Rice that suppresses the rise in blood sugar levels

Abstract

To provide a rice food product or a rice processed product capable of inhibiting blood glucose level elevation, especially, a method for manufacturing a rice food product or a rice processed product lowering a glycemic index.SOLUTION: There are provided a method for manufacturing a rice food product inhibiting blood glucose level elevation which includes a step of adding (1) α-glucosidase (AG) and blanching enzyme (BE), (2) AG, BE and 4-α-glucanotransferase or (3) exo-type amylase and 4-α-glucanotransferase, to a raw rice material; a method for imparting an effect for inhibiting blood glucose level elevation to a rice food product; an enzyme preparation for imparting an effect for inhibiting blood glucose level elevation to a rice food product; a method for manufacturing a rice food product lowering a glycemic index (GI) which includes a step of adding (1), (2) or (3) to a raw rice material; a method for lowering GI of a rice food product; and an enzyme preparation for lowering GI of a rice food product.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing rice in which the rise in blood glucose levels is suppressed, a method for imparting an effect of suppressing the rise in blood glucose levels to rice, an enzyme preparation for imparting an effect of suppressing the rise in blood glucose levels to rice, a method for producing rice with a reduced glycemic index, a method for reducing the glycemic index of rice, and an enzyme preparation for reducing the glycemic index of rice. [Background technology]

[0002] Elevated blood sugar levels are a cause of obesity and diabetes. Starch-containing foods such as white rice and bread, which are staples of the Japanese diet, tend to raise blood sugar levels after meals and are generally considered to have a high glycemic index (GI). Various methods have been developed to lower blood sugar levels after eating rice. For example, methods of adding brown rice, dietary fiber, and indigestible dextrin to white rice are known, but these have the problem of worsening taste and color. In addition, high-amylose rice has been developed, but in addition to the problem of taste, there are issues with limited production volume and high cost.

[0003] Patent Document 1 discloses a method for producing indigestible carbohydrates, characterized by a step of acting maltotriosyltransferase on carbohydrates. Patent Document 2 discloses a method for producing digestion-delayed carbohydrates that do not change the GI value, characterized by a step of acting blanching enzyme and exo-type amylase on carbohydrates. Non-Patent Document 1 discloses a method for producing indigestible carbohydrates, characterized by a step of acting blanching enzyme and amylomaltase on carbohydrates. Patent Document 3 discloses rice that suppresses blood glucose rise, having an amylose content of 25% or more. Patent Document 4 discloses a manufacturing method that exhibits an anti-aging effect on starch-containing foods, characterized by adding blanching enzyme and α-glucosidase to the raw materials. However, none of the above-mentioned literature reports any findings indicating that enzymatic reactions during the rice cooking process can impart structural changes that affect digestibility. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-214255 [Patent Document 2] International Publication No. 2018 / 123901 [Patent Document 3] Japanese Patent Publication No. 2005-328776 [Patent Document 4] International Publication No. 2014 / 115894 [Non-patent literature]

[0005] [Non-Patent Document 1] Carbohydrate Polymers 132(2015) 409-418 [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of this invention is to provide a method for producing rice-based foods or rice-based products that can suppress the rise in blood glucose levels, particularly rice-based foods or rice-based products with a reduced glycemic index. [Means for solving the problem]

[0007] The inventors of the present invention conducted diligent research to solve the above problems and discovered that by adding a specific enzyme during the cooking of rice and reacting it with the starch in the rice, it is possible to produce rice food products or rice processed products that can suppress the rise in blood glucose levels, particularly rice food products or rice processed products with a reduced glycemic index. Based on this finding, the inventors conducted further diligent research and completed the present invention.

[0008] In other words, the present invention provides the following: [1] A method for producing a rice food product or rice processed product (or a rice food product or rice processed product that is made indigestible) in which the rise in blood glucose levels is suppressed, comprising the step of adding exo-type amylase and 4-α-glucanotransferase to raw rice as a raw material. [2] The method for producing the product according to [1] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase. [3] The manufacturing method according to [1] or [2] above, further comprising a step of adding the exo-type amylase and 4-α-glucanotransferase, followed by a rice cooking step.

[0009] [4] A method for imparting an effect of suppressing blood glucose elevation to rice food products or rice processed products, comprising the step of adding exo-type amylase and 4-α-glucanotransferase to raw rice as a raw material (or a method for imparting indigestibility to rice food products or rice processed products). [5] The method according to [4] above, wherein the 4-α-glucanotransferase is selected from the group consisting of maltotriosyltransferase and amylomaltase. [6] The method according to [4] or [5] above, further comprising the step of adding the exo-type amylase and 4-α-glucanotransferase, followed by a rice cooking step.

[0010] [7] An enzyme preparation containing exo-type amylase and 4-α-glucanotransferase for imparting an effect of suppressing blood glucose elevation to rice foods or rice products (or for imparting indigestibility to rice foods or rice products). [8] The enzyme preparation according to [7] above, wherein 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase. [9] The enzyme preparation described in [7] or [8] above for use in the rice cooking process.

[0011]

[10] A method for producing a cooked rice food or a rice processed product with a reduced glycemic index, which includes a step of adding an exo-type amylase and a 4-α-glucanotransferase to a raw material that is raw rice.

[11] The production method according to

[10] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[12] The production method according to

[10] or

[11] above, which includes a rice-cooking step following the step of adding the exo-type amylase and the 4-α-glucanotransferase.

[0012]

[13] A method for reducing the glycemic index of a cooked rice food or a rice processed product, which includes a step of adding an exo-type amylase and a 4-α-glucanotransferase to a raw material that is raw rice.

[14] The method according to

[13] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[15] The method according to

[13] or

[14] above, which includes a rice-cooking step following the step of adding the exo-type amylase and the 4-α-glucanotransferase.

[0013]

[16] An enzyme preparation for reducing the glycemic index of a cooked rice food or a rice processed product, which contains an exo-type amylase and a 4-α-glucanotransferase.

[17] The enzyme preparation according to

[16] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[18] The enzyme preparation according to

[16] or

[17] above, for use in a rice-cooking step.

[0014]

[19] A method for producing a cooked rice food or a rice processed product (or a cooked rice food or a rice processed product with improved indigestibility) with suppressed blood glucose level increase, which includes a step of adding an enzyme of the following (1) or (2) to a raw material that is raw rice. (1) α-Glucosidase and a branching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[20] The method for producing the product according to

[19] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[21] The manufacturing method according to

[19] or

[20] above, further comprising a rice cooking step following the step of adding the enzyme.

[0015]

[22] A method for imparting an effect of suppressing blood glucose elevation to a rice food product or rice processed product, comprising the step of adding the enzyme (1) or (2) below to a raw rice raw material (or a method for imparting indigestibility to a rice food product or rice processed product). (1) α-glucosidase and blanching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[23] The method according to

[22] above, wherein the 4-α-glucanotransferase is selected from the group consisting of maltotriosyltransferase and amylomaltase.

[24] The method according to

[22] or

[23] above, further comprising a rice cooking step following the step of adding the enzyme.

[0016]

[25] An enzyme preparation containing the enzyme described in (1) or (2) below, for imparting an effect of suppressing blood glucose elevation to rice foods or rice products (or for imparting indigestibility to rice foods or rice products). (1) α-glucosidase and blanching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[26] The enzyme preparation according to

[25] above, wherein 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[27] The enzyme preparation described in

[25] or

[26] above for use in the rice cooking process.

