Strip Loins Research Articles

PSVII-7 Relationship of slice shear force and quality grade of strip loin steaks from Brangus steers.

PSVII-7 Relationship of slice shear force and quality grade of strip loin steaks from Brangus steers.

Consumers’ sensory analysis of beef hamburger and tartare

Received: 2018-05-07 | Accepted: 2018-05-14 | Available online: 2018-11-26 https://doi.org/10.15414/afz.2018.21.04.145-148 In the last years, consumers preferences are more likely to purchase processed-meat products instead of single meat cuts. To adapt to the new demand, beef industry needs to study consumers’ sensory perception of the newly developed products to ensure their acceptability. This study aimed to examine consumers’ perception on sensory characteristics of two commercial processed-meat products (hamburger and tartare) from three different types of meat (Holstein-Italian bull, Charolaise bull, and Charolaise heifer). Sensory consumer test was conducted on a non-trained panel of 64 participants for each product to assess color, texture, odor, tenderness, juiciness, salty taste, flavor and overall satisfaction using a 1 (very low) to 7 (very high) intensity scale. Sensory data of each product was analyzed through a linear mixed model including meat type and order of presentation as fixed effects, and participant and residual as random effects. Chemical composition was determined by standard methods in 9 samples of each product (3 samples/type of meat). For hamburgers, protein ranged from 15.9 to 17.0% and fat from 9.1 to 12.9%. For tartare, protein ranged from 20.1 to 20.3%, and for fat from 3.2 to 5.2%. For hamburger, participants perceived differences (P<0.05) in color, tenderness and juiciness between meat types, being the Charolaise bull the most appreciated (P<0.05). For tartare, panelists reported differences (P<0.05) in color, texture and tenderness, being the Charolaise heifer the most appreciated (P<0.05). Our results suggested that the type of meat used related to the fat content can modify consumers’ sensory perception of processed-meat products. Keywords : bull, heifer, meat quality, processed-meat References AOAC (2000). Official Methods of Analysis, 17th ed. Arlington: Association of Official Analytical Chemists. Bureš, D. and Bartoň, L. (2012) Growth performance, carcass traits and meat quality of bulls and heifers slaughtered at different ages. Czech J. Anim Sci., 57 (1), 34-43. Campo, M.M., Sanudo, C., Panea, B., Alberti, P., Santolaia P. (1999) Breed type and ageing time effects on sensory characteristics of beef strip loin steaks. Meat Science, 51 (4), 383-390. Chambaz, A., Scheeder, M.R., Kreuzer M., Dufey, P.A. (2003) Meat quality of Angus, Simmental, Charolais and Limousin steers compared at the same intramuscular fat content. Meat Science, 63 (4), 491-500. De Marchi, M., Berzaghi, P., Boukha, A., Mirisola, M., Galol, L. (2009) Use of near infrared spectroscopy for assessment of beef quality traits . c 6(SUPPL. 1), 421-423. Gallo, L., De Marchi, m., Bittante, G. (2014) A survey on feedlot performance of purebred and crossbred European young bulls and heifers managed under intensive conditions in Veneto, Northeast Italy. Italian Journal of Animal Science, 13 (4), 3285. Grunert, K.G. (2006) Future trends and consumer lifestyles with regard to meat consumption. Meat Science, 74, 149-160. Monsón, F., Sanudo, C. (2005) Influence of breed and ageing time on the sensory meat quality and consumer acceptability in intensively reared beef. Meat Science, 71, 471-479. DOI: https://dx.doi.org/10.1016/j.meatsci.2005.04.026 Resurreccion, A.V.A. (2004) Sensory aspects of consumer choices for meat and meat products. Meat Science, 66 (1), 11-20. DOI: https://dx.doi.org/10.1016/S0309-1740(03)00021-4 Venkata, R.B., Sivakumar AS, Jeong DW, Woo YB, Park SJ, Lee SY, Byun JY, Kim CH, Cho SH, Hwang I. (2015) Beef quality traits of heifer in comparision with steer, bull and cow at various feeding environments. Journal of Animal Science, 86 (1), 1-16. DOI: https://dx.doi.org/10.1111/asj.12266

Grilling temperature effects on tenderness, juiciness, flavor and volatile aroma compounds of aged ribeye, strip loin, and top sirloin steaks

Ribeye, top loin, and top sirloin steaks were assigned a grilling temperature setting (177°C, 205°C, or 232°C) and consumer panel, Warner-Bratzler shear force, trained sensory panel, and GC/MS – olfactory analyses were performed. No differences (P > 0.05) in consumer overall, tenderness, juiciness, appearance, and flavor liking were detected among steak type or grill temperature. Grill surface temperature had no effect (P > 0.05) on trained panel tenderness scores. Of the volatiles present during an aroma event, pyrazine compounds were most influenced by grill surface temperature. The tenderness and juiciness of steaks grilled at differing temperatures were not perceived to be different by consumers; however, grilling temperature impacted the flavor of the final product by generating more pyrazine compounds. Steaks in this study likely were too tender to have a grilling effect on tenderness, but selecting different grilling temperatures can be used to vary the amount of browning of steaks and/or to modify aroma volatile compounds.

