TWI909551B - Bread with high protein content and containing acetic acid, bread flour mixture and bread manufacturing method - Google Patents

Abstract

This invention discloses a bread containing at least 30% by weight of protein and acetic acid (on a dry weight basis), with reduced sourness and rancidity.

The aforementioned bread is obtained from a dough containing at least 30% by weight of protein, acetic acid, and amylase per dry weight of the dough.

Description

Bread with high protein content and containing acetic acid, bread flour mixture and bread manufacturing method

This disclosure relates to a bread containing at least 30% by weight of protein and acetic acid on a dry weight basis, with reduced sourness and odor. Furthermore, this disclosure relates to a bread flour mix used in the manufacture of the aforementioned bread, and a method for manufacturing the aforementioned bread.

In recent years, with the advancement of the times, people's health awareness has increased, and protein is one of the nutrients they pay the most attention to and consume. On the other hand, bread is considered a staple food or snack in daily life, so increasing the protein content of bread is effective for efficient protein intake. In the past, various technologies for manufacturing bread with increased protein content have been published (invention patents 1 and 2, etc.).

On the other hand, the shelf life of ordinary bread is about 3 to 5 days, leading to increased demand for long-shelf-life bread (14 to 60 days) as a staple food, preserved food, and emergency food. In long-shelf-life bread, organic acids such as acetic acid are sometimes added to impart antibacterial properties and improve shelf life. [Prior Art Documents] [Invention Patent Documents]

Invention Patent Document 1: Japanese Patent Application Publication No. 2023-42298; Invention Patent Document 2: Japanese Patent Application Publication No. 2020-103200

[Problem to be solved by the invention] Bread containing more than 30% protein and acetic acid by weight (in dry weight conversion) is beneficial in terms of nutritional value and preservation. However, it has the drawback of producing a sour or rancid taste due to acetic acid, which prevents it from fully possessing the original aroma of bread.

Therefore, the problem disclosed herein is to provide a bread containing more than 30% by weight of protein and acetic acid (based on dry weight conversion), with reduced sourness and rancidity. [Means used to solve the problem]

To address the aforementioned issues, the inventors of this case diligently reviewed and developed a bread product that, starting from a high-protein content and excellent shelf life, utilizes dough containing at least 30% by weight of protein, acetic acid, and amylase (based on dry weight conversion). This bread product suppresses the sour taste and odor caused by acetic acid. Furthermore, the invention addresses the drawback of adding whole wheat flour to increase protein content or nutritional value, which produces a bran-like or bean curd-like odor. Even when containing whole wheat flour, the bread product effectively suppresses these odors. Furthermore, it was discovered that when soybean flour was added to increase protein content or nutritional value in the past, it produced a beany odor (a smell similar to wheat bran or soybean residue). In the aforementioned bread, this beany odor can be suppressed by adjusting the amount of amylase added. Moreover, the inventors have developed a bread with the aforementioned characteristics where, under specific conditions, the molecular weight distribution of sugars meets the following requirements: the proportion of sugars with a molecular weight of 1,000 to 3,000 relative to the total sugar content is less than 23%, and the proportion of sugars with a molecular weight of less than 1,000 is more than 57%. This disclosure is based on further repeated review of these insights.

That is, this disclosure provides an invention in the manner described below. Item 1. A bread obtained from a dough comprising at least 30% by weight of protein, acetic acid, and amylase per dry weight of the dough. Item 2. The bread as described in Item 1, wherein the aforementioned dough comprises whole wheat flour and/or soy flour. Item 3. The bread as described in Item 1 or 2, wherein the aforementioned amylase is α-amylase. Item 4. A bread blend containing at least 30% by weight of protein, acetic acid, and amylase. Item 5. A method for manufacturing bread, comprising: a step of preparing a dough by adding water to bread flour as described in Item 4; and a step of fermenting and baking the dough obtained in the aforementioned step. Item 6. A type of bread obtained from a dough comprising at least 30% by mass of protein and acetic acid per dry mass of dough; The molecular weight distribution of carbohydrates determined under the following conditions satisfies the following requirement: the proportion of carbohydrates with a molecular weight of 1,000 or more but less than 3,000 is less than 23%, and the proportion of carbohydrates with a molecular weight of less than 1,000 is more than 57%; <Determination conditions for molecular weight distribution of carbohydrates> (1) Finely chop 0.05 g of bread and add 10 mL of 0.1 mol/L sodium nitrate solution, let stand overnight at room temperature, and then filter using a membrane filter; (2) Feed the resulting filtrate to HPLC (High-Performance Liquid Chloride) using a sieve column of a specified size. Chromatography (high performance liquid chromatography) is used to obtain chromatograms; the molecular weight of each peak is obtained by using calibration curves prepared using polytriglucose and maltotriose with known molecular weights as standards; (3) the peak area with a molecular weight of 1,000 or higher but less than 3,000 relative to the total peak area is calculated as the ratio of sugars with a molecular weight of 1,000 or higher but less than 3,000 relative to the total sugar content; and the peak area with a molecular weight of less than 1,000 relative to the total peak area is calculated as the ratio of sugars with a molecular weight of less than 1,000 relative to the total sugar content. [Efficacy of the Invention]

The bread disclosed herein contains a high content of protein and acetic acid, and suppresses the sour taste and odor caused by acetic acid. Furthermore, according to one embodiment of the bread disclosed herein, although it contains whole wheat flour, the bran and soybean residue odor caused by it is still suppressed. Moreover, according to another embodiment of the bread disclosed herein, although it contains soy flour, the soybean odor caused by it is still suppressed. In one embodiment of the bread disclosed herein, acetic acid not only improves shelf life but also makes it easier to use soybeans, thus providing bread with long shelf life containing soybeans, which contributes to the achievement of SDGs 2 "to eliminate hunger, ensure food security and improve nutrition, and promote sustainable agriculture" and SDGs 9 "to establish infrastructure for industrial and technological innovation".

1. Definitions Unless otherwise specified, the terms used in this disclosure shall be understood to have the meaning commonly used in the art field to which they pertain. Therefore, unless otherwise defined, all technical and scientific terms used in this specification shall have the same meaning as commonly understood by one of ordinary skill in the art field to which this disclosure pertains.

