Method for producing heat-treated cereal flour

Abstract

This method for producing a heat-treated cereal flour has a step for using an extruder to mix water with a grain flour and heat and pressurize the result to produce a heat-treated cereal flour, wherein a cooling die is attached to an outlet for the heat-treated product in the extruder. In the cooling die, the opening area of an outlet opening section that opens toward the extrusion direction of the extruder is preferably 20 mm2 or greater, and the total length of the cooling die in the extrusion direction of the extruder is preferably 60 mm or greater. The extruder is preferably a twin-screw extruder.

Description

Manufacturing method of heat-treated grain flour

[0001] The present invention relates to a method for producing heat-treated flour, heat-treated flour, foods using heat-treated flour, and a method for improving the aging resistance of foods using heat-treated flour.

[0002] Patent Document 1 describes a method for producing a mix for bakery products or skins, in which raw wheat flour is added with only 40 to 45% water, and then subjected to moist heat treatment by pressurizing and heating using a single-screw extruder to obtain moist heat-treated wheat flour having a degree of gelatinization of 85% or more and a viscosity of 500 B.U. or less, and this moist heat-treated wheat flour is added in an amount of 1 to 30% by weight to the wheat flour used in the mix. Patent Document 2 describes a method for producing meat-like foods using a cooling die.

[0003] JP 2003-061600 A US 2019 / 0364925 A1

[0004] However, the prior art described in Patent Document 1 was not sufficient in terms of producing heat-treated cereal flour that can impart a good texture and resistance to deterioration of texture over time to foods. Furthermore, Patent Document 2 relates to meat-like foods, and does not consider at all how to improve the effect of heat-treated cereal flour in imparting a good texture and resistance to deterioration of texture over time to foods.

[0005] The present inventors have conducted extensive research into methods for producing novel cereal flour ingredients that use an extruder and have the effect of imparting excellent texture and resistance to deterioration over time, and have found that by attaching a cooling die to an extruder, it is possible to obtain heat-treated cereal flours that can impart excellent texture and resistance to deterioration over time to foods.

[0006] The present invention is based on the above findings and provides a method for producing heat-treated grain flour, which comprises a step of mixing grain flour with water using an extruder and heating and pressurizing the mixture to produce heat-treated grain flour, and a cooling die is attached to the outlet of the extruder.

[0007] The present invention also provides heat-treated flours produced by the above-mentioned production method, foods using the heat-treated flours, food compositions, and methods for improving the aging resistance of foods.

[0008] The present invention will be described below based on preferred embodiments. The upper and lower limits described in the present specification can be combined without any particular restrictions. Furthermore, in the present specification, the term "texture" includes a moist texture.

[0009] The present inventors have found that the following problems exist when attempting to obtain heat-treated flours by adding water during the heating and pressurizing step in an extruder. To obtain heat-treated flours that have a good texture and excellent resistance to deterioration over time, it is preferable to add a large amount of water during heat treatment in the extruder. On the other hand, it has been found that adding a large amount of water during heating and pressurizing in the extruder reduces the viscosity of the flour dispersion, which is a mixture of water and flour, at the extruder outlet, resulting in a decrease in pressure inside the extruder. It has also been found that adding a large amount of water during heating and pressurizing in the extruder reduces the viscosity of the water and flour mixture, causing the flour dispersion to spray out from the extruder outlet, making it impossible to stably produce heat-treated flours. Therefore, the present inventors attached a cooling die to the extruder outlet and increased the pressure inside the extruder. As a result, the inventors succeeded in producing heat-treated flour that can stably discharge flour from the extruder outlet, ensures production stability, and has the effect of imparting excellent texture to foods and imparting resistance to texture deterioration over time. Furthermore, the inventors discovered that even when the water content is relatively low (for example, when it is lower than 46% by mass of the flour), excellent texture and resistance to deterioration can be improved by attaching a cooling die.

[0010] As described above, the present invention enables the pressure inside the extruder to be increased by attaching a cooling die to the extruder outlet. This facilitates the opening of the side chains of starch in cereal flours, thereby maintaining production stability and providing excellent texture and resistance to texture deterioration over time. In this specification, a cooling die refers to a die that functions as a heat exchanger, capable of removing at least a portion of the heat from the contents passing through it. The heat exchanger function here does not necessarily need to be expressed as a difference between the temperature of the heat-treated material discharged from the cooling die and the temperature inside the extruder. A cooling die typically has a tubular or cylindrical shape, and by removing heat from the outer layer of the contents through the tube wall, it is possible to increase the viscosity of the outer layer and increase the pressure inside the extruder. Note that the term "cylindrical" in this specification refers to a cylindrical shape, a rectangular cylindrical shape, or a shape with a cavity formed inside as a flow path. Furthermore, a cooling die typically has a certain length or more and an opening area of ​​a certain amount or less relative to the extruder barrel. By attaching a die having such a shape to the outlet of an extruder, the pressure inside the extruder can be increased.

