JP2020130039A - Novel uses of branching enzymes in dough or dough-heated foods - Google Patents

Abstract

To provide novel uses of branching enzymes in dough or dough-heated foods.SOLUTION: Provided are an agent for improving storage resistance of steamed dough foods, which contains a branching enzyme as an active ingredient, under heating and humidification, and a texture-improving agent for dough-heated foods, and a mechanical resistance-improving agent for dough, as well as a method for producing dough, a method for producing dough-heated foods, and a method for producing dough-steamed foods using the same. According to the present invention, it is possible to contribute to the improvement of product value and the improvement of productivity in the production of dough or foods using the dough.SELECTED DRAWING: Figure 2

Description

The present invention relates to novel uses of branching enzymes in dough or dough cooked foods. Specifically, an agent for improving the storage resistance of steamed dough foods under heating and humidification, an agent for improving the texture of cooked dough foods, and an agent for improving the mechanical resistance of dough, and the production of dough using these, which contain branching enzyme as an active ingredient. The present invention relates to a method, a method for producing a dough cooked food, and a method for producing a dough steamed food.

Dough is a food dough made by mixing starch-based ingredients obtained from grains, beans, etc. with water and other ingredients (secondary ingredients) as needed, and the water content is compared. It refers to a hard material with little target and poor fluidity. Dough is used for food after being cooked by baking, steaming, frying, boiling, etc. Specific examples include skins such as bread, donuts, pies, noodles, and spring rolls, bun skins, dumplings, cookies, and rice cakes. The dough for baked confectionery can be mentioned. As mentioned above, the food products produced by heating these doughs have a wide range of products, and their market size is large, occupying an important position in the food industry.

Hereinafter, in the present invention, a food containing a step of heating the dough in the manufacturing process is referred to as a dough-heated food. Further, among the dough-heated foods, those in which the method of heating the dough is "steaming" are called dough-steamed foods.

Typical examples of steamed dough foods include Chinese steamed buns such as meat buns, steamed buns, and pizza buns, Japanese sweets buns such as sake buns and buns, steamed buns, and dim sum such as dumplings and shumai. Of these, Chinese steamed buns are sold as frozen foods and chilled products at supermarkets, etc., and are also widely deployed as products that are heated and sold at convenience stores and shops.

Here, in the case of heated sales at convenience stores and shops, cooked Chinese steamed buns are placed in a steamer called a steamer so that consumers can eat them immediately after purchase, and are sold in a constantly heated and humidified state. A mode to be used. In such a sales mode, the Chinese steamed bun stored for a long time with a steamer absorbs a large amount of water, and as a result, the skin becomes very soft and buyobuyo, and the texture is significantly deteriorated. In addition, this problem is also a factor in shortening the expiration date and causing disposal loss.

Therefore, Chinese steamed buns whose quality does not deteriorate even when stored for a long time with a steamer are being researched and developed. For example, Patent Document 1 discloses Chinese steamed buns containing ι carrageenan and organic acid monoglyceride, and the Chinese steamed buns maintain a good texture even after being stored for a long time under heating. It is stated that. Further, Patent Document 2 discloses a method for producing a Chinese manju food using a specific strain of Saccharomyces cerevisiae, and the Chinese manju food produced by this method can be used even after being re-steamed for a long time. It is described that browning and solidification of the epidermis are suppressed, the specific volume of the product is increased, and the soft texture is maintained.

JP-A-2017-70256 Japanese Patent No. 4156187

However, although there is a description in the sensory test that the Chinese steamed buns described in Patent Document 1 have a relatively small "sticky texture" after being stored at 65 to 75 ° C. for 5 hours, the amount of water absorption has been studied. Therefore, it is unclear whether the steamer has a sufficient texture-maintaining effect after long-term storage. The Chinese manju food produced by the method described in Patent Document 2 has not been examined at all regarding the amount of water absorption and texture after storage in a steamer. That is, even in view of these patent documents, a technique for producing a dough-steamed food that can suppress water absorption during storage under heating and humidification and maintain a good texture is not sufficiently provided.

In addition, the inner layer of dough-heated food usually exhibits traces of a large number of bubbles (sudachi, bubble structure) generated during fermentation and swelling. Aspects such as the size and amount of the hole-shaped bubble traces, the thickness and uniformity of the film constituting the bubbles are referred to as the texture of the inner layer. In general, fine texture means that the diameter of the holes in the sudachi is small, the number of holes is large, and the film constituting the holes is thin. In addition, high texture uniformity means that the diameters of many sudachi holes are small and are relatively the same size.

