Bovine mitochondrial oxygen consumption effects on oxymyoglobin in the presence of lactate as a substrate for respiration

Research suggests that NADH formed from lactate addition can increase mitochondrial oxygen consumption. However, limited research has assessed the subsequent effects of lactate-mediated mitochondrial oxygen consumption on oxymyoglobin. Therefore, our objective was to assess the effects of bovine mitochondrial oxygen consumption on oxymyoglobin in the presence of lactate, LDH, and NAD. Isolated beef cardiac and skeletal muscle mitochondria (n = 5) were reacted with lactate (40 mM), LDH (100 units), and NAD (0.02 mM) to initiate oxygen consumption. Myoglobin redox state was measured to assess the effects of oxygen consumption on oxymyoglobin. The addition of lactate–LDH–NAD to mitochondria increased (p < 0.05) both oxygen consumption and conversion of oxymyoglobin to deoxymyoglobin compared with control mitochondria without substrates. The addition of antimycin A to mitochondria decreased oxygen consumption and deoxymyoglobin formation (p < 0.05). The results suggest that increased oxygen consumption can influence myoglobin redox state and this effect might be partially responsible for the darkening effect in lactate enhanced beef.     

Effects of 4-hydroxy-2-nonenal on beef heart mitochondrial ultrastructure, oxygen consumption, and metmyoglobin reduction

The effects of 4-hydroxy-2-nonenal (HNE) on mitochondria isolated from bovine hearts (n = 5) were assessed using ultrastructure, oxygen consumption, membrane permeability, HNE binding, and metmyoglobin reduction in vitro. Pre-incubation (pH 5.6 and 7.4 at 25 °C) of mitochondria with HNE decreased oxygen consumption compared with samples without HNE (P < 0.05). Electron microscopy revealed that HNE-treated mitochondria were swollen and had increased membrane permeability at pH 7.4, compared with ethanol controls. Conversely, mitochondria incubated with HNE at pH 5.6 had decreased volume and permeability. Fluorescence studies indicate that HNE binds to the membrane of mitochondria isolated from bovine cardiac muscle (at pH 5.6 and 7.4). HNE-treated mitochondria at both pH 5.6 and 7.4 had lower metmyoglobin reduction and NADH dependent metmyoglobin reductase activity compared with control mitochondria without HNE (P < 0.05). In addition to covalent binding with myoglobin, HNE may influence beef color stability by interacting with mitochondria.     

Effects of pyruvate on bovine heart mitochondria-mediated metmyoglobin reduction

Pyruvate can regenerate NADH through a variety of biochemical processes. However, no meat science research has determined if NADH produced via pyruvate can be used for mitochondria-mediated metmyoglobin reduction. Thus, our objectives were to assess the effects of pyruvate on mitochondria isolated from bovine cardiac muscle: oxygen consumption and metmyoglobin reduction at pH 5.6 and 7.4, 25 °C in vitro. Both mitochondria and myoglobin were isolated from fresh bovine hearts (n = 5). Mitochondria were reacted with pyruvate (50 mM), succinate (positive control; 50 mM), and antimycin A (mitochondrial inhibitor; 0.01 mM) and oxygen consumption was measured using a Clark oxygen electrode. Mitochondria (3 mg/mL) and metmyoglobin (0.15 mM) were reacted with either pyruvate, succinate, or antimycin A for 3 h. Addition of succinate and pyruvate increased oxygen consumption and metmyoglobin reduction at pH 5.6 and 7.4 (succinate > pyruvate, P < 0.05). Addition of a complex III inhibitor (antimycin A) decreased (P < 0.05) oxygen consumption as well as metmyoglobin reduction associated with pyruvate and succinate. Results from the current study suggest that pyruvate can increase the ability of mitochondria to consume oxygen and reduce metmyoglobin.     

