Fresh cheese as well as preparation method and application thereof

Abstract

The invention relates to the technical field of cheese preparation, in particular to fresh cheese as well as a preparation method and application thereof, the preparation method comprises the following steps: standardizing raw milk, homogenizing and sterilizing, fermenting, demulsifying, cooling, heating materials, separating and concentrating, smoothly conveying, canning and refrigerating, and the temperature in the cooling process is less than 18 DEG C; the temperature rising final temperature in the material temperature rising process is 50-60 DEG C; the pH value of the demulsification process is 4.6 to 4.8; by accurately controlling the fermentation temperature of the raw milk, the pH value in the demulsification process and the temperature before product separation, the texture and flavor of the product are improved, and the fermentation time is shortened; compared with the prior art, the taste, texture and stability of the fresh cheese product are improved, the protein content is increased, meanwhile, the production efficiency and yield are improved, the production cost is reduced, the market acceptability of the fresh cheese product is improved, and the fresh cheese product can be widely used for preparing various functional foods.

Description

Technical Field

[0001] The present invention relates to the technical field of cheese preparation, and particularly relates to a fresh cheese, a preparation method thereof, and an application thereof. Background Art

[0002] As a fermented dairy product rich in protein, calcium, and various nutrients, cheese occupies an important position in the global food market. In recent years, with the trend of healthy eating and the growing demand of consumers for diversified dairy products, fresh cheese, due to its soft texture, mild flavor, low-fat, high-protein, and low-carbohydrate characteristics, conforms to the modern healthy eating trend. Fresh cheese is a type of cheese that has not been matured or has only been matured for a short time, and usually adopts a low-temperature and short-time fermentation process, retaining more whey protein and active nutrients, and is deeply favored by the healthy eating group.

[0003] At present, there are still many challenges in the preparation technology of fresh cheese. On the one hand, traditional processes rely on natural starters or empirical strain combinations, resulting in difficult precise control of the temperature during the fermentation process and the pH value during the demulsification process, leading to too long fermentation time, unsatisfactory control of product acidity, a sour and gritty taste, insufficient fineness, and insufficiently strong product flavor. On the other hand, inaccurate control of the processes before and after separation and concentration leads to unstable product quality and rough texture. At the same time, excessive homogenization also results in insufficiently fine product texture, loss of nutrients, and low protein content in the prepared product, making it difficult to meet the needs of consumers for high-protein products and restricting its application range. Summary of the Invention

[0004] In order to solve the problems that the prepared fresh cheese produced by the existing preparation process has a sour and gritty taste, insufficient fineness, and at the same time, the fermentation time is too long and the separation temperature is too high during production, resulting in low production efficiency and product yield, and unstable product quality, the present invention provides a fresh cheese, a preparation method thereof, and an application thereof, which improve the texture and flavor of the fresh cheese product and increase the acceptance of the product in the market by precisely controlling the production process.

[0005] A preparation method of a fresh cheese includes the processes of standardization of raw milk → homogenization and sterilization → fermentation → demulsification → separation and concentration → smooth transportation → canning and refrigeration, and also includes a cooling process after demulsification and a material heating process before separation and concentration. The temperature of the cooling process is < 18°C; the heating end temperature of the material heating process is 50 - 60°C.

[0006] Furthermore, the pH value of the demulsification process is 4.6 - 4.8, the demulsification rotation speed is 500 - 800 rpm, and the demulsification time is 15 - 30 min.

[0007] Further, the raw milk is at least one of fresh whole milk, partially skimmed milk, and skimmed milk.

[0008] Further, in the homogenization and sterilization process, the homogenization pressure is 180 - 200 bar, the sterilization temperature is 90 - 95 °C, and the sterilization time is 300 s.

[0009] Further, the homogenization and sterilization process adopts a multi - stage increasing homogenization process and a stepped sterilization process; among them, the first - stage homogenization pressure is 20 - 30 bar, the second - stage homogenization pressure is 60 - 80 bar, and the third - stage homogenization pressure is 90 - 100 bar.

