Double-skin yoghourt and preparation method thereof

Abstract

The invention provides double-skin yoghourt and a preparation method thereof, the double-skin yoghourt is composed of a milk skin layer and a yoghourt layer, the milk skin layer is located on the yoghourt layer, and the hardness of the milk skin layer is not less than 200g. The double-skin yoghourt provided by the invention has the characteristics that the edges of the milk skin layers are smooth and wrinkle-free, and the double-skin yoghourt is not easy to damage in the transportation process.

Description

Technical Field

[0001] The invention relates to a double-skin yogurt, in particular to a double-skin yogurt and a preparation method thereof, and belongs to the field of food engineering. Background Art

[0002] Shuangpi milk is a popular after-meal dessert with a delicate and smooth texture, rich taste, and light sweetness. Yogurt is rich in nutrients and microorganisms that are beneficial to human health. Therefore, Shuangpi milk can be combined with yogurt to develop a double-skin yogurt.

[0003] In the current production process of double-skin yogurt, thickeners such as agar and sodium alginate and pyrophosphate are often used to treat the raw milk to obtain double-skin yogurt with a milk skin layer on the upper layer and a yogurt layer on the lower layer. However, this double-skin yogurt has the defects of more wrinkles on the edge of the milk skin layer and is easily damaged during transportation.

[0004] Therefore, developing a double-skin yogurt with smooth and wrinkle-free milk skin edge and not easily damaged during transportation has become a research direction. Summary of the invention

[0005] The invention provides a double-skin yogurt, which has the characteristics of smooth and wrinkle-free milk skin edge and is not easily damaged during transportation.

[0006] The present invention also provides a method for preparing double-skin yogurt, by which the above-mentioned double-skin yogurt can be prepared. The method has the characteristics of various types of prepared products and simple preparation process.

[0007] The invention provides a double-skin yogurt, wherein the double-skin yogurt consists of a milk skin layer and a yogurt layer, the milk skin layer is located above the yogurt layer, and the hardness of the milk skin layer is not less than 200g.

[0008] The double-skin yogurt as described above, wherein the hardness of the milk skin layer is 200-250g, the hardness of the yogurt layer is 150-200g, and the hardness difference between the milk skin layer and the yogurt layer is 45-55g.

[0009] As described above, the double-skin yogurt, wherein the milk skin layer is prepared from raw materials including light cream, cocoa butter, and mono- and diglycerol fatty acid esters, the light cream accounts for no less than 61.2% of the total mass percentage of the raw materials, and the cocoa butter accounts for no less than 28.4% of the total mass percentage of the raw materials.

[0010] As described above, the double-skin yogurt, wherein the raw materials for preparing the milk skin layer include, by mass percentage, 3-6% white sugar, 0.8-1.6% mono- and di-glycerol fatty acid esters, 61.2-64% light cream, and 28.4-35% cocoa butter.

[0011] The double-skin yogurt as described above, wherein the milk skin layer is obtained by a preparation method comprising the following steps:

[0012] 1) heating the cream to a temperature not lower than 50° C. to obtain hot cream;

[0013] 2) adding granulated sugar, mono- and di-glycerol fatty acid esters and cocoa butter to the hot cream and stirring to obtain the milk skin layer.

[0014] The double-skin yogurt as described above, wherein the raw materials for preparing the yogurt layer include, by mass percentage, 92.97-96.37% of raw milk, 3-6% of sweetener, 0.4-0.8% of thickener, 0.23-0.53% of stabilizer, and also includes a leavening agent.

[0015] The double-skin yogurt as described above, wherein the mass ratio of the milk skin layer to the yogurt layer is 1:99-1:499.

[0016] The present invention also provides a method for preparing double-skin yogurt, which comprises the following steps:

[0017] 1) mixing cream, cocoa butter, a sweetener and an emulsifier to obtain a first raw material liquid;

[0018] 2) Using the first raw material liquid to perform a filling process on the system including the yogurt layer to obtain the double-skin yogurt.

[0019] The present invention also provides another method for preparing double-skin yogurt, which comprises the following steps:

[0020] 1) mixing cream, cocoa butter, a sweetener and an emulsifier to obtain a first raw material liquid;

[0021] 2) mixing a thickener, a sweetener, a stabilizer and raw milk at a temperature above 50° C. and then adding a starter to obtain a second raw material liquid;

[0022] 3) sequentially filling the second raw material liquid and the first raw material liquid so that the first raw material liquid is located above the second raw material liquid to obtain a third raw material liquid;

[0023] 4) fermenting the third raw material liquid to obtain the double-skin yogurt.

[0024] The preparation method as described above, wherein, further comprises coagulating the first raw material at 2-6°C to obtain a milk skin layer.

[0025] The double-skin yogurt provided by the present invention consists of a milk skin layer and a yogurt layer, wherein the milk skin layer is located above the yogurt layer. Since the milk skin layer has a relatively high hardness, the double-skin yogurt has the characteristics of smooth and wrinkle-free edges of the milk skin layer and is not easily damaged during transportation. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0027] A first aspect of the present invention provides a double-skin yogurt, which consists of a milk skin layer and a yogurt layer, wherein the milk skin layer is located above the yogurt layer, and the hardness of the milk skin layer is not less than 200g.

