Metmyoglobin Reducing Activity Research Articles

The combined effect of vacuum-skin packaging and oxygen absorbers on the color stability and physicochemical properties of wet-aged Chikso beef

Beef discoloration during wet aging is mainly attributed to deoxymyoglobin or metmyoglobin accumulation. We applied advanced packaging methods including vacuum-skin packaging, oxygen absorbers, and their combination to maintain color stability and physicochemical attributes of Chikso beef during aging. Meat blocks from semimembranosus muscle were assigned to a 2 × 2 factorial arrangement that involved two packaging types (conventional vacuum packaging and vacuum-skin packaging) and the presence of oxygen absorbers (exclusion or inclusion) inside a package. After packaging, samples were wet-aged for 28 days. Addition of oxygen absorbers significantly increased beef color stability. Vacuum-skin packaging significantly increased metmyoglobin reducing activity and retarded lipid oxidation of beef. Moreover, their combination significantly prevented visual beef discoloration evaluated by panelists. Therefore, combination of these two packaging technologies could be effective in maintaining color stability and physicochemical attributes of Chikso beef during aging.

Change in Myoglobin Denaturation and Physiochemical Properties Among Three Degrees of Doneness and Three Beef Whole Muscles

While the factors impacting raw meat color have been extensively explored, the factors affecting cooked meat color have been largely ignored, leaving a gap in research. Establishing a baseline for the changes that accompany different degrees of doneness (DOD) could serve as the foundation for future studies to further understand what factors are impacting differences in cooked color of whole muscles. Beef strip loins (n=12) and top butts (n=12) were used to evaluate the Longissimus dorsi (LD), Biceps femoris (BF), and Gluteus medius (GM) between 3 DOD: medium rare (62.8°C), medium (71.1°C), and well-done (76.7°C). Immediately after cooking, steaks were sliced, evaluated for L*, a*, b*, frozen in liquid nitrogen, and blended into a powder for lab assays including myoglobin denaturation, metmyoglobin-reducing activity (MRA), surface hydrophobicity, proximate analysis, and lipid oxidation. An additional steak was cooked for shear force and cook loss. As expected, the a* values decreased (P<0.05) and myoglobin denaturation percentages increased (P<0.05) with increasing DOD, while muscle source did not impact (P>0.05) either. Surface hydrophobicity, which is a measure of exposed hydrophobic groups caused by denaturation, increased (P<0.05) with increasing DOD, while MRA decreased (P<0.05) with each DOD. However, the BF and GM muscles resulted in greater (P<0.05) MRA compared to the LD. There was an interaction (P<0.05) for lipid oxidation. As DOD increased past the raw state, differences inoxidation between muscles emerged. While the factors evaluated among the DOD were impacted, muscle type surprisingly affected most assays evaluated as well. This study can serve as a foundational paper to support future cooked color research to further understand what factors impact cooked color and cooked color stability of whole muscle cuts.

128 Impact of different levels of dark-cutting severity on the retail color and color stability of beef longissimus lumborum steaks

