Method for producing protein-enriched breads

Abstract

The purpose of the present invention is to provide breads which are capable of maintaining sufficient dough rising properties and texture without inhibiting the gluten network of the breads even when a comparatively large amount of powdered soybean protein is included therein.　A method for producing protein-enriched breads which contain plant protein in the amount of 5-20 wt% relative to grain flour, said method being characterized in that a powdered plant protein ingredient which satisfies specific requirements is added to the bread dough as a source of plant protein.

Description

[Technical Field]

[0001] The present invention relates to a method for producing protein-enriched breads. [Background technology]

[0002] Proteins are polymers with amphiphilic properties, which allow them to gel, thicken, and retain water. Powdered vegetable protein products, such as soy protein isolate (SPI), which contains high concentrations of protein, are easier to distribute and store than liquid products because they do not contain water. Furthermore, these products can be incorporated into processed foods at high concentrations, making them widely used as additives to improve the physical properties of various processed foods. For example, soy protein has a well-balanced amino acid composition and physiological functions such as lowering serum cholesterol, so it is used in nutritional and health-promoting foods that are expected to provide nutritional and physiological functions.

[0003] According to the 2011 White Paper on Aging Society published by Japan's Cabinet Office, the population of people aged 65 and over will reach a record high of 29.58 million, meaning that one in five people will be elderly. This means that a super-aged society (a society in which people aged 65 and over account for more than 21% of the total population) is fast approaching. In light of this, one of the goals set out in the "Healthy Japan 21" initiative promoted by Japan's Ministry of Health, Labor and Welfare is to extend healthy lifespan. "Healthy lifespan" here refers to the period of time spent free from illness or disability, and is calculated as follows: healthy lifespan (average period of independence) = average lifespan - period of non-independence (period of time during which one's health deteriorates and one is unable to live independently).

[0004] In order to extend healthy lifespan, it is essential to consume the necessary amount of nutrients. Protein, in particular, is an essential substance for maintaining life, building tissues and fulfilling various functions. According to the "Dietary Reference Intakes for Japanese" (2010 edition) published by the Ministry of Health, Labor and Welfare, the recommended protein intake for elderly people aged 70 years and older is 60g per day, the same as that of the general adult. However, elderly people generally have less active daily activities. As a result, their appetite decreases and their food intake decreases. Therefore, elderly people need to efficiently ingest protein in small amounts.

[0005] Under these circumstances, food manufacturers are focusing on developing processed foods that utilize the excellent nutritional physiological functions of vegetable proteins and aim to replenish vegetable proteins. One such processed food category is protein-enriched bread. Here, a powdered vegetable protein material such as isolated soy protein has a high protein content and is therefore suitable for the purpose of increasing the protein content of breads. Furthermore, because this material is in powder form, it has the advantage of being able to be handled in the same way as wheat flour. Furthermore, because this material does not contain a large amount of water like soy milk, the amount of this material added to breads for protein enrichment is also advantageous in that it is not limited by the moisture content allowed in bread dough.

[0006] However, when a large amount of vegetable protein such as soy protein is added to bread dough in order to enhance the protein content, the vegetable protein absorbs moisture from the dough due to its water-retaining properties and also inhibits the gluten network of wheat flour. Therefore, breads containing a large amount of vegetable protein tend to have a small specific volume and a poor texture. Therefore, it has been difficult to obtain high-protein breads with sufficient specific volume and a soft texture.

[0007] Therefore, there is a need to provide a technology that will prevent a decrease in the specific volume of breads or a deterioration in texture even when a relatively large amount of vegetable protein is blended into breads. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 11-243844 [Patent Document 2] International Publication No. WO2007 / 114129 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-142200 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-2059

[0009] Patent Document 1 describes a method for producing protein-enriched breads, which is characterized by adding powdered soy protein and xylanase to bread dough. It is stated that this technology contributes to preventing a decrease in the specific volume of protein-enriched breads.

[0010] Patent Document 2 describes a powdered soy protein material that contains magnesium salts such as magnesium oxide and is partially hydrolyzed with a protease. Examples of this powdered soy protein material include one with an NSI of 32 and a 0.22M TCA solubility of 11%, one with an NSI of 17 and a TCA solubility of 10%, one with an NSI of 45 and a TCA solubility of 10%, and one with an NSI of 30 and a TCA solubility of 22%. It is described that this technology is effective for producing baked foods such as protein-enriched cookies.

