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A study was carried out to investigate the effects of ionic strength and temperature on the interaction between fish myoglobin and myofibriliar proteins in a model system. Binding of myoglobin to natural actomyosin (NAM) was observed and it increased when ionic strength was increased at concentrations of 0.6 M KCL and with increases in temperature from 4 to 25 degree Celsius.

Research investigating the amount of aldehyde lipids found in beef and in vitro is presented. Particular attention is given to analyses of processes of lipid oxidation and proteins found in ground beef, as well as to detecting concentrations of tocopherol.

Research describing the formation of yellow pigment in thiobarbituric acid analysis of freeze dried meat is presented. The effects of fluorescence and different antioxidants are also evaluated.

There is an antioxidant effect of canthaxanthin (CX) in phosphatidylcholine liposomes in minced flesh from rainbow trout, according to research seeking to identify an effects of CX as a potential antioxidant in a liposome model system and in the flesh of CX-supplemented rainbow trout. It was found that CX concentration of minced trout muscle declines during six days of refrigerated storage. If fish are received by a supermarket or consumer with some initial oxidation, then CX may act as an effective antioxidant.

Hereford-Angus crossbred heifers were fed a cottonseed meal-based diet containing gossypol (14 mg free gossypol[center dot]kg body [wt.sup.-1][center dot][d.sup.-1]; CSM), a soybean meal-based diet (SBM), or [Alpha]-tocopherol-supplemented diets (4,036 IU vitamin E[center dot][heifer.sup.-1][center dot][d.sup.-1] for 90 d; CSM+E and SBM+E). The effects of diet on color stability and aerobic metmyoglobin reducing ability of beef longissimus lumborum (LL) and psoas major (PM) were evaluated. The CSM containing gossypol did not affect [Alpha]-tocopherol concentration, [a.sup.*] value, or hue angle value of beef muscles obtained from control or vitamin E-supplemented cattle compared to their SBM counterparts. Vitamin E supplementation increased endogenous [Alpha]-tocopherol concentrations and color stability in LL and PM muscles compared with controls from either diet (P < .05). In the aerobic metmyoglobin reducing ability study, LL and PM muscles were stored in 1%[O.sub.2]:99%[N.sub.2] (a pigment-oxidizing atmosphere) for 48 h and subsequently stored aerobically for an additional 48 h. Within the LL, [Alpha]-tocopherol supplementation delayed metmyoglobin formation in LL exposed to 1%[O.sub.2] (P < .05). Within the PM, no differences in metmyoglobin formation were found between controls and vitamin E treatments in SBM or CSM diets. Relative aerobic metmyoglobin reduction was the same (P > .05) in LL and PM muscles within SBM or CSM diets for control and vitamin E treatments. [Alpha]-Tocopherol did not seem to affect metmyoglobin aerobic reducing ability in LL and PM muscles. Key Words: Tocopherols, Gossypol, Meat Characteristics

Dietary supplementation of livestock with vitamin E results in improved quality of meat subsequently obtained from these animals. The effect is especially noteworthy in cattle, in which the primary effects are delayed discoloration and lipid oxidation. A threshold level of [Alpha]-tocopherol in muscle ensures a detectable effect; dietary strategies for attaining this threshold must consider tocopherol status of cattle arriving at the feedyard and duration and level of supplementation. The [Alpha]-tocopherol concentration in muscle must be determined before proper interpretation of experimental results can be made. Muscles vary in their color stability, and this relative difference is not changed by vitamin E supplementation. Several in vitro models have been used to characterize the interaction between .tocopherol, lipid oxidation, and oxymyoglobin oxidation. [Alpha]-Tocopherol seems to exert its color-stabilizing effect by indirectly delaying oxymyoglobin oxidation via direct inhibition of lipid oxidation. However, recent results demonstrating a protective effect of [Alpha]-tocopherol toward oxymyoglobin in low-oxygen atmospheres indicate that additional mechanisms may exist. A better understanding of the fundamental bases for protection of water-soluble myoglobin by lipid-soluble [Alpha]-tocopherol is needed to optimize this beneficial effect. Key Words: Vitamin E, Tocopherols, Oxidation, Meat Quality

The shelf life of meat is reduced by the growth of spoilage bacteria and can cause manufacturers major economic losses. Determining the total bacterial load of meat by the standard plate count method takes 48 hours and a faster method is required. A new study investigates whether fluorescein diacetate hydrolysis and resazurin reduction can be used as rapid predictors of spoilage bacterial load on stored fresh and frozen meat. It is shown that such methods could be rapid alternatives to the plate count method.

