JP7354541B2 - Method for producing grain food, method for suppressing quality deterioration, and agent for suppressing quality deterioration of grain food - Google Patents

Description

The present invention relates to a method for producing grain foods, a method for suppressing quality deterioration, and an agent for suppressing quality deterioration of grain foods.More specifically, the present invention relates to a method for producing grain foods, a method for suppressing quality deterioration, and an agent for suppressing quality deterioration of grain foods. The present invention relates to a method for producing grain foods, a method for suppressing deterioration in quality of grain foods, and an inhibitor for suppressing deterioration in quality of grain foods.

Rice foods such as sushi and rice balls made using cooked rice, as well as cereal foods prepared using grains such as rice and wheat, such as bread and udon noodles, are popular products sold at kiosks and convenience stores. . These grain foods are required to maintain quality such as physical properties and texture for a certain period of time after production until they are sold and eaten by consumers. In grain foods, deterioration in physical properties and texture due to aging of starch, which is a main nutrient, has become a problem, and various studies have been conducted to suppress such deterioration in physical properties and texture. It's here.
For example, a new maltotriosyltransferase that acts on polysaccharides and oligosaccharides with α-1,4-glucosidic bonds and has the activity of transferring maltotriose units to sugars is added during bread production and rice cooking. It has been reported that by doing so, a decrease in the degree of gelatinization of starch is suppressed (Patent Document 1).
In addition, a composition for improving cooked rice containing a branched oligosaccharide obtained by allowing α-amylase to act on starch and then acting on maltotriosyltransferase (Patent Document 2), a maltose-producing α-amylase, a branching enzyme and A method for producing a cooked rice product (Patent Document 3) has been reported, which includes a step of contacting rice with an enzyme aqueous solution containing an enzyme selected from the group consisting of a mixture thereof, and a step of cooking the rice.

However, in response to the recent demand for food loss reduction, in order to extend the expiration date of grain foods, there is a need for grain foods to maintain quality such as texture and physical properties for an even longer period of time. Due to this demand, grain foods are increasingly being stored at lower temperatures than before, so there is a need for grain foods that can suppress deterioration in quality such as texture even when stored at low temperatures.

Japanese Patent Application Publication No. 2015-156861 Japanese Patent Application Publication No. 2015-181412 Special table 2015-525564 publication

Therefore, an object of the present invention is to better suppress deterioration in quality such as texture of grain foods and to provide grain foods that maintain good quality even when stored at lower temperatures than before. do.

As a result of intensive studies to solve the above problems, the present inventors found that one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzyme; The present inventors have discovered that by adding glycosyltransferases in combination to grains, deterioration in quality such as cooking of the grains and texture of processed foods can be effectively suppressed, and the present invention has been completed.

That is, the present invention relates to the following.
[1] Includes adding one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzymes and a glycosyltransferase to grain foods. , a method for producing grain foods.
[2] The production method according to [1], wherein the glycosyltransferase is one or more selected from the group consisting of maltotriosyltransferase, branching enzyme, and transglucosidase.
[3] The production method according to [1] or [2], wherein the carbohydrate hydrolase is β-amylase.
[4] The production method according to any one of [1] to [3], wherein the glycosyltransferase is maltotriosyltransferase.
[5] Glycohydrolase and glycosyltransferase are added to grain foods so that the enzyme activity ratio (glycosylhydrolase/glycosyltransferase) is 0.0000001 to 100000000, [1 ] to [4].
[6] Includes adding one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzymes and a glycosyltransferase to grain foods. , a method for suppressing quality deterioration of grain foods.
[7] The inhibition method according to [6], wherein the glycosyltransferase is one or more selected from the group consisting of maltotriosyltransferase, branching enzyme, and transglucosidase.
[8] The method for inhibiting according to [6] or [7], wherein the carbohydrate hydrolase is β-amylase.
[9] The method for inhibiting any one of [6] to [8], wherein the glycosyltransferase is maltotriosyltransferase.
[10] Glycohydrolase and glycosyltransferase are added to grain foods so that the enzyme activity ratio (glycosylhydrolase/glycosyltransferase) is 0.0000001 to 100000000, [6 ] to [9].
[11] Preventing quality deterioration of grain foods containing one or more glycosylhydrolase selected from the group consisting of β-amylase, glucoamylase and maltotetraose-producing enzyme and glycosyltransferase. Suppressant.
[12] The inhibitor according to [11], wherein the glycosyltransferase is one or more selected from the group consisting of maltotriosyltransferase, branching enzyme, and transglucosidase.
[13] The inhibitor according to [11] or [12], wherein the carbohydrate hydrolase is β-amylase.
[14] The inhibitor according to any one of [11] to [13], wherein the glycosyltransferase is maltotriosyltransferase.
[15] Added to grain foods so that the enzyme activity ratio of glycosylhydrolase and glycosyltransferase (glycosylhydrolase/glycosyltransferase) is 0.0000001 to 100000000, [11 ] to [14].