Abstract Dark-cutting beef is hallmarked by a dark red to almost purple color present within the interface of the ribeye between the 12th and 13th rib of the beef carcass. Yet, the shade or degree of darkness present within the ribeye can vary widely and have a substantial impact on the color and biochemical traits of the steaks. However, limited studies have compared color characteristics of different degrees of dark-cutting during retail display. Therefore, the objective of this study was to evaluate the impact of the visual degree of dark cutting at the time of grading on the retail color and color stability attributes of beef longissimus lumborum steaks. Beef strip loins (IMPS #180) were collected from two different Midwestern beef processors over the course of two collections. Strip loins (n = 8/treatment) were identified based on the degree of dark-cutting present within the ribeye to represent one-half dark, two-thirds dark, full dark, and a control of USDA Choice. At 48 to 60 h postmortem, loins were fabricated from the anterior end into 2.54 cm steaks and randomly assigned to retail display or d 0 lab analysis. Steaks designated for retail display were placed into Styrofoam trays and overwrapped with polyvinyl chloride film, and placed into retail display in coffin style display cases under continuous lighting for 5 d. Steaks designated for d 0 analysis were evaluated for pH, bloom, oxygen consumption, and metmyoglobin reducing activity. All color measurements were taken using a HunterLab MiniScan EZ spectrophotometer. The data were analyzed using the PROC GLIMMIX procedure of SAS at an α < 0.05. Two-thirds and full dark-cutter steaks had a greater (P < 0.05) pH than half and normal steaks on d 0. Moreover, full dark-cutter steaks had a decreased (P < 0.05) bloomed L* value and were darker in color on d 0 than normal and half steaks. Full dark-cutter steaks had a greater (P < 0.05) oxygen consumption and metmyoglobin reducing activity on d 0 than normal and half steaks. Full and two-third steaks had a decreased (P < 0.05) a* value and were less red in color on d 0 of retail display than normal and half steaks. All degrees of dark-cutters had a reduced change in redness than USDA Choice steaks. These results indicate color stability activity can be dependent on the degree of dark-cutting, with full and two-thirds dark-cutters being similar in biochemical activity.

127 Color and oxidative stability of Longissimus lumborum muscles from artificially raised ram lambs finished on a high-concentrate diet

Abstract Pre-weaning strategies, such as artificially raising on milk replacer, can impact lamb quality. Limited studies have examined the influence of artificial raising on color attributes of lamb. The aim of this study was to evaluate how artificially raising on milk replacer affects the color and oxidative stability of longissimus lumborum (LL) muscle from ram lambs finished on a high-concentrate diet. For a 60-day pre-weaning period, Polypay ram lambs were reared either conventionally with ewes (CR; n = 5) or artificially on milk replacer (MR; n = 5). After 60 days, the lambs were finished on a high concentrate diet (85:15 concentrate: forage) containing 78% cracked corn and 22% pre-mixed protein pellet as the concentrate source as well as 15% orchard grass pellet as the forage source. The lambs were fed ad libitum high-concentrate diet until the target body weight of 59 kg. The lambs were harvested, and the LL muscles from both sides of the carcasses (24 h post-mortem) were fabricated into 2.5-cm thick chops. Carcass characteristics were recorded during harvesting and fabricating. The chops were placed on polystyrene trays, overwrapped with oxygen-permeable polyvinyl chloride film, and stored at 2°C in the darkness for 0, 3, and 6 d. Instrumental color, color stability (R630/580), pH, lipid oxidation, and myoglobin reducing activity of the chops were evaluated on the storage days. A split-plot design was employed to analyze the data. Pre-weaning management was the main plot, while the storage time was considered as the sub-plot. The LL muscles from each lamb carcass were considered as the experimental unit, whereas the sub-plot experimental units were the chops allocated for 0, 3, or 6 d storage. The data were analyzed using the PROC GLIMMIX. The least square means were separated utilizing the PDIFF option and adjusted with the Tukey-Kramer method. The differences among means were detected at a 5% level. There was no effect (P > 0.05) of pre-weaning management on carcass characteristics, surface redness (a* value), lightness (L* value), yellowness (b* value), color stability (R630/580), pH, or metmyoglobin reducing activity of LL chops. Color stability (R630/580) and metmyoglobin reducing activity declined (P < 0.05) during storage in both CR and MR chops. In contrast, lipid oxidation, lightness (L* value), yellowness (b* value), and hue value of the chops increased (P < 0.05) in both treatments during storage. Artificial raising on milk replacer for 60 d pre-weaning period did not influence color and oxidative stability of lambs finished on a high-concentrate diet. Carcass characteristics, color stability, and lipid oxidation were comparable in lambs raised through conventional method and those raised artificially on milk-replacer. These findings indicate that milk-replacer could be employed as a practical approach for artificial rearing in lamb production.

