Evaluation of the Probiotic Properties of Lacticaseibacillus casei 431® Isolated from Food for Special Medical Purposes

Abstract

Research background. Increasing awareness of the importance of nutrition in health promotion and disease prevention has driven to the development of foods for special medical purposes (FSMPs). In this research, the probiotic strain Lacticaseibacillus paracasei subsp. paracasei (Lacticaseibacillus casei 431®) was incorporated into FSMPs to develop an innovative product. The aim was to investigate the influence of FSMPs matrix on the specific probiotic properties of L. casei 431® in vitro. Experimental approach. A series of in vitro experiments were performed as part of the probiotic approach. After evaluation of antibiotic susceptibility profiles, functional properties such as survival under simulated gastrointestinal tract (GIT) conditions, bile salt deconjugation activities, cholesterol assimilation, antagonistic activity against spoilage bacteria, and adhesion to Caco-2 cell line monolayers and extracellular matrix proteins were investigated. Results and conclusions. L. casei 431® strain, both the lyophilised one and the one isolated from FSMPs matrix, effectively survived the adverse simulated gastrointestinal conditions without significant effect of the food matrix. The effect of FSMPs matrix on the deconjugation activity of bile salts of L. casei 431® was minimal, however, cholesterol assimilation was increased by 16.4 %. L. casei 431® showed antibacterial activity against related lactic acid bacteria whether it was implemented in FSMPs or not. Conversely, the probiotic strain isolated from FSMPs matrix showed significantly higher inhibitory activity against 6 potential pathogens than the lyophilised culture. The autoaggregation ability of L. casei 431® cells was not affected by FSMPs matrix. The adhesion of L. casei 431® bacterial cells to the extracellular matrix proteins was reduced after treatment with proteinase K, with the highest adhesion observed to laminin. Adhesion of L. casei 431® reduced E. coli 3014 binding by 1.81 log units and S. Typhimurium FP1 binding by 1.85 log units to Caco-2 cell lines, suggesting the potential for competitive exclusion of these pathogens. Novelty and scientific contribution. The results support the positive influence of FSMPs matrix on the specific probiotic properties of L. casei 431®, such as antibacterial activity, bile salts deconjugation and cholesterol assimilation, while the incorporation of this probiotic strain brought additional functional value to the FSMPs. The achieved synergistic effect of the join application of L. casei 431® and innovative FSMPs matrix contributed to the development of the novel formulation of an improved functional food product with added value.