Screening And Optimization Of High Activity Esterified Strain

In this paper,the esterification of Luzhou-flavor Daqu was improved by the combined fermentation of different strains.The main contents of the paper are as follows:(1)Screening and identification of high esterification strains of Luzhou flavor Daqu.A strain with high esterification power was selected from the medium-temperature Daqu of Luzhou-flavor type by using esterase absorption and decomposition of triglyceride.(2)The koji making method of Aspergillus oryzae combined with Rhizopus oryzae was studied.By experiments,it was proved that the combined fermentation method of Aspergillus niger and Aspergillus niger was to mix Aspergillus niger and Aspergillus niger in 2:1 ratio after inoculation in the optimum fermentation medium,and the esterification force was 45.68 mg/g·100h.(3)Explore the optimization of fermentation technology of Aspergillus oryzae and Rhizopus oryzae to produce Luzhou-flavor Daqu.The effects of medium conditions and culture conditions on the esterification of Aspergillus oryzae and Rhizopus oryzae were investigated by single-factor.Plackett-Burman method was used to screen the significant factors,and it was determined that the significant factors affecting the esterification of Aspergillus arbuscularis were the initial water content,rice particle size,inoculation amount and reaction time;the significant factors affecting the esterification of Rhizoma huagen were the initial water content,the amount of olive oil added,and the reaction time.The optimum technological conditions of Aspergillus oryzae were 40 % rice,10% bran,40 % soluble starch,2 % peptone,12 % mesh rice,4 pH,12 % inoculation,144 h reaction tim e;6 % bean cake powder,40 % bran,70 % initial water content and 2 % br-an.With 5 % glucose,4 % peptone,3 % olive oil,5 pH,9 % inoculation,reaction time was 120 h.At last,the esterification force was determined to be 75.03mg/g·100h,after mixing the two curved materials at 2:1 ratio.