Topical Application of Acerola Cherry Powder in Combination With Rosemary Extract Extends the Shelf Life of Beef Chuck Roll and Bone-In Short Rib Steaks

Improving the shelf life of steaks from beef chuck rolls and bone-in short ribs, items commonly exported, will increase the demand of beef in international markets. Our objectives were to determine the effect of topically applying combinations of acerola cherry powder and rosemary extract on steak color and lipid oxidation of beef chuck roll and bone-in short rib. USDA Choice beef chuck rolls (Institutional Meat Purchase Specifications [IMPS] 116A; N=9) andbone-in short ribs (IMPS 123A; N=18) were aged (0°C) 28 d and cut into 1.0 cm-thick steaks. Steak treatments included the following: untreated control (C) or topically sprayed (2 mL) with an acerola cherry powder solution (0.05% A), rosemary extract solution (0.10% R), or mixture of acerola cherry powder and rosemary extract (M1=0.05% A+0.1% R; M2=0.1% A+0.1% R; M3=0.05% A+0.2% R; M4=0.1% A+0.2% R). On day 0 of retail display, oxygen consumption, metmyoglobin-reducing activity, and lipid oxidation were measured. Lipid oxidation was evaluated again following 4 d of retail display. Chuck roll steak color was scored twice daily, whereas short rib lean and bone marrow color were scored once daily throughout 4 d of retail display. Treating chuck roll steaks with M2, M3, and M4 decreased lipid oxidation compared to C and A (P=0.004). In short rib steaks, lipid oxidation remained constant from day 0 to 4 treated with M4 but increased for all other treatments (P<0.001). Chuck roll steaks treated with A, M2, and M3 were redder than C steaks (P=0.001). On days 0 and 4, untreated bone marrow was less red than all the antioxidant treated bone marrow (P=0.011). Antioxidant treatment did not improve subjective lean color for the chuck roll (P=0.324) or bone-in short rib (P=0.081). Topical application of M4 (0.1% acerola cherry powder and 0.2% rosemary extract) reduced lipid oxidation in both chuck roll and bone-in short rib steaks. Additionally, antioxidants alone or in combination with one another improve objective redness scores by up to 2 points; however, the subjective color panel did not observe lean color improvement.

Color Stability During Retail Display Differs Among Muscles in Pork

The objectives of this study were to determine differences in color stability among pork muscles and whether changes in color measurements for longissimus dorsi (LD) were related to changes for triceps brachii (TB) or psoas major (PM). The LD, TB, and PM from 20 pigs were aged in vacuum packages for 21 d, then fabricated into 3 chops per muscle. All chops from a single muscle were overwrapped, displayed for 5 d under constant lighting, and evaluated daily for instrumental color, myoglobin forms, and subjective visual discoloration. Chops were removed on day 1, 3, or 5 to measure oxygen consumption (OC) and metmyoglobin reducing activity (MRA). Data were analyzed using the MIXED procedure of SAS as repeated measures. Pearson correlation coefficients were determined using the CORR procedure. Over the 5-d display period, TB and PM chops had greater changes in a*, b*, chroma, 630/580 nm ratio, deoxymyoglobin, and oxymyoglobin compared to LD chops (display time×muscle interaction P≤0.01), but TB and PM did not differ from each other (P≥0.07). Conversely, LD had decreased OC and increased MRA on each display day compared to TB and PM (P<0.01). Using 20% discolored on day 5 of display as a threshold for acceptability, 85% of LD samples were considered acceptable whereas only 5% and 20% of TB and PM samples were considered acceptable, respectively. Changes in LD were correlated with TB and PM changes for redness (0.51≤r≤0.55; P≤0.02), and they trended toward a correlation with changes in TB and PM 630/580 nm ratio and hue angle (0.39≤r≤0.63). Chops from TB and PM were less color stable during display, but LD changes were not consistently correlated with changes in other muscles.

