Potential probiotic properties of lactobacilli isolated from goat's milk

Abstract

The three strains of lactobacilli isolated from goat's milk - Lactobacillus (Lbc.) casei 21L10, Lbc. johnsonii KB2-1 and Lbc. plantarum 25/1L were selected in previous studies because they showed good processing and protective properties in production of cheeses or lactic acid beverages from heat-treated milk or in model conditions. The aim of this study was to evaluate their potential probiotic properties: resistance to lysozyme, survival in gastrointestinal tract, and hydrophobicity. Testing was carried out in vitro methods: comparison of growth and metabolic characteristics of the strains when cultivated in Man, Rogosa and Sharpe medium with and without the addition of lysozyme (400 μg.mL -1); viability of strains after incubation in simulated environment of gastric juice (pH = 2.0, pepsin) and subsequently in simulated small intestinal juice (pH = 8.0, pancreatin, bile salts) and an ability to adhere to the non-polar solvent in the two-phase system: xylene-water. Lbc. casei 21L10 and Lbc. johnsonii KB2-1 were resistant to the effect of lysozyme, the strain Lbc. plantarum 25/1L was moderately susceptible. To the action of simulated gastric juice was resistant only the Lbc. johnsonii KB2-1, that was subsequently inhibited in simulated small intestinal juice. When using xylene as a model agent, all strains were not hydrophobic. From all the tested strains, Lbc. johnsonii KB2-1 showed good potential probiotic properties, particularly in relation to resistance to lysozyme and the simulated environment of gastric juice.