Elimination of hexanal by a cell-free extract of baker's yeast.

The decomposition of hexanal, which causes off-flavors in food materials, by Baker's yeast was examined. It was found that Baker's yeast decreased the off-flavor through series of oxidation and reduction of hexanal. First, hexanal was either reduced to hexanol or oxidized to hexanoic acid which has a high threshold level under anaerobic condition. Secondly, hexanol produced in the first step was also oxidized to hexanoic acid under aerobic condition. It was also found that alcohol dehydrogenase, aldehyde deyhdrogenase, and the NADH oxidase system, including NADH dehydrogenase, played important roles in the oxidation and reduction of hexanal.