In this study, the sugar was replaced using different concentration of inulin (1, 2 and 3% w/w) to assess the growth kinetics pattern of Streptococcus thermophilus (ST 144) and Lactobacillus delbrueckii ssp. bulgaricus (LB 144) in the growth medium M-17 and MRS as well as in cow milk medium. The growth rate was found significantly (P < 0.05) higher in 3% inulin supplemented M-17 and MRS 0.21 ± 0.00 and 0.24 ± 0.00 respectively. In cow milk medium growth rate was significantly (P < 0.05) higher and similar for both the culture in 3% inulin supplemented medium. Generation time (in h) for ST 144 and LB 144 was also found significant (P < 0.05) in 3% inulin supplemented medium 1.28 ± 0.01 and 1.43 ± 0.02 respectively. Changes in pH (Δ pH) and acidity (Δ acidity) were also studied for individual culture in cow milk medium. Viability was also highly significant (P < 0.05) at day 7 in 3% inulin supplemented milk medium. This research showed that the addition of inulin as a prebiotic in broth and cow milk medium stimulated the growth and viability of NCDC yoghurt cultures which can be further used to incorporate in fermented milk product yoghurt for increasing its biofunctional properties.

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