Tibetan sheep from different altitudes exhibit unique meat quality attributes, whereas the molecular mechanisms remain unelucidated. Such meat quality attributes are associated with underlying metabolic processes, which are influenced by high-altitude conditions. Herein, meat quality and muscle metabolism in Tibetan sheep from Oula (2900 m), Huoerba (4000 m), and Duoma (5100 m) were compared. Oula sheep showed higher moisture and lighter color, while Duoma sheep had the lowest fat content. A total of 419 differential metabolites were identified based on metabolomics. Among them, peptide contents decreased with increasing altitude of Tibetan sheep's residence, while carnitine derivatives increased. Bioinformatics analysis indicated that high altitude regulates HIF-1α signaling through hypoxic conditions and oxidative stress mediates glutathione oxidation, thus affecting meat L* value. This study reveals meat quality and the metabolic basis in Tibetan sheep at different altitudes, establishing a scientific foundation for resource utilization and development of Tibetan sheep at specific altitudes.

Lipid composition affects the metabolic processes underlying pork quality, but the lipid profile and its evolution mechanisms remain elusive. Herein, a quantitative lipidomics methodology was established to identify key lipid molecules and their transformations in Longissimus lumborum during storage. A total of 2148 lipid molecules were identified, with the content of most glycerophospholipids and sphingolipids showing dynamic changes during storage (p < 0.05). Using the Short Time-series Expression Miner, we discerned six significantly enriched profiles among 765 lipid molecules (p < 0.05), revealing a marked increase in the levels of coenzyme Q, ceramide, and acyl carnitine during storage. In addition, 33 discriminative lipid molecules were identified through partial least squares discriminant analysis, highlighting the key role of phospholipid and triglyceride degradation induced by lipase and coenzyme in pork spoilage. Bioinformatics analysis revealed that lipids containing unsaturated fatty acid (FA) branches, including phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and triglyceride, promote FA oxidation by participating in linoleic acid metabolism. Collectively, this study deciphers temporal lipid dynamics and oxidative metabolic networks in refrigerated pork, providing mechanistic insights for optimizing meat quality evaluation.

Utilization of collagen is key to the deep processing of animal skin. To develop a new type of fat substitute based on collagen protein, the texture, water mobility, and microstructure of sheepskin collagen-chitosan double-network emulsion gels were analyzed. The results indicated that the addition of 5% chitosan significantly increased gel hardness, and a collagen concentration of 7% achieved a water-holding capacity of 91.27%. Fourier transform infrared spectroscopy analysis showed red shifts in the amide I band and weakened –OH stretching, indicating electrostatic interactions between collagen and chitosan contributed to gel stabilization. Confocal laser scanning microscopy and scanning electron microscopy results revealed a uniform honeycomb-like microstructure of double-network emulsion gels, which could be affected by the amount of sheepskin collagen and chitosan. In conclusion, the sheepskin collagen-chitosan double-network emulsion gels exhibited both high mechanical strength and excellent water retention, it could be a potential choice for new type of fat substitute.

To evaluate a novel double-network emulsion gel composed of sheepskin collagen and chitosan (C-CG) as fat replacer in low-fat lamb patties, the effects of varying replacement levels of fat (0%, 20%, 40%, 60%, 80%, and 100%) on physicochemical and sensory properties of lamb patties were investigated. The results revealed that while C-CG substitution enhanced water-holding capacity (WHC) and moisture retention, its effect on textural attributes was non-linear. The 40% C-CG substitution level provided the optimal balance, delivering a high WHC (96.23%), a substantially reduced cooking loss (13.56%), and the most favorable texture-improved firmness, chewiness, and elasticity-while maintaining sensory acceptability close to full-fat patties. Low-field nuclear magnetic resonance (LF-NMR) and scanning electron microscopy (SEM) revealed that C-CG promoted a denser, more homogeneous gel network that effectively immobilized water. These findings demonstrate that sheepskin collagen-chitosan double-network gels are a promising and effective fat replacer for developing healthier meat products without compromising key quality attributes.

