WO2025121232A1 - Method for producing modified resistant starch - Google Patents

Abstract

The present invention addresses the problem of providing a modified resistant starch which provides improvement to rough texture that is a problem peculiar to food containing a resistant starch, and which, when used for food that is intended to be low in carbohydrates, does not compromise the smooth and palatable texture inherent in said food. A method for producing a modified resistant starch according to the present invention comprises a step for adding 5-75 parts by mass of water to 100 parts by mass of a resistant starch and heating the resistant starch. As a result of the step, the average particle diameter of the resistant starch after being heated becomes 1.20-1.50 times of the average particle diameter of the resistant starch before being heated.

Description

Method for producing modified resistant starch

The present invention relates to technology for improving resistant starch.

Carbohydrates are one of the three major nutrients, along with lipids and proteins. However, consuming large amounts of carbohydrates can contribute to an increase in body fat, and if a large amount of carbohydrate is consumed, blood sugar levels rise, which can become a risk factor for diabetes. For this reason, there has been an increasing demand for low-carbohydrate foods in recent years.

Dough foods such as bakery foods and noodles are typically produced using dough, which is a mixture of powdered ingredients such as flour and starch, and liquid ingredients such as water, as an intermediate product, and contain a lot of carbohydrates. Therefore, in order to reduce the carbohydrate content of dough foods, the grain flour (carbohydrates) contained in dough foods has traditionally been replaced with dietary fiber, and resistant starch, resistant dextrin, inulin, and the like have been used as such dietary fiber. However, when dietary fiber is added to dough foods, there is a problem in that the dough foods develop a rough texture, which reduces the taste and texture, and impairs the palatability of the food. This tendency is more pronounced when resistant starch is used.

Patent Document 1 describes a method for producing dietary fiber starch, which is starch with a total dietary fiber content of 50% or more, which includes a process of heat-treating starch at a temperature below the gelatinization temperature, phosphorylating it, and then heat-treating it again at a high temperature, and describes heat-treating conditions for the phosphorylated starch as heat-treating it at a temperature above the gelatinization temperature, 80 to 95°C, with shaking for 1 to 30 minutes. Patent Document 2 describes another method for producing the dietary fiber starch, which includes a process of carrying out high-temperature heat treatment and ultrasonic treatment while cross-linking rice starch, and describes high-temperature heat-treating conditions as heat-treating it with vibration at 80 to 95°C for 1 to 10 minutes. The manufacturing methods described in Patent Documents 1 and 2 were developed in consideration of the problem that when modified starch such as phosphate-crosslinked starch is applied to liquid foods such as mayonnaise, it tends to separate due to its low emulsifying power, and it is said that this manufacturing method produces dietary fiber starch with enhanced emulsifying power.

Patent Document 3 describes yet another method for producing the dietary fiber starch, which includes a step of phosphorylating and moist heat treating starch, followed by a further moist heat treatment, and describes conditions for the latter moist heat treatment (i.e., moist heat treatment of phosphorylated starch) in which the moisture content of the starch to be treated is adjusted to about 10-80% by weight relative to the weight of the starch in a dry state, and then heat treating at a temperature of about 65-160°C for 0.25-24 hours. The production method described in Patent Document 3 was made in consideration of the problem that the dietary fiber content is significantly reduced when dietary fiber starch is subjected to extrusion processing using an extruder, and it is said that this production method produces dietary fiber starch that can maintain a total dietary fiber content of 50% or more even after extrusion processing.

US Patent Application Publication No. 2012/0132197 US Patent Application Publication No. 2011/0129579 European Patent No. 1836903

The object of the present invention is to provide a modified resistant starch that improves the rough texture that is a particular problem with foods that contain resistant starch, and that does not impair the food's inherent smooth, pleasant texture when used in foods to reduce sugar content.

The present invention is a method for producing a modified resistant starch, which includes a step of adding 5 to 75 parts by mass of water to 100 parts by mass of resistant starch and then heat-treating the resistant starch, and by this step, the average particle size of the resistant starch after the heat treatment is 1.20 to 1.50 times the average particle size of the resistant starch before the heat treatment.

