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BACKGROUND RESULTS CONCLUSION This study aimed to explore how interactions between reactive oxygen species (ROS) and reactive nitrogen species (RNS) affect oxidative properties, nitrosative properties, and myofibrillar protein degradation during postmortem aging of yak meat.Yak longissimus dorsi was incubated with saline, ROS activator (H2O2)/inhibitor N‐Acetyl‐L‐cysteine (NAC) and RNS activator S‐Nitrosoglutathione (GSNO)/inhibitor L‐NAME hydrochloride (L‐NAME) combined treatments at 4 °C for 12, 24, 72, 120, and 168 h. The results indicated that regardless of whether RNS was activated or inhibited, activated ROS played a dominant role in myofibrillar protein degradation by oxidative modification to increase carbonyl content, disulfide bonds, surface hydrophobicity, and dimerized tyrosine while decreasing sulfhydryl content, thereby degrading nebulin, titin, troponin‐t and desmin. Notably, the Warner–Bratzler shear force (WBSF) of the H2O2 + L‐NAME group was the smallest, whereas that of the NAC + GSNO group was smaller than that of the NAC + L‐NAME group.These findings provide new insights into meat tenderization patterns through the interaction between ROS and RNS. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

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Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to investigate the effect of curing time on the edible quality and oxidative characteristics of compound low-sodium yak meat products, in this experiment, complex low-sodium yak meat was selected to investigate the effects of curing time (12, 18, 24, 30 and 36 h) on the edible quality and oxidative characteristics. The results showed that prolonging the curing time significantly reduced the cooking loss (P

To investigate the changes in the quality of yak meat at different dry aging times (7, 14, 21, 28 and 35 d), in this study, sensory evaluation, texture analysis, and GC-IMS were employed to investigate the changes in texture and flavor of yak meat during different dry aging periods. Additionally, PLS-DA was utilized to identify the characteristic flavor compounds. The results showed that the dry aged 35 days sample exhibited the highest comprehensive score, with intact soft tissue structure and a favorable overall acceptability of aroma. The dry aging time had significant effects on the hardness, chewability, and adhesivity of yak meat (P

This study aimed to examine the impact of different low-sodium formulations on the quality and oxidative properties of yak meat products. Yak foreleg meat was utilized as the primary raw material, and various proportions of potassium chloride (KCl) and sodium pyrophosphate were incorporated to partially replace sodium chloride (NaCl) during the marination process. The objective was to assess the effects of these low-sodium composite salts on yield, edible quality, lipid oxidation, and protein oxidation of yak meat in sauce, while also determining the optimal ratio of composite substitutes for sodium salts. The findings revealed that an increasing substitution of sodium pyrophosphate and KCl resulted in a significant increase in product yield (P

In order to improve the effect of microwave thawing on yak meat quality, this paper mainly adopted four different intermittent microwave thawing methods to determine and analyze the indicator changes of the nutritional quality of yak meat and peroxide-value (POV), superoxide dismutase (SOD), total volatile base nitrogen (TVB-N), thiobarbituric acid reactants (TBARS). The results showed that the thawing loss of yak meat in mode 1 (heat 10 s and stop10 s as a cycle) was less, higher protein and fat content among the several thawing methods, and the hardness, viscosity and chewiness of yak meat were the smallest, which dates were 2612.115 g, 1771.18 N and 878.63 mJ respectively, with a shear force of 69.59 N and pH of 5.9. At the same time, the freshness preservation effect was better. Compared with room temperature thawing, the mode 1 reduced the degree of fat oxidation of yak meat, its POV and TBARS were 9.45 mmol/kg and 0.36 mg/kg respectively. But there was no significant data difference between SOD activity and TVB-N and other thawing methods (P>0.05). Therefore, choosing the mode 1 to thaw, which could greatly reduce the damage of yak meat caused by thawing in terms of basic quality.

