Investigation of the physicochemical, antioxidant, antibacterial and microbiological properties of kombucha tea prepared with lavandula stoechas (Karabaş otu)

With the increase in global population, consumer interest in functional foods and the demand for product diversity are rising. Plants known for therapeutic properties play an important role for this demand. In this context, samples with functional properties were created by adding Lavandula stoechas to kombucha tea. In the study, the physicochemical, bioactive, antioxidant, and microbial properties of traditional black-tea based kombucha and Lavandula stoechas infusion-enriched variants were compared during 14-day storage, and the effect of Lavandula stoechas addition on the nutraceutical potential of kombucha was evaluated. Samples were prepared from black-tea (Sample1), black tea-Lavandula stoechas mixture (Sample3), and Lavandula stoechas (Sample5) infusions. Fermentation, pH, titratable acidity, Brix, CIE Lab* color parameters, total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC), DPPH/ABTS radical scavenging, Iron (Oyaizu, 1988)/Copper (CUPRAC) reducing capacities, and microbial populations (TAMB, yeast, AAB, LAB) were analyzed. Data statistically evaluated by ANOVA. The addition of plant significantly increased TPC and TFC; the pure Lavandula stoechas variant exhibited the highest TPC (1344.71 mg GAE/L) and antioxidant-capacity values (DPPH %inhibition: 89.45; Iron(III) Reducing Power: 2333.75 μM TE/L). While pH decrease, acidity increase were observed during storage, microbial populations increased in the early period and became stable; AAB and LAB showed sensitivity to the substrate. Color and Brix parameters followed more stable course. Integration of plant offers a promising strategy for developing functional beverages by optimizing the phenolic profile. Findings support the use of local plants in nutraceutical applications. Future studies should include compound-specific analysis and in-vivo validations.