Kokumi peptides are known flavor enhancers in meat extracts and animal protein hydrolysates, but their role in bitterness modulation remains unclear. This study elucidates how the kokumi peptide γ-ELRE, derived from porcine hemoglobin, acts as a molecular stabilizer to synergistically enhance the bitterness inhibition of the meat-derived umami peptide HLQLAIR. Sensory time-intensity analysis demonstrated that while HLQLAIR alone reduced the peak bitterness of quinine from 5.00 to 3.96, its combination with γ-ELRE significantly decreased the intensity further to 3.13 (p < 0.05). In cells expressing the human bitter taste receptor hTAS2R16, treatment with γ-ELRE and HLQLAIR attenuated the salicin-induced calcium influx. γ-ELRE dose-dependently potentiated the inhibitory effect of HLQLAIR on salicin-induced Ca2+ signaling, transforming its inhibitory mode into potent non-competitive antagonism by depressing the maximal effect by approximately 49%. Molecular dynamics simulations revealed that γ-ELRE stabilized the hTAS2R16-HLQLAIR complex, significantly reducing its binding free energy (ΔGbind) by 15.8 kcal/mol. These findings unveil a novel allosteric stabilization mechanism for kokumi peptides, providing a potent, mechanism-driven strategy for developing next-generation taste modulators to improve the sensory quality of meat-derived products.

The family of elongases of very long chain fatty acids (Elovls) participate in the synthesis of PUFA, and the member Elovl6 could catalyze the elongation of palmitic acid C16:0 and palmitoleic acid C16:1 to stearic acid C18:0 and Octadecadienoic acid C18:1, which is the key rate-limiting enzyme for synthesizing PUFAs. In this study, the coding sequence of Elovl6 from Apostichopus japonicus (Aj-Elovl6) was successfully amplified, with 972 bp cDNA sequence and 674 amino acids. The phylogenetic tree and the comparison of the amino acid sequence revealed that Aj-Elovl6 exhibited high conservation within the characteristics of Elovl6, including transmembrane domains and the endoplasmic reticulum retention signal. Then Aj-Elovl6 protein was expressed by the strain of S. cerevisiae INVSC1/pYES2-Aj-Elovl6, and showed to elongate the C16:0 and C16:1 to C18:0 and C18:1. The qRT-PCR demonstrated that the Aj-Elovl6 mRNA of sea cucumber were widely distributed in various tissues and significantly up-regulated in response to Vibrio splendidus infection. When Aj- Elovl6 was inhibited by RNAi, compared with the control group, Aj-Elovl6-silenced sea cucumbers had higher mortality rates of sea cucumbers under Vibrio splendidus stress. It demonstrated that Aj-Elovl6 plays an important role in the process of immunity in sea cucumbers. And in vivo, inhibition of Aj- Elovl6 also resulted in the decrease of C18:0, C18:1 and PUFAs in sea cucumbers, which showed Aj-Elovl6 plays important role for the PUFAs elongation. At the same time, analyzation revealed that the PUFA including ARA, EPA and DHA were regulated in sea cucumbers infected by pathogenic bacteria, which was consistent with that PUFA was important for the immunity. This study demonstrated that Aj-Elovl6 plays an important role in the synthesis of PUFAs and the process of immunity in sea cucumbers by regulating the contents of PUFAs.