If the inner layer of the dough-heated food is rough and uneven, the appearance will be poor and the texture will be lacking in softness and melting in the mouth. Therefore, the present inventors can produce a dough-heated food having a good appearance, a softer texture, and a pleasant texture if the inner layer of the dough-heated food can be made finer or more uniform. We thought that it could contribute to the improvement of commercial value. In this respect, none of the prior arts described in the above patent documents solves the problem of making the texture of the dough-heated food finer or increasing the uniformity.

In addition, when the dough-heated food is manufactured using a machine, the dough may be damaged. This damage often occurs when the process of division and molding is handled by a machine. Damaged dough has poor swelling during the heating process, and the dough-heated food has insufficient volume and lacks soft texture. Therefore, if the mechanical resistance of the dough can be increased, the present inventors will be able to improve the commercial value, shift from manual to mechanized, increase the operating speed of the machine, etc., and reduce the production cost or productivity. I thought that it could contribute to the improvement of. In this respect, none of the prior arts described in the above patent documents solves the problem of improving the mechanical resistance of the dough.

The present invention has been made to solve such a problem, and is an agent capable of improving the storage resistance of a dough steamed food under heating and humidification, an agent capable of improving the texture of a dough cooked food, and a dough. It is an object of the present invention to provide an agent capable of improving mechanical resistance, and a method for producing dough and a method for producing food using the same.

As a result of diligent research, the present inventors have found that by adding a branching enzyme to the dough material, it is possible to suppress water absorption and softening that normally occur when the dough steamed food is stored in a heated and humidified state. It was found that the texture of the inner layer can be made finer and the uniformity can be improved, and that the damage to the dough that normally occurs when the dough manufacturing process is performed by a machine or the defect of swelling caused by the damage can be suppressed. Therefore, based on these findings, the following inventions have been completed.

(1) The storage resistance improving agent for the dough steamed food according to the present invention under heating and humidification contains a branched enzyme as an active ingredient.

(2) The texture improving agent for dough-heated foods according to the present invention contains a branching enzyme as an active ingredient.

(3) The mechanical resistance improving agent for dough according to the present invention contains a branched enzyme as an active ingredient.

(4) In the agent according to the present invention, the branching enzyme can be a polypeptide having the following amino acid sequence (a) or (b) and having branching enzyme activity;
(A) Amino acid sequence having 90% or more sequence identity with SEQ ID NO: 2.
(B) An amino acid sequence encoded by any of the following nucleic acid sequences (a) to (c),
(A) Nucleic acid sequence of SEQ ID NO: 1,
(A) Nucleic acid sequence complementary to SEQ ID NO: 1,
(C) A nucleic acid sequence that hybridizes with (a) or (b) under stringent conditions.

(5) The method for producing dough according to the present invention includes a step of mixing the agent according to the present invention with the material constituting the dough.

(6) The method for producing a dough-heated food according to the present invention includes a step of heating the dough containing the agent according to the present invention.

(7) The method for producing a dough steamed food according to the present invention includes a step of steaming the dough containing the agent according to the present invention.

According to the storage resistance improving agent for dough steamed foods according to the present invention under heating and humidification, the method for producing dough using the same, or the method for producing dough steamed foods, when the dough steamed foods are stored in a heating and humidifying environment. It is possible to suppress water absorption and softening that normally occur in Japan. Therefore, even when the product is sold in a heated and humidified state, the original good texture of the product can be maintained for a long time, thereby improving the commercial value of the product, extending the expiration date, and reducing waste loss. Can contribute.

According to the texture improving agent for dough-heated foods according to the present invention, the method for producing dough using the same, or the method for producing dough-heated foods, the texture of the inner layer of the dough-heated foods can be made finer or more uniform. Therefore, it can contribute to the improvement of commercial value in the production of dough or foods using the dough.

According to the dough machine resistance improver according to the present invention, the dough manufacturing method using the dough manufacturing method, or the dough heated food manufacturing method, the dough is usually damaged or swelled when the dough manufacturing process is performed by a machine. Defects can be suppressed. Therefore, it is possible to contribute to the reduction of production cost and the improvement of productivity by improving the commercial value, shifting from manual to mechanization, increasing the operating speed of the machine, and the like.