In the production method of the present invention, resistant starch is used as the main raw material.
Resistant starch is a type of dietary fiber that is difficult to digest with digestive enzymes. In this specification, "dietary fiber" refers to a food ingredient that is not digested by human digestive enzymes. Starch is a polymer in which glucose is bound in large numbers through α(1,4) bonds and α(1,6) bonds, and starch derived from living organisms is generally decomposed by digestive enzymes. However, even if derived from living organisms, starch that has a specific structure in part or in its entirety or starch that has been chemically modified becomes resistant to digestive enzymes.

In general, resistant starch is classified into four types, RS1 to RS4, as follows.
RS1 is a type of resistant starch that is resistant to digestion because, although the starch itself is easily digested, it is physically protected by an outer skin or the like and cannot be acted on by digestive enzymes. It is mainly found in whole grain flour, seeds, legumes, etc.
RS2 is a type of resistant starch that exhibits resistance to digestion due to the special crystal structure of the starch granules, and examples of this include potato starch that has been subjected to moist heat treatment under low moisture conditions and unripe banana starch. High amylose starch also contains a large amount of amylose with a linear structure and is classified as RS2.
RS3 is a resistant starch that exhibits resistance to digestion due to a change in structure caused by retrogradation of starch, which makes it difficult for digestive enzymes to act on it. An example of RS3 is retrograded starch (beta-starch) that is obtained by first gelatinizing (gelatinizing) the starch by heating and then cooling it.
RS4 is a resistant starch that is highly chemically modified and thus exhibits resistance to digestion, and examples of such starch include cross-linked starch that has been subjected to a strong cross-linking treatment, and etherified and/or esterified starch.

The resistant starch used in the present invention may be natural starch (unprocessed starch) or processed starch. The source of the resistant starch is not particularly limited, and it may be derived from any plant, such as tapioca starch or potato starch.
In the present invention, the resistant starch may be one selected from the above-mentioned RS1 to RS4, or two or more of them may be used in combination.

As is clear from the above explanation of RS1 to RS4, resistant starch may contain impurities (substances that cannot be completely removed by refining the resistant starch). From the viewpoint of ensuring that foods are low in carbohydrates and enriched with dietary fiber, the resistant starch used in the present invention preferably contains few impurities, i.e., has a high purity. More specifically, the resistant starch used in the present invention preferably has a dietary fiber content of 75% by mass or more calculated as starch dry matter.
The above-mentioned RS4, particularly phosphate-crosslinked starch, is preferred because its dietary fiber content is increased by chemical modification (such as phosphate crosslinking) under appropriate conditions to obtain it. Many RS4, particularly phosphate-crosslinked starches, have a dietary fiber content of 75% by mass or more calculated as starch dry matter. The term "phosphate-crosslinked starch" as used herein refers to processed starch that has been subjected to at least phosphate crosslinking treatment, and may also be subjected to processing other than phosphate crosslinking treatment (e.g., gelatinization).

In this specification, "dietary fiber content" is a value quantified based on AOAC2011.25. For example, the dietary fiber content can be measured using a commercially available measurement kit, such as a dietary fiber measurement kit (Wako Pure Chemical Industries, Ltd.).

In the present invention, commercially available products can be used as the raw material resistant starch. For example, commercially available RS2 products include Nisshoku Roadster (manufactured by Nihon Shokuhin Kako Co., Ltd.), Himaze 1043 (manufactured by Nippon NSC Co., Ltd.), and Actistar 11700 (manufactured by Cargill Japan Co., Ltd.). Commercially available RS4 products include Pine Starch RT (manufactured by Matsutani Chemical Industry Co., Ltd.), Novelose (manufactured by Ingredion Inc.), Fibergym RW (manufactured by Matsutani Chemical Industry Co., Ltd.), and Actistar RT 75330 (manufactured by Cargill Japan Co., Ltd.).

The form of the resistant starch is not particularly limited, and may be what is generally referred to as powder, fine grains, granules, etc. Furthermore, the particle size of the resistant starch is not particularly limited, and may be appropriately selected depending on the application of the resulting modified resistant starch. For example, from the viewpoint of the balance between the handleability of the modified resistant starch and the texture of the food using it, the average particle size of the resistant starch used as a raw material is preferably 5 to 30 μm, more preferably 15 to 25 μm.