In this disclosure, the content of each component or raw material contained in bread refers to the content of each component or raw material when the bread is converted to dry mass, and is the ratio of the content of each component or raw material contained in bread to the total amount of components other than moisture. Furthermore, in this disclosure, the content of each component or raw material contained in bread is obtained as a ratio relative to the dry mass (total mass of the dough used in the manufacture of bread) of the aforementioned dry mass of each component or raw material contained in the dough.

In this disclosure, the content of each component or raw material contained in the bread blend is the content of each component or raw material when the bread blend is converted to dry mass, and is the ratio of the dry mass of each component or raw material contained in the bread blend to the total amount of components other than moisture.

2. Bread (1) One embodiment of the bread disclosed herein is a bread obtained from a dough comprising at least 30% by mass of protein, acetic acid, and amylase per dry mass of the dough. The bread disclosed herein will be described in detail below.

[Protein] The bread disclosed herein is obtained from a dough containing at least 30% by weight of protein per dry weight of the dough. In this disclosure, the protein content in the dough is the total amount of protein contained in the raw materials that serve as the protein source within the dough.

There are no particular limitations on the types of proteins used in this disclosure. Examples include wheat protein, soy protein, egg protein, milk protein, rice protein, pea protein, corn protein, barley protein, and rye protein. One of these proteins may be used alone, or in combination of two or more.

In the bread disclosed herein, any raw materials that correspond to the type of protein contained therein can be added to the dough to serve as the source of that protein.

Raw materials that can serve as a source of wheat protein include, for example, wheat flour and wheat gluten. Wheat flour can be refined wheat flour or whole wheat flour. Wheat flour can be made from either durum or soft wheat, and can also be made from low-gluten, medium-gluten, or high-gluten flour. A preferred example of such grain flour is wheat flour, and more preferably, whole wheat flour. Whole wheat flour typically contains approximately 10–18% protein by weight. Wheat gluten is a network of gliadin and glutenin contained in wheat flour. In this disclosure, dried active gluten can be used as wheat gluten. Active gluten typically contains about 60-90% protein by weight.

Raw materials that can serve as a source of soy protein include, for example, soy flour, concentrated soy protein, and isolated soy protein. Soy flour is a raw material made by grinding soybeans into powder form. In this disclosure, heat-treated, deactivated soy flour can be used as soy flour. Soy flour typically contains approximately 35-45% protein by weight. Concentrated soy protein is a raw material obtained by concentrating the protein from soybeans. Isolated soy protein is a raw material from which only the protein is extracted from soybeans. Among the raw materials that can serve as a source of soy protein, soy flour is a preferred example.

Raw materials that can serve as a source of egg protein include, for example, egg yolk powder, egg white powder, and egg white separated from eggs. Egg yolk powder is a powdered raw material used to dry egg yolks. Egg yolk powder typically contains 25-35% protein by weight. Egg white powder is the raw material obtained by separating egg whites and then pulverizing them. Among the raw materials that can serve as a source of egg protein, egg yolk powder is a prime example.

Raw materials that can serve as sources of milk protein include, for example, skim milk powder, whey, and proteins separated from milk.

Raw materials that can serve as sources of rice protein include, for example, rice flour and protein isolated from rice.

Raw materials that can serve as sources of pea protein include, for example, pea flour and protein isolated from peas.

Raw materials that can serve as sources of corn protein include, for example, corn flour and protein isolated from corn.

Raw materials that can serve as sources of barley protein include, for example, barley flour and proteins isolated from barley.

Raw materials that can serve as sources of rye protein include, for example, rye flour and proteins isolated from rye.

In the bread disclosed herein, the total protein content of the dough is not particularly limited as long as it is 30% or more per dry weight of the dough. Examples include 30-50% by weight, preferably 31-45% by weight, more preferably 32-40% by weight, and especially preferably 34-39% by weight.

The bread disclosed herein preferably contains wheat flour, more preferably whole wheat flour and wheat gluten. Therefore, as a preferred example of the bread disclosed herein, it can be listed that it contains at least wheat protein. Regarding the wheat protein content in the dough of the bread disclosed herein, considering the content of other proteins, the total protein content in the dough only needs to be appropriately set within the range of at least 30% by weight per unit dry weight of the dough. For example, it can be set to 15-35% by weight, more preferably 20-30% by weight, and even more preferably 24-28% by weight.

Furthermore, the bread disclosed herein preferably contains soy protein and/or egg protein in addition to wheat protein, and more preferably contains wheat protein, soy protein, and egg protein.

In the case where the dough contains soy protein, the total soy protein content of the dough should be appropriately set within the range of 30% by weight or more per dry weight of the dough, taking into account the content of other proteins. For example, it can be set to 1-20% by weight, preferably 3-15% by weight, and even more preferably 5-9% by weight.

Furthermore, in the case where the dough contains ovalbumin, the total amount of ovalbumin in the dough should be appropriately set within the range of 30% by weight or more per dry weight of the dough, taking into account the content of other proteins. For example, it can be set to 0.1% to 10% by weight, preferably 0.2% to 5% by weight, and even more preferably 0.5% to 2% by weight.

In the bread disclosed herein, the content of raw materials that serve as protein sources can be set in a manner that satisfies the aforementioned protein content requirements, taking into account the types of raw materials that serve as protein sources or the content of protein.

For example, in this disclosure, the content of wheat flour (including whole wheat flour) in the dough can be listed as 30 to 65% by weight per dry weight of the dough, preferably 40 to 60% by weight, and more preferably 50 to 55% by weight.

Furthermore, in the case where the flour disclosed herein contains active gluten, the content of active gluten in the dough can be, for example, 5 to 40% by mass per dry mass of the dough, preferably 10 to 30% by mass, and more preferably 18 to 23% by mass.

Furthermore, in the case where the dough contains soy flour, the content of soy flour in the dough can be, for example, 5 to 35% by weight in the dry weight of the dough, preferably 10 to 30% by weight, and even more preferably 15 to 20% by weight.

Furthermore, in the case where the dough contains egg yolk powder, the content of egg yolk powder in the dough can be, for example, 0.1 to 15% by weight per dry weight of the dough, preferably 0.5 to 10% by weight, and more preferably 1 to 4% by weight.