[0017]

[28] A method for producing a rice food product or rice processed product in which the glycemic index has been reduced, comprising the step of adding the enzyme (1) or (2) below to a raw rice raw material. (1) α-glucosidase and blanching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[29] The method for producing the product according to

[28] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[30] The manufacturing method according to

[28] or

[29] above, further comprising a rice cooking step following the step of adding the enzyme.

[0018]

[31] A method for reducing the glycemic index of a rice food product or a rice processed product, comprising the step of adding the enzyme (1) or (2) below to a raw rice raw material. (1) α-glucosidase and blanching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[32] The method according to

[31] above, wherein the 4-α-glucanotransferase is selected from the group consisting of maltotriosyltransferase and amylomaltase.

[33] The method according to

[31] or

[32] above, further comprising a step of adding the enzyme, followed by a step of cooking rice.

[0019]

[34] An enzyme preparation for reducing the glycemic index of rice food products or rice processed products, containing the enzyme described in (1) or (2) below. (1) α-glucosidase and blanching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[35] The enzyme preparation according to

[34] above, wherein 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[36] The enzyme preparation described in

[34] or

[35] above for use in the rice cooking process.

[0020]

[37] A method for suppressing the rise in blood glucose levels in a subject who requires suppression of the rise in blood glucose levels, comprising administering a rice food product or a rice processed product manufactured by a method that includes the step of adding exo-type amylase and 4-α-glucanotransferase to raw rice as a raw material.

[38] The method according to

[37] above, wherein the 4-α-glucanotransferase is selected from the group consisting of maltotriosyltransferase and amylomaltase.

[39] The method according to

[37] or

[38] above, wherein the rice food or rice processed product is produced by a method comprising a step of adding the exo-type amylase and 4-α-glucanotransferase, followed by a step of cooking rice.

[0021]

[40] Rice food or rice processed product manufactured by a method comprising the step of adding exo-type amylase and 4-α-glucanotransferase to raw rice as a raw material for use in suppressing the rise in blood glucose levels.

[41] The rice food or rice processed product according to

[40] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[42] A rice food or rice product according to

[40] or

[41] above, manufactured by a method comprising a step of adding the exo-type amylase and 4-α-glucanotransferase, followed by a rice cooking step.

[0022]

[43] Use of exo-type amylase and 4-α-glucanotransferase for manufacturing rice-based food products or processed rice products that suppress blood glucose elevation using raw rice as a raw material.

[44] Use according to

[43] above, wherein 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[45] The use described in

[43] or

[44] above, wherein the exo-type amylase and 4-α-glucanotransferase are used in the rice cooking process.

[0023]

[46] A method for suppressing the rise in blood glucose levels in a subject who requires suppression of blood glucose levels, comprising administering a rice food product or a rice processed product manufactured by a method that includes the step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-glucosidase and blanching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[47] The method according to

[46] above, wherein the 4-α-glucanotransferase is selected from the group consisting of maltotriosyltransferase and amylomaltase.

[48] ​​The method according to

[46] or

[47] above, wherein the rice food or rice processed product is manufactured by a method that includes a rice cooking step following the step of adding the enzyme.

[0024]

[49] Rice food or rice processed product manufactured by a method comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material for use in suppressing the rise in blood glucose levels. (1) α-glucosidase and blanching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[50] The rice food or rice processed product according to

[49] above, wherein 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[51] A rice food or rice product according to

[49] or

[50] above, manufactured by a method including a rice cooking step following the step of adding the enzyme.

[0025]

[52] Use of the enzymes described in (1) or (2) below for the manufacture of rice-based food products or rice processed products that suppress the rise in blood sugar levels using raw rice as a raw material. (1) α-glucosidase and blanching enzyme (2) α-glucosidase, blanching enzyme and 4-α-glucanotransferase

[53] The use described in

[52] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

[54] The use described in

[52] or

[53] above, wherein the enzyme is used in the rice cooking process. [Effects of the Invention]

[0026] According to the present invention, by adding a specific enzyme during the production of cooked rice and reacting it with the starch in the rice, it is possible to produce cooked rice that can suppress the rise in blood glucose levels after meals compared to cooked rice without enzymes. According to the present invention, by this production method, it is possible to produce cooked rice with a lower glycemic index compared to cooked rice without enzymes. [Brief explanation of the drawing]

[0027] [Figure 1] Figure 1 shows the examination schedule for Examination Example 1. [Figure 2] Figure 2 shows the results of Test Example 2. [Figure 3] Figure 3 shows the results of Test Example 7. [Modes for carrying out the invention]

[0028] The present invention will be described in detail below. The blanching enzyme (enzyme number EC2.4.1.18) used in the present invention is an enzyme that transfers a portion of the 1,4-α-D-glucan chain to the 6-OH group of the receptor 1,4-α-D-glucan, thereby generating a branched structure of α-1,6 linkages, such as amylopectin or glycogen. One example is the food-grade enzyme "Blanching Enzyme" manufactured by Nagase & Co., Ltd. (for example, "Blanching Enzyme A" (product name), Nagase & Co., Ltd.). The enzyme activity of the blanching enzyme was defined as follows: 50 μl of 0.1% amylose B (Nacalai Tesque) dissolved in 0.08 M phosphate buffer (pH 7.0) was added to 50 μl of enzyme solution dissolved in 0.1 M phosphate buffer (pH 7.0). After reacting at 50°C for 30 minutes, 2 ml of iodine reagent (0.5 ml of a solution of 0.26 g I2 and 0.26 g KI dissolved in 10 ml of ultrapure water mixed with 0.5 ml of 1 N HCl and diluted to 130 ml) was added, and the absorbance at 660 nm was measured. In this reaction system, the amount of enzyme that reduces the 660 nm absorbance by 1% per minute of reaction was defined as 1 U (unit).

[0029] In this invention, exo-type amylase refers to an enzyme that sequentially degrades α-1,4 glycosidic bonds from the non-reducing end of starch. In the present invention, examples of exo-type amylases include α-glucosidase and β-amylase. These enzymes can be used in combination of one or more of them.

[0030] The α-glucosidase (EC3.2.1.20) used in this invention is an enzyme that hydrolyzes the non-reducing α-1,4-glucosidic bond to produce α-glucose. Among α-glucosidases, transglucosidase is preferred. The enzymes commercially available from Amano Enzyme Co., Ltd. under the trade names "Transglucosidase 'Amano'" and "α-glucosidase 'Amano'" are examples of α-glucosidase. Regarding the enzymatic activity of α-glucosidase, 1 U (unit) was defined as the amount of enzyme that produced 1 μg of glucose in 2.5 ml of reaction solution when 1 ml of 0.02 M acetate buffer (pH 5.0) was added to 1 mM α-methyl-D-glucoside, 0.5 ml of enzyme solution was added, and the mixture was allowed to react at 40°C for 60 minutes.

[0031] The β-amylase used in the present invention is an exo-type enzyme that has the activity to hydrolyze the α-1,4-glucosidic bonds of starch every other bond (in maltose units) from the non-reducing end. Various types of β-amylases are known, such as those derived from microorganisms and plants. However, the origin of the β-amylase used in the present invention is not particularly limited as long as it has the above-mentioned activity, and any β-amylase of any origin can be used, and recombinant enzymes may also be used. The β-amylase used in the present invention may be a commercially available product. Specific examples include Hymaltosin GL, Hymaltosin GLH (both manufactured by HBI Co., Ltd.), and β-amylase F "Amano" (manufactured by Amano Enzyme Co., Ltd.). In the present invention, the active unit of β-amylase is measured and defined as follows: p-nitrophenyl-β-D-maltotrioside (PNP-β) is treated with β-amylase. The amount of p-nitrophenol (PNP) produced is then measured by absorbance at 400 nm. One unit (U) is defined as the amount of enzyme that dissociates 1 μmol of PNP per minute.

