Method for producing starch-containing composition for freezing

Abstract

Provided is a novel technology for improving the freezing resistance of starch-containing foods.　Provided is a method for producing a starch-containing composition for freezing, the method including an enzymatic action step in which one or more enzymes selected from beta-amylase derived from a microorganism, beta-amylase derived from soybean, and 4-alpha-glucanotransferase are caused to act on a starch-containing material. The present technology also provides a method for producing a starch-containing composition, the method including a freezing step for freezing an enzyme-treated starch-containing composition obtained by causing one or more enzymes selected from beta-amylase derived from a microorganism, beta-amylase derived from soybean, and 4-alpha-glucanotransferase to act on a starch-containing material.

Description

Method for producing starch-containing compositions for freezing

[0001] The present technology relates to a method for producing a starch-containing composition for freezing. More specifically, the present technology relates to a method for producing a starch-containing composition for freezing, a method for producing a starch-containing composition, a method for improving the freeze resistance of a starch-containing composition, a method for maintaining or enhancing the sweetness of a starch-containing composition, an agent for improving the freeze resistance of a starch-containing composition, an agent for maintaining or enhancing the sweetness of a starch-containing composition, and a starch-containing composition.

[0002] In recent years, advances in preservation and distribution technologies have led to a global expansion of the market for frozen foods, beverages, and frozen confectioneries. However, it is known that foods containing a large amount of starch are subject to freezing damage, resulting in hardening and other physical properties when stored frozen. Against this background, technologies to improve the freeze resistance of starch-containing foods are being developed.

[0003] For example, Patent Document 1 discloses a technique for producing frozen gyuhi blocks that have significantly better resistance to cold thawing than conventional gyuhi blocks used as dough for producing rice cake-like foods. The gyuhi contains gelatinized starch, sugar, and α,α-trehalose, as well as maltose and / or α-maltosyl α,α-trehalose, and contains 150 to 400 parts by mass of sugars per 100 parts by mass of starch, calculated on anhydrous basis, and contains 30 to 250 parts by mass of sugar and 45 to 200 parts by mass of α,α-trehalose as sugars, as well as 45 to 250 parts by mass of maltose and / or 10 to 250 parts by mass of α-maltosyl α,α-trehalose.

[0004] Furthermore, Patent Document 2 discloses a technique for producing frozen ohagi that does not harden when frozen and does not drip when thawed, by carrying out the following steps: a step of steaming glutinous rice that has been washed and soaked in water for a required time; a step of adding a sugar solution and an anti-aging agent solution to the steamed rice immediately after steaming, and mixing and stirring the mixture in a vacuum pot; a step of further stirring and mixing while heated; a step of transferring the mixture to a container, covering it, and leaving it for at least two hours; a step of shaping the steamed rice that has been cooled to an appropriate temperature into an appropriate filling, wrapping it in bean paste, and finishing it into ohagi; and a step of flash-freezing the finished ohagi.

[0005] JP 2011-115157 A JP 2001-161277 A JP 2019-115361 A JP 9-107900 A

[0006] As mentioned above, technologies for improving the freeze resistance of starch-containing foods are being developed, but the problem of hardening due to repeated freezing and thawing still remains, and further improvements are required.

[0007] Therefore, the main object of the present technology is to provide a novel technology for improving the freeze resistance of starch-containing foods.

[0008] As a result of intensive research to solve the above-mentioned problems, the inventors of the present application found that even enzymes that are said to have the effect of preventing starch retrogradation (see, for example, Patent Documents 3 and 4) have different freeze resistance effects when repeatedly frozen and thawed depending on the type and origin of the enzyme, etc. They then succeeded in reliably improving the freeze resistance of starch-containing foods by using a specific enzyme, and completed the present technology.