Effect of aging time in vacuum on tenderness,and color and lipid stability of beef from mature cows during display in high oxygen atmosphere package

The effect of aging time in vacuum on tenderness, and lipid and color stability of modified-atmosphere packaged (MAP) beef during display was evaluated in eight Friesian mature cows. Longissimus thoracis et lumborum (LTL) sections were vacuum packaged and aged for 0, 3, 6, 8, 14 and 21 days. After each aging time, the LTL sections were cut into steaks and packaged in high oxygen atmosphere (80% O₂: 20% CO₂). Meat shear force, and color and lipid stability were evaluated at 0, 3, 6, and 9 days of simulated retail display. Aging for 6 or 8 days improved beef tenderness with color stability, instrumental discoloration (R₆₃₀–R₅₈₀) and visual color evaluation in MAP similar to those of short-time aged (3 d) or un-aged (0 d) beef. Longer aging times (14 and 21 d) resulted in tenderness values similar to those obtained with meat aged for 8 days but affected negatively color and lipid stability and, consequently, reduced the shelf life of beef in MAP.     

Effects of lactate on ground lamb colour stability and mitochondria-mediated metmyoglobin reduction

Previous research suggests that lactate’s colour stabilizing effect in beef is through NADH production and antioxidant activity. However, no research has assessed lactate’s role in lamb colour. Hence, our objectives were to evaluate the effects of lactate on lamb surface discolouration, oxygen consumption, and metmyoglobin reduction. In experiment 1, lactate (final meat concentration = 2.5% w/w) was added to ground lamb (n = 20 carcasses) and patties were stored for 3 days at 1 °C in PVC packaging. Surface colour (CIE L∗ and a∗) and metmyoglobin reducing activity of ground lamb patties were measured. Addition of lactate improved colour stability and metmyoglobin reducing activity (p < 0.05). In experiment 2, mitochondria were isolated from lamb longissimus muscle (n = 3). Addition of lactate–LDH–NAD to mitochondria resulted in significant oxygen consumption and metmyoglobin reduction compared with mitochondrial controls without lactate (p < 0.05). Lactate can improve the colour stability of lamb, possibly by increasing metmyoglobin reducing activity.     

Color stability and reversion in carbon monoxide packaged ground beef

This study investigated the relationship between length (1, 2, 4, or 6 days) of exposure to carbon monoxide (CO) and the subsequent rate of loss of carboxymyoglobin color during display (0, 24, 48, 72 h) after repackaging in an oxygen permeable polyvinyl chloride (PVC) overwrap. In addition, the ability of CO to cause color reversion of metmyoglobin to carboxymyoglobin in brown colored, aged (4 days, PVC) or low oxygen-induced (2 days, (LOX-MAP) ground beef was studied. Extending CO exposure time increased overall mean redness. However, overall mean redness decreased after packages were opened. Day 6 exposed ground beef only maintained about 1.5 Minolta a∗ units higher than day 1 exposed after opened 72 h. The color of brown ground beef was converted to carboxymyoglobin upon exposure to carbon monoxide, regardless of how the initial brown color was formed. This color changes was relatively faster in LOX-MAP packaged ground beef compared to that formed by aging in PVC. Although color reversion is possible, consideration should be given to the microbiological status of the ground beef at the time of CO packaging.     

Effects of blade tenderization,aging method and aging time on meat quality characteristics of Longissimus lumborum steaks from cull Holstein cows

The effects of blade tenderization (BT), two aging methods (dry (D) and wet (W)), and aging time (2 and 23 d) on tenderness, color, and sensory properties of Longissimus lumborum muscles from 12 cull Holstein cows were evaluated. Dry-aged loins had higher combined trim and aging losses than control (C) for both D- and W-aging, mostly because of excess trim losses. BT steaks had WBSF of 33.13 N while C steaks had WBSF of 41.46 N (P = 0.09). Aging decreased WBSF. Blade tenderized steaks had higher cook loss than C steaks. Aging, W-aging, and BT × W-aging improved myofibrillar (sensory) tenderness scores. Aging and/or BT improves sensory panel tenderness cull cow Longissimus lumborum steaks. Aging and blade tenderization combined can increase tenderness and value of Longissimus steaks from cull Holstein cows.     