[0032] In the present invention, 4-α-glucanotransferase is an enzyme that transfers a glucosyl group or a unit consisting of two or more glucose molecules from the non-reducing end of a donor molecule to an acceptor molecule. Examples of 4-α-glucanotransferases in the present invention include maltotriosyltransferase and amylomaltase. These enzymes can be used in combination of one or more.

[0033] In the present invention, maltotriosyltransferase (EC2.4.1.25) is an enzyme that acts on polysaccharides and oligosaccharides having α-1,4 glucosidic bonds as a binding mode, and transfers maltotriose units to sugars. The enzyme activity of the maltotriosyltransferase used in this invention can be measured by the 4-α-glucanotransferase activity test, and 1 U (unit) is defined as the amount of enzyme that produces 1 μmol of glucose per minute from maltotetraose when reacted at pH=6.5 and 40°C for 60 minutes. An example of maltotriosyltransferase is the enzyme commercially available from Amano Enzyme Co., Ltd. under the trade names "Glycotransferase" and "Glycotransferase 'Amano' L".

[0034] In this invention, amylomaltase (EC2.4.1.25) refers to an enzyme that catalyzes a chemical reaction in which a portion of an α-glucan chain is transferred from the non-reducing end of one α-glucan (e.g., amylose, amylopectin, starch, etc.) to the non-reducing end of another α-glucan (or glucose). The α-glucan chain donor molecule and the acceptor molecule may be the same, in which case intramolecular transfer occurs and the product has a cyclic structure. In this invention, the active unit of amylomaltase is measured by the method of Srisimatrat et al. (Srisimatrat et al., Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2011, vol.70, p.369) or a similar method. Specifically, it is measured and defined as follows: A reaction solution of 0.05% solubilized starch, 0.05% maltose, 30 mM sodium acetate buffer (pH 5.5), and 0.01 mL of enzyme solution is reacted at 70°C for 5 minutes, and then heated at 96°C for 5 minutes to stop the reaction. Subsequently, 0.1 mL of the reaction solution is mixed with 1 mL of iodine solution (0.02% I2, 0.2% KI), and the absorbance at 600 nm is measured. The activity value is defined as the difference between the measured value with enzyme and the measured value without enzyme (control). One unit (U) of enzyme is defined as the amount that reduces the absorbance at 600 nm by 1 per minute. In the present invention, amylomaltase includes amylomaltase derived from Corynebacterium, etc.

[0035] The present invention relates to a method for producing rice food or rice processed products in which blood glucose levels are suppressed, comprising the step of adding the enzyme (1), (2), or (3) described below to raw rice as a raw material. (1) α-glucosidase and blanching enzyme (which may be referred to as enzyme (1) in this specification). (2) α-glucosidase, blanching enzyme, and 4-α-glucanotransferase (which may be referred to as enzyme (2) in this specification). (3) Exo-type amylase and 4-α-glucanotransferase (which may be referred to as enzyme (3) in this specification).

[0036] In the present invention, the enzyme (2) can be any of the following (2-i) to (2-iii). (2-i)α-glucosidase, blanching enzyme and maltotriosyltransferase (2-ii) α-glucosidase, blanching enzyme and amylomaltase (2-iii) α-glucosidase, blanching enzyme, maltotriosyltransferase and amylomaltase

[0037] In the present invention, enzyme (3) can be any of the following (3-i) to (3-ix). (3-i)α-glucosidase and maltotriosyltransferase (3-ii) α-glucosidase and amylomaltase (3-iii) α-glucosidase, maltotriosyltransferase and amylomaltase (3-iv)β-amylase and maltotriosyltransferase (3-v)β-amylase and amylomaltase (3-vi)β-amylase, maltotriosyltransferase, and amylomaltase (3-vii)α-glucosidase, β-amylase, and maltotriosyltransferase (3-viii) α-glucosidase, β-amylase, and amylomaltase (3-ix) α-glucosidase, β-amylase, maltotriosyltransferase, and amylomaltase

[0038] The raw material used in this invention is raw rice. The type of rice and whether or not it has been polished are not particularly limited, and examples include polished rice, brown rice, germinated brown rice, high-amylose rice, low-amylose rice, etc. In the present invention, rice-based foods include, for example, cooked rice (white rice, brown rice, sprouted brown rice, high-amylose rice, low-amylose rice, rice with barley, rice with glutinous barley, rice with mixed grains, rice with indigestible carbohydrates), vinegared rice (sushi rice), red bean rice, pilaf, fried rice, mixed rice dishes, sticky rice, porridge, risotto, rice balls, sushi, and bento boxes. In the present invention, processed rice products include, for example, rice crackers, Japanese sweets, and mochi. Frozen, aseptically packaged, retort-packaged, dried, and canned versions of these products are also included. In this specification, "food" is a broad concept encompassing anything that can be taken orally (excluding pharmaceuticals), and includes not only so-called "foods" but also beverages, health supplements, functional foods (e.g., foods for specified health uses, foods with functional claims, foods with nutritional function claims), supplements, etc.

[0039] In the method for producing cooked rice (cooked rice food or processed rice product) of the present invention, enzymes are added to the raw rice before cooking and reacted with the starch in the rice during the cooking process. The enzymes may be added to the raw rice at any stage before cooking. These enzymes may be added to the soaking solution in which the raw rice is soaked for water absorption, but it is preferable to add the enzymes after soaking and before cooking. In addition, although multiple enzymes are used in combination in the present invention, the order in which these enzymes are added to the rice is not particularly important; one type may be added first, followed by the remaining enzymes, but it is preferable to add multiple enzymes simultaneously. Furthermore, ingredients commonly used in food products may also be used in combination.

[0040] Enzymes (1): α-glucosidase and blanching enzymes In the present invention, when enzyme (1) is used, the amount of α-glucosidase added is preferably 0.0005 to 100 U, more preferably 0.001 to 30 U, even more preferably 0.005 to 10 U, and particularly preferably 0.01 to 3 U per 1 g of raw rice. In the present invention, when enzyme (1) is used, the amount of blanching enzyme added is preferably 0.001 to 3000 U, more preferably 0.05 to 2000 U, even more preferably 0.1 to 1000 U, and particularly preferably 1 to 600 U, in terms of enzyme activity per 1 g of raw rice. Furthermore, the ratio of α-glucosidase to blanching enzyme (α-glucosidase:blanching enzyme) is preferably 1U:1×10 -3 ~6×10 7 U, Comfort 1U: 1 x 10 -2 ~6×10 6 U, more preferably 1U:1×10 -1 ~6×10 5 U, particularly preferably 1U: 1~6 × 10 4 It is U.