[0009] That is, the present technology first provides a method for producing a starch-containing composition for freezing, which includes an enzymatic treatment step of treating a starch-containing material with one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase. The present technology also provides a method for producing a starch-containing composition, which includes a freezing step of freezing an enzyme-treated starch-containing composition obtained by treating a starch-containing material with one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase. The present technology also provides a method for producing a starch-containing composition, which includes an enzymatic treatment step of treating a starch-containing material with one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase, and a freezing step of freezing the enzyme-treated starch-containing composition. The present technology next provides a method for improving the freeze resistance of a starch-containing composition and a method for maintaining or enhancing the sweetness of a starch-containing composition, the method comprising: an enzymatic treatment step of treating a starch-containing material with one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase; and / or a freezing step of freezing an enzyme-treated starch-containing composition obtained by treating a starch-containing material with one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase. The present technology also provides an agent for improving the freeze resistance of a starch-containing composition and an agent for maintaining or enhancing the sweetness of a starch-containing composition, each containing one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase. In the present technology, the enzymes can be microbial β-amylase and / or 4-α-glucanotransferase. In this case, the β-amylase derived from the microorganism may be a β-amylase derived from a microorganism of the genus Bacillus. The present technology also provides a starch-containing composition using the freeze tolerance improver or sweetness maintaining or enhancing agent according to the present technology.

[0010] Preferred embodiments for carrying out the present technology will be described below. Note that the embodiments described below are examples of typical embodiments of the present technology, and the scope of the present technology should not be construed as being narrow.

[0011] 1. Method for producing a starch-containing composition for freezing, method for producing a starch-containing composition, method for improving the freeze resistance of a starch-containing composition, and method for maintaining or enhancing the sweetness of a starch-containing composition The method for producing a starch-containing composition for freezing, method for producing a starch-containing composition, method for improving the freeze resistance of a starch-containing composition, and method for maintaining or enhancing the sweetness of a starch-containing composition according to the present technology (hereinafter, these methods may be collectively referred to as "methods according to the present technology") include an enzyme action step and / or a freezing step. Furthermore, if necessary, a thawing step, a recovery step, or other steps commonly used in the production of foods and beverages can also be appropriately selected and performed. Below, the raw materials and enzymes used in the present technology, as well as each step, are described in detail.

[0012] (1) Raw materials In the method according to the present technology, a starch-containing material is used as a raw material. The starch content of the starch-containing material used in the present technology can be freely set as long as the function or effect of the present technology is not achieved. The lower limit of the starch content of the starch-containing material used in the present technology can be, for example, 10% by weight or more, 20% by weight or more, or 30% by weight or more. From the viewpoint of further enhancing the freeze resistance effect and the sweetness maintenance or enhancement effect, the upper limit of the starch content of the starch-containing material is preferably 45% by weight or more, 55% by weight or more, more preferably 65% ​​by weight or more, and even more preferably 75% by weight or more.

[0013] The upper limit of the starch content in the starch-containing material used in the present technology is, for example, 95% by weight or less, preferably 90% by weight or less, more preferably 85% by weight or less, and even more preferably 80% by weight or less, and may be 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, or 30% by weight or less.

[0014] The origin of the starch-containing material is not particularly limited as long as it does not achieve the function and effect of the present technology, and can be freely selected depending on the target starch-containing material. Examples include rice varieties such as Japonica rice, Indica rice, Javanica rice, and non-glutinous rice; wheat varieties such as oats, wheat, barley, and rye; potatoes such as potatoes, sweet potatoes, taro, Chinese yams, konjac potatoes, and cassava; legumes such as kudzu; and ferns such as bracken. The starch-containing material may be in the form of granules, powders, slurries, or liquids. Granular and powdery starch-containing materials are preferred. When using granular or powdery starch-containing materials, they are preferably mixed with an appropriate amount of water. Specific examples of powdery starch-containing materials include wheat flour, rice flour, potato starch, and kudzu starch.

[0015] (2) Microbial β-amylase and soybean-derived β-amylase The β-amylase (EC 3.2.1.2) used in the present technology is an exo-enzyme that sequentially degrades α-1,4 glycosidic bonds in starch starting from the non-reducing end with maltose (malt sugar) units. The present technology has found that among β-amylases, microbial β-amylase and soybean-derived β-amylase in particular have the effect of improving the freeze resistance of starch-containing compositions and enhancing the sweetness of starch-containing compositions.

[0016] Examples of β-amylases derived from microorganisms include β-amylases derived from microorganisms of the genus Bacillus (e.g., Bacillus flexus, Bacillus megaterium, Bacillus polymyxa, Bacillus circulans, etc.); Streptomyces sp.; Pseudomonas sp.; and the like.

[0017] These β-amylases derived from microorganisms and soybeans may be used alone or in combination of two or more kinds.

