Floral and fruity aromas are vital indicators for evaluating the quality of the sauce-flavored Baijiu,however,are hard to analyze and elucidate due to the interference of other aromas in the liquor.Herein,we developed...Floral and fruity aromas are vital indicators for evaluating the quality of the sauce-flavored Baijiu,however,are hard to analyze and elucidate due to the interference of other aromas in the liquor.Herein,we developed a pervaporation membrane separation technology(PV),that effectively reduces the complexity of analyzing floral and fruity aromas and enables the identification of key flavor compounds of the floral and fruity aromas in sauceflavored Baijiu.Contributed to the separation via PV on flavor,liquor samples differing in floral and fruity aromas are efficiently separated that allows to be sensitively analyzed by gas chromatography-ion mobility spectrometry(GC-IMS)and gas chromatography-mass spectrometry(GC-MS).We found that a total of 29 compounds that potentially contributed to floral and fruity aroma.Aroma recombination and omission/addition experiments were conducted to verify the contribution of these compounds to the overall aroma,leading to the identification of 15 key aroma compounds including affecting floral and fruity aromas.And discovered esters serving as key components for contributing floral and fruity aromas.Meanwhile,Acetals can make the aromas become more coordinated and aldehydes facilitate floral and fruity aroma release.The work contributes to a tool for elucidating complexity of flavor compounds in Baijiu.展开更多
A sensory evaluation system was established through quantitative descriptive analysis for sauce-flavored anchovy,with 13 sensory descriptor factors identified.The characteristic aroma compounds in the sauce-flavored a...A sensory evaluation system was established through quantitative descriptive analysis for sauce-flavored anchovy,with 13 sensory descriptor factors identified.The characteristic aroma compounds in the sauce-flavored anchovy were identified using solid-phase microextraction/solvent-assisted flavor evaporation-gas chromatography-mass spectrometry-olfactometry(SPME/SAFE-GC-MS-O),odor activity value(OAV)calculation,aroma extract dilution analysis(AEDA),and aroma extract concentration analysis(AECA).The results indicated that 55 volatile compounds were detected,including 31 aroma-active ones,among which nonanal,linaloolβ-myrcene,eucalyptol,eugenol,2-acetylpyrazine,anethole,and ethyl maltol(with flavor dilution factor(FD)≥81 or OAV>100)played a pivotal role in shaping the aroma profile of sauce-flavored anchovy.SPME extracted a broader and more diverse range of volatiles,with higher efficiency for highly volatile terpenoids,ketones,and furans.SAFE showed superior efficiency for aldehydes,alcohols,phenols,aromatic hydrocarbons,and highly polar compounds.2-Acetylpyrrole and benzaldehyde were just detected by AECA,likely due to losses during AEDA concentration,which demonstrated that combining the two methods lowered the risks of missing some aroma compounds.Partial least squares regression analysis(PLSR)confirmed that some volatile compounds made significant contribution to fish odor(1-octen-3-ol,nonanal,2-pentylfuran,geraniol,eugenol,anethole),braised meat aroma(eucalyptol,γ-terpinene,2-acetylpyrazine,benzaldehyde,4-ethylphenol),and spicy-pepper aroma((E,E)-2,4-decadienal,linalool,ethyl maltol).展开更多
Microbial terroir is essential to the development of regional fermented food characteristics.Environmental microbiota participates in the fermentation process and fermentation process also domesticates the microorgani...Microbial terroir is essential to the development of regional fermented food characteristics.Environmental microbiota participates in the fermentation process and fermentation process also domesticates the microorganisms in the environments,leading to an interaction between the fermentation process and the fermentation environment.Here,we reported microbiota from different environments(fermentation process,fermentation environment,and ecological environment)of two distilleries.We used amplicon full-length sequencing to study the regional microbial characteristics and the domestication of the fermentation process on environment.Fungi in the Chishui River producing region contributed more to the brewing,which contained many functional fungi,such as Pichia,Wickerhamomyces anomalus,and Debaryomyces.The fermentation process had a strong domestication effect on microbiota in the fermentation environment.Fermented grains and Daqu were the primary microbiota sources in the fermentation