores. Therefore, these results indicate the opportunity to market these beef items with higher premiums than are currently received.
(P b 0.05) for PC, BPC1, BPC2, and NS steaks than C steaks; and PC steaks had lower (P b 0.05) cooking losses than BN steaks. Summer steaks had lower (P b 0.05) cooking losses than spring steaks. Conclusion: Higher quality top loin steaks generally have greater amounts of marbling, are more tender (lower WBSF) and are more consistent in tenderness throughout the year than lower quality steaks.
Keywords: Beef, Maturity, palatability, trained panel, USDA quality grades
Keywords: beef, retail, season, shear force, steak
doi:10.1016/j.meatsci.2015.08.096
doi:10.1016/j.meatsci.2015.08.097
Meat and Poultry Quality 77 Characteristics of top loin steaks purchased at multiple retail grocery store outlets A. Collins⁎, J. Unruh, T. Houser, S. Stroda, Kansas State University, Manhattan, United States
Meat and Poultry Quality 78 Effects of varying corn or soybean co-product inclusion in finishing diets of feedlot heifers on carcass characteristics, fresh and processed meat quality M. Nelson⁎, J. Johnston, A. DiCostanzo, R. Cox, Animal Science, University of Minnesota - Twin Cities, St. Paul, United States
Objectives: Consumers have the opportunity to purchase steaks consisting of different quality grades from different retail outlets that may vary in tenderness. Therefore, the purpose of this study was to determine Warner-Bratzler shear force (WBSF) and cooking characteristics of top loin (strip) steaks available for purchase from selfserve display cases in grocery store outlets throughout the year. Materials and methods: Self-serve display steaks (n = 311) were purchased from four local grocery stores. Six steak types were purchased weekly from March, 2014 through February, 2015. They included branded Premium Choice (BPC1), branded Premium Choice from a second store (BPC2), Premium Choice steaks from a third store (PC), Choice steaks (C), non-grade specified steaks (NS), and branded natural (BN) steaks. The Premium Choice specifications required modest or higher marbling. The fifty-two weekly observations for each steak type were divided into four seasons of spring (March-May), summer (JuneAugust), fall (September-November), or winter (December-February) for analysis. The day following the purchase, steaks were cooked using a Blodgett (model DFC-102 CH3) convection oven preheated to 163 °C. Steak temperatures were monitored using a Doric temperature recorder attached to copper-constantan thermocouples. Thermocouples were placed in the geometric center of the steak, and steaks were removed from the oven once they reached an internal temperature of 70 °C. Steaks were then held at a refrigerated temperature (2-4 °C) for at least 12 hours prior to coring (8 cores per steak) and shearing. Steaks were cored parallel to the muscle fiber orientation using a 1.27-cm corer, and sheared using an Instron Universal Testing Machine (model 5569) with a WarnerBratzler shear force V-shaped blade attachment. Cooking losses and time were recorded for each steak. Data were analyzed as a completely randomized design with a 6 (steak type) x 4 (season) factorial arrangement of treatments using the Mixed procedure of SAS 9.3. Results: As expected, top loin steaks with higher quality classifications generally had more observed marbling than those with lower quality classifications (PC and BPC1 N BPC2 N C N NS N BN, P b 0.05). In a steak type x season interaction (P = 0.03) for WBSF, C steaks during the winter had lower (P b 0.05) WBSF values than those during summer and fall. For NS steaks, winter steaks had lower (P b 0.05) WBSF values than spring steaks. For BN steaks, summer steaks had lower (P b 0.05) WBSF values than spring and winter steaks. During the spring, PC and BPC1 had lower (P b 0.05) WBSF values than NS and BN; and BPC2 had lower (P b 0.05) WBSF values than NS. For summer, PC, BN, and BPC1 had lower (P b 0.05) WBSF values than C. For fall, BPC2 had lower (P b 0.05) WBSF values than NS, BN, and C; and BPC1 had lower (P b 0.05) WBSF values than C steaks. For winter, PC, BPC1, BPC2, and C steaks had lower WBSF values than BN steaks. Percentages of cooking loss were lower
