Composition for grain flour dough

Abstract

The objective of this invention is to provide a method for utilizing the residue remaining after useful oils have been extracted from microalgae, thereby reducing the burden on the global environment caused by residue disposal. [Solution] When the aqueous fraction of the residue remaining after oil has been extracted from microalgae is kneaded into flour dough and baked, steamed, or deep-fried, and then frozen and thawed, deformation such as syneresis and hardening can be suppressed. Therefore, this residue can be usefully utilized for the long-term preservation of flour-containing foods such as bread and noodles, and for suppressing deterioration of texture and taste due to freezing and thawing. Specifically, by using the aqueous fraction of the defatted residue of microalgae in an amount of 0.2 to 4.5 parts by mass in terms of solid content per 100 parts by mass of the raw material flour, it is possible to suppress the long-term preservation of flour-containing foods and the deterioration of texture and taste due to freezing and thawing. In other words, the residue after defatting of microalgae can be usefully utilized, and the above problem is solved.

Description

Technical Field

[0001] The present invention relates to a composition for grain flour-containing foods using a residue after oil phase separation of algae, a grain flour-containing food comprising the same, and a method for producing the same.

Background Art

[0002] In recent years, algae biomass has attracted attention. Since microalgae produce oil during the process of photosynthesis, attempts have been made to utilize this oil as fuel. Microalgae have lower carbon dioxide emissions than carbon dioxide absorption during growth, and the land area and water volume required for their growth are far smaller than those of common plants, so they contribute to the suppression of global warming, and their market size is said to reach as high as 2,200 trillion yen. However, there is a problem of disposal of the residue after extracting useful oil from microalgae. If a method for utilizing the residue is established, not only will the market price of oil decrease and its utilization be promoted, but it will also contribute to the reduction of environmental load.

[0003] Accordingly, as useful components other than oil, methods have been proposed that focus on starch produced by microalgae, and utilize the starch by saccharification (Patent Document 1) or fermentation (Patent Document 2).

[0004] However, the particle size of the starch produced by microalgae is extremely fine and difficult to isolate, and its production energy cost is high, so the industrial utilization of the starch itself has been delayed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of Invention

Problems to be Solved by the Invention

[0006] The objective of this invention is to reduce the burden on the global environment caused by residue disposal by proposing a method for utilizing the residue remaining after useful oils have been extracted from microalgae, and in particular, a method for utilizing the aqueous fraction of that residue. [Means for solving the problem]

[0007] In order to solve these problems, the inventors conducted various studies and found that the aqueous phase fraction of the residue remaining after extracting oil from microalgae can suppress the denaturation of grain flour-containing foods such as bread and noodles during freezing and thawing, thus completing the present invention.

[0008] In other words, the present invention was completed based on the above findings and consists of the following [1] to

[14] . [1] A food product containing grain flour, comprising 0.2 to 4.5 parts by mass of the aqueous fraction of defatted residue of microalgae, on a solid content basis, per 100 parts by mass of grain flour. [2] The grain flour-containing food according to [1], wherein the microalgae are one or more from the genera Chlamydomonas and Botryococcus. [3] The grain flour-containing food according to [1], wherein the microalgae are one or more of Chlamydomonas reinhardtii and Botryococcus bra4unii. [4] A grain flour-containing food according to any of [1] to [3] above, wherein the defatted residue contains less than 30% protein and less than 70% carbohydrates in its solid content. [5] A flour-containing food from any of the above [1] to [3], wherein the flour-based food is a bakery item or a noodle item. [6] A method for producing a food containing cereal flour, comprising adding an aqueous fraction of defatted residue of microalgae to 100 parts by mass of cereal flour in an amount of 0.2 to 4.5 parts by mass on a solid basis. [7] A method for producing the grain flour-containing food according to [6], wherein the microalgae are one or more from the genera Chlamydomonas and Botryococcus. [8] A method for producing the grain flour-containing food according to [6], wherein the microalgae are one or more of Chlamydomonas reinhardtii and Botryococcus braunii. [9] A composition for grain flour-containing food comprising defatted residue of microalgae, wherein the protein content of the solids of the defatted residue is less than 30% and the carbohydrate content is less than 70%.