The effect of succinate on color stability of Bos indicus bull meat: pH-dependent effects during the 14-day aging period

Bos taurus indicus bulls are very susceptible to pre-slaughter stress, which directly impacts the decline in muscle pH, leading to darker meat. The aim was to investigate the effect of succinate and atmosphere on the color stability of Nellore (Bos taurus indicus) Longissimus lumborum steaks classified by ultimate pH (pHu): normal pHu (5.40 ≤ pHu ≤ 5.79) and high pHu (pHu ≥ 5.80). The experimental treatment systems were: (i) vacuum packaging without succinate injection, (ii) HiOx-MAP (80 % O2 + 20 % CO2), and (iii) HiOx-MAP (80 % O2 + 20 % CO2) enhanced with sodium succinate injection (pH 5.4). Steaks from all treatment systems were stored at 4 °C for 14 days and tested for instrumental color, myoglobin content, oxygen consumption (OC), metmyoglobin-reducing activity (MRA), lipid oxidation, and microbiological analysis. High and normal pHu vacuum-packaged steaks exhibited greater color stability due to higher MRA. High and normal pHu steaks packaged with HiOx-MAP or HiOx-MAP enhanced with succinate showed improved color due to lower deoxymyoglobin content (%DMb) and OC up to the eighth day of storage. Still, succinate injection promoted increased (P < 0.05) lipid oxidation in normal pHu steaks and reduced MRA after 14 days. These findings emphasize the intricate interplay between pHu and packaging systems on Bos taurus indicus meat quality. Further research in this area could contribute to a better understanding of meat color abnormalities and provide insights into potential meat preservation and enhancement strategies.

Metmyoglobin reducing activity and meat color: A review

Meat color is a crucial factor that determines customer purchasing decisions. Metmyoglobin reducing activity is essential in the preservation of meat quality since it directly influences color stability. Metmyoglobin, an oxidized form of myoglobin found in meat, is converted to its reduced, oxygen-binding state, oxymyoglobin, in this process. A number of both internal and external factors closely control the activity of metmyoglobin reduction. Intrinsic considerations include the pH of the meat, which affects the redox potential and, as a result, the effectiveness of metmyoglobin reduction. The presence of other reducing agents, such as enzymatic systems, also aids in the reduction process. Extrinsic factors such as storage conditions and temperature have an effect on metmyoglobin production, with oxygen exposure, light, and long storage durations all contributing to undesirable discoloration. Furthermore, differences in metmyoglobin reducing activity are detected across meat types and animal breeds, emphasizing the need to address meat sources in quality management. This review aims to define the current understanding of factors that influence metmyoglobin reduction in meat, with special emphasis on recent advancements in this field.

Effects of Light and Oxygen Conditions on Nonenzymatic Metmyoglobin Reduction In Vitro

Previous research indicated that inherently present electron donors and carriers contribute to nonenzymatic metmyoglobin reduction. However, limited knowledge is currently available on how light and oxygen influence nonenzymatic metmyoglobin reduction. The objective of this study was to evaluate the effect of light and oxygen levels on nonenzymatic metmyoglobin reduction in vitro. Two experiments were conducted using equine metmyoglobin solution at pH 5.6 (represents typical postmortem muscle pH) with different electron donors and electron carriers in a 96-well plate. A gas blend of 80% oxygen and 20% carbon dioxide or a pure 99.9% nitrogen gas was bubbled in phosphate buffers and myoglobin solutions to create 2 oxygen levels (low oxygen [4%] and high oxygen [160%]). The desired dissolved oxygen content was measured using a NeoFox oxygen probe (atmospheric oxygen level was 20% oxygen). There were significant effects of electron donors, carriers, and light on nonenzymatic metmyoglobin reduction. Ascorbate and nicotinamide adenine dinucleotide reduced form (NADH) in the presence of methylene blue and ethylenediaminetetraacetic acid (EDTA) exhibited a greater nonenzymatic metmyoglobin reduction in light than dark. An increase in nonenzymatic metmyoglobin-reducing activity (P&amp;lt;0.0001) was observed for the combination of NADH+methylene blue+EDTA in the high-oxygen condition in comparison with the low-oxygen levels. The results indicate that light and oxygen levels increase nonenzymatic metmyoglobin reduction. Characterizing the cofactors required for nonenzymatic metmyoglobin reduction and understanding the conditions conducive to reduction enhance knowledge related to meat color changes.