[Acetic Acid] In the bread disclosed herein, the dough used during manufacturing contains acetic acid. In the bread disclosed herein, acetic acid plays a role in improving shelf life. In the prior art, bread containing acetic acid would produce a sour or rancid taste and would not fully present the original aroma of the bread. However, in the bread disclosed herein, by containing amylase in the dough, the sour taste and rancid taste are suppressed even though acetic acid is present, thus presenting the original excellent aroma of the bread.

As acetic acid, it can be not only refined acetic acid, but also raw materials containing acetic acid, such as those used in the brewing of vinegar.

The acetic acid content in the dough of the bread disclosed herein can be, for example, 0.01 to 2% by mass per dry mass of the dough, preferably 0.05 to 1% by mass, and even more preferably 0.1 to 0.5% by mass.

[Amylase] The dough used in the manufacture of the bread disclosed herein contains amylase. In a dough containing at least 30% by weight of protein and acetic acid per dry weight, the presence of amylase suppresses the sour taste and odor caused by acetic acid. Furthermore, in the case where the bread disclosed herein contains whole wheat flour, the presence of amylase in the dough also suppresses the bran and bean curd odor caused by whole wheat flour. Moreover, in the case where the bread disclosed herein contains soy flour, by adjusting the amylase content in the dough, the beany odor caused by soy flour can also be suppressed.

There is no particular limitation on the type of amylase used in this disclosure; examples include α-amylase, β-amylase, and glucoamylase. One type of amylase may be used alone, or two or more may be used in combination.

There are no particular limitations on the source of the amylase used in this disclosure. Examples include Bacillus subtilis, Bacillus licheniformis, Bacillus spores, Bacillus cristata, and other Bacillus species; and Aspergillus niger, Aspergillus oryzae, and other Aspergillus species. In this disclosure, the amylase may be used alone or in combination with two or more sources.

As amylases, α-amylase or β-amylase are preferred examples. As α-amylases, those derived from bacillus microorganisms are more preferably α-amylases, particularly those derived from *Bacillus subtilis* or *Bacillus subtilis*. As β-amylases, those derived from bacillus microorganisms are more preferably β-amylases, particularly those derived from *Bacillus cristata*.

In the bread disclosed herein, the amylase content in the dough can be appropriately set by taking into account the type of amylase used and the duration of amylase action during bread production. For example, the amylase content in 1g of dried dough can be 0.01–300U, 0.02–200U, 0.1–200U, or 0.1–100U. From the perspective of effectively suppressing sourness and odor, and further, in the case of whole wheat flour, effectively suppressing the bran and soybean residue odor originating from whole wheat flour, the following can be cited: per 1g of dry weight of dough, the amylase content should be 0.03-200U or 0.1-50U, preferably 0.4-30U, more preferably 1-30U, even more preferably 2-25U, particularly preferably 3-20U, and most preferably 3.5-10U. Furthermore, if the amylase content in the dough is 1U or more per 1g of dry weight of dough, preferably 2U or more, and more preferably 3U or more, even if soy flour is included, the soybean odor originating from soy flour can still be effectively suppressed. Here, in the case of α-amylase, the activity unit 1U is the activity achieved by decomposing 1 mL of 1 w/v% starch solution into a soluble starch matrix at 40°C and pH 5.0 for 30 minutes until the iodine colorimetric transmittance reaches 66% at a wavelength of 670 nm and a light path length of 10 mm. Furthermore, in the case of β-amylase, the activity unit 1U is the amount of enzyme that increases the reducing power of glucose by the equivalent of 1 mg in 1 minute. Specifically, the aforementioned "1 unit" for β-amylase is the value measured according to the starch saccharification power determination method recorded in the fourth edition of the Existing Additive Self-Management Specification (Japan Food Additives Association, issued October 16, 2008).

[Sodium Chloride] In addition to the aforementioned ingredients, the bread disclosed herein may also contain sodium chloride. When the bread disclosed herein contains sodium chloride, the sodium chloride content in the dough may be, for example, 0.05 to 5% by mass per dry weight of the dough, preferably 0.1 to 3% by mass, and more preferably 0.2 to 1% by mass.

[Yeast] The bread disclosed herein contains yeast required for fermentation. The yeast can be any type of bread yeast, but brewer's yeast may also be included depending on the need. Furthermore, the yeast can be any type of dry yeast, instant dry yeast, or live yeast. One type of yeast may be used alone, or two or more may be used in combination.

In the bread disclosed herein, the yeast content as part of the dough may be, for example, 0.1 to 5% by weight per dry mass of the dough, preferably 0.3 to 3% by weight, and more preferably 0.5 to 2% by weight.

[Other Ingredients] The bread disclosed herein may also contain ingredients other than those mentioned above. As for other ingredients that may be included in the bread disclosed herein, they can be appropriately set from the food materials or additives used in the manufacture of general bread, corresponding to the quality, flavor, and texture that should be imparted. Such raw materials include, for example: sugar, reduced syrup, white sugar, liquid sugar, powdered syrup, syrup, artificial sweeteners, etc.; ghee, margarine, butter, powdered fats, spreads, lard, salad oil, olive oil, emulsified fats, etc.; chocolate, cheese, yogurt, baking powder, yeast activator, brine, gelatin, tea, alcohol, emulsifiers, spices, spirits, dried fruit, nuts, flavorings, dietary fiber, leavening agents, dough improvers, antioxidants, pH adjusters, preservatives, acidulants, etc. These raw materials can be used individually or in combination of two or more.

[Bread Manufacturing] The bread disclosed herein can be made using the aforementioned ingredients and an appropriate amount of water to form dough, and then manufactured through steps such as fermentation (first fermentation, second fermentation), dividing, shaping, post-fermentation (second fermentation), and baking. Although not intended to be limiting, the bread manufacturing process disclosed herein can be considered to involve an enzymatic reaction produced by amylase in the dough during the steps from dough preparation to baking, thereby achieving the inhibition of sour taste and odor, as well as the inhibition of other odors such as bran and soybean residue.