[0028] The double-skin yogurt provided by the present invention is a product composed of two substances stacked up and down. According to the position, the substance located on the upper side is the milk skin layer, and the substance located on the lower side is the yogurt layer. At least part of the lower surface of the milk skin layer is in contact with the upper surface of the yogurt layer.

[0029] The hardness of the milk skin layer is not less than 200g. The present invention does not impose any further specific restrictions on the hardness of the milk skin layer, and the hardness of the milk skin layer can be not less than 200g. For example, a milk skin layer with a hardness of not less than 200g can be obtained by selecting suitable raw materials or defining a special preparation process.

[0030] The present invention does not impose any specific restrictions on the selection of the yogurt layer, and the yogurt layer can be selected from any type and any flavor of yogurt in the art, as long as it can support the milk skin layer so that it is located above the yogurt layer.

[0031] The double-skin yogurt provided by the present invention has a milk skin layer with high hardness and strong anti-deformation ability. Therefore, the double-skin yogurt has the characteristics of smooth and wrinkle-free milk skin layer edge and can withstand large bumps and remain intact during transportation.

[0032] Furthermore, in another double-skin yogurt provided by the present invention, the hardness of the milk skin layer is 200-250g, the hardness of the yogurt layer is 150-200g, and the hardness difference between the milk skin layer and the yogurt layer is 45-55g.

[0033] One of the characteristics of double-skin yogurt is that there are multiple components with different tastes in one product. When consumers eat double-skin yogurt, the taste differences between the multiple components enhance the consumer's eating experience. When the hardness of the milk skin layer, the hardness of the yogurt layer, and the hardness difference between the milk skin layer and the yogurt layer of double-skin yogurt meet the above conditions, it can bring consumers a better eating experience.

[0034] The present invention does not limit the type of yogurt contained in the yogurt layer, as long as the hardness of the yogurt layer is 150-200g. The yogurt layer can be yogurt prepared by conventional means in the art, or commercially available yogurt in the art.

[0035] In one embodiment, a milk cortex with a hardness of not less than 200g can be prepared from raw materials including cream and cocoa butter, wherein the cream accounts for not less than 61.2% of the total mass percentage of the raw materials, and the cocoa butter accounts for not less than 28.4% of the total mass percentage of the raw materials. Cream and cocoa butter are both raw materials with high fat content. When the milk cortex is prepared using raw materials containing cream and cocoa butter with a specific mass fraction, the prepared milk cortex also has a high fat content. The milk cortex with a higher fat content has a higher hardness and a smoother and more delicate surface. Therefore, the use of raw materials including the above-mentioned mass fractions of cream and cocoa butter can not only produce a milk cortex with a hardness of more than 200g, a smooth edge without wrinkles, and not easily damaged during transportation, but also make the surface of the milk cortex smoother and more delicate, and the aesthetics is significantly improved.

[0036] Furthermore, the inventors found that when the milk skin layer is prepared using raw materials comprising, by mass percentage, 3-6% white sugar, 0.8%-1.6% mono- and diglycerol fatty acid esters, 61.2-64% light cream, and 28.4-35% cocoa butter, a milk skin layer with a hardness of 200-250g can be obtained.

[0037] Among them, white sugar acts as a sweetener, making the milk skin sweet and delicious, which can enhance the consumer's eating experience; mono- and di-glycerol fatty acid esters can improve the stability of the raw materials, reduce the phenomenon of oil-water separation in the raw materials, and make the surface of the milk skin smoother and more delicate. Furthermore, since the above raw materials have a suitable mass ratio, the milk skin prepared using the above raw materials has a more prominent smooth and delicate surface.

[0038] The present invention does not impose any specific restrictions on the fat content of the cream, and cream with any fat content in commercial products can be used. In one embodiment, cream with a fat content of 35% is used. Due to the high fat content of this type of cream, the edge of the milk skin layer is smooth and wrinkle-free, it is not easy to be damaged during transportation, and the surface of the milk skin layer is smooth and delicate.

[0039] Furthermore, in the double-skin yogurt provided by the present invention, the milk skin layer with a hardness of 200-250g can be obtained by a preparation method comprising the following steps:

[0040] 1) heating the cream to a temperature not lower than 50° C. to obtain hot cream;

[0041] 2) Add sugar, mono- and di-glycerol fatty acid esters and cocoa butter to the hot cream and stir to obtain a milk skin layer.

[0042] It is understandable that in order to obtain a milk skin layer with a hardness of 200-250g, the above steps can be used according to the mass percentage of each raw material mentioned above.

[0043] The present invention does not impose any specific restrictions on the temperature of the hot cream, as long as it satisfies the condition of not less than 50° C. In one embodiment, the temperature of the hot cream is 50-60° C. A higher temperature of the hot cream can not only accelerate the dissolution of other solid raw materials, but also make the mixing more uniform, and the surface of the obtained milk skin layer is more smooth and delicate.

[0044] Furthermore, in order to make the raw materials mixed more uniformly, the stirring time during the mixing process is not less than 30 minutes.

[0045] The present invention does not limit the order of adding white sugar, mono- and di-glycerol fatty acid esters, and cocoa butter to the hot cream. White sugar, mono- and di-glycerol fatty acid esters, and cocoa butter can be added to the hot cream separately in any order, or several of the above raw materials can be pre-mixed in any combination and then added to the hot cream separately.

