Functional insights into the interaction of Lactobacillus spp. and potentially protective agents

The research addresses the critical need to explore how potentially protective agents (PPAs) influence the cellular characteristics of probiotic bacteria, with a focus on strain-specific responses. This study aimed to reveal the effect of 48-h exposure of the Lactobacillus spp. strains to selected PPAs on the viability, metabolic activity, stress response, surface properties, and physicochemical stability of bacterial suspensions. Results provide new insights into the potential risks or benefits of using the tested PPAs in probiotic production based on the analyzed strains, offering valuable information on their impacts on bacterial cells. Trehalose (TRE) and vitamin C (VC) notably impact the metabolic activity and surface characteristics of cells, with TRE improving viability and VC changing surface roughness and particle size distribution (PSD), suggesting a delicate balance between stress induction and viability enhancement. Inulin (IN) decreased metabolic changes, pointing the complex interplay between PPAs and bacterial metabolism. Results of zeta potential and PSD measurements revealed that other PPAs can either promote uniformity or induce aggregation of the bacterial suspensions. Findings have shown significant strain-specific effects of PPAs on bacterial viability and functionality, suggesting that their careful selection can improve bacterial health. Future directions include exploring the molecular mechanisms behind PPAs' effects and their practical applicability in real food systems.