Feeding distillers grains to cattle may affect beef tenderness early postmortem.

The objective of this study was to evaluate the effects of dietary fat source with modified distillers grains plus solubles (MDGS) on beef tenderness through examination of sarcoplasmic reticulum (SR) membrane fatty acid composition, changes in sarcoplasmic calcium concentration, Warner-Bratzler shear force (WBSF), sarcomere length, and proteolysis early postmortem. Steers (n = 256) were fed for 134 d on either corn, or a diet containing 40% full-fat MDGS, 40% de-oiled MDGS, or 38% de-oiled MDGS plus 2% corn oil. Twenty-four USDA Choice carcasses (three carcasses per pen; eight pens per treatment) were selected within each dietary treatment, and strip loins were collected and aged for 2, 9, 16, or 23 d postmortem and subject to retail display (RD) for an additional 7 d. Feeding MDGS increased (P < 0.05) concentrations of linoleic acid (18:2) and tended to increase (P = 0.06) total polyunsaturated fatty acids (PUFA) in the SR membrane. Steaks from cattle fed MDGS had greater sarcoplasmic calcium concentration than steaks from cattle fed corn at day 2 postmortem (P = 0.05). Steaks from steers fed de-oiled MDGS and de-oiled MDGS plus corn oil tended to have lower WBSF values (P = 0.08) than steaks from cattle fed corn at 2 d of aging with 0 d of RD. There were no differences among dietary treatments for sarcomere length (P = 0.92) and troponin-T degradation at 2 d postmortem (P = 0.60). Results suggest that feeding MDGS may increase early postmortem release of calcium into the sarcoplasm due to increased 18:2 and PUFA concentration in the SR membrane, which could result in increased beef tenderness early postmortem.

Evaluation of marbling and enhancement's abilities to compensate for reduced beef palatability at elevated degrees of doneness.

The objectives of this study were to evaluate the extent marbling compensates for reduced beef palatability at elevated degrees of doneness and to determine the relationship of residual moisture and fat in cooked steaks to beef palatability, specifically beef juiciness. Paired strip loins (IMPS # 180) were collected to equally represent five quality treatments [Prime, Top Choice (modest and moderate marbling), Low Choice, Select, and Select Enhanced (110% of raw weight)]. Steaks were grouped into sets of three consecutively cut steaks and randomly assigned a degree of doneness (DOD): very-rare (VR; 55 °C), rare (R; 60 °C), medium-rare (MR; 63 °C), medium (M; 71 °C), well done (WD; 77 °C), or very well done (VWD; 82 °C). Samples were subjected to consumer and trained sensory evaluation, Warner-Braztler shear force (WBSF), slice shear force (SSF), pressed juice percentage (PJP) evaluation, and raw and cooked proximate analysis. There were no (P > 0.05) quality treatment × DOD interactions for consumer sensory ratings, indicating increased DOD had the same negative impact regardless of marbling level. There was a quality treatment × DOD interaction (P < 0.05) for the percentage of steaks rated acceptable by consumers for juiciness. Increased marbling modified the point in which steaks became unacceptable for juiciness. Similarly, there was a quality treatment × DOD interaction (P < 0.05) for trained juiciness ratings. When cooked to MR and lower, Prime was rated only 8% to 18% higher (P < 0.05) than Select for trained juiciness ratings, but was rated 38% to 123% higher (P < 0.05) than Select when cooked to M and higher. Besides cooking loss, combined cooked moisture and fat percentage was more highly associated (P < 0.01) to consumer juiciness (r = 0.69) and trained initial (r = 0.84) and sustained (r = 0.85) juiciness ratings than all other objective evaluations. Using regression analyses, cooked moisture and fat percentages, alone, were poor indicators of consumer and trained juiciness ratings. However, when combined, the regression equations explained 45%, 74%, and 69% of the variation in consumer, trained initial, and trained sustained juiciness ratings, respectively. These results indicate that increased marbling levels only offer "insurance" for juiciness of steaks that are cooked to high degrees of doneness, but not for other palatability traits. Additionally, cooked residual moisture and fat percentages, when combined, are a good indicator of sensory juiciness ratings.

