The Analysis Of The Main Indicators In Production Process Of Changsha Stinky Tofu

Stinky tofu is a traditional food of China with a long history, there is a large of historical record from the ancient indigenous to the Ming and Qing dynasties. At present, the production technology of stinky tofu mainly adopts "open fermentation", conditions of crude production plant for more than 1 year of natural fermentation time, there is no process control, nor control standards for fermentation degree of brine, the immersion degree and time also completely depend on experience, there is no theoretical basis. Let the quality of stinky tofu is difficult to control. This article through different fermentation stages of brine to determine microbial colony, flavor substances testing, physical and chemical index analysis, to monitor the whole fermentation process of brine, trying to build a set of standards about the end of different stages stinky tofu fermentation, to make the production of stinky tofu tend to be more standardized, promote the development of industrialization of stinky tofu, improve the influence of the changsha stinky tofu.1. Through the determination of different stages of microbial colony in Brine, in addition to spore bacteria because of its strong environmental adaptability, other microbes are showing a downward trend along with the fermentation, this change in addition to the brine salinity, pH value and so on, with competition between species, bacteria in mutual competition. Based on microbial pure culture and 454 high throughput analysis of two different brine can be found that number of spore bacteria in the fermentation process is stable, difference of the rest in the different phase is very big, the early is given priority to bacteria and enterobacteriaceae, the late is given priority to spore fungus and bacteria.2. Based on the research of the flavor substances in different stage of brine, it can be found that aldehydes, acids, alcohols, alkanes and esters etc., will be to appear different degree of change as fermentation. Among them, by comparing the volatile constituents between combination of fermented black beans and mushrooms, found the highest levels of ester (33.03%), alkanes (21.62%), acid (20.19%), pyrazine (12.96%), and mushrooms with the 6-11 kinds of alcohols,3-6 kinds of ketone,2 kinds of phenolics were has played a critical role on volatile components in the process of brine fermentation. Ketone substance and sulfur impurity alkanes mainly comes from mushrooms, alkanes substance and esters mainly comes from liuyang lobster sauce.And other low odor composition in brine, the content in liuyang spicy fermented black beans and mushrooms is the same.3. Through the research on the physical and chemical properties of different stage of brine, the protein content reduced to 0.27% from 1.29% initially, amino acid nitrogen reduced from the original 0.29% to 0.05%, this is because the result of microbial metabolism. And salinity increased from 0.42% to 1.25% shows that salt is as indispensable raw material to add in food fermentation, and nitrite increased from 0.068 mg/Kg to 70 mg/Kg, this rapid growth shows that no necessary regulation for nitrite control in the process of brine fermentation, it is related to raw materials were chosen. pH value increased from the original 5.78 to 7.44 and then stable gradually, this kind of change with the participation of lactic acid bacteria are also associated with flavor components.And the iron content in brine has not too big change, is stable at 10 mg/Kg.4. Through the research on physical and chemical indicators of stinky tofu before and after Fring, nitrite reduced from the original 70 mg/Kg to 1.05 mg/Kg, with residue 1.5%, stinky tofu billet after soaked by water washing can reduce the content of nitrite and there is no obvious change after fring; In contrast, content of iron appeared a higher growth rate after fring, the finished product from 9.54 mg/Kg in brine to 131.81 mg/Kg in stinky tofu billet and then to 338.64 mg/Kg after Fring. Because of the process of ferrous sulfate coloring, content of Fe in Stinky tofu billet increased, and after frying, the content of Fe is also increased, in addition to the change of stinky tofu itself form. For the odor composition, they have more common material, but there are many ingredients appeared different degree of change can be found in the comparison of before and after fring, that high temperature and oxidation in the process of Fried indeed have a certain influence on the odor composition composition of stinky tofu.