JP4999750B2 - Long-lasting natto and its manufacturing method - Google Patents

Description

  The present invention relates to a natto that has a long shelf life (a long-term natto) and a method for producing the same.

  In general, in the food field, in order to supply products stably, storage for a certain period may be required in the distribution process, and it is preferable that the shelf life is long. In addition, consumers may keep food in stock and prefer a longer shelf life. This also applies to natto products, and natto that lasts as long as possible is preferable.

In general, natto is produced by washing and dipping soybeans, further steaming, inoculating the obtained steamed soybeans with Bacillus natto, fermenting and aging. And it is reported that when soybean powder (brown soybean) obtained by washing and soaking is added to rice flour and brown rice flour and steamed, natto will last for about 12 to 15 days (patent) References 1 and 2).
Japanese Patent Laid-Open No. 2-119758 JP-A-6-169719

  An object of the present invention is to provide a natto that lasts longer than conventional products and a method for producing the same.

  In order to solve the above problems, the present inventor, while repeating research, disperse insoluble particles in a mixture of cereal powder previously mixed with water, and add the obtained insoluble particle dispersion to steamed soybeans. It has been found that fermenting and ripening results in natto that lasts for a very long period of time, and further research has been conducted to complete the present invention.

That is, the present invention provides a coercive water agent are mixed in water, insoluble particles dispersed in the resulting water-retaining agent mixture, after addition of the dispersion to steamed soybeans, characterized in that fermenting with Bacillus natto, It relates to a method of manufacturing natto.
In the present invention, the water retention agent is rice flour, defatted soybean flour, bran, cellulose, carrageenan, carboxymethylcellulose, xanthan gum, guar gum, tamarind gum, locust bean gum, gellan gum, mannan, psyllium seed gum, alginic acid, alginate, curdlan. The present invention relates to a method for producing natto, comprising one or more selected from pullulan and acacia gum.

Furthermore, the present invention relates to the above-mentioned method for producing natto, wherein the insoluble particles are one or more selected from calcium citrate, calcium carbonate, calcium phosphate, whey calcium, barium sulfate, dolomite, chitin, and chitosan. .
Moreover, this invention relates to the natto manufactured by the said manufacturing method of natto.

  According to the present invention, it is possible to provide natto that lasts for an extremely long period of at least about 20 days without using a preservative or an antioxidant. In addition to long-lasting shelf life, the natto can be provided with a good stringiness by improving the texture and taste by having a soft chewing response while the bean has elasticity.

  As a method for producing natto according to the present invention, a water-retaining agent is mixed with water, insoluble particles are dispersed in the obtained water-retaining agent mixed solution, and the dispersion is added to steamed soybean, followed by fermentation with natto bacteria. Can be used in the production of various thread-drawn natto such as whole soybean natto and ground natto.

  In the present invention, the kind of soybeans or natto bacteria is not particularly limited, and the fermentation process can be performed under the fermentation conditions during normal natto production, but the water-retaining agent and insoluble particles added at the beginning of the fermentation process. It may be changed as appropriate in consideration of the properties and the like.

  The water retention agent used in the present invention is not particularly limited as long as it has no problem as an edible substance and is often entangled with steamed soybeans by mixing with water (including hot water) with an appropriate viscosity, for example, rice flour, Cereal flour such as defatted soybean flour, bran, cellulose, carrageenan, carboxymethylcellulose, xanthan gum, guar gum, tamarind gum, locust bean gum, gellan gum, mannan, psyllium seed gum, alginic acid, sodium alginate, alginate, curdlan, pullulan, Polysaccharides such as gum acacia can be used. As a water retention agent, it is preferable to use grain flour from the viewpoint of compatibility with natto and taste, and it is particularly preferable to use rice flour. The water retention agents may be used alone or in combination of two or more.

The water to be mixed with the water retention agent may be normal temperature, for example, hot water of about 80 ° C. to 98 ° C., and can be appropriately selected according to the properties of the water retention agent. For example, when rice flour or the like is used as a water retention agent, it is heated to about 80 ° C. to 98 ° C. after being added to room temperature water or by heating or after being added to warm water of 40 ° C. to 60 ° C. As a result, the rice flour is gelatinized (α-modified), so that a suitable viscosity can be easily obtained.
The water retention agent is typically mixed at a ratio of about 0.05 to 30% by weight with respect to water. The mixing ratio can be appropriately adjusted depending on the type of water retention agent. For example, in the case of cereal flour such as rice flour, it is preferably mixed at a ratio of 1 to 20% by weight, particularly preferably 3 to 6% by weight. The Moreover, when using polysaccharide as a water retention agent, it is preferable to mix in the ratio of 0.05 to 2 weight%.

