Optimization Of Making Koji And Fermenting Conditions On The Process Of Brewing Special Millet Paste

Recently, with the improvement of our life standard and foodstuff industries, our seasoning yield has been increased a lot. And the production quality also has been developed in high rate. Various kinds of seasoning have been emerged endlessly. At the same time, variety kinds of seasoning such as new types of convenience seasoning, pure natural seasoning, complex seasoning and nutritional health protection seasoning emerge as times require. As a member of seasoning ,soy sauce contains of many nutrition ,such as protein,fat and carbohydrates. It is also a food has the function of regulating physiologically. At the process of making koji , Aspergillus oryzae have absolute superiority. Its capability has the direct effect on the quality of koji, also the quality of soy sauce product. Millet is enriching of nutrition, has high value of edible and especial function for health care. It not only has abundant of nutrimental substances just like protein, fat and carbohydrate, it is also a kind of food which can adjust the physiology of our bodies and an indispensability part of our daily life. But it also has some disadvantages, such as hard grain,poor taste,small viscous. These problems have to be solved using some kind of processing technologies. When using the Aspergillus oryzae to ferment and brewing millet paste, it can improve the millet's edible quality and the machining depth of foodstuff, accordingly product higher nutrition value and economic value.In this study, Aspergillus oryzae Y26 which was separated from millet paste produced by traditional way and then filtrated,mutated, are used to producing special millet paste through koji making and fermentation. Firstly, it is culturing the activated Aspergillus oryzae Y26 in the flask, in order to culture a large number of cells with strong ability of reproduction that can be done as seeds of koji making. It's quality have much impact on the quality of koji . In the flask, it is usually bran medium. In order to determine the expanded culturing time, this study measured the growth status of Aspergillus oryzae Y26 on the bran medium. Because of the relationship between the number of spores and growth status, this study used the statistical method of measuring the number of spores to determine cell growth conditions. In the process of making koji, Aspergillus oryzae will be experience three stages that are :absorbing water and germinating period,mycelium breeding period and spores inserting period. The third stage is period of reproducing large number of Aspergillus oryzae spores. After inoculating the Aspergillus oryzae into the flask with bran medium, determine the number of spores in different times. Then it can build up the curve of growth. The result is that the most optimal Aspergillus oryzae is the one which is cultured 60h in the bran medium.After realizing the growth status and optimal culturing time of Aspergillus oryzae in the bran medium, the study can continue to work, that is making koji. Different from the traditional way of making koji, the thalli in the koji which is made by millet is mycelium instead of spores. The process of making koji is affected by material,thalli and environment. The dealing with of the material has impact on the growth of Aspergillus oryzae and protease activity. The type of germ,quality of inoculating,the temperature and time are also very important. The optimal time of marinating and boiling time is determined by the moisture content of boiled material. The result is that the optimal marinating and boiling time are 6h and 30min. Through determining the effect of thalli type,inoculating quality,temperature and time on the protease activity , the optimal making koji conditions are ensured. Aspergillus oryzae Y26 was cultured 60h in the bran medium, and inoculated in the millet on 1%. Then made koji on the temperature of 30-35℃about 24h.At this time, the millet will be packed by mycelium and the protease activity is also very high.Fermentation period is using the protease to reduce the protein of soybean, and let the big molecule of amino acid reduced into smaller one. Amino acid is the most important element of soy sauce, also the most needed nutrition. The main process of fermentation is that mixing the soybean which is marinated,boiled,mashed, with koji on 1:1,then add the salt water into it .On the whole process of fermentation , the concentration and quantity of salt water are very important elements. After examination, the optimal operating way is that: mixed the 100g soy bean with koji made by 100g millet, then add 45g salt,25g water into the mixture. The product has fresh color ,unique,delicious taste, and the amino nitrogen content is also higher than the standard 0.4%.