Agent for preparing frozen processed food, frozen processed food, and method for producing frozen processed food

Abstract

The present invention addresses the problem of providing a novel means that, even when applied to a processed food having a delicate texture such as tofu, makes it possible to obtain a frozen processed food having a texture close to the original texture of the processed food after thawing. The aforementioned problem is solved by providing: an agent for preparing a frozen processed food, said agent containing processed starch and isomaltodextrin; a method for producing a frozen processed food, said method being characterized in that processed starch and isomaltodextrin are incorporated into a frozen processed food; and a frozen processed food containing processed starch and isomaltodextrin.

Description

Agent for preparing frozen processed foods, frozen processed foods, and method for producing frozen processed foods

[0001] This disclosure relates to an agent for preparing frozen processed foods.

[0002] In recent years, the demand for frozen foods has been steadily increasing due to their long shelf life and ease of preparation. The variety of frozen foods is diversifying year by year, ranging from frozen fresh produce such as vegetables, fruits, other agricultural products, livestock products, and marine products, to frozen processed foods such as sausages, hamburgers, dumplings, and takoyaki. A wide variety of frozen foods are manufactured and sold for both commercial and household use.

[0003] Naturally, for frozen foods, it is important that they can be enjoyed after thawing. However, frozen foods have the challenge that their original quality is compromised during the freezing process in manufacturing and the thawing process during consumption. This is mainly thought to be due to the formation and growth of ice crystals during the freezing and thawing process. Almost all foods contain water, and this water crystallizes and gradually grows during the freezing and thawing process. As the ice crystals grow larger, they can destroy the structure of the food, causing the water retained in the food to separate and the texture to be lost. As a means of suppressing the formation and growth of ice crystals during the freezing and thawing process, for example, rapid freezing and rapid thawing techniques that quickly pass through the temperature range where ice crystals tend to grow large (-1°C to -5°C) are known. However, since thawing frozen foods is often done in ordinary households, it is desirable that they can be enjoyed even when thawed naturally or in the refrigerator in ordinary households without knowledge of rapid thawing techniques.

[0004] Modified starch is a food material used in the preparation of various processed foods including frozen processed foods (for example, Non-Patent Document 1, etc.). In processed foods produced by adding modified starch, it is inferred that modified starch suppresses the formation and growth of ice crystals by trapping free water contained in the processed food, thereby imparting freezing and thawing resistance to the processed food. However, modified starch has unique viscosity and also has the property of gelatinizing when heated. Therefore, depending on the type of frozen food to which it is added, the resulting frozen food has a strongly perceived texture derived from modified starch.

[0005] Among various processed foods, tofu is one of the processed foods that are considered most difficult to produce as frozen processed foods. Tofu is a gel-like processed food composed of soybean protein, bittern and / or a coagulant such as glucono delta-lactone, and has a delicate texture achieved by the gel. On the other hand, tofu has a high water content of approximately 90%, and therefore ice crystals are particularly prone to form and enlarge during the freezing and thawing process. It is well known that when ordinary commercially available tofu is frozen and thawed, it undergoes syneresis and changes to a sponge-like texture (for example, Non-Patent Document 2, etc.).

[0006] As methods for imparting freezing and thawing resistance to tofu, the following are known, for example: a method of blending modified starches such as phosphorylated starch and acetate starch with a saccharide having low sweetness such as malto-oligosaccharide into soymilk (Patent Document 1); a method of adding etherified starch (for example, hydroxypropyl starch) having a degree of substitution in the range of 0.04 to 0.2, which is derived from tapioca starch, potato starch or waxy corn starch, to soymilk (Patent Document 2); a method of adding native gellan gum and modified starch to soymilk (Patent Document 3); a method of using waxy tapioca starch treated with hypochlorous acid (Patent Document 4), and the like.

[0007] However, the texture of tofu is delicate and particularly susceptible to the effects of added ingredients. The inventors have found that when modified starch is added to tofu, the texture changes significantly due to the viscosity unique to modified starch, as shown in the experimental examples described later, resulting in a texture far removed from that of tofu. Furthermore, modified starch is prone to retrogradation during the thawing process, and natural thawing or refrigerated thawing can easily cause syneresis and changes in texture. To the best of the inventors' knowledge, commercially available frozen tofu containing modified starch is invariably frozen tofu for cooking, which is thawed by heating, and there is no commercially available frozen tofu for raw consumption that is thawed naturally or refrigerated.

[0008] Japanese Patent Publication No. Hei 6-217729, Japanese Patent Publication No. Hei 9-215479, Japanese Patent Publication No. 2003-225064, Japanese Patent Publication No. 2023-151979

[0009] Tomokazu Okazaki, "Recent Trends in the Use of Starch in Frozen Foods," National Agriculture and Livestock Industries Corporation website, <URL: https: / / www.alic.go.jp / joho-d / joho08_000026.html>, Published: December 3, 2010. "Is it a Myth that Freezing Tofu Makes It Taste Bad!? 3 Recipes with a Great Sponge Texture," Yomiuri Shimbun Online, <URL: https: / / www.yomiuri.co.jp / otekomachi / 20240424-OYT8T50060 / >, Published: April 26, 2024.

[0010] The present invention has been made in view of the problems of the prior art described above, and in one aspect, aims to provide a new means to obtain a frozen processed food that, even when applied to processed foods with a delicate texture, such as tofu, has a texture close to the original texture of the processed food after thawing.

[0011] As a result of diligent research efforts to solve the above problems, the inventors have discovered that by incorporating isomaltodextrin together with modified starch into processed foods and freezing them, it is possible to obtain frozen processed foods that retain the original texture of the processed foods even after thawing, thus completing the present invention.

[0012] In other words, the present invention solves the above problem by providing an agent for preparing frozen processed foods that contains modified starch and isomaltodextrin.

[0013] Furthermore, in one aspect, the present invention solves the above problem by providing a method for producing frozen processed foods, characterized by incorporating modified starch and isomaltodextrin into the frozen processed foods.

[0014] Furthermore, in one aspect, the present invention solves the above problem by providing a frozen processed food containing modified starch and isomaltodextrin.

[0015] According to the present invention, a frozen processed food can be obtained that, after thawing, has a texture close to the original texture of the processed food.

[0016] This figure shows the results of a breaking load test of frozen tofu prepared with modified starch and isomaltodextrin, in comparison with the results obtained for ordinary tofu without modified starch or isomaltodextrin, frozen tofu obtained by freezing ordinary tofu, frozen tofu prepared with modified starch, and frozen tofu prepared with isomaltodextrin. In Figure 1, MS represents modified starch and IMD represents isomaltodextrin. This figure shows the results of a breaking load test of frozen tofu prepared with isomaltodextrin in the ratio of (A) 1 part by mass, (B) 3 parts by mass, (C) 5 parts by mass, or (D) 6 parts by mass to 3 parts by mass of modified starch. (E) shows the graphs of (A) to (D) superimposed. In Figure 2, MS represents modified starch and IMD represents isomaltodextrin. Figure 3 shows photographs of the appearance of cake donuts after frying, including a regular cake donut prepared without modified starch or isomaltodextrin, a cake donut prepared with modified starch, a cake donut prepared with isomaltodextrin, and a cake donut prepared with both modified starch and isomaltodextrin. In Figure 3, MS represents modified starch and IMD represents isomaltodextrin. Figure 4 shows the results of a breaking load test on frozen cake donuts prepared with modified starch and isomaltodextrin, in comparison with the results obtained for a regular cake donut without modified starch or isomaltodextrin, a frozen cake donut obtained by freezing the regular cake donut, and a frozen cake donut prepared with modified starch. In Figure 4, MS represents modified starch and IMD represents isomaltodextrin.

[0017] <Agent for preparing frozen processed foods> First, an agent for preparing frozen processed foods according to one aspect of the present invention will be described.

[0018] An agent for preparing frozen processed food according to one aspect of the present invention is an agent for preparing frozen processed food and is used to prepare frozen processed food.

[0019] In this disclosure, "processed food" means food that has been processed, and includes products that have been subjected to heat treatment, mixing treatment, seasoning treatment, etc., on ingredients such as vegetables, fruits, other agricultural products, livestock products, and marine products. On the other hand, fresh foods such as vegetables, fruits, other agricultural products, livestock products, and marine products, or products that have been frozen as is, are not included in the definition of "processed food" as used in this disclosure.