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This study aimed to investigate the effects of nitric oxide (NO)-mediated hypoxia-inducible factor-1α (HIF-1α) on the glycolysis and tenderness of postmortem yak muscle and its regulatory mechanism. In this study, Yak Longissimus dorsi was injected with 0.9% saline (control), 200 μmol/L S-nitrosoglutathione (GSNO), 200 μmol/L GSNO + 100 μmol/L YC-1 (HIF-1α inhibitor) or 200 μmol/L GSNO + 50 μmol/L PD98059 and aged, and NO level, HIF-1α, mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway activation, glycolysis-related enzyme activities, and shear force of muscle were analyzed at different aging time points (3, 6, 9, 12, 24 and 72 h). The results revealed that NO levels in the GSNO group were significantly higher than those in the control group during 3–72 h (P < 0.05), reaching a peak at 6 h. ERK1/2 and p-ERK1/2 expression levels were higher in the GSNO group than the control and GSNO + PD98059 groups during 3–72 h (P < 0.05), reaching a peak at 24 h. HIF-1α expression level in the GSNO group was significantly higher than that in the control and GSNO + YC-1 groups (P < 0.05), peaking at 12 h. Hexokinase (HK), pyruvate kinase (PK) and lactate dehydrogenase (LDH) in the GSNO group reached their maximum values at 9, 12 and 12 h, respectively (P < 0.05) and were significantly higher than those in the control group; at 3, 12 and 72 h, the glycolytic potential in the GSNO group was significantly higher than that in the two other groups (P < 0.05); at 6, 9 and 72 h, the pH in the GSNO group was significantly lower than that in the other groups (P < 0.05). In addition, shear force and hematoxylin and eosin (HE) staining were used to assess the tenderness of yak meat. Shear force, myofiber cross-sectional area and diameter were lower and the space between myofibers was higher in the GSNO group than in the two other groups. In conclusion, during the early period of postmortem aging, NO mediates the MAPK/ERK signaling pathway, thereby activating HIF-1α expression and upregulating HK, PK and LDH activity, accelerating the rate of glycolysis of and reducing pH, and ultimately improving the tenderness of yak meat. The results of this study may serve as a potential regulatory mechanism for regulating the tenderness of yak meat and provide a theoretical basis for improving the theoretical system of glycolysis and tenderness during postmortem aging.

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Simple Summary: Yaks are a major economic source for people in the Tibetan Plateau region. Yaks are rich in nutrients, but their low fat content is not conducive to the large-scale promotion of yak meat, so the study of the mechanism of yak lipid deposition is beneficial to the marketing of yak meat. In this paper, the results of transcriptome sequencing analysis of yak liver showed that it could be determined that the expression levels of genes associated with partial lipid deposition were significantly up-regulated during yak fattening. In addition, this study found that the tenderness of yak meat improved during this process. Fattening significantly affects fat deposition in yaks, which may be realized through its effects on lipid metabolic pathways. Therefore, studying the mechanism of lipid deposition in yaks and fattening yaks will improve the quality of yak meat. Yak meat is nutritionally superior to beef cattle but has a low fat content and is slow-growing. The liver plays a crucial role in lipid metabolism, and in order to determine whether different feeding modes affect lipid metabolism in yaks and how it is regulated, we employed RNA sequencing (RNA-seq) technology to analyze the genome-wide differential gene expression in the liver of yaks maintained under different raising systems. A total of 1663 differentially expressed genes (DEGs) were identified (|log2FC| ≥ 0 and p-value ≤ 0.05), including 698 down-regulated and 965 up-regulated genes. According to gene ontology (GO) and KEGG enrichment analyses, these DEGs were significantly enriched in 13 GO terms and 26 pathways (p < 0.05). Some DEGs were enriched in fatty acid degradation, PPAR, PI3K-Akt, and ECM receptor pathways, which are associated with lipid metabolism. A total of 16 genes are well known to be related to lipid metabolism (e.g., APOA1, FABP1, EHHADH, FADS2, SLC27A5, ACADM, CPT1B, ACOX2, HMGCS2, PLIN5, ACAA1, IGF1, FGFR4, ALDH9A1, ECHS1, LAMA2). A total of 11 of the above genes were significantly enriched in the PPAR signaling pathway. The reliability of the transcriptomic data was verified using qRT-PCR. Our findings provide new insights into the mechanisms regulating yak meat quality. It shows that fattening improves the expression of genes that regulate lipid deposition in yaks and enhances meat quality. This finding will contribute to a better understanding of the various factors that determine yak meat quality and help develop strategies to improve yield and quality. [ABSTRACT FROM AUTHOR]

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Objective: Analyze the differences in mineral element content in yak meat from Leiwuqi County, Changdu City, Tibet. Methods: This study focused on 431 yak meat samples from Leiwuqi County, Xizangchang City, including (Kamado Township, Leiwuqi Township, Yiri Township, Changmaoling Township, Gangse Township, Sangdo Township, Binda Township, Shangka Township, Jiasangka Township, Jiduo Township). The contents of K, Na, Ca, Mg, Se, Sr, Mn, Zn and Fe in yak meat were determined by microwave digestion ICP-MS. The difference of mineral element content in yak meat from different regions and parts were analyzed. Results: There were extremely significant differences in mineral elements in different parts of the meat of similar Uqi yaks (P