Furthermore, the content of ingredients other than water remains almost unchanged between the dough and the bread made from the aforementioned dough. Therefore, in the bread disclosed herein, the content of each ingredient per dry mass of the bread is almost the same as the content of each ingredient per dry mass of the dough used in the production of the bread.

[Types of Bread] There are no particular limitations on the types of bread disclosed herein. Examples include: toast, round bread, dinner rolls, croissants, butter rolls, whole loaves of toast, muffins, French bread, and other sweet breads.

3. Bread Mixture This disclosure further provides a bread mix containing at least 30% by weight of protein, acetic acid, and amylase per dry weight. The bread mix of this disclosure is a mixture of the aforementioned bread ingredients, and by using the bread mix of this disclosure, the aforementioned bread can be easily manufactured.

The types or amounts of ingredients contained in the bread mix disclosed herein are as described in the preceding paragraph "2. Bread (part 1)".

The bread is prepared by adding an appropriate amount of water to the bread mix as disclosed herein, and then proceeding with fermentation (first fermentation), dividing, shaping, post-fermentation (second fermentation), and baking to obtain the aforementioned bread.

4. Bread (2) In another embodiment of the bread disclosed herein, there is a bread obtained from a dough containing at least 30% by mass of protein and acetic acid per dry mass of the dough, wherein, under the measurement conditions described below, the molecular weight distribution of sugars satisfies the following condition: the proportion of sugars with a molecular weight of 1,000 or higher but less than 3,000 is 23% or less, and the proportion of sugars with a molecular weight of less than 1,000 is 57% or more, relative to the total amount of sugars. The bread of this embodiment will now be described in detail.

The bread of this embodiment is obtained from a dough containing at least 30% by mass of protein and acetic acid per dry mass of the dough. The types of protein and acetic acid used in the bread of this embodiment are as described in the aforementioned section "2. Bread (1)". Furthermore, the content of protein and acetic acid in the dough of the bread of this embodiment is as described in the aforementioned section "2. Bread (1)".

In the bread of this embodiment, under the following measurement conditions, the molecular weight distribution of sugars satisfies the following condition relative to the total amount of sugars: the proportion of sugars with a molecular weight of 1,000 or higher but less than 3,000 is 23% or less, and the proportion of sugars with a molecular weight of less than 1,000 is 57% or more. By satisfying such a molecular weight distribution, sourness and odor can be suppressed in bread made from dough containing 30% or more by weight of protein and acetic acid per dry weight of the dough. Furthermore, by satisfying such a molecular weight distribution, even when whole wheat flour is included, the bran and bean curd odor originating from whole wheat flour can be suppressed. <Determination conditions for molecular weight distribution of carbohydrates> (1) Finely slice 0.05g of bread and add 10mL of 0.1mol/L sodium nitrate solution. After standing overnight at room temperature, filter using a membrane filter. (2) Feed the obtained filtrate to HPLC using a sieve column of a certain size to obtain a chromatogram. The molecular weight of each peak is obtained by using a calibration curve prepared using polyglucose and maltotriose with known molecular weights as standards. (3) Calculate the peak area with a molecular weight of 1,000 or higher but less than 3,000 relative to the total peak area as the ratio of carbohydrates with a molecular weight of 1,000 or higher but less than 3,000 relative to the total amount of carbohydrates. Furthermore, the ratio of the peak area with a molecular weight of less than 1,000 relative to the total peak area to the total amount of sugars with a molecular weight of less than 1,000 was calculated.

The percentage of sugars with a molecular weight of 1,000 or higher but less than 3,000 relative to the total amount of sugars should be 23% or less, preferably 5-23%, and more preferably 8-23%. In particular, from the viewpoint of effectively suppressing the odor of wheat bran and soybean residue by further including whole wheat flour to enhance the suppression of sourness and odor, and suppressing the odor of soybeans by including soybean flour, the percentage of sugars with a molecular weight of 1,000 or higher but less than 3,000 relative to the total amount of sugars can be 10-20%, particularly preferably 12-18%, and most preferably 12-16%.

The percentage of sugars with a molecular weight of less than 1,000 relative to the total sugar content only needs to be 57% or more, preferably 57-70%. In particular, from the viewpoint of effectively suppressing the smell of wheat bran and soybean residue by further including whole wheat flour to enhance the suppression of sourness and odor, and suppressing the smell of soybean odor when soybean flour is included, the percentage of sugars with a molecular weight of less than 1,000 relative to the total sugar content can be preferably 60-70%, particularly preferably 63-69%, and most preferably 65-68%.

In the bread of this embodiment, there is no particular limitation on the percentage of sugars with a molecular weight of 3,000 or more but less than 10,000 relative to the total amount of sugars. Examples of such percentages include 3% to 30%, more preferably 5% to 11%, and even more preferably 8% to 11%. The percentage of sugars with a molecular weight of 3,000 or more but less than 10,000 relative to the total amount of sugars is a value obtained using the aforementioned conditions for measuring the molecular weight distribution of sugars.

In the bread of this embodiment, there is no particular limitation on the percentage of sugars with a molecular weight of 10,000 or more but less than 30,000 relative to the total amount of sugars. Examples of such percentages include 1% to 15%, more preferably 3% to 10%, and even more preferably 3% to 7% or 5% to 7%. The percentage of sugars with a molecular weight of 10,000 or more but less than 30,000 relative to the total amount of sugars is a value obtained by using the aforementioned conditions for measuring the molecular weight distribution of sugars.

In the bread of this embodiment, there is no particular limitation on the percentage of sugars with a molecular weight of 30,000 or more but less than 100,000 relative to the total amount of sugars. Examples of such percentages include 1% to 10%, more preferably 1% to 5% or 2% to 5%, and even more preferably 1% to 3%. The percentage of sugars with a molecular weight of 30,000 or more but less than 100,000 relative to the total amount of sugars is a value obtained by measuring the molecular weight distribution of sugars as described above.

In the bread of this embodiment, there is no particular limitation on the percentage of sugars with a molecular weight of 100,000 or higher relative to the total amount of sugars. For example, it can be 5% or less, preferably 3% or less, and more preferably 2% or less. The percentage of sugars with a molecular weight of 100,000 or higher relative to the total amount of sugars is a value obtained by measuring the molecular weight distribution of sugars as described above.