In this specification, the "average particle size" refers to the particle size at which the cumulative amount accumulates to 50% from the smallest particle in the cumulative particle size distribution curve of the volume-based resistant starch measured by the dry laser diffraction/scattering method. The average particle size can be measured in accordance with standard methods using, for example, a commercially available laser diffraction particle size distribution measuring device (e.g., Microtrac MT3300EXII, manufactured by Nikkiso Co., Ltd.).

The manufacturing method of the present invention includes a step of adding 5 to 75 parts by mass, preferably 15 to 65 parts by mass, and more preferably 25 to 55 parts by mass of water to 100 parts by mass of resistant starch, and then heat-treating the resistant starch. The resistant starch that has undergone this step is the modified resistant starch that is the product of the present invention.

In the heat treatment, the moisture added to the treatment target (resistant starch) may be in the form of a liquid or gas, and examples thereof include water, saturated steam, and superheated steam.
Examples of the heating method in the heat treatment include 1) a method in which a heat medium such as hot air is directly brought into contact with the treatment target (resistant starch), and 2) a method in which the treatment target is indirectly heated in a high humidity atmosphere. The apparatus for carrying out the heat treatment is not particularly limited, and examples thereof include a kiln, an autoclave, a steam oven, and a single-screw or twin-screw extruder. One example of the heat treatment includes a method in which the treatment target is added with water, sealed thinly and flat in a sealed container such as an aluminum pouch, and heated together with the sealed container in a kiln, an oil heater, an oil bath, an autoclave, or the like. Another example of the heat treatment includes a method in which the treatment target is added with water, introduced into a sealed container, and then heated under pressure by introducing saturated steam into the container while stirring the treatment target as necessary.

In the production method of the present invention, the heat treatment makes the average particle size of the resistant starch after the heat treatment (modified resistant starch) 1.20 to 1.50 times, preferably 1.25 to 1.45 times, and more preferably 1.25 to 1.40 times, the average particle size of the resistant starch before the heat treatment.
Hereinafter, the "ratio of the average particle size of the resistant starch after heat treatment to the average particle size of the resistant starch before heat treatment" will also be referred to as the "average particle size increase ratio."
The modified resistant starch obtained by the production method of the present invention solves the problems associated with conventional resistant starches, and when used in foods, it has the effect of not impairing the food's inherent smooth texture with a pleasant feel in the mouth.
If the average particle size increase ratio is less than 1.20 times or more than 1.50 times, the effect of improving the rough texture caused by resistant starch in foods containing resistant starch is poor.
The average particle size increase ratio can be adjusted by appropriately adjusting the conditions of the heat treatment (eg, the amount of water added, the heating temperature, and the heating time).

In the manufacturing method of the present invention, typically, the starting starch (resistant starch) is subjected to the heat treatment once before obtaining the modified resistant starch to be manufactured. For example, in the manufacturing method described in Patent Document 3, the starting starch is subjected to two heat treatments (moist heat treatments) before obtaining the dietary fiber starch to be manufactured. However, when the starting starch is subjected to multiple heat treatments in this manner, it becomes difficult to control the average particle size increase rate, and there is a risk that the desired effect of the present invention will not be achieved.

The average particle size of the resistant starch after the heat treatment, i.e., the modified resistant starch, is not particularly limited, but is preferably 6 to 45 μm, more preferably 17.5 to 37.5 μm, provided that the average particle size increase ratio is 1.20 to 1.50, depending on factors such as the average particle size of the resistant starch before the heat treatment.

In order to ensure that the effects of the heat treatment are more effectively achieved, the product temperature (heating temperature) of the treatment target (resistant starch with added moisture) in the heat treatment is preferably 120 to 220°C, more preferably 165 to 220°C, and the time (heating time) during which the product temperature is maintained is preferably 5 to 60 minutes, more preferably 5 to 30 minutes.