The digestibility of myofibrillar proteins (MP) extracted from yak meat cooked to different internal temperatures of (40, 50, 60, 70 and 80 ℃) was determined during in vitro gastrointestinal digestion, and total carbonyl content, total sulfhydryl content and Schiff base content before and after digestion were measured. Ultraviolet (UV) absorption spectroscopy, endogenous fluorescence spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to investigate the oxidation and digestion patterns of yak meat proteins during gastrointestinal digestion. The results showed that total protease hydrolysis of MP from yak meat cooked to 60 ℃ was the highest after simulated gastric and intestinal digestion (88.64%). The rates of pepsin hydrolysis and total protease hydrolysis of MP from yak meat cooked to 80 ℃ decreased by 34.10% and 22.47%, respectively, and the rate of trypsin hydrolysis increased by 75.34% compared with MP from raw yak meat. The total carbonyl content after simulated gastric and intestinal digestion increased by 81.42% and 77.40%, respectively, and the total sulfhydryl content decreased by 30.02% and 36.43%, respectively, compared with raw MP. With an increase in cooking temperature, the Schiff base content gradually increased, the UV absorbance was significantly enhanced, and the endogenous fluorescence intensity was significantly reduced. The SDS-PAGE patterns showed that the protein bands were severely degraded and even disappeared after digestion. It was found that the digestibility of MP from yak meat cooked to 60 ℃ was the highest. The degree of protein oxidation in yak meat cooked to 80 ℃ was the strongest and increased during gastrointestinal digestion.

In order to explore the difference in flavor among yak leg meat roasted at different temperatures, sensory evaluation, gas chromatography-ion mobility spectrometry (GC-IMS), relative odor activity value (ROAV), partial least squares-discriminant analysis (PLS-DA), and principal component analysis (PCA) were used in this study. The results showed that the samples roasted at 240 ℃ for 7 min had the highest (E) sensory evaluation score. A total of 82 compounds were identified by GC-IMS, including 15 aldehydes, 12 alcohols, 24 lipids, 14 ketones, 7 heterocycles, 3 olefins, and 7 other compounds. The total amount of these compounds in sample E (240 ℃) was the highest, followed by samples D (180 ℃) and C (120 ℃). The total amount of these compounds in sample F (300 ℃) was lower than that in sample E (240 ℃). The key flavor compounds of roasted yak meat were ethyl 2-hydroxypropanoate, 4-methylguaiacol, 2-acetyl-1-pyrroline, 5-nonanone, ethyl salicylate, 1-propanol, (E,E)-2,4-heptadienal, 1-penten-3-one, (E)-2-heptenal, linalyl acetate, butanol-D, methional-M, 2-ethyl-6-methylpyrazine, 4-hexen-1-ol, (Z)-4-decenal, 2,4-heptadienal, 2-phenylethanol, and ethyl butyrate. Sample E had roasted meat-like, fatty, flowery and fruity aromas, which was the best among these five samples. The flavor of samples C and D was lower than that of sample E, having nutty, toasty, sweet and smoked aromas.

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Yak meat is a nutritious and environmentally friendly alternative to traditional meats, with high protein and low fat content. Yaks emit less methane and have higher nitrogen utilization efficiency than cattle, making them more sustainable. Yak meat is culturally significant and has market potential as a protein alternative that addresses animal welfare concerns. However, challenges exist in scaling up production, including economic constraints, consumer perceptions, and climate change. Efforts are needed to improve market access, consumer awareness, and the sustainability of yak production. Overall, yak meat has the potential to be a valuable and sustainable food source. [Extracted from the article]

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Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sarcoplasmic proteins (SP) derived from yak meat were oxidized by malondialdehyde (MDA) at different concentrations. The effects of lipid oxidation on physicochemical properties and color stability of SP were investigated by evaluating side-chain amino acid oxidation, protein structure and color of SP and the oxidation status of myoglobin (Mb). The results showed that after MDA oxidation, the a* value, b* value, C* value, and deoxymyoglobin and oxymyoglobin contents of SP significantly decreased (P < 0.05), and the L* value, metmyoglobin content, and ferrylmyoglobin concentration significantly increased (P < 0.05), indicating that MDA oxidation lowered color stability. The contents of carbonyl groups and dimeric tyrosine, the fluorescence intensity of SP-MDA adducts, and the relative contents of β-helix and β-turn significantly increased (P < 0.05), and total sulfhydryl content, surface hydrophobicity, intrinsic fluorescence intensity, and the relative contents of α-helix and random coil significantly declined (P < 0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed blurred expansion of small molecule bands and the formation of macromolecular aggregates, suggesting that MDA promoted the oxidation and aggregation of SP. Pearson correlation analysis revealed significant correlations between MDA oxidation and physicochemical properties and color stability of SP (P < 0.05). This study reveals that MDA alters the structure of SP by directly oxidizing it or mediating Mb oxidation, causing cross-linked aggregation of SP and reducing its color stability.

