Effects of fermentation time on the bioactive constituents of , a traditional fermented food of Nepal.

is a traditional food prepared by the natural fermentation of cooked soybeans. The fermented is known to have several bioactive constituents, however, only limited reports on the effect of fermentation time on the bioactivity of are available. Therefore, in this work, changes in phenolics content and radical scavenging activity of at different fermentation times were explored. Furthermore, the optimum fermentation time for maximum bioactivities (total phenolic content, total flavonoid content, and DPPH radical scavenging activity) was determined using one-factor response surface methodology. The numerical optimization suggested an optimum fermentation time of 29.6 h with significantly higher total phenolics and flavonoid contents of 62.84 ± 0.89 mg GAEs/g dry extract, 45.41 ± 0.57 mg QEs/g dry extract, respectively ( < 0.05) compared to traditionally fermented . Similarly, the IC concentration for DPPH radical scavenging activity of 1.78 ± 0.01 mg dry extract/mL, was significantly lower than those for traditionally prepared ( < 0.05). Moreover, optimized had significantly higher overall sensory scores compared to the traditional sample. The results suggested that fermentation time affects the amount of bioactive constituents of . Further studies are needed to explore the changes in the type of phenolic and flavonoid compounds.