environment.Microorganisms in the producing area exhibited a distance decay relationship.With increasing distance from the distillery,the dissimilarity between microbial communities increased and the microbial community showed an obvious deterministic-stochastic pattern.The ecological environment 50m away from the distillery was less domesticated by the fermentation process.Abiotic factors(pH,acidity,and water content)and microbial interactions synergistically led to microbial differences across environments.These results first determined that a regional microbial model had been established in sauce-flavor Baijiu and comprehensively clarified the interaction between the fermentation process and the environment.It laid the foundation for further elucidation of the influence of microorganisms on the yield and flavor quality of sauce-flavor Baijiu.展开更多
Stacked fermentation is the process of utilizing microorganisms in the environment and further enriching their population in Jiupei.However,the composition of microbial communities in the different layers of Jiupei an...Stacked fermentation is the process of utilizing microorganisms in the environment and further enriching their population in Jiupei.However,the composition of microbial communities in the different layers of Jiupei and their relationship with sensory quality requires more clarity.This study analyzed the microbial composition of the different layers of Jiupei in the fourth round of stacked fermentation using high-throughput sequencing technology.Physicochemical properties and sensory qualities were measured;the correlation between the observed microorganisms and sensory quality was further analyzed.The results showed that there were significant differences in acidity,moisture,starch,reducing sugar,and protein content across the different layers of the Jiupei(P<0.05).The flavor substances in the entire Jiupei dump primarily included organic sulfides,terpenes,and ethanol,and umami was the most dominant taste indicator.Significant differences in microbial community structure were observed across the layers of the Jiupei,with the main bacterial genera being Thermoactinomyces(63.95%),and Bacillus(11.77%).Meanwhile,the main fungal genera identified were Pichia(28.37%),Saccharomyces(24.42%),and Byssochlamys(17.01%).The correlation between the microorganisms and the sensory indexes in Jiupei was found to be significant(P<0.05);the presence of the bacterial genera Bacillus and Thermoactinomyces and the fungal genera Saccharomyces,Byssochlamys,and Zygosaccharomyces was found to be related to the sensory quality of Jiupei.This study provides insights into the role of microorganisms in the fourth round of liquor fermentation and provides a theoretical reference for the subsequent optimization of sauce-flavor liquor quality.展开更多
Soybean paste is widely used as a seasoning for authentic Asian cuisine due to its rich and savory sauce flavor.However,the primary components of the soybean paste sauce-flavor compounds and the fermentation regulatio...Soybean paste is widely used as a seasoning for authentic Asian cuisine due to its rich and savory sauce flavor.However,the primary components of the soybean paste sauce-flavor compounds and the fermentation regulation mechanisms are still unclear.Therefore,the present study sought to systematically explore the factors affecting the sauce flavor in terms of substrate,external microorganisms,brine concentration,and the alteration in flavor composition and its regulatory mechanisms.The results of the raw material ratios showed that an appropriate increase in the proportion of soybeans(6:4)could significantly enhance the concentration of amino acid metabolites,such as 2-methylbutanal,3-methylbutanal,and 2-phenylethanal.Delayed addition to Tetragenococcus halophilic significantly enhanced 2-butylfuran,2-pentylfuran,trans-2-(2-pentenyl)furan,and sauce-flavor perception in soybean paste by modulating the total acid.A suitable brine concentration(10%)could adjust the fermentation process and facilitate the formation of benzaldehyde,2-ethylfuran,2-butylfuran,2-pentylfuran,and other sauce-flavor compounds.Meanwhile,combined results of sensory evaluation and GC-MS analysis demonstrated that the primary components of the sauce-flavor compounds in soybean paste consisted of furans(furfural,2-methylfuran,2,5-dimethylfuran,2-ethylfuran,2-butylfuran,2-pentylfuran)and pyrazine(2,6-dimethylpyrazine,3-ethyl-2,5-dimethylpyrazine).Overall,these results provide a theoretical basis for the targeted enhancement of the sauce-flavor of soybean paste and insights into the industrial production of high-quality soybean paste.展开更多
