Rice inhibiting blood glucose level elevation

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 cooked rice in which blood glucose level rise is suppressed, a method for imparting the effect of suppressing blood glucose level rise to cooked rice, an enzyme preparation for imparting the effect of suppressing blood glucose level rise to cooked rice, a method for producing cooked rice with a reduced glycemic index, a method for lowering the glycemic index of cooked rice, and an enzyme preparation for lowering the glycemic index of cooked 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 staple foods for the Japanese, tend to increase 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 cooked rice. For example, adding brown rice, dietary fiber, or indigestible dextrin to white rice is known, but this method has the problem of worsening the taste and color. High-amylose rice has also been developed, but this has problems with taste, limited production, and high costs.

[0003] Patent Document 1 discloses a method for producing resistant carbohydrates, characterized by a step of acting maltotriosyltransferase on carbohydrates. Patent Document 2 discloses a method for producing slow-digestion carbohydrates that do not change the GI value, characterized by a step of acting branching enzyme and exoamylase on carbohydrates. Non-Patent Document 1 discloses a method for producing resistant carbohydrates, characterized by a step of acting branching enzyme and amylomaltase on carbohydrates. Patent Document 3 discloses rice with an amylose content of 25% or more that suppresses blood glucose level rise. Patent Document 4 discloses a production method that exhibits a aging-inhibiting effect on starch-containing foods, characterized by adding branching enzyme and α-glucosidase to the raw materials. However, none of the above documents reports any knowledge that structural changes that affect digestibility can be imparted by the enzymatic reaction during the cooking process of cooked rice. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-214255 [Patent Document 2] International Publication No. 2018 / 123901 [Patent Document 3] Japanese Patent Application Laid-Open 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 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a method for producing a cooked rice food or processed rice product that can suppress an increase in blood sugar level, particularly a cooked rice food or processed rice product with a reduced glycemic index. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems and have found that adding a specific enzyme during cooking rice and allowing it to react with the starch in the rice makes it possible to produce cooked rice foods or processed rice products that can suppress an increase in blood glucose level, particularly cooked rice foods or processed rice products with a reduced glycemic index. Based on this finding, the present inventors have conducted further extensive research and have completed the present invention.

[0008] That is, the present invention provides the following. [1] A method for producing cooked rice food or processed rice product with suppressed blood glucose level rise (or cooked rice food or processed rice product with indigestibility), which includes a step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material. [2] The method of producing according to [1] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase. [3] The method for producing rice according to [1] or [2] above, further comprising a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

[0009] [4] A method for imparting the effect of suppressing blood glucose level rise to cooked rice foods or processed rice products (or a method for imparting indigestibility to cooked rice foods or processed rice products), which comprises the step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material. [5] The method described in [4] above, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase. [6] The method according to [4] or [5] above, which comprises a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

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

[0011]

[10] A method for producing cooked rice food or processed rice product with a reduced glycemic index, comprising the step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material.

[11] The method of producing according to

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

[12] The method for producing rice according to

[10] or

[11] above, further comprising a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

[0012]

[13] A method for lowering the glycemic index of cooked rice foods or processed rice products, comprising the step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material.

[14] The method described in

[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 comprises a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

[0013]

[16] An enzyme preparation containing exoamylase and 4-α-glucanotransferase for reducing the glycemic index of cooked rice foods or processed rice products.

[17] The enzyme preparation described in

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

[18] An enzyme preparation according to

[16] or

[17] above for use in a rice cooking process.

[0014]

[19] A method for producing a cooked rice food or processed rice product with suppressed blood sugar level rise (or a cooked rice food or processed rice product with indigestibility), comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

[20] The method of producing according to

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

[21] The method for producing rice 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 the effect of suppressing blood sugar level rise to a cooked rice food or a processed rice product (or a method for imparting indigestibility to a cooked rice food or a processed rice product), comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

[23] The method described in

[22] above, wherein the 4-α-glucanotransferase is at least one 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 (1) or (2) below, for imparting the effect of suppressing blood sugar rise to cooked rice foods or processed rice products (or for imparting indigestibility to cooked rice foods or processed rice products). (1) α-glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

[26] The enzyme preparation described in

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

[27] An enzyme preparation according to

[25] or

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

[0017]

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

[29] The method of producing according to

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

[30] The method for producing rice 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 cooked rice foods or processed rice products, comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

[32] The method described in

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

[33] The method according to

[31] or

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

[0019]

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

[35] The enzyme preparation described in

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

[36] An enzyme preparation according to

[34] or

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

[0020]

[37] A method for suppressing an increase in blood glucose level in a subject in need of suppression of an increase in blood glucose level, comprising administering to the subject a cooked rice food or a processed rice product produced by a method comprising the step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material.

[38] The method described in

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

[39] The method described in

[37] or

[38] above, wherein the cooked rice food or processed rice product is produced by a method including a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

[0021]

[40] A cooked rice food or processed rice product for use in suppressing an increase in blood glucose level, produced by a method comprising the step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material.

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

[40] or

[41] above, produced by a method including a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

[0022]

[43] Use of exoamylase and 4-α-glucanotransferase for producing cooked rice food or processed rice products using raw rice as a raw material for suppressing blood glucose level elevation.

[44] The use according to

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

[45] The use according to

[43] or

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

[0023]

[46] A method for suppressing an increase in blood glucose level in a subject in need of suppression of an increase in blood glucose level, comprising administering to the subject a cooked rice food or a processed rice product produced by a method comprising a step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

[47] The method described in

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

[48] ​​The method according to

[46] or

[47] above, wherein the cooked rice food or processed rice product is produced by a method including a rice cooking step following the step of adding the enzyme.

[0024]

[49] A cooked rice food or processed rice product for use in suppressing an increase in blood sugar level, produced by a method comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material: (1) α-glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

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

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

[51] The cooked rice food or processed rice product according to

[49] or

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

[0025]

[52] Use of the enzyme (1) or (2) below for producing cooked rice food or processed rice products using raw rice as a raw material for suppressing blood sugar level increases: (1) α-glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

[53] The use according to

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

[54] The use according to

[52] or

[53] above, wherein the enzyme is used in a 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 allowing it to react with the starch in the rice, cooked rice can be produced that can suppress the rise in blood glucose levels after eating compared to cooked rice to which no enzyme is added. According to the present invention, this production method can produce cooked rice with a lower glycemic index compared to cooked rice to which no enzyme is added. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 shows the test schedule for Test Example 1. [Figure 2] FIG. 2 shows the results of Test Example 2. [Figure 3] FIG. 3 shows the results of Test Example 7. DETAILED DESCRIPTION OF THE INVENTION

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

[0029] In the present invention, exo-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-amylases include α-glucosidase and β-amylase. These enzymes can be used alone or in combination of two or more.

