Tan Mutton Research Articles

Electrostatically-enhanced two-stage low-temperature tempering: Effects on the quality of frozen tan mutton

The two-stage low-temperature tempering (TLT) and TLT assisted by electrostatic fields (TLT-1500/2000/2500/3000) were developed to investigate their effects on the quality of frozen Tan mutton. The results demonstrated that both TLT and TLT-1500/2000/2500/3000 significantly (P < 0.05) enhanced the tempering rate compared to refrigerator tempering (4 °C, RT). The analysis of tempering, cooking, and centrifugal losses, along with the evaluation of electrical conductivity, pH, and TVB-N, showed that the water retention capacity and freshness of Tan mutton treated with TLT-2500 were closest to those of fresh Tan mutton. Scanning electron microscopy analysis demonstrated that TLT-2500 best maintained the tissue integrity of Tan mutton, while low-field nuclear magnetic resonance analysis revealed it contained the highest immobile water and least free water. Furthermore, Tan mutton treated with TLT-2000 and TLT-2500 exhibited minimal lipid oxidation and color change. In contrast, the most significant changes in all indicators were observed after RT.

Development and characterization of a new potato starch/watermelon peel pectin composite film loaded with TiO2 nanoparticles and microencapsulated Lycium barbarum leaf flavonoids and its use in the Tan mutton packaging

Reinforced edible film with active nanoparticles has been in increasing demand as a new technology to improve the quality and extend the shelf-life of muscle foods. The study aimed to fabricate and characterize a novel potato starch (Pst)/watermelon peel pectin (Wpp) composite film with the microencapsulated Lycium barbarum leaf flavonoids (MLF) and nano-TiO2 (Pst/Wpp/MLF/TiO2) and further apply the film in Tan mutton preservation. The moisture content, thickness and water vapor permeability (WVP) of the composite film were relatively increased with increasing the percentage of MLF, while nano-TiO2 had slight influence on the thickness, but leaded to a significantly decreased the moisture content and WVP. Also, the SEM images showed that the roughness and porosity were created on the film surface by adding MLF and nano-TiO2. FTIR revealed electrostatic and hydrogen bond interactions between the components in the film system. Meanwhile, MLF and nano-TiO2 effectively enhanced the mechanical strength, UV-barrier, controlled-release, thermal stability, antimicrobial and antioxidation properties of the Pst/Wpp film. Also, the composite film containing MLF and nano-TiO2 significantly inhibited the growth of microorganisms and chemical deterioration of mutton samples, which suggested that such film has potential as a prospective active packaging for preserving Tan mutton.

Characterization and Discrimination of Volatile Compounds in Chilled Tan Mutton Meat during Storage Using HiSorb-TD-GC-MS and E-Nose

Chilled Tan mutton is currently the mainstream of Tan mutton production and consumption in China, but the reports on chilled meat quality evaluation and shelf-life discrimination by volatiles are limited. This study aimed to investigate the changes of volatile compounds in chilled Tan mutton at four storage stages (1d, 3d, 5d, 7d) in order to differentiate the various storage stages. An analysis protocol was established for the characterization and discrimination of the volatiles in chilled Tan mutton based on high capacity sorptive extraction-thermal desorption-gas coupled with chromatography-mass spectrometry (HiSorb-TD-GC-MS), electronic nose (E-nose), and multivariate statistical analysis. A total of 96 volatile compounds were identified by HiSorb-TD-GC-MS, in which six compounds with relative odor activity value &gt;1 were screened as the key characteristic volatiles in chilled Tan mutton. Four storage stages were discriminated by partial least squares discriminant analysis, and nine differential volatile compounds showed a variable importance for the projection score &gt;1, including octanoic acid, methyl ester, decanoic acid, methyl ester, acetic acid, heptanoic acid, methyl ester, propanoic acid, 2-hydroxy-, methyl ester, (ñ)-, hexanoic acid, propanoic acid, butanoic acid, and nonanoic acid. With the volcano plot analysis, hexadecanoic acid, methyl ester, was the common volatile marker candidate to discriminate chilled stages of Tan mutton. Meanwhile, E-nose could discriminate chilled Tan mutton at different storage stages rapidly and efficiently using linear discriminant analysis. Furthermore, E-nose sensors could obtain comprehensive volatile profile information, especially in esters, acids, and alcohols, which could confirm the potential of E-nose for meat odor recognition. Thus, this analysis protocol could characterize and discriminate the volatiles in chilled Tan mutton during storage.

