Effect of Heat Stress on the Resistance of two Spore Forming Bacillus Species in the Gastrointestinal Tract Simulation Model and their Probiotic Properties

In recent years, the application of spore-forming bacteria in probiotic food supplements and medicine have become more interesting due to their stability in stressful condition of production line and gut environment. In the current study, the resistance of Bacillus coagulans and Bacillus subtilis in response to heat stress and simulated gastrointestinal tract was investigated. Moreover, the aggregation and hydrophobicity of cell surface of these strains were evaluated. The results showed a survival rate of more than 80% for both species after enduring heat stress and undergoing simulated gastrointestinal conditions. In addition, Bacillus coagulans showed a higher autoaggregation and coaggregation ability compared to Bacillus subtilis. In addition, both probiotic species presented a high tendency toward adhering to the hydrocarbon solvents like chloroform and ethyl acetate. This study was a continuation of previous studies conducted with the aim of developing and optimizing functional edible coating for the production of probiotic rock candy (Nabat) using spore-forming probiotic bacillus, to ensure the survival and effectiveness of the strains.