[0018] In the present technology, it is particularly preferable to use a β-amylase derived from a microorganism as the β-amylase, more preferably a β-amylase derived from the genus Bacillus, and even more preferably a β-amylase derived from Bacillus flexus. Here, "β-amylase derived from Bacillus flexus" refers to a β-amylase produced by a microorganism classified as Bacillus flexus (whether a wild-type strain or a mutant strain), or a β-amylase obtained by genetic engineering techniques using a β-amylase gene. Therefore, a recombinant produced by a host microorganism into which a β-amylase gene obtained from Bacillus flexus (or a gene obtained by modifying said gene) has been introduced also falls under the category of "β-amylase derived from Bacillus flexus."

[0019] Microbial and soybean-derived β-amylases can be prepared from the culture solution of soybeans or microorganisms from which they are derived. Specific preparation methods include recovering β-amylase from the culture solution or cells of soybeans or microorganisms. For example, when using a β-amylase-secreting microorganism, the cells can be recovered from the culture solution, if necessary, by filtration, centrifugation, or the like, and the enzyme can then be separated and / or purified. When using a non-β-amylase-secreting microorganism, the cells can be recovered from the culture solution, if necessary, and then disrupted by pressure treatment, ultrasonic treatment, or the like to extract the enzyme, after which the enzyme can be separated and / or purified. Methods for enzyme separation and / or purification include, without limitation, known protein separation and / or purification methods, such as centrifugation, UF concentration, salting out, and various chromatography methods using ion exchange resins. The separated and / or purified enzyme can be powdered by drying methods such as freeze-drying and vacuum drying, or by using appropriate excipients and / or drying aids in the drying methods. The isolated and / or purified enzyme can also be liquefied by adding an appropriate additive and sterilizing by filtration.

[0020] In this technology, not only natural (wild-type) β-amylase but also recombinant β-amylase obtained by genetic engineering techniques as described above can be used. Commercially available β-amylase or β-amylase preparations can also be used. An example of a commercially available β-amylase or β-amylase preparation is β-amylase derived from Bacillus flexus manufactured by Amano Enzyme Co., Ltd.

[0021] In the present technology, the amount of microbial β-amylase or soybean β-amylase used is not particularly limited as long as it does not impair the action and effect of the present technology. The lower limit of the amount of microbial β-amylase or soybean β-amylase used is, for example, 0.005 U or more per 1 g of starch. From the viewpoint of further enhancing the freeze tolerance effect and sweetness enhancing effect, the lower limit of the amount of microbial β-amylase or soybean β-amylase used is preferably 0.025 U or more, more preferably 0.05 U or more, even more preferably 0.4 U or more, even more preferably 0.7 U or more, and particularly preferably 1.0 U or more per 1 g of starch.

[0022] The upper limit of the amount of microbial β-amylase or soybean β-amylase used per 1 g of starch is, for example, 50 U or less, 30 U or less, 20 U or less, 10 U or less, 5.0 U or less, 3.0 U or less, 2.0 U or less, or 1.6 U or less.

[0023] In the present technology, the β-amylase activity is a value measured by the β-amylase activity measurement method described in the Examples below, and one unit (1 U) is defined as the amount of enzyme that causes an increase in reducing power equivalent to 1 mg of glucose per minute using a potato starch solution (pH 5.0) as a substrate.

[0024] (3) 4-α-Glucanotransferase The 4-α-glucanotransferase (EC 2.4.1.25) used in the present technology is an enzyme that catalyzes a chemical reaction in which a portion of 1,4-α-glucan is transferred to another portion of a carbohydrate such as glucose or 1,4-α-D-glucan. The type and origin of the 4-α-glucanotransferase used in the present technology are not particularly limited, as long as it acts on polysaccharides and oligosaccharides having an α-1,4 glycosidic bond and transfers a maltotriose unit to the saccharide.

[0025] The 4-α-glucanotransferase may be derived from either a plant or a microorganism. Examples of plant-derived 4-α-glucanotransferase include 4-α-glucanotransferase derived from potato (Solanum tuberosum L.) tubers. Examples of microorganism-derived 4-α-glucanotransferase include 4-α-glucanotransferase derived from actinomycetes (limited to Streptomyces avermitilis, Streptomyces cinnamoneus, Streptomyces griseus, Streptomyces thermoviolaceus, and Streptomyces violaceoruber) or bacteria (Agrobacterium radiobacter). radiobacter), Arthrobacter spp., Bacillus spp., Erwinia spp., Geobacillus pallidus, Geobacillus stearothermophilus, Gluconobacter oxydans, Leuconostoc mesenteroides, Paenibacillus alginolyticus, Pimelobacter spp., Protaminobacter spp., Pseudomonas spp., Serratia spp., Sporosarcina globispora Examples of suitable 4-α-glucanotransferases include those derived from the genera Bacillus globispora and Thermus, and Aeribacillus pallidus.