Distribution of Marbling Throughout the M. Longissimus Thoracis et Lumborum of Beef Carcasses Using an Instrument-Grading System

Beef Loin, Strip Loins (IMPS #180; n = 20) with marbling scores between Modest00 and Modest30 at the 12th and 13th rib interface of the M. longissimus thoracis et lumborum (LL) were collected. Each strip loin was fabricated into 6 samples taken perpendicular to the long axis of the LL from the 13th thoracic vertebra to the fifth lumbar vertebra with the cut made on the anterior side of the respective vertebra. A Computer Vision System Cold Camera measured the LL cross-section of each sample location for USDA marbling score, marbling distribution, average marbling fleck size, LL area, LL length (distance medial to lateral), and LL width (distance dorsal to ventral). In the present study, mean LL marbling score decreased (P &lt; 0.05) from the second lumbar vertebrae location to the fifth lumbar vertebrae location. Marbling size and marbling distance were the smallest (P &lt; 0.05) in samples from the 13th thoracic vertebrae location. The LL area and width was largest (P &lt; 0.05) for the samples from the most anterior location and thus decreased (P &lt; 0.05) as the samples became more posterior. Samples from the most posterior end of the strip loin were the longest (P &lt; 0.05) in length. It was observed that marbling score, distribution, and size, as well as, LL area, length, and width vary from anterior to posterior in the strip loin which can have potential marketing implications for food service distributors and retailers.

Palatability of beef chuck, loin, and round muscles from three USDA quality grades.

The objective of this study was to determine the palatability of various beef cuts from 3 USDA quality grades. Five different beef subprimals from USDA Prime, Choice, and Select (n = 10/quality grade) carcasses were utilized for the study, including: strip loins, inside rounds, bottom rounds, shoulder clods, and chuck rolls. Subprimals were fabricated into 9 retail cuts, which contained the following beef muscles: longissimus lumborum (LL); longissimus thoracis, complexus, and spinalis dorsi (LCS); infraspinatus (IF); serratus ventralis (SV); triceps brachii (TB); teres major (TM); adductor (AD); semimembranosus (SM); and biceps femoris (BF). The pH and percentage of fat, moisture, protein, and collagen was determined for each muscle on a raw basis. Additionally, cooked steak measurements included Warner-Bratzler shear force (WBSF) and slice shear force (SSF). Consumer and trained sensory panelists evaluated palatability traits of each cut and quality grade combination. A quality grade × muscle interaction was determined for trained panelists assessment of overall tenderness (P = 0.03), SSF (P = 0.02), proximate composition (P < 0.01), and pH (P < 0.01). In all objective and subjective measurements of tenderness, the LCS was the most tender (P < 0.05), while cuts from the round (BF, AD, and SM) were among the toughest and least juicy (P < 0.05). Conversely, consumers and trained sensory panelists identified the LCS, IF, and SV to be juicier (P < 0.05) than all others. The TB, TM, and LL were perceived by consumers most often as being everyday quality. The LCS was found by consumers to be the most acceptable (P < 0.05) across all attributes, with the SM being the least (P < 0.05) acceptable muscle. For each muscle, fat percentage was the greatest (P < 0.05) in Prime cuts. Slice shear force determined Prime IF, LL, and SV to be more tender (P < 0.05) than Choice and Select. No SSF differences (P > 0.05) were found among quality grades for the AD, BF, and SM. The WBSF values decreased (P < 0.05) across all muscles, as quality grade increased (Prime < Choice < Select). The results of this study indicate that muscles from the chuck may be utilized to provide consumers with a positive eating experience. Meanwhile, muscles from the round are likely to provide consumers with a lower quality eating experience.

Honduran and U.S. Consumer Assessment of Beef from Various Production Systems with or Without Marinating

Our objective was to evaluate the effects of different Honduran cattle production systems, enhancement, and country of origin on palatability of the longissimus muscle aged 21 d postmortem as determined by U.S. and Honduran consumers (n = 240/country). U.S.-sourced strip loins (n = 10/treatment) were selected: USDA Select (SE) and Top (upper 2/3) Choice (TC). Honduran-sourced strip loins (n = 10/treatment) included: 1) dual-purpose bulls, raised on native pasture (HDP), 2) F1 crossbred Brahman bulls finished on a corn-based grain diet for 180 d (HCF), and 3) purebred Brahman bulls finished on a sugarcane-based diet for 180 d (HSC). Ten additional strip loins from each Honduran treatment were selected and enhanced (E; 112% ± 3.5%) with water, salt, and tripolyphosphate, resulting in EHDP, EHCF, and EHSC. Steaks were cooked to 77°C prior to consumer evaluation of tenderness, juiciness, and flavor and overall liking, with classification of each trait as acceptable or unacceptable. Consumers indicated if they were willing to pay 0, 3, 6, or 10 USD/0.45 kg. Consumer data were analyzed using the GLIMMIX procedure of SAS as a split plot design, with treatment as the whole plot factor and country and the country × treatment interaction as the subplot factors, including panel as a random effect. The EHCF had greater (P &amp;lt; 0.05) scores for tenderness, juiciness, flavor and overall liking. No differences (P &amp;gt; 0.05) were found between TC and SE when scoring palatability traits, but more (P &amp;lt; 0.05) consumers found TC acceptable for juiciness compared to SE. Honduran consumers ranked all palatability traits greater than U.S consumers and found a greater percentage of samples acceptable for tenderness (P &amp;lt; 0.05). Enhancement of Honduran treatments had a positive effect on palatability traits, as well as the acceptability of those traits. Regardless of the differences in breeds, using high-energy diets and enhancement resulted in greater palatability scores.

