Solid State Fermentation Of Yeast On Corn Flour Quality Improved

Corn is one of the main food crops in the world and has great health function. In the corn flour, structure of nutrients is not balanced and utilization of nutrients is low. At the same time, it has coarse taste、poor viscoelasticity and bed flexibility. These unfavorable factors make corn flour processing and application is restricted. Solid-state fermentation modified corn flour, can improve the processing performance and edible quality of corn meal, improving the added value of corn meal.The work of this study is to through ultraviolet mutagenesis and casein plate filter experiment selected yeast strains which capable of producing protease. Then using the method of gel selected yeast strains which capable of producing glutamine transaminase. In the end, obtained yeast strains which making use of corn protein by corn gluten meal gradient domestication experiment. It haves identified the optimal growth conditions of new strains in corn gluten meal. The experiment can prepare the way for further fermentation experiment.Experiments explored the effects of pretreatment for corn flour and through single factor experiment to explore the optimum pretreatment conditions for corn flour. It is the powder grinding to 80 mesh and the grinding powder under 121 after ℃sterilization 20 min. The corn flour which structure was preliminary changed after grinding and high temperature sterilization is conducive to fermentation experimentsThe work of this study is to through solid-state fermentation of corn flour by the yeast after domestication. Through the single factor experiment and response surface experiments to explore the optimum fermentation conditions: Domesticated strains undet30 ℃, 120 r/min culture 24 h in YPD medium as seeds, seeds vaccination quantity is 10%, solid-liquid ratio is1:1, natural pH, under 30 ℃ferment 48 h. In fermented product, the content of total starch dropped by 16.72%, the content of amylase increase 6.57% and the content of soluble sugar increase 32.51%. In fermented product, the content of small molecular peptide is 1.51 g/100 g, tensile distance is 6.97 mm and setting to sinking is 0.669. So solid state fermentation not only improved the nutrition structure and processing properties of corn flour, while retaining the corn meal the original sensory propertiesThe experiment compared the vacuum drying, vacuum freeze drying and drying effect on corn flour quality after fermentation. After the vacuum drying or drying corn flour color is deeper. The longer drying time and higher drying temperature, the color is deeper. Dried corn flour harden into pieces and been not easy to grind. Vacuum drying and vacuum freeze drying can better retain nutrition and sensory properties of fermented product. Minimal effects of vacuum freeze drying of corn flour quality, but the drying time is longer than the other.By fermented corn flour to mice fed and detection the physiological indexes of mice. Experiments show that compared with the control group of mice blood sugar content and the content of hepatic glycogen of no obvious rise, blood fat dropped by 8.93%. This suggests that corn flour after fermentation can effectively prevent blood sugar and blood fat rise caused by excess nutrients.The viscera index of spleen and liver in mice rose 28.57% and 28.57% respectively. The Super oxide dismutase(SOD) activity in liver tissue rose 9.58% respectively. MDA content in liver tissue dropped 41.60%. These data suggest that fermented corn flour can improve the immune function in mice.It provides an experimental basis through this experiment for solid state fermentation of corn flour by yeast, improve the processing performance and edible quality, improve the added value of corn processing, to promote the progress of the corn processing provides through this experiment.