Brewer’s spent grain(BSG)and brewer’s spent yeast(BSY)are two major brewing by-products,which are low-cost raw materials with high yields and nutritional value.In this study,the antioxidant peptides from brewing by-...Brewer’s spent grain(BSG)and brewer’s spent yeast(BSY)are two major brewing by-products,which are low-cost raw materials with high yields and nutritional value.In this study,the antioxidant peptides from brewing by-products were separated,purified and identified by UF,GFC or HIC,semi-preparative RP-HPLC,and nano-HPLC-MS/MS.Thereafter,in silico analysis was applied to predict the bioactivity,toxicity,and bioavailability of the identified peptides,and a total of 23 potential novel peptides with antioxidant activity and bioavailability were excavated.Furthermore,molecular docking results revealed the potential antioxidant peptides had stable binding ability to Keap1,and Tyr334,Arg380,Arg415,Arg483,and Tyr525 residues contributed enormously to docking,all of which were located in the binding sites of Keap1-Nrf2 interaction.Peptides with the lowest binding energy(i.e.AGRLPW,DRLW,KPW,PLWWRHPR,RVWNPFR,and ANLPWLGK)were further synthesized and validated in vitro and at the cellular level to be bioactive.Western blot results showed that KPW,RVWNPFR,and ANLPWLGK could protect HaCaT cells from H_(2)O_(2)-induced oxidative damage by activating Keap1-Nrf2 pathway.These findings provided insights into the high value-added utilization of brewing by-products.展开更多
Raw-materials based broad bean paste(rmBBP)is popular among consumers.Though high salinity can select functional microbial community for fermentation,it also impaired the fermentation efficiency of rmBBP and unfavored...Raw-materials based broad bean paste(rmBBP)is popular among consumers.Though high salinity can select functional microbial community for fermentation,it also impaired the fermentation efficiency of rmBBP and unfavored human health.Therefore,this study aimed to construct a synthetic microbial community based on key functional microbes for reduced salt rmBBP fermentation based on the elucidation of the microbial community succession during fermentation.Based on the tracked determination and multivariate statistical analysis of the physicochemical parameters,metabolites and the structure of microbial community,salinity and microbial in-teractions were key drivers for the succession of microbial community.Aspergillus,Staphylococcus,Weissella and Tetragenococcus were predicted to play key roles during fermentation.After that,core species were isolated from rmBBP mash and their salinity tolerance and metabolic characteristics were evaluated.Finally,a synthetic mi-crobial community(Aspergillus oryzae,Staphylococcus carnosus,Tetragenococcus halophilus and Weissella confusa)was constructed and applied in reduced-salt rmBBP fermentation.The bioaugmentation contributed to the accumulation of volatile metabolites while effectively maintaining the acidity during rmBBP fermentation when salinity was reduced from 12%to 10%.In general,this study developed a synthetic microbial community with desired characteristics for successful reduced-salinity rmBBP fermentation.展开更多
This study aimed to obtain an Aspergillus oryzae strain with high protease activity and to evaluate its potential to apply as starter culture in bean-based fermented foods(BBFFs)production using doubanjiang fermentati...This study aimed to obtain an Aspergillus oryzae strain with high protease activity and to evaluate its potential to apply as starter culture in bean-based fermented foods(BBFFs)production using doubanjiang fermentation as research model.A.oryzae BL18 with higher protease activity than the commonly used starter A.oryzae 3.042 was obtained through two rounds of screening.Moreover,this strain was also proved to be safe to apply in BBFFs fermentation due to the lack of the ability to produce aflatoxin B1 through genomic and experimental analysis.A.oryzae BL18 was optimal to grow under 0-12%salinity,25-40℃ and pH4-6.During koji-making,A.oryzae BL18 had stronger ability to produce spores(4.19×10^(8)spores/g dry weight)and to secrete protease(4654.35 U/g)than A.oryzae 3.042(2.89×10^(8)spores/g dry weight and 3604.40 U/g).Significantly higher concentrations of umami amino acids and volatile flavor compounds were found in doubanjiang fermentation inoculated by A.oryzae BL18 while better sensory characteristics were observed.Therefore,A.oryzae BL18 might be a promising starter to apply in fermentation of doubanjiang or other BBFFs.展开更多
