Texture adjustment of sour cream and preparation method thereof

Abstract

The present invention relates to the field of food technology, and specifically provides a method for adjusting the texture of sour cream and a method for preparing the same. The texture adjustment method provided by the present invention comprises subjecting the curd obtained after acidification to steam direct injection sterilization or tubular ultra-high temperature sterilization under certain conditions and aseptic homogenization under specific conditions. Using the texture adjustment method provided by the present invention, during the preparation of sour cream, the sterilization and aseptic homogenization methods are optimized for the curd after acidification, achieving a whey-free process and adjusting the texture of the curd without adding thickeners or stabilizers, thereby obtaining a sour cream having a certain hardness, spreadability, and whippability, and having a good texture.

Description

Technical Field

[0001] The invention relates to the technical field of food, and specifically provides a texture adjustment method of sour cream and a preparation method thereof. Background Art

[0002] Acidified cream is widely used in the food industry, such as baking, cakes, cooking, and cakes, due to its mild creamy flavor, light sour taste, lack of bitterness, smooth creamy texture and certain spreadability.

[0003] The production process of sour cream includes acidification, which can be divided into fermentation acidification and exogenous acidification. Specifically, exogenous acidification involves heating cream to 80-95°C, adding a certain amount of organic acid such as tartaric acid, lactic acid, or citric acid to acidify the cream, and then placing the resulting curds into a cloth bag to drain and remove the whey to produce sour cream. Fermentation acidification involves homogenizing and pasteurizing standardized cream, then adding a starter culture or rennet to bring the cream to a certain pH and curd it. After heat treatment to terminate fermentation, the resulting curds are placed into a cloth bag to remove the whey to produce sour cream.

[0004] Traditional production methods, whether exogenous or fermentative, require whey removal, a process that typically takes 20 hours. This makes continuous production of acidified cream difficult, and it also presents challenges such as low product yield and long production times. To improve the efficiency of acidified cream production, with the maturation of membrane separation technology, there are reports of reducing production time by removing the whey from the curds obtained after exogenous or fermentative acidification through centrifugation or membrane filtration. However, these methods still suffer from intermittent production, low yields (whey removal rates range from 40% to 80%), and the inability to achieve continuous production.

[0005] In order to improve production yield and even avoid whey discharge, achieve continuous production, and ensure that the spreadability and texture of acidified cream are comparable to those obtained by traditional production processes, some acidified cream products on the market use certain thickeners or stabilizers (such as locust bean gum, carrageenan, gellan gum, etc.) to enhance the texture (hardness, viscosity, etc.) and reduce whey precipitation to obtain a smooth and stable acidified cream. However, the thickeners or stabilizers will appear in the ingredient list, which does not meet the current product requirements for clean labels.

[0006] For example, the inventors previously proposed using a protein concentrate obtained by concentrating skim milk to a protein concentration of 15-25% as a protein raw material and mixing it with cream. The solution is then preheated to a certain temperature and acidified by adding an acidity regulator after preheating. This method can achieve a high yield of curd, without the need for whey drainage, by simply sterilizing and homogenizing it through ultra-high temperature sterilization. However, the use of a protein concentrate as a protein raw material in combination with cream still has certain limitations. Specifically, the protein in sour cream not only provides protein but also contributes to the formation of textural properties such as hardness. Currently, approximately 82% of clean-label sour cream products on the market have a fat content greater than 35% and a protein content greater than 4%. For products with a protein content below 4%, the fat content needs to be increased to at least 40% to achieve the desired texture (hardness, spreadability, viscosity, etc.). This indicates that different sour creams with different protein contents have different mechanisms for forming the textural properties of the curd. In particular, sour creams with protein contents below 4% have a greater difficulty in developing a texture. Therefore, a method for adjusting the texture of soured cream that avoids whey drainage and the addition of additional additives, while also being suitable for clean label applications, is urgently needed. Summary of the Invention

[0007] As mentioned above, the existing technology mainly considers obtaining sour cream with satisfactory hardness and spreadability by optimizing raw materials and thickeners, while little attention is paid to how to adjust the texture of curd by adjusting the preparation process to obtain sour cream with good texture.

[0008] The present invention finds that the texture of acidified curd can be regulated by designing and manipulating sterilization and homogenization parameters, thereby obtaining sour cream with different textural properties such as hardness. Specifically, the hardness of the sour cream is distributed in the range of 0.35N to 1.3N.