The present invention suppresses the aging of starch, suppresses deterioration in quality mainly due to starch aging, and maintains good texture etc. even when stored at lower temperatures than before. can be manufactured.
Further, according to the present invention, even when stored at a lower temperature than conventionally, deterioration in the quality of grain foods mainly caused by starch aging can be suppressed favorably.
Furthermore, according to the present invention, even when stored at a lower temperature than conventionally, starch aging can be suppressed, and deterioration in the quality of grain foods mainly caused by starch aging can be suppressed favorably. An inhibitor can be provided.

The present invention provides a method for producing a grain food (hereinafter also referred to as "the production method of the present invention") in which starch retrogradation is suppressed and deterioration in quality mainly due to starch retrogradation is suppressed. do.
The production method of the present invention includes adding one or more glycosylhydrolase selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzyme, and a glycosyltransferase to a grain food. including doing.

In the present invention, "cereal food" refers to seeds of grasses such as rice, wheat, barley, rye, and corn, legumes such as soybeans, adzuki beans, and peas, and the seeds are processed for consumption. refers to cooked foods that contain starch as a major nutrient, such as cooked rice, sushi, rice balls, bread, udon, soba, etc. Preferably, those foods that consumers can eat immediately. This refers to food that has been prepared, packaged, and filled into containers so that it can be cooked.

In the production method of the present invention, one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzyme are used.
β-amylase (1,4-α-D-glucanomaltohydrolase) is present in plants and microorganisms, and is located at the second α-1,4-glycosidic bond from the non-reducing end of sugar chains such as starch and glycogen. It is an enzyme that sequentially degrades maltose in its exo form to produce maltose.
Glucoamylase (glucan 1,4-α-glucosidase) is an enzyme that hydrolyzes the α-1,4-bond at the non-reducing end of a sugar chain into an exo form to produce one molecule of glucose.
Maltotetraose-generating enzyme (glucan-1,4-α-maltotetraohydrolase) hydrolyzes the (1→4)-α-D-glucoside bond of starch polysaccharide and continuously releases it from the non-reducing end of the sugar chain. This is an enzyme that removes maltotetraose units.
In the production method of the present invention, one type of carbohydrate hydrolase mentioned above can be selected and used alone, or two or more types can be selected and used in combination, but from the viewpoint of the anti-aging effect of starch, , β-amylase is most preferably used.
β-amylase, glucoamylase, and maltotetraose-producing enzymes can be produced by extracting and purifying them from plants or microorganisms, by producing them using microorganisms such as Aspergillus oryzae, Bacillus subtilis, or by genetic manipulation. Although it can be manufactured and used according to a production method, commercially available enzyme preparations provided by various companies can also be used.

In the production method of the present invention, the glycosyltransferase added together with the above-mentioned carbohydrate hydrolase receives sugar from sugar nucleotides and transfers the sugar to monosaccharides, serine, threonine, etc. in proteins in vivo. An enzyme that catalyzes a reaction.
In the present invention, one type of glycosyltransferase may be used alone, or two or more types may be used in combination.
From the viewpoint of the effect of suppressing starch retrogradation, maltotriosyltransferase, blanching enzyme, and transglucosidase are preferably used as the glycosyltransferase, and maltotriosyltransferase is more preferably used. It is also preferable to use maltotriosyltransferase and branching enzyme in combination.
Maltotriosyltransferase catalyzes the reaction that transfers maltotriose, branching enzyme catalyzes the reaction that produces branched structures of starch and glycogen, and transglucosidase catalyzes the reaction that transfers α-1,4-bonds. It decomposes and catalyzes the transfer reaction to α-1,6-bonds.
Glycosyltransferases can be produced and used by methods such as extraction and purification from plants or microorganisms, production using microorganisms, production methods such as genetic manipulation, etc., but commercially available Enzyme preparations can also be used.

