Study On The Application Of Fresh Bamboo In The Brewing Of Qing-flavor Daqu Baijiu

In order to reduce the odor caused by the bran to the baijiu and increase the unique flavor component of the bamboo,this thesis uses the fresh bamboo instead of the clam shell as the auxiliary material to brew Qing-flavor Daqu Baijiu.The optimal fermentation process parameters were obtained by response surface optimization.High-throughput sequencing technology was used to study the microbial community structure succession during the fermentation of Qing-flavor Daqu Baijiu of bamboo instead of bran,and compared with traditional Qing-flavor Daqu Baijiu.Then,using headspace solid phase microextraction?HS-SPME?combined with gas chromatography-mass spectrometry?GC-MS?to compare and analyze the volatile flavor components of traditional Qing-flavor Daqu Baijiu and Qing-flavor Daqu Baijiu of bamboo instead of bran,and compare the common bamboo and Qing-flavor Daqu Baijiu of bamboo instead of bran ingredient.The main research contents and results are as follows:?1?Fermentation process research.The peak value of each fermentation process was determined by single factor test:fresh bamboo addition?accounting for the percentage of excipients?50%,fresh bamboo comminution 2 to 3 mm²,auxiliary materials?accounting for the original grain percentage?15%.According to the results of single factor test,fresh bamboo addition?%of auxiliary materials?,fresh bamboo crushing degree,auxiliary material dosage?%of raw grain?were used as independent variables,and the wine yield was the response value.The Box-Behnken response surface method was used to optimize the fermentation process.Determine the optimal fermentation process parameters:fresh bamboo added amount of 47.65%,fresh bamboo crushing degree of 2.71mm2,auxiliary material dosage of 15.03%,and the wine yield was 37.10±0.41%.?2?To explore the succession law and comparative analysis of microbial community structure of K?Qing-flavor Daqu Baijiu secondly brewed?and Z?Qing-flavor Daqu Baijiu secondly brewed of bamboo instead of bran?.The results showed that fresh bamboo replaced the bran for the brewing of fragrant Qing-flavor Daqu Baijiu,which enriched the microbial community diversity in the wine cellar and had a great influence on the microbial community structure succession law.The dominant bacteria in the fermentation process of Z?relative abundance>1%?:Kroppenstedtia,LactoBacillus,VirgiBacillus,Weissella,Staphylococcus,Thermoactinomyces,Pediococcus,Burkholderia,Leuconostoc;dominant fungi?relative abundance>1%?:Saccharomyces,Aspergillus,Candida,Thermomyces,Thermoascus,unclassified_Saccharomycetales,Rhizopus.The bacteria with significant difference?p<0.05?in the fermentation process of K and Z have the FalsiBacillus,Pseudocitrobacter,Kroppenstedtia,the fungus Thermoscus,Microascus.?3?Using headspace solid phase microextraction?HS-SPME?and gas chromatography-mass spectrometry?GC-MS?,fresh bamboo,K₁?Qing-flavor Daqu Baijiu firstly brewed?and K₂?Qing-flavor Daqu Baijiu secondly brewed?were detected.The wine has two flavors of wine,Z₁?Qing-flavor Daqu Baijiu firstly brewed of bamboo instead of bran?,Z₂?Qing-flavor Daqu Baijiu secondly brewed of bamboo instead of bran?volatile flavor components,and comparative analysis.A total of 22 species of K₁ volatile flavor components were detected,and 35species were detected by Z₁;18 species of K₂ volatile flavor components were detected,and 32 species were detected by Z₂.The results showed that fresh bamboo as an auxiliary part to replace the clam shell enriched the volatile flavor components of liquor.Through professional sensory evaluation,it was found that the white wine with fresh bamboo has obvious bamboo fragrance,which indicates that the addition of fresh bamboo can increase the unique fragrance of the bamboo.2-Methylnaphthalene is a characteristic flavor component of fresh bamboo and Z1.There are seven kinds of common components of fresh bamboo and Z2:ethyl lactate,ethyl citrate,ethyl laurate,ethyl decanoate,ethyl myristate,ethyl pentadecanoate,and isoamyl alcohol.However,all of the seven components were detected in K₂,so it cannot be said that these seven components are unique components brought into the wine by fresh bamboo.However,combined with sensory evaluation,Z₂ has obvious bamboo fragrance,indicating that fresh bamboo instead of clam shell may undergo physical or chemical changes in the fermentation process to produce different intermediate metabolites or end products,thus affecting the volatile flavor components of the wine.