[0011] The extruder of the present disclosure typically comprises a hollow cylindrical barrel (also referred to as a cylinder) containing a raw material composition (in this disclosure, a cereal flour mixture (e.g., a mixture containing cereal flour and water)), a screw disposed inside the barrel and driven to rotate by a drive source such as a motor, a feeder that supplies the raw material composition into the barrel, and the cooling die attached to the outlet of the barrel; the raw material composition introduced into the barrel via the feeder moves towards the die while being compressed by the screw, and is extruded through the die. Note that a heating means such as a cartridge heater may be attached around the barrel so that the raw material composition inside the barrel can be heated.

[0012] The extruder used in the present invention may be either a single-screw extruder or a twin-screw extruder, but is preferably a twin-screw extruder. A twin-screw extruder is preferred. A twin-screw extruder has two screws arranged parallel to each other. When the extruder used in the present invention is a twin-screw extruder, the use of two screws provides high kneading power and excellent processing capacity, and the high propulsion force makes it easy to apply strong pressure to the material to be heat-treated (flour mixture) near the outlet of the barrel, which is preferred.

[0013] The cooling die is attached to the end of the extruder at the outlet of the material to be heat-treated (the outlet end of the barrel). The cooling die and the barrel of the extruder are airtightly connected, and their interiors are in communication. The cooling die has an inlet opening that opens in the opposite direction to the extrusion direction of the extruder, an outlet opening that opens in the extrusion direction of the extruder, and a flow path for the material to be heat-treated connecting the two openings. In the flow path, the material to be heat-treated flows along the extrusion direction of the extruder. The material to be heat-treated that has passed through the outlet of the extruder barrel is introduced into the flow path through the inlet opening of the cooling die and is extruded out of the cooling die from the outlet opening.

[0014] From the viewpoint of reducing the fluidity of the contents passing through, the cooling die preferably has a length in the extruder extrusion direction (hereinafter also referred to as "total length L" or "total length of the cooling die") of 60 mm or more. Having such a length is preferable in that the effect of increasing the internal pressure of the extruder by using a cooling die is enhanced, and the effects of improving the texture and improving resistance to texture deterioration over time, as well as excellent production stability, are excellent. From this viewpoint, the length of the cooling die in the extruder extrusion direction is preferably 100 mm or more, more preferably 200 mm or more. Furthermore, from the viewpoint of production stability, in which the heat-treated flour can be stably discharged, it is preferable that the length of the cooling die in the extruder extrusion direction is 1200 mm or less.

[0015] The opening area of ​​the outlet opening of the cooling die (hereinafter also referred to as the "opening area of ​​the cooling die" or "area S2") is 20 mm２ The above size is preferable in terms of the production stability of the heat-treated flour and the fact that clogging and the like are unlikely to occur at the outlet, allowing the contents to be discharged stably, and is also preferable in terms of the production stability of the heat-treated flour being able to be discharged stably from the cooling die without clogging and the like. From this point of view, the opening area of ​​the outlet opening of the cooling die is 23 mm ２ More preferably, it is 25 mm or more. ２ It is particularly preferable that the opening area of ​​the outlet opening of the cooling die is 550 mm or more. ２ It is preferable that the pressure applied to the material to be heat-treated (cereal flour mixture) in the barrel of the extruder or the cooling die is sufficiently increased, and the effect of improving the texture and the durability of the texture over time is high. ２ More preferably, it is 280 mm or less. ２ It is particularly preferred that:

[0016] Furthermore, the ratio of the area of ​​the outlet opening of the cooling die to the screw diameter of the twin-screw extruder (die opening area mm ２ It is preferable that the ratio (unit: mm):(die opening area mm) is equal to or less than a predetermined value, because increasing the pressure inside the extruder makes it easier to open the side chains of the starch in the cereal flour, thereby further improving the texture and resistance to deterioration of the texture over time. ２ ) / (extruder screw diameter mm)) is preferably 11.8 or less, more preferably 8.0 or less, and even more preferably 6.0 or less.

[0017] In addition, the above ratio (unit: mm): (die opening area mm ２ From the viewpoint of production stability, in which the thickened material to be heat-treated is stably extruded, the ratio (mm) / (screw diameter of extruder) is preferably 0.11 or more, more preferably 0.3 or more, and particularly preferably 0.5 or more.

[0018] The area of ​​the outlet opening of the cooling die is the area when the outlet opening of the cooling die is viewed from the opposite side to the extrusion direction of the extruder, and if there are multiple outlet openings of the cooling die that communicate with the outlet of the extruder, it is the total area of ​​the multiple openings.

