JPH0636733B2 - Koji manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing koji having a target pH.

[Conventional technology]

The soy sauce koji is produced by a method of steaming, roasting, and crushing a protein raw material and a carbohydrate raw material (raw material processing step), and inoculating and culturing the koji mold on this (koji making step).

The koji making step is a step in which the koji mold is used to produce various enzymes required for soy sauce production by using carbohydrates in the raw material as an energy source, and the quality of soy sauce depends on the quality of koji, which is an important step in soy sauce production. It is considered to be one of

Wheat is mainly used as a carbohydrate raw material for producing koji, but even if the quality of wheat is the same, it varies depending on the place of origin, weather conditions, etc., and this variation in quality results in variation in the quality of koji. Have an important effect on.

That is, if the quality of wheat changes, the metabolism of Aspergillus oryzae during the koji making process also changes, and it is not possible to always obtain koji having a uniform quality (particularly, koji pH). Especially, the koji pH is
It is an important factor that seriously affects lactic acid bacteria fermentation and yeast fermentation in the aging process.

Therefore, it is no exaggeration to say that the first step for always obtaining a soy sauce product of uniform quality is to keep the koji pH constant at the end of koji making (during koji).

[Problems to be Solved by the Invention]

Conventionally, as a method for controlling the pH of koji, for example, a method of controlling the water content of koji and the koji-making temperature (Japanese Patent Laid-Open No. Sho 5)
No. 8-126753) is reported, but this method is complicated in operation and has a great influence on other factors such as nitrogen utilization rate other than koji pH, glutamic acid content, etc. Could not be.

[Means for Solving the Problems]

The inventors of the present invention have conducted research to develop a method for making the quality of koji at the time of malting, particularly the malt pH constant, and as a result, it is constant between the degree of gelatinization of the carbohydrate raw material and the malt pH at the end of malting. It was found that the relationship of was established, and the manufacturing method of koji having a controlled koji pH was completed using the relational expression.

That is, the present invention uses the following equation that holds between the koji pH (Y) at the end of koji making and the degree of α-formation (X) of the carbohydrate raw material to determine the koji at the target pH at the end of koji making. A method for preparation, wherein the α-degree (x) corresponding to the target koji pH (y) is determined from the following equation, and the koji-making is carried out using the carbohydrate raw material adjusted to the degree of α (x). , A method for producing koji, wherein the koji of pH (y) is obtained.

Y = -AX + B (In the formula, A and B represent coefficients.) Alternatively, in the method for producing koji, the present invention aims at the degree of gelatinization (X) of the carbohydrate raw material, and the koji pH at the end of koji production ( Y)
It relates to a method for producing koji, characterized in that a carbohydrate raw material is treated so as to have a numerical value obtained by the above equation, and this is used as a raw material for koji making, and koji having a constant pH is prepared. .

In addition, from another point of view, the present invention relates to koji at the end of koji making.
A method for controlling a pH by a carbohydrate raw material, which is obtained from the equation using the above equation that is established between the koji pH (Y) at the end of koji making and the α-degree of hydrolysis (X) of the carbohydrate raw material. The koji pH at the end of koji production is adjusted to the target koji pH (y) by using a carbohydrate raw material having an α-degree (x) corresponding to the target koji pH (y) at the end of koji production as the koji-making raw material. The present invention relates to a method for controlling the koji pH, which is characterized in that

Hereinafter, the method of the present invention will be described in detail.

As used herein, the following terms have the following definitions.

“Koji pH” means the pH of an extract obtained by crushing koji and then extracting it with deionized water.

The "alpha-degree" is a numerical display of the degree of starch alpha-degradation, which includes the reducing sugars produced when koji mold amylase decomposes a carbohydrate raw material that has been subjected to fried rice, etc. It is expressed as a ratio (%) to the reducing sugar produced when the α-carbohydrate raw material is decomposed by koji mold amylase.

The test method was performed according to the method described in "Soy sauce test method" (published by Japan Shoyu Research Institute, 1985), pages 97 to 100.

In the method of the present invention, a raw material used for the production of ordinary soy sauce koji may be used, and for example, a carbohydrate raw material or a mixture of a carbohydrate raw material and a protein raw material is used as a raw material for koji making. Specifically as a protein raw material,
Examples of carbohydrate raw materials such as whole soybean, defatted soybean, wheat gluten, corn gluten, soybean refined protein, and soluble separated protein include wheat, barley, rice, corn, and bran.