It is a bar graph which shows the maximum load when crumbs were compressed before and after storage in a steamer for Chinese steamed buns without branching enzyme (Sample 1) and Chinese steamed buns with branching enzyme (Sample 2). It is an observation image by the electron microscope of the inner layer of the Chinese steamed bun (Sample 1) to which branching enzyme was not added, and Chinese steamed bun (Sample 2) to which branching enzyme was added. It is a bar graph which shows the volume of the Chinese steamed bun (Sample 1) which did not add a branching enzyme, and the Chinese steamed bun (Sample 2) which added a branched enzyme.

Hereinafter, the present invention will be described in detail. The agent for improving the storage resistance of steamed dough foods according to the present invention under heating and humidification, the agent for improving the texture of cooked dough foods, and the agent for improving the mechanical resistance of dough (hereinafter, may be collectively referred to as "the agent of the present invention". ) Have a branched enzyme as an active ingredient. Further, the method for producing a dough according to the present invention includes a step of mixing the agent of the present invention with the material constituting the dough. In addition, the method for producing a dough-heated food according to the present invention includes a step of heating the dough containing the agent of the present invention. In addition, the method for producing a dough steamed food according to the present invention includes a step of steaming the dough containing the agent of the present invention.

"Preservation resistance under heating and humidification" means that water absorption and softening that normally occur when dough steamed foods are stored in a heating and humidifying environment are unlikely to occur, or even if they do occur, the degree is small. .. That is, when this storage resistance is high, the amount of water absorbed by the dough steamed food when stored under heating and humidification is small, or the degree of softening is small, and as a result, a good texture is maintained. It can be said that the time will be longer.

Here, the temperature in the case of "preserving the dough steamed food under heating and humidification" may be heated so as to exceed the outside air temperature or room temperature, and is not particularly limited. Examples of the temperature inside the container for storing the dough steamed food include room temperature and above and below 100 ° C., below 50 to 100 ° C., below 60 to 100 ° C., and below 60 to 90 ° C. Further, the humidity in this case is not particularly limited as long as the inside of the container for storing the dough steamed food is humidified, but specifically, 90 to 100% can be exemplified.

In the present invention, "improving the texture" of the dough-heated food means making the inner layer of the dough-heated food finer and / or enhancing the texture uniformity.

In the present invention, "mechanical resistance of dough" means that when a dough-heated food manufacturing process such as division or molding is performed using a machine, the dough is usually damaged or a defect in swelling due to the damage occurs. It means that it is difficult, or even if it occurs, the degree is small.

A branching enzyme (branching enzyme, EC 2.4.1.18) is a transferase (6-α-glucanotransferase) that acts on glucose-constituting polysaccharides such as starch and glycogen. This enzyme cleaves the α-1,4 bond and catalyzes the reaction of transferring to another location with the α-1,6 bond. As used herein, a branched enzyme may be simply referred to as an "enzyme".

In the present invention, the branching enzyme activity is described by Takata et al. , Applied and Environmental Microbiology (1994), p. It can be confirmed according to the improved version of the method described in 3097 (assayA). Specifically, first, 50 μL of an enzyme solution and 50 μL of a substrate solution (a 0.1 M Tris buffer solution in which type III amylose is dissolved at a concentration of 0.1%) are mixed, and 30 at 60 ° C. Incubate for minutes. Subsequently, 2 mL of iodine reagent is mixed and incubated at room temperature for 15 minutes to form an amylose-iodine complex. The iodine reagent is prepared by mixing 0.5 mL of 1N HCl with 0.5 mL of a preservative solution (0.26 g of I ₂ and 2.6 g of KI dissolved in 10 mL of water), and then watering the mixture to make 130 mL. Diluted with. Then, the absorbance (A ₆₆₀ ) at ₆₆₀ nm is measured. The control sample used is an enzyme solution replaced with water. Branching enzyme activity is measured as the difference in A ₆₆₀ between the test sample and the control sample. The branching enzyme activity of one unit (U) is defined as the amount of enzyme capable of lowering A ₆₆₀ by 1% per minute at 60 ° C. and pH 7.0.

The branching enzyme has an optimum temperature in the range of 60 ° C. to 120 ° C., preferably 60 ° C. to 100 ° C., more preferably 60 ° C. to 80 ° C., and even more preferably 60 ° C. to 70 ° C. Further, those having an optimum pH (relative activity of 70% or more) in the range of 6 to 8 are preferable.

