Fermented cream and preparation method thereof

Abstract

To provide: fermented cream characterized by a gel structure stably soft against strain and imparting a smooth texture and a refreshing flavor; and a preparation method of the fermented cream capable of further improving stable softness against strain and a smooth texture.SOLUTION: The above-mentioned problem can be solved by: fermented cream prepared from cream containing 30 wt.% or more and 50 wt.% or less of fat as raw material and having storage elastic modulus of 6000 Pa or less at 5°C of product temperature and viscosity at a shear rate of 0.01 s-1 is 2000 Pa s or less; and a preparation method of the fermented cream including a step of agitating fermentation culture during the fermentation step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a high-fat cultured cream and a method for producing the same. [Background technology]

[0002] Fermented cream is made by fermenting cream with lactic acid bacteria to give it a sour taste and flavor. Fermented cream is a gel or solid cream that combines the richness and aroma of cream with the sour taste caused by lactic acid fermentation. One type of fermented cream is sour cream, which is made from cream and concentrated skim milk and contains 40% milk fat.

[0003] A typical example of a fermented cream food that does not use food additives is the French classic crème fraîche, which is used as a garnish for dishes, or mixed into sauces, soups, or doughs.

[0004] Currently, crème fraîche available in the domestic market has a hard gel structure, a thick texture with a solid feel and strong viscosity, and a distinctive cheese-like flavor. Furthermore, because these existing crème fraîche are produced without using food additives, the gel structure is easily destroyed by external strain, and maintaining product quality is an issue.

[0005] Prior art related to products classified as fermented cream has been reported, including a method for producing fermented cream made from fats and oils and food additives (Patent Document 1) and a method for preparing sour cream using cream and food additives (Patent Document 2). However, no method has been provided for large-scale production of high-fat cream by fermenting it without using food additives, such as crème fraîche.

[0006] A method for adjusting the hardness of sour cream by homogenizing the cream has been reported as a prior art (Non-Patent Document 1), but as shown in this document, the homogenization pressure limit for cream with a high fat content is low and the pressure adjustment range is narrow. Therefore, in the production of fermented cream with a fat content of 30% by weight or more and 50% by weight or less, it is not possible to adjust the hardness with a high degree of freedom by homogenization alone.

[0007] Regarding the prior art related to fermented milk, a production method has been reported that includes a step of stirring during the fermentation process in order to obtain liquid or paste-like fermented milk with few aggregates and good drinking properties (Patent Document 3). However, no method has been provided for improving the texture or providing a stable and soft gel structure without using food additives for products such as fermented cream, which has a relatively hard texture due to its high fat content. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 63-24846 [Patent Document 2] Japanese Patent Application Publication No. 2-31644 [Patent Document 3] JP 2018-201401 A [Non-patent literature]

[0009] [Non-Patent Document 1] Shoichiro Okuyama, Mitsuo Uozumi, Mamoru Tomita, 1994, Effect of homogenization pressure on the physical properties of sour cream, Journal of the Japan Society of Food Science and Technology Vol. 41 No. 6 Page. 407-412 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to solve the above problems, provide a fermented cream that does not contain any additives other than starter culture for fermenting the cream, is characterized by a soft gel structure that is stable against distortion and does not exist in conventional fermented creams on the market, and has a smooth texture and refreshing flavor, and to provide a method for producing a fermented cream that can further improve the stable softness against distortion and smooth texture. [Means for solving the problem]

[0011] The present inventors have discovered that by stirring the fermentation culture in the process of fermenting the raw material cream with lactic acid bacteria, it is possible to produce a fermented cream that is characterized by a soft gel structure that is stable against distortion and has a smooth texture and refreshing flavor, even without the addition of food additives, and have completed the fermented cream of the present invention and a method for producing a fermented cream that can further improve the softness and smooth texture that is stable against distortion. That is, the present invention includes the following configurations. [1] A fermented cream made from cream with a fat content of 30% by weight or more and 50% by weight or less, having a storage modulus of 6000 Pa or less at a product temperature of 5 ° C and a shear rate of 0.01 s -1 The fermented cream has a viscosity of 2000 Pa·s or less at 0.5°C. [2] The fermented cream according to [1] above, which does not contain any food additives. [3] The fermented cream according to [1], having a lactic acid acidity of 0.450 to 0.520%. [4] Steps (1) to (5) below (1) a mixing step of mixing a pasteurized or sterilized cream with a fat content of 30% by weight or more and 50% by weight or less with at least Lactobacillus thermophilus and / or Lactobacillus bulgaricus; (2) a fermentation step of fermenting the mixture obtained in the step (1) at 25 to 45° C. for 3 to 20 hours to obtain a fermentation culture; (3) an agitation step of agitating the fermentation culture in the step (2); (4) a cooling step of cooling the fermentation culture stirred in the step (3) to 10°C; (5) a step of filling a container with the fermentation culture cooled in the step (4); The method for producing fermented cream comprises: [5] A method for producing a fermented cream according to [4], which does not include a step of adding food additives. [6] The method for producing a fermented cream according to [4], wherein the stirring step (3) is a step of stirring at 10 to 60 rpm. [7] The method for producing fermented cream according to [4], wherein the stirring step (3) is carried out after the pH of the fermentation culture has reached 5.2 or less. [8] The method for producing fermented cream according to [4], wherein the stirring step (3) is a step in which stirring is performed continuously. [9] A fermented cream produced by the production method described in any one of [4] to [8]. Effect of the Invention

