yogurt

Abstract

This product provides yogurt in which the separation of liquid components is suppressed when thawed after freezing. [Solution] Yogurt containing one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin.

Description

Technical Field

[0001] The present invention relates to yogurt.

Background Art

[0002] Yogurt is a food that is popular for its high nutritional value and its effect of conditioning the intestinal environment. Some attempts have been made to maintain the quality of yogurt during storage. Patent Document 1 discloses that adding cellulose to yogurt can suppress syneresis during refrigerated storage. Patent Document 2 discloses that adding tapioca starch to yogurt can impart a new texture when it undergoes freeze-thawing. Patent Document 3 discloses that a frozen dessert containing microcrystalline cellulose and konjac can suppress problems of thawing and thermal shock.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, with the growing health consciousness and increasing interest in probiotics, the demand for yogurt has been expanding. Meeting this demand requires long-term storage and long-distance transportation of yogurt, making the technology for freezing yogurt increasingly important. However, when yogurt is frozen, the water it contains crystallizes, and liquid components such as whey may separate upon thawing. These separated liquid components can negatively affect the appearance and texture of the product, potentially impairing consumer preference. The objective of this invention is to provide yogurt in which the separation of liquid components is suppressed when thawed after freezing. [Means for solving the problem]

[0005] The inventors of the present invention have found that the above-mentioned problems can be solved in yogurt containing a specific water-soluble dietary fiber, and have completed the present invention.

[0006] This disclosure includes the following forms: <1> Yogurt containing one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin. <2> Furthermore, the yogurt described in item 1 contains water-insoluble dietary fiber. <3> The aforementioned cyclic tetrasaccharide is a sugar having the structure cyclo{→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→}. Yogurt as described in item 1 or 2. <4> The amount of water-soluble dietary fiber is 1.5 to 16% by mass of the total mass of the yogurt. Yogurt as described in any one of items 1 to 3. <5> Yogurt that is unsweetened, as described in any one of items 1 to 4. <6> - The yogurt described in any one of items 1 to 5, wherein when Ag yogurt, which has been stored at 20°C for one month and then at 4°C for 15 hours, is left to stand on a 500 μm mesh sieve at 25°C for 2 hours, the amount of liquid that falls to the bottom of the sieve is Bg, and the syneresis rate shown by the following formula is 45% by mass or less. (Formula) Separation rate (%)=B / A×100 <7> A composition for improving the quality of yogurt, comprising one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin. <8> The aforementioned quality improvement is one or more selected from the group consisting of suppression of syneresis, improvement of texture, improvement of appearance, and improvement of taste. A composition for improving the quality of yogurt as described in item 7. [Effects of the Invention]

[0007] The yogurt of the present invention can suppress the separation of liquid components when thawed after freezing. [Modes for carrying out the invention]

[0008] <<Yogurt>> The yogurt of the present invention is characterized by containing one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin. The inclusion of these water-soluble dietary fibers suppresses the separation of liquid components when the yogurt is thawed after freezing.

[0009] The yogurt of the present invention may be any of the following: hard yogurt, which is solidified after fermentation; soft yogurt, which is stirred after fermentation to homogenize the whey and solids; or a drinkable type yogurt, which is stirred after fermentation to homogenize the whey and solids, and then has its viscosity adjusted to give it a drinkable fluidity.

[0010] <Water-soluble dietary fiber> Water-soluble dietary fiber suppresses the separation of liquid components when yogurt is frozen and then thawed. Water-soluble dietary fiber refers to indigestible components in food that are soluble in solvents such as water and are not digested or are difficult to digest by human digestive enzymes. Examples of water-soluble dietary fiber include indigestible carbohydrates such as cyclic tetrasaccharides, indigestible dextrin, and inulin, which may be used individually or in combination of two or more.

[0011] Generally, fermented yogurt gels due to the aggregation of proteins through isoelectric point precipitation, and water molecules are thought to exist in the spaces between the aggregated proteins. When gelled yogurt is frozen, the water molecules change into ice crystals, denaturing the aggregated proteins. As a result, the gel breaks down upon thawing, and the liquid components separate. In contrast, in the yogurt of the present invention, water-soluble dietary fiber binds to water molecules, suppressing the growth of ice crystals during freezing, thus suppressing the separation of liquid components after thawing. However, the present invention is not limited to this mechanism.