Objectives: The impact of using corn or soybean co-product in high or low corn grain finishing diets of feedlot heifers was evaluated using forty-four purebred Limousin heifers. Materials and methods: Heifers were randomly assigned to one of four dietary treatments (11 per treatment) that included: 65% corn grain diet with 20% modified distillers grains with solubles (HI + MDGS); 65% corn grain diet with a combination of 15.2 % soy glycerin and soybean hulls (HI + SOY); 25% corn grain diet with 60% MDGS (LO + MDGS); or 25% corn grain diet with 40% MDGS and 15.2% SOY (LO + MDGS + SOY). All heifers received melengestrol acetate and Rumensin. Experimental unit was individual heifer, as all animals were fed individually using a Calan gate system. Heifers were fed finishing diets for 129 d and were humanely harvested at a commercial facility. Hot carcass weight (HCW); 12th rib back fat (BF); rib eye area (REA); percent kidney, pelvic, and heart fat (KPH); and marbling score were collected 48 h postmortem by trained plant personnel. Strip loins (IMPS #180) were collected and fabricated into 2.54 cm steaks for evaluation of drip loss, Warner– Bratzler shear force, retail shelf life evaluation (subjective and objective), and sensory evaluation. Shoulder clods (IMPS #114) were collected and ground twice (0.375 cm plate) to create ground beef and bologna, both of which were evaluated for retail shelf life (subjective and objective). Results: There was no treatment effect for HCW (P = 0.37), BF (P = 0.10), REA (P = 0.63), KPH (P = 0.67), or marbling score (P = 0.18). Drip loss did not differ among treatments (P = 0.85). Warner–Bratzler shear force values of steaks from HI + SOY were lower (3.17 kg) than LO + MDGS + SOY (3.79 kg; P = 0.02). Treatment did not affect subjective scores for lean color (P = 0.06), surface discoloration (P = 0.19), and overall appearance (P = 0.52) or objective scores for L* (P = 0.32), a* (P = 0.41), and b* (P = 0.25) of steaks. Treatment did not affect overall liking (P = 0.59), flavor liking (P = 0.78), texture liking (P = 0.38), juiciness (P = 0.56), or off flavor (P = 0.89) of steaks. Subjective toughness ratings of steaks from HI + MDGS were higher than LO + MDGS (10.54 and 9.11 respectively; P = 0.02). L* values for 25% corn diets were higher than 65% corn diets (P b 0.01) in ground beef. Treatment did affect surface discoloration (P b 0.01) in ground beef, with HI + SOY having the highest subjective value (6.21). Treatment affected surface discoloration (P = 0.01) in ground beef, with HI + SOY having the highest mean subjective value (6.21). Treatment did have an effect on overall appearance (P = b.01) in ground beef, with HI + SOY having the highest mean subjective value (4.20). Treatment had no effect on a* (P = 0.62) or b* (P = 0.43) in ground beef. Treatment did not affect lean color (P = 1.00) or overall appearance (P = 1.00) subjective mean values or a* (P = 0.89) or b* (P = 0.82) in bologna.
Conclusion: Although measurements of calpastatin and calpain 1 activity were not affected by growth promotant technologies used in this study, the lesser accumulation of troponin-T degradation products in beef from cattle fed ZH indicate a mechanism for a decrease in protein degradation that may affect beef tenderness. Interestingly, the measured differences in calpain 2 activity indicate a possible role in post-mortem aging. Additionally, changes in protein degradation across a retail cut indicate that variation does occur across a single muscle that may impact overall quality factors.
143
steaks LD and PM steaks had (P b 0.05) the lowest total moisture losses; and fresh GM steaks had (P b 0.05) lower total moisture losses than fresh BF steaks. For previously frozen steaks, LD steaks had (P b 0.05) the lowest total moisture losses; and PM steaks had (P b 0.05) lower total moisture losses than ST, GM, and BF steaks. Conclusion: Extended aging (21 vs 7 d) of steaks improves tenderness (lower WBSF), but increases total moisture losses. Freezing steaks has minimal impact on WBSF for hindquarter muscles. Therefore, when designing research protocols, it is acceptable to freeze samples prior to analysis.