As the transferase, a commercially available transferase preparation for food can be used, and examples of such a commercially available product include "Branchzyme" (Novozymes) and "Denateam BBR LIGHT" (Nagase Chemtex). , Glycotransferase "Amano" L (Amano Enzyme) and the like.

Further, as the branching enzyme, one extracted and purified from naturally occurring organisms such as plants and microorganisms according to a conventional method may be used. Organisms with branching enzymes include, for example, Rhodothermus obamensis, Rhodothermus marinus, Arthrobacter globiformis, Bacillus megaterium, Streptococcus mic , Salmonella typhimurium, algae Cyanidium caldarium, Escherichia coli, Bacillus caldolyticus, Geobacillus stearothermophilus, Synecococcus, etc. it can.

Methods for preparing a branching enzyme from a naturally occurring organism include, for example, a step of culturing a microorganism that produces the branching enzyme (culture step), a step of separating microbial cells from a culture solution (bacterial cell separation step), and a step. Including a step of extracting and purifying a branched enzyme from microbial cells (extraction purification step). In the culturing step, the microorganism is cultured in a medium containing a nutrient source that can be used by the microorganism. The form of the medium may be liquid or solid as long as it promotes the production of branched enzymes, but it is liquid in that the medium can be easily prepared and cultured to a high bacterial concentration. Medium is preferred. Nutrient sources include, for example, carbon sources, nitrogen sources and inorganic salts. Carbon sources include, for example, glucose, glycerin, dextrin, starch, molasses, and animal and vegetable oils. Nitrogen sources include, for example, soybean flour, corn steep liquor, cotton dregs, meat extract, peptone, yeast extract, ammonium sulfate, sodium nitrate, and urea. Inorganic salts include, for example, sodium, potassium, calcium, magnesium, manganese, iron, cobalt, zinc, and phosphoric acid. The culturing method may be static culture, shaking culture, or aeration stirring culture, but aeration stirring culture is preferable from the viewpoint that air and nutrient sources can be efficiently supplied to the cells. The culture temperature can be, for example, 25 ° C to 70 ° C, preferably 30 ° C to 60 ° C. The pH of the medium can be pH 5 to pH 8. The culturing time is, for example, 1 to 7 days, and the culturing is stopped when the intracellular accumulation amount of the branching enzyme becomes maximum. The cell separation step can be performed, for example, by centrifugation, filtration, or vacuum distillation. Extraction methods in the extraction and purification steps include, for example, physical methods such as freeze-thaw, high-pressure homogenizer treatment, and bead treatment, treatment with chemicals that damage cell membranes, methods of rapidly changing osmotic pressure, alkali treatment, and enzyme treatment. Such chemical methods can be mentioned. The purification method in the extraction and purification step is for branching by a known means such as ultrafiltration using a filtration membrane having an exclusion molecular weight of 5000 or an exclusion molecular weight of 10000, fractionation using ammonium sulfate or ethanol, and purification by chromatography. It can be used in combination as appropriate depending on the degree of purification of the enzyme. As the branching enzyme, a solution containing the branching enzyme may be used as it is in a liquid state, or may be used as a powdered enzyme obtained by vacuum drying or freeze-drying.

As a branching enzyme preferably used in the present invention, a polypeptide having the following amino acid sequence (a) or (b) (hereinafter, may be referred to as “the present polypeptide”) can be exemplified;
(A) Amino acid sequence having 90% or more sequence identity with SEQ ID NO: 2.
(B) An amino acid sequence encoded by any of the following nucleic acid sequences (a) to (c),
(A) Nucleic acid sequence of SEQ ID NO: 1,
(A) Nucleic acid sequence complementary to SEQ ID NO: 1 (SEQ ID NO: 3),
(C) A nucleic acid sequence that hybridizes with (a) or (b) under stringent conditions.

