Lean Color Research Articles

Evaluation of Pearl Millet With and Without Soybean Hull Supplementation for Forage-Finished Beef Production Systems

ObjectivesThe objective of this research was to evaluate pearl millet, a warm-season annual grass, with and without soybean hull supplementation for forage-finished beef production systems in the Southeast.Materials and MethodsEach year, 32 Angus-crossbred steers (339 ± 40 kg) were randomly assigned to one of four finishing treatments. Treatments were arranged in a 2 × 2 factorial and included two varieties of pearl millet, ‘Tifleaf 3’ (PM) and ‘Exceed’ brown mid-rib (BMR), and two levels of soybean hull supplementation, 0 and 0.75% of body weight d–1. Steers were on treatments for 90 and 84 d during the summers of 2017 and 2018, respectively, at the University of Georgia Department of Animal and Dairy Science Beef Research Unit located near Eatonton, GA. Shrunk weights were taken at initiation and termination of the finishing period and average daily gains (ADG) were calculated. At the end of the finishing period, steers were harvested under USDA inspection and carcass data was collected 24 h postmortem from the right side of each carcass. Striploins were then removed from the right side, vacuum packed, and allowed to age for 21 d prior to fabrication. Striploins were fabricated into 2.54-cm steaks and allocated to meats proximate (n = 1), 0 through 7 d of simulated shelf life (n = 8), trained sensory panel (n = 2), and instrumental tenderness analyses (n = 2). All data were analyzed using PROC GLIMMIX in SAS v. 9.4.ResultsSupplementation increased ADG over forage alone (P < 0.01) however, hot carcass weights were increased by supplementation in the PM steers only (P < 0.05). No treatment differences were observed for marbling score (P = 0.61), overall maturity (P = 0.49), 12th rib fat thickness (P = 0.21), ribeye area (P = 0.1668), and subjective fat color (P = 0.93). Objective carcass lean color values for L* and subjective lean color scores were different (P < 0.05). Treatment effects were also observed for carcass lean maturity scores (P < 0.05). No treatment differences were observed for meats proximate analysis (P > 0.05), instrumental tenderness as measured by Warner-Bratzler shear force (P = 0.94), initial and sustained tenderness (P = 0.66 and P = 0.29, respectively), beef and off-flavor intensities (P = 0.83 and P = 0.36, respectively), or juiciness (P = 0.54) as measured by a trained sensory panel. No treatment differences (P > 0.05) were observed for lipid oxidation or color change (Delta E) within any day of simulated shelf life. Calculated values for hue, chroma, and redness were unaffected (P > 0.05) by treatment within day of simulated shelf life.ConclusionResults indicate pearl millet is a viable forage option for forage-finished beef systems and soybean hull supplementation improves animal performance over forage alone with minimal impacts on carcass characteristics, meat quality, and shelf life.

Impacts of Various Dry-Aging Methods on Meat Quality and Palatability Attributes of Beef Loins from Cull Cow

ObjectivesBeef from cull cows has been traditionally perceived as low-quality/value meat due to its inferior flavor and tenderness. Given the negative consumer perception of highly processed fresh meat, there is a need to develop a natural post-harvest aging system to improve eating quality attributes of beef products, particularly from cull cows. Dry aging has been practiced for decades as a traditional and natural butchery process, which is also known to improve palatability characteristics. Thus, the main objective of this study was to evaluate the impact of different dry-aging methods on meat quality, microbiological properties and palatability attributes of loins from cull cow beef.Materials and MethodsPaired beef loins from 13 carcasses (Holstein, 30+ mo) were obtained at 5d postmortem, divided into 4 equal length sections and randomly assigned to four aging methods: wet-aging (WA), dry-aging (DA), dry-aging in water permeable bag (DWA) and UV-light dry-aging (UDA; 2 treatment/day, 5 J/s/treatment). Sections were aged for 28d at 2°C, 65% RH and 0.8 m/s air flow. After aging, dry-aged sections (DA, DWA and UDA) were trimmed of dehydrated surface, and trim loss and total saleable yield were recorded. The pH, proximate composition, shear force, water-holding capacity, initial color (instrumental and trained panelist), lipid oxidation (2-thiobabituric acid reactive substances, TBARS), microbial properties (aerobic plate count (APC), lactic acid bacteria (LAB), and yeast and mold (YM) counts) and trained sensory evaluation (11 panelists) were determined. Experimental design was a balanced complete block design. All data were analyzed using PROC MIXED procedure of SAS, and least squares means for all traits were separated (P < 0.05).ResultsDA and UDA had a substantial moisture loss during the aging process, accompanied with higher trim loss compared to other methods (P < 0.05). This resulted in DA having the lowest yield followed by UDA, DWA and WA with the highest saleable yield (P < 0.05). No significant differences were observed on cook loss, WBSF and TBARS between the treatments. DWA had the lowest pH out of all treatments (P < 0.05). UDA had the lowest moisture content and highest drip loss (P < 0.05). Color measurement showed that both DA and WA had significantly higher L* and lower b* values compared to UDA and DWA (P < 0.05). However, a* and lean surface color were not significantly different between the treatments (P > 0.05). For the trim, UDA had the lowest microbial growth among all treatments (P < 0.05). For the lean, UDA had the lowest count for LAB (P < 0.05), WA had the lowest in YM (P < 0.05) and no difference was found for APC between treatments (P > 0.05). Trained sensory panelist found that UDA and WA had higher fat and sour flavor (P < 0.05), and a trend (P = 0.07) of higher oxidized flavor when compared to DWA and DA.ConclusionThe results showed that dry-aging would result in no adverse impact on shear force, cooking loss, initial color and lipid oxidation of mature beef loins. Further, sour and oxidized flavor was lower in dry-aged beef, indicating its potential as value adding process. UV light application minimized microbial growth during dry-aging process, although more analyses are needed to understand its full impact on dry-aged meat quality. Further studies on determining the consumer acceptability as well as flavor-related compound analyses are currently under investigation.