[10] The grain flour-containing food composition according to [9], wherein the microalgae are one or more from the genera Chlamydomonas and Botryococcus.

[11] The grain flour-containing food composition according to [9], wherein the microalgae are one or more of Chlamydomonas reinhardtii and Botryococcus braunii.

[12] A method for improving the texture of a grain flour-containing food, comprising adding an aqueous fraction of defatted residue of microalgae to 100 parts by mass of grain flour in an amount of 0.2 to 4.5 parts by mass in terms of solid matter.

[13] A method for improving the texture of the grain flour-containing food according to

[12] , wherein the microalgae are one or more from the genera Chlamydomonas and Botryococcus.

[14] A method for improving the texture of the flour-containing food according to

[12] , wherein the microalgae are one or more of Chlamydomonas reinhardtii and Botryococcus braunii. [Effects of the Invention]

[0009] According to the present invention, the texture of grain flour-containing foods such as bread and noodles can be improved, and in particular, texture improvement can be achieved by suppressing denaturation during freezing and thawing. Furthermore, since the present invention provides a useful method for utilizing the defatted residue of microalgae, it is expected to contribute to reducing the environmental burden caused by residue disposal. [Brief explanation of the drawing]

[0010] [Figure 1] This shows the fractionation procedure (in the case of alkaline treatment) for the aqueous phase fraction of microalgae (Chlamydomonas genus, which produces and accumulates lipids within its cells). [Figure 2] This shows the fractionation procedure (in the case of acid treatment) for the aqueous phase fraction of microalgae (Chlamydomonas genus, which produces and accumulates lipids within its cells). [Modes for carrying out the invention]

[0011] The first aspect of the present invention is a grain flour-containing food containing the aqueous phase fraction of defatted residue of microalgae, and the second aspect is a method for producing a grain flour-containing food using the aqueous phase fraction. Furthermore, the third aspect of the present invention is a composition for a grain flour-containing food containing the aforementioned aqueous phase fraction as an active ingredient, and the fourth aspect is a method for improving the texture of a grain flour-containing food by adding the aqueous phase fraction. These inventions will be described in detail below with reference to examples and other information.

[0012] The "microalgae" used in this invention are also called phytoplankton and are algae with a size of 1 mm to 1 μm. Microalgae can be classified into groups such as diatoms, cyanobacteria, green algae, and red algae based on their morphology and intracellular photosynthetic pigments. The microalgae used in this invention may be one of these groups used alone or in combination of two or more, but it is particularly preferable to use one or more microalgae belonging to the green algae group. The genera of green algae include Botryococcus, Chlamydomonas, Euglena, Chlorella, and Dunaliella, but the microalgae used in this invention are preferably one or more microalgae belonging to the Botryococcus, Chlamydomonas, and Chlamydomonas genera, and more preferably one or more microalgae belonging to the Botryococcus and Chlamydomonas genera. Among the microalgae belonging to the genus Botryococcus, Botryococcus braunii is preferred, and among the microalgae belonging to the genus Chlamydomonas, Chlamydomonas reinhardtii is preferred.

[0013] In this invention, the "defatted residue" of microalgae refers to the residue remaining after the oil (fats and greases) removal operation from microalgae, which has been degreased until the lipid content in its solid matter is preferably less than 15%, more preferably less than 12%, and even more preferably less than 10%. The method for removing lipids from microalgae is not particularly limited; for example, methods such as hot water extraction or solvent extraction such as hexane can be used. However, if fats and greases are produced and accumulated within the cells of microalgae, it is necessary to perform cell disruption treatment with acid or alkali before carrying out the degreasing operation (see, for example, Figure 1).