If necessary, the raw material for koji making is subjected to pretreatment such as careful selection, washing, dipping, and water spraying, and then subjected to a raw material treatment step.

The characteristic of the method of the present invention in the raw material processing step is that the target koji pH at the end of koji making is used by using the following equation established between the degree of α-formation (X) and the koji pH at the end of koji making (Y). The α-degree (x) of the carbohydrate raw material corresponding to (y) is determined, and the raw material for koji making is treated so that the α-degree of the carbohydrate raw material becomes (x).

Y = -AX + B (In the formula, A and B represent the coefficients.) The coefficients represented by A and B in the above equation vary depending on various conditions during koji making, such as the type of koji mold used and the koji making temperature conditions. For example, when Aspergillus oryzae is used as the koji mold and the static culture method is adopted under the temperature condition of 28 ° C. as the koji-making condition, the coefficients represented by A and B usually show the following ranges.

0.001 ≦ A ≦ 0.01 6.5 ≦ B ≦ 7.5 Therefore, when it becomes necessary to newly change the koji mold to be used and / or the method / condition of the koji mold, a small-scale test is performed for each change. And the coefficients of A and B may be calculated.

As a raw material treating method for the raw material for koji making, a usual method used for producing soy sauce or the like can be used. For example, when the carbohydrate raw material is treated alone, roasting (roasting), steaming, estrouder treatment, etc. may be employed.

When treating the carbohydrate raw material and the protein raw material at the same time, the extruder treatment may be adopted.

The processing conditions of the raw material for koji making may be appropriately selected from the range adopted at the time of soy sauce production so as to obtain the target degree of gelatinization (x). Specifically, when treating a carbohydrate raw material by roasting, by changing the frying temperature, it is possible to obtain a carbohydrate raw material having a different degree of gelatinization. That is, by increasing the roasting temperature, a carbohydrate raw material having a high α-degree can be obtained, and by lowering the roasting temperature, a carbohydrate raw material having a low α-degree can be obtained. The degree of alpha conversion can also be adjusted by previously hydrolyzing or drying the carbohydrate raw material to change the water content. Further, in the case of moist heat treatment such as steaming, the degree of alpha conversion can be adjusted by adjusting the water content of the carbohydrate raw material. That is, even under the same treatment conditions, as the water content of the raw material increases, the high α-carbohydrate raw material is obtained.

The koji-making raw material containing the carbohydrate raw material having the degree of alpha (x) corresponding to the target koji pH (y) thus obtained is
It is used in the next koji making process.

The characteristic of the koji making process of the present invention is that the method adopted when obtaining the relational expression between the koji pH at the end of koji making and the degree of alpha conversion of the carbohydrate raw material
It is either adopting the conditions as they are or adopting methods and conditions very similar to them.

The conditions for the koji making method for obtaining the above relational expression are not particularly limited, and may be appropriately selected from the methods and conditions adopted during soy sauce production.

For example, aspergillus, Aspergillus oryzae,
Aspergillus tamari, Alpergillus soya, etc. can be used. Koji making conditions are temperature 25-40
C., relative humidity of 80% or more, and koji making time of 24 to 60 hours can be appropriately selected from within the commonly used range. The culture method may be any of static culture, ventilation culture, fluidized culture and the like.

Hereinafter, the method of the present invention will be described more specifically by showing experimental examples and examples.

Experimental Example 50 g of defatted soybeans was placed in a glass petri dish with a lid of 45 × 175 mm, water of 60 m was sprinkled to absorb the water, and then heated for 45 minutes under a pressure of 1 kg / cm ² (gauge pressure) using saturated steam. Used as a protein raw material. Next, 50 g of fried and chopped wheat having a degree of gelatinization of 29 to 64% was mixed with this protein raw material, and koji Aspergillus oryzae F- for soy sauce was mixed.
1124 (Microtechnology Research Institute, No. 1365), IFO 43
48 and the same IFO 5240 were inoculated and then cultured in a constant temperature room at 28 ° C. for 44 hours to obtain soy sauce koji. After crushing the total amount of the koji obtained, the pH of the extract obtained by extracting with 10 times volume of deionized water at 15 ° C. for 4 hours was measured with a pH meter. The relationship between the degree of gelatinization of wheat and the pH of koji is shown in FIG.