[0019] Furthermore, the screw diameter of an extruder is the diameter of a circular projected image of the screw as viewed from its axial direction, and is the length of the longest line segment that intersects the projected image if the shape is other than circular. When the screw diameters of the two screws in a twin-screw extruder are different, the diameter is the diameter of the larger screw.

[0020] The cross-sectional shape of the cooling die along the extruder extrusion direction is not particularly limited. Furthermore, the area of ​​the cross section of the cooling die perpendicular to the extrusion direction may or may not be substantially constant along the extrusion direction. For example, in the flow path of the material to be heat-treated, which is made up of the inside of the extruder barrel and the cooling die, the ratio (S1:S2) of the maximum area of ​​the cross section perpendicular to the extruder extrusion direction (maximum area of ​​the flow path) S1 to the area S2 of the outlet opening of the cooling die is preferably in the range of 1:0.01 to 1.80. The maximum area of ​​the flow path is the maximum value over the entire length of the flow path in the extruder extrusion direction, and when the flow path is divided into multiple sections in the cross section, it is the sum of the areas of the multiple flow paths.

[0021] The cooling die used in the present invention functions as a heat exchanger. One example of a heat exchanger is a partition-type heat exchanger. For example, a heat exchanger may have a double-pipe structure consisting of an outer tube and an inner tube disposed inside the outer tube and functioning as a flow path for the contents of the cooling die. A refrigerant is disposed between the outer tube and the inner tube, and the contents of the inner tube are cooled by heat exchange with the refrigerant. It is preferable that the refrigerant is a fluid (liquid or gas) that flows through a flow path disposed between the outer tube and the inner tube. In addition to the partition-type heat exchanger, other examples of heat exchangers include direct contact types. For example, a heat exchanger may be used in which cold air is introduced into the cooling die to cool the contents.

[0022] The cooling method for the object to be heat-treated using the cooling die is not particularly limited, and may be a forced cooling method or a natural cooling method. The forced cooling method is a method that uses one or more refrigerants selected from liquids and gases, and cools the object to be heat-treated using the refrigerant as a fluid and a driving source to cause it to flow. The natural cooling method is a method that does not use the refrigerant or driving source, but simply introduces the object to be heat-treated into the flow path of the cooling die and passes it through, thereby allowing it to cool naturally.

[0023] For example, in a double-pipe structure, even when no refrigerant is flowing (natural cooling method), the air in the area exchanges heat with the object to be heat-treated in the same way as the refrigerant. Specifically, heat exchange occurs between the air present between the double-pipe structure and the contents in the inner pipe, and heat is removed from the contents in the inner pipe. This removes heat from the object to be heat-treated, thereby enabling a certain increase in pressure on the object to be heat-treated. In Examples 22 and 24 to 27 described below, the object to be heated is cooled and its temperature is reduced even without circulating a refrigerant in the double-ring structure. Furthermore, Examples 13 to 15 described below demonstrate that the pressure inside the extruder can be sufficiently increased even without circulating a refrigerant in the double-ring structure.

[0024] On the other hand, when a refrigerant is flowed through the cooling die, due to its function as a heat exchanger, the refrigerant temperature at the position (hereinafter also referred to as "position E1") closest to the outlet (hereinafter also referred to as "exit Ex") of the heat-treated material in the extruder extrusion direction among the refrigerant flow sections of the cooling die is preferably 50°C or less, from the viewpoint of excellent effect of improving texture and resistance to texture deterioration over time by using the cooling die described above, more preferably 40°C or less, and particularly preferably 35°C or less. Furthermore, it is preferable that the refrigerant at position E1 among the refrigerant flow sections of the cooling die is 5°C or more, from the viewpoint of preventing clogging at the extruder outlet and ensuring stable discharge of the contents. Note that when a cooling die has multiple separate refrigerant flow sections, position E1 refers to the position closest to the outlet Ex in the extruder extrusion direction among all the refrigerant flow sections. When the outlet Ex has a certain length in the extrusion direction of the extruder, the position E1 refers to the position closest to the end of the outlet Ex on the opposite side from the extruder. Hereinafter, in this specification, the refrigerant temperature at the position E1 will be referred to as the "cooling temperature on the outlet side of the cooling die."

[0025] Furthermore, due to the function of the heat exchanger, the cooling die has a refrigerant temperature of 40°C or less at the position (hereinafter also referred to as "position E2") closest to the inlet (hereinafter also referred to as "inlet In") of the heat-treated material in the extruder extrusion direction. This is preferable in terms of the excellent effect of improving the texture and resistance to texture deterioration over time by using the cooling die, and is more preferably 35°C or less, and particularly preferably 30°C or less. Furthermore, it is preferable that the refrigerant temperature at position E2 of the cooling die has a refrigerant temperature of 10°C or more in terms of preventing clogging at the extruder outlet and ensuring stable production stability by allowing the contents to be discharged stably. Note that, when a cooling die has multiple separate refrigerant flow sections, position E2 refers to the position closest to the inlet In in the extruder extrusion direction among all of the refrigerant flow sections. Note that, when the inlet In has a constant length in the extruder extrusion direction, position E2 refers to the position closest to the extruder-side end of the inlet In. In this specification, the refrigerant temperature at the position E2 will be referred to as the "cooling temperature on the inlet side of the cooling die."