[0011] The examples in Patent Document 3 describe the blending of soybean puffs (protein content 78% by weight) and powdered soy protein material into baked confectionery dough. The soybean puffs are structured using an extruder, and this technology is characterized by its use.

[0012] Patent Document 4 describes a soy protein ingredient for protein enrichment of breads, which is prepared by forming a paste containing 10 to 50% by weight of a powdered soy protein ingredient, drying this with hot air at 100 to 250°C to a moisture content of 15% by weight or less, and then powdering it again.The patent document also describes that producing breads using this ingredient contributes to preventing a decrease in the specific volume of protein-enriched breads. Summary of the Invention [Problem to be solved by the invention]

[0013] When attempting to enrich bread with protein or reduce the sugar content by adding a powdered vegetable protein material to bread, it remains difficult to obtain the rise and texture suitable for bread. Therefore, an object of the present invention is to provide breads that can maintain sufficient dough rise and texture without inhibiting the gluten network of the breads, even when a relatively large amount of powdered soy protein is blended. [Means for solving the problem]

[0014] As a result of extensive research, the inventors discovered a powdered vegetable protein material with specific properties, and discovered that by adding this material as an ingredient in breads, the above-mentioned problems could be solved, leading to the completion of the present invention.

[0015] That is, the present invention includes the following configurations. (1) Bread containing 5 to 20% by weight of vegetable protein based on flour, A powdered vegetable protein material that satisfies at least the following requirements A) to C) is added to bread dough as a vegetable protein source: Method for producing protein-enriched breads, A) The protein content in the solid content is 80% by weight or more, B) The pH of a 10% by weight solution is pH 6 to 8. C) Nitrogen Solubility Index (NSI) of 30 or less; D) The solubility in 0.22M trichloroacetic acid is less than 10%. E) containing water-soluble bean polysaccharides, or alginic acid or a salt thereof; (2) The method for producing breads according to (1) above, wherein the powdered vegetable protein material is selected from soybeans, peas, and mung beans. (3) The method for producing breads according to (1) or (2), wherein the protein content in the solid content of the powdered vegetable protein material is 85% by weight or more. (4) The method for producing breads according to any one of (1) to (3) above, wherein the pH of a 10 wt % solution of the powdered vegetable protein material is 6.7 to 7.3. (5) The method for producing breads according to any one of (1) to (4) above, wherein the nitrogen solubility index (NSI) of the powdered vegetable protein material is 25 or less. (6) The bread according to any one of (1) to (5), wherein the calcium content in the solid content of the powdered vegetable protein material is 0.5% by weight or less and the magnesium content is 0.25% by weight or less. (7) The bread according to any one of (1) to (6), wherein the solubility of the powdered vegetable protein material in 0.22 M trichloroacetic acid is 5% or less. (8) The bread according to any one of (1) to (7), wherein the polysaccharide contained in the powdered vegetable protein material is a water-soluble bean polysaccharide. (9) Breads according to (8) above, wherein the water-soluble bean polysaccharide is a water-soluble soybean polysaccharide or a water-soluble pea polysaccharide. [Effects of the Invention]

[0016] According to the present invention, a relatively large amount of powdered vegetable protein material is blended, and breads having a texture and shape similar to conventional breads can be obtained despite being high in protein. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described in detail.

[0018] (Bread) In the present invention, "breads" refers to, for example, white bread, roll bread, Danish pastry, French bread, ciabatta, focaccia, naan, pizza, bagels, English muffins, pies, sweet rolls, yeast donuts, etc., but is not limited to these names and includes all types generally recognized as bread and its related products. Breads may be produced in accordance with conventional methods, and generally, dough is prepared by kneading ingredients whose main components are wheat flour, whole wheat flour, rice flour, or other grain flour, water, yeast, sugars, salt, fats and oils, and the like, and then shaping the dough into a desired shape, followed by baking in an oven or frying. When preparing bread dough, the order in which the above ingredients are added can be either a method in which all ingredients are mixed together (straight method), in which the dough is prepared, or a method such as the sponge method or the tangzhan method, in which a starter dough is prepared first using some of the ingredients, and then the remaining ingredients are added to prepare the main dough. In the present invention, the effect is particularly pronounced in breads which are made by forming a gluten network in the dough and then undergoing a leavening process with yeast. In this specification, breads obtained by the production method of the present invention may be referred to as "breads of the present invention."