In the manufacturing method of the present invention, the modified resistant starch obtained through the heat treatment may be subjected to post-treatment such as drying and pulverization, if necessary. The drying is a treatment for reducing the moisture content of the modified resistant starch, and can be carried out by appropriately using a known drying method such as air drying or hot air drying. The pulverization can be carried out in the usual manner using a known pulverization means such as a pin mill or roll mill.

The ratio of the dietary fiber content, calculated as a dry mass, of the modified resistant starch (the resistant starch after the heat treatment) to the dietary fiber content, calculated as a dry mass of the resistant starch before the heat treatment (hereinafter also referred to as the "dietary fiber content change rate") is preferably 0.90 or more, more preferably 0.92 or more, from the viewpoint of allowing a sufficient amount of dietary fiber to be contained in a food using the modified resistant starch of the present invention. Moreover, the upper limit of the dietary fiber content change rate is preferably 0.99 or less, more preferably 0.98 or less, from the viewpoint of preventing deterioration in texture due to an excess of dietary fiber in a food using the modified resistant starch of the present invention.
The rate of change in dietary fiber content can be adjusted by appropriately adjusting the conditions of the heat treatment (eg, amount of water added, heating temperature, heating time, etc.).

The modified resistant starch obtained by the production method of the present invention can be used in various foods, and is particularly useful as an ingredient for reducing the sugar content of dough foods.
In this specification, "dough food" refers to a food produced by forming an intermediate product, which is a mixture of powdered ingredients such as flour and starch and liquid ingredients such as water, into a predetermined shape, and then heating the dough. The "dough" referred to here includes clay-like dough (so-called dough) and liquid or paste-like dough (so-called batter). Specific examples of dough foods include bakery foods, noodles, and fried foods with batter.

In this specification, "bakery food" refers to food obtained by adding liquid ingredients such as water to cereal flour (flour, starch) as the main ingredient, and further mixing with auxiliary ingredients such as yeast or leavening agents (baking powder, etc.), salt, sugar, etc. as necessary, to obtain a fermented or unfermented dough, which is then subjected to heat treatment such as baking, steaming, or deep frying. Specific examples of bakery food include breads; pizzas; cakes; Japanese and Western baked goods such as waffles, choux pastries, biscuits, dorayaki, and baked buns; steamed sweets; fried sweets such as donuts and corn dogs; and snacks such as okonomiyaki, takoyaki, chijimi, and negiyaki. Specific examples of cakes include sponge cake, butter cake, roll cake, hotcake, bussee, baumkuchen, pound cake, cheesecake, snack cake, muffin, bar, cookie, crepe, and pancake.

In this specification, "noodles" refers to foods made by kneading a dough made primarily from grain flour (grain flour, starch) to which liquid ingredients such as water have been added, and further mixing and kneading auxiliary ingredients such as salt as necessary, and then 1) rolling or stretching the dough to obtain a noodle sheet dough, which is then stretched, cut, punched, etc., or 2) extrusion-molded into a specific shape such as a noodle string. Specific examples of noodles include soba, udon, hiyamugi, Chinese noodles, spaghetti, macaroni, ravioli, and noodle skins.

In this specification, "fried foods with batter" refers to foods obtained by adding liquid ingredients such as water to cereal flour (flour, starch) as the main ingredient, and optionally adding auxiliary ingredients such as leavening agents (baking powder, etc.), salt, sugar, soy sauce, and garlic to obtain a liquid batter, which is then applied to the surface of ingredients and subjected to a heat treatment such as frying or baking. Specific examples of fried foods with batter include tempura, karaage, tatsuta-age, and fritters.

The modified resistant starch obtained by the manufacturing method of the present invention (hereinafter, simply referred to as "modified resistant starch") can be used in the same manner as various dough ingredients that are mixed into dough foods. For example, in the manufacture of dough foods that use batter, such as cakes and fried foods with batter, the modified resistant starch may be mixed in at the beginning of dough preparation, or may be mixed in the dough after preparing the dough using other powder ingredients and liquid ingredients. For example, in the manufacture of bread by the straight method, or in the manufacture of dough foods that use dough, such as noodles and cookies, it is preferable to mix the modified resistant starch in the same manner as the dough ingredients that are used first, such as wheat flour, at the beginning of dough preparation (for example, before the addition of liquid ingredients). For example, in the manufacture of bread by the sponge method, the modified resistant starch may be mixed as a sponge ingredient before sponge fermentation, or may be mixed in the main kneading ingredient.