[0012] A cyclic tetrasaccharide is a molecule in which four monosaccharides are linked together in a ring. The monosaccharides that make up a cyclic tetrasaccharide are not particularly limited and include, for example, glucose, fructose, ribose, mannose, galactose, allose, talose, xylose, arabinose, psicose, and tagatose, with glucose being preferred. The linkage between monosaccharides in a cyclic tetrasaccharide is not particularly limited and includes, for example, α1,3 links, α1,4 links, and α1,6 links. Because cyclic tetrasaccharides have no off-flavors and possess a slight sweetness, they can improve the quality of yogurt without interfering with its flavor. Furthermore, since cyclic tetrasaccharides are colorless and transparent when dissolved in water, they do not impair the appearance of the yogurt.

[0013] Examples of cyclic tetrasaccharides include the following substances: A non-reducing cyclic tetrasaccharide (also known as cyclonigerosylnigerose, CNN) having the structure cyclo{→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→) · A non-reducing cyclic tetrasaccharide having the structure of cyclo{→6)-α-D-glucopyranosyl-(1→4)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→4)-α-D-glucopyranosyl-(1→} (alias: cyclomaltosyl maltose, CMM)

[0014] As the cyclic tetrasaccharide, a pure substance without impurities (such as cyclic tetrasaccharide 5 hydrate crystals) may be used, or a composition containing a cyclic tetrasaccharide may be used. Examples of the composition containing a cyclic tetrasaccharide include "Tetralin (registered trademark)" manufactured by Nagase Vita Co., Ltd. This composition is a composition in a water candy-like form containing a cyclic tetrasaccharide. In this specification, such a cyclic tetrasaccharide-containing composition in a water candy-like form is also referred to as "cyclic tetrasaccharide water candy". In addition to the cyclic tetrasaccharide, the cyclic tetrasaccharide water candy may contain branched cyclic tetrasaccharides in which one or more molecules of glucose are bonded to the cyclic tetrasaccharide, and coexisting saccharides such as glucose and maltose.

[0015] Resistant dextrin is a water-soluble dietary fiber that is difficult to be decomposed by digestive enzymes. Resistant dextrin preferably has α1→2 bonds and α1→3 bonds in addition to α1→4 bonds and α1→6 bonds as glucoside bonds. Resistant dextrin produced by the decomposition of starch can be used. The weight average molecular weight of resistant dextrin is preferably 1000 to 10000, more preferably 1500 to 6000, and even more preferably 2000 to 4000. Examples of the product names of resistant dextrin include Fibersol 2 (manufactured by Matsutani Chemical Industry Co., Ltd.), Neutrioce FB06 (Rocket Japan Co., Ltd.), Promitor 85 (Tate & Lyle Japan Co., Ltd.), etc.

[0016] Inulin is a polymer mainly composed of fructose and is a water-soluble dietary fiber that is difficult to be decomposed by digestive enzymes. The weight-average molecular weight of inulin is preferably from 1,000 to 20,000, more preferably from 2,000 to 10,000, and even more preferably from 3,000 to 8,000. Examples of the product names of inulin include Fujifurafinn FF (Fujifurafinn Co., Ltd.), Orafti GR (DKSH Japan Co., Ltd.), Inulia (Teijin Limited), etc.

[0017] The content of the water-soluble dietary fiber is preferably 8 to 50% by mass in the solid content of the yogurt, more preferably 10 to 48% by mass, even more preferably 15 to 43% by mass, even more preferably 18 to 40% by mass, and particularly preferably 23 to 35% by mass. Also, the content of the water-soluble dietary fiber is preferably 1.5 to 16% by mass in the total mass of the yogurt, more preferably 2.1 to 14.⑧% by mass, even more preferably 3.3 to 12.5% by mass, even more preferably 4.0 to 11.2% by mass, and particularly preferably 5.4 to 9.3% by mass. Within these ranges, there is a tendency that the yogurt can be frozen and thawed while maintaining the texture.

[0018] <Insoluble dietary fiber> The yogurt preferably contains insoluble dietary fiber in addition to the water-soluble dietary fiber. The insoluble dietary fiber means indigestible components in foods that are insoluble in solvents such as water and are not digested or are difficult to be digested by human digestive enzymes. By containing the insoluble dietary fiber, it is possible to prevent the separation of the liquid component when the yogurt is thawed after freezing while suppressing the sweetness. As the insoluble dietary fiber, for example, celluloses, chitin, chitosan, etc. can be used, and these can be used alone or in combination of two or more.

