Method for producing starch composition

Abstract

The present invention relates to a method for producing a starch composition. The method for producing a starch composition according to the present invention comprises the steps of: (a) preparing a raw material mixture which contains a raw starch material, one or more selected from the group consisting of an acid-treated starch and a dextrin, and an aqueous alkaline solution, the raw material mixture having a moisture content of 20 parts by mass or more and 35 parts by mass or less per 100 parts by mass of the raw material mixture; and (b) heat-treating the raw material mixture having a moisture content of 20 parts by mass or more and 35 parts by mass or less obtained in step (a) to a temperature at which the raw material mixture becomes 120°C or higher and 150°C or lower. The present invention can provide a starch composition that does not swell or swell less upon heating and that is heat resistant, using a simple method.

Description

Method for producing starch composition

[0001] The present invention relates to a method for producing a starch composition.

[0002] In recent years, consumers have become increasingly concerned about food safety and security, and the demand for clean-labeled products with a natural feel has been rapidly expanding. However, the requirements for processed foods, such as texture and ease of use, are only increasing. Therefore, there is a need for food labels to provide foods that have a natural feel and are functional. Regarding starches, there is also a need for new materials that impart similar functions to conventional processed starches without the need for substances or chemical treatments that must be listed on food labels. Among processed starches, cross-linked starches are used in various processed foods because they are highly soluble in water and exhibit minimal swelling upon heating. For example, Patent Document 1 describes that thermally inhibited starches with similar functions to cross-linked starches can be obtained by dehydrating starch to a substantially anhydrous state and then heat-treating it at a temperature of 100°C or higher. Patent Document 2 also describes that thermally inhibited starches can be obtained by blending starch and oligosaccharides in an aqueous solution to form a slurry, dehydrating the mixture to an anhydrous or substantially anhydrous state, and then heat-treating the mixture.

[0003] JP-T-9-503549A JP-A-2003-501494A

[0004] However, conventional methods have had problems such as the elution of starch raw material and auxiliary raw material components into the dehydration solution during the dehydration step, the susceptibility of starch raw materials to heat damage during the dehydration and heating steps, and the need for a large number of steps and equipment, resulting in reduced productivity. Furthermore, attempts have been made to highly crosslink crosslink crosslinked starches in order to suppress swelling during heating, but a high degree of crosslinking reduces the maximum viscosity during heating, making it difficult to impart a desired texture to foods. Under these circumstances, it is desirable to provide a starch composition that has the same functions as crosslinked starch, which does not swell or swells less when heated and is heat-resistant, using a simpler method. It is even more desirable to provide a starch composition that has a maximum viscosity similar to that of the starch raw material, but which swells less when heated or is heat-resistant.

[0005] The present invention provides the following methods for producing starch compositions. [1] A method for producing a starch composition, comprising: (a) preparing a raw material mixture containing a starch raw material, one or more selected from the group consisting of acid-treated starch and dextrin, and an alkaline aqueous solution, the raw material mixture having a water content of 20 to 35 parts by mass relative to 100 parts by mass of the raw material mixture; and (b) heat-treating the raw material mixture having a water content of 20 to 35 parts by mass obtained in step (a) to a temperature at which the raw material mixture is heated to 120°C to 150°C. [2] A method for producing a starch composition according to [1] above, wherein the mass ratio of the starch raw material to 100 parts by mass of the raw material mixture is 56 to 79 parts by mass. [3] A method for producing a starch composition according to [1] or [2] above, wherein the mass ratio of the acid-treated starch to 100 parts by mass of the raw material mixture is 0.5 to 20 parts by mass. [4] A method for producing the starch composition according to any one of [1] to [3], wherein the mass ratio of the dextrin to 100 parts by mass of the raw material mixture is 0.1 parts by mass or more and 20 parts by mass or less. [5] A method for producing the starch composition according to any one of [1] to [4], wherein the number average molecular weight of the acid-treated starch is 250,000 or more and 500,000 or less. [6] A method for producing the starch composition according to any one of [1] to [5], wherein the DE (degree of hydrolysis) of the dextrin is 5 or more and less than 50. [7] A method for producing the starch composition according to any one of [1] to [6], wherein the dextrin is in the form of an aqueous dextrin solution. [8] A method for producing the starch composition according to any one of [1] to [7], wherein the alkali used in the aqueous alkaline solution is one or more selected from the group consisting of calcium hydroxide, sodium carbonate, calcium carbonate, potassium carbonate, sodium hydrogencarbonate, and dipotassium hydrogenphosphate. [9] The method for producing a starch composition according to any one of [1] to [8], wherein a step of dehydrating the raw material mixture until the water content of the raw material mixture is less than 1 part by mass per 100 parts by mass of the raw material mixture is not required between steps (a) and (b).

[10] The method for producing a starch composition according to any one of [1] to [9], wherein the raw material mixture further contains an edible oil or fat.

[11] The method for producing a starch composition according to

[10] above, wherein the mass ratio of the edible oil or fat to 100 parts by mass of the raw material mixture is 0.05 parts by mass or more and 1.5 parts by mass or less.

[12] The method for producing a starch composition according to any one of [1] to [9] above, further comprising: (c) a step of adding water and a pH adjuster to the heat-treated product obtained in step (b) to perform a washing treatment; and (d) a step of dehydrating or drying the washed product obtained in step (c).

[0006] According to the present invention, it is possible to provide a starch composition having a swelling-inhibiting function similar to that of a chemically crosslinked starch by a simpler method. According to a preferred embodiment of the present invention, it is possible to provide a starch composition having a maximum viscosity close to that of the starch raw material, a high swelling-inhibiting effect when heated, and retort resistance.

[0007] The present invention will be described in more detail below. In the present invention, by blending an edible oil or fat into a raw material mixture in addition to a starch raw material, one or more members selected from the group consisting of acid-treated starch and dextrin, and an alkaline aqueous solution, not only can the starch raw material be endowed with a swelling-inhibiting function upon heating, but also oil or fat processing can be performed. Below, a first embodiment in which no edible oil or fat is blended into the raw material mixture and a second embodiment in which edible oil or fat is blended into the raw material mixture will be described.

[0008] 1. Method for Producing Starch Composition (First Aspect) A method for producing a starch composition according to a first aspect of the present invention includes the following steps: (a) preparing a raw material mixture containing a starch raw material, one or more selected from the group consisting of acid-treated starch and dextrin, and an alkaline aqueous solution, the raw material mixture having a water content of 20 to 35 parts by mass relative to 100 parts by mass of the raw material mixture (hereinafter also referred to as "step (a)"); and (b) heating the raw material mixture having a water content of 20 to 35 parts by mass obtained in step (a) to a temperature at which the raw material mixture is heated to 120°C to 150°C (hereinafter also referred to as "step (b)").

[0009] In the present invention, a raw material mixture having a predetermined water content is directly heat-treated without requiring a step of dehydrating the raw material mixture until the water content of the raw material mixture becomes less than 1 part by mass per 100 parts by mass of the raw material mixture (i.e., less than 1% by mass of the raw material mixture), thereby imparting a swelling-inhibiting function to the starch raw material while preventing loss and thermal damage of the starch raw material and auxiliary raw material components that are associated with the dehydration treatment.

[0010] Each step will be described in detail below.

[0011] <Step (a)> In step (a), a raw material mixture is prepared, which contains a starch raw material, one or more members selected from the group consisting of acid-treated starch and dextrin, and an alkaline aqueous solution, and has a water content of 20 parts by mass or more and 35 parts by mass or less per 100 parts by mass of the raw material mixture.

[0012] The starch raw material is not particularly limited as long as it is a starch raw material used in foods, but is preferably one that does not involve chemical treatment, and unmodified starch is more preferred. Preferred examples of unmodified starches include starches derived from plants. Specific examples of plants from which unmodified starch is derived include regular corn (regular corn or dent corn), waxy corn (waxy corn), high-amylose corn, non-glutinous rice, glutinous rice, wheat, sweet potato, potato, pea, mung bean, cassava, and sago palm, among others. Preferred examples include regular corn, waxy corn, high-amylose corn, non-glutinous rice, glutinous rice, wheat, potato, pea, mung bean, and cassava, more preferred examples include regular corn, waxy corn, high-amylose corn, glutinous rice, potato, pea, and cassava, and even more preferred examples include regular corn, waxy corn, potato, pea, and cassava. The starch raw material may be appropriately selected depending on the purpose and application.

[0013] The mass ratio of the starch raw material relative to 100 parts by mass of the raw material mixture is not particularly limited, but is preferably 56 parts by mass or more and 79 parts by mass or less, more preferably 56 parts by mass or more and 75 parts by mass or less, even more preferably 56 parts by mass or more and 70 parts by mass or less, and particularly preferably 58 parts by mass or more and 68 parts by mass or less.