[0020] In this disclosure, “frozen processed food” means a processed food that has been frozen, and unless otherwise specified, it may include both foods that are eaten as is after thawing without cooking and foods that are eaten after thawing and cooking. Here, “eaten as is without cooking” basically means eaten without heating, but it also includes cases where the food is eaten after being cut into appropriate sizes and shapes with a knife or other utensil. Frozen processed food does not include processed foods that are eaten while frozen, such as frozen desserts, ice cream, or lacto ice. In other words, frozen processed food refers to a processed food that has been frozen and is eaten after thawing and / or used for cooking.

[0021] There are no particular limitations on the processed foods to which the agent relating to one aspect of the present invention can be applied; it can basically be applied to all kinds of processed foods. If we were to give examples, they could be wheat processed foods, rice processed foods, soybean processed foods, meat processed foods, seafood processed foods, egg processed foods, etc. Wheat processed foods are processed foods prepared by processing wheat-derived raw materials, and include, for example, bread, cakes, donuts, pancakes, pizza, noodles (e.g., udon, Chinese noodles, ramen, spaghetti, etc.). Rice processed foods are processed foods prepared by processing rice-derived raw materials, and include, for example, rice flour bread, rice flour cakes, rice flour donuts, rice flour pancakes, rice flour pizza, rice vermicelli, mochi, etc. Soybean processed foods are processed foods prepared by processing soybean-derived raw materials, and include, for example, tofu, tofu pudding, soybean tofu jelly, soy milk jelly, tofu sausage, tofu hamburger, tofu meatballs, fried tofu, ganmodoki, etc. Meat products are processed foods made from raw materials derived from livestock such as beef, pork, lamb, and chicken. Examples include sausages, wieners, hamburgers, meatballs, meat dumplings, shumai, gyoza, minced meat cutlets, and steamed buns. Seafood products are processed foods made from raw materials such as fish, shellfish, shrimp, crab, octopus, and squid. Examples include kamaboko, chikuwa, hanpen, and satsuma-age. Egg products are processed foods made from raw materials derived from eggs. Examples include chawanmushi, pudding, tamagoyaki, and omelets. These processed foods often contain protein and / or starch, and are prepared by mixing the raw materials and then heating them. During the heating process, protein and / or starch undergo physical property changes such as gelation, denaturation, and gelatinization, which are known to impart specific textures such as elasticity, hardness, stickiness, and softness to the food. As shown in the experimental examples described later, by using modified starch and isomaltodextrin in combination, the textures of various processed foods, each with its own unique texture produced by heating, can be maintained even after freezing and thawing. It should be noted that the above examples are merely examples of processed foods to which the agent relating to one aspect of the present invention may be applied, and do not preclude the application of the agent relating to one aspect of the present invention to other processed foods.

[0022] As described above, the processed food to which the agent relating to one aspect of the present invention is applied can be basically any type, but in one preferred embodiment, it is preferable that the processed food has a gel-like texture. In other words, in one preferred embodiment, the frozen processed food to which the agent relating to one aspect of the present invention may be applied is preferably a frozen processed food that has a gel-like texture when thawed. A gel-like texture means a texture similar to that of a gel, and is achieved by gel components contained in the processed food. That is, a processed food having a gel-like texture may be, for example, a processed food containing gel-like components, or a gel-like processed food. Specific examples of such processed foods include, but are not limited to, tofu, tofu pudding, soy milk pudding, tofu jelly, soy milk jelly, tofu sausage, tofu hamburger, tofu meatballs, almond tofu, chawanmushi, pudding, tamagoyaki, omelet, agar, konjac, bavarian cream, tapioca, jelly, sausage, wiener, hamburger, meatballs, meatballs, shumai, gyoza, minced meat cutlet, steamed bun, kamaboko, chikuwa, hanpen, satsuma-age, etc. Gels have a high water content, and therefore, during the freezing and thawing process, ice crystals are formed and enlarge, making them particularly susceptible to loss of texture. According to one aspect of the present invention, as shown in the experimental examples described later, even in the case of gel-like processed foods with particularly delicate textures, such as tofu, or processed foods containing gel-like components derived from livestock, such as hamburgers, it is possible to obtain frozen processed foods that retain their original texture.

[0023] The agent according to one aspect of the present invention can be applied to processed foods that have a gel-like texture, and is particularly suitable for use in gel-like processed foods having a delicate texture. For example, in one preferred embodiment, a gel-like processed food to which the agent according to one aspect of the present invention can be applied may be a processed food to which the breaking load when a cylindrical plunger with a diameter of 16 mm is pressed against its surface at a speed of 1 mm / sec is in the range of 0.5 to 2.0 N, preferably in the range of 0.6 to 1.8 N, more preferably in the range of 0.8 to 1.5 N, and even more preferably in the range of 0.9 to 1.2 N. A gel-like processed food exhibiting such a breaking load is a processed food that has a particularly delicate texture among processed foods that have a gel-like texture, and may be, for example, tofu, tofu pudding, soy milk pudding, tofu jelly, soy milk jelly, almond tofu, chawanmushi, pudding, bavarian cream, jelly, etc.

[0024] In one preferred embodiment, the processed food to which the agent according to one aspect of the present invention can be applied may be tofu. Tofu is a gel-like processed food composed of soy protein and a coagulant such as nigari and / or glucono delta-lactone, and has a delicate texture achieved by the gel. On the other hand, because the water content of tofu is very high, about 90%, ice crystals tend to form and grow during the freezing and thawing process, and its texture is easily lost. To the best of the inventors' knowledge, there is no known frozen tofu that can be thawed by, for example, refrigeration without heating, and that retains the original texture of tofu after thawing. In contrast, with the agent according to one aspect of the present invention, even when applied to processed foods with a particularly delicate texture, such as tofu, a frozen processed food (i.e., frozen tofu) that retains its original texture can be obtained.

[0025] However, the processed foods to which the agent relating to one aspect of the present invention can be applied are not limited to those mentioned above. For example, it may be applied to udon, soba, pasta, ramen (Chinese noodles), champon, chilled Chinese noodles, fried rice, pilaf, doria, Tenshinhan, onigiri, pizza, gyudon, okonomiyaki, takoyaki, imagawayaki, taiyaki, bread, donuts, etc. As shown in the experimental examples described later, with the agent relating to one aspect of the present invention, even processed foods containing starch-derived gel-like components (gelatinized starch), such as donuts and Chinese noodles, can be frozen processed foods that retain their original texture. Furthermore, processed foods to which the agent relating to one aspect of the present invention can be applied may also be part of frozen prepared foods, which are pre-prepared or cooked prepared foods that have been frozen.

[0026] An agent relating to one aspect of the present invention contains modified starch as its active ingredient.

[0027] There are no particular restrictions on the modified starch that can be used in the agent according to one aspect of the present invention, and an appropriate modified starch can be used depending on the processed food being targeted. Examples of modified starches that can be used in the agent according to one aspect of the present invention include, but are not limited to, acetylated adipic acid crosslinked starch, acetylated phosphate crosslinked starch, acetylated oxidized starch, sodium octenyl succinate starch, acetylated starch (acetylated starch), oxidized starch, hydroxypropyl starch, hydroxypropyl phosphate crosslinked starch, phosphate monoesterified phosphate crosslinked starch, phosphorylated starch, phosphate crosslinked starch, and sodium starch glycolate. Furthermore, the modified starch that can be used in the agent according to one aspect of the present invention may be one type or a combination of two or more types.

[0028] There are no particular restrictions on the origin of the starch used as the raw material for modified starch, but it may be starch derived from potatoes, tapioca, corn, waxy corn, peas, mung beans, wheat, rice, sweet potatoes, or sago palm. Modified starch can be produced by heat treatment, acid treatment, alkali treatment, chemical treatment, etc., of the starch obtained from these raw materials.

[0029] As described above, there are no particular restrictions on the modified starch that can be used in the agent relating to one aspect of the present invention, but in one preferred embodiment, it may be hydroxypropyl starch. Hydroxypropyl starch is a starch that has been hydroxypropylated, and is typically a modified starch obtained by etherifying starch with propylene oxide. Hydroxypropyl starch has excellent aging stability in the freezing and thawing process and can be suitably used in the production of frozen processed foods. For example, as shown in the experimental examples described later, by combining hydroxypropyl starch and isomaltodextrin, frozen tofu with an excellent texture even after thawing can be obtained.

[0030] On the other hand, an agent relating to one aspect of the present invention contains isomaltodextrin as its active ingredient.