[0019] Specific examples of celluloses include natural cellulose, finely powdered cellulose, methylcellulose, carboxymethylcellulose, hydroxypropylmethylcellulose, acetylated cellulose, and ethylcellulose. The weight-average molecular weight of celluloses is preferably 340 to 2,000,000, more preferably 340 to 100,000, even more preferably 340 to 10,000, even more preferably 340 to 5,000, and particularly preferably 340 to 2,000.

[0020] Chitin can be derived from the exoskeletons of crustaceans or insects. Chitosan can be obtained by deacetylating chitin through hydrolysis. The degree of deacetylation of chitosan is preferably 60-90%. The weight-average molecular weight of chitin or chitosan is preferably 50,000-100,000, and more preferably 60,000-90,000.

[0021] The water-insoluble dietary fiber content is preferably 1.0 to 9.0% by mass of the yogurt's solid content, more preferably 1.3 to 7.0% by mass, even more preferably 1.7 to 5.0% by mass, and particularly preferably 2.0 to 3.0% by mass.

[0022] The yogurt of the present invention contains one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin, thereby suppressing the separation of liquid components when thawed after freezing. The separation of liquid components when thawed after freezing can be evaluated by the syneresis rate shown in the following formula, when Ag of yogurt, which has been stored at -20°C for one month and then at 4°C for 15 hours, is left to stand on a 500 μm mesh sieve at 25°C for two hours, and the mass of liquid that falls below the sieve is Bg. (Formula) Separation rate (%)=B / A×100 The water separation rate is preferably 45% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 25% by mass or less. The lower limit of the water separation rate is preferable as low as possible and is not particularly limited, but is generally 0.1% by mass or more.

[0023] <Optional ingredients> The yogurt of the present invention may contain, in addition to water-soluble dietary fiber and water-insoluble dietary fiber, optional components as described below.

[0024] The pH of the yogurt of the present invention is preferably 4.0 to 5.0, and more preferably 4.2 to 4.7. If the pH is below 4.2, the acidity may increase and the flavor may decrease, and if the pH is below 4.0, the acidity may increase even further and the flavor may decrease.

[0025] <<Composition for improving the quality of yogurt>> The yogurt quality-improving composition of the present invention is characterized by containing one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin.

[0026] The quality-improving composition may contain a single water-soluble dietary fiber selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin, or a combination of two or more. The total content of the water-soluble dietary fiber in the quality-improving composition is preferably 50 to 95% by mass, more preferably 60 to 93% by mass, and even more preferably 70 to 90% by mass.

[0027] The quality-improving composition may contain water-soluble dietary fiber selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin, as well as ingredients commonly found in yogurt production materials, such as excipients, stabilizers, emulsifiers, solvents, and oils and fats.

[0028] The yogurt quality improvements achieved by the yogurt quality-improving composition of the present invention include suppression of syneresis, suppression of graininess, improvement of appearance, and improvement of taste. It is preferable that one or more of these improvements are achieved, and it is more preferable that two or more of these improvements are achieved.

[0029] Suppression of syneresis refers to the suppression of separation of liquid components when yogurt is thawed after freezing. In yogurt containing the yogurt quality improving composition of the present invention, the syneresis rate represented by the above formula is preferably 45% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0030] The roughness is evaluated based on the abrasion degree measurement method using a creep meter, as described in the examples. The degree of roughness of yogurt containing the yogurt quality improving composition of the present invention is preferably 100% or less, more preferably 90% or less, even more preferably 80% or less, and even more preferably 70% or less, of the degree of roughness of yogurt without the yogurt quality improving composition of the present invention.

[0031] The appearance is evaluated based on the WH value and YI value measured by the method described in the examples. In yogurt containing the yogurt quality improving composition of the present invention, it is preferable that at least one of the WH value and YI value is equal to or greater than that of yogurt without the yogurt quality improving composition of the present invention, and it is more preferable that both the WH value and YI value are equal to or greater than that of yogurt without the yogurt quality improving composition of the present invention.

[0032] The taste is evaluated based on the sensory evaluation method for flavor described in the examples. In yogurt containing the yogurt quality-improving composition of the present invention, it is preferable that the sensory evaluation result for flavor is equal to or better than that of yogurt without the yogurt quality-improving composition of the present invention, and more preferably that it is superior to that of yogurt without the yogurt quality-improving composition of the present invention.