Modified Atmospheric Packaging and Antioxidant Enhancement Improves Redness of Atypical Dark-Cutting Beef

ObjectivesDark-cutting carcasses occur when muscle pH does not decrease sufficiently during rigor mortis because of antemortem glycogen depletion. Typical dark-cutting beef have a pH > 6.0, however, atypical dark-cutting (ADC) beef have a pH around 5.7- 5.9 but have a darker lean color similar to dark-cutting beef. Previous studies noted that greater muscle pH in dark-cutting beef increase oxygen consumption and decrease myoglobin oxygenation. However, limited research has determined the biochemical basis of ADC. Therefore, the objectives of this study were to characterize the biochemical basis of ADC beef carcasses and to utilize modified atmosphere packaging (MAP) and rosemary enhancement to improve appearance during retail display.Materials and MethodsStrip loins from ADC and USDA Low Choice (C) carcasses were selected from a commercial beef processing plant and transported to the Food and Agricultural Products Center in Stillwater, OK. Control (C) and ADC steaks (prior to enhancement and packaging) were utilized to measure pH, color, oxygen consumption, and proximate compositions. Loin sections were cut into halves and randomly assigned to combinations of packaging types and enhancement treatment. Packaging included high-oxygen MAP (HiOx-MAP; 80% oxygen and 20% carbon dioxide), carbon monoxide MAP (CO-MAP; 0.4% CO, 69.6% N, and 30% CO2), and PVC. Enhancement includes 0.1% rosemary oleoresin pumped to 10% of loin green weights. Following enhancement and packaging, steaks were displayed under retail conditions for 6 d to measure color changes using a HunterLab spectrophotometer. The data were analyzed using the Mixed Procedure of SAS, and the experiment was replicated 13 times (n = 13).ResultsThere were no differences for initial pH or proximate compositions (P < 0.05) between C and ADC. However, ADC had lower initial lightness (L* values), redness (a* values), and red intensity (chroma) compared with C. Further, ADC had greater (P < 0.05) oxygen consumption than C. There was a significant packaging × enhancement × display time interaction resulted for L*, a*, and chroma. CO-MAP and HiOx-MAP in combination with rosemary enhancement improved (P < 0.05) redness of ADC by 61.7% and 42.3%, respectively, compared with ADC in PVC packaging. Similarly, MAP and enhancement improved lightness (L* values) and chroma compared with ADC in PVC. By Day 6 of display, enhanced ADC steaks packaged in both HiOx-MAP and CO-MAP had similar color parameters to control choice steaks; however, non-enhanced ADC steaks had significantly lower a* (P < 0.0001) and chroma (P < 0.01) values when packaged in HiOx-MAP when compared to both C and enhanced ADC.ConclusionThe results suggest that ADC beef has greater oxygen consumption than C steaks even at similar muscle pH. Use of modified atmospheric packaging in combination with enhancement has the potential to improve surface color of ADC beef.

Does Treating Beef Subprimals with UV-Light Reduce Pathogens and Impact Quality?

ObjectivesTo evaluate reduction of pathogens and impact on quality parameters of beef strip loins treated with pulsed-UV light.Materials and MethodsInoculum was prepared as a cocktail of three non-pathogenic, rifampicin-resistant E. coli Biotype I surrogates. Strip loins were halved, inoculated, individually vacuum packaged, and assigned to one of three pulsed-light UV treatments: (1) light height 5 cm, belt speed 15 Hz; (2) light height 28 cm, belt speed 15 Hz; and (3) light height 28 cm, belt speed 25 Hz. Microbiological samples were obtained and enumerated pre- and post-treatment (n = 90; 3 UV treatments × 5 strip loin halves per treatment × 2 sampling times (pre/post treatment) × 3 replications).To evaluate quality parameters, a control group was added to the three UV treatments. Uninoculated strip loin halves (n = 48) were fabricated, packaged, and assigned (n = 12 strip loins halves per treatment) to one of the four treatment groups. Within each group, n = 3 strip loin halves were assigned a storage time (0, 7, 14, or 21 d). After treatment, three steaks from each strip loin half (approximately 2.54-cm thick; n = 192 total steaks) were cut and individually packaged for analyses: (1) trained aroma and color panel, (2) steak surface pH, purge pH, purge quantification, and objective color, and (3) aerobic plate counts.Data were analyzed using JMP Pro (SAS Institute Inc., Cary, NC). The fit model function was used for analysis of variance, and least squares means comparisons were conducted when appropriate using Student’s t test with an α-level 0.05.ResultsNo differences were seen (P > 0.05) in reductions of E. coli surrogates among the three UV treatments, with all reductions less than 1-log. No differences (P > 0.05) in aroma scores among treatment groups were noted, although differences in aroma attribute scores occurred between aging times. Panelists scored samples highest (P < 0.001) for bloody/serumy on d 0 than any other aging time. Conversely, sour dairy and spoiled intensified over time with d 21 samples receiving the highest scores (P < 0.001). Although trained panelists’ responses for lean color score did not differ (P = 0.277) among UV treatments, scores for percent discoloration did (P = 0.014). Notably, percent discoloration scores for d 0 were statistically higher than other aging times, meaning that discoloration diminished as aging continued. No statistical differences were identified for L*, a*, or b* values across UV treatments. Between aging times, differences were seen (P < 0.001) for a* and b* values, with d 0 having the lowest values for both. For purge and pH, the surface pH of steaks was higher on Days 0 and 7 and began to decrease, showing statistical similarities on Days 14 and 21. The amount of purge (g) steadily increased as steaks aged. APC counts were not found to differ due to UV treatment but generally tended to increase as storage times lengthened.ConclusionPulsed-UV light on chilled subprimals resulted in low microbial reductions, however, this technology could be beneficial if used in addition to other antimicrobial interventions. Initial discoloration was identified but improved as steaks aged. While APCs tended to increase over the course of storage, as did purge, no differences due to UV treatments were seen. Further research is warranted to determine if different treatment parameters would result in greater microbial reductions.