[0030] The α-glucosidase (EC 3.2.1.20) used in the present invention is an enzyme that hydrolyzes non-reducing terminal α-1,4-glucosidic bonds to produce α-glucose. Among α-glucosidases, transglucosidase is preferred. Examples of α-glucosidase include enzymes commercially available from Amano Enzyme Co., Ltd. under the trade names "Transglucosidase 'Amano'" and "α-Glucosidase 'Amano'." Regarding the enzymatic activity of α-glucosidase, 1 ml of 1 mM α-methyl-D-glucoside was added to 1 ml of 0.02 M acetate buffer (pH 5.0), and 0.5 ml of enzyme solution was added. The mixture was allowed to react at 40°C for 60 minutes. The amount of enzyme required to produce 1 μg of glucose in 2.5 ml of reaction solution was defined as 1 U (unit).

[0031] The β-amylase used in the present invention is an exoenzyme that has the activity of hydrolyzing every other α-1,4-glucosidic bond in starch (in maltose units) from the non-reducing end, and is known to be derived from a variety of sources, including microbial and plant sources. However, the β-amylase used in the present invention is not particularly limited in origin as long as it has the above-mentioned activity, and any β-amylase from any source can be used, and recombinant enzymes may also be used. The β-amylase used in the present invention may be a commercially available product, and specific examples include Himaltosin GL, Himaltosin GLH (both manufactured by HI, Inc.), and β-amylase F "Amano" (manufactured by Amano Enzyme Inc.). In the present invention, the activity unit of β-amylase is measured and defined as follows. p-Nitrophenyl-β-D-maltotrioside (PNP-β) is used as a substrate and treated with β-amylase. The amount of p-nitrophenol (PNP) produced is then measured by absorbance at 400 nm. The amount of enzyme required to dissociate 1 μmole of PNP per minute is defined as 1 U (unit).

[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 units from the non-reducing end of a donor molecule to an acceptor molecule. In the present invention, examples of 4-α-glucanotransferase include maltotriosyltransferase and amylomaltase. These enzymes can be used alone or in combination of two or more.

[0033] In the present invention, maltotriosyltransferase (EC2.4.1.25) is an enzyme that acts on polysaccharides and oligosaccharides having an α-1,4 glycoside bond as the bonding mode, and transfers a maltotriose unit to the saccharide. The enzymatic activity of the maltotriosyltransferase used in the present 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 from maltotetraose per minute when reacted for 60 minutes at pH 6.5 and 40° C. Note that the enzymes commercially available from Amano Enzyme Inc. under the trade names "Glycotransferase" and "Glycotransferase 'Amano' L" are examples of maltotriosyltransferase.

[0034] In the present invention, amylomaltase (EC 2.4.1.25) 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 an α-glucan (e.g., amylose, amylopectin, starch, etc.) to the non-reducing end of another α-glucan (or glucose). The donor molecule and acceptor molecule of the α-glucan chain may be the same, in which case intramolecular transfer occurs and the product has a cyclic structure. In the present invention, amylomaltase activity units are 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 method equivalent thereto. Specifically, it is measured and defined as follows: 1 mL of a reaction solution containing 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 terminate the reaction. Then, 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 calculated by subtracting the measurement value when the enzyme is used from the measurement value when the enzyme is not used (control), and the amount of enzyme that reduces the absorbance at 600 nm by 1 per minute is defined as 1 U (unit). In the present invention, amylomaltase includes amylomaltase derived from Corynebacterium sp.

[0035] The present invention relates to a method for producing cooked rice foods or processed rice products in which blood glucose level increases are suppressed, the method comprising the step of adding the following enzyme (1), (2), or (3) to raw rice as a raw material: (1) α-glucosidase and branching enzyme (sometimes referred to as enzyme (1) in this specification) (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase (sometimes referred to as enzyme (2) in this specification). (3) Exo-amylase and 4-α-glucanotransferase (sometimes referred to as enzyme (3) in this specification).

[0036] In the present invention, examples of the enzyme (2) include the following (2-i) to (2-iii): (2-i) α-Glucosidase, branching enzyme, and maltotriosyltransferase (2-ii) α-glucosidase, branching enzyme, and amylomaltase (2-iii) α-glucosidase, branching enzyme, maltotriosyltransferase, and amylomaltase

[0037] In the present invention, examples of the enzyme (3) include 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 the present invention is raw rice. There are no particular limitations on the variety of raw rice or whether it has been polished or not, and examples of the raw rice include polished rice, brown rice, germinated brown rice, high-amylose rice, and low-amylose rice. In the present invention, examples of cooked rice foods include cooked rice (white rice, brown rice, germinated brown rice, high-amylose rice, low-amylose rice, rice with added barley, rice with added glutinous barley, rice with added grains, and rice with added resistant carbohydrates), vinegared rice (sushi rice), red rice, pilaf, fried rice, seasoned rice, steamed sticky rice, rice porridge, risotto, rice balls, sushi, and boxed lunches. In the present invention, examples of processed rice products include rice crackers, okaki (rice crackers), Japanese sweets, and mochi (rice cakes). Also included are frozen, aseptically packaged, retort-pouched, dried, and canned versions of these products. In this specification, food is a concept that broadly encompasses anything that can be taken orally (excluding pharmaceuticals), and includes not only so-called "food" but also beverages, health supplements, health functional foods (e.g., foods for specified health uses, foods with functional claims, foods with nutrient functions), 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 raw raw rice before cooking and react with the starch in the rice during the cooking process. The enzymes can be added to the raw raw rice at any stage before cooking. These enzymes can be added to the soaking liquid in which the raw raw rice is soaked to absorb water, but it is preferable to add the enzymes after soaking and before cooking. Furthermore, in the present invention, multiple enzymes are used in combination, and the order in which these enzymes are added to the rice is not particularly important. One enzyme can be added first, followed by the remaining enzyme, but it is preferable to add multiple enzymes simultaneously. Furthermore, ingredients commonly used in foods can also be used in combination.

