Effect of prebiotics on lactobacillus acidophilus growth and resulting ph changes in skim milk and a model peptone system

Abstract

The effect of Raftiline® GR, Raftiline® HP-Gel, and Raftilose® P95 prebiotics on growth curves of the probiotic Lactobacillus acidophilus LA-K and resulting pH changes in skim milk and a model system consisting of 0.1% peptone was investigated. Skim milk (100mL) and 0.1% peptone (100mL) each containing either 1% or 3% Raftiline® GR, Raftiline® HP-Gel, or Raftilose® P95 prebiotics were autoclaved, cooled to 37°C, and inoculated with 0.132mL of L. acidophilus LA-K. Both the growth of L. acidophilus and the changes in pH were followed for 16h at 37°C. The growth was determined by measuring the optical density (turbidity) at 600nm. Prebiotics had a greater influence on the growth of L. acidophilus and a greater pH lowering effect in a peptone model system than in skim milk. This observation seems logical since more nutrients are available in skim milk compared to peptone. The system, skim milk or peptone, in which prebiotics are used, does influence the overall desirable effect of the prebiotic. © 2012 Olson DW, et al.