13-Glucosidase activity of Cyberlindnera (Williopsis) saturnus var. mrakii NCYC 2251 and its fermentation effect on green tea aroma compounds

Yeast fermentation represents a novel strategy to modulate tea aroma compound formation due to its various metabolic activities. A selected non-Saccharomyces yeast Cyberlindnera (formerly Williopsis) saturnus var. mrakii NCYC 2251 was used to ferment green tea slurry. Meanwhile, 13-glucosidase activity of C. mrakii NCYC 2251 was determined. The 13-glucosidase activity assay of C. mrakii NCYC 2251 revealed a positive correlation between yeast biomass (cell count) and 13-glucosidase activity. GC-MS analysis of yeast-fermented and 13-glucosidasetreated tea slurries showed that some glycosylated aroma compounds such as methyl salicylate, benzyl alcohol and 2-phenylethanol increased with the passage of fermentation time. Whereas, the increases of these compounds in 13-glucosidase-treated tea slurries exhibited dose-dependent trends. These results demonstrated the effects of yeast 13-glucosidase on tea aroma compound formation during fermentation.

Automated summary

The use of yeast fermentation and 13-glucosidase treatment can enhance the levels of certain aroma compounds in tea, showing a positive correlation. During fermentation, there is a strong positive correlation between yeast biomass (cell count) and yeast 13-glucosidase activity.