[0019] (vegetable protein) The present breads contain at least 5 to 20% by weight of vegetable protein as a nutritional component relative to the flour. A higher protein content is preferable, as this effectively demonstrates the effects of the present invention, and 10% by weight or more is preferred. Vegetable protein tends to inhibit the gluten network in bread dough, resulting in a decrease in specific volume and a deterioration in texture. These phenomena significantly impair the commercial value of breads. On the other hand, the present invention solves these problems even when the bread contains a high amount of vegetable protein.

[0020] Examples of types of vegetable proteins include proteins derived from beans such as soybeans, peas, mung beans, chickpeas, and cowpeas, as well as canola seeds.

[0021] (Powdered vegetable protein material) The protein in the present breads is contained in whole or in part as a result of adding the above-mentioned vegetable protein-containing protein material to the present breads. Here, in the method for producing the present breads, one essential and important protein material is a specific "powdered vegetable protein material" described in detail below. The term "powdered vegetable protein material" used herein refers to a food material that is in the form of a powdered product and is primarily made of protein derived from plants. As a typical example, when the plant is soybean, defatted soybean flakes are used as the soybean raw material, and these are dispersed in an appropriate amount of water to carry out water extraction, followed by removal of the insoluble fraction mainly composed of fiber to obtain an extracted soy protein (defatted soy milk). Furthermore, the extracted soy protein is adjusted to about pH 4.5 with an acid such as hydrochloric acid, the protein is isoelectrically precipitated to remove the acid-soluble fraction (whey), the acid-insoluble fraction (curd) is dispersed again in an appropriate amount of water to obtain a curd slurry, which is then neutralized with an alkali such as sodium hydroxide to obtain a neutralized slurry. The isolated soy protein obtained from the neutralized slurry is also included in the powdered soy protein material when it is made into a commercial product. The final product as a powdered soy protein material is produced by heat-sterilizing a solution of the extracted soy protein or isolated soy protein in a high-temperature heat treatment device, and then spray-drying the sterilized solution using a spray dryer, etc. That is, the most typical powdered vegetable protein material is a spray-dried powder of extracted protein or isolated protein. However, the production method is not limited to the above, and any method that can increase the purity of soy protein from soybean raw materials will do. Concentrated soy protein obtained by removing whey from defatted soybeans with ethanol or acid is also included in powdered soy protein materials. Of these, isolated soy protein is more commonly used than extracted soy protein because it typically has a high protein content of about 90% by weight of the solids.

[0022] (Characteristics of powdered vegetable protein) It is essential that the specific powdered protein ingredient used in the present breads itself meets at least the following requirements A) to E). In this specification, the powdered vegetable protein ingredient added to the present breads is sometimes referred to as the "present powdered vegetable protein ingredient." By kneading this present powdered vegetable protein ingredient into bread dough, it is possible to obtain high-quality breads that, despite being high in protein, have reduced volume loss and texture deterioration compared to ordinary breads. These requirements will be explained in more detail below.

[0023] A) Protein content in solids The powdered vegetable protein material suitably has a protein content of at least 80% by weight, preferably 85% by weight or more or 90% by weight or more, based on the solid content. A higher protein content is preferable because a smaller amount of the material can be added to produce high-protein, and incidentally low-carbohydrate breads. On the other hand, in order to increase the protein content of this powdered vegetable protein material, it is preferable that the insoluble dietary fiber content be as low as possible, and more preferably 2% by weight or less, 1% by weight or less, or 0.5% by weight or less on a dry basis. The insoluble dietary fiber content is measured by the modified Prosky method in accordance with the "Analysis Manual for the Standard Tables of Food Composition in Japan, 5th Edition" (document of the Food Composition Committee, Resources Survey Committee, Science and Technology Agency, 1997).