[0014] In addition, when a numerical range is shown in this specification, the upper limit and lower limit of each numerical range can be combined as appropriate.

[0015] Either one of the acid-treated starch and the dextrin may be used alone, or both of the acid-treated starch and the dextrin may be used. In the present invention, by including one or more of the acid-treated starch and the dextrin in the raw material mixture, even if the raw material mixture contains a certain amount of water, acid hydrolysis of the starch raw material accompanying the heat treatment in step (b) can be suppressed, and a starch composition having the desired swelling-inhibiting function can be obtained.

[0016] The acid-treated starch is not particularly limited as long as it is a starch raw material that has been subjected to an acid treatment. Preferred starch raw materials for the acid-treated starch include unmodified starches, such as regular corn, waxy corn, high-amylose corn, non-glutinous rice, waxy rice, wheat, potato, pea, mung bean, cassava, and sago palm, more preferably regular corn, waxy corn, high-amylose corn, waxy rice, potato, pea, and cassava, and even more preferably regular corn, waxy corn, high-amylose corn, pea, cassava, and potato.

[0017] Acid-treated starch is obtained by treating a starch raw material in an acid solution. Specific examples of the acid used for the acid treatment include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid.

[0018] The number-average molecular weight of the acid-treated starch is preferably 250,000 or more and 500,000 or less, more preferably 250,000 or more and 450,000 or less, more preferably 270,000 or more and 400,000 or less, even more preferably 300,000 or more and 370,000 or less, and particularly preferably 300,000 or more and 350,000 or less. The number-average molecular weight of the acid-treated starch can be measured by gel permeation chromatography (GPC) using pullulan as the standard substance.

[0019] The mass ratio of the acid-treated starch to 100 parts by mass of the raw material mixture is not particularly limited, but is preferably from 0.5 to 20 parts by mass, more preferably from 0.5 to 18 parts by mass, even more preferably from 0.8 to 18 parts by mass, particularly preferably from 0.8 to 15 parts by mass, still more preferably from 0.8 to 13 parts by mass, and even more preferably from 0.8 to 10 parts by mass. However, when the raw material mixture does not contain dextrin, the mass ratio of the acid-treated starch to 100 parts by mass of the raw material mixture is preferably from 0.5 to 20 parts by mass, more preferably from 0.8 to 20 parts by mass, even more preferably from 0.8 to 18 parts by mass, and particularly preferably from 0.8 to 15 parts by mass.

[0020] By blending acid-treated starch into the raw material mixture, it is possible to obtain a starch composition having functions similar to those of crosslinked starch, such as low swelling upon heating or heat resistance. Furthermore, according to a preferred embodiment of the present invention, it is possible to obtain a starch composition having a maximum viscosity close to that of the starch raw material, low swelling upon heating or heat resistance. Furthermore, according to a preferred embodiment of the present invention, it is possible to obtain a starch composition that can be suppressed from discoloring and has unlimited uses.

[0021] The dextrin is not particularly limited, but the DE (degree of decomposition) of the dextrin is preferably 5 or more but less than 50, and more preferably 5 or more but 35 or less. The DE of the dextrin is a relative measure of reducing power, with the reducing power of glucose, a typical reducing sugar, being set at 100, and serves as an index of the degree of decomposition. The DE of the dextrin is more preferably 5 or more but 33 or less, even more preferably 10 or more but 30 or less, and particularly preferably 15 or more but 30 or less. From the viewpoint of suppressing discoloration of the starch composition, the DE of the dextrin is preferably within the above range. The DE of the dextrin can be measured by the method described in "Starch and Sugar Related Industrial Analysis Methods" published by Food Chemical Newspaper Co., Ltd., pp. 107-108, 1991.

[0022] The mass ratio of dextrin to 100 parts by mass of the raw material mixture is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 15 parts by mass, even more preferably 0.2 to 10 parts by mass, and particularly preferably 0.3 to 8 parts by mass. However, when the raw material mixture does not contain acid-treated starch, the mass ratio of dextrin to 100 parts by mass of the raw material mixture is preferably 0.5 to 20 parts by mass, more preferably 0.5 to 18 parts by mass, even more preferably 0.5 to 15 parts by mass, particularly preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass.

[0023] By blending dextrin into the raw material mixture, it is possible to obtain a starch composition having functions similar to crosslinked starch, such as low swelling upon heating or heat resistance. According to a preferred embodiment of the present invention, it is possible to obtain a starch composition having a maximum viscosity similar to that of the starch raw material, while low swelling upon heating or heat resistance. It is also possible to obtain a starch composition having a smooth viscosity upon addition of water. Furthermore, it is possible to obtain a starch composition having retort resistance, with little change in texture and feel before and after retort (pressure heating treatment).

[0024] Dextrin may be added to the raw material mixture in powder, granular, or liquid form, or may be dissolved in water in advance and added to the raw material mixture as a dextrin aqueous solution. Using a dextrin aqueous solution allows dextrin to act more uniformly on the starch raw material. In this case, the mass ratio of dextrin contained in the dextrin aqueous solution relative to 100 parts by mass of the raw material mixture may be within the above-mentioned range, as calculated by the mass of dextrin. The water content of the dextrin aqueous solution, including the water content of the alkaline aqueous solution described below, may be within the range of 20 to 35 parts by mass relative to 100 parts by mass of the raw material mixture. In the present invention, water is not particularly limited as long as it is suitable for use in foods, and examples thereof include natural water and tap water.

[0025] In the present invention, acid-treated starch and dextrin can also be used in combination. According to a preferred embodiment of the present invention, the combined use of acid-treated starch and dextrin not only imparts swelling-inhibiting properties to the starch raw material but also imparts retort resistance, thereby providing a starch composition that has smooth viscosity and little coloration when water is added.

[0026] When acid-treated starch and dextrin are used in combination, the mass ratio of the acid-treated starch to 100 parts by mass of the raw material mixture is not particularly limited, but is preferably from 0.5 to 20 parts by mass, more preferably from 0.5 to 15 parts by mass, even more preferably from 0.8 to 13 parts by mass, particularly preferably from 0.8 to 10 parts by mass, still more preferably from 0.8 to 8 parts by mass, and even more preferably from 0.8 to 5 parts by mass. The mass ratio of dextrin to 100 parts by mass of the raw material mixture is preferably from 0.1 to 20 parts by mass, more preferably from 0.2 to 15 parts by mass, even more preferably from 0.2 to 10 parts by mass, particularly preferably from 0.3 to 8 parts by mass, and even more preferably from 0.3 to 5 parts by mass. Furthermore, the total mass ratio of the acid-treated starch and dextrin relative to 100 parts by mass of the raw material mixture is usually from 0.6 to 24 parts by mass, preferably from 0.6 to 15 parts by mass, more preferably from 0.6 to 10 parts by mass, even more preferably from 1 to 10 parts by mass, and particularly preferably from 2.5 to 7.5 parts by mass.

[0027] In the present invention, the pH of the alkaline aqueous solution is preferably 9.0 to 10.5, more preferably 9.0 to 10.0, even more preferably 9.0 to 9.8, and particularly preferably 9.2 to 9.7.

[0028] The alkali used in the alkaline aqueous solution is not particularly limited as long as it is one that is used in foods, and is preferably at least one selected from the group consisting of calcium hydroxide, sodium carbonate, calcium carbonate, potassium carbonate, sodium bicarbonate, and dipotassium hydrogen phosphate, more preferably sodium carbonate, potassium carbonate, sodium bicarbonate, and dipotassium hydrogen phosphate, and even more preferably sodium carbonate and sodium bicarbonate.

[0029] The mass ratio of the alkali relative to 100 parts by mass of the raw material mixture is preferably 0.05 parts by mass or more and 0.5 parts by mass or less, more preferably 0.05 parts by mass or more and 0.4 parts by mass or less, even more preferably 0.1 parts by mass or more and 0.3 parts by mass or less, and particularly preferably 0.15 parts by mass or more and 0.3 parts by mass or less.

[0030] In step (a), the raw material mixture is adjusted to have a water content of 20 to 35 parts by mass relative to 100 parts by mass of the raw material mixture. The water content of the raw material mixture is preferably 22 to 35 parts by mass, more preferably 25 to 35 parts by mass, even more preferably 25 to 33 parts by mass, and particularly preferably 27 to 33 parts by mass, relative to 100 parts by mass of the raw material mixture.

[0031] The amount of water contained in the alkaline aqueous solution may be in any range as long as the water content of the raw material mixture satisfies the above-mentioned range. When a dextrin aqueous solution is used as the dextrin, as described above, the total amount of water contained in the alkaline aqueous solution and the dextrin aqueous solution may be in any range as long as the total amount of water contained in the dextrin aqueous solution satisfies the above-mentioned range.

