Preliminary Study On Maotai-flavor Strengthened Daqu

In northern China,due to the characteristics of climate and environment,the northern region is not the core production area of Maotai-flavor liquor.In order to make up for the deficiencies caused by the climate and regional environment to make the Maotai-flavor Daqu in the North.By preparing high-quality Maotai-flavor Daqu for the production of wineries in the north,it is possible to improve the productivity and quality of the Maotai-flavor flavor liquor in the northern region.At present,a variety of functional microorganisms have been screened in the Daqu and the wine cellar of the Maotai-flavor liquor,and the functional microbes can be used to produce the strengthened Daqu to improve the quality of the Daqu.Moreover,in the current research,there is not much research on the interaction relationship between various functional microorganisms in the fermentation process of Daqu.The interaction of microorganisms in Daqu is still a stage that needs to be explored.Based on the above situation,this topic mainly makes the following studies:Firstly,two strains of Bacillus with the function of producing Maotai-flavor were selected as the starting strains,and the ability of producing Maotai-flavor was explored.Two strains of functional bacteria will be applied to the production of the strengthened Daqu,and the process of strengthening the the strengthened Daqu was determined.The physical and chemical indexes of Daqu were detected and the flavor of Daqu was analyzed by GC-MS.The results showed:the inoculated strains became the dominant bacteria groups in the strengthened Daqu,the number of which reached2.24*10~8 CFU/g.The produced starter had strong esterifying power but low saccharifying power and liquefying power.The content of pyrazine compounds in the starter was 32.8%,and the content of pyrazine reached up to 31.11%,and the content of tetramethyl pyrazine reached up to 16.365%.Secondly,the solid-state fermentation experiments of pure-species mixed yeast and Bacillus were carried out,and the mixed proportion of different functional strains was set to explore the interaction between yeast and bacillus and the effect of yeast growth on the production of beneficial metabolites.The basic physical and chemical indexes of the fermentation results of different functional strains were analyzed,and the mixed proportion with better fermentation effect was found out,and the fermentation samples were analyzed by GC-MS.The results showed that Pichia kudriavzevii FBKL 2.0008 and paste flavor producing Bacillus licheniformis FBKL1.0199 were mixed cultured.The existence of yeast did not affect the growth of bacillus,neither promoted nor inhibited,but Bacillus licheniformis was more dominant.The presence of yeast does not affect the ability of Bacillus licheniformis to produce acid protease and amylase.In addition,we tested the physicochemical indexes of the Strengthened Daqu made with different proportion of bacteria added,and found that the esterification and fermentation ability of the Strengthened Daqu with more yeast added could be improved.The results of GC-MS analysis on fermented samples with the ratio of 1:10 between bacteria and yeast showed that the percentage of pyrazines was the highest,reaching 19.268%.The percentage of tetramethyl pyrazine was 16.365%.The glucoamylase activity of several filamentous fungi preserved by our research group was detected,and a functional filamentous fungus FBKL 3.0009 with high glucoamylase production was selected.On the basis of the previous chapter,pure and mixed solid-state fermentation experiments of Absidia ramose FBKL 3.0009,Pichia kudriavzevii FBKL 2.0008 and Bacillus licheniformis FBKL 1.0199 were carried out to analyze the interaction.The results showed that the addition of fungi had no significant effect on the growth of bacteria and yeast.The activity of glucoamylase in fermentation system was related to the content of glucose and the growth and metabolism of fungi.The physicochemical indexes of the Strengthened Daqu,after fermentation were tested and the results showed that the saccharifying power of the Strengthened Daqu was improved compared with the enhanced wheat starter without adding fungi.Moreover,the saccharifying power of the fungus increased significantly with the addition of more fungus.This indicated that the addition of mould could promote the saccharifying power of the Strengthened Daqu.Finally,GC-MS analysis of flavor substances in the Strengthened Daqu showed that the addition of fungi inhibited the production of pyrazines.