[0024] B) 10% by weight solution pH It is important that the present powdered vegetable protein material has a pH in the range of 6 to 8, preferably 6.5 to 7.5, and more preferably 6.7 to 7.3. If the powdered vegetable protein material is prepared to have too high a pH, it will be difficult to achieve the NSI of requirement C) below 30 or less. On the other hand, if the powdered vegetable protein material is prepared to have too low a pH, the flavor of breads will tend to deteriorate, which is undesirable.

[0025] C) Nitrogen Solubility Index (NSI) It is important that the present powdered vegetable protein material has an NSI (Nitrogen Solubility Index) of 30 or less as an index of solubility in water. In other words, it is important that the solubility in water is low. In a more preferred embodiment, the NSI may be 25 or less, 22 or less, or 20 or less. The NSI is expressed as the ratio (wt%) of water-soluble nitrogen (crude protein) to the total nitrogen amount based on a predetermined method, and in the present invention, it is a value measured in accordance with the method described below. If the NSI is too high, the powdered vegetable protein material will have high water retention properties, and when added to bread dough, the extensibility and rise of the dough will be impaired.

[0026] During the production of this powdered vegetable protein material, the NSI can be reduced by adding a divalent metal salt such as a calcium salt or magnesium salt to react the protein with the divalent metal. However, adding a large amount of calcium salt or magnesium salt to this powdered vegetable protein material makes it difficult to obtain a powdered vegetable protein material that does not affect gluten formation in bread dough, and therefore, it may be difficult to prepare bread dough of the desired quality.

[0027] Therefore, in one preferred embodiment, the calcium content of the solid content of the present powdered vegetable protein material may be 0.5 wt% or less, and the magnesium content may be 0.25 wt% or less. The calcium content may further be 0.4 wt% or less, 0.3 wt% or less, or 0.2 wt% or less. The magnesium content may further be 0.2 wt% or less, 0.15 wt% or less, or 0.1 wt% or less. Furthermore, the present powdered vegetable protein material may be one to which calcium salts and / or magnesium salts have not been added during production. The calcium and magnesium contents are measured by official atomic absorption spectrometry.

[0028] D) 0.22M trichloroacetic acid soluble fraction This powdered vegetable protein material is characterized by the absence of enzymatic degradation by proteases. The 0.22 M trichloroacetic acid solubility (hereinafter referred to as "TCA solubility") can be used as an indicator of the absence of enzymatic degradation. This value was determined by dispersing the powdered vegetable protein material in water to a protein content of 1.0 wt. % and thoroughly stirring the resulting dispersion, and measuring the proportion of protein soluble in 0.22 M trichloroacetic acid relative to the total protein using the Kjeldahl method. The TCA solubility value increases as protein hydrolysis progresses. The present powdered vegetable protein material is characterized by a TCA solubility rate of less than 10%. In some embodiments, the upper limit of the TCA solubility rate can be 7% or less, 6% or less, or 5% or less. Breads produced using the present powdered vegetable protein material having a TCA solubility rate within this range can be imparted with desirable specific volume and texture. A powdered vegetable protein material with a high TCA solubility rate, i.e., an enzymatically decomposed powdered vegetable protein material, is not preferred in the production of the present breads because it negatively affects the specific volume of the breads to which it is added.

[0029] E) Water-soluble polysaccharide content The present powdered plant protein material is characterized by containing specific water-soluble polysaccharides. Here, "containing water-soluble polysaccharides" means that the water-soluble polysaccharides are contained in the present powdered plant protein material in a state where they are integrated with other components such as proteins and cannot be physically separated, i.e., in a complex state. In this regard, a mixture of powdered plant protein material and powdered water-soluble polysaccharides in powder form does not fall under the present powdered plant protein material. In this specification, the specific water-soluble polysaccharides contained in the present powdered plant protein material may be referred to as "the present water-soluble polysaccharides."

[0030] The water-soluble polysaccharide is a water-soluble bean polysaccharide, or alginic acid or a salt thereof. Preferred water-soluble bean polysaccharides include water-soluble soybean polysaccharides and water-soluble pea polysaccharides. Examples of alginic acid or a salt thereof include sodium alginate and potassium alginate. When the water-soluble polysaccharide is contained in the powdered vegetable protein material, the water-soluble polysaccharide may inhibit the three-dimensional structure of the vegetable protein, and therefore may be effective in preventing the influence of the vegetable protein on gluten formation in bread dough.

