Yak Meat Research Articles

Protective characterization of low dose sodium nitrite on yak meat myoglobin in a hydroxy radical oxidation environment: Fourier Transform Infrared spectroscopy and laser Micro-Raman spectroscopy

The effect of NaNO2 in hydroxyl radical-mediated oxidative damage of yak meat myoglobin was investigated. Laser micro-Raman spectroscopy and Fourier Transform Infrared spectroscopy were used to assess protein (carbonyls, total sulfhydryl and Disulfide bonds) oxidation, atomic (or molecular) interactions and secondary structural changes. The addition of NaNO2 during the oxidation of myoglobin significantly reduced the content of carbonyl and disulfide bonds and protected the sulfhydryl groups from hydroxyl radical oxidation (P < 0.05). There was no significant difference in the secondary structure of myoglobin between the control group and the SN treatment group(P > 0.05). At the same time, NaNO2 had an inhibitory effect on the expansion of the hemoglobin center size and the transition of Fe from a low spin state to a high spin state caused by radical-oxidized. These findings suggest that NaNO2 has potential for treatment effects in a hydroxyl radical-oxidized myoglobin.

Fluorescence spectroscopy for accurate and rapid prediction of meat composition

The potential of fluorescence spectroscopy was assessed to study cow, goat, sheep and yak meat. Meat samples were taken from muscles, viz. Gluteus medius (GM), Longissimus dorsi (LD) and Semitendinosus (ST). The moisture, fat and protein content of meat samples were measured. The emission fluorescence spectra of tryptophan (305–500 nm), riboflavin (410–700 nm) and vitamin A (340–540) were recorded directly on meat samples at 290, 382 and 322 nm, respectively. Principal component analysis (PCA), partial least squares regression (PLSR) and partial least squares discriminant analysis (PLSDA) were applied to process the spectra obtained. Moisture content with R2=0.94, protein content with R2=0.86, and fat content with R2=0.91 were predicted from the fluorescence emission spectra. The PLSDA applied at 410–700 nm fluorescence spectra showed 100, 100, 94.4 and 92.6% of discrimination for cow, goat, sheep and yak meat, respectively. This study demonstrates that fluorescence spectroscopy has a potential for the accurate, non-destructive and rapid prediction of meat composition and it could replace existing traditional analytical methods.

Tenderization of Yak Meat by the Combination of Papain and High-Pressure Processing Treatments

The effects of papain and high-pressure processing (HPP), applied separately or in combination, on the tenderization of yak meat were studied regarding texture, water-holding capacity (WHC), cooking loss (CL), pH, and color. When papain was used alone, both the papain concentration level and treatment time could affect the tenderization. The maximal shear force (MSF) of yak meat was decreased by 46.85% and the WHC was increased by 9.93% when 80 U/mL papain was injected into yak meat and then incubated at 55 °C for 120 min. However, the color was significantly deteriorated. When the HPP treatment was performed alone, the MSF of yak meat displayed an initial decrease followed by an increase as the processing pressure or treatment time rose. Although an improved tenderizing effect was achieved at 250 MPa/15 min, leading to a MSF decline of 49.27% and a WHC increase of 10.50%, the meat turned white. Applying treatment sequences of an HPP and papain combination can significantly influence the tenderization effect. Optimal tenderization was obtained by the injection of papain (80 U/mL) and incubation at 55 °C for 30 min followed by HPP at 50 MPa/15 min (Pap → HPP). Results from this process indicated that the MSF of yak meat was decreased by 46.30% and 50.27%, respectively, compared to the separate applications of both HPP (50 MPa/15 min) and papain (80 U/mL, 30 min) treatments. Meanwhile, no significant color change was detected. The microstructure of yak meat was analyzed following the application of different treatments. Results suggest that the meat treated with Pap → HPP exhibited larger spacing and more damaged cells than untreated meat or the sample subjected to other treatments. These findings provided a possible explanation for the specific tenderization result when exposed to the combined treatments.