[0012] According to the present invention, no additives are added other than the seed bacteria for fermentation, and the storage modulus at a product temperature of 5° C. is 6000 Pa or less, and the shear rate is 0.01 s -1 The present invention provides a fermented cream with a fat percentage of 30% to 50% by weight, which has a viscosity of 2000 Pa s or less at room temperature, stable softness against strain, a smooth texture, and a refreshing flavor. The present invention also provides a method for producing a fermented cream that can further improve the stable softness against strain and the smooth texture. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a graph showing the change in viscosity of the fermentation cultures of the Comparative Example and Examples 1 to 3 after the stirring step. [Diagram 2] FIG. 2 is a diagram illustrating the dynamic viscoelasticity at a product temperature of 5° C. of the Comparative Example product and Example products 1 to 3 stored at 10° C. or lower for 7 days after production. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present inventors have conducted extensive research to solve the problem of providing a fermented cream that does not contain any additives other than a starter culture for fermenting the cream, that is characterized by a soft gel structure that is stable against strain, and that has a smooth texture and a refreshing flavor that is not found in conventional fermented creams on the market, and have found that by stirring the fermentation culture during the fermentation process, a fermented cream that is more stable against strain, has a smooth texture, and a refreshing flavor than conventional fermented creams can be obtained, and that by increasing the frequency of stirring during the fermentation process, the softness that is stable against strain and the smooth texture can be further improved. The present invention is based on the above findings. The present invention will now be described in further detail.

[0015] (Fermented cream) The fermented cream of the present invention contains fat derived from raw milk, components contained in raw milk other than the fat, and lactic acid bacteria, and does not contain food additives such as stabilizers, thickeners, emulsifiers, etc. An example of the fermented cream according to the present invention is creme fraiche. Crème fraiche is a type of sour cream, but it has a lower sourness and viscosity than sour cream and a higher fat content. The fermented cream of the present invention satisfies the following physical property parameters:

[0016] (Storage modulus at 5℃) The storage modulus of the fermented cream of the present invention at a product temperature of 5° C. after storage at 10° C. or less for 7 days after production is preferably 6000 Pa or less, more preferably 5000 Pa or less, and even more preferably 2500 Pa or less. There is no particular limit to the lower limit of the storage modulus, but it is about 1000 Pa. The storage modulus is used as an index of the hardness of food, and it can be said that the lower the storage modulus, the softer the fermented cream. According to the production method of the present invention, it was found that the storage modulus can be reduced by stirring during the fermentation process, and that the storage modulus can be further reduced by increasing the stirring frequency. It became possible to control the storage modulus by the stirring frequency.

[0017] (Shear rate 0.01 s at product temperature 5°C -1 Viscosity at The fermented cream of the present invention has a shear rate of 0.01 s at a product temperature of 5° C. after storage at 10° C. or less for 7 days after production. -1 The viscosity at is preferably 2000 Pa·s or less, more preferably 1200 Pa·s or less, and even more preferably 700 Pa·s or less. There is no particular lower limit to the viscosity, but it is about 300 Pa·s. The thick texture felt when fermented cream is put in the mouth is thought to be due to its high viscosity at low shear rates. Therefore, it can be said that the lower the viscosity of fermented cream at low shear rates, the less thick the fermented cream will be. According to the production method of the present invention, it has been found that the viscosity at low shear rates can be reduced by stirring during the fermentation process, and the viscosity can be further reduced by increasing the stirring frequency. It has become possible to control the viscosity at low shear rates by changing the stirring frequency.