Relationships Among Initial Color or Biochemical Traits and Final Discoloration in the Pork Longissimus Dorsi, Triceps Brachii, and Psoas Major

The goal was to determine relationships between color or biochemical traits at the beginning of retail display (day 1) and final discoloration (day 5) in longissimus dorsi (LD), triceps brachii (TB), and psoas major (PM) and determine what combination of initial traits was most predictive of final discoloration in each muscle. Muscles from 20 pigs were aged in vacuum packages and fabricated to yield 3 chops per muscle. These 3 chops from the same muscle from a single pig were displayed together under constant lighting for up to 5 d. On day 1, all chops in a package were evaluated for visual dis-coloration, instrumental color, and myoglobin (Mb) forms. One chop on day 1 was evaluated for oxygen consumption (OC), metmyoglobin-reducing activity, and Mb content. Final visual discoloration and 630/580 nm ratio were evaluated on one chop from each muscle on day 5. Pearson correlation coefficients were compared between LD, TB, and PM using Fisher’s z test in SAS. Stepwise regression models were developed using the REG procedure. All initial traits were correlated to final visual discoloration and 630/580 nm ratio in TB and PM (|0.47|≤r≤|0.72|), except redness, day 1 630/580 nm ratio, OC, and Mb (P≥0.07). Final LD 630/580 nm ratio was correlated to initial lightness, redness, hue angle, deoxymyoglobin, and pH (|0.48|≤r≤|0.75|). Initial lightness and Mb (0.20≤partial R2≤0.21) were most predictive of final LD visual discoloration (R2=0.33). Yellowness was most predictive of 630/580 nm ratio for all muscles (0.32≤partial R2≤0.85). Correlations were generally stronger in TB and PM compared with LD but did not differ from each other (P≥0.17). In all muscles, color-stable chops were initially darker, were less yellow, and had lesser hue angles.

62 Awardee Talk: Correlation Between Color Parameters and Internal and Surface Metmyoglobin Content of thePsoas Major Muscle

Abstract Meat discoloration starts from the interior and rises to the surface of steaks. Recently developed near-infrared single-fiber probe (SFP) in our laboratory allows characterizing interior color changes. The objective was to determine how changes in surface and interior metmyoglobin correlate with color changes in psoas major muscle during retail display. Seven USDA Select tenderloins were collected from a commercial processing facility. Steaks were cut from each muscle and placed in polyvinyl chloride overwrap trays for retail display. The SFP was a 400-µm fiber in a 5-gauge needle and inserted into the muscle at five positions with each position increasing in depth by mm. A mathematical model developed in MATLAB determined the percent metmyoglobin at each depth and day. Surface color was analyzed using a HunterLab MiniScan spectrophotometer each day and percent metmyoglobin was determined. Steaks were randomly assigned to analysis of oxygen consumption (OC) and metmyoglobin reducing activity (MRA) of the interior and retail surfaces on d 0, d 3, and d 5 of display. Pearson’s correlation coefficients were used to evaluate the relationship between calculated percentages, color stability parameters, and retail color with significance considered at a P &amp;lt; 0.05. Metmyoglobin determined by the SFP increased at all depths during display with greater metmyoglobin at shallower depths. Metmyoglobin calculated by the SFP at mm and by HunterLab spectrophotometer were strongly negatively (P &amp;lt; 0.05) correlated with a* values during retail display. The MRA determined using the retail surface was strongly negatively (P &amp;lt; 0.05) correlated with HunterLab surface metmyoglobin and SFP metmyoglobin at mm depth. The OC of the retail surface was moderately negatively correlated (P &amp;lt; 0.05) with HunterLab surface metmyoglobin and SFP metmyoglobin at all depths. The development of internal metmyoglobin demonstrated a strong relationship with retail color and negatively impacted color stability attributes.