[0033] <<Yogurt manufacturing method>> The method for producing the yogurt of the present invention is not particularly limited and can be produced in the same way as general yogurt. Examples of the method for producing the yogurt of the present invention include a method that includes a raw material mixing step and a fermentation step.

[0034] One or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin may be mixed with other ingredients during the ingredient mixing process, or added to the fermented yogurt after the fermentation process. However, it is preferable to mix them during the ingredient mixing process because they mix more uniformly with other ingredients.

[0035] In the raw material mixing process, raw milk, one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharide, indigestible dextrin, and inulin, a starter, water-insoluble dietary fiber as needed, and optional components are mixed together. Examples of raw milk include raw milk, cow's milk, special milk, adjusted milk, low-fat milk, non-fat milk, and processed milk. The raw milk content is preferably 60-99% by mass, more preferably 65-97% by mass, even more preferably 70-95% by mass, and even more preferably 80-93% by mass of the total mass of yogurt.

[0036] As a starter, Lactobacillus, Lactococcus, Streptococcus, Pediococcus, Leuconostoc, Bifidobacterium, etc., can be used. Alternatively, fermented yogurt containing these microorganisms may be used as a starter. The starter content is preferably 1 to 10% by mass, more preferably 2 to 8% by mass, and even more preferably 2.5 to 5.5% by mass, of the total mass of the yogurt.

[0037] The content of one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin is preferably 8 to 50% by mass of the solid content of the yogurt, more preferably 10 to 48% by mass, even more preferably 15 to 43% by mass, even more preferably 18 to 40% by mass, and particularly preferably 23 to 25% by mass. Furthermore, the content of water-soluble dietary fibers is preferably 1.5 to 16.0% by mass of the total mass of the yogurt, more preferably 2.1 to 14.8% by mass, even more preferably 3.3 to 12.5% ​​by mass, even more preferably 4.0 to 11.2% by mass, and particularly preferably 5.4 to 9.3% by mass.

[0038] The content of water-insoluble dietary fiber is preferably 1.0 to 9.0% by mass, more preferably 1.3 to 7.0% by mass, even more preferably 1.7 to 5.0% by mass, and particularly preferably 2.0 to 3.0% by mass, based on the solid content of the raw material mixture. Furthermore, the content of cellulose is preferably 0.01 to 5% by mass, more preferably 0.1 to 4% by mass, and even more preferably 0.5 to 3% by mass, based on the total mass of the yogurt.

[0039] Optional ingredients include dairy products other than raw milk, sugars, stabilizers, emulsifiers, flavorings, oils and fats, colorings, flavoring agents, and antioxidants.

[0040] Examples of dairy products other than raw milk include skim milk powder, cream, concentrated whey, concentrated milk, skimmed concentrated milk, unsweetened condensed milk, unsweetened skimmed condensed milk, sweetened condensed milk, sweetened skimmed condensed milk, whole milk powder, cream powder, whey powder, protein-concentrated whey powder, buttermilk powder, sweetened milk powder, prepared milk powder, and fermented milk. The content of dairy products other than raw milk is preferably 1 to 10% by mass, and more preferably 4 to 9% by mass, of the total mass of yogurt.

[0041] Examples of sugars include granulated sugar, refined sugar, glucose, sucrose, fructose, maltose, stevia, sucralose, sorbitol, arabinose, trehalose, xylose, xylitol, maltitol, erythritol, mannitol, fructooligosaccharides, galactooligosaccharides, lactulose oligosaccharides, raffinose, and honey. The sugar content is preferably 0.5 to 10% by mass of the total mass of the yogurt.

[0042] The yogurt of the present invention may also be unsweetened yogurt. In yogurt containing sugars, water molecules are trapped by the sugars, so the separation of liquid components tends to be suppressed when thawed after freezing, regardless of the presence or absence of water-soluble dietary fiber such as cyclic tetrasaccharides. On the other hand, in unsweetened yogurt, the separation of liquid components is significant when thawed after freezing if water-soluble dietary fiber is not present, so it is easier to enjoy the benefit of suppressing the separation of liquid components by including water-soluble dietary fiber. In the case of unsweetened yogurt, the sugar content is less than 0.5% by weight, preferably 0.3% by weight or less, and more preferably 0.1% by weight or less.

