Microbial fermentation is an important method to obtain antioxidant peptides.In this study,Lactobacillus par-acasei SMN-LBK was used to ferment biprotein(walnut milk)to enhance the antioxidant capacity of the active p...Microbial fermentation is an important method to obtain antioxidant peptides.In this study,Lactobacillus par-acasei SMN-LBK was used to ferment biprotein(walnut milk)to enhance the antioxidant capacity of the active peptide.The optimal fermentation process of 5%inoculum,1:7 plant protein ratio,37℃and 12 h resulted in 77.63%±0.36%DPPH scavenging,93.31%±0.25%ABTS scavenging and 79.37%±0.02%metal ion chelating capacity.The hydrolysis products were classified into three molecular weight classes using an ultra-filtration membrane system.DPAP-3 with a molecular weight of less than 3 kDa had the highest antioxidant activity.DPAP-3 was further separated into three subclasses using gel filtration chromatography.These sub-classes were characterized using nano-liquid chromatography-tandem mass spectrometry(NanoLC-MS/MS)and screened by searching https://biochemia.uwm.edu.Four antioxidant peptides were identified using a combi-nation of hydrophobic amino acids,positive ion-charge interactions,and numerical values.Two of these peptides were from animals and one from plants.Their amino acid sequences are as follows PCRGVLLR,IHIPLPRWV,QSKVLPVPQK,and KVLPVPQKA,with molecular docking binding energies of7.8,8.3,7.4,and7.7 kcal/mol,respectively.The results suggest that fermentation of plant-animal proteins with Lactobacillus paracasei can produce antioxidant peptides that can be used as functional ingredients in food products.This has the potential to conserve animal protein resources.展开更多
Biogenic amines(BAs),hazardous fermentation byproducts,necessitate effective control strategies for food safety,among which microbial remediation stands out as a promising approach.For more effective application,this ...Biogenic amines(BAs),hazardous fermentation byproducts,necessitate effective control strategies for food safety,among which microbial remediation stands out as a promising approach.For more effective application,this study elucidates the environmental drivers shaping the BAs-degradation efficacy of Lactiplantibacillus plan-tarum.BAs degradation and amine oxidase activity increased 1.46-3.97-fold and 1.77-3.76-fold at 35℃versus 20℃,with corresponding upregulation of genes involved in amine transport(potABCD)and oxidation(sufI).Although lowering the initial pH from 7 to 5 suppressed both BAs degradation and oxidase activity,pH 4 did not further suppress these processes and instead upregulated potBCD and sufI compared to neutral pH.Tran-scriptomics revealed that low-temperature stress upregulated gene expression of ribosomal proteins,cold-shock proteins and molecular chaperones.Acid stress,on the other hand,triggered ammonium accumulation and suppressed acid production.L.plantarum employs distinct adaptive strategies:suitable temperature(35℃)enhances bacterial growth and oxidase activity,while the acidic condition(pH 4)promotes nitrogenous com-pound metabolism.Therefore,targeted dual-temperature/pH control leverages these differential pathways to enhance microbial BAs biodegradation for food safety interventions.展开更多
Ferulic acid inclusion complexes(FA-HP-β-CD)effects on tyramine accumulation and gene expression of Enterobacter hormaechei MW386398 in traditional smoked horsemeat sausages were studied.Reverse transcription-quantit...Ferulic acid inclusion complexes(FA-HP-β-CD)effects on tyramine accumulation and gene expression of Enterobacter hormaechei MW386398 in traditional smoked horsemeat sausages were studied.Reverse transcription-quantitative polymerase chain reaction(RT-qPCR)was used to identify the expression of tyrosine decarboxylase(TDC)clusters in the tyramine producing pathway.In addition,relevant parameters such as microbial growth,moisture content,pH,and tyramine accumulation in pure cultures and during fermentation of smoked horsemeat sausages were evaluated.Ferulic acid(FA)and FA-HP-β-CD inclusion complexes both significantly decreased tyramine accumulation,as well as significantly inhibited tyrosine decarboxylase(tdcA)and tyrosine/tyramine antiporter(tyrP)genes expression(p<0.05).Furthermore,FA and FA-HP-β-CD inclusion complexes both reduced the number of Enterobacteriaceae in smoked horsemeat sausages,but did not alter the main microbiota.However,FA-HP-β-CD inclusion complexes exhibited stronger ability in hindering TDC related gene expression,reducing tyramine accumulation and antibacterial properties.These results indicate that FA-HP-β-CD inclusion complexes are able to reduce tyramine accumulation in smoked horsemeat sausages by inhibiting Enterobacteriaceae growth and gene expression.展开更多