[0031] Isomaltodextrin is a highly branched α-glucan (branched α-glucan) that has an abundance of α-1,6 linkage branching structures compared to ordinary dextrin obtained by hydrolyzing starch. Isomaltodextrin is a safe food ingredient that received GRAS (Generally Recognized As Safe) certification from the U.S. Food and Drug Administration on June 6, 2016, and is widely used, for example, as a water-soluble dietary fiber material.

[0032] Isomaltodextrin is typically produced by reacting a starchy substance (e.g., starch) with α-glucosyltransferase and, if necessary, amylase and / or starch debranching enzymes. α-glucosyltransferase is an enzyme that introduces a branched structure with a glucose polymerization degree of 1 or higher, linked via an α-1,6 bond, to at least the non-reducing glucose residue of a linear glucan with a glucose polymerization degree of 3 or higher, linked via an α-1,4 bond. For example, it may be the α-glucosyltransferase described in International Publication No. WO2008 / 136331, or more specifically, the α-glucosyltransferase derived from Paenibacillus alginoleticus (formerly Bacillus circulans) PP710 strain (FERM BP-10771), or the α-glucosyltransferase derived from Arthrobacter globiformis PP349 strain (FERM BP-10770). On the other hand, amylase and / or starch debranching enzymes may be, for example, amylases such as liquefied α-amylase (EC 3.2.1.1), saccharifying α-amylase (EC 3.2.1.1), maltotetraose-producing amylase (EC 3.2.1.60), maltohexaose-producing amylase (EC 3.2.1.98), or isoamylase (EC 3.2.1.68) or pullulanase (EC 3.2.1.41). Methods for producing isomaltodextrin using these enzymes are described, for example, in International Publication No. WO2008 / 136331. Furthermore, in one embodiment, an enzyme-treated product obtained by treating the isomaltodextrin produced as described above with an enzyme such as amyloglucosidase (glucoamylase), a fraction obtained by fractionation using size exclusion chromatography, or a reduced product obtained by reducing the glucose residue at the reducing end by hydrogenation, may be used.

[0033] The isomaltodextrin produced as described above is typically a branched α-glucan mixture having the following characteristics: (A) it contains glucose as a constituent sugar; (B) it has a branched structure with a degree of polymerization of 1 or more, linked via bonds other than α-1,4 bonds to at least the non-reducing glucose residue of a linear glucan with a degree of polymerization of 3 or more of glucose linked via α-1,4 bonds; and (C) it is produced by digestion with isomaltodextranase.

[0034] "Non-reducing end glucose residue" refers to a glucose residue located at the non-reducing end of a glucan chain (linear glucan) linked via α-1,4 bonds, and "bonds other than α-1,4 bonds" refers to bonds other than α-1,4 bonds, such as α-1,2 bonds, α-1,3 bonds, and α-1,6 bonds, preferably α-1,6 bonds.

[0035] "Isomaltodextranase digestion" means hydrolyzing isomaltodextrin by acting on it with isomaltodextranase. Isomaltodextranase is an enzyme assigned enzyme number (EC) 3.2.1.94, and is preferably isomaltodextranase derived from Arthrobacter globiformis (G. Okada et al., Agricultural and Biological Chemistry, 1988, Volume 52, Issue 2, Page 495-501). Isomaltodextranase is an enzyme that hydrolyzes isomaltodextrin regardless of the α-1,2, α-1,3, α-1,4, and α-1,6 linkages adjacent to the reducing end of the isomaltose structure.

[0036] "Isomaltose is produced by isomaltodextranase digestion" means that when isomaltodextrin is treated with isomaltodextranase and hydrolyzed, isomaltose is produced. For example, isomaltose may be present in the digest (hereinafter sometimes simply referred to as "digest") produced when isomaltodextrin is treated with isomaltodextranase. The amount of isomaltose per unit of solid matter in the digest produced by isomaltodextranase digestion reflects the amount of isomaltose structures hydrolyzed by isomaltodextranase in the branched α-glucan structure contained in isomaltodextrin, that is, the amount of α-1,6 bonds. In this way, the structure of branched α-glucan can be characterized by an enzymatic method using isomaltodextranase.

[0037] There are no particular restrictions on the isomaltose content per unit of solids of the digest produced by isomaltodextranase digestion, but it is usually 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more and 70% by mass or less, even more preferably 20% by mass or more and 60% by mass or less, even more preferably 20% by mass or more and 50% by mass or less, and even more preferably 25% by mass or more and 50% by mass or less.

[0038] Furthermore, a branched α-glucan mixture produced by reacting a starch with an α-glucosyltransferase and an amylase and / or starch debranching enzyme may, in one preferred embodiment, further have the following characteristics: the ratio of α-1,4-linked glucose residues to α-1,6-linked glucose residues is in the range of 1:0.6 to 1:4 (characteristic (D)); the sum of α-1,4-linked glucose residues and α-1,6-linked glucose residues accounts for 60% or more of the total glucose residues (characteristic (E)); α-1,3-linked glucose residues account for 0.5% or more but less than 10% of the total glucose residues (characteristic (F)); and / or α-1,3,6-linked glucose residues account for 0.5% or more of the total glucose residues (characteristic (G)). These characteristics can be determined by methylation analysis and characterize the structure of the branched α-glucan by the linkage pattern of glucose residues.

[0039] "Methylation analysis" is a method widely used by those skilled in the art to determine the bonding pattern of monosaccharides that constitute polysaccharides or oligosaccharides. Methylation analysis is described, for example, by Ciucanu et al. (I. Ciucanu and F. Kerek, Carbohydrate Research 1984, Volume 131, Issue 2, Pages 209-217). Specifically, for example, first, all free hydroxyl groups in the glucose residues constituting the glucan are methylated, and then the completely methylated glucan is hydrolyzed. Next, the methylated glucose obtained by hydrolysis is reduced to methylated glucitol to remove the anomeric form, and then the free hydroxyl groups in this methylated glucitol are acetylated to obtain partially methylated glucitol acetate (hereinafter sometimes simply referred to as "partially methylated product"). Based on the chromatogram obtained by subjecting the obtained partial methylates to gas chromatography analysis, the proportion of various partial methylates derived from glucose residues with different binding modes in the glucan can be expressed as the percentage of peak area of ​​each partial methylate in the gas chromatogram relative to the total peak area of ​​all partial methylates. Based on this, the relative abundance of glucose residues with different binding modes in the glucan, i.e., the relative abundance of each glycosidic bond, can be determined. The "ratio" for partial methylates refers to the "ratio" of peak areas in the gas chromatogram, and the "%" for partial methylates refers to the "area %" in the gas chromatogram.

[0040] In other words, "the ratio of α-1,4-linked glucose residues to α-1,6-linked glucose residues is within the range of 1:0.6 to 1:4" may mean that, in the methylation analysis of isomaltodextrin, the ratio of 2,3,6-trimethyl-1,4,5-triacetylglucitol to 2,3,4-trimethyl-1,5,6-triacetylglucitol is within the range of 1:0.6 to 1:4. This is because "α-1,4-linked glucose residues" are detected as 2,3,6-trimethyl-1,4,5-triacetylglucitol in the methylation analysis, and "α-1,6-linked glucose residues" are detected as 2,3,4-trimethyl-1,5,6-triacetylglucitol in the methylation analysis.

[0041] Similarly, "the sum of α-1,4-linked glucose residues and α-1,6-linked glucose residues accounts for 55% or more of the total glucose residues" may mean, in the methylation analysis of isomaltodextrin, that the sum of 2,3,6-trimethyl-1,4,5-triacetylglucitol and 2,3,4-trimethyl-1,5,6-triacetylglucitol accounts for 60% or more of the partially methylated glucitol acetate. Also, "α-1,3-linked glucose residues are between 0.5% and less than 10% of the total glucose residues" may mean, in the methylation analysis of isomaltodextrin, that 2,4,6-trimethyl-1,3,5-triacetylglucitol is in the range of 0.5% or more and less than 10% of the partially methylated glucitol acetate. Furthermore, the statement "α-1,3,6-linked glucose residues constitute 0.5% or more of the total glucose residues" may mean that 2,4-dimethyl-1,3,5,6-tetraacetylglucitol accounts for 0.5% or more of the partially methylated glucitol acetate.

[0042] Typically, starch does not have glucose residues bonded only at positions 1 and 6, and α-1,4-bonded glucose residues account for the majority of all glucose residues. Therefore, the above characteristics can be said to represent in more detail the characteristic branching structure of suitable isomaltodextrins that can be used in the present invention.