[0043] Examples of stabilizers include gum arabic, carrageenan, alginic acid (salt), pectin, guar gum, tara gum, locust bean gum, tamarind seed gum, psyllium seed gum, glucomannan, gelan gum, xanthan gum, pullulan, curdlan, gelatin, and starch. The stabilizer content is preferably 0.01 to 2% by mass of the total mass of the yogurt.

[0044] Examples of emulsifiers include monoglycerides or their derivatives, sucrose fatty acid esters, polyglycerol fatty acid esters, propylene glycol fatty acid esters, polyglycerol condensed ricinoleic acid esters, calcium stearoyl lactylate, and sodium stearoyl lactylate. The emulsifier content is preferably 0.01 to 2% by mass of the total mass of the yogurt.

[0045] Examples of flavorings include yogurt flavorings, fruit flavorings, and plant flavorings. Examples of fruits used for fruit flavorings include citrus fruits, strawberries, peaches, apples, grapes, pineapples, mangoes, melons, and bananas. The flavoring content is preferably 0.001 to 1% by mass of the total mass of yogurt.

[0046] Examples of oils and fats include soybean oil, corn oil, safflower oil, olive oil, palm oil, rapeseed oil, rice bran oil, coconut oil, and palm kernel oil. The oil and fat content is preferably 0.01 to 2% by mass of the total mass of the yogurt.

[0047] Examples of pigments include red yeast rice pigment, gardenia, lac, cochineal, and carotene. The pigment content is preferably 0.001 to 0.2% by mass of the total mass of the yogurt.

[0048] Examples of flavorings include citrus fruits, strawberries, peaches, apples, grapes, pineapples, mangoes, melons, bananas, jelly, agar, almond tofu, and nata de coco. The flavoring content is preferably 1 to 20% by mass of the total mass of the yogurt.

[0049] Examples of antioxidants include vitamin A, carotenoids, vitamin C, vitamin E, selenium, flavonoids, polyphenols, lycopene, lutein, and lignans. The antioxidant content is preferably 0.001 to 0.1% by mass of the total mass of the yogurt.

[0050] The mixing order of each component in the raw material mixing process is not particularly limited; all raw materials may be mixed simultaneously or in any order. When using materials that are difficult to dissolve, such as skim milk powder or water-insoluble dietary fiber, these poorly soluble materials may be added to the raw milk and dissolved or dispersed by high-speed stirring before being mixed with the other materials. Examples of high-speed stirring conditions include stirring at 3000-5000 rpm for 5-10 minutes using a high-speed homogenizer.

[0051] The milk solids content in the raw material mixture is preferably 5 to 20% by mass, more preferably 5.5 to 15% by mass, and even more preferably 6 to 10% by mass. Within these ranges, it is easy to achieve a milk-derived flavor and a thick texture. The milk solids content refers to the total amount of milk fat and non-fat milk solids.

[0052] It is preferable to sterilize the mixture after the raw material mixing process and before the fermentation process. Suitable sterilization conditions include heat sterilization at 80-90°C for 10-20 minutes.

[0053] The yogurt of the present invention may be manufactured by a pre-fermentation method, in which the yogurt is filled into containers after fermentation, or by a post-fermentation method, in which the yogurt is fermented after being filled into containers. When manufactured by the post-fermentation method, the yogurt is filled into containers after the mixing of raw materials and before the fermentation process.

[0054] In the fermentation process, the mixture of raw materials is fermented. The fermentation temperature is not particularly limited, but is preferably 25°C to 50°C, more preferably 30°C to 50°C, even more preferably 37°C to 45°C, and even more preferably 40°C to 45°C. The fermentation time is not particularly limited, but is preferably 1 to 30 hours, more preferably 2 to 24 hours, and even more preferably 3 to 12 hours. If fermentation proceeds excessively and the pH becomes too low, the acidity will increase and the flavor will deteriorate, so it is preferable to stop fermentation when a predetermined pH is reached. The pH at the end of fermentation is preferably pH 4.0 to 5.0, and more preferably pH 4.2 to 4.7.

[0055] When yogurt is produced using the pre-fermentation method, it is filled into containers after the fermentation process. Alternatively, if necessary, the fermented yogurt may be crushed after the fermentation process before being filled into containers. Methods of crushing include stirring to break down the texture and using a mesh.