From Fig. 1, the degree of gelatinization of carbohydrate raw materials and the koji pH at the end of koji making
It was found that there is a negative correlation between and, as expressed by the above equation. Therefore, by using this relational expression, it is possible to easily prepare a koji having a target pH by changing the α-degree of the carbohydrate raw material without changing the koji-making conditions and the like as in the conventional case.

〔Example〕

Example 1 50 kg of defatted soybeans was sprinkled with 75 water to absorb water, and then steamed for 15 minutes at 3 kg / cm ² (gauge pressure) using saturated steam in a pressure steaming can and cooled to 40 ° C. 50 kg of roasted and crushed wheat with a degree of gelatinization of 67% corresponding to the target koji pH of 6.49 obtained from the following formula was mixed, and then Aspergillus oryzae F-112 was used as seed koji.
Inoculate 100 g of the koji culture of No. 4 (Microtechnology Research Institute, No. 1365), and aerate the air at 28 ° C. and 95% relative humidity.
Koji was made for 8 hours. As a result, pH and other component analysis values of the obtained koji were as shown in Table 1.

Y = -0.00815X + 7.034 Example 2 50 kg of defatted soybeans was sprinkled with 75 water to absorb water, and then steamed for 15 minutes at 3 kg / cm ² (gauge pressure) with saturated steam in a pressure steaming can and cooled to 40 ° C. Used as a protein raw material.

Next, from the relational expression shown in Example 1, the target koji pH of 6.3.
The α-degree (79%) corresponding to 9 was obtained, and 50 kg of wheat (water content: 18.4%) was crushed into fried rice to obtain the carbohydrate degree.

The above-mentioned protein raw material and a carbohydrate raw material with a degree of alpha conversion of 79% are mixed, and Aspergillus oryzae F-1124 is added to this.
Inoculate 100 g of the koji culture of (Microtech Lab. No. 1365) with aeration at 28 ° C. and 95% relative humidity while aeration is performed.
Koji was made for an hour. As a result, the pH of the obtained koji was 6.36.

Moreover, when koji was continuously prepared 5 times by the same method as above, the pH of the koji obtained all fell within the range of 6.19 to 6.59, confirming that the method is highly reproducible.

〔The invention's effect〕

The method of the present invention utilizes the relationship established between the degree of gelatinization of a carbohydrate raw material and the pH of koji, and changes the degree of gelatinization of the carbohydrate raw material to obtain a koji having a target koji pH. According to the method of the present invention, it is possible to obtain koji having a pH within a range extremely close to the target koji pH (target koji pH ± 0.2).

Therefore, unlike the conventional method, no special koji-making conditions are required, and a high-quality koji having a target koji pH can be prepared by an extremely simple method.

[Brief description of drawings]

Fig. 1 shows the relationship between the pH of koji at the end of koji making and the degree of gelatinization of the carbohydrate raw material.

Claims (3)

[Claims] 1. A koji having a target pH at the end of koji making is prepared by using the following equation established between the koji pH at the end of koji making (Y) and the degree of α-formation (X) of the carbohydrate raw material. The method is for obtaining the α-degree (x) corresponding to the target koji pH (y) from the following equation, and koji-making is performed using the carbohydrate raw material adjusted to the α-degree (x) to obtain pH ( A method for producing koji, which comprises obtaining the koji of y). Y = -AX + B (In the formula, A and B represent coefficients.) 2. In the production of koji, the carbohydrate raw material is treated so as to have a numerical value obtained by the following equation according to the koji pH (Y) at the end of koji production, which is aimed at the degree of gelatinization (X) of the carbohydrate raw material. Then, use this as a raw material for koji making
A method for producing koji, characterized in that the koji is prepared. Y = -AX + B (In the formula, A and B represent coefficients.) 3. A method for controlling the koji pH at the end of koji making by means of a carbohydrate raw material, which is established between the koji pH (Y) at the end of koji making and the α-degree (X) of the carbohydrate raw material. The koji at the end of koji production is carried out by using an equation and using a carbohydrate raw material having a degree of gelatinization (x) corresponding to the target koji pH (y) at the end of the koji production obtained from the equation as a raw material for koji production. A method for controlling koji pH, which comprises controlling the pH to be a target koji pH (y). Y = -AX + B (In the formula, A and B represent coefficients.)