[0043] Furthermore, in one preferred embodiment, the branched α-glucan mixture produced by allowing α-glucosyltransferase to act on starchy material together with amylase and / or starch debranching enzyme may further be characterized by having a water-soluble dietary fiber content of 40% by mass or more (Feature (H)). The water-soluble dietary fiber content indicates the content of α-glucan that is not decomposed by α-amylase and amyloglucosidase (glucoamylase), and can also be said to characterize the structure of the branched α-glucan mixture by an enzymatic method.

[0044] The water-soluble dietary fiber content preferably means the water-soluble dietary fiber content determined by high-performance liquid chromatography (enzyme-HPLC method). The enzyme-HPLC method refers to a method in which a sample is decomposed through a series of enzymatic treatments with thermostable α-amylase, protease and amyloglucosidase (glucoamylase), then proteins, organic acids and inorganic salts are removed from the obtained treatment solution using an ion exchange resin, and the resulting product is subjected to size exclusion chromatography. The peak areas of undigested glucan and glucose in the chromatogram obtained by size exclusion chromatography are determined, and the water-soluble dietary fiber content of the sample is calculated based on each peak area and the glucose content in the sample solution that has been separately determined in advance by the glucose oxidase method according to a conventional method. The enzyme-HPLC method is described, for example, in Item 8 "Dietary Fiber" of the Nutrition Labeling Standards "Analytical Methods for Nutritional Components, etc. (methods listed in the third column of Appendix Table 1 of the Nutrition Labeling Standards)" of Ministry of Health and Welfare Notification No. 146, May 1996.

[0045] Furthermore, the branched α-glucan mixture produced by allowing α-glucosyltransferase to act on starchy material together with amylase and / or starch debranching enzyme usually has a glucose polymerization degree of 6 to 430 (Feature (I)), and the value obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn) (Mw / Mn) is usually 20 or less (Feature (J)). Methods for measuring the weight average molecular weight (Mw) and number average molecular weight (Mn) are well known to those skilled in the art, and they can be determined, for example, using size exclusion chromatography or the like. Note that the average degree of glucose polymerization can be obtained by subtracting 18 from the weight average molecular weight (Mw) and dividing the result by 162.

[0046] The isomaltodextrin that can be used in the present invention is as described above, but a suitable specific example of isomaltodextrin is the isomaltodextrin manufactured and sold by Nagase Vita Co., Ltd. (product name: Fiberixa®). The isomaltodextrin in question is a branched α-glucan mixture obtained by reacting a starch raw material such as corn starch with α-glucosyltransferase and α-amylase derived from Paenibacillus alginoleticus (formerly Bacillus circulans) PP710 strain, and through a process similar to that of a general enzyme syrup production method (starch liquefaction, enzymatic saccharification, decolorization, filtration, desalting, deodorization, and concentration) and a spray drying process. It satisfies all of the above characteristics (A) to (J), and the isomaltose content per digest produced by isomaltodextranase digestion is 25% by mass or more and 50% by mass or less.

[0047] There are no particular restrictions on the mixing ratio of modified starch and isomaltodextrin in the agent according to one aspect of the present invention. For example, it may be in the range of 1:0.1 to 1:10 by mass ratio. However, from the viewpoint of obtaining a frozen processed food with a particularly desirable texture, the lower limit of the amount of isomaltodextrin to modified starch (1) is preferably 0.33 or more, more preferably 0.5 or more, and even more preferably 1 or more. On the other hand, the upper limit of the amount of isomaltodextrin to modified starch (1) is preferably 10 or less, more preferably 5 or less, and even more preferably 3.33 or less. Therefore, the mixing ratio of modified starch to isomaltodextrin is preferably, for example, 1:0.33 to 1:10, 1:0.5 to 1:10, 1:0.33 to 1:5, 1:0.5 to 1:5, 1:0.33 to 1:3.33, and particularly preferably 1:1 to 1:3.33, but is not limited to these. In this specification, for example, when "A to B" is used to indicate a numerical range, it means a numerical range that includes the numbers at both ends (A and B) (i.e., "A or more and B or less").

[0048] As described above, the agent according to one aspect of the present invention is characterized by further containing isomaltodextrin in addition to modified starch. Modified starch is used in the production of various frozen processed foods. For example, in sauces, hydroxypropyl phosphate crosslinked starch, acetylated adipic acid crosslinked starch, etc.; in kneaded products such as kamaboko, acetic acid starch (acetylated starch), etc.; in egg products, konjac, tofu and the like, modified starch such as hydroxypropyl starch has been used (for example, Non-Patent Document 1, etc.). However, since modified starch has a unique viscosity, the texture of processed foods changes when modified starch is added. In addition, modified starch retrogrades particularly during the thawing process of frozen processed foods, which changes the quality of the processed food after thawing. Therefore, most conventional frozen processed foods containing modified starch require rapid thawing treatment such as heating thawing, and even after rapid thawing treatment, the food has a sticky texture peculiar to modified starch. In contrast, according to the findings discovered by the present inventors, when an agent according to one aspect of the present invention, which further contains isomaltodextrin in addition to modified starch, is added to a processed food and the food is frozen, a frozen processed food retaining the original texture of the processed food can be obtained even after thawing. Furthermore, even if the frozen processed food is thawed by a slower thawing treatment such as refrigerated thawing without requiring rapid thawing treatment such as heating thawing as an essential step, a frozen processed food having a favorable texture close to the original texture of the corresponding unfrozen processed food can be obtained. Therefore, the agent according to one aspect of the present invention can be suitably used for producing frozen processed foods.

[0049] As long as the agent according to one aspect of the present invention is an agent for producing frozen processed foods, there are no particular restrictions on its specific application. In a preferred embodiment, the agent can be used for imparting freeze-thaw resistance to processed foods. That is, in a preferred embodiment, the agent according to one aspect of the present invention can be a freeze-thaw resistance imparting agent for processed foods. In addition, according to one aspect, the present invention also provides a method for imparting freeze-thaw resistance to a processed food, characterized by comprising allowing the processed food to contain modified starch and isomaltodextrin.

[0050] In this disclosure, "freezing and thawing tolerance" refers to a property of processed food, meaning that the quality of the processed food is maintained after freezing and thawing, just as it was before freezing and thawing. Maintaining the quality of the processed food before freezing and thawing may mean, for example, that the quality of the processed food before freezing and thawing is maintained, preferably without containing the agent relating to one aspect of the present invention, and maintaining the quality of the processed food before freezing and thawing may mean that the quality of the processed food before freezing and thawing is maintained, for example, that the quality of the processed food before freezing and thawing is maintained, except that the agent relating to one aspect of the present invention is not used. In this specification, "freezing and thawing" means freezing and thawing, unless otherwise specified.

[0051] "Imparting" cold-thaw tolerance means giving processed foods cold-thaw tolerance and / or improving the cold-thaw tolerance of food. In other words, imparting cold-thaw tolerance may mean that, by using a cold-thaw tolerance imparting agent, the quality of the processed food after cold-thawing approaches the quality of the processed food before cold-thawing, compared to when the cold-thaw tolerance imparting agent is not used.

[0052] The "quality" of food maintained by the cold-thaw resistance that can be imparted by an agent relating to one aspect of the present invention is preferably the texture of processed food. The texture of processed food can be evaluated by appropriate methods, for example, by using a creep meter, as shown in the experimental examples described later, or by sensory evaluation by trained panelists. When evaluating texture using a creep meter, for example, a plunger of an appropriate shape may be pressed against the surface of the processed food to be evaluated, and the texture may be evaluated based on the magnitude of the load at which the processed food breaks (i.e., the breaking load) and / or the load-strain curve that represents the relationship between the load and strain obtained in this process. Regarding the method of evaluating texture using a creep meter, for example, it is also described in the experimental examples described later.

[0053] The agent according to one aspect of the present invention can be used at an appropriate stage in the process of manufacturing frozen processed foods. Basically, a processed food containing the agent according to one aspect of the present invention is prepared and the processed food is frozen. There are no particular restrictions on the specific method of use, however, for example, the agent according to one aspect of the present invention may be added to the raw materials and / or intermediates of the processed food during the process of manufacturing the processed food and mixed. The modified starch and isomaltodextrin may be added at the same time or separately.

