Study On The Fermentation Of Light-flavor Douchi And The Drying Processing Of Light-flavor Douchi Powder

Light-flavor Douchi is a sub-category of tempeh, it is a traditional Chinese medicine and overcome the shortcomings of high oil and high salt. Light-flavor Douchi has a wealth of health function. In this study, China Rhizopus 12 was selected to ferment the Light-flavor Douchi. The optimal fermentation conditions of the black beans light-flavor Douchi after 48 hours of germination treatment were determined by fermentation experiments with the fibrinolysis enzyme activity as the index. Compared the physical and chemical indicators, the exture and the taste of black beans light-flavor Douchi that are fermented under the optimum process conditions after sprouting 48 h with traditional natural fermentative light-flavor Douchi. The study researched the effect of different drying methods on the moisture content and the fibrinolytic enzyme activity of Light-flavor Douchi Powder. At the end of the research, the optimum preparation of Light-flavor Douchi Powder was determined.Results were as follows:(1) Comprehensively finding, black beans compared with soybeans, red beans, mung beans and white kidney bean was more suitable for light-flavor Douchi by selecting the raw material beans with outer wall material and fibrinolysis enzyme activity of light-flavor Douchi as the index. And after 48 hours of germination treatment, fibrinolysis enzyme activity of light-flavor Douchi increased significantly.On the basis of single factor experiment, the selected three factors which influenced fibrinolysis enzyme activity of light-flavor Douchi were in order for the fermentation temperature>fermentation time>quantity of fermentation through orthogonal test to optimize the fermentation conditions of light-flavor Douchi with fibrinolysis enzyme activity of light-flavor Douchi as the index. The optimal fermentation conditions were as follows: 15% inoculation amount, 32? fermentation temperature and fermentation time for 7 days. In the three factors, the fermentation temperature most significantly influenced on fibrinolysis enzyme activity of light-flavor Douchi(p<0.01), the fermentation time significantly impacted on fibrinolysis enzyme activity of light-flavor Douchi(p<0.05),inoculation volume was not found to be significantly affected(p>0.05).(2) The study compared the black beans light-flavor Douchi that are fermented underthe optimum process conditions after sprouting 48 h with traditional natural fermentative light-flavor Douchi,the result shows that protein, amino nitrogen and reducing sugar content of the light-flavor Douchi that are fermented under the optimum process conditions are significantly higher(p<0.05) than the traditional natural fermentative light-flavor Douchi. Amino acid nitrogen content exist extremely significant differences(p<0.01). Fat,total sugar and crude fiber content of the light-flavor Douchi that are fermented under the optimum process conditions are significantly higher(p<0.05) than the traditional natural fermentative light-flavor Douchi.(3) Texture analysis of the light-flavor Douchi that are fermented under the optimum process conditions and the traditional natural fermentative light-flavor Douchi shows that the hardness, springiness, chewiness of the former are significantly lower than the latter.The sensory evaluation of these two kinds of light-flavor Douchi show that the color, aroma and taste of the light-flavor Douchi that are fermented under the optimum process conditions are better than the traditional natural fermentative light-flavor Douchi. The result shows that the fermentation degree and the fermentation quality of the light-flavor Douchi that are fermented under the optimum process conditions are higher than the traditional natural fermentative light-flavor Douchi.(4) In the predrying and after-drying process of light-flavor Douchi, considering all these factors the loss of enzyme activity, drying efficiency and cost, selected 40? low temperature heat pump drying to dry, which the time of predrying was set to 8 h, and the time of after-drying was set to 120 min, the moisture content of the final output was 7.3%,the fibrinolytic enzyme activity was 16350 U/g.