Heat Mitigation Strategies for Finishing Beef Cattle During the Summer in the Southeastern United States Reduces Heat Load and Improves Weight Gain, but does not Influence Meat Quality

ObjectivesThe objective of this research was to determine the effect of heat mitigation strategies on meat quality when finishing cattle under heat stress conditions.Materials and MethodsForty-five Angus crossbred steers (446 ± 23 kg) were blocked by weight and randomly assigned to 1 of 3 finishing environments: shaded with fan (CWF), shaded without fan (CNF), or outside no shade (OUT). For 92 d steers were individually fed a corn-based total mixed ration and were weighed every 3 wk. Environmental monitors (Kestrel Instruments) were used to quantify heat load index (HLI) and accumulated heat load units (AHLU). When the first treatment group averaged 613 kg all steers were harvested. Carcass quality and yield data were collected 24 h postmortem. Strip loins were removed from the right side of each carcass at 24 h postmortem, vacuum packaged, and aged (2 ± 1°C) for 5 d. Strip loins were then fabricated into 2.54-cm steaks anterior to posterior. The first steak was designated for proximate analysis, followed by two steaks for slice shear force (14 and 21 d aging), two steaks for other analyses, and the remaining 7 steaks were randomly assigned to shelf life (SL) for 6 d following 28 d of wet aging. Steaks were vacuum packaged and held (2 ± 1°C) for their respective days of aging. After 28 d, shelf life steaks were opened, placed in Styrofoam trays with PVC overwrap, and placed in retail display cases (1 ± 2°C). Steaks were frozen (–20°C) once they reached their assigned day of wet aging or simulated shelf life. Objective color L* (lightness), a* (redness), b* (yellowness), and isobestic wavelengths were recorded daily (± 2 h). Hue, chroma, DE, and deoxymyoglobin (%Dmb), oxymyoglobin (%Omb), and metmyoglobin (%Mmb) were calculated. Data were analyzed using a mixed model (JMP v.13; SAS) and means were separated using LSmeans at a = 0.05.ResultsEnvironmental monitors showed that CWF and CNF had lower HLI and AHLU (P < 0.01) than OUT. Final weights were greater for CWF than OUT (P = 0.02) while CNF was similar (P ≥ 0.17) to both. Similar results were observed for hot carcass weights where CWF > OUT (P = 0.03), and CNF was similar to both (P ≥ 0.23). Treatment differences were not observed for USDA yield grade (P = 0.38), dressing percent (P = 0.93), kidney pelvic heart fat (P = 0.89), ribeye area (P = 0.47), backfat thickness (P = 0.49), marbling score (P = 0.71), overall maturity (P = 0.92), or subjective lean color (P = 0.16). No differences in fat color scores were observed between CNF and OUT (P = 0.95) while CWF were whiter (P ≤ 0.04) than both. Protein analysis showed CWF had more protein than OUT (P = 0.01) while CNF was similar to both (P ≥ 0.90). No differences were observed for lipid content (P = 0.99), ash (P = 0.39), or moisture (P = 0.92). Treatment nor day of aging effected slice shear force (P = 0.45 and P = 0.53, respectively). While treatment differences were not observed for a*, b*, hue, chroma and DE (P = 0.51, P = 0.65, P = 0.18 P = 0.57, and P = 0.57, respectively). Treatment values for L* were lighter for CNF than CWF (P = 0.04), while OUT was similar to both (P ≥ 0.14). There were no differences for %Dmb, %Omb, and %Mmb (P = 0.24, P = 0.32, and P = 0.39, respectively) among the treatments.ConclusionResults indicate that heat stress mitigation is a viable method to improve weight, however, does not impact the quality of the meat.

35 Applying GGP-F250 genotypes to elucidate the biochemical basis for animal variation in meat quality attributes

Abstract Understanding the biological factors regulating animal variation in meat quality traits continues to challenge meat scientists. Meat scientists have studied the impacts of numerous intrinsic and extrinsic variables on meat quality traits. Often, component traits, known to directly contribute to the trait of interest, have been utilized to determine the mechanisms by which these impacts are made. However, only a limited amount of the variation in these traits is explained by component traits, indicating that a significant knowledge gap exists. The rise of genotyping assays for functional alleles provides an opportunity to further understanding of the biological basis of meat quality traits. For example, lean color is the primary factor utilized by consumers in making purchasing decisions. Cuts from some carcasses discolor rapidly and must be discounted or discarded. Component traits (reducing ability and oxygen consumption) generally explains a total 30 to 40% of the variation in lean color stability. A genome-wide association study (GWAS) was conducted using GGP-F250 genotypes from 2,476 steers representing crosses of 18 beef breeds that had been phenotyped for lean color change during simulated retail display. The GWAS identified 417 single nucleotide polymorphisms (SNP) explaining the heritable variation (0.45). Identified genes included genes coding for reductases and cytochromes as well as mitochondrial genes, which are consistent with conventional wisdom regarding lean color stability. However, other genes identified are related to muscle contraction, action potential mediation, calcium binding, actin binding, stress response, and apotosis. In addition, gene ontology analysis indicates 128 genes contributing to metabolic processes, with 74 being associated with nucleobase containing compound metabolic processes. Thus, these results suggest novel mechanisms, which have not been previously studied in detail in relation to lean color stability. This approach provides a means to increase understanding of the biological regulation of meat quality traits.