[0009] Therefore, a first aspect of the present invention provides a method for adjusting the texture of sour cream, comprising: mixing, pretreating, and acidifying raw materials to obtain curd having a pH value of 5.0 to 6.5, wherein the curd is further subjected to high-temperature sterilization and aseptic homogenization;

[0010] The high temperature sterilization includes sterilizing the curd at a temperature of 121-143° C. by direct steam injection for 2-10 seconds, or sterilizing the curd at a temperature of 110-121° C. by tubular sterilization for 2-10 seconds.

[0011] The aseptic homogenization temperature is 60-85° C., and the homogenization pressure is 20-40 MPa.

[0012] The textural properties of acidified cream products are primarily determined by the different interactions between fat and protein. In acidified cream systems, fat primarily exists in the form of fat globules, while protein aggregates and, to a certain extent, encapsulates the fat globules. Therefore, optimizing the fat-to-protein ratio can adjust the textural properties of acidified cream. Generally speaking, increasing the fat content results in a higher hardness of the final product, while decreasing the fat content results in a lower hardness and improved spreadability. While sterilization and homogenization are conventional processes in acidified cream systems, the present inventors have discovered that, under specific sterilization (equipment and parameters) and homogenization conditions, the degree of protein aggregation and encapsulation of fat globules can be optimized, thereby achieving texture optimization of the acidified cream. The texture optimization method proposed in this invention, which optimizes process conditions, differs from methods that optimize raw material ratios. This method, without whey removal, is applicable to a wider range of raw materials and ratios for producing clean-label acidified cream.

[0013] Preferably, according to the method for adjusting the texture of the sour cream provided by the present invention, the curd is sterilized by direct steam injection at an ultra-high temperature of 121-140°C for 6-10 seconds and then aseptically homogenized; or, the curd is sterilized by tubular ultra-high temperature of 110-121°C for 6-10 seconds and then aseptically homogenized.

[0014] The adjustment of curd texture in the present invention depends on the coordination of sterilization equipment parameters and aseptic homogenization parameters. Preferably, in the method for adjusting the texture of sour cream provided by the present invention, the aseptic homogenization temperature is 75-85°C and the homogenization pressure is 20-40 MPa.

[0015] As previously mentioned, adjusting the texture of low-protein sour cream (less than 4%) is more difficult due to its low protein content. Experiments have shown that the texture adjustment method of the present invention is applicable not only to high-protein sour cream, but also to low-protein sour cream. When adjusting the texture of low-protein curd, there is no need to drain whey during the production process.

[0016] In other words, the present invention has discovered that, in the process of preparing sour cream with a low protein content, by designing and combining a specific sterilization method and an aseptic homogenization method for the acidified curd, the hardness, spreadability and other textures of the finished sour cream can be controlled and regulated without draining the whey or adding additional additives.

[0017] Therefore, by adopting the texture adjustment method of the present invention, when preparing sour cream using raw materials with a low protein content, whey drainage is not required, and the texture of conventional sour cream, such as hardness and spreadability, can still be achieved without adding a thickener. The obtained sour cream meets the clean label standard.

[0018] Preferably, according to the method for adjusting the texture of the sour cream provided by the present invention, the fat content of the curd is 35-45% by mass, and the protein content is 2-7% by mass; further preferably, the fat content of the curd is 35-45% by mass, and the protein content is 2-4% by mass; more preferably, the fat content of the curd is 35-40% by mass, and the protein content is 2-4%.

[0019] In the present invention, when the protein content in the curd is any value between 2% and 7%, and the fat content in the curd is 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44% or 45%, the texture adjustment method of the present invention can be adopted to achieve the hardness, spreadability and other textures of conventional sour cream without draining whey, without adding a thickener, and the obtained sour cream meets the clean label standard.

[0020] In a second aspect, the present invention further provides a method for preparing sour cream, comprising: preparing the sour cream using the method for adjusting the texture of sour cream.

[0021] Preferably, according to the method for preparing sour cream provided by the present invention, the acidification includes: exogenous acidification and fermentation acidification.

[0022] The exogenous acidification includes obtaining curd by adding organic acid.

[0023] The fermentation and acidification comprises: obtaining curd by inoculating Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris.

