In this paper, to complete the global dynamics of a multi-strains SIS epidemic model, we establish a precise result on coexistence for the cases of the partial and complete duplicated multiple largest reproduction rat...In this paper, to complete the global dynamics of a multi-strains SIS epidemic model, we establish a precise result on coexistence for the cases of the partial and complete duplicated multiple largest reproduction ratios for this model.展开更多
Douchi is traditionally produced through natural fermentation without intentionally inoculated microorganisms.To improve the fermentation process,this study aimed to investigate the effects on microbiota and flavor du...Douchi is traditionally produced through natural fermentation without intentionally inoculated microorganisms.To improve the fermentation process,this study aimed to investigate the effects on microbiota and flavor during Douchi fermentation using selected autochthonous microorganisms,Bacillus amyloliquefaciens B9 and Pichia kudriavzevii Y18.Results showed that bacteria dominated the fermentation process,while fungi played a supplementary role.Genus-level analysis identified Bacillus as the most prevalent genus during fermentation,while Pichia surged on day 15 and reached peak relative abundance by day 22.During post-fermentation,the total content of volatile compounds increased by 126.91%,and the content of esters rose significantly to 1190.90μg/kg by day 30.Compared with day 0,six key volatile flavor compounds with odor activity values(OAV)exceeding 1 were newly produced,indicating that the inoculated microorganisms significantly contributed to their formation.Non-volatile metabolites exhibited varying trends,with their accumulations stabilizing in the later stages of fermentation.Notably,amino acids and dipeptides accumulated significantly during fermentation,enhancing the nutritional and flavor profiles of Douchi.The construction of the metabolic network highlighted that amino acid and carbohydrate metabolism were pivotal pathways for flavor enhancement during Douchi postfermentation.Furthermore,pyruvate and acetyl-CoA were critical in Douchi fermentation and acted as core intermediates for flavor compound production,participating in amino acid biosynthesis,the tricarboxylic acid cycle,and fatty acid biosynthesis.Additionally,Pichia played a role in the biosynthesis of γ-Aminobutyric acid.This study systematically explored the multidimensional characteristics of Douchi post-fermentation,bridging the gap between descriptive research and mechanism-driven fermentation control strategies.展开更多
文摘In this paper, to complete the global dynamics of a multi-strains SIS epidemic model, we establish a precise result on coexistence for the cases of the partial and complete duplicated multiple largest reproduction ratios for this model.
基金supported by the National Key Research and Devel-opment Program of the Ministry of Science and Technology(Project No.2022YFE0120800).
文摘Douchi is traditionally produced through natural fermentation without intentionally inoculated microorganisms.To improve the fermentation process,this study aimed to investigate the effects on microbiota and flavor during Douchi fermentation using selected autochthonous microorganisms,Bacillus amyloliquefaciens B9 and Pichia kudriavzevii Y18.Results showed that bacteria dominated the fermentation process,while fungi played a supplementary role.Genus-level analysis identified Bacillus as the most prevalent genus during fermentation,while Pichia surged on day 15 and reached peak relative abundance by day 22.During post-fermentation,the total content of volatile compounds increased by 126.91%,and the content of esters rose significantly to 1190.90μg/kg by day 30.Compared with day 0,six key volatile flavor compounds with odor activity values(OAV)exceeding 1 were newly produced,indicating that the inoculated microorganisms significantly contributed to their formation.Non-volatile metabolites exhibited varying trends,with their accumulations stabilizing in the later stages of fermentation.Notably,amino acids and dipeptides accumulated significantly during fermentation,enhancing the nutritional and flavor profiles of Douchi.The construction of the metabolic network highlighted that amino acid and carbohydrate metabolism were pivotal pathways for flavor enhancement during Douchi postfermentation.Furthermore,pyruvate and acetyl-CoA were critical in Douchi fermentation and acted as core intermediates for flavor compound production,participating in amino acid biosynthesis,the tricarboxylic acid cycle,and fatty acid biosynthesis.Additionally,Pichia played a role in the biosynthesis of γ-Aminobutyric acid.This study systematically explored the multidimensional characteristics of Douchi post-fermentation,bridging the gap between descriptive research and mechanism-driven fermentation control strategies.