[0014] The "aqueous phase fraction" of the defatted residue of microalgae used in the present invention refers to the water-soluble fraction after removing water-insoluble solids from the defatted residue of microalgae, and can be separated as the supernatant or supernatant from the crushed material after the defatting treatment using a centrifuge or the like. The majority of the aqueous phase fraction is water, and if cell disruption treatment with alkali is performed, it contains salt (ash) produced by the neutralization treatment, as well as some lipids that are not completely removed even after the defatting operation, and proteins and carbohydrates. The lipid content in the solid content of the aqueous phase fraction is less than 15%, preferably less than 10%, more preferably less than 5%, and even more preferably less than 3%, the protein content is less than 30%, preferably less than 25%, more preferably less than 20%, and even more preferably less than 15%, and the carbohydrate content is less than 70%, preferably less than 50%, more preferably less than 25%, and even more preferably less than 20%. The protein values ​​used here are calculated by multiplying the amount of nitrogen quantified using the Kjeldahl method by a nitrogen-to-protein conversion factor of 6.25. The "aqueous phase fraction" can be used after further increasing its solid content by removing moisture through processes such as spray drying or freeze drying. From the viewpoint of preservation and ease of handling, it is preferable that it contains at least 5% solid content, preferably 10% or more, more preferably 30% or more, even more preferably 50% or more, and most preferably 80% or more.

[0015] The "grain flour" used in the present invention refers to all powdery raw materials derived from cereals, for example, grain flours such as wheat flour (strong flour, all-purpose flour, weak flour), rye flour, rice flour, tapioca flour, barley flour, corn flour, buckwheat flour, soybean flour, potato flour, and millet flour, as well as starches derived from grain flours, and powdery raw materials obtained by subjecting any of these to one or more treatments including physical treatments such as pulverization, defatting, bleaching, pregelatinization, enzymatic decomposition, and alkali decomposition, chemical treatments such as etherification, esterification, and crosslinking, and classification treatments. The "grain flour" referred to in the present invention is not limited to one of these, and may be any combination of two or more thereof.

[0016] The "grain flour-containing food" referred to in the present invention refers to a food containing the above-mentioned grain flour, and preferably refers to a batter dough or dough prepared by mixing the above-mentioned grain flour with a liquid raw material such as water, or a food obtained by subjecting these as-is or through filling with fillings and the like to heat treatments such as baking, steaming, and frying. Specific examples include bakery doughs such as bread, donuts, cookies, pies, sponge cakes, butter cakes, and hotcakes, and bakery products obtained by baking or the like thereof; doughs for Japanese confectioneries such as steamed bread, steamed buns, dorayaki, and castella, and Japanese confectioneries obtained by baking or the like thereof; noodles such as udon, soba, Chinese noodles, and pasta; and dim sum doughs such as gyoza, shaomai, wonton, and spring rolls, and side dishes obtained by baking or the like thereof.

[0017] As described above, a first aspect of the present invention is a grain flour-containing food comprising the aqueous phase fraction of the defatted residue of the aforementioned microalgae. By including the aqueous phase fraction of the defatted residue of the aforementioned microalgae as part of the raw material, the grain flour-containing food not only has a favorable texture immediately after preparation, but also has suppressed texture deterioration caused by temperature changes such as freezing and thawing, as well as long-term storage. The texture referred to herein means the characteristic texture unique to each grain flour-containing food, for example, the fluffy softness and elasticity for bread, and the smoothness and firm elasticity for noodles. The details of its evaluation method vary depending on each food, but evaluation can be performed by sensory evaluation by humans, measured values with a rheometer, and the like. The content of the aqueous phase fraction in the grain flour-containing food is not particularly limited, but it is preferred to be included in a range of 0.1 to 4.8 parts by mass, preferably 0.2 to 4.5 parts by mass, and more preferably 0.25 to 3 parts by mass in terms of solid content relative to 100 parts by mass of the grain flour.

