scholarly journals 78 Effects of extended aging, modified atmospheric packaging, and display time on metmyoglobin reducing activity and oxygen consumption of high-pH beef

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 26-26 ◽  
Author(s):  
Ranjith Ramanathan ◽  
Andrea English ◽  
Gretchen Mafi ◽  
Deb VanOverbeke
Keyword(s):  
Oxygen Consumption ◽  
Biochemical Properties ◽  
Display Time ◽  
High Ph ◽  
Aging Period ◽  
Modified Atmospheric Packaging ◽  
Extended Aging ◽  
Reducing Activity ◽  
Ph Range ◽  
Effects Of Aging

Abstract Metmyoglobin reducing activity (MRA) and oxygen consumption (OC) are two important biochemical processes that can influence beef color. Several studies have determined the effects of aging and modified atmospheric packaging (MAP) on biochemical properties of normal-pH beef (5.5–5.7 pH range). However, limited knowledge is currently available on the effects of aging and MAP on biochemical properties of high-pH beef (> 6.2). Therefore, the objective was to determine the effects of extended aging, MAP, and display time on MRA and OC of high-pH beef. Ten USDA Choice (pH = 5.6) and ten ‘No-Roll’ dark cutting (high-pH; pH > 6.4) strip loins were obtained from a commercial packing plant within 72 hours of harvest. Loins were vacuum packaged and aged for 0, 21, 42, and 62 days at 4 °C. Following aging, from each normal- and high-pH loin sections, 2.5cm thick steaks were cut and packaged in PVC, high oxygen- (HiOx-MAP), and carbon monoxide modified atmospheric (CO-MAP) packaging. The surface color, MRA, and OC were determined on day 0 and 6 of the respective aging period. The experiment was replicated ten times (n = 10). High-pH steaks in all packaging and aging times had more stable red color than normal-pH steaks. High-pH steaks packaged in PVC and HiOx-MAP had greater (P < 0.05) MRA than normal-pH steaks. There were no differences (P > 0.05) in MRA between normal- and high-pH steaks on day 21 when steaks were packaged in CO-MAP, but high-pH had greater (P < 0.05) MRA on day 62. At all aging periods, high-pH steaks had greater (P < 0.05) OC than normal-pH steaks. However, a decrease in OC was greater (P < 0.05) for high-pH than normal-pH steaks. The results suggest that normal- and high-pH beef have different trends for the changes in MRA and OC.

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

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
L. Yoder ◽  
A. Cassens ◽  
G. Mafi ◽  
D. VanOverbeke ◽  
R. Ramanathan
Keyword(s):  
Oxygen Consumption ◽  
Modified Atmosphere Packaging ◽  
Processing Plant ◽  
Glycogen Depletion ◽  
Display Time ◽  
Rigor Mortis ◽  
Biochemical Basis ◽  
Time Interaction ◽  
Modified Atmospheric Packaging ◽  
Muscle Ph

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.

scholarly journals 110 Metmyoglobin reducing activity and oxygen consumption properties of atypical dark-cutting beef

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 22-22
Author(s):  
Ranjith Ramanathan ◽  
Andrew M Cassens ◽  
Laura Yoder ◽  
Gretchen G Mafi
Keyword(s):  
Oxygen Consumption ◽  
Biochemical Properties ◽  
Agricultural Products ◽  
Processing Plant ◽  
Surface Color ◽  
Beef Processing ◽  
Red Color ◽  
Initial Ph ◽  
Dark Color ◽  
Reducing Activity