[0026] These 4-α-glucanotransferases may be used alone or in combination of two or more.

[0027] In the present technology, it is particularly preferable to use a 4-α-glucanotransferase derived from a microorganism as the 4-α-glucanotransferase, more preferably a 4-α-glucanotransferase derived from Aeribacillus, and even more preferably a 4-α-glucanotransferase derived from Aeribacillus pallidus. Here, "4-α-glucanotransferase derived from Aeribacillus pallidus" means a 4-α-glucanotransferase produced by a microorganism classified as Aeribacillus pallidus (which may be a wild-type strain or a mutant strain), or a 4-α-glucanotransferase obtained by genetic engineering techniques using a 4-α-glucanotransferase gene. Therefore, a recombinant produced by a host microorganism into which a 4-α-glucanotransferase gene obtained from Aeribacillus pallidus (or a gene obtained by modifying said gene) has been introduced also falls under the category of "4-α-glucanotransferase derived from Aeribacillus pallidus."

[0028] 4-α-Glucanotransferase can be prepared from the culture medium of the plant or microorganism from which it is derived. The specific preparation method is the same as the above-mentioned method for preparing β-amylase.

[0029] In this technology, not only natural (wild-type) 4-α-glucanotransferases but also recombinant 4-α-glucanotransferases obtained by genetic engineering techniques as described above can be used. Commercially available 4-α-glucanotransferases or 4-α-glucanotransferase preparations can also be used. An example of a commercially available 4-α-glucanotransferase or 4-α-glucanotransferase preparation is the 4-α-glucanotransferase derived from Aeribacillus pallidus manufactured by Amano Enzyme, Inc.

[0030] In the present technology, the amount of microbial 4-α-glucanotransferase used is not particularly limited as long as it does not impair the action and effect of the present technology. The lower limit of the amount of 4-α-glucanotransferase used is, for example, 0.05 U or more per 1 g of starch. From the viewpoint of further enhancing the freeze resistance effect and the sweetness-retaining effect, the lower limit of the amount of 4-α-glucanotransferase used is preferably 0.25 U or more, more preferably 0.5 U or more, even more preferably 1.75 U or more, and even more preferably 3.0 U or more per 1 g of starch.

[0031] The upper limit of the amount of 4-α-glucanotransferase used per gram of starch is, for example, 150 U or less, 100 U or less, 70 U or less, 50 U or less, 30 U or less, 20 U or less, 15 U or less, or 10 U or less.

[0032] In this technology, the 4-α-glucanotransferase activity is a value measured by the 4-α-glucanotransferase activity measurement method described in the Examples below, and one unit (1 U) is defined as the amount of enzyme that produces 1 μmol of glucose per minute when treated with maltotetraose as a substrate at pH 6.5 and 40°C.

[0033] (4) Enzyme Action Step The enzyme action step is a step in which one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase are allowed to act on the starch-containing material. These enzymes may be used alone or in combination of two or more. When two or more enzymes are used in combination, the two or more enzymes may be allowed to act on the starch-containing material simultaneously or separately. When two or more enzymes are allowed to act separately, the order in which they are allowed to act separately is not particularly limited. When two or more enzymes are allowed to act separately, an enzyme inactivation step may be carried out between the actions of each enzyme.

[0034] Various conditions for allowing the enzyme to act on a starch-containing material can be freely set as long as they do not impair the effects of the present technology. For example, the pH, temperature, and reaction time can be set depending on the physicochemical properties of the enzyme used, such as its optimal pH, stable pH range, optimal temperature, and temperature stability. Optimal reaction conditions can be determined through preliminary experiments.