[0046] Furthermore, in order to kill microorganisms in the raw materials, extend the shelf life of the product, and ensure video safety, after the above step 2), the obtained milk skin layer is heated to 93-97°C for sterilization, and the sterilization time is 300-360 seconds. After the sterilization treatment is completed, the temperature can be lowered to 28-32°C for standby use.

[0047] In one embodiment, the raw materials for preparing the yogurt layer in the double-skin yogurt provided by the present invention include, by mass percentage: 92.97-96.37% raw milk, 3-6% sweetener, 0.4-0.8% thickener, 0.23-0.53% stabilizer, and also include a leavening agent.

[0048] The present invention does not impose any specific restrictions on the selection of raw milk, as long as the raw milk meets the requirement of preparing the yogurt layer. For example, the raw milk can be selected from at least one of fresh cow's milk, fresh goat's milk, fresh deer's milk, fresh camel's milk, pasteurized cow's milk, pasteurized goat's milk, pasteurized deer's milk, pasteurized camel's milk, reconstituted cow's milk, reconstituted goat's milk, reconstituted deer's milk and reconstituted camel's milk. In one embodiment, the raw milk is fresh cow's milk.

[0049] The present invention does not specifically limit the selection of sweeteners, as long as the sweeteners satisfy the requirement of making the yogurt layer sweet. For example, the sweeteners can be selected from at least one of white granulated sugar, brown granulated sugar, fructose syrup, xylitol, steviol glycosides, and erythritol. In one embodiment, the sweetener is white granulated sugar.

[0050] The role of the thickener is to increase the hardness of the yogurt layer, so that the yogurt layer and the milk skin layer form a suitable hardness difference, and improve the taste of the double skin yogurt. The higher the amount of thickener added, the greater the hardness of the yogurt layer. The present invention does not impose any specific restrictions on the selection of thickeners, as long as it can meet the role of increasing the hardness of the yogurt layer. In one embodiment, the thickener includes at least one of gelatin, agar, pectin, and modified starch. Among them, the gel strength of gelatin is required to be 240-259 Bloom g. The use of this kind of gelatin can further increase the hardness of the yogurt layer to meet the product's requirements for the hardness of the yogurt layer.

[0051] The function of the stabilizer is to make the mixed system more stable, reduce the oil-water separation phenomenon, and further improve the product taste. The present invention does not specifically limit the selection of the stabilizer, as long as it can meet the requirements of improving the stability of the mixed system. For example, the stabilizer can be selected from at least one of agar, pectin, and modified starch. In a specific embodiment, the stabilizer is hydroxypropyl distarch phosphate.

[0052] The starter can utilize the lactose in the raw material and convert it into lactic acid through fermentation, so that the raw milk becomes yogurt. The present invention does not limit the type of the starter, as long as it meets the requirement of converting lactose into lactic acid. In the present invention, the starter includes thermophilic streptococcus and bulgaricus lactobacillus, wherein the mass ratio of thermophilic streptococcus to bulgaricus lactobacillus is 1:1-1:3.

[0053] Except thermos streptococcus and Lactobacillus bulgaricus, the present invention does not limit other ingredients in the starter, as long as the requirement of not affecting the fermentation process is met. In one embodiment, the starter also comprises at least one of Bifidobacterium lactis, Streptococcus thermophilus, Bifidobacterium longum, Bifidobacterium infantis, Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus paracasei.

[0054] The present invention does not impose any specific restrictions on the amount of the leavening agent added, as long as it meets the requirement of converting lactose into lactic acid. In one embodiment, the amount of the leavening agent added is 1×10 9 -5×10 9 cfu / g.

[0055] The double-skin yogurt provided by the present invention has a yogurt layer prepared by using raw materials containing a certain mass fraction of a specific thickener and a stabilizer, so that the yogurt layer has stable properties and is not prone to water precipitation and gel precipitation, thereby further improving the appearance of the double-skin yogurt and thereby improving consumers' evaluation of the product.

[0056] It is easy to understand that since the double-skin yogurt provided by the present invention is composed of two parts, a milk skin layer and a yogurt layer, with different hardnesses, the difference in taste between the two parts improves the consumer's eating experience. Therefore, controlling the mass ratio of the milk skin layer and the yogurt layer taken by consumers when eating double-skin yogurt is crucial to improving the consumer's eating experience. The inventor found that when the mass ratio of the milk skin layer to the yogurt layer is greater than 1:499, the milk skin layer can completely cover the yogurt layer, and the edge of the container for holding the double-skin yogurt has no yogurt layer exposed, which is more beautiful; further, when the mass ratio of the milk skin layer to the yogurt layer is 1:99-1:499, when consumers use a spoon to take the double-skin yogurt from top to bottom, they can take the milk skin layer and the yogurt layer of appropriate mass at the same time, which can experience the different tastes brought by the milk skin layer and the yogurt layer, and will not feel greasy due to eating too much milk skin layer, thus having a better eating experience.

[0057] Considering the common container sizes for holding double-skin yogurt, in a specific embodiment, when the thickness ratio of the milk skin layer to the yogurt layer is 1:10-1:30, and / or the thickness of the milk skin layer is 2-8 mm, it can also enhance the consumer's eating experience.

[0058] Furthermore, in order to further enhance the consumer's eating experience, in one embodiment, the sugar content of the milk skin layer and the yogurt layer is the same. Double-skin yogurt with the same sugar content of the milk skin layer and the yogurt layer can provide a more consistent taste, which helps to improve consumer evaluation.

