The Viability of the Lactobacillus Rhamnosus IL4.2 Strain in Simulated Gastrointestinal Conditions

Abstract

The viability maintenance of Lactobacillus rhamnosus IL4.2 strain in gastrointestinal conditions represents one of the most important characteristics regarding its use for obtaining probiotic products. The tests were performed with a cell suspension kept in 0.5% NaCl. The influence of pepsin (3 g/l) at pH of 1.5, 2, 2.5 and 3, as well as of pancreatin (1 g/l) in the presence of bile salts (1.5, 2, 3 and 5 mg/ml) were determined. The influence of casein and mucin, in a concentration of 1 g/l, was also established in the aforementioned conditions. It was observed that mucin presented a longer viability maintenance, fact also confirmed by the calculation of the mathematical parameters of viability and mortality, when mucin was either used or not, especially in the case of gastric transit. The results proved that the tested strain maintained its viability even at pH between 1.8 - 2 and at an even higher concentration, of 2 mg/ml of bile salts, but up to two hours as of the exposure to the conditions of the simulated small intestinal juice. Such results were also confirmed by the cumulated effect of the simulated gastric and small intestinal juice, the strain thus increasing its viability with an average of 10% in the presence of mucin.

Keywords

• casein
• colonyquant
• mucin
• pancreatin
• pepsin