[0018] (Dynamic Viscoelasticity) The fermented cream of the present invention has a strain of preferably 1.5% or more, more preferably 2.5% or more, and even more preferably 3.5% or more when the loss tangent at a product temperature of 5° C. after storage at 10° C. or less for 7 days after production is 1. There is no particular upper limit to the strain, but it is about 15%. The loss tangent is the ratio of the elastic term to the viscous term, and it is understood that the larger the amount of strain when the loss tangent is 1, the more stable the gel structure is against strain. According to the present invention, it has been found that the amount of strain at which the loss tangent becomes 1 can be increased by stirring during the fermentation process, and in particular, the amount of strain can be significantly increased by continuous stirring.

[0019] (Lactic acid acidity) The lactic acid acidity of the fermented cream of the present invention after storage at 10° C. or less for 7 days after production is preferably 0.450 to 0.520%, more preferably 0.460 to 0.500%, and even more preferably 0.470 to 0.490%. Lactic acid acidity can be measured according to the method described in "5. Method for measuring acidity of milk and dairy products" in "(7) Test methods for component standards of milk, etc." of the Ministerial Ordinance on Milk, etc. Specifically, it can be measured by mixing a sample with a phenolphthalein solution and performing neutralization titration with 0.1 mol / L sodium hydroxide solution.

[0020] (Ingredients for fermented cream) The cream used as the raw material in the present invention is defined in the Ministerial Ordinance on Milk Products, etc. as "raw milk, cow's milk or special milk from which components other than milk fat have been removed, resulting in a milk fat content of 18.0% or more." In particular, in the present invention, from the viewpoint of producing "crème fraîche," the fat percentage of the cream is preferably 30% by weight or more and 50% by weight or less, more preferably 30% by weight or more and 40% by weight or less, and even more preferably 32% by weight or more and 38% by weight or less. In addition, "raw milk" as used herein refers to "milk from cows as it is milked" as defined in the Ministerial Ordinance on Milk Products, etc. Cream can be produced by a commonly used method, for example, by heating raw milk to about 35 to 50° C. and separating it from skim milk by centrifugation. The fat content of the cream can also be adjusted appropriately depending on the product to be produced. The milk fat content of the cream used as the raw material can be measured according to the method described in "(7) Test methods for component standards of milk, etc." of the Ministerial Ordinance on Milk, etc., "3. Quantitative method for milk fat and milk protein content of milk and dairy products", "b. Quantitative method for milk fat content in concentrated milk, unsweetened condensed milk, sweetened condensed milk, whole milk powder, cream powder, sweetened milk powder and cream".

[0021] (Ingredients included) The fermented cream of the present invention contains fat derived from raw milk, components contained in raw milk other than the fat, and lactic acid bacteria, and does not contain any other food additives, and has a soft gel structure stable against distortion, and can realize a fermented cream that exhibits a smooth texture and a refreshing flavor. Therefore, in order to maximize the benefits of the present invention, it is preferable that the fermented cream of the present invention does not contain any food additives. Examples of food additives include stabilizers and thickeners that affect the gel structure in particular. More specifically, agar, pectin, carrageenan, gellan gum, gelatin, xanthan gum, locust bean gum, guar gum, guar gum hydrolyzate, tara gum, alginic acid, sodium alginate, etc., and emulsifiers, such as lecithin, polyglycerin fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, polysorbates, glycerin fatty acid esters, saponins, etc., and it is preferable that these are not included. However, this does not preclude the inclusion of flavorings or seasoning ingredients (such as sweeteners) for flavoring and ensuring palatability, as long as the effects of the present invention are not impaired.

[0022] (Lactic acid bacteria used) Examples of starters to be added to and mixed (inoculated) with cream, which is the raw material of the fermented cream of the present invention, include one or more lactic acid bacteria selected from the genus Streptococcus and Lactobacillus. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus are preferred, and the lactic acid bacteria may be used alone or in combination. In the present invention, the starter may contain known lactic acid bacteria in addition to the above lactic acid bacteria. Examples of known lactic acid bacteria include Lactobacillus gasseri, Lactococcus lactis, Lactococcus cremoris, and Bifidobacterium Longum. The method for mixing (inoculating) the starter is not particularly limited, and any method commonly used in the production of fermented cream can be used as appropriate. The amount of starter added can be appropriately set according to the amount used in known methods for producing fermented cream, as long as the fermentation of the cream proceeds smoothly, and is, for example, preferably 10 to 30 U / 100 kg, more preferably 15 to 25 U / 100 kg, and even more preferably 18 to 22 U / 100 kg based on the weight of the cream.

