Effect of Chicory Water Extract and Lactulose Syrup on Growth and Viability of Lactobacillus plantarum , Lactobacillus casei and Lactobacillus rhamnosuss in Skim Milk

摘要

The present research aimed to study the effect of chicory extract and lactulose syrup on the growth and viability of three probiotic organisms ( Lactobacillus plantarum , Lactobacillus casei and Lactobacillus rhamnosuss ) and regular yoghurt cultures ( Streptococcus subsp. thermophilus , Lactobacillus delbrueckii subsp. bulgaricus) in skim milk. Three concentrations of probiotic inoculums and prebiotic ingredients (0.5, 1 and 1.5% for probiotic and 1, 3 and 5% for prebiotic) were used to select the suitable ratio in the application experiments. The tested cultures with or without prebiotic were incubated on 42 and 37 ?°C. The obtained results showed that the growth of Lactobacillus plantarum , Lactobacillus casei , Lactobacillus rhamnosuss and yoghurt cultures ( Streptococcus thermophilus , Lactobacillus bulgaricus ) were affected by the incubation temperature in all of the tested bacteria and inoculation percentage in all of probiotic strains individually or mixed with traditional yoghurt cultures. The percentage of viability in traditional yoghurt cultures were increased when cultures were incubated at 42?°C compared with the cultures incubated at 37?°C and different from the viability of Lactobacillus plantarum , Lactobacillus casei and Lactobacillus rhamnosuss which, were increased with incubation at 37?°C compared with incubation at 42?°C. Also, data found that the generation time of all probiotic cultures was decreased in the presence of chicory extract and lactulose syrup due to the enhancement of growth in probiotic cultures. The obtained results can help our further studies for selection the optimum inoculation percentage and incubation temperatures of tested strains individually and/or mixed with traditional yoghurt cultures in the application experiments.