The Key Technology Research On Shortening Fermentation Period Of Chinese Cheese And Its Application

The "TangQiao" brand belonging to Sichuan TangQiao food Co., LTD has founded in xianfeng years of Qing dynasty. It has a history of more than 100 years. With its unique flavor it is known as the "special food"with PI county watercress and yongchuan fermented bean in Sichuan. But so far the processing production levels of sufu are still relatively backward and updating technology is also slow. Therefore its production mode has not already adapted to the food industry standardization and secure's development request. This study aims to the problems in sufu production,on the basic of Mucor and Rhizopus two strains, the conditions, fermentation medium and mixing ratio of them are explored and a pilot plant test is done. All the research is good for the further development of sufu production.In this topic research, first of all, the condition of Mucor producing protease is optimized. On the basis of single factor experiment of temperature, time, inoculation amount and pH value of fermentation medium,four factors three levels of the response surface method is used to analysis each significant factors and interaction. The result shows that the best cultivation condition of Mucor is temperature 27.57℃, time 68.46 h, inoculation amount 9.90%, pH value of fermentation medium 4.51, then the activity of protease can reach to 152U.Secondly, on the basic of Rhizopus, Plackett-Burman design method was used to sift three most important facters from eleven components of influcing Rhizopus producing glucoamylase such as wheat bran, peptone from casein, olive oil, bean flour,peptone, maltose, sucrose, glucose,MgSO4·7H2O,K2HPO4 and KH2PO4. The three facters are olive oil, casein peptone from casein, wheat bran. And the test also draw that reducing olive oil content and increasing peptone from casein and wheat bran content are favorable to improve the activity of glucoamylase.Then the steep hills experimental method is used to reach the center of response surface experiment, and the results show that the optimal center for olive oil is 0.04%, peptone from casein is 8.14%, wheat bran is 4.32%.Thoughout the Box-Behnken response surface method analysis, the maximum points of regression model can be obtained.When olive oil 0.01%, peptone from casein 8.14% and wheat bran4.32%,the activity of glucoamylase is 18.7 U, improving 81% than former.Moreover, Rhizopus strain was researched. On the basis of single factor experiment of temperature, time, inoculation amount and pH value of fermentation medium, four factors three levels of the response surface method is used to analysis each significant factors and interaction.The result shows that the best cultivation condition of Rhizopus producing glucoamylase activities is temperature 31.99℃, time 71.94h, inoculation amount 11.94%, pH value of fermentation medium 6.06, then the activity of glucoamylase can reach to 24.39U.Then, the mixture ratio of Mucor and Rhizopus was explored, and 1:1, 2:1, 3:1, 4:1, 5:1, 6:1 mixed volume are selected to get the answer. The results show that when testing volume ratio is 2:1, all the test results of sufu can are better. Finally, doing the pilot plant test and detecting all the indexs of sufu every month.The result shows that, spraying mixed bacteria liquid of Mucor and Rhizopus on tofu surfuce, adding meters in accessories activity, and adding 12% salt, the decting indexs of sufu such as amino acids nitrogen content can reach to 1.52 g/100g, protein content reach to 13.52 g/100g, total acid content reach to 1.04 g/100g, hardness of sufu reach to 124.6g,and coliform bacteria numbers and aflatoxin B1 content are below safe limits after five months.