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Wellness

Miso: A Ubiquitous Fermented Food in Japan

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:

  1. Miso: Rice, barley, or soybean grain malt for the koji (Aspergillus oryzae) and brine (sea salt and water) and soybeans.
  2. Shoyu (soy sauce): Wheat and Aspergillus oryzae, brine, and soybeans.
  3. 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!

Categories
Wellness

Amazake: Japan’s 1000-year-old wonder drink

An amazake boom has been underway in Japan, with its market size growing from ¥11.9 billion in 2009 to ¥16.7 billion in 2015 and ¥24.6 billion in 2017 (latest data). (1)

Japanese people drink amazake as a nutritional supplement to prevent heat fatigue in the summer, or as a pick-me-up with breakfast or late in the afternoon.

Amazake (also known as koji amazake) is a non-alcoholic, viscous, white-colored, sweet, traditional Japanese drink, a fermented food made from Aspergillus oryzae and related koji molds. The sweetness of koji amazake is from glucose, derived from starch broken down by the Aspergillus oryzae amylase. Fermenting food results in an improved nutrient composition. Purportedly, koji amazake contains over 300 ingredients in total.

Functionality, amazake is known to include an anti-fatigue effect, bowel movement improvement, a skin barrier function, e.g., improving dry skin, and other effects on human health. These functions result from ingesting approximately 100 mL per day, but human clinical trials have clarified that this amount has no effect on blood glucose levels and weight gain. (2)

Amazake: Functionality, Safety

  References (below)
1Anti-Fatigue Effect3 and 4
2Bowel Movement Improvement5 and 6
3Skin Barrier Function 7
4Safety8 and 9

Source: Ingredients, Functionality, and Safety of the Japanese Traditional Sweet Drink Amazake, (2) Conceptasia, November 2021

Koji amazake has been consumed for a long time, as it appeared in the Chronicles of Japan (Nihon shoki) compiled in 720. The rice-koji is mixed with water and placed in a tank set at 50–60 °C, where the amylase secreted by A. oryzae breaks down rice starch into glucose.

It is a unique beverage for which the main component is glucose, as compared to other sweet beverages such as fruit juice, for which the main sugars are sucrose and fructose. (2)

References

  1. Fuji Keizai Co. Ltd. Foodstuff Marketing Handbook 2021; 2020; Volume 4, pp. 342–345
  2. Ingredients, Functionality, and Safety of the Japanese Traditional Sweet Drink Amazake, by Atsushi Kurahashi, June 2021
  3. Effect of a late evening snack of Amazake in patients with liver cirrhosis: A pilot study, by Nagao, Y.; Sata, M., 2013
  4. Effects of amazake using rice koji intake in sports athletes on physical fatigue and subjective symptoms during exercise training, by Kashimura, O.; Uehara, Y.; Shimazaki, A., 2019
  5. Effect of Amazake ingestion on constipation, by Sumiyoshi, K.; Nakao, M., 2017
  6. Effects of Koji amazake and its lactic acid fermentation product by Lactobacillus sakei UONUMA on defecation status in healthy volunteers with relatively low stool frequency, by Sakurai, M.; Kubota, M.; Iguchi, A.; Shigematsu, T.; Yamaguchi, T.; Nakagawa, S.; Kurahashi, A.; Oguro, Y.; Nishiwaki, T.; Aihara, K.; et al., 2019
  7. Effect of intake of Amazake on skin barrier functions in healthy adult women subjects—A randomized, double-blind, placebo-controlled study, by Ueda, M.; Kitagawa, M.; Koike, S.; Yamamoto, T.; Kondo, S., 2017
  8. Effects and safety of koji amazake: An excessive intake test, by Kurahashi, A.; Yonei, Y., 2019
  9. Safety evaluation of a long-term intake of koji amazake, by Kurahashi, A.; Nakamura, A.; Oguro, Y.; Yonei, Y., 2020