[0040] Enzymes (1): α-glucosidase and branching 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 in terms of enzyme activity per 1 g of raw rice. In the present invention, when enzyme (1) is used, the amount of branching 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. The ratio of the amounts of α-glucosidase and branching enzyme added (α-glucosidase:branching enzyme) is preferably 1U:1×10 -3 ~6×10 7 U, more preferably 1U:1×10 -2 ~6×10 6 U, more preferably 1U:1×10 -1 ~6×10 5 U, particularly preferably 1U: 1 to 6 × 10 4 It's U.

[0041] Enzymes (2): α-glucosidase, branching enzyme, 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 in terms of enzyme activity per 1 g of raw rice. In the present invention, when enzyme (2) is used, the amount of branching 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 enzyme (2) is used, the amount of 4-α-glucanotransferase (e.g., maltotriosyltransferase, amylomaltase) added is preferably 0.00005 to 100 U, more preferably 0.0001 to 30 U, even more preferably 0.005 to 10 U, and particularly preferably 0.01 to 4 U in terms of enzyme activity per 1 g of raw rice. The ratio of the amounts of α-glucosidase, branching enzyme, and 4-α-glucanotransferase (e.g., maltotriosyltransferase, amylomaltase) added (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 1U:1×10 -2 ~6×10 6 U:1×10 -4 ~4×10 4 U, more preferably 1U:1×10 -1 ~6×10 5 U:1×10 -3 ~4×10 3 U, particularly preferably 1U: 1 to 6 × 10 4 U:1×10 -2 ~4×10 2 It's U. In the enzyme (2), only one type of 4-α-glucanotransferase may be used, or multiple types of 4-α-glucanotransferases may be used in combination. When multiple types of 4-α-glucanotransferases are used in combination as enzyme (2), the amount added may be such that the "amount of each enzyme added" of the multiple types of 4-α-glucanotransferases falls within the range described above.

[0042] Enzyme (3): Exo-amylase and 4-α-glucanotransferase In the present invention, when enzyme (3) is used, the amount of exo-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 in terms of enzyme activity 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 in terms of enzyme activity per 1 g of raw rice. Furthermore, the ratio of the amount of exo-amylase (e.g., α-glucosidase, β-amylase) to the amount of 4-α-glucanotransferase (e.g., maltotriosyltransferase, amylomaltase) added (exo-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 the enzyme (3), each of the exo-amylase and the 4-α-glucanotransferase may be used alone or in combination of two or more kinds. When multiple types of exo-amylases are used in combination as enzyme (3), the amount added may be any amount as long as the "amount of each enzyme added" of the multiple types of exo-amylases is within the range described above.Furthermore, when multiple types of 4-α-glucanotransferases are used in combination, the amount added may be any amount as long as the "amount of each enzyme added" of the multiple types of 4-α-glucanotransferases is within the range described above.

[0043] The reaction time for each enzyme is not particularly limited as long as it is long enough for the enzyme to act on the starch in rice, which is its substrate, but a practical reaction time is preferably 5 minutes to 24 hours. The reaction temperature is also not particularly limited as long as it is within a range in which the enzyme maintains its activity, but a practical temperature range of 0 to 100°C is preferred. In other words, by using these enzymes in a normal rice cooking process, sufficient reaction time and reaction temperature can be obtained to achieve the effects of the present invention. In the present invention, the rice cooking step preferably includes a step of raising the temperature from room temperature to 100°C after adding the enzyme, taking into consideration the enzyme reaction time, preferably over 5 to 60 minutes, more preferably 10 to 50 minutes, even more preferably 10 to 30 minutes, and even more preferably about 10 minutes. When the temperature reaches 100°C, the enzyme is inactivated and the enzymatic reaction is terminated. This is usually followed by a continuous boiling step (for example, 15 to 30 minutes, preferably about 15 to 20 minutes) and a steaming step (for example, 10 to 40 minutes, preferably about 10 to 20 minutes), to produce cooked rice of the present invention with suppressed rise in blood glucose level (cooked rice with a reduced glycemic index). In the present invention, the rice cooking step is carried out for, 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 conventional techniques in that the effects can be obtained even when the rice cooking step is completed in a short time (for example, about 1 hour) after the enzyme is added. In the present invention, the rice cooking step may be carried out using a commercially available rice cooker.

[0044] The production method of the present invention may include steps other than the above steps (for example, a drying step, a freeze-drying step) as long as the effects of the present invention are not impaired.

[0045] According to the production method of the present invention described above, cooked rice in which the increase in blood glucose level is suppressed (cooked rice with a reduced glycemic index) can be produced. In the present invention, the inhibitory effect on blood glucose level increase can be evaluated by measuring blood glucose levels over time 2 hours after administration (ingestion), for example, using the methods of Test Examples 1 and 7 described below or methods similar thereto, calculating the Δblood glucose AUC value, and comparing it with the Δblood glucose AUC value of a control (no enzyme added). The cooked rice produced by the production method of the present invention has a Δblood glucose AUC value of less than 100, preferably 95 or less, even more preferably 90 or less, and even more preferably 85 or less, when the Δblood glucose AUC of the control (no enzyme added) is taken as 100.

[0046] The cooked rice food or processed rice food produced by the manufacturing method of the present invention described above has the effect of suppressing blood glucose level rise in a subject (e.g., human) who ingests (administers) it, compared to when a cooked rice food or processed rice food without added enzymes is ingested (administered). In one aspect, the present invention relates to "a method for suppressing an increase in blood glucose level in a subject in need of suppression of an increase in blood glucose level, comprising administering to the subject a cooked rice food or processed rice product produced by a method comprising the step of adding enzyme (1), enzyme (2) or enzyme (3) to raw rice as a raw material," "a cooked rice food or processed rice product produced by a method comprising the step of adding enzyme (1), enzyme (2) or enzyme (3) to raw rice as a raw material, for use in suppressing an increase in blood glucose level," and "use of enzyme (1), enzyme (2) or enzyme (3) for producing a cooked rice food or processed rice product for suppressing an increase in blood glucose level using raw rice as a raw material."