Combination of hyperspectral imaging and entropy weight method for the comprehensive assessment of antioxidant enzyme activity in Tan mutton

The antioxidant enzymes play the crucial role in inhibiting mutton spoilage. In this study, visible near-infrared (Vis-NIR) hyperspectral imaging (HSI) combined with entropy weight method (EWM) was developed for the first time to evaluate the antioxidant properties of Tan mutton. The comprehensive index of antioxidant enzymes (AECI) consisting of peroxidase (49.34%), catalase (37.97%) and superoxidase (12.69%) was constructed by the EWM. Partial least squares regression, least squares support vector machine and artificial neural networks (ANN) were developed based on characteristic wavelengths extracted by successful projections algorithm, uninformative variable selection, iteratively retains informative variables (IRIV), regression coefficient and competitive adaptive reweighted sampling (CARS). The textural features (TF) were extracted by the gray level co-occurrence matrix and fused with the spectral data to establish models. Visualization of the changes in antioxidant enzyme activity was constructed from the optimal model. In addition, two-dimensional correlation spectra (2D-COS) with AECI as a perturbation variable was used to identify spectral features, revealing chemical bond changes order under the characteristic peaks at 612–799–473–708–559 nm. The results showed that the IRIV-CARS-TF-ANN model performed the best, with prediction set coefficient of determination (RP2) of 0.8813, which improved 2.12%, 1.11% and 2.77% over the RP2 of full band, IRIV and IRIV-CARS, respectively. It was suggested that fusion data of HSI may effectively predict the activity of antioxidant enzymes in Tan mutton.

Evaluation of key aroma compounds and protein secondary structure in the roasted Tan mutton during the traditional charcoal process.

The traditional charcoal technique was used to determine the changes in the key aroma compounds of Tan mutton during the roasting process. The results showed that the samples at the different roasting time were distinguished using GC-MS in combination with PLS-DA. A total of 26 volatile compounds were identified, among which 14 compounds, including (E)-2-octenal, 1-heptanol, hexanal, 1-hexanol, heptanal, 1-octen-3-ol, 1-pentanol, (E)-2-nonenal, octanal, 2-undecenal, nonanal, pentanal, 2-pentylfuran and 2-methypyrazine, were confirmed as key aroma compounds through the odor activity values (OAV) and aroma recombination experiments. The OAV and contribution rate of the 14 key aroma compounds were maintained at high levels, and nonanal had the highest OAV (322.34) and contribution rate (27.74%) in the samples after roasting for 10 min. The content of α-helix significantly decreased (P < 0.05), while the β-sheet content significantly increased (P < 0.05) during the roasting process. The content of random coils significantly increased in the samples roasted for 0-8 min (P < 0.05), and then no obvious change was observed. At the same time, β-turn content had no obvious change. Correlation analysis showed that the 14 key aroma compounds were all positively correlated with the content of α-helix and negatively correlated with the contents of β-sheet and random coil, and also positively correlated with the content of β-turn, except hexanal and 2-methypyrazine. The results are helpful to promoting the industrialization of roasted Tan mutton.

Study on key aroma compounds in the electric roasting process of Tan mutton

Study on key aroma compounds in the electric roasting process of Tan mutton

Relationship between rumen microbial differences and traits among Hu sheep, Tan sheep, and Dorper sheep.