[0035] When the microbial β-amylase and / or soybean-derived β-amylase is allowed to act on the starch-containing material, the pH can be set, for example, to 3.0 to 11.0, preferably 5.0 to 8.0, and more preferably 6.0 to 7.0. When the microbial β-amylase and / or soybean-derived β-amylase is allowed to act on the starch-containing material, the temperature can be set, for example, to 10° C. to 80° C., preferably 20° C. to 60° C., and more preferably 30° C. to 50° C. When the microbial β-amylase and / or soybean-derived β-amylase is allowed to act on the starch-containing material, the reaction time can be set, for example, to 5 minutes to 20 hours, 10 minutes to 10 hours, preferably 30 minutes to 5 hours, and more preferably 1 hour to 4 hours.

[0036] When 4-α-glucanotransferase is allowed to act on a starch-containing material, the pH can be set, for example, to 4.0 to 10.0, preferably 5.0 to 9.0, more preferably 5.0 to 8.0, or 5.0 to 7.0. When 4-α-glucanotransferase is allowed to act on a starch-containing material, the temperature can be set, for example, to 20° C. to 90° C., preferably 30° C. to 70° C., or more preferably 35° C. to 60° C. When 4-α-glucanotransferase is allowed to act on a starch-containing material, the reaction time can be set, for example, to 5 minutes to 20 hours, 10 minutes to 10 hours, preferably 30 minutes to 5 hours, or more preferably 1 hour to 4 hours.

[0037] (5) Freezing Step The freezing step is a step of freezing an enzyme-treated starch-containing composition obtained by allowing one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase to act on a starch-containing material.

[0038] The enzyme treatment step and the freezing step may be carried out in the same facility or in different facilities. For example, one facility may perform the enzyme treatment step and freeze the enzyme-treated starch-containing composition obtained, or one facility may distribute the enzyme-treated starch-containing composition obtained by performing the enzyme treatment step, and another facility may perform the step of freezing the enzyme-treated starch-containing composition.

[0039] The conditions for the freezing step are not particularly limited as long as they do not impair the functions and effects of the present technology, and any general freezing method can be freely adopted, for example, a method of freezing at around −20° C.

[0040] (6) Thawing Step The thawing step is a step of thawing the frozen enzyme-treated starch-containing composition.

[0041] The enzyme treatment step, the freezing step, and the thawing step described above may be performed by the same institution or by different institutions. For example, one institution may freeze and store the enzyme-treated starch-containing composition obtained by performing the enzyme treatment step and then thaw it, or one institution may distribute the enzyme-treated starch-containing composition obtained by performing the enzyme treatment step, another institution may perform a step of freezing the enzyme-treated starch-containing composition and distribute the frozen enzyme-treated starch-containing composition, and yet another institution may thaw the frozen enzyme-treated starch-containing composition. Alternatively, the enzyme-treated starch-containing composition obtained by performing the enzyme treatment step may be frozen, and the frozen enzyme-treated starch-containing composition may be distributed, and consumers who purchase the frozen enzyme-treated starch-containing composition may thaw it.

[0042] The specific method for the thawing step is not particularly limited as long as it does not impair the action and effect of the present technology, and any common thawing method can be freely adopted, such as thawing at room temperature, thawing at refrigeration temperature, thawing in running water, microwave heating, thawing in a hot water bath, steaming, boiling, baking, or other heating methods.

[0043] (7) Recovery Step The recovery step is a step of recovering the starch-containing composition or the starch-containing composition for freezing that has been produced through the enzymatic action step and / or the freezing step, and, if necessary, the thawing step. As for the specific recovery method, depending on the type of the starch-containing composition or the starch-containing composition for freezing to be produced, one or more recovery methods generally used in the production of starch-containing compositions or starch-containing compositions for freezing can be freely combined and used.

[0044] The method according to the present technology described above can be embodied as including the following steps (1) to (6): (1) preparing a starch-containing material; (2) allowing one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase to act on the prepared starch-containing material; (3) inactivating the enzyme; (4) freezing an enzyme-treated starch-containing composition obtained by allowing one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase to act on the starch-containing material; (5) thawing the frozen enzyme-treated starch-containing composition; and (6) recovering the produced starch-containing composition or the starch-containing composition for freezing.

[0045] Either or both of steps (2) and (4) may be performed. Steps (3), (5), and (6) are not essential and can be performed as needed. When multiple enzymes are used in step (2), an enzyme inactivation step (3) may be performed between the actions of each enzyme.