[0032] In step (a), a raw material mixture is prepared by mixing a starch raw material, one or more members selected from the group consisting of acid-treated starch and dextrin, and an alkaline aqueous solution. Specifically, the raw material mixture can be prepared, for example, as follows.

[0033] First, an alkali is weighed and dissolved in water to prepare an alkaline aqueous solution. Next, a starch raw material and one or more selected from the group consisting of acid-treated starch and dextrin are weighed and charged into a mixer. While stirring, the alkaline aqueous solution is added and further stirring is performed. To ensure a more uniform mixture, it is preferable to stop stirring midway and remove any raw material mixture adhering to the inner wall of the container and the mixer, and then further stir.

[0034] When an aqueous dextrin solution is used, the aqueous dextrin solution may be prepared separately from the aqueous alkali solution and added to the mixer, or the alkali and dextrin may be dissolved together in water to prepare an aqueous solution containing the alkali and dextrin, which may then be added to the mixer.

[0035] Specifically, first, the alkali and dextrin are each weighed and dissolved in water to prepare an aqueous solution. Next, the starch raw material and optionally the acid-treated starch are each weighed and added to a mixer. Subsequently, while stirring the starch raw material and optionally the acid-treated starch in the mixer, the aqueous solution is added and further stirred. In this case, too, to ensure more uniform mixing, it is preferable to stop stirring midway and remove any raw material mixture adhering to the inner wall of the container and the mixer, and then further stir.

[0036] As described above, the components are mixed until they become uniform, to prepare a raw material mixture having a water content of 20 parts by mass or more and 35 parts by mass or less per 100 parts by mass of the raw material mixture.

[0037] <Step (b)> Next, in step (b), the raw material mixture having a water content of 20 parts by mass or more and 35 parts by mass or less obtained in step (a) is heat-treated to a temperature at which the raw material mixture is heated ...

[0038] The heat treatment temperature is up to a temperature at which the raw material mixture is heated to 120° C. or higher and 150° C. or lower, preferably up to a temperature at which the raw material mixture is heated to 120° C. or higher and 145° C. or lower, more preferably up to a temperature at which the raw material mixture is heated to 125° C. or higher and 145° C. or lower, and even more preferably up to a temperature at which the raw material mixture is heated to 125° C. or higher and 140° C. When heating is started, the temperature of the raw material mixture gradually increases, but the heat treatment temperature referred to here is the temperature of the raw material mixture (heat-treated product) at the end of the heat treatment, and is essentially the maximum temperature of the raw material mixture during the heat treatment.

[0039] The heat treatment method is not particularly limited as long as it can heat-treat a raw material mixture having a moisture content of 20 parts by mass or more and 35 parts by mass or less at the above-mentioned temperature, and various heating / drying devices can be used, such as a tray-type hot air circulation dryer (hereinafter also referred to as a "tray-type dryer"), a tabletop heating / stirring machine, an airflow dryer, a band ventilation dryer, a fluidized bed dryer, a rotary dryer, a disk dryer, a cylindrical dryer, and an inverted cone mixer dryer.

[0040] For example, when heat treatment is performed using a tray-type hot air circulation dryer, the raw material mixture is spread evenly on a tray, and the tray is placed in the temperature-controlled dryer and heat treatment is performed. It is preferable to stir the mixture over time and perform sampling to ensure uniform heat treatment. The heating time is preferably approximately 1 hour to 6 hours, more preferably 1 hour to 4 hours, and even more preferably 2 hours 30 minutes to 3 hours 30 minutes. After completion of the heat treatment, the mixture is cooled. If necessary, a holding time may be set at the heat treatment temperature. The holding time is preferably 0.5 hours to 5 hours, more preferably 0.5 hours to 3 hours, and even more preferably 0.5 hours to 1 hour. The completion of the heat treatment can be determined by the viscosity pattern (breakdown, etc.).

[0041] When heat treatment is performed using a tabletop heating and stirring machine, the temperature of the raw material mixture can be raised quickly by setting the pot to the set temperature, and uniform heating can be achieved by stirring the raw material mixture with a stirring blade. However, even in this case, it is preferable to stir and sample the mixture over time to ensure more uniform heat treatment. The heating time is preferably from 1 hour to 6 hours, more preferably from 1 hour to 4 hours, and even more preferably from 2 hours 30 minutes to 3 hours 30 minutes. After the heat treatment is completed, the mixture is cooled.

[0042] Steps (a) and (b) may be carried out continuously in the same apparatus. For example, steps (a) and (b) can be carried out continuously using a powder / granule mixer / dryer (e.g., "Ribocone" manufactured by Okawara Manufacturing Co., Ltd.) equipped with a vertical inverted conical container and a spiral ribbon rotor. Specifically, first, an alkali is weighed and dissolved in water to prepare an alkaline aqueous solution. Next, a starch raw material and one or more members selected from the group consisting of acid-treated starch and dextrin are weighed and added to a mixer. Then, stirring and heating of the mixer are initiated. Next, the alkaline aqueous solution is added to the mixer. To ensure a more uniform reaction, it is preferable to add the alkaline aqueous solution at a constant rate. Sampling is performed over time, and the mixture is cooled upon completion of the heat treatment.

[0043] When using an aqueous dextrin solution, the aqueous dextrin solution may be prepared separately from the aqueous alkali solution and added to the mixer, or the alkali and dextrin may be dissolved in water to prepare an aqueous solution containing the alkali and dextrin, which may then be added to the mixer.

[0044] Specifically, first, the alkali and dextrin are weighed and dissolved in water to prepare an aqueous solution. Next, the starch raw material and, optionally, the acid-treated starch are weighed and added to a mixer. Then, stirring and heating of the mixer are started. Next, the aqueous solution is added to the mixer. In this case, too, it is preferable to add the aqueous solution at a constant rate to ensure a more uniform reaction. Sampling is performed over time, and the mixture is cooled once the heat treatment is complete.

[0045] In the first aspect of the present invention, the target starch composition can be obtained by performing steps (a) and (b) as described above. In the present invention, the target starch composition can be obtained without the need for a dehydration step between steps (a) and (b) to reduce the water content of the raw material mixture to less than 1 part by mass per 100 parts by mass of the raw material mixture. Because the dehydration step between steps (a) and (b) is not required, the present invention can prevent the starch raw material, acid-treated starch, dextrin, alkali, and other auxiliary raw material components from leaching into the dehydration solution and reduce the wastewater load caused by the leached components. Furthermore, heat damage to the starch raw material can be minimized by eliminating the dehydration step that employs a drying step. Furthermore, the production process and equipment can be simplified, improving productivity.

[0046] The resulting starch composition is subjected to a step (step (c)) of washing with the addition of water and a pH adjuster, as needed, and then a step (step (d)) of dehydrating or drying the washed product. By performing steps (c) and (d), the retort resistance of the resulting starch composition can be improved.

[0047] Steps (c) and (d) will be described below.

[0048] <Step (c)> In step (c), water and a pH adjuster are added to the heat-treated product obtained in step (b) and a washing treatment is performed. In step (c), the heat-treated product obtained in step (b) is washed to remove the alkali, thereby decolorizing and neutralizing the heat-treated product. According to a preferred embodiment of the present invention, this improves the retort resistance, suppression of heat swelling, increase in final viscosity, and transparency when water is added to the resulting starch composition. The mass ratio of water to 100 parts by mass of the heat-treated product is preferably 300 parts by mass or more and 1,000 parts by mass or less, more preferably 300 parts by mass or more and 800 parts by mass or less, even more preferably 400 parts by mass or more and 800 parts by mass or less, and particularly preferably 400 parts by mass or more and 500 parts by mass or less. The pH adjuster is not particularly limited as long as it is one that is commonly used in food applications, and examples thereof include adipic acid, citric acid, trisodium citrate, gluconic acid, succinic acid, lactic acid, potassium carbonate, sodium hydrogen carbonate, sodium hydrogen phosphate, dipotassium hydrogen phosphate, sodium pyrophosphate, sodium metaphosphate, sodium polyphosphate, etc. The amount of pH adjuster used is appropriately determined so that the pH value when water and the pH adjuster are added to the heat-treated product is preferably in the range of 4 or more and 7 or less, more preferably 5 or more and 7 or less, and even more preferably 5 or more and 6 or less.

[0049] <Step (d)> In step (d), the washed product obtained in step (c) is dehydrated or dried. The dehydration or drying can be performed using a machine such as a centrifuge, filter press, drum dryer, spray dryer, air blower, flash dryer, fluidized bed dryer, fluidized bed dryer, or flash dryer. In the present invention, it is preferable to perform the dehydration or drying using a centrifuge or flash dryer that is used in existing equipment.

