Efficacy of Inula racemosa Hook F and Saussurea lappa as a Growth Promoter of Yoghurt and Probiotic Culture in Yoghurt

Herbs are antimicrobials, they may affect probiotic viability. The present study was conducted with objectives to find antagonistic effect of herbal extracts, probiotics and normal flora of yoghurt and its effect on its viability, sensory and rheological parameters. The result indicates that selected herbs have low antagonistic effect against beneficial probiotic bacteria, while it is effective in much lesser concentration against pathogen. The presence of Inula racemosa Hook and Saussurea lappa resulted in higher count of yoghurt culture, S.thermophilus and L bulgaricus (9.61 log₁₀ cfu/ml), non significant difference was absorbed within 1% and 1.5% (w/v) concentration of Inula racemosa hook and 9.50 log₁₀ cfu/ml, non significant difference was absorbed within 0.5% and 1% (w/v) concentration of Saussurea lappa, however significant difference was absorbed within the two herbal yoghurt. The former resulted in higher count of Yogurt culture on 0 day of storage compared to plain-yogurt (9.27 log₁₀cfu/ml; p>0.05). Viable Probiotic culture bifidobacteria and L. casei counts reduced from day 7 to day 21 of storage for all yogurts with the fastest rate occurred in plain-yogurt. Viable Probiotic culture counts on day 21 of storage was significant for Inula racemosa Hook (6.79 log₁₀ cfu/ml) and Saussurea lappa yogurt (7.00 log₁₀ cfu/ml) washigher thanplain-yogurt (5.02 log₁₀ cfu/ml) The increase in the viable cell counts for both yogurt bacteria during the first 7 days coincided with the increase in TTA and marked reduction (p<0.05) in pH recorded on day 7 of storage. All mean scores for the different sensory attributes of the two herbal yoghurts were within the commercially acceptable range (4–9 scores) recommended for yoghurt by the Karl Ruther nine points scheme. Herbal yoghurt resulted in significant decrease in firmness of yoghurt however consistency (g s) of herbal yogurt with 1% (w/v) of Inula racemosa Hook and 1.5% (w/v) Saussurea lappa was at par with control. In general Cohesiveness (g), and Index of Viscosity (g s) in herbal yoghurt showed a significant increase (p>0.05) compared tocontrol.