Rumen microbes play an important role in the growth and development of ruminants. Differences in variety will affect the rumen community structure. The three excellent sheep breeds were selected for this study (Hu sheep, Tan sheep, and Dorper sheep) have different uses and origins. The sheep were raised on the same diet to 180 d of age in a consistent environment. 16S rDNA V3 to V4 region sequencing was used to assess the rumen microbes of 180 individuals (60 per breed). There were differences in microbial diversity among different sheep breeds (P < 0.05). Principal coordinate analysis showed that the three varieties were separated, but also partially overlapped. Linear discriminant analysis effect size identified a total of 19 biomarkers in three breeds. Of these biomarkers, five in Hu sheep were significantly negatively correlated with average feed conversion rate (P < 0.05). Six biomarkers were identified in the rumen of Dorper sheep, among which Ruminococcus was significantly positively correlated with body weight at 80 d (P < 0.05). In Tan sheep, Rikenellaceae_RC9_gut_group was significantly positively correlated with meat fat, and significantly positively correlated with volatile fatty acids (VFAs), such as butyric acid and isobutyric acid (P < 0.05). The Rikenellaceae_RC9_gut_group may regulate Tan mutton fat deposition by affecting the concentration of VFAs. Functional prediction revealed enrichment differences of functional pathways among different sheep breeds were small. All were enriched in functions, such as fermentation and chemoheterotrophy. The results show that there are differences in the rumen microorganisms of the different sheep breeds, and that the microorganisms influence the host.

Rapid evaluation of texture parameters of Tan mutton using hyperspectral imaging with optimization algorithms

The detection of meat texture is of great value because it is the key factor that drives consumer purchasing decisions. In this study, a hyperspectral imaging (HSI) system was utilized to determine the texture parameters of Tan mutton. In order to observe the influence of mutton spectra during different refrigeration periods for modeling, hyperspectral images of the Tan mutton samples were collected in the 900–1700 nm spectral range, and the correction models of Tan mutton texture parameters were established. The four machine learning algorithms, such as partial least squares regression (PLSR), least squares support vector machine (LSSVM), random forest (RF), and decision trees (DT), were developed to establish the spectral models based on the characteristic bands selected by different extraction strategies including interval variable iterative space shrinkage approach (iVISSA), competitive adaptive reweighted sampling (CARS), successive projection algorithm (SPA) and variable combination population analysis (VCPA). The results showed that the LSSVM-iVISSA-CARS models exhibited excellent performance in predicting hardness and gumminess with root-mean-square errors (RMSEP) of 5.259 and 3.051 as well as the coefficient of determination for the prediction data set (R p 2 ) of 0.986 and 0.984 respectively. Good performances were achieved with R p 2 of 0.987 and RMSEP of 4.970 with the LSSVM-iVISSA-SPA model for chewiness, respectively. Therefore, HSI has potential for the evaluation and prediction of texture parameters in Tan mutton. • Spectra at 900–1700 nm was applied for detecting texture parameters of Tan mutton. • The OSC and MC methods were both utilized to preprocess X-block and Y-block. • Informative wavelengths were selected using iVISSV-CARS and iVISSV-SPA approaches. • The LSSVM model yielded the best result in predicting hardness, gumminess and chewiness of Tan mutton.

Quantitative Detection of Myoglobin Content in Tan Mutton During Cold Storage by Near-infrared Hyperspectral Imaging

Quantitative Detection of Myoglobin Content in Tan Mutton During Cold Storage by Near-infrared Hyperspectral Imaging

Changes in oxidation and secondary structure of myofibrilla protein, water distribution, and quality of vacuum packaged Tan mutton during storage at different temperatures

Changes in myofibrilla protein oxidation and structure, water dynamics, and quality of tan mutton stored at superchilling (−2°C), frozen (−18°C), and chilling (4°C) conditions were investigated. Results indicated that tan mutton stored in superchilling demonstrated better color stability in comparison with those in chilling. Superchilling exhibited better WHC and tenderness than those of frozen. And the level of protein oxidation was lowest and protein secondary structure was most stable under superchilling. During storage, the fluctuation of immobilized water and free water was significant (p < .05). The correlation analysis confirmed that the quality deterioration of muscle may be induced by the oxidation and structural destruction of protein during storage. According to water distribution, we speculated that the effect of the size and rate of ice crystal formation on meat quality during storage is worthy of attention. Overall, superchilling is the most favorable for maintaining physiological and biochemical parameters for meat. Practical applications Superchilling storage was found to preserve the quality of Tan mutton with the least side effects as compared to chilled and frozen storage, and we provide some recommendations for more beneficial to improve superchilling preservation technology of Tan mutton.