In order to study the effects of L-Lys on the quality characteristics and protein oxidation of yak meat induced by MDA. In this study, MDA was used as the simulated oxidation system, and yak meat were used as the research objects. The changes of edible quality, lipid oxidation, protein oxidation and muscle histological characteristics during storage were measured after yak meat treated with different concentrations of L-Lys and MDA. The results showed that 10 mmol/L L-Lys could reduce the increase of pH caused by MDA, alleviate the excessive increase of hardness and chewiness, and significantly inhibit the conversion of oxygenated myoglobin into high iron myoglobin, thereby increasing the L* value and a* value (P

The current study aimed to investigate the difference of volatile compounds in Qinghai Yushu yak. In this experiment, brisket, round, tenderloin, bottom round of yak was taken as the research object, the electronic nose, electronic tongue intelligent detection combined with the solid-phase microextraction-gas chromatography-mass spectrometry method (SPME-GC-MS) to analyze the flavor, the principal component analysis (PCA), the cluster analysis (CA) and correlation analysis (Pearson) of yak meat. The results showed that the taste intensity of electronic tongue was significantly different, the taste of different parts of yak meat was significantly different, and the taste of sample HT was better than that of other samples. The principal component analysis results of electronic nose showed that HT, HB and QT were close to the X axis, and the odor characteristics were similar. A total of 57 volatile compounds were detected in yak meat, including aldehydes (12 kinds), alcohols (11 kinds), hydrocarbons (11 kinds), acids (5 kinds), ketones (3 kinds), and other miscellaneous sulfur compounds (15 kinds). Among them, the results of PCA-GC-MS showed the contents of benzaldehyde, nonaldehyde, 2-ethyl-1-hexanol, m-xylene, allyl methyl sulfide and 2-acetylpyrrole in the bottom round of yak were significantly different from those in other parts, indicating that the flavor of bottom round of yak was significantly different from that in other parts which was the same as the results of electronic nose PCA showed that data analysis. The results would provide a theoretical basis and a data reference for the processing technology and flavor characteristic identification of yak in the future.

In order to clarify the synergistic effect of different concentrations of arginine and different concentrations of chitosan on the quality of yak meat during postmortem aging and its potential mechanism, in this study, different concentrations of arginine and different concentrations of chitosan were injected into yak meat to determine their effects on the quality of yak meat during postmortem aging. The results showed that the combination of 0.4%~0.8% arginine and 1.0% chitosan could significantly increase the pH value, reduce the L*, b* values, metmyoglobin and cooking loss of yak meat during postmortem aging, and increase a* value and oxymyoglobin (P0.05). Histological observation showed that the compound treatment was more conducive to the integrity and fullness of muscle cells, and reduced the water channel. In summary, the combination of different concentrations of arginine and different concentrations of chitosan improved the quality of postmortem yak meat during aging to a certain extent, improved its meat color stability and reduced cooking loss, promoted tenderization, and made muscle cells more complete and fuller, but it promoted fat oxidation and protein oxidation as a whole. The specific reasons and related mechanisms need to be further explored.

The effects of adding different levels (0.01%, 0.05% and 0.10%) of banana flower extract (BFE) versus dibutylated hydroxy toluene (BHT) on protein oxidation in naturally fermented yak meat sausages were investigated. lys The carbonyl content, Schiff base content, total sulfhydryl content, active sulfhydryl content, surface hydrophobicity, dimeric tyrosine content, endogenous fluorescence intensity and solubility of myofibrillar proteins (MPs) from fermented yak meat sausage were measured at different fermentation times, and the secondary structure and composition of MPs were characterized by Fourier transform infrared (FTIR) spectroscopy, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that compared with the blank control, the addition of BFE decreased the carbonyl group content, Schiff base content, surface hydrophobicity, dimeric tyrosine content and endogenous tryptophan fluorescence intensity of MPs, and increased the total sulfhydryl group content, active sulfhydryl group content and solubility. FTIR spectroscopy showed that the addition of BFE improved the reveal the more stability of the secondary structure of MPs. SDS-PAGE showed that BFE reduced the diffusion of myosin heavy chain and had a protective effect on myosin. This study showed that BFE inhibited protein oxidation in naturally fermented yak sausage, and this effect was positively correlated with BFE concentration, being most pronounced at 0.10% BFE concentration.