[0024] Preferably, the method for preparing sour cream according to the present invention further comprises: adding a protein concentrate to the cream and then acidifying it. As described above, the texture adjustment method provided by the present invention can adjust the texture of curd of any recipe. Therefore, when preparing sour cream using the above texture adjustment method, the protein concentrate can be added to the cream and then acidified to obtain a sour cream that meets the requirements of a specific protein content, hardness, and spreadability.

[0025] Preferably, the method for preparing sour cream provided by the present invention comprises: mixing cream and protein raw materials, preheating, exogenous acidification, high-temperature sterilization, aseptic homogenization, filling and maturation.

[0026] Alternatively, preferably, the method for preparing sour cream provided by the present invention comprises: mixing cream and protein raw materials, sterilizing, fermenting and acidifying, demulsifying, preheating, high-temperature sterilizing, aseptic homogenizing, filling and maturating.

[0027] In the above method, when mixing the cream and the protein raw material, the process of adjusting the protein and fat content (for example, heating, centrifugation, adding protein concentrate) so that the protein and fat content of the mixed cream reaches the set content can also be called standardization.

[0028] In a third aspect, the present invention provides a sour cream prepared by the above preparation method.

[0029] The sour cream provided by the invention has a fat content of 35-45% and a protein content of 2-7%.

[0030] The beneficial effects of the present invention are:

[0031] The invention omits the whey drainage process by optimizing the sterilization equipment, sterilization conditions and aseptic homogenization conditions of the curd. Moreover, under the optimized process conditions, the texture of the curd with various protein contents can be adjusted, thereby obtaining sour cream with good textures such as hardness and whipping properties.

[0032] When preparing sour cream using the texture adjustment method, whey drainage is not required throughout the production process, resulting in a production yield of substantially 100%. Therefore, the sour cream of the present invention is prepared in a short time and can be produced continuously. The resulting sour cream has the same hardness, spreadability, and viscosity as conventionally produced soured cream. Furthermore, the sour cream obtained by the present invention has a low water separation rate, is free of graininess, and has a clean ingredient list. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a laser confocal image of the sour cream prepared when the pH value of the curd is 4.5.

[0034] Figure 2 This is a laser confocal image of the sour cream prepared when the pH value of the curd is 5.5.

[0035] Figure 3 This is a laser confocal image of the sour cream prepared when the pH value of the curd is 6.5. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] The present invention includes the following test indicators and test methods for the product:

[0038] (1) Microstructure of fat protein: The observation method is laser confocal microscopy. The specific method includes: using biological dye labeling method and combining laser confocal microscopy to observe the microstructural changes of fat globule aggregation in gel samples of different crystalline fats, the distribution and aggregation state of fat protein. The specific conditions are: (1) Co-staining of protein and fat in the sample with fast green and Nile red. For example: add 40 μL of 1 mg / mL fast green solution and 10 μL of 1 mg / mL Nile red ethanol solution to 4 mL sample, mix and stain in the dark for more than 2 hours, take 10 μL of the stained sample and drop it on a clean slide to make it evenly distributed on the slide surface. (2) Laser confocal microscopy: The laser confocal microscopy conditions are Ar / Kr laser source, 100x objective lens, fluorescence mode, and the excitation light source wavelengths are 633 nm and 560 nm respectively. Among them, the fat in sour cream is stained red and the protein is stained green. The test images reflect the size and spatial state of fat and protein under different treatment conditions.

[0039] (2) Hardness, spreadability, and viscosity: After the samples were stored in a refrigerator at 4°C for 12 h, the hardness, spreadability, and viscosity of the samples were measured using a TA-XTPlus physical property tester. Pre-test speed: 8.0 mm / s; during-test speed: 3 mm / s; after-test speed: 10 mm / s; test distance: 13 mm; test time: 5 s; probe type: cylindrical probe (35 mm diameter). All samples were tested three times.

[0040] (3) Whey precipitation amount: Take 30 g of sour cream sample and place it at room temperature for 1 hour. Centrifuge it at 20℃ and 3000 r / min for 30 minutes. Collect the whey in the lower layer and express it as the mass of whey precipitated per 100 g of sample (%).

[0041] (4) Whipping characteristics of acidified cream: Mix acidified cream and light cream in a 1:1 ratio and whip at high speed for 60 seconds. Observe the degree of expansion. Scores are given on a scale of 0 to 10, with higher scores indicating greater expansion.