[0031] Water-soluble soybean polysaccharides and water-soluble pea polysaccharides are water-soluble polysaccharides composed of sugars such as rhamnose, fucose, arabinose, xylose, galactose, glucose, and uronic acid. They generally have an average molecular weight of 1,000,000 or less when analyzed by gel filtration HPLC under the following conditions. These polysaccharides can be prepared by extracting with water from raw materials containing insoluble dietary fiber (okara) from soybeans or peas using known methods, followed by purification as necessary. Commercially available water-soluble soybean polysaccharides include the "SOYAFIBE®" series (manufactured by Fuji Oil Co., Ltd.) and the "SM" series (manufactured by San-Ei Gen F.F.I.). Commercially available water-soluble pea polysaccharides can also be obtained by the methods described in International Publication Nos. WO 2012 / 176852 and WO 2014 / 103833.

[0032] Gel filtration HPLC was performed using standard pullulan (Showa Denko K.K.) as the standard substance and an analytical column "TSKgel G5000PWXL" (Tosoh Corporation, column size: 7.8 mm ID x 30 cm, packing base: methacrylate polymer, packing particle size: 10 μm, molecular weight exclusion limit: 2.5 million). The average absolute molecular weight (MM) was determined by multi-angle laser light scattering (MALLS) calibrated with toluene after passing through the column. The eluent used was, for example, 50 mM sodium acetate aqueous solution (pH 5.0), the column flow rate was 1.0 mL / min, and the detectors were an RI detector and a MALLS detector. However, the analytical conditions may be changed as appropriate as long as they do not result in significant errors in the analytical values.

[0033] Alginic acid or its salts are water-soluble polysaccharides derived from seaweed, and commercially available products can be used. As the salts, alkali metal salts such as sodium and potassium salts are preferred.

[0034] The content of the water-soluble polysaccharide in the solid content of the powdered vegetable protein material is preferably 0.5% by weight or more. In a more preferred embodiment, the content may be 0.5% by weight or more, or 1% by weight or more. In some embodiments, the upper limit of the content may be 5% by weight or less, 4% by weight or less, or 3% by weight or less.

[0035] (Manufacturing powdered vegetable protein materials) Below, a reference embodiment for producing a powdered vegetable protein material that satisfies all of requirements A) to E) of the present invention is shown using soybeans as an example. However, the technical concept of the present invention is essentially to apply this powdered vegetable protein material that satisfies requirements A) to E) to the production of bread. Therefore, it goes without saying that the method for producing this powdered vegetable protein material is not limited to a specific type of plant or a specific production embodiment. The powdered soy protein material can be produced based on the conventional process for producing isolated soy protein as described below, but the protein can be concentrated by a general acid precipitation method, a concentration method using membrane filtration, or a method of extracting concentrated soy protein with water. Defatted soybeans are generally used as the soybean raw material for protein extraction, but full-fat soybeans or partially defatted soybeans can also be used. When full-fat soybeans or partially defatted soybeans are used, high-speed centrifugation is performed after the extraction process to remove the oil that separates to the top layer, resulting in low oil fractionation. Next, the soybean raw material is mixed with water, dispersed into a slurry state, and the protein is extracted while stirring as necessary. Next, the insoluble dietary fiber (okara) is removed from the slurry using a separation means such as a centrifuge or filtration to obtain an extracted soy protein solution (soy milk). Next, acid-soluble fractions (whey), such as oligosaccharides and acid-soluble proteins, are removed from the extracted soy protein solution to obtain a soy protein concentrate. A typical method is acid precipitation, in which the pH of the extracted soy protein solution is adjusted to near its isoelectric point of 4 to 5 using an acid such as hydrochloric acid or citric acid, thereby insolubilizing and precipitating the protein. The acid-soluble fraction is then removed by a separation method such as centrifugation or filtration, and the acid-insoluble fraction, known as "curd," is recovered and re-dispersed in an appropriate amount of water to obtain a curd slurry. Other methods for concentrating soy protein besides acid precipitation include ultrafiltration. The resulting curd slurry is then adjusted to a pH of approximately 7 to obtain a neutralized slurry. Heat sterilization is then performed by at least one high-temperature heat treatment during all steps. The heat treatment is preferably a direct steam injection type high-temperature instantaneous heat treatment. This heat treatment is a UHT sterilization method in which high-temperature, high-pressure steam is directly injected into the soy protein solution, the solution is heated and maintained, and then the pressure is suddenly released in a vacuum flash pan. The heat treatment conditions are 100 to 170°C, preferably 110 to 165°C, and the heating time is 0.5 seconds to 5 minutes, preferably 1 second to 120 seconds. The soy protein-containing solution or slurry to be heat-treated is heat-treated at a pH in the range of 3 to 12, depending on the pH adjusted at each stage of the production process. A commercially available heat sterilization device suitable for this heat treatment method can be used, such as a VTIS sterilizer (manufactured by Alfa Laval) or a jet cooker. Finally, the sterilized solution is spray-dried using a spray dryer or the like to obtain a powdered soy protein material. As a drying method using a spray dryer, either a disk-type atomizer method or spray drying using a one-fluid or two-fluid nozzle can be used. In order to obtain a powdery soy protein material that satisfies all of the requirements A) to E) of the present invention, the following steps are optionally or essentially adopted. As an optional embodiment, in the step of removing insoluble dietary fiber from the slurry after the extraction step to obtain an extracted soy protein solution, long-term centrifugation or multiple centrifugations are performed so that the mixing of insoluble dietary fiber is minimized, and the content of insoluble dietary fiber is 1% by weight or less, preferably 0.5% by weight or less, more preferably 0.2% by weight or less in the final powdered soy protein material of the product, and can be removed. As another embodiment, it is also possible to select not to add the above steps. One of the essential steps in the manufacturing process of this powdered plant-based protein material is the addition of this water-soluble polysaccharide. The addition of this water-soluble polysaccharide is achieved by adding it to the solution containing plant-based protein in a step before the spray drying step during the manufacturing process of this powdered plant-based protein material and mixing well. As a result, this water-soluble polysaccharide becomes integrated and complexed in a state where it cannot be physically separated from this powdered plant-based protein material.