Мясо яков, как перспективное сырье для производства мясопродуктов

The present research features comparative data on the dynamics of meat production and consumption in the Republic of Buryatia. The analysis revealed stability and a slight increase in meat production and consumption per capita. The main sources of raw meat in Buryatia are cattle, sheep, and pigs, whereas goats, horses, and yaks make up a small part of farm animals in the region and serve as an additional source of valuable animal protein. The article contains a review of academic literature that showed a growing interest in yak meat studies, e.g. its nutritional value and use in meat products. The present research demonstrated that the nutritional and biological value of yak meat was similar to beef. However, yak meat proved to be tough, dark in color, and with a specific taste and smell. According to the experimental studies, the nutritional value of yak meat depends on the altitude of habitat. For instance, the higher the altitude, the larger the content of polyunsaturated fatty acids. The content of connective proteins, which can affect the consistency of the end product, was higher by 12.1% in yak meat than in beef. The experiment showed that the process of glycolysis in yak meat was 24 hours longer than in beef. The yak meat was tough due to the higher level of connective proteins, while its darker colour could be explained by the high content of myoglobin. These properties should be taken into account in the production of highquality meat products.

Effects of microwave heating on physicochemical properties, microstructure and volatile profiles of yak meat

ABSTRACT The effects of microwave cooking on the changes of physical properties, protein denaturation, microstructure and volatiles of yak meat were investigated. Various microwave power settings were used for cooking the yak longissimus meats, and SDS-PAGE, cooking loss, colour difference, shear force, microstructure and volatile flavour compounds of longissimus muscle were evaluated. Cooking losses (37.03–45.92%) and shear forces (257.20–315.57 N) in microwave heated meats were higher and lower, respectively, than these in boiled meats (p < .05). Cooking loss, a* values, and shear force significantly (p < .05) increased as the prolonged microwave cooking time, while L* value decreased (p < .05) and more muscle fibres fractured and contracted. High power (700 W; 100%) microwave cooked yak meat had higher L* values, but lower a* values and shear force than meats cooked at medium (560 W; 80%) or low (420 W; 60%) settings. Significant higher cooking loss and volatiles were found in medium power cooked meats compared to high and low power groups. The results suggested that microwave cooking could yield yak meat product with better texture and volatiles attributes but higher cooking loss and decolorization compared to conventional boiling cooking, and maybe an applicable processing method to obtain high quality yak meat products.

Comparison of Tenderness and Calpains Activity of Yak Meat in Different Ages During Postmortem Aging

Comparison of Tenderness and Calpains Activity of Yak Meat in Different Ages During Postmortem Aging

Growth Performance and Meat Quality Evaluations in Three-Way Cross Cattle Developed for the Tibetan Plateau and their Molecular Understanding by Integrative Omics Analysis.

Despite of favorable characteristics of high protein, low fat, and free-pollution, yak meat has intrinsically poor performance in tenderness and color, which is ever challenging yak sector. To this end, a three-way cross system was first developed for high quality beef of the Tibetan Plateau using Angus cattle ( Bos taurus) as terminal sire to mate with 1/2 yak (F1) generated from♂Qaidam cattle ( Bos taurus) × ♀yak ( Bos grunniens). The withers height, chest girth, and body weight of 1/4 yak (F2) were all great higher than that of yak and 1/2 yak ( P < 0.01), especially at later period, suggesting the faster growth rate of 1/4 yak. Also the dressing percentage was much better in 1/4 yak ( P < 0.01). Tenderness and meat color were both significantly improved in 1/4 yak with some unpleasant sacrifice of PUFAs, such as EPA and DHA, and meat protein, given the significantly lower shear force and higher L* ( P < 0.01). A total of 769 genes, including SREBF1, GHR, and FASN, the widely recognized causal genes of meat quality, were identified from 11947 differently expressed genes by the data integration of transcriptome, GWAS and QTL. These genes were significantly enriched for important pathway and GO terms, such as insulin signaling pathway, fatty acid biosynthesis, calcium signaling pathway, metabolic pathway, and cellular response to stress ( P < 0.01). And 12 promising candidates were exemplified with annotation of H3K4me3 data from divergent meat quality, such as OSTF1, NRAS1, and KCNJ11. Interestingly, 75 high-altitude adaptive candidate genes were also detected in the list. This study is a first step toward high quality beef of the Tibetan Plateau and provides useful information for their molecular understanding.