[0026] In the extrusion direction of the extruder of the cooling die, the ratio (Lx / L) of the length Lx of the refrigerant flow portion in the same direction of the cooling die to the total length L of the cooling die in the same direction is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more. When the refrigerant flow portion is separated from the other portions in the same direction, the length Lx is the total length of the separated portions.

[0027] Among these, the cooling die preferably has a double-pipe structure as a heat exchanger, in which a refrigerant is disposed between the outer pipe and the inner pipe, and the contents are cooled by heat exchange with the refrigerant, in terms of excellent cooling function. The refrigerant preferably flows through at least the inlet side of the cooling die in the extrusion direction, and may flow through substantially the entire cooling die in the extrusion direction. In terms of heat exchange efficiency, it is preferable that the refrigerant flows in the cooling die in the direction opposite to the extrusion direction of the extruder.

[0028] The material of the inner tube of the cooling die having a double-tube structure is preferably, for example, metal, and more preferably stainless steel. Stainless steel SUS304 was used as the material of the inner tube of the cooling die in each example described below. The flow rate of the refrigerant is preferably 0.01 to 1 m / s, and more preferably 0.01 to 0.1 m / s. In each example described below in which a refrigerant was flowed through the cooling die, the refrigerant flow rate was within the range of 0.01 to 0.1 m / s.

[0029] From the viewpoint of ensuring that the desired effects of the present invention are achieved, the pressurizing pressure applied by the extruder is preferably 0.2 MPa or more, more preferably 0.2 to 10 MPa, even more preferably 0.2 to 9 MPa, and particularly preferably 0.3 to 9 MPa. Setting the pressurizing pressure at a certain level or less is preferable because it makes it possible to more stabilize the extrusion from the extruder and easily prevent a decrease in productivity. The "pressurizing pressure" refers to the pressure at the outlet of the extruder barrel.

[0030] From the same viewpoint, the heating temperature of the extruder is preferably 80°C or higher, more preferably 80 to 200°C, even more preferably 80 to 180°C, and particularly preferably 80 to 165°C. Setting the heating temperature at a certain level or lower is preferable because it makes extrusion from the extruder more stable and makes it easier to prevent a decrease in productivity. The "heating temperature" refers to the heating temperature of the barrel of the extruder.

[0031] In order to ensure that the desired effects of the present invention are achieved, the time (treatment time) for maintaining the pressure or higher and the heating temperature in the pressurized and heated treatment of the flour mixture using an extruder is preferably 5 seconds or more. From the same viewpoint, the upper limit of the time (treatment time) for maintaining the pressure or higher and the heating temperature is preferably 90 seconds or less, and more preferably 60 seconds or less.

[0032] From the viewpoint of ensuring production stability and texture improvement effects, the temperature of the heat-treated material at the cooling die outlet is preferably 180° C. or lower, and more preferably 160° C. or lower. There is no lower limit to the temperature of the heat-treated material at the cooling die outlet, but it may be, for example, 80° C. or higher, 100° C. or higher, 115° C. or higher, or 120° C. or higher.

[0033] By adding water to cereal flour and heating and pressurizing it using an extruder, the side chains of the starch are opened, thereby improving the texture of the food and its resistance to deterioration over time. To enhance this effect, the amount of water added per 100 parts by mass of cereal flour is preferably 40 parts by mass or more, more preferably 42 parts by mass or more, and particularly preferably 46 parts by mass or more.

[0034] From the viewpoint of production stability, the amount of water added to the flour during pressurized heating using an extruder is more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less, per 100 parts by mass of the flour. The amount of water added here refers to the total amount of water used from the raw flour to the production of the heat-treated flour, and may be saturated steam or water. Water may also be added to the flour in advance in a preconditioner process prior to the extruder process.

[0035] The raw material composition containing cereal flour and water is pressurized and heated using an extruder, and then extruded through a cooling die to obtain the desired heat-treated cereal flour.

