Experimental Study On Experimental Production Of Granule Drying Of Composite Steamed Bread Starter

Multi-microbe complex fermentation agent is active bacterium agents that are used to ferment dough when steamin backing bread and other dough products.Our studying team determines the composite of bread leavening agent is Hdml-yeast(N),Hdrl-Bacterium lacticum(G),Hdr2-Bacterium lacticum(S)and Hdm2-yeast(H)mixed fermentation,and the proportion of the bread steaming agent is 4:2:6:1 in the previous study.And analysis of the changes in flavor substance produced by this ratio fermentation when ferment the dough and during steaming baking bread.Compared with active dry yeast,it has a clear advantage on the type and quantity of flavor substance.So that the complex bread leavening agent has a bright prospect.On the basis of the previous study,improving the fermentation medium,especially the sudy is foused of exploring the optimal condition of granulation and drying,and how to choose packaging materials and preservation for further study.This study inproved the original industrial culture medium through single factor experiment,determined the culture medium as follows:starch syrup 14%,peptone 3%,yeast extract 0.5%,(NH4)2SO4 1.5%,K2HPO3 0.3%?MgSO4 0.06%?MnSO4 0.02%.After four kinds of bacteria were mixed culture to determine the control method of 3 0L and 300L fermentor:the ratio of inoculation for 30L fermentation is Hdml-yeast:Hdrl-Bacterium lacticum:Hdr2-Bacterium lacticum:Hdm2-yeast is 1:10:15:1,inoculation amount was 10%of the total amount of the culture medium.Hdml-yeast was inoculated at the begining,temperature was controlled by 25?,stirring speed was controlled by 90r/min,and ventilation was controlled by 4.8vvm for 7h.Other three bacterium was inoculated turn inoculated at this time,t temperature was controlled by 35?,stirring speed was controlled by 90r/min,and ventilation was controlled by 1.5vvm for 4h,Finally,temperature was controlled by 25 ?,stirring speed was controlled by 90r/min,and ventilation was controlled by 4.8wm for 11h,and fermentor pressure was control by 0.05-0.06 MPa along.Then transfer culture fluid in 30L fermentor into 300L fermentor.Temperature was controlled by 31 ?,stirring speed was controlled by 60r/min for 7h,after 7h controlling,temperature was controlled by 25?,and stirring speed was controlled by 60r/min for 15h,and fermentor pressure was control by 0.05-0.06 MPa along.After fermentation,N:G:S:H is 4.2:2.3:7.0:1.1.Then added 52%of starch to bacterial sludge after centrifuged and mixed uniformly,and extruding into granules by twin-screw extruder granulator of a pore size of 01.0mm under the rotation speed of 140r/min.The drying process used the negative pressure fluidized bed in the study.During the experiment,determine sample moisture content under different temperature;contrast the cell survival rate before and after drying.through different product temperature,on the drying time of uninterrupted on the determination of sample moisture content in drying process and comparison of cell survival rate after drying.Then detected the rate of cell survival,and ratio of bacterium,and color,and granularity under different temperature after drying.Select the drying conditions are:controlled the drying temperature by 45? for about 30 min.The bacterial content could reaching the level of 1010 cfu/g under conditions,and the bacterias ratio were close to the ratio of the target.Finally,the PE and the foil material were compared by consulting literature,and choose the foil bag as packaging material of the complex bread leaven agent.Forecasting the shelf life by temperature accelerated test.The temperature gradient was selected as 30 ?,40 ? and 50?.Ascertain the shelf life as 6 monthes that packed by foil material.