Here, SEQ ID NO: 2 is equivalent to the amino acid sequence of SEQ ID NO: 2 described in Japanese Patent No. 4732591, and SEQ ID NO: 1 is equivalent to the nucleic acid sequence of SEQ ID NO: 1 described in the same publication. SEQ ID NO: 2 is the amino acid sequence of the branching enzyme of the Rhodotherms obamensis strain JCM 9785 (hereinafter, may be referred to as "JCM9785 branching enzyme"). Further, SEQ ID NO: 1 is a nucleic acid sequence encoding the amino acid sequence of SEQ ID NO: 2. Moreover, SEQ ID NO: 3 is a nucleic acid sequence complementary to SEQ ID NO: 1. That is, this polypeptide means a branching enzyme having the same or high similarity to JCM9785 branching enzyme in terms of amino acid sequence and enzyme activity.

This polypeptide can be obtained by extraction and production from the Rhodotherms obamensis strain JCM 9785 (RIKEN Microbial Strain Preservation Facility) by the above method. Further, based on the amino acid sequence information of (a) or (b) described above, chemical synthesis is performed according to a chemical synthesis method such as the Fmoc method (fluorenylmethyloxycarbonyl method) or the tBoc method (t-butyloxycarbonyl method). In addition to this, it can also be chemically synthesized using various commercially available peptide synthesizers.

The present polypeptide can also be obtained by gene recombination technology. In this method, the present polypeptide may be expressed in a suitable expression system. That is, the nucleic acid sequences (a) to (c) are inserted into an appropriate vector to obtain a recombinant vector, and then the recombinant vector is introduced into an appropriate host to obtain a transformant. Then, it can be obtained by culturing the obtained transformant to express the present polypeptide. Here, the nucleic acid sequences (a) to (c) can be synthesized using various commercially available DNA synthesizers based on the sequence information, and DNA encoding the JCM9785 branching enzyme can be used. It can be obtained by performing a polymerase chain reaction (PCR) as a template. Further, as the transformant, a clone of Escherichia coli (NMO049443, deposit number DSM12607) described in Japanese Patent No. 4732591 (paragraph [0207], etc.) can also be used.

The identity of the amino acid sequence can be confirmed according to a conventional method. For example, FASTA (http://www.genome.JP/tools/fasta/), National center for biotechnology information (BLAST; http: //). It can be confirmed by using a program such as www.ncbi.nlm.nih.gov.), Position-Specificidicated BLAST (PSI-BLAST; http: // www.ncbi.nlm.nih.gov.). In addition, "identity" refers to consistency and is used interchangeably with "identity".

Hybridization under stringent conditions can be exemplified by: 5 × SSPE, 0.3% SDS, 200 μg / ml sheared and denatured salmon sperm DNA, standard Southern in 50% formamide. Prehybridization and hybridization at 42 ° C. according to the blotting method. Washed 3 times at 65 ° C. or 70 ° C. for 15 minutes each using 2 × SSC, 0.2% SDS.

In the present invention, the branching enzyme is used by mixing it with the material constituting the dough. As the timing of adding the branching enzyme, a step of mixing various materials constituting the dough can be exemplified. The amount of the branching enzyme added is not particularly limited, and examples thereof include 25 to 125,000 U, 125 to 25,000 U, and 250 to 2500 U per kg of wheat flour.

In the present invention, the main ingredients for composing dough are foodstuffs mainly composed of starch such as water and flour (wheat flour, rice flour, barley flour, rye flour, corn flour, potato flour, tef flour, hie flour, and kin flour. , Soybean flour, chick soybean flour, pea flour, green bean flour, buckwheat flour, amaranthus flour, kataguri flour, waste flour, tapioca flour, chestnut flour, acorn flour, etc.). In addition, any auxiliary material other than the above can be blended in the dough, and such auxiliary materials include, for example, yeast, fats and oils, seasonings such as sweeteners and salt, dairy products, eggs, and gluten. Various food additives, dough improvers, leavening agents and the like can be mentioned.

As described above, the dough-heated food refers to a food that includes a step of heating the dough in its manufacturing process. In the present invention, the heating method for producing a dough-heated food is not particularly limited, and for example, the dough is heated by any method such as baking (baking), steaming (steaming), frying (oil-like), and boiling. Can be done.

As described above, the dough steamed food refers to a dough-heated food whose method of heating the dough is a "steaming" method. That is, a dough steamed food is a food that includes a step of steaming dough in its manufacturing process. In the present invention, the dough steamed food may be wrapped with ingredients or bean paste inside, such as Chinese steamed buns or Japanese sweets buns, or may be a steamed bread or mantou, which does not contain anything inside. In addition, "steaming" means heating the material with the heat of steam generated by boiling water.