[0018] As described above, a second aspect of the present invention is a method for producing a grain flour-containing food comprising the aqueous phase fraction of the defatted residue of the aforementioned microalgae. As part of the raw material of the grain flour-containing food, the aqueous phase fraction of the defatted residue of the aforementioned microalgae is preferably added in an amount of 0.1 to 4.8 parts by mass, preferably 0.2 to 4.5 parts by mass, and more preferably 0.25 to 3 parts by mass in terms of solid content relative to 100 parts by mass of the grain flour. When the aqueous phase fraction is used as a powder that has undergone spray drying or the like, it can be used by mixing with other powdery raw materials, but when used in a state with high moisture content, it may be adjusted, added, or the like so as to follow the same formulation and production procedures as liquid raw materials such as water used in the general formulation and production procedures for each food. In general, since grain flour-containing foods contain a large amount of starchy substances, they are prone to denaturation through retrogradation, decomposition and the like due to refrigeration, freezing, strong stirring, high-temperature heating and the like. According to the production method of the present invention, it is possible to provide a grain flour-containing food in which texture deterioration caused by this starchy substance is suppressed.

[0019] A third aspect of the present invention is a food composition for grain flour containing the aqueous phase fraction of the defatted residue of the microalgae described above, as an active ingredient. When a composition containing this aqueous phase fraction as an active ingredient is added during the production of grain flour containing food, it exhibits the effect of suppressing deterioration over time during storage and deterioration during freezing and thawing of the food, and can therefore be effectively utilized as a composition for improving the texture of such grain flour containing food. The approximate content of each component in the solid content of the aqueous fraction is as described above: lipids are less than 15%, preferably less than 10%, more preferably less than 5%, and even more preferably less than 3%; proteins are less than 30%, preferably less than 25%, preferably less than 20%, and even more preferably less than 15% (calculated by multiplying the amount of nitrogen quantified by the Kjeldahl method by the "nitrogen-protein conversion factor of 6.25"); and carbohydrates are less than 70%, preferably less than 50%, more preferably less than 25%, and even more preferably less than 20%. In the grain flour-containing food composition of the present invention, the content of the aqueous phase fraction should preferably be at least 5% as solid content, more preferably 10% or more, more preferably 30% or more, even more preferably 50% or more, and most preferably 80% or more, from the viewpoint of ease of handling during the production of each food product. The adjustment of the solid content can be performed by removing moisture from the aqueous phase fraction immediately after the degreasing and solid phase removal operations of the microalgae by spray drying or freeze drying.

[0020] A fourth aspect of the present invention is a method for suppressing deterioration of the texture of a grain flour-containing food by adding the aqueous fraction of the defatted residue of the microalgae described above. If the grain flour-containing food is manufactured by adding the aqueous fraction of the defatted residue of the microalgae described above as part of the raw materials, in an amount of 0.1 to 4.8 parts by mass, preferably 0.2 to 4.5 parts by mass, and more preferably 0.25 to 3 parts by mass in terms of solid content, per 100 parts by mass of grain flour, deterioration over time during storage and deterioration during freezing and thawing can be suppressed.

[0021] The present invention will be described in detail with reference to the following embodiments, but it is not limited to these embodiments. Also, "mass%" may sometimes be simply represented as "%". [Examples]

