Integrated metabolome and microbiome analysis reveals the effect of rumen-protected sulfur-containing amino acids on the meat quality of Tibetan sheep meat.

Introduction: This study investigated the effects of rumen-protected sulfur-containing amino acids (RPSAA) on the rumen and jejunal microbiota as well as on the metabolites and meat quality of the longissimus lumborum (LL) in Tibetan sheep. Methods: By combining 16S rDNA sequencing with UHPLC-Q-TOF MS and Pearson correlation analysis, the relationship between gastrointestinal microbiota, muscle metabolites and meat quality was identified. Results: The results showed that feeding RPSAA can increase the carcass weight, abdominal fat thickness (AP-2 group), and back fat thickness (AP-2 and AP-3 group) of Tibetan sheep. The water holding capacity (WHC), texture, and shear force (SF) of LL in the two groups also increased although the fatty acids content and brightness (L*) value significantly decreased in the AP-2 group. Metabolomics and correlation analysis further showed that RPSAA could significantly influence the metabolites in purine metabolism, thereby affecting L* and SF. In addition, RPSAA was beneficial for the fermentation of the rumen and jejunum. In both groups, the abundance of Prevotella 1, Lachnospiraceae NK3A20 group, Prevotella UCG-003, Lachnospiraceae ND3007 group in the rumen as well as the abundance of Eubacterium nodatum group and Mogibacterium group in the jejunum increased. In contrast, that of Turicibacter pathogens in the jejunum was reduced. The above microorganisms could regulate meat quality by regulating the metabolites (inosine, hypoxanthine, linoleic acid, palmitic acid, etc.) in purine and fatty acids metabolism. Discussion: Overall, reducing the levels of crude proteins in the diet and feeding RPSAA is likely to improve the carcass quality of Tibetan sheep, with the addition of RPMET (AP-2) yielding the best edible quality, possibly due to its ability to influence the gastrointestinal microbiota to subsequently regulate muscle metabolites.

The importance of supercooled stability for food during supercooling preservation: a review of mechanisms, influencing factors, and control methods.

Supercooling can preserve food in its original fresh state below its ice point temperature without freezing. However, the supercooled state is unstable in thermodynamics, state breakdown can occur at any moment, resulting in irregular and larger ice crystals formation, leading to food tissue damage, and loss of quality and nutrients. While the effectiveness of supercooling preservation has been verified in the lab and pilot scale tests, the stability of the supercooled state of food remains an open question, posing a limitation for larger industrial-scale application of supercooling preservation. Based on this background, this review presents the instability mechanisms of supercooling preservation and summarizes the factors such as food properties (e.g., material size, food components, specific surface area, and surface roughness) and preservation circumstances (e.g., cooling rate, temperature variation, and mechanical disturbance) that influence the stability of the supercooled state of food. The review also discusses novel techniques for enhancing the supercooling capacity and their limitations (e.g., precise temperature control and magnetic field). Further studies are necessary to comprehensively evaluate the effects of influence factors and supercooling technologies on supercooling, realizing the true sense of 'no-crystal' food products under subzero temperature preservation conditions in commercial applications.

Supercooling can maximize the potential of low temperature in food preservation.Supercooled state of food is unstable, with many factors affecting its stability.The quality of foodstuffs with supercooled failure is unacceptable.Instability of supercooling limits its large application in food industry.Novel technologies are developed to enhance the state stability of food supercooling.

Effect of ultrasound on keratin valorization from chicken feather waste: Process optimization and keratin characterization.

Chicken feather (CF) has been deemed as one of the main poultry byproducts with a large amount produced globally. However, the robust chemical nature of chicken feathers has been limiting in its wide-scale utilization and valorization. The study proposed a strategy of keratin regeneration from chicken feather combining ultrasound and Cysteine (Cys)-reduction for keratin regeneration. First, the ultrasonic effect on feather degradation and keratin properties was systematically explored based on Cys-reduction. Results showed that the feather dissolution was significantly improved by increasing both ultrasonic time and power, and the former had a greater impact on keratin yield. However, the treatment time over 4 h led to a decrease of keratin yield, producing more soluble peptides, > 9.7 % of which were < 0.5 kDa. Meanwhile, prolonging time decreased the thermal stability with weight loss at a lower temperature and amino acids content (e.g., Ser, Pro and Gly) of keratin. Conversely, no remarkable damage in chemical structure and thermal stability of regenerated keratin was observed by only increasing ultrasonic power, while the keratin solubility was notably promoted and reached 745.72 mg·g-1 in NaOH (0.1 M) solution (400 W, 4 h). The regenerated keratin under optimal conditions (130 W, 2.7 h, and 15 % of Cys) possessed better solubility while without obvious damage in chemical structure, thermal stability, and amino acids composition. The study illustrated that ultrasound physically improved CF degradation and keratin solubility without nature damage and provided an alternative for keratin regeneration involving no toxic reagent, probably holding promise in the utilization and valorization of feather waste.