[0046] 2. Agent for Improving Freeze Tolerance of Starch-Containing Composition, and Agent for Maintaining or Enhancing Sweetness of Starch-Containing Composition The agent for improving freeze tolerance of a starch-containing composition and the agent for maintaining or enhancing sweetness of a starch-containing composition according to the present technology contain one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase. Other enzymes and other components may also be contained as necessary. Details of the β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase are the same as those of the enzymes used in the method according to the present technology described above, and therefore will not be described here.

[0047] (1) Other Components The freeze resistance improver for starch-containing compositions and the sweetness maintaining or enhancing agent for starch-containing compositions according to the present technology can be used in combination with other components, as long as they do not impair the action or effect of the present technology. Examples of other components that can be used include excipients, pH adjusters, colorants, flavoring agents, disintegrants, lubricants, stabilizers, enzymes, and other components that are commonly used in formulations. Furthermore, components with known or future functions can also be used in combination as appropriate depending on the purpose.

[0048] 3. Starch-containing composition, starch-containing composition for freezing A starch-containing composition or a starch-containing composition for freezing produced using the method according to the present technology or the agent for improving the freeze resistance of a starch-containing composition or the agent for maintaining or enhancing the sweetness of a starch-containing composition according to the present technology is characterized by having higher freeze resistance than a starch-containing composition or a starch-containing composition for freezing produced by a general method.

[0049] Furthermore, a starch-containing composition or a starch-containing composition for freezing produced using the method according to the present technology or the agent for improving the freezing tolerance of a starch-containing composition or the agent for maintaining or enhancing the sweetness of a starch-containing composition according to the present technology can maintain a sweetness equivalent to that of a starch-containing composition or a starch-containing composition for freezing produced by a general method, and, if necessary, can have a sweetness that is stronger than that of a starch-containing composition or a starch-containing composition for freezing produced by a general method.

[0050] For example, when 4-α-glucanotransferase is used as the enzyme, the sweetness can be maintained, i.e., the freeze resistance can be improved without affecting the taste such as sweetness. For example, when β-amylase derived from a microorganism or β-amylase derived from soybeans is used as the enzyme, in addition to improving the freeze resistance, the sweetness can also be enhanced.

[0051] The starch-containing composition and the starch-containing composition for freezing according to the present technology can be suitably used for a variety of purposes, for example, in foods and beverages.

[0052] Examples of foods and beverages include Japanese sweets (rice cakes, manju, daifuku, castella, etc.), Western sweets (cakes, donuts, pies, pastries, etc.), prepared foods (cooked rice, rice balls, grilled rice balls, fried rice, pilaf, paella, Chinese buns, takoyaki, okonomiyaki, etc.), breads (leavened bread, unleavened bread, yeast bread, unleavened bread (soda bread, etc.), bread containing wheat flour, bread not containing wheat flour (e.g., potato, rice, rye, etc.), gluten-free bread, etc.).

[0053] The distribution form of the starch-containing composition and starch-containing composition for freezing according to the present technology is not particularly limited, as long as it undergoes a freezing process at any point from production to consumption. For example, it can be distributed in a frozen state, a refrigerated state, a chilled state, or at room temperature. Furthermore, a starch-containing composition or a starch-containing composition for freezing that has been stored frozen, refrigerated, chilled, or at room temperature may be cooked by heating in a store or the like and distributed as a cooked starch-containing composition.

[0054] The present invention will be described in more detail below with reference to examples. Note that the examples described below are representative examples of the present invention and should not be construed as narrowing the scope of the present invention.

[0055] 1. Raw Materials The raw materials and enzymes used in the examples are shown in Table 1 below.

[0056]