[0054] There are no particular restrictions on the content of the agent relating to one aspect of the present invention in frozen processed foods. The total of modified starch and isomaltodextrin may be, for example, 1% by mass or more. However, from the viewpoint of obtaining a frozen processed food with a preferred texture that is closer to the texture of the original processed food, it is preferably 3.7% by mass or more, more preferably in the range of 3.7 to 11.2% by mass, even more preferably in the range of 5.5 to 11.2% by mass, and still more preferably in the range of 7.2 to 11.2% by mass. However, the content of the agent relating to one aspect of the present invention is not limited to the above and can be appropriately selected depending on the type of frozen processed food, etc.

[0055] An agent relating to one aspect of the present invention may be in the form of a composition containing modified starch and isomaltodextrin. Such a composition may contain other components in addition to modified starch and isomaltodextrin, and such components include, but are not limited to, antioxidants, acidulants, pH adjusters, preservatives, colorants, color fixatives, emulsifiers, thickeners, stabilizers, gelling agents, gelling agents, seasonings, solvents, salts, sweeteners, etc. Those skilled in the art may use any component used in the food industry depending on the type of frozen processed food, etc.

[0056] The form of the agent and / or composition relating to one aspect of the present invention is not particularly limited, and may be, for example, solid, semi-solid, or liquid. The solid form may be, for example, powder, granules, or tablets, but is not limited to these. The semi-solid form may be, for example, gel or cream, but is not limited to these. The liquid form may be, for example, aqueous solution, but is not limited to these. Furthermore, the agent and / or composition relating to one aspect of the present invention may be in the form of a concentrate that is dissolved in a suitable solvent or diluted in a suitable solvent before use. It may also be in the form of a pre-prepared formulation that can be used as is, or in the form of a formulation that is prepared at the time of use.

[0057] In one preferred embodiment, a composition containing an agent relating to one aspect of the present invention may be provided in the form of a premix powder containing wheat flour, modified starch, and isomaltodextrin. There are no particular restrictions on the content of modified starch and isomaltodextrin in such a premix powder, but the content may be, for example, 1 to 20% by mass, and preferably 5 to 15% by mass. The wheat flour may be basically any type, including strong flour, semi-strong flour, and weak flour. Rice flour may also be included in place of all or part of the wheat flour. The premix powder may be, for example, a premix powder for bakery foods such as bread, pizza, donuts, and pancakes, or a premix powder for noodle foods such as udon, Chinese noodles, and pasta (spaghetti).

[0058] The premix powder may further contain appropriate ingredients such as sugars, fats and oils, skim milk powder, eggs, and leavening agents. Sugars may be, but are not limited to, monosaccharides (e.g., glucose, xylose, fructose), disaccharides (e.g., sucrose, lactose, maltose, trehalose), sugar alcohols (e.g., sorbitol, mannitol), oligosaccharides (e.g., maltotriose), and polysaccharides (e.g., dextrin). Fats and oils may be, but are not limited to, butter, margarine, shortening, etc. Leavening agents may be, but are not limited to, baking powder.

[0059] <Method for Manufacturing Frozen Processed Foods> In one aspect, the present invention also provides a method for manufacturing frozen processed foods. The method for manufacturing frozen processed foods according to one aspect of the present invention is characterized by containing modified starch and isomaltodextrin in the frozen processed food.

[0060] There are no particular restrictions on the specific method for incorporating modified starch and isomaltodextrin into frozen processed foods. For example, one could incorporate modified starch and isomaltodextrin into a processed food and then freeze the processed food containing modified starch and isomaltodextrin. That is, a method for producing frozen processed foods according to one aspect of the present invention may include the steps of incorporating modified starch and isomaltodextrin into a processed food and freezing the processed food containing modified starch and isomaltodextrin.

[0061] There are no particular restrictions on the specific method for incorporating modified starch and isomaltodextrin into processed foods. For example, the processed food may be prepared by adding modified starch and isomaltodextrin to the raw materials and / or intermediates. That is, in one preferred embodiment, a manufacturing method according to one aspect of the present invention may include a step of preparing a processed food containing modified starch and isomaltodextrin, preferably a step of adding modified starch and isomaltodextrin to the raw materials and / or intermediates to prepare a processed food containing modified starch and isomaltodextrin. The modified starch and isomaltodextrin may be added at the same time, or they may be added at different times.

[0062] In one preferred embodiment, a manufacturing method according to one aspect of the present invention may include the step of adding and mixing modified starch and isomaltodextrin to the raw materials and / or intermediates of a processed food, and then heating the resulting mixture. In many foods, the heating process is an important step that affects the texture. For example, structural changes inside the food, such as gel formation, protein denaturation, and starch gelatinization, are likely to occur during the heating process, and these create textures such as elasticity, hardness, stickiness, and softness. As shown in the experimental examples described later, by using modified starch and isomaltodextrin in combination, the textures of various processed foods that have unique textures created by heating can be maintained even after freezing and thawing.

[0063] To explain with a specific example, if the processed food is tofu, modified starch, isomaltodextrin, and a coagulant are added to soy milk, which is the raw material for tofu, mixed, and the resulting mixture is placed in a predetermined mold and heated to obtain tofu containing modified starch and isomaltodextrin. There are no particular restrictions on the coagulant used when preparing tofu, but examples include nigari (magnesium chloride), magnesium chloride, glucono delta-lactone, and / or mixtures thereof.

[0064] There are no particular restrictions on the specific method of freezing processed foods containing modified starch and isomaltodextrin, but rapid freezing is preferable from the viewpoint of preventing ice crystal formation and enlargement, and thus preserving the texture. Here, rapid freezing means a freezing method in which the core temperature of the object to be frozen (in this case, the processed food) passes through the temperature range of -1°C to -5°C, which is the maximum ice crystal formation temperature range, within 30 minutes. There are no particular restrictions on the specific means of rapid freezing, and those skilled in the art can adopt an appropriate rapid freezing method, but for example, rapid freezing methods such as the air blast method, which involves blowing cold air onto the object; the brine method, which involves immersing the object in alcohol brine and freezing it; the liquefied gas method, which uses liquid nitrogen or liquid carbon dioxide; and the contact method, which involves sandwiching the object between cooled metal plates and freezing it, can be used.

[0065] By incorporating modified starch and isomaltodextrin into processed foods, the processed foods are given resistance to freezing and thawing. Frozen processed foods obtained by freezing processed foods containing modified starch and isomaltodextrin may have a desirable texture that is close to the original texture of the processed food even after thawing.

[0066] <Frozen Processed Foods> In one aspect, the present invention also provides frozen processed foods containing modified starch and isomaltodextrin.

[0067] According to the findings of the present inventors, by including modified starch and isomaltodextrin in processed foods, the processed foods are given resistance to freezing and thawing, and frozen processed foods can be obtained that have a desirable texture close to the original texture of the processed food even after freezing and thawing. In other words, a frozen processed food according to one aspect of the present invention that contains modified starch and isomaltodextrin is a frozen processed food that has a desirable texture close to the original texture of the processed food even after thawing.

[0068] A frozen processed food according to one aspect of the present invention only needs to contain modified starch and isomaltodextrin, and is not particularly limited in other characteristics. In other words, a frozen processed food according to one aspect of the present invention can be basically any type of frozen processed food as long as it contains modified starch and isomaltodextrin. The preferred types and forms of frozen processed foods, the modified starch and isomaltodextrin that can be used in a frozen processed food according to one aspect of the present invention, and the blending ratio and content of modified starch and isomaltodextrin in a frozen processed food according to one aspect of the present invention have already been described, so a detailed explanation is omitted here.

[0069] A frozen processed food according to one aspect of the present invention is thawed by an appropriate method before consumption. There are no particular restrictions on the method of thawing the frozen processed food, but for example, it may be thawed by refrigeration, or it may be thawed by leaving it in a refrigerator that has been heated to a predetermined temperature such as 8°C or below, preferably 5°C or below, more preferably 4°C or below. However, the method of thawing the frozen processed food is not limited to refrigeration, and for example, it may be thawed naturally, thawed under running water, or thawed by heating. Natural thawing may be done at room temperature. Room temperature is typically 25°C, but for example, it may be 10°C to 40°C, 15°C to 35°C, or 20°C to 30°C. On the other hand, there are no particular restrictions on the specific method of thawing by heating, and it may be heated in a water bath in boiling water or lukewarm water at about 30 to 50°C, heated in a microwave oven, or cooked in a frying pan or the like. For example, if the frozen processed food according to one aspect of the present invention is tofu (frozen tofu), it may be used directly in cooking various tofu dishes such as boiled tofu, simmered dishes, mapo tofu, tofu soup, tofu miso soup, and tofu hot pot, and may be thawed by heating during the cooking process.