In the production method of the present invention, one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-forming enzyme have an activity of these enzymes per gram of grain food. The total active amount is usually 0.001 unit (U) to 2000 U, preferably 0.01 U to 200 U, more preferably 0.1 U to 20 U.
In addition, β-amylase activity can be measured by the starch saccharification power measurement method, and when reacted at pH = 6.0 to 8.0 and 40°C for 10 minutes, 1 mg of glucose per minute was extracted from soluble starch. The amount of enzyme that generates a reducing power equivalent to 1U is defined as 1U.
Furthermore, glucoamylase activity can be measured by the glucoamylase measurement method, and the amount of enzyme that generates a reducing power equivalent to 10 mg of glucose from soluble starch in 30 minutes under the conditions of pH = 5.0 and 40°C. is defined as 1U.
Maltotetraose-producing enzyme activity can be measured by the Somogyi-Nelson method, and the amount of enzyme that produces reducing sugar equivalent to 1 μmol of glucose per minute is defined as 1 U.

In the production method of the present invention, the enzyme activity of the glycosyltransferase per gram of cereal food is usually 0.000001U to 1000U, preferably 0.00001U to 100U, more preferably 0.0001U to 10U in terms of total activity. It is added as follows.
The enzyme activity of glycosyltransferase can be measured by a known method. For example, the enzyme activity of maltotriosyltransferase can be measured by a 4-α-glucanotransferase power test method, and pH= 6.5. The amount of enzyme that produces 1 μmol of glucose per minute from maltotetraose when reacted at 40°C for 60 minutes is defined as 1 U.
In addition, the enzymatic activity of the blanching enzyme can be measured by the iodine reaction method using amylose. The amount of enzyme that reduces the absorbance by 0.05% is defined as 1U.
The enzymatic activity of transglucosidase can be measured by the maltose decomposition method, and the amount of enzyme that produces 2 μmol of glucose per minute at pH=5.0 and 40° C. is defined as 1 U.

In the production method of the present invention, one or more carbohydrate hydrolases and glycosyltransferases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzyme are It is added so that the enzyme activity ratio (carbohydrate hydrolase/glycosyltransferase) is usually 0.0000001 to 100000000, preferably 0.00001 to 1000000, and more preferably 0.000001 to 100000000. 001 to 10,000.

Furthermore, in the production method of the present invention, glucose A carbohydrate oxidizing enzyme such as oxidase can be added.
Carbohydrate oxidase may be added in an amount of preferably 0.01 U to 10 U, more preferably 0.1 U to 1 U, per 1 g of cereal food.
In addition, the amount of enzyme per 1 g of cereal food relative to the total amount of glycosyltransferase and one or more types of glycosyl hydrolase selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-generating enzyme It is added so that the activity ratio (carbohydrate oxidase/carbohydrate hydrolase and glycosyltransferase) is preferably 0.001 to 1,000,000, more preferably 0.1 to 10,000.

One or more types of carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-generating enzymes, glycosyltransferases, and carbohydrate oxidases are used during the processing or cooking of grain foods. It is preferable to add it in.
The above enzymes may be added directly to grain foods in the form of powder, but in order to add them uniformly to grain foods, they must be dissolved or dispersed in a solvent such as water, and in the form of a solution or dispersion. It is preferable to add. Alternatively, it can also be added as a quality deterioration inhibitor for grain foods, which will be described later.
Depending on the form of the grain food, cooking or processing method, the food or its ingredients may be immersed in the enzyme solution, or the enzyme or enzyme solution or enzyme dispersion may be added to the food or its ingredients and mixed or kneaded. Good too.
The temperature at which the enzyme is added is usually 4°C to 70°C, preferably 10°C to 60°C, more preferably 20°C to 50°C.
The time for mixing, kneading, or immersing after adding the enzyme is usually 1 minute to 24 hours, preferably 10 minutes to 12 hours, and more preferably 20 minutes to 2 hours.
The grain food to which enzymes have been added and which has been treated as described above is prepared by processing, cooking, filling into containers, molding into a desired shape, etc. according to a conventional method, and is stored according to a conventional method. Ru.

