History of Natto and Its Relatives (1405-2012 - SoyInfo Center

germination can be found within a 24 hour period.
Tables show: 8.1 Propagative and physiological
characteristics of Bacillus natto Sawamura. 8.2 Vitamins in
soybeans (per 100 gm). Continued. Address: National Food
Research Inst., Tokyo.
579. Watanabe, Tokuji; Ebine, Hideo; Ohta, Teruo. eds.
1971. Hamanattô [Hamanatto]. In: Tokuji Watanabe, H.
Ebine and T. Ohta, eds. 1971. Daizu Shokuhin [Soyfoods].
Tokyo: Korin Shoin. 271 p. See p. 123, 139-40. [Jap; eng+]
• Summary: An excellent scholarly work. This subchapter
was translated by Alfred Birnbaum. Chapter 8, titled
“Fermented soyfoods,” has four parts, beginning with
“Natto.”
Introduction: There are two types of natto: regular natto
(itohiki natto), produced by the action of natto bacteria on
cooked soybeans, and salty natto (shio-natto), produced
by letting a koji mold [Aspergillus oryzae] grow on the
cooked beans [to make soybean koji], then adding salt
water. Although both are traditional fermented soyfoods
that have been passed down in Japan from ancient times,
the fermenting agent, production method, and nature of
each product are different. The main fermenting agent for
regular natto is bacteria and, as no salt is added to the basic
ingredients as with salty natto, the ripening time is shorter,
although the fi nished product does not keep well. Also
regular natto has the characteristic of forming large amounts
of sticky fi laments. By comparison, salty natto requires
that the koji-molded soybeans ripen in saltwater, the main
fermenting agents being the koji mold in the beginning, and
yeasts and lactic acid bacteria towards the latter end of the
process. As the amount of salt present is high, the ripening
time required is comparatively long, taking ordinarily from
several months to about a year. Salty natto is usually sold as
a blackish, semi-dried product, with absolutely no formation
of sticky fi laments, but rather with a distinctive fl avor
derived from the addition of the salt and other seasonings.
The large amount of salt used also makes it keep well.
At present, the production of regular natto is by far the
larger of the two, being carried out in all regions of Japan;
this product is better known and is usually referred to as
simply “natto.” On the other hand, salty natto is produced
as the specialty product of such specifi c places as Kyoto
(Daitokuji nattô), Nara (Jofukuji-nattô), and Hamamatsu
(Hama-natto) (p. 123).
8.1.9 Hama-nattô: Hama-natto is a variety of salty natto
made in and around Hamamatsu in Shizuoka prefecture. It
is unrelated to regular (itohiki) natto except that both are
fermented soy products. Rather, it is closer to miso. It is said
that the fi rst true production of Hama-natto dates from the
time when Tokugawa Ieyasu became the lord of Hamamatsu
Castle [1568] and wrote instructions to the monks of the
nearby Daifukuji temple.
(a) Production method: The basic ingredients are 100 kg
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HISTORY OF NATTO AND ITS RELATIVES 197
soybeans, 9.2 kg wheat or barley fl our, 18 kg salt, 7.5 kg of
ginger, and koji starter. Large-seeded soybeans, such as those
from the Orani region of Hokkaido or Tsuru-no-ko are used.
The wheat or barley is roasted then ground to a no. 85 mesh
or fi ner fl our. The ginger is thoroughly washed, thinly sliced,
and pickled in shoyu [Japanese soy sauce].
Fig. 8.4 is a fl ow chart of Hama-natto production. First
inspect the large soybeans for any extraneous matter or
imperfect beans, then wash them thoroughly to rid them of
any sand or dirt. Soak in water at 20ºC for 3-4 hours, then
allow to drain for several hours. Steam for 5-6 hours at
normal pressure, then leave overnight in the steaming vat.
The next morning, spread out the beans and allow to cool to
below 40ºC. Then mix in koji starter (tané-koji). Sprinkle the
roasted fl our on top of this and mix the entire mass well.
Spread the mixture evenly in wooden koji trays and
place in a koji incubation room at 30-33ºC for approximately
50 hours to allow the growth of the koji mold. When the
mold has grown suffi ciently, remove the koji rays from the
incubation room and allow to sun-dry outdoors until the
moisture content of 30-35% at the time of removal from
the room, falls to 20-25%, at which point place the mixture
in wooden kegs or small vats. Add enough saltwater (or
shoyu, which is occasionally used) to just cover the molded
soybeans. Place a pressing lid and weight on top of the
mixture, and allow to stand for 6-12 months as it ripens.
After the full fermentation is complete, spread the
mixture out on a cloth to dry in the sun and mix in the
pickled ginger, to make the fi nal product.
Hama-natto is a simple food [or seasoning], dull
blackish in color, but the fl avor is deep and rich, and its
nutritional value and storability are both excellent. Its
percentage nutritional composition is shown in Table 8.10.
Address: National Food Research Inst., Tokyo.
580. Watanabe, Tokuji; Ebine, Hideo; Ohta, Teruo. eds.
1971. Nattô [Natto]. In: Tokuji Watanabe, H. Ebine and T.
Ohta, eds. 1971. Daizu Shokuhin [Soyfoods]. Tokyo: Korin
Shoin. 271 p. See p. 123-38. [Jap; eng+]
• Summary: Continued. The same is also true of 10ºC
and below. Thus, the ideal temperature for the initial
fermentation period of natto is approximately 40ºC, though
in actual production practices the natto bacteria inoculation
takes place at 80ºC and above. This is not only due to the
fact that natto bacteria spores are highly resistant to heat and
lose almost no germination strength at this temperature, but
also because germination proceeds rather more effectively if
the dormant spores are exposed for a short period of time to
high temperature.
For example, if the spores are given a heat treatment
of 100ºC for 10 minutes or 85ºC for 30 minutes, the
germination rate goes up. Of course, once the heat treatment
is completed it is necessary to reduce the temperature to
the optimum germination temperature immediately. Loss of