Influence of ultrasound intensities on colour, oxidative stability, and texture of Longissimus lumborum steaks from Nellore cattle

SummaryThis research aimed to evaluate the influence of different high‐intensity ultrasound (HIU) levels (control: 0; low: 276.36; moderate: 422.67; and high: 747.79 W cm−2) and stored in aerobic conditions for 7 days at 4 ± 1 °C on instrumental colour, metmyoglobin reducing activity (MRA), oxidative stability and texture of Longissimus lumborum (LL) from Nellore (Bos indicus) cattle. HIU moderate level samples exhibited higher (P &lt; 0.05) lipid and protein oxidation, whereas high level showed higher MRA than control, low and moderate level counterparts. An increase (P &lt; 0.05) of hue angle, MRA, lipid, and protein oxidation during refrigerated storage. Overall, the HIU levels did not influence pH, colour, texture, lipid, and protein oxidation, whereas HIU high level (HIU‐HL) improved the MRA contributing to beef colour stability.

Integrative proteomics and metabolomics profiling to understand the biochemical basis of beef muscle darkening at a slightly elevated pH.

Previous studies investigated the biochemical basis of dark-cutting conditions at elevated muscle pH (above 6), but the molecular basis at slightly above normal pH (between 5.6 and 5.8) is still unclear. The objective was to determine protein and metabolite profiles to elucidate postmortem muscle darkening at slightly elevated pH. Loins were selected based on the criteria established in our laboratory before sample collections, such as pH less than 5.8, L* values (muscle lightness) less than 38, and not discounted by the grader (high-pH beef with dark color are discounted and not sold in retail stores). Six bright red loins (longissimus lumborum) at normal-pH (average pH = 5.57) and six dark-colored strip loins at slightly elevated pH (average pH = 5.70) from A maturity carcasses were obtained within 72-h postmortem from a commercial beef purveyor. Surface color, oxygen consumption, metmyoglobin reducing activity, protein, and metabolite profiles were determined on normal-pH and dark-colored steaks at slightly elevated pH. Enzymes related to glycogen metabolism and glycolytic pathways were more differently abundant than metabolites associated with these pathways. The results indicated that oxygen consumption and metmyoglobin reducing activity were greater (P < 0.05) in darker steaks than normal-pH steaks. Enzymes involved with glycogen catabolic pathways and glycogen storage disease showed lower abundance in dark beef. The tricarboxylic acid metabolite, aconitic acid, was overabundant in darker-colored beef than normal-pH beef, but glucose derivative metabolites were less abundant. The majority of glycogenolytic proteins and metabolites reported as overabundant in the previous dark-cutting studies at high pH (>6.4) also did not show significant differences in the current study. Therefore, our data suggest enzymes involved in glycogen metabolism, in part, create a threshold for muscle darkening than metabolites.

The retail color characteristics of vacuum-packaged beef m. longissimus lumborum following long-term superchilled storage

This study investigated whether beef m. longissimus lumborum (LL) can be merchandised under retail conditions, following long-term superchilled storage (−1 °C). At 24 h post-mortem, the LL from left side of beef carcasses (n = 5) were fabricated into vacuum packaged beef thick-cuts, and then stored for 0, 2, 4, 8, 12, 16, or 20 weeks under superchilled conditions (−1 °C). Following storage, beef cuts were fabricated into steaks and aerobically displayed (0– 4 °C) for 5 days. Instrumental color, percentage of myoglobin redox forms, metmyoglobin reducing activity, oxygen consumption, and lipid oxidation were evaluated. After 4 weeks, the steaks had the highest a*, b* and chroma values between 1 and 3 days of display. Longer superchilled storage resulted in a rapid increase in discoloration and lipid oxidation which were observed in samples during display. Specifically, the a* values of steaks superchilled for 16 and 20 weeks approached the unacceptability threshold (a* ≥ 14.5) after 3 days of display.

Production system influences color stability and lipid oxidation in gluteus medius muscle.

