JP2006149306A - Method for producing fermented soybean easy to eat and fermented soybean produced by the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing fermented soybeans easy to eat, capable of adjusting smell, stickiness and bitterness peculiar to fermented soybeans without spoiling favorable flavor which fermented soybeans have, and to provide the fermented soybeans produced by the method. <P>SOLUTION: This method for producing the fermented soybeans easy to eat comprises a washing process of washing raw material soybeans, a soaking process of supplying the soybeans with water by soaking in water, a steaming process of steaming after draining water and a fermenting process of inoculating Bacillus natto followed by fermenting. In the processes, alkali treatment is performed between the soaking process and the steaming process. The fermented soybeans produced by the method are subjected to acid treatment and heat treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to natto and a method for producing natto, and more particularly to a method for producing natto that is easy to eat and capable of adjusting the odor, stickiness, or bitterness peculiar to natto, and to natto produced by the method.

  Natto is a very good food with good digestibility and high nutritional value. In order to increase consumption of such nutritious natto, it is an extremely effective means to use it as a wide variety of ingredients for natto as a new use.

  Below, the manufacturing process of the conventional natto is demonstrated.

  FIG. 4 is a diagram showing a conventional natto manufacturing process.

  That is, first, soybeans as a raw material are washed (washing step 11), and dipped in water to supply water (dipping step 12). After soaking, the water is drained, placed in a steaming pot and steamed (steaming process 13). Subsequently, the steamed soybean obtained is cooled and then inoculated with natto bacteria and fermented (fermentation step 14) to obtain natto (n). Conditions such as temperature and time in each step are not particularly limited according to a normal method.

  However, since natto has unique odor (ammonia-like odor), stickiness, and bitterness, many people refrain from natto, which is an obstacle to expanding consumption of valuable foods. In addition, the stickiness peculiar to natto makes it difficult to handle when processing it as an ingredient in side dishes.

  Many proposals have been made to remove the cause of these natto being shunned.

  For example, as a method for reducing the ammonia-like odor, a method for reducing the odor of natto by adding tea leaves or a catechin compound has been proposed (see, for example, Patent Document 1).

  Moreover, in order to remove the stickiness of natto, a method has been proposed in which water or edible powder is added to natto and the sticky substance is removed using this as a medium (see, for example, Patent Document 2).

Furthermore, natto fried chicken has been proposed in which the odor unique to natto and the adhesive force called normal yarn are removed or alleviated by heating (for example, see Patent Document 3).
JP-A-8-173077 JP-A-8-84569 JP-A-9-322743

  However, in the method described in Patent Document 1, by adding tea leaves or a catechin compound, the unique ammonia-like odor of natto can be reduced, but the stickiness cannot be adjusted. Also, bitterness cannot be adjusted.

  Moreover, in the method described in the said patent document 2, although the peculiar stickiness which natto has can be removed, an odor and bitterness cannot be adjusted. In addition, since the sticky material that causes stickiness of natto is removed by adding edible powder such as water or starch to natto, the natto after treatment is in a state where the natto surface is wet or edible powder is on the natto surface. There is a problem that it is obtained in an attached state, and is not suitable for the case where the processed natto is used as ingredients for sugar beet.

  Furthermore, in the method described in Patent Document 3, the odor and adhesive strength are reduced to some extent by heating, but there is a problem that the degree is insufficient. Also, bitterness cannot be adjusted.

  The present invention has been made in view of such problems, and the purpose of the process is to adjust the characteristic odor, stickiness or bitterness without damaging the preferred flavor of natto and to make it easy to eat. And to provide natto produced by the method.

  The present invention has achieved the above object by the following technical configuration.

  (1) In the natto manufacturing process including a washing process for washing raw soybeans, a soaking process in which water is soaked in water, a steaming process in which water is cut and steamed, and a fermentation process in which natto bacteria are inoculated and fermented, the soaking process A method for producing easy-to-eat natto, characterized in that alkali treatment is performed during the cooking process.

  (2) In the natto manufacturing process including a washing process for washing raw soybeans, a soaking process in which water is soaked in water, a steaming process in which water is cut and steamed, and a fermentation process in which natto bacteria are inoculated and fermented, the soaking process A method for producing easy-to-eat natto, characterized in that ascorbate treatment or ascorbic acid treatment is carried out during the cooking process.

  (3) Natto manufactured by a natto manufacturing process including a washing process for washing raw soybeans, a dipping process in which water is soaked in water, a steaming process in which water is cut off and steamed, and a fermentation process in which natto bacteria are inoculated and fermented. And an easy-to-eat natto production method, characterized by performing an acid treatment and a heat treatment.