Vitamin E supplementation seems to help beef color stability as sensory panelists gave vitamine E-supplemented beef steaks higher scores. Meat spoilage is not affected by such supplementation. No differences in bacterial load appeared during storage of the 3 vitamin E treated groups. Meat maintained at 25 degrees celsius for 24 hours has increased metmyoglobin formation. Vitamin E supplementation does seem to mitigate the adverse effect of such temperature abuse.

Percentage of lean, fat, and bone were determined in 18 bob veal (BV) and 28 special-fed veal (SFV) carcasses. Carcasses were subjected to a set of visual conformation scores and a variety of physical measurements. No significant differences were found regarding carcass percentage of lean, fat, and bone within the three BV weight groups (P [is greater than] .05). On average, SFV were 12% fatter than BV and did not have a greater percentage of lean (P [is greater than] .05), except for SFV carcasses weighing 88.2 to 97.7 kg. Bob veal had less fat (internal, external, and intermuscular) and a higher bone percentage than SFV (P [is less than] .05). The round and shoulder primals had the greatest proportion of lean in both the BV and SFV carcasses. Bob veal carcasses had an average conformation score of average Good and SFV carcasses had an average conformation score of average Choice. In addition, a parsimonious subset of variables was identified for predicting total percentage of lean (TPLEAN) for both BV and SFV separately, using 'stepwise' regression model building procedures. For BV, all four identified predictor variables were subjective conformation scores (i.e., muscling, appearance, leg thickness, loin-back plumpness) (R = .73, P [is less than] .03). For SFV, four predictor variables were also identified: kidney and pelvic fat, fat thickness, carcass length, and lateral thickness (R = .61, P [is less than] .03). Although both regression equations were significant predictors of TPLEAN, confidence limits for predicting future TPLEAN value were wide relative to the variation in the actual TPLEAN values. Thus, the practical utility of the regression equations is limited.

An oxymyoglobin (OxyMb)-liposome model facilitated the characterization of the antioxidant potential of alpha-tocopherol and pro- or antioxidant activities of ascorbate. These studies were aimed at identifying the correlation between oxidation of oxymyoglobin and phospholipid, and concentration of alpha-tocophorol and ascorbate. The two antioxidants prolonged the oxidation time of OxyMb and phospholipid concentrations of 14 micromoles for ascorbate optimized their antioxidant activities, thus rendering an optimal delay in the oxidation time.

The expression of heat shock protein with a molecular weight of 70 kDa (Hsp 70) in porcine tissue and its potential relationship to stress susceptibility was studied. Twelve pigs, four of each genotype (NN, Nn, and nn) for halothane sensitivity were slaughtered. At 45 min postmortem, several tissues (liver, kidney, spleen, skeletal and cardiac muscle, and adrenal gland) were sampled for Hsp 70 analysis. At 24 h postmortem, longissimus and semimembranosus muscle were sampled for assessment of meat quality. Water-holding and water-binding capacity, color, and protein denaturation of samples from halothane-positive animals indicated that these animals had been stressed. Homozygous nn pigs demonstrated a lower |pH.sub.45~ and higher L-value at 48 h than their NN and Nn counterparts (P |is less than~ .05). The longissimus, but not semimembranosus, muscle of nn pigs demonstrated lower water-holding capacity and greater protein denaturation than that of NN or Nn pigs (P |is less than~ .05). The water-binding capacity of both longissimus and semimembranosus was less in nn than in Nn or NN pork (P |is less than~ .05). Using one-dimensional PAGE and Western blotting, Hsp 70 was shown to be present in all tissues examined. With two-dimensional PAGE followed by blotting, the presence of the cognate and inducible form of Hsp 70 was investigated. There did not seem to be a relationship between stress (based on meat quality) and expression of either form of Hsp 70.