Comparing Honduran and United States Consumers’ Sensory Perceptions of Honduran and U.S. Beef Loin Steaks

The objective of this study was to compare the eating quality characteristics of beef from the United States and Honduras and to assess the willingness of Honduran and U.S. consumers to pay for these products. All U.S. sourced strip loins from grain-finished cattle, aged 21 d, were selected to equally represent USDA Select (SEL; n = 6) and upper 2/3 (Top) Choice (TC; n = 6) quality grades. Additionally, strip loins (n = 6) from Honduran grass-finished (HGRASS) cattle and grain-finished (HGRAIN) cattle (n = 6) were collected from a commercial abattoir in Siguatepeque, Honduras and aged 21 d. Samples were evaluated on 8-point hedonic scales for flavor, tenderness, juiciness, and overall liking by 240 consumers in each country. Consumers indicated if each trait was acceptable, and willingness to pay for each sample was rated in U.S. dollars (or the Honduran Lempiras equivalent): $0, 3, 6, and 10 per 0.45 kg. Chemical composition and Warner-Bratzler shear force (WBSF) were also determined. The TC had greater (P &lt; 0.05) fat percentage than SEL and HGRASS, but did not differ (P &gt; 0.05) from HGRAIN. The HGRAIN had greater WBSF values than TC and SEL, which did not differ (P &gt; 0.05); however, HGRASS was similar (P &gt; 0.05) to all other treatments. The TC had greater tenderness and flavor liking scores (P &lt; 0.05) than all other treatments, followed by SEL, HGRASS, and HGRAIN, with a significant difference between each treatment. Honduran consumers assigned greater ratings for tenderness and flavor liking when compared to U.S. consumers. The lowest rated treatment in both countries was Honduran grain-finished followed by Honduran grass-finished. Consumers in Honduras were willing to pay more for samples when compared to U.S. consumers. Consumers were also willing to pay a premium for products with greater palatability, regardless of the country of origin.

Effects of USDA quality grade and cooking on water-soluble precursors of beef flavor

The objective of the current study was to determine the effects of three USDA quality grades and cooking on the water-soluble flavor precursors of beef Longissimus lumborum. Raw and cooked steaks from beef strip loins of USDA Prime (PR; n = 8), Low-Choice (LC; n = 8), and Standard (ST; n = 8) were analyzed for extractable free amino acids, reducing sugars, and other nitrogenous organic compounds (NOCs). Overall, two-way quality grade × cooking interactions were found for the contents of most water-soluble precursors (Pquality grade × cooking < 0.05), which were greater in raw LC and ST and were changed more in ST and LC steaks by cooking. The magnitude of those changes suggested that cystine, a dimer of cysteine, glucose, and glucose 6-phosphate might play more important roles in beef flavor development than previously thought.

Muscle-Specific Mitochondrial Functionality and Its Influence on Fresh Beef Color Stability.

During retail display tenderloin steaks packaged in PVC overwrap discolor quicker than strip loin steaks. This research determines the basis for muscle-specific differences in color stability. The results indicate that mitochondria present in tenderloin lose its functionality faster than strip loin mitochondria. Developing strategies to minimize muscle-specific differences in mitochondrial changes can increase color stability and value of fresh beef.