[0047] The present invention relates to a method for imparting an effect of suppressing blood glucose level rise to a cooked rice food or a processed rice product, which method comprises the step of adding enzyme (1), enzyme (2) or enzyme (3) to raw rice as a raw material. In the method of the present invention for imparting the effect of suppressing an increase in blood glucose level, the amounts, ratios, and methods of addition of enzymes (1), (2), and (3) are the same as those described in the method of producing cooked rice foods or processed rice products of 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 level rise to cooked rice foods or processed rice products. In the enzyme preparation of the present invention, the content ratio of the enzyme is the same as the ratio of the amount of enzyme added explained in the method for producing cooked rice food or processed rice product of the present invention. The enzyme preparation of the present invention can be added to raw raw rice and reacted in accordance with the method described above in the method for producing cooked rice foods or processed rice products of the present invention, thereby imparting the effect of suppressing blood sugar level increases to cooked rice foods or processed rice products.

[0049] In addition to Enzymes (1), (2), and (3), the enzyme preparation of the present invention may further contain excipients such as dextrin, starch, modified starch, indigestible dextrin, reduced maltose, etc., seasonings such as meat extract, proteins such as vegetable protein, gluten, egg white, gelatin, and casein, protein hydrolysates, partial protein hydrolysates, emulsifiers, chelating agents such as citrates and polymerized phosphates, reducing agents such as glutathione and cysteine, and other food additives such as alginic acid, alkaline water, oils and fats, colorants, acidulants, flavorings, etc. The enzyme preparation of the present invention may be in any form, such as a liquid, paste, granules, or powder.

[0050] The present invention also relates to a method for producing a cooked rice food or processed rice product with a reduced glycemic index, which comprises the step of adding enzyme (1), enzyme (2), or enzyme (3) to raw raw rice; and a method for reducing the glycemic index of a cooked rice food or processed rice product, which comprises the step of adding enzyme (1), enzyme (2), or enzyme (3) to raw raw rice. In the method for producing cooked rice foods or processed rice products with a reduced glycemic index of the present invention; the method for reducing the glycemic index of cooked rice foods or processed rice products; the amounts, ratios, and methods of addition of enzymes (1), (2), and (3) are the same as those described above in the method for producing cooked rice foods or processed rice products of the present invention.

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

[0052] In the present invention, the glycemic index (GI) value can be calculated and the reference diet can be prepared as follows. [How to calculate GI value] First intake of the reference meal: Consume cooked rice equivalent to 50g of carbohydrates, and measure blood glucose levels by fingertip blood sampling in the fasting state and 15, 30, 45, 60, 90, and 120 minutes after ingestion. Second intake of the reference meal: Eat cooked rice equivalent to 50g of carbohydrates, and measure blood glucose levels in the same way as the first intake. Setting of reference value: The area under the blood glucose curve (IAUC) of two standard meals is calculated, and subjects with a difference in area within 25% are selected, and the area under the blood glucose curve (IAUC) is averaged to set the reference value. Intake of the test meal: Blood glucose levels are measured by fingerstick blood sampling at fasting time 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 this value relative to the reference value is taken as the GI value. Other regulations will be implemented in accordance with the protocol established by the Japan Glycemic Index Study Group (http: / / www.gikenkyukai.com / protocol.html). [Preparation of standard diet] The standard diet is made by cooking raw white rice (non-glutinous rice) with a water content of 135%, and the cooked rice provides the equivalent of 50g of carbohydrates per person.

[0053] As used herein, "reduced" glycemic index means that the glycemic index is lower than the glycemic index of a cooked rice food or processed rice product produced without the addition of enzymes. The glycemic index of cooked rice produced by the production method of the present invention (for example, cooked white rice, cooked rice made from a mixture of white rice and brown rice) is less than 100, preferably 95 or less, more preferably 90 or less, and 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 of a control (enzyme-free) is taken as 100. [Example]

[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 to 3, Comparative Examples 1 and 2] The raw material used was Hitomebore rice (raw rice) from Miyagi Prefecture. Brown rice was harvested on the same day from a single producer, polished on the same day, and placed in a light-blocking vacuum pack containing an oxygen absorber and refrigerated at 5°C until testing. The polished rice was allowed to return to room temperature 30 minutes before weighing on the day of cooking. The polished rice was weighed using an electronic balance (US6002S, Mettler-Toledo). The polished rice was placed in a colander and gently stirred clockwise 10 times in a bowl of tap water. The tap water was replaced and the same process was repeated five times. After washing, the rice was soaked in tap water for one hour. The rice was then removed from the colander and transferred to a rice cooker. Tap water was added to adjust the water content to 150% on the electronic balance. The rice cooker was then placed in a mini rice cooker (Koizumi Co., Ltd.: KSC-1511 / W). The enzymes were added in the amounts shown in Tables 1-1 and 1-2, and the rice was cooked to obtain the cooked rice of Examples 1 to 3. The cooked rice of Comparative Example 1 (Comparative Example 1-1 and Comparative Example 1-2) was obtained in the same manner as Example 1, except that the enzymes were not added. Cooked rice of Comparative Example 2 (Comparative Example 2-1, Comparative Example 2-2) was obtained in the same manner as Comparative Example 1, except that the raw material Hitomebore produced in Miyagi Prefecture was changed to Hoshiyutaka (high amylose rice). Immediately after cooking the cooked rice obtained in Examples 1 to 3 and Comparative Examples 1 and 2, the rice cooker was turned over onto a tray and the cooked rice was removed. The cooked rice closest to the wall of the rice cooker was removed and placed on the edge of the tray. The cooked rice was leveled, slightly spaced apart, wrapped in 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, the cooked rice was freeze-dried using a freeze dryer (FDU-2100: Tokyo Rikakiki Co., Ltd.) to obtain the cooked rice (freeze-dried products) of Examples 1 to 3 and Comparative Examples 1 and 2. Note that Preparations 1 and 2 shown in Tables 1-1 and 1-2 were prepared using the same method, with only differences 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 test (in vivo) - Blood sugar level suppression effect of enzyme-treated rice The blood glucose levels of rats were measured after administration of cooked rice using the following method, and the effect of suppressing an increase in blood glucose levels was evaluated. The test substances were the cooked rice (freeze-dried products) of Examples 1 to 3 and Comparative Examples 1 and 2, which were pulverized using a mixer mill (MM301: Verder Scientific), dispensed into standing pouches, sealed with a seal, stored at room temperature, and subjected to animal testing. Note that 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 the dates and test facilities.

[0060] The total sugar mass analysis of the enzyme-treated cooked rice was outsourced to the Japan Food Analysis Center, a general incorporated foundation, and was 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 in the fasting state and 15, 30, 60, and 120 minutes after administration according to the blood glucose measurement method described below and the test schedule shown in Figure 1. The test substance was administered orally at a total sugar content of 2 g / 20 mL / kg.