[0057] 2. Enzyme Activity Measurement Method [β-Amylase Activity Measurement Method] Measurements were performed according to the method described in the Japanese Standards for Food Additives (9th edition). Specifically, potato starch was used as the substrate. It was pre-dried at 105°C for 2 hours. 1.0 g of the dried material was weighed out, 20 mL of water was added, and 5 mL of sodium hydroxide TS (2 mol / L) was gradually added with stirring to form a paste. The mixture was then heated in a water bath with stirring for 3 minutes, after which 25 mL of water was added. After cooling, the mixture was neutralized with hydrochloric acid TS (2 mol / L) and hydrochloric acid TS (0.1 mol / L). 10 mL of 1 mol / L acetic acid / sodium acetate buffer (pH 5.0) was added, and water was added to a total volume of 100 mL to prepare the substrate solution. Ten mL of substrate solution was weighed and heated at 37°C for 10 minutes. 1 mL of sample solution was added and immediately shaken. After heating at the same temperature for 10 or 30 minutes, 4 mL of Fehling's TS solution was added and gently shaken. After heating in a water bath for 15 minutes, the mixture was cooled to below 25°C. 2 mL of 30% potassium iodide solution and 2 mL of sulfuric acid (1 → 6) were added to prepare the test solution. Fehling's TS solution was prepared immediately after use by mixing 1 volume of copper solution with 1 volume of alkaline tartrate solution, prepared by dissolving 34.66 g of fine copper(II) sulfate pentahydrate crystals in water to make 500 mL, and 173 g of sodium potassium (+)-tartrate tetrahydrate and 50 g of sodium hydroxide in water to make 500 mL. A separate comparison solution was prepared using 10 mL of water instead of the substrate solution, following the same procedure as for the test solution. The liberated iodine in the test solution and the control solution was titrated with 0.05 mol / L sodium thiosulfate solution. The endpoint was determined when 1-2 drops of soluble starch test solution were added as the titration approached the end point and the resulting blue color disappeared. The amount of enzyme that increases the reducing power equivalent to 1 mg of glucose per minute was defined as 1 unit (1 U), and this was calculated using the following formula:β-Amylase activity (U / g, U / mL) = amount of glucose (mg) × 1 / 10 × 1 / M Amount of glucose (mg) = (b - a) × 1.6 × f a: Titration value (mL) of enzyme reaction solution b: Titration value (mL) of blank solution 1.6: 1 mL of 0.05 mol / L sodium thiosulfate solution corresponds to 1.6 mg of glucose 1 / 10: Unit conversion coefficient for reaction time (minutes) M: Amount of sample (g or mL) in 1 mL of sample solution f: Factor of 0.05 mol / L sodium thiosulfate solution (for quantitation).

[0058] [Method for Measuring 4-α-Glucanotransferase Activity] 180 mg of maltotetraose (Hayashibara) was weighed and placed in a 20 mL volumetric flask. Approximately 15 mL of 10 mmol / L MES buffer (pH 6.5) was added to dissolve the maltotetraose. Once dissolved, 10 mmol / L MES buffer (pH 6.5) was added to the solution to make a final volume of 20 mL. This was used as the substrate solution. 2 mL of the substrate solution was placed in a test tube and allowed to stand at 40 ± 0.5°C for 10-15 minutes. 0.5 mL of the sample solution was then added, shaken well, and allowed to stand at 40 ± 0.5°C for exactly 60 minutes. After standing, the tube was placed in a boiling water bath, heated for exactly 5 minutes, and then cooled under running water. The glucose produced was quantified using a Labo Assay Glucose (Fujifilm Wako Pure Chemical Corporation). The Lab Assay Glucose kit consists of a coloring agent containing mutarotase, glucose oxidase, peroxidase, 4-aminoantipyrine, and ascorbic acid oxidase, and a buffer containing phosphate buffer (pH 7.1) and phenol. It can determine glucose concentration by measuring the red pigment produced by the oxidative condensation of phenol and 4-aminoantipyrine. Under these conditions, one unit of enzyme is defined as the amount of enzyme that produces 1 μmol of glucose per minute.

[0059] 3. Experimental Example (1) Method In this experimental example, mochi was produced as an example of a starch-containing composition. A steamer was filled slightly more than halfway with water, set on a gas stove, and ignited. 200 g of joshinko (rice flour) was weighed directly into the stainless steel bowl of a mixer, and the stainless steel bowl was placed in the mixer and mixed using the stirring blades. 155 g of water was gradually added while mixing. Once the steamer reached a boil, the starch-containing composition (mochi) was wrapped in a steaming cloth over the steamer and steamed over high heat for 15 minutes. The mixture was stirred again in the mixer for 10 minutes to ensure complete mixing. When the starch-containing composition (mochi) reached 65°C or below, an enzyme solution (5 mL) suspended in water was added. After stirring again in the mixer for 5 minutes to ensure complete mixing, the starch-containing composition (mochi) was packed uniformly into a glass petri dish, incubated at 37°C for 3 hours, and then heat-treated at 90°C for 10 minutes (enzyme inactivation step). The starch-containing composition (mochi) was left at room temperature until it reached 25°C, and then flour was applied to the top, and the stress of the starch-containing composition (mochi) was measured using a rheometer (manufactured by Sun Scientific Co., Ltd.). The starch-containing composition (mochi) was then frozen at -20°C. To evaluate the freeze resistance of the starch-containing composition (mochi), the frozen starch-containing composition (mochi) was thawed at room temperature, and the stress of the starch-containing composition (mochi) was measured using a rheometer (manufactured by Sun Scientific Co., Ltd.), and then refrozen at -20°C. This procedure was repeated three times.