We aimed to evaluate the color and oxidative stability of beef gluteus medius (GM) from cattle raised in organic and non-organic production systems. The GM samples (n = 10) were obtained from organic (ORG; n = 5) or non-organic (NORG; n = 5) beef samples, sliced into 2.54-cm steaks, packaged in aerobic conditions, and stored for nine days at 4°C. ORG and NORG steaks were compared regarding myoglobin concentration, pH, instrumental color, delta E (ΔE), metmyoglobin reducing activity (MRA), and lipid oxidation on days 0, 5, and 9. Feeding system did not influence (p>0.05) the myoglobin concentration. ORG steaks exhibited greater (p<0.05) meat pH, yellowness, and MRA, whereas NORG steaks exhibited greater (p<0.05) redness, chroma, R630/580, delta E, and lipid oxidation. ORG and NORG steaks exhibited similar (p>0.05) lightness and hue angle. During storage, ORG and NORG exhibited an increase in muscle pH, hue angle, and lipid oxidation; and a decrease (p<0.05) in redness, yellowness, chroma, and color stability (R630/580). Both samples exhibited a stable (p>0.05) pattern for lightness and MRA. Therefore, the production system can affect beef color and lipid stability during storage.

Extending the Shelf Life of Beef Steaks Using Acerola Cherry Powder and Rosemary Extract

Improvements in retail shelf life of exported beef will help with merchandising and increase competitiveness in the worldwide market for United States beef products. The objective of this study was to determine the effect of topically applying acerola cherry powder or rosemary extract from various suppliers on beef bone-in short rib steak and chuck roll steak shelf life. USDA Choice beef bone-in short ribs (IMPS 123A) and chuck rolls (IMPS 116A) were aged (0°C) for 28 d postfabrication. Following aging, 1.02-cm-thick steaks were cut (N = 126) and systematically assigned to a treatment based on steak location within the subprimal. Treatments included untreated control (C), topically sprayed (2 mL) with an acerola cherry powder solution (0.05%) from 1 of 3 suppliers (C1, C2, C3), or topically sprayed (2 mL) with a rosemary extract solution (0.10%) from 1 of 3 suppliers (R1, R2, R3). Half of the steaks were assigned to day 0 lipid oxidation, metmyoglobin-reducing activity (MRA), and oxygen consumption; the remaining steaks were assigned to color evaluation over 4 d of retail display followed by day 4 lipid oxidation and MRA. Short rib steaks treated with antioxidants had a brighter oxygenated lean color than control steaks (P &amp;lt; 0.001). There was an interaction (P = 0.028) between time of retail display and MRA. Short rib steaks treated with C3 and R2 did not change in MRA between day 0 and 4 (P = 0.620, P = 0.428, respectively). Chuck roll steaks treated with C1, C2, C3, R2, and R3 all had a higher, or more desirable, MRA than the control steaks on day 0 (P &amp;lt; 0.001). Applying topical antioxidants improves the shelf-life stability of steaks from beef bone-in short ribs and chuck rolls aged for an extended period.

Influence of oxygen concentration on the fresh and internal cooked color of modified atmosphere packaged dark-cutting beef stored under chilled and superchilled conditions

The current research evaluated the combined effect of oxygen concentration (20%, 50% and 80% O2) and storage temperature (4°C or −1.5°C) on the fresh and internal cooked color of dark-cutting (DC) beef. Steaks were packaged in modified atmosphere packaging (MAP) over a 12-day storage period. Although the metmyoglobin reducing activity (MRA) of DC steaks decreased with increasing O2 levels, lower oxygen consumption (OC) and deeper oxygen penetration depth (OPD) improved the surface color of 50%O2-MAP and 80%O2-MAP DC steaks. 80%O2-MAP resulted in the highest (P < 0.05) percentage myoglobin denaturation and alleviated the phenomenon of persistent pink (PP) observed in DC beef. Compared with normal chilling, superchilling significantly increased the redness values of DC steaks through inhibition of lipid oxidation and enhancement of MRA, while it had no effects on PP due to the limited OPD. The results suggest that 80%O2-MAP combined with superchilling can be used to improve fresh color and minimize PP of DC beef.

Pulmonary arterial pressure in fattened Angus steers at moderate altitude influences early postmortem mitochondria functionality and meat color during retail display.