[0061] (Method of measuring blood glucose level) Various glucose tolerance tests have been conducted on rats, but this test was carried out using a modified version of the test described in Japanese Patent Laid-Open No. 2005-328776 (Patent Document 3). [animal] Animal species and strain: Rat, Slc:Wistar (SPF) Producer: Japan SLC Co., Ltd. Gender: Male Age at time of arrival: 6 weeks old Quarantine and acclimation: Animals are acclimated from the time of arrival until group allocation. However, the arrival date is counted as day 0 and the animals are quarantined for up to 7 days. General condition observations are conducted daily. [Breeding environment] Temperature: 22±3℃ Humidity: 50±20% Lighting time: 12 hours / day [feed] Type: Labo MR Stock solid feed (Nosan Corporation) or CRF-1 (Oriental Yeast Co., Ltd.) Feeding method: Feed ad libitum except during fasting periods. [Drinking water] Type: Tap water Water supply: Provide water ad libitum throughout the test period. [Animal selection and grouping] During the quarantine and acclimation period, animals to be used in the test will be selected from those that show no abnormalities in their general condition. Animals will be used at 7 weeks of age. On the final day of quarantine and acclimation, their body weight will be measured, and using this weight as an index, they will be allocated to groups of 6 to 10 animals using a stratified sequential randomization method. [Fasting treatment] An overnight fast will begin in the evening of the day before the glucose tolerance test. [Blood glucose measurement] The vein at the tip of the tail is incised using a scalpel blade without anesthesia. The blood leaking from the incision is used to perform the test (blood glucose level). The blood glucose level is measured using a self-testing glucose meter, "Accu-Check" or "Glutest Neo," and the blood glucose level displayed on the meter is recorded. This is the fasting blood glucose level. The same glucose meter was used for tests on the same day.

[0062] The evaluation items were calculated as follows. Fasting blood glucose level was defined as the blood glucose level at 0 min. The value obtained by subtracting the blood glucose level at 0 minutes from the blood glucose level at each measurement time was defined as "Δ blood glucose level (mg / dL)." The highest Δ blood glucose value at each measurement time was designated as the "ΔC max (mg / dL)". The area under the Δ blood glucose rise curve was calculated and used as the "Δ blood glucose AUC (mg / dL·min)." The calculation method followed the method of the Japan Glycemic Index Study Group. The effect of suppressing an increase in blood glucose level was evaluated based on the value of Δblood glucose AUC in the test substance administration group when the Δblood glucose AUC in the control group was set at 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 to which no enzymes are added, which is generally a food with a high GI value. Comparative Example 2 (Comparative Example 2-1, Comparative Example 2-2) is cooked rice made from high-amylose rice, which is described in JP 2005-328776 A (Patent Document 3) as having a low GI value. Compared with Comparative Example 1 (Comparative Example 1-1, Comparative Example 1-2), Comparative Example 2 (Comparative Example 2-1, Comparative Example 2-2) had a lower Δ blood glucose level AUC, confirming that blood glucose level elevation was suppressed. In Examples 1 to 3, the Δ blood glucose level AUC was lower than in Comparative Example 1 (Comparative Example 1-1, Comparative Example 1-2), confirming the suppression of blood glucose level rise. Furthermore, in Examples 2 and 3, the Δ blood glucose level AUC was lower than in Comparative Example 2 (Comparative Example 2-2), confirming that the blood glucose rise suppression effect was greater than that of existing technologies.

[0066] The above test results suggest that the addition of the specific enzyme combination of the present invention makes cooked rice indigestible, and is expected to have the effect of suppressing the rise in blood sugar levels due to cooked rice.

[0067] [Examples 4 and 5] The required amount of polished rice from Miyagi Prefecture, Hitomebore, was weighed and placed in a colander, then gently stirred clockwise 20 times in a bowl of tap water. The tap water was replaced and the same process was repeated five times. After washing, the polished rice was transferred to a rice cooker, and tap water was added until the weight of the rice was 235% of the weight of the raw rice (water addition ratio: 135% of the raw rice), and the rice was soaked for one hour. The rice cooker was placed in a household rice cooker (Mitsubishi IH rice cooker NJ-HS06), and the amount of enzyme shown in Table 4 was added. After gently stirring to distribute the enzyme uniformly, the rice was cooked in the rice cooking mode ("white rice" or "cooked rice, normal") to prepare the enzyme-treated cooked 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 cooked rice of Example 6 was prepared in the same manner as in Examples 4 and 5, except that the polished rice (Hitomebore produced in Miyagi Prefecture) was changed to a mixture of 75% polished rice (Hitomebore produced in Miyagi Prefecture) and 25% brown rice (Hitomebore brown rice produced in Miyagi Prefecture). Enzyme-free cooked rice of Comparative Example 3 was prepared in the same manner as in Example 6, except that no enzyme was added.

[0069] [Table 4]

[0070] [Table 5]

[0071] In Test Examples 2 and 3 described below, the glycemic index (GI) values ​​were calculated and the reference diets were prepared as follows. [How to calculate GI value] First reference meal intake: Rice equivalent to 50g of carbohydrates was consumed, and blood glucose levels were measured by fingertip blood sampling in the fasting state and 15, 30, 45, 60, 90, and 120 minutes after ingestion. Second intake of the reference meal: Rice equivalent to 50g of carbohydrates was consumed, and blood glucose levels were measured in the same way as the first intake. Setting of reference values: The area under the blood glucose curve (IAUC) for the two reference meals was calculated, and subjects with a difference in area within 25% were selected. The area under the blood glucose curve (IAUC) was averaged to set the reference value. Intake of the test meal: Blood glucose levels were measured by fingertip blood sampling at fasting time 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 meal was calculated, and the percentage of this value relative to the reference value was used as the GI value. Other regulations were implemented in accordance with the protocol established by the Japan Glycemic Index Study Group (http: / / www.gikenkyukai.com / protocol.html). [Preparation of standard diet] The reference diet consisted of cooked "Hitomebore" white rice (non-glutinous rice) from Miyagi Prefecture, prepared with a water content of 135%, with the cooked rice provided containing the equivalent of 50g of carbohydrates per person.

