Study On The Characteristics Of Immobi-Lized Lactobacillus Plantarum On Bean Dregs And Its Dried Bacteria Powder Preparation

Lactobacillus plantarum can improve the host intestinal micro ecological balance, enhance immunity, lower cholesterol levels, inhibit tumor cell,etc. It is frequently used in food, such as fermented meat products, pickles and fermented drinks. In addition, also in silage, biological anticorrosive and health care are widely used.Immobilized cells technology is positioning free biological cells in restricted areas with physical or chemical methods, and keep the catalytic activity, and make sure that cell can be used more than once. Choosing the right carrier is the key of immobilized cells, bean dregs is food grade and no poison.It is safe and reliable in food products.It has rich of fiber and poor porous.It has a large surface area that attached to bacteria. Mechanical strength and adsorption are also better. The immobilized cells can improve the production efficiency, strengthen the cell tolerability, be use for continuous fermentation and improve the quality of the product.Fermented bean milk not only has the high nutritional value, but can improve the intestinal flora structure,resistant to tumor prevent aging, prolong life efficacy.It also can exclude lead and reduce cholesterol.L.Plantarum in the bean dregs is sheded using ultrasonic shock treatment, the best ultrasound conditions:160W、10min、20℃, when the number of viable cells off carrier up to5.25×109cfu/g. Single factor and orthogonal experiments are done to optimize the immobilizied conditions:the immobilizated time is24h, solid-liquid ratio is1:50, the inoculum is3%. Which conditions is verified, the number of viable cells off carrier up to1.07×1010cfu/g. In order to improve utilization, when reusing the immobilized medium after5cycles, the number of viable cells were up109cfu/g.Free L. Plantarum and immobilizated L. Plantarum is inoculated fermenting soymilk, respectively. Several indexes were measured in the fermentation process,the results as following:soybean milk is fermentated with immobilized L.Plantarum, whose pH lower speed significantly greater than the free one, soybean milk is fermentated for8h,the acidity is65°T exceeding15°T than the free L.Plantarum.Both viscosity difference is not obvious. Living bacterium number in Soybean milk with immobilized L.Plantarum rapidly increased, eventually more than free L.Plantarum; Its free amino nitrogen increased by89.1%,10.24%higher than the free one. With immobilized L.Plantarum fermenting soybean milk, determine the change of soybean isoflavones, Daidzein has been increased from4.287μg/mL to59.94μg/mL, and genistein from0.075μg/mL to10.973μg/mL, both have a large of improvement. Soy saponins of100mL soya-bean milk is80.625mg, drops to48mg after fermentation.The resistance of the immobilized L.Plantarum and free L.Plantarum are analysis respectively, the resistance to pH3.5,2.5,1.5and several different bile salts concentrations are measured, and the results show that immobilized L.Plantarum has more stronger resistance than free L.Plantarum. In addition, both Vacuum freeze-drying and Spray drying are done, with screening protectants and orthogonal, the the results of best protectants:5%Mannitol+0.04mol/L L-Cys+10%Maltose+7%L-Glu (both for quality score), strains survival rate is up to95.84%. The survival rate of immobilized L.Plantarum with the spray drying process is7.92%, the free L.Plantarum survival rate is3.09%, and with the skim milk protection, free L.Plantarum is raise to11.56%.