This study investigated the effects of cinnamaldehyde on putrescine production by Obesumbacterium proteus in pure cultures and Xinjiang sausage.Scanning electron microscopy was used to analyze the cell morphology of t...This study investigated the effects of cinnamaldehyde on putrescine production by Obesumbacterium proteus in pure cultures and Xinjiang sausage.Scanning electron microscopy was used to analyze the cell morphology of the test bacteria,and reverse transcription real-time fluorescence quantitative polymerase chain reaction was employed to analyze the gene expression of arginine decarboxylase and ornithine decarboxylase of the test bacteria at different cinnamaldehyde concentrations.Single-molecule real-time sequencing was utilized to identify the species composition of the sausage.Moreover,relevant parameters such as putrescine accumulation and microbial growth were evaluated.The results indicated that cinnamaldehyde inhibited the growth of O.proteus by leaking its contents and changing membrane permeability,and significantly reducing putrescine accumulation by inhibiting the expression of arginine decarboxylase(adiA) and ornithine decarboxylase(speF) genes.The cinnamaldehyde concentration revealed an inverse relationship between gene expression and putrescine accumulation.Besides,cinnamaldehyde significantly reduced the abundance of harmful bacteria(Enterobacteriaceae and Pseudomonas),alleviate putrescine content and stimulate the release of amino acids in the sausage.Therefore,adding cinnamaldehyde is an effective method to inhibit putrescine accumulation and reduce the growth of spoilage microorganisms in the sausage.展开更多
This study analyzed the physicochemical indicators,bacterial community composition,biogenic amines(BAs),and free amino acids(FAAs)in Xinjiang air-dried beef.The results of bacterial community composition exhibited tha...This study analyzed the physicochemical indicators,bacterial community composition,biogenic amines(BAs),and free amino acids(FAAs)in Xinjiang air-dried beef.The results of bacterial community composition exhibited that Latilactobacillus,Paucibacter,and Leuconostoc were the dominant genera.Overall,the levels of tyramine,putrescine,and spermine were relatively high across all samples,with 20% of products containing over 100 mg/kg of tyramine.Correlation analysis revealed that 10 of the top 30 bacterial genera exhibited significant positive correlations with BAs and 12 with amino acid precursors of BAs.Among the top 10 bacterial genera,Latilactobacillus,Paucibacter,Staphylococcus,Brochothrix,and Weissella showed significant positive correlations with BAs.Latilactobacillus,Psychrobacter,Dellaglioa,and Pseudomonas are significantly positively correlated with free amino acids as biogenic amine precursors.There are sufficient precursor substances for BA formation in air-dried beef.The samples surveyed had moisture content of 55.00%-71.07%,pH of 5.00-6.00,and NaCl content of 1%-3%.These studies lay the foundation for future research on controlling BAs and improving the biosafety of air-dried beef.展开更多
Covalent complexes of bovine bone proteins(BBP)with four polyphenols(chlorogenic acid(CA),quercetin(Q),rutin(R),epigallocatechin gallate(EGCG))with were prepared to increase the high-value utilization degree of bovine...Covalent complexes of bovine bone proteins(BBP)with four polyphenols(chlorogenic acid(CA),quercetin(Q),rutin(R),epigallocatechin gallate(EGCG))with were prepared to increase the high-value utilization degree of bovine bone.The differences in coupling effect and structural and functional properties between the conjugates were also investigated.The results showed that EGCG-BBP had the highest polyphenolic equivalent at 88.05 mg/g protein and the lowest sulfhydryl group content.EGCG-BBP also had the best covalent effect.The SDS-PAGE and fluorescence spectra results revealed that the molecular weight of the conjugates increased significantly as different polyphenols conjugated with the aromatic amino acids in BBP,resulting in significant changes in the structure of EGCG-BBP.Fourier Transform infrared spectroscopy(FTIR)analysis demonstrated that the amide I band of conjugates was slightly shifted,indicating that the polyphenols were covalently bonded with BBP.Based on the results of this study and well-established mechanisms,it could be speculated that the best covalent effect of EGCG may be not only due to the eight phenolic hydroxyl groups but also to its two benzene rings,which are greatly increased in its reaction site.In terms of functional characteristics,EGCG-BBP had the highest 1-diphenyl-2-picryl-hydrazyl radical(DPPH·)scavenging capacity,while Q-BBP had the best solubility.Thus,this study provides a theoretical basis for different polyphenols’structural and functional effects on covalently modified proteins.展开更多
基金supported by the regional projects of the National Natural Fund of China(32060548,32260594)the Science and Tech-nology Innovation Talent Programme of Xinjiang Production and Construction Corps(2023CB008-04)+1 种基金the Regional Collaborative Innovation Special Project of Xinjiang Uygur Autonomous Region(2022E01028)the Guiding Science and Technology Programme of the Corps(2023ZD087).