Abstract Deviation from characteristic bright-red color during grading leads to discounted carcass price and value. Dark-cutting carcasses are examples of color deviation due to high-pH. However, atypical dark-cutters are not discounted at grading but have a dark color compared to normal-pH beef. Limited knowledge is currently available on the biochemical properties of atypical dark cutting beef compared with normal-pH beef. Therefore, the objective of the study was to determine metmyoglobin reducing activity and oxygen consumption of atypical dark-cutting beef. Strip loins from atypical dark-cutting (ADC; selected based on HunterLab L* values and pH less than 5.8 and not discounted by grader) 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, Oklahoma. pH, color, oxygen consumption, and metmyoglobin reducing activity of atypical dark cutters and normal pH loins were determined on d3 postmortem. The surface color was determined using a HunterLab Miniscan spectrophotometer. Reflectance-based methods using K/S ratios were utilized to determine oxygen consumption and metmyoglobin reducing activity. The data were analyzed using the Mixed Procedure of SAS and the experiment was replicated 10 times (n = 10). There were no differences in initial pH (C = 5.46 and ADC = 5.6 atypical dark-cutter; P = 0.05) between normal-pH and atypical dark cutters. However, atypical dark cutters had lower lightness (L* values; C = 44.2 and ADC = 38.4), redness (a* values; C = 28.6 and ADC = 25.2), and red intensity (chroma; C = 40.2 and ADC = 36.4) compared with normal-pH. Further, atypical dark cutters had greater (P &lt; 0.05) oxygen consumption and metmyoglobin reducing activity than normal-pH. The results suggest that atypical dark cutters and normal-pH beef have different biochemical properties.

Effects of Aging on the Solubility of Palladium

1995 ◽  
Vol 412 ◽  
Author(s):  
C. Oda ◽  
H. Yoshikawa ◽  
M. Yui
Keyword(s):  
Aqueous Solution ◽  
Aging Time ◽  
Room Temperature ◽  
High Level Waste ◽  
Anaerobic Conditions ◽  
Dilute Aqueous Solution ◽  
Waste Repository ◽  
Ph Range ◽  
Effects Of Aging ◽  
High Level

AbstractPalladium solubility was measured in a dilute aqueous solution at room temperature in the pH range from 3 to 13 under anaerobic conditions. Crystalline Pd metal was clearly visible and the concentration of palladium in solution decreased gradually with aging time. The palladium concentrations in solution were less than 9.4×10-10M in the pH range from 4 to 10 and increased to 10-7M in the pH range greater than 10. This study suggests that palladium concentrations in certain high-level waste repository environments may be limited by Pd metal and may be less than 10-9M.

scholarly journals Effects of Finishing Diet and Packaging on Longissimus Dorsi Color

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
M. Perry ◽  
M. Pfeiffer ◽  
D. VanOverbeke ◽  
R. Ramanathan ◽  
G. Mafi
Keyword(s):  
Carbon Dioxide ◽  
Lipid Oxidation ◽  
Thiobarbituric Acid ◽  
Longissimus Dorsi ◽  
Display Time ◽  
Beef Processing ◽  
Modified Atmospheric Packaging ◽  
Strip Loin ◽  
Muscle Color ◽  
Beef Color

ObjectivesMeat color is extremely influential in purchasing decisions as consumers associate a bright-red color with freshness. The type of finishing diet can influence beef color. Previous studies have shown that grass-finished cattle have darker muscle color than grain-finished cattle. With the use of modified atmospheric packaging (MAP), beef purveyors are able to vary the gas compositions within a package and enhance beef color. However, limited studies have determined the effects of modified atmospheric packaging on grass-finished beef color. The objective of this study was to determine how finishing diet and packaging type affects the color of the longissimus dorsi (LD) muscle.Materials and MethodsDuring the stocker period, all of the cattle were on a forage diet. Cattle were then randomly assigned to either a conventional grain-based diet or an alfalfa pasture diet for finishing. Both conventionally and pasture-finished cattle were fed for 91 d. Cattle were slaughtered on the same day at a commercial beef processing facility under normal conditions and chilled for approximately 30 h. After grading, one strip loin from each carcass was collected and transported to Oklahoma State University. At 11 d postmortem, one steak (n = 60) from each strip loin was vacuum packaged and randomly assigned to display. Those steaks were then randomly assigned to PVC, HiOx-MAP (80% oxygen and 20% carbon dioxide), or CO-MAP (0.4% carbon monoxide, 69.5% nitrogen, and 30% carbon dioxide) packaging and were displayed under retail conditions for 5 d. Muscle darkening (MD), muscle color (MC), and surface discoloration (SD) were all analyzed by a trained panel (n = 6). MD was evaluated only on d 0 and MC and SD were scored once every 24 h for 0, 1, 2, 3, and 4 d. Lipid oxidation was measured by thiobarbituric acid reactive substances (TBARS) assay on d 4. Data were analyzed using the Mixed Procedure of SAS.ResultsThere was a significant display day by finishing diet by packaging interaction (P < 0.05) for muscle color and surface discoloration. There was also a significant finishing diet by packaging interaction (P < 0.05) for muscle darkening. Steaks packaged in HiOx-MAP remained the most stable in color and the brightest cherry-red colored throughout display time (P < 0.05) compared with other packaging types. PVC was the most discolored (P < 0.05) on d 3 and 4 when compared to HiOx-MAP and CO-MAP with the grain-finished PVC packaged steaks showing the most discoloration on d 4. Pasture-finished steaks packaged in CO-MAP displayed the darkest colored muscle (P < 0.05) on d 0. Steaks packaged in PVC had a higher amount of lipid oxidation (P < 0.05) compared with other packaging types.ConclusionThese results indicate that HiOx-MAP more effectively maintains the desired beef color of bright cherry-red for pasture-finished beef. The results also indicate that the use of appropriate packaging type can minimize the losses due to discoloration of steaks from either grain or grass-finished beef.