[0041] Enzymes (2): α-glucosidase, blanching enzymes, and 4-α-glucanotransferase In the present invention, when enzyme (2) is used, the amount of α-glucosidase added is preferably 0.0005 to 100 U, more preferably 0.001 to 30 U, even more preferably 0.005 to 10 U, and particularly preferably 0.01 to 3 U per 1 g of raw rice. In the present invention, when enzyme (2) is used, the amount of blanching enzyme added is preferably 0.001 to 3000 U, more preferably 0.05 to 2000 U, even more preferably 0.1 to 1000 U, and particularly preferably 1 to 600 U, in terms of enzyme activity per 1 g of raw rice. In the present invention, when using enzyme (2), the addition amount of 4-α-glucanotransferase (for example, maltotriosyltransferase, amylomaltase) is such that the enzyme activity is preferably 0.00005 to 100 U, more preferably 0.0001 to 30 U, still more preferably 0.005 to 10 U, and particularly preferably 0.01 to 4 U per 1 g of raw polished rice. Also, the ratio of the addition amounts of α-glucosidase, branching enzyme, and 4-α-glucanotransferase (for example, maltotriosyltransferase, amylomaltase) (α-glucosidase:branching enzyme:4-α-glucanotransferase) is preferably 1 U:1×10 -3 ~6×10 7 U:1×10 -5 ~4×10 5 U, more preferably 1 U:1×10 -2 ~6×10 6 U:1×10 -4 ~4×10 4 U, still more preferably 1 U:1×10 -1 ~6×10 5 U:1×10 -3 ~4×10 3 U, particularly preferably 1 U:1~6×10 4 U:1×10 -2 ~4×10 2 U. In enzyme (2), only one type of 4-α-glucanotransferase may be used, or a combination of multiple types of 4-α-glucanotransferases may be used. In enzyme (2), when using a combination of multiple types of 4-α-glucanotransferases, the addition amount is such that the "addition amount of each enzyme" of the multiple types of 4-α-glucanotransferases is within the above-described range.

[0042] Enzyme (3): Exo-type amylase and 4-α-glucanotransferase In the present invention, when enzyme (3) is used, the amount of exo-type amylase (e.g., α-glucosidase, β-amylase) added is preferably 0.0005 to 100 U, more preferably 0.001 to 30 U, even more preferably 0.005 to 10 U, and particularly preferably 0.01 to 3 U per 1 g of raw rice. In the present invention, when enzyme (3) is used, the amount of 4-α-glucanotransferase (e.g., maltotriosyltransferase, amylomaltase) added is preferably 0.001 to 100 U, more preferably 0.1 to 30 U, even more preferably 1 to 20 U, and particularly preferably 3 to 10 U per 1 g of raw rice. Furthermore, the ratio of exo-type amylase (e.g., α-glucosidase, β-amylase) to 4-α-glucanotransferase (e.g., maltotriosyltransferase, amylomaltase) added (exo-type amylase:4-α-glucanotransferase) is preferably 1U:0.005~500U, more preferably 1U:0.5~150U, even more preferably 1U:5~100U, and particularly preferably 1U:15~50U. In enzyme (3), exo-type amylase and 4-α-glucanotransferase may be used individually or in combination of multiple types. In enzyme (3), when using multiple types of exo-type amylase in combination, the amount to be added should be such that the "amount to be added for each enzyme" of the multiple types of exo-type amylase is within the range described above. Similarly, when using multiple types of 4-α-glucanotransferase in combination, the amount to be added should be such that the "amount to be added for each enzyme" of the multiple types of 4-α-glucanotransferase is within the range described above.

[0043] The reaction time for each enzyme is not particularly limited as long as it allows the enzyme to act on the starch in the rice substrate, but a practical reaction time of 5 minutes to 24 hours is preferable. Similarly, the reaction temperature is not particularly limited as long as it is within the range in which the enzyme maintains its activity, but a practical temperature of 0 to 100°C is preferable. In other words, by using these enzymes in a normal rice cooking process, sufficient reaction time and temperature can be obtained to achieve the effects of the present invention. In the present invention, the rice cooking process preferably includes a step of raising the temperature from room temperature to 100°C over a period of 5 to 60 minutes, more preferably 10 to 50 minutes, even more preferably 10 to 30 minutes, and even more preferably about 10 minutes, taking into account the enzyme reaction time. When 100°C is reached, the enzyme is deactivated and the enzymatic reaction is completed. After that, a boiling process (for example, 15 to 30 minutes, preferably about 15 to 20 minutes) and a steaming process (for example, 10 to 40 minutes, preferably about 10 to 20 minutes) are usually performed to produce the rice with suppressed blood glucose rise (rice with a reduced glycemic index) according to the present invention. In the present invention, the rice cooking process is, for example, 3 hours or less, preferably 2 hours or less, and more preferably about 1 hour (about 50 to 60 minutes) after the enzyme is added. The present invention is advantageous over the prior art in that the effect can be obtained even if the rice cooking process is completed in a short time (for example, about 1 hour) after the enzyme is added. In this invention, the rice cooking process may be carried out using a commercially available rice cooker.

[0044] The manufacturing method of the present invention may include steps other than those described above (for example, a drying step, a freeze-drying step), as long as they do not impair the effects of the present invention.

[0045] The manufacturing method of the present invention described above makes it possible to produce rice in which the rise in blood glucose levels is suppressed (rice with a reduced glycemic index). In the present invention, the effect of suppressing the rise in blood glucose levels can be evaluated by measuring blood glucose levels over time 2 hours after administration (after ingestion) using the methods described in Test Example 1 and Test Example 7 below, or a similar method, calculating the Δblood glucose AUC value, and comparing it with the Δblood glucose AUC value of the control (enzyme-free). The cooked rice produced by the manufacturing method of the present invention has a Δblood glucose AUC value of less than 100, preferably 95 or less, more preferably 90 or less, and more preferably 85 or less, when the Δblood glucose AUC of the control (without enzymes) is set to 100.

[0046] Rice food products or processed rice products manufactured by the manufacturing method of the present invention described above have the effect of suppressing the rise in blood glucose levels in the subject (e.g., human) that ingests (administers) them, compared to when rice food products or processed rice products without added enzymes are ingested (administered). In one aspect, the present invention also relates to: "a method for suppressing the rise in blood glucose levels in a subject who requires suppression of blood glucose levels, comprising administering a rice food product or rice processed product manufactured by a method including the step of adding enzyme (1), enzyme (2), or enzyme (3) to a raw rice raw material to the subject"; "a rice food product or rice processed product manufactured by a method including the step of adding enzyme (1), enzyme (2), or enzyme (3) to a raw rice raw material for use in suppressing the rise in blood glucose levels"; and "the use of enzyme (1), enzyme (2), or enzyme (3) for manufacturing a rice food product or rice processed product for suppressing the rise in blood glucose levels using raw rice as a raw material."

[0047] The present invention relates to a method for imparting an effect of suppressing blood glucose elevation to rice-based foods or rice-based products, comprising the step of adding enzyme (1), enzyme (2), or enzyme (3) to raw rice as a raw material. In the method for providing the effect of suppressing the rise in blood glucose levels according to the present invention, the amount, ratio, and method of adding enzyme (1), enzyme (2), and enzyme (3) are the same as those described in the method for producing rice food or rice processed products according to the present invention.

[0048] The present invention relates to an enzyme preparation containing enzyme (1), enzyme (2), or enzyme (3) for imparting the effect of suppressing blood glucose elevation to rice-based foods or rice processed products. In the enzyme preparation of the present invention, the enzyme content ratio is the same as the ratio of enzyme addition amounts described in the method for producing rice food or rice processed products of the present invention. The enzyme preparation of the present invention can be added to raw rice and reacted with it in accordance with the method described above in the method for producing rice food or rice processed products of the present invention, thereby imparting an effect of suppressing the rise in blood glucose levels to rice food or rice processed products.

[0049] In addition to enzymes (1), (2), and (3), the enzyme preparation of the present invention may also contain excipients such as dextrin, starch, modified starch, indigestible dextrin, and reduced maltose; seasonings such as meat extract; proteins such as vegetable protein, gluten, egg white, gelatin, and casein; protein hydrolysates, partially hydrolyzed proteins, emulsifiers, chelating agents such as citrates and polyphosphates; reducing agents such as glutathione and cysteine; alginic acid, lye water, oils and fats, pigments, acidulants, flavorings, and other food additives. The enzyme preparation of the present invention may be in any form: liquid, paste, granules, or powder.

