JP3100910B2 - Natto production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Background of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing natto, and more particularly, to a method for producing natto by adding dead yeast to a natto raw material to thereby reduce the peculiar natto smell and having the original taste of natto. It relates to a manufacturing method.

[0002]

[Summary of the Invention]

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing natto that can supply extremely low-odor natto at a low cost, based on the problems of the prior art. is there.

[0004]

[Specific description of the invention]

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for producing natto according to the present invention comprises:
As described above, dead yeast is added to the natto raw material, and the use of the dead yeast cells improves the natto smell extremely simply and inexpensively.

The soybeans used as a natto raw material are not particularly limited, but small or medium-sized seeds smaller than large soybeans (such as Tsurunoko soybeans) normally used for cooking are selected, dried well, and the ones having a uniform grain size are selected. Are suitable.

The dead yeast used in the present invention is not particularly limited as long as it is an industrially available and edible dead yeast, and is, for example, surplus yeast produced as a by-product during beer production. And those obtained by physically or chemically killing a so-called brewer's yeast or a baker's yeast or a torula yeast used in bread production (all are commercially available from brewing companies). The dead yeast to be used is usually one kind, but may be used by mixing several kinds as necessary. Here, the physically killed yeast includes, for example, yeast cells that have been killed by heat, pressure, ultrasonic waves, γ-rays, grinding, etc., and the chemically killed yeasts include, for example, organic yeasts. Examples include yeast cells killed by a solvent. Among them, "dried dead yeast" which is widely marketed and easily available and which has been killed by drying heat is preferable.

The present invention is characterized by adding dead yeast cells to the natto raw material, and is basically the same as the conventional natto manufacturing process except for the step of adding dead yeast. That is, the present invention specifically relates to a conventional natto production method in which raw soybeans are immersed in water overnight, drained, steamed under normal pressure or pressure, fermented and matured after inoculation with natto bacteria. The method is not particularly limited as long as it is a method in which the basic steps according to the above are carried out and the dead yeast cells coexist with soybean as a raw material. The fermentation step usually includes a high temperature fermentation in the first half (usually about 4 to 6 hours at 40 to 50 ° C.) and a low temperature fermentation in the second half (usually about 10 to 16 hours at 30 to 40 ° C.), followed by an aging step (usually 2 to 2 hours). At 10 ° C. overnight).

With regard to the timing of adding yeast, it is preferable to add yeast at the start of fermentation (including at the time of inoculation of Bacillus natto and immediately before and after) in consideration of handling during the production process, yield of dead yeast to be used, and the like. Generally, if desired, it can be added during soybean steaming (including before and after steaming) or during the fermentation or ripening process. In view of the effect of reducing the natto odor, it is more preferable to add the dead yeast at the start of fermentation or during fermentation. It should be noted that the dead yeast may be added to the natto raw material (in the present invention, the material before the addition of the yeast is referred to as natto raw material) after the ripening, or the natto may be stored or transported and stored after the addition. Odor can be reduced, and the production method of the present invention includes such an embodiment.

[0010] The amount of the dead yeast to be added is 0.2 to natto raw material, preferably soybean after steaming (including after fermentation).
It is 10% by weight, preferably 0.5 to 5% by weight. 0.
If the amount is less than 2% by weight, the desired effect of the present invention, ie, the reduction of natto odor, cannot be sufficiently exhibited. Not preferred.

Although the mechanism of action of reducing the natto odor by the addition of dead yeast as described above has not been fully elucidated, it is important that the complex of yeast-derived polysaccharide, protein and lipid retains and masks putrefaction odor. Expected, JP-A-59-68
As described in JP-A-56-56 and JP-A-60-164452, the mechanism of action is considered to be different from masking by the fermentation action of yeast.

In the present invention, by adding dead yeast, not only the intended purpose of reducing the natto smell, but also yeast-derived vitamins B1, B2,
Add various vitamins and minerals such as niacin to supplement natto-containing nutrients,
A healthy natural food with extremely high nutritional value can be created.