[0022] (Preparation of the aqueous fraction of Chlamydomonas (alkaline treatment)) Chlamydomonas (Chlamydomonas reinhardtii, a member of the Chlamydomonas genus, Chlorophyta, obtained from the Chlamydomonas Resource Center (USA)) was inoculated into BG-11 medium (Sigma-Aldrich, cyanobacteria BG-11 freshwater aqueous solution) and pre-cultured. This was then cultured in a bag-type photobioreactor (Chitose Research Institute Co., Ltd., 100-liter medium) at 25-33°C for approximately 4 days, and approximately 2700g (approximately 90% water content) of "live Chlamydomonas" was recovered by centrifugation. Next, the live Chlamydomonas was subjected to alkaline hydrolysis (addition of 1647g of 6M NaOH, heating at 95°C for 3 hours), neutralization (addition of 939g of 10M HCl to adjust the pH to 4.0), and then 3537g of hexane was added to extract the lipid fraction (gentle shaking at 40°C for 90 minutes). To fractionate the mixture into three phases—hexane phase, solid phase, and aqueous phase—centrifugation (14,000 rpm, 10 minutes) was performed first. The upper hexane phase was collected with a pipette, the aqueous phase was collected by decantation, and the remaining solid phase was scraped off with a silicone spatula to obtain all three fractions. The component analysis values ​​of the obtained aqueous and solid phases are shown in Table 1 below, and their solid content equivalents are shown in Table 2. Note that the aqueous phase contains almost no hexane, but the solid phase contains a small amount of hexane. Furthermore, the "live Chlamydomonas" used in the following tests is Chlamydomonas algae that have been washed with 0.1% copper sulfate solution and then centrifuged (approximately 90% moisture content).

[0023] (Preparation of Botryococcus (as defatted residue)) For Botryococcus (Botryococcus braunii, a member of the genus Botryococcus in the class Chlorophyceae, obtained from Chitose Research Institute Co., Ltd.), the thallus was dried at 50°C for 24 hours, followed by hexane extraction to obtain a defatted residue (moisture content less than 1%). Since Botryococcus produces lipids extracellularly, alkaline cell disruption treatment is unnecessary, and the resulting defatted residue corresponds to the combined fraction of the aqueous and solid phase fractions of Chlamydomonas.

[0024] [Table 1]

[0025] [Table 2]

[0026] (Drying of each fraction of Chlamydomonas) [SD] Using a Yamato Corporation small spray dryer (ADL311), samples with concentrations (Bx) of 10-15 were spray-dried at a pump flow rate of 600 ml / h and an outlet temperature of 90°C. [FD] Using a small freeze-dryer (RLEII-206) manufactured by Kyowa Vacuum Technology Co., Ltd., each sample fraction was placed in a tray to a density of 10 kg / m2 and pre-frozen, then dried under a vacuum of 4 Pa ​​or less for 24 hours. In the table or text, "post-heated FD product" indicates that a heating process (80°C, 10 minutes) was performed before freeze-drying.

[0027] (Bread preparation) The mixing blade was attached to the baking pan of a home bread maker (Iris Ohyama, IBM-020-B). Following the recipe shown later, water was added, followed by a premix of flour and other powdered ingredients (including dry yeast). The "Baking Menu 1" (white bread) and "1 loaf" were selected and the machine was started to bake the bread. The finished bread was removed from the pan, wrapped in sandwich paper, and left at room temperature (approximately 25°C) for 2 hours. The volume was then measured, and a portion of the bread, sliced ​​to a thickness of 2.5 cm, was set aside for rheometer measurement and sensory evaluation. The remainder was placed in a polyethylene bag and frozen for 2 days. The frozen sliced ​​bread was thawed by leaving it in the refrigerator for 24 hours, and then rheometer measurement and sensory evaluation were performed.

[0028] (Measuring the volume of bread) Freshly baked bread, removed from a bread maker, was wrapped in commercially available sandwich sheets (pulp paper) and left at room temperature for two hours. This was then placed in a polyethylene bag about 0.01 mm thick, and submerged in a 10L pot filled with water, just above the liquid level. The volume of the overflowing water was measured and considered to be the volume of the bread.

[0029] (Measuring the hardness of bread using a rheometer) Using the "IMADA Rheometer," measurements were taken under the condition of "bread hardness" (measuring a displacement of 2 mm / s and 5 mm N). Five measurements were taken at approximately 2 cm from the edge of the bread cross-section, and the average value was defined as the "hardness."

