Coffee-Flavoured Kombucha: Development, Physicochemical Characterisation, and Sensory Analysis

Considering the health benefits of kombucha, already widely studied, the objective of this study was to develop kombucha beverages with the addition of an infusion of specialty arabica coffee from the first fermentation, varying the proportion of specialty coffee (2% to 13%), and evaluate their pH, volatile acidity, degree of alcohol, centesimal composition, sodium contents, and colour parameters to determine the acceptability of the beverages. Concerning the pH, all of the formulations conformed with the kombucha identity standard, but K3 (11% coffee) and K4 (13% coffee) were below the established minimum for volatile acidity. Except for K4, all of the other formulations were classified as alcoholic kombuchas, although their values were very close to the limit for non-alcoholic beverages. The formulations presented low sugar and sodium contents, which corroborated their low caloric value. Therefore, coffee-flavoured kombucha fermented for 18 days becomes an option for consumers looking for low-calorie, refreshing, and healthy drinks. The luminosity of the beverages decreased as the proportion of coffee increased, and consequently, the values for a* and b* increased, indicating a strong tendency for a yellowish-red colour. Sensorially, the formulations K4 and K3 were the most well accepted in all respects and can therefore be considered formulations with high commercialisation potential.