Cream cheese and preparation method thereof

Abstract

The invention provides cream cheese and a preparation method thereof, and belongs to the technical field of dairy product processing. According to the method, firstly, raw milk is subjected to degreasing and membrane filtration concentration, the concentration multiple is controlled to be 1.5-4, the lactose content of the concentrated solution is precisely regulated and controlled to be 3-6.5% through washing filtration, and the raw milk concentrated solution rich in casein (accounting for 85-95% of total protein) is obtained. Then, mixing the concentrated solution with single cream, white granulated sugar and the like, homogenizing, sterilizing, inoculating a leavening agent and chymosin, fermenting, refrigerating and demulsifying to obtain a finished product. According to the invention, nutrition waste and environmental pollution caused by discharge of whey in a traditional process are fundamentally avoided through membrane filtration pretreatment, and meanwhile, the problems of pink feeling and peculiar smell caused by addition of milk protein powder are solved; the obtained product is pure and rich in flavor, fine and smooth in texture, simple and efficient in process and suitable for large-scale production.

Description

Technical Field

[0001] This invention patent belongs to the field of dairy processing technology, specifically relating to a cream cheese and its preparation method. Background Technology

[0002] Cream cheese, a popular soft fresh cheese, is prized for its delicate texture and rich, creamy aroma. However, its traditional production process has long faced challenges in terms of resource waste and quality control.

[0003] First, the traditional cream cheese production process involves multiple steps, including fermentation and whey removal, making it complex. To simplify the process and avoid whey removal, current technologies often involve directly adding milk protein powder to increase the product's solids content. However, the addition of exogenous milk protein powder may introduce an unpleasant powdery texture and milky odor, affecting the cheese's natural, pure flavor. Furthermore, insufficient hydration of the milk protein powder may affect the cream cheese's structure, resulting in a coarser texture and a loss of the silky smoothness characteristic of traditional cream cheese.

[0004] Furthermore, precise control of lactose content in products is challenging, regardless of whether the process uses traditional methods or adds protein powder. Excessive lactose not only affects flavor but can also increase osmotic pressure, inhibit the activity of fermentation bacteria, and pose health risks to lactose-intolerant consumers.

[0005] Therefore, there is an urgent need in this field for a new cream cheese production process that can fundamentally avoid whey discharge, maximize the retention of natural milk proteins, precisely control lactose content, eliminate powderiness, and enhance flavor purity. Membrane filtration technology, as a highly efficient physical separation method, offers a potential solution to this goal. Summary of the Invention

[0006] To address at least one of the aforementioned problems, this invention provides a novel cheese-making process that utilizes a pre-membrane filtration concentration process. This process physically separates water and lactose to achieve concentration while retaining a high proportion of casein in the final cheese product. The process also preserves as much of the natural nutrients of the original milk as possible, resulting in a purer and richer cheese flavor. Compared to traditional cheese-making processes, this new process is simpler, reduces complex production steps and equipment investment, and helps improve production efficiency.

[0007] To achieve the above objectives, the present invention is specifically implemented through the following technical solution:

[0008] In a first aspect, this application provides a concentrated milk comprising protein and lactose, wherein the protein comprises 6.8-10.1% by mass and the lactose comprises 4-6% by mass.

[0009] On the other hand, this application provides a method for preparing concentrated milk, the method comprising the step of concentrating raw milk to obtain concentrated milk as described above.

[0010] On the other hand, this application provides a method for preparing a cream cheese base, the method comprising the steps of mixing concentrated milk as described above or concentrated milk prepared by any of the methods described above with light cream and white sugar, and homogenizing to obtain the base; optionally, the method further comprises sterilization and / or cooling steps.

[0011] On the other hand, this application provides a method for preparing cream cheese curd, the method comprising the step of fermenting a base material prepared by the above method under suitable fermentation conditions using a starter culture and rennet to obtain curd.

[0012] On the other hand, this application provides a method for preparing cream cheese, characterized in that the method includes the step of breaking the curd prepared by the above method to prepare cream cheese.

[0013] Beneficial effects:

[0014] This invention fundamentally avoids the nutrient waste and environmental pollution caused by whey discharge in traditional processes through membrane filtration pretreatment, while solving the problems of powdery texture and off-flavor caused by adding milk protein powder; the resulting product has a pure and rich flavor and delicate texture, and the process is simple and efficient, suitable for large-scale production. Attached Figure Description

[0015] Figure 1 This is a sample image from Example 1;

[0016] Figure 2 This is the sample for Comparative Example 1. Detailed Implementation

[0017] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings. These embodiments are only for illustrating this application and are not intended to limit the scope of the invention.

[0018] First, the traditional cream cheese production process involves multiple steps, including fermentation and whey removal, making it complex. To simplify the process and avoid whey removal, current technologies often involve directly adding milk protein powder to increase the product's solids content. However, the addition of exogenous milk protein powder may introduce an unpleasant powdery texture and milky odor, affecting the cheese's natural, pure flavor. Furthermore, insufficient hydration of the milk protein powder may affect the cream cheese's structure, resulting in a coarser texture and a loss of the silky smoothness characteristic of traditional cream cheese.

[0019] Furthermore, precise control of lactose content in products is challenging, regardless of whether the process uses traditional methods or adds protein powder. Excessive lactose not only affects flavor but can also increase osmotic pressure, inhibit the activity of fermentation bacteria, and pose health risks to lactose-intolerant consumers.

[0020] To address these issues, in a first aspect, this application provides a concentrated milk comprising protein and lactose, wherein the protein comprises 6.8-10.1% by mass and the lactose comprises 4-6% by mass.

