Discover how Koji (Aspergillus Oryzae) helps to unlock existing Flavours and textures in your Cooking. Growing Koji mold on foods creates enzymes that convert starches into sugars and proteins into amino acids. This process is called "kojification" and develops a more balanced Umami within the food and dramatically improves its texture.
Aspergillus oryzae, also known as kōji mold (Japanese: ニホンコウジカビ (日本麹黴), Hepburn: nihon kōji kabi), is a filamentous fungus (a mold) used in Japan to saccharify rice, sweet potato, and barley in the making of alcoholic beverages such as sake and shōchū, and also to ferment soybeans for making soy sauce and miso. However, in the production of fermented foods of soybeans such as soy sauce and miso, Aspergillus sojae is mainly used instead of A. oryzae. A. oryzae is also used for the production of rice vinegars. Barley kōji (麦麹) or rice koji (米麹) are made by fermenting the grains with A. oryzae hyphae.
Eiji Ichishima of Tohoku University called the kōji fungus a "national fungus" (kokkin) in the journal of the Brewing Society of Japan, because of its importance not only for making the kōji for sake brewing, but also for making the kōji for miso, soy sauce, and a range of other traditional Japanese foods. His proposal was approved at the society's annual meeting in 2006.
The Japanese word kōji (麹) is used in several meanings, and in some cases it specifically refers to A. oryzae, while in other cases it refers to all molds used in fermented foods, including Monascus purpureus and other molds, so care should be taken to avoid confusion.