In order to meet the aforementioned molecular weight distribution of sugars, the type or content of the added ingredients can be adjusted appropriately. For example, as described in "2. Bread (1)", bread is made by using dough containing more than 30% by weight of protein and acetic acid per dry weight, as well as amylase, thereby appropriately meeting the aforementioned molecular weight distribution of sugars.

In this embodiment of bread, there is no particular limitation on the starch content. For example, the starch content per dry weight of bread is 20-40% by weight, preferably 20-35% by weight, more preferably 20-30% by weight, and even more preferably 24-28% by weight. Here, the starch content of the bread is determined by the following determination conditions. <Determination conditions for starch content> (1) Finely chop 0.05g of bread and add 40mL of 50% volume ethanol aqueous solution, stir and let stand. Then, remove the supernatant and repeat the above operation until the low molecular weight sugars are completely removed. (2) Add 20 mL of ion-exchanged water and 2 mL of 10% sodium hydroxide aqueous solution to the residue after all low-molecular-weight sugars have been removed and heat to gelatinize the residue (starch). Then, neutralize it to pH 7. (3) Next, add starch glucosidase to break down the starch into glucose and measure the amount of glucose in the solution after the reaction. (4) Calculate the amount of starch from the amount of glucose according to the following formula. Taking into account the calculated amount of starch, the mass of the sample, and the dilution ratio during the test, the amount of starch per 1 g of dried bread is obtained. [Formula 1] Amount of starch (g) = Amount of glucose (g) × 0.9

In this embodiment of the bread, there is no particular limitation on the content of free maltose, but it can be listed as, for example, 0.5 to 10% by mass per dry weight of the bread, preferably 1.5 to 10% by mass, more preferably 3 to 8% by mass, and even more preferably 4 to 8% by mass. Similarly, in this embodiment of the bread, there is no particular limitation on the content of free glucose, but it can be listed as, for example, 0.01 to 5% by mass per dry weight of the bread, preferably 0.1 to 2% by mass, more preferably 0.3 to 0.8% by mass, and even more preferably 0.4 to 0.7% by mass. Here, the contents of free maltose and free glucose in the bread are values obtained by the following determination conditions. <Determination conditions for free maltose and free glucose> (1) Finely chop 2.5g of bread and add 30mL of 50% ethanol aqueous solution. Sonicate to dissolve the free maltose and free glucose. Then, add 50% ethanol aqueous solution to make up to 50mL and filter to remove residue. (2) Concentrate the filtrate and use it for HPLC to determine the amount of glucose and maltose. (3) Taking into account the amount of glucose and maltose to be measured, the mass of the sample, and the dilution ratio during the measurement, the free glucose content and free maltose content per 1g of dried bread mass are determined.

The bread of this embodiment contains various raw materials other than protein and acetic acid. The types or contents of raw materials other than protein and acetic acid contained in the bread of this embodiment can be appropriately set in a way that satisfies the aforementioned molecular weight distribution. Appropriate raw materials and contents are as described in the aforementioned paragraph "2. Bread (1)".

The bread of this embodiment can be made from dough containing specific ingredients, and manufactured through steps such as fermentation (single fermentation), dividing, shaping, secondary fermentation, and baking. Furthermore, there is no particular limitation on the type of bread of this embodiment; examples such as those described in the aforementioned "2. Bread (1)" section can be cited. [Example]

The present invention will be illustrated below by way of examples, but the invention is not limited to these examples.

Example 1. Bread Production: Add all ingredients except butter to the mixer listed in Table 1 and mix at low speed for 2 minutes, then at high speed for 7 minutes. Next, add butter and mix at low speed for 1 minute, then at high speed for 7 minutes to obtain dough. Then, ferment at 28°C and 75%RH for 40 minutes. Next, divide the dough into 70g portions, knead each portion to form a shape. Ferment the shaped dough at 38°C and 85%RH for 60 minutes. Afterward, bake in an oven at 210°C (top and bottom heat) for 12 minutes, then cool at room temperature for 40 minutes to obtain round bread. The cooled round bread is packaged together with the quality preserver and stored at 30°C.

[Table 1]

2. Evaluation Method: Sensory evaluation was conducted on bread stored at 30°C for 3 days from the date of manufacture. First, bread from Reference Example 1 (without whole wheat flour and deactivated soy flour) and Comparative Example 1-1 (containing whole wheat flour and deactivated soy flour) were tasted to assess the characteristics of bran, bean curd odor (a smell similar to bran or bean curd), and bean odor (a beany smell). The sourness and sour odor were also evaluated. Next, bread from Comparative Example 1-2 (containing whole wheat flour, deactivated soy flour, and acetic acid) was tasted to assess the characteristics of the sourness and sour odor (the smell of acetic acid) caused by the presence of acetic acid. The bran, bean curd odor, and bean odor were also evaluated. Next, the breads from Examples 1-1 and 1-2 (containing whole wheat flour, deactivated soy flour, acetic acid, and α-amylase) were tasted, and the various aromas of sourness, staleness, wheat bran, soybean residue, and soybean odor were evaluated. Each evaluation was conducted by seven evaluators familiar with the sensory evaluation of bread, using the following evaluation criteria and a nine-stage evaluation process, and the average score was calculated. Furthermore, based on the consensus of the seven evaluators, the following judgment criteria were used to evaluate the improvement effects of sourness, staleness, wheat bran, soybean residue, and soybean odor on the breads from Examples 1-1 and 1-2.

(Fragrance evaluation criteria) 1: No fragrance detected. 2: Almost no fragrance detected. 3: Slight fragrance detected. 4: Slight fragrance detected. 5: Fragrance detected. 6: Slightly strong fragrance detected. 7: Strong fragrance detected. 8: Quite strong fragrance detected. 9: Very strong fragrance detected.

(Criteria for judging the effect of fragrance improvement) A: Effective. B: Slightly effective. C: Ineffective. D: Excessive effect that diminishes the value of the fragrance.

