The investigation of probiotics viability, physicochemical and rheological properties of a probiotic dessert based on sesame paste (Tahini)

This study investigated the possibility of developing a novel functional sesame paste based dessert bearing probiotic bacteria (L.paracasei and B.lactis). Probiotics viability in the dessert as well as pH, acidity, texture and microstructure modifications were investigated during 28 days of cold storage. Cell viability investigation showed that the medium preserved cell viability above 106 CFU/mL during cold storage. The pH and acidity of inoculated desserts have been modified through storage. Flow behavior and texture analysis showed that desserts inoculated with B.lactis showed higher yield stresses and creep elasticity, due to the exertion of polysaccharides by the bacteria. L. paracasei exhibited lower pH values and reduced the creep viscosity and elasticity, due to changes in molecular interactions. Microstructure analysis of the samples showed that the oil was in the form of emulsion and proteins were dispersed in the continuous aqueous phase. According to the results of this study, it is concluded that the exploitation of mixed cultures in the dessert formulation could guarantee acceptable probiotic viability and provide better texture attributes.