Strain-dependent antioxidant properties of lactic acid bacteria isolated from artisanal Tulum cheese

Lactic acid bacteria (LAB) are essential for the quality, safety, and functionality of fermented dairy products. This study evaluated the antioxidant and cellular protective activities of 27 LAB strains isolated from artisanal Turkish Tulum cheese. A multi-assay approach (2,2-diphenyl-1-picrylhydrazyl-DPPH, hydroxyl radical scavenging, reducing power, and β-carotene bleaching inhibition) was used, alongside a Saccharomyces cerevisiae cellular model to determine survival rates under H2O2-induced oxidative stress. Significant strain-dependent variability was observed. DPPH scavenging ranged from 18.05% to 49.65%, while hydroxyl radical scavenging reached 80.05% (S930). Reducing power varied between 56.74 and 1990.03 μM L-cysteine equivalents. In the yeast model, cytoprotection was evidenced by enhanced viability, with survival rates reaching up to 88.04%. While Streptococcus and Lactococcus strains showed strong radical scavenging, Lactiplantibacillus plantarum strains provided superior cellular protection. These findings suggest these isolates may represent potential candidates for developing functional dairy products with enhanced oxidative stability.