Consumer preferences for pork are increasingly prioritizing quality traits such as flavor and tenderness, which are often superior in Chinese indigenous pig breeds. The primary objective of this study was to explore the molecular basis of flavor traits using Rongchang (RR), Yorkshire (YY), and RR × YY (YR) breeds. The investigation focused on meat quality traits, along with untargeted metabolomics, lipidomics, and volatile flavor compound (VOC) profiling of the longissimus dorsi muscle. The results indicated that RR pork exhibited higher pH levels and overall acceptability. Analyses using electronic nose and tongue demonstrated that RR pork elicited stronger responses for W2S, W1S, and W1C sensors, as well as for umami and sourness. A total of 15 VOCs were identified as differing among the breeds. RR pork contained higher levels of benzothiazole and dimethyl sulfoxide, but lower levels of nonane, 2-methylheptane, and 2,4-dimethylheptane. Metabolomic analysis revealed 45 distinct metabolites, with a greater abundance of flavor precursors such as α-ketoglutaric acid in RR pork. Lipidomic analysis identified 22 different lipids, with triglycerides being more enriched in RR pork. Phospholipids, such as phosphatidylcholine (PC) and phosphatidylethanolamine (PE), varied by breed, with PC (e) being lowest and cardiolipin highest in RR pork. Correlation network analysis revealed that nonane, 2-methylheptane was the most connected flavor compound, positively correlating with certain lipids and metabolites, such as PC (18:1_18:1), PE (18:2e_22:6), PC (36:4) and 2-phenylglycine, and negatively correlating with PC (32:0e), SM (d41:1), N-hydroxy-2-acetamidofluorene, and histamine. This multi-omics approach provides a comprehensive view of the molecular signatures associated with pork preference, identifying potential biomarkers for meat quality that can be leveraged for future breeding strategies.

Herein, a novel flexible disulfide-bridged hyperbranched poly(amido amine)s based nonconjugated carbonized polymer dots (ssHPA-CPDs) was developed using citric acid and ssHPA with disulfide bonds as precursors. The structure and composition of ssHPA-CPDs were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, raman spectroscopy, and small-X-ray scattering. The results show that when the mass ratio of ssHPA-CPDs/citric acid is 0.5, graphite nitrogen and thiophenone/thiazole sulfur occupy a dominant position, with a higher quantum yield (29.08%). The high disulfide bond content increases ssHPA-CPDs flexibility, leading to greater surface roughness and enhanced Fe(III) binding. In addition, the fluorescence intensity of ssHPA-CPDs at 465 nm (λex = 350 nm) was used as the quantitative signal for Fe(III) detection with a limit of detection of 0.07 μM. The ssHPA-CPDs offering a rapid (1.0 min) and reproducible (three times) method by adding ascorbic acid for accurately determining Fe(III) content in liver and blood samples, with spiked recovery rates ranging from 87.47% to 106.01%. This method adopts flexible disulfide-bridged CPDs to regulate quantum yield, offering a rapid and accurate approach to detect Fe(III) content in meat by-products for the evaluation of food safety and human health.

Characteristic lipid-derived flavors in pre-prepared meat products are often diminished during reheating. This study examined how structural phase transition (SPT)-aligned preheating enhanced the generation of lipid-derived volatile compounds in cooked meat. Volatilomic analysis revealed that SPT-aligned preheating markedly reshaped the lipid-derived volatile profile of cooked Tan lamb meat, with SPT1-aligned preheating effectively enhancing the generation of hexanal, heptanal, 2-pentylfuran, octanal, 3-octanone, 1-octanol and 1-octen-3-ol. Quantitative lipidomics revealed that SPT1-aligned preheating accelerates the hydrolysis of phosphatidylcholine species containing polyunsaturated acyl chains, resulting in the accumulation of C18:2, C20:4, C22:4, C20:3, and C22:5, which are subsequently oxidized during heating to enhance lipid-derived flavor formation in cooked Tan lamb meat. Collectively, these findings illustrate a mechanistic pathway in which SPT1-aligned preheating induces phosphatidylcholine hydrolysis to enhanced generation of lipid-derived volatile compounds, providing a scientific basis for optimizing thermal interventions to improve lipid-derived volatile compounds in cooked meat.