[0070] <Experimental Examples> The present invention will be described in detail below based on experimental examples, but the present invention is not limited in any way to these experimental examples.

[0071] Experiment 1. Texture Test of Frozen Tofu In Experiment 1, tofu, one of the foods whose texture is most easily affected by freezing and thawing processes and the addition of modified starch, was used as an example. Specifically, first, in the quantities shown in Table 1, a portion of unadjusted soy milk (product name "One Superior Soy Milk"; manufactured by Marusanai Co., Ltd.) was mixed with hydroxypropylated starch derived from tapioca (product name "Ikaruga 100"; manufactured by Oji Corn Starch Co., Ltd.) and isomaltodextrin (product name "Fiberixa" (registered trademark); manufactured by Nagase Vita Co., Ltd.) as modified starches. The remaining unadjusted soy milk was added to this mixture and mixed. Then, a tofu coagulant (product name "Tatsujin No. 6"; manufactured by Riken Vitamin Co., Ltd.) dissolved in water was added to the resulting mixture and mixed further. The resulting mixture was filled into molds of a predetermined shape (shallow jelly cups) in 40g portions, sealed with a seal, and heated at 90°C for 1 hour. For control sample 1-1, the obtained tofu was refrigerated in a refrigerator at 4°C and used in the tests described later. For control sample 1-2 and test samples 1-1 to 1-3, the obtained tofu was rapidly frozen at -40°C for 30 minutes to obtain frozen tofu. The resulting frozen tofu was stored frozen, thawed in a refrigerator at 4°C, and then used in the tests described later.

[0072]

[0073] The breaking load of the obtained samples was measured using a creep meter (model number "RE2-33005C"; manufactured by Yamaden Co., Ltd.). Specifically, the sample, with its seal removed, was placed in its cup on the creep meter stage, and a cylindrical plunger was pushed in from the exposed top surface of the tofu to cause a through-break. The load and strain during this process were recorded. The measurement conditions for the creep meter were as follows: Plunger: No. 3 (φ16 mm cylinder) Measurement speed: 1 mm / sec Measured strain: 99% In this experiment, a measured strain of 99% means that the tofu, with a thickness of approximately 15 mm as the reference, was broken through to 14.85 mm. The obtained results are shown in Figure 1.

[0074] As shown in Figure 1, the breaking load of control sample 1-1, which was ordinary tofu that did not contain modified starch or isomaltodextrin and was not frozen but stored under refrigeration, was 1.09 N. In contrast, control sample 1-2, which was obtained by freezing and thawing ordinary tofu that did not contain modified starch or isomaltodextrin, deformed at a load smaller than the breaking load measured for control sample 1-1 and did not show a clear breaking load. This result means that in ordinary tofu that does not contain modified starch or isomaltodextrin, the original texture of the tofu is impaired by the freezing and thawing process.

[0075] Furthermore, for test sample 1-1, which was obtained by freezing and thawing tofu containing only isomaltodextrin without modified starch, the results were almost the same as those for control sample 1-2. It deformed at a much smaller load than the breaking load observed for control sample 1-1 and did not show a clear breaking load. This result indicates that the texture of tofu containing only isomaltodextrin after freezing and thawing is far removed from the original texture of tofu.

[0076] In contrast to test sample 1-1, the breaking load of test sample 2, obtained by freezing and thawing tofu containing modified starch without isomaltodextrin (i.e., tofu containing only modified starch), was 1.61 N, which was significantly larger than the breaking load of control sample 1-2. This result indicates that the addition of modified starch to tofu imparted elasticity derived from the modified starch, and it can be seen that the texture of tofu containing only modified starch after freezing and thawing is far removed from the original texture of tofu.

[0077] In contrast, the breaking load of test sample 1-3, which contained both modified starch and isomaltodextrin, was 1.16 N, which was surprisingly almost the same as the breaking load of control sample 1-1, which was regular tofu stored under refrigeration. This result indicates that by incorporating modified starch and isomaltodextrin into processed foods, it is possible to obtain frozen processed foods that retain the same texture as before freezing and thawing, even in processed foods with a very delicate texture, such as tofu.

[0078] Experiment 2. Examination of the mixing ratio of modified starch and isomaltodextrin. In the amounts shown in Table 2, a portion of unadjusted soy milk (product name "One-Step Superior Soy Milk"; manufactured by Marusanai Co., Ltd.) was mixed with tapioca-derived hydroxypropylated starch (product name "Ikaruga 100"; manufactured by Oji Corn Starch Co., Ltd.) and isomaltodextrin (product name "Fiberixa" (registered trademark); manufactured by Nagase Vita Co., Ltd.) as modified starches. The remaining unadjusted soy milk was added to this mixture and mixed. Then, a tofu coagulant (product name "Tatsujin No. 6"; manufactured by Riken Vitamin Co., Ltd.) dissolved in water was added to the resulting mixture and mixed further. 40g portions of the resulting mixture were filled into molds of a predetermined shape (shallow jelly cups), sealed, and heated at 90°C for 1 hour. For control sample 2-1, the resulting tofu was refrigerated and stored in a refrigerator at 4°C and used in the tests described later. For test samples 2-1 to 2-5, the obtained tofu was rapidly frozen at -40°C for 30 minutes to obtain frozen tofu. The resulting frozen tofu was stored frozen, thawed in a refrigerator at 4°C, and then used in the tests described later.

[0079]

[0080] The fracture load was measured in the same manner as in Experiment 1. The results obtained are shown in Figure 2.

[0081] As shown in Figure 2, the breaking loads of test samples 2-2, 2-3, 2-4, and 2-5, which were blended with isomaltodextrin in ratios of 1, 3, 5, and 10 parts by mass to 3 parts by mass of modified starch, were 1.32 N, 1.35 N, 1.16 N, and 1.13 N, respectively. All of these values ​​were close to the breaking load of control sample 2-1, which was regular tofu stored under refrigeration (1.09 N), compared to the breaking load of test sample 2-1, which contained only modified starch (1.61 N).

[0082] Next, sensory evaluations were conducted on test samples 2-1 to 2-5. In the sensory evaluations, texture was used as an evaluation criterion. Using control sample 2-1, which was regular tofu stored in the refrigerator, as the baseline, samples were evaluated as follows: "○" if the texture was the same, "△" if the texture was slightly different, and "×" if the texture was different. The sensory evaluations were conducted by five panelists who scored 80 points or higher in the five-taste identification test. The results are shown in Table 3. In Table 3, the evaluation results from each panel and the median of the evaluation results from each panel are shown as the overall evaluation.

[0083]

[0084] As shown in Table 3, the sensory evaluation results for test samples 2-2, 2-3, 2-4, and 2-5, which were blended with isomaltodextrin in ratios of 1, 3, 5, and 10 parts by mass to 3 parts by mass of modified starch, were "△", "〇", "〇", and "〇", respectively. All of test samples 2-2 to 2-5 were evaluated as having a texture similar to control sample 2-1, which is regular tofu stored under refrigeration, compared to the sensory evaluation result ("×") of test sample 2-1, which was blended with modified starch alone. In particular, the sensory evaluation results for test samples 2-3, 2-4, and 2-5, which were blended with isomaltodextrin in ratios of 3, 5, and 10 parts by mass to 3 parts by mass of modified starch, were "〇", and they were evaluated as having a texture equivalent to control sample 2-1, which is regular tofu stored under refrigeration.

[0085] The above results suggest that, even in the case of tofu, a gel-like processed food with a very delicate texture, by incorporating modified starch and isomaltodextrin, it is possible to obtain a frozen processed food that retains a texture closer to the original texture before thawing, regardless of the ratio of modified starch to isomaltodextrin. From the viewpoint of bringing the texture after thawing closer to the original texture before thawing, the ratio of modified starch to isomaltodextrin is preferably 4:1 to 1:4 (1:0.25 to 1:4), more preferably 3:1 to 3:10 (1:0.33 to 1:3.33), and even more preferably 1:1 to 3:10 (1:1 to 1:3.33).