[0042] (5) Product yield = (finished product quantity / raw material quantity) × 100%; the raw material quantity is the sum of all raw materials used: including cream, various protein raw materials or protein liquid, etc.

[0043] (6) Flavor and taste: The tasters are professionally trained personnel, and the number of tasters is no less than 10. Take 20g of sample and place it in a tasting cup with a lid. The taster uses a small spoon to weigh an appropriate amount of sour cream and observe its color, surface state and fluidity; smell the odor; and finally put it in the mouth and taste its fineness, granularity, freshness, and milky aroma. The evaluation criteria are shown in Table 1.

[0044] Table 1

[0045]

[0046] Example 1 Preparation of low-protein sour cream by exogenous acidification

[0047] This embodiment provides a method for preparing sour cream by exogenous acidification, the steps of which are as follows:

[0048] (1) Using raw milk as raw material, a cream separator was used at a temperature of 50-70°C and a speed of 7000 rpm to produce cream with a fat content of 50% and skimmed milk.

[0049] Among them, the fat content in skim milk is less than 0.2%.

[0050] (2) Skim milk at 45±2℃ was treated with a 10kDa rolled ultrafiltration membrane with a concentration ratio of 6 to produce a high-protein concentrate with a protein concentration of 17%.

[0051] (3) The cream is mixed with the protein concentrate, and the fat content of the mixture is 45% and the protein content is 3%.

[0052] (4) Preheating: Preheat the mixed cream to 75±2℃.

[0053] (5) Acidification: A 10% citric acid aqueous solution was added to the mixture by spraying, and the mixture was continuously stirred at a speed of 50 rpm to obtain curd, and the pH value of the curd reached 5.5.

[0054] (6) The acidified curd is sterilized by direct steam injection at ultra-high temperature at 140°C for 8 seconds.

[0055] (7) Aseptic homogenization: The curd sterilized in step (6) is cooled to 75°C and aseptically homogenized at a homogenization condition of 30 MPa.

[0056] (8) Aseptic filling: Cool the homogenized curd to 45°C for aseptic filling.

[0057] (9) Maturation: The filled curd is matured at 2-8°C for 12 hours and then refrigerated to obtain sour cream.

[0058] The sour cream obtained in this example has a fat content of 45%, a protein content of 3%, and a pH value of 5.5.

[0059] Example 2 Preparation of low-protein sour cream by exogenous acidification

[0060] This embodiment provides a method for preparing sour cream by exogenous acidification. The difference between this embodiment and Example 1 is that:

[0061] Step (6) of this embodiment: the acidified curd is sterilized by ultra-high temperature sterilization in a tubular manner: 121°C for 8s.

[0062] (7) Aseptic homogenization: The curd sterilized in step (6) is cooled to 75°C and aseptically homogenized at a homogenization condition of 20 MPa.

[0063] The resulting sour cream had a fat content of 45%, a protein content of 3% and a pH of 5.5.

[0064] Example 3 Preparation of low-protein sour cream by fermentation and acidification

[0065] This embodiment provides a method for preparing sour cream by fermentation and acidification, the steps of which are as follows:

[0066] (1) Using raw milk as raw material, a cream separator was used at a temperature of 50-70°C and a rotation speed of 7000 rpm to produce cream with a fat content of 50% and skim milk. The fat content of the skim milk was less than 0.2%.

[0067] (2) Skim milk at 45±2℃ was treated with a 10kDa rolled ultrafiltration membrane with a concentration ratio of 6 to produce a high-protein concentrate with a protein concentration of 17%.

[0068] (3) Standardization: The cream is mixed with the protein concentrate to obtain a mixture having a fat content of 45% and a protein content of 2%.

[0069] (4) The mixture obtained in step (3) is pasteurized (95°C, 60s).

[0070] (5) The sterilized cream was cooled to 28°C, inoculated with a certain amount of Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris, and fermented for 15 h until the pH value reached 5.5.

[0071] (6) Stir to break the emulsion and heat to 75°C.

[0072] (7) The acidified material is sterilized by direct steam injection at ultra-high temperature: sterilization at 140°C for 8 seconds.

[0073] (8) Aseptic homogenization: The sterilized curd is cooled to 75°C and aseptically homogenized at a homogenization condition of 40 MPa.

[0074] (9) Aseptic filling: Cool the homogenized curd to 45°C for aseptic filling.

[0075] (10) Maturation: The filled curd is matured at 2-8°C for 12 hours and then refrigerated.