Preparation of a cattle bone collagen peptide-calcium chelate by the ultrasound method and its structural characterization, stability analysis, and bioactivity on MC3T3-E1 cells.

This study was designed to prepare a cattle bone-derived collagen peptide-calcium chelate by the ultrasound method (CP-Ca-US), and its structure, stability, and bioactivity on MC3T3-E1 cells were characterized. Single-factor experiments optimized the preparation conditions: ultrasound power 90 W, ultrasound time 40 min, CaCl2/peptides ratio 1/2, pH 7. Under these conditions, the calcium-chelating ability reached 39.48 µg mg-1. The result of Fourier transform-infrared spectroscopy indicated that carboxyl oxygen and amino nitrogen atoms were chelation sites. Morphological analysis indicated that CP-Ca-US was characterized by a porous surface and large particles. Stability analysis demonstrated that CP-Ca-US was stable in the thermal environment and under intestinal digestion. CP-Ca-US showed more stability in gastric juice than the chelate prepared by the hydrothermal method. Cell experiments indicated that CP-Ca-US increased osteoblast proliferation (proliferation rate 153% at a concentration of 300 µg mL-1) and altered the cell cycle. Significantly, CP-Ca-US enhanced calcium absorption by interacting with calcium-sensing receptors and promoted the mineralization of MC3T3-E1 cells. This study provides the scientific basis for applying the ultrasound method to prepare peptide-calcium chelates and clarifies the positive role of chelates in bone building.

Degradation of chondroitin sulfate: Mechanism of degradation, influence factors, structure-bioactivity relationship and application.

Increasing studies focus on chondroitin sulfate (CS) degradation to improve its biological activity. The review mainly introduces the degradation methods of CS and their mechanisms. Studies have shown that different degradation methods can lead to different structures of low molecular weight chondroitin sulfate (LMCS). LMCS were prepared through ß-elimination reaction, hydrolysis reaction, hydrogen abstraction reaction, and deamination reaction. The degradation of CS is affected by two aspects: the structure of CS (disaccharide composition and molecular weight) and the influence of degradation conditions (temperature, pH, degradation promoters, auxiliary conditions, and time). LMCS with different structures have different biological activities. In addition, degradation could also change CS's metabolism, such as absorption effects and gut microbiota. Thus, choosing the appropriate degradation method for CS development and utilization is very important.

Role of Intramuscular Connective Tissue in Water Holding Capacity of Porcine Muscles.

BACKGROUND: This study evaluated the influence of intramuscular connective tissue (IMCT) on structural shrinkage and water loss during cooking. Longissimus thoracis (LT), semimembranosus (SM) and semitendinosus (ST) muscles were cut and boiled for 30 min in boiling water, followed by detection of water holding capacity (WHC), tenderness, fiber volume shrinkage and protein denaturation. RESULTS: Compared with LT and SM, ST had the best WHC and lowest WBSF and area shrinkage ratio. The mobility of immobilized water (T22) was key to holding the water of meat. ST contained the highest content of total and heat-soluble collagen. On the contrary, ST showed the lowest content of cross-links and decorin, which indicate the IMCT strength of ST is weaker than the other two. The heat-soluble collagen is positively correlated to T22. CONCLUSIONS: The shrinkage of heat-insoluble IMCT on WHC and WBSF may partly depend on the structural strength changes of IMCT components rather than solely caused by quantitative changes of IMCT.

The Investigation of Protein Profile and Meat Quality in Bovine Longissimus thoracic Frozen under Different Temperatures by Data-Independent Acquisition (DIA) Strategy.