[0059] The second aspect of the present invention provides a method for preparing a double-skin yogurt, which is used to prepare any of the above-mentioned double-skin yogurts. The method comprises the following steps:

[0060] 1) mixing cream, cocoa butter, a sweetener and an emulsifier to obtain a first raw material liquid;

[0061] 2) The system including the yogurt layer is filled with the first raw material liquid to obtain double-skin yogurt.

[0062] The present invention does not impose any specific restrictions on the selection of cream, sweetener, and emulsifier, and the above raw materials can be selected from the range of raw materials mentioned above.

[0063] The present invention does not specifically limit the mixing order of the raw materials in step 1), and the raw materials can be mixed in any order. In one embodiment, the cream is heated to a temperature not less than 50°C to obtain hot cream, and then white sugar, mono- and di-glycerol fatty acid esters, and cocoa butter are added to the hot cream and stirred to obtain a first raw material liquid. This method can not only accelerate the dissolution of the raw materials by increasing the temperature of the mixing process, but also make the raw materials more evenly mixed, so that the surface of the milk skin layer in the double skin milk product is smoother and more delicate.

[0064] Furthermore, in order to make the raw materials mixed more uniformly, the stirring time during the mixing process is not less than 30 minutes.

[0065] It is understood that in order to kill the microorganisms in the raw materials and extend the shelf life of the product, after the above step 1) and before step 2), the first raw material liquid is further heated to 93-97°C for sterilization, and the sterilization time is 300-360 seconds. After the sterilization treatment is completed, the temperature can be lowered to 28-32°C for standby use.

[0066] In step 2), the yogurt is first filled into a container for selling double-skin yogurt to form a yogurt layer at the bottom of the container, and then the first raw material liquid is filled into the container containing the yogurt layer so that the first raw material liquid is located above the yogurt layer.

[0067] The present invention does not impose any specific restrictions on the selection of yogurt, and the yogurt can be selected from any type and any flavor of yogurt in the art, as long as it can support the milk skin layer so that it is located on the yogurt.

[0068] The preparation method of the double-skin yogurt provided by the present invention combines the milk skin layer with different types of yogurt layers after the milk skin layer is prepared, so the preparation method has the characteristic of preparing various types of products.

[0069] The present invention also provides another method for preparing double-skin yogurt, comprising the following steps:

[0070] 1) mixing cream, cocoa butter, a sweetener and an emulsifier to obtain a first raw material liquid;

[0071] 2) mixing a thickener, a sweetener, a stabilizer and raw milk at a temperature above 50° C. and then adding a starter to obtain a second raw material liquid;

[0072] 3) filling the second raw material liquid and the first raw material liquid in sequence so that the first raw material liquid is located above the second raw material liquid to obtain a third raw material liquid;

[0073] 4) fermenting the third raw material liquid to obtain double-skin yogurt.

[0074] The present invention does not impose any specific restrictions on the selection of the cream, sweetener and emulsifier in step 1), and the above raw materials can be selected from the range of raw materials mentioned above.

[0075] The present invention does not specifically limit the mixing order of the raw materials in step 1), and the raw materials can be mixed in any order. In one embodiment, the cream is heated to a temperature not less than 50°C to obtain hot cream, and then white sugar, mono- and di-glycerol fatty acid esters, and cocoa butter are added to the hot cream and stirred to obtain a first raw material liquid. This method can not only accelerate the dissolution of the raw materials by increasing the temperature of the mixing process, but also make the raw materials more evenly mixed, so that the surface of the milk skin layer in the double skin milk product is smoother and more delicate.

[0076] Furthermore, in order to make the raw materials mixed more uniformly, the stirring time during the mixing process is not less than 30 minutes.

[0077] It is understandable that in order to kill microorganisms in the raw materials, extend the shelf life of the product and ensure food safety, after the above step 1) and before step 2), the first raw material liquid is further heated to 93-97°C for sterilization, and the sterilization time is 300-360 seconds. After the sterilization treatment is completed, the temperature can be lowered to 28-32°C for standby use.

[0078] The present invention does not impose any specific restrictions on the selection of raw milk, thickener, sweetener and stabilizer in step 2), and the above raw materials can be selected from the range of raw materials mentioned above.

[0079] In step 2), heating the raw milk to above 50°C can not only accelerate the dissolution of other raw materials, but also make the mixing process more uniform, so that the properties of the yogurt layer in the double-skin yogurt product are more stable, and the characteristics of not easily separating water and gelling are more prominent, thereby further improving the storage resistance of the double-skin yogurt product.

[0080] The present invention does not specifically limit the order of mixing the thickener, sweetener, stabilizer and raw milk in step 2). The above three components can be mixed with the raw milk separately, or any two of the three components can be pre-mixed and then mixed with the raw milk. In one embodiment, the above three components are pre-mixed and then mixed with the raw milk.

[0081] It is understandable that in order to ensure that the microbial activity in the fermentation bacteria is not destroyed, after mixing the thickener, sweetener, stabilizer with the raw milk at a temperature above 50°C, the mixture should be cooled to room temperature before adding the leavening agent.

[0082] In step 3), the second raw material liquid is first loaded into a container for selling double-skin yogurt, and then the first raw material liquid is loaded into the container containing the second raw material liquid. Since the first raw material liquid has a higher fat content than the second raw material liquid and a lower density than the second raw material liquid, the first raw material liquid floats on the second raw material liquid. Here, the first raw material liquid should be filled gently to avoid mixing the first raw material liquid and the second raw material liquid, which affects the formation of the milk skin layer.