A comparative study of the nutritional content and storage-life of red and white veal is presented. Results indicate that both veal varieties are similar in many nutritional aspects, except that white veal has a lower iron content than the red veal variety which contained a lower cholesterol level but higher iron and zinc concentrations. However, red veal discolored faster than its white counterpart, indicative of its susceptibility to lipid oxidation.

An analysis of interactions between fish myoglobin (Mb) and myofibrillar proteins as a function of time in an Mb-natural actomyosin (NAM) model at refrigerated temperature (4 degree Celsius) is described. It is observed that the interaction between dish Mb and myofibrillar proteins were more prominent with greater storage time and formation of high-molecular-weight aggregates also became more with time and also that disulfide bonds were not involved in Mb-NAM interactions.

The relative proportions of myoglobin (Mb) redox forms in aqueous solution was estimated using modified Krzywicki's equations as the original one gave negative values for some redox forms. The new equations demonstrated improved performance in decreasing the occurrence and magnitude of negative values and in estimating total Mb, when compared with Krzywicki' original equations.

Myoglobin(MB) is the major oxygen storage and transport heme protein that gives meat its red color. MB is studied for several animal species and there are slight species differences in the molecular properties of this protein.

Research has been conducted on myoglobin. The covalent binding of 4-hydroxy-2-nonenal to bovine myoglobin and its role in redox stability have been investigated, and the results are reported.

It has been approximately 10 years since the Government Accountability Office (GAO) published its report to Congress entitled, FDA Should Strengthen Its Oversight of Food Ingredients Determined to be Generally Recognized as Safe (GRAS) , which strongly criticized FDA noting that its "oversight process does not help ensure the safety of all new GRAS determinations." Congress requested GAO to undertake this audit as a result of concerns that GRAS substances added to foods did not require FDA approval. Since 2010, FDA has addressed only a few of the criticisms regarding its process for establishing a food substance as GRAS. However, several of the most important GAO recommendations remain unaddressed, and most critically, FDA has chosen to remain uninformed about food substances self-determined as GRAS by manufacturers. In its 2016 final rule Substances Generally Recognized as Safe, FDA did not take the opportunity to include a provision for creation of a master list of all GRAS chemicals used in food, nor did the FDA request the authority to do so from Congress. FDA cannot fulfill its statutory obligation for ensuring the chemical safety of the U.S. food supply if it does not know which substances, in which quantities, have been added to foods.

Appearance is an important sensory property that significantly influences consumers' perceptions of fresh meat quality. Failure to meet consumer expectations can lead to rejection of meat products, concomitant loss in value, and potential production of organic waste. Immediately after animal harvest, skeletal muscle metabolism changes from aerobic to anaerobic. However, anoxic post-mortem muscle is biochemically active, and biomolecular interaction between myoglobin, mitochondria, metabolites, and lipid oxidation determines meat color. This review examines how metabolites and mitochondrial activity can influence myoglobin oxygenation and metmyoglobin reducing activity. Further, the review highlights recent research that has examined myoglobin redox dynamics, sarcoplasmic metabolite changes, and/or post-mortem biochemistry.

Proof-of-principle for large-scale engineering of edible muscle tissue, in vitro, was established with the product's introduction in 2013. Subsequent research and commentary on the potential for cell-based meat to be a viable food option and potential alternative to conventional meat have been significant. While some of this has focused on the biology and engineering required to optimize the manufacturing process, a majority of debate has focused on cultural, environmental, and regulatory considerations. Animal scientists and others with expertise in muscle and cell biology, physiology, and meat science have contributed to the knowledge base that has made cell-based meat possible and will continue to have a role in the future of the new product. Importantly, the successful introduction of cell-based meat that looks and tastes like conventional meat at a comparable price has the potential to displace and/or complement conventional meat in the marketplace., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