[0021] In a specific embodiment, the protein includes casein. In a specific embodiment, the casein mass percentage is 6.4-9.1% based on the mass percentage of the concentrated milk. In a specific embodiment, the casein protein accounts for 90-95% of the total protein mass.

[0022] The lactose content in the concentrate should be controlled at 4-6%. During microfiltration concentration, not only is the protein content concentrated, but lactose is also concentrated, resulting in a high lactose content in the concentrate. However, excessively high lactose content and osmotic pressure are detrimental to the growth of microorganisms during subsequent fermentation and increase the risk of gastrointestinal discomfort for consumers. Therefore, controlling the lactose content helps fermentation proceed smoothly and enhances the sensory experience of cream cheese.

[0023] In specific embodiments, the protein content is 6.8%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, and 10.1% by weight percentage of concentrated milk.

[0024] In specific embodiments, the lactose content is 4.0%, 4.5%, 5.0%, 5.5%, and 6.0% by weight of concentrated milk.

[0025] In specific embodiments, the total solids percentage by weight of concentrated milk is 8%, 8.5%, 9.0%, 9.5%, 10.0%, 12.8%, 13%, 13.5%, 14%, 14.5%, 15.5%, 16.0%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19.0%, 19.5%, and 20%.

[0026] For example, the concentrated milk comprises protein and lactose, with the protein accounting for 6.8% of the total mass of the concentrated milk and the lactose accounting for 4.0% of the total mass of the concentrated milk.

[0027] For example, the concentrated milk comprises protein and lactose, wherein the protein accounts for 10.1% by mass and the lactose accounts for 6% by mass of the concentrated milk.

[0028] In a specific embodiment, the protein contains casein.

[0029] In a specific embodiment, the casein content, calculated as a percentage of concentrated milk mass, is 6.4% and 9.1%.

[0030] In a specific embodiment, the casein content accounts for 90-95% of the protein mass.

[0031] In a specific embodiment, the casein content accounts for 90-94% of the protein mass.

[0032] In a specific embodiment, the concentrated milk is obtained solely through concentration.

[0033] In a specific embodiment, the concentrated milk is obtained from raw milk through concentration only. In a specific embodiment, the raw milk is selected from skim milk.

[0034] Controlling the protein content of the concentrate within this range is crucial for balancing the final cheese yield and texture characteristics: too low a protein content will lead to decreased yield and a loose texture, while too high a protein content will affect the flowability of the concentrate and create difficulties for subsequent homogenization and standardization operations. In particular, limiting the casein percentage (and casein / whey protein ratio) to the aforementioned high range is essential for ensuring the efficiency of the subsequent curdling process and the formation of a robust, continuous casein network structure. This is a decisive prerequisite for obtaining a firm, high-quality cheese product. Within this range, the lactose content provides a precise and sufficient source of fermentable sugars for the subsequent fermentation stage, ensuring stable kinetics of lactic acid bacteria fermentation and harmonious flavor development, avoiding fermentation stagnation due to insufficient sugar sources or excessive acidity due to excessive sugars. Within this optimized range, the total solids content provides an ideal material basis for the entire process, ensuring the effective execution of subsequent processes (such as fermentation and curdling) and directly determining the basic solids level and full-bodied texture of the finished cheese.

[0035] To address the aforementioned issues, this invention provides a method for preparing cream cheese, comprising a method for preparing concentrated milk, a method for preparing the base material of cream cheese, and a method for preparing the curd of cream cheese. Utilizing a pre-filtration concentration process, water and lactose are separated through physical methods to achieve concentration, while simultaneously retaining a high proportion of casein in the final cheese product. This process also preserves as much of the natural nutrients of the original milk as possible, resulting in a purer and richer flavor in the cheese. Compared to traditional cheese-making processes, this new process is simpler, reduces complex production steps and equipment investment, and helps improve production efficiency.

[0036] To address the aforementioned issues, the present invention provides a method for preparing concentrated milk, the method comprising the step of concentrating raw milk to obtain the concentrated milk described above.

[0037] In a specific embodiment, the concentration is selected from centrifugal separation, membrane concentration, and vacuum drying concentration. In a specific embodiment, the membrane concentration is selected from microfiltration membrane or ultrafiltration membrane. In a specific embodiment, the concentration factor of the membrane concentration is 2-3 times. In a specific embodiment, the temperature of the membrane concentration is 8-12°C. In a specific embodiment, the temperature includes the feed temperature. In a specific embodiment, the transmembrane pressure of the membrane concentration is 1.4-1.8 bar.

[0038] Membrane filtration concentrate has significant advantages over the protein powder addition process. While direct protein powder addition maintains the basic structure in terms of texture, its flavor and overall evaluation are significantly lower than in all examples. This proves that even with the same protein content, exogenously added, dried protein powder introduces an unavoidable "powdery" feel and non-natural flavor substances, severely damaging the pure milky aroma and overall flavor harmony that cream cheese should possess. The membrane filtration concentrate used in this invention, however, preserves the natural structure and function of milk proteins to the greatest extent, achieving a perfect combination of texture and flavor.

[0039] When the concentration ratio is lower than 2-3 times (e.g., Comparative Example 4), the total score is only 84 points. Due to the low total solids content, the concentrated milk protein and total solids content are both low, resulting in a thin texture and bland flavor in the finished product. This proves the necessity of the lower limit of the concentration ratio range in this invention.