3. Evaluation Results Table 2 shows the evaluation results for the aroma of each bread. In the bread blended with whole wheat flour and deactivated soy flour, with a protein content increased to 30% by weight or more (Comparative Example 1-1), the aroma of wheat bran, soybean residue, and soybean odor increased. Furthermore, in the bread blended with whole wheat flour and deactivated soy flour, with a protein content increased to 30% by weight or more, and also containing acetic acid (Comparative Example 1-2), in addition to the aroma of wheat bran, soybean residue, and soybean odor, the sourness and sour odor also increased. In contrast, breads containing whole wheat flour and deactivated soybean flour with a protein content exceeding 30% by weight, and further containing acetic acid and α-amylase (Examples 1-1 and 1-2), exhibited suppressed sourness and odor, as well as suppressed bran and soybean residue odor. In particular, bread containing 3.94 U/g of α-amylase (Example 1-2) showed significantly enhanced improvement in sourness, odor, and bran and soybean residue odor, and the suppression of soybean odor was also recognized.

[Table 2]

Experimental Example 2 1. Bread Manufacturing Except for the ingredients listed in Table 3, round bread was manufactured under the same conditions as in Experimental Example 1 above.

[Table 3]

2. Evaluation Method Bread stored at 30°C for 3 days after manufacturing was consumed, and its sourness and odor (taste of acetic acid) were evaluated using the following criteria. The evaluation of sourness and odor was based on the following benchmarks, with a minimum increment of 0.5 points within a range of 0.0 to 5.0 (0.0 points for the weakest sourness or odor, and 5.0 points for the strongest). Evaluation was conducted by 5 individuals skilled in sensory evaluation of taste, and the average score was calculated. (Benchmarks for sourness or odor) 0.0 point: No sourness or odor detected at all. 1.0 point: The intensity of sourness or odor detected when consuming the bread of Reference Example 2-1 (without acetic acid). Almost no sourness or odor detected. 2.0 point: Intensity of sour or sour smell perceived when consuming the bread of Reference Example 2-2 (containing 0.2% acetic acid per dry weight of dough). Slightly perceived sour or sour smell. 3.0 point: Intensity of sour or sour smell perceived when consuming the bread of Comparative Example 2 (containing 0.3% acetic acid per dry weight of dough). Slightly strong perceived sour or sour smell. 4.0 point: Intensity of sour or sour smell perceived when consuming the bread of Reference Example 2-3 (containing 0.4% acetic acid per dry weight of dough). Significantly strong perceived sour or sour smell. 5.0 point: Very strong perceived sour or sour smell.

3. Evaluation Results Table 4 shows the evaluation results for the aroma of each bread. In breads containing whole wheat flour and deactivated soybean flour with a protein content of 30% by weight or more (Ref. Examples 2-1 to 2-3, Comparative Example 2), the sourness and odor increased with the addition of acetic acid. In contrast, in breads containing whole wheat flour and deactivated soybean flour with a protein content of 30% by weight or more, and containing acetic acid and α-amylase or β-amylase (Examples 2-1 and 2-2), the sourness and odor were suppressed. Furthermore, although the α-amylase used in Example 2-1 has a different source than the α-amylase used in Examples 1-1 and 1-2, it can suppress the sour taste and odor caused by acetic acid, so it is known that the α-amylase can be used regardless of its source.

[Table 4]

Experimental Example 3 1. Bread Manufacturing Except for the ingredients listed in Table 5, round bread was manufactured under the same conditions as in Experimental Example 1 above.

[Table 5]

2. Evaluation Method: Bread stored at 30°C for 3 days after manufacturing was consumed, and the bran, bean curd-like odor, and bean odor (beany smell) were evaluated using the following criteria. The evaluation of bran, bean curd, and bean odor was based on the following benchmarks, with a minimum increment of 0.5 points within a range of 1.0 to 5.0 (1.0 points for the weakest bran, bean curd, or bean odor, and 5.0 points for the strongest). The evaluation was conducted by 5 individuals skilled in sensory evaluation of flavor, and the average score was calculated. (Benchmark points for sour or sour smell) 1.0 point: Intensity of the bran, soybean residue, or bean odor perceived when consuming the bread of Reference Example 3-1 (without added deactivated soybean flour). Almost no bran, soybean residue, or bean odor perceived. 2.0 point: Intensity of the bran, soybean residue, or bean odor perceived when consuming the bread of Reference Example 3-2 (containing 8.9% by weight of deactivated soybean flour per dry weight of dough). Slightly perceptible bran, soybean residue, or bean odor. 3.0 point: Intensity of the bran, soybean residue, or bean odor perceived when consuming the bread of Comparative Example 3 (containing 17.5% by weight of deactivated soybean flour per dry weight of dough). Slightly strong bran, soybean residue, or bean odor perceived. 4.0 point: The intensity of the bran, soybean residue, or bean odor perceived when consuming the bread of Reference Example 3-3 (the dough contains 26.1% by weight of deactivated soybean flour per dry weight). A distinctly strong perception of the bran, soybean residue, or bean odor. 5.0 point: An extremely strong perception of the bran, soybean residue, or bean odor.

3. Evaluation Results Table 6 shows the evaluation results for the aroma of each bread. In breads containing whole wheat flour and deactivated soybean flour with a protein content of 30% by weight or more (see Examples 3-2, 3-3, and Comparative Example 3), the aromas of wheat bran, soybean residue, and soybean increased with the amount of deactivated soybean flour added. In contrast, in breads containing whole wheat flour and deactivated soybean flour with a protein content of 30% by weight or more, and containing acetic acid and α-amylase (Examples 3-1 to 3-3), the aromas of wheat bran, soybean residue, and soybean were suppressed.

[Table 6]

Experimental Example 4 1. Bread Manufacturing Except for the ingredients listed in Table 7, round bread was manufactured under the same conditions as in Experimental Example 1 above.

[Table 7]

2. Evaluation Method: Bread stored at 30°C for 3 days after manufacturing was consumed, and its sourness, rancidity (the smell of acetic acid), wheat bran odor, bean curd odor (the smell of wheat bran or bean curd), and bean odor (a beany smell) were evaluated. The sourness and rancidity were evaluated under the same conditions as in Test Example 2. The bread used as the benchmark for evaluating sourness and rancidity was also the same as in Test Example 2. Similarly, the wheat bran, bean curd odor, and bean odor were evaluated under the same conditions as in Test Example 3. The bread used as the benchmark for evaluating wheat bran, bean curd odor, and bean odor was also the same as in Test Example 3.