Identification of meat from yak and cattle using SNP markers with integrated allele-specific polymerase chain reaction–capillary electrophoresis method

Correct species identification is necessary for meat product quality assurance. Genetic markers are useful tools to accurately determine the animal source of meat products. To better protect yak meat and its products, ten single nucleotide polymorphism (SNP) loci from bovine meat-related genes and one positive control primer set were selected to discriminate meat sourced from yak or cattle. A multiplex allele-specific polymerase chain reaction and capillary electrophoresis method was employed for SNP genotyping. The samples were identified as from yak or cattle based on the number of amplicons. Yak samples generally produced one to three amplicon peaks, and the cattle samples yielded five or more peaks in the electropherogram. This method could be useful to distinguish yak meat from cattle beef, and would protect consumers and yak meat producers.

Effect of mitochondrial cytochrome c release and its redox state on the mitochondrial-dependent apoptotic cascade reaction and tenderization of yak meat during postmortem aging

We aim to investigate the effect of mitochondrial cytochrome c release and its redox state on the mitochondrial-dependent apoptotic pathway and yak meat tenderization during postmortem aging. Results indicated that the internal environment factors considerably decreased, whereas mitochondrial dysfunction increased in the early stage (0–72 h). Moreover, the release of mitochondrial cytochrome c into the cytosol, which was an apoptotic early event and the apoptosome elements in the cytoplasm changed remarkably with the increase of aging time. Meanwhile, N,N,N′,N′-tetramethylphenylene-1, 4-diamine (TMPD) inhibited the mitochondrial apoptotic process and postmortem meat tenderization by influencing the redox state of cytochrome c and apoptotic factors. These findings confirmed that the internal environment factors in the muscles provided essential conditions for mitochondrial cytochrome c, which activated the mitochondrial apoptotic pathway by forming apoptosome complexes. The reduction state of cytochrome c produced by TMPD plays a negative role in the activation of the mitochondrial apoptotic cascade reaction and meat tenderization during postmortem aging. We conclude that mitochondrial cytochrome c release and oxidized cytochrome c plays a significant role in yak meat tenderization by regulating the mitochondrial apoptotic pathway.

Using Mineral Elements to Authenticate the Geographical Origin of Yak Meat

Labeling systems for niche market food products is becoming increasingly important to address expectations. Yak meat is green product from natural extensive rangeland on Qinghai-Tibetan plateau. A trace technique is essential for consumers to know the origin of yak meat. In the current study, mineral fingerprints were investigated for their potential to classify yak meat according to geographical origin. The concentration of more than 50 mineral contents in 24 yak meat samples from three regions on Qinghai-Tibetan plateau were analyzed by ICP-MS. Multivariate statistical analyses were used to identify the most relevant indicators of origin. Seven elements (Na, As, Ni, Se, Rb, Cd and Ti) were selected for further routine analyses based on the significant origin differences (P<0.05). The three minerals (Se, Rb, Ti) were selected by statistics analysis and established discriminant model for yak meat traceability. Linear discriminate analysis gave an overall correct classification rate of 91.7% and cross-validation rate of 87.5%. These results demonstrate the usefulness of multi-element fingerprints as indicators for authenticating the geographical origin of yak meat.

Effects of Oxidative Cross-Linking of its Myofibrillar Protein on Texture during the Processing of Air-Dried Yak Meat

