Study On Pilot Plant Production Technology Of Multi - Bacteria Compound Steamed Bread

The study is based on the previous experimental results that the Saccharomyces cerevisiae(N) and Lactobacillus paracasei(G) were isolated and screened from sourdough; then Lactobacillus acidophilus(S) and Hanseula anomala(H) were added; the optimal proportion (N:G:S:H=4:2:6:1) made the steam bread of four strains was determined; the mix culture was researched through adjusting culture conditions to obtain the optimal proportion in a laboratorial stage; and the micro-ecological relation of four strains was considered in the mix culture. The study content is that the industrial medium and the technology of pilot experiment are optimized; then the preservation test and applied test of multi-microbe complex fermentation agent is conducted. Some valuable parameters are acquired in the research.The study optimized the industrial medium used orthogonal experiment, firstly. The optimal combination of medium is determined as follows:13%corn diastatic liquid, 3%bean pulp diastatic liquid,1% ammonium sulfate and 0.8%corn steep liquor, and total biomass increased to 1.0×109cfu/mL. Then, The mixed culture consisting of Saccharomyces cerevisiae, Lactobacillus paracasei, Lactobacillus acidophilus and Hanseula anomala is researched by adjusting produced technology and culture condition. After mixed culture, the proportion of four strains approaches to the aim proportion. Experimental scale is enlarged from 3L to 300L gradually. In conclusion, the condition of mixed culture is ascertained in 300L bioreactor as follows:Saccharomyces cerevisiae of 1%is firstly inoculated in the industrial medium, and cultured 7 hours at 25℃ and stirring of 60r/min at ventilation volume of 0.26vvm. In addition, Lactobacillus paracasei, Lactobacillus acidophilus and Hanseula anomala are secondly inoculated and cultured 4 hours at 35℃ and stirring of 60r/min at ventilation volume of 0.11vvm. Then continue to culture 11 hours at 25℃ and stirring of 60r/min at ventilation volume of 0.26vvm. The jar-pressure is remained at 0.05MPa to 0.06MPa. Finally, complex fermentation agent is prepared.Comparison of the quality of steamed bread with compound ferment agent attained from pilot scale experiment with the quality of steamed bread with sole yeast is described. As a result, two ferment agents do not have evident difference in shade, specific volume aspects and texture analysis. In flavor substance analysis, whereas,29 compounds are detected in the steamed bread with compound ferment agent, whereas, only 17 compounds in the steamed bread with sole yeast. The detected compounds contain mainly hydrocarbons, alcohols, esters and carbonyl compounds etc. It proves that there exist more advantages in steamed bread with compound ferment agent and the quality of steamed bread is improved significantly by compound ferment agent.