3. Evaluation Results Table 8 shows the evaluation results of the aroma of each bread. The results confirm that even when the types of whole wheat flour and deactivated soybean flour are changed, in breads containing whole wheat flour and deactivated soybean flour and with the protein content increased to more than 30% by weight, the sour taste, sour smell, bran smell, bean curd smell, and bean smell can still be suppressed in breads containing acetic acid and α-amylase (Examples 4-1 and 4-2).

[Table 8]

Experimental Example 5 1. Bread Manufacturing Except for the ingredients listed in Table 9, round bread was manufactured under the same conditions as in Experimental Example 1 above.

[Table 9]

2. Evaluation Method: Bread stored at 30°C for 3 days after manufacturing was consumed, and its sourness and odor (taste of acetic acid) were evaluated. The sourness and odor were evaluated under the same conditions as in Example 2 above. The bread used as the benchmark for evaluating sourness and odor was also the same as in Example 2 above.

3. Evaluation Results Table 10 shows the evaluation results of the aroma of each bread. The results showed that in breads containing whole wheat flour and deactivated soybean flour with a protein content of more than 30% by weight, even the addition of acetic acid, maltose, or galactooligosaccharides could not suppress the sour and rancid taste.

[Table 10]

Example 6 1. Evaluation Methods For each bread from Examples 1-1 to 1-2 and Comparative Example 1-1, the contents of free glucose, free maltose, total glucose (hydrolyzed glucose), and starch were determined using the following methods. Furthermore, for each bread from Comparative Examples 1-2, 3, 4-1, 4-2, 5-1, 5-2, Reference Examples 3-1 to 3-3, and Examples 1-1, 1-2, 2-1, 3-2, 3-3, 4-1, 4-2, the molecular weight distribution of the sugars contained in the bread was determined using the following methods.

1-1. Determination of Free Glucose and Free Maltose Content: Place 2.5g of finely chopped bread into a beaker, then add 30mL of 50% ethanol aqueous solution and ultrasonically treat for 30 minutes. Next, add 50% ethanol aqueous solution in a total volume of 50mL and filter using filter paper (No. 5B). Quantitatively transfer a portion of the filtrate to a flask, and dry it by depressurization using an evaporator. Add water to prepare a 5-fold concentrate (1/5 the volume of the filtrate in the flask). Filter the resulting concentrate using a 0.45μm membrane filter. The obtained filtrate was subjected to HPLC under the following conditions to determine the glucose and maltose content. Taking into account the measured glucose and maltose content, the mass of the sample, and the dilution ratio during the determination, the free glucose and free maltose content per 1g of dried bread was obtained. (HPLC Conditions) • Analytical Apparatus: LC-20AD (Shimadzu Corporation) • Detector: Conductivity Meter RF-20A XS (Shimadzu Corporation) • Column: Wakosil 5NH2, φ4.6mm×150mm (Fujifilm and Hikari Pharmaceutical Co., Ltd.) • Column Temperature: 25℃ • Mobile Phase: Solution containing 75 parts by mass of acetonitrile and 25 parts by mass of water • Flow Rate: 1 mL/min • Injection Volume: 2 μL • Excitation Wavelength: 320 nm • Measurement Wavelength: 430 nm • Post-column Conditions: The reaction was conducted at a reaction temperature of 150℃, with the reaction solution being an aqueous solution of 3% boric acid containing 1% by mass of L-arginine, a flow rate of 0.7 mL/min, and a reaction volume of 1% by mass of L-arginine.

1-2. Determination of Total Glucose Content (Amount of Glucose After Hydrolysis): Add 4 mL of 72% (w/w) sulfuric acid aqueous solution to 0.6 g of finely chopped bread and stir at 20°C for 1 hour. Then, add exchanged water to bring the sulfuric acid concentration to 4% (w/w) and heat in an autoclave at 121°C for 1 hour. After cooling, neutralize with sodium hydroxide to pH 7. Weigh 200 mL of the neutralized solution and filter it through filter paper. Dilute the filtrate 25 times with exchanged water and filter using a 0.45 μm membrane filter. Determine the glucose content by high-performance liquid chromatography (HPLC) under the following conditions. Taking into account the amount of glucose measured, the mass of the sample, and the dilution ratio during measurement, the total glucose content per 1g of dry bread was determined. (HPLC Conditions) • Analytical Apparatus: LC-20AD (Shimadzu Corporation) • Detector: Conductivity Meter RF-20A XS (Shimadzu Corporation) • Column: TSKgel Sugar AXI, φ4.6mm×150mm (Tosoh Corporation) • Column Temperature: 60℃ • Mobile Phase: 0.5mol/L boric acid buffer at pH 8.7 • Flow Rate: 0.4mL/min • Injection Volume: 20μL • Excitation Wavelength: 320nm • Measurement Wavelength: 430nm • Post-Column Conditions: The reaction was conducted at a reaction temperature of 150℃, with the reaction solution being an aqueous solution containing 1% L-arginine by mass.

1-3. Determination of Starch Content: 0.3g of bread was used as the test sample and placed in a 250mL glass centrifuge tube. 40mL of 50% ethanol aqueous solution was then added, and the mixture was stirred and allowed to stand (extraction of low molecular weight sugars). Next, the supernatant was filtered using glass fiber filter paper (ADVANTEC GS-25, Toyo Filter Paper Co., Ltd.) to remove the low molecular weight sugars (removal of low molecular weight sugars). This extraction and removal process was repeated until all low molecular weight sugars were completely removed. Complete removal of low molecular weight sugars was confirmed by the phenol-sulfuric acid method. In this method, 1mL of filtrate, 1mL of 5w/v% phenol aqueous solution, and 5mL of concentrated sulfuric acid were added to the test tube and mixed. The presence or absence of low molecular weight sugars was confirmed by observing the color development.

