What is koji?

If you have had Japanese cuisine before, you may already have had an encounter with koji because it is indispensable to Japanese food culture. Koji is a mold made from steamed grains, such as rice, wheat and soybeans. It has been propagated with a fermentation culture, aspergillus oryzae, and cultured under the appropriate condition. Koji can be used in numerous Japanese typical seasonings such as miso, sake, soy sauce, mirin (sweet Japanese rice wine) and vinegar.

The super mold with a 2,000-year history

Japanese people have used koji in everyday life for over 2,000 years. According to the “Fudoki,” and ancient description of culture and geography in Japan’s various regions, the first record of using koji was found in the Nara period in the early eighth century. It indicates that people used koji to produce sake in those days. During the Edo period (1603-1867), people would drink a traditional beverage called “amazake” to overcome extreme heat. Surprisingly, people are still fascinated by koji no matter where they are from because koji is beneficial in countless ways.

Koji’s health benefits

Like other fermented food such as kimchi, koji has many health benefits. Firstly, it is a great source of probiotic, living bacteria that helps keep us healthy through nutrient absorption, supporting immune function and controlling inflammation. Secondly, it also produces essential vitamins during its metabolism. These vitamins such as B1, B2, B6 and niacin play an essential role in skin metabolism. Finally, an enzyme made from koji has a great impact on metabolic health to help digestion and protect the gut from bad bacteria.

Sustainable uses of koji to change our future

Koji is now utilized for a sustainable society as it is expected to address the food crisis by feeding animals koji feed. Kyushu-based koji company has invented technology to turn food waste into nutrient-rich livestock liquid feed by culturing koji fermentation to food waste. This feed is highly nutritious, enough to raise livestock with less feed in a shorter period compared to previous livestock feed, and to make livestock feces into nutrient-rich manure.

Furthermore, a brewing company Gekkeikan has advanced development technology to produce bioethanol from koji and sake yeast. If this technology is established, koji-made bioethanol can be an alternative to petroleum-based products.

Koji, well-known for its health benefits, is no longer only for human consumption. It now plays a vital role to make our planet healthy and sustainable. Although koji is just a microorganism, its capability and value may be still waiting to be discovered just like in the past.