[0050] The dehydration or drying treatment is carried out until the water content of the final starch composition is preferably 15 parts by mass or less per 100 parts by mass of the raw material mixture.

[0051] In the first aspect of the present invention, by performing steps (a) and (b), and further, if necessary, steps (c) and (d), a starch composition similar in function to crosslinked starch, such as exhibiting low swelling upon heating or heat resistance, can be obtained, thereby obtaining a starch composition with swelling-inhibiting properties. Furthermore, according to a preferred embodiment, a starch composition can be obtained that exhibits a maximum viscosity similar to that of the starch raw material, while exhibiting low swelling upon heating or heat resistance. Furthermore, according to a preferred embodiment, the starch composition obtained by this production method exhibits smooth viscosity upon addition of water, and exhibits little change in texture before and after retort, making it retort-resistant. Furthermore, according to a preferred embodiment, the starch composition obtained by this production method exhibits little coloration and can be used in a wide range of applications. The starch composition obtained by this production method can be preferably used as a starch composition for various foods, such as curry, hash brown, stew, soup, sauce, dressing, processed meat and fish foods, and processed vegetable protein foods.

[0052] 2. Method for Producing a Starch Composition (Second Aspect) In the second aspect of the present invention, in step (a), a raw material mixture is prepared that further contains an edible oil or fat in addition to a starch raw material, one or more members selected from the group consisting of acid-treated starch and dextrin, and an alkaline aqueous solution. The inclusion of an edible oil or fat in the raw material mixture not only imparts swelling-inhibiting properties to the starch raw material, but also enables the starch raw material to be subjected to an oil or fat processing treatment.

[0053] That is, the method for producing a starch composition according to the second aspect of the present invention is characterized by comprising: (a) a step of preparing a raw material mixture containing a starch raw material, one or more selected from the group consisting of acid-treated starch and dextrin, an alkaline aqueous solution, and edible oils and fats, the raw material mixture having a water content of 20 to 35 parts by mass relative to 100 parts by mass of the raw material mixture; and (b) a step of heat-treating the raw material mixture having a water content of 20 to 35 parts by mass obtained in step (a) to a temperature at which the raw material mixture is heated to 120°C to 150°C.

[0054] <Step (a)> In the method for producing a starch composition according to the second aspect, step (a) is the same as step (a) in the method for producing a starch composition according to the first aspect, except that the raw material mixture further contains an edible oil or fat.

[0055] The starch raw material, the one or more members selected from the group consisting of acid-treated starch and dextrin, and the alkaline aqueous solution can be the same as those described in the first embodiment.

[0056] The mass ratios of the starch raw material, one or more selected from the group consisting of acid-treated starch and dextrin, and the alkaline aqueous solution per 100 parts by mass of the raw material mixture are the same as those described in the first embodiment, but may be adjusted appropriately depending on the amount of edible oil or fat added. For example, the mass ratio of the starch raw material per 100 parts by mass of the raw material mixture is preferably 56 to 79 parts by mass, more preferably 56 to 75 parts by mass, even more preferably 56 to 70 parts by mass, and particularly preferably 58 to 68 parts by mass. Furthermore, when acid-treated starch is used, the mass ratio of the acid-treated starch per 100 parts by mass of the raw material mixture is preferably 0.5 to 20 parts by mass, more preferably 0.5 to 18 parts by mass, even more preferably 0.8 to 18 parts by mass, particularly preferably 0.8 to 15 parts by mass, even more preferably 0.8 to 13 parts by mass, and even more preferably 0.8 to 10 parts by mass. However, when the raw material mixture does not contain dextrin, the mass ratio of the acid-treated starch to 100 parts by mass of the raw material mixture is preferably from 0.5 to 20 parts by mass, more preferably from 0.8 to 20 parts by mass, even more preferably from 0.8 to 18 parts by mass, and particularly preferably from 0.8 to 15 parts by mass. When dextrin is used, the mass ratio of the dextrin to 100 parts by mass of the raw material mixture is preferably from 0.1 to 20 parts by mass, more preferably from 0.2 to 18 parts by mass, even more preferably from 0.2 to 15 parts by mass, particularly preferably from 0.2 to 10 parts by mass, and even more preferably from 0.3 to 8 parts by mass. However, when the raw material mixture does not contain acid-treated starch, the mass ratio of dextrin relative to 100 parts by mass of the raw material mixture is preferably 0.5 parts by mass or more and 20 parts by mass or less, more preferably 0.5 parts by mass or more and 18 parts by mass or less, even more preferably 0.5 parts by mass or more and 15 parts by mass or less, particularly preferably 0.5 parts by mass or more and 10 parts by mass or less, and even more preferably 0.5 parts by mass or more and 8 parts by mass or less.When acid-treated starch and dextrin are used in combination, the mass ratio of the acid-treated starch to 100 parts by mass of the raw material mixture is not particularly limited, but is preferably from 0.5 to 20 parts by mass, more preferably from 0.5 to 15 parts by mass, even more preferably from 0.8 to 13 parts by mass, particularly preferably from 0.8 to 10 parts by mass, still more preferably from 0.8 to 8 parts by mass, and even more preferably from 0.8 to 5 parts by mass. The mass ratio of dextrin to 100 parts by mass of the raw material mixture is preferably from 0.1 to 20 parts by mass, more preferably from 0.2 to 15 parts by mass, even more preferably from 0.2 to 10 parts by mass, particularly preferably from 0.3 to 8 parts by mass, and even more preferably from 0.3 to 5 parts by mass. Furthermore, the total mass ratio of the acid-treated starch and dextrin relative to 100 parts by mass of the raw material mixture is usually from 0.6 parts by mass to less than 24 parts by mass, preferably from 0.6 parts by mass to 15 parts by mass, more preferably from 0.6 parts by mass to 10 parts by mass, even more preferably from 1 part by mass to 10 parts by mass, and particularly preferably from 2.5 parts by mass to 7.5 parts by mass.

[0057] The edible oils and fats are not particularly limited as long as they are used in foods. Examples include vegetable oils and fats such as soybean oil, rapeseed oil, corn oil, cottonseed oil, rice oil, sunflower oil, and high linoleic safflower oil, sesame oil, olive oil, peanut oil, kapok oil, evening primrose oil, linseed oil, perilla oil, palm oil, palm kernel oil, and coconut oil; animal oils and fats such as fish oil, lard, beef tallow, and milk fat; and medium-chain fatty acid triglycerides, and processed oils and fats obtained by subjecting these to one or more processes selected from the group consisting of interesterification, hydrogenation, and fractionation. Among these, the edible oils and fats to be used are preferably those with an iodine value of 100 or more, and more preferably those with an iodine value of 140 or more. Specifically, one or more selected from the group consisting of soybean oil, rapeseed oil, corn oil, cottonseed oil, rice bran oil, sunflower oil, high linoleic acid safflower oil, sesame oil, olive oil, linseed oil, perilla oil, and coconut oil are preferred, and one or more selected from the group consisting of soybean oil, rapeseed oil, corn oil, sunflower oil, high linoleic acid safflower oil, olive oil, linseed oil, and coconut oil are more preferred. Examples of oils and fats having an iodine value of 140 or higher include high linoleic acid safflower oil and linseed oil, with high linoleic acid safflower oil being preferred.

[0058] The mass ratio of edible oils and fats relative to 100 parts by mass of the raw material mixture is preferably 0.05 parts by mass or more and 1.5 parts by mass or less, more preferably 0.08 parts by mass or more and 1.5 parts by mass or less, even more preferably 0.1 parts by mass or more and 1 part by mass or less, and particularly preferably 0.1 parts by mass or more and 0.8 parts by mass or less.

[0059] In step (a) according to the second embodiment, a raw material mixture is prepared by mixing a starch raw material, one or more members selected from the group consisting of acid-treated starch and dextrin, an alkaline aqueous solution, and an edible oil or fat. Specifically, the raw material mixture can be prepared, for example, as follows.

[0060] First, an alkali is weighed and dissolved in water to prepare an alkaline aqueous solution. Next, a starch raw material and one or more selected from the group consisting of acid-treated starch and dextrin are weighed and added to a mixer. Next, while stirring the starch raw material and one or more selected from the group consisting of acid-treated starch and dextrin in the mixer, an alkaline aqueous solution is added and further stirred. Alternatively, the acid-treated starch and dextrin may be mixed with the alkaline aqueous solution and then mixed with the starch raw material. Next, an edible oil or fat is added and further stirred. Alternatively, the edible oil or fat may be added simultaneously with the alkaline aqueous solution, acid-treated starch, dextrin, etc. To ensure more uniform mixing, it is preferable to stop stirring midway and remove any raw material mixture adhering to the inner walls of the container and the mixer with a spatula or the like, or to use a mixer equipped with a mechanism for removing any adhering raw material mixture.

