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東京帝国大学農科大学紀要 第五巻第二号
JOURNAL OF THE COLLEDGE OF AGRICULTURE, IMPERIAL UNIVERSITY OF TOKYO
Vol. 5, No. 2, 1913 p.189

On Bacillus Natto

BY Shin Sawamura
**
Natto is an article of food prepared by leaving soy-beans wrapped in rice straw in a warm place for a night, and thus making then ferment. Soy-beans of natto are coated with a characteristic slimy substance. The author separated formerly two species of bacilli from natto obtained in Tokyo, No. 1 of which produced good flavored natto when inoculated to boiled soy-beans, No. 2 strongly slimy one. The former bacillus was considered to be the chief actor in natto fermentation and received the name of “Bacillus natto”. later years the author examined bacteriologically many samples of natto obtained at various localities, and found that the producer of natto is the same in all cases, viz. “Bacillus natto”. This bacillus can produce natto of good flavor and strong viscosity, and the presence of other microbes is not necessary in the fermentation of natto. The bacteriological description of Bacillus natto is as follows.
(中略)
It was confirmed by the previous investigation that Bacillus natto produces a trypsin-like enzym, and decompose protein of soy-beans. In order to know how protein is decomposed by this bacillus, boiled soy-beans were inoculated with this bacillus, and kept at 35℃, one sample for 14 hours and the other for 7 days. The viscosity and flavor of natto thus prepared are stronger in the younger than in the elder.

The nitrogen in various forms and soluble organic matter in the percentage of dry matter were found to be as follows:-
(成分表を略す)

Soy-bean contains nitrogen chiefly in the form of protein (85-90%), non-albuminous nitrogen being very little (10-15%).

Bacillus natto produces diastase, but reducing sugar was not found in natto thus prepared. This is probably due to the fact that soy-beans do not contain much starch, the main part of carbohydrate being in the form of galactan, &c, wherefore the little glucose formed was decomposed again by the bacillus.

The author expresses hereby sincere thanks to Mr.OSHIMA, assistant of the college, who analysed natto as above mentioned.
**
Bulletin of ariculture College, Tokyo. Vol.7, p.107
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