The unique style of sauce-flavor Baijiu derives from its traditional and complex multi-round fermentation process.Among them,the 2^(nd) round without additional ingredients and the 4^(th) round of fermentation that pr...The unique style of sauce-flavor Baijiu derives from its traditional and complex multi-round fermentation process.Among them,the 2^(nd) round without additional ingredients and the 4^(th) round of fermentation that produces the core sauce flavor play a crucial role in the fermentation process.However,there is still a lack of understanding and in-depth analysis of the differences the 2^(nd) and 4^(th) round fermentation in the unique brewing process of sauce-flavor Baijiu.In this study,we discovered that Lactobacillus was the predominant bacterial genus during the 2^(nd) and 4^(th) fermentation rounds,where acidity and temperature serve as primary physicochemical factors regulating microbial succession during these rounds.Variations in the abundance of yeasts,specifically Issatchenkia,and filamentous fungi,particularly Thermoascus,led to differences in flavor compounds observed between the 2^(nd) and 4^(th) round.Through GC-MS comparative analysis,the 4^(th) round exhibited a greater variety of unique characteristic flavor compounds compared to the 2^(nd) round(28>15),with more ester compounds found in the 4^(th) round.This study contributes to a deeper understanding of the rotational fermentation process in sauce-flavor Baijiu,providing new perspectives and insights.展开更多
The natural cave located on the bank of the Chishui River in Guizhou is currently the only base in the country for brewing sauce-flavor Baijiu in the cave.Utilizing the natural cave for brewing not only enriches the m...The natural cave located on the bank of the Chishui River in Guizhou is currently the only base in the country for brewing sauce-flavor Baijiu in the cave.Utilizing the natural cave for brewing not only enriches the microbial source of sauce-flavor Baijiu,but also helps in conserving land resources.This article studied the microbial communities and flavor compounds of fermented grains and the environmental microorganisms during the first and second rounds of heap fermentation in cave-brewed sauce-flavor Baijiu(CBSB).The results indicated that Thermomyces,Torulaspora,and Thermoascus were the dominant fungal genera during heap fermentation,while Virgibacillus,Kroppenstedtia,and Bacillus were the dominant bacteria.Daqu contributed 92.28%of the bacterial community and 73.89%of the fungal community to the fermented grains,while the cave air contributed 11.77%of the fungal community.During the heap fermentation process,a total of 79 volatile metabolites were identified,dominated by esters and alcohols.At the same time,134 non-volatile metabolites were detected and most amino acids content increased gradually with heap fermentation time,while flavonoids showed the opposite trend.Correlations revealed that Saccharomyces was positively correlated with a number of esters and alcohols,and that Oceanobacillus promoted the synthesis of most flavonoids and organic oxides.The study provides data parameters for the environmental microbiology of the cave and also supports the exploration of the fermentation mechanism of CBSB.展开更多
The microbial ecosystems involved in traditional food fermentation are often complex and unpredictable,posing significant challenges for quality assurance.Sauce-flavor baijiu(SFB)fermentation exemplifies a complex sol...The microbial ecosystems involved in traditional food fermentation are often complex and unpredictable,posing significant challenges for quality assurance.Sauce-flavor baijiu(SFB)fermentation exemplifies a complex solid-state process.This study investigated a bioaugmentation strategy employing two osmotolerant yeasts,Saccha-romycopsis fibuligera Y30 and Clavispora lusitaniae F13008,not only for their direct metabolic role but also for their ability to influence the broader ecological microbial community.High-throughput sequencing revealed that the inoculation significantly restructured microbial succession.The final community exhibited a unique domi-nance profile,with Saccharomyces constituting up to 69.41%of the fungal community and Lactobacillus reaching 67.21%in the bacterial community.This altered consortium enhanced substrate utilization,resulting in a 17%increase in starch breakdown and a 20%increase in total acidity compared to the control at a 30-day fermen-tation period.Metabolomic analysis indicated a substantial increase in flavor complexity,with an increase of 38.7%to 42.3%in Y30 and F13008 groups,respectively,compared to the control.Key esters,such as ethyl acetate and ethyl caproate,and alcohol like phenylethyl alcohol,were found at significantly higher concentra-tions.Integrated network analysis revealed a strong association between the engineered microbial consortia and the production of these vital flavor compounds.Our findings suggest that targeted yeast inoculation acts as a significant ecological catalyst,orchestrating extensive metabolic changes to enhance both fermentation effi-ciency and sensory quality.This strategy presents a generalizable framework for managing the microbiology of various traditional fermented foods beyond baijiu.展开更多