Hereinafter, the present invention will be described based on each example, but the technical scope of the present invention is not limited to the features shown by these examples. In this example, the branching enzyme used was a polypeptide consisting of an amino acid sequence having 90% or more sequence identity with SEQ ID NO: 2.

<Example 1> Verification of effect of branching enzyme: Water absorption after storage under heating and humidification (1) Production of Chinese steamed buns Chinese steamed buns of Sample 1 and Sample 2 are produced according to the formulation shown in Table 1 and stored frozen. did. The specific procedure is shown in [1] to [8] below. In addition, since the purpose of this embodiment was mainly to evaluate the portion (skin portion) formed by heating the dough, a Chinese steamed bun containing no ingredients was produced.

<< Manufacturing procedure of Chinese steamed bun >>
[1] Kneading: The materials shown in Table 1 were placed in a mixer (Aikosha Seisakusho) and kneaded at a low speed for 3 minutes and then at a medium speed for 5 minutes to prepare a dough.
[2] Molding: The dough was manually divided into 30 g / piece and molded into a round shape.
[3] Fermentation: The molded dough was fermented by leaving it at 40 ° C. and 70% humidity for 60 minutes.
[4] Rack time: The fermented dough was left at room temperature for 10 minutes to dry the surface.
[5] Steaming: A Chinese steamed bun was prepared by steam heating at 100 ° C. for 20 minutes in a steamer.
[6] Cooling: The heated Chinese steamed bun was cooled by leaving it at room temperature for 15 minutes.
[7] Quick freezing: Quick freezing was performed by placing the product in a quick freezer at −40 ° C. for 60 minutes.
[8] Freezing storage: Freezing storage in a freezer at −20 ° C.

(2) Evaluation of water absorption After thawing the Chinese steamed buns of Sample 1 and Sample 2 at room temperature for 30 minutes, the weight was measured, and this was defined as the "weight before steaming and storage". Subsequently, it was stored for 6 hours in a steamer at 80 ° C. to 90 ° C. and 100% humidity. Then, the weight was measured, and this was defined as "weight after steaming and storage". The water absorption amount and the water absorption rate were calculated by the following formulas 1 and 2. The results are shown in Table 2. In Table 2, each numerical value is an average value of 5 Chinese steamed buns in each sample.
Equation 1: Water absorption (g) = Weight after steaming storage (g) -Weight before steaming storage (g)
Equation 2: Water absorption rate (%) = (water absorption amount (g) ÷ weight after steaming and storage (g)) x 100

As shown in Table 2, the amount of water absorption was 3.20 g in Sample 1 and 1.40 g in Sample 2. The water absorption rate was 10.46% in sample 1 and 4.60% in sample 2. That is, the amount of water absorbed by the skin of the Chinese steamed bun was significantly smaller when the branching enzyme was added than when the branching enzyme was not added. From this result, it was clarified that the branching enzyme can suppress water absorption when the dough steamed food is stored in a heated and humidified state.

<Example 2> Verification of effect of branching enzyme: Softening by storage under heating and humidification Chinese steamed buns were produced by the method described in Example 1 (1) and stored frozen. Subsequently, the Chinese steamed bun was left at room temperature for 30 minutes to thaw, and then a rectangular parallelepiped of 3 cm × 3 cm × 2.5 cm square was cut out from the inner layer. Using a cylindrical plunger with a diameter of 5 cm of a creep meter (Sanden), the rectangular parallelepiped was compressed at a compression rate of 1 mm / sec until it was compressed and deformed by 60% by volume, and the maximum load at that time was measured. Further, after storing for 6 hours in a steamer at 80 ° C. to 90 ° C. and 100% humidity, a rectangular parallelepiped was cut out in the same manner and the maximum load was measured. The result is shown in FIG. In FIG. 1, the numerical value at the upper part of the bar graph is the average value of 5 Chinese steamed buns in each sample.

As shown in FIG. 1, in Sample 1, the maximum load before storage in the steamer (before steam storage) was 11.38 N, and the maximum load after storage (after steam storage) was 8.78 N. On the other hand, in Sample 2, the maximum load before steaming and storage was 10.44N, and the maximum load after steaming and storage was 9.74N. That is, the maximum load of sample 2 after steaming and storage was remarkably larger than that of sample 1, and the amount of change in maximum load before and after storage was also small. From this result, it was clarified that the softening of the skin of the dough steamed food due to long-term storage under the warming and humidifying condition can be suppressed when the branching enzyme is added than when the branching enzyme is not added. .. That is, it was clarified that the branching enzyme is effective in maintaining the texture when the dough steamed food is stored under heating and humidification.