[0030] (evaluation) 1. Evaluation of the physical properties of bread The "physical property evaluation" of the bread was performed based on the volume and hardness measurements described above. The evaluation criteria are shown in Table 3. 2. Sensory evaluation of bread The "sensory evaluation" of the bread focused on taste and texture. Specifically, three panelists agreed on a scoring system (compared to a control group, with a rating of 4 points for excellent, 3 points for good, 2 points for average, and 1 point for poor). Note that the sensory evaluation results for taste and texture before freezing are not included in the table.

[0031] [Table 3]

[0032] Table 4 shows the ingredients of the bread dough, its analytical values, and the results of the sensory evaluation.

[0033] [Table 4]

[0034] Bread with live Chlamydomonas added (Test Group 1) rose less than bread without Chlamydomonas (Control Group) and became hard after freezing and thawing. Similarly, bread with the solid phase fraction of Chlamydomonas added (Test Group 8) rose less than bread without Chlamydomonas (Control Group) and became hard after freezing and thawing. On the other hand, among the breads to which the aqueous phase fraction of Chlamydomonas was added in solid content terms ranging from 0.29 to 4.78 parts by mass per 100 parts by mass of wheat flour, the breads with 0.29 parts by mass (Test Group 2), 0.59 parts by mass (Test Group 3), 1.17 parts by mass (Test Group 4), 2.34 parts by mass (Test Group 5), and 3.58 parts by mass (Test Group 6) added rose better than bread without Chlamydomonas (Control Group) and did not become as hard as the control group bread after freezing and thawing.

[0035] Next, we decided to investigate the effects of adding heat-treated live Chlamydomonas, dried aqueous fraction of Chlamydomonas (freezed and unsteamed after heating), Botryococcus (defatted residue), as well as commercially available sterilized spirulina powder (DIC Corporation, "Spirulina Powder ET-F"), Chlorella hot water extract (Chlorella Industries Co., Ltd., "Flebotide Sugar Solution 241A"), trehalose, and maltose during bread baking and freezing / thawing. The bread preparation and evaluation methods were the same as described above, and the bread dough composition and evaluation results are shown in Table 5 below.

[0036] [Table 5]

[0037] When trehalose (test group 14) or maltose (test group 15), which are sugars said to be effective in improving bread rise and freeze-thaw resistance, were added, a certain effect was confirmed: the bread rose better and remained less hard after freezing and thawing compared to the control group without any additives. Similar effects were also confirmed with commercially available spirulina powder (test group 12), but while chlorella hot water extract was slightly better than the control group, it did not show the same effect as the aforementioned sugars (test group 13). Furthermore, in order to investigate whether the heat treatment process of the sample affects this effect, bread baking tests were conducted on heated raw Chlamydomonas (test section 9), freeze-dried Chlamydomonas aqueous phase after heating (test section 10), and Chlamydomonas aqueous phase heated and dried by spray drying (test section 11). The results showed that heating raw Chlamydomonas did not affect the impartment or enhancement of this effect (test section 9), and the freeze-dried (test section 10) and spray-dried (test section 11) Chlamydomonas aqueous phase fractions after heating showed only the same effect as the Chlamydomonas aqueous phase fraction that had not undergone the drying process (test section 5 in the previous test). In addition, when the defatted residue of Botryococcus (corresponding to a combined fraction of the Chlamydomonas aqueous and solid phase fractions) was examined (test section 16), the same effect as the Chlamydomonas aqueous phase addition section (test section 10) was observed. Based on the above, it was concluded that rather than the heating process for the sample affecting this effect, the addition of the solid phase fraction negatively impacts this effect (test section 8 in the previous test). However, if a certain amount or more of the fraction equivalent to the aqueous phase fraction is included (for example, 0.2% or more relative to the flour), it is thought to be effective in improving the rise and freeze-thaw resistance of bread.