The fermentation temperature can directly impact biodiversity and microbial metabolism in a microbial community.Sauce-flavor Baijiu production relies on high-temperature fermentation,distinguishing it from other varie...The fermentation temperature can directly impact biodiversity and microbial metabolism in a microbial community.Sauce-flavor Baijiu production relies on high-temperature fermentation,distinguishing it from other varieties of Chinese Baijiu.However,the microbial characteristics of high-temperature pit fermentation process and the mechanisms whereby temperature influences the flavor compounds are unclear.Therefore,we investigated the succession of microbial communities,substrate consumption,and metabolite production in hightemperature fermented grains in different cellars.We also investigated the metabolic characteristics of microbial communities at different fermentation temperatures(22,30,38,and 45℃)at a small scale.The research results of fermentation in the factory’s cellar indicated that temperature was an important factor driving succession of the microbial communities from day 0 to the middle stage of pit fermentation in both traditional cellar and current modern cellar.The small-scale simulation fermentation results showed that 38℃ was optimal for the accumulation of lactic acid and ethanol in the early stage of fermentation and producing more abundant flavor substances in the subsequent stage.In conclusion,we studied the dynamic properties and microbial-succession patterns during pit fermentation at high temperatures,highlighting the significance of understanding the unique brewing mechanisms of Sauce-flavor Baijiu.展开更多
The Chishui River basin,the core production terroir for Chinese sauce-flavor baijiu,is shaped by a unique interplay between its geographical features and microbial ecology.This study investigated five typical baijiu d...The Chishui River basin,the core production terroir for Chinese sauce-flavor baijiu,is shaped by a unique interplay between its geographical features and microbial ecology.This study investigated five typical baijiu distilleries and their surrounding environments along the Chishui River by integrating high-throughput sequencing,microbial source tracking(SourceTracker),and multivariate statistical analysis.We aimed to elucidate the succession patterns of the brewing microbiome as driven by geography and its regulatory role in flavor formation.Results indicated that the microbial communities in fermented grains(jiupei)exhibited sig-nificant differentiation along an altitudinal gradient,with little significant difference observed between the river’s east and west banks at similar elevations.Fungal diversity was higher in low-to-mid altitude regions(400-600 m)(Shannon index,r=0.683,p=0.003),which were enriched with functional brewing fungi such as Aspergillus and Rhodotorula.In contrast,higher altitudes(>700 m)were less suitable for brewing due to low temperatures and hypoxia inhibiting key microbial activities.SourceTracker analysis revealed that Daqu(the fermentation starter)contributed 61.42%of the bacterial community(e.g.,Bacillus,Thermoactinomyces),serving as the primary source of saccharification.The workshop environment(e.g.,floors,tools)supplied 49.90%of the fungal community(e.g.,Pichia,Saccharomycopsis fibuligera),which dominated the fermentation process.Furthermore,core microorganisms,including Acetilactobacillus jinshanensis and Saccharomyces cerevisiae,signif-icantly influenced the accumulation of key flavor compounds(e.g.,ethyl acetate,phenylethanol)through syn-ergistic metabolism.This study unveils an’altitude-ecology-flavor’ternary coupling mechanism in the microbial geography of the Chishui River basin,providing a theoretical basis for the conservation of the region’s micro-ecology and the quality control of baijiu.展开更多
基金supported by Sichuan Province Science and Tech-nology Support Program(2022YFN0057).