The effect of pH on shelf-life of pork during aging and simulated retail display

The pork industry uses pH to differentiate product of varying quality; thus, the effect of pH on shelf-life is important as time during transport is extended. The objective was to develop regression equations to predict shelf-life over a range of ultimate pH (5.42–6.26). Shelf-life was evaluated after vacuum aging pork loin sections 0, 7, 14, 21, or 28 d and during 3 d of simulated retail display (4.5 °C) for pork loin chops. Correlation coefficients indicated a strong relationship between pH and quality measurements. Regression analysis with Aging Day and pH was able to explain 87% of the variation in aerobic plate counts for pork. After 28 d of vacuum aging, loin sections from the upper end of the pH distribution had about a 3 log(1000X) greater aerobic plate count than did the lower end pH product. An increase in pH resulted in pork with lower L*, a*, b* and R₆₃₀ − R₅₈₀ values and as Aging Day increased, instrumental measurements of color increased slightly. Although higher pH is associated with improved pork quality, higher pH and longer aging periods will result in increased microbial proliferation and decreased shelf-life. Thus, an intermediate pH may provide the most desirable combination of quality and shelf-life when extensive aging is used.     

Storage length,storage temperature,and lean formulation influence the shelf-life and stability of traditionally packaged ground beef

The effect of storage length and temperature on the shelf life of three ground beef formulations (lean:fat: 73:27, 81:19 and 91:9) was investigated. Coarsely ground beef was stored at − 1.7 or 2.3 °C for up to 28 d. Traditional overwrap packages were produced every 7 d prior to retail display for 24 h. Lipid oxidation (TBARS), subjective color, instrumental color, and aerobic bacteria were evaluated after 0 and 24 h of display. Formulation influenced initial L* and subjective color values (P < 0.05). Storage temperature did not affect initial color, but product stored at 2.3 °C was more discolored after 24 h (P < 0.05). Aerobic bacteria increased as storage d and temperature increased (P < 0.05). Initial TBARS increased through d 21, but were lower after 28 d. Overall, initial characteristics depended on formulation; however, ground beef shelf-life and stability were largely influenced by storage length and storage temperature.     

Effects of dry,vacuum, and special bag aging; USDA quality grade; and end-point temperature on yields and eating quality of beef Longissimus lumborum steaks

This study evaluated the effects of three aging methods: (dry (D), wet (W), and special bag (SB)); two quality grades [USDA Choice((≥ Small⁵⁰ marbling) and Select); and two cooked end-point temperatures (62.8 °C and 71.1 °C) on physico-chemical traits of instrumental tenderness, color, and sensory properties of Longissimus lumborum beef muscle. Dry-aged loins had higher (P < 0.0001) weight loss than W or SB aged loins. However, D and SB aged loins had similar (P > 0.05) combined losses. W aged loins had higher (P < 0.01) L* values than D or SB aged loins. Warner–Bratzler shear force of steaks was not affected (P > 0.05) by aging method or quality grade but increased (P < 0.0001) as end-point temperature increased. Sensory panel evaluation also showed no effect (P > 0.05) of aging method or quality grade on myofibrillar tenderness, juiciness, connective tissue amount, overall tenderness or off flavor intensity. Steaks cooked to 62.8 °C were juicier (P < 0.05) than those cooked to 71.1 °C. Neither D nor SB aging had advantages over W aging.     

