JP2007159475A - Fermented soybean and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fermented soybean richly containing gamma-aminobutyric acid with no need of considerable labor. <P>SOLUTION: The fermented soybean is obtained through the following process: a process of soaking soybeans in water for about 10 min to wash the soybeans; a process of taking out the soybeans from water, draining the soybeans, transforming the soybeans to a germination bed, intermittently sprinkling water on the soybeans once per several hours under such environment that the room temperature is 15-25°C, and the humidity is 70-90%, preferably 75-85% for about one and a half days or two days so as to germinate the soybeans to grow the germs to have a length equivalent to the half of the soybean or the whole of the soybean; and a process of washing the germinated soybeans, steaming the washed germinated soybeans in a steaming pot, injecting bacillus natto in the steamed germinated soybeans to ferment the soybeans. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to natto and a method for producing natto.

Soybean is a traditional food that has long been known for its usefulness because it has an excellent nutritional balance and contains abundantly healthy ingredients such as high-quality proteins and isoflavones. There are many foods using soybeans, for example, processed foods such as natto, tofu and soy milk.
In recent years, interest in health has increased, and soy has become one of the ingredients attracting attention because of its high nutritional function.

Furthermore, it is known that soybeans produce gamma-aminobutyric acid (GABA Gamma-Amino Butyric Acid) by germination.
This gamma-aminobutyric acid is a component that has recently attracted attention, and it has been clarified by recent studies and the like that it is contained in much in the brain of mammals such as humans and has an action as an inhibitory neurotransmitter. In addition, memory enhancement, blood pressure regulation, kidney and liver activation, and the like have been reported.

  However, soybeans generally have a low germination rate, and such germinated soybeans (germinated soybeans) are difficult to take as they are, so it is necessary to process them. End up.

  The problem to be solved is to ensure germination of soybeans, to make the germinated soybeans easily processed foods, and not to greatly reduce the amount of gamma-aminobutyric acid.

As a result of diligent research, the present inventor has found that when germinated soybeans are processed into natto, about half of the gamma-aminobutyric acid remains before processing, and further, the taste is not lost as natto. Invented.
That is, the most important feature of the present invention is that germinated soybeans that have been germinated after being soaked in water for a short period of time are used as raw materials for natto.

The present invention does not completely rehydrate soybeans during germination of soybeans, soaks them in water for a short period of time, and cleans them while cultivating them while sprinkling to reduce the risk of washing away and breeding germs. And efficiently germinate soybeans.
And since fermented soybeans are made into natto, it contains abundant gamma-aminobutyric acid and has a higher nutritional function than before.
In addition, since the sprouted buds are grown to a certain length, they are low in calories, less odor and easier to eat than the conventional ones.

  Hereinafter, soybean germination processing will be described.

First, the soybean is soaked in water for about 5 to 30 minutes for washing, and a certain amount of moisture is allowed to penetrate into the soybean.
If the soaking time is too short, the soybean does not sufficiently penetrate moisture and the soybean does not germinate, but it is not necessary to fully soak the soybean by soaking it for a long time, reducing the risk of germs growing and In order to shorten the time, an immersion time of about 5 to 30 minutes is appropriate.

  Soybeans with a medium grain selected for bean sprouts have a high germination rate, and germinated soybeans rich in gamma-aminobutyric acid can be obtained efficiently.

After washing, the soybeans are taken out, drained well, and transferred to the germination bed. The germination bed is a shallow dish with a low peripheral wall, with a number of holes for draining that are smaller than soybeans at the bottom.
Because the temperature and humidity may be too high or too low, germination may cause poor germination, so the germination bed should be at an ambient temperature of 15 to 25 degrees Celsius and humidity of 70 to 90 percent, preferably 75 to 85 percent. It is appropriate to leave.

  And it sprinkles and sproutes about once every several hours so that soybean may not dry. By sprinkling water, germination heat of soybean is removed and various germs are washed away. The temperature of water sprayed is suitably 10 to 20 degrees.

  Soybean sprout is grown to a certain length to confirm that it has sprouted to produce gamma-aminobutyric acid, while if it is too long, the content of gamma-aminobutyric acid decreases, and it becomes sprouts. If it is used as natto, the texture and taste of the soybeans will be impaired.

  Soybeans to be used for producing germinated soybeans are almost 100% germinated soy bean sprouts, so there is no need to select them. Select and use.

  Germinated soybeans are steamed and inoculated with natto bacteria and fermented at room temperature of 30 to 40 degrees according to a normal natto production method.

  Next, a specific natto manufacturing process will be described.

First, the soybean is soaked in water for about 10 minutes for washing, and a certain amount of moisture is permeated into the soybean.
Next, in an environment where the room temperature is about 15 degrees and the humidity is about 80 percent, water having a water temperature of about 10 degrees is sprinkled every about 4 hours. Under the above conditions, germination can be confirmed in about 24 hours, and then about 12 to 24 hours until the length of the bud becomes about half to one (about 3 to 8 mm) relative to the soybean. Grow to obtain the desired germinated soybeans.

Then, the germinated soybeans are washed, placed in a steaming pot, and steamed at 110 ° C. and 1 atmosphere for 30 minutes.
Next, the steamed germinated soybean is taken out, inoculated with natto bacteria, fermented for about 24 hours while maintaining the temperature at about 37 ° C, and then aged for about 15 hours by lowering the room temperature to 4 ° C.

  Nutritional components were analyzed and tested for natto produced by the above method and conventional natto. The results are shown in Table 1. All values are numerical values per 100 g of natto.

This inspection was performed by automatic amino acid analysis or high performance liquid chromatography. For lipids, the ether extraction method was used.
The nitrogen / protein conversion coefficient was 5.71, and the energy (kcal) values were converted at 4 kcal / g for proteins and carbohydrates, 9 kcal / g for lipids, and 2 kcal / g for dietary fiber.
In addition, among the values shown in the column of conventional natto, for each item of energy, protein, lipid, sugar, dietary fiber, sodium, moisture and ash, food number 04046, food Quoted from the name "Itobiki Natto".

  The detection limit of gamma-aminobutyric acid is 1 mg. As a result, conventional natto could not be detected.

  As is apparent from Table 1, in natto using germinated soybeans, it can be seen that gamma-aminobutyric acid that could not be detected from conventional natto was produced. In addition, protein, lipid and sugar are decreased, dietary fiber is increased, and the energy value is decreased as a whole, resulting in a low calorie content.

In addition, the flavor is increased by germinating the raw soybean, and the germinated soybean is sufficiently softened by steaming, and the texture of natto is not impaired.
And the natto manufactured by the above method has a white color as a whole, and has a low smell and is easy to eat.

Claims (4)

  Natto made by fermenting germinated soybeans with Bacillus natto.   The natto according to claim 1, wherein the germinated soybeans have buds grown to a length of half to one of the major axis of the soybean. A soaking step of soaking soybeans in water for a period of 5 to 30 minutes;
A germination step of transferring the soybeans after soaking to a germination bed and sprinkling the soybeans intermittently at a frequency of once every few hours in an environment of 70 to 90 percent humidity at a room temperature of 15 to 25 degrees;
A fermentation process for inoculating and fermenting natto bacteria after steaming the germinated soybeans;
A method for producing natto.   4. The method for producing natto according to claim 3, wherein in the germination step, soybean buds are grown to a length corresponding to half to one of the major axis of soybean.