Effects of dietary fat source on beef strip loin steak display life

The effects of feeding different dietary fat sources with modified distillers grains plus solubles (MDGS) on beef display life were evaluated. Steers (n = 256) were fed for 134 d on either a corn, 40% full-fat MDGS, 40% de-oiled MDGS, or 38% de-oiled MDGS plus 2% corn oil diet. Twenty-four United States Department of Agriculture Choice carcasses (3 head/pen) were randomly selected within each dietary treatment and strip loins were collected and aged for 2, 9, 16, or 23 d. Steaks from each aging period were placed under retail display (RD) conditions for 0, 4, and 7 d. Stearic acid was predominant (C18:0; P = 0.03) in beef from the de-oiled MDGS plus oil treatment in comparison with all other dietary treatments. Feeding MDGS increased linoleic acid (C18:2; P < 0.01) and polyunsaturated fatty acids (PUFA; P = 0.01) in comparison to the corn diet. The de-oiled MDGS plus oil group had greater C18:3 content (P = 0.03) when compared to corn, but no differences were observed between all other diets. There were no differences among dietary treatments for L* (P = 0.74) and b* (P = 0.25) values. The de-oiled MDGS group had lower a* values than all other treatments (P < 0.01) at day 5 of RD. The corn treatment had greater a* values (P ≤ 0.05) than de-oiled MDGS and de-oiled MDGS plus oil at day 6 and 7 of RD. Strip loin steaks from cattle fed full-fat MDGS tended to have lower a* values (P = 0.10) than steaks from cattle fed corn at day 7 of RD. Feeding de-oiled MDGS resulted in greater discoloration (P ≤ 0.05) at days 5, 6, and 7 of RD when compared to corn. Steaks from the de-oiled MDGS plus oil and full-fat MDGS groups had greater discoloration scores at day 7 of RD in comparison to corn (P ≤ 0.05). Strip loin steaks from cattle fed corn tended to have lower thiobarbituric acid reactive substance (TBARS) values (P ≤ 0.10) in comparison to de-oiled MDGS and de-oiled MDGS plus oil at day 7 of RD. Results suggest that feeding MDGS to cattle reduces color and lipid stability in addition to increasing C18:2 and PUFA content of beef. Addition of corn oil to de-oiled MDGS decreased redness and increased discoloration and lipid oxidation in comparison to corn diets.

Türkiye’nin Güney Marmara Bölgesinde Piyasaya Sunulan Holstein Irkı Erkek Sığır Karkaslarında Perakende Parça Ağırlık ve Oranlarının Belirlenmesi

The objective of this study was to determine further-processing characteristics and share of valuable cuts in Holstein carcasses marketed in South Marmara Region of Turkey. The data-set collected from a commercial slaughterhouse included observations of 311 purebred Holstein bulls. The mean values were determined 510.27±5.11 kg for pre-slaughter weight, 273.07±2.75 kg for hot carcass weight and 53.57±0.15 % for hot carcass dressing. Mean cold-carcass weight was 266.34±2.67 kg and mean carcass bone content was 19.05±0.09 %. In addition, the means for valuable cuts including rib, roast, sirloin, cutlet and strip loin were 17.17±0.19 kg, 3.35±0.05, 2.74±0.04 kg, 8.74±0.11 kg and 4.65±0.06 kg, respectively. Total yield of valuable retail cuts were 36.66±0.42 kg with the percentage of 13.74±0.06 % and the processing loss was 8.19±0.11 kg with the percentage of 3.11±0.04 %. Statistical analysis revealed that highly significant differences were observed between slaughter age groups. Moreover, significant correlations were found between pre-slaughter / carcass weights and all carcass traits analyzed. The present results may be useful for an effective evaluation of carcass characteristics in beef market of Turkey.

Improving Cull Cow Meat Quality Using Vacuum Impregnation.

Boneless strip loins from mature cows (50 to 70 months of age) were vacuum impregnated (VI) with an isotonic solution (IS) of sodium chloride. This study sought to determine the vacuum impregnation and microstructural properties of meat from cull cows. The experiments were conducted by varying the pressure, (20.3, 71.1 kPa), and time, (0.5, 2.0, 4.0 h), of impregnation. After the VI step, the meat was kept for a time, (0.0, 0.5, 2.0, 4.0 h), in the IS under atmospheric pressure. The microstructural changes, impregnation, deformation, and porosity of the meat were measured in all the treatments. Impregnation and deformation levels in terms of volume fractions of the initial sample at the end of the vacuum step and the VI processes were calculated according to the mathematical model for deformation-relaxation and hydrodynamic mechanisms. Scanning electron microscopy (SEM) was used to study the microstructure of the vacuum-impregnated meat samples. Results showed that both the vacuum and atmospheric pressures generated a positive impregnation and deformation. The highest values of impregnation (10.5%) and deformation (9.3%) were obtained at of 71.1 kPa and of 4.0 h. The sample effective porosity () exhibited a significant interaction (p < 0.01) between . The highest (14.0%) was achieved at of 20.3 kPa and of 4.0 h, whereas the most extended distension of meat fibers (98 μm) was observed at the highest levels of p1, t1, and t2. These results indicate that meat from mature cows can undergo a vacuum-wetting process successfully, with an IS of sodium chloride to improve its quality.

Comparison of meat quality, fatty acid composition and aroma volatiles of Chikso and Hanwoo beef.