[0036] In the manufacturing method of the present invention, it is preferable to subject the heat-treated flour obtained by the pressurized heat treatment using an extruder to a pulverization treatment. The pulverization treatment can be carried out according to conventional methods using a household pulverizer such as a coffee mill or juicer, or an industrial pulverizer such as a hammer mill, pin mill, or jet mill, by pulverizing the solid material to the desired particle size. The heat-treated flour extruded by the pressurized heat treatment can be dried before pulverization. The drying treatment reduces the moisture content of the heat-treated flour and can be carried out using known drying methods such as air drying and hot air drying. For example, the average particle size of the heat-treated flour is preferably 0.4 to 700.0 μm. The average particle size of the heat-treated flour in each example described below was within the above-mentioned range. In this specification, the term "average particle size" refers to the volume-cumulative particle size D50 at 50% cumulative volume when measured dry using a laser diffraction / scattering particle size distribution analyzer (e.g., Microtrac S3500, manufactured by Microtrac Bell Co., Ltd.).

[0037] (Raw Flours) In this specification, "flours" is a concept that includes starch and cereal flours whose main component is starch, and is a powdery substance that is in a powdery or granular form at room temperature and normal pressure. "Starch" as used herein refers to "pure starch" isolated from plants such as wheat, and is distinguished from starch that is inherently contained in cereal flour or whole grain flour. In this specification, whether "starch" refers to pure starch or includes starch that is inherently contained in cereal flour or whole grain flour is determined depending on the context.

[0038] The grains from which "flours" are derived include cereals (seeds of grass plants), pseudocereals (seeds of dicotyledonous plants), pulses (seeds of legumes), and potatoes (edible tuberous roots or stems), which contain starch as an ingredient.

[0039] Specific examples of flour include flours primarily composed of endosperm, such as wheat flour (specifically, for example, strong flour, medium flour, soft flour, durum wheat flour, and durum semolina), rice flour, buckwheat flour, rye flour, soy flour, barley flour, and corn flour, as well as flours containing at least the outer layer and the germ, such as "whole wheat flour" containing the three main components of the outer layer and the germ. Specific examples of whole wheat flour include whole wheat flour. Specific examples of starch include potato starch, wheat starch, corn starch, waxy corn starch, rice starch, and tapioca starch. The starch may be chemically modified. Chemical modification is a process in which a chemical agent is applied to starch to introduce a modifying group. Examples of chemically modified starch include acetylated adipic acid cross-linked starch, acetylated phosphate cross-linked starch, acetylated oxidized starch, sodium octenylsuccinate starch, starch acetate, oxidized starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, phosphorylated monoesterified phosphate cross-linked starch, phosphorylated starch, phosphate cross-linked starch, etc. The flour used in the present invention is preferably wheat flour, since the resulting heat-treated flour will have excellent texture and resistance to deterioration over time when used in foods, and low-amylose wheat flour is particularly preferred. Here, low-amylose wheat flour refers to wheat flour derived from wheat in which one or more genes selected from the Wx-A1 gene, the Wx-B1 gene, and the Wx-D1 gene have been deleted, and includes wheat flour derived from wheat in which the Wx-A1 gene, the Wx-B1 gene, or the Wx-D1 gene has been deleted (Haruyokoi, Sachikaori, Seto Kirara, Kitahonami, etc.); wheat flour derived from wheat in which two genes selected from the Wx-A1 gene, the Wx-B1 gene, and the Wx-D1 gene have been deleted (Ayahikari, Chikugoizumi, Tsurupikari, etc.); and wheat flour derived from wheat in which all of the Wx-A1 gene, the Wx-B1 gene, and the Wx-D1 gene have been deleted (Mochihime, Uraramochi, etc.).

[0040] (Heat-Treated Grain Flours) Heat-treated grain flours (hereinafter also referred to as "specific heat-treated grain flours") produced by the production method of the present invention can be used in place of known pregelatinized grain flours and pregelatinized starches, and can typically be used in the food industry to produce processed foods. The processed foods referred to here are those produced using grain flours as raw materials, and examples include noodles such as udon, somen, hiyamugi, Chinese noodles, pasta, and instant noodles (including non-fried noodles); bakery foods; fried foods such as tempura, fried chicken, tatsuta-age, and fritters; and powdered foods such as instant soups. Processed foods may also be frozen foods. The heat-treated grain flours obtained by the production method of the present invention are particularly suitable for bakery foods, and can produce bakery foods with a good texture and be conferred with anti-aging properties. Processed foods can be produced according to conventional methods depending on the type of processed food.

[0041] Next, a food composition containing the heat-treated flour of the present invention will be described. Food compositions of the present invention include those containing flours including the heat-treated flour of the present invention, preferably those containing the heat-treated flour of the present invention and unheat-treated flour, and particularly preferably those containing the heat-treated flour of the present invention and unheat-treated flour. Unheat-treated flours that can be used in combination with the heat-treated flour of the present invention may be raw flours (unprocessed flour, unprocessed starch) that have not been subjected to any processing such as heat treatment, or processed flours in which raw flours have been subjected to one or more processing treatments other than heat treatment (e.g., etherification, esterification, acetylation, cross-linking, oxidation, oil processing, etc.). Specific examples of raw flours are as described above. In the food composition, one type of grain flour other than the heat-treated flour of the present invention can be used alone, or two or more types can be used in combination.