As a pro-oxidant, myoglobin (Mb) can induce lipid oxidation in meat. In this study, Fourier-transform infrared spectroscopy (FTIR), circular dichroism (CD), fluorescence spectroscopy, UV-vis spectrophotometry, and fluorescence microscopy were used to evaluate the impact of Maillard reaction products (MRPs) formed from glucose and lysine on the oxidative stability of carp Mb. MRPs were found to inhibit the auto-oxidation of Mb, reducing MetMb production by 8.45%. The static quenching of fluorescence indicated that MRPs interacted with Mb through hydrogen bonding and van der Waals forces, thereby enhancing the α-helical content by 11.57% and reducing the random coil content by 2.72%. The enhanced stability of this advanced structure helps to minimize the exposure of amino acid in the side chain and prevent the formation of MetMb. Fluorescence microscopy showed that MRPs reduce porphyrin ring degradation, consequently decreasing heme iron release. It is evident that MRPs play a crucial role in maintaining Mb structure stability and inhibiting its oxidation., (© 2024 Institute of Food Technologists.)

BSTRACT The present study characterized oxymyoglobin (OxyMb) and lipid oxidation in yellowfin tuna, and determined the influence of various aldehydes on tuna OxyMb stability in vitro. Surface metmyoglobin accumulation and lipid oxidation increased in tuna steaks with time ( P < 0.05). In both tuna steaks and patties, a* values decreased ( P < 0.05) and hue angle increased following 6 d storage ( P < 0.05). Sensory evaluation demonstrated increased discoloration and decreased odor acceptability in refrigerated steaks and patties over time (P < 0.05). Hexanal, hexenal, and 4-hydroxynonenal enhanced OxyMb oxidation relative to controls in vitro (P < 0.05). These results indicate a relationship between myoglobin and lipid oxidation in tuna, and that aldehydes known to be produced during lipid oxidation can accelerate tuna OxyMb oxidation in vitro. Keywords: yellowfin tuna, oxymyoglobin, lipid oxidation, discoloration, aldehydes [ABSTRACT FROM AUTHOR]

Studies the effects of alpha-tocopherol and/or ascorbate upon oxymyoglobin and lipid oxidation. Delay of oxidations by increased concentrations of alpha-tocopherol and alpha-tocopherol/ascorbate relative to controls; Preoxidant effect of ascorbate toward lipid oxidation.

Lipid oxidation significantly contributes to muscle deterioration, with heme protein oxidation playing a crucial role in this process. This study investigated the inhibition of heme protein oxidation by Maillard reaction products (MRPs) using a washed muscle model combining washed carp with myoglobin (Mb). Protein oxidation products, protein texture, and lipid oxidation levels were assessed. Results showed that metmyoglobin (MetMb) is a primary driver of lipid oxidation in meat, likely due to Mb oxidation, exposing hydrophobic groups that bind to lipids. MRPs at concentrations of 0.5% and 1% effectively inhibited Mb oxidation. Specifically, treatment with 1% MRPs reduced MetMb formation by 15.38%, protein carbonyl content by 6.53%, hydroxyl radical content by 20.37%, protein aggregation by 40.81%, and particle size by 36.95% during later storage stages, thereby preserving Mb stability. In the Mb-mediated oxidation model, 1% MRPs inhibited the formation of primary and secondary oxidative metabolites by 59.47% and 68.19%, respectively, while maintaining muscle tissue texture integrity. PRACTICAL APPLICATION: The antioxidation of Maillard reaction products (MRPs) improves the stability of common carp. By inhibiting the autoxidation of myoglobin and lipid, MRPs help preserve the texture and color of fish muscle while extending its shelf life. This study provides a valuable reference for effectively controlling lipid oxidation in refrigerated fish products and enhancing their overall quality., (© 2024 Institute of Food Technologists.)