ObjectiveAlthough Hanwoo has been selected as the superior commercial beef cattle breed in Korea, Chikso (Korean brindle cattle) is still recognized as a valuable breed for beef production. The aim of this study was to compare the meat quality, fatty acid composition and aroma volatiles of beef from Chikso and Hanwoo steers maintained under identical feed management, as information regarding these characteristics is still limited.MethodsA total of 19 carcasses with a quality grade of 1 were selected, and strip loin (longissimus lumborum) cuts were collected from 11 Hanwoo carcasses and 8 Chikso carcasses. Meat quality and aroma analyses were performed at day four postmortem.ResultsThough Hanwoo strip loin tended to have higher fat content (15.37%) than Chikso (12.01%), no significant differences were observed. Meat pH, water-holding capacity, cooking loss, shear force value, instrumental surface color (Commission International De L’eclairage L*, a*, b*, chroma, and hue angle) and fatty acid composition were not significantly different. Roasted Chikso beef released more intense aroma than roasted Hanwoo beef based on the total area units of identified volatiles. Among identified volatiles, the amounts of toluene, heptanal, octanal, and nonanal were higher in roasted Chikso beef than in roasted Hanwoo beef. In addition, the aroma pattern of the roasted beef from these breeds was well-discriminated by electronic nose.ConclusionNo distinct differences were found in terms of meat quality between Hanwoo and Chikso beef in this study. However, the aroma pattern and volatiles of roasted Hanwoo and Chikso beef were different according to instrumental analysis.

The physical and biochemical effects of pre-rigor high pressure processing of beef

High pressure processing (HPP) of pre-rigor longissimus thoracis (strip loin) from prime and bull animals substantially decreased the shear force and improved consumer eating attributes of the final meat product. The improved tenderness in both prime and bull meat was associated with a lower myofibrillar fragmentation index and reduced calpain 1 activity which indicated the mechanism of tenderisation was different from that which occurred in chill aged meat. Light microscopy showed disruption to the fibre packing within the muscle and electron microscopy confirmed significant disruption of the Z discs and M lines and disappearance of the A lines. Thus, HPP is associated with a reduction in the structural integrity and strength of the sarcomeres. These effects were consistent in strip loins sourced from prime and bull stock. HPP also led to the movement of glycogen phosphorylase from the sarcoplasmic fraction to the insoluble myofibrillar fraction in all animals and this was associated with a higher pH at 24 h.

Novel nitrite-embedded packaging improves surface redness of dark-cutting longissimus steaks.

The objective of this research was to determine the effects of nitrite-embedded/FreshCase packaging on lean color of dark-cutting beef. Eight dark-cutting (pH > 6.0) and eight USDA Low Choice (normal-pH; mean pH = 5.6) beef strip loins (longissimus lumborum) were selected 3 day after harvest. Each dark-cutting loin was sliced into five 2.5-cm thick steaks and randomly assigned to 1) dark-cutting steak packaged in polyvinyl chloride film (PVC) overwrap, 2) dark-cutting steak packaged in nitrite-embedded film, 3) dark-cutting steaks dipped in 0.2% rosemary solution and packaged in nitrite-embedded film, and 4) dark-cutting steak dipped in deionized water and packaged in nitrite-embedded film. The fifth dark-cutting steak was used to determine pH and proximate composition. Normal-pH choice loins were used as a control and each loin was randomly assigned to either PVC overwrap for retail display or to determine pH and proximate composition. Packages were placed in coffin-style retail display cases under continuous fluorescent lighting for 3 days. A HunterLab MiniScan XE Plus spectrophotometer was utilized to characterize steak color every 24 h. There was a significant treatment × storage time interaction (P < 0.05) for a* values and nitric oxide myoglobin formation. On days 1, 2, and 3 of the display, nitrite-embedded treatment improved (P < 0.05) redness compared to other dark-cutting steaks in PVC. A 45% increase in redness (P < 0.05) was observed for nitrite-embedded rosemary treatment over dark-cutting steak in PVC on day 3 of display. Nitric oxide myoglobin formation on day 0 was less for all dark-cutting steaks in nitrite-embedded packaging. Metmyoglobin content was greater (P < 0.05) on day 0 for dark-cutting steaks packaged in nitrite-embedded treatments than dark-cutting steaks in PVC. However, metmyoglobin level in dark-cutting steaks packaged in nitrite-embedded treatments decreased (P < 0.05) on day 1 compared with day 0. Dark-cutting steaks packaged in PVC had greater (P < 0.05) L* values on day 0 than other dark-cutting steaks in nitrite-embedded packaging. Conversely, on days 1, 2, and 3, there were no differences (P > 0.05) in L* values between dark-cutting treatments. Dark-cutting steaks in nitrite-embedded packaging had lower total plate count (P < 0.05) than dark-cutting steak packaged in PVC. The current research indicated that nitrite-embedded packaging has the potential to improve surface color of dark-cutting beef.