[0050] The present invention also relates to a method for producing a rice food product or rice processed product with a reduced glycemic index, comprising the step of adding enzyme (1), enzyme (2), or enzyme (3) to a raw rice raw material; and a method for reducing the glycemic index of a rice food product or rice processed product, comprising the step of adding enzyme (1), enzyme (2), or enzyme (3) to a raw rice raw material. In the present invention, a method for producing rice food products or processed rice products with a reduced glycemic index; a method for reducing the glycemic index of rice food products or processed rice products; the amount, ratio, and method of adding enzyme (1), enzyme (2), and enzyme (3) are the same as those described in the above-mentioned method for producing rice food products or processed rice products of the present invention.

[0051] The present invention also relates to an enzyme preparation containing enzyme (1), enzyme (2), or enzyme (3) for reducing the glycemic index of rice food products or rice processed products. In the enzyme preparation for reducing the glycemic index of rice food products or rice processed products of the present invention, the enzyme content ratio is the same as the ratio of enzyme addition amounts described in the method for producing rice food products or rice processed products of the present invention. The enzyme preparation of the present invention can be added to raw rice and reacted with it in accordance with the method described above in the method for producing rice food or rice processed products of the present invention, thereby lowering the glycemic index of the rice food or rice processed product. The enzyme preparation of the present invention may further contain the above-mentioned food additives, etc., in addition to enzyme (1), enzyme (2), and enzyme (3). The enzyme preparation of the present invention may be in any form: liquid, paste, granules, or powder.

[0052] In the present invention, the calculation of the glycemic index (GI value) and the preparation of a standard diet can be carried out according to the following. [How to calculate the GI value] First reference meal intake: Participants will consume rice equivalent to 50g of carbohydrates, and blood glucose levels will be measured by finger prick blood sampling on an empty stomach, and 15, 30, 45, 60, 90, and 120 minutes after intake. Second standard meal intake: Consume rice equivalent to 50g of carbohydrates, and measure blood glucose levels as in the first intake. Setting of reference values: The area under the blood glucose curve (IAUC) for two standard meals is calculated, and subjects with a difference of 25% or less in the area under the curve are selected. The average of the IAUCs is then used as the reference value. Ingestion of test food: Blood glucose levels will be measured by finger prick blood sampling on an empty stomach, and 15, 30, 45, 60, 90, and 120 minutes after ingestion. Calculation of GI value: The area under the blood glucose curve (IAUC) of the test food is calculated, and the percentage of the normal range is defined as the GI value. Other regulations will be implemented in accordance with the protocol established by the Japan Glycemic Index Research Association. (http: / / www.gikenkyukai.com / protocol.html) [Preparation of standard diet] The standard meal consists of cooked white rice (non-glutinous rice) prepared with a water content of 135%, providing an amount of rice equivalent to 50g of carbohydrates per person.

[0053] In this specification, "decrease" in the glycemic index means that the glycemic index value is lower than that of rice food products or rice processed products manufactured without the addition of enzymes. Cooked rice produced by the manufacturing method of the present invention (for example, cooked white rice, cooked mixed rice of white rice and brown rice) has a glycemic index value of less than 100, preferably 95 or less, more preferably 90 or less, even more preferably 87 or less, 86 or less, 85 or less, 84 or less, 83 or less, 82 or less, 81 or less, 80 or less, 79 or less, 78 or less, 77 or less, 76 or less, 75 or less, 74 or less, 73 or less, 72 or less, or 71 or less, when the glycemic index value of the control (enzyme-free) is set to 100. [Examples]

[0054] The present invention will be described in more detail below based on examples, comparative examples, and test examples, but the present invention is not limited to these.

[0055] [Examples 1-3, Comparative Examples 1-2] The raw material used was Hitomebore rice (raw rice) from Miyagi Prefecture. The brown rice was sourced from a single producer, harvested on the same day, milled on the same day, and then stored in a light-blocking vacuum pack with an oxygen absorber at 5°C until the test. The polished rice was brought to room temperature 30 minutes before weighing on the day of cooking. The polished rice was weighed using an electronic balance (US6002S, Mettler-Toledo Co., Ltd.). The polished rice, placed in a colander, was gently stirred 10 times clockwise in a bowl of tap water. The tap water was changed and the same process was repeated 5 times. After washing the rice, it was soaked in tap water for one hour. The rice was removed from the colander and transferred to a rice cooker pot. Tap water was added to achieve a 150% hydration rate on the electronic balance, the pot was placed in a mini rice cooker (Koizumi Co., Ltd.: KSC-1511 / W), and the amount of enzymes shown in Tables 1-1 and 1-2 was added before cooking to obtain the cooked rice of Examples 1-3. The cooked rice of Comparative Example 1 (Comparative Example 1-1, Comparative Example 1-2) was obtained using the same method as Example 1, except that enzymes were not added. Cooked rice for Comparative Example 2 (Comparative Example 2-1, Comparative Example 2-2) was obtained using the same method as in Comparative Example 1, except that the raw material, Hitomebore rice from Miyagi Prefecture, was changed to Hoshiyutaka (high-amylose rice). The cooked rice from Examples 1-3 and Comparative Examples 1 and 2 was removed immediately after cooking by inverting the rice cooker pot onto a tray. The rice near the pot walls was removed and set aside at the edge of the tray. The rice was leveled, a small gap was left, and it was covered with plastic wrap and allowed to cool at room temperature for 15 minutes. The cooked rice was frozen in a deep freezer at -80°C. The following day, it was freeze-dried using a freeze-dryer (FDU-2100: Tokyo Rikakiki Co., Ltd.) to obtain the cooked rice (freeze-dried products) from Examples 1-3 and Comparative Examples 1 and 2. Preparations 1 and 2 shown in Tables 1-1 and 1-2 were prepared using the same method, differing only in the preparation date. The enzymes in Tables 1-1 and 1-2 are as shown in Table 2.

[0056] [Table 1-1]

[0057] [Table 1-2]

[0058] [Table 2]

[0059] [Test Example 1] Animal study (in vivo): Effect of enzyme-treated rice on suppressing blood glucose elevation. The following method was used to measure blood glucose levels in rats after administering rice, and the effect of suppressing the rise in blood glucose levels was evaluated. The test substances were freeze-dried cooked rice (freeze-dried) from Examples 1-3 and Comparative Examples 1 and 2. The mixture was ground using a mixer mill (MM301: Verder Scientific), dispensed into standing pouches, sealed, stored at room temperature, and used for animal testing. Furthermore, Experiment 1 (Comparative Example 1-1, Comparative Example 2-1, Example 1) shown in Table 3-1 below and Experiment 2 (Comparative Example 1-2, Comparative Example 2-2, Example 2, Example 3) shown in Table 3-2 below were all conducted under the same conditions except for differences in the date and testing facility.

[0060] The total sugar content analysis of enzyme-treated rice was commissioned to the Japan Food Research Laboratories and measured using the phenol-sulfuric acid method. The test substance was prepared as a solution in distilled water on the day of the blood glucose measurement test. Blood glucose levels were measured at fasting, 15 minutes, 30 minutes, 60 minutes, and 120 minutes after administration, according to the blood glucose measurement method described below and the test schedule in Figure 1. The test substance was administered orally at a total glucose content of 2 g / 20 mL / kg.