This study aimed to elaborate the contributions of sunlight-expose process and core-microbiota metabolism on improving the Doubanjiang flavor profile.Four Doubanjiang fermentation models were designed with sunlight-ex...This study aimed to elaborate the contributions of sunlight-expose process and core-microbiota metabolism on improving the Doubanjiang flavor profile.Four Doubanjiang fermentation models were designed with sunlight-expose and core-microbiota metabolism as independent variable.It was found that the synergism of sunlight-expose and core taxa metabolism was favorable to improve the diversity of volatile and non-volatile compounds during Doubanjiang fermentation,a total of 49 VOCs were screened to characterize this effect contributed by sunlight and core taxa.The contribution for core-microbiota metabolism to flavor profile reached 71.3%,which was much higher than that of sunlight-expose process(28.6%),Additionally,the proportion of Staphylococcus(31.9%)and Zygosaccharomyces(21.9%)is more prominent to flavor profile among 4 core microorganisms after RDA analysis,and the environment with light-expose was beneficial to promote the growth of A.oryzae,S.carnosus and Z.rouxii.The situ fermentation was conducted to further verify the role of sunlight-expose,Z.rouxii and S.carnosus in improving the Doubanjiang flavor profile.This study was conducive to reveal the scientific mechanism behind the traditional Doubanjiang fermentation,and provide the new insight to Doubanjiang brewing technology.展开更多
This study aimed to reveal the effect of salt reduction on the nutritional,functional and sensory aspects of doubanjiang through preparing three sets of doubanjiang fermentation(Sample H,Sample M and Sample L)with dif...This study aimed to reveal the effect of salt reduction on the nutritional,functional and sensory aspects of doubanjiang through preparing three sets of doubanjiang fermentation(Sample H,Sample M and Sample L)with different salt concentrations.The results showed that fermentation with lower salt concentration led to significantly higher amino acids concentrations in doubanjiang,while the organic acids concentrations were also slightly increased.For biologically active compounds,the concentrations of total flavonoids,total phenols and five monomer isoflavones in Sample L were all significantly higher than those in Sample M and Sample H.Moreover,better anti-oxidant ability was observed in doubanjiang samples fermented with lower salt concentration.Bacillus and Millerozyma genus were found to be closely related to the formation of amino acids and biologically active compounds in doubanjiang,while organic acids were highly correlated with Cronobacter,Erwinia,Trabulsiella,Enterobacter and Millerozyma genus.Through sensory evaluation and electric tongue,unsatisfactory sensory characteristics,such as lighter color,strong acid taste and off-flavor,were found in lower salt fermented doubanjiang samples.This indicated that lower salt concentration favored the nutrition and function of doubanjiang while negatively influenced doubanjiang flavor.This study deepened our understanding of the roles of salt concentration on doubanjiang fermentation and provided guidance for the further development of low-salt doubanjiang.展开更多
Zygosaccharomyces rouxii(Z.rouxii)and Staphylococcus carnosus(S.carnosus)are fundamental taxa in spontaneous bean-based food fermentation,playing a vital role in flavor generation and macromolecule degradation.The pre...Zygosaccharomyces rouxii(Z.rouxii)and Staphylococcus carnosus(S.carnosus)are fundamental taxa in spontaneous bean-based food fermentation,playing a vital role in flavor generation and macromolecule degradation.The present study aimed to investigate the biological mechanisms underlying the interaction between Z.rouxii Y-8 and S.carnosus M43 in BBP(broad bean paste)moromi by mono-and co-culture.It was found that the biomass of Z.rouxii and S.carnosus was higher in co-culture than that in mono-culture(p<0.05),indicating that a facilitation relationship among them.Moreover,the observed intensity of facilitation(OIF)peaked at 0.479±0.002 under aerobic conditions,which was higher than that under anaerobic conditions(0.147±0.014).Furthermore,the facilitative microbial interaction showed the stability and robustness during co-culture with different inoculum proportions(1:3,1:5,1:7,1:10)and cell passage from 1 to 4 generations.Physical separation co-culture and acetic acid tolerance test revealed that acetic acid played a crucial role in regulating the interaction between Z.rouxii(R^(2)=0.6955)and S.carnosus(R^(2)=0.7097),with metabolic complementarity and inhibition alleviation as the underlying mechanisms.Additionally,Z.rouxii and S.carnosus as starter could enhance the accumulation of flavor compound,and accelerate the maturity of BBP fermentation.The dissection of interaction between Z.rouxii and S.carnosus provided valuable insights for revealing the complex web of relationships among microbiota and the development of microbial starter in BBP brewing ecosystem.展开更多