The present study aimed to shed light on the effects of altitudes and three cooking methods (boiling, steaming, and roasting) on the physicochemical quality, volatile profile, and sensorial characteristics of yak meat. Composite meat samples were prepared to represent each cooking method and altitude level from the longissimus thoracis et lumborum (LTL) muscle of nine yaks. The techniques employed were gas chromatography-mass spectrometry (GC–MS) and electronic nose (E-nose) along with chemometrics analysis to study the changes occurring in yak volatile profile, and TBARS measurement in lipid oxidation during cooking. Among the cooking methods, boiling and steaming exhibited higher protein and fat content while lower volatile compound contents. Additionally, roasted yak meat received the highest sensory scores, along with decreased L*-values, while elevated a*- and b*-values, and tenderness. A total of 138 volatile compounds were detected, and among them, 36 odorants were identified as odor-active compounds in cooked yak meat. It is evidenced that low-altitude yak presented more complex and richer flavor profiles than high-altitude ones. Moreover, yak meat from low- and high-altitude was classified into two groups by an electronic nose (E-nose) owing to distinct flavor characteristics. Overall, roasted yak meat originating from low altitudes tends to be more popular from a sensory perspective.

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Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To explore the effect of different levels of lipid oxidation on the structural and functional properties of myofibrillar protein (MP) in yak meat, the oxidation of side-chain amino acids, structure, rheological characteristics, and emulsion stability of MP incubated in the presence of different concentrations (0, 0.1, 1, 5, 10 and 20 mmol/L) of malondialdehyde (MDA) were measured. The results showed that with an increase in MDA concentration, the contents of carbonyl group, MDA-MP adducts and dimeric tyrosine and the relative content of β-turn in MP overall increased, while total sulfhydryl content, surface hydrophobicity, endogenous fluorescence intensity, and the relative contents of α-helix and β-sheet decreased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results indicated gradual loss of myosin heavy and light chains, implying that interaction with MDA could induce MP oxidation and cross-linked aggregation and result in structural transition from an ordered to a disordered state. In addition, moderate oxidation (with MAD concentration < 10 mmol/L) increased the storage and loss moduli and improved the gel quality of MP; however, excessive oxidation (with MAD concentration ≥ 10 mmol/L) led to serious aggregation of MP and a decrease in the storage and loss moduli as well as a decrease in the emulsion stability and color deterioration. In conclusion, MDA oxidation can promote the oxidation of MP, and alter the structural and functional properties.

To investigate the effects of freezing-thawing times on the collagen properties and the yak meat quality. The changes of shear force, pH, thawing loss, cooking loss, color difference, texture, collagen content and solubility, enzyme activity and microstructure of yak meat were analyzed on different freezing-thawing times. The results showed that with the increase of freezing-thawing times, the shear force of yak meat decreased by 59.72%, moreover，the collagen solubility, β-galactosidase and β-galacturonase activity, thawing loss, cooking loss and b* value of yak meat increased significantly (P

To investigate the effect of high-pressure processing (HPP) on the quality of yak meat, yak meat was processed under pressure at 200, 400, and 600 MPa for 480 seconds, respectively, and the sensory, pH, microorganism, color, protein, and lipid oxidation of yak meat stored at 4 °C for 0, 4, 8, 12, and 16 days was determined. The results showed that HPP significantly lowered the total number of colonies and total volatile basic nitrogen (TVB-N) during storage (P

