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

around soy sauce and tofu. J. of the American Oil Chemists’
Society 58(3):346-54. March. [41 ref]
• Summary: Contents: Abstract. Introduction. Soy sauce
varieties: Koikuchi, usukuchi, tamari, saishikomi, and shiro
shoyu. Soy sauce manufacturing process (for each of the 5
types). Miso. Other fermented products: Tempeh and natto.
Tofu and related products: Regular and silken tofu, driedfrozen
tofu, deep-fried tofu. Fermented tofu (Sufu). Other
soy products: Soy milk, fermented soy milk beverages, yuba.
This paper discusses traditional Oriental soy protein
foods which are growing rapidly in popularity in the USA
among non-Asian-Americans.
“Generally speaking, soy sauce is divided into two
groups: fermented soy sauce and chemical soy sauce.
Fermented soy sauce has a long history as a human
food, whereas chemical soy sauce has a history of only
several decades. In fermented soy sauce, the proteins and
carbohydrates contained in the materials are hydrolyzed
very slowly under mild conditions below 30ºC for over six
months, whereas in chemical soy sauce they are hydrolyzed
quickly by hydrochloric acid at 80ºC for 8-10 hours.
Chemical hydrolysis is a cheap and rapid process, but
during the hydrolysis, various secondary reactions occur and
produce undesirable compounds, e.g. dark humins, furfurol,
dimethyl sulfi de, hydrogen sulfi de, levulinic acid and
formic acid, which are not present in fermented soy sauce.
Furfurol, dimethyl sulfi de and hydrogen sulfi de, which have
strong, bad odors in themselves, are derived from pentose,
methionine, and sulfur-containing amino acids respectively.
Furthermore, tryptophane, one of the nutritionally important
amino acids, is destroyed almost completely. As shown in
Figure 1 [two chromatograms], the main organic acid of
fermented soy sauce is lactic acid, whereas the main organic
acid of chemical soy sauce is formic acid. Levulinic acid,
present in chemical soy sauce, does not exist naturally.
“To improve the odors of chemical soy sauce,
semichemical soy sauce was devised. It is made by
hydrolyzing raw soybeans with a lower concentration of
hydrochloric acid (7-8%) as the fi rst step, followed by
fermenting the hydrolysate with osmophilic yeasts in the
presence of wheat koji.” In Japan, chemical soy sauce is not
used as a soy sauce in itself, but as an extender for fermented
soy sauce.
Table 1 gives the typical chemical composition (per 100
ml) of the fi ve varieties of traditional soy sauce in Japan,
including Bé [Baumé; a measure of the relative density of
liquids], sodium (koikuchi is lowest at 17.6%, usukuchi is
highest at 19.2%), total nitrogen (koikuchi has 1.55 gm,
tamari has 2.55 gm or 65% more), formol nitrogen, reducing
sugar, alcohol (koikuchi is 2.2%, by far the highest), pH
(ranges from 4.6 to 4.8), and color.
A brief description of each of the fi ve traditional
varieties: (1) Koikuchi: This “dark-colored” shoyu is by
far the most popular of the fi ve types of fermented soy
© Copyright Soyinfo Center 2012
HISTORY OF NATTO AND ITS RELATIVES 276
sauce in Japan, comprising 85% of the total. It is an allpurpose
seasoning with a strong aroma, complex fl avor,
and deep, reddish-brown color. These characteristics are
mainly derived from the use of equal amounts of wheat and
soybeans in the koji; (2) Usukuchi [light-colored] shoyu is
characterized by a lighter, red-brownish color and a milder
fl avor and aroma. It is used mainly for cooking when one
wishes to preserve the original fl avor and color of the food
itself. As in koikuchi, equal amounts of soybeans and wheat
are used in the koji, but the fermentation is done under
conditions which prevent the development of a dark color.
(3) Tamari shoyu has a higher amino acid content, but it
lacks aroma. The koji is made primarily from soybeans
with little or no wheat. (4) Saishikomi (twice-fermented)
shoyu is made using equal amounts of wheat and soybeans
in the koji, but using raw (unpasteurized) soy sauce instead
of salt solution, which is mixed with the harvested koji.
Saishikomi is characterized by aroma and full-bodied taste.
(5) Shiro (clear, or “white”) shoyu is made by using a very
high ratio of wheat to soybeans in the koji, and further by
fermentation under conditions which prevent dark color
development. It is characterized by a very light yellow to tan
color, though the amino acid content is very low because of
the low soybean content in the koji. Flow sheets show the
process for manufacturing koikuchi, usukuchi, and tamari
shoyu. Each has three basic parts: Koji making process, brine
fermentation process, and refi ning process.
Concerning soy sauce production and consumption:
The total annual production of soy sauce in Japan in 1979
reported by the Japanese Agricultural Standard (JAS) was
1,252,431 kiloliters (kl). In 1979 in Japan, about 70% of the
soy sauce products in Japan were purely fermented, 25%
contained some semichemical soy sauce, and the remaining
5% contained chemical (HVP) soy sauce. The most recent
estimates of annual consumption of soy sauce in the USA are
as follows: Fermented soy sauce 17,850 kl; Chemical (HVP)
soy sauce 25,500 kl. Within fermented soy sauce, production
of koikuchi soy sauce is estimated to be 16,500 kl/year.
In Japan an “instant tofu powder” is actually a spraydried
soy milk. This product was made and introduced by
Nihon Tanpaku Kogyo (Japan Protein Industry) about 15
years ago (ca. 1966) and was used mainly as a raw material
for making regular or silken tofu in order to save time.
“Recently, however [1973], the product was placed on the
market as an instant powdered tofu [named Hausu Hontôfu]
by Hausu [House] Foods Co.”
A photo shows D. Fukushima. Address: Kikkoman
Foods, Inc., Walworth, Wisconsin 53184.
859. Haytowitz, David B.; Marsh, Anne C.; Matthews, Ruth
H. 1981. Content of selected nutrients in raw, cooked, and
processed legumes. Food Technology 35(3):73-74. March.
[11 ref]
• Summary: Contents: Introduction. Peanuts and soybean