Aspergillus Type Fermentation Analysis Tempeh Fermentation And Artificial Inoculation

This study dynamically analyzed physical and chemical character, cellulose activity and protease activity, volatile components in the process of dou-chi fermentation. It showed that the number of microbe cell, acid was higher than before, amino nitrogen was higher, reducing sugar went down, fat went down, proteinase activity and cellulase activity were down to non-detected. Acid, lipid and pyrazine were increased significantly during the former and the later fermentation while macromolecular hydrocarbon and macromolecular ketone were decreased obviously. We could know that the influence of microbe affects the progress of the fermentation, and it changes the internal composition, the quality and the flavor.The microflora and compositions of Dou-chi produced by natural fermentation were ananlyzed with the observation of morphological, physiological and biochemical reaction. Maximum Likehood phylogeny tree of rDNA sequences of the6isolates sequenced and11isolates downloaded from GenBank was used to reveal the phylogenetic relationships.355U/g protease activity was showed by the Aspergillus Oryzae strain.The acidity activity of the Lactobacillus Fermentu strain was66°T.Cellulase activity and protease activity of the Bacillus Subtilis strain were47U/g and140U/g,respectively.The Staphylococcus Xylosus strain showed high ability of protein degradation.Meanwhile,a Pichia Ohmeri strain and a Aspergillus Niger were identified.In order to screen out the excellent Aspergillus oryzae strain used for producing ferment dou-chi, ultraviolet (UV) and nitrosoguanidine (NTG) were both employed to mutate the strain. The protease activity reached up to494.5U/g.The new strain was improved38%compared with the original strain and the mutant strain kept good hereditary stability. Response surface design was used to explore the effects of incubation time and incubation temperature and humidity on the producing of protease and establish a mathematic model of optimal producing of acid conditions. Results showed that the optimal modification conditions were incubation time of66.6h and incubation temperature of41.8℃and humidity of84.5%.In order to screen out the excellent Lactobacillus Fermentu strain used for producing ferment dou-chi, ultraviolet (UV) and nitrosoguanidine (NTG) were both employed to mutate the strain. The acidity reached up to68.2°T.The new strain was improved30.8%compared with the original strain and the mutant strain kept good hereditary stability. Response surface design was used to explore the effects of incubation time and incubation temperature and inoculation size on the producing of protease and establish a mathematic model of optimal producing of acid conditions. Results showed that the optimal modification conditions were incubation time of18.7h and incubation temperature of41.7℃and inoculation size of3.6%.Optimization of fermentation conditions were fomt fermentation temperature of43℃, humidity of84.5%, fermentation time of3days; later fermentation temperature of40℃, bacillus inoculation of3%(v/v), Lactobacillus inoculation of3.7%(v/v), yeast inoculation of2%(v/v).The trend of the change of microbe cell was similar between inoculated fermentation and natural fermentation. Protease activity, acidity, amino nitrogen form inoculated fermentation was more than which in natural fermentantion. The fat content form inoculated fermentation was lower than which from natural fermented. It’s more fat and alcohol flavor form inoculated fermentation than the natural fermentation. Besides, the amount of fat, alcohol, aromatic and texture, sensory evaluation significantly (P<0.05) higher than which from the natural fermentation.