77 Improving lean muscle color of atypical dark- cutting beef by antioxidant-enhancement and modified atmospheric packaging

Abstract Any deviation from the bright-red color of beef leads to discounted price or consumer rejection. Atypical dark-cutting beef represents darker color of lean around a pH 5.6 – 5.8. However, limited studies have determined the postharvest practices to improve the lean color of atypical dark-cutting beef. Therefore, the objective was to evaluate the effects of rosemary-enhancement and modified atmospheric packaging on atypical dark-cutting beef. Atypical dark-cutting beef strip loins (n = 13, pH=5.70 ± 0.09; ADC) and USDA Choice beef strip loins (n = 6, pH=5.57 ± 0.1; CH) were selected within 72 h of harvest. Atypical dark-cutting strip loins were divided into 2 sections, and randomly assigned to one of the following enhancement treatments: control non-enhanced (ADC), or a 1.1% rosemary-enhanced treatment (ADCE). After enhancement, 2.54 cm steaks were cut from CH, ADC, and ADCE strip loins and assigned to 1 of 3 packaging treatments: polyvinyl chloride overwrap (PVC), carbon monoxide modified atmosphere packaging (CO-MAP; 0.4% CO, 69.6% N, and 30% CO2), and high-oxygen modified atmospheric packaging (HiOx-MAP; 80% O2 and 20% CO2). A HunterLab MiniScan was used to determine color during the 6 d simulated retail display. Visual color measurement for muscle darkening (MD), muscle color (MC), and surface discoloration (SD) were recorded on d 2, 4, and 6 of retail display. There was a significant enhancement x packaging interaction for instrumental and visual color measurements. For all packaging types, ADCE steaks possessed greater L* values than DC steaks. In addition, ADCE steaks packaged in HiOx-MAP or CO-MAP had brighter-red color than ADC steaks. Furthermore, ADCE and C steaks had less muscle darkening compared with ADC steaks for MD and MC attributes. The results suggest that enhancement and modified atmospheric packaging have the potential to improve the surface color of atypical dark-cutting beef.

The Effect of Modified Atmospheric Packaging on Beef Color Sensory Characteristics of Different Muscle pH Categories

ObjectivesAny deviation from the bright-red color of beef can lead to discounted price or consumer rejection. Fresh beef lean color is influenced by pH. Various packaging techniques have been developed to enhance the lean color of beef steaks. Therefore, the objective of the current study was to evaluate the effects of modified atmospheric packaging on three different beef muscle pH categories.Materials and MethodsThe three categories evaluated for this study were: Normal (pH = 5.57 ± 0.1; N-pH), Moderately high (pH = 5.70 ± 0.09; M-pH), and High (pH = 6.39 ± 0.03; H-pH). The pH was taken on the carcass, at the 12th and 13th rib interface within 72 h of harvest at a commercial beef processing plant. Strip loins were fabricated from each carcass (n = 12) and sent to Oklahoma State University for further analysis. Strip loins were then cut into 2.54 cm steaks and randomly assigned to 1 of 3 packaging treatments: polyvinyl chloride overwrap (PVC), carbon monoxide modified atmosphere packaging (CO-MAP; 0.4% CO, 69.6% N, and 30% CO2) and high-oxygen modified atmospheric packaging (HiOx-MAP; 80% O2, and 20% CO2). Visual color measurements for muscle color (MC; (1 = extremely bright cherry-red and 7 = extremely dark red), and surface discoloration (SD; 1 = no discoloration [0%] and 7 = extensive discoloration [81–100%]) were recorded on d 2, 4, and 6 of retail display by a trained panel. Data were analyzed using the Mixed Procedure of SAS.ResultsFor all pH treatments, PVC packaging possessed the darkest muscle color (P < 0.05) score compared to CO- and HiOx-MAP. When comparing N-pH, M-pH, and H-pH values, CO-MAP had approximately a 27.3%, 22.2%, and 25.3% improvement in muscle color, indicating a brighter lean color compared to PVC. Additionally, HiOx-MAP had approximately a 10.9%, 17.4%, and 16.5% improvement in muscle color score for N-pH, M-pH, and H-pH, respectively. When packaging steaks in either CO- or HiOx-MAP there was no significant difference (P > 0.05) between d 4 and 6 of retail display for muscle color. However, there was a significant (P < 0.05) darkening in muscle color for steaks packaged in PVC from d 4 to 6 of retail display. By the fourth d of retail, N-pH steaks packaged in PVC had 38.3% and 39.0% greater (P < 0.05) surface discoloration than CO- and HiOx-MAP, respectively.ConclusionThese results suggest that packaging steaks of different pH categories in CO- or HiOx-MAP can improve the surface color compared to PVC packaging.