The grain food produced by the production method of the present invention suppresses the aging of the starch contained in the grain food, and when stored at a lower temperature than before (for example, about 15°C to 17°C), for example, for 24 to 48 hours. However, the texture and other qualities are well maintained.
Here, "starch retrogradation" refers to a phenomenon in which starch releases water and becomes insoluble when gelatinized starch is cooled, and starch molecules dispersed in water crystallize again. This occurs due to As a result, the texture of processed and cooked grain foods is reduced, for example, the stickiness during chewing is reduced, and the texture becomes hard and lumpy.
Therefore, according to the production method of the present invention, the aging of starch is suppressed, so that the above-mentioned deterioration in texture due to starch aging is effectively suppressed.
The production method of the present invention is particularly preferably applied to the production of cooked rice and foods made using cooked rice (sushi, rice balls, etc.).

The present invention also provides a method for suppressing quality deterioration when grain foods are stored particularly at low temperatures (hereinafter also referred to as "the suppressing method of the present invention" in this specification).
The suppression method of the present invention includes adding one or more glycosyl hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzymes and a glycosyltransferase to grain foods. including doing.
In the inhibition method of the present invention, a carbohydrate oxidase can also be further added.
The grain food, the carbohydrate hydrolase, the glycosyltransferase, and the carbohydrate oxidase, as well as the amount, time, and method of addition of these enzymes to the grain food are as described above in the production method of the present invention.

According to the suppression method of the present invention, even when the grain food is stored at a lower temperature than before (for example, about 15°C to 17°C) for 24 to 48 hours, the aging of starch contained in the grain food is suppressed, Deterioration in quality, such as the texture of grain foods, caused by this is well suppressed.
The suppression method of the present invention is particularly preferably applied to cooked rice and foods manufactured using cooked rice (sushi, rice balls, etc.).

Furthermore, the present invention provides a quality deterioration inhibitor for grain foods (hereinafter also referred to as "the inhibitor of the present invention" in the present specification).
The inhibitor of the present invention contains one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzyme, and a glycosyltransferase.
The cereal food, glycosyl hydrolase and glycosyltransferase are as described above in the production method of the present invention.

The contents of one or more glycosylhydrolase selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzyme, and glycosyltransferase in the inhibitor of the present invention are as described below. It is set appropriately depending on the dosage form of the inhibitor, the type and form of the grain food to be added, etc., but it is set so that in the production method of the present invention, the amount of enzyme that will achieve the above-mentioned enzyme activity for each enzyme can be added. .
Regarding the content ratio of one or more glycosylhydrolase selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzyme and glycosyltransferase in the inhibitor of the present invention, In the production method of the present invention, the above-mentioned addition amount ratio is set so as to be achieved.

The inhibitor of the present invention includes one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzymes, and glycosyltransferases, as well as glycosyltransferases. can contain a quality oxidizing enzyme.
The content of carbohydrate oxidase can also be set so as to achieve the amount added above in the production method of the present invention.

The inhibitor of the present invention can be in a solid form such as a powder, granules, or tablet, and may further contain water, and may be in the form of a solution, emulsion, suspension, dispersion, etc. It can be in liquid form.
As the water, water suitable for food production, such as distilled water, purified water such as ion-exchanged water, and tap water, is used.
Furthermore, the inhibitor of the present invention can also be dissolved or dispersed in water at the time of use.