ObjectivesThis study aimed to examine the mechanism of cross-linking of myofibrillar protein and its influence on texture during the processing of air-dried yak meat.Materials and MethodsThe semimembranosus of 9 healthy and disease-free male yaks when they were 3 to 4-yr-old under natural grazing was selected for 20 kg, and these yaks are all from Gannan Prefecture, Gansu Province, China. The fascia and fat on the surface of the raw meat were removed and cut into strips with a cross-section of 2 cm × 2 cm in a freeze-dried room away from direct sunlight and naturally ventilated (room temperature –10 ∼ –15°C, relative humidity 50 ∼ 75%). The meat was hung on the wire, and the distance between adjacent 2 meats was maintained at 1 to 2 cm. Samples were collected during natural air-drying for 60 d. Carbonyl content, total thiol concentration, disulfide bond content, SDS-PAGE, dimeric tyrosine content, the surface hydrophobicity, histological characteristics and texture were measured, respectively. All of the experiments were conducted in triplicate for each sample, and the final results from the mean of 3 independent experimental replications. Dimeric tyrosine content, the surface hydrophobicity, histological characteristics and texture were measured, respectively. All of the experiments were conducted in triplicate for each sample, and the final results from the mean of 3 independent experimental replications.ResultsThe carbonyl content of raw meat is 2.63 nmol/mg, and increased by 6.35 nmol/mg in 60 d. With the increase of protein oxidation, the proportion of protein ɑ helices decreases while β sheets increase, and β-turns and random coils remain basically unchanged. The lost sulfhydryl group is cross-linked in the form of disulfide bonds, significant difference between 4 and 50 d (P < 0.05). Through SDS-PSGE experiments found that the cross-linking of myosin heavy chain formed macromolecules to stay on the top of the separation glue, fully verified this point (Fig. 6). The sensitive amino acid tyrosine was cross-linked by dimerization of dimeric tyrosine and changed significantly from 0 to 30 d (P < 0.05). Changes in the surface hydrophobicity of the protein can be obtained, and the aggregation of the protein is greater than that of the structure during processing from 4 to 60 d. These changes cause contraction of myofibrils in both the transverse and longitudinal directions, which in turn leads to hardness, cohesiveness, gumminess and chewiness were significantly increased (P < 0.05) in air-dried yak meat, springiness and resilience decreased significantly (P < 0.05) during processing.These changes cause contraction of myofibrils in both the transverse and longitudinal directions, which in turn leads to hardness, cohesiveness, gumminess and chewiness were significantly increased (P < 0.05) in air-dried yak meat, springiness and resilience decreased significantly (P < 0.05) during processing.Fig. 6.Myofibrillar protien SDS-PAGE of dried yak meat.ConclusionWith the increase of protein oxidation of yak meat during non-artificial freeze-drying, myofibrillin molecules crosslink and aggregate in the form of disulfide bond and dimeric tyrosine. These changes cause the muscle fibers to contract both horizontally and vertically, which in turn leads to hardness, cohesiveness, gumminess and chewiness were increased significantly, and result in decreased springiness and resilience ultimately.

Study on the effect of reactive oxygen species-mediated oxidative stress on the activation of mitochondrial apoptosis and the tenderness of yak meat

This study investigated the effect of reactive oxygen species-mediated oxidative stress on activation of mitochondrial apoptosis and tenderness of yak meat during postmortem ageing. Oxidative stress degree, Ca2+ levels, membrane permeability transition pore opening, mitochondrial membrane potential, apoptotic factors and the shear force were examined. Results showed that the ROS generated by H2O2 significantly increased mitochondrial oxidative stress by decreasing the activities of superoxide dismutase, catalase and glutathione peroxidase, and increasing lipid peroxidation. Furthermore, oxidative stress enhanced Ca2+ production and cytochrome c release, changed the levels of Bcl-2 family proteins and activated caspase-9 and -3 activities. Ultimately, oxidative stress increased the apoptosis rate and tenderness of yak meat. These observations confirmed that ROS-mediated oxidative stress participates in the activation of the apoptotic cascade reaction involving Ca2+ and Bcl-2 family proteins. The results further suggested that ROS-mediated oxidative stress plays a significant role in meat tenderization through the mitochondrial apoptotic pathway.

Effect of mitochondrial apoptotic activation through the mitochondrial membrane permeability transition pore on yak meat tenderness during postmortem aging

The effect of membrane permeability transition pore dependent mitochondrial apoptotic activation on yak meat tenderness was investigated. Results indicate that MPTP opening increased significantly and the mitochondrial membrane potential decreased markedly in the early aging process (P<0.05). Cytochrome c was released from the mitochondria to the cytoplasm via the MPTP in the early period. Meanwhile, the activation of procaspase-9 occurred earlier than that of procaspase-3. Cyclosporin A suppressed the MPTP opening, depolarization of the mitochondrial membrane potential, activities of caspase-9 and caspase-3, apoptosis rate, myofibril fragmentation index, reactive oxygen species generation, and Ca2+ levels. These results demonstrated that MPTP mediated the release of cytochrome c in the mitochondrial apoptotic pathway. Furthermore, yak meat tenderness was improved by mitochondrial apoptotic pathway during aging. MPTP opening may be influenced by the ROS generation and Ca2+ overloading in yak meat during postmortem aging.