[0040] Furthermore, the method also includes a step of retaining casein and / or washing and filtering the concentrated raw milk; preferably, the casein and / or washing and filtering step is performed after the concentration step. For example, after retaining casein and / or washing and filtering, the mass percentage of the protein is 6.8-10.1%, the mass percentage of casein is 6.4-9.1%, the mass percentage of lactose is 4-6%, and the casein content accounts for 90-95% of the protein mass. Precise control of lactose content through washing and filtering is a key prerequisite for ensuring fermentation kinetics and flavor purity: failure to wash and filtering and excessively high lactose content result in poor performance across all sensory indicators. Excessively high lactose content leads to osmotic pressure imbalance in the material, significantly inhibiting the fermentation activity and metabolic pathways of lactic acid bacteria, resulting in incomplete fermentation, insufficient acidity generation, and a lack of characteristic flavor compounds. Simultaneously, excessive residual lactose can also lead to uneven sweetness in the product and pose a risk of lactose intolerance. The results demonstrate that precisely controlling the mass percentage of lactose within the range of 4.0%-6% (e.g., 4%-6%) through the washing and filtration step is an indispensable process step for providing the optimal carbon source environment for subsequent fermentation processes, ensuring normal flavor formation, and guaranteeing the safety of the product for consumption.

[0041] Casein is the main protein in cheese curdling, forming a three-dimensional gel network. Insufficient casein directly leads to weak curd strength and a sparse, broken protein network. This manifests as a loose, inelastic texture and a rough mouthfeel, failing to achieve the delicate, smooth texture expected of cream cheese. It also weakens the product's ability to carry and slowly release flavor compounds. A low casein ratio results in a lower overall evaluation. This indicates that optimizing membrane processing parameters to increase and stabilize the casein content in the total protein range at 90%-95% is a decisive factor in obtaining a firm, pure, and rich-tasting cheese product.

[0042] To address the aforementioned problems, the present invention provides a method for preparing a base material for cream cheese. The method includes mixing concentrated milk as described above, or concentrated milk prepared by any of the methods described above, with light cream and granulated sugar, followed by homogenization to obtain the base material. In a specific embodiment, the method further includes sterilization and / or cooling steps.

[0043] In a specific embodiment, the sterilization includes sterilization at 90-95°C for 15 seconds to 10 minutes;

[0044] In a specific embodiment, the cooling refers to cooling to 30-35°C.

[0045] To address the aforementioned issues, the present invention provides a method for preparing curd for cream cheese, the method comprising fermenting a base material prepared by the above method under suitable fermentation conditions using a starter culture and rennet to prepare curd.

[0046] In a specific embodiment, the fermentation temperature is 30-35°C. For example, it may be 30°C, 31°C, 32°C, 33°C, 34°C, or 35°C.

[0047] To address the aforementioned problems, the present invention provides a method for preparing cream cheese, the method comprising the step of demulsifying the curd prepared by the above method to prepare cream cheese.

[0048] In a specific embodiment, the demulsification includes stirring. In a specific embodiment, the stirring speed is 25-75 r / min. In a specific embodiment, the stirring speed is 50 r / min.

[0049] To address the aforementioned problems, the present invention provides a method for preparing cream cheese, the method comprising:

[0050] (1) The step of concentrating raw milk to obtain concentrated milk, wherein the concentrated milk comprises protein and lactose, and the mass percentage of protein is 6.8-10.1%, the mass percentage of lactose is 4-6%, and the mass percentage of casein is 6.4-9.1% by weight of the concentrated milk;

[0051] (2) The concentrated milk is mixed with light cream and white sugar and homogenized to obtain the base material;

[0052] (3) Sterilize and cool the base material;

[0053] (4) Ferment the cooled substrate using a starter culture and rennet to obtain curd;

[0054] (5) Perform post-ripening and / or demulsification on the curd.

[0055] In a specific embodiment, the raw milk is selected from skim milk.

[0056] In specific embodiments, the protein content is 6.8%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, and 10.1% by weight of concentrated milk.

[0057] In specific embodiments, the lactose content is 4.0%, 4.5%, 5.0%, 5.5%, and 6.0% by weight of concentrated milk.

[0058] In specific embodiments, the total solids percentage by weight of concentrated milk is 8%, 8.5%, 9.0%, 9.5%, 10.0%, 12.8%, 13%, 13.5%, 14%, 14.5%, 15.5%, 16.0%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19.0%, 19.5%, and 20%.

[0059] When the concentration factor is set to 2-3, the feed temperature of the skim milk should be maintained in a low-temperature range of 8-12°C during membrane concentration, and the transmembrane pressure of the membrane separation should be maintained at 1.4-1.8 bar. Controlling an appropriate concentration factor range can balance separation efficiency and process economy. Too low a factor will increase the load on subsequent processes, while too high a factor will easily accelerate membrane fouling and affect the stability of long-term operation.

[0060] The concentrate obtained in the previous step is washed and filtered to control the lactose content to 4-6% by mass. During microfiltration concentration, not only protein but also lactose is concentrated, resulting in a higher lactose content in the concentrate. However, excessively high lactose content and osmotic pressure are detrimental to microbial growth during subsequent fermentation and increase the risk of gastrointestinal discomfort for consumers. Therefore, controlling the lactose content helps ensure smooth fermentation and enhances the sensory experience of the cream cheese. In a specific embodiment, the mixing is accompanied by stirring for 10-25 minutes.

[0061] In specific embodiments, the stirring time is 10 min, 15 min, or 25 min.

[0062] In a specific embodiment, the stirring temperature is 50℃-60℃.

[0063] In a specific embodiment, the stirring temperature is 50°C or 60°C.

[0064] In a specific embodiment, the pressure of the homogenization is 10-20 MPa.

[0065] In specific embodiments, the homogenization pressure is 10 MPa, 15 MPa, or 20 MPa.

[0066] In a specific embodiment, the homogenization temperature is 60℃-70℃.