[0072] [Test Example 2] GI measurement of enzyme-treated cooked rice (white rice) The GI values ​​of 10 healthy adult males (mean age 33.9±6.9 years) whose area under the curve (IAUC) difference between the two intakes of the standard diet was within 25% were measured using the enzyme-treated cooked rice of Examples 4 and 5. A crossover test was conducted in which an interval of at least 24 hours was allowed between the intake of the enzyme-treated cooked rice of Example 4 and the intake of the enzyme-treated cooked rice of Example 5, and only the intake of the enzyme-treated cooked rice was crossed over. The enzyme-treated cooked rice was provided in an amount equivalent to 50 g of carbohydrates per person. As a result, the GI value of the group that ate the enzyme-treated cooked rice of Example 4 was 90±29 (mean value±standard deviation), and the GI value of the group that ate the enzyme-treated cooked rice of Example 5 was 87±33 (mean value±standard deviation). Furthermore, a stratified analysis was performed on subjects with little variation in the intake of the reference diet (the top half of subjects with little variation in maximum blood glucose level (Cmax) the second time they ingested the reference diet compared to the first time: N=5, average age 34.2±5.3 years). The GI value of the group that ingested the enzyme-treated cooked rice of Example 4 was 79±38 (mean±standard deviation), and the GI value of the group that ingested the enzyme-treated cooked rice of Example 5 was 71±31 (mean±standard deviation) (Figure 2).

[0073] [Test Example 3] Measurement of GI value of enzyme-treated mixed cooked rice (75% white rice, 25% brown rice) The GI values ​​were measured for 10 healthy adult males (average age 29.9±19.4 years) whose difference in area under the curve (IAUC) between the two intakes of the standard diet was within 25% for the group consuming cooked rice without added enzymes of Comparative Example 3 and the group consuming enzyme-treated cooked rice of Example 6. A crossover study was conducted with an interval of at least 24 hours between each period for the group consuming cooked rice without added enzymes of Comparative Example 3 and the group consuming enzyme-treated cooked rice of Example 6, with only the cooked rice consumed being crossed over and repeated. In both cases, the cooked rice was provided in an amount equivalent to 50 g of carbohydrates per person. As a result, the GI value of the group that ate the enzyme-free cooked rice of Comparative Example 3 was 81±20 (mean value±standard deviation), and the GI value of the group that ate the enzyme-treated cooked rice of Example 6 was 70±18 (mean value±standard deviation).

[0074] In Test Examples 2 and 3, a reduction in the GI value 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, suggesting that the enzyme composition (enzyme preparation) of the present invention has the effect of lowering the GI value of cooked rice foods or processed rice products.

[0075] [Test Example 4] Artificial digestion test Starch hydrolysate (dextrin) (substrate) was treated with the enzymes shown in Table 6 using the method described below, and the resulting carbohydrates were subjected to an artificial digestion test to examine whether or not the substrate was rendered indigestible. (1) Enzymatic preparation of carbohydrates The enzymes in the amounts shown in Table 6 below were added to starch hydrolysate (Pinex #100 (Matsutani Chemical Industry Co., Ltd.), final concentration 4% (w / v)) in 50 mmol / L phosphate buffer (pH 6.0). After overnight (17 hours) of reaction at 50°C, the reaction was stopped by boiling in a boiling water bath for 15 minutes to obtain the reaction solutions of Examples 7 to 12 and Comparative Examples 5 to 11. The solution of Comparative Example 4 (control) was also obtained in the same manner as Example 7, etc., except that no enzyme was added. The obtained reaction solutions of Examples 7 to 12, Comparative Examples 5 to 11, and Comparative Example 4 were cooled and used as samples for the artificial digestion test in (2) below. Separately, the amounts of free glucose in the reaction solutions obtained in Examples 7 to 12, Comparative Examples 5 to 11, and Comparative Example 4 were determined by the glucose oxidase method (Fujifilm Wako Pure Chemical Industries, Ltd.: Labo Assay™ Glucose). The amounts of free glucose obtained are referred to as "amounts of free glucose after enzyme reaction." The substrate (carbohydrate) after the enzyme reaction, excluding free glucose, is referred to as "enzyme-modified dextrin." The amount obtained by subtracting the "amount of free glucose after the enzyme reaction" from the amount of substrate before the enzyme reaction is referred to as the "amount of enzyme-modified dextrin." The amount of glucose released after the enzyme reaction per mL of reaction solution (amount of glucose released after the enzyme reaction (mg / mL)) and the amount of enzyme-modified dextrin per mL of reaction solution (amount of enzyme-modified dextrin (mg / mL)) were calculated and used to calculate the decomposition rate of the enzyme-modified dextrin below. The enzymes in Table 6 are as shown in Table 7.

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

[0077] The decomposition rates of the enzyme-modified dextrins in the reaction solutions of Examples 7 to 12 and Comparative Examples 5 to 11 obtained in (1) and the solution of Comparative Example 4 were calculated using the following formula. The results are shown in Table 6. (calculation formula) Decomposition rate of enzyme-modified dextrin (wt%) = {amount of glucose released after artificial digestion test (mg / mL) - amount of glucose released after enzyme reaction (mg / mL)} / amount of enzyme-modified dextrin (mg / mL)

[0078] [Table 6]

[0079] As shown in Table 6, it was confirmed that the decomposition rate of enzyme-modified dextrin was lower in Examples 7 to 12, in which AG and MTT were used in combination, compared to Comparative Example 4, in which no enzyme was added, Comparative Example 5, in which AG was used alone, and Comparative Examples 6 to 11, in which MTT was used alone. These results suggest that the combined use of exoamylase (AG) and 4-α-glucanotransferase (MTT) is effective in producing foods (foods made resistant to digestion) that can suppress blood glucose level increases 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, an artificial digestion test was conducted on the carbohydrates obtained by treating starch hydrolysate (dextrin) (substrate) with the enzymes shown in Table 8 to examine whether the substrate was rendered indigestible. The enzymes in Table 8 are as shown in Table 7 above.

[0082] [Table 8]

[0083] As shown in Table 8, it was confirmed that the decomposition rate of enzyme-modified dextrin was lower in Example 13, in which AG (exo-amylase) and MTT were used in combination, compared to Comparative Example 12, in which no enzyme was added, Comparative Example 13, in which AG alone was used, Comparative Examples 14 to 16, in which AA (endo-amylase) alone was used, Comparative Examples 17 to 19, in which AA and MTT were used in combination, Comparative Examples 20 to 22, in which MTH (endo-maltotriohydrolase) alone was used, and Comparative Examples 23 to 25, in which MTH and MTT were used in combination. These results suggest that among amylases, exoamylase (AG), when used in combination with 4-α-glucanotransferase (MTT), is effective in producing foods that can suppress blood sugar levels (foods that have been made indigestible).