Next, the residue after extracting the low-molecular-weight sugars was transferred to a 250 mL glass centrifuge tube, and then 20 mL of ion-exchanged water and 2 mL of a 10% (w/w) sodium hydroxide aqueous solution were added and heated for 5 minutes to gelatinize the residue. Then, the residue was neutralized using hydrochloric acid and sodium hydroxide to achieve a pH of 7. Next, 10 mL of a glucoamylase solution (a solution containing 1.5 g of aspergillosis niger (manufactured by Megazyme Corporation) dissolved in 0.1 mol/L acetic acid buffer (pH 4.8) to a final volume of 100 mL) was added, and the reaction was carried out at 37°C for 2 hours. The resulting solution was filtered using filter paper (ADVANTEC No. 5B, manufactured by Toyo Filter Paper Co., Ltd.). The obtained filtrate was diluted 10 times with ion-exchanged water, and the glucose content was determined using a glucose assay kit (Glucose CII-Test wako, manufactured by Fujifilm and Koshun Pharmaceutical Co., Ltd.). The starch content was calculated from the glucose content using the following formula. Taking into account the calculated starch content, the mass of the test sample, and the dilution ratio during the test, the starch content per 1g of dried bread was obtained. [Formula 2] Starch content (g) = Glucose content (g) × 0.9

1-4. Determination of the molecular weight distribution of sugars in bread: 0.05 g of finely chopped bread was mixed with 10 mL of 0.1 mol/L sodium nitrate solution and allowed to stand overnight at room temperature. The mixture was then filtered through a 0.45 μm membrane filter. The resulting filtrate was subjected to HPLC using a screening column of the specified size under the following conditions. The results were analyzed using the GPC program on the SYSTEM INSTRUMENTS 480II data station. Furthermore, the molecular weight of each peak was estimated using calibration curves based on the dissolution time and molecular weight of molecular standards. Molecular standards were prepared using polytriglucose standards with known molecular weights (Shodex standard P-82 P-800, P-400, P-200, P-50, P-20, and P-5; manufactured by Showa Denko Corporation) and maltotriose. (HPLC conditions) • Analytical apparatus: Shodex GPC-101 (manufactured by Showa Denko Corporation) • Detector: Differential refractometer RI-71S (manufactured by Showa Denko Corporation) • Column: Two connected TSKgel GMPW XL tubes, φ7.8mm×300mm (manufactured by Tosoh Corporation) • Column temperature: 40℃ • Mobile phase: 0.1mol/L sodium nitrate solution • Flow rate: 1mL/min • Injection volume: 100μL

2. Evaluation Results Table 11 shows the results of the determination of the contents of free glucose, free maltose, total glucose (glucose after hydrolysis), and starch. In the breads of Examples 1-1 and 1-2, it was determined that compared to the breads of Comparative Examples 1-2, there was a tendency for higher amounts of free maltose and free glucose, and lower starch content.

Tables 12 and 13 show the results of the determination of the molecular weight distribution of sugars. In the breads of Comparative Examples 1-2, 3, 4-1, 4-2, 5-1, 5-2 and Reference Examples 3-1 to 3-3, the proportion of sugars with a molecular weight of less than 1,000 to 3,000 was less than 23%, and the proportion of sugars with a molecular weight of less than 1,000 was more than 57%. In contrast, in the breads of Examples 1-1, 1-2, 2-1, 3-2, 3-3, 4-1 and 4-2, the proportion of sugars with a molecular weight of 1,000 to 3,000 was less than 23%, and the proportion of sugars with a molecular weight of less than 1,000 was more than 57%. In other words, in the breads of Examples 1-1, 1-2, 2-1, 3-2, 3-3, 4-1, and 4-2, it is presumed that the α-amylase added to the dough lowers the molecular weight of sugars with a molecular weight of 1,000 to 3,000, thereby increasing the proportion of sugars with a molecular weight below 1,000. This improves various aromas such as sourness, rancidity, bran-like odor, bean curd odor, and bean odor. Therefore, it is understood that in breads with a protein content of 30% by weight or more and containing acetic acid, the improvement of sourness and rancidity is effective when the proportion of sugars with a molecular weight of 1,000 to 3,000 is below 23% and the proportion of sugars with a molecular weight below 1,000 is above 57%. Furthermore, it was learned that, under the condition of satisfying such a molecular weight distribution of sugars, it is also effective in improving the smell of wheat bran, soybean residue, or soybeans.

[Table 11]

[Table 12]

[Table 13]

Claims (6)

A type of bread is obtained from a pre-fermented dough containing at least 30% by weight of protein, acetic acid, and amylase per dry weight of the pre-fermented dough. The bread described in claim 1, wherein the aforementioned pre-fermented dough contains whole wheat flour and/or soy flour. The bread described in claim 1 or 2, wherein the aforementioned amylase is α-amylase. A bread mix for making pre-fermented dough, containing more than 30% by weight of protein, acetic acid, and amylase. A method for manufacturing bread includes: a step of preparing a pre-fermented dough by adding water to bread flour as described in claim 4; and a step of fermenting and baking the pre-fermented dough obtained in the aforementioned step. A type of bread is obtained from a pre-fermented dough containing at least 30% by mass of protein and acetic acid per dry mass of pre-fermented dough; In the molecular weight distribution of sugars determined under the following determination conditions, the proportion of sugars with a molecular weight of 1,000 or more but less than 3,000 relative to the total amount of sugars is less than 23%, and the proportion of sugars with a molecular weight of less than 1,000 is more than 57%; Determination conditions for the molecular weight distribution of sugars: (1) Finely cut 0.05g of bread and add 10mL of 0.1mol/L sodium nitrate solution, and after standing at room temperature overnight, filter using a membrane filter; (2) The obtained filtrate was subjected to HPLC using a screening column of the appropriate size to obtain a chromatogram; the molecular weight of each peak was obtained by using a calibration curve prepared using polytriglucose and maltotriose with known molecular weights as standards; (3) The peak area with a molecular weight of 1,000 or higher but less than 3,000 relative to the full peak area was calculated as the ratio of sugars with a molecular weight of 1,000 or higher but less than 3,000 relative to the total amount of sugars; and the peak area with a molecular weight of less than 1,000 relative to the full peak area was calculated as the ratio of sugars with a molecular weight of less than 1,000 relative to the total amount of sugars.