This study aimed to enhance the acidic activity of proteolytic enzymes produced by B.amyloliquefaciens BS5582 and reveal their application effect in soy sauce fermentation.Through ARTP mutagenesis,a B3 mutant strain w...This study aimed to enhance the acidic activity of proteolytic enzymes produced by B.amyloliquefaciens BS5582 and reveal their application effect in soy sauce fermentation.Through ARTP mutagenesis,a B3 mutant strain with 277 U/mL activity under pH5.0 was obtained,which was 45.03%higher than that in BS5582.Moreover,the optimal pH of proteolytic enzymes from B3 mutant strain was decreased from pH7.5 to pH6.0 while it also displayed good stability under pH5.0-7.5.The proteolytic enzymes from B3 mutant strain also showed stronger high salinity tolerance ability since its half-life value(18.4 days)under 14%salinity was significantly longer than that in BS5582(14.4 days).The genome resequencing and RT-qPCR results showed that the up-regulated expression of acidic peptidase bpr gene was closely related to the enhancement of acidic enzymatic activity.After application in soy sauce fermentation,the concentrations of amino acid nitrogen and free amino acids in soy sauce with addition of B3 enzymes(0.85 g/100g and 2.77 g/100g)were 18.06%and 32.54%higher than those in blank,which were also better than those of BS5582 enzymes and commercial enzyme.Furthermore,the addition of B3 enzymes significantly improved the quantity and concentration of volatile flavor compounds with higher sensory evaluation scores for taste and aroma in soy sauce.The results obtained in this study showed that the proteolytic enzymes from B3 mutant strain had great potential application value in soy sauce fermentation.展开更多
Ribonucleic acid(RNA)and its degradation products find widespread application across various industries,including the food condiments sector.This study employed comparative transcriptomics to investigate the genetic m...Ribonucleic acid(RNA)and its degradation products find widespread application across various industries,including the food condiments sector.This study employed comparative transcriptomics to investigate the genetic mechanisms underlying RNA synthesis in the mutant Saccharomyces pastorianus strain G03H8,which exhibited a high RNA yield.To identify genetically engineered targets,single gene over-expression and CRISPR/Cas9 gene editing technology were utilized.The differential enrichment results revealed a close association between RNA metabolism and cellular processes such as the cell cycle,purine metabolism,nucleotide metabolism,and other metabolic pathways.Subsequently,we selected the top nine most promising genes to evaluate their impact on RNA synthesis.In these nine targets,upon comparing the RNA yield of the genetically engineered strains,G03-TAL1,G03-PGM2,G03-ΔPRS5,and G03-△DBP8,with the parent strain G03,significant improvements of 31.7%,41.8%,72.1%,and 46.7%were observed,respectively.Furthermore,these four genes were found to enhance the strain’s growth and augment the pentose phosphate pathway,thus demonstrating the considerable potential for enhancing RNA yield.Notably,this study represents the first instance of identifying the upregulation of TAL1,PGM2,PRS5,and DBP8 as a means to increase RNA content in S.pastorianus.Consequently,our findings present novel genetic targets for enhancing RNA production and contribute to a deeper understanding of the mechanisms involved in high RNA synthesis in S.pastorianus.展开更多
基金financially supported by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions,China and Program of Introducing Talents of Discipline to Universities,China(No.111-2-06)the National High-tech Research and Development Program 863,China(No.2018YFD0400403)National Natural Science Foundation,China(31771963,31901626).