[0042] The proportion of the heat-treated cereal flour of the present invention relative to the total cereal flour in the food composition is preferably 0.1 to 20% by mass, more preferably 5 to 10% by mass. Examples of such compositions include dough mixes. Examples of components used in the dough mix composition of the present invention include leavening agents such as sodium bicarbonate (baking soda), baking powder, ammonium carbonate, ammonium bicarbonate, and ammonium chloride, or yeast; oils and fats such as salad oil; sugars such as sugar; eggs such as whole eggs, egg whites, and egg yolks; dairy products such as milk, skim milk powder, and butter; salts such as salt; and additives such as emulsifiers, thickeners, acidulants, flavorings, spices, colorings, fruit juices, and vitamins. These may be used alone or in combination of two or more.

[0043] The heat-treated flours and food compositions of the present invention can be used to produce heated-dough foods. In the present invention, "heated-dough foods" refers to foods produced by mixing flour and / or starch with other ingredients to prepare uncooked dough, and then heating the dough, regardless of the method, such as baking, boiling, frying, or steaming. Examples of heated-dough foods to which the present invention is suitably applied include bakery foods, takoyaki, and okonomiyaki. In the present invention, "bakery foods" refers to foods obtained by subjecting batter dough, which is made primarily from flour and, if necessary, to additional ingredients such as yeast or a leavening agent (e.g., baking powder), water, salt, and sugar, to a heat treatment such as baking, steaming, or frying.

[0044] Bakery foods to which the present invention can be applied include breads; pizzas; cakes; Western-style baked goods such as waffles, choux pastries, biscuits, cookies, and crepes; Japanese sweets including taiyaki, imagawayaki, dorayaki, and ningyoyaki; oily sweets including cake donuts and ponde rings; and flour-based products including okonomiyaki and takoyaki. Examples of breads include white bread, rolls, white bread, brown bread, French bread, hardtack, buns, croissants, tortillas, cooked bread, sweet buns, and steamed bread. Examples of cakes include sponge cakes, butter cakes, rolls, hotcakes, bouche, baumkuchen, pound cakes, cheesecakes, snack cakes, muffins, bars, and pancakes. The bakery food of the present invention may be a bakery food obtained without fermentation with yeast, i.e., a bakery food obtained by heat-treating a non-yeast-fermented dough, or a bakery food obtained by fermentation with yeast, i.e., a bakery food obtained by heat-treating a yeast-fermented dough. Specific examples of bakery foods suitable for the present invention, particularly in terms of the effect of improving texture and resistance to deterioration of texture over time, include cakes (especially muffins, hotcakes, steamed cakes, pancakes, roll cakes, etc.); Japanese confectioneries; oil-based confectioneries; and flour-based products.

[0045] The heat-treated flour of the present invention can also be used in fields other than the food industry. Examples of uses of heat-treated flour in fields other than the food industry include, in the case of heat-treated flour produced using potato starch as the flour, caking of feed, caking of foundry sand molds, incense sticks, grinding stones, etc., household laundry glue, paper strength agent, etc.

[0046] Next, a method for improving the aging resistance of foods using heat-treated flour of the present invention will be described. This method uses the heat-treated flour obtained by the manufacturing method of the present invention described above. The explanations for the foods and food compositions using the heat-treated flour described above can be applied as appropriate to the method of use.

[0047] The present invention includes heat-treated flours produced by the manufacturing method of the present invention. As shown in the examples below, foods produced using the heat-treated flours of the present invention have excellent aging resistance. However, identifying the composition of the heat-treated wheat flour as a product that can be distinguished from heat-treated flours produced by conventional manufacturing methods requires the development of a new method for evaluating the characteristics of flours, which takes an extremely long time and is virtually impossible or impractical under the first-to-file system. For this reason, the present invention defines heat-treated flours as a product based on the manufacturing method.

[0048] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0049] Examples 1 to 12: Wheat flour was used as the cereal flour raw material, and water was added in the amount shown in Table 1. The mixture was heated and pressurized under the heat treatment conditions shown in Table 1, kneaded, and then discharged through an extruder process. A cooling die was attached to the extruder outlet. The cereal flour discharged from the cooling die outlet was cut to an appropriate length using a cutting device. The cut cereal flour was dried by leaving it in an ambient temperature of 90°C for 8 hours using a tray dryer, or by retaining it at 135°C for 8 minutes using a fluidized bed dryer. It was then coarsely pulverized using a roll mill and further pulverized using a pin mill so that the fraction remaining on a 100 μm mesh sieve was approximately 20% by mass. Heat-treated cereal flours were obtained through the above process. The applicant has confirmed that the differences in the drying methods described above do not affect the manufacturing stability described below or the texture of the resulting heat-treated cereal flours.

