survival kinetics of lactobacillus species during exposure to simulated gastric fluid

Lee, Peh Phong (2010) survival kinetics of lactobacillus species during exposure to simulated gastric fluid. Masters thesis, Universiti Malaysia Sabah.


Download (2MB) | Preview


The overall aim of this research was to develop a standard quantitative method to evaluate the acid tolerance of probiotic cells. The approach was to expose the cells of different concentrations (103- 109 CFU/ml) to a range of pH (i.e. pH 1.5 to 2.5) in order to simulate the varying acidity of stomach. A standard simulated gastric fluid of fixed volume and three model probiotic cells were used in this study. The cell survival kinetics was determined and was described with a mathematical correlation. It was found that the overall death constant (kd ) for three tested strains increased with decrease in the pH and cell concentration. The death constant could be expressed by a general mathematical correlation, kd = k All[pH-9.02 . N0-0.19] where kAll is the acid intolerance indicator and No is the initial cell concentration. The data fitting analysis of this equation give 0.97701 values for coefficient of determination. The k All values of Lactobacillus acidophilus ATCC4356 was found to be lowest followed by Lactobacillus casei Shirota and Lactobacillus casei 01 was the highest. This indicates decreasing in acid intolerance of the cells. In conclusion, a standard and quantitative method has been developed to measure the acid tolerance of probiotic cells and to facilitate selection of strain and process technology.

Item Type: Thesis (Masters)
Uncontrolled Keywords: standard quantitative method, probiotic cell, acidity of stomach, gastric fluid, Lactobacillus casei, acid tolerance
Subjects: T Technology > TP Chemical technology
Divisions: SCHOOL > School of Engineering and Information Technology
Date Deposited: 08 Jul 2013 05:32
Last Modified: 11 Oct 2017 03:02

Actions (login required)

View Item View Item