[0083] The third raw material liquid is composed of the first raw material liquid and the second raw material liquid, wherein the first raw material liquid is located above the second raw material liquid, and at least part of the lower surface of the first raw material liquid is in contact with at least part of the upper surface of the second raw material liquid. The third raw material liquid is placed in a container for selling double-skin yogurt and fermented. During the fermentation process, the fermentation agent contained in the second raw material liquid converts the lactose in the second raw material liquid into lactic acid, so that the second raw material liquid is converted into a yogurt layer; the first raw material liquid is always located above the second raw material liquid to form a milk skin layer. Therefore, the fourth raw material liquid is fermented to obtain a product, double-skin yogurt.

[0084] The present invention does not impose any specific restrictions on the temperature of the fermentation process, as long as the second raw material liquid is reasonably converted into a yogurt layer through fermentation. In one embodiment, the fermentation temperature is 28-32°C.

[0085] Furthermore, the acidity of the yogurt layer can be monitored in real time during the fermentation process. When the acidity of the yogurt layer reaches 70-75°F, the fermentation process can be terminated.

[0086] Furthermore, in order to break the fat globules in the raw milk into smaller pieces and evenly suspend them in the liquid, thereby improving the stability of the yogurt layer, after step 2), the second raw liquid is further subjected to homogenization. The treatment temperature of the homogenization treatment is 65-70° C., the pressure of the first stage of the homogenization treatment is 40 bar, and the pressure of the second stage is 180 bar.

[0087] It is understandable that, in order to kill the microorganisms in the raw materials and extend the shelf life of the product, after the above step 2) and before step 3), the second raw material liquid is further heated to 93-97°C for sterilization, and the sterilization time is 300-360 seconds. After the sterilization treatment is completed, the temperature can be lowered to 28-32°C for standby use.

[0088] Furthermore, in order to make the first raw material liquid solidify into the milk skin layer faster, in one embodiment, after completing step 4), the obtained product is also stored at 2-6°C.

[0089] The double-skin yogurt provided by the present invention will be further introduced in detail below in conjunction with specific embodiments.

[0090] Example 1-1:

[0091] The first stock solution was prepared using the following raw materials:

[0092] raw material Addition amount (kg) Source of raw materials Cream 668.6 Nestle white sugar 40 Beijing Sugar Co., Ltd. Cocoa Butter 290 Tianshun Mono- and di-glycerides of fatty acids 1.4 Danisco

[0093] Prepare the second stock solution using the following materials:

[0094]

[0095]

[0096] The preparation of double-skin yogurt comprises the following steps:

[0097] 1) heating the cream to 52° C., adding cocoa butter, white sugar and mono- and di-glycerol fatty acid esters, and stirring for 30 minutes to obtain a first raw material liquid;

[0098] 2) sterilizing the first raw material liquid at a temperature of 95° C. and a time of 300 seconds;

[0099] 3) cooling the sterilized first raw material liquid to 30° C. for standby use;

[0100] 4) dry-mix white sugar, gelatin, pectin and hydroxypropyl distarch phosphate, add into milk preheated to 53° C., and stir for 30 minutes to obtain a second raw material liquid;

[0101] 5) The second raw material liquid is subjected to homogenization and sterilization treatment in sequence, and after the treatment is completed, the temperature is cooled to 28-32°C for standby use. The treatment temperature of the homogenization treatment is 70°C, the pressure of the first stage of the homogenization treatment is 40 bar, and the pressure of the second stage is 180 bar; the treatment temperature of the sterilization treatment is 93-97°C, and the treatment time of the sterilization treatment is 300-360s;

[0102] 6) adding thermophilic Streptococcus and bulgaricus to the second raw material liquid to obtain a third raw material liquid;

[0103] 7) Firstly, the third raw material liquid is filled, and then the container containing the third raw material liquid is filled with the first raw material liquid so that the first raw material liquid is located above the third raw material liquid to obtain a fourth raw material liquid, wherein the mass ratio of the first raw material liquid to the third raw material liquid is 1:999;

[0104] 8) The fourth raw material liquid is fermented at 28-32° C., and the fermentation is terminated when the acidity of the yogurt layer reaches 70° T to obtain a double-skin yogurt product A1-1.

[0105] Example 1-2

[0106] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:499, and a double-skin yogurt product A1-2 is obtained.

[0107] Examples 1-3

[0108] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:332.3, and a double-skin yogurt product A1-3 is obtained.

[0109] Examples 1-4

[0110] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:249, and a double-skin yogurt product A1-4 is obtained.

[0111] Examples 1-5

[0112] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:199, and a double-skin yogurt product A1-5 is obtained.

[0113] Examples 1-6

[0114] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:165.7, and a double-skin yogurt product A1-6 is obtained.

[0115] Examples 1-7

[0116] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:141.9, and a double-skin yogurt product A1-7 is obtained.

[0117] Examples 1-8

[0118] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:124, and a double-skin yogurt product A1-8 is obtained.

[0119] Examples 1-9

[0120] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:110.1, and a double-skin yogurt product A1-9 is obtained.

[0121] Examples 1-10

[0122] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:99, and a double-skin yogurt product A1-10 is obtained.