Pulmonary hypertension is a noninfectious disease of cattle at altitudes > 1524 m (5,000 ft). Mean pulmonary arterial pressures (PAP) are used as an indicator for pulmonary hypertension in cattle. High PAP cattle (≥50 mmHg) entering the feedlot at moderate elevations have lower feed efficiency as compared to low PAP cattle (< 50 mmHg). The impact of pulmonary arterial pressure on mitochondrial function, oxidative phosphorylation (OXPHOS) protein abundance, and meat color was examined using longissimus lumborum (LL) from high (98±13 mmHg; n = 5) and low (41±3 mmHg; n = 6) PAP fattened Angus steers (live weight of 588±38kg) during early postmortem period (2 and 48h) and retail display (days 1 to 9), respectively. High PAP muscle had greater (P = 0.013) OXPHOS-linked respiration and proton leak-associated respiration than low PAP muscles at 2h postmortem but rapidly declined to be similar (P = 0.145) to low PAP muscle by 48h postmortem. OXPHOS protein expression was higher (P = 0.045) in low PAP than high PAP muscle. During retail display, redness, chroma, hue, ratio of reflectance at 630 and 580nm, and metmyoglobin reducing activity decreased faster (P < 0.05) in high PAP steaks than low PAP. Lipid oxidation significantly increased (P < 0.05) in high PAP steaks but not (P > 0.05) in low PAP. The results indicated that high PAP caused a lower OXPHOS efficiency and greater fuel oxidation rates under conditions of low ATP demand in premortem beef LL muscle; this could explain the lower feed efficiency in high PAP feedlot cattle compared to low PAP counterparts. Mitochondrial integral function (membrane integrity or/and protein function) declined faster in high PAP than low PAP muscle at early postmortem. LL steaks from high PAP animals had lower color stability than those from the low PAP animals during simulated retail display, which could be partially attributed to the loss of muscle mitochondrial function at early postmortem by ROS damage in high PAP muscle.

Antioxidant, Antimicrobial and Metmyoglobin Reducing Activity of Artichoke (Cynara scolymus) Powder Extract-Added Minced Meat during Frozen Storage.

The present study aimed to investigate the bioactive compounds in artichoke (Cynara scolymus) powder, having antioxidant and antimicrobial activity, and to determine the effectiveness of artichoke (C. scolymus) powder extract within the minced meat. C. scolymus was extracted using two different methods. The method incorporating high phenolic and flavonoid content levels was used in other analyses and the phenolic and flavonoid contents in C. scolymus extract was determined using LC-QTOF-MS. Antioxidant, antimicrobial, and metmyoglobin (metMb) reducing activities and pH values of the extract-added minced meat samples were measured for 10 days during storage. DPPH, FRAP, and ABTS were used in the antioxidant analyses. The antimicrobial activity of C. scolymus extract was evaluated on five different food pathogens by using the disc diffusion method. The most resistant bacterium was found to be Listeria monocytogenes (18.05 mm ± 0.24). The amount of metMb was measured in the minced meat sample that was added to the extract during storage (p < 0.05). MetMb formation and pH value on the sixth day of storage were found to be at lower levels than in the control group. In conclusion, C. scolymus exhibited a good antimicrobial and antioxidant effect and can be used in storing and packaging the food products, especially the meat and meat products.

Changes in color, myoglobin, and lipid oxidation in beef patties treated by dielectric barrier discharge cold plasma during storage

The objective of this work was to investigate the changes in color, metmyoglobin reducing activity (MRA), and lipid oxidation (TBARS) and their relationships in beef patties treated by dielectric barrier discharge cold plasma (DBD-CP) at different voltages and frequencies during storage at 4 °C. DBD-CP treatment, including treatment voltages and frequencies, caused the decrease of a⁎ value and MRA (P < 0.05), promoted the accumulation of metmyoglobin (P < 0.05), and significantly increased TBARS values (P < 0.05). It was the first time revealed that the effect of treatment voltage on the quality of beef patty was greater than that of frequency. In addition, there were significant and strong positive correlations between a⁎ value and MRA and negative correlations between a⁎ value, metmyoglobin (MMb)% and TBARS. Taken together, Data demonstrated that DBD-CP treatment can significantly affect meat redness, Mb contents, MRA, and lipid oxidation in ground beef during storage, and accelerate discoloration and lipid oxidation of meat.