[0061] When an aqueous dextrin solution is used, the aqueous dextrin solution may be prepared separately from the aqueous alkali solution and added to the mixer, or the alkali and dextrin may be dissolved together in water to prepare an aqueous solution containing the alkali and dextrin, which may then be added to the mixer.

[0062] Specifically, first, the alkali and dextrin are each weighed and dissolved in water to prepare an aqueous solution. Next, the starch raw material and optional acid-treated starch are each weighed and added to a mixer. Next, while stirring the starch raw material and optional acid-treated starch in the mixer, the aqueous solution is added and further stirred. Next, the edible oil or fat is added and further stirred. In this case, too, to ensure more uniform mixing, it is preferable to stop stirring midway and remove any raw material mixture adhering to the inner wall of the container and the mixer with a spatula or the like, or to use a mixer equipped with a mechanism for removing any adhering raw material mixture.

[0063] As described above, the components are mixed until uniform, to prepare a raw material mixture having a water content of 20 parts by mass or more and 35 parts by mass or less per 100 parts by mass of the raw material mixture.

[0064] <Step (b)> In step (b), a raw material mixture having a water content of 20 parts by mass or more and 35 parts by mass or less is heat-treated as is. In the second embodiment, the raw material mixture is also heat-treated to a temperature of 120°C or more and 150°C or less without undergoing a dehydration treatment step between steps (a) and (b) to reduce the water content to less than 1 part by mass per 100 parts by mass of the raw material mixture, thereby preventing loss of and thermal damage to the starch raw material and auxiliary raw material components that accompanies the dehydration treatment.

[0065] The temperature for the heat treatment is up to a temperature at which the raw material mixture is heated to 120°C or higher and 150°C or lower, preferably a temperature at which the raw material mixture is heated to 120°C or higher and 145°C or lower, more preferably a temperature at which the raw material mixture is heated to 125°C or higher and 145°C or lower, and even more preferably a temperature at which the raw material mixture is heated to 125°C or higher and 140°C or lower.

[0066] The heat treatment method is not particularly limited as long as it can heat-treat a raw material mixture having a moisture content of 20 parts by mass or more and 35 parts by mass or less at the above-mentioned temperature, and various heating / drying devices can be used, such as a tray-type hot air circulation dryer (hereinafter also referred to as a "tray-type dryer"), a tabletop heating / stirring machine, an airflow dryer, a band ventilation dryer, a fluidized bed dryer, a rotary dryer, a disk dryer, a cylindrical dryer, and an inverted cone mixer dryer.

[0067] When heat-treating in a tray-type hot air circulation dryer, the raw material mixture is spread evenly on a tray, and the tray is placed in a temperature-controlled dryer for heat treatment. It is preferable to stir the mixture over time and perform sampling to ensure uniform heat treatment. The heating time is preferably 1 hour to 6 hours, more preferably 1 hour to 4 hours, and even more preferably 2 hours 30 minutes to 3 hours 30 minutes. After completion of the heat treatment, the mixture is cooled. If necessary, a holding time may be set at the heat treatment temperature. The holding time is preferably 0.5 hours to 5 hours, more preferably 0.5 hours to 3 hours, and even more preferably 0.5 hours to 1 hour. The completion of the heat treatment can be determined by viscosity measurement (breakdown).

[0068] When heat treatment is performed using a tabletop heating and stirring machine, the temperature of the raw material mixture can be raised quickly by setting the pot to the set temperature, and uniform heating can be achieved by stirring the raw material mixture with a stirring blade. However, even in this case, it is preferable to stir and sample the mixture over time to ensure more uniform heat treatment. The heating time is preferably from 1 hour to 6 hours, more preferably from 1 hour to 4 hours, and even more preferably from 2 hours 30 minutes to 3 hours 30 minutes. After the heat treatment is completed, the mixture is cooled.

[0069] As in the first embodiment, steps (a) and (b) may be performed continuously in the same apparatus. For example, steps (a) and (b) can be performed continuously using a powder / granule mixer / dryer equipped with a spiral ribbon impeller in a vertical inverted conical container. Specifically, first, an alkali is weighed and dissolved in water to prepare an alkaline aqueous solution. Next, a starch raw material and one or more selected from the group consisting of acid-treated starch and dextrin are weighed and added to a mixer. Then, stirring and heating of the mixer are initiated. Next, the alkaline aqueous solution is added to the mixer. To ensure a more uniform reaction, it is preferable to add the alkaline aqueous solution at a constant rate. Next, edible oils and fats are added and further stirred. To ensure a more uniform reaction, it is preferable to add the edible oils and fats at a constant rate. Sampling is performed over time, and the mixture is cooled upon completion of the heat treatment.

[0070] When using an aqueous dextrin solution, the aqueous dextrin solution may be prepared separately from the aqueous alkali solution and added to the mixer, or the alkali and dextrin may be dissolved in water to prepare an aqueous solution containing the alkali and dextrin, which may then be added to the mixer.

[0071] Specifically, first, the alkali and dextrin are weighed and dissolved in water to prepare an aqueous solution. Next, the starch raw material and, optionally, the acid-treated starch are weighed and added to a mixer. After that, stirring and heating of the mixer are started. Next, the aqueous solution is added to the mixer. In this case, too, the aqueous solution is preferably added at a constant rate to ensure a more uniform reaction. Next, edible oils and fats are added and further stirred. To ensure a more uniform reaction, the edible oils and fats are preferably added at a constant rate. Sampling is performed over time, and the mixture is cooled once the heat treatment is complete.

[0072] In a second aspect of the present invention, a target starch composition can be obtained by performing steps (a) and (b) as described above. In the present invention, the target starch composition can be obtained without the need for a dehydration step between steps (a) and (b) to reduce the water content of the raw material mixture to less than 1 part by mass per 100 parts by mass of the raw material mixture. Because the dehydration step between steps (a) and (b) is not required, the present invention can prevent the starch raw material, acid-treated starch, dextrin, alkali, and other auxiliary raw material components from leaching into the dehydration solution and reduce the wastewater load caused by the leached components. Furthermore, heat damage to the starch raw material can be minimized by eliminating the need for a dehydration step that employs a drying step. Furthermore, the swelling-inhibiting treatment and the oil / fat processing can be performed simultaneously, simplifying the production process and equipment and improving productivity.

[0073] In the second aspect of the present invention, since the starch composition obtained has been subjected to an oil or fat processing treatment, it is preferable not to carry out steps (c) and (d) described in the first aspect.

[0074] In the second aspect of the present invention, by carrying out steps (a) and (b), a starch composition having similar functions to crosslinked starch, such as less swelling upon heating or heat resistance, can be obtained, and a starch composition having swelling-inhibiting properties can be obtained. According to a preferred aspect, a starch composition having similar functions to crosslinked starch while having a maximum viscosity close to that of the starch raw material can be obtained. Furthermore, a starch composition that not only has swelling-inhibiting properties but has also been subjected to an oil or fat processing can be obtained.

[0075] According to a preferred embodiment of the present invention, the starch composition obtained by this production method has a smooth viscosity when water is added, and its texture and texture do not change much before and after retort, making it retort-resistant. Furthermore, according to a preferred embodiment of the present invention, the starch composition obtained by this production method has little coloration and can be used in a wide range of applications. According to a preferred embodiment of the present invention, by carrying out an oil processing treatment in addition to a treatment that imparts swelling-inhibiting properties, it is possible to improve the texture to a firmer level and add elasticity to the texture of protein-containing products. Furthermore, by carrying out an oil processing treatment, the affinity with oil is increased, thereby also achieving a sedimentation-inhibiting effect of the starch composition. The starch composition obtained by this production method can be preferably used as a starch composition for various foods, such as curry, hash brown, stew, soup, sauce, dressing, processed meat and fish foods, and processed vegetable protein foods.

[0076] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples in any way.

[0077] [1] Preparation of Starch Composition (Part 1) A raw material mixture was prepared using the composition shown in Table 1-1, and heat-treated under the conditions shown in Table 1-2 to obtain a starch composition.

[0078] <Method for preparing starch compositions (using a tray dryer)> 1. First, the alkali and dextrin were weighed and dissolved in distilled water. The amount of water used in the preparation in the table is the amount relative to 100 parts by mass of the starch raw material. 2. Next, the starch raw material was weighed and added to a mixer (Twinbird Corporation's "Food Processor KC-4626"). 3. The mixer was turned on, and the aqueous solution prepared in 1 was added through the inlet. 4. The mixture was stirred in the mixer for approximately 30 to 40 seconds, and starch adhering to the inner walls and blades of the mixer was removed with a spatula or the like. 5. The mixture was stirred again in the mixer for a total of 90 seconds to prepare a raw material mixture. 6. The raw material mixture obtained in 5 was spread on a tray, placed in a tray dryer (Tokyo Rikakikai Co., Ltd. (EYE-LA)'s "WFO-400") adjusted to 150°C, and heat-treated for the time indicated in the table to obtain a starch composition. In the table, the temperature of the raw material mixture at the end of the heat treatment is shown as "product temperature at the end of treatment."