The influence of freezing on the protein profile and quality traits in bovine Longissimus thoracic (LT) muscle was investigated by the data-independent acquisition (DIA) technique. Compared to fresh meat, a total of 262 proteins were identified as differential abundance proteins (DAPs) in four frozen groups (−12 °C, −18 °C, −38 °C, and −80 °C). According to the bioinformatics analysis, most of the DAPs in the significant Go terms and the KEGG pathway were structure proteins and enzymes. Proteome changes in the frozen bovine muscle at −12 °C and −18 °C were more significant than those at −38 °C and −80 °C. The result was consistent with the deterioration trend of the meat quality. The correlation analysis revealed that 17 proteins were correlated closely with the color, shear force, thawing loss, and cooking loss of the frozen meat, which could be used as putative biomarkers for frozen meat quality. MYO18A and ME3 are newly discovered proteins that are associated with frozen beef quality. In addition, CTTN and SERPINB6 were identified in frozen groups, which exhibited a significant inverse correlation with thawing loss (p < 0.01). These findings reveal the quality changes induced by freezing at the protein molecular level and provide new insights into the control of quality deterioration.

A sustainable and efficient recycling strategy of feather waste into keratin peptides with antimicrobial activity.

The study aimed to propose an efficient and eco-friendly strategy to improve the utilization of feather waste and converting it into high-valued antimicrobial products. Under the synergistic effect of instant catapult steam explosion (ICSE) (1.5 MPa-120 s), over 90% of chicken feather powder (CFP) was degraded into soluble peptides via keratinolysis within 3 h, about 90% of which were smaller than 3 kDa, indicating an overwhelming advantage than general proteolysis. Importantly, the keratinolysis hydrolysate of CFP was able to inhibit E. coli growth, among which the fraction < 3 kDa exhibited highest antimicrobial activity with a minimal inhibitory concentration of 30 mg/mL. Compared to other fractions, the fraction < 3 kDa contained higher content of hydrophobic amino acids (364.11 mg/g), in which about 79% of peptides had more than 60% hydrophobic ratio, potentially contributing to its antimicrobial activity. ICSE-keratinolysis process holds potential in reducing both protein resource waste and environmental pollution by valorizing feathers into antimicrobial product.

Proteomic analyses of mitochondrial damage in postmortem beef muscles.

BACKGROUND: The objective of the study was to examine the expression profiles of mitochondrial proteins in at-death and 24 h postmortem (PM) using tandem mass tag (TMT) approach to characterize the mitochondria possible mechanisms that are affiliated with tenderization. RESULTS: Results showed that the tender meat at 24 h PM emerged with more serious mitochondrial damage. Altogether 456 mitochondrial proteins were identified, including 442 down-regulated and 14 up-regulated proteins. These differentially-expressed proteins were primarily involved in the progress of PM energy metabolism, apoptosis, and the morphological alterations of mitochondrial. Among them, 47 subunits (such as NDUFA2, COX4I1, and ATP5PB) were annotated into the oxidative phosphorylation pathway. VDAC1, VDAC2, and VDAC3 involving in the damage of MPTP, and IMMT, CHCHD3, APOL and APOO modulating the morphology of mitochondria, and DIABLO and AIFM1 released from mitochondria affect caspase's activation. HSPD1 and HSPE1 involved in apoptosis, mitochondrial physiological and morphological alterations. CONCLUSION: The earlier-mentioned proteins were validated as potential indicators of tenderness regulated by mitochondrial damage. These results highlighted that mitochondrial damage possibly participate in PM tenderization of beef muscles by energy metabolism and cell apoptosis status. © 2022 Society of Chemical Industry.

An advanced strategy for efficient recycling of bovine bone: Preparing high-valued bone powder via instant catapult steam-explosion.