文摘Floral and fruity aromas are vital indicators for evaluating the quality of the sauce-flavored Baijiu,however,are hard to analyze and elucidate due to the interference of other aromas in the liquor.Herein,we developed a pervaporation membrane separation technology(PV),that effectively reduces the complexity of analyzing floral and fruity aromas and enables the identification of key flavor compounds of the floral and fruity aromas in sauceflavored Baijiu.Contributed to the separation via PV on flavor,liquor samples differing in floral and fruity aromas are efficiently separated that allows to be sensitively analyzed by gas chromatography-ion mobility spectrometry(GC-IMS)and gas chromatography-mass spectrometry(GC-MS).We found that a total of 29 compounds that potentially contributed to floral and fruity aroma.Aroma recombination and omission/addition experiments were conducted to verify the contribution of these compounds to the overall aroma,leading to the identification of 15 key aroma compounds including affecting floral and fruity aromas.And discovered esters serving as key components for contributing floral and fruity aromas.Meanwhile,Acetals can make the aromas become more coordinated and aldehydes facilitate floral and fruity aroma release.The work contributes to a tool for elucidating complexity of flavor compounds in Baijiu.
基金funded by the Research on the Development and Application of New and Unique Sauce Flavors for Jinzi Young Fish(JZYFB2025-125)National Key R&D Program of China(2023YFD2100500)“Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province”.
文摘A sensory evaluation system was established through quantitative descriptive analysis for sauce-flavored anchovy,with 13 sensory descriptor factors identified.The characteristic aroma compounds in the sauce-flavored anchovy were identified using solid-phase microextraction/solvent-assisted flavor evaporation-gas chromatography-mass spectrometry-olfactometry(SPME/SAFE-GC-MS-O),odor activity value(OAV)calculation,aroma extract dilution analysis(AEDA),and aroma extract concentration analysis(AECA).The results indicated that 55 volatile compounds were detected,including 31 aroma-active ones,among which nonanal,linaloolβ-myrcene,eucalyptol,eugenol,2-acetylpyrazine,anethole,and ethyl maltol(with flavor dilution factor(FD)≥81 or OAV>100)played a pivotal role in shaping the aroma profile of sauce-flavored anchovy.SPME extracted a broader and more diverse range of volatiles,with higher efficiency for highly volatile terpenoids,ketones,and furans.SAFE showed superior efficiency for aldehydes,alcohols,phenols,aromatic hydrocarbons,and highly polar compounds.2-Acetylpyrrole and benzaldehyde were just detected by AECA,likely due to losses during AEDA concentration,which demonstrated that combining the two methods lowered the risks of missing some aroma compounds.Partial least squares regression analysis(PLSR)confirmed that some volatile compounds made significant contribution to fish odor(1-octen-3-ol,nonanal,2-pentylfuran,geraniol,eugenol,anethole),braised meat aroma(eucalyptol,γ-terpinene,2-acetylpyrazine,benzaldehyde,4-ethylphenol),and spicy-pepper aroma((E,E)-2,4-decadienal,linalool,ethyl maltol).
基金supported by the National Natural Science Foundation of China(32072205,22138004)Sichuan post-doctoral program.