Photohydroionization Reduces Shiga Toxin-Producing Escherichia coli and Salmonella on Fresh Beef with Minimal Effects on Meat Quality

The photohydroionization (PHI) technology utilizes a combination of UV light and low-level oxidizers to produce antimicrobial action, and thus, is a potential intervention to control pathogen contamination on surface of fresh beef. The objectives of the study were 1) to evaluate the effect of PHI on reduction of selected Escherichia coli (E. coli) O157:H7, non-O157 Shiga toxin-producing E. coli (STEC; O26, O45, O103, O111, O121, O145), antimicrobial resistant (AMR) and non-AMR Salmonella strains inoculated on beef flanks, and 2) to evaluate the effect of PHI treatment on the lean color and lipid oxidation of beef during refrigerated storage. Inoculated beef flanks were exposed to PHI treatment for 0 (control), 15, 30, or 60 s at 4°C. Exposure to PHI for 15 s reduced (P ≤ 0.05) pathogens on the surface of fresh beef ranging from 0.3 to 0.9 log CFU/cm2. Increasing the exposure time to 60 s did not improve (P &gt; 0.05) reductions over 15 s for the majority of the selected pathogens, but yielded pathogen reductions ranging from 0.5 to 1.1 log CFU/cm2. Over all storage times when beef samples were exposed to PHI for 75 s, no difference (P &gt; 0.05) was detected on lean a* value (24.67 versus 24.95), of treated and control fresh beef tissues, respectively. The highest TBARS values after storage for 14 d at 4°C was 0.33 mg MDA/kg of meat indicating that no oxidative rancidity occurred for treated beef samples. The PHI technology with 15 to 75 s exposure time was effective in controlling STEC and Salmonella contaminated on surface of fresh beef without causing adverse effects on fresh beef quality while reducing water and energy use. Further study of PHI treatment parameters under commercial plant conditions and ultimate validation of those parameters will be necessary for commercial implementation.

Impacts of Chilling Duration on Marbling Score, Shrinkage, and Lean Color in Beef Carcasses

Impacts of Chilling Duration on Marbling Score, Shrinkage, and Lean Color in Beef Carcasses

Evaluating Ground Beef Formulated with Different Fat Sources

Objectives were to evaluate effects of fat source and formulated fat percentage on fatty acid composition, lean color stability, lipid oxidation, and aerobic microbial load during simulated retail display of ground beef patties. In Experiment 1 beef carcasses (n = 30) were chilled for 2 d and then fabricated. M. semimembranosus muscles were removed along with 2 fat sources (kidney and pelvic = KP and subcutaneous = S from the same carcass) and ground to achieve 75 and 95% lean. Fatty acid profile and thiobarbituric acid reactive substances (TBARS) were determined over a 7 d simulated retail display period. Saturated fat differed (P = 0.0004) by fat source, with KP having a higher percentage than S. Thiobarbituric acid reactive substances were higher for (P &lt; 0.05) for patties made with S compared to KP. In Experiment 2 beef carcasses (n = 20), were fabricated and blended into ground beef as described in Experiment 1. After designated display time patties were removed and instrumental color measurement, myoglobin concentration, TBARS, and aerobic plate counts (APC) were collected. Oxymyoglobin (OMb) percentage decreased (P &lt; 0.0001) by storage day and had source x formulated fat percentage interaction (P = 0.011). Inversely, storage day increased metmyoglobin (MMb) percentage (P &lt; 0.0001) where d 1 &lt; d 3 &lt; d 5 &lt; d 7, respectively. Changes in myoglobin form contributed to decreased a* values (P &lt; 0.0001) over time. However, APC did not differ (P &gt; 0.05) for d, fat source, or fat percentage. Discoloration in ground beef over 7 d of retail display was more a function of muscle pigment oxidation (OMb to MMb) than aerobic microbial spoilage.

Modified Atmospheric Packaging and Antioxidant Enhancement Improves Redness of Atypical Dark-Cutting Beef

ObjectivesDark-cutting carcasses occur when muscle pH does not decrease sufficiently during rigor mortis because of antemortem glycogen depletion. Typical dark-cutting beef have a pH > 6.0, however, atypical dark-cutting (ADC) beef have a pH around 5.7- 5.9 but have a darker lean color similar to dark-cutting beef. Previous studies noted that greater muscle pH in dark-cutting beef increase oxygen consumption and decrease myoglobin oxygenation. However, limited research has determined the biochemical basis of ADC. Therefore, the objectives of this study were to characterize the biochemical basis of ADC beef carcasses and to utilize modified atmosphere packaging (MAP) and rosemary enhancement to improve appearance during retail display.Materials and MethodsStrip loins from ADC and USDA Low Choice (C) carcasses were selected from a commercial beef processing plant and transported to the Food and Agricultural Products Center in Stillwater, OK. Control (C) and ADC steaks (prior to enhancement and packaging) were utilized to measure pH, color, oxygen consumption, and proximate compositions. Loin sections were cut into halves and randomly assigned to combinations of packaging types and enhancement treatment. Packaging included high-oxygen MAP (HiOx-MAP; 80% oxygen and 20% carbon dioxide), carbon monoxide MAP (CO-MAP; 0.4% CO, 69.6% N, and 30% CO2), and PVC. Enhancement includes 0.1% rosemary oleoresin pumped to 10% of loin green weights. Following enhancement and packaging, steaks were displayed under retail conditions for 6 d to measure color changes using a HunterLab spectrophotometer. The data were analyzed using the Mixed Procedure of SAS, and the experiment was replicated 13 times (n = 13).ResultsThere were no differences for initial pH or proximate compositions (P < 0.05) between C and ADC. However, ADC had lower initial lightness (L* values), redness (a* values), and red intensity (chroma) compared with C. Further, ADC had greater (P < 0.05) oxygen consumption than C. There was a significant packaging × enhancement × display time interaction resulted for L*, a*, and chroma. CO-MAP and HiOx-MAP in combination with rosemary enhancement improved (P < 0.05) redness of ADC by 61.7% and 42.3%, respectively, compared with ADC in PVC packaging. Similarly, MAP and enhancement improved lightness (L* values) and chroma compared with ADC in PVC. By Day 6 of display, enhanced ADC steaks packaged in both HiOx-MAP and CO-MAP had similar color parameters to control choice steaks; however, non-enhanced ADC steaks had significantly lower a* (P < 0.0001) and chroma (P < 0.01) values when packaged in HiOx-MAP when compared to both C and enhanced ADC.ConclusionThe results suggest that ADC beef has greater oxygen consumption than C steaks even at similar muscle pH. Use of modified atmospheric packaging in combination with enhancement has the potential to improve surface color of ADC beef.

