Screening of strains producing peptides from tartary buckwheat by solid-state fermentation

Abstract:

[Objective] Strain of tartary buckwheat by solid-state fermentation was screened for high peptides and their fermentation product liquid had antimicrobial and antioxidant activity. [Methods] Aspergillus oryzae, Aspergillus sojae, Actinomucor repens and Rhizopus oligosporus were respectively applied in tartary buckwheat by solid-state fermentation. The protease activity, degree of hydrolysis, soluble peptide yield, inhibition rate, and radical scavenging rate in vitro were regarded as evaluation indexes to verify target strains. [Results] Aspergillus oryzae was the optimal fermentation strain, the highest soluble peptides rate was 38.83%±1.18%, the inhibition rate of E. coli and S. aureus were 96.62%±1.66% and 97.54%±0.54%, the fermentation product liquid prepared the hydroxyl free radical (·OH) scavenging rate and the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) scavenging rate were 55.65%±1.25% and 10.84%±1.03%, respectively. According to the different molecular weight distributions and activity analysis of liquid fermentation product of Aspergillus oryzae of 2 days demonstrated that different components molecular segments had an impact on antimicrobial and antioxidant activity. [Conclusion] Among these strains, Aspergillus oryzae was the most optimal strains which can be applied in tartary buckwheat by solid-state fermentation to produce peptides, and its fermentation product liquid had antimicrobial and antioxidant activity.