The Research On Strengthening Of Maotai-flavor Daqu And Its Characteristics

Maotai-flavor Daqu is the typical high temperature Daqu. Maotai-flavor Daqu is the typical high temperature Daqu. It has the role of saccharification, fermentation and flavoring in the brewing of Maotai-flavor liquor. In this study, to take Maotai-flavor Daqu as research object, the relation among physiochemical indexes, hydrolyzing enzymes in Maotai-flavor Daqu and enzyme produced by microbial metabolism was studied. To take function microbial isolated from Maotai-flavor Daqu as research object, the strengthening effects of Maotai-flavor Daqu by the function microbial and the optimum process parameters of strengthen Daqu were studied. The applying of strengthen Daqu making by the function microbial may increase the rate of Maotaiflavor liquor of quality in the production of Maotai-flavor liquor.The physiochemical indexes and the types and activities of hydrolyzing enzymes were measured in Maotai-flavor Daqu. The results found that the physiochemical indexes of Maotai-flavor Daqu were accord with the local standards DB 52/T 871 and the main enzymes were protease, amylase and pectinase. The acid protease, neutral protease, saccharifying enzyme, cellulase, pectinase and lipase produced by 19 strains bacteria and 17 strains moulds which isolated from Maotai-flavor Daqu were determinated. Our results suggested that the hydrolyzing enzymes can potential reflect the structure and quantity of microorganisms in the Daqu.According to the capacity of producing hydrolyzing enzymes, the functional bacteria strains FBKL1.0190, FBKL1.1006, FBKL1.1012 and functional yeast strains FBKL2.0071, FBKL2.0082, FBKL2.0088 were selected. The single factor experiment ratio about solid state fermentation, the initial moisture content and training time of functional strains were studied. According to the optimum technological parameters of functional strains and production process of strengthen Daqu, the strengthen Daqu were made by using solid-state fermentation tank system.The moisture and viable number of strengthen Daqu were determinate. Our results suggested moisture of strengthen Daqu were in 30-35%, live colonies of the bacterial intensified Daqu were 109cfu/g, live colonies of the yeast intensified Daqu were 108cfu/g. The types and activities of hydrolyzing enzymes were measured in the three bacterial strains enhanced Daqu. The results verified the strain FBKL1.0190, FBKL1.1006, FBKL1.1012 had function of producing hydrolyzing enzymes. The volatile components analysis of strengthen Daqu were studied, the results suggested 2, 6-dimethyl pyrazine and 2, 3, 5 trimethyl pyrazine exit in the volatile components of strengthen Daqu making by the strain FBKL1.1006. The existence of pyrazine compounds help to highlight the style and characteristics of Maotai-flavor liquor.According to 0.1%, 0.5%, 1%, 3%, 1%, 7% and 10%, the FBKL1.1006 strain strengthen Daqu were added to the fermented grains, with the fermented grains having no strengthen Daqu as blank. After the fermentation, the sensory evaluation, microbial count, the physical and chemical indexes, the volatile components in fermented grains of the blank group and test group were determinated. The results found that the Maotai-flavor increased with the increase of the amount of the strengthening Daqu in the fermented grains in the test group. The number of bacterial and yeast colonies were 107cfu/g and 102cfu/g, the moulds cannot be found in the fermented grains. The physicochemical index analysis of fermented grains showed that the addition of intensified Daqu help to accelerate the utilization of sugar by microbes. The content of pyrazines increased along with the increasing of add the mount of intensified Daqu, when the adding amount intensified Daqu of the raw material is 5%, the content of pyrazine compounds in fermented grains were the highest which was 3.56 times than that of blank group, tetramethyl pyrazine in fermented grains was the highest which was 6.61 times than that of blank group at this time. The strain FBKL1.1006 strengthened Daqu was applied to the production of Maotai-flavor liquor, it will be conducive to enhancing the Maotai-flavor and highlight the style and characteristics of Maotai-flavor liquor.