LAUSR

The present study explored biochemical transformation and optimization of fermentation method for enhanced content of flavonoids in a composite extract of Syzygium cumini seed, Mangifera indica seed, Momordica charantia fruit, and Gymnema sylvestre leaf along with the fermentation kinetics. The herbs were mixed and extracted in hot water. The extract was fermented using Wickerhamomyces anomalus (yeast). Box-Behnken design was applied to determine the best possible combination of variables to obtain the maximum content of flavonoids. The variables were substrate concentration (20%, 40%, and 60%), inoculum volume (2.5%, 5%, and 7.5%), and incubation time (60 h, 72 h, and 84 h). Further, the physical parameters during fermentation were determined to establish the kinetics of the process. The content of Luteolin, Quercetin, Kaempferol, and Isorhamnetin was positively affected by all three variables whereas Apigenin content was negatively affected by incubation time, i.e., the higher the incubation time, the lower the content of Apigenin. Overall content of flavonoids was affected by interactions between variables as indicated by contour plots. Actual content of flavonoids using suggested optimum conditions was in agreement with model predicted values although the effect on Apigenin content was more complex. It was further optimized using the help of the model equation.