The Correlation Research on Yak Meat Texture Profile Analysis (Tpa) And Freshness Parameters During Refrigerated Storage

The possible relationships of yak meat using PLSR between freshness and TPA parameters during cold storage were studied. Texture profile analysis (TPA) and freshness measurements of yak meat under the 4°C stored 0d, 2d, 4d, 6d, 8d, 10d and 12d were also performed. In addition, partial least squares regression analysis was carried out to find a correlation between the freshness data and TPA parameters. Significant (p<0.05) correlations among the freshness data and adhesiveness, cohesiveness, Springiness, chewiness and resilience were observed, Multivariate Regression analysis indicated that predictive regression equations of every parameters with all equations Fitting coefficient R2 greater than 0.800. Validation test R2 greater than 0.900, which showed a clear correlation between yak meat chemical changes and its texture properties during refrigeration. The results in this study could be used to explore the Texture profile analysis (TPA) important for using the TPA parameters rapidly evaluates yak meat freshness.

Development as Entangled Knot: The Case of the Slaughter Renunciation Movement in Tibet, China

A common conceptualization of development as a binary relationship between trustees and target groups is inadequate. This article proposes the metaphor of development as an entangled cultural knot, constituted by multiple power relations. It uses this concept to analyze a recent slaughter renunciation movement, in which some leading Tibetan Nyingma masters from Larung Gar have suggested that Tibetan herders give up selling their livestock to the slaughter market for religious reasons. The movement reflects an alternative form of development articulated by several leading Tibetan Buddhist teachers, particularly Khenpo Tsultrim Lodroe, yet it goes against the state project of developing the yak meat industry. This movement has been criticized not only by state officials, but also by secular Tibetan intellectuals, as well as by herders. This article argues that the complex relationships among Tibetan Nyingma teachers, state officials, Tibetan secularists, and herders; their shared and competing interests; and the apparently contradictory positions they take on various issues require a much more sophisticated conceptual tool than the simple dichotomous conceptualization of development.

Effect of electrical stimulation and hot boning on the eating quality of Gannan yak longissimus lumborum

The objective of this study was to evaluate the effects of electrical stimulation (ES) versus non-electrical stimulation (NES) and type of boning (hot versus cold) on the eating quality of Gannan yak longissimus lumborum. Eighteen Gannan yak bulls were randomly divided into two groups: ES and NES. Hot boning (HB) and cold boning (CB) were applied to the left and right side of the carcasses, respectively. All of the four treatments missed the “ideal” pH/temperature window. HB reduced the rate of pH decline, decreased meat tenderness and water holding capacity. ES increased the rate of pH decline and improved yak meat tenderness (P<0.05); however, ES explained only 1% of the variation in WBSF. HB and ES had no significant effects on cooking loss, L* or b* values of yak meat. Postmortem aging increased yak meat tenderness and improved meat color parameters. HB had negative effects on yak meat quality, while ES could not reverse these deleterious effects.

Using near infrared spectroscopy to predict the physical traits of Bos grunniens meat

The purpose of the current study was to evaluate the use of near infrared spectroscopy to predict the physical traits of yak (Bos grunniens) meat. Near infrared spectra data of M. longissimus thoracis from 162 yaks were collected, as well as physical traits data. Prediction models of physical traits using near infrared spectroscopy were established through partial least squares regression (PLSR) combined with mathematical pretreatments such as orthogonal signal corrections (OSC) and detrending corrections (DT). The coefficients of determination of calibration (RC2) of prediction models were higher than 0.6 except WBSF. The ratio performance deviation for a* and b* values and their derived values SI and HA exceeded 2.0, which are suitable for screening. Through modeling separately for steers and heifers, we found that prediction ability for cooking loss would be increased but for b* would be decreased. Conclusively, near infrared spectroscopy is useful for predicting physical traits of yak meat and could be a potential tool for monitoring beef quality of the yak.

