Formulation of medicinal plant influence on bioactive and health benefits of kombucha tea -

Formulation of medicinal plant influence on bioactive and health benefits of kombucha tea

Kombucha samples containing cinnamon exhibited higher antioxidant and antimicrobial activities, more organic acids, and better sensorial scores. Increasing the cinnamon concentration, certain increases were observed in the amounts of organic acids and in the magnitudes of antioxidants and antimicrobial activities.

Preparation of kombucha tea

The sucrose solution at 6.5% (w/v) was autoclaved for 15 min at 121°C. According to preliminary experiments, appropriate kombucha tea formulations were established (0.7% green tea, 6.5% sucrose solution, and the starter culture). Initially, the sucrose solution (6.5%) and the green tea and medicinal plant were allowed to be brewed for 15 min and then were filtered through a sieve. The tea then cooled down to reach 25°C, and the kombucha tea broth was inoculated by 4% of freshly grown tea fungus. The mixture was covered with tissue paper towels. Fermentation was carried out in an incubator at 28°C. Three medicinal plants, namely, cinnamon (CIN), cardamom (CAR), and Shirazi thyme (SHT) were applied to the kombucha medium to evaluate the effects of medicinal plants on the physicochemical, antioxidant, and sensorial properties of final kombucha samples, and then the kombucha was mixed with green tea at a ratio of 50:50 (0.35%, w/w: 0.35%, w/w) (which yields the flavored kombucha).

Four different ratios of cinnamon: green tea was prepared (100:0, 75:25, 50:50, and 25:75). The effect of cinnamon concentration on physicochemical, antioxidant, and antimicrobial activities of kombucha samples was analyzed for 16 days by intervals of 4 days. Oragnic acids were determined by HPLC.  The broth microdilution method was applied to determine the MIC (minimum concentration of an antimicrobial agent). Sensorial evaluation parameters included flavor, odor, color, sourness, and overall acceptability.

This study serves as a contribution to the hypothesis that medicinal plants can further promote the kombucha in being identified as a functional beverage product. This study revealed that, among the three medicinal plants used herein, the fermented CIN exhibited the highest antioxidant, antimicrobial, and sensorial properties at the end of the fermentation process. Increasing the cinnamon concentration leads to significant increases in the amounts of organic acids and antioxidants, besides higher antimicrobial activities in the flavored kombucha. These findings can be deemed very promising when considering the development of such newly advanced products, not only because of their high level of agreeableness in terms of flavor and odor, but also because of their improved bioactivity and health benefits compared to traditional kombucha tea.

Reference:

Shahbazi, H., Hashemi Gahruie, H., Golmakani, M.T., Eskandari, M.H. and Movahedi, M., 2018. Effect of medicinal plant type and concentration on physicochemical, antioxidant, antimicrobial, and sensorial properties of kombucha. Food Science & Nutrition, 6(8), pp.2568-2577.