The Study On Probiotics Properties Of Lactobacillus. Salivarius FBC05

Lactobacillus salivarius has a lot of physiological functions as main probiotics community in gastroenteric environment of healthy human. The development and application of Lactobacillus salivarius as a kind of probiotics was more researched, with the physiological functions of probiotics understandered. One of the mainly physiological functions was its antimicrobial activity. In this paper, the fermentation conditions of Lactobacillus salivarius FBC05 to produce antimicrobial substances were studied, the antimicrobial components of L. salivarius FBC05 fermenting liquor were analysed. This study provided some evidences for the application of Lactobacillus salivarius in food science.In this paper, Firstly, the culture conditions of L. salivarius FBC05 for growth and antibacterial substance production were investigated in an improved MRS media (sucrose 10g/L, the peptone 5g/L, the beef extract 25g/L, the yeast extract 5g/L, Mg²⁺ 0.1g/L, Na⁺0.5g/L, Mn²⁺0.05g/L, Tween-80 2ml/L). The optimum culture conditions were obtained: the temperature 37, the culture starter is 1%(v/v), the initial pH of cultural media 5.5.The properties study of the antibacterial substance showed that they were heat stability (121℃, 30min), active at low pH and non-sensitive to protease. And its range of antibacterial is wide and they could inhibite G⁺ and G^-, but no effect to epiphyte. The antibacterial substances were extracted by n-propanol and separated by Sephadex G-75. The HPLC analysis results showed that the antibacterial substances were some kinds of organic acid, and these acids had cooperated effect.The reducing cholesterol ability of L. salivarius FBC05. were also researched. The results showed that afterfermentation for 48h, the reducing rate of cholesterol was 32.8%. The reducing rate was influenced by the culture starter. If the culture starter was 6%(v/v), the reducing rate was 37%.The survival properties of L. salivarius FBC05 was studied in imitating gastroenteric environments. The results showed that this strain survived well both in artificial gastric fluids at pH3.0～4.0, and in artificial intestinal fluids. The results indicated that the strains of L. salivarius was steadily in digestive system.To ensure the physiological activity of the strain in preservation and application, the protecters were studied in freeze-drying. The protecters were optimized by orthogonal design. The protecters consisted of trehalose 200g/L, glycerol 20ml/L, degrease milk 100g/L. Using this protecters, the survival rate of the strain was 89%. The technologic process of L. salivarius FBC05 freeze-drying was the suspended culture pre-incubated at 37℃for 3h, and frozen at -76℃for 2h, the survival rate was 90.4%.