Abstract: The main purpose of this technique is to newly provide a technique whereby it becomes possible to shorten the time for anaerobic fermentation by reducing the concentration of oxygen contained in a raw material by a method other than an inert gas replacement method that requires the introduction of a facility. This technique provides a method for producing a fermented food or beverage, including a saccharide oxidase action step for allowing a saccharide oxidase to act on a portion or the whole of a saccharide in a raw material, and an anaerobic fermentation step for performing anaerobic fermentation. This technique also provides an oxygen concentration reducing agent for anaerobic fermentation use which contains a saccharide oxidase. This technique further provides an anaerobic fermentation method which includes a saccharide oxidase action step for allowing a saccharide oxidase to act on a portion or the whole of a saccharide in a raw material.

Abstract: Disclosed herein is a novel enzymatic agent effective in reducing acetaldehyde in the oral cavity. It has been found that an aldehyde dehydrogenase derived from a microorganism belonging to the genus Saccharomyces and a threonine aldolase derived from Escherichia coli are effective in reducing low concentrations of acetaldehyde. Therefore, an agent for reducing acetaldehyde in the oral cavity is provided, which contains these enzymes as active ingredients.