[0123] Embodiment 1-11

[0124] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:89.9, and a double-skin yogurt product A1-11 is obtained.

[0125] Examples 1-12

[0126] This embodiment is basically the same as embodiment 1-1, except that the mass ratio of the first raw material liquid to the third raw material liquid is 1:82.3, and a double-skin yogurt product A1-12 is obtained.

[0127] Example 2-1

[0128] This embodiment is basically the same as Embodiment 1-5, except that:

[0129] The first stock solution was prepared using the following raw materials:

[0130] raw material Addition amount (kg) Source of raw materials Cream 635 Nestle white sugar 40 Beijing Sugar Co., Ltd. Cocoa Butter 323.6 Tianshun Mono- and di-glycerides of fatty acids 1.4 Danisco

[0131] Prepare the second stock solution using the following materials:

[0132] raw material Addition amount (kg) Source of raw materials raw milk 953.7 Yili Company Ranch white sugar 40 Beijing Sugar Co., Ltd. gelatin 3 Rossello Pectin 0.3 CP Kelco Hydroxypropyl distarch phosphate 3 Taylor & Lyle Streptococcus thermophilus <![CDATA[1×10 9 cfu / g]]> Danisco, Yo-mix 300 Lactobacillus bulgaricus <![CDATA[2×10 9 cfu / g]]> Danisco, Yo-mix 300

[0133] The double-skin yogurt product A2-1 was obtained.

[0134] Example 2-2

[0135] This embodiment is basically the same as embodiment 2-1, except that the following raw materials are used to prepare the first raw material liquid:

[0136] raw material Addition amount (kg) Source of raw materials Cream 593.6 Nestle white sugar 40 Beijing Sugar Co., Ltd. Cocoa Butter 365 Tianshun Mono- and di-glycerides of fatty acids 1.4 Danisco

[0137] The double-skin yogurt product A2-2 was obtained.

[0138] Example 2-3

[0139] This embodiment is basically the same as embodiment 2-1, except that:

[0140] The first stock solution was prepared using the following raw materials:

[0141] raw material Addition amount (kg) Source of raw materials Cream 590.6 Nestle white sugar 40 Beijing Sugar Co., Ltd. Cocoa Butter 368 Tianshun Mono- and di-glycerides of fatty acids 1.4 Danisco

[0142] The double-skin yogurt product A2-3 was obtained.

[0143] Example 3-1

[0144] This embodiment is basically the same as Embodiment 1-5, except that:

[0145] Prepare the second stock solution using the following materials:

[0146]

[0147]

[0148] The double-skin yogurt product A3-1 was obtained.

[0149] Example 3-2

[0150] This embodiment is basically the same as Embodiment 1-5, except that:

[0151] Prepare the second stock solution using the following materials:

[0152] raw material Addition amount (kg) Source of raw materials raw milk 956.9 Yili Company Ranch white sugar 40 Beijing Sugar Co., Ltd. gelatin 2 Rossello Pectin 0.1 CP Kelco Hydroxypropyl distarch phosphate 1 Taylor & Lyle Streptococcus thermophilus <![CDATA[1×10 9 cfu / g]]> Danisco, Yo-mix 300 Lactobacillus bulgaricus <![CDATA[2×10 9 cfu / g]]> Danisco, Yo-mix 300

[0153] The double-skin yogurt product A3-2 was obtained.

[0154] Example 3-3

[0155] This embodiment is basically the same as Embodiment 1-5, except that:

[0156] Prepare the second stock solution using the following materials:

[0157]

[0158]

[0159] The double-skin yogurt product A3-3 was obtained.

[0160] Embodiment 3-4

[0161] This embodiment is basically the same as Embodiment 1-5, except that:

[0162] Prepare the second stock solution using the following materials:

[0163] raw material Addition amount (kg) Source of raw materials raw milk 955.2 Yili Company Ranch white sugar 40 Beijing Sugar Co., Ltd. gelatin 2.5 Rossello Pectin 0.3 CP Kelco Hydroxypropyl distarch phosphate 2 Taylor & Lyle Streptococcus thermophilus <![CDATA[1×10 9 cfu / g]]> Danisco, Yo-mix 300 Lactobacillus bulgaricus <![CDATA[2×10 9 cfu / g]]> Danisco, Yo-mix 300

[0164] The double-skin yogurt product A3-4 was obtained.

[0165] Embodiment 3-5

[0166] This embodiment is basically the same as Embodiment 1-5, except that:

[0167] Prepare the second stock solution using the following materials:

[0168] raw material Addition amount (kg) Source of raw materials raw milk 949.1 Yili Company Ranch white sugar 40 Beijing Sugar Co., Ltd. gelatin 8.5 Rossello Pectin 0.4 CP Kelco Hydroxypropyl distarch phosphate 2 Taylor & Lyle Streptococcus thermophilus <![CDATA[1×10 9 cfu / g]]> Danisco, Yo-mix 300 Lactobacillus bulgaricus <![CDATA[2×10 9 cfu / g]]> Danisco, Yo-mix 300

[0169] The double-skin yogurt product A3-5 was obtained.

[0170] Example 4-1

[0171] This embodiment is basically the same as Embodiment 1-5, except that:

[0172] The first raw material liquid was prepared using the same raw materials as in Example 2-2.

[0173] The second raw material liquid was prepared using the same raw materials as in Example 3-1.

[0174] The double-skin yogurt product A4-1 was obtained.