[0061] (Method for measuring blood glucose levels) Although various glucose tolerance tests have been conducted on rats, this test was carried out by modifying the method described in Japanese Patent Publication No. 2005-328776 (Patent Document 3). [animal] Animal species and strain: rat, Slc: Wistar (SPF) Producer: Nippon SLC Co., Ltd. Gender: Male Age at arrival: 6 weeks old Quarantine and habituation: Animals are habituated from arrival until they are sorted into groups. However, quarantine is conducted for a period of 7 days, counting the arrival day as day 0. General condition observations are performed daily. [Living environment] Temperature: 22±3℃ Humidity: 50±20% Lighting time: 12 hours / day [feed] Type: Lab MR Stock Solid Feed (Nippon Nosan Kogyo Co., Ltd.) or CRF-1 (Oriental Yeast Co., Ltd.) Feeding method: Feed freely except during fasting periods. [Drinking water] Type: Tap water Watering method: Water will be provided freely throughout the trial period. [Selection and grouping of animals] Animals used in the study will be selected from those that showed no abnormalities in general condition during the quarantine and acclimatization period. The animals will be used at 7 weeks of age. On the last day of quarantine and acclimatization, their body weight will be measured, and the animals will be assigned to groups of 6-10 using stratified continuous randomization, with the obtained body weight as the index. [Fasting treatment] Start fasting overnight the evening before the glucose tolerance test. [Measuring blood glucose levels] The vein at the tip of the tail is incised using a scalpel under unanesthetized conditions. Blood leaking from the incision is used for testing (blood glucose level). The blood glucose level is measured using a self-testing glucose meter such as "Accu-Chek" or "Glutest Neo," and the displayed blood glucose level is recorded. This is considered the fasting blood glucose level. The same glucose meter was used for tests conducted on the same day.

[0062] The evaluation criteria were calculated as follows: Fasting blood glucose level was defined as the blood glucose level at 0 minutes. The value obtained by subtracting the blood glucose value at time 0 from the blood glucose value at each measurement time was defined as "Δ blood glucose value (mg / dL)". The highest value among the Δ blood glucose levels at each measurement time is defined as "ΔC" for each individual. max (mg / dL) The value obtained by calculating the area under the Δblood glucose elevation curve was defined as "Δblood glucose AUC (mg / dL·min)". The calculation method followed the method of the Japan Glycemic Index Research Society. The effect of suppressing blood glucose elevation was evaluated by measuring the Δblood glucose AUC of the test substance administration group compared to the Δblood glucose AUC of the control group, which was set to 100. The test results are shown in Tables 3-1 and 3-2.

[0063] [Table 3-1]

[0064] [Table 3-2]

[0065] Comparative Example 1 (Comparative Example 1-1, Comparative Example 1-2) is cooked rice without added enzymes, and is generally a food with a high glycemic index (GI). Comparative Example 2 (Comparative Example 2-1, Comparative Example 2-2) is cooked rice made from high-amylose rice, which is described as having a low GI in Japanese Patent Publication No. 2005-328776 (Patent Document 3). Compared to Comparative Example 1 (Comparative Example 1-1, Comparative Example 1-2), Comparative Example 2 (Comparative Example 2-1, Comparative Example 2-2) showed a lower Δblood glucose AUC, confirming suppression of blood glucose elevation. Examples 1-3 showed lower Δblood glucose AUC compared to Comparative Example 1 (Comparative Example 1-1, Comparative Example 1-2), confirming the suppression of blood glucose elevation. Furthermore, Examples 2 and 3 showed lower Δblood glucose AUC compared to Comparative Example 2 (Comparative Example 2-2), confirming a higher blood glucose elevation suppression effect than existing technologies.

[0066] The above test results suggest that adding the specific enzyme combination of the present invention imparts indigestibility to cooked rice, and that this can be expected to have an effect in suppressing the rise in blood glucose levels from cooked rice.

[0067] [Examples 4 and 5] I weighed out the required amount of polished Hitomebore rice from Miyagi Prefecture, placed it in a colander, and then gently stirred it 20 times clockwise in a bowl of tap water. I changed the tap water and repeated the same process 5 times. After washing the rice, the polished rice was transferred to a rice cooker pot, and tap water was added until the weight reached 235% of the weight of the raw rice (water content: 135% of the weight of the raw rice), and it was soaked for one hour. The pot was placed in a household rice cooker (Mitsubishi IH rice cooker NJ-HS06), the amount of enzyme shown in Table 4 was added, and after lightly stirring to ensure the enzyme was evenly distributed, the rice was cooked using the cooking mode ("white rice" and "mixed rice / normal") to prepare the enzyme-treated rice of Examples 4 and 5. The enzymes in Table 4 are as shown in Table 5.

[0068] [Example 6 and Comparative Example 3] The enzyme-treated rice of Example 6 was prepared using the same method as in Examples 4 and 5, except that the polished rice (Hitomebore variety from Miyagi Prefecture) was changed to a mixture of 75% polished rice (Hitomebore variety from Miyagi Prefecture) and 25% brown rice (Hitomebore brown rice from Miyagi Prefecture). Comparative Example 3, which is enzyme-free cooked rice, was prepared using the same method as in Example 6, except that no enzyme was added.

[0069] [Table 4]

[0070] [Table 5]

[0071] In the following examples 2 and 3, the calculation of the glycemic index (GI value) and the preparation of the standard diet were carried out according to the following procedure. [How to calculate the GI value] First reference meal intake: Participants consumed rice equivalent to 50g of carbohydrates, and blood glucose levels were measured by finger prick blood sampling at fasting time and 15, 30, 45, 60, 90, and 120 minutes after intake. Second standard meal intake: Rice equivalent to 50g of carbohydrates was consumed, and blood glucose levels were measured as in the first instance. Setting of reference values: The area under the blood glucose curve (IAUC) for two standard meals was calculated, and subjects were selected whose area difference was within 25%. The average of the area under the blood glucose curve (IAUC) was then used as the reference value. Ingestion of test food: Blood glucose levels were measured by finger prick blood sampling on an empty stomach, and 15, 30, 45, 60, 90, and 120 minutes after ingestion. Calculation of GI value: The area under the blood glucose curve (IAUC) of the test food was calculated, and the percentage of the normal range was defined as the GI value. Other regulations were implemented in accordance with the protocol established by the Japan Glycemic Index Research Association. (http: / / www.gikenkyukai.com / protocol.html) [Preparation of standard diet] The standard meal consisted of cooked rice made from Miyagi Prefecture-grown "Hitomebore" white rice (non-glutinous rice) prepared with a water content of 135%, with each person receiving a portion of rice equivalent to 50g of carbohydrates.

[0072] [Test Example 2] Measurement of GI value of enzyme-treated rice (white rice) The glycemic index (GI) was measured using enzyme-treated rice from Examples 4 and 5 in 10 healthy adult males (average age 33.9 ± 6.9 years) whose difference in area under the curve (IAUC) between two intake periods was within 25% when consuming a standard diet. A crossover study was conducted, with at least 24 hours between each period of enzyme-treated rice intake from Example 4 and Example 5, and only the enzyme-treated rice consumed was crossed over and repeated. Each participant was provided with an amount of enzyme-treated rice equivalent to 50g of carbohydrates. As a result, the GI value of the enzyme-treated rice consumption group in Example 4 was 90±29 (mean ± standard deviation), and the GI value of the enzyme-treated rice consumption group in Example 5 was 87±33 (mean ± standard deviation). Furthermore, when stratified analysis was performed on subjects with less variability in the intake of the standard diet (the top half of subjects with the smallest percentage variation in peak blood glucose levels (Cmax) between the first and second intakes of the standard diet: N=5, mean age 34.2±5.3 years), the GI value for the enzyme-treated rice intake group in Example 4 was 79±38 (mean ± standard deviation), and the GI value for the enzyme-treated rice intake group in Example 5 was 71±31 (mean ± standard deviation) (Figure 2).