Apples (Malus domestica) and pears (Pyrus ussuriensis) are typical climacteric fruits that mature with ethylene release, resulting in a short shelf life. Wax coating is widely used as a postharvest treatment to extend shelf life and maintain fruit quality. However, its influence on fruit storage and preservation remains insufficiently explored. In this study, apples and pears were treated with various concentrations of liquid wax. The treatment delayed color change during storage, inhibited ethylene production and respiration identity, and alleviated reductions in fruit firmness, titratable acidity, and ascorbic acid (AsA) content. An in-depth investigation was conducted on fruits treated with an 80% concentration of liquid wax. Compared with the control, wax-coated fruits exhibited a denser epidermal structure, slower chlorophyll degradation and carotenoid accumulation, and alterations in soluble sugar composition, particularly a significant reduction in sucrose content. Additionally, wax coating enhanced phenylalanine ammonia-lyase activity while reducing the activities of polyphenol oxidase, peroxidase, superoxide dismutase, and catalase. These changes in enzymatic activity inhibited the declines in total phenolic and total flavonoid contents and suppressed the accumulation of malondialdehyde, superoxide anion, and hydrogen peroxide. Quantitative real-time polymerase chain reaction analysis further indicated that wax coating altered the expression levels of genes associated with these physiological responses. Collectively, these findings suggested that wax coating formed a protective film on the fruit surface, effectively delaying ripening, preserving nutritional quality, and enhancing antioxidant capacity. This study provides novel theoretical insights into the postharvest storage and preservation of climacteric fruits.

Hemoglobin (Hb) can be employed to adjust the color of emulsion gels, thereby compensating for deficiencies in appearance and flavor when used as an animal fat substitute. However, the inherent instability of heme restricts its broader application as a food ingredient. In this study, transglutaminase-catalyzed glycosylation was applied to prepare oligochitosan-modified Hb complexes (OMHC), which were incorporated into emulsion gels to produce meat-colored oil-in-water systems. Glycosylation between oligochitosan and Hb was confirmed by polyacrylamide gel electrophoresis and validated through free amino group analysis. Increasing the oligochitosan-to-Hb ratio from 2:1 to 3:1 resulted in the highest grafting degree, reaching 41.82%. Compared with untreated Hb, OMHC significantly improved the emulsifying capacity, thermal stability, and pH stability of the emulsion gels. The effects of OMHC concentration (0, 0.3, 0.6, 1.2, and 1.8 wt%) were systematically investigated. OMHC addition increased the gel's a* value from -0.79 to 2.68 and b* value from 5.85 to 18.02, producing a natural yellowish-red hue. Rheological analysis revealed that higher OMHC concentrations elevated gelation onset temperature and enhanced gel strength, as indicated by an increase in G' at 20 °C. Fourier transform infrared spectroscopy confirmed hydrogen bonding between OMHC and gelatin, while microscopic observations demonstrated the formation of a uniform, dense gel network. These findings highlight the potential of OMHC to stabilize Hb and advance the application of meat-colored emulsion gels as saturated fat replacers in both processed meat products and plant-based alternatives.

Metabolite alterations reflect the metabolic processes that determine pork quality; however, the comprehensive profile and the dynamic evolutionary mechanisms of these metabolites remain elusive. Herein, an untargeted metabolomics methodology was established to identify key metabolites and their transformations during pork storage using GC × GC-MS coupled with bioinformatics. A total of 992 metabolites were identified, with aldehydes, acids and ketones showing significant dynamic changes. In tandem with Short Time-series Expression Miner and ANOVA analyses, we discerned six significantly enriched profiles among 285 key metabolites (p <0.05), revealing a strong correlation between pyruvate metabolism and metabolite transformations during storage. In addition, 44 discriminative metabolites were identified through partial least-squares discriminant analysis, highlighting the key role of metabolic differences among spoilage microorganisms in driving metabolite production. Bioinformatics analysis illustrated that dynamic changes in discriminative metabolites are driven by metabolic reactions, particularly enzyme-driven microbial processes and lipid oxidation. The findings offer a mechanistic understanding of metabolite transformations in refrigerated pork, predominantly driven by microbial metabolic activities, which is pivotal for future quality optimization strategies.