[0175] Example 4-2

[0176] This embodiment is basically the same as embodiment 4-1, except that:

[0177] The second raw material liquid was prepared using the same raw materials as in Example 3-2.

[0178] The double-skin yogurt product A4-2 was obtained.

[0179] Example 4-3

[0180] This embodiment is basically the same as embodiment 4-1, except that:

[0181] The second raw material solution was prepared using the same raw materials as in Example 3-3.

[0182] The double-skin yogurt product A4-3 was obtained.

[0183] Example 4-4

[0184] This embodiment is basically the same as embodiment 4-1, except that:

[0185] The second raw material solution was prepared using the same raw materials as in Example 3-4.

[0186] The double-skin yogurt product A4-4 was obtained.

[0187] Embodiment 4-5

[0188] This embodiment is basically the same as embodiment 4-1, except that:

[0189] The second raw material solution was prepared using the same raw materials as in Example 3-5.

[0190] The double-skin yogurt product A4-5 was obtained.

[0191] Comparative Example 1-1

[0192] This comparative example is basically the same as Example 1, except that:

[0193] The first stock solution was prepared using the following raw materials:

[0194] raw material Addition amount (kg) Source of raw materials Cream 908.8 Nestle white sugar 40 Beijing Sugar Co., Ltd. Cocoa Butter 50 Tianshun Mono- and di-glycerides of fatty acids 1.2 Danisco

[0195] The double-skin yogurt product B1-1 was obtained.

[0196] Comparative Example 1-2

[0197] This comparative example is basically the same as Example 1, except that:

[0198] The first stock solution was prepared using the following raw materials:

[0199] raw material Addition amount (kg) Source of raw materials Cream 858.8 Nestle white sugar 40 Beijing Sugar Co., Ltd. Cocoa Butter 100 Tianshun Mono- and di-glycerides of fatty acids 1.2 Danisco

[0200] The double-skin yogurt product B1-2 was obtained.

[0201] Comparative Examples 1-3

[0202] This comparative example is basically the same as Example 1, except that:

[0203] The first stock solution was prepared using the following raw materials:

[0204] raw material Addition amount (kg) Source of raw materials Cream 783.8 Nestle white sugar 40 Beijing Sugar Co., Ltd. Cocoa Butter 175 Tianshun Mono- and di-glycerides of fatty acids 1.2 Danisco

[0205] The double-skin yogurt product B1-3 was obtained.

[0206] Comparative Examples 1-4

[0207] This comparative example is basically the same as Example 1, except that:

[0208] The first stock solution was prepared using the following raw materials:

[0209] raw material Addition amount (kg) Source of raw materials Cream 708.8 Nestle white sugar 40 Beijing Sugar Co., Ltd. Cocoa Butter 250 Tianshun Mono- and di-glycerides of fatty acids 1.2 Danisco

[0210] The double-skin yogurt product B1-4 was obtained.

[0211] Test example

[0212] 1. Test the hardness of the yogurt layer and the milk skin layer of products A1-5, products A2-1 to A2-3, products A3-1 to A3-5, products A4-1 to A4-5, product A5-1, and products B1-1 to B1-4 using the following method:

[0213] The test was conducted using a TPA texture analyzer with a TA11 / 1000 standard cylindrical probe. The parameters were set as follows:

[0214] Pre-measurement speed: 1.00mm / s;

[0215] Test speed: 1.00mm / s;

[0216] Post-measurement speed: 1.00mm / s;

[0217] Punching depth: 15.000mm;

[0218] Time: 10.00s;

[0219] Trigger force: 0.1g;

[0220] Each product was tested three times and the average value was taken to obtain the hardness test result.

[0221] The measurement results are shown in Table 1:

[0222] Table 1 Statistics of the hardness of the milk skin layer and yogurt layer and the test results

[0223]

[0224]

[0225] 2. Observe the hardness and morphology of the milk cortex of products B1-1, B1-2, B1-3, B1-4, A2-1, A2-2 and A2-3. The results are recorded in Table 2:

[0226] Table 2 Observation table of milk skin hardness and morphology

[0227] Product Number Milk skin hardness (g) Milk cortex physical state B1-1 30 The milk skin is soft and fat, with a rough surface and wrinkled edges. B1-2 85 The milk skin is soft and fat, with a rough surface and wrinkled edges. B1-3 120 The milk skin is soft and fat, with a rough surface and wrinkled edges. B1-4 172 The milk skin is soft and fat, with a rough surface and wrinkled edges. A2-1 230 The surface of the milk skin is smooth, the edges are smooth and wrinkle-free A2-2 275 The surface of the milk skin is smooth, the edges are smooth and wrinkle-free A2-3 310 The surface of the milk skin is smooth, the edges are smooth and wrinkle-free, but the texture is too hard

[0228] From the data in Table 2, it can be seen that the hardness of the milk skin is more suitable at 200-300g.

[0229] 3. Experiments were conducted on the taste differences of products A3-1 to A3-5 and products A4-1 to A4-5 due to the hardness difference between the milk skin layer and the yogurt layer. The experimental results are recorded in Table 3:

[0230] Table 3 Taste difference experimental data statistics

[0231]

[0232]

[0233] It can be seen from the data in Table 3 that when the hardness of the milk skin layer is 200-250g, the hardness of the yogurt layer is 150-200g, and the hardness difference between the milk skin layer and the yogurt layer is 45-55g, the double-skin yogurt has a better taste.