[0056] The yogurt of the present invention may be frozen after production. For frozen storage, it is preferable to first rapidly cool the yogurt after production and then store it in a frozen state. Examples of rapid cooling conditions include letting it stand at -20 to -40°C for 1 to 3 hours. The storage temperature in the frozen state is preferably -5 to -25°C. The frozen storage period is not particularly limited, but is generally 30 to 180 days. Examples of thawing conditions after frozen storage include letting it stand at 1 to 25°C for 12 to 24 hours. [Examples]

[0057] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples. Hereinafter, unless otherwise specified, "parts" or "%" means "parts by mass" or "% by mass," respectively.

[0058] <Example 1> Yogurt for Example 1 was prepared to have the composition shown in Table 1. Specifically, it was prepared through the following steps (1) to (6). (1) Milk (unprocessed milk, Nippon Rakuno Kogyo Co., Ltd.) and skim milk powder (moisture content 9.6%, manufactured by Yotsuba Dairy Co., Ltd.) and cellulose (Ceolus RC-591, moisture content 0%, water-insoluble dietary fiber concentration 89%, soluble dietary fiber concentration 11%, Asahi Kasei Corporation) were added to a glass beaker. The mixture was then stirred for 10 minutes at a rotation speed of 4500 rpm using a high-speed homomixer (HM-310, AS ONE Corporation) while maintaining a temperature of 55°C in a constant temperature bath to disperse the mixture. (2) To (1), cyclic tetrasaccharide syrup (Tetra Ring®, 29% moisture content, 51.1% water-soluble dietary fiber content, Nagase Vita Co., Ltd.) was added and mixed with a spatula. (3)(2) was sterilized by heating in a steam convection oven (MIC-6SA3, manufactured by Hoshizaki Corporation) in steam mode at 85°C for 15 minutes, then left to stand at room temperature and cooled to 43°C. (4)(3) was mixed with commercially available plain yogurt (Meiji Bulgaria Yogurt LB81 Plain, 88% water, 9.5% non-fat milk solids, 3.0% milk fat, manufactured by Meiji Co., Ltd.) as a starter, and stirred with a spatula. (5)(4) was fermented at 43°C using a dough conditioner (Toctorol Parte, PDD1-S2A-S, Tokura Shoji Co., Ltd.) until the pH reached 4.7, and then dispensed into 500 ml glass containers. (6)(5) was frozen at -40°C for 1 hour using a rapid freezer (blast chiller & shock freezer, HBC-6A3, Hoshizaki Corporation), and then stored at -20°C for 1 month using a refrigerator (Fujimac Corporation).

[0059] <Examples 2-3> Yogurts for Examples 2 and 3 were prepared in the same manner as in Example 1, except that indigestible dextrin (Fibersol 2, 5% moisture, 85% water-soluble dietary fiber concentration, manufactured by Matsutani Chemical Industry Co., Ltd.) and inulin (Fuji FF, 5% moisture, 91.8% water-soluble dietary fiber concentration, manufactured by Fuji Sugar Co., Ltd.) were used instead of cyclic tetrasaccharide syrup as water-soluble dietary fiber.

[0060] <Example 4> Yogurt for Example 4 was prepared in the same manner as in Example 1, except that cellulose was not added.

[0061] <Comparative Example 1> Comparative Example 1 yogurt was prepared in the same manner as in Example 1, except that cellulose and cyclic tetrasaccharide syrup as water-soluble dietary fiber were not added.

[0062] <Comparative Example 2> The yogurt for Comparative Example 2 was prepared using the same method as for Comparative Example 1, except that the post-fermentation freezing step was replaced with refrigeration at 4°C for one month.

[0063] <Comparative Example 3> Comparative Example 3 yogurt was prepared in the same manner as in Example 1, except that cyclic tetrasaccharide syrup was not added as a water-soluble dietary fiber.

[0064] (Evaluation method) For the yogurts of Examples 1-4 and Comparative Examples 1-3, the syneresis rate, appearance (color), texture, and sensory evaluation (flavor) were measured and evaluated using the methods described below. The evaluation results are shown in Table 1.