[0067] In a specific embodiment, the homogenization temperature is 60°C or 70°C.

[0068] In a specific embodiment, the sterilization temperature of the sterilization method is 90-95℃, and the sterilization time is 15s-10min.

[0069] In a specific embodiment, the concentrated milk comprises 36% and 47% of the total mass.

[0070] In a specific embodiment, the mass of the light cream is 50% or 60% by total mass.

[0071] In a specific embodiment, the mass of the white sugar is 3% or 4% by total mass.

[0072] In a specific embodiment, the inoculation temperature of the fermentation agent is 30-35℃.

[0073] In a specific embodiment, the inoculation temperature of the fermenting agent is 35°C.

[0074] In a specific embodiment, the fermenting agent and rennet are added to the base material and then stirred.

[0075] In a specific embodiment, the stirring time is 1-3 minutes.

[0076] In a specific embodiment, the fermentation time is 12-20 hours.

[0077] In a specific embodiment, based on the total mass of the cream cheese base, the concentrated milk accounts for 36%-47% by mass, the heavy cream accounts for 50%-60% by mass, and the granulated sugar accounts for 3%-4% by mass. In a specific embodiment, the heavy cream includes fat, and based on the total mass of the heavy cream, the fat accounts for 36-40% by mass.

[0078] In a specific embodiment, the ratio of the fermentation agent to the substrate is 4-5 DCU:100kg; in a specific embodiment, the ratio of the rennet to the substrate is 0.1-0.3 g:100kg.

[0079] In a specific embodiment, t is a ton.

[0080] In a specific embodiment, the homogenization pressure is 0-20 MPa, and in a specific embodiment, the homogenization pressure is 20 MPa; in a specific embodiment, stirring is performed before homogenization, the stirring temperature is 50°C, the stirring speed is 100-200 r / min, and the stirring time is 1-15 min; in a specific embodiment, the stirring time is 5 min or 15 min; in a specific embodiment, the stirring speed is 150 r / min.

[0081] In a specific embodiment, the pressure of the homogenization process is 10-20 MPa. In another specific embodiment, stirring is performed before homogenization, and the stirring speed is 100-200 r / min.

[0082] In a specific embodiment, the homogenization temperature is 50-90°C. In a specific embodiment, the homogenization temperature is 70°C.

[0083] In a specific embodiment, the fermentation includes fermentation to a pH of 4.0-5.6; preferably, the pH is 4.8;

[0084] In a specific embodiment, the demulsification process further includes cooling; in a specific embodiment, the cooling includes low-temperature refrigeration; more preferably, the low temperature is 0-8°C; more preferably, 4°C;

[0085] In a specific embodiment, the sterilization temperature is 90-100℃, and the sterilization time is 5-15 minutes;

[0086] In a specific embodiment, stirring is performed before fermentation. In a specific embodiment, the stirring time is 1-3 minutes; the stirring speed is 25-75 r / min. In a specific embodiment, the stirring speed is 50 r / min.

[0087] In a specific embodiment, the fermenting agent is selected from Lactococcus lactis.

[0088] In a specific embodiment, the starter culture was purchased from Danisco, product number MA14. The viable count of the lactic acid bacteria was ≥10⁻⁶. 8 CFU / g.

[0089] In a specific embodiment, the rennet was purchased from Beijing Duoate Biotechnology Co., Ltd.

[0090] In a specific embodiment, the refrigeration time at 4°C is 36 hours.

[0091] In a specific embodiment, the method includes the following:

[0092] (1) A concentrated retentate solution with adjusted lactose and casein content was obtained by membrane filtration;

[0093] (2) Weigh out the light cream and white sugar, add them to the raw milk concentrate, stir, homogenize, sterilize, and cool;

[0094] (3) Inoculate with lactic acid bacteria starter and rennet, stir well, and ferment;

[0095] (4) After the fermented base material is placed in a 4°C refrigerator, it is taken out, broken and stirred, and sealed to obtain the cream cheese.

[0096] In a specific embodiment, the detailed parameters in step (1) are as described above.

[0097] In a specific embodiment, in step (2), the stirring time is 1-5 min; the homogenization pressure is 0-20 MPa. The sterilization temperature of the sterilization method is 90-95℃, and the sterilization time is 15 s-10 min.

[0098] In a specific embodiment, in step (3), the inoculation temperature is 30-35℃ to provide a suitable environment for the growth of thermophilic lactic acid bacteria starter; the stirring time is 1-3 min; and the fermentation time is 12-20 h.

[0099] In a specific embodiment, the refrigeration time in step (4) is 12-24 hours.

[0100] The key components in the raw milk concentrate obtained after the aforementioned treatment are as follows: protein content of 3.8-10.1%, of which casein accounts for 90-95% of the total protein; lactose content of 4-6%; and total solids content of 8-20%. Controlling the protein content of the concentrate within this range is crucial for balancing the final cheese product yield and texture characteristics: too low a protein content will lead to decreased yield and loose texture, while too high a protein content will affect the flowability of the concentrate and create difficulties for subsequent homogenization and standardization operations. In particular, limiting the casein percentage (and casein / whey protein ratio) to the aforementioned high range is essential for ensuring the efficiency of the subsequent coagulation process and the formation of a robust and continuous casein network structure, which is a decisive prerequisite for obtaining a firm texture and excellent taste cheese product. Within this range, the lactose content provides a precise and sufficient source of fermentable sugar for the subsequent fermentation stage, ensuring the kinetic stability of lactic acid bacteria fermentation and the coordinated generation of flavor, avoiding fermentation stagnation due to insufficient sugar source or excessive acidity due to excessive sugar source. The total solids content within this optimized range provides an ideal material basis for the entire process, ensuring the effective execution of subsequent processes (such as fermentation and curdling) and directly determining the basic solids level and full-bodied taste of the finished cheese.