Keywords: Aging, Beef, Calpain, Implants, Zilpaterol Hydrochloride Keywords: Aging, Beef, Freezing, Fresh, Shear force doi:10.1016/j.meatsci.2015.08.094 doi:10.1016/j.meatsci.2015.08.095 Meat and Poultry Quality 75 Effects of postmortem age and freezing on Warner-Bratzler shear force of six muscles from the beef hindquarter R. Mcewana,⁎, J. Unruha, T. Housera, T. O'Quinna, N. Bloedowb, C. Vahlb, S. Strodaa, aAnimal Science and Industry, Manhattan, United States, b Statistics, Kansas State University, Manhattan, United States Objectives: When designing research protocols, samples for Warner-Bratzler shear force (WBSF) are often frozen for later sanalysis. Previous research has been inconclusive as to the effect of freezing on WBSF of beef steaks. Therefore, the objective of this experiment was to determine the effects of postmortem aging time and freezing on WBSF of six muscles from the beef hindquarter. Materials and methods: Choice strip loin (IMPS # 180), tenderloin (IMPS # 189A), top sirloin butt (IMPS # 184), inside round (IMPS # 168), eye of round (IMPS # 171C), and round flat (IMPS # 171B) subprimals (n = 18 / muscle) with a common slaughter date were purchased from a commercial processing facility. Longissimus dorsi (LD), psoas major (PM), gluteus medius (GM), semimembranosis (SM), semitendenosis (ST), and biceps femoris (BF) muscles from the respective subprimals were fabricated into four 2.54-cm steaks from the center of the muscle, vacuum packaged, and randomly assigned to treatments of status (fresh or frozen), and 7 or 21 d of aging. At the end of the designated aging time (7 or 21 d), fresh treatment steaks were cooked and frozen treatment steaks were blast frozen at -40 °C for one week, and thawed for 12 h in refrigerated (3 ± 1 °C) storage prior to cooking. All steaks were cooked in a convection oven (163 °C) to an internal temperature of 70 °C. Cooked steaks were stored overnight in refrigerated storage (0 ± 1 °C) before eight core samples were taken parallel to the muscle fiber orientation from each steak. Cores were sheared using an Instron model 5569 Universal Testing Machine fitted with a WBSF blade attachment. Purge and cooking losses were measured to calculate total moisture losses. Data were analyzed using a completely randomized design, where the whole plot was muscle, and the split plots were aging time and status, using the MIXED (total moisture loss) and GLIMMIX (WBSF) procedures of SAS 9.4. Results: Steaks aged 21 d had (P b 0.05) lower WBSF than steaks aged 7 d. In a muscle × status interaction (P = 0.02), previously frozen LD steaks tended to have lower (P = 0.07) WBSF than fresh LD steaks. For fresh steaks, PM steaks had (P b 0.05) the lowest WBSF, LD steaks had (P b 0.05) lower WBSF than ST, SM, and BF steaks, and GM steaks had (P b 0.05) lower WBSF than BF steaks. For previously frozen steaks, PM steaks had (P b 0.05) the lowest WBSF. In addition, LD steaks had (P b 0.05) lower WBSF than GM, SM, ST, and BF steaks; and GM steaks had (P b 0.05) lower WBSF than ST and BF steaks. Steaks aged 7 d had (P b 0.05) lower total moisture losses than steaks aged 21 d. In a muscle × status interaction (P = 0.002), previously frozen steaks from the GM, PM, and ST had (P b 0.05) greater moisture losses than fresh GM, PM, and ST steaks. For fresh
Meat and Poultry Quality 76 Trained panel evaluation of grilled strip loin steaks from grain-finished cull cows R.D. Crownovera,⁎, D.A. Cashmana, T.G. O'Quinnb, R.J. Rathmanna, J.C. Brooksa, M.F. Millera, aAnimal and Food Sciences, Texas Tech University, Lubbock, bAnimal Sciences and Industry, Kansas State University, Manhattan, United States Objectives: A trained sensory panel was conducted to compare the palatability traits of beef strip loins with similar marbling scores from A-maturity carcasses and mature, grain-finished cull cows. Materials and methods: Treatments included strip loins with USDA marbling scores of Slightly Abundant and greater (SLAB+), Modest and Moderate (MT/MD), Small (SM), Slight (SL), and Traces and Practically Devoid (TR/PD) of youthful, “A” maturity carcasses (Y) and carcasses from mature (M) cattle (C or greater maturity). Fifteen subprimals from each treatment were selected by Texas Tech University personnel, and were aged 21 d under vacuum at 2 to 4 °C. Strip loins were cut into 2.5 cm thick steaks, frozen and stored at -20 °C until sensory evaluation. Steaks were thawed for 24 h at 2 to 4 °C and cooked on a gas radiant broiler (model IRB-36, Imperial Commercial Cooking Equipment, Corona, CA) to a medium degree of doneness (71 °C) monitored by a digital meat thermometer (Digi-Sense Type J, Cole-Parmer Instrument Company Vernon Hills, IL). Following a 3 min rest period, steaks were portioned into cubes (1 cm3) and served to panelists. Samples were evaluated by a seven member trained panel for initial juiciness, sustained juiciness, initial tenderness, sustained tenderness, beef flavor, and flavor intensity on a 10 cm, verbally anchored line-scale (0 = extremely dry/tough/ unbeef-like; 100 = extremely juicy/tender/beef-like). Seven samples were served in each of the 15 panel sessions. Results: Samples from Y-SLAB+ rated greatest (P b 0.05) for initial juiciness, sustained juiciness, initial tenderness, sustained tenderness, beef flavor, and flavor intensity. Also, M-TR/PD rated lowest (P b 0.05) for initial juiciness, initial tenderness, sustained tenderness, beef flavor, and flavor intensity. Young cattle rated more desirable (P b 0.05) for both initial tenderness and sustained tenderness when compared to mature cattle with the same marbling score. Strips from Y-SLAB+ and M-SLAB+ rated greatest (P b 0.05) in beef flavor and flavor intensity. Furthermore, M-SLAB+ rated greater (P b 0.05) for initial juiciness and sustained juiciness when compared to samples from all lower marbling scores regardless of maturity. Initial juiciness, initial tenderness, sustained tenderness, beef flavor, and flavor intensity were rated greater (P b 0.05) for strips from Y-TR/PD when compared to M-TR/PD. Moreover, M-MT/MD rated greater (P b 0.05) in initial juiciness and sustained juiciness when compared to Y-SM. In addition, between M-MT/ MD and Y-SM values were rated similar (P b 0.05) for sustained tenderness and flavor intensity. Finally, sustained juiciness, beef flavor, and flavor intensity were rated similar (P b 0.05) between Y-SL and M-SL.
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Abstracts
Conclusion: These results indicate cull cows fed a high concentrate diet prior to harvest with carcasses possessing SLAB+ marbling scores could provide a similar eating experience to “A” maturity carcasses of lower marbling scores. Therefore, these results indicate the opportunity to market these beef items with higher premiums than are currently received.
(P b 0.05) for PC, BPC1, BPC2, and NS steaks than C steaks; and PC steaks had lower (P b 0.05) cooking losses than BN steaks. Summer steaks had lower (P b 0.05) cooking losses than spring steaks. Conclusion: Higher quality top loin steaks generally have greater amounts of marbling, are more tender (lower WBSF) and are more consistent in tenderness throughout the year than lower quality steaks.
Keywords: Beef, Maturity, palatability, trained panel, USDA quality grades
Keywords: beef, retail, season, shear force, steak
doi:10.1016/j.meatsci.2015.08.096
doi:10.1016/j.meatsci.2015.08.097
Meat and Poultry Quality 77 Characteristics of top loin steaks purchased at multiple retail grocery store outlets A. Collins⁎, J. Unruh, T. Houser, S. Stroda, Kansas State University, Manhattan, United States
Meat and Poultry Quality 78 Effects of varying corn or soybean co-product inclusion in finishing diets of feedlot heifers on carcass characteristics, fresh and processed meat quality M. Nelson⁎, J. Johnston, A. DiCostanzo, R. Cox, Animal Science, University of Minnesota - Twin Cities, St. Paul, United States
Objectives: Consumers have the opportunity to purchase steaks consisting of different quality grades from different retail outlets that may vary in tenderness. Therefore, the purpose of this study was to determine Warner-Bratzler shear force (WBSF) and cooking characteristics of top loin (strip) steaks available for purchase from selfserve display cases in grocery store outlets throughout the year. Materials and methods: Self-serve display steaks (n = 311) were purchased from four local grocery stores. Six steak types were purchased weekly from March, 2014 through February, 2015. They included branded Premium Choice (BPC1), branded Premium Choice from a second store (BPC2), Premium Choice steaks from a third store (PC), Choice steaks (C), non-grade specified steaks (NS), and branded natural (BN) steaks. The Premium Choice specifications required modest or higher marbling. The fifty-two weekly observations for each steak type were divided into four seasons of spring (March-May), summer (JuneAugust), fall (September-November), or winter (December-February) for analysis. The day following the purchase, steaks were cooked using a Blodgett (model DFC-102 CH3) convection oven preheated to 163 °C. Steak temperatures were monitored using a Doric temperature recorder attached to copper-constantan thermocouples. Thermocouples