[0076] The resulting sour cream had a fat content of 45%, a protein content of 2% and a pH of 5.5.

[0077] Example 4 Preparation of Low-Protein Sour Cream by Fermentation and Acidification

[0078] This embodiment provides a method for preparing sour cream by fermentation and acidification. The difference between this embodiment and Example 3 is that:

[0079] Step (7) of this embodiment: the acidified material is sterilized by ultra-high temperature sterilization in a tube-in-tube manner: 121°C, 8s.

[0080] (8) Aseptic homogenization: The sterilized curd is cooled to 75°C and aseptically homogenized at a homogenization condition of 20 MPa.

[0081] The resulting sour cream had a fat content of 45%, a protein content of 2% and a pH of 5.5.

[0082] Example 5 Preparation of high protein sour cream by exogenous acidification

[0083] This embodiment provides a method for preparing exogenous acidified cream, the steps of which are as follows:

[0084] (1) Using raw milk as raw material, a cream separator was used at a temperature of 50-70°C and a rotation speed of 7000 rpm to produce cream with a fat content of 50% and skim milk. The fat content of the skim milk was less than 0.2%.

[0085] (2) Skim milk at 45±2℃ was treated with a 10kDa rolled ultrafiltration membrane with a concentration ratio of 6 to produce a high-protein concentrate with a protein concentration of 17%.

[0086] (3) The cream was mixed with the ultrafiltered high protein concentrate so that the fat content of the mixed cream was 37% and the protein content was 5%.

[0087] (4) Preheating: Preheat the mixed cream to 75±2℃.

[0088] (5) Acidification: A 10% citric acid aqueous solution was added to the mixture by spraying, and the mixture was continuously stirred at a speed of 50 rpm to obtain curd, and the pH value of the curd reached 5.5.

[0089] (6) The acidified material is sterilized by direct steam injection at ultra-high temperature: sterilization at 140°C for 8 seconds.

[0090] (7) Aseptic homogenization: The curd sterilized in step (6) is cooled to 75°C and aseptically homogenized at a homogenization condition of 30 MPa.

[0091] (8) Aseptic filling: Cool the homogenized curd to 45°C for aseptic filling.

[0092] (9) Maturation: The filled curd is matured at 2-8°C for 12 hours and then refrigerated to obtain the sour cream.

[0093] The resulting sour cream had a fat content of 37%, a protein content of 5% and a pH of 5.5.

[0094] Example 6 Preparation of high-protein sour cream by fermentation and acidification

[0095] This example provides a method for preparing sour cream by fermentation and acidification. The difference from Example 5 is that in this example, cream with a fat content of 37% and a protein content of 5% is pasteurized (95° C., 60 s).

[0096] The sterilized cream was cooled to 28°C and inoculated with a certain amount of Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris. Fermented for 15 hours until the pH reached 5.5. Stirred to break the emulsion and heated to 75°C to prepare the acidified material.

[0097] The other steps were the same as those in Example 5. The sour cream obtained in this example had a fat content of 37%, a protein content of 5%, and a pH value of 5.5.

[0098] Example 7 Different degrees of acidification

[0099] The method for preparing the sour cream used in this example is the same as that in Example 1. This example explores the pH values of the curd during acidification in step (5) to reach 4.5, 5.5, and 6.5, respectively. Among them, the pH value of the curd is 5.5, which is the pH value of Example 1.

[0100] The distribution of fat and protein in sour cream under different curd pH conditions is shown in the laser confocal microscopy. Figure 1-3 , red represents fat particles; green represents protein particles. Figure 1 In the middle, fat globules vary in size and diameter, and proteins aggregate; Figure 2 The number of medium and large fat globules decreases, protein aggregation decreases, and some proteins are wrapped on the surface of fat globules; Figure 3 The size of fat globules tends to be consistent, and more protein wraps around the surface of the fat globules.

[0101] Laser confocal microscopy analysis of sour cream at different pH conditions revealed that at pH values of 5.5 and 6.5, whey protein aggregation decreased, the size of fat globules became more uniform, and whey protein coated the surface of the fat globules, reducing their tendency to aggregate and stabilizing the system. Texture testing also revealed that at a pH of 4.5, the hardness, spreadability, and viscosity of sour cream decreased significantly.

