Validation and determination of Daidzein in Aspergillus oryzae using thin-layer chromatography-densitometry

Abstract

Background: Daidzin (glycosidic isoflavone) bioconversion into daidzein (aglyconic isoflavone) increases its bioactivity. This bioconversion can be carried out using fermentation, using a fungus that has been widely used for making tempeh in Indonesia, Aspergillus oryzae. Objective: This study aimed to validate the method of analysis used and to determine the daidzein content in A. oryzae-fermented edamame using TLC densitometry. Method: Daidzein content determination was carried out on nonfermented (D0) and fermented edamame on days one to four (D1-D4) using the TLC densitometry method. The validation method of analysis was done previously using linearity, the limit of detection (LOD), the limit of quantification (LOQ), selectivity, specificity, precision, and accuracy parameters. Result: The TLC densitometry method used met all the validation method of analysis parameters, except for the selectivity. The daidzein content in edamame from D0 to D4 were 0.0433 ± 0.00221; 0.0336 ± 0.00698; 0.0276 ± 0.00039; 0.0219 ± 0.00041; 0.1002 ± 0.00924 % w/w, respectively. Conclusion: The highest daidzein level was obtained in day four of A. oryzae-fermented edamame.