were placed in the geometric center of the steak, and steaks were removed from the oven once they reached an internal temperature of 70 °C. Steaks were then held at a refrigerated temperature (2-4 °C) for at least 12 hours prior to coring (8 cores per steak) and shearing. Steaks were cored parallel to the muscle fiber orientation using a 1.27-cm corer, and sheared using an Instron Universal Testing Machine (model 5569) with a WarnerBratzler shear force V-shaped blade attachment. Cooking losses and time were recorded for each steak. Data were analyzed as a completely randomized design with a 6 (steak type) x 4 (season) factorial arrangement of treatments using the Mixed procedure of SAS 9.3. Results: As expected, top loin steaks with higher quality classifications generally had more observed marbling than those with lower quality classifications (PC and BPC1 N BPC2 N C N NS N BN, P b 0.05). In a steak type x season interaction (P = 0.03) for WBSF, C steaks during the winter had lower (P b 0.05) WBSF values than those during summer and fall. For NS steaks, winter steaks had lower (P b 0.05) WBSF values than spring steaks. For BN steaks, summer steaks had lower (P b 0.05) WBSF values than spring and winter steaks. During the spring, PC and BPC1 had lower (P b 0.05) WBSF values than NS and BN; and BPC2 had lower (P b 0.05) WBSF values than NS. For summer, PC, BN, and BPC1 had lower (P b 0.05) WBSF values than C. For fall, BPC2 had lower (P b 0.05) WBSF values than NS, BN, and C; and BPC1 had lower (P b 0.05) WBSF values than C steaks. For winter, PC, BPC1, BPC2, and C steaks had lower WBSF values than BN steaks. Percentages of cooking loss were lower
Objectives: The impact of using corn or soybean co-product in high or low corn grain finishing diets of feedlot heifers was evaluated using forty-four purebred Limousin heifers. Materials and methods: Heifers were randomly assigned to one of four dietary treatments (11 per treatment) that included: 65% corn grain diet with 20% modified distillers grains with solubles (HI + MDGS); 65% corn grain diet with a combination of 15.2 % soy glycerin and soybean hulls (HI + SOY); 25% corn grain diet with 60% MDGS (LO + MDGS); or 25% corn grain diet with 40% MDGS and 15.2% SOY (LO + MDGS + SOY). All heifers received melengestrol acetate and Rumensin. Experimental unit was individual heifer, as all animals were fed individually using a Calan gate system. Heifers were fed finishing diets for 129 d and were humanely harvested at a commercial facility. Hot carcass weight (HCW); 12th rib back fat (BF); rib eye area (REA); percent kidney, pelvic, and heart fat (KPH); and marbling score were collected 48 h postmortem by trained plant personnel. Strip loins (IMPS #180) were collected and fabricated into 2.54 cm steaks for evaluation of drip loss, Warner– Bratzler shear force, retail shelf life evaluation (subjective and objective), and sensory evaluation. Shoulder clods (IMPS #114) were collected and ground twice (0.375 cm plate) to create ground beef and bologna, both of which were evaluated for retail shelf life (subjective and objective). Results: There was no treatment effect for HCW (P = 0.37), BF (P = 0.10), REA (P = 0.63), KPH (P = 0.67), or marbling score (P = 0.18). Drip loss did not differ among treatments (P = 0.85). Warner–Bratzler shear force values of steaks from HI + SOY were lower (3.17 kg) than LO + MDGS + SOY (3.79 kg; P = 0.02). Treatment did not affect subjective scores for lean color (P = 0.06), surface discoloration (P = 0.19), and overall appearance (P = 0.52) or objective scores for L* (P = 0.32), a* (P = 0.41), and b* (P = 0.25) of steaks. Treatment did not affect overall liking (P = 0.59), flavor liking (P = 0.78), texture liking (P = 0.38), juiciness (P = 0.56), or off flavor (P = 0.89) of steaks. Subjective toughness ratings of steaks from HI + MDGS were higher than LO + MDGS (10.54 and 9.11 respectively; P = 0.02). L* values for 25% corn diets were higher than 65% corn diets (P b 0.01) in ground beef. Treatment did affect surface discoloration (P b 0.01) in ground beef, with HI + SOY having the highest subjective value (6.21). Treatment affected surface discoloration (P = 0.01) in ground beef, with HI + SOY having the highest mean subjective value (6.21). Treatment did have an effect on overall appearance (P = b.01) in ground beef, with HI + SOY having the highest mean subjective value (4.20). Treatment had no effect on a* (P = 0.62) or b* (P = 0.43) in ground beef. Treatment did not affect lean color (P = 1.00) or overall appearance (P = 1.00) subjective mean values or a* (P = 0.89) or b* (P = 0.82) in bologna.