Effect of Bulking Agents, Type of Cultures and Compression Pressures on Functional Properties of Probiotic and Starter Culture Tablets

In the current study freeze dried cultures of Streptococcus thermophilus MTCC 5460, Lactobacillus helveticus MTCC 5463, Lactobacillus rhamnosus MTCC 5462 and Lactobacillus delbrueckii subsp. bulgaricus NCIM 2358 were used for preparation of tablets to be used as either inocula for product preparation or as dietary supplement. Maltodextrin and spray dried lactose as bulking agents were compared for preparation of active ingredients. Selection of bulking agent was based on the viability, activity, micromeritic properties and stability of the active ingredients prepared. Active ingredients of the cultures were mixed with other excipients and subjected to direct compression at different compression pressures viz., low (1–2 kg/cm²), medium (3–4 kg/cm²) and high (5–6 kg/cm²) to prepare tablets. The tablets were analyzed for hardness, disintegration and viability. Viability and activity of the freeze dried cultures were not significantly affected by the bulking agents indicating a good compatibility of cultures and bulking agents used. Between the two active ingredients containing maltodextrin or spray dried lactose as bulking agent, spray dried lactose showed better flow properties, hence it was selected. A significant (P<0.05) increase in the hardness and disintegration time of tablets as well as a significant (P<0.05) decrease in the viability of all four cultures were seen when the compression pressure was increased from 1–2 kg/cm² to 5–6 kg/cm². Hence a compression pressure of 1–2 kg/cm² was selected for preparation of culture tablets.