文摘Microbial fermentation is an important method to obtain antioxidant peptides.In this study,Lactobacillus par-acasei SMN-LBK was used to ferment biprotein(walnut milk)to enhance the antioxidant capacity of the active peptide.The optimal fermentation process of 5%inoculum,1:7 plant protein ratio,37℃and 12 h resulted in 77.63%±0.36%DPPH scavenging,93.31%±0.25%ABTS scavenging and 79.37%±0.02%metal ion chelating capacity.The hydrolysis products were classified into three molecular weight classes using an ultra-filtration membrane system.DPAP-3 with a molecular weight of less than 3 kDa had the highest antioxidant activity.DPAP-3 was further separated into three subclasses using gel filtration chromatography.These sub-classes were characterized using nano-liquid chromatography-tandem mass spectrometry(NanoLC-MS/MS)and screened by searching https://biochemia.uwm.edu.Four antioxidant peptides were identified using a combi-nation of hydrophobic amino acids,positive ion-charge interactions,and numerical values.Two of these peptides were from animals and one from plants.Their amino acid sequences are as follows PCRGVLLR,IHIPLPRWV,QSKVLPVPQK,and KVLPVPQKA,with molecular docking binding energies of7.8,8.3,7.4,and7.7 kcal/mol,respectively.The results suggest that fermentation of plant-animal proteins with Lactobacillus paracasei can produce antioxidant peptides that can be used as functional ingredients in food products.This has the potential to conserve animal protein resources.
基金support from National Natural Science Foundation of China[Grant no.32272350]the Science and Technology Research Program in Key Areas of Xinjiang Production and Construction Corps[Grant no.32060547].
文摘Biogenic amines(BAs),hazardous fermentation byproducts,necessitate effective control strategies for food safety,among which microbial remediation stands out as a promising approach.For more effective application,this study elucidates the environmental drivers shaping the BAs-degradation efficacy of Lactiplantibacillus plan-tarum.BAs degradation and amine oxidase activity increased 1.46-3.97-fold and 1.77-3.76-fold at 35℃versus 20℃,with corresponding upregulation of genes involved in amine transport(potABCD)and oxidation(sufI).Although lowering the initial pH from 7 to 5 suppressed both BAs degradation and oxidase activity,pH 4 did not further suppress these processes and instead upregulated potBCD and sufI compared to neutral pH.Tran-scriptomics revealed that low-temperature stress upregulated gene expression of ribosomal proteins,cold-shock proteins and molecular chaperones.Acid stress,on the other hand,triggered ammonium accumulation and suppressed acid production.L.plantarum employs distinct adaptive strategies:suitable temperature(35℃)enhances bacterial growth and oxidase activity,while the acidic condition(pH 4)promotes nitrogenous com-pound metabolism.Therefore,targeted dual-temperature/pH control leverages these differential pathways to enhance microbial BAs biodegradation for food safety interventions.
基金This work was supported by grants from the National Natural Science Foundation of China(No.32060547)the key science and technology research projects of Xinjiang production and construction team(No.2020AB012).
文摘Ferulic acid inclusion complexes(FA-HP-β-CD)effects on tyramine accumulation and gene expression of Enterobacter hormaechei MW386398 in traditional smoked horsemeat sausages were studied.Reverse transcription-quantitative polymerase chain reaction(RT-qPCR)was used to identify the expression of tyrosine decarboxylase(TDC)clusters in the tyramine producing pathway.In addition,relevant parameters such as microbial growth,moisture content,pH,and tyramine accumulation in pure cultures and during fermentation of smoked horsemeat sausages were evaluated.Ferulic acid(FA)and FA-HP-β-CD inclusion complexes both significantly decreased tyramine accumulation,as well as significantly inhibited tyrosine decarboxylase(tdcA)and tyrosine/tyramine antiporter(tyrP)genes expression(p<0.05).Furthermore,FA and FA-HP-β-CD inclusion complexes both reduced the number of Enterobacteriaceae in smoked horsemeat sausages,but did not alter the main microbiota.However,FA-HP-β-CD inclusion complexes exhibited stronger ability in hindering TDC related gene expression,reducing tyramine accumulation and antibacterial properties.These results indicate that FA-HP-β-CD inclusion complexes are able to reduce tyramine accumulation in smoked horsemeat sausages by inhibiting Enterobacteriaceae growth and gene expression.