As the major byproduct of meat processing, bovine bone are produced in large amounts annually. However, the inefficient utilization with low-added value resulted in serious resource waste. The study aims to prepare high-value bovine bone power (BBP) via instant catapult steam-explosion (ICSE) treatment, taking ball milling (BM) method as control. Results showed that ICSE treatment deconstructed bovine bone with more holes emerging, and effectively promoted mineral dissolution and protein degradation while reduced energy consumption. Compared with BM-BBP, ICSE-BBP possessed more protein and essential minerals, presenting in regular elliptical shapes with narrow distribution of particle size (0.1 âˆ¼ 40 µm), and owned better solution stability and protein solubility. ICSE-BBP also exhibited higher mineral release and protein digestibility during GI digestion while revealed no obvious cytotoxicity, indicating the potential applicability in nutrition-fortified foods. Taken together, ICSE technology holds promise in reusing bovine bone, providing an efficient and eco-friendly process for BBP industrial production.

DIA-based quantitative proteomic analysis on the meat quality of porcine Longissimus thoracis et lumborum cooked by different procedures.

A DIA-based quantitative proteomic strategy was used to investigate the effects of different cooking procedures (steaming and boiling) on pork meat quality. Results showed that steamed meats had higher redness, cohesion, springiness, but lower lightness, yellowness, shear force, hardness, chewiness and cooking loss than boiled meats. In total of 1608 proteins were identified and 103 proteins exhibited significant difference (fold change > 1.5, P < 0.05). These DAPs mainly involved in protein structure, metabolic enzyme, protein turnover and oxidation stress. ALDOC, PVALB, PPP1R14C, AMPD1, CRYAB and SOD1 were validated as potential indicators of color variations in cooked meat. CFL1, COL1A1, COL3A1, RTN4, NRAP, NT5C3A, and SOD1 might be potential biomarker for texture changes of cooked meats. Moreover, these validated proteins exhibited significant (P < 0.05) correlation with cooking loss and could be serve as candidate predictors for cooking loss changes of meats in different cooking procedures.

Effect of Different Heat Treatments on the Quality and Flavor Compounds of Black Tibetan Sheep Meat by HS-GC-IMS Coupled with Multivariate Analysis.

There are limited reports about the effect of different heat treatments on the quality and flavor of Black Tibetan sheep meat. The current study examined the effect of pan-frying, deep-frying, baking, and boiling treatment on the quality of Black Tibetan sheep meat; the amino acid, fatty acid, and volatile flavor compounds (VFCs) were investigated by a texture analyzer, ultra-high-performance liquid chromatography (UHPLC), gas chromatography (GC), and headspace-gas chromatography-ion mobility (HS-GC-IMS). The key VFCs were identified through orthogonal partial least squares discrimination analysis (OPLS-DA), and variable importance projection (VIP) values. In addition, Pearson's correlations between meat quality parameters and key VFCs were examined. The sensory scores, including texture, color, and appearance, of baked and pan-fried meat were higher than those of deep-fried and boiled meat. The protein (40.47%) and amino acid (62.93 µmol/g) contents were the highest in pan-fried meat (p < 0.05). Additionally, it contained the highest amounts of monounsaturated and polyunsaturated fatty acids, such as oleic, linoleic, and α-linolenic acids (p < 0.05). Meanwhile, pan-fried and deep-fried meat had higher amounts of VFCs than baked meat. The OPLS-DA similarity and fingerprinting analyses revealed significant differences between the three heat treatment methods. Aldehydes were the key aroma compounds in pan-fried meat. Importantly, 3-methylbutyraldehyde and 2-heptanone contents were positively correlated with eicosenoic, oleic, isooleic, linoleic, α-Linolenic, and eicosadiene acids (p < 0.05). To sum up, pan-fried Black Tibetan sheep meat had the best edible, nutritional, and flavor quality.

Physicochemical properties, digestibility and anti-osteoporosis effect of yak bone powder with different particle sizes.

As a kind of promising resource, animal bone has been widely processed into functional foods. However, there is little research about the effect of particle size on the physicochemical properties and digestibility of yak bone powder (YBP), as well as its anti-osteoporosis activity. In this study, the YBP with median particle sizes (MPS) ranging from 19.68 to 128.37 µm were prepared, and their digestibility and anti-osteoporosis activity were investigated. The results showed that smaller MPS significantly increased water holding capacity and protein solubility without changing composition. The MPS reduction greatly promoted protein digestion, producing more peptides<3 kDa and free amino acids while decreased Ca2+ and P5+ release during gastrointestinal digestion. The in vivo results revealed the positive effect of YBP on ovariectomy-induced osteoporosis in rats. The bone mineral density of ovariectomized (OVX) rats was obviously improved by regulating bone turnover markers (B-ALP, OCN, S-CTX, ES and TRAP), thus potentially shedding light on osteoporosis remission. However, different MPS exhibited a weak effect on osteoporosis in OVX rats. Therefore, YBP could be produced in relatively large particle size without sacrificing food sensory quality, the processing time of which could also be shortened for higher productivity and lower cost.