Furthermore, the inhibitor of the present invention may contain excipients (for example, magnesium carbonate, sugars (glucose, lactose, corn starch, etc.), sugar alcohols (sorbitol, mannitol, etc.), etc.), binding agents, etc., to the extent that the characteristics of the present invention are not impaired. agents (e.g., gelatin, pregelatinized starch, partially pregelatinized starch, cellulose and its derivatives (crystalline cellulose, hydroxypropyl cellulose, etc.), etc.), disintegrants (e.g., crospovidone, povidone, crystalline cellulose, etc.), lubricants ( For example, talc, magnesium stearate, etc.), thickening stabilizers (xanthan gum, sodium carboxymethylcellulose, etc.), emulsifiers (glycerin fatty acid ester, sucrose fatty acid ester, saponin, lecithin, etc.), preservatives (benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, ε-polylysine, etc.), antioxidants (ascorbic acid, erythorbic acid, catechin, etc.), sweeteners (aspartame, acesulfame potassium, licorice extract, etc.), acidulants (citric acid, acetic acid, tartaric acid) ), bittering agents (caffeine, naringin, mugwort extract, etc.), seasonings (sugar, salt, soy sauce, mirin, miso, monosodium L-glutamate, etc.), dashi (kelp soup, bonito soup, mackerel soup, dried sardines) (soup stock, etc.), extracts (seafood extract, meat extract, vegetable extract, seaweed extract, yeast extract, etc.), colorants (annatto pigment, turmeric pigment, gardenia pigment, etc.), fragrances (synthetic fragrances such as ethyl acetoacetate, anisaldehyde, etc.) , spice extracts, natural flavors such as laurel), etc.).
One or more of the above additives may be included as needed, and the content thereof can be set according to the amount normally used of such additives.

The inhibitor of the present invention is prepared by mixing one or more glycosyl hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzymes with a glycosyltransferase, and further comprising a glycosyltransferase. Depending on the situation, carbohydrate oxidase, the above-mentioned additives, water, etc. are added to form solid forms such as powder, granules, and tablets, or solutions, emulsions, suspensions, and dispersions. It can be manufactured according to a general manufacturing method for liquid foods.

The inhibitor of the present invention is added to the cereal food or its ingredients and mixed or kneaded during processing or cooking of the cereal food. When the inhibitor of the present invention is in liquid form, the cereal food or its material may be immersed in the inhibitor of the present invention to allow the enzyme to act on it.
The amount of the inhibitor of the present invention added to grain foods, or the amount used when grain foods are soaked, etc., depends on the dosage form of the inhibitor of the present invention and the content of glycosyl hydrolase and glycosyltransferase. In the production method of the invention, the amount of enzyme that can be added to each enzyme is set so that the enzyme activity described above can be achieved.
The temperature at which the inhibitor of the present invention is added, mixed, kneaded, immersed, etc., and the time during which the inhibitor is mixed, kneaded, immersed, etc. are as described above in the production method of the present invention.

The inhibitor of the present invention can suppress the aging of starch contained in grain foods, and can suitably suppress deterioration in quality such as texture of grain foods mainly caused by starch aging. In particular, by using the inhibitor of the present invention, deterioration in quality of grain foods can be effectively prevented even when grain foods are stored for 24 to 48 hours at lower temperatures than conventional ones (for example, about 15 to 17 degrees Celsius). Can be suppressed.
The inhibitor of the present invention can be particularly preferably used to suppress deterioration in the quality of cooked rice and foods prepared and processed using cooked rice (sushi, rice balls, etc.).

Hereinafter, the present invention will be explained in more detail with reference to Examples.

