Strain-dependent effects of the probiotic Lactobacillus crispatus on the physicochemical, technological, nutritional, and antimicrobial characteristics of fermented milk formulated for women

In this study, a fermented milk enriched with Lactobacillus crispatus strains (BC1, BC4, and BC5) was developed with the aim of supporting female well-being, while ensuring technological robustness. Each strain was combined with an exopolysaccharide-producing Streptococcus thermophilus starter culture and its impact on physicochemical, technological, nutritional, and antimicrobial properties of the final product was assessed during 28 days of refrigerated storage (4°C). All formulations exhibited optimal pH values (4.0–4.4), consistent with commercial yogurts, and the incorporation of L. crispatus strains influenced syneresis behavior during storage, likely as a consequence of the acidification observed in probiotic-containing samples. Rheological analysis confirmed pseudoplastic behavior in all samples, with BC4 and BC5 showing the highest consistency and more pronounced pseudoplastic behavior. The addition of the probiotic strains markedly increased total free amino acids, particularly lysine, leucine, glutamic acid, and proline, suggesting enhanced proteolytic activity and potential nutritional relevance for women’s health. Volatile compound analysis revealed a shift toward higher levels of short-chain fatty acids, especially acetic and butanoic acids, which may contribute to both flavor and antimicrobial activity. All probiotic-enriched samples inhibited Escherichia coli H10407 and Salmonella enterica , with BC1 and BC5 showing the strongest antagonistic effects. Among tested strains, BC1 displayed the best survival (≥ 7 log CFU/g after 28 days), indicating suitability for industrial application, while BC5 was the most effective in improving technological and rheological properties. Overall, this study demonstrates the feasibility of producing fermented milk with promising technological and sensory characteristics, supporting its future scale-up and further validation of its health-related potential.