[0038] (Preparing udon noodles) Next, to examine the effects of the present invention on udon noodles, udon noodles were prepared according to the procedure in Table 6 and the formulation in Table 7 below. Hardness measurements (rheometer) and evaluations of appearance and sensory characteristics (texture (chewiness and taste)) were performed before and after freezing and thawing. The evaluation items and criteria for appearance and sensory characteristics are shown in Table 8, and the results are shown in Table 7.

[0039] [Table 6]

[0040] [Table 7]

[0041] [Table 8]

[0042] Udon noodles to which the aqueous fraction of Chlamydomonas was added as solid content at a rate of 0.59 to 3.51 parts per 10

[0043] Next, we investigated whether the same effect would be achieved if the aqueous fraction of Chlamydomonas was obtained by acid treatment instead of alkaline treatment. First, aqueous and solid (freeze-dried (FD)) fractional samples of Chlamydomonas were prepared using the acid treatment procedure shown in Figure 2, and bread was prepared and evaluated using these samples in the same manner as described above. The nutritional components and their solid content equivalents for each fraction of the aqueous and solid phases of Chlamydomonas are shown in Tables 9 and 10, respectively, and the bread formulation and evaluation results are shown in Table 11.

[0044] [Table 9]

[0045] [Table 10]

[0046] [Table 11]

[0047] Adding the Chlamydomonas aqueous fraction at a concentration of less than 5.7% of the flour showed positive effects on bread leavening and freeze-thaw resistance, as well as improved texture. It was also found that a protein content (solids) of less than 30% in the aqueous fraction was preferable.

Claims

1. A food product containing grain flour, comprising 0.2 to 4.5 parts by mass of the aqueous fraction of defatted residue of microalgae, calculated on a solid content basis, per 100 parts by mass of grain flour.

2. The grain flour-containing food according to claim 1, wherein the microalgae are one or more from the genera Chlamydomonas and Botryococcus.

3. The grain flour-containing food according to claim 1, wherein the microalgae is one or more of Chlamydomonas reinhardtii and Botryococcus braunii.

4. The cereal flour-containing food according to any one of claims 1 to 3, wherein the defatted residue contains less than 30% protein and less than 70% carbohydrates in its solid content.

5. The grain flour-containing food according to any one of claims 1 to 3, wherein the grain flour food is bakery products or noodles.

6. A method for producing a food product containing cereal flour, comprising adding an aqueous fraction of defatted residue of microalgae to 100 parts by mass of cereal flour in an amount of 0.2 to 4.5 parts by mass in terms of solid matter.

7. A method for producing a grain flour-containing food according to claim 6, wherein the microalgae are one or more from the genera Chlamydomonas and Botryococcus.

8. A method for producing a grain flour-containing food according to claim 6, wherein the microalgae is one or more of Chlamydomonas reinhardtii and Botryococcus braunii.

9. A composition for grain flour-containing food products comprising defatted residue of microalgae, wherein the protein content in the solid content of the defatted residue is less than 30% and the carbohydrate content is less than 70%.

10. The grain flour-containing food composition according to claim 9, wherein the microalgae are one or more from the genera Chlamydomonas and Botryococcus.

11. The grain flour-containing food composition according to claim 9, wherein the microalgae is one or more of Chlamydomonas reinhardtii and Botryococcus braunii.

12. A method for improving the texture of a grain flour-containing food product, comprising adding an aqueous fraction of defatted residue of microalgae to 100 parts by mass of grain flour in an amount equivalent to 0.2 to 4.5 parts by mass of solid matter.

13. The method for improving the texture of a grain flour-containing food according to claim 12, wherein the microalgae are one or more from the genera Chlamydomonas and Botryococcus.

14. A method for improving the texture of a grain flour-containing food according to claim 12, wherein the microalgae is one or more of Chlamydomonas reinhardtii and Botryococcus braunii.

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