The modified resistant starch may also be incorporated into a mix for dough foods (hereinafter simply referred to as a "mix"). The content of the modified resistant starch in the mix can be adjusted appropriately depending on the use of the mix, and is not particularly limited. For example, when the dough foods produced using the mix are the aforementioned bakery foods, noodles, or fried foods with batter, the content of the modified resistant starch is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total mass of the mix, from the viewpoint of the balance between the effects of the modified resistant starch (reducing the sugar content of the dough foods, etc.) and the taste and texture of the dough foods.

The mix typically contains one or more types of cereal flour other than the modified resistant starch. In this specification, the term "cereal flour" refers to a substance that is powdery at room temperature and pressure derived from a grain, and is a concept that includes cereal flour and starch. Unless otherwise specified, "starch" refers to "pure starch" isolated from plants such as wheat, and is distinguished from starch that is inherently present in cereal flour.
Examples of flour include wheat flour (strong flour, semi-strong flour, medium flour, weak flour, durum wheat flour, whole wheat flour), buckwheat flour, rice flour, corn flour, barley flour, rye flour, pearl barley flour, barley flour, and foxtail millet flour.
Examples of starch include unprocessed starches such as tapioca starch, potato starch, corn starch, waxy corn starch, wheat starch, and rice starch; and processed starches obtained by subjecting the unprocessed starches to one or more treatments such as gelatinization, etherification, esterification, acetylation, crosslinking, and oxidation.

The total content of cereal flours, including modified resistant starch, in the mix can be adjusted appropriately depending on the use of the mix, etc., and is not particularly limited. For example, when the dough food produced using the mix is the aforementioned bakery food, noodles, or fried food with batter, the total content of the flours is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, based on the total mass of the mix.

The mix may contain, in addition to the grain flour, other ingredients as necessary, such as emulsifiers such as glycerin fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, lecithin, organic acid monoglycerides, sodium stearoyl lactylate, and calcium stearoyl lactylate; protein materials such as gluten, gliadin, and glutenin (all wheat proteins), skim milk powder, whey protein (all milk proteins), soy protein, and gelatin; fats and oils such as animal fats and vegetable fats; salt, powdered soy sauce, fermented products such as fermented products derived from fruits, powdered miso paste, amino acids, and other seasonings; dried eggs such as egg powder; sugars, sweeteners; thickening polysaccharides, leavening agents, dairy ingredients, flavorings, enzymes, and colorings. These may be used alone or in combination of two or more. The content of ingredients other than grain flour in the mix may be appropriately adjusted depending on the purpose of the mix.

The mix can be used as a powder ingredient when producing dough foods. For example, a method for producing bakery foods or noodles using the mix typically includes a step of adding a liquid ingredient to the mix to prepare dough (specifically, for example, dough or batter), forming the dough into a predetermined shape, and then heating the formed dough (specifically, for example, baking, steaming, deep-frying, or boiling). A method for producing fried foods with batter using the mix typically includes a step of adding a liquid ingredient to the mix to prepare dough (specifically, for example, batter), attaching the dough to the surface of an ingredient, and then putting the ingredient with batter into heated oil to deep-fry. The liquid ingredient to be added to the mix can be water, oil, seasoning liquid, egg liquid, milk, or the like, and can be appropriately selected depending on the type of dough food to be produced. The mixing ratio of the mix to the liquid ingredient is not particularly limited, but is generally about 50 to 300 parts by mass per 100 parts by mass of the mix.

For example, aspects of the present invention are as follows.
＜1＞
A method for producing a modified resistant starch, comprising the steps of adding 5 to 75 parts by mass of water to 100 parts by mass of resistant starch and then heat-treating the resistant starch, the step making the average particle size of the resistant starch after the heat treatment 1.20 to 1.50 times the average particle size of the resistant starch before the heat treatment.
＜2＞
The method according to <1> above, wherein the heat treatment is carried out under conditions in which the product temperature of the resistant starch is maintained at 120 to 220° C. for 5 to 60 minutes.
＜3＞
The production method according to <1> or <2>, wherein the ratio of the dietary fiber content, calculated as a dry mass, of the modified resistant starch to the dietary fiber content, calculated as a dry mass, of the resistant starch before the heat treatment is 0.9 or more.
＜4＞
The method according to any one of <1> to <3>, wherein the resistant starch is a processed starch that has been subjected to at least a phosphate cross-linking treatment.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples.