  (4) An easy-to-eat natto production method, wherein the natto produced by the easy-to-eat natto production method described in (1) is subjected to an acid treatment and a heat treatment.

  (5) An easy-to-eat natto production method, wherein the natto produced by the method for producing easy-to-eat natto described in (2) is subjected to acid treatment and heat treatment.

  ADVANTAGE OF THE INVENTION According to this invention, the characteristic smell, stickiness, or bitterness can be adjusted without impairing the preferable flavor which natto has, and the method of manufacturing natto which is easy to eat and the natto manufactured by this method can be provided.

  Examples of the present invention will be described below.

  The alkali treatment according to the present invention will be described below. FIG. 1 is a diagram illustrating a manufacturing process of natto according to the first embodiment.

  Except for the alkali treatment (A) according to the first embodiment, since the conventional natto manufacturing method is used, the steps other than the alkali treatment (A) are denoted by the same reference numerals and the description thereof is omitted.

  This process is performed to adjust the bitterness of natto.

Alkaline treatment (A) is performed after the immersion process of the conventional manufacturing process of natto. That is, soybeans as a raw material are immersed in water, and then placed in water at 90 to 95 ° C. to which sodium bicarbonate (sodium bicarbonate: NaHCO ₃ ) is added, and blanched for 30 to 60 seconds. The ratio of water and the raw material soybean is 1 soybean to 5 water.

  The sensory test was done about natto (n1) obtained as a result of performing the said process. The results are shown in Table 1.

  When the pH of the water during the alkali treatment was 7.7 or higher, bitterness could be reduced and removed. However, since the preferable flavor which natto has will be impaired when pH exceeds 7.95, the range of pH 7.7 to 7.95 is especially preferable. In Example 1, sodium bicarbonate was added to adjust the pH of water, but the present invention is not limited to this.

  By the alkali treatment (A), the specific bitterness can be adjusted without impairing the preferred flavor of natto.

  Natto (n1) obtained in Example 1 may be further subjected to acid treatment and heat treatment described below.

  The ascorbate treatment according to the present invention will be described below. FIG. 2 is a diagram illustrating a manufacturing process of natto according to the second embodiment.

  Except for the ascorbate treatment (B) according to Example 2, since the conventional method for producing natto is performed, the steps other than the ascorbate treatment (B) are denoted by the same reference numerals, and the description thereof is omitted.

  This process is performed to adjust the bitterness of natto.

  The ascorbate treatment (B) is performed at the same timing as the alkali treatment of Example 1. That is, after soaking the soybean as a raw material in water, soybean and Na ascorbate as ascorbate are added to the boiled water and boiled for 60 seconds. The ratio of water and the raw material soybean is 1 soybean to 5 water.

  The sensory test was done about natto (n2) obtained as a result of performing the said process. The results are shown in Table 2.

  The bitterness was changed when the Na ascorbate concentration was 0.05% or more. In particular, the bitterness was suitably reduced and removed at 0.15% or more. However, if it is 0.25% or more, the preferred flavor of natto is impaired, so a concentration range of 0.15 to 0.25% is particularly preferable.

  By the ascorbate treatment (B), the specific bitterness can be adjusted without impairing the preferred flavor of natto.

  In this example, ascorbate was used, but ascorbic acid may be used. In that case, the concentration of ascorbic acid is preferably in the range of 0.13 to 0.23%.

  Natto (n2) obtained in Example 2 may be further subjected to acid treatment and heat treatment described below.

  The acid treatment and heat treatment according to the present invention will be described below. FIG. 3 is a diagram illustrating a manufacturing process of natto according to the third embodiment.

  The natto used for the acid treatment and the heat treatment may be the one subjected to the alkali treatment of Example 1 or the ascorbate treatment of Example 2 (n1 or n2), or may not be (n). In this example, natto (n) not subjected to alkali treatment (A) or ascorbate treatment (B) was used.

  The acid treatment (C) and the heat treatment (D) according to Example 3 are performed to adjust the odor and stickiness of natto.

  An organic acid was added to natto (n), allowed to stand for a predetermined time, and then heated with steam at 100 ° C.

  In this example, commercially available rice vinegar (4.2%) was used as the organic acid to be added. However, the present invention is not particularly limited to this, and foods such as citric acid, acetic acid, lactic acid, malic acid, and gluconic acid are used. Are used as usual.

  Heating was performed for 5 to 10 minutes with steam at 100 ° C. and a center temperature of 90 ° C.

  The sensory test was done about natto (n3) obtained as a result of performing the said process. In the sensory test, rice vinegar was added to natto (n), stirred 50 times with chopsticks, then allowed to stand for 5 minutes, quality evaluation, heating, cooling, and quality evaluation. The results are shown in Table 3 (heating time 5 minutes) and 4 (heating time 10 minutes). In addition, Table 5 shows the results for natto that was subjected to only acid treatment and no heat treatment as a control group.