基金supported by the Xinjiang Production and Construction Corps(2025AB011 and 2023XM02)the National Natural Science Foundation of China(32060547)。
文摘This study investigated the effects of cinnamaldehyde on putrescine production by Obesumbacterium proteus in pure cultures and Xinjiang sausage.Scanning electron microscopy was used to analyze the cell morphology of the test bacteria,and reverse transcription real-time fluorescence quantitative polymerase chain reaction was employed to analyze the gene expression of arginine decarboxylase and ornithine decarboxylase of the test bacteria at different cinnamaldehyde concentrations.Single-molecule real-time sequencing was utilized to identify the species composition of the sausage.Moreover,relevant parameters such as putrescine accumulation and microbial growth were evaluated.The results indicated that cinnamaldehyde inhibited the growth of O.proteus by leaking its contents and changing membrane permeability,and significantly reducing putrescine accumulation by inhibiting the expression of arginine decarboxylase(adiA) and ornithine decarboxylase(speF) genes.The cinnamaldehyde concentration revealed an inverse relationship between gene expression and putrescine accumulation.Besides,cinnamaldehyde significantly reduced the abundance of harmful bacteria(Enterobacteriaceae and Pseudomonas),alleviate putrescine content and stimulate the release of amino acids in the sausage.Therefore,adding cinnamaldehyde is an effective method to inhibit putrescine accumulation and reduce the growth of spoilage microorganisms in the sausage.
基金supported by the Key research and development of the Corps,China(No.2025AB011)the National Natural Science Foundation of China(No.32560610).
文摘This study analyzed the physicochemical indicators,bacterial community composition,biogenic amines(BAs),and free amino acids(FAAs)in Xinjiang air-dried beef.The results of bacterial community composition exhibited that Latilactobacillus,Paucibacter,and Leuconostoc were the dominant genera.Overall,the levels of tyramine,putrescine,and spermine were relatively high across all samples,with 20% of products containing over 100 mg/kg of tyramine.Correlation analysis revealed that 10 of the top 30 bacterial genera exhibited significant positive correlations with BAs and 12 with amino acid precursors of BAs.Among the top 10 bacterial genera,Latilactobacillus,Paucibacter,Staphylococcus,Brochothrix,and Weissella showed significant positive correlations with BAs.Latilactobacillus,Psychrobacter,Dellaglioa,and Pseudomonas are significantly positively correlated with free amino acids as biogenic amine precursors.There are sufficient precursor substances for BA formation in air-dried beef.The samples surveyed had moisture content of 55.00%-71.07%,pH of 5.00-6.00,and NaCl content of 1%-3%.These studies lay the foundation for future research on controlling BAs and improving the biosafety of air-dried beef.
基金The authors are grateful for the financial support by Xinjiang Production and Construction Corps Scientific and Technological Research Projects(2020AB012).
文摘Covalent complexes of bovine bone proteins(BBP)with four polyphenols(chlorogenic acid(CA),quercetin(Q),rutin(R),epigallocatechin gallate(EGCG))with were prepared to increase the high-value utilization degree of bovine bone.The differences in coupling effect and structural and functional properties between the conjugates were also investigated.The results showed that EGCG-BBP had the highest polyphenolic equivalent at 88.05 mg/g protein and the lowest sulfhydryl group content.EGCG-BBP also had the best covalent effect.The SDS-PAGE and fluorescence spectra results revealed that the molecular weight of the conjugates increased significantly as different polyphenols conjugated with the aromatic amino acids in BBP,resulting in significant changes in the structure of EGCG-BBP.Fourier Transform infrared spectroscopy(FTIR)analysis demonstrated that the amide I band of conjugates was slightly shifted,indicating that the polyphenols were covalently bonded with BBP.Based on the results of this study and well-established mechanisms,it could be speculated that the best covalent effect of EGCG may be not only due to the eight phenolic hydroxyl groups but also to its two benzene rings,which are greatly increased in its reaction site.In terms of functional characteristics,EGCG-BBP had the highest 1-diphenyl-2-picryl-hydrazyl radical(DPPH·)scavenging capacity,while Q-BBP had the best solubility.Thus,this study provides a theoretical basis for different polyphenols’structural and functional effects on covalently modified proteins.