[Examples 1 to 9, Comparative Examples 1 to 6]
A prescribed amount of water was added to 100 parts by mass of resistant starch and mixed, the mixture was spread evenly on a tray container, and the contents of the tray container were heat-treated using a flat kiln (manufactured by Tokura Shoji Co., Ltd.) to produce a modified resistant starch. The amount of water added and the conditions of the heat treatment (heating temperature, heating time) are shown in Tables 1 and 2 below. As the resistant starch, phosphate cross-linked starch (manufactured by Matsutani Chemical Industry Co., Ltd., product name "Pine Starch RT", dietary fiber content 95% by mass calculated as starch dry matter) was used.

[Test Example]
The modified resistant starch (33.5% by mass), weak flour (33.5% by mass), sugar (30% by mass) and baking powder (3% by mass) were mixed to prepare a hot cake mix. 25 g of whole egg liquid and 75 g of milk were added to 100 g of the hot cake mix as liquid ingredients, and the mixture was hand-mixed with a whipper at a rotation speed of 120 rpm for 1 minute to prepare a batter. The batter was left to stand for 5 minutes in an environment of normal temperature and pressure, and then the entire amount of the batter was poured onto a griddle and baked at 150°C for 3 minutes, after which the batter was turned upside down and baked at 150°C for another 3 minutes to obtain a hot cake.
In addition, a pancake was obtained in the same manner as described above, except that the resistant starch used as the raw material for the modified resistant starch was used as it was instead of the modified resistant starch, and this was used as a control example.
The resulting hot cakes were tasted by 10 expert panelists, who evaluated the texture (less roughness) according to the following criteria. The results are shown in Tables 1 and 2 below as the average scores of the 10 panelists.

<Texture evaluation criteria>
5 points: Much less grainy texture than the control.
4 points: Less grainy texture than the control.
3 points: Has a rough texture similar to that of the control.
2 points: The texture is rougher than the control.
1 point: The texture is significantly rougher than the control.

As shown in Table 1, in each Example, the amount of water added during the heat treatment was 5 to 75 parts by mass per 100 parts by mass of resistant starch, and the average particle size increase ratio was 1.20 to 1.50 times, so the texture of the pancakes was superior to that of Comparative Examples 1 and 2, which did not meet these requirements.

As shown in Table 2, the average particle size increase ratio in each comparative example was less than 1.20 times, which resulted in the pancakes having an inferior texture compared to each example. Since the heating temperature or heating time in the heat treatment in each comparative example in Table 2 is different from that in each example in Table 2, it can be seen that the average particle size increase ratio can be adjusted by appropriately adjusting the heating temperature and heating time in the heat treatment.

The present invention provides a modified resistant starch that improves the rough texture that is a particular problem with foods containing resistant starch, and does not impair the food's inherent smooth, pleasant texture when used in foods to reduce sugar content.

Claims (4)

A method for producing modified resistant starch, comprising the step of adding 5 to 75 parts by mass of water to 100 parts by mass of resistant starch and then heat-treating the resistant starch, in which the average particle size of the resistant starch after the heat treatment is 1.20 to 1.50 times the average particle size of the resistant starch before the heat treatment. The method of claim 1, wherein the heat treatment is carried out under conditions in which the temperature of the resistant starch is maintained at 120 to 220°C for 5 to 60 minutes. The method according to claim 1 or 2, wherein the ratio of the dietary fiber content of the modified resistant starch, calculated on a dry weight basis, to the dietary fiber content of the resistant starch before the heat treatment, calculated on a dry weight basis, is 0.9 or more. The method according to claim 1 or 2, wherein the resistant starch is a processed starch that has been subjected to at least a phosphate cross-linking treatment.