Scientific research supports the belief that fermented foods improve gut microbiome diversity and health. Fermented foods are common in the Japanese diet. Please see chapter 13 of our book: “Wellness Travel, Wellness-orientated adventureas in Japan: Good daily wellness behaviors whilst exploring Japan’s hinterlands“.
Koji—an amylolytic starter culture specific to Japan
Japan’s warm and humid climate is ideal for the bacteria and mold used for fermentation. For example, koji is an edible mold that lives in grains such as rice plants, barley, and soybeans. It was harvested in the wild, from the heads of rice plants for example, 800 years ago. In the fungi family, a sub microorganism of Aspergillus, Aspergillus oryzae.
Over the subsequent years, koji has been mass produced and refined. The fungal spores can be produced on cooked rice or other grains in a warm, moist environment: rice koji, barley koji, bean koji. There are an estimated 200-plus flavors and fragrances available in Japan based on Aspergillus oryzae.
The three most famous resulting seasoning products are:
- Miso: Rice, barley, or soybean grain malt for the koji (Aspergillus oryzae) and brine (sea salt and water) and soybeans.
- Shoyu (soy sauce): Wheat and Aspergillus oryzae, brine, and soybeans.
- Mirin (a cooking-sake): Rice koji (rice and Aspergillus oryzae), shochu spirits, and mochi rice.
Miso is, most commonly, a fermented rice-malt miso soybean paste used to make the ubiquitous in Japan miso soup. It is high in protein, vitamins, and minerals. Iis believed to have arrived in Japan during the Asuka period (seventh century), with the paste being spread on food. Miso soup is believed to have spread amongst the samurai class during the Kamakura period (late twelfth century to early fourteenth century).
At Ishii Miso, photo above, the miso ferments in wooden barrels for three years for a deeper taste. Mass-produced miso in plastic and metal containers can take as short as three months to manufacture.
Fun to eat, and good for one’s health!