文摘Microbial terroir is essential to the development of regional fermented food characteristics.Environmental microbiota participates in the fermentation process and fermentation process also domesticates the microorganisms in the environments,leading to an interaction between the fermentation process and the fermentation environment.Here,we reported microbiota from different environments(fermentation process,fermentation environment,and ecological environment)of two distilleries.We used amplicon full-length sequencing to study the regional microbial characteristics and the domestication of the fermentation process on environment.Fungi in the Chishui River producing region contributed more to the brewing,which contained many functional fungi,such as Pichia,Wickerhamomyces anomalus,and Debaryomyces.The fermentation process had a strong domestication effect on microbiota in the fermentation environment.Fermented grains and Daqu were the primary microbiota sources in the fermentation environment.Microorganisms in the producing area exhibited a distance decay relationship.With increasing distance from the distillery,the dissimilarity between microbial communities increased and the microbial community showed an obvious deterministic-stochastic pattern.The ecological environment 50m away from the distillery was less domesticated by the fermentation process.Abiotic factors(pH,acidity,and water content)and microbial interactions synergistically led to microbial differences across environments.These results first determined that a regional microbial model had been established in sauce-flavor Baijiu and comprehensively clarified the interaction between the fermentation process and the environment.It laid the foundation for further elucidation of the influence of microorganisms on the yield and flavor quality of sauce-flavor Baijiu.
基金supported by the Hubei Provincial Natural Science Foundation Joint Fund for Innovation and Development Project(2023AFD049)Science Foundation for Cultivation Fund for Teachers’Scientific Research Ability:“Technological Innovation Team”(2020kypytd009).
文摘Stacked fermentation is the process of utilizing microorganisms in the environment and further enriching their population in Jiupei.However,the composition of microbial communities in the different layers of Jiupei and their relationship with sensory quality requires more clarity.This study analyzed the microbial composition of the different layers of Jiupei in the fourth round of stacked fermentation using high-throughput sequencing technology.Physicochemical properties and sensory qualities were measured;the correlation between the observed microorganisms and sensory quality was further analyzed.The results showed that there were significant differences in acidity,moisture,starch,reducing sugar,and protein content across the different layers of the Jiupei(P<0.05).The flavor substances in the entire Jiupei dump primarily included organic sulfides,terpenes,and ethanol,and umami was the most dominant taste indicator.Significant differences in microbial community structure were observed across the layers of the Jiupei,with the main bacterial genera being Thermoactinomyces(63.95%),and Bacillus(11.77%).Meanwhile,the main fungal genera identified were Pichia(28.37%),Saccharomyces(24.42%),and Byssochlamys(17.01%).The correlation between the microorganisms and the sensory indexes in Jiupei was found to be significant(P<0.05);the presence of the bacterial genera Bacillus and Thermoactinomyces and the fungal genera Saccharomyces,Byssochlamys,and Zygosaccharomyces was found to be related to the sensory quality of Jiupei.This study provides insights into the role of microorganisms in the fourth round of liquor fermentation and provides a theoretical reference for the subsequent optimization of sauce-flavor liquor quality.
基金funded by the National“Twelfth Five Year”Plan for Science and Technology Support[grant number 2016YFD0401304]Tianjin Science and Technology Project[grant number 19PTSYJC00050]the project of Tianjin Science and Technology[grant numbers 20ZYJDJC00050,20YDTPJC00270].
文摘Soybean paste is widely used as a seasoning for authentic Asian cuisine due to its rich and savory sauce flavor.However,the primary components of the soybean paste sauce-flavor compounds and the fermentation regulation mechanisms are still unclear.Therefore,the present study sought to systematically explore the factors affecting the sauce flavor in terms of substrate,external microorganisms,brine concentration,and the alteration in flavor composition and its regulatory mechanisms.The results of the raw material ratios showed that an appropriate increase in the proportion of soybeans(6:4)could significantly enhance the concentration of amino acid metabolites,such as 2-methylbutanal,3-methylbutanal,and 2-phenylethanal.Delayed addition to Tetragenococcus halophilic significantly enhanced 2-butylfuran,2-pentylfuran,trans-2-(2-pentenyl)furan,and sauce-flavor perception in soybean paste by modulating the total acid.A suitable brine concentration(10%)could adjust the fermentation process and facilitate the formation of benzaldehyde,2-ethylfuran,2-butylfuran,2-pentylfuran,and other sauce-flavor compounds.Meanwhile,combined results of sensory evaluation and GC-MS analysis demonstrated that the primary components of the sauce-flavor compounds in soybean paste consisted of furans(furfural,2-methylfuran,2,5-dimethylfuran,2-ethylfuran,2-butylfuran,2-pentylfuran)and pyrazine(2,6-dimethylpyrazine,3-ethyl-2,5-dimethylpyrazine).Overall,these results provide a theoretical basis for the targeted enhancement of the sauce-flavor of soybean paste and insights into the industrial production of high-quality soybean paste.
