The succession pattern of bacterial communities of low-temperature Daqu during the fermentation process was analyzed using MiSeq high-throughput sequencing technology combined with multivariate statistical analysis methods,and the gene functions were annotated by PICRUSt soft-ware.The results showed that during the low-temperature Daqu fermentation process,the Chao 1 index and Shannon index of the bacterial flora sig-nificantly increased during the Shangmei and Chaohuo stages,respectively(P＜0.05).Partitioning Around Medoids(PAM)analysis showed that the samples before storage constituted cluster Ⅰ,the samples during the Shangmei,Liangmei and Qichaohuo stages constituted Cluster Ⅱ,and the samples during the Chaohuo,Dahuo,Houhuo and Yangqu stages constituted Cluster Ⅲ.The bacteria in both Cluster Ⅰ and Cluster Ⅱ samples were mainly lac-tic acid bacteria,and the cumulative average relative abundance was both＞85％.The cumulative average relative abundance of lactic acid bacteria in Cluster Ⅲ samples decreased to 61.59％,and heat-resistant bacterial groups such as Bacillus emerged,with a cumulative average relative abun-dance of 19.12％.After the Chaohuo stage,the correlation network among bacterial flora became tighter,and the distance between groups significantly decreased(P＜0.05).Gene function prediction showed that the expression levels of bacterial flora genes in cluster Ⅱ samples were significantly higher in functions related to cell growth and reproduction(P＜0.05),while in cluster Ⅲ samples,the expression levels of bacterial flora genes in function related to material metabolism were significantly higher(P＜0.05).In summary,the bacterial community structure of low-temperature Daqu underwent apparent changes during the Shangmei stage and the Chaohuo stage.After the Chaohuo stage,the interaction among bacterial communities and struc-tural stability enhanced,and the expression of genes related to substance metabolism increased.
To investigate the potential of co-fermentation with Saccharomycopsis fibuligera and Saccharomyces cerevisiae for improving the quality of Baijiu,using S.fibuligera ZJ-Y as research object,its growth characteristics and environmental tolerance were determined,and it was co-fermented with S.cerevisiae to produce Baijiu by liquid-state and solid-state fermentation.The effects of mono-strain and dual-strain fermentation on fermentation capacity,viable cell count,physicochemical indexes of the fermented grains,and volatile flavor compounds were compared.The results showed that S.fibuligera exhibited strong environmental tolerance.In liquid-state fermentation,the fermentation capacities of strains were 0.05-2.75 g/100 mL in co-fermentation group,and the alcohol content of sample was(6.70±0.12)%.In solid-state fermentation,the viable count of S.cerevisiae was 1.22×108 CFU/g in co-fermentation group,and the alcohol content of sample was(15.50±0.12)%,both of which were significantly higher than those in the mono-strain fermentation group(P<0.05).A total of 20 volatile flavor compounds were detected in fermented grains,including 6 esters,4 alcohols,4 acids,3 aldehydes,2 aromatic compounds and 1 furan.Among them,the contents of ethyl acetate and β-phenethyl alcohol were 0.421 and 0.424 mg/g in the co-fermentation group,respectively,which were extremely significantly higher than those in the mono-strain fermentation group(P<0.01).Furthermore,co-fermentation effectively reduced the contents of fused oils such as isobutanol and isoamyl alcohol.In conclusion,the co-fermentation of the two yeasts could effectively enhance fermentation efficiency and optimize the flavor profile.
Suancai,as a traditional fermented vegetable with a long history,has won the favor of consumers because of its crisp and refreshing,sour and mellow flavor,and rich nutrients such as vitamins,dietary fiber and minerals.Suancai is a fermented food which is fermented from Chinese cab-bage,mustard vegetables and green vegetables through microbial metabolism and a series of biochemical reactions.During the fermentation process,the structure of microbial community changes alternately,and the microbes in different stages plays different roles,which has a great impact on the quality,flavor and safety of Suancai.The microbial diversity of Suancai was reviewed,the effect of fermentation conditions on the quality of Suancai was discussed,and the effect of different microbial populations on the flavor formation and safety of Suancai was analyzed.The aim was to explore the feasibility of improving the quality of Suancai by regulating microbial metabolism,and to provide reference for enhancing the quality of Suancai.
In order to explore the influence mechanism between consumers'perception process of marketing information of Baijiu instant retail self-operated platform and their willingness to use,a conceptual model of consumers'willingness to use Baijiu instant retail self-operated platform was constructed based on the elaboration likelihood model(ELM).The influence mechanism of each variable on consumers'willingness to use was tested using regression analysis and Bootstrap method.The results showed that the service quality,brand image and social impact of Baijiu instant retail self-operated platform had a significant positive impact on consumers'willingness to use,while the impact of information quality and price competitiveness on consumers'willingness to use was not significant.Perceived credibility had a significant mediating effect between information quality,price competitiveness,brand image,social influence and consumers'willingness to use,but there was no mediating effect between service quality and consumers'willingness to use.The research conclusion was helpful for Baijiu instant retail platform to understand consumers'decision-making focus and optimize their resource input.
As a typical representative of China's traditional solid-state fermented distilled spirits,Baijiu's distinctive flavor and exceptional quality depend on the synergistic interactions of complex microbial communities.Recently,with the rapid advancement of multi-omics technologies,the functional potential,metabolic mechanisms,and interaction networks of microorganisms involved in Baijiu brewing have been comprehensively elucidated.In this review,the diversity characteristics of microbial communities during Baijiu brewing processes were systematically summarized,with particular emphasis placed on the mechanistic roles of core functional microbial groups in flavor compound synthesis.The metabolic pathways,functional genes,and interaction networks of microbial communities were deeply analyzed using multi-omics approaches,through which systematic regulatory mechanisms from gene expression to metabolite synthesis were revealed.In response to biosafety risks associated with open fermentation processes in Baijiu production,including exogenous contamination and the accumulation of hazardous metabolites,risk control strategies were comprehensively reviewed,ranging from raw material source control and multi-parameter monitoring during fermentation to synthetic assembly of functional microbial consortia.This review aims to provide a theoretical basis for achieving precise microbial regulation and enhancing quality and safety in Baijiu production.