[0023] (Production method of fermented cream) The method for producing the fermented cream of the present invention will now be described.

[0024] The method for producing the fermented cream of the present invention is (1) a mixing step of mixing a pasteurized or sterilized cream with a fat content of 30% by weight or more and 50% by weight or less with at least Lactobacillus thermophilus and / or Lactobacillus bulgaricus; (2) a fermentation step of fermenting the mixture obtained in the step (1) at 25 to 45° C. for 3 to 20 hours to obtain a fermentation culture; (3) an agitation step of agitating the fermentation culture in the step (2); (4) a cooling step of cooling the fermentation culture stirred in the step (3) to 10°C; (5) a step of filling a container with the fermentation culture cooled in the step (4); Equipped with.

[0025] As described above, it is preferable that the method for producing the fermented cream according to the present invention does not include a step of adding food additives, etc. that may have an effect on the gel structure. According to the method for producing fermented cream of the present invention, the hardness of the fermented cream can be freely adjusted to meet the demand without mixing food additives. When flavorings or seasonings (such as sweeteners) are added to the extent that the effect of the present invention is not adversely affected in order to provide flavor or ensure palatability, it is preferable to add them during the raw material mixing step (1) or the container filling step (5).

[0026] (Pasteurization or sterilization of cream) The pasteurization or sterilization of the cream as a raw material can be carried out under conditions such as low-temperature pasteurization in which the cream is heated at 63-65°C for 30 minutes in a holding state, continuous low-temperature pasteurization in which the cream is heated continuously at 65-68°C for 30 minutes, high-temperature pasteurization (HTLT) in which the cream is heated at 75°C or higher for 15 minutes or more in a holding state, high-temperature short-time pasteurization (HTST) in which the cream is heated continuously at 72°C or higher for 15 seconds or more, or ultra-high-temperature pasteurization (UHT) in which the cream is heated at 120-150°C for 1-3 seconds, and there are no limitations as long as the conditions are those used for producing fermented cream. In the production method of the present invention, pasteurization or sterilization is preferably carried out under the conditions of the HTST method or UHT method. The equipment used for pasteurizing or sterilizing the cream may be any of a plate heat exchanger, a tube pasteurizer, a thermocylinder, a Joule heating device, a tank used for batch pasteurization, and a combination of these, but is not limited to these, as long as it can be used for producing fermented cream. In this specification, "sterilization" means treating the cream at a high temperature to reduce the number of microorganisms in the cream. In addition, in the present invention, "sterilization" means treating the cream at a high temperature to make the cream germ-free.

[0027] (Homogenization of cream) The cream, which is the raw material in the production method of the present invention, can be homogenized as necessary. The hardness of the fermented cream, which is the final product, can be adjusted by homogenizing the raw material cream. However, as mentioned above, the range of homogenization pressure that can be applied to the cream when producing a fermented cream with a high fat content is narrow. Therefore, the homogenization pressure is 0.5 to 5.0 MPa, preferably 0.8 to 2.5 MPa, and more preferably 1.0 to 2.0 MPa, from the viewpoint of obtaining a soft gel structure and a smooth texture of the fermented cream.

[0028] (Mixing process) In the production method of the present invention, the "mixing step" refers to a step of adding a starter to the pasteurized or sterilized cream and mixing. The mixing (inoculation) of the starter can be carried out by a method of directly adding the starter to the cream, a method of adding a solution in which the starter has been dissolved in advance, or the like, but is not particularly limited to these methods as long as the fermented cream of the present invention can be produced.