[0079] <Method for preparing starch compositions (using a benchtop heating mixer)> 1. First, the alkali and dextrin were weighed and dissolved in distilled water. Note that the amount of water used in the preparation in the table is the amount per 100 parts by mass of the starch raw material. 2. Next, the starch raw material was weighed and added to a mixer ("Super Mixer" manufactured by Kawata Co., Ltd.). 3. The mixer was turned on, and the aqueous solution prepared in step 1 was added through the inlet. 4. The mixture was stirred in the mixer for approximately 30 to 40 seconds, and starch adhering to the internal walls and blades of the mixer was removed with a spatula or the like. 5. The mixture was stirred again in the mixer for a total of 90 seconds to prepare a raw material mixture. 6. The pot of the benchtop heating mixer ("KR Mini" manufactured by Kajiwara Co., Ltd.) was set to 150°C. The raw material mixture obtained in step 5 was added to this pot and heat-treated for the time indicated in the table, thereby obtaining a starch composition. Note that the temperature of the raw material mixture at the end of the heat treatment is indicated in the table as "Finished Product Temperature."

[0080] <Preparation method of starch compositions of comparative examples> Furthermore, a starch composition was prepared by the method described in Patent Document 2 to obtain Comparative Example 1-1. At this time, the water content in the raw material mixture after dehydration treatment was 50.50 parts by mass per 100 parts by mass of the raw material mixture. The comparative examples other than Comparative Example 1-1 were prepared by the same preparation method as the above-mentioned examples, using the blending and heat treatment conditions shown in Tables 1-1 and 1-2.

[0081] <Viscosity of Starch Composition> The viscosity (RVU) of the obtained starch composition was measured using an "RVA" (Rapid Visco Analyzer) manufactured by New Port Scientific. The "RVA" is an apparatus that can continuously measure viscosity at a programmed temperature and stirrer rotation speed. The viscosity is expressed in units of RVA units (abbreviated as "RVU"), which is approximately equal to the value obtained by dividing the value of Pascal-seconds (Pa.s), a unit of viscosity in the SI unit system, by 0.012. 1. The product and water are mixed in a dedicated aluminum container to prepare a slurry with a dry mass concentration of the product of 6% by mass. A dedicated paddle is placed in the aluminum container and set in the RVA. 2. While measuring the viscosity under stirring at 160 rpm, the temperature is maintained at 40°C for 1 minute, and then the temperature is heated from 40°C to 95°C at a rate of 6°C / min. 3. After maintaining at 95°C for 5 minutes, the sample is cooled to 50°C at a rate of 6°C / min. 4. The viscosity A (cP), which is the maximum viscosity when heated to 95°C, and the viscosity B (cP), which is the minimum viscosity when maintained at 90°C, are read and each viscosity is measured. The breakdown value is calculated by subtracting viscosity B from viscosity A. Furthermore, for the starch compositions obtained in some of the Examples and Comparative Examples, the final viscosity (viscosity at 50°C before retort) and the viscosity after retort were measured using the procedure shown below. 5. The viscosity of the sample from 3 after maintaining it at 50°C for 5 minutes is taken as the final viscosity (viscosity at 50°C before retort). 6. The sample from 5 is transferred to a retort container and subjected to retort treatment (a treatment of maintaining it at 121°C for 20 minutes). 7. The retorted sample from 6 is adjusted to 50°C, transferred again to the RVA's dedicated aluminum container, and set in the RVA. 8. The viscosity after maintaining at 50°C for 6 minutes was defined as the viscosity at 50°C after retorting.

[0082] Each parameter is explained below. From the viewpoint of improving the texture of the food, the maximum viscosity is preferably equal to or higher than the maximum viscosity of the starch raw material. From the viewpoint of the stability of the texture of the food when heated, the smaller the breakdown value, the more suppressed swelling, and the breakdown value is ideally 0. From the viewpoint of improving the texture of the food after retort treatment, the higher the post-retort viscosity, the higher the retort resistance, and in the case of starch raw materials, the viscosity decreases significantly, which affects the texture of the food, so the viscosity should be equal to or higher than the viscosity of the starch raw material before retort.

[0083] <Breakdown inhibition rate> The breakdown inhibition rate is calculated by the inhibition rate of the breakdown value of a starch composition when the breakdown value of the starch raw material is used as the standard. A larger value indicates that swelling during heating is more inhibited. This breakdown inhibition rate value shows a similar tendency regardless of the type of starch raw material. More specifically, the breakdown inhibition rate can be calculated using the following formula. The breakdown inhibition rates of the examples and comparative examples are shown in Table 1-2. Breakdown inhibition rate [%] = ((breakdown value of starch raw material) - (breakdown value of starch composition)) ÷ (breakdown value of starch raw material) × 100

[0084] As shown in Table 1-2, when a starch raw material and dextrin or acid-treated starch were mixed and treated with an alkaline aqueous solution, the breakdown inhibition rate was 45% or more by adjusting the ratio of dextrin or acid-treated starch and the water content (Examples 1-1 to 1-14). On the other hand, the starch composition obtained by dehydration treatment using the preparation method of Patent Document 2 had an extremely low breakdown inhibition rate and no swelling inhibition effect was obtained (Comparative Example 1-1). Furthermore, a sufficient swelling inhibition effect was not obtained with the alkaline solution alone (Comparative Examples 1-2 and 1-3).

[0085] From the viewpoint of improving the texture of the food, the higher the breakdown suppression rate, the better. It is preferably 45% or more, more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more.

[0086] <Maximum viscosity ratio> The maximum viscosity ratio is calculated as the ratio of the maximum viscosity value of the starch composition when the maximum viscosity value of the starch raw material is set to 1, and from the viewpoint of improving the texture of the food, the maximum viscosity ratio is preferably 0.6 or more, more preferably 0.9 or more, and particularly preferably 1 or more. More specifically, the maximum viscosity ratio can be calculated using the following formula. The calculation results obtained are shown in Table 1-2. Maximum viscosity ratio = (maximum viscosity value of the starch composition) ÷ (maximum viscosity value of the starch raw material)

[0087] <Retort Viscosity Ratio> The retort viscosity ratio is calculated as the ratio of the viscosity value at 50°C of the starch composition after retort to the viscosity value at 50°C of the starch raw material before retort. It is required that the processed starch maintains at least the viscosity value at 50°C of the starch raw material before retort after retort treatment. Therefore, from the viewpoint of improving the texture of the food after retort treatment, the retort viscosity ratio is 1 or more, with no particular upper limit. More specifically, it can be calculated using the following formula. The calculation results obtained are shown in Table 2. Retort viscosity ratio = (viscosity value at 50°C of the starch composition after retort) ÷ (viscosity value at 50°C of the starch raw material before retort)

[0088] Table 1-2 shows the results of measurements of breakdown value, breakdown inhibition rate, maximum viscosity value, and maximum viscosity ratio for each Example, Comparative Example, and Control Example. As shown in Table 1-2, by mixing dextrin or acid-treated starch with the starch raw material and treating it with an alkaline aqueous solution, the breakdown value was significantly reduced compared to when dextrin and acid-treated starch were not used (Examples 1-1 to 1-10, Examples 1-13, and 1-14). Furthermore, it was shown that the combined use of dextrin and acid-treated starch achieved a high swelling inhibition effect even when small amounts were added (Examples 1-11 and 1-12). On the other hand, the starch composition obtained by the preparation method involving dehydration treatment described in Patent Document 2 and the starch composition obtained by containing only an alkaline solution did not achieve a sufficient swelling inhibition effect (Comparative Examples 1-1 to 1-3). These results demonstrate that the starch composition produced by the method of the present invention has swelling inhibition function. Waxy corn, used as the starch raw material, is known to have a relatively large breakdown, as shown in Control Example 1-1. As described above, swelling was effectively suppressed when waxy corn was used, and it is expected that the method of the present invention will similarly suppress swelling when other starch raw materials are used.