[0086] Furthermore, the amounts of modified starch and isomaltodextrin relative to the total mass of tofu were 3.7% by mass (= 4 / 107.45) for test sample 2-2, 5.5% by mass (= 6 / 109.45) for test sample 2-3, 7.2% by mass (= 8 / 111.45) for test sample 2-4, and 11.2% by mass (= 13 / 116.45) for test sample 2-5. From this, it can be seen that by incorporating modified starch and isomaltodextrin into processed foods, it is possible to obtain frozen processed foods that retain a texture closer to the original texture before freezing and thawing, regardless of the amount of modified starch and isomaltodextrin used. However, from the viewpoint of bringing the texture after freezing and thawing closer to the original texture before freezing and thawing, the amount of modified starch and isomaltodextrin added to the total mass of the processed food is preferably 3.7% by mass or more, preferably in the range of 3.7 to 11.2% by mass, more preferably in the range of 5.5 to 11.2% by mass, and even more preferably in the range of 7.2 to 11.2% by mass.

[0087] Experiment 3. Texture Test of Frozen Cake Donuts As another example of frozen processed foods, frozen cake donuts were prepared. Specifically, cake donuts were prepared using the sugar batter method in the quantities shown in Table 4. Specifically, butter was made into a pomade-like consistency, then sugar and isomaltodextrin (product name "Fiberixa"; manufactured by Nagase Vita Co., Ltd.) were added and mixed well. Beaten eggs were added little by little and mixed further, then a mixture of strong flour (product name "Million"; manufactured by Nisshin Flour Milling Co., Ltd.), weak flour (product name "Violet"; manufactured by Nisshin Flour Milling Co., Ltd.), and oxidized starch derived from cornstarch (product name "Seiun 500"; manufactured by Oji Cornstarch Co., Ltd.) was sifted in and mixed. The resulting mixture (dough) was rolled out to a thickness of 1 cm and refrigerated for 1 hour. After chilling, the dough was cut out using a 73mm diameter ring mold, a hole was made using a 28mm diameter ring mold, and a slit was made using a 52mm diameter ring mold to form a ring shape. Then, it was fried in 170°C oil for 2 minutes on each side to obtain the cake donut.

[0088]

[0089] Figure 3 shows photographs of the cake donuts after oiling. As shown in Figure 3, the regular cake donuts prepared without any modified starch or isomaltodextrin, the cake donuts prepared with modified starch, and the cake donuts prepared with both modified starch and isomaltodextrin all maintained their donut shape (ring shape), whereas the cake donuts prepared with isomaltodextrin disintegrated during oiling.

[0090] Control sample 3-1 was stored at room temperature and used in the tests described later. On the other hand, control sample 3-2 and test samples 3-1 to 3-3 were rapidly frozen at -40°C for 1 hour to obtain frozen cake donuts. The resulting frozen cake donuts were thawed at room temperature at 25°C for 5 hours and then used in the tests described later. The ratio of modified starch to isomaltodextrin in this example is 1:10.

[0091] The breaking loads of control sample 3-1, control sample 3-2, test sample 3-2, and test sample 3-3 were measured in the same manner as in Experiment 1. As shown in Figure 3, test sample 3-1, which was prepared with isomaltodextrin, was extremely brittle, and it was determined that measuring the breaking load would be difficult, so it was excluded from the samples in this test. The results obtained are shown in Figure 4. As shown in Figure 4, the breaking load of control sample 3-1, which was a normal cake donut prepared without the addition of either modified starch or isomaltodextrin and was not frozen, was 8.9 N. In contrast, the breaking load of control sample 3-2, which was obtained by freezing and thawing a normal cake donut prepared without the addition of either modified starch or isomaltodextrin, was 7.9 N, which was lower than the breaking load of control sample 3-1. These results indicate that in regular cake donuts that do not contain either modified starch or isomaltodextrin, the original texture of the cake donut is compromised by freezing and thawing.

[0092] Furthermore, the breaking load of test sample 3-2, obtained by freezing and thawing a cake donut prepared with modified starch, was 7.2 N, which was even lower than the breaking load of control sample 3-2. This result indicates that the texture of cake donuts prepared with modified starch after freezing and thawing is far inferior to the original texture of cake donuts.

[0093] In contrast, the breaking load of test sample 3-3, which was prepared by freezing and thawing a cake donut containing both modified starch and isomaltodextrin, was 9.2 N. This value was equivalent to or slightly higher than the breaking load of control sample 3-1, which was a regular cake donut before freezing. This result indicates that by incorporating modified starch and isomaltodextrin, it is possible to obtain a frozen cake donut that retains a texture equivalent to that of a regular cake donut even after thawing.

[0094] Next, sensory evaluations were conducted on test samples 3-1 to 3-3 and control sample 3-2. In the sensory evaluations, texture was used as an evaluation item. Using control sample 3-1, which is a regular cake donut, as the baseline, a "○" was used if the texture was the same, a "△" if the texture was slightly different, and a "×" if the texture was different. The sensory evaluations were conducted by five panelists who scored 80 points or higher in the five tastes identification test. The results are shown in Table 5. In Table 5, the evaluation results from each panel and the median of the evaluation results from each panel are shown as the overall evaluation.

[0095]

[0096] As shown in Table 5, the sensory evaluation result for control sample 3-2, which was obtained by freezing and thawing a regular cake donut prepared without the addition of modified starch or isomaltodextrin, was "△", indicating that it had a slightly different texture from control sample 3-1, which was a regular cake donut. Regarding control sample 3-2, the panel commented that it had a slightly brittle texture compared to control sample 3-1.

[0097] On the other hand, the sensory evaluation result for test sample 3-1, which was prepared by freezing and thawing a cake donut containing modified starch, was "△," indicating that it had a slightly inferior and different texture compared to control sample 3-1, which was a regular cake donut. Regarding test sample 3-1, the panel commented that it had a slightly firmer texture compared to control sample 3-1.

[0098] Furthermore, the sensory evaluation result for test sample 3-2, which was obtained by freezing and thawing a cake donut prepared with isomaltodextrin, was "×", indicating that it had a different texture from control sample 3-1, which was a regular cake donut. The panel commented that test sample 3-2 had a mushy and crumbly texture.

[0099] In contrast, the sensory evaluation result for test sample 3-3, which was prepared by combining both modified starch and isomaltodextrin, was "○", and it was evaluated as having a texture equivalent to that of control sample 3-1, which is a regular cake donut.

[0100] The results shown in Figure 4 and Table 5 demonstrate that by incorporating modified starch and isomaltodextrin, frozen cake donuts can be produced that retain a texture closer to the original texture of cake donuts even after thawing. It can be seen that by combining modified starch with isomaltodextrin, processed foods that retain a texture closer to the original texture even after thawing can be obtained, not only for tofu but for a wide range of processed foods. Furthermore, it can be seen that the cold-thaw tolerance-contributing effect is exhibited even when the ratio of modified starch to isomaltodextrin is 1:10.

[0101] Experiment 4: Texture Test of Frozen Chinese Noodles As another example of frozen processed foods, frozen Chinese noodles were prepared. Specifically, in the quantities shown in Table 6, semi-strong flour (product name "Toku No. 1"; manufactured by Nisshin Flour Milling Co., Ltd.) and wheat-derived starch acetate (product name "Hakurin L"; manufactured by Glico Nutrition Foods Co., Ltd.) were mixed in powder form. Meanwhile, isomaltodextrin (product name "Fiberixa" (registered trademark); manufactured by Nagase Vita Co., Ltd.), salt, and lye water (product name "Kansui Aka"; manufactured by Oriental Yeast Industry Co., Ltd.) were dissolved in water and combined with the mixture of semi-strong flour and modified starch, and mixed for 15 minutes to obtain noodle dough. The process of compounding the obtained noodle dough to a thickness of 5 mm was repeated three times, and then it was aged at room temperature for 1 hour. It was then rolled in stages to thicknesses of 5 mm, 4 mm, 3 mm, 2 mm, and 1.5 mm, and finally cut out at a thickness of 1.5 mm using a cutting blade with a cutting blade number of 20. The cut noodles were divided into 300g portions, boiled in 3.5L of boiling water for 2 minutes, cooled in ice water, and drained to obtain Chinese noodles. Control sample 4-1 was prepared immediately before the sensory test using the above procedure. For control sample 4-2 and test samples 4-1 to 4-3, 160g portions of the obtained Chinese noodles were packed into molds, rapidly frozen at -40°C for 30 minutes, and then packaged in high-barrier type packaging bags (product name "High Barrier Kyobijin"; manufactured by Kurilon Chemicals Co., Ltd.) and stored in a freezer. These samples were thawed by boiling them in boiling water for 2 minutes while still frozen, and used in the sensory test described later. The ratio of modified starch to isomaltodextrin in this example is 1:0.5.