[0234] 4. Select products A1-5 and A3-1 and conduct stability observation for 30 days under retail storage conditions. Record the observation data in Table 4.

[0235] Table 4 Stability observation data

[0236] time Products A1-5 Product A3-1 Day 0 No water or glue precipitation No water or glue precipitation 3 days No water or glue precipitation No water or glue precipitation 6 days No water or glue precipitation No water or glue precipitation 9 days No water or glue precipitation No water or glue precipitation 12 days No water or glue precipitation No water or glue precipitation 15 days No water or glue precipitation No water or glue precipitation 18 days No water or glue precipitation Water and gel precipitation occurs 21 days No water or glue precipitation Water and gel precipitation occurs 24 days No water or glue precipitation Water and gel precipitation occurs 27 days No water or glue precipitation Water and gel precipitation occurs 30 days No water or glue precipitation Water and gel precipitation occurs

[0237] It can be seen from the data in Table 4 that compared with product A3-1 obtained by preparing the yogurt layer using different raw material ratios, the yogurt layer of product A1-5 has higher stability.

[0238] 5. Observe the thickness of the milk skin layer and the spreading state of the milk skin layer in the container for 12 products, namely, products A1-1 to A1-12. The observation results are recorded in Table 5:

[0239] Table 5 Observation table of milk skin thickness and spreading state

[0240]

[0241]

[0242] It can be seen from the data in Table 5 that when the mass ratio of the milk skin layer to the yogurt layer is not less than 1:499, the milk skin layer can cover the entire surface of the container, and the double-skin yogurt has a better appearance.

[0243] 6. For products A1-5, A2-1, A3-4, B1-1, B1-2, B1-3, and B1-4, 60 professional evaluators (male to female ratio of 1:1) were selected to evaluate the products based on color, texture, internal structure, taste, and smell. The evaluation criteria are shown in Table 6, and the full score for each indicator is 10. The results of the sensory evaluation are recorded in Table 7 based on the average of the 60 people's scores:

[0244] Table 6 Evaluation criteria for milk yogurt

[0245]

[0246] Table 7 Sensory evaluation results

[0247]

[0248]

[0249] It can be seen from the data in Table 7 that, compared with the product prepared in the comparative example, the product prepared in the embodiment of the present invention has better performance in all dimensions.

[0250] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A double-skin yogurt, characterized in that: The double-skin yogurt consists of a milk skin layer and a yogurt layer, wherein the milk skin layer is located above the yogurt layer, and the hardness of the milk skin layer is not less than 200g.

2. The double-skin yogurt according to claim 1, characterized in that: The hardness of the milk skin layer is 200-250g, the hardness of the yogurt layer is 150-200g, and the hardness difference between the milk skin layer and the yogurt layer is 45-55g.

3. The double-skin yogurt according to claim 1 or 2, characterized in that: The milk skin layer is prepared from raw materials including cream and cocoa butter, wherein the cream accounts for no less than 61.2% of the total mass percentage of the raw materials, and the cocoa butter accounts for no less than 28.4% of the total mass percentage of the raw materials.

4. The double-skin yogurt according to claim 3, characterized in that: The raw materials used for preparing the milk skin layer include, by mass percentage, 3-6% of white sugar, 0.8-1.6% of mono- and di-glycerol fatty acid esters, 61.2-64% of light cream, and 28.4-35% of cocoa butter.

5. The double-skin yogurt according to claim 4, characterized in that: The milk skin layer is obtained by a preparation method comprising the following steps: 1) heating the cream to a temperature not lower than 50° C. to obtain hot cream; 2) adding granulated sugar, mono- and di-glycerol fatty acid esters and cocoa butter to the hot cream and stirring to obtain the milk skin layer.

6. The double-skin yogurt according to any one of claims 1 to 5, characterized in that: The raw materials for preparing the yogurt layer include, by mass percentage, 92.97-96.37% of raw milk, 3-6% of sweetener, 0.4-0.8% of thickener, 0.23-0.53% of stabilizer, and also include a leavening agent.

7. The double-skin yogurt according to any one of claims 1 to 6, characterized in that: The mass ratio of the milk skin layer to the yogurt layer is 1:99-1:

499.

8. A method for preparing double-skin yogurt, for preparing the double-skin yogurt according to any one of claims 1 to 7, characterized in that: The steps include: 1) mixing cream, cocoa butter, a sweetener and an emulsifier to obtain a first raw material liquid; 2) Using the first raw material liquid to perform a filling process on the system including the yogurt layer to obtain the double-skin yogurt.

9. A method for preparing double-skin yogurt, for preparing the double-skin yogurt according to any one of claims 1 to 7, characterized in that: The steps include: 1) mixing cream, cocoa butter, a sweetener and an emulsifier to obtain a first raw material liquid; 2) mixing a thickener, a sweetener, a stabilizer and raw milk at a temperature above 50° C. and then adding a starter to obtain a second raw material liquid; 3) sequentially filling the second raw material liquid and the first raw material liquid so that the first raw material liquid is located above the second raw material liquid to obtain a third raw material liquid; 4) fermenting the third raw material liquid to obtain the double-skin yogurt.

10. The preparation method according to claim 8 or 9, characterized in that: The method also includes coagulating the first raw material at 2-6° C. to obtain a milk skin layer.

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