The change of rheological property in Tan mutton tissue during storage

Taking different parts of Tan mutton in Ningxia as samples, the rheological properties of Tan mutton at 0, 2, 4, and 8 days were studied by rotational rheometer. The stress relaxation under static state and the dynamic oscillation rheological properties in flow state was examined. The dynamic storage modulus, loss modulus, and complex viscosity with angular frequency were measured. The microstructure of Tan sheep was observed by field emission scanning electron microscope (FESEM) to elucidate the changes of surface microstructure of muscle fibers. The results showed that the Tan mutton was a non-Newtonian fluid and exhibits pseudoplastic behavior. The apparent viscosity decreased with the increase of shear rate. The longissimus dorsi muscle was stored in 2, 4, 6, and 8 days. The Ostwald-de Waele model had a coefficient of fit of 0.9245, 0.986, 0.992, 0.986, and the Ostwald-de Waele model of the hind legmuscles at 2, 4, 6, and 8 days had a coefficient of fit of 0.744, 0.911, 0.346, and 0.604. The model fitting effect of the long muscle was better than that of the hind leg muscle, which indicated that the flow effect of the longissimus dorsi muscle was better than that of the hind leg muscle during processing. Overall, the Ostwald de Waele model could better describe the flow properties of meat emulsions, which was better than the Herschel Bulkley model. Practical applications In this study, we have demonstrated that rheological property of Tan mutton was changed with the extension of time. This study can provide theoretical guidance for the improvement of meat deep processing technology.

Proteomics analysis to investigate the effect of oxidized protein on meat color and water holding capacity in Tan mutton under low temperature storage

This study aimed to investigate the effects of oxidized proteins on meat color and water holding capacity of Tan mutton stored at low temperatures and the correlation between oxidized proteins and meat quality. Compared with the fresh control group, a total of 1089 proteins were identified as shared proteins with different oxidation sites (DOSPs) in Tan mutton from three low temperature groups (−2, −18 and 4 °C). The number of oxidation sites in Tan mutton muscle stored at −2 °C was much higher than those at −18 and 4 °C. There were also differences in the degree and site of protein oxidation between different storage groups. Pearson's correlation analysis between 275 DOSPs and quality traits of the tan mutton muscle stored at low temperatures showed that 19 DOSPs were correlated closely with color (L*, a* and b*) and water holding (CeL, CL and DL). Among them, several proteins might be potential markers for color, and some proteins are good candidate predictors for water holding of Tan mutton muscle. Bioinformatics analysis showed that most of these proteins were structural proteins and metabolic enzymes, which may lead to the change of meat quality by affecting the microstructure and metabolic pathway of muscle.

Relationship between quality changes of post-rigor tan mutton and myofibrillar protein following high-pressure treatment

ABSTRACT Microbial load, protein oxidation, myofibrillar protein changes and quality characteristics (meat color and water retentiveness including centrifugal loss (CeL) and water-holding capacity (WHC)) of post-rigor tan mutton exposed to different high-pressure treatments (200 MPa/500 MPa for 15 min at 18°C) during chilled storage for 7 days (4°C) were evaluated. High-pressure applications of 200 MPa and 500 MPa significantly reduced the number of Total Viable Counts (TVC) during storage (P < 0.05), but excessive pressure treatment (500 MPa) also resulted in a significant increase in protein oxidation and decrease in water retentiveness (P < 0.05), accompanied by deterioration of meat color. 200 MPa treatment also caused adverse effects on the quality of processed meat at the later stage of storage (3–7 d) similar to 500 MPa high pressure, but the initial application of 200 MPa pressure resulted in no significant differences in meat color and retentiveness from the untreated (P > 0.05) and better texture characteristics than untreated samples. ANOVA with Partial Least Squares Regression (APLSR) confirmed the relationshipS between these variations in quality characteristics induced by high-pressure treatments and protein oxidation and key myofibrillar skeleton proteins.

