Characteristics of Fermented Products Made from Okara Koji

Abstract

We manufactured novel fermented products using okara koji (soy pulp malt fermented using the fungus Aspergillus oryzae) with okara and rice as the fermentation feedstock, and investigated the components and ACE inhibitory activity of the products. When okara koji was employed, a fermented product with high ACE inhibitory activity and abundant in organic acids and amino acids was obtained. Of these amino acids, essential amino acids markedly increased in particular, and the functional ingredient GABA also increased. Moreover, fermented products of okara koji showed high levels of ACE inhibitory activity from the early fermentation stages, which were maintained at a high level until completion of fermentation. In contrast, fermented products of rice koji (rice malt) did not exhibit ACE inhibitory activity during the early fermentation stages, and while the activity increased temporally, the level was lower compared to that of okara koji. Since the fermented products of okara koji maintained their ACE inhibitory activity even after processing by physiological digestive juices, they were considered to be suitable for oral consumption.