[0089] <Evaluation of Whiteness of Starch Compositions> The whiteness of each Example and Comparative Example was evaluated visually, using the whiteness of the starch raw material (Control Example 1-1) as a control. Evaluations were performed by three expert panelists, and the evaluation results were obtained by consensus. The evaluation results are shown in Table 1-2. In the table, "◎" (A) indicates a whiteness equivalent to that of the control example, "◯" (B) indicates slight discoloration compared to the control example, and "Δ" (C) indicates significant discoloration compared to the control example. As shown in Table 1-2, even when dextrin or acid-treated starch was mixed with the starch raw material and treated with an alkaline aqueous solution, the discoloration of the starch composition could be suppressed by adjusting the ratio of dextrin or acid-treated starch or the water content (Examples 1-1 to 1-14). In particular, when only acid-treated starch was used, it was shown that a discoloration suppression effect could be obtained while maintaining the swelling suppression effect (Examples 1-9 and 1-10).

[0090] <Water Content of Raw Material Mixture> In Table 1-1, the "water content of raw material mixture" is the amount of water (parts by mass) calculated relative to 100 parts by mass of the raw material mixture, assuming that the water content per 100 parts by mass of each raw material flour is 13 parts by mass for the starch raw material, 13 parts by mass for the acid-treated starch, and 5 parts by mass for the dextrin.

[0091]

[0092] The ingredients in the table are as follows: Waxy corn: "Waxy corn starch" manufactured by J-Oil Mills Co., Ltd. Alkali: Sodium carbonate Dextrin 1 (DE 22-26): "Sandec #250" manufactured by Sanwa Starch Co., Ltd., 15% pentasaccharides, 13% hexasaccharides Dextrin 2 (DE 33): "Tetrap" manufactured by Hayashibara Co., Ltd., 54.2% tetrasaccharides Dextrin 3 (DE 5-7): "FZ-100" manufactured by Maruzen Pharmaceuticals Co., Ltd., containing dextrin and waxy corn Dextrin 4 (DE approximately 50): "Sunmalto S" manufactured by Hayashibara Co., Ltd., 92% or more disaccharides Dextrin 5 (DE approximately 38): Puretose L (Gunei Chemical Co., Ltd.), 55% or more trisaccharides Acid-treated starch (number average molecular weight: approximately 320,000): 80 parts by mass of 6% by mass hydrochloric acid was added to 320 parts by mass of an aqueous dispersion of 40% by mass waxy cornstarch (manufactured by J-Oil Mills Co., Ltd.), and the mixture was stirred at 40° C. for 24 hours to perform an acid treatment. After the acid treatment, the mixture was neutralized with slaked lime to a pH of 5, and then washed and dried to obtain an acid-treated starch.

[0093] The viscosity at 50°C of Examples 1-6, 1-8, and 1-13, and Comparative Examples 1-2 and 1-3 was measured before and after retorting, and compared with that of Control Example 1-1. The results are shown in Table 2. As shown in Table 2, it was suggested that mixing dextrin or acid-treated starch with a starch raw material and treating the mixture with an alkaline aqueous solution can impart retort resistance compared to a case in which dextrin or acid-treated starch is not used. It was also suggested that using a dextrin with a DE value of less than 50 results in a retort viscosity ratio of 1 or more, and thus allows for the production of a starch composition with superior retort resistance (Examples 1-6 and 1-8).

[0094]

[0095] [2] Preparation of starch compositions (part 2) A raw material mixture was prepared using the composition shown in Table 3-1, and heat-treated under the conditions shown in Table 3-2 to obtain starch compositions. The method for preparing the starch compositions was the same as the method described in [1] above. Each of the obtained starch compositions was washed and dehydrated or dried as follows to obtain washed starch compositions.

[0096] <Washing and dehydration / drying treatment of starch composition> The starch composition was dissolved in a 5-fold amount of water using a stirrer, and the pH was adjusted with a pH adjuster to a range of preferably 4 or more and 7 or less, more preferably 5 or more and 7 or less, and even more preferably 5 or more and 6 or less to obtain a pH-adjusted slurry. The obtained pH-adjusted slurry was subjected to dehydration or drying treatment to obtain a washed starch composition. The amount of water used during preparation in the table is the amount per 100 parts by mass of the starch raw material.

[0097] The viscosity of the resulting washed starch composition was measured in the same manner as described in [1] above, and the breakdown value, breakdown inhibition rate, maximum viscosity value, and maximum viscosity ratio are shown in Table 3-2. The breakdown value, breakdown inhibition rate, maximum viscosity value, and maximum viscosity ratio of waxy corn are also shown in the table as Control Example 2-1. As shown in Table 3, a high swelling inhibition effect was achieved by performing the washing treatment (Examples 2-1 to 2-12). It was also shown that the combined use of dextrin and acid-treated starch could achieve a high swelling inhibition effect even when small amounts of these were added (Examples 2-6 to 2-12).

[0098]

[0099] The ingredients in the table are as follows. Waxy corn: "Waxy corn starch" manufactured by J-Oil Mills Co., Ltd. Alkali: Sodium carbonate Dextrin 1 (DE 22-26): "Sandec #250" manufactured by Sanwa Starch Co., Ltd., 15% pentasaccharide, 13% hexasaccharide Acid-treated starch (number average molecular weight approximately 320,000): An acid treatment was carried out by adding 80 parts by mass of 6% by mass hydrochloric acid to 320 parts by mass of an aqueous dispersion of 40% by mass waxy corn starch (manufactured by J-Oil Mills Co., Ltd.) and stirring at 40°C for 24 hours. After the acid treatment, the mixture was neutralized with slaked lime to a pH of 5, followed by washing and drying to obtain an acid-treated starch.

[0100] For Examples 2-1 to 2-12, the viscosity of the starch compositions at 50°C before and after retort was measured in the same manner as described in [1] above, and the results were compared with those of Control Example 2-1. The results are shown in Table 4. As shown in Table 4, it was suggested that the retort resistance was improved by the washing treatment (Examples 2-1 to 2-12). Furthermore, the starch compositions that showed a high swelling-inhibiting effect due to dextrin and acid-treated starch maintained their viscosity even after retort, indicating that they had retort resistance (Examples 2-6 to 2-9, 2-12).

[0101]

[0102] Furthermore, the whiteness of the starch compositions of Examples 2-6 and 2-10 was evaluated in the same manner as described in [1] above, using the whiteness of Control Example 2-1 as a control. The results are shown in Table 5. As shown in Table 5, it was clear that the washing treatment resulted in less discoloration than the control example.

[0103]

[0104] [3] Preparation of Starch Composition (Part 3) A raw material mixture was prepared using the composition shown in Table 6-1, and heat-treated under the conditions shown in Table 6-2 to obtain a starch composition. The method for preparing the starch composition was the same as the method described in [1] above, except that an oil or fat was added. In the example where a powder and granular material mixer and dryer, "Ribocone" manufactured by Okawara Seisakusho Co., Ltd., was used, the starch composition was prepared as follows.

[0105] <Method for preparing starch composition (using powder and granular mixer and dryer)> 1. First, the alkali and dextrin were weighed and dissolved in distilled water, and the oil and fat were weighed. The amount of water used during preparation in the table is the amount relative to 100 parts by mass of the starch raw material. 2. The starch raw material and acid-treated starch were weighed into the powder and granular mixer and dryer body, and stirring and heating were initiated. 3. The aqueous solution prepared in 1 and the oil and fat were fed into the feed port at a constant rate. 4. Subsequently, the oil and fat were fed into the feed port at a constant rate. 5. Sampling was carried out over time. 6. After heating was completed, the mixture was cooled.

[0106] The viscosity of the obtained starch compositions was measured in the same manner as described in [1] above, and the breakdown value and maximum viscosity value are shown in Table 6-2. As shown in Table 6-2, even when fats or oils were added, the breakdown value decreased by mixing dextrin or acid-treated starch with the starch raw material and treating the mixture with an alkaline aqueous solution, and starch compositions having swelling-inhibiting properties were obtained (Examples 3-1 to 3-8).

[0107]

[0108] The ingredients in the table are as follows. Regular corn: "Corn starch" manufactured by J-Oil Mills, Inc. Waxy corn: "Waxy corn starch" manufactured by J-Oil Mills, Inc. Alkali: Sodium carbonate Dextrin 1 (DE 22-26): "Sandec #250" manufactured by Sanwa Starch Industry Co., Ltd., 15% pentasaccharide, 13% hexasaccharide Acid-treated starch (number average molecular weight approximately 320,000): 80 parts by mass of 6% by mass hydrochloric acid was added to 320 parts by mass of an aqueous dispersion of 40% by mass waxy corn starch (manufactured by J-Oil Mills, Inc.), and the mixture was stirred at 40°C for 24 hours to perform an acid treatment. After the acid treatment, the mixture was neutralized with slaked lime to a pH of 5, followed by washing and drying to obtain an acid-treated starch. Oils and fats: High linol safflower oil, "Safflower salad oil" manufactured by Summit Oil Mills, Inc.

