Studies on the Quality Control of Fermented Brown Rice and Rice Bran with Aspergillus oryzae by Metabolome Analysis Using ¹H-NMR

Abstract

Fermented brown rice and rice bran with Aspergillus oryzae (FBRA) is a processed food prepared from brown rice and rice bran. Although FBRA α-amylase activity is monitored as an indicator of fermentation, the evaluation of FBRA quality remains insufficient. We non-targetedly compared metabolite profiles in accepted FBRA, defective FBRA, and unfermented materials using ¹H-NMR coupled with principal component analysis (PCA). Accepted FBRA was clearly separated from defective FBRA and unfermented materials. We also compared twenty-five accepted FBRA samples, where PCA showed that plotting of accepted FBRA results in dispersion that is unbiased toward different production dates and different fermentation apparatuses. These results indicated that accepted FBRA is manufactured with a consistent quality.