Biochemical component changes of Curcuma longa - Black tea triggered by kombucha fermentation using metabolomics analysis

This study explores the biochemical indices across three distinct experimental groups: the Curcuma longa L. fermentation Group (CF), the Curcuma longa L. and black tea fermentation Group (CT), and the black tea fermentation Group (KF). After fermentation, the detection of basic indexes revealed that the CT group had the highest total sugar content and gluconic acid levels, at 4.48 mg/mL and 3.20 mg/mL, respectively. Additionally, the KF group exhibited the highest levels of sucrose, polyphenols, and total flavonoids, measuring 28.67 mg/mL, 236.76 μg/mL, and 0.20 mg/mL, respectively. Ethanol content was no more than 0.16% vol in all groups. A qualitative analysis of the aforementioned biochemical parameters revealed the presence of 8 carbohydrates and analogs, 8 sesquiterpenoids, 6 flavonoids, 6 organic acids, 5 alkaloids, and 21 glycosides. We further identified two unique pathways pertinent to fermentation: glucuronic acid interconversion pathway and the cyanogenic amino acid metabolism pathway. Key metabolites influencing kombucha include α-ketoglutaric acid, D-xylitol, ribitol, dhurrin, and lotaustralin. Underscoring the significance of Curcuma longa L. and black tea fermentation. These results elucidate the differential expression of metabolites and their regulatory mechanisms.