[0029] (Fermentation process) In the production method of the present invention, the "fermentation step" refers to a step of fermenting cream with a starter. The fermentation conditions can be appropriately set in consideration of the consistency and flavor of the fermented cream, the type of starter used, the amount of starter added, etc. Specifically, the fermentation temperature can be preferably 20 to 45°C, more preferably 25 to 35°C, and even more preferably 27 to 33°C, in view of the fermentation temperature range of cream. Under such temperature conditions, lactic acid bacteria are generally easy to be active, so fermentation can proceed efficiently. In addition, the fermentation time can be appropriately adjusted based on the lactic acid acidity of the fermentation culture. For example, in view of the fact that the fermented cream obtained by the production method of the present invention has a refreshing flavor, the lactic acid acidity at the end of fermentation can be preferably 0.450 to 0.520%, more preferably 0.460 to 0.500%, and even more preferably 0.470 to 0.490%. The lactic acid acidity of fermented milk can be measured according to the method described in "5. Method for measuring the acidity of milk and dairy products" in the "Testing methods for component standards of milk, etc." of the Ministerial Ordinance on Milk, etc. Specifically, the lactic acid acidity can be measured by mixing a sampled sample with a phenolphthalein solution and performing neutralization titration with a 0.1 mol / L sodium hydroxide solution. The fermentation time may be adjusted based on the lactic acidity of the fermentation culture as described above, but may be a time usually adopted in the production of fermented cream, for example, 3 to 20 hours, 5 to 19 hours, or 8 to 18 hours. Fermentation can be terminated by lowering the temperature of the fermentation culture to outside the fermentation temperature range (20 to 45°C).

[0030] (stirring process) In the production method of the present invention, the "stirring step" refers to a step of stirring the fermentation culture gelled by fermentation in the fermentation step while fermenting, to obtain a uniform fermentation culture that is thoroughly stirred throughout the fermentation tank without bias. The stirring is started during the fermentation step, and therefore stirring can be performed in the fermentation tank where the fermentation step is being performed. The stirring in the fermentation step contributes to the stable softness and smooth texture of the fermented cream against distortion.

[0031] (stirring conditions) The stirring conditions in the stirring step will be described below. The stirring speed during the fermentation step is preferably relatively slow from the viewpoint of efficient fermentation by lactic acid bacteria and gel texture formed by fermentation. For example, it can be 10 to 60 rpm, more preferably 10 to 45 rpm, and even more preferably 10 to 30 rpm. A high stirring speed may increase the dissolved oxygen in the fermentation culture and inhibit the growth of lactic acid bacteria, causing fermentation delay. Furthermore, the gel texture formed by fermentation may be excessively destroyed, making it impossible to obtain a soft gel structure or smooth texture that is stable against distortion. The stirring may be performed continuously or intermittently. It can be selected according to the desired texture. In the case of intermittent stirring, the stirring time per one time is not particularly limited, but can be appropriately adjusted so that the stirring is sufficient within the capacity of the fermentation tank in which the cream is fermented, and the fermentation culture in the fermentation tank is in a uniform state without bias as a whole. In addition, a known paddle-type stirring blade or the like can be used in the stirring process.

[0032] Agitation during the fermentation process is preferably started when the pH of the fermentation culture reaches 5.2 or below, at which point gelation begins. On the other hand, if the stirring in the fermentation process is started just before the end of fermentation, the stirring speed needs to be increased in order to obtain a fermented cream with a stable softness and smooth texture against distortion, but a high stirring speed may excessively destroy the tissue formed by fermentation, making it impossible to obtain a fermented cream with a stable softness and smooth texture against distortion. In addition, if the timing of starting the stirring in the fermentation process is delayed, the fermentation culture becomes excessively hard, and problems such as being unable to stir with the stirring capacity of the fermentation tank arise. Therefore, the timing of starting the stirring in the fermentation process is preferably when the pH of the fermentation culture is 4.6 or higher, and more preferably when the pH is in the range of 5.2 or lower and 4.6 or higher. In addition, the timing for ending the stirring in the fermentation step is preferably when the pH of the fermentation culture is 4.5 or less, and more preferably when the pH is within the range of 4.5 or less and 4.0 or more.

[0033] In the production method of the present invention, the "cooling step" refers to a step of cooling the stirred fermentation culture. After fermentation, it is preferable to cool to a temperature of 10°C or lower. It is preferable that the cooling from the fermentation temperature to 10°C is carried out within 10 hours, more preferably within 5 hours, even more preferably within 3 hours, and particularly preferably within 1 hour. It is preferable that the cooling is carried out with stirring.

[0034] In the production method of the present invention, the "filling step" refers to a step of filling the cooled fermentation culture into a container. The container may be a paper or plastic cup-shaped container or bag.

[0035] (Feeling bloated) The "blistering" of fermented cream means a texture consisting of a solid feel and strong viscosity. Whether or not the fermented cream has a "blistering" can be evaluated by a sensory evaluation by a panelist. The panelists evaluate whether or not they "feel" the "blistering" when eating the fermented cream.