文摘Brewer’s spent grain(BSG)and brewer’s spent yeast(BSY)are two major brewing by-products,which are low-cost raw materials with high yields and nutritional value.In this study,the antioxidant peptides from brewing by-products were separated,purified and identified by UF,GFC or HIC,semi-preparative RP-HPLC,and nano-HPLC-MS/MS.Thereafter,in silico analysis was applied to predict the bioactivity,toxicity,and bioavailability of the identified peptides,and a total of 23 potential novel peptides with antioxidant activity and bioavailability were excavated.Furthermore,molecular docking results revealed the potential antioxidant peptides had stable binding ability to Keap1,and Tyr334,Arg380,Arg415,Arg483,and Tyr525 residues contributed enormously to docking,all of which were located in the binding sites of Keap1-Nrf2 interaction.Peptides with the lowest binding energy(i.e.AGRLPW,DRLW,KPW,PLWWRHPR,RVWNPFR,and ANLPWLGK)were further synthesized and validated in vitro and at the cellular level to be bioactive.Western blot results showed that KPW,RVWNPFR,and ANLPWLGK could protect HaCaT cells from H_(2)O_(2)-induced oxidative damage by activating Keap1-Nrf2 pathway.These findings provided insights into the high value-added utilization of brewing by-products.
基金supported by the National Natural Science Foundation of China(No.32272282)Yunnan Province Science and Technology department(No.202305AF150007)Key Laboratory of Industrial Biotechnology of Ministry of Education in Jiangnan Univer-sity(No.KLIB-KF202208).
文摘Raw-materials based broad bean paste(rmBBP)is popular among consumers.Though high salinity can select functional microbial community for fermentation,it also impaired the fermentation efficiency of rmBBP and unfavored human health.Therefore,this study aimed to construct a synthetic microbial community based on key functional microbes for reduced salt rmBBP fermentation based on the elucidation of the microbial community succession during fermentation.Based on the tracked determination and multivariate statistical analysis of the physicochemical parameters,metabolites and the structure of microbial community,salinity and microbial in-teractions were key drivers for the succession of microbial community.Aspergillus,Staphylococcus,Weissella and Tetragenococcus were predicted to play key roles during fermentation.After that,core species were isolated from rmBBP mash and their salinity tolerance and metabolic characteristics were evaluated.Finally,a synthetic mi-crobial community(Aspergillus oryzae,Staphylococcus carnosus,Tetragenococcus halophilus and Weissella confusa)was constructed and applied in reduced-salt rmBBP fermentation.The bioaugmentation contributed to the accumulation of volatile metabolites while effectively maintaining the acidity during rmBBP fermentation when salinity was reduced from 12%to 10%.In general,this study developed a synthetic microbial community with desired characteristics for successful reduced-salinity rmBBP fermentation.
基金supported by the funding of National Natural Science Foundation(No.32272282)National Key R&D Program of China(No.2018YFD0400403)Key Laboratory of Industrial Biotechnology and Ministry of Education(No.KLIB-KF202104).
文摘This study aimed to obtain an Aspergillus oryzae strain with high protease activity and to evaluate its potential to apply as starter culture in bean-based fermented foods(BBFFs)production using doubanjiang fermentation as research model.A.oryzae BL18 with higher protease activity than the commonly used starter A.oryzae 3.042 was obtained through two rounds of screening.Moreover,this strain was also proved to be safe to apply in BBFFs fermentation due to the lack of the ability to produce aflatoxin B1 through genomic and experimental analysis.A.oryzae BL18 was optimal to grow under 0-12%salinity,25-40℃ and pH4-6.During koji-making,A.oryzae BL18 had stronger ability to produce spores(4.19×10^(8)spores/g dry weight)and to secrete protease(4654.35 U/g)than A.oryzae 3.042(2.89×10^(8)spores/g dry weight and 3604.40 U/g).Significantly higher concentrations of umami amino acids and volatile flavor compounds were found in doubanjiang fermentation inoculated by A.oryzae BL18 while better sensory characteristics were observed.Therefore,A.oryzae BL18 might be a promising starter to apply in fermentation of doubanjiang or other BBFFs.