The insoluble particles used in the present invention are not particularly limited as long as they are edible and are in the form of particles that can be dispersed in the aqueous water-retaining agent solution, and are not limited to those that are not completely soluble in water, but are hardly soluble in water. Insoluble ones are also included.
Examples of such insoluble particles include calcium citrate, calcium carbonate (fired or unfired eggshell calcium, shell calcium, coral calcium, limestone, etc.), calcium phosphate (fired or unfired, fish bone calcium, beef bone, etc. Calcium-containing compounds such as calcium) and whey calcium (milk calcium), and various materials such as barium sulfate, dolomite, chitin, and chitosan. As the insoluble particles, it is preferable to use calcium carbonate materials such as eggshell calcium, shell calcium, coral calcium, limestone, etc. from the viewpoint of high calcium content, widely used as food, and high safety. Eggshell calcium is preferably used. These insoluble particles can be used alone or in combination of two or more.

In the present invention, the insoluble particles are mixed in a proportion of 1 to 50% by weight, preferably 5 to 30% by weight, particularly preferably 15 to 18% by weight, with respect to the water retention agent mixed solution containing the water retention agent.
Further, the dispersion in which insoluble particles are dispersed in the water retention agent mixture is preferably added in an amount of 3 to 30% by weight, particularly preferably 5 to 20% by weight, based on the steamed soybean. The temperature is, for example, 80 to 95 ° C, preferably 80 to 85 ° C.

  In particular, when a calcium-containing compound is used as insoluble particles, for example, 0.5 to 5% by weight, preferably 0.9 to 3% by weight, with respect to steamed soybeans, from the viewpoint of the effect of calcium bitterness and nutritional reinforcement, Particularly preferably, mixing is performed at a ratio of 1.0 to 2.5% by weight.

Furthermore, the dispersion preferably has an appropriate viscosity when mixed with steamed soybeans. For example, it has a viscosity of 100 to 1000 mPa · s, preferably 180 to 500 mPa · s at 80 ° C. If the viscosity is low, there is a tendency not to adhere well to steamed soybeans. Moreover, when viscosity is high, it may become difficult to mix with steamed soybean and to make it uniform.
Further, the dispersion preferably has a pH of 6.6 to 7.4 from the viewpoint of growth of natto, taste, and the like.

In the present invention, by appropriately selecting a water retention agent and / or insoluble particles, the flavor of natto can be improved or nutritional enhancement can be achieved. For example, when a calcium-containing compound is used as the insoluble particles, the calcium-enriched natto contains more calcium than the conventional product.
The present invention will be described in detail below, but the present invention is not limited to the following examples.

Example 1
4 wt% rice flour was suspended in water, heated well after stirring to prepare a water retention agent mixture. Eggshell calcium was added to the obtained water retention agent mixture so as to be 13.8% by weight. The obtained mixed liquid was heat sterilized at 90 ° C. for 180 minutes to disperse eggshell calcium particles in the liquid (insoluble particle dispersion).
After adding the prepared insoluble particle dispersion at a ratio of 183 g (18.3 wt%) to 1000 g of steamed soybeans, inoculated with natto bacteria, fermented and matured according to conventional methods to produce natto of the present invention did.

(Example 2)
A natto of Example 2 was produced in the same manner as in Example 1 except that barium sulfate was used in place of the eggshell calcium of Example 1 as insoluble particles.

(Comparative Example 1)
5 wt% rice flour was suspended in water, heated well after stirring to prepare a water retention agent mixture.
After adding the prepared water-retaining agent mixture at a rate of 40 g (4.0% by weight) to 1000 g of steamed soybeans, inoculated with natto bacteria, fermented and aged according to a conventional method, and natto of Comparative Example 1 was used. Manufactured.

(Comparative Example 2)
7 wt% rice flour was suspended in water, heated well after stirring to prepare a water retention agent mixed solution.
After adding the prepared water-retaining agent mixture at a ratio of 162 g (16.2 wt%) to 1000 g of steamed soybeans, inoculated with natto bacteria, fermented and matured according to a conventional method. Manufactured. In addition, this comparative example adds the moisture content equivalent to the natto of Example 1. FIG.

