Development And Quality Evaluation Of Lactobacillus

This study aims to prepare compound lactobacillus microcapsules, which can protect the orally-administered lactobacillus against the detriment of gastric acid and bile salt, thus reaching intestinal tract and exerting probiotic effects. The low methoxyl pectin(LMP) was used as wall material, Lactobacillus delbrueckii and Lactobacillus fermentum in combination were encapsulated into the microcapsules by ionic-crosslinking process. These microcapsules were characterized structurally. The encapsulating rate, in vitro release, and storage stability of the microcapsules were also evaluated.The preparation process of the compound lactobacillus microcapsules were explored using encapsulation number, release profile as criteria. The effects of LMP and CaCl2 concentrations, solidifying time on the results were considered. The optimal parameters determined by mono-factor and orthogonal experiments were: 2% LMP(m/v), 300mmol/L CaCl2, with 4h solidification. Under these conditions, the composite microcapsules has the average particle size at 2.00±0.02mm; the water content was 4.33±0.29(g/100g); the embedding rate was 99.99%; and the freeze-dried bacteria content was 10.22±0.11 lg cfu/g. The in vitro tests in simulated gastrointestinal fluid showed that the gastric fluid and bile juice had a destructive effect on the unencapsulated bacteria, with 4.25 log units decrease. While the number of compound lactobacillus in microcapsules decreased by 1.03 log units, with high bacteria concentration, indicating the protective effect of microcapsules on compound Lactobacillus. The results of storage stability test shows that under the condition of-20℃, 4℃, 20±2 ℃preservation for 70 d, the bacteria existing in compound lactobacillus microcapsule has 0.80, 0.40, 0.38 lg cfu/g more than naked bacteria, respectively.Structural characterization for the microcapsule wall material showed that LMP molecules combined with calcium ions through chemical bond and formed pectinate calcium molecules.