<Example 3> Verification of effect of branching enzyme: Texture of inner layer Chinese steamed buns were produced by the method described in Example 1 (1) and stored frozen. However, in the molding step of [2], the amount of dough was set to 60 g / piece, and a packing machine (CN600, Leon automatic machine) was used instead of manual operation. Subsequently, the frozen Chinese steamed bun was sliced to a thickness of 10 mm into fragments, and freeze-dried overnight using a freeze dryer (FD-1000, EYELA). Then, the surface of the fragment is vapor-deposited with gold using a magnetron ion coater (MSP-1S, Vacuum Device Co., Ltd.), and the observation magnification is 30 times or 50 times using a scanning electron microscope (VHX-D510, manufactured by KEYENCE). Observed. The observation image is shown in FIG.

As shown in FIG. 2, in the inner layer of the sample 2, the diameter of each hole of the sudachi (bubble structure) was smaller, the number of holes was larger, and the film forming the holes was thinner than that of the sample 1. Further, the sample 2 had a smaller variation in the hole size than the sample 1, and the holes had a relatively same size. That is, the texture of the inner layer was finer and more uniform when the branching enzyme was added than when the branching enzyme was not added. From this result, it was clarified that the branching enzyme makes the texture of the inner layer of the dough-heated food finer and enhances the uniformity.

<Example 4> Verification of effect of branched enzyme: Mechanical resistance Chinese steamed buns were produced by the method described in Example 1 (1) and stored frozen. However, in the molding step of [2], the amount of dough was set to 60 g / piece, and a packing machine (CN600, Leon automatic machine) was used instead of manual operation. The rotation speed of the agitator (rotary nozzle) of the packing machine was set to the highest speed 6. The higher the rotation speed of the agitator, the greater the load on the dough. Subsequently, the Chinese steamed bun was allowed to thaw at 25 ° C. for 1 hour, and then the volume and weight were measured to calculate the volume (specific volume) per gram. The results are shown in Table 3. A bar graph of volume is shown in FIG. In Table 3 and FIG. 3, each numerical value is an average value of 15 Chinese steamed buns in Sample 1 and 22 Chinese steamed buns in Sample 2.

As shown in Table 3, the weight of sample 1 was 50.9 g and that of sample 2 was 50.2 g, both of which were equivalent. On the other hand, as shown in Table 3 and Figure 3, volume, whereas it was in Sample 1 180.6Cm ^3, a Sample 2 194.8Cm ^3, significantly greater in the sample 2 It was. The specific volume of sample 1 was 3.22 cm ³ / g, whereas that of sample 2 was 3.88 cm ³ / g. That is, although the weights of both were the same, the volume was larger when the branching enzyme was added than when the branching enzyme was not added, so that the swelling caused by the damage of the dough due to the mechanical load was caused. It was revealed that the defect was reduced by the branching enzyme. From this result, it was clarified that the branching enzyme improves the mechanical resistance of the dough in the dough-heated food.

Claims (7)

An agent for improving storage resistance of steamed dough foods under heating and humidification, which contains a branching enzyme as an active ingredient. A texture improver for dough-heated foods containing a branching enzyme as an active ingredient. A dough machine resistance improver containing a branching enzyme as an active ingredient. The agent according to any one of claims 1 to 3, wherein the branching enzyme is a polypeptide having the following amino acid sequence (a) or (b) and having branching enzyme activity;
(A) Amino acid sequence having 90% or more sequence identity with SEQ ID NO: 2.
(B) An amino acid sequence encoded by any of the following nucleic acid sequences (a) to (c),
(A) Nucleic acid sequence of SEQ ID NO: 1,
(A) Nucleic acid sequence complementary to SEQ ID NO: 1,
(C) A nucleic acid sequence that hybridizes with (a) or (b) under stringent conditions. A method for producing dough, which comprises a step of mixing the agent according to any one of claims 1 to 4 with a material constituting the dough. A method for producing a dough-heated food, which comprises a step of heating the dough containing the agent according to any one of claims 1 to 4. A method for producing a dough steamed food, which comprises a step of steaming a dough containing the agent according to any one of claims 1 to 4.