Marufuku Koji Starters│From koji　starters koji bean sprouts until the soy sauce, miso, sake and seasonings

With the Koji Starters

Koji is used in the production of brewing foods (soy sauce, miso, sake,etc.). koji starters is the spores of aspergillus oryzae used to produce such koji. There are two types of koji starters: granular and powdery. The former just dries rice on which the spores grow, and the latter gathers the spores only.
In the brewing industry, koji starters is also called as "moyashi". It is said to have come from the word [moyasu (moyashi)] on the basis of the word [moeru] from the image of germination.

With the Koji

Steamed grains (such as rice, soybean, wheat) on which aspergillus oryzae grows proliferously are called koji.
Koji, containing a number of enzymes produced by aspergillus oryzae, is capable of decomposing grains with such enzymes.
The decomposition substance of grains produced by such enzymes, containing a lot of glucose and amino acids, will be the source of nutrition of brewing microorganisms such as flavor ingredients and yeast. Also, because the nature of koji is subject to change depending on koji starters to be used, you should select koji starters suitable for each variety to be produced. (Select strong proteolytic enzymes for soy sauce, while select strong saccharifying enzymes for sake.)

Kind of the Koji Starters

We provide koji starters for soy sauce, miso and sake..
We will introduce you the best koji that meets your needs. Please contact us.

We provide a variety of products: aspergillus with strong protease and glutaminase, aspergillus with strong cellulase and pectin lyase, Marufuku traditional aspergillus, etc.

We provide a variety of products: red miso-based, light-colored miso-based, barley miso, bean miso, Kyushu barley miso, for sweet sake, shio koji (salted rice malt) and selling koji.

We provide products suitable for each sake type: highly-reputed "Ginrei" for particular named sake, "Sakigake" for Tanrei, "Fuji" for Nojun, etc. Since the type is also different, please have a look.

The history of the Koji Starters

Beginning of Koji Starters

Koji has been existed since old times. It is said that koji was produced because wild fungi were seeded in nature at that time. It is presumed that repetition of such seedings selected mold that grows well in steamed rice. The mold is thought to become aspergillus oryzae.
It is said that, from around 10th century, the production method changed from natural seeding to Tomodane (Tomokoji) method where only well-made koji produced by natural seeding is used. Tomodane is a seed that cultured aspergillus oryzae, which is treated in the same way as koji starters.
Tomodane at early times was unstable. In the Muromachi period, it became possible to stabilize the aspergillus oryzae spores by adding wood ash to steamed rice. This is the base of current koji starters.

Reference

【Quoted from Rohen Kanwa Vol. 1 issued by Nihon Jyozo Kogyo (February 15, 1976 issue)】
According to Dr. Kinichiro Sakaguchi (Journal of the Brewing Society of Japan Vol.58 No.5, 1963), origin of koji starters was considered as follows:
“A book called ‘Ryounoshuge’ published at the beginning of the Heian period (9th century) describes Ritsuryo (codes) and institutions at the Nara period or earlier. It says that the proportion of making ‘Mishou’ should be 8 g? (approx. 1.44 liters) of ‘Kikushimai’ to 1 to (approx. 18 liters) of total ingredients. This ‘Kikushimai’ is suspected to be koji starters. In China, the character ‘shi’ means plant seeds. Therefore, I don't think it is completely unreasonable to consider ‘Kikushi’ as koji starters.”
Brewing method of "Hishio (sauce)" is said to have come down in the Emperor Shomu era (8th century), and a "sake brewing method" is said to have come down in 5th century. It is said that documents related to sake brewing which were written when the "sake brewing method" came down to Japan did not mention anything about koji starters. Assuming that there was no koji starters at the time of China, it is reasonable to consider that a new technique that uses koji starters started in either Japan or Baekje (Kudara) during 300 years after the sake brewing method came down to Japan.

Bits of knowledge of the Koji Starters

Koji Starters and Ash

When producing koji starters, we have traditionally sprayed wood ash into ingredients since old times. This method was empirically invented by early people, in which the following effects have been observed:

Since the medium is alkalified, we suppress the growth of bacteria that are weak in alkalinity, and increase the purity of koji starters.
Phosphoric acid and potassium in the wood ash becomes the nutrients of aspergillus oryzae, while copper, zinc, and other minerals that are minor components of the ash have the power to promote adhesion of spores as well as improve the color of spores.
The use of wood ash is said to contribute to the durability of aspergillus oryzae spores.

Growth condition of the Aspergillus oryzae

Appropriate temperature, oxygen, moisture and nutrients are required to their growth. Weak acid pH is preferred.

Temperature: Aspergillus oryzae in the state of hyphae is capable of living at between 8 ℃ and 45 ℃, and successfully grows at around 25 - 37 ℃. The optimum temperature for growth is 32 - 37 ℃. (It may vary by strain.)
To improve the growth of aspergillus oryzae, it is necessary to appropriately adjust the temperature in a culture chamber and keep the optimum temperature for growth so as not to dry aspergillus oryzae.

Oxygen: Oxygen is absolutely necessary, but oxygen demand varies a lot by strain.
The amount of oxygen consumption is said to be related to the viability and enzyme production capacity, etc., which is also concerned with operations in koji production.

Water: Aspergillus oryzae grows well in a liquid medium, but it also grows in a relatively low-moisture medium. It is more resistant to low-moisture environments than bacteria.
Bacteria can barely grow with the amount of steamed rice moisture, but aspergillus oryzae can grow enough with the amount. This helps to suppress the growth of bacteria during koji production and lead the dominance of aspergillus oryzae. However, since drying causes the poor growth of aspergillus oryzae, we must keep humidity in a koji production chamber high.

Nutrition: Nutrients are a very important element for the growth of aspergillus oryzae. Although it can grow proliferously on most grains (only pregelatinized ones), if there is a skin that cannot be decomposed by aspergillus oryzae, nutrition intake is prevented and the growth is suppressed.
In the case of rice, the higher the polishing ratio becomes, the more nutrients are reduced and the growth is delayed.