[0036] This powdered plant-based protein material that satisfies all of the above requirements A) to E) can be obtained by purchasing it from a manufacturer of plant-based protein materials, such as Fuji Oil Co., Ltd., or by commissioning the manufacturer to produce it. Incidentally, Fuji Oil Co., Ltd. has already been able to pilot-produce the "Proline CP01" (tentative name) series as a new powdered plant-based protein material having all of the above characteristics A) to E). Therefore, those skilled in the art can easily obtain the product or test sample by specifying this. Note that the conventional commercially available powdered soy protein materials such as the "Fujipro" series, "New Fujipro" series, "Proline" series, etc. do not correspond to the powdered plant-based protein materials that satisfy all of the above characteristics A) to E). Therefore, even if these are used, they cannot be applied to the manufacturing method of this bread.

[0037] (Measurement method) The analytical values in the present invention shall follow the following measurement methods. <Measurement method of pH> Add 360 ml of ion-exchanged water at 25°C to 40 g of the sample, and stir with a homomixer for 5 minutes to completely dissolve it. Measure the resulting solution with an arbitrary pH meter.

[0038] <Measurement method of NSI> Add 60 ml of water to 3 g of the sample, stir with a propeller at 37°C for 1 hour, then centrifuge at 1400×g for 10 minutes, and collect the supernatant (I). Next, add 100 ml of water again to the remaining precipitate, stir with a propeller at 37°C for 1 hour again, then centrifuge and collect the supernatant (II). Combine the (I) solution and the (II) solution, add water to the mixture to make 250 ml. Filter this through filter paper (NO.5), and then measure the nitrogen content in the filtrate by the Kjeldahl method. At the same time, measure the nitrogen amount in the sample by the Kjeldahl method, and NSI is defined as the ratio of the nitrogen amount (water-soluble nitrogen) recovered as the filtrate to the total nitrogen amount in the sample, expressed as weight%.

Example

[0039] Hereinafter, embodiments of the present invention will be described more specifically by way of examples and the like. In the examples, “%” and “parts” indicate “weight %” and “parts by weight” unless otherwise specified. In addition, all kinds of powdery protein materials used in the examples and the like were commercially available products and test-manufactured products manufactured by Fuji Oil Co., Ltd.