[0013]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the technical scope of the present invention. [Sensory Evaluation Criteria] The sensory evaluation shown in the following Comparative Examples and Examples was carried out by 10 panelists. The sensory evaluation of each experimental section of Example 1 was performed according to Table 1 based on the target section prepared in Comparative Example 1 for each item, and the average was shown. Table 1: Scoring criteria for sensory evaluation Very good +2 Somewhat good +1 Equivalent 0 Somewhat bad -1 Very bad -2

Comparative Example 1 250 g of small-grain soybeans were immersed in water overnight at 8 ° C.
1.5kg / cm ² ), steamed under pressure and steamed soy 500g
Was prepared. To this steamed soybean, about 2 commercially available dried natto cells
After dispersing 0 mg in 40 mL of hot water (about 70 ° C), the mixture was inoculated and mixed, and fermented at 45 ° C for about 6 hours. After lowering the fermentation temperature to 40 ° C and fermenting for about 14 hours,
It was aged for days to prepare natto.

[Example 1] To 500 g of steamed soybean prepared in the same manner as in Comparative Example 1, 0.2% (1 g) of dried dead yeast (dry beer yeast manufactured by Kirin Brewery), 0.5%
% (2.5 g), 1% (5 g), 5% (25 g), 10%
% (50 g), and inoculated with Bacillus natto in the same manner as described above, and fermented at 45 ° C. for about 6 hours. Then 4
After lowering the fermentation temperature to 0 ° C and fermenting for about 14 more hours,
It was aged at 4 ° C. for 3 days to prepare natto. The obtained natto was subjected to a sensory evaluation test (Table 2). From the results of the sensory evaluation shown in Table 2, the effect of adding the dried and dead yeast on the improvement of natto smell, taste and stringiness was confirmed, and good results were obtained in the comprehensive evaluation. In particular, the improvement effect of adding 1 to 5% of dried dead yeast was remarkable. Table 2 Experimental plot (addition of yeast) Odor Taste Quality Itohiki Comprehensive evaluation 0.2% addition section +0.6 +0.20 +0.4 0.5% addition section +0.8 +0.6 +0.2 +0.8 1% addition section +1.4 +1.0 +0.6 +1.2 5% addition section +1.4 +1.3 +1.2 +1.3 10% addition section +0.6 +1.2 +1.0 +0.6

Further, the concentration of ammonia in 1000 ml of the prototype natto odor was measured using Model 801 manufactured by Gastech. As shown in Table 3, it was observed that the addition of the dried killed yeast effectively reduced the ammonia volatilized from natto. Table 3 Experimental plot (yeast added) 0% 0.2% 0.5% 1% 5% 10% Ammonia concentration (ppm) 12 6.5 5 4.5 5 2

[0017]

According to the present invention, it is possible to provide a method for producing natto which can reduce the odor peculiar to natto simply and inexpensively by incorporating dead yeast into the raw material of natto. According to the production method of the present invention, in addition to reducing the natto smell, in addition to improving the original flavor and taste quality of natto, various vitamins and minerals possessed by the dead yeast are added, and natural nutrition with extremely high nutritional value is provided. It is possible to create food.

Continuation of the front page (56) References JP-A-59-6856 (JP, A) JP-A-60-164452 (JP, A) JP-A-50-125055 (JP, A) JP-A-2-87494 (JP) , U) JP-B-31-37 (JP, B1) JP-B-34-8889 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) A23L 1/20

Claims (4)

(57) [Claims] A method for producing natto, characterized by adding dead yeast cells to natto raw materials. 2. The method for producing natto according to claim 1, wherein the dead yeast cells are dried dead yeast cells. 3. The method according to claim 1, wherein the dead yeast cells are added to steamed soybeans in an amount of 0.2
The method for producing natto according to claim 1 or 2, wherein the natto is added in an amount of from 10 to 10% by weight. 4. The method for producing natto according to claim 1, wherein the dead yeast cells are added at the start of fermentation or during the fermentation process.