Effects of feeding endophyte-infected tall fescue seeds to stocker Angus steers on retail quality attributes of beef strip steaks

The objective of this study was to determine the effects of feeding endophyte-infected tall fescue seeds to Angus steers during the stocker phase on the quality attributes of beef strip steaks during retail display. Endophyte-infected tall fescue seeds had no effect on steak surface lean color, myoglobin forms, proximate composition, thiobarbituric acid reactive substances, aerobic plate count, pH, activity of superoxide dismutase and metmyoglobin reductase, shear force, and sensory attributes (P ≥ 0.087). However, lightness, redness, oxymyoglobin percentage, and MRA decreased from 45.01, 32.60, 67.61%, and 9.54 μM/min/g, respectively, on d 0 to 40.11, 21.83, 48.95%, and 2.30 μM/min/g, respectively, on d 7 (P ≤ 0.001). Thiobarbituric acid reactive substances were increased by 30% by d 5 (P = 0.015) and APC was increased by 0.5 log CFU/g by d 7 (P ≤ 0.012).

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.

The Impact of Dietary Brassica Carinata Meal Inclusion on the Growth, Feed Efficiency, Carcass Merit, and Lean Quality of Finishing Pigs

ObjectivesBrassica Carinata is an oilseed crop that shows potential to produce jet fuel. The byproduct remaining after the oil is extracted is a high quality protein meal. Carinata meal supplementation has been documented to improve the growth of developing heifers. However, protein meal inclusion is a rather small percentage of the supplementation of ruminants. If Brassica carinata oil production is to become cost effective, more opportunities to utilize this high protein meal by product will need to be identified. The objective of this study was to evaluate the impact replacing soybean meal with Brassica Carinata meal (BCM) on the growth, feed efficiency, carcass merit, and lean quality of finishing pigs.Materials and MethodsOver a 42-d trial period, 30 crossbred pigs were blocked by weight and placed in 15 mixed-gender pens, each including 1 barrow and 1 gilt. Pigs were fed 1 of 3 diets: a corn soybean meal control diet (CON; n = 10), or the same diet with carinata meal replacing 25% (25; n = 10), or 50% (50; n = 10), of soybean meal. The pH of the LM and the semimembranosus muscle (SM) was measured between the 10th and 11th rib with a temperature-compensating pH meter. At 24-h postmortem, left carcass sides were fabricated into primal cuts. loins were ribbed between the 10th and 11th rib and LM area, 10th rib fat thickness, subjective marbling scores, lean color (NPPC, 2000), and lean firmness scores (NPPC, 1991) were taken at the 10th rib. Additionally, LM objective lean color (L*, a*, b*; CIE, 1978) were measured using a Minolta Chroma-Meter CR-310. LM chops were fabricated from the 10th-11th rib interface and used to record 24 h drip loss. After 7 d of storage, posterior loin section reweighed to measure purge loss. Longissimus muscle chops for Warner Bratlzer shear force analysis were cooked to internal temperatures of 71°C. LM Chops were allowed to cool then six 1.3-cm diameter cores were removed and sheared using a Warner-Bratzler shear head attached to an Instron Universal Testing machine. Longissimus muscle chops used for sensory panel evaluation were cooked using the same procedures as for Warner Bratlzer shear force. A trained sensory panel evaluated all samples for tenderness, juiciness, pork flavor intensity, connective tissue, and off-flavor and firmness.ResultsDietary treatment did not influence average daily gain (P = 0.86) or any measurement of carcass composition (P ≥ 0.17). Pigs fed 50 tended to have greater liver weights (P = 0.07) than pigs fed the CON and 25. Inclusion of BCM in the diet had no effect (P ≥ 0.15) on any measurement of intramuscular pH or fat color. Chops from CON pigs tended (P = 0.09) to have greater marbling scores than chops from pigs fed experimental diets. Loin roasts from pigs fed 25 had greater 7d loin purge loss (P = 0.04) than pigs fed the other 2 diets. Boneless loin chops from CON carcasses had more reddish pink lean color scores (P = 0.003) and had lower (darker) L* values across retail display than pigs fed experimental diets. Loin chops from pigs fed 25 or 50 had greater trained sensory tenderness scores (P < 0.01), when compared to CON.ConclusionOverall, replacing up to 50% of soybean meal with BCM is a viable option for in the diets of finishing pigs. However, more research is needed to determine BCM’s impact on lean color, water holding, and tenderness.