基金financially supported by National Natural Science Foundation(No.32272282)Key Laboratory of Industrial Biotechnology,Ministry of Education(No.KLIB-KF202104)+1 种基金Program of Introducing Talents of Discipline to Universities(No.111-2-06)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX22_2366).
文摘This study aimed to elaborate the contributions of sunlight-expose process and core-microbiota metabolism on improving the Doubanjiang flavor profile.Four Doubanjiang fermentation models were designed with sunlight-expose and core-microbiota metabolism as independent variable.It was found that the synergism of sunlight-expose and core taxa metabolism was favorable to improve the diversity of volatile and non-volatile compounds during Doubanjiang fermentation,a total of 49 VOCs were screened to characterize this effect contributed by sunlight and core taxa.The contribution for core-microbiota metabolism to flavor profile reached 71.3%,which was much higher than that of sunlight-expose process(28.6%),Additionally,the proportion of Staphylococcus(31.9%)and Zygosaccharomyces(21.9%)is more prominent to flavor profile among 4 core microorganisms after RDA analysis,and the environment with light-expose was beneficial to promote the growth of A.oryzae,S.carnosus and Z.rouxii.The situ fermentation was conducted to further verify the role of sunlight-expose,Z.rouxii and S.carnosus in improving the Doubanjiang flavor profile.This study was conducive to reveal the scientific mechanism behind the traditional Doubanjiang fermentation,and provide the new insight to Doubanjiang brewing technology.
基金This study was financially supported by the funding of Key Laboratory of Industrial Biotechnology,Ministry of Education(KLIB-KF202104)National Key R&D Program of China(No.2018YFD0400403)Program of Introducing Talents of Discipline to Universities(No.111-2-06).
文摘This study aimed to reveal the effect of salt reduction on the nutritional,functional and sensory aspects of doubanjiang through preparing three sets of doubanjiang fermentation(Sample H,Sample M and Sample L)with different salt concentrations.The results showed that fermentation with lower salt concentration led to significantly higher amino acids concentrations in doubanjiang,while the organic acids concentrations were also slightly increased.For biologically active compounds,the concentrations of total flavonoids,total phenols and five monomer isoflavones in Sample L were all significantly higher than those in Sample M and Sample H.Moreover,better anti-oxidant ability was observed in doubanjiang samples fermented with lower salt concentration.Bacillus and Millerozyma genus were found to be closely related to the formation of amino acids and biologically active compounds in doubanjiang,while organic acids were highly correlated with Cronobacter,Erwinia,Trabulsiella,Enterobacter and Millerozyma genus.Through sensory evaluation and electric tongue,unsatisfactory sensory characteristics,such as lighter color,strong acid taste and off-flavor,were found in lower salt fermented doubanjiang samples.This indicated that lower salt concentration favored the nutrition and function of doubanjiang while negatively influenced doubanjiang flavor.This study deepened our understanding of the roles of salt concentration on doubanjiang fermentation and provided guidance for the further development of low-salt doubanjiang.
基金financially supported by National Natural Science Foundation(No.32272282)Key Laboratory of Industrial Biotechnology,Ministry of Education(No.KLIB-KF202104)+1 种基金Program of Introducing Talents of Discipline to Universities(No.111-2-06)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX22_2366).