Yak meat is nutritionally superior to beef cattle but has a low fat content and is slow-growing. The liver plays a crucial role in lipid metabolism, and in order to determine whether different feeding modes affect lipid metabolism in yaks and how it is regulated, we employed RNA sequencing (RNA-seq) technology to analyze the genome-wide differential gene expression in the liver of yaks maintained under different raising systems. A total of 1663 differentially expressed genes (DEGs) were identified (|log2FC| ≥ 0 and p-value ≤ 0.05), including 698 down-regulated and 965 up-regulated genes. According to gene ontology (GO) and KEGG enrichment analyses, these DEGs were significantly enriched in 13 GO terms and 26 pathways (p < 0.05). Some DEGs were enriched in fatty acid degradation, PPAR, PI3K-Akt, and ECM receptor pathways, which are associated with lipid metabolism. A total of 16 genes are well known to be related to lipid metabolism (e.g., APOA1, FABP1, EHHADH, FADS2, SLC27A5, ACADM, CPT1B, ACOX2, HMGCS2, PLIN5, ACAA1, IGF1, FGFR4, ALDH9A1, ECHS1, LAMA2). A total of 11 of the above genes were significantly enriched in the PPAR signaling pathway. The reliability of the transcriptomic data was verified using qRT-PCR. Our findings provide new insights into the mechanisms regulating yak meat quality. It shows that fattening improves the expression of genes that regulate lipid deposition in yaks and enhances meat quality. This finding will contribute to a better understanding of the various factors that determine yak meat quality and help develop strategies to improve yield and quality.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Tenderness is the main quality of meat products. However, the meat tenderness formation is a complex biological process, and pathways and proteins that affect the tenderness of yak meat are unknown. Methods Label‐free proteomics method was used to explore the effects of differentially expressed proteins on the tenderness of yak skeletal muscle (tenderloin) during post‐mortem storage (0, 3, and 7 days) at 3 ± 1°C. Results The tenderness of yak skeletal muscle improved significantly during storage. A total of 91 differentially expressed proteins of yak skeletal muscle during post‐mortem storage were identified by the following comparisons: day 3 versus 0, day 7 versus 0, and day 7 versus 3. NDUFS6, CYCS, COX6A2, LDB3, HSPB7, TPM4, TAGLN, COL1A1, LUM, MYH11, ACTC1, and MYOZ1 proteins showed a significant difference during yak skeletal muscle post‐mortem storage. Furthermore, bioinformatics analyses revealed that the identified proteins were related to carbon metabolism, citrate cycle, glycolysis, oxidative phosphorylation, and RNA degradation. Conclusion The results of the present study could provide proteomic insights into changes in yak skeletal muscle tenderness during storage and may be a valuable resource for future investigations.

This study examined the potential of hyperspectral techniques for the rapid detection of characteristic indicators of yak meat freshness during the oxidation of yak meat. TVB-N values were determined by significance analysis as the characteristic index of yak meat freshness. Reflectance spectral information of yak meat samples (400–1000 nm) was collected by hyperspectral technology. The raw spectral information was processed by 5 methods and then principal component regression (PCR), support vector machine regression (SVR) and partial least squares regression (PLSR) were used to build regression models. The results indicated that the full-wavelength based on PCR, SVR, and PLSR models were shown greater performance in the prediction of TVB-N content. In order to improve the computational efficiency of the model, 9 and 11 characteristic wavelengths were selected from 128 wavelengths by successive projection algorithm (SPA) and competitive adaptive reweighted sampling (CARS), respectively. The CARS-PLSR model exhibited excellent predictive power and model stability.

This study investigated the differences in meat quality during postmortem aging of yak meat from different altitudes as well as the relationship between the release of hypoxic factor HIF‐1α and meat quality. The results showed that the HIF‐1α increased with altitude but during aging process, there was an initial increase before a subsequent decrease (p <.05). Moreover, significant increases were showed in glycolytic potential, a* value, pH, HIF‐1α mRNA expression, HIF‐1α protein expression and shear force with altitude (p <.05). Additionally, the b* value, L* value, water holding power and MFI decreased significantly (p <.05). HIF‐1α was shown, by PLS‐DA method analysis, to be the main protein marker for differences in the quality during aging time of meat from three altitude groups. HIF‐1α protein expression was high correlated with glycolytic potential, pH value, meat color, tenderness and water holding capacity during postmortem aging. The results demonstrated that HIF‐1α is a novel marker protein that influences meat quality in yak from different altitudes and that HIF‐1α‐mediated glycolytic pathway was key to the meat quality during postmortem aging. Practical applications: Yak meat has the advantages of high protein, low fat, good amino acid and fatty acid composition, so the nutritional value of yak meat is in line with the current best‐selling beef with less fat in domestic and foreign markets. But consumers often think that the meat tenderness of yak meat is worse than that of beef and improving the quality of yak meat was worthy of attention specifically. This study investigated the differences in meat quality during postmortem aging of yak meat at different altitudes and the relationship between hypoxic factor HIF‐1α release and meat quality. [ABSTRACT FROM AUTHOR]