[0101] In a specific embodiment, the cream cheese comprises protein, fat, and lactose, wherein the protein comprises 3.2%-5.4% by weight, the fat comprises 20%-24% by weight, and the lactose comprises 2.2%-3.4% by weight. In a specific embodiment, the cream cheese contains casein, wherein the casein comprises 2.9%-4.8% by weight. In a specific embodiment, the cream cheese contains whey protein, wherein the mass ratio of casein to whey protein is 89:11-92:8.

[0102] In specific embodiments, the protein content is 3.2%, 3.8%, 4.4%, and 5.4% by weight of cream cheese.

[0103] In a specific embodiment, the fat percentage by weight is 20%, 21%, 22%, 23%, or 24% based on the weight percentage of cream cheese.

[0104] In a specific embodiment, the lactose content is 2.2%, 2.5%, 2.9%, and 3.4% by weight of cream cheese.

[0105] In specific embodiments, the casein content is 2.9%, 3.5%, 3.9%, and 4.8% by weight of cream cheese.

[0106] In a specific embodiment, the mass ratio of casein to whey protein, based on the percentage of cream cheese, is 89:11, 91:9, or 92:8.

[0107] For example, the cream cheese comprises, by weight percentage, protein, fat, lactose, and casein, wherein the protein accounts for 3.8% by weight, the fat accounts for 20% by weight, the lactose accounts for 2.5% by weight, and the casein accounts for 3.5% by weight. The cream cheese contains casein and whey protein in a weight ratio of 92:8.

[0108] For example, the cream cheese comprises, by weight percentage, protein, fat, lactose, and casein, wherein the protein accounts for 3.2% by weight, the fat accounts for 24% by weight, the lactose accounts for 2.2% by weight, and the casein accounts for 2.9% by weight. The cream cheese contains casein and whey protein in a weight ratio of 91:9.

[0109] For example, the cream cheese comprises, by weight percentage, protein, fat, lactose, and casein, wherein the protein accounts for 5.4% by weight, the fat accounts for 20% by weight, the lactose accounts for 3.4% by weight, and the casein accounts for 4.8% by weight. The cream cheese contains casein and whey protein in a weight ratio of 89:11.

[0110] For example, the cream cheese comprises, by weight percentage, protein, fat, lactose, and casein, wherein the protein accounts for 4.4% by weight, the fat accounts for 24% by weight, the lactose accounts for 2.9% by weight, and the casein accounts for 3.9% by weight. The cream cheese contains casein and whey protein in a weight ratio of 89:11.

[0111] The membrane filtration concentrate used in this invention retains the natural structure and function of milk proteins to the greatest extent, achieving a perfect combination of texture and flavor.

[0112] Cheese is produced using pressure-driven filtration technology and liquid pre-made cheese technology. This process concentrates milk into a concentrate, removing lactose and some whey protein, which is equivalent to concentrating casein. Then, it is directly made into cheese through acidification and curdling, without removing whey.

[0113] The membrane-filtered concentrated cream cheese and its preparation method provided by this invention have the following advantages:

[0114] (1) The product does not have a "powdery feel" caused by the addition of protein powder, and it is fully fermented with a rich flavor;

[0115] (2) The final product is rich in casein and retains the natural nutrients of the original milk, making the cheese taste purer and richer;

[0116] (3) The pre-concentration process enables controllable whey discharge, reducing resource waste and nutrient loss caused by traditional whey discharge processes;

[0117] (4) The process steps have been simplified, reducing complex production steps and equipment investment, lowering production costs and improving production efficiency. This makes the cheese process a more economical and practical method for dairy production.

[0118] All raw materials and reagents used in the following examples were purchased commercially. The fermentation agents used are all made from... The starter culture MA14 purchased from Danisco contains ≥10 live lactic acid bacteria. 8 CFU / g. Rennet was purchased from Beijing Du'ate. Biotechnology company.

[0119] Example 1

[0120] The raw material formula for a type of concentrated cream cheese before membrane filtration is shown in Table 1:

[0121] Table 1

[0122]

[0123] Preparation method:

[0124] 1) The raw skim milk is concentrated by membrane filtration to a concentration factor of 2. The skim milk is kept at 12°C and the transmembrane pressure is 1.4 bar. By removing casein and washing the filter, the casein content is reduced to 95% of the total protein and the lactose content is reduced to 4%, resulting in raw concentrated milk (also known as membrane filtration concentrate). By mass percentage of raw concentrated milk, it contains 6.8% protein, 6.4% casein and 4.0% lactose.

[0125] 2) Mix the raw material concentrated milk (also known as membrane filtration concentrate) with light cream and white sugar in the proportions mentioned above according to Table 1, heat to 50℃ and stir at 150r / min for 10min; heat to 60℃ and homogenize at 20Mpa to obtain the base material;

[0126] 3) Sterilize the base material at 95°C for 10 minutes, then cool it to 35°C;

[0127] 4) Inoculate with starter culture and rennet according to Table 1, stir at 50 r / min for 1 min, and ferment until pH=4.8 to obtain curd;

[0128] 5) After the fermentation of the curd is broken by stirring at 50 r / min, it is placed in a refrigerator at 4℃ for 36 h to obtain the finished product (Example 1 Cream Cheese).

[0129] The cream cheese obtained in this embodiment contains 3.8% protein, 3.5% casein, 20% fat, and 2.5% lactose, where the percentages are based on the mass percentage of the cream cheese. The casein:whey protein ratio is 92:8.

[0130] Method for detecting protein content: According to GB 5009.5—2016 Method I.

