Potential probiotics and postbiotic characteristics including immunomodulatory effects of lactic acid bacteria isolated from traditional yogurt-like products

Abstract

The current study investigated the probiotic potential and postbiotic characteristics of some lactic acid bacteria (LAB) isolated from traditional high-acid and low-moisture yogurt-like products (Labaneh). The LAB isolates were screened for different probiotic properties, namely tolerance to the gastrointestinal conditions (in vitro digestion, bile salts, and lysozyme), physiological properties (auto-aggregation, co-aggregation, hydrophobicity, adhesion to HT-29 cells, and cholesterol-lowering), production of desirable substances (bile salt hydrolase, antimicrobials, and exopolysaccharides (EPS)), and susceptibility to antibiotics. These LAB isolates had reductions of 4.5 ± 0.1 to 8.5 ± 0.8 Log10 CFU/ml after in vitro digestion. The LAB exhibited cholesterol-lowering (>30%), pathogen-inhibiting properties, and hydrophobicity values of 7.1–86.0%, 18.0–87.3%, and 20.6–87.1% (for xylene, octane, and hexadecane, respectively). Resistance to lysozyme activity was also high in the selected LAB isolates. Selected LAB isolates belong to Streptococcus thermophilus, Lactobacillus delbrueckii, Enterococcus faecium, and Lacticaseibacillus rhamnosus. Two selected LAB isolates (live and killed) exhibited immunomodulatory activities.