[0065] <Separation rate> (1) Examples 1-4 and Comparative Examples 1 and 3, which were stored for one month under freezing conditions at -20°C, were thawed for 15 hours at 4°C before use, and 50g portions were placed on a 500μm mesh stainless steel sieve (18cm in diameter). Comparative Example 2, which was stored under refrigeration at 4°C for one month, was used in the test as is. (2) The mixture was left standing at 25°C for 2 hours, and the weight of the water that fell into the bowl placed under the mesh was measured. (3) The percentage of water separation was calculated using the following formula. Water separation rate (%) = Weight of water that fell into the bowl (g) / Total amount of sample (g) The average of the results from three tests was calculated and used as the syneresis rate of the frozen yogurt.

[0066] <Appearance (Color)> (1) Examples 1-4 and Comparative Examples 1 and 3, which were stored for one month under frozen conditions at -20°C, were thawed for 15 hours at 4°C before being used in the test. Comparative Example 2, which was stored under refrigeration at 4°C for one month, was used in the test as is. (2) Using a color difference meter (COLOR AND COLOR DIFFERENCE METER, Tokyo Denshoku Co., Ltd.), the WH value (intensity of whiteness) and YI value (intensity of yellowness) of the top surface of the test sample were measured, and the average value of the results from three tests was calculated to evaluate the color of the frozen yogurt.

[0067] <roughness> (1) Examples 1-4 and Comparative Examples 1 and 3, which were stored for one month under frozen conditions at -20°C, were thawed for 15 hours at 4°C before being used in the test. Comparative Example 2, which was stored under refrigeration at 4°C for one month, was used in the test as is. (2) The total differential value (roughness) was calculated using the following formula, based on the differential values ​​and measurement points obtained from the measurements. Total differential value (roughness) = Σ|differential value × number of measurement points corresponding to the differential value| (Measurement conditions) Equipment: Creep meter (CREEP METER RE2-33005C, manufactured by Yamaden Co., Ltd.) Measurement method: friability measurement method Plunger: No. XZ6 (Height x Width = 20 x 20) Z-axis load: 0.010N X-axis sliding speed: 0.5 mm / sec X-axis sliding distance: 50mm The measurement involved two sliding movements, and the data obtained from the second movement was used as the measurement result. Similar tests were conducted three times to confirm that the same trend was observed.

[0068] <Sensory evaluation> (1) Examples 1-4 and Comparative Examples 1 and 3, which were stored for one month under frozen conditions at -20°C, were thawed for 15 hours at 4°C before being used in the test. Comparative Example 2, which was stored under refrigeration at 4°C for one month, was used in the test as is. (2) A trained panel of five people was given samples to consume and to evaluate each sample according to the following evaluation criteria. ○ was assigned 2 points, △ was assigned 1 point, and × was assigned 0 points. The total score of the five panel members for each sample was used as the evaluation of the flavor of the frozen yogurt. ·“Flavor” ○...It had a good flavor, similar to commercially available plain yogurt. △...It had a slightly different flavor compared to commercially available plain yogurt. ×...The flavor was significantly inferior compared to commercially available plain yogurt.

[0069] [Table 1]

[0070] Comparative Example 1 showed a significantly increased syneresis rate and a significantly increased grittiness compared to Comparative Example 2, which was not frozen. Comparative Example 3, which contained only water-insoluble dietary fiber, had syneresis rate and grittiness equivalent to Comparative Example 1. In Examples 1 to 4, which contained both water-insoluble and soluble dietary fiber, syneresis rate and grittiness were reduced compared to Comparative Example 1, despite being frozen. In particular, Example 1 showed good results in all evaluations of syneresis rate, whiteness, yellowness, grittiness, and flavor.

[0071] <Example 5> Yogurt for Example 5 was prepared to have the composition shown in Table 2. Specifically, yogurt for Example 5 was prepared in the same manner as in Example 1, except that cyclic tetrasaccharide (100% purity, 13% moisture content, 87% water-soluble dietary fiber concentration, manufactured by Nagase Vita Co., Ltd.) was used instead of cyclic tetrasaccharide syrup as the water-soluble dietary fiber.

[0072] (Evaluation method) The water separation rate, appearance (whiteness, yellowness), texture, and flavor were measured and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

[0073] [Table 2]

[0074] Comparative Example 1 showed a significantly increased syneresis rate and a significantly increased grittiness compared to Comparative Example 2, which was not frozen. Example 1, which contained cyclic tetrasaccharide syrup as a water-soluble dietary fiber, and Example 5, which contained cyclic tetrasaccharide, showed a significant reduction in syneresis rate and grittiness compared to Comparative Example 1. Furthermore, Examples 1 and 5 were all favorable in terms of evaluation results for whiteness, yellowness, and flavor.