[0084] [Test Example 6] Artificial digestion test An artificial digestion test was conducted on the carbohydrates obtained by treating starch hydrolysate (dextrin) (substrate) with the enzymes shown in Table 9 in the same manner as in Test Example 4, except that the process of "reacting overnight (17 hours) at 50°C, and then terminating the reaction by boiling in a boiling water bath for 15 minutes" in Test Example 4 was changed to "reacting for 4 hours at 50°C, and then terminating the reaction by boiling in a boiling water bath for 15 minutes" to examine whether the substrate was rendered indigestible. The enzymes in Table 9 are as shown in Table 7 above.

[0085] [Table 9]

[0086] As shown in Table 9, it was confirmed that the decomposition rate of enzyme-modified dextrin was lower in Examples 14 and 15, in which AG and MTT were used in combination, compared to Comparative Example 26, in which no enzyme was added, Comparative Examples 27 and 28, in which AG was used alone, and Comparative Example 29, in which MTT was used alone. Furthermore, it was confirmed that the decomposition rate of enzyme-modified dextrin was lower in Examples 16 to 18, in which BA and MTT were used in combination, compared to Comparative Example 26, in which no enzyme was added, Comparative Examples 30 to 32, in which BA was used alone, and Comparative Example 29, in which MTT was used alone. These results suggest that the combined use of exoamylase (AG, BA) and 4-α-glucanotransferase (MTT) is effective in producing foods (foods made resistant to digestion) that can suppress blood glucose level increases 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. Brown rice was harvested on the same day from a single producer, polished on the same day, and placed in a light-blocking vacuum pack containing an oxygen absorber and refrigerated at 5°C until testing. The polished rice was allowed to return to room temperature 30 minutes before weighing on the day of cooking. The polished rice was weighed using an electronic balance (US6002S, Mettler-Toledo). The polished rice was placed in a colander and gently stirred clockwise 10 times in a bowl of tap water. The tap water was replaced and the same process was repeated five times. After washing, the rice was soaked in tap water for one hour. The rice was then removed from the colander and transferred to a rice cooker. Tap water was added to adjust the water content to 135% on the electronic balance. The rice cooker was then placed in a household rice cooker (Mitsubishi: NJ-LH064). The enzymes were added in the amounts shown in Table 10, and the rice was cooked to obtain the cooked rice of Example 19 and Comparative Example 34. The cooked rice of Comparative Example 33 was obtained in the same manner as Example 19, except that the enzymes were not added. Immediately after cooking the cooked rice obtained in Example 19 and Comparative Examples 33 and 34, the rice cooker was turned over onto a tray and the cooked rice was removed. The cooked rice closest to the wall of the rice cooker was removed and placed on the edge of the tray. The cooked rice was leveled, slightly spaced apart, wrapped in plastic, and then allowed to cool at room temperature for 15 minutes. The cooked rice was frozen in a deep freezer at -80°C. The next day, the cooked rice was freeze-dried using a freeze dryer (FDU-2100: Tokyo Rikakiki Co., Ltd.) to obtain the cooked rice (freeze-dried products) of Example 19 and Comparative Examples 33 and 34. The enzymes in Table 10 are as shown in Table 7.

[0088] [Table 10]

[0089] [Test Example 7] Animal test (in vivo) - Blood sugar level suppression effect of enzyme-treated rice The blood glucose levels of rats were measured after administration of cooked rice using the following method, and the effect of suppressing an increase in blood glucose levels was evaluated. The test substances were the cooked rice (freeze-dried products) of Example 19 and Comparative Examples 33 and 34, which were pulverized using a mixer mill (MM301: Verder Scientific), dispensed into standing pouches, sealed with a seal, stored at room temperature, and subjected to animal testing.

[0090] The total sugar mass analysis of the enzyme-treated cooked rice was outsourced to the Japan Food Analysis Center, a general incorporated foundation, and was 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 in the fasting state and 15, 30, 60, 90, and 120 minutes after administration according to the blood glucose measurement method described below and the test schedule shown in Figure 1. The test substance was administered orally at a total sugar content of 1.3 g / 20 mL / kg.

[0091] (Method of measuring blood glucose level) Various glucose tolerance tests have been conducted on rats, but this test was conducted using a modified version of the method disclosed in JP-A-2005-328776. [animal] Animal species and strain: Rat, Crl:WI (Han) Gender: Male Age at time of arrival: 7 weeks old [Breeding environment] Temperature: 22±3℃ Humidity: 50±5% Lighting time: 12 hours / day [feed] Type: CRF-1 (Oriental Yeast Co., Ltd.) Feeding method: Feed ad libitum except during fasting periods. [Drinking water] Type: Tap water Water supply: Provide water ad libitum throughout the test period. [Animal selection and grouping] During the quarantine and acclimation period, animals that show no abnormalities in their general condition will be selected for use in the study. Animals will be used at 9 to 13 weeks of age. On the final day of quarantine and acclimation, their body weight will be measured, and using this weight as an index, they will be allocated to groups of 6 animals each using a stratified sequential randomization method. [Fasting treatment] An overnight fast will begin in the evening of the day before the glucose tolerance test. [Blood glucose measurement] The vein at the tip of the tail is incised using a scalpel blade without anesthesia. The blood leaking from the incision is used to perform a test (blood glucose level). The blood glucose level is measured using an "Accu-Check" self-testing glucose meter, and the blood glucose level displayed on the meter is recorded. This is considered the fasting blood glucose level. The same glucose meter was used for tests on the same day.

[0092] The evaluation items were calculated as follows. Fasting blood glucose level was defined as the blood glucose level at 0 min. The value obtained by subtracting the blood glucose level at 0 minutes from the blood glucose level at each measurement time was defined as "Δ blood glucose level (mg / dL)." The highest Δ blood glucose value at each measurement time was defined as each individual's ΔCmax (mg / dL). The area under the Δ blood glucose rise curve was calculated and used as the "Δ blood glucose AUC (mg / dL·min)." The calculation method followed the method of the Japan Glycemic Index Study Group. The effect of suppressing an increase in blood glucose level was evaluated from the value of 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 at 100. The test results are shown in Table 11 and FIG.