[0060] (2) Sensory Evaluation The starch-containing composition (rice cake) produced above was subjected to three freeze-thaw cycles and the taste (increase or decrease in sweetness) was evaluated according to the following evaluation criteria: 0: No change (same as control) +: Slightly sweeter than control ++: Much sweeter than control

[0061] (3) The results are shown in Table 2 below.

[0062]

[0063] (4) Discussion As shown in Table 2, the stress of the untreated (control) samples increased with repeated freezing and thawing compared to the samples before freezing and thawing. Furthermore, after the second freeze-thaw, the samples hardened to the point that stress could not be measured. On the other hand, the enzyme-treated samples (Examples 1 to 4) maintained their softness without increasing stress even after repeated freeze-thawing compared to the control. Comparing the examples, Example 2, which used microbial β-amylase, and Examples 3 and 4, which used 4-α-glucanotransferase, showed higher freeze resistance effects than Example 1, which used soybean-derived β-amylase.

[0064] In the evaluation of sweetness, Examples 3 and 4, which used 4-α-glucanotransferase, showed results similar to those of the control example. On the other hand, Examples 1 and 2, which used β-amylase, were found to have enhanced sweetness compared to the control example. Based on these results, for applications where it is desired to enhance sweetness while improving freeze resistance, it is preferable to select soybean-derived β-amylase and / or microbial-derived β-amylase, while for applications where it is desired to improve freeze resistance without changing taste properties such as sweetness, it is preferable to select 4-α-glucanotransferase.

Claims

1. A method for producing a starch-containing composition for freezing, comprising an enzymatic action step of allowing one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase to act on a starch-containing material.

2. A method for producing a starch-containing composition, comprising a freezing step of freezing an enzyme-treated starch-containing composition obtained by treating a starch-containing material with one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase.

3. A method for producing a starch-containing composition, comprising: an enzyme treatment step of treating a starch-containing material with one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase; and a freezing step of freezing the enzyme-treated starch-containing composition.

4. A method for improving the freezing resistance of a starch-containing composition, comprising: an enzyme action step of allowing one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase to act on a starch-containing material; and / or a freezing step of freezing an enzyme-treated starch-containing composition obtained by allowing one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase to act on a starch-containing material.

5. A method for maintaining or enhancing the sweetness of a starch-containing composition, comprising: an enzyme action step of allowing one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase to act on a starch-containing material; and / or a freezing step of freezing an enzyme-treated starch-containing composition obtained by allowing one or more enzymes selected from microbial β-amylase, soybean-derived β-amylase, and 4-α-glucanotransferase to act on a starch-containing material.

6. An agent for improving the freeze resistance of a starch-containing composition, comprising one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase.

7. A sweetness maintaining or enhancing agent for a starch-containing composition, comprising one or more enzymes selected from microbial β-amylase, soybean β-amylase, and 4-α-glucanotransferase.

8. The manufacturing method according to any one of claims 1 to 3, the method for improving freeze tolerance according to claim 4, the method for maintaining or enhancing sweetness according to claim 5, the agent for improving freeze tolerance according to claim 6, or the agent for maintaining or enhancing sweetness according to claim 7, wherein the enzyme is β-amylase and / or 4-α-glucanotransferase derived from a microorganism.

9. The production method, method for improving freezing tolerance, method for maintaining or enhancing sweetness, agent for improving freezing tolerance, or agent for maintaining or enhancing sweetness, according to claim 8, wherein the microorganism is a Bacillus microorganism.

10. A starch-containing composition comprising the freeze tolerance improving agent according to claim 6 or the sweetness maintaining or enhancing agent according to claim 7.

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