[0040] ■Test materials As samples of powdery soy protein materials, commercially available product A of a general non-decomposed type that has not been enzymatically decomposed by protease, commercially available product B that has been enzymatically decomposed, and commercially available products C and D with the addition of a divalent metal salt were prepared. Next, a trial product E “Prolina CP01” (tentative name) newly manufactured as a powdery soy protein material was prepared. All of these are powdery isolated soy proteins in which protein is extracted with water using defatted soybeans as raw materials and finally spray-dried, and can be obtained by inquiring Fuji Oil Co., Ltd. Analyses were performed on the protein content in the solid content of these powdery soy protein materials, the pH of the 10% solution, NSI, TCA solubility rate, calcium content, and magnesium content. The respective analysis values are shown in Table 1 below.

[0041] (Table 1) TIFF0007726064000001.tif59153

[0042] ■ Test Example 2 (Tests T10 to T15) As a control, a rolled bun was produced by the sponge method without adding the test ingredients in Table 1, using the formulation in Table 2 and the manufacturing conditions in Table 3 (C1). Next, as test batches, rolled buns were produced using each of the powdered soy protein ingredients of commercial products A to D and prototype E, using the formulation in Table 2 and the manufacturing conditions in Table 3 (T1 to T5).

[0043] (Table 2) TIFF0007726064000002.tif104146

[0044] (Table 3) TIFF0007726064000003.tif107146

[0045] Specific volume of each roll (cm 3 / g) and the workability during bread making was evaluated. In addition, 10 panelists who are skilled in the sensory evaluation of bread were asked to taste the buns from each test group and conduct a sensory evaluation of the "texture of the bread" and "flavor of the bread." The evaluation method was to compare each test plot with the control plot, with the test plot with the quality furthest from the control plot C1 being given a score of 1, the test plot with the quality most similar to the control plot C1 being given a score of 5, and test plots with quality levels in between being given scores of 1 to 5 by consensus of the panelists, taking into account the sense of distance between the 1-point quality and the 5-point quality. In addition, the prototype maker similarly evaluated the workability using a score of 1 to 5. The results are shown in Table 4, and based on these results, the suitability of each powdered protein ingredient as an ingredient for bread making was comprehensively judged.

[0046] (Table 4) TIFF0007726064000004.tif44153

[0047] (Table 5) TIFF0007726064000005.tif85151

[0048] (Consideration) As can be seen from Tables 4 and 5, only test group T5, which added prototype E as a powdered soy protein ingredient, had bread quality that was comparable to that of control group C1 in terms of workability, specific volume, texture after baking, and flavor, despite having a high protein content. Breads containing commercial powdered soy protein ingredients A to D were found to be unsuitable because they showed significant differences from the control C1 in terms of dough extensibility and specific volume during the mixing stage, and the texture and flavor of the bread after baking.

Claims

1. Bread containing 5 to 20% by weight of vegetable protein based on flour, A method for producing bread dough comprising adding a powdered vegetable protein material that satisfies at least all of the following requirements A) to E) as a vegetable protein source to the dough: A method for producing protein-enriched breads. A) The protein content in the solid content is 80% by weight or more, B) The pH of a 10% by weight solution is pH 6 to 8, C) Nitrogen Solubility Index (NSI) of 25 or less; D) 0.22M trichloroacetic acid solubility is 5% or less; E) Contains water-soluble bean polysaccharides, or alginic acid or a salt thereof.

2. 2. The method for producing breads according to claim 1, wherein the powdered vegetable protein material is selected from the group consisting of soybeans, peas and mung beans.

3. 3. The method for producing breads according to claim 1 or 2, wherein the protein content of the solid matter in the powdered vegetable protein material is 85% by weight or more.

4. 4. The method for producing bread according to claim 1, wherein a 10% by weight solution of the powdered vegetable protein material has a pH of 6.7 to 7.

3.

5. 5. The method for producing bread according to claim 1, wherein the powdered vegetable protein material has a calcium content of 0.5% by weight or less and a magnesium content of 0.25% by weight or less in the solid content thereof.

6. 6. The method for producing breads according to claim 1, wherein the polysaccharide contained in the powdered vegetable protein material is a water-soluble pulse polysaccharide.

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