The evaluation of chemical, antioxidant, antimicrobial and sensory properties of kombucha tea beverage.

The aim of the present study was to determine the chemical composition (organic acids-acetic, tartaric, citric; sugars-sucrose, glucose, fructose; total acidity, alcohol content, pH-with FTIR instrument; content of selected mineral compounds-AAS instrument), antioxidant activity, antimicrobial activity and sensory profiles of prepared kombucha tea beverage. Black tea with white sugar as a substrate for kombucha beverage was used as a control sample. The dominant organic acid in kombucha tea beverage was acetic acid (1.55 g/L), followed by tartaric and citric acids. The sucrose (17.81 g/L) was the dominant sugar from detected sugars. Antioxidant activity of beverage tested by reducing power method (1318.56 mg TEAC/L) was significantly higher (p < 0.05) in comparison with black tea (345.59 mg TEAC/L). The same tendency was observed for total polyphenol content which was significantly higher (p < 0.05) in kombucha beverage (412.25 mg GAE/L) than in black tea (180.17 mg GAE/L). Among mineral compounds, the amount of manganese (1.57 mg/L) and zinc (0.53 mg/L) was the highest in kombucha tea beverage. Results of antimicrobial activity of kombucha tea beverage showed strong inhibition of Candida krusei CCM 8271 (15.81 mm), C. glabrata CCM 8270 (16 mm), C. albicans CCM 8186 (12 mm), C. tropicalis CCM 8223 (14 mm), Haemophilus influenzae CCM 4454 (10 mm) and Escherichia coli CCM 3954 (4 mm). Sensory properties of prepared beverage were evaluated overall as good with the best score in a taste (pleasant fruity-sour taste). The consumption of kombucha tea beverage as a part of drinking mode of consumers due to health benefits is recommended. © Association of Food Scientists & Technologists (India) 2019.