[0073] [Test Example 3] Measurement of the glycemic index (GI) of enzyme-treated mixed rice (75% white rice, 25% brown rice) Ten healthy adult males (average age 29.9 ± 19.4 years) whose difference in area under the curve (IAUC) between two intake periods was within 25% under a standard diet were included in the study. The glycemic index (GI) was measured for the enzyme-free rice intake group (Comparative Example 3) and the enzyme-treated rice intake group (Example 6). A crossover study was conducted, with at least 24 hours between each period for the enzyme-free rice intake group (Comparative Example 3) and the enzyme-treated rice intake group (Example 6), and only the rice intake was crossed over. In both cases, each participant was provided with rice equivalent to 50g of carbohydrates. As a result, the GI value of the group consuming enzyme-free rice in Comparative Example 3 was 81±20 (mean ± standard deviation), and the GI value of the group consuming enzyme-treated rice in Example 6 was 70±18 (mean ± standard deviation).

[0074] In Test Examples 2 and 3, a decrease in the glycemic index (GI) was observed in white rice to which the enzyme composition of the present invention was added, and in a mixture of brown rice and white rice (25% brown rice: 75% white rice) to which the enzyme composition of the present invention was added. This suggests that the enzyme composition of the present invention (enzyme preparation) has an effect of lowering the GI of rice-based foods or rice processed products.

[0075] [Test Example 4] Artificial Digestion Test Using the method described below, starch hydrolysate (dextrin) (substrate) was treated with the enzymes shown in Table 6, and the resulting carbohydrates were subjected to artificial digestion tests to examine whether or not resistance to digestion was imparted to the substrate. (1) Preparation of carbohydrates by enzymes The enzyme in the amounts shown in Table 6 below was added to starch hydrolysate (Pinex #100 (manufactured by Matsutani Chemical Industry Co., Ltd.), final concentration 4% (w / v)) 50 mmol / L phosphate buffer (pH 6.0). After reacting at 50°C overnight (17 hours), the reaction was stopped by boiling in a boiling water bath for 15 minutes to obtain the reaction solutions of Examples 7-12 and Comparative Examples 5-11. In addition, the solution of Comparative Example 4 (control) was obtained by the same method as in Example 7, etc., except that the enzyme was not added. The reaction solutions of Examples 7-12, Comparative Examples 5-11, and Comparative Example 4 were cooled and used as samples for the artificial digestion test described in (2) below. In addition, the amount of free glucose in the reaction solutions obtained from Examples 7-12, Comparative Examples 5-11, and Comparative Example 4 was determined separately by the glucose oxidase method (Fujifilm Wako Pure Chemical Industries: Lab Assay™ Glucose). The amount of free glucose obtained at this time will be referred to as "amount of free glucose after enzymatic reaction." The substrate (carbohydrate) after the enzymatic reaction, excluding free glucose, is referred to as "enzyme-modified dextrin." The amount obtained by subtracting the "amount of free glucose after the enzymatic reaction" from the amount of substrate before the enzymatic reaction is referred to as the "amount of enzyme-modified dextrin." The amount of free glucose after the enzyme reaction per 1 mL of reaction solution (amount of free glucose after the enzyme reaction (mg / mL)) and the amount of enzyme-modified dextrin per 1 mL of reaction solution (amount of enzyme-modified dextrin (mg / mL)) were calculated and used to calculate the degradation rate of enzyme-modified dextrin below. The enzymes listed in Table 6 are shown in Table 7.

[0076] (2) Method for artificial digestion testing and method for calculating the degradation rate of enzyme-modified dextrin The artificial digestion test was performed using the following method, based on an improved version of the "Quantitative Method for Indigestible Components" (Starch Science, Vol. 37, No. 2, p. 107, 1990). First, 0.5 mL of the sample (the reaction solutions from Examples 7-12, Comparative Examples 5-11, and Comparative Example 4 obtained in (1)) was mixed with 10 μL of 10% α-amylase (Novozymes: Termamyl) and reacted at 95°C for 30 minutes. After cooling, 10 μL of 0.1% amyloglucosidase (Sigma) was added and reacted at 60°C for 30 minutes. The reaction was stopped by boiling in a boiling water bath for 15 minutes to obtain the digestion test reaction solution. The amount of free glucose in the obtained digestion test reaction solution was determined by the glucose oxidase method (Fujifilm Wako Pure Chemical Industries: Lab Assay™ Glucose). This amount of free glucose is referred to as "amount of free glucose after artificial digestion test." The amount of free glucose after artificial digestion per 1 mL of the reaction solutions obtained in Examples 7-12 and Comparative Examples 5-11, and the amount of free glucose after artificial digestion per 1 mL of the solution of Comparative Example 4 (amount of free glucose after artificial digestion (mg / mL)) were calculated and used to calculate the degradation rate of enzyme-modified dextrin below.

[0077] The degradation rate of enzyme-modified dextrin in the reaction solutions of Examples 7-12, Comparative Examples 5-11, and Comparative Example 4 obtained in (1) was calculated using the following formula. The results are shown in Table 6. (calculation formula) Degradation rate of enzyme-modified dextrin (weight %) = {Amount of free glucose after artificial digestion test (mg / mL) - Amount of free glucose after enzymatic reaction (mg / mL)} / Amount of enzyme-modified dextrin (mg / mL)

[0078] [Table 6]

[0079] As shown in Table 6, compared to Comparative Example 4 (no enzyme added), Comparative Example 5 (AG used alone), and Comparative Examples 6-11 (MTT used alone), it was confirmed that the degradation rate of enzyme-modified dextrin was lower in Examples 7-12, which used AG and MTT in combination. These results suggest that the combined use of exo-amylase (AG) and 4-α-glucanotransferase (MTT) is effective in producing foods that can suppress the rise in blood glucose levels (foods with added resistance to digestion) compared to foods without added enzymes or foods using enzymes alone.

[0080] [Table 7]

[0081] [Test Example 5] Artificial Digestion Test Using the same method as in Test Example 4, artificial digestion tests were conducted on carbohydrates obtained by treating starch hydrolysate (dextrin) (substrate) with the enzymes shown in Table 8 to examine whether or not resistance to digestion was imparted to the substrate. The enzymes listed in Table 8 are as shown in Table 7 above.

[0082] [Table 8]

[0083] As shown in Table 8, compared to Comparative Example 12 (no enzyme added), Comparative Example 13 (AG alone used), Comparative Examples 14-16 (AA alone used), Comparative Examples 17-19 (AA and MTT used in combination), Comparative Examples 20-22 (MTH alone used), and Comparative Examples 23-25 ​​(MTH and MTT used in combination), it was confirmed that Example 13, which used AG (exo-amylase) and MTT in combination, had a lower degradation rate of enzyme-modified dextrin. These results suggest that exo-amylase (AG), among amylases, is effective in producing foods that can suppress blood glucose elevation (foods with added indigestibility) when used in combination with 4-α-glucanotransferase (MTT).

[0084] [Test Example 6] Artificial Digestion Test Except for changing the step in Test Example 4, "reacting overnight (17 hours) at 50°C followed by boiling in a boiling water bath for 15 minutes to stop the reaction," to "reacting at 50°C for 4 hours followed by boiling in a boiling water bath for 15 minutes," the same method as in Test Example 4 was used to treat starch hydrolysate (dextrin) (substrate) with the enzymes shown in Table 9. An artificial digestion test was then performed on the carbohydrates obtained to examine whether or not resistance to digestion was imparted to the substrate. The enzymes listed in Table 9 are as shown in Table 7 above.