[Examples 1 to 5, Comparative Examples 1 to 8] Preventing quality deterioration of cooked rice and production of rice balls Wash the rice stored in the refrigerator (repeat the operation of washing 20 times and replacing the water 5 times), and add 400 g of the rice to 400 g of the rice. After adding 540 g of water (hydration rate = 135%) and soaking at 20° C. for 1 hour, rice was cooked in a 3.5-cup rice cooker.
At that time, the enzyme preparations shown in Tables 1 and 2 were added as inhibitors of deterioration in the quality of cooked rice, respectively. In addition, cooked rice cooked without adding the enzyme preparation was used as a control.
After cooking, the cooked rice was vacuum cooled to 23° C., rice balls (80 g/piece) were prepared, wrapped in ordinary hand-wrapped packaging material, and stored at 15° C. for 30 hours (n=2).
The enzyme preparations used are as follows.
(i) β-amylase; “β-amylase F “Amano”” (manufactured by Amano Enzyme Co., Ltd.)
(ii) Maltotetraose-generating enzyme; “Denabake EXTRA” (manufactured by Nagase Sangyo Co., Ltd.)
(iii) Glucoamylase; “Glucoamylase for sake brewing “Amano” SD” (manufactured by Amano Enzyme Co., Ltd.)
(iv) Maltotriosyltransferase; “Glycotransferase “Amano” L” (manufactured by Amano Enzyme Co., Ltd.)
(v) Blanching enzyme; "Blanching enzyme A" (manufactured by Nagase Sangyo Co., Ltd.)
(vi) Transglucosidase; “α-glucosidase L “Amano”” (manufactured by Amano Enzyme Co., Ltd.)
(vii) Glucose oxidase; “SumiTeam PGO” (manufactured by Shin Nippon Chemical Co., Ltd.)
(viii) Transglutaminase; "Activa TG" (manufactured by Ajinomoto Co., Inc.)

The preserved rice balls were eaten by three panelists aged 32 to 37, and the texture (sensitivity of the rice, i.e., freshness, softness, degree of decrease in stickiness during chewing, and grain size of the rice) was evaluated. The participants were asked to perform a sensory evaluation on the rice balls (feel), and to make a comprehensive evaluation on the quality of the rice balls. The evaluation results were scored according to the following evaluation criteria, and the average value of the three participants was calculated.
<Evaluation criteria>
(1) Aging properties of rice I don't feel the aging of cooked rice: 5 points I hardly feel the aging of the cooked rice: 4 points I feel the aging of the cooked rice a little: 3 points I strongly feel the aging of the cooked rice: 2 points I feel the aging of the cooked rice very much Strongly felt: 1 point (2) Grain feel of rice I feel that each grain of rice stands up: 5 points Strongly feel the rice grains stand: 4 points Feel the rice grains stand: 3 points Rice grains Weak texture: 2 points There is no rice grain feel, and there is a kneaded feel: 1 point (3) Overall evaluation Good: 5 points Fairly good: 4 points Average: 3 points Somewhat poor: 2 points Bad: 1 point

The above evaluation results are also shown in Tables 1 and 2 as panel average values.

As shown in Table 1, rice balls made from rice cooked with each of carbohydrate hydrolase, glycosyltransferase, and other enzymes added individually as quality deterioration inhibitors in Comparative Examples 1 to 8 were The texture of the rice balls after storage at 15°C was not much different from that of the rice balls made with the control cooked rice, and the overall texture was rated as average to slightly poor.
On the other hand, as shown in Table 2, the rice balls made with the cooked rice added with the quality-degrading agents of Examples 1 to 5 had good texture even after being stored at 15°C for 30 hours. Overall, it was rated as ``fairly good'' or ``good.''
In particular, β-amylase 0.1U/g rice as a carbohydrate hydrolase, maltotriosyltransferase 0.2U/g rice as a glycosyltransferase, transglucosidase 0.01U/g rice, or blanching enzyme 2.0U When the quality deterioration inhibitor of Example 3 or 5 in combination with /g rice was added, the deterioration in the quality of the rice balls caused by storage at 15° C. for 30 hours was well suppressed.

[Examples 6 to 11] Control agent for suppressing quality deterioration of cooked rice and production of rice balls 500 g of water was added to 400 g of washed refrigerated rice (hydration rate = 125%), and the additives shown in Table 3 were used as suppressors for suppressing quality deterioration of cooked rice. Rice balls were prepared in the same manner as in the above Examples and Comparative Examples, except that an enzyme preparation was added. The rice balls were packaged in normal hand-wrapped packaging and stored at 17°C for 30 hours (n=2). In addition, the case where rice was cooked without adding the enzyme preparation was used as a control.
As in the above Examples and Comparative Examples, panelists were asked to sensory-evaluate the texture of the rice balls after storage and to make an overall evaluation of the quality of the rice balls. The evaluation results are also shown in Table 3 as panel average values.

