ACE inhibitory and hydrolytic enzyme activities in textured vegetable protein in relation to the solid state fermentation period using Bacillus subtilis HA

Abstract

Textured vegetable protein (TVP) was fermented by solid-state fermentation using Bacillus subtilis HA and production of biologically active compounds were examined with fermentation time. The TVP fermented resulted in the highest protease activity at 48 hr, where as α-amylase activity was the highest at 24 hr. During the fermentation the peptide and tyrosine content increases drastically and then it decrease gradually after 48 hr. The fast protein transition to low molecular peptides in early fermentation period was confirmed with sodium dedecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC) analysis. Fibrinolytic enzyme activity proportionately increased with the fermentation time and the highest enzyme activity was 25.2 unit/g after fermentation for 120 hr. In the evaluation of ACE inhibitory effect, IC50 value of fermented TVP and its crude peptides was similar with 2.19 and 1.21 mg/mL, respectively. Peptide fraction below 3,000 Da showed 0.5 mg/mL of IC50 value. The peptide fraction (III) with molecular weight of 500–999 Da separated from SEC was consisted of 7 amino acids, indicated 0.094 mg/mL of IC50 value which is 23 times higher than the fermented TVP.