[0102]

[0103] In the sensory evaluation, texture was used as an evaluation criterion. Using control sample 4-1, which was regular Chinese noodles that had not been frozen after cooking, as the baseline, a "○" was used if the texture was equivalent, a "△" if the texture was slightly different, and a "×" if the texture was different. The sensory evaluation was conducted by five panelists who scored 80 points or higher on the five tastes identification test. The results are shown in Table 7. In Table 7, the evaluation results from each panel and the median of the evaluation results from each panel as the overall evaluation are shown.

[0104]

[0105] As shown in Table 7, the sensory evaluation result for control sample 4-2, which was obtained by freezing and thawing regular Chinese noodles prepared without the addition of modified starch or isomaltodextrin, was "△", indicating that it had a slightly different texture from control sample 4-1. Regarding control sample 4-2, the panel commented that it was softer compared to control sample 4-1.

[0106] On the other hand, the sensory evaluation result for test sample 4-1, which was prepared by freezing and thawing Chinese noodles containing modified starch, was "△", indicating that it had a slightly different texture from control sample 4-1. Regarding test sample 4-1, the panel commented that it was chewier but less firm compared to control sample 4-1.

[0107] Furthermore, the sensory evaluation result for test sample 4-2, which was obtained by freezing and thawing Chinese noodles prepared with isomaltodextrin, was "×", indicating a different texture from control sample 4-1. The panel commented that test sample 4-2 was soft and brittle.

[0108] In contrast, the sensory evaluation result for test sample 4-3, which was prepared by combining both modified starch and isomaltodextrin, was "○", and it was evaluated as having a texture equivalent to that of control sample 4-1. The panel commented that test sample 4-3 had the same hardness as control sample 4-1 and was easy to bite.

[0109] The results above demonstrate that by incorporating modified starch and isomaltodextrin, frozen Chinese noodles can be produced that retain a texture closer to that of original Chinese noodles even after thawing. It is clear that combining modified starch with isomaltodextrin can yield a wide range of processed foods that retain a texture closer to that of original noodles even after thawing. Furthermore, it can be seen that the cold-thaw tolerance-contributing effect is observed even when the ratio of modified starch to isomaltodextrin is 1:0.5.

[0110] Experiment 5: Texture Test of Frozen Hamburgers As another example of frozen processed foods, frozen hamburgers were prepared. Specifically, ground beef (beef:pork = 6:4) and salt were mixed in the quantities shown in Table 8 using a tabletop mixer (Kenmix) at speed "1" for 5 minutes at 3°C. Breadcrumbs and milk were mixed, and the breadcrumbs soaked in milk were added to the mixture of ground beef and salt and mixed. Meanwhile, hydroxypropylated phosphate cross-linked starch derived from tapioca (product name "Chemister SH"; manufactured by Glico Nutrition Foods Co., Ltd.), sautéed onions, isomaltodextrin (product name "Fiberixa"; manufactured by Nagase Vita Co., Ltd.), white pepper, nutmeg, and whole egg (strained) were mixed using a tabletop mixer (Kenmix) at speed "1" for 2 minutes, and the mixture was left to rest in a refrigerator at 4°C for 30 minutes. The resulting hamburger mixture was divided into 80g portions, air was removed, and the shapes were formed using a 7.2cm diameter ring mold. Seven portions were placed in each layer on a baking sheet, and the mixture was baked in a steam convection oven in combi mode, with 70% steam, 200°C oven temperature, and 1 / 2 airflow for 11 minutes to obtain the hamburgers. Control sample 5-1 was prepared immediately before the sensory test using the above procedure. For control sample 5-2 and test samples 5-1 to 5-3, the obtained hamburgers were rapidly frozen at -40°C for 30 minutes, packaged in high-barrier type packaging bags (product name "High Barrier Kyobijin"; manufactured by Kurilon Kasei Co., Ltd.), and stored in a freezer. These samples were thawed by boiling them in boiling water for 5 minutes while still frozen and packaged, and used in the sensory test described later. The ratio of modified starch to isomaltodextrin in this example is 1:5.

[0111]

[0112] In the sensory evaluation, texture was used as an evaluation criterion. Using control sample 5-1, which was a regular hamburger patty that had not been frozen after cooking, as the baseline, a "○" was used if the texture was equivalent, a "△" if the texture was slightly different, and a "×" if the texture was different. The sensory evaluation was conducted by five panelists who scored 80 points or higher on the five tastes identification test. The results are shown in Table 9. In Table 9, the evaluation results from each panel and the median of the evaluation results from each panel as the overall evaluation are shown.

[0113]

[0114] As shown in Table 9, the sensory evaluation result for control sample 5-2, which was obtained by freezing and thawing a regular hamburger patty prepared without the addition of modified starch or isomaltodextrin, was "△", indicating that it had a slightly different texture from control sample 5-1. Regarding control sample 5-2, the panel commented that it was softer compared to control sample 4-1.

[0115] On the other hand, the sensory evaluation result for test sample 5-1, which was prepared by freezing and thawing a hamburger patty containing modified starch, was "△", indicating that it had a slightly different texture from control sample 5-1. Regarding test sample 5-1, the panel commented that it was harder and more elastic compared to control sample 5-1.

[0116] Furthermore, the sensory evaluation result for test sample 5-2, which was prepared by freezing and thawing a hamburger patty containing isomaltodextrin, was "×", indicating a different texture from control sample 5-1. The panel commented that test sample 5-2 was soft and easily crumbled.

[0117] In contrast, the sensory evaluation result for test sample 5-3, which was prepared by combining both modified starch and isomaltodextrin, was "○", and it was evaluated as having a texture equivalent to that of control sample 5-1. The panel commented that test sample 5-3 was a hamburger with just the right firmness, similar to that of control sample 5-1.

[0118] The results above demonstrate that by incorporating modified starch and isomaltodextrin, frozen hamburgers can be produced that retain a texture closer to that of the original hamburger even after thawing. It is clear that combining modified starch with isomaltodextrin can yield a wide range of processed foods that retain a texture closer to that of the original even after thawing. Furthermore, it can be seen that the cold-thaw tolerance-enhancing effect is observed even when the ratio of modified starch to isomaltodextrin is 1:5.

[0119] According to the present invention, even processed foods with a delicate texture, such as tofu, can be frozen after thawing to obtain a processed food that retains a texture close to that of the original processed food. The industrial applicability of the present invention is enormous, as it enables the provision of a wider variety of delicious frozen processed foods.

Claims

1. An agent for preparing frozen processed foods, containing modified starch and isomaltodextrin.

2. The agent according to claim 1, wherein the mixing ratio of the modified starch and the isomaltodextrin is within the range of 1:0.1 to 1:

10.

3. The agent according to claim 1 or 2, wherein the frozen processed food is gel-like and / or contains a gel-like component when thawed.

4. The agent according to any one of claims 1 to 3, wherein the frozen processed food is a wheat processed food, a rice processed food, a soybean processed food, a meat processed food, a seafood processed food, and / or an egg processed food.

5. A frozen processed food containing modified starch and isomaltodextrin.

6. The frozen processed food according to claim 5, wherein the mixing ratio of the modified starch to the isomaltodextrin is in the range of 1:0.1 to 1:

10.

7. The frozen processed food according to claim 5 or 6, which is gel-like and / or contains a gel-like component when thawed.

8. A frozen processed food according to any one of claims 5 to 7, which is a wheat processed food, a rice processed food, a soybean processed food, a meat processed food, a seafood processed food, and / or an egg processed food.

9. A method for producing frozen processed food, characterized by containing modified starch and isomaltodextrin in the frozen processed food.

10. The manufacturing method according to claim 9, comprising the steps of: preparing a processed food containing modified starch and isomaltodextrin; and freezing the processed food.

11. The manufacturing method according to claim 9 or 10, wherein the ratio of the modified starch to the isomaltodextrin in the frozen processed food is within the range of 1:0.1 to 1:

10.

12. The manufacturing method according to any one of claims 9 to 11, wherein the frozen processed food is gel-like and / or contains a gel-like component when thawed.

13. The manufacturing method according to any one of claims 9 to 12, wherein the frozen processed food is a wheat processed food, a rice processed food, a soybean processed food, a meat processed food, a seafood processed food, and / or an egg processed food.

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