[0109] [4] Evaluation of Starch Compositions (Part 1) Next, sauces were prepared using the starch compositions obtained in Examples 2-11 and 2-12 according to the following procedure, and the taste of the sauces was compared with that of existing products.

[0110] <Preparation of Sauce> 1. The ingredients listed in Table 7 were weighed into a pot, and the pot was placed on the fire and heated until the evaporated water had evaporated. After heating, the pot was cooled to prepare the sauce. 2.1 100 g of the sauce was transferred to a retort pouch, and the remainder was transferred to a container for tasting. 3.2 The retort pouch was retorted in a retort sterilizer (HLM-36LBC, manufactured by Hirayama Seisakusho Co., Ltd.) at 121°C for 20 minutes.

[0111]

[0112] <Evaluation of sauce> The taste before and after retort processing was evaluated using the following evaluation criteria. The results are shown in Table 8. 1) Viscosity ◎ (A): Sufficient viscosity for a sauce ○ (B): Viscous △ (C): Low viscosity × (D): No viscosity, runny 2) Unpleasant taste or odor Check for the presence or absence of an unpleasant taste or odor (yes or no). 3) Roughness Check for an unpleasant rough feeling when eating the sauce (yes, slightly, or no) 4) Texture ・Long: Stringy and very viscous ・Short: Not stringy and not very viscous

[0113]

[0114] The following existing products were used: "Novation 2600": waxy cornstarch, manufactured by Ingredion Inc. "A-15": acetylated phosphate cross-linked waxy cornstarch, manufactured by J-Oil Mills Co., Ltd.

[0115] [5] Evaluation of Starch Compositions (Part 2) Batters for fried foods were prepared using the starch compositions obtained in Examples 3-3 to 3-8 according to the following procedure. Pork loin was coated with this batter and adjusted to a rich texture, and the texture was evaluated using an existing product as a control.

[0116] <Preparation of Batter> Batter was prepared according to the composition shown in Table 9.

[0117] The ingredients in the table are as follows: Gum mix: 4% xanthan gum (manufactured by DSP Gokyo Food & Chemical Co., Ltd., "Echo Gum F"), 96% cornstarch (manufactured by J-Oil Mills Co., Ltd., "Cornstarch Y")

[0118] <Breading> The pork loin was breaded using the following procedure. 1. The breadcrumbs, which had been brought to room temperature, were placed in a tray. 2. The batter was transferred to a bowl and the pork loin was dipped in the batter. 3. The pork loin from step 2 was transferred to step 1 and breaded. 4. 3 was arranged in plastic wrap, wrapped, placed on a tray and frozen in the refrigerator overnight or longer.

[0119] <Frying> Breaded pork loin was fried at 170°C for 4 to 5 minutes. After 2 minutes, it was turned over and removed after 4 minutes when it had floated to the surface. After allowing it to cool for about 1 minute, it was cut into 4 equal pieces and the adhesion of the batter was evaluated.

[0120] <Evaluation of adhesiveness> The adhesiveness of the batter after frying was evaluated according to the following evaluation criteria. The results are shown in Table 10. 1) Visual degree of peeling (adhesiveness score) ◯ (A): Not peeled Δ (B): Partially peeled × (C): More than 30% peeled The adhesiveness score was calculated and evaluated using the following formula. A higher score indicates better adhesiveness. Score = ((number of ◯) × 1 + (number of Δ) × 0.5 + (number of ×) × 0) / total number of evaluations × 100 2) Ease of peeling when touched (degree of peeling) ⊚ (A): Very difficult to peel ◯ (B): Difficult to peel Δ (C): Somewhat easy to peel × (D): Easy to peel 3) Texture The hardness, stickiness, crispness, flavor, and other unpleasant sensations were evaluated comprehensively.

[0121]

[0122] The following existing products were used: "HB-310": food-grade modified starch, including corn starch, manufactured by J-Oil Mills Co., Ltd. "HB-150": food-grade modified starch, including soybean flour and tapioca starch, manufactured by J-Oil Mills Co., Ltd.

[0123] <Method for measuring Brookfield viscosity> The Brookfield viscosity (cP (mPa s)) of the starch compositions used in the above examples was measured using the following procedure. 1. Powders (90 g of starch composition, 9.6 g of xanthan gum (manufactured by DSP Gokyo Food & Chemical Co., Ltd., "Echo Gum F"), and 0.4 g of cornstarch (manufactured by J-Oil Mills Co., Ltd., "Corn Starch Y") were weighed into a 250 mL beaker and mixed with a spatula. 2. 200 g of cold water was added to the beaker in 1 and stirred with a spatula. 3. The mixture in 2 was stirred at 3000 rpm using a homogenizer. The mixture was stirred using the spatula until no lumps remained. 4. After allowing to stand in surface water for 5 minutes, the Brookfield viscosity was measured. The measurement was performed using a Brookfield viscometer (manufactured by Tokyo Keiki Inc., BM model, No. 3 rotor) at a rotation speed of 30 rpm. The value was read at the 15th rotation (after 30 seconds) and is shown in Table 11.

[0124]

[0125] As shown in Tables 10 and 11, the starch compositions obtained according to the present invention did not significantly affect the viscosity of the batter when incorporated into the batter, exhibited sufficient binding properties, and the resulting fried foods had a good texture. In particular, when the starch composition of Example 3-5 was used, the composition exhibited binding properties equivalent to those of the existing product "HB-310" using the same starch raw material, while imparting crispness, suppressing stickiness, and providing a good flavor and texture superior to that of the existing product. Furthermore, it was suggested that the stickiness and stickiness of foods could be reduced by reducing the content of acid-treated starch to less than 8 parts by mass (Examples 3-4 and 3-8).

[0126] From the above results, it was shown that by heat-treating acid-treated starch and starch hydrolysates such as dextrin with an alkaline agent at an appropriate water content, a starch composition (food material) that is heat-resistant and has texture improvements such as a pleasant texture on the tongue can be obtained using simplified equipment. Furthermore, it was also shown that oil and fat processing can be carried out in the same process, and a starch composition (food material) with improved texture can be obtained.

Claims

1. A method for producing a starch composition, comprising: (a) preparing a raw material mixture containing a starch raw material, one or more selected from the group consisting of acid-treated starch and dextrin, and an aqueous alkali solution, the raw material mixture having a water content of 20 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of the raw material mixture; and (b) heat-treating the raw material mixture having a water content of 20 parts by mass or more and 35 parts by mass or less obtained in step (a) to a temperature of 120°C or more and 150°C or less. The method for producing the starch composition as described above.

2. The method for producing a starch composition according to claim 1, wherein the mass ratio of the starch raw material with respect to 100 parts by mass of the raw material mixture is 56 parts by mass or more and 79 parts by mass or less.

3. The method for producing a starch composition according to claim 1 or 2, wherein the mass ratio of the acid-treated starch with respect to 100 parts by mass of the raw material mixture is 0.5 parts by mass or more and 20 parts by mass or less.

4. The method for producing a starch composition according to any one of claims 1 to 3, wherein the mass ratio of the dextrin with respect to 100 parts by mass of the raw material mixture is 0.1 parts by mass or more and 20 parts by mass or less.

5. The method for producing a starch composition according to any one of claims 1 to 4, wherein the number average molecular weight of the acid-treated starch is 250,000 or more and 500,000 or less.

6. The method for producing a starch composition according to any one of claims 1 to 5, wherein the DE (degree of decomposition) of the dextrin is 5 or more and less than 50.

7. The method for producing a starch composition according to any one of claims 1 to 6, wherein the dextrin is an aqueous dextrin solution.

8. The method for producing a starch composition according to any one of claims 1 to 7, wherein the alkali used in the aqueous alkali solution is one or more selected from the group consisting of calcium hydroxide, sodium carbonate, calcium carbonate, potassium carbonate, sodium bicarbonate, and dipotassium hydrogen phosphate.

9. The method for producing a starch composition according to any one of claims 1 to 8, which does not require a dehydration treatment step for the water content of the raw material mixture to be less than 1 part by mass with respect to 100 parts by mass of the raw material mixture between steps (a) and (b).

10. The method for producing a starch composition according to any one of claims 1 to 9, wherein the raw material mixture further contains an edible oil and fat.

11. The method for producing a starch composition according to claim 10, wherein the mass ratio of the edible oil and fat to 100 parts by mass of the raw material mixture is 0.05 part by mass or more and 1.5 parts by mass or less.

12. The method for producing a starch composition according to any one of claims 1 to 9, further comprising: (c) a step of adding water and a pH adjuster to the heat-treated product obtained in step (b) and performing a washing treatment; and (d) a step of dehydrating or drying the washed product obtained in step (c).