[0085] [Table 9]

[0086] As shown in Table 9, compared to Comparative Example 26 (no enzyme added), Comparative Examples 27 and 28 (AG alone used), and Comparative Example 29 (MTT alone used), it was confirmed that the degradation rate of enzyme-modified dextrin was lower in Examples 14 and 15, which used AG and MTT in combination. Furthermore, compared to Comparative Example 26 (no enzyme added), Comparative Examples 30-32 (using BA alone), and Comparative Example 29 (using MTT alone), it was confirmed that the degradation rate of enzyme-modified dextrin was lower in Examples 16-18, which used BA and MTT in combination. These results suggest that the combined use of exo-type amylase (AG, BA) and 4-α-glucanotransferase (MTT) is effective in producing foods that can suppress the rise in blood glucose levels (foods with added resistance to digestion) compared to foods without added enzymes or foods using enzymes alone.

[0087] [Example 19, Comparative Examples 33 and 34] The raw material used was Hitomebore rice (raw rice) from Miyagi Prefecture. The brown rice was sourced from a single producer, harvested on the same day, milled on the same day, and then stored in a light-blocking vacuum pack with an oxygen absorber at 5°C until the test. The polished rice was brought to room temperature 30 minutes before weighing on the day of cooking. The polished rice was weighed using an electronic balance (US6002S, Mettler Toledo Co., Ltd.). The polished rice, placed in a colander, was gently stirred 10 times clockwise in a bowl of tap water. The tap water was changed and the same process was repeated 5 times. After washing the rice, it was soaked in tap water for one hour. The rice was removed from the colander and transferred to a rice cooker pot. Tap water was added to achieve a 135% hydration rate on the electronic balance, the pot was placed in a household rice cooker (Mitsubishi: NJ-LH064), and the amount of enzyme shown in Table 10 was added before cooking to obtain the cooked rice of Example 19 and Comparative Example 34. The cooked rice of Comparative Example 33 was obtained using the same method as Example 19, except that enzyme was not added. The cooked rice from Example 19 and Comparative Examples 33 and 34 was removed by inverting the rice cooker pot onto a tray immediately after cooking. The rice near the sides of the pot was removed and set aside at the edge of the tray. The rice was leveled, a small gap was left, and it was covered with plastic wrap and allowed to cool at room temperature for 15 minutes. The cooked rice was frozen in a deep freezer at -80°C. The following day, it was freeze-dried using a freeze-dryer (FDU-2100: Tokyo Rikakiki Co., Ltd.) to obtain the cooked rice (freeze-dried products) from Example 19 and Comparative Examples 33 and 34. The enzymes listed in Table 10 are as shown in Table 7.

[0088] [Table 10]

[0089] [Test Example 7] Animal study (in vivo): Effect of enzyme-treated rice on suppressing blood glucose elevation. The following method was used to measure blood glucose levels in rats after administering rice, and the effect of suppressing the rise in blood glucose levels was evaluated. The test substances were freeze-dried cooked rice (freeze-dried) from Example 19, Comparative Examples 33 and 34, which were ground using a mixer mill (MM301: Verder Scientific), dispensed into standing pouches, sealed, stored at room temperature, and used for animal testing.

[0090] The total sugar content analysis of enzyme-treated rice was commissioned to the Japan Food Research Laboratories and measured using the phenol-sulfuric acid method. The test substance was prepared as a solution in distilled water on the day of the blood glucose measurement test. Blood glucose levels were measured at fasting, 15 minutes, 30 minutes, 60 minutes, 90 minutes, and 120 minutes after administration, according to the blood glucose measurement method described below and the test schedule in Figure 1. The test substance was administered orally at a total glucose content of 1.3 g / 20 mL / kg.

[0091] (Method for measuring blood glucose levels) Although various glucose tolerance tests have been conducted on rats, this test was carried out by modifying the method described in Japanese Patent Publication No. 2005-328776. [animal] Animal species and strain: rat, Crl:WI(Han) Gender: Male Age at arrival: 7 weeks old [Living environment] Temperature: 22±3℃ Humidity: 50±5% Lighting time: 12 hours / day [feed] Type: CRF-1 (Oriental Yeast Co., Ltd.) Feeding method: Feed freely except during fasting periods. [Drinking water] Type: Tap water Watering method: Water will be provided freely throughout the trial period. [Selection and grouping of animals] Animals used in the study will be selected from those that showed no abnormalities in general condition during the quarantine and acclimatization period. The animals will be used between 9 and 13 weeks of age. On the last day of quarantine and acclimatization, their body weight will be measured, and based on this weight, they will be assigned to groups of 6 animals using a stratified continuous randomization method. [Fasting treatment] Start fasting overnight the evening before the glucose tolerance test. [Measuring blood glucose levels] The vein at the tip of the tail is incised using a scalpel under unanesthetized conditions. Blood leaking from the incision is used for testing (blood glucose level). The blood glucose level is measured using an Accu-Chek self-testing glucose meter, and the displayed value is recorded. This is considered the fasting blood glucose level. The same glucose meter was used for all tests conducted on the same day.

[0092] The evaluation criteria were calculated as follows: Fasting blood glucose level was defined as the blood glucose level at 0 minutes. The value obtained by subtracting the blood glucose value at time 0 from the blood glucose value at each measurement time was defined as "Δ blood glucose value (mg / dL)". The highest value among the Δblood glucose levels at each measurement time was defined as "ΔCmax (mg / dL)" for each individual. The value obtained by calculating the area under the Δblood glucose elevation curve was defined as "Δblood glucose AUC (mg / dL·min)". The calculation method followed the method of the Japan Glycemic Index Research Society. The effect of suppressing blood glucose elevation was evaluated based on the Δblood glucose AUC of the test substance administration groups (Example 19, Comparative Example 34) when the Δblood glucose AUC of the control group (Comparative Example 33) was set to 100. The test results are shown in Table 11 and Figure 3.

[0093] [Table 11]

[0094] Comparative Example 33 is cooked rice without added enzymes, and is generally a food with a high glycemic index (GI). Comparative Example 34 is cooked rice with only MTT added as the enzyme. In Example 19, which used MTT and AG as enzymes in combination, the Δblood glucose AUC was lower compared to Comparative Examples 33 and 34, confirming a high blood glucose elevation suppression effect.

[0095] The above test results suggest that adding the specific enzyme combination of the present invention imparts indigestibility to cooked rice, and that this can be expected to have an effect in suppressing the rise in blood glucose levels from cooked rice. [Industrial applicability]

[0096] According to the present invention, it is possible to produce rice that can suppress the rise in blood glucose levels compared to rice without enzymes, and in particular, rice with a lower glycemic index.

[0097] This application is based on Japanese Patent Application No. 2020-073513, and its contents are entirely encompassed in this application.

Claims

1. A method for producing rice food or rice processed products that suppresses the rise in blood glucose levels, comprising the step of adding β-amylase and maltotriosyltransferase to raw rice as a raw material.

2. The manufacturing method according to claim 1, further comprising a rice cooking step following the step of adding the β-amylase and maltotriosyltransferase.

3. A method for producing rice food products or processed rice products with a reduced glycemic index, comprising the step of adding β-amylase and maltotriosyltransferase to raw rice as a raw material.

4. The manufacturing method according to claim 3, further comprising a rice cooking step following the step of adding the β-amylase and maltotriosyltransferase.

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