As shown in Table 3, when the water addition rate was lowered to 125%, rice balls made with the control cooked rice showed very strong staleness after being stored at 17°C for 30 hours, and the overall It was also rated as poor.
On the other hand, by adding each of the quality deterioration inhibitors of Examples 6 to 11 and cooking rice, aging of the cooked rice was well suppressed even when the water addition rate was lowered, and the rice was ranked as "average" to "good". It was recognized that the company received a comprehensive evaluation of . In particular, as an inhibitor of rice quality deterioration, β-amylase, a carbohydrate hydrolase, was added at 0.20 U/g of rice, and glycosyltransferases, maltotriosyltransferase and blanching enzyme, were added at 0.19 U/g each. Rice balls (Example 8) prepared by cooking the rice with 1.90 U/g of rice and 1.90 U/g of rice obtained good evaluations in both texture and overall evaluation.
Based on the above results, β-amylase, maltotrisyltransferase, and blanching enzyme are added to grain foods as a quality deterioration inhibitor in a ratio of these enzyme activities to 1:1:10. It was suggested that this is the most preferable.

As detailed above, even when stored at a lower temperature than conventionally, starch aging is suppressed, quality deterioration mainly due to starch aging is suppressed, and good texture etc. is maintained. The present invention provides a method for producing a grain food.
Furthermore, the present invention provides a method for suppressing quality deterioration of grains, which can effectively suppress deterioration in quality of grain foods mainly caused by starch aging even when stored at lower temperatures than conventionally. can.
Furthermore, according to the present invention, even when stored at a lower temperature than conventionally, starch aging can be suppressed, and deterioration in the quality of grain foods mainly caused by starch aging can be suppressed favorably. An inhibitor can be provided.

Claims (9)

A cereal food comprising adding one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase and maltotetraose-producing enzymes and a glycosyltransferase to the grain food. , wherein the glycosyltransferase is maltotriosyltransferase, or maltotriosyltransferase and blanching enzyme, and the glycosyltransferase and glycosyltransferase are each A production method , wherein the enzyme activity is added so that the total activity amount is 0.1 U to 20 U and 0.2 U to 10 U, and the grain food is boiled rice or a food produced using cooked rice. The production method according to claim 1, wherein the carbohydrate hydrolase is β-amylase. Claim 1: A carbohydrate hydrolase and a glycosyltransferase are added to a cereal food so that the enzyme activity ratio (glycohydrolase/glycosyltransferase) is 0.016 to 69.5 . Or the manufacturing method described in 2. A cereal food comprising adding one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase and maltotetraose-producing enzymes and a glycosyltransferase to the grain food. 1. A method for suppressing quality deterioration of grain food, wherein the glycosyltransferase is maltotriosyltransferase, or maltotriosyltransferase and blanching enzyme, and the glycosyltransferase and glycosyltransferase each contain 1 g of grain food. A method for suppressing the activity of each enzyme, wherein each enzyme activity is added in a total activity amount of 0.1 U to 20 U and 0.2 U to 10 U, and the grain food is boiled rice or a food produced using cooked rice. The method for inhibiting according to claim 4, wherein the carbohydrate hydrolase is β-amylase. Claim 4: A glycosyl hydrolase and a glycosyltransferase are added to a cereal food so that the enzyme activity ratio (glycosyl hydrolase/glycosyltransferase) is 0.016 to 69.5 . or the suppression method described in 5. An agent for inhibiting quality deterioration of grain foods, which contains one or more carbohydrate hydrolases selected from the group consisting of β-amylase, glucoamylase, and maltotetraose-producing enzymes and a glycosyltransferase. The glycosyltransferase is maltotriosyltransferase, or maltotriosyltransferase and branching enzyme , and the glycosylhydrolase and glycosyltransferase each have an enzyme activity per gram of grain food. An inhibitor that is added in a total active amount of 0.1 U to 20 U and 0.2 U to 10 U, and is a grain food that is cooked or processed using cooked rice or cooked rice. The inhibitor according to claim 7, wherein the carbohydrate hydrolase is β-amylase. Claim 7: The glycosyltransferase is added to grain foods so that the enzyme activity ratio between glycosylhydrolase and glycosyltransferase (glycosylhydrolase/glycosyltransferase) is 0.016 to 69.5 . or the inhibitor according to 8.