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

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
A. Cassens ◽  
G. Mafi ◽  
D. VanOverbeke ◽  
R. Ramanathan
Keyword(s):  
Modified Atmosphere Packaging ◽  
Processing Plant ◽  
High Ph ◽  
Beef Processing ◽  
Modified Atmospheric Packaging ◽  
Significant Difference ◽  
Muscle Ph ◽  
Beef Steaks ◽  
Retail Display ◽  
Muscle Color

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.

scholarly journals ENHANCED ENZYMATIC ACTIVITY OF STREPTOMYCES GRISEOPLANUS L-ASPARGINASE VIA ITS INCORPORATION IN AN OIL-BASED NANOCARRIER

2020 ◽  
pp. 203-210
Author(s):  
ABEER A. EL-HADI ◽  
HANAN MOSTAFA AHMED ◽  
RANIA A. ZAKI ◽  
AMIRA MOHAMED MOHSEN
Keyword(s):  
Thermal Stability ◽  
Oleic Acid ◽  
Enzymatic Activity ◽  
Specific Activity ◽  
Residual Activity ◽  
Tween 80 ◽  
Biochemical Properties ◽  
Lymphocytic Leukemia ◽  
Tween 20 ◽  
Ph Range

Objective: L-asparaginase (L-asp) is a vital enzyme used as a therapeutic agent in combination with other drugs in the treatment of acute lymphoma, melanosarcoma and lymphocytic leukemia. Immobilization of enzymes through loading on nanoemulsion (NE) results in some advantages such as enhancing their stability and increasing their resistance to proteases. Aim of the present study is to formulate L-asp loaded nanoemulsion to enhance its efficiency and thermal stability. Methods: Nanoemulsion loaded with L-asp crude extract (specific activity 13.23U/mg protein) was prepared employing oleic acid as oil, tween 20/tween 80 as surfactants and propylene glycol (PG) as co-surfactant. L-asp loaded NE underwent several thermodynamic stability studies and the optimized formulae were further examined for their biochemical properties and thermal stability. Results The developed formulations were spherical in shape and their sizes were in the nanometric dimensions with negatively charged zeta potential values. Upon comparing the enzyme activity of L-asp loaded NE employing tween 20 (F1) or tween80 (F4) at different concentrations, the results revealed that F4 NE showed higher enzymatic activity [323 U/ml] compared to F1 NE [197 U/ml] at the same concentration. The nanosized immobilized L-asp was more stable in the pH range from 8 to 8.5 as compared to free L-asp. The immobilized enzyme preserved about 59.11% of its residual activity at 50 °C; while free L-asp preserved about 33.84%. Conclusion: In the view of these results, NE composed of oleic acid, tween 80 and PG represents a promising dosage form for enhancing the activity and stability of Streptomyces griseoplanus L-asp.

scholarly journals THE ISOLATED PERFUSED BOVINE LIVER

1961 ◽  
Vol 113 (6) ◽  
pp. 981-996 ◽  
Author(s):  
Niles D. Chapman ◽  
Patrick D. Goldsworthy ◽  
Wade Volwiler ◽  
Lloyd M. Nyhus ◽  
Andrew J. Martinis
Keyword(s):  
Oxygen Consumption ◽  
Bovine Liver ◽  
Hepatic Tissue ◽  
Normal Body Temperature ◽  
Blood Flows ◽  
Smooth Musculature ◽  
Repeated Sampling ◽  
Ph Range ◽  
Hepatectomized Animal ◽  
Isolated Liver