Yak meat is known for its unique flavor and high nutritional value. Its low output results in high prices, and as a result, food fraud is often committed in the marketplace by using low-value cattle meat with similar morphological characteristics to pass off as high-value yak meat. However, the current detection methods for yak meat authenticity are mostly confined to laboratories and suffer from expensive equipment, high professional requirements, and insufficient specificity, making it difficult to realize rapid on-site assay of yak meat authenticity. In this study, a duplex recombinase polymerase amplification combined with CRISPR/Cas12a-Cas12a assay strategy for rapid visual on-site identification of cattle- and yak-derived components was established. With only a portable box containing some cheap and small equipment, the method can accurately identify the authenticity of yak meat products within 1 h. It has been verified that to this method's detection limit can reach to 1 % (w/w) at least for the cattle meat, regardless of raw or cooked products. After testing the blind samples, 52.8 % of the yak meat products were adulterated, which was consistent with the results of the real-time PCR method, proving that the method has good accuracy and practicability. It can be used to achieve accuracy, rapid and on-site assay of the authenticity of various yak meat products. • A novel dRPA-Cas-Cas method has been developed for on-site authentication of yak meat. • The fake yak meat products can be identified within 1 h using a portable equipment box. • The LOD for adulterated cattle meat in raw or cooked yak meat products can be at least 1 % (w/w). • The accuracy of this method was validated to be consistent with the real-time PCR. [ABSTRACT FROM AUTHOR]

Realizing the market value of grassland resources is of great significance to finding a balance between ecological protection and economic development. As a unique livestock animal that is native to the Qinghai-Xizang Plateau, the yak plays an important role in maintaining ecosystem stability, ensuring the livelihoods of herdsmen, promoting socio-economic development, and preserving ethnic cultural traditions. However, given its small market share, little is known about the factors that drive Chinese consumer preferences for yak meat. This study aimed to investigate consumer preferences for yak meat by means of an online survey involving a sample of 2999 respondents from five cities in China. The best-worst scaling method was employed to measure the relative importance of different attributes of yak meat by using a purchasing scenario. The results indicated that quality-safety certification, freshness, and production sustainability were regarded as the most preferred attributes, whereas animal welfare, brand, and the purchasing channel were found to be the least preferred. In addition, significant heterogeneity was detected in consumer preferences. Consumers were divided into three classes, namely 'Price Sensitive Consumers,' 'Environmentally Friendly Consumers,' and 'Yak Meat Inclined Consumers,' respectively. Our findings might be helpful for policymakers and yak meat producers to develop targeted strategies to facilitate the sale of yak meat and then restore degraded grasslands. [ABSTRACT FROM AUTHOR]

The work aimed to study the effect of four drying methods, namely constant temperature hot air drying (HD), microwave drying (MD), hot air microwave drying (HMD), and gradient hot air drying (GHD), on quality characteristics of dried yak meat. The analyses of physicochemical, textural, flavor, and sensory characteristics were carried out based on these four drying methods. The results revealed that microwave dried yak jerky exhibited better color and received the highest sensory score. Hardness of samples were affected by the drying methods, which showed significant differences. There were 21 free amino acids (FAAs) detected in dried yak samples. The samples treated by microwave drying showed the highest total free amino acid content (73.30 mg/100 g) and the EUC value was significantly higher than other methods, indicating the sample displayed greater flavor. A total of 153 volatile compounds were identified in dried yak meat samples, primarily including aldehydes, ketones, and esters. Moreover, the sensory evaluation indicated that the drying methods could significantly affect on color, flavor, and overall acceptability of different samples. Microwave drying samples scored higher than other drying methods. Overall, considering aspects of quality, time savings, and energy efficiency, microwave drying of yak jerky emerges as a more satisfactory option. This study could provide important theoretical support for the application of drying methods to improve the quality of yak jerky and enhance production efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxidative stress(OS) and protein S-nitrosylation(SNO) interaction regulates tenderness. • Interaction of OS with SNO impairs GSH and TRX response systems causing apoptosis. • Interaction between OS and SNO accelerates the Ca2+ release process causing apoptosis. • Interaction between OS and SNO positively regulates yak meat tenderization. To reveal the interaction of oxidative stress and protein S-nitrosylation on mitochondrial pathway apoptosis and tenderness development in postmortem yak meat. Herein, we selected yak longissimus dorsi muscle as the research object and treated hydrogen peroxide (H 2 O 2) with S-nitrosoglutathione agent (GSNO) as well as Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) in mixed injections with 0.9 % saline as a control group, followed by incubation at 4 °C for 12, 24, 72, 120 and 168 h. Results showed that this interaction significantly increased mitochondrial ROS and NO content (P < 0.05) while weakening the antioxidant capacity of GSH and TRX redox response systems or accelerating the Ca2+ release process, leading to mitochondrial functional impairment and increased apoptosis rate. Notably, the H 2 O 2 + L-NAME group showed more pronounced apoptosis. Hence, we suggest that the interaction between oxidative stress and protein S-nitrosylation could positively regulate yak meat tenderization. [ABSTRACT FROM AUTHOR]