Correlation among serum biochemical indices and slaughter traits, texture characteristics and water-holding capacity of Tan sheep

This study was conducted to determine the correlation among serum biochemical indices, slaughter traits, texture characteristics and water-holding capacity in Tan sheep. Eighty Tan sheep aged 4–6 months were selected. Blood samples were collected from live animals to analyse serum biochemical indices. The slaughter traits, texture characteristics and water-holding capacity of meat were assessed after slaughter. There were highly significant correlations (p<.01) and high linear regression R values among serum biochemical indices, slaughter traits, meat texture characteristics and water-holding capacity in Tan sheep. Therefore, this study has demonstrated that the meat qualities of Tan mutton may be evaluated by the serum biochemical indices of live Tan sheep. Highlights This study was conducted to determine the correlation among serum biochemical indices, slaughter traits, texture characteristics and water-holding capacity in Tan sheep. This study has demonstrated that meat qualities of Tan mutton may be assessed by the serum biochemical indices of live Tan sheep. It is necessary to determine slaughter traits, meat texture characteristics and water-holding capacity of meat, which are major indicators for assessing meat and meat products by consumers.

Quality changes in high pressure processed tan mutton during storage.

The current study investigated the effects of high pressure (HP) treatment at 200 MPa and 500 MPa on quality characteristics of post-rigor tan mutton stored for 7 days at 4 °C, and textural changes were monitored during storage by means of the stress relaxation test. Application of 500 MPa high pressure significantly increased the elasticity and stiffness of meat after 7 days of storage (P < 0.05), accompanied by a lighter and less red appearance and markedly enhanced centrifugal loss during storage campared to untreated (P < 0.05). High pressure treatment at 200 MPa also substantially increased the lightness of samples throughout storage (P < 0.05), and showed a significant increase in stiffness at the end of storage (P < 0.05). Immunoblotting and electrophoresis (SDS-PAGE) analysis of key structural proteins revealed that myosin heavy chain denaturation began at 200 MPa, while actin denaturation occurred at 500 MPa. Troponin-T was continuously degraded in different treatments as storage progressed, and 200 MPa treatment and untreated represented similar degradation patterns, while 500 MPa treatment displayed more intense intact troponin-T at 38 kDa degradation. Results suggest that HP induced changes in cytoskeleton proteins, thereby affecting texture, water holding properties and lightness.

Development of a novel quantitative function between spectral value and metmyoglobin content in Tan mutton

This study was aimed to establish a quantitative function between spectral reflectance values and metmyoglobin (MetMb) content in Tan mutton during refrigeration. Near-infrared hyperspectral data combined with generalized two-dimensional correlation spectroscopy (G2D-COS) method to identify characteristic bands and investigate the sequence of chemical waveband changes. Characteristic wavebands identified by G2D-COS analysis had the best performance in predicting the content of MetMb, with a high R2p of 0.849, a low RMSEP of 2.695 and a high RPD of 2.786. The results showed that the G2D-COS may be a powerful tool for describing intensity changes of MetMb band. The partial least square regression method was used to develop the relationships between the spectral values and MetMb content in Tan mutton meat for predicting MetMb content. This study has provided a convenient and rapid non-destructive quantitative method for assessing the color of Tan mutton meat.

Effects of ficin, high pressure and their combination on quality attributes of post-rigor tan mutton

