Metabolic responses of kombucha consortium fermentation upon ultrasound-processing

This study investigated the effect of ultrasound-assisted fermentation on the metabolic responses of traditional and mango-flavored Kombucha fermentation. The results revealed significant differences in the sugar consumption kinetics of sonicated kombucha. Sucrose consumption over 9 days of fermentation (F1) was higher for control than US-processed kombucha. During the second fermentation (F2), ultrasound processing increased the rates of sucrose consumption as the US processing time increased. US15 increases sucrose consumption by 19%. Ultrasound favored a higher yield of gluconic, propionic, and isobutyric acids than non-processed kombucha (control), and important changes in the kombucha bioactive compounds profile. Gluconic acid continuously increased to a maximum of 6.74 g/L on D12 (F2) in US15 kombucha compared to 4.17 g/L in non-processed one. The ethanol content was below 0.5 g/L for the sonicated kombucha, reaching its maximum of 0.46 g/L for US7 and 0.25 g/L for US15 kombucha after 28 days of refrigerated storage. Ultrasound-assisted fermentation may cause attenuation of kombucha microbiota and changes in the cellulose fiber, promoting modulation of kombucha consortium metabolism. This study's findings help to develop kombuchas with higher bioactive potential and contribute to optimizing the kombucha fermentation process.