[0131] The method for detecting casein content is based on GB 31638-2016.

[0132] The method for detecting lactose content is based on Method IV of GB 5009.8-2023.

[0133] Method for detecting fat content: According to GB 5009.6—2016, Method III.

[0134] Example 2

[0135] The raw material formula for a type of concentrated cream cheese before membrane filtration is shown in Table 2:

[0136] Table 2

[0137]

[0138] Preparation method:

[0139] 1) The raw skim milk is concentrated by membrane filtration to a concentration factor of 2. The skim milk is kept at 12°C and the transmembrane pressure is 1.4 bar. By removing casein and washing the filter, the casein content is reduced to 95% of the total protein and the lactose content is reduced to 4%, resulting in raw concentrated milk (also known as membrane filtration concentrate). By mass percentage of raw concentrated milk, it contains 6.8% protein, 6.4% casein and 4.0% lactose.

[0140] 2) Mix the raw material concentrated milk (also known as membrane filtration concentrate) with light cream and white sugar in the proportions mentioned above according to Table 2, heat to 60℃ and stir at 150r / min for 15min; heat to 70℃ and homogenize at 10Mpa to obtain the base material;

[0141] 3) Sterilize the base material at 90°C for 10 minutes, then cool it to 35°C;

[0142] 4) Inoculate the starter culture and rennet according to Table 2, stir at 50 r / min for 1 min, and ferment until pH=4.8 to obtain curd;

[0143] 5) After the fermented curd is broken by stirring at 50 r / min, it is placed in a refrigerator at 4℃ for 36 h to obtain the finished product (Example 2 Cream Cheese).

[0144] The cream cheese obtained in this embodiment contains 3.2% protein, 2.9% casein, 24% fat, and 2.2% lactose, where the percentages are based on the mass percentage of the cream cheese. The casein:whey protein ratio is 91:9.

[0145] The methods for detecting protein content, casein content, lactose content, and fat content are as shown in Example 1.

[0146] Example 3

[0147] The raw material formula for a type of concentrated cream cheese before membrane filtration is shown in Table 3:

[0148] Table 3

[0149]

[0150] Preparation method:

[0151] 1) The raw skim milk is concentrated by membrane filtration to a concentration factor of 3. The skim milk is kept at 8°C and the transmembrane pressure is 1.8 bar. By removing casein and washing the filter, the casein content is reduced to 90% of the total protein and the lactose content is reduced to 6%, resulting in raw concentrated milk (also known as membrane filtration concentrate). By mass percentage of raw concentrated milk, it contains 10.1% protein, 9.1% casein and 6.0% lactose.

[0152] 2) Mix the raw material concentrated milk (also known as membrane filtration concentrate) with light cream and white sugar in the proportions mentioned above according to Table 3, heat to 50℃ and stir at 150r / min for 25min; heat to 60℃ and homogenize at 15Mpa to obtain the base material;

[0153] 3) Sterilize the base material at 95°C for 10 minutes, then cool it to 35°C;

[0154] 4) Inoculate the starter culture and rennet according to Table 3, stir at 50 r / min for 1 min, and ferment until pH=4.8 to obtain curd;

[0155] 5) After the fermentation of the curd is broken by stirring at 50 r / min, it is placed in a refrigerator at 4℃ for 36 h to obtain the finished product (Example 3 Cream Cheese).

[0156] The cream cheese obtained in this embodiment contains 5.4% protein, 4.8% casein, 20% fat, and 3.4% lactose, where the percentages are based on the mass percentage of the cream cheese. The casein:whey protein ratio is 89:11.

[0157] The methods for detecting protein content, casein content, lactose content, and fat content are as shown in Example 1.

[0158] Example 4

[0159] The raw material formula for a type of concentrated cream cheese before membrane filtration is shown in Table 4:

[0160] Table 4

[0161]

[0162] Preparation method:

[0163] 1) The raw skim milk is concentrated by membrane filtration to a concentration factor of 3. The skim milk is kept at 8°C and the transmembrane pressure is 1.8 bar. By removing casein and washing the filter, the casein content is reduced to 90% of the total protein and the lactose content is reduced to 6%, resulting in raw concentrated milk (also known as membrane filtration concentrate). By mass percentage of raw concentrated milk, it contains 10.1% protein, 9.1% casein and 6.0% lactose.

[0164] 2) Mix the raw material concentrated milk (also known as membrane filtration concentrate) with light cream and white sugar in the proportions mentioned above according to Table 4, heat to 50℃ and stir at 150r / min for 15min; heat to 70℃ and homogenize at 20Mpa to obtain the base material;

[0165] 3) Sterilize the base material at 90°C for 10 minutes, then cool it to 35°C;

[0166] 4) Inoculate the starter culture and rennet according to Table 4, stir at 50 r / min for 1 min, and ferment until pH=4.8 to obtain curd;

[0167] 5) After the fermented curd is broken by stirring at 50 r / min, it is placed in a refrigerator at 4℃ for 36 h to obtain the finished product (Example 4 Cream Cheese).

[0168] The cream cheese obtained in this embodiment contains 4.4% protein, 3.9% casein, 24% fat, and 2.9% lactose, based on the mass percentage of cream cheese. The casein:whey protein ratio is 89:11.

[0169] The methods for detecting protein content, casein content, lactose content, and fat content are as shown in Example 1.

[0170] Comparative Example 1

[0171] The difference between the preparation method of this comparative example and the preparation method included in this invention is that this comparative example uses the method of adding protein powder in the early stage to increase the protein content and dry matter content of the material, thereby achieving the production of cream cheese without the need for whey discharge. The casein, fat and lactose content contained therein is similar to that of Example 1.