The effects of high pressure (HP) and ficin treatments, and their combinations on the quality characteristics of post-rigor tan mutton were investigated. HP at 150 MPa/15 min significantly increased the hardness and centrifugal loss (CeL) of meat and deteriorated the meat color, and ficin at 0.10 g/L reduced meat hardness by 8% and protected meat color but increased CeL significantly (P < 0.05). Initial ficin (0.10 g/L) injection and incubation at 55 °C for 60 min, followed by HP at 50 MPa/15 min and 150 MPa/15 min reduced the hardness of the treated meat by 48% and 41% respectively, and cooking loss (CL) and CeL were also significantly decreased (P < 0.05), yet ficin combined with 150 MPa markedly increased the levels of thiobarbituric acid reactive substances (TBARS), lightness (L*) and yellowness (b*) of the processed meat. Water retentiveness and tenderness enhanced by combined treatments were found to be mainly attributed to increased degradation of myofibrillar and sarcoplasmic proteins through ANOVA-Partial least squares regression (APLSR), and sensory evaluation verified the high acceptability of the meat treated by both HP and ficin in terms of tenderness, flavour and texture after cooking.

The effects of high pressure on the myofibrillar structure and meat quality of marinating Tan mutton

AbstractLamb leg meat (LLM) was marinated using solution of sodium chloride (NaCl) concentrations (0.04 g/g) for 15 min under high pressure (HP) treatment (100–400 MPa, 25°C) to investigate meat characteristics, volatile components and microstructure. HP treatment increased process yields during marinating, especially at 200 MPa, the shearing force and hardness reached their minimum value, which indicated that HP treatment (200 MPa) can effectively improve the tenderness of LLM. The electron microscopy revealed that HP modified the myofibrillar structure in the leg muscles. With the rise of pressure, the lightness (L*) value increased significantly. The red/green hue (a*) reached the maximum value at 200 MPa. HP influenced the formation of some key volatile compounds in LLM. LLM pressurized at 200–400 MPa had lower levels of furfural than control group, LLM pressurized at 200 MPa had higher levels of N‐nonanal and N‐octanal, lower levels of palmitic acid, but oleic acid and stearic acid was not detected. Only at 200–400 MPa, 2,3‐octanedione and 2‐octanone were detected in HP‐treated LLM.Practical applicationsHigh‐pressure (HP) is an effective technology as a pretreatment to postslaughter meat. Advantages include opportunities to improve tenderness and other characteristics of processed meat products by appropriate use of this technique. This study showed that application of high‐pressure premarinated treatment (200 MPa, 15 min, 25°C and 0.04 g/g salt content) could effectively improve the muscle fiber structure of lamb leg, several major volatile substances and tenderness. This work verifies the potential of HP for improving LLM characteristics and volatile components. These results can be beneficial for the applications of pressurized mutton in the mutton industry.

Investigation on Texture Changes and Classification between Cold-Fresh and Freeze-Thawed Tan Mutton

To study the texture, microstructural changes, and classification of cold-fresh (C-F), freeze-thawed once (F-T0), and freeze-thawed twice Tan mutton (F-Tt), the aforementioned three types of Tan mutton were subjected to near-infrared hyperspectrum scanning, scanning electron microscopy, and TPA testing. The original spectrum of Tan mutton was obtained at a wavelength range of 900∼1,700 nm after hyperspectrum scanning; a spectrum fragment ranging from 918 nm to 1,008 nm was intercepted, and the remaining original spectrum was used as a studied spectrum (“full spectrum” hereafter). The full spectrum was pretreated by SNV (standard normal variate), MSC (multiple scattering correction), and SNV + MSC and then extracted feature wavelengths by SPA (successive projections algorithm) and CARS (competitive adaptive reweighted sampling) algorithm, and 25 feature wavelengths were obtained. By combining these feature wavelengths with classified variables, the SNV + MSC−CARS−PLS-DA (partial least squares-discriminate analysis, PLS-DA) and SNV + MSC−SPA−PLS-DA models for classification of C-F and F-T Tan mutton were established. In contrast, SNV + MSC−CARS−PLS-DA yielded the highest classification rate of 98% and 100% for calibration set and validation set, respectively. The results indicated that the texture and surface microstructure of F-T Tan mutton deteriorated, and more worsely with F-T time. SNV+MSC-CARS-PLS-DA could be well used to classify C-F, F-T0, and F-Tt Tan mutton.

不同贮藏温度下滩羊肉pH值的近红外高光谱动力学模型建立

不同贮藏温度下滩羊肉pH值的近红外高光谱动力学模型建立