Anthocyanins dictate the nutritional quality of purple-fleshed sweetpotato (PFSP), yet how the lignin pathway influences anthocyanin biosynthesis and phenylpropanoid metabolic flux allocation remains largely elusive. Through integrated transcriptomic and metabolomic analyses of a purple-fleshed sweetpotato cultivar (XZ13) and its natural mutant (XZ13M), we revealed that diminished anthocyanin accumulation correlated strongly with systemic transcriptional repression of the phenylpropanoid pathway. We subsequently identified a crucial methyltransferase gene, IbCCoAOMT7, with dual nucleocytoplasmic localization. Its overexpression in its storage roots was directly associated with reduced anthocyanin accumulation and increased lignin content. Further investigations suggested that IbCCoAOMT7 was putatively involved in modulating metabolic flux toward lignin biosynthesis that downregulates the transcriptional activity of core anthocyanin biosynthetic genes. Collectively, our study highlights that IbCCoAOMT7 represents a promising candidate gene that influences the balance between the lignin and anthocyanin pathways. These findings propose a tentative regulatory model, possibly involving substrate availability and transcriptional feedback inhibition, providing precise genetic targets for breeding anthocyanin-enriched sweetpotato.

Soup is an integral component of the daily diet, however, its digestive characteristics remain unclear. In this study, the dynamic human stomach-intestine system (DHSS) was used to simulate the digestion of colloidal nanoparticles (CNPs) isolated from lamb soup through oral, gastric, and intestinal stages. The colloidal properties, morphology, and structural characteristics of CNPs were assessed using dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and Fluorescence spectroscopy (FL). The results demonstrated a progressive decline in triglyceride (TG) concentration throughout the digestion process. Aggregation and significant enlargement of CNPs were observed during the oral and gastric phases, while a notable reduction in particle size (P < 0.05) occurred during the intestinal phase, without clear boundaries. Additionally, spectroscopic analysis revealed that the CNPs’ structure underwent unfolding during digestion, exposing their clusters. Lipidomics analysis indicated variations primarily in TG and diglyceride (DG) concentrations across the oral, gastric, and intestinal digestion stages of CNPs. Furthermore, it was discovered that the main significantly different lipid molecules in the digested CNPs were up-regulated by the oral digestion simulation and down-regulated by the gastrointestinal digestion simulation (VIP >1, P < 0.05).

Congling Tibetan chicken is a geographical indication product of Chinese agricultural products. However, the effects of gender and monthly age on the chicken quality remain unclear. In this study, 4-month-old Congling Tibetan rooster (4CTR), 6-month-old Congling Tibetan rooster (6CTR) and 6-month-old Congling Tibetan hen (6CTH) were used to analyze the differences in their nutritional and lipid composition. Results indicated that 6CTH showed firmer meat with richer fatty acids and flavor compounds, while 6CTR exhibited deeper redness and higher minerals (Ca, Se, Zn). 4CTR had superior moisture and essential amino acids, but a simpler flavor. Additionally, rooster soup showed high triglycerides and diglycerides expression, while hen soup had low levels. 4CTR soup contained unique antioxidant phospholipids, while 6CTR and 6CTH soups were rich in digestible short-chain triglycerides. KEGG pathway analysis identified glycerolipid metabolism and ferroptosis as the key pathways.

BACKGROUND:Aiming to systematically assess the functional properties of collagen from livestock by-products, the present study examined the rheological properties, thermal stability and microstructure of collagen extracted from sheep, pig, cow and donkey skins. RESULTS:Sheep skin collagen exhibited a gel strength of 446.71 g, which was 2.47 times higher than that of donkey skin collagen. Differential scanning calorimetry revealed sheep skin collagen's denaturation temperature (109.61 °C) exceeded that of pig (87.92 °C), cow (62.14 °C) and donkey (96.46 °C) collagen, indicating superior thermal stability. Amino acid analysis showed sheep skin collagen contained elevated proline (176.32 g kg-1) and hydroxyproline (190.50 g kg-1) levels, reinforcing its triple-helical structure. Scanning electron microscopy confirmed sheep skin collagen's dense, interconnected fibrillar network, correlating with enhanced mechanical integrity. CONCLUSION:Sheep skin collagen exhibits exceptional physicochemical properties, making it a promising material for gel-based foods (e.g. confectionery, meat analogs) and biodegradable packaging. These findings support the sustainable utilization of livestock by-products, aligning with circular economy principles. © 2025 Society of Chemical Industry.

