Estimation of the mechanism for the decrease of cyanides in flaxseed cake fermented with koji Aspergillus oryzae.

Abstract

The distinct health benefits of omega-3 polyunsaturated fatty acids have led to increased production of flaxseed oil as well as the production of its byproduct, flaxseed cake. However, the high level of cyanides has hindered its efficient utilization. Since previous studies showed that filamentous fungi produce cyanide-degrading enzymes of plant seeds, in order to decrease the level of cyanides in flaxseed cake, flaxseed cake was fermented with koji Aspergillus oryzae. The level of cyanides in flaxseed cake fermented with koji A. oryzae was lower than that of unfermented flaxseed cake. To elucidate the mechanism for the decrease, a crude enzyme was obtained from the koji-fermented flaxseed cake and incubated with linamarin, one of cyanides contained in flaxseeds. Linamarin was decreased upon incubation with the crude enzyme. These results indicate that some enzyme produced by koji A. oryzae degraded cyanides in flaxseed cake.