(Experimental example 1) Confirmation of shelf life As shown in Table 1 below, changes in the appearance, stringing, aroma and taste after production were observed over time, and the shelf life was examined. The natto after production was stored in a refrigerator at 10 ° C. or 5 ° C., and each index was evaluated by a plurality of skilled panelists. The evaluation criteria for each are as follows.
〔Evaluation criteria〕
Appearance: A Excellent, B Good, C Standard, D Poor Threading: A Excellent, B Good, C Standard, D Poor Fragrance: A Excellent, B Good, C Standard, D Poor Taste: A Excellent, B Good, C Standard , D Poor Overall evaluation: ○ Can be tasted as a product × Cannot be tasted as a product

The natto of Comparative Example 1 was in a state where it could not be tasted as a product when it exceeded 12 days after production. On the other hand, the natto of Example 1 could be tasted as a product even after 22 days after production, and tasted around 20 days. It turns out that there is no problem with the deadline.
About the external appearance, the natto of Example 1 was white as a whole under the influence of rice flour and eggshell calcium.
Regarding thread drawing, the natto of Example 1 was generally superior to the natto of Comparative Example 1 in that the amount of yarn was large throughout the test period.

About fragrance, although both natto of Example 1 and the comparative example 1 changed similarly until the 16th day, the direction of Example 1 was superior after the 16th day.
About taste, both the natto of Example 1 and Comparative Example 1 showed a good taste from the 12th to the 15th day. Moreover, when the natto of comparative example 1 passed the 16th day, fermentation by natto bacteria progressed too much and tyrosine was produced, and it felt intense bitterness, but Example 1 natto produced tyrosine until 22nd day after manufacture. And bitterness was not felt. Further, in terms of the hardness of the beans, the natto of Example 1 had a soft and plump texture when chewed while maintaining elasticity compared to the natto of Comparative Example 1.

Moreover, although not shown in Table 1, in the natto of the comparative example 2, the deterioration of taste may already be confirmed in the 12th day, and it was suggested that fermentation advanced rapidly. This is because even if the same amount of water as in the case of using insoluble particles is added without using insoluble particles, all the water cannot stay on the surface of soybean, and it is difficult to form a water layer. Regardless, it is thought that excessive moisture promotes poor fermentation and accelerated fermentation, and the shelf life is shortened.
In other words, the natto of Example 1 can be added with a moisture amount that has been difficult with water retaining agents only by using insoluble particles, and can retain moisture as a substantially uniform moisture layer. Fermentation could be realized.

Overall, the natto of Example 1 can be sufficiently fermented and matured as a product in the normal fermentation and aging process, while fermentation after production proceeds more than conventional natto. Because it is slow to do, it is expected to last more than 20 days. The following causes are considered for this.
That is, (1) In the natto of the present invention, the fermenting action of the natto 3 with respect to the steamed soybean 1 is reduced when the natto 3 uses the water retaining agent 4 as a nutrient source. Thus, compared with the case where the insoluble particles 5 are not used (FIG. 1 (A)), the insoluble particles 5 together with the Bacillus natto 3 and the water retaining agent 4 are thicker on the surface of the steamed soybean 1 even when the water content is the same. It is conceivable that the moisture layer 2 can be formed and moisture is retained on the surface of the steamed soybean for a longer period of time.

(Experimental example 2) Comparison with Ca containing insoluble particle | grains and Ba containing insoluble particle | grains The comparative examination was carried out about the natto of Example 1 using eggshell calcium, and the natto of Example 2 using barium sulfate.
In both cases, the state when added to boiled beans, the appearance after fermentation, the quality and quantity of yarn, and the like were almost the same, and favorable results were obtained for both. Further, the natto of Example 2 felt slightly softer, and production of tyrosine and bitterness were not felt, and the taste was good.

(A) is a schematic diagram showing natto (Comparative Example 1) produced using only the water retention agent 4, and (B) is a natto (invention) produced using the insoluble particles 5 and the water retention agent 4. It is a schematic diagram shown.

Explanation of symbols

1 Steamed soybean 2 Moisture layer 3 Bacillus natto 4 Water retaining agent 5 Insoluble particles

Claims (4)

  A method for producing natto, comprising mixing a water retention agent with water, dispersing insoluble particles in the obtained water retention agent mixture, adding the dispersion to steamed soybeans, and then fermenting with natto bacteria. Water retention agent is rice flour, defatted soybean flour, bran, cellulose, carrageenan, carboxymethylcellulose, xanthan gum, guar gum, tamarind gum, locust bean gum, gellan gum, mannan, psyllium seed gum, alginic acid, alginates, curdlan, pullulan, acacia gum The manufacturing method of the natto of Claim 1 which consists of 1 type, or 2 or more types selected from. The method for producing natto according to claim 1 or 2 , wherein the insoluble particles are one or more selected from calcium citrate, calcium carbonate, calcium phosphate, whey calcium, barium sulfate, dolomite, chitin, and chitosan. . Natto manufactured by the method for manufacturing natto according to any one of claims 1 to 3 .

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