[0075] <Examples 6-8> Yogurts for Examples 6-8 were prepared to have the formulations shown in Table 3. Specifically, yogurts for Examples 6-8 were prepared in the same manner as in Example 1, except that cyclic tetrasaccharide was used instead of cyclic tetrasaccharide syrup as the water-soluble dietary fiber, and the proportions were different from those in Example 5.

[0076] (Evaluation method) The water separation rate, appearance (whiteness, yellowness), texture, and flavor were measured and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0077] [Table 3]

[0078] Examples 5, 7, and 8, which contained 1.6 to 16% by weight of water-soluble dietary fiber relative to the total mass of yogurt, showed a significant reduction in syneresis and grittiness compared to Comparative Example 1. Furthermore, Examples 6, 7, and 8 all showed good results in evaluation of whiteness, yellowness, and flavor. On the other hand, Example 6 showed less reduction in syneresis and grittiness compared to Comparative Example 1.

[0079] <Examples 9-12> Yogurts for Examples 9-12 were prepared to have the formulations shown in Table 4. Specifically, yogurts for Examples 9-12 were prepared in the same manner as in Example 1, except that cyclic tetrasaccharide was used instead of cyclic tetrasaccharide syrup as the water-soluble dietary fiber, and the amount of water-insoluble dietary fiber was different from that in Example 5.

[0080] (Evaluation method) The water separation rate, appearance (whiteness, yellowness), texture, and flavor were measured and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

[0081] [Table 4]

[0082] Examples 5, 10, and 11, which contained 0.3 to 2.2% by weight of water-insoluble dietary fiber relative to the total mass of yogurt, showed a significant reduction in syneresis and grittiness compared to Comparative Example 1. Furthermore, Examples 5, 10, and 11 were all good in terms of evaluation results for whiteness, yellowness, and flavor. On the other hand, Examples 9 and 12 showed less reduction in grittiness compared to Comparative Example 1.

[0083] <Examples 13 and 14> Yogurts for Examples 13 and 14 were prepared to have the formulations shown in Table 5. Specifically, the yogurts for Examples 13 and 14 were prepared in the same manner as in Example 1, except that the water-insoluble dietary fiber was replaced with chitin (Kimika Chitin F, 0% moisture, 100% water-insoluble dietary fiber concentration, manufactured by Kimika Co., Ltd.) or chitosan (Kimika Chitosan LLP, 0% moisture, 100% water-insoluble dietary fiber concentration, manufactured by Kimika Co., Ltd.) instead of cellulose.

[0084] (Evaluation method) The water separation rate, appearance (whiteness, yellowness), texture, and flavor were measured and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0085] [Table 5]

[0086] In both Examples 13 and 14, where chitin or chitosan was used instead of cellulose as the water-insoluble dietary fiber, the syneresis rate and grittiness were significantly reduced compared to Comparative Example 1. Furthermore, the evaluation results for whiteness, yellowness, and flavor were all excellent.

Claims

1. Yogurt containing one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin.

2. The yogurt according to claim 1, further comprising water-insoluble dietary fiber.

3. The aforementioned cyclic tetrasaccharide is a sugar having the structure cyclo{→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→}. The yogurt according to claim 1 or 2.

4. The amount of water-soluble dietary fiber is 1.5 to 16% by mass of the total mass of the yogurt. The yogurt according to claim 1 or 2.

5. The yogurt according to claim 1 or 2, which is sugar-free.

6. The yogurt according to claim 1 or 2, wherein when Ag of yogurt, which has been stored at 20°C for one month and then at 4°C for 15 hours, is left to stand on a 500 μm mesh sieve at 25°C for 2 hours, Bg is the mass of liquid that falls to the bottom of the sieve, the syneresis rate shown by the following formula is 45% by mass or less. (Formula) Water separation rate (%) = B / A x 100

7. A composition for improving the quality of yogurt, comprising one or more water-soluble dietary fibers selected from the group consisting of cyclic tetrasaccharides, indigestible dextrin, and inulin.

8. The aforementioned quality improvement is one or more selected from the group consisting of suppression of syneresis, improvement of texture, improvement of appearance, and improvement of taste. The yogurt quality improvement composition according to claim 7.

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