基金support obtained from the National Natural Science Foundation of China(No.31830069).
文摘The unique style of sauce-flavor Baijiu derives from its traditional and complex multi-round fermentation process.Among them,the 2^(nd) round without additional ingredients and the 4^(th) round of fermentation that produces the core sauce flavor play a crucial role in the fermentation process.However,there is still a lack of understanding and in-depth analysis of the differences the 2^(nd) and 4^(th) round fermentation in the unique brewing process of sauce-flavor Baijiu.In this study,we discovered that Lactobacillus was the predominant bacterial genus during the 2^(nd) and 4^(th) fermentation rounds,where acidity and temperature serve as primary physicochemical factors regulating microbial succession during these rounds.Variations in the abundance of yeasts,specifically Issatchenkia,and filamentous fungi,particularly Thermoascus,led to differences in flavor compounds observed between the 2^(nd) and 4^(th) round.Through GC-MS comparative analysis,the 4^(th) round exhibited a greater variety of unique characteristic flavor compounds compared to the 2^(nd) round(28>15),with more ester compounds found in the 4^(th) round.This study contributes to a deeper understanding of the rotational fermentation process in sauce-flavor Baijiu,providing new perspectives and insights.
基金supported by the National Natural Science Foundation of China(32160554)the Guizhou Provincial Science and Technology Department Program[2022](4009006).
文摘The natural cave located on the bank of the Chishui River in Guizhou is currently the only base in the country for brewing sauce-flavor Baijiu in the cave.Utilizing the natural cave for brewing not only enriches the microbial source of sauce-flavor Baijiu,but also helps in conserving land resources.This article studied the microbial communities and flavor compounds of fermented grains and the environmental microorganisms during the first and second rounds of heap fermentation in cave-brewed sauce-flavor Baijiu(CBSB).The results indicated that Thermomyces,Torulaspora,and Thermoascus were the dominant fungal genera during heap fermentation,while Virgibacillus,Kroppenstedtia,and Bacillus were the dominant bacteria.Daqu contributed 92.28%of the bacterial community and 73.89%of the fungal community to the fermented grains,while the cave air contributed 11.77%of the fungal community.During the heap fermentation process,a total of 79 volatile metabolites were identified,dominated by esters and alcohols.At the same time,134 non-volatile metabolites were detected and most amino acids content increased gradually with heap fermentation time,while flavonoids showed the opposite trend.Correlations revealed that Saccharomyces was positively correlated with a number of esters and alcohols,and that Oceanobacillus promoted the synthesis of most flavonoids and organic oxides.The study provides data parameters for the environmental microbiology of the cave and also supports the exploration of the fermentation mechanism of CBSB.
基金supported by the National Natural Science Foundation of China(No.31830069 and 32001638)the Beijing Municipal Natural Science Foundation in conjunction with the Beijing Municipal Education Commission(No.KZ202110011016).
文摘The microbial ecosystems involved in traditional food fermentation are often complex and unpredictable,posing significant challenges for quality assurance.Sauce-flavor baijiu(SFB)fermentation exemplifies a complex solid-state process.This study investigated a bioaugmentation strategy employing two osmotolerant yeasts,Saccha-romycopsis fibuligera Y30 and Clavispora lusitaniae F13008,not only for their direct metabolic role but also for their ability to influence the broader ecological microbial community.High-throughput sequencing revealed that the inoculation significantly restructured microbial succession.The final community exhibited a unique domi-nance profile,with Saccharomyces constituting up to 69.41%of the fungal community and Lactobacillus reaching 67.21%in the bacterial community.This altered consortium enhanced substrate utilization,resulting in a 17%increase in starch breakdown and a 20%increase in total acidity compared to the control at a 30-day fermen-tation period.Metabolomic analysis indicated a substantial increase in flavor complexity,with an increase of 38.7%to 42.3%in Y30 and F13008 groups,respectively,compared to the control.Key esters,such as ethyl acetate and ethyl caproate,and alcohol like phenylethyl alcohol,were found at significantly higher concentra-tions.Integrated network analysis revealed a strong association between the engineered microbial consortia and the production of these vital flavor compounds.Our findings suggest that targeted yeast inoculation acts as a significant ecological catalyst,orchestrating extensive metabolic changes to enhance both fermentation effi-ciency and sensory quality.This strategy presents a generalizable framework for managing the microbiology of various traditional fermented foods beyond baijiu.