The influence of storage atmosphere on the color development and myoglobin (Mb) redox state of beef was investigated. Beef samples were packaged in 6 different atmospheres including different degrees of vacuum, levels of oxygen, nitrogen, and a mixture with 20% CO 2 and stored at 2°C for 14 days. Over this time, color and reflection of the packaged samples were measured. The used method allows quick, easy, and non-invasive measurement of the packaged samples, without using time consuming chemical assays. The method could be implemented in beef production lines, with potential for automatization. The data was used to illustrate the L*a*b* values for insights regarding qualitative color changes. Quantitative color changes were analyzed by calculation of color difference ΔE 2000 . Additionally, the relative levels of the deoxymyoglobin (DMb), oxymyoglobin (OMb) and metmyoglobin (MMb) were calculated from reflection spectra. The most important findings are: there is a strong correlation (r sp  = 0.80 to 0.99 with one exception at r sp  = 0.69 (high vacuum), p ≤ 0.05) between a* values and relative OMb levels. Storage atmospheres containing high oxygen concentrations lead to an attractive meat color, but a decreased overall color and Mb stability (ΔE = 5.02 (synthetic air) and ΔE = 2.23 (high oxygen) after 14 days of storage). Vacuum packaged samples are most stable in regards of color and Mb stability (ΔE = 1.79 (high vacuum) and ΔE = 1.63 (low vacuum) after 14 days of storage), but lack in the vibrant red color desired for sale. The experiments showed that color measurement can be a fast, non-invasive marker for meat quality. PRACTICAL APPLICATION: In this research article, six different storage atmospheres are compared regarding their influence on color stability and color quality of beef during storage in packaging. The results suggest which atmospheres to use in various sales-related scenarios. The method described can easily be applied in the meat industry to quickly monitor changes during storage and wet-aging without damaging the meat or opening the meat packages., (© 2024 The Author(s). Journal of Food Science published by Wiley Periodicals LLC on behalf of Institute of Food Technologists.)

The article discusses a study which modified Krzywicki's equations by using wavelength maxima at 503, 557, and 582 nanometer (nm), representative for metmyoglobin, deoxymyoglobin, and oxymyoglobin, respectively to determine the relative proportions of myoglobin (Mb) redox forms in aqueous meat extracts. Compared with the original Krzywicki equations, the new equations demonstrated improved performance in decreasing the occurrence and magnitude of negative values and in estimating total Mb.

BSTRACT: Ground beef patties (15% fat) were freeze-dried to different aw endpoints and stored at 25°C or 49°C. Water activity, total moisture (%), lipid oxidation (TBARS@450nm), and protein solubility were evaluated. TBARS @450nm was favored at 49°C, but not at 25°C except at high aw range (p < 0.05), whereas protein solubility was greater at 25°C than 49°C (p < 0.05). TBARS@450nm values at 49°C were generally greatest at low aw range (p > 0.05). Protein solubility was lowest at medium aw at 49°C (p < 0.05), while at 25°C low aw protected protein solubility better than other low or high aw values. [ABSTRACT FROM AUTHOR]

The compound 4-hydroxy-2-nonenal (HNE) dissolved in water was examined to remove potential effects of using ethanol to solubilize the aldehyde such as altering protein structure or redox properties of myoglobin (Mb). HNE became covalently bound to sperm whale Mb at up to five sites based on ESI-MS analysis. Adducted Mb promoted lipid oxidation in washed muscle more effectively than non-adducted Mb. Alkylation of P88H/Q152HMb with HNE accelerated metMb formation and subsequent lipid oxidation. P88H/Q152HMb exposed to HNE enhanced lipid oxidation compared to wild-type Mb exposed to HNE. Results using H97A Mb suggested that the combination of HNE and low hemin affinity facilitated rapid decomposition of preformed lipid hydroperoxides to secondary lipid oxidation products. HNE and HHE (4-hydroxy-2-hexenal) facilitated Mb-mediated lipid oxidation similarly. The potential mechanisms by which Mb binding of α,β-unsaturated aldehydes affect Mb oxidation and the onset of lipid oxidation are discussed., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Presents information on a study which examined the effects of canthaxanthin (CX) as a potential antioxidant in a liposome model system and in the flesh of CX-supplemented rainbow trout. Measurement of lipid oxidation in liposomes; Materials and methods of the study; Results and discussion; Conclusions.

Provides information on a study which evaluated the effects of cottonseed meal-based (CSM) diet containing gossypol and soybean meal-based diet (SBM) on meat color stability and aerobic metmyoglobin reducing ability of beef longissimus lumborum and psoas major muscles. Materials and methods; Concentration of ...-tocopherol; Overall metmyoglobin reduction; Conclusions.