Evaluation of volatile flavor compounds in bacon made by different pig breeds during storage time.

The oxidation and volatile constituents of bacon (which made of white pig (Duroc × Landrace × Yorkshire) and black pig (Beijing Black × Yorkshire)) during refrigerated storage were analyzed by thiobarbituric acid reactive substances (TBARS), total thiol groups, gas chromatography-mass spectrometry (GC-MS) and gas chromatography coupling with ion mobility spectrometry (GC-IMS). The TBARS value of tested samples increased while the total thiol groups decreased during 60 days storage (P < 0.05). Volatile fingerprint results were obtained by GC-MS and GC-IMS detector, the classes and contents of volatile compounds detected in WP bacon were much abundant than BP bacon. Higher phenols and acids concentrations were observed in WP bacon, while alcohols, ketones, and nitrogen-containing compounds were more determined in BP bacon. Besides, WP bacon was more notably affected by storage rather than BP bacon, and the difference of raw material is the main reason for the flavor in WP and BP bacon comparing with the storage process.

Composition of chemical elements in the edible viscera of Tibetan pigs and its correlation with environment and feed.

The main purpose of this research was to evaluate the element distribution in the edible viscera of Tibetan pigs and to clarify its correlation with soils, drinking water and feed. A total of 55 chemical elements were simultaneously quantified. P, K, Na, Mg, Ca, Fe and Zn were the most abundant elements in the analyzed viscera. The general distribution of all element concentrations in the viscera of Tibetan pigs was such that liver > kidney > small intestine > heart = lung = large intestine > stomach. Comparison with national and international allowable limits of toxic elements indicates that consumption of Tibetan pig viscera presents potential health risks. Spearman correlation analysis reveals that significantly (p < 0.0001) positive relationships exist between the element profiles of viscera and drinking water, soils as well as feed. For all edible viscera, the largest values of correlation coefficient were observed to be with corn feed. Our research provides a relatively comprehensive investigation of the elemental composition in Tibetan pig viscera. The correlation data would be helpful for the local farm to reformulate the feed for Tibetan pigs to improve the quality and safety of the viscera.

Epidemiological and clinical differences between sexes and pathogens in a three-year surveillance of acute infectious gastroenteritis in Shanghai.

Acute infectious gastroenteritis cases in Shanghai, reported over three years, were analyzed. Pathogens were identified in 1031 patients; of these, 725 and 306 were bacterial and viral cases, respectively. Vibrio parahemolyticus and Salmonella were the dominant bacteria, and Caliciviridae and Reoviridae were the dominant viral families in the local area. The acute gastroenteritis epidemic peaks appeared in August and January, which represented the active peak periods of bacteria and viruses, respectively. Logistic regression analyses with sex stratification showed that abdominal pain, fever and ingestion of unsafe food at restaurants were independent factors more frequently associated with bacterial gastroenteritis irrespective of sex; red cell-positive fecal matter was associated with bacterial gastroenteritis with an odds ratio (OR) of 3.28 only in males; and white blood cell count was associated with bacterial gastroenteritis with an OR of 1.02 only in females. Pathogen stratification showed that age, vomiting and red cell-positive fecal matter were associated with males with ORs of 0.99, 0.61 and 1.71, respectively, in bacterial gastroenteritis; and the migrant ratio was higher in males with an OR of 2.29 only in viral gastroenteritis. In conclusion, although bacterial and viral gastroenteritis shared many features, epidemiological and clinical factors differed between sexes and pathogens.

Characterization and discrimination of Tibetan and Duroc × (Landrace × Yorkshire) pork using label-free quantitative proteomics analysis.

