The potential antioxidant capacity and angiotensin I-converting enzyme inhibitory activity of Monascus-fermented soybean extracts: evaluation of Monascus-fermented soybean extracts as multifunctional food additives.

The potential antioxidant capacity and angiotensin I-converting enzyme (ACE) inhibitory activity of Monascus-fermented soybean extracts (MFSE) were investigated. The average antioxidant capacities of 70% ethanol extracts from soybean after fermenting for 15 d at 30 degrees C were increased by a 5.2 to 7.4-fold (0.26 mM trolox equivalent/g dry weight, 91.7% 1,1-diphenyl-2-picrylhydrazyl [DPPH] radical scavenging effect at 3 mg/mL) when compared with those of the unfermented soybean extracts (P < 0.01). The potentially significant antioxidant properties of MFSE are associated with its content of bioactive mevinolins (r= 0.85) and isoflavone aglycones (r= 0.98), which were derived from the soybean during Monascus-fermentation. It was also found that the water extract having a molecular mass 1 to 3 kDa showed the highest ACE inhibitory activity (65.3%), which was remarkably greater (6.5 times) than the control.