[0102] Comparative Example 1

[0103] The difference between this comparative example and Example 2 is that in this comparative example, step (6): the acidified curd is subjected to a tubular ultra-high temperature sterilization condition that is different.

[0104] In the comparative example treatment group 1 (Comparative Example 1-1), the shell and tube ultrahigh temperature sterilization conditions used were 137°C, 4s; in the treatment group 2 (Comparative Example 1-2), the shell and tube ultrahigh temperature sterilization conditions used were 137°C, 6s.

[0105] The experiment failed, the material was not formed, and the texture requirements were not met.

[0106] Comparative Example 2

[0107] The difference between this comparative example and Example 1 is that in step (7) of this comparative example, the curd sterilized in step (6) is cooled to 75° C. and the aseptic homogenization condition is 14 MPa.

[0108] The experiment failed, the material was not formed, and the texture requirements were not met.

[0109] Comparative Example 3

[0110] The difference between this comparative example and Example 2 is that, in step (7) of this comparative example, the curd sterilized in step (6) is cooled to 75°C and the aseptic homogenization condition is 14 MPa.

[0111] The experiment failed, the material was not formed, and the texture requirements were not met.

[0112] Comparative Example 4

[0113] The difference between this comparative example and Example 1 is that the time used for sterilization in step (6) in this comparative example is 1.5 s.

[0114] The experiment failed, the material did not take shape, and the product hygiene conditions did not meet the standards.

[0115] Experimental Example 1

[0116] This experimental example tested the hardness, spreadability, viscosity, swelling degree, whey precipitation amount and yield of the product of the embodiment, and the results are shown in Table 2 below.

[0117] Table 2

[0118]

[0119] Experimental Example 2

[0120] This experimental example tested the flavor and taste of the products of the examples. Since comparative examples 1, 2, 3, and 4 failed to meet the molding requirements and comparative example 4 failed to meet the sanitary conditions, no flavor and taste evaluation was performed. The results are shown in Table 3.

[0121] Table 3

[0122]

[0123] It can be seen from the test results of the above embodiments and comparative examples that:

[0124] By using specific sterilization equipment and setting specific parameters, the texture of sour cream products with different protein contents can be made equivalent to that of traditional sour cream, and even the hardness and spreadability can be further improved. At the same time, the protein supplementation process can be avoided, and the ingredient cost can be reduced. This achieves texture characteristics that are equal to or better than those of traditional sour cream products without draining whey and increasing production yield.

[0125] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing sour cream, characterized in that: include: The raw materials are mixed, pretreated, and acidified to obtain curd having a pH value of 5.5 to 6.5, and the curd is further sterilized at high temperature and homogenized aseptically; The curd has a fat content of 35-45% and a protein content of 2-3% by mass; The high temperature sterilization includes sterilizing the curd at a temperature of 121 to 143° C. by direct steam injection for 2 to 10 seconds, or sterilizing the curd at a temperature of 110 to 121° C. by tubular sterilization for 2 to 10 seconds. When using the steam direct injection ultra-high temperature sterilization method, the sterile homogenization temperature is 60-85°C and the homogenization pressure is 30-40MPa; When the tubular ultra-high temperature sterilization method is adopted, the temperature of the aseptic homogenization is 60-85° C. and the homogenization pressure is 20 MPa.

2. The method for preparing sour cream according to claim 1, wherein: The curd is sterilized by direct steam injection at ultra-high temperature of 121-140° C. for 6-10 seconds and then aseptically homogenized; Alternatively, the curd is sterilized in a tubular ultra-high temperature sterilization process at 110-121° C. for 6-10 seconds and then aseptically homogenized.

3. The method for preparing sour cream according to claim 1, wherein: The temperature of the sterile homogenization is 75-85°C.

4. The method for preparing sour cream according to claim 1, wherein: The acidification includes: exogenous acidification and fermentation acidification; The exogenous acidification includes: obtaining curd by adding organic acid; The fermentation and acidification comprises: obtaining curd by inoculating Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris.

5. The method for preparing sour cream according to claim 4, characterized in that: Also includes: The acidification is carried out after the addition of protein concentrate to the cream.

6. The method for preparing sour cream according to claim 4 or 5, characterized in that: include: Cream and protein raw materials are mixed, pre-treated, acidified, pasteurized, aseptically homogenized and filled.

7. A sour cream, characterized in that The compound is prepared by the preparation method according to any one of claims 1 to 6.

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