The primary aim of this study was to unravel key proteins for the differentiation of Tibetan (n = 15) and Duroc × (Landrace × Yorkshire) (n = 15) pork. A platform consisting of LC-MS/MS analysis and label-free quantitative proteomics was utilized. Changes in the proteome profiles were observed for different pork cuts. A total of 91 and 116 differentially expressed proteins (fold change >2 or < 0.5, p-value<.05) were identified in the five cuts (e.g., shoulder, rump, loin, shank and belly) of Tibetan (TP) and Duroc × (Landrace × Yorkshire) (DLY) pork, respectively. Meanwhile, a comparative proteomics analysis was performed between the TP and DLY pork. We identified 102 expression altered proteins, of which 52.9% (n = 54) and 47.1% (n = 48) were up- and downregulated, respectively, in DLY pork compared to TP. Functional analysis of these proteins revealed that the most significantly enriched gene ontology term for the biological process was the purine-containing compound metabolic process (p = .003), while that with respect to molecular function was threonine-type peptidase activity (p = .002) and that for the cellular component was the mitochondrial inner membrane (p = .001). The most significantly enriched KEGG pathway was involved in histidine metabolism (p = .01), followed by oxidative phosphorylation (p = .02). Proteins involved in oxidative phosphorylation were overabundant in TP. Using a chemometrics approach, we identified 68 significant proteins for the discrimination of TP and DLY pork. The most significantly upregulated proteins in TP and DLY pork were nicotinamide nucleotide transhydrogenase and heat shock protein 90-beta, respectively. This study demonstrates the feasibility of using differential proteomic analysis to discriminate between TP and DLY pork, and the current dataset can be expanded to a larger sample size for possible discriminant validation.

Methicillin-resistant staphylococcus aureus isolates in a hospital of shanghai.

Methicillin-resistant Staphylococcus aureus (MRSA) strains are now common both in the health care setting and in the community. Active surveillance is critical for MRSA control and prevention. Specimens of patients (200 patients with 1119 specimens) as well as medical staff and hospital setting (1000 specimens) were randomly sampled in a level 2 hospital in Shanghai from September 2011 to August 2012. Isolation, cultivation and identification of S. aureus were performed. Totally, 67 S. aureus strains were isolated. 32 S. aureus strains were isolated from patient samples; 13 (13/32, 40.6%) of the 32 S. aureus isolates were MRSA; sputum sample and patients in the department of general internal medicine were the most frequent specimen and patient group for S. aureus strains isolation. Remaining 35 S. aureus strains were isolated from the medical staff and hospital setting; 20 (20/35, 57.1%) of the 35 S. aureus isolates were MRSA; specimens sampled from doctors and nurses' hands and nose and hospital facilities were the most frequent samples to isolate S. aureus. Resistant and virulent genes detection showed that, all 33 MRSA strains were mecA positive which accounts for 49.3% of the 67 S. aureus strains; 38 isolates were Panton-Valentine leukocidin (PVL) gene positive which accounts for 56.7% of the 67 S. aureus strains; and 17 (17/67, 25.4%) isolates are mecA and PVL genes dual positive. Multidrug-resistant strains of MRSA and PVL positive S. aureus are common in patients, medical staff and hospital setting, the potential health threat is worthy of our attention.

[Establishment and application of multiplex PCR for non-O157 H7 STEC virulence genes detection].

OBJECTIVE: Traditional detection approaches for non-O157 STEC are both time and labour consuming in diseases surveillance. Virulence genes detection based on multiplex PCR could not only improve the detection efficiency but also increase the accuracy. METHODS: Six virulence genes of non-O157:H7 (stx1, stx2, eae, hly, etpD, katP6) were detected by two groups of trebling PCRs. The multiplex PCRs were optimized by melting curve analysis in SYBR Green I real-time PCR. Testing result of multiplex PCR was consistent with serological testing. RESULTS: The sensitivity limits of the multiplex PCR for stx1, stx2, eaeP, etpD, katP, and hly were 10 ng/ml, 120 ng/ml, 110 ng/ml,165 ng/ml, 85 ng/ml, and 15 ng/ml, respectively, which is similar with that of single PCR. When the multiplex PCR was applied in 120 adults and 90 children diarrhea samples detection, 13 cases were detected for non-O157 positive. CONCLUSION: The method we established can be used for non-O157 STEC virulence genes detection and screening with high efficiency and accuracy.