  From Table 5, it was found that the viscosity cannot be adjusted when the heat treatment (D) is not performed. Further, even when the amount of rice vinegar added was 5%, an ammonia-like odor remained. On the other hand, when the amount of rice vinegar added was 2% or more, the smell of vinegar remained, and there was a disadvantage that the acidity was felt when 3% or more.

  From Table 3, when the heating time was 5 minutes, the amount of rice vinegar added was 3% or more, the ammonia-like odor disappeared, and the stickiness also decreased. Moreover, the smell of vinegar was not left and the acidity was only slightly felt.

  From Table 4, when the heating time was 10 minutes, the amount of rice vinegar added was 1% or more, the ammonia-like odor disappeared, and the stickiness also decreased. Moreover, the smell of vinegar did not remain and the acidity was slightly felt at 3% or more.

  From the above, the heating temperature is preferably 90 ° C to 100 ° C. A heating temperature of 90 ° C. or lower is not preferable because it takes too much time to reduce and eliminate stickiness and odor, and the texture of soybeans is impaired. Moreover, in the case of 100 degreeC or more, since temperature is too high and the texture of soybean will be impaired, it is unpreferable.

  The heating time is preferably 5 minutes or more. However, when heated for 10 minutes or longer, the preferred flavor of natto is lost, and 5 to 10 minutes is particularly preferable.

  The amount of rice vinegar added is particularly preferably 3% or more, that is, the amount of acid added is preferably 0.126% or more.

  As described above, the stickiness and odor of natto can be adjusted by acid treatment (C) and heat treatment (D).

  In addition, since the stickiness of this natto is reduced or eliminated, it is very easy to handle in processing when using it as a component of sugar beet, and the effect of increasing the use efficiency of natto can be obtained.

  In addition, when acid treatment (C) and heat treatment (D) are performed using natto (n1, n2) that has been subjected to alkali treatment (A) or ascorbate treatment (B), odor, stickiness, bitterness Natto (n1a, n2a) that is easy to eat and easy to handle during processing can be obtained.

The block diagram which shows the manufacturing process of natto concerning Example 1 The block diagram which shows the manufacturing process of natto which concerns on Example 2. The block diagram which shows the manufacturing process of natto concerning Example 3 Block diagram showing the conventional natto manufacturing process

Explanation of symbols

11 Washing process 12 Immersion process 13 Steaming process 14 Fermentation process A Alkaline treatment B Ascorbate treatment C Acid treatment D Heat treatment

Claims (10)

  In the natto manufacturing process, including a washing process for washing raw soybeans, a soaking process in which water is soaked in water, a steaming process in which water is drained and steamed, and a fermentation process in which natto bacteria are inoculated and fermented, the soaking process and the steaming process An easy-to-eat natto production method, characterized in that alkali treatment is performed during the period.   In the natto manufacturing process, which includes a washing process for washing raw soybeans, an immersion process for immersing in water and supplying water, a steaming process for draining and steaming, and a fermentation process for inoculating and fermenting natto bacteria, the soaking process and the steaming process A process for producing easy-to-eat natto, characterized in that ascorbate treatment or ascorbic acid treatment is performed during the period.   The natto produced in the natto manufacturing process includes a washing process for washing raw soybeans, a soaking process in which water is soaked in water, a steaming process in which water is drained and steamed, and a fermentation process in which natto bacteria are inoculated and fermented. A method for producing easy-to-eat natto, characterized by performing treatment and heat treatment.   A method for producing edible natto, wherein the natto produced by the method for producing edible natto according to claim 1 is subjected to acid treatment and heat treatment.   An easy-to-eat natto manufacturing method, wherein the natto manufactured by the easy-to-eat natto manufacturing method according to claim 2 is subjected to acid treatment and heat treatment.   The method for producing edible natto according to claim 1, wherein the pH of the solution in the alkali treatment is in the range of 7.7 to 7.95.   The ascorbate concentration in the ascorbate treatment is in the range of 0.15% to 0.25%, and the ascorbic acid concentration in the ascorbic acid treatment is in the range of 0.13% to 0.23%. The method for producing easy-to-eat natto according to claim 2.   The method for producing edible natto, wherein the acid addition amount in the acid treatment according to any one of claims 3 to 5 is 0.126% or more.   The method for producing edible natto according to any one of claims 3 to 5, wherein the heating temperature in the heat treatment is 90 to 100 ° C, and the heating time is 5 to 10 minutes.   A natto produced by the method for producing edible natto according to any one of claims 1 to 9.