[0050] In the extruder, the time (treatment time) for maintaining the applied pressure and heating temperature in Table 1 was within the range of 15 to 60 seconds.

[0051] The cooling die had a cylindrical shape and was attached at the outlet of the extruder so that its cylindrical axis faced the same direction as the extruder extrusion direction. The cooling die had a double-pipe structure with an outer pipe and an inner pipe located inside it, and had the function of flowing a refrigerant (fluid) between the double pipes, cooling the contents by this function. The cooling temperature on the outlet side of the cooling die was 27°C. The cooling temperature on the inlet side of the cooling die was 30°C. The total length of the cooling die in the extruder extrusion direction was 257 mm. Furthermore, in the flow path of the heat-treated material consisting of the inside of the extruder barrel and the cooling die, the ratio (S1:S2) of the maximum area (maximum cross-sectional area of ​​the flow path, in this example, the cross-sectional area of ​​the barrel) S1 in a cross section perpendicular to the extruder extrusion direction to the area S2 of the outlet opening was within the range of 1:0.01 to 1.80. The ratio (Lx / L) of the length Lx of the refrigerant flow portion of the cooling die in the same direction to the total length L in the extruder extrusion direction was 30% or more. The temperature of the heat-treated material discharged from the cooling die was the temperature shown in Table 1.

[0052] Wheat flour: Chikugo Mugihata (wheat flour from Chikugo Izumi, manufactured by Nisshin Flour Milling Co., Ltd.) was used.

[0053] The twin-screw extruder used was a twin-screw extruder (manufactured by Nippon Tekkosho Co., Ltd., model TEX-47FSS-25BW-V). The screw diameter of this twin-screw extruder was 47 mm, and the opening area (mm ２ The ratio of the screw diameter (mm) of the extruder to the screw diameter (mm) of the extruder was 1.67. The screw diameters of the two screws of the twin-screw extruder were the same.

[0054] [Comparative Examples 2 to 8] A cooling die was not attached to the extruder outlet, and the kneaded material was discharged directly from the extruder outlet and cut. Except for these points, heat-treated flours were obtained in the same manner as in Examples 1 to 12.

[0055] (Evaluation of manufacturing stability) The manufacturing stability of heat-treated flours was evaluated according to the following criteria. A: Very good with no problems in the outlet clogging, blowing, cutting, or drying processes. B: Good, although clogging or blowing was observed at the outlet, or some lumps were observed after cutting. C: Clogging or blowing was observed at the outlet, and lumps were observed after cutting, making manufacturing difficult.

[0056] As described above, "blowing out at the outlet" refers to the blowing out of a liquid with a relatively low viscosity at the outlet. It is desirable for production stability that no or little such blowing out occurs. Furthermore, "lumps observed after cutting at the outlet" refers to the formation of lumps of heat-treated flour near the outlet due to the cross-sections created by cutting bonding together after cutting. Having few or no such lumps is desirable from the standpoint of continuous production, as it can prevent poor drying due to lumps and clogging due to lumps remaining near the cutting outlet.

[0057] (Production of Pancake Mix) A pancake mix, which is a type of processed food mix, was produced using any one of the heat-treated flours from the Examples and Comparative Examples. The composition of the produced pancake mix was 77.0% by mass of wheat flour, 19.2% by mass of sugar, and 3.8% by mass of baking powder (total 100% by mass). Of the wheat flour used in the pancake mix, 90% by mass was unprocessed wheat flour (soft flour, "Flour" manufactured by Nisshin Flour Milling Co., Ltd.), and the remaining 10% by mass was heat-treated wheat flour. A control pancake mix was produced in the same manner as above, except that only the unprocessed wheat flour was used as the wheat flour.

[0058] [Evaluation Test] Pancakes were made using the pancake mix according to the following method. The made pancakes were allowed to cool in an environment with an ambient temperature of 27°C for 30 minutes, and then the pancakes were wrapped in a wrapping film and stored in a refrigerator with an internal temperature of 4°C for 1 day and 3 days, respectively. The pancakes stored in the refrigerator for 1 day and 3 days were eaten by 10 expert panelists immediately after being taken out of the refrigerator, and the texture (moistness) was rated according to the following evaluation criteria. The average evaluation scores are shown in Table 1.

[0059] (Pancake Production) 65 g of pancake mix, 5 g of salad oil, 15 g of whole egg liquid, 25 g of milk, and an appropriate amount of water were added to a bowl and mixed by hand using a whisk at 120 revolutions per minute to prepare pancake batter having a viscosity of 5 to 10 Pa s as measured by a Brookfield viscometer at a product temperature of 25°C. The amount of water added was adjusted so that the viscosity of the pancake batter would fall within the above range. After allowing the pancake batter to rest for 10 minutes after preparation, 55 g of the batter was poured onto a griddle and baked on one side for 3 minutes at a griddle temperature of 180°C. The batter was then turned upside down and baked on the other side for 2 minutes to produce pancakes.