Lipid Oxidation of American Grain-Fed and New Zealand Grass-Fed Strip Loins Varying in Aging Time and Marbling Level

ObjectivesGrass-fed beef imported from New Zealand has been known to be lower in fat content and undergo a longer wet-aging period during transport compared to domestically produced beef. The effects of wet-aging time on oxidative metrics in highly marbled grass-fed beef are not fully known at this time. Therefore, the objective of this research was to assess the lipid stability of grass-fed strip loin steaks in comparison to grain-fed strip loin steaks from 5 different United States Department of Agriculture (USDA) quality grades, wet-aged for 7, 21, and 42 d.Materials and MethodsBeef strip loins (n = 200) representing 2 fed cattle types (n = 100/finishing type: grass-finished and grain-finished) and 5 different USDA quality grades (n = 20 per quality grade: USDA Standard, Select, Low Choice, “Top” Choice: High and Average Choice, and Prime) were acquired from beef processing facilities in New Zealand (grass-fed) and Nebraska (grain-fed). Each strip loin was equally portioned into thirds, vacuum packaged, and assigned to 1 of 3 wet aging periods (7, 21, or 42 d). After the appropriate aging period, portions (n = 600) were frozen and stored at the Gordon W. Davis Meat Science Laboratory until further fabrication. Frozen strip loin portions were cut into 2.54 cm steaks using a band saw. Prior to cutting portions into steaks, steak samples for thiobarbituric acid-reactive substances (TBARS) were taken from the anterior and posterior face steaks of each strip loin portion. The steak pieces for TBARS analysis were vacuum packaged and frozen until homogenization. Samples were thawed for 12 to 24 h, trimmed of subcutaneous fat and connective tissue, frozen in liquid nitrogen and homogenized for TBARS analysis. The amount of TBARS was determined to estimate lipid oxidation, and results were reported in mg malondialdehyde/kg sample. Statistical analyses were conducted using the procedures of SAS (Version 9.3; SAS Inst. Inc., Cary, NC). Treatment comparisons were tested for significance using PROC GLIMMIX with ɑ = 0.05.ResultsA diet by age time interaction was found for TBARS values (P < 0.05). No difference was found between grass-fed 7, 21, or 42 d treatments for TBARS (P > 0.05), indicating prolonged aging periods had no detrimental effect on grass-fed strip loins. Whereas, grain-finished strip loins aged 42 d had greater TBARS values than shorter aged product (P < 0.05). All grain-finished strip loins, regardless of age, had higher TBARS values than all grass-finished strip loins (P < 0.05). Finally, no difference was found between quality grades for TBARS (P > 0.05). The TBARS values for all samples were low, ranging from USDA Standard at 0.098 mg/kg to USDA Low Choice at 0.111mg/kg.ConclusionIn conclusion, all steaks had very low levels of lipid oxidation, due to aging in a vacuum package. Although lipid oxidation tended to increase with longer periods of wet-aging time, steaks from grass-fed cattle were less susceptible to lipid oxidation than grain-fed cattle.

Consumer Sensory Evaluation of Beef Strip Loin Steaks from 5 Quality Treatments Cooked To 6 Degrees of Doneness