1. A procedure is described for surgically isolating and artificially perfusing the liver of the young bovine. Heparinized autogenous blood from the hepatectomized animal diluted with Krebs-Ringer-bicarbonate solution is employed as the perfusate. 2. This preparation has been satisfactorily reproducible in this laboratory in more than 90 separate sequential perfusions. Absence of a sensitive hepatic venous smooth musculature contributes to the ability to maintain satisfactory perfusion for as long as 24 hours. 3. The perfusate was usually maintained bacterially free for at least the first 12 hours of perfusion without the use of antibiotics. The perfusate was maintained at normal body temperature and, by varying the CO2 content of the oxygenating gas, within a physiological pH range. The importance of these features when studying problems of intermediary biochemistry and ultrastructure is emphasized. 4. The liver of the bovine calf is sufficiently large to permit (a) simultaneous and independent perfusion through the hepatic artery and portal vein, and (b) repeated sampling of hepatic tissue without interruption of the circulation. 5. Excellent, viable condition of the isolated liver, throughout many hours of perfusion, was demonstrated by steady state of oxygen consumption, efficient clearance of bromsulphalein dye, continuous secretion of bile, constancy of blood flows and pressures, and very minimal alterations from normal in histologic and ultrastructural detail.

Factors influencing the inorganic speciation of trace metal cations in fresh waters

1999 ◽  
Vol 50 (4) ◽  
pp. 367 ◽  
Author(s):  
Jonathan P. Kim ◽  
Keith A. Hunter ◽  
Malcolm R. Reid
Keyword(s):  
Natural Waters ◽  
Major Ions ◽  
Divalent Cations ◽  
Ion Composition ◽  
High Ph ◽  
River Waters ◽  
Inorganic Complexes ◽  
Effects Of Ph ◽  
Ph Range ◽  
Inorganic Speciation

The effects of pH and major ion composition on the chemical speciation of the divalent cations of Co, Ni, Cu, Zn, Pb and Cd have been examined after consideration of the available thermodynamic database for solution complexes of these ions. Calculations were made for two model river waters representing the 1% and 99% extremes in composition of global river waters. The results show that inorganic speciation behaviour is of two characteristic types: (a) Cu, Zn and Co are dominated by bis-hydroxy- complexes at high pH and show the greatest reduction in the fraction of free aquo ion with increasing pH; (b) Pb, Ni and Cd are dominated by carbonato- complexes at high pH and show a more gradual decrease in the fraction of free aquo ion with increasing pH. For Cu, Pb and Ni significant fractions of the labile forms of these metal ions are present as inorganic complexes in the pH range of most natural waters, whereas for Zn, Co and Cd this is true only at moderately high pH (pH >7.5). Complexing with the major ions SO42– and Cl– is important only at low pH in river waters of high ionic strength.

Radiolysis of aqueous chloroform solutions

1970 ◽  
Vol 48 (2) ◽  
pp. 271-276 ◽  
Author(s):  
B. J. Rezansoff ◽  
K. J. McCallum ◽  
R. J. Woods
Keyword(s):  
Oxalic Acid ◽  
Formic Acid ◽  
Hydroxyl Radicals ◽  
Ph Effect ◽  
Hydrogen Ions ◽  
Γ Radiation ◽  
High Ph ◽  
Hydrated Electrons ◽  
Presence And Absence ◽  
Ph Range

Saturated aqueous chloroform solutions (0.07 M) with pH ranging from 0.8 to 12.6 have been irradiated with 60Co γ-radiation in the presence and absence of air. G(Cl− + ClO−) increases with increasing pH in the pH range 1–3 (aerated solutions) or 3–6 (deaerated solutions) and again at pH greater than 10.5. The variation in yield from aerated solutions in the region pH 1–3 is attributed to competition between chloroform and hydrogen ions for hydrated electrons. However, such competition cannot account for the pH effect observed in deaerated solutions between pH 3 and 6. Increased yields from both aerated and deaerated solutions at high pH are attributed to the formation of O− by reaction of hydroxyl radicals and hydroxide ions. Formic acid and oxalic acid have been identified as minor products when aerated chloroform solutions are irradiated.

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