[0036] (Smooth texture) The "smooth texture" of fermented cream means a texture that feels soft and not solid when eaten. Whether or not fermented cream has a "smooth texture" can be evaluated by a panelist's sensory evaluation. The order of the "smooth texture" of fermented cream is as follows: "◎: very smooth", "◯: smooth", "△: slightly smooth", and "×: rough".

[0037] (Refreshing flavor) The "refreshing flavor" of fermented cream is thought to be derived from the lactic acidity (sourness), smooth texture (how easily sourness can be sensed), and aftertaste odor. Whether or not fermented cream has a "refreshing flavor" can be evaluated by a panel's sensory evaluation. The fermented cream is rated in order of "refreshing flavor" as follows: "◎: very refreshing", "◯: refreshing", "△: somewhat refreshing", and "×: has an unpleasant aftertaste".

[0038] (Flavor characteristics) The "flavor characteristics" of the fermented cream can be evaluated by a sensory evaluation by a panel of panelists. The "flavor characteristics" of the fermented cream are evaluated based on the intensity of sourness and the impression of the aftertaste when the panelists eat the fermented cream. EXAMPLES

[0039] Examples of the present invention will be described in detail below, but the present invention is not limited to these examples and various improvements can be made based on known techniques.

[0040] [Comparative Example] The cream adjusted to a fat content of 35% by weight was homogenized at 1 MPa, sterilized at 120°C or higher, and further homogenized at 1 MPa to obtain a raw material cream. The fat content was adjusted by centrifuging raw milk and using a standardized unit Tetra Alphast (manufactured by Tetra Pak) to obtain cream (the same applies in the following examples). A frozen starter consisting of Lactobacillus thermophilus and Lactobacillus bulgaricus was added to the raw material cream in an amount of 20 U / 100 kg and mixed. The temperature of the mixture was kept at 29°C to start fermentation. Fermentation was allowed to proceed for 16 hours from the start of fermentation. After 16 hours had passed from the start of fermentation, the fermentation culture was cooled to 10°C while stirring at 20 rpm. The cooled fermentation culture was filled into a container and stored in a refrigerator at 10°C or lower to obtain a comparative example.

[0041] [Example 1] The cream adjusted to a fat content of 35% by weight was homogenized at 1 MPa, sterilized at 120°C or higher, and further homogenized at 1 MPa to obtain raw material cream. A frozen starter consisting of Lactobacillus thermophilus and Lactobacillus bulgaricus was added to the raw material cream in an amount of 20 U / 100 kg and mixed. The temperature of the mixture was kept at 29°C to start fermentation. After about 12 hours from the start of fermentation, the mixture was stirred at 20 rpm for 1 minute, and then the stirring was repeated every 60 minutes. After 16 hours from the start of fermentation, the fermentation culture was cooled to 10°C while stirring at 20 rpm. The pH of the fermentation culture at the start of stirring (12 hours after the start of fermentation) was 4.74, and the pH at the end of stirring (16 hours after the start of fermentation) was 4.50 (the same applies in the following examples). The cooled fermentation culture was filled into a container and stored in a refrigerator at 10°C or lower to obtain Example Product 1.

[0042] [Example 2] The cream adjusted to a fat content of 35% by weight was homogenized at 1 MPa, sterilized at 120°C or higher, and further homogenized at 1 MPa to obtain a raw material cream. A frozen starter consisting of Lactobacillus thermophilus and Lactobacillus bulgaricus was added to the raw material cream in an amount of 20 U / 100 kg and mixed. The temperature of the mixture was kept at 29°C to start fermentation. After about 12 hours from the start of fermentation, the mixture was stirred at 20 rpm for 1 minute, and then the stirring was repeated every 30 minutes. After 16 hours from the start of fermentation, the fermentation culture was cooled to 10°C while stirring at 20 rpm. The cooled fermentation culture was filled into a container and stored in a refrigerator at 10°C or lower to obtain Example Product 2.

[0043] [Example 3] The cream adjusted to a fat content of 35% by weight was homogenized at 1 MPa, sterilized at 120°C or higher, and further homogenized at 1 MPa to obtain a raw material cream. A frozen starter consisting of Lactobacillus thermophilus and Lactobacillus bulgaricus was added to the raw material cream in an amount of 20 U / 100 kg and mixed. The temperature of the mixture was kept at 29°C to start fermentation. After about 12 hours had passed since the start of fermentation, the mixture was continuously stirred at 20 rpm until 16 hours had passed, and then the fermentation culture was cooled to 10°C while stirring at 20 rpm. The cooled fermentation culture was filled into a container and stored in a refrigerator at 10°C or lower to obtain Example Product 3.

