Production of yogurt with postbiotic and paraprobiotics of potential probiotic lactic acid bacteria isolated from bee pollen and bee bread

This study was conducted to reveal the probiotic potential of lactic acid bacteria (LAB) isolated from bee bread and bee pollen samples collected from different geographical regions of Türkiye, and to evaluate the functional properties of postbiotics and paraprobiotics obtained from these strains for potential applications in food systems. Following morphological and physiological characterizations (Gram positivity, catalase negativity, fermentation type, salt and temperature tolerance), the LAB isolates were identified by 16S rDNA gene sequencing and their genetic diversity was determined using (GTG)₅-PCR fingerprinting. Among 200 isolates, 24 LAB strains belonging to eight different species were selected: Apilactobacillus kunkeei, Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Lactococcus lactis, Weissella cibaria, Weissella confusa, Leuconostoc mesenteroides, and Enterococcus faecium. The postbiotics and paraprobiotics derived from these strains were evaluated in terms of antimicrobial, antioxidant, biofilm inhibition and eradication capacities, as well as their total phenolic content and organic acid profiles. It was found that postbiotics exhibited higher functional activity and compound content than paraprobiotics. In particular, postbiotics derived from Lpb. plantarum, W. confusa, and A. kunkeei showed strong antimicrobial and anti-biofilm effects against major foodborne pathogens such as B. cereus, E. coli, L. monocytogenes, and S. aureus. These postbiotics also demonstrated antioxidant activities reaching up to 70%, and phenolic contents as high as 800 mg GAE/L. Six strains with the best biofunctional properties (A. kunkeei B2, Lpb. plantarum E5, Lim. fermentum E3, L. lactis M3, W. cibaria V8, and W. confusa S6) were used to produce functional yogurts by incorporating their postbiotic and paraprobiotic forms at a concentration of 2%. The yogurts were analyzed in terms of pH, titratable acidity, solid matter, protein and fat content, water holding capasity, starter culture viability, organic acid profile, color, and rheological properties compared to a control group. The results showed that the addition of biotics accelerated fermentation, maintained acid balance, and enhanced microbiological stability during storage. Especially, W. confusa S6 and Lpb. plantarum E5 biotics significantly improved the rheological properties of yogurt, including viscosity, consistency coefficient, and gel structure.