ObjectivesThe objective of this study was to determine the effect of degree of doneness (DOD) on the palatability of beef strip loin steaks of varying marbling levels.Materials and MethodsPaired strip loins (IMPS # 180) were collected from 4 USDA quality grades [Prime, Top Choice (Modest and Moderate marbling), Low Choice, Select; n = 12 pairs/quality grade]. Additionally, 12 pairs of Select strip loins were collected for a salt and alkaline phosphate enhancement solution (108% of raw weight). Subprimals were aged for 21 d and fabricated into 2.54-cm thick steaks. Steaks were fabricated in groups of 3 consecutively cut steaks, with a total of 6 groups per strip loin pair. Groups were assigned to a DOD: very-rare (55°C), rare (60°C), medium-rare (63°C), medium (71°C), well-done (77°C) or very well-done (82°C). Steaks were cooked on clamshell style grills to their specified DOD. Consumers (n = 360) were fed 8 samples under red lighting and evaluated for juiciness, tenderness, flavor, and overall liking on continuous line scales. Additionally, consumers rated each trait as either acceptable or unacceptable.ResultsThere were no interactions (P > 0.05) between quality treatment and DOD for consumer ratings of all palatability traits. Select Enhanced steaks had the highest (P < 0.05) consumer ratings for all traits, followed by Prime steaks having higher (P < 0.05) ratings than Top Choice, Low Choice, and Select steaks. Select steaks had the lowest (P < 0.05) consumer ratings for all traits except tenderness, for which they were similar (P > 0.05) to Low Choice. Juiciness was similar (P > 0.05) between very-rare and rare, as well as between rare and medium-rare. Very-rare, rare, and medium-rare steaks had similar (P > 0.05) ratings for all palatability traits except juiciness. There was a quality grade by DOD interaction (P < 0.05) for the percentage of steaks rated acceptable for juiciness, tenderness, and overall liking. At very rare, rare, and medium-rare, all quality grades except Select were similar (P > 0.05) in the percentage of steaks rated acceptable for juiciness. However, as DOD increased, marbling had a greater impact, with Prime having a greater (P < 0.05) number of samples rated acceptable for juiciness than all non-enhanced samples at very well-done. Select Enhanced steaks had the greatest (P < 0.05) percentage of samples rated acceptable for tenderness at very-rare, but Prime was similar (P > 0.05) to Select Enhanced for all other DOD. Additionally, Select had the lowest (P < 0.05) percentage of steaks rated acceptable for tenderness at medium-rare and medium, but were similar (P > 0.05) to Low Choice at all other DOD. Prime and Select Enhanced steaks had similar (P > 0.05) percentages of samples rated acceptable overall for all DOD except medium and well-done, in which Select Enhanced was higher (P < 0.05). Select had a similar (P > 0.05) percentage of steaks rated acceptable as both Choice treatments at very-rare and rare, but had a lower (P < 0.05) percentage than Low Choice at medium-rare and was lower than both at medium.ConclusionThese results indicate that increased marbling level or enhancement has a positive impact on palatability ratings across all DOD. However, beef with higher marbling levels are acceptable at a higher rate at elevated DOD. With this, consumers can purchase steaks of lower quality when cooking to lower DOD, and vice versa, and still have a desirable eating experience.

Effects of Cattle Backgrounding Diets on Carcass Characteristics and Beef Quality

ObjectivesTo determine how backgrounding cattle will affect carcass characteristics and fresh beef quality. It was hypothesized that backgrounding cattle will result in an increased hot carcass weight, without impacting fresh beef quality.Materials and MethodsThe impact of utilizing a moderate energy backgrounding diet was evaluated using 95 crossbred steers (initial body weight: 352 ± 30 kg) that were randomly assigned to 1 of 15 pens. Each pen was randomly assigned 1 of 2 dietary treatments. Dietary treatments included a traditional high energy (HigE) finishing diet (n = 7) or a moderate energy (ModE) backgrounding diet (n = 8). Cattle on HigE were fed a high energy finishing diet for all 193 d; those fed ModE were fed the moderate energy diet for 63 d followed by feeding the HigE diet for the last 130 d. All steers received Revalor-XS on d 1. Two steers were randomly chosen from each pen for further evaluation. Hot carcass weight (HCW), 12th rib backfat (BF), ribeye area (REA), marbling score, USDA yield grade, and percent kidney, pelvic, and heart fat (KPH) were collected 48 h postmortem. Strip loins (IMPS #180) were retrieved and evaluated for vacuum purge loss and objective backfat color. The strip loins were fabricated into 2.54 cm steaks for drip loss, Warner-Bratzler shear force (WBSF), sensory evaluation, and subjective and objective color score evaluation. Data were analyzed using the mixed procedure of SAS (SAS Inst. Inc., Cary, NC) with treatment as a fixed effect and pen as a random effect. Pen was the experimental unit. Significance was determined at p ≤ 0.05, while trends were determined at p ≤ 0.10.ResultsThere was a tendency for HCW to be heavier for ModE cattle (P = 0.06). There was no treatment effect for BF (P = 0.43), REA (P = 0.96), Marbling (P = 0.16), YG (P = 0.76), or KPH (P = 0.22). No moisture loss attributes differed between treatments: Purge loss (P = 0.40) and drip loss (P = 0.41). Backfat a* (P = 0.43) and b* (P = 0.18) values were not statistically significant between treatments, however, L* (P = 0.06) tended to be higher for HigE cattle. Warner-Bratzler shear force values did not differ between treatments (P = 0.72). There were no treatment effects for any of the steak subjective sensory attributes evaluated: Overall liking (P = 0.80), flavor liking (P = 0.75), texture liking (P = 0.44), toughness (P = 0.31), juiciness (P = 0.65), and off-flavor (P = 0.21). Objective color score did not differ between the 2 treatments: L* (P = 0.39), a* (P = 0.55), and b* (P = 0.68). Subjective color (P = 0.11) and discoloration (P = 0.21) scores also showed no differences between treatments. Subjective sensory analysis showed that steaks from the HigE treatment tended to be more desirable (P = 0.10).ConclusionFeeding a backgrounding diet before finishing led to similar carcass characteristics with a lower reliance on concentrate feed ingredients. Backgrounded cattle also had similar fresh beef qualities but could be compromised at the retail display case with subjective desirability scores tending to be lower.