JPS596856A - Preparation of low-odor natto - Google Patents

Abstract

PURPOSE:To prepare NATTO (fermented soybeans) having low odor, by carrying out the fermentation of soybeans using yeasts as well as Bacillus natto. CONSTITUTION:NATTO is prepared by using yeasts as well as Bacillus natto for fermentation. For example, 60kg of soybean is washed thoroughly with water, and immersed in water for 6-24hr. The immersion is preferably carried out at low temperature for a long period. The immersed soybeans are boiled at <=1 atm for 1hr, and allowed to cool. When the boiled soybean is cooled to >=40 deg.C, a microbial solution obtained by immersing 5ml of a liquid of Bacillus natto and 2g of dried yeast in 1-2l of sterilized water, is inoculated in the boiled soybean. The soybean is maintained at 28-30 deg.C for 3-4hr, and then at 40-45 deg.C for 12-13hr to effect the fermentation. The fermented soybean is cooled to normal temperature and then in a refrigerator for 12hr. The obtained NATTO has rather fragrant smell instead of the ammonia-like stinking odor of NATTO prepared by conventional process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing low-odor natto using yeast.

Although natto is a nutritionally excellent food, it is fermented by natto bacteria, and as protein decomposition progresses, it produces a putrid odor. Because of this odor, many people cannot eat it even though it is highly nutritious. This tendency is especially common in the Kansai area.

One way to counter this is to release natto early without fully fermenting it, but this does not bring out the natural taste of natto.

As a result of various studies, the inventors of the present invention have found that fermentation using both Bacillus natto and yeast can yield delicious natto with less bad odor.

That is, the present invention relates to a method for producing natto with a low odor, which is characterized in that fermentation is carried out by adding yeast bacteria together with natto bacteria during the production of natto.

In the present invention, there is no odor due to the synergistic effect of Bacillus natto and yeast.In the method of the present invention, the product is obtained by following the conventional natto manufacturing method, except that yeast is further added as a fermenting bacterium to carry out fermentation. Therefore, there is no need to make major changes to the conventional manufacturing method.

The yeast used in the method of the present invention may be any yeast. Further, it is preferable to add it at the beginning of fermentation, for example, when suspending the Bacillus natto starter in sterilized water, the yeast is suspended at the same time.

There are no restrictions on the type of yeast used (dry yeast (Iff)
(15 to 100 million viable bacteria per serving) Approximately 2i per 60k of raw soybeans is good.

One of the conditions that greatly affects the performance of the method of the present invention is temperature. An example of the method of the present invention is as follows. After setting the family temperature to about 28° to 30°C, the yeast growth temperature, and allowing sufficient reproduction for 3 to 4 hours, raise the temperature to about +40°'-45°C and hold it for 13 to 14 hours.
You can get natto with less bad odor.

When yeast grows in the method of the present invention, it emits an aroma. After this time has elapsed, if the soybean fungus is allowed to propagate, the resulting product will have less bad odor.

The method of the present invention can also be applied to a method of obtaining natto with less bad odor as shown in Japanese Patent No. 1009632, and a method of obtaining natto with additives other than soybeans such as pearl barley and peanuts.

Further, in order to carry out the method of the present invention, it is necessary to carry out the process at a relatively low temperature, and examples will be shown below.

Example 1 60 ky of soybeans were thoroughly washed with water and soaked in water for 6 to 24 hours. It is preferable that the immersion water be kept at a low temperature for a long time.

The soybeans were steamed for 1 hour at a pressure of 1 atm or less, the steaming was stopped, and the soybeans were crushed when the temperature of the steamed soybeans reached 40C or higher. Inoculation was carried out by adding 5 d of Bacillus natto liquid and 21 dried yeast to the soybeans that had been soaked in sterilized water 1-21 and steamed.

At room temperature 28°~30tG for 3~4 hours, then at 40°~45
After being kept at C for 12-13 hours, I ran away from home.

Next, it was cooled to room temperature and then cooled in a refrigerator for 12 hours.

The resulting product had less malodor, such as ammonia, and was more aromatic than those made using conventional methods.

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Claims (1)

[Claims] A method for producing natto with a low odor, which is characterized by adding yeast bacteria together with natto bacteria to ferment the natto.