基金supported by the National Natural Science Foundation of China(NSFC,grant number 32201981)the National Natural Science Foundation of China(General Program,grant number 32172176).
文摘The fermentation temperature can directly impact biodiversity and microbial metabolism in a microbial community.Sauce-flavor Baijiu production relies on high-temperature fermentation,distinguishing it from other varieties of Chinese Baijiu.However,the microbial characteristics of high-temperature pit fermentation process and the mechanisms whereby temperature influences the flavor compounds are unclear.Therefore,we investigated the succession of microbial communities,substrate consumption,and metabolite production in hightemperature fermented grains in different cellars.We also investigated the metabolic characteristics of microbial communities at different fermentation temperatures(22,30,38,and 45℃)at a small scale.The research results of fermentation in the factory’s cellar indicated that temperature was an important factor driving succession of the microbial communities from day 0 to the middle stage of pit fermentation in both traditional cellar and current modern cellar.The small-scale simulation fermentation results showed that 38℃ was optimal for the accumulation of lactic acid and ethanol in the early stage of fermentation and producing more abundant flavor substances in the subsequent stage.In conclusion,we studied the dynamic properties and microbial-succession patterns during pit fermentation at high temperatures,highlighting the significance of understanding the unique brewing mechanisms of Sauce-flavor Baijiu.
基金supported by the National Natural Science Foundation of China(22138004,22422807)the Key Research and Development Program of Sichuan Province(2024YFFK0436)National Treasure Ecological Research Synergetic Innovation Center.
文摘The Chishui River basin,the core production terroir for Chinese sauce-flavor baijiu,is shaped by a unique interplay between its geographical features and microbial ecology.This study investigated five typical baijiu distilleries and their surrounding environments along the Chishui River by integrating high-throughput sequencing,microbial source tracking(SourceTracker),and multivariate statistical analysis.We aimed to elucidate the succession patterns of the brewing microbiome as driven by geography and its regulatory role in flavor formation.Results indicated that the microbial communities in fermented grains(jiupei)exhibited sig-nificant differentiation along an altitudinal gradient,with little significant difference observed between the river’s east and west banks at similar elevations.Fungal diversity was higher in low-to-mid altitude regions(400-600 m)(Shannon index,r=0.683,p=0.003),which were enriched with functional brewing fungi such as Aspergillus and Rhodotorula.In contrast,higher altitudes(>700 m)were less suitable for brewing due to low temperatures and hypoxia inhibiting key microbial activities.SourceTracker analysis revealed that Daqu(the fermentation starter)contributed 61.42%of the bacterial community(e.g.,Bacillus,Thermoactinomyces),serving as the primary source of saccharification.The workshop environment(e.g.,floors,tools)supplied 49.90%of the fungal community(e.g.,Pichia,Saccharomycopsis fibuligera),which dominated the fermentation process.Furthermore,core microorganisms,including Acetilactobacillus jinshanensis and Saccharomyces cerevisiae,signif-icantly influenced the accumulation of key flavor compounds(e.g.,ethyl acetate,phenylethanol)through syn-ergistic metabolism.This study unveils an’altitude-ecology-flavor’ternary coupling mechanism in the microbial geography of the Chishui River basin,providing a theoretical basis for the conservation of the region’s micro-ecology and the quality control of baijiu.