The Impact of Dietary Brassica Carinata Meal Inclusion on the Growth, Feed Efficiency, Carcass Merit, and Lean Quality of Finishing Pigs

ObjectivesBrassica Carinata is an oilseed crop that shows potential to produce jet fuel. The byproduct remaining after the oil is extracted is a high quality protein meal. Carinata meal supplementation has been documented to improve the growth of developing heifers. However, protein meal inclusion is a rather small percentage of the supplementation of ruminants. If Brassica carinata oil production is to become cost effective, more opportunities to utilize this high protein meal by product will need to be identified. The objective of this study was to evaluate the impact replacing soybean meal with Brassica Carinata meal (BCM) on the growth, feed efficiency, carcass merit, and lean quality of finishing pigs.Materials and MethodsOver a 42-d trial period, 30 crossbred pigs were blocked by weight and placed in 15 mixed-gender pens, each including 1 barrow and 1 gilt. Pigs were fed 1 of 3 diets: a corn soybean meal control diet (CON; n = 10), or the same diet with carinata meal replacing 25% (25; n = 10), or 50% (50; n = 10), of soybean meal. The pH of the LM and the semimembranosus muscle (SM) was measured between the 10th and 11th rib with a temperature-compensating pH meter. At 24-h postmortem, left carcass sides were fabricated into primal cuts. loins were ribbed between the 10th and 11th rib and LM area, 10th rib fat thickness, subjective marbling scores, lean color (NPPC, 2000), and lean firmness scores (NPPC, 1991) were taken at the 10th rib. Additionally, LM objective lean color (L*, a*, b*; CIE, 1978) were measured using a Minolta Chroma-Meter CR-310. LM chops were fabricated from the 10th-11th rib interface and used to record 24 h drip loss. After 7 d of storage, posterior loin section reweighed to measure purge loss. Longissimus muscle chops for Warner Bratlzer shear force analysis were cooked to internal temperatures of 71°C. LM Chops were allowed to cool then six 1.3-cm diameter cores were removed and sheared using a Warner-Bratzler shear head attached to an Instron Universal Testing machine. Longissimus muscle chops used for sensory panel evaluation were cooked using the same procedures as for Warner Bratlzer shear force. A trained sensory panel evaluated all samples for tenderness, juiciness, pork flavor intensity, connective tissue, and off-flavor and firmness.ResultsDietary treatment did not influence average daily gain (P = 0.86) or any measurement of carcass composition (P ≥ 0.17). Pigs fed 50 tended to have greater liver weights (P = 0.07) than pigs fed the CON and 25. Inclusion of BCM in the diet had no effect (P ≥ 0.15) on any measurement of intramuscular pH or fat color. Chops from CON pigs tended (P = 0.09) to have greater marbling scores than chops from pigs fed experimental diets. Loin roasts from pigs fed 25 had greater 7d loin purge loss (P = 0.04) than pigs fed the other 2 diets. Boneless loin chops from CON carcasses had more reddish pink lean color scores (P = 0.003) and had lower (darker) L* values across retail display than pigs fed experimental diets. Loin chops from pigs fed 25 or 50 had greater trained sensory tenderness scores (P < 0.01), when compared to CON.ConclusionOverall, replacing up to 50% of soybean meal with BCM is a viable option for in the diets of finishing pigs. However, more research is needed to determine BCM’s impact on lean color, water holding, and tenderness.

Genome-Wide Association of Myoglobin Concentrations in Pork Loins

Lean color is a major focus for identifying pork loins for export markets, and myoglobin is the primary pigment driving pork color. Thus, increasing myoglobin concentration should increase redness of pork products and the number of loins acceptable for exportation. Therefore, understanding genetic variation and parameters affecting myoglobin concentration is critical for improving pork color. The objective of this study was to identify genetic markers associated with myoglobin concentration in pork loin muscle. Ultimate pH and myoglobin concentrations were measured in longissimus thoracis et lumborum samples of pigs (n = 599) from two different commercial finishing swine facilities. A Bayes-C model implemented in GenSel identified regions within 7 chromosomes that explained greater than 63% of the genetic variance in myoglobin concentration. Chromosome 7 had 1 significant region which accounted for 37% of the genetic variance, while chromosome 14 had 4 significant regions accounting for 9.8% of the genetic variance. Candidate genes in the region on chromosome 7 were involved in iron homeostasis, and genes in the significant regions on chromosome 14 were involved in calcium regulation. Genes identified in this study represent potential biomarkers that could be used to select for higher myoglobin concentrations in pork, which may improve lean meat color.

Effects of Lactic Acid Dipped Beef Trim Stored 24 or 48 H and Chub Storage Duration on Ground Beef Color in Retail Display