Application of biospeckle laser technique for determining biological phenomena related to beef aging

Among the features of beef quality, color is a major factor that influences marketing since it is the only characteristic consumers can see at the time of purchase, although tenderness is the organoleptic trait that most affects consumer acceptance of beef. Thus, an effective technology to predict meat quality is highly desirable for the meat industry. Among many emerging technologies, optical methods have the greatest potential since they are fast, nondestructive, and generally low cost. This study evaluated the potential application of laser biospeckle technique and its methods of image processing in order to assess and quantify biological phenomena related to beef aging. Samples of muscle Longissimus thoracis were aged for 21 days and underwent biospeckle analysis, objective color and Warner–Bratzler Shear Force (WBSF). According to the results, biospeckle laser parameters may, possibly, assess biological activity resulting from action of endogenous enzymes (calpains and cathepsins) responsible for the aging process through its correlation (R = 0.6146) with analysis of WBSF and of the correlation (−0.7973) with aging time. High correlation of biospeckle analysis, related to traditional out puts and to new proposals, were obtained to color parameters, especially hue angle (h^*) whose R value was 0.7953, redness intensity (R = 0.8120) and percentage of metmyoglobin (MMb) showed that R value of 0.9119, demonstrates the potential of this technique for evaluating quality of meat color.     

Ageing of large cuts of beef loin in vacuum or high oxygen modified atmosphere – Effect on shear force,calpain activity,desmin degradation and protein oxidation

The aim was to investigate the effect of ageing large beef cuts directly in high oxygen modified atmosphere (MA) and how ageing time in vacuum influence meat quality when followed by retail packaging in high oxygen MA. Large cuts (10 cm long) of beef loin (LD) were aged for up to 25 days postmortem in different ageing systems at 4 °C. Ageing solely in high oxygen modified atmosphere (MA, 80% O₂ + 20% CO₂) for 5 or 10 days and ageing in vacuum for 5 or 15 days followed by high oxygen MA for 5 or 10 days were compared with ageing in vacuum for 5, 15 and 25 days. Warner–Bratzler shear force, purge and cooking losses, calpain activity and desmin and carbonyl contents were measured. Shear force decreased to the same level when ageing this large beef cut solely in high oxygen MA for 5 or 10 days as when ageing in vacuum. The activity of μ-calpain disappeared, the activity of m-calpain decreased and purge loss increased between 5 and 10 days, but cooking loss and the contents of desmin and carbonyls were unaffected. The ageing time in vacuum before packaging of this large beef cut in high oxygen MA did not affect the ultimate shear force. The m-calpain activity decreased and the content of carbonyls increased compared with solely in vacuum after 15 days of total ageing, but there was no difference in the content of desmin or cooking loss between these ageing systems at the same ageing time.     

Effects of lactate and modified atmospheric packaging on premature browning in cooked ground beef patties

Our objectives were to determine the effects of lactate and modified atmosphere packaging on raw surface color, lipid oxidation, and internal cooked color of ground beef patties. Eight chubs (85% lean) were divided in half and each half was either assigned to the control (no lactate) or mixed with 2.5% lactate (w/w). Following treatment, patties were prepared and packaged in either vacuum, PVC (atmospheric oxygen level), high-oxygen (80% O₂ + 20% CO₂), or 0.4% CO (30% CO₂ + 69.6% N₂) and stored for 0, 2, or 4 days at 2 °C. After storage, raw surface color and lipid oxidation were measured and patties were cooked to either 66 °C or 71 °C. Lactate improved (p < 0.05) color stability of PVC, high-oxygen, and vacuum packaged raw patties, but had no effect (p > 0.05) on the a∗ values and visual color scores of patties in 0.4% CO. Lactate decreased (p < 0.05) lipid oxidation in all packaging atmospheres. Nevertheless, high-oxygen and PVC-packaged patties had more (p < 0.05) lipid oxidation than patties in CO and vacuum. Lactate had no effect (p > 0.05) on premature browning, whereas patties packaged in high-oxygen demonstrated premature browning. Conversely, cooked patties in 0.4% CO and vacuum were more red (p < 0.05) than both high-oxygen and PVC-packaged patties. Although lactate improved raw color stability, it did not minimize premature browning in cooked ground beef patties.     