[0093] [Table 11]

[0094] Comparative Example 33 is cooked rice to which no enzymes were added, which is generally a food with a high GI value. Comparative Example 34 is cooked rice to which only MTT was added as an enzyme. Example 19, which used MTT and AG in combination as the enzymes, had a lower Δ blood glucose level AUC than Comparative Examples 33 and 34, confirming a high blood glucose elevation suppression effect.

[0095] The above test results suggest that the addition of the specific enzyme combination of the present invention makes cooked rice indigestible, and is expected to have the effect of suppressing the rise in blood sugar levels due to cooked rice. [Industrial Applicability]

[0096] According to the present invention, cooked rice that can suppress an increase in blood glucose level compared to cooked rice to which no enzymes are added, particularly cooked rice with a reduced glycemic index, can be produced.

[0097] This application is based on patent application No. 2020-073513 filed in Japan, the contents of which are incorporated in full herein.

Claims

1. A method for producing cooked rice food or processed rice product in which blood glucose level rise is suppressed, comprising the step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material.

2. The production method according to claim 1, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

3. The method according to claim 1 or 2, further comprising a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

4. A method for imparting the effect of suppressing blood glucose level rise to cooked rice foods or processed rice products, comprising the step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material.

5. The method according to claim 4, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

6. The method according to claim 4 or 5, further comprising a rice cooking step following the step of adding the exo-amylase and 4-α-glucanotransferase.

7. An enzyme preparation containing exo-amylase and 4-α-glucanotransferase for imparting the effect of suppressing blood glucose level rise to cooked rice foods or processed rice products.

8. The enzyme preparation according to claim 7, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

9. 9. The enzyme preparation according to claim 7 or 8, for use in a rice cooking process.

10. A method for producing cooked rice food or processed rice product with a reduced glycemic index, comprising the step of adding exo-amylase and 4-α-glucanotransferase to raw rice as a raw material.

11. The production method according to claim 10, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

12. The method according to claim 10 or 11, further comprising a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

13. A method for lowering the glycemic index of cooked rice foods or processed rice products, comprising the step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material.

14. The method according to claim 13, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

15. The method according to claim 13 or 14, further comprising a rice cooking step following the step of adding the exo-amylase and 4-α-glucanotransferase.

16. An enzyme preparation for lowering the glycemic index of cooked rice foods or processed rice products, which contains exo-amylase and 4-α-glucanotransferase.

17. The enzyme preparation according to claim 16, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

18. 18. An enzyme preparation according to claim 16 or 17 for use in a rice cooking process.

19. A method for producing a cooked rice food or processed rice product in which blood glucose level rise is suppressed, comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

20. The method according to claim 19, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

21. The method according to claim 19 or 20, further comprising a rice cooking step following the step of adding the enzyme.

22. A method for imparting the effect of suppressing blood sugar level rise to a cooked rice food or a processed rice product, comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

23. The method according to claim 22, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

24. 24. The method of claim 22 or 23, further comprising a rice cooking step following the step of adding the enzyme.

25. An enzyme preparation for imparting the effect of suppressing blood sugar level rise to cooked rice foods or processed rice products, comprising the enzyme (1) or (2) below: (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

26. The enzyme preparation according to claim 25, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

27. 27. An enzyme preparation according to claim 25 or 26 for use in a rice cooking process.

28. A method for producing a cooked rice food or processed rice product with a reduced glycemic index, comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

29. The production method according to claim 28, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

30. The method according to claim 28 or 29, further comprising a rice cooking step following the step of adding the enzyme.

31. A method for lowering the glycemic index of cooked rice foods or processed rice products, comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

32. The method according to claim 31, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

33. 33. The method of claim 31 or 32, further comprising a rice cooking step following the enzyme addition step.

34. An enzyme preparation for reducing the glycemic index of cooked rice foods or processed rice products, comprising the enzyme (1) or (2) below. (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

35. The enzyme preparation according to claim 34, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

36. 36. An enzyme preparation according to claim 34 or 35 for use in a rice cooking process.

37. A method for suppressing an increase in blood glucose level in a subject in need of suppression of an increase in blood glucose level, comprising administering to the subject a cooked rice food or a processed rice product produced by a method comprising a step of adding exoamylase and 4-α-glucanotransferase to raw rice as a raw material.

38. The method according to claim 37, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

39. The method according to claim 37 or 38, wherein the cooked rice food or processed rice product is produced by a method including a rice cooking step following the step of adding the exoamylase and 4-α-glucanotransferase.

40. A cooked rice food or processed rice product for use in suppressing an increase in blood glucose level, produced by a method including a step of adding exo-amylase and 4-α-glucanotransferase to raw rice as a raw material.

41. The cooked rice food or processed rice product according to claim 40, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

42. The cooked rice food or processed rice product according to claim 40 or 41, produced by a method including a rice cooking step subsequent to the step of adding the exoamylase and 4-α-glucanotransferase.

43. Use of exo-amylase and 4-α-glucanotransferase for producing cooked rice foods or processed rice products using raw rice as a raw material for suppressing an increase in blood sugar levels.

44. The use according to claim 43, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

45. The use according to claim 43 or 44, wherein the exo-amylase and 4-α-glucanotransferase are used in a rice cooking process.

46. A method for suppressing an increase in blood glucose level in a subject in need of suppression of an increase in blood glucose level, comprising administering to the subject a cooked rice food or a processed rice product produced by a method comprising a step of adding the enzyme (1) or (2) below to raw rice as a raw material. (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

47. The method of claim 46, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

48. 48. The method according to claim 46 or 47, wherein the cooked rice food or processed rice product is produced by a method including a rice cooking step following the step of adding the enzyme.

49. A cooked rice food or processed rice product for use in suppressing an increase in blood sugar level, produced by a method comprising the step of adding the enzyme (1) or (2) below to raw rice as a raw material: (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

50. The cooked rice food or processed rice product according to claim 49, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

51. 51. The cooked rice food or processed rice product according to claim 49 or 50, produced by a method including a rice cooking step subsequent to the step of adding the enzyme.

52. Use of the enzyme (1) or (2) below for producing a cooked rice food or processed rice product using raw rice as a raw material for suppressing blood sugar level elevation. (1) α-Glucosidase and branching enzyme (2) α-glucosidase, branching enzyme, and 4-α-glucanotransferase

53. The use of claim 52, wherein the 4-α-glucanotransferase is at least one selected from the group consisting of maltotriosyltransferase and amylomaltase.

54. 54. The use according to claim 52 or 53, wherein the enzyme is used in a rice cooking process.

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