[0044] [Test Example 1] (Change in viscosity of fermented culture after stirring process) The viscosity of the fermentation culture after the stirring step was measured as follows. 100 ml of the fermentation cultures of Comparative Example and Examples 1 to 3 were sampled 12 hours after the start of fermentation (start of stirring), and the viscosity was measured after 30 seconds at a rotation speed of 30 rpm using a B-type viscometer TVB10M (manufactured by Toki Sangyo Co., Ltd.). Sampling was then conducted every hour until 16 hours after the start of fermentation, and the viscosity of the fermentation cultures was measured by the same method as above. In addition, samples were also taken of the fermentation cultures when they were cooled to 10°C 16 hours after the start of fermentation, when they were stored at 10°C or less for 1 day after filling into a container, and when they were stored for 7 days, and the viscosity was measured by the same method as above. The results are shown in Table 1 and FIG. 1.

[0045] [Test Example 2] (Storage modulus) The storage modulus at a strain of 0.01% of the Comparative Example and Example Products 1 to 3 stored at 10°C or less for 7 days after production was measured using a dynamic viscoelasticity measuring device MCR302 (manufactured by Anton Paar Japan Co., Ltd.). The sample was kept at a temperature of 5°C during the measurement. The results are shown in Table 2.

[0046] [Test Example 3] (Shear rate 0.01 s -1 Viscosity at The comparative example products and example products 1 to 3 stored at 10°C or less for 7 days after production at a shear rate of 0.01 s -1 The viscosity at 100°C was measured using a dynamic viscoelasticity measuring device MCR302 (manufactured by Anton Paar Japan Co., Ltd.). The measurement was performed with the sample temperature adjusted to 5°C. The results are shown in Table 2.

[0047] [Test Example 4] (Dynamic Viscoelasticity) The dynamic viscoelasticity of the comparative example and example products 1 to 3, which were stored at 10°C or less for 7 days after production, was determined by measuring the loss tangent due to strain dependence when the strain amount was changed from 0.01% to 10%. The loss tangent was measured using a dynamic viscoelasticity measuring device MCR302 (manufactured by Anton Paar Japan Co., Ltd.). The measurement was performed with the sample temperature adjusted to 5°C. The results are shown in Figure 2.

[0048] [Test Example 5] (Lactic acid acidity) The lactic acid acidity of the comparative example product and example products 1 to 3 stored at 10°C or less for 7 days after production was measured by adjusting the temperature of the sample to 5°C, sampling, mixing with a phenolphthalein solution, and performing neutralization titration with a 0.1 mol / L sodium hydroxide solution. The results are shown in Table 2.

[0049] [Test Example 6] (Sensory evaluation) The sensory evaluation was performed by a trained panel of five experts. (Feeling bloated) The panelists evaluated whether the fermented cream had a "blistering" feeling by sensory evaluation. The "blistering" feeling of the fermented cream was evaluated based on whether the panelists "felt" or "did not feel" the blistering feeling when eating the fermented cream. The results are shown in Table 3. (Smooth texture) Whether the fermented cream had a "smooth texture" was evaluated by a panel of panelists. The fermented cream was ranked in order of "smooth texture" as "◎: very smooth," "◯: smooth," "△: slightly smooth," and "×: rough." The results are shown in Table 3. (Refreshing flavor) Whether the fermented cream had a "refreshing flavor" was evaluated by a panel of panelists. The order of whether the fermented cream had a "refreshing flavor" was rated as "◎: very refreshing", "◯: refreshing", "△: slightly refreshing", and "×: has an unpleasant aftertaste". The results are shown in Table 3. (Flavor characteristics) The "flavor characteristics" of the fermented cream were evaluated by a panel of panelists through sensory evaluation. The "flavor characteristics" of the fermented cream were evaluated based on the intensity of sourness and the impression of the aftertaste when the panelists ate the fermented cream. The results are shown in Table 3.

[0050] [Test Results] The results and discussion of the above test are shown below in the table.

[0051] [Table 1]

[0052] Table 1 and FIG. 1 show the results of measuring the viscosity of the fermentation cultures of the Comparative Example and Examples 1 to 3 at various times after the stirring step. By stirring the fermentation culture during the fermentation process, the viscosity of the fermentation culture at each time point generally decreased (Examples 1 to 3). In addition, the viscosity of the fermentation culture at each time point after the stirring process decreased as the frequency of stirring increased (Examples 1 to 3).