Effects of lactate/phosphate injection enhancement on oxidation stability and protein degradation in early postmortem beef cuts packaged in high oxygen modified atmosphere

The influence of lactate/phosphate enhancement on meat color and lipid oxidation stability, tenderness, protein degradation, and protein aggregation of early postmortem beef muscles packaged in a high oxygen modified atmosphere packaging (HiOx-MAP; 80% O₂, 20% CO₂) were studied. At 24 hr postmortem, three bovine muscles (longissimus, semimembranosus, and adductor; n = 10, respectively) were enhanced (10% injection rate) with either lactate (2.5%)/phosphate (0.3%) solution or water, packaged in HiOx-MAP, stored 9 days at 1 °C, and then displayed for 7 days at 1 °C. The lactate/phosphate injection significantly improved color stability (higher a* values) of all three bovine muscles throughout display period. Accumulation of lipid oxidation determined by 2-thiobarbituric acid-reactive substances values was also decreased (P < 0.05) in the lactate/phosphate injection compared to the water treatment during storage and display periods. The objective tenderness values of longissimus and semimembranosus were also improved (P < 0.05) by the lactate/phosphate enhancement treatment compared to the water treatment based on star probe measurement. There were no significant differences found in desmin and troponin-T degradation, or oxidative cross-linking of myosin between treatments. The results suggest that lactate/phosphate enhancement has beneficial effects on color and lipid oxidation stability, and tenderness development of beef cuts under HiOx-MAP conditions.     

Shelf life and stability traits of traditionally and modified atmosphere packaged ground beef patties treated with lactic acid bacteria, rosemary oleoresin, or both prior to retail display

Previous research indicates that lactic acid bacteria (LAB) can inhibit pathogenic bacteria. This research evaluated effects of LAB inclusion on the shelf life of traditionally packaged ground beef patties; as well as the effects and possible interaction of LAB and rosemary oleoresin (RO) on the stability of high oxygen MAP ground beef during display. In both package types, trained and consumer evaluations indicated no effect (P > 0.05) of LAB on lean color and off-odor. Display affected trained and consumer sensory evaluations and indicated declined stability over time. Thiobarbituric acid values were lower for traditionally packaged ground beef with LAB (P < 0.05) and MAP ground beef with RO or RO and LAB (P < 0.05). Overall, LAB had no effect on the shelf life and stability of traditionally or high-oxygen MAP packaged ground beef patties. Therefore, utilization of LAB in ground beef to reduce pathogenic bacteria is viable without alteration of spoilage indicators.     

Lipids deposition,composition and oxidative stability of subcutaneous adipose tissue and Longissimusdorsi muscle in Guizhou mini-pig at different developmental stages

The aim of this study was to investigate the effect of developmental stage on lipids deposition, composition and oxidative stability of subcutaneous adipose tissue (SAT) and Longissimusdorsi muscle (LDM) in Guizhou mini-pig. Pigs were raised in the same condition, and SAT and LDM were sampled on 90 d, 180 d and 270 d. Lipids content decreased (P < 0.01) from 90 d to 180 d and increased (P < 0.01) from 180 d to 270 d in SAT and LDM. Neutral lipids in both tissues decreased (P < 0.01) from 90 d to 180 d and increased (P < 0.01) from 180 d to 270 d, while phospholipids content changed inversely during the three selected time points. Developmental times had great influence on fatty acids (FAs) composition of neutral lipids, phospholipids and free fatty acids (FFAs) except FAs composition of FFAs in SAT. Lipids oxidative stability in SAT and LDM both decreased between 90 d and 180 d (P < 0.05) and increased by 270 d (P < 0.05). In conclusion, due to the increased contents of unsaturated fatty acids and decreased oxidation stability, Guizhou or other mini-pigs slaughtered at an early age may have a negative effect on meat quality.     