This study aims to elucidate the quality differences among Tan lamb from three major production regions and investigate the influence and regulation of lipids on regional sheep meat quality. The Ningxia Tan lamb exhibited higher pH values, lower lightness and yellowness, better water-holding capacity and more polyunsaturated fatty acids compared to the other regions. GC-IMS revealed different flavor profiles of Tan lamb from different regions. A total of 1080 lipids across 41 lipid subclasses were identified, with 10 lipid molecules, including PC (16:0_16:1), Carnitine C3:0 and Carnitine C5:1, serving as key differentiators among the regions, as determined by the Random Forest method. Correlation analysis revealed strong associations between acyl lipid characteristics and pH, lightness and centrifugal loss, while glycerophospholipid characteristics were significantly correlated with basic nutritional indices. Lipid metabolic pathway analysis indicated that thermogenesis, glycerophospholipid metabolism and metabolic pathways as crucial for Tan lamb growth, serving as major pathways for distinguishing different regional Tan lamb. These findings indicate that origin influences lamb quality and lipid composition and that a relationship may exist between lamb quality and lipid variations. This provides a comprehensive understanding of how lamb quality is formed and contributes to future identification of lamb origins, as well as control and enhancement of meat quality.

Understanding the relationship between thermally induced structural phase transitions (SPTs) and the formation of volatile compounds is essential for optimizing the sensory quality of meat products. Herein, lamb meat was used as a model to investigate how heat-driven SPTs modulate lipid remodeling and formation of lipid-derived volatile compounds. Differential scanning calorimetry and LF-NMR revealed three thermally induced SPTs (SPT1, SPT2, and SPT3), and hierarchical clustering confirmed strong SPT-dependent generation of lipid-derived aliphatic aldehydes. Lipidomic analysis revealed that C18:2- and C18:3-enriched triacylglycerols (TGs)/diacylglycerols (DGs) were preferentially hydrolyzed to free PUFAs, which were rapidly oxidized during SPT2-SPT3 to produce lipid-derived aliphatic aldehydes. SPT2-SPT3 was identified as the critical transition window governing the conversion of PUFAs and PUFA-containing TGs/DGs into aliphatic aldehydes during thermal processing. Overall, this study reveals how heat-induced SPTs drive lipid remodeling to regulate the formation of aliphatic aldehydes, providing mechanistic insights into flavor development in cooked meat.

The real‐time, rapid, and portable detection of food freshness is crucial for assessing food quality and ensuring food safety. Volatile amines produced during food spoilage have significant potential as markers for evaluating freshness. In this study, an electrochemical sensing platform is developed for the detection of volatile amines using gallium‐copper dual single‐atom nanozymes (with Ga and Cu contents of 1.31and 4.07 wt.%, respectively) supported by a 2D layered double hydroxide (LDH). The synergistic loading of the dual atoms facilitated binding with volatile amines, which accelerated electron transfer at the GaCu‐LDH surface, inducing changes in the electrical signals and enabling detection. The platform exhibited a rapid response time of ≈4 s, with a good linear relationship between the ammonia concentration and steady‐state current within the range of 0.05‒0.4 m m and a detection limit of 5.9 µ m . This electrochemical sensor platform enabled the rapid, portable, and intelligent detection and monitoring of the freshness of meat from livestock and poultry (pork, beef, lamb, and chicken) at room temperature and under refrigerated storage conditions, providing a valuable method for the real‐time monitoring of food freshness.