[0053] [Table 2]

[0054] Table 2 shows the pH, lactic acid acidity, storage modulus at 5°C, and shear rate 0.01 s at 5°C for the Comparative Example and Example Products 1 to 3 stored at 10°C or less for 7 days after production. -1 The results of viscosity measurements are shown. The pH of the fermented cream was 4.33 (Comparative Example, Examples 1 to 3). At similar pH values, the lactic acid acidity of the Comparative Example product and Examples 1 to 3 was 0.473% or more and 0.478% or less. The storage modulus of the fermented cream at a product temperature of 5°C and the shear rate of 0.01 s at a product temperature of 5°C after storage for 7 days after production were -1 The viscosity at a shear rate of 0.01 s at a product temperature of 5° C. decreased as the frequency of stirring during the fermentation process increased (Examples 1 to 3). -1 The viscosity at the time of the test was decreased (Examples 1 to 3).

[0055] FIG. 2 shows the strain-dependent loss tangent of fermented cream stored at 10°C or below for 7 days after production at a product temperature of 5°C when the strain is changed from 0.01% to 10%. The loss tangent is the ratio of the elastic term to the viscous term, and it is understood that the larger the amount of strain when the loss tangent is 1, the more stable the gel structure is against strain. From these results, the strain at which the loss tangent of the comparative example becomes 1 is 1.0%, whereas it is 2.0% for example product 2, 2.8% for example product 1, and 6.3% for example product 3. By stirring during the fermentation process, fermented cream that is more stable against strain was obtained (Examples 1 to 3). In particular, by continuous stirring (Example 3), a fermented cream that is particularly stable against strain was obtained compared to intermittent stirring (Examples 1 and 2).

[0056] [Table 3]

[0057] Table 3 shows the results of the sensory evaluation of the Comparative Example product and Example products 1 to 3 after storage at 10° C. or less for 7 days after production. (Feeling bloated) By continuous stirring during the fermentation process (Example 3), a fermented cream with no bulky texture was obtained. (Smooth texture) By stirring during the fermentation process, fermented cream with a smooth texture was obtained (Examples 1 to 3). In addition, the higher the frequency of stirring during the fermentation process, the smoother the fermented cream with a smoother texture was obtained (Examples 1 to 3). (Refreshing flavor) Continuous stirring during fermentation (Example 3) gave rise to a fermented cream with a particularly refreshing flavor. (Flavor characteristics) The Comparative Example product and Example products 1 to 3, which used Lactobacillus thermophilus and Lactobacillus bulgaricus as starters, had a slight sour taste and a light aftertaste. [Industrial Applicability]

[0058] The fermented cream has a characteristic soft gel structure that is stable against distortion, which is not found in fermented creams on the market today, and by providing a fermented cream that has a smooth texture and a refreshing flavor, new demand can be expected.

Claims

1. A fermented cream made from cream having a fat content of 30% by weight or more and 50% by weight or less, the cream having a storage modulus of 6000 Pa or less at a product temperature of 5° C. and a shear rate of 0.01 s -1 The fermented cream has a viscosity of 2000 Pa·s or less at 0.5° C.

2. The fermented cream according to claim 1, which does not contain any food additives.

3. The fermented cream according to claim 1, wherein the lactic acid acidity is 0.450 to 0.520%.

4. The following steps (1) to (5) (1) a mixing step of mixing a pasteurized or sterilized cream having a fat content of 30% by weight or more and 50% by weight or less with at least Lactobacillus thermophilus and / or Lactobacillus bulgaricus; (2) a fermentation step of fermenting the mixture obtained in the step (1) at 25 to 45° C. for 3 to 20 hours to obtain a fermentation culture; (3) a stirring step of stirring the fermentation culture in the step (2); (4) a cooling step of cooling the fermentation culture stirred in the step (3) to 10°C; (5) a step of filling a container with the fermentation culture cooled in the step (4); The method for producing fermented cream comprises:

5. The method for producing fermented cream according to claim 4, which does not include a step of adding a food additive.

6. The method for producing fermented cream according to claim 4, wherein the stirring step (3) is a step of stirring at 10 to 60 rpm.

7. The method for producing fermented cream according to claim 4, wherein the stirring step (3) is carried out after the pH of the fermentation culture has reached 5.2 or less.

8. The method for producing fermented cream according to claim 4, wherein the stirring step (3) is a step in which stirring is performed continuously.

9. A fermented cream produced by the method according to any one of claims 4 to 8.

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