[0172] Table 5

[0173]

[0174] Preparation method:

[0175] (1) Heat the skim milk to 50°C according to Table 5, add the light cream, keep warm and stir for 5 minutes; add casein and white sugar, keep warm and stir for 30 minutes at 150 r / min to obtain hydrated material;

[0176] (2) The material obtained in step (1) is aseptically homogenized at 60°C with a homogenization pressure of 20 MPa to obtain homogenized material;

[0177] (3) Heat the homogeneous material obtained in step (2) to 95°C and keep it warm for 10 minutes to obtain sterilized material;

[0178] (4) Quickly cool the sterilized material obtained in step (3) to the fermentation temperature of 35°C, inoculate with lactic acid bacteria starter and rennet according to Table 5, stir at 50 r / min for 1 min, and ferment until the fermentation endpoint pH=4.8;

[0179] (5) Demulsification and filling: Cut and stir the curd block obtained in step (5) evenly, smooth it until the texture is uniform and there are no obvious particles, fill it and cool it quickly to obtain the finished product (comparative example 1 cream cheese).

[0180] The cream cheese obtained in this comparative example contains 4.1% protein, 3.6% casein, 21% fat, and 2.7% lactose, by weight percentage. The casein:whey protein ratio is 88:12.

[0181] The methods for detecting protein content, casein content, lactose content, and fat content are as shown in Example 1.

[0182] Comparative Example 2

[0183] The preparation method of this comparative example is the same as that of Example 1. The difference is that in step (1), the lactose is not washed, filtered and controlled. According to the mass percentage of the raw material concentrated milk, the obtained raw material concentrated milk contains 6.8% protein, 6.4% casein and 9.0% lactose, of which casein accounts for 94% of the total protein content; thus, the cream cheese of Comparative Example 2 is obtained.

[0184] The cream cheese obtained in this comparative example contains 3.8% protein, 3.5% casein, 20% fat, and 4.8% lactose, by weight percentage. The casein:whey protein ratio is 92:8.

[0185] The methods for detecting protein content, casein content, lactose content, and fat content are as shown in Example 1.

[0186] Comparative Example 3

[0187] The preparation method of this comparative example is the same as that of Example 1, except that in step (1), by retaining casein and washing and filtering, the casein content is made up to 82% of the total protein content, and raw material concentrated milk is obtained. The raw material concentrated milk contains 6.8% protein and 5.6% casein by mass percentage, and the percentage is calculated as a percentage of the mass of the raw material concentrated milk; thus, cream cheese of Comparative Example 3 is obtained.

[0188] The cream cheese obtained in this comparative example contains 3.8% protein, 3.1% casein, 20% fat, and 2.5% lactose, by weight percentage. The casein:whey protein ratio is 82:18.

[0189] The methods for detecting protein content, casein content, lactose content, and fat content are as shown in Example 1.

[0190] Comparative Example 4

[0191] The preparation method of this comparative example is the same as that of Example 1, except that in step (1), the concentration factor is 1.2 to obtain raw material concentrated milk, which contains 4.1% protein and 3.8% casein by mass percentage; thus obtaining the cream cheese of Comparative Example 4.

[0192] The cream cheese obtained in this comparative example contains 2.5% protein, 2.3% casein, 20% fat, and 2.5% lactose, by weight percentage. The casein:whey protein ratio is 92:8.

[0193] The methods for detecting protein content, casein content, lactose content, and fat content are as shown in Example 1.

[0194] Effect Example

[0195] Sensory evaluations were conducted on the products prepared according to the embodiments and comparative proportions described in this invention, assessing the color, texture, flavor, and overall quality of the finished products. 10g of refrigerated sample was placed in a transparent container, and blind testing was performed under natural light or a standard light source. Ten trained sensory evaluators (five men and five women) conducted sensory evaluations of the samples, using evaluation criteria shown in Table 6. Evaluators rinsed their mouths with warm water between samples to eliminate interference. Each indicator was scored out of 5 points, and the final score was the total score.

[0196] Table 6 Sensory Evaluation Criteria

[0197]

[0198] To verify the outstanding effect of the membrane filtration pre-concentration process described in this invention on improving the quality of cream cheese, the following comparative experiments were conducted. Examples 1-4 strictly followed the method of this invention, using a concentrate with a high casein ratio and controllable lactose content obtained through membrane filtration as the core raw material. Comparative Examples 1-3 simulated existing technologies or deviated from the key steps of this invention, respectively, and the results clearly demonstrate the technical advantages of this invention. The results are shown in Table 7:

[0199] All the overall sensory evaluation scores of the embodiments of the present invention were significantly higher than those of the comparative examples. This indicates that the technical solution of the present invention based on concentration before specific membrane filtration can stably and repeatedly produce high-quality cream cheese that is superior in sensory quality to traditional or defective processes.

[0200] By comparing the comparative examples with the embodiments of the present invention, the decisive technical effects contributed by each core technical feature can be analyzed one by one:

[0201] Membrane filtration concentrate has significant advantages over the protein powder addition process. While Comparative Example 1 (direct protein powder addition) maintained its basic structure, its flavor and overall evaluation were significantly lower than all other examples. This demonstrates that even with the same protein content, exogenously added, dried protein powder introduces an unavoidable "powdery" feel and unnatural flavor compounds, severely damaging the pure milky aroma and overall flavor harmony of cream cheese. In contrast, the membrane filtration concentrate used in this invention preserves the natural structure and function of milk proteins to the greatest extent possible, achieving a perfect combination of texture and flavor.