Physicochemical and functional properties of chitosans affected by sun drying time during decoloration

The typical production of chitosan from crustacean shell consists of demineralization, deproteinization, decoloration, and deacetylation. Selected physicochemical and functional properties of chitosans as affected by various decoloration times (4, 5, 6, 7 or 8 h) using sun drying were evaluated. Moisture content (6.67-6.89 g/100 g), degree of deacetylation (81.91-82.73%), and color L^∗ value (78.32-79.43) of chitosans were not affected by sun drying time. However, color a^∗ and b^∗ values decreased when sun drying time was over 4 h. The viscosity of chitosan solution (0.5 g/100 mL acetic acid) decreased gradually with increasing sun drying time, with a more pronounced effect observed at 8 h of sun drying. There was no change in water-binding capacity (WBC) of chitosans decolorized by sun drying between 4 and 6 h; however, further increase in sun drying time from 6 to 7 or 8 h increased WBC of chitosans. DPPH radical scavenging activity of chitosans increased with increasing sun drying time. This study demonstrated that white-colored chitosans could be produced by an alternative decoloration step using sun drying for 4 h following the deacetylation step. However, increasing sun drying time to 7 h produced chitosan with increased WBC and DPPH radical scavenging activity.     

线粒体对肉色及其稳定性影响的研究进展

肉色是评价肉品品质最直观的指标,能够直接影响消费者的购买意愿。近40 年有较多学者对影响肉色及 其稳定性的因素进行了概述,但较少涉及线粒体对肉色及肉色稳定性的影响。线粒体与肌红蛋白的氧化还原状态密 切相关,它主要通过影响氧气消耗和高铁肌红蛋白还原来改变肉色及其稳定性,因此影响线粒体结构和功能的因素 也会影响肉色。本文对目前关于线粒体与肉色及其稳定性关系的研究进行综述,概括线粒体对肉色及其稳定性的直 接影响和基于线粒体影响肉色及其稳定性的因素,并阐述其影响机理。     

Mitochondrial Activity and Beef Muscle Color Stability

Concentration, oxygen consumption rate (OCR), oxygen consumption rate/g meat (OCRM) and metmyoglobin reducing activity (MRA) of muscle mitochondria were determined for beef longissimus dorsi and gluteus medius muscles of Holstein and crossbred steers which differed in color stability. OCR and OCRM decreased but no significant changes were observed in MRA during postmortem storage time. Significant effects of muscle and breed type on OCR, OCRM, and MRA were observed. Muscles and breeds of lower color stability had the highest levels of OCR, OCRM, and MRA. Differences in OCR of muscle mitochondria may be a contributing factor in the effects of muscle and breed on the rate of discoloration.     

Effects of soybean oil and oxidized soybean oil on the stability of β-carotene

The effects of 1.0%, 2.5%, and 5.0% purified soybean oil and thermally oxidized soybean oil on the stability of 100 ppm β-carotene as a fat-soluble vitamin A and singlet oxygen quencher in isooctane have been studied. The samples were stored under 1000, 2000, or 4000 lx at 20 °C for 2 days and at 50 °C for 16 days in the dark. The β-carotene was determined by high-performance liquid chromatography. The centrifugation and filtration of vegetable mixture, during sample preparation for β-carotene analysis by HPLC, decreased the coefficient of variation from 4.13% to 1.02%. The purified soybean oil and thermally oxidized soybean oil stabilized β-carotene in isooctane under light and in the dark at α = 0.05. The losses of β-carotene, with 1.0% purified oil, 1.0% thermally oxidized oil and without any oil during 48 h under light, were 11.2%, 80%, and 100%, respectively. 100 ppm TBHQ had a protective effect on the stability of β-carotene in isooctane at α = 0.05. The β-carotene stability decreased as the light intensity increased from 1000 to 2000 or 4000 lx at α = 0.05. The stability of vitamins in fruit and vegetable drinks enriched with fat-soluble vitamins and antioxidants during storage can be greatly improved by adding approximately 1.0% high quality non-oxidized soybean oil.