[0060] <Evaluation criteria for moist feeling> 5 points: Quite moist, very good. 4 points: Moist, good. 3 points: Slightly moist, good. 2 points: Not moist, slightly poor. 1 point: Not moist at all, poor.

[0061]

[0062] As shown in Table 1, in each Example in which a cooling die was attached to the extruder outlet during the extrusion process, the pressurization pressure inside the extruder was higher than in each Comparative Example in which a cooling die was not attached, and the moist feeling persisted even after 3 days of refrigerated storage. In contrast, in Comparative Examples 1 to 8 in which a cooling die was not used, the moist feeling after refrigerated storage was inferior. Furthermore, in Comparative Examples 7 and 8, blowing out of the heat-treated material at the extruder outlet was observed.

[0063] [Examples 13 to 27] In Example 10, the total length (mm) of the cooling die in the extruder extrusion direction, the extruder screw diameter (mm), and the pressurizing pressure (barrel tip pressure, MPa) were changed as shown in Table 2, and heat-treated flours were produced. The amount of water (parts by mass) added in the extruder process was changed. Other than this, evaluation was performed in the same manner as in Example 10. In Examples 13 and 14, where the extruder screw diameter (mm) was 65 mm, different from that in Example 10, a twin-screw extruder (Buhler Co., Ltd., model BCTG-62 / 20D) was used as the twin-screw extruder. In the table below, "none" for the die outlet side cooling temperature and inlet side cooling temperature indicates that no refrigerant was flowed through the cooling die. The evaluation results are shown in Table 2. Table 2 also shows the results of Example 10.

[0064]

[0065] Table 2 shows that, by comparing Example 15 with Example 10, flowing a refrigerant through the cooling die increases the pressure inside the extruder, and tends to result in greater effects such as improved texture. On the other hand, by comparing Examples 13 and 14 with Example 15, it is clear that in a cooling die having a double-pipe structure, adjusting the length and opening area can increase the internal pressure, and can enhance the effects such as improved texture that can be obtained even without flowing a refrigerant. Also, Table 2 shows that the cooling die (opening area of ​​the outlet opening mm ２ It can be seen that within the specified range expressed as (mm) / (screw diameter of extruder), the moist feeling persisted even after 3 days of refrigerated storage, and production stability was also good.

[0066] [Examples 28 and 29] In Example 10, the cooling temperature in the cooling die and whether or not cooling by flowing a refrigerant were performed were changed as shown in Table 3. Other than that, the same procedures as in Example 10 were carried out. The results are shown in Table 3. Table 3 also shows the results of Example 10.

[0067]

[0068] Table 3 also shows that by passing a refrigerant through a cooling die having a double pipe structure to enhance the cooling effect, the pressure inside the extruder can be increased, resulting in improved texture and other properties.

[0069] According to the present invention, it is possible to produce heat-treated cereal flours that can impart a good texture and resistance to deterioration of the texture over time to foods.

Claims

1. A method for producing heat-treated grain flour, comprising the steps of mixing grain flour with water using an extruder and heating and pressurizing the mixture to produce heat-treated grain flour, and attaching a cooling die to the outlet of the extruder for the material to be heat-treated.

2. In the cooling die, the opening area of ​​the outlet opening opening facing the extrusion direction of the extruder is 20 mm ２ 2. The method for producing heat-treated flours according to claim 1, wherein the total length of the cooling die in the extrusion direction of the extruder is 60 mm or more.

3. The opening area of ​​the outlet opening of the cooling die (mm ２ 2. The method for producing heat-treated grain flour according to claim 1, wherein the ratio of the mass of the grains per unit mass of the grains per unit mass of the extruder to the screw diameter of the extruder in mm is 0.11 or more and 11.8 or less.

4. The method for producing heat-treated cereal flour according to claim 1, wherein the extruder is a twin-screw extruder.

5. A method for producing heat-treated grain flour as described in claim 1, wherein the cooling die has a double-tube structure having an outer tube and an inner tube located inside the outer tube, and a refrigerant is circulated between the outer tube and the inner tube, cooling the contents by heat exchange with the refrigerant.

6. A method for producing heat-treated cereal flour as described in claim 1, wherein the amount of water mixed with the cereal flour in the extruder is 40 parts by mass or more per 100 parts by mass of cereal flour.

7. Heat-treated cereal flour produced by the method according to any one of claims 1 to 6.

8. A food product using the heat-treated grain flour according to claim 7.

9. A food composition using the heat-treated grain flour according to claim 7.

10. A method for improving the aging resistance of food using the heat-treated grain flour according to claim 7.

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