Irradiation's effects on quality, volatile compounds, and differential metabolites of yak meat were studied. Irradiation dose at 3 kGy had no effect on yak meat quality, however irradiation dose at 5 kGy resulted in yak meat quality deterioration as well as considerable irradiated off-flavors. And the level of the off-odor was strongly associated with the irradiation dose, and allyl methyl sulfide, octanal, nonanal, benzaldehyde, and 4-methylthiazole were all significant producers of off-odor. Meanwhile, with the increased of radiation dose, the amounts of cysteine, methionine, proline, linoleic acid, stearic acid changed obviously. The main generation pathway of irradiated off-flavors in yak meat were thought to be cysteine and methionine metabolism, and linoleic acid metabolism. The oxidative decomposition of sulfur-containing amino acids and unsaturated fatty acids may cause the off-flavor of irradiation yak meat. This research established a theoretical foundation for future control systems to prevent flavor quality alterations during irradiation preservation.

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The impacts of natural antioxidants, including ferulic acid, diallyl sulfide, α-tocopherol, and rutin, at a level of 0.2 g/kg on lipid and protein oxidation of minced yak meat in a hydroxyl-radical-generating system were investigated, and the effectiveness was compared with synthetic antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT). The exposure of yak meat to oxidative stress from 12 h to 24 h elevated lipid and protein oxidation. Treatments with antioxidants resulted in significantly lower peroxides, conjugated dienes, and thiobarbituric acid-reactive substances, and were also effective in retarding the formation of carbonyl groups, reducing the loss of sulfhydryl groups and protecting α-helix contents, of which ferulic acid and rutin were the most effective. Myosin heavy chain underwent lower degradation in the samples treated with ferulic acid or rutin compared with the oxidized control and other antioxidant treatments, while that of the BHT treatment showed a similar intensity with oxidized control at 24 h of oxidation. The physical stability of myofibrillar proteins in samples with antioxidants from high to low was rutin, ferulic acid, α-tocopherol, and BHT~diallyl sulfide. These results indicate that rutin and ferulic acid may be promising antioxidants in inhibiting the oxidative reactions during the processing of yak meat. [ABSTRACT FROM AUTHOR]

The effects of low doses of sodium nitrite on yak meat colouring, myoglobin oxygenation status, myoglobin aggregation and myoglobin structure were evaluated using Fourier transform infrared spectroscopy, laser micro-Raman spectroscopy and liquid chromatography-electrospray ionization tandem mass spectrometry. The results showed that the yak meat redness value increased steadily relative to that of the control after the addition of low dose sodium nitrite. The nitrosomyoglobin level gradually increased and was significantly higher in the sodium nitrite-treated group than in the control group. The secondary structures were also transformed. The Cα-N bond extended and then contracted, the area of the haem core decreased and then increased and the frequency of contraction increased. A total of 34 nitrosylated peptides were identified, of which 15 were stable and 19 were unstable. These findings show that low doses of sodium nitrite facilitated the dynamic transformation of the myoglobin nitrosylated peptide fragment, which in turn preserved the colour of the meat.

Background: Tenderness is the main quality of meat products. However, the meat tenderness formation is a complex biological process, and pathways and proteins that affect the tenderness of yak meat are unknown. Methods: Label‐free proteomics method was used to explore the effects of differentially expressed proteins on the tenderness of yak skeletal muscle (tenderloin) during post‐mortem storage (0, 3, and 7 days) at 3 ± 1°C. Results: The tenderness of yak skeletal muscle improved significantly during storage. A total of 91 differentially expressed proteins of yak skeletal muscle during post‐mortem storage were identified by the following comparisons: day 3 versus 0, day 7 versus 0, and day 7 versus 3. NDUFS6, CYCS, COX6A2, LDB3, HSPB7, TPM4, TAGLN, COL1A1, LUM, MYH11, ACTC1, and MYOZ1 proteins showed a significant difference during yak skeletal muscle post‐mortem storage. Furthermore, bioinformatics analyses revealed that the identified proteins were related to carbon metabolism, citrate cycle, glycolysis, oxidative phosphorylation, and RNA degradation. Conclusion: The results of the present study could provide proteomic insights into changes in yak skeletal muscle tenderness during storage and may be a valuable resource for future investigations. [ABSTRACT FROM AUTHOR]