Preparation And Stability Of Lactobacillus Plantarum Sustained - Release Microcapsules

Probiotics can colonize and grow in the human gut, and improving the human intestinalmicroecological balance, thereby promoting the body keep healthy. However, adverse conditionssuch as low pH gastric acid and bile in digestive tract will seriously affect the probiotic activity,resulting in the number of viable probiotics into the intestinal tract to reduce, impacting of itscolonization and playing probiotic efficacy. Microencapsulation can protect probiotics from badenvironments to avoid damage．Extrusion, a convenient and mild way of microencapsulation, issuitable for the preparation of probiotic microcapsules.In the study, extrusion was used, sodium alginate and chitosan as wall material to preparemicrocapsules, the embedding rate and release properties of the microcapsules were researched.The optimization of microencapsulation conditions was carried out by the method of responsesurface analysis. The microcapsules were dried by vacuum freeze-drying technology, andoptimized composite protectants formulation to increase the survival rate of probiotics in frozenmicrocapsules. And the intestinal tolerance, storage stability and cholesterol-lowering ability ofmicrocapsules were analyzed.1. In the experiment, take chitosan-sodium alginate as wall material to prepareLactobacillus plantarum sustained-release microcapsules, on the basis of single-factorexperiments, the method of Box-Behnken response surface analysis was adopted, theoptimization of microencapsulation conditions was carried out. The results indicated that theoptimal encapsulation conditions were sodium alginate2.7g/100mL, chitosan0.8g/100mL,calcium chloride2.0g/100mL, embedding rate was76.24%. The particle size of microcapsuleswas1.63mm. The microcapsules obtained using this formula displayed good sustained-releaseperformance in mimic intestinal environments, the cumulative release time was8h.2. The optimum formula was determined by orthogonal experiment: glycerol2%,skim milk6%, ascorbic acid0.6%, trehalose9%. Under such condition, the effect was significant toimprove cell survival rate, the results indicated that the survival rate of dried Lactobacillusplantarum reached83.7%.3. After being treated in simulated gastric fluid for3h, the cell survival rate of fresh andfreeze-dried microcapsules remained at a high level, which could reach75%. The number of viable cells were1.75×109and1.52×109cfu/g. After3h in simulated intestinal fluid, the survivalrate of viable cells in microcapsules could reach70%. It showed, the microcapsules have goodtolerance in simulated gastrointestinal fluid.4. Under the condition of-20℃storage for six months, the number of viable cells inmicrocapsules was5.8×108cfu/g. Stored at4℃, the microcapsules also had good stability. While,at25℃the number of viable cells in microcapsules was reducing. Therefore, the microcapsuleswere stored at-20℃. At37℃, the fungus powder in a month when you save only a little ofviable cells could be detected, but the number of viable cells in microcapsules still reached1.9×108cfu/g after storage two months, indicating the wall material of microcapsulation played agood protection effect.5. Degrading rate of cholesterol of Lactobacillus plantarum powder was28.46%.Degrading rate of cholesterol of microcapsules was25.73%. Although Degrading rate ofcholesterol of encapsulated lactobacillus plantarum was lower than non-encapsulatedLactobacillus plantarum, still showed good degradation effect. It was indicated that encapsuleddid not affect degradation of cholesterol ability of Lactobacillus plantarum.