文摘Zygosaccharomyces rouxii(Z.rouxii)and Staphylococcus carnosus(S.carnosus)are fundamental taxa in spontaneous bean-based food fermentation,playing a vital role in flavor generation and macromolecule degradation.The present study aimed to investigate the biological mechanisms underlying the interaction between Z.rouxii Y-8 and S.carnosus M43 in BBP(broad bean paste)moromi by mono-and co-culture.It was found that the biomass of Z.rouxii and S.carnosus was higher in co-culture than that in mono-culture(p<0.05),indicating that a facilitation relationship among them.Moreover,the observed intensity of facilitation(OIF)peaked at 0.479±0.002 under aerobic conditions,which was higher than that under anaerobic conditions(0.147±0.014).Furthermore,the facilitative microbial interaction showed the stability and robustness during co-culture with different inoculum proportions(1:3,1:5,1:7,1:10)and cell passage from 1 to 4 generations.Physical separation co-culture and acetic acid tolerance test revealed that acetic acid played a crucial role in regulating the interaction between Z.rouxii(R^(2)=0.6955)and S.carnosus(R^(2)=0.7097),with metabolic complementarity and inhibition alleviation as the underlying mechanisms.Additionally,Z.rouxii and S.carnosus as starter could enhance the accumulation of flavor compound,and accelerate the maturity of BBP fermentation.The dissection of interaction between Z.rouxii and S.carnosus provided valuable insights for revealing the complex web of relationships among microbiota and the development of microbial starter in BBP brewing ecosystem.
基金financially supported by the National Natural Science Foundation of China(No.32472294 and No.32272282).
文摘This study aimed to enhance the acidic activity of proteolytic enzymes produced by B.amyloliquefaciens BS5582 and reveal their application effect in soy sauce fermentation.Through ARTP mutagenesis,a B3 mutant strain with 277 U/mL activity under pH5.0 was obtained,which was 45.03%higher than that in BS5582.Moreover,the optimal pH of proteolytic enzymes from B3 mutant strain was decreased from pH7.5 to pH6.0 while it also displayed good stability under pH5.0-7.5.The proteolytic enzymes from B3 mutant strain also showed stronger high salinity tolerance ability since its half-life value(18.4 days)under 14%salinity was significantly longer than that in BS5582(14.4 days).The genome resequencing and RT-qPCR results showed that the up-regulated expression of acidic peptidase bpr gene was closely related to the enhancement of acidic enzymatic activity.After application in soy sauce fermentation,the concentrations of amino acid nitrogen and free amino acids in soy sauce with addition of B3 enzymes(0.85 g/100g and 2.77 g/100g)were 18.06%and 32.54%higher than those in blank,which were also better than those of BS5582 enzymes and commercial enzyme.Furthermore,the addition of B3 enzymes significantly improved the quantity and concentration of volatile flavor compounds with higher sensory evaluation scores for taste and aroma in soy sauce.The results obtained in this study showed that the proteolytic enzymes from B3 mutant strain had great potential application value in soy sauce fermentation.
基金founded by the National Science Foundation(No.31571942,No.31601558&No.31771963)the Program of Introducing Talents of Discipline to Universities(No.111-2-06).
文摘Ribonucleic acid(RNA)and its degradation products find widespread application across various industries,including the food condiments sector.This study employed comparative transcriptomics to investigate the genetic mechanisms underlying RNA synthesis in the mutant Saccharomyces pastorianus strain G03H8,which exhibited a high RNA yield.To identify genetically engineered targets,single gene over-expression and CRISPR/Cas9 gene editing technology were utilized.The differential enrichment results revealed a close association between RNA metabolism and cellular processes such as the cell cycle,purine metabolism,nucleotide metabolism,and other metabolic pathways.Subsequently,we selected the top nine most promising genes to evaluate their impact on RNA synthesis.In these nine targets,upon comparing the RNA yield of the genetically engineered strains,G03-TAL1,G03-PGM2,G03-ΔPRS5,and G03-△DBP8,with the parent strain G03,significant improvements of 31.7%,41.8%,72.1%,and 46.7%were observed,respectively.Furthermore,these four genes were found to enhance the strain’s growth and augment the pentose phosphate pathway,thus demonstrating the considerable potential for enhancing RNA yield.Notably,this study represents the first instance of identifying the upregulation of TAL1,PGM2,PRS5,and DBP8 as a means to increase RNA content in S.pastorianus.Consequently,our findings present novel genetic targets for enhancing RNA production and contribute to a deeper understanding of the mechanisms involved in high RNA synthesis in S.pastorianus.