Post-mortem oxidative stability of three yak (Bos grunniens) muscles as influenced by animal age

The influence of animal age and muscle source on the oxidative stability of yak steaks was examined. Longissimus thoracis (LT) muscles from yaks of different age groups (0.5, 1.5, 2.5, and 3.5years), and three muscle sources of LT, Psoas major (PM), and Biceps femoris (BF) from yaks of 0.5, 1.5, and 2.5years, were evaluated for metmyoglobin content, activity of antioxidant enzymes, and antioxidant capacity. Oxidative stability was influenced (P<0.05) by muscle source and animal age. LT steaks from 0.5, 1.5, and 2.5year old yaks exhibited lower (P<0.05) metmyoglobin content than their PM and BF counterparts. Furthermore, LT steaks from 3.5year old yaks demonstrated lower (P<0.05) metmyoglobin content and greater (P<0.05) activities of antioxidant enzymes than LT steaks from other age groups. These results indicated the necessity to develop muscle- and age-specific processing strategies to improve color and oxidative stability of yak meat.

Color stability and antioxidant capacity of yak meat as affected by feeding with pasture or grain

Chen, C., Han, L., Yu, Q.-L. and Li, R.-R. 2015. Color stability and antioxidant capacity of yak meat as affected by feeding with pasture or grain. Can. J. Anim. Sci. 95: 189–195. The objective of the present study was to analyze the effect of pasture or grain on color stability and antioxidant capacity of M. longissimus lumborum (LL) from pasture-fed (PF) or grain-fed (GF) yaks. The color stability and metmyoglobin percentage (MetMb%) were determined during 9 d of aerobic refrigerated storage. The antioxidant capacity was estimated by the total phenolics content, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP). Compared with the GF group, the LL from the PF group showed significantly (P&lt;0.05) higher redness (a* values), with lower decline rate in a* values (P&lt;0.05) over 1 to 7 d of refrigerated storage. The LL from the PF group had a significantly (P&lt;0.05) lower metmyoglobin accumulation rate. At the end of storage, the muscle's MetMb% of the PF and GF group were 46.33 and 56.66%, respectively. The PF group showed significantly higher total phenolics content (+23.94%; P&lt;0.05) in muscles, resulting in greater TEAC and FRAP, which were 24.81 and 3.99% higher than the GF group (P&lt;0.05), respectively. In conclusion, the pasture enhanced antioxidant capacity of yak meat and contributed to improve the meat color stability.

Chinese yak and yellow cattle exhibit considerable differences in tissue content of squalene, tocopherol, and fatty acids

Bioactive components in five tisues (longissimus muscle (LSM), biceps femoris muscle (BFM), liver (LV), subcutaneous adipose tissue (SAT), and abdominal adipose tissue (AAT)) of yak in Tibet and yellow cattle in Hubei were investigated. Yak was significantly higher (p&lt;0.01) than yellow cattle in the squalene content of lipids of BFM (59.82/19.07 mg/100g), LSM (20.99/7.81 mg/100g) and LV (6.94/2.67 mg/100g), respectively, but not in SAT and AAT (p&gt;0.05). Yak was also significantly higher (p&lt;0.05) than yellow cattle in the total tocopherol content. Additionally, yak hepatic lipids showed the highest content of saturated fatty acids (58.11%) and polyunsaturated fatty acids (PUFA, 25.81%) and the lowest content of monounsaturated fatty acids (MUFA, 16.08%), while yellow cattle AAT had the highest content of MUFA (47.54%) and the lowest content of PUFA (2.36%). The considerable differences between the two in composition suggest that the five tissues of yak are potential sources of bioactive components and essential fatty acids for humans.Practical applications: The results from the analysis of the contents of squalene, tocopherols, total lipids，moisture, ash, and pH and fatty acid profile in the studied tissues of Tibet yak and Hubei yellow cattle provide useful information for developing functional foods using yak meat or other tissues as materials.Comparison of squalene and total tocopherol contents in different tissues of yak and yellow cattle.