ObjectivesThe study evaluated objective and subjective retail display color of ground beef produced from beef trim treated with or without lactic acid dip and stored 24 or 48 h prior to chub packaging and storage for 7, 14, or 21 d.Materials and MethodsGround beef produced from trim treated (TRT) with lactic acid dip (LA) or without (CON) and stored 24 h (24TS) or 48 h (48TS) was used. Samples (n = 84; 21/TRT, TS combination) were chub vacuum packaged (4.54 kg) and stored for 7, 14, or 21 d (CS) and finely ground when storage time completed. Ground beef was placed on a polystyrene tray overwrapped with low-barrier polyvinylchloride film. Packages were displayed for 3 d (2 to 3°C) under continuous fluorescent lighting. CIE L* a* b* values were taken daily during simulated retail display to calculate hue angle (tan–1 a/b) and saturation index [(a2 + b2)1/2]. Trained panelists (n = 6) evaluated worst-point lean color daily during retail display with an 8-point verbally anchored numeric scale with 0.5 increment scores (1 = very bright red, 8 = tan to brown). Data were analyzed as a split plot design with whole plot as a 2 × 2 factorial of TS and TRT and subplot combined CS with retail day.ResultsVisual color scores and L* values differed (P < 0.0001) among CS times and retail display day, as expected. Treatment, CS and retail display day interacted (P < 0.05) for a*, saturation index, and hue angle. Hue angle and a* values indicated a loss of redness (P < 0.05) within TRT and CS as retail display increased. Initial display a* values within TRT did not differ (P > 0.05) across CS, but LA treated chubs were more red (P < 0.05) than CON regardless of CS. Chubs stored 7 or 14 d had similar (P > 0.05) hue angles and were less discolored (P < 0.05) than 21 d stored chubs regardless of TRT at 0 d of display. Hue angle and a* values did not differ (P > 0.05) between LA and CON within CS after 0 d of display. Saturation index, or vividness, for 7 d stored chubs decreased (P < 0.05) the longer packages were displayed in retail, but chubs stored 14 and 21 d had similar vividness (P > 0.05) within d 2 and 3 of display. At initial display, chubs treated with LA were more vivid (P < 0.05) than CON within CS. Lactic acid treated and CON chubs did not differ (P > 0.05) within CS at d 1 and 3 of display. Chubs stored 7 d were more vivid (P < 0.05) than 14 and 21 d stored chubs, which did not differ (P > 0.05) at d 1, 2, and 3 of display. The vividness of LA treated chubs was greater (P < 0.05) than CON for 7 d stored chubs at d 2 of display. A TS × CS retail day interaction (P < 0.05) was observed for a* and saturation index. Saturation index and a* values for TS were similar (P > 0.05) within chubs stored 7 and 21 d at retail d 1 and 2 of display, but no redness differences (P > 0.05) within CS were observed at d 3 of display. Saturation index and a* values decreased (P < 0.05) as package display time increases within TS and CS, except 48TS vividness did not differ (P > 0.05) between d 2 and 3 of display. L* and b* values indicated LA treated chubs were lighter and more yellow (P < 0.05) than CON. Hue angle indicated 48TS was less red (P < 0.05) than 24TS.ConclusionLonger trim and chub storage is detrimental, but LA combined with other factors can delay discoloration.

358 Effects of rumen protected–histidine supplementation dose on finishing beef cattle

This study examined the effect of dietary rumen-protected histidine (HIS) supplementation in cattle on growth and carcass traits/product quality. Three levels of daily HIS (Balchem Corp.) were tested (control, low dose [DL], and high dose [DH]) over a 55-d finishing period in 48 crossbred steers implanted with Revalor-XS. Cattle were randomly allocated into 8 pens of 6 steers each and fed twice daily using Calan gates. Morning feed was top-dressed with the HIS as follows: control (no HIS), 50 g/steer per day (DL), or 100 g/steer per day (DH). Individual intakes were recorded, and feed and orts were analyzed every 5 d during the feeding period. Steers were harvested, carcass data was recorded, and carcasses were fabricated at a USDA-inspected facility. One longissimus lumborum (LL) and 1 gluteus medius (GM) was acquired from each animal, aged under vacuum (21 and 14 d respectively), and cut into 2.54-cm steaks. One steak was used for retail display for which subjective (to evaluate visual color components) and objective (L*, a*, and b*) color scores were recorded. Lipid oxidation on d 0 and 9 of retail display were assessed using thiobarbituric acid reactive substances. Another steak was used to evaluate cooking loss and tenderness using Warner–Bratzler shear force. Sensory taste panels were conducted (1 panel for each muscle) to determine consumer perception of the product. Muscles were analyzed using HPLC for HIS metabolite (anserine and carnosine) and HIS content. Histidine supplementation increased ADG during d 1 to 21 (DH, P = 0.07), d 42 to 60 (DL and DH, P = 0.07), and the final 50 d (DH, P = 0.07) of feeding. Supplementation with HIS also increased the lightness (DL GM, P = 0.05), degree of yellow hue (DL and DH LL, P = 0.01), oxygenated lean color (DL GM, P = 0.004), uniformity (DH GM, P = 0.03, and DH LL, P = 0.06), and overall color stability of the product from d 3 through 9 of retail display. The percent surface discoloration (DL and DH GM, P = 0.04, and DL and DH LL, P < 0.0001), degree of browning (DL and DH GM, P = 0.002, and DL and DH LL, P < 0.0001), and discoloration (DL and DH GM, P = 0.01, and DH LL, P = 0.05) of the product was decreased. The DL GM steaks were juicier (P = 0.07), more acceptable (P = 0.05), and more satisfying (P = 0.01) than the control steaks. Seventy-seven percent of panelists would purchase the DL GM product (control, 61%, and DH, 60%). In conclusion, 55 d of rumen-protected HIS treatment positively impacts consumer perception and may optimize product quality and marketability in beef cattle.

Mexican consumers at the point of meat purchase. Beef choice

Within-consumer preference replication achieved through systematic image manipulation was used in consumer surveys in four cities across Mexico (Mexico City, n=195; Guadalajara, n=100; Hermosillo, n=132; Veracruz, n=61) to study beef preferences. Images of beef steaks controlled for lean and fat colour, fat cover and marbling were presented to consumers to determine the characteristics used in beef choice and the levels of preference of these characteristics. The most important choice criteria were fat cover (62% preferring little fat cover) and marbling (59% preferring non-marbled). Lean colour was also important with 24% and 29% choosing light and dark red beef, respectively. Fat colour was the least important of the four attributes studied (18% and 19% choosing white and yellow, respectively), but was nevertheless important given that 43% of consumers used three or four characteristics to make their choice. Imported and domestic beef in the Mexican marketplace appear to respond to the range of consumers' beef preferences at the point of purchase.