Investıgatıon of Quality Parameters of Some Herbal Teas Fermented with Kombucha

Kombucha is a functional beverage produced by fermenting tea through symbiotic yeasts and acetic acid bacteria in the presence of carbon sources. This study evaluated kombucha produced from rose mallow, sage, chamomile, linden, and rosehip teas for pH, total acidity, color, density, alcohol, °Brix, antioxidant activity, total phenolic content, and antimicrobial properties. During fermentation, pH decreased in all samples. Pre-fermentation phenolic contents were 224.4 mg GAE/mL (linden), 69.8 mg GAE/mL (rosehip), 191.4 mg GAE/mL (rose mallow), 237.45 mg GAE/mL (sage), and 75.6 mg GAE/mL (chamomile). Post-fermentation values were 212.05, 23.3, 215.9, 339.65, and 141.35 mg GAE/mL, respectively. Decreases occurred in linden and rosehip, while increases were observed in rose mallow, sage, and chamomile. DPPH analysis showed increased inhibition only in linden kombucha (25 to 31.7%). Disk diffusion tests indicated no effect against Staphylococcus aureus or Escherichia coli. These findings highlight the influence of herbal tea type on bioactivity during fermentation