[0202] Precise control of lactose content through washing and filtration is a crucial prerequisite for ensuring fermentation kinetics and flavor purity: Comparative Example 2 (without washing and filtration, resulting in excessively high lactose content) performed poorly in all sensory indicators. Excessive lactose content leads to osmotic pressure imbalance, significantly inhibiting the fermentation activity and metabolic pathways of lactic acid bacteria, resulting in incomplete fermentation, insufficient acidity generation, and a lack of characteristic flavor compounds. Furthermore, excessive residual lactose can lead to uneven sweetness in the product and pose a risk of lactose intolerance. These results demonstrate that precisely controlling the lactose content within the range of 3.0%-6.5% through washing and filtration is an indispensable process step for providing the optimal carbon source environment for subsequent fermentation processes, ensuring normal flavor formation, and guaranteeing product safety.

[0203] The overall evaluation of Comparison 3 (low casein content) was lower. Casein is the main protein that forms the three-dimensional gel network during cheese curdling. Insufficient casein content directly leads to weak curd strength and a sparse, broken protein network. This manifests as a loose texture, lack of elasticity, and a rough mouthfeel, failing to achieve the delicate, smooth texture expected of cream cheese. It also weakens the product's ability to carry and slowly release flavor compounds. This indicates that optimizing membrane processing parameters to increase and stabilize the proportion of casein in the total protein within the high range of 85%-95% is a decisive factor in obtaining a firm texture and a pure, rich flavor in cheese products.

[0204] Comparative Example 4 (concentration ratio less than 2 times) scored only 84 points. Due to the low total solids content, the concentrated milk protein and total solids content were both low, resulting in a thin texture and bland flavor in the finished product. This demonstrates the necessity of the lower limit of the concentration ratio range in this invention.

[0205] The data from the above-described effect examples fully demonstrate that the pre-filtration concentration process of the present invention is not a simple superposition of individual technologies, but a systematic solution with tightly coupled parameters and synergistic functions in each step. It fundamentally eliminates the problem of off-flavor sensation by "replacing exogenous protein powder addition with natural concentration through membrane filtration"; it lays the foundation for pure fermentation flavor generation through "precise sugar control via filtration"; and it constructs the material core of pure texture and flavor in the product by "enriching and maintaining a high proportion of casein". These three aspects are interdependent and synergistic, jointly achieving the outstanding substantial characteristics and significant progress in the sensory quality of the product of the present invention.

[0206] Table 7 Sensory Evaluation Results

[0207]

[0208] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A concentrated milk, characterized in that, The concentrated milk comprises protein and lactose, the mass percentage of the protein is 6.8-10.1% and the mass percentage of the lactose is 4-6% based on the mass of the concentrated milk.

2. The condensed milk according to claim 1, wherein The protein contains casein; preferably, the mass percentage of the casein is 6.4-9.1% based on the mass of the concentrated milk; preferably, the mass of the casein accounts for 90-95% of the mass of the protein; and / or, the concentrated milk is obtained only by concentration.

3. A method of preparing a concentrated milk, characterized in that, The method comprises concentrating raw milk to obtain the concentrated milk according to any one of claims 1-2.

4. The method of claim 3, wherein, The concentration is selected from centrifugal separation, membrane concentration, and vacuum drying concentration; preferably, the membrane concentration is selected from microfiltration membrane or ultrafiltration membrane; preferably, the concentration ratio is 2-3 times; preferably, the transmembrane pressure of the concentration is 1.4-1.8 bar; And / or, the raw milk is selected from skimmed milk; And / or, the method further comprises the step of performing casein retention and / or washing filtration on the concentrated raw milk; preferably, the step of performing casein retention and / or washing filtration is performed after the concentration step is completed.

5. A process for the preparation of a base for cream cheese, characterized in that, The method comprises mixing, homogenizing the concentrated milk according to any one of claims 1-2 or prepared by the method according to any one of claims 3-4 with whipped cream and white sugar to obtain the base; optionally, the method further comprises the steps of sterilization and / or cooling.

6. The method of claim 5, wherein, The mass percentage of the concentrated milk is 36%-47%, the mass percentage of the whipped cream is 50%-60%, and the mass percentage of the white sugar is 3%-4% based on the total mass of the base of the cream cheese; And / or, the pressure of the homogenization is 10-20 Mpa; And / or, the sterilization temperature is 90-95℃.

7. A method for preparing a curd for making cream cheese, characterized in that, The method comprises using a fermenting agent and a rennet enzyme to ferment the base prepared by the method according to any one of claims 5-6 under suitable fermentation conditions to prepare a curd.

8. The method of claim 7, wherein, The ratio of the fermenting agent to the base is 4-5 DCU:100 kg; And / or, the ratio of the rennet enzyme to the base is 0.1-0.3 g:100 kg; And / or, the fermentation comprises fermenting to a pH of 4.0-5.6; And / or, the stirring speed before the fermentation is 25-75 r / min; And / or, the fermenting agent is selected from Lactococcus lactis.

9. A process for the preparation of a cream cheese, characterized in that, The method comprises using the curd prepared by the method according to any one of claims 7-8 to prepare a cream cheese.

10. The method of claim 9, wherein, The method further comprises cooling after the demulsification; preferably, the temperature after the cooling is 0-8℃.

11. Cream cheese prepared according to the method of claim 9 or 10, characterized in that, The cream cheese comprises protein, casein, fat, and lactose, the mass percentage of the protein is 3.2%-5.4%, the mass percentage of the casein is 2.9-4.8%, the mass percentage of the fat is 20%-24%, and the mass percentage of the lactose is 2.2%-3.4% based on the mass of the cream cheese; preferably, the cream cheese contains whey protein, and the mass ratio of the casein to the whey protein is 89:11-92:8.

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