[0010] Further, the fermentation process is to add fermentation strains and stir - ferment, the stirring temperature is 37 - 45 °C, the stirring speed is 500 - 800 rpm, and the stirring time is 15 - 30 min.

[0011] Further, the fermentation strains are at least one of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus salivarius subsp. thermophilus, Lactococcus lactis subsp. lactis, Lactococcus cremoris, Lactococcus lactis subsp. diacetylactis, Leuconostoc mesenteroides, Lactobacillus rhamnosus, Lactobacillus plantarum, and Bifidobacterium longum.

[0012] Further, the separation and concentration process adopts a centrifuge for concentration, and the flow rate of the centrifuge is 6000 - 8000 L / h; the smooth conveying process adopts a smooth pump, and the power of the smooth pump is 30 - 50 Hz, and the refrigeration temperature in the canning and refrigeration process is 2 - 8 °C.

[0013] The present invention prepares a fresh cheese according to the above - mentioned preparation method.

[0014] The present invention also provides the application of the fresh cheese prepared by the above - mentioned preparation method in the preparation of functional foods for improving intestinal flora or high - protein nutritional foods.

[0015] The advantages of the present invention are as follows:

[0016] The present invention provides a preparation method of fresh cheese. By adding unique fermentation strains and controlling the fermentation temperature of raw milk, the texture and flavor of the product are improved, the viscosity and buttery flavor of the product are increased, and the fermentation time is shortened; at the same time, the pH value and cooling temperature during the demulsification process are controlled to minimize the acidity of the product, improve the product flavor and acceptance; strictly control the temperature before product separation to improve the yield and texture of the finished product. Compared with the prior art, the taste, texture and stability of the fresh cheese product are improved, the protein content is increased, the production efficiency and yield are improved, the production cost is reduced, the market acceptance of the fresh cheese product is improved, and it can be widely used in the preparation of various functional foods. Description of the Drawings

[0017] Figure 1 This is the process flow diagram for the preparation of a fresh cheese according to the present invention. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] It should be noted that the installation methods and technical terms mentioned in the present invention are all technical terms that have been clearly known in the technical field to which they belong, so no further explanation will be given. In addition, the same reference numerals are used for the same components, but this does not affect and should not constitute an inaccurate understanding of the technical solution by those skilled in the art.

[0020] Example 1

[0021] This example provides a method for preparing fresh cheese. As Figure 1 shown, the specific preparation process is as follows:

[0022] Step 1. Standardization of raw milk: The raw milk that has passed the inspection (the raw milk in this example is fresh whole milk purchased from a ranch) is sent to a milk storage tank, and a centrifuge is used to remove the fat in the milk to obtain skim milk.

[0023] Step 2. Homogenization and sterilization: After heating the skim milk obtained in Step 1 to 55°C, it is homogenized through a multi-stage increasing homogenization process with a primary homogenization pressure of 30 bar, a secondary homogenization pressure of 60 bar, and a tertiary homogenization pressure of 90 bar. The total homogenization pressure is 180 bar; the homogenized skim milk is sterilized at a sterilization temperature of 95°C and a sterilization time of 300 s.

[0024] Step 3. Fermentation: The temperature of the material after sterilization in Step 2 is controlled at 37°C, and a fermentation strain is added for fermentation (the fermentation strain in this example is Lactococcus lactis subsp. diacetylactis and Leuconostoc mesenteroides), and it is incubated at 37°C for 4 h.

[0025] Step 4. Demulsification: When the pH of the fermented milk obtained in Step 3 reaches 4.8, it is stirred and demulsified at a speed of 800 rpm for 15 min.

[0026] Step 5. Cooling: The material after demulsification in Step 4 is cooled to below 18°C with ice water to prevent the pH from continuing to drop.

[0027] Step 6. Heating of the material: Heat the material after cooling in Step 5 to 50°C and maintain for 300 s;

[0028] Step 7. Separation and concentration: Feed the material after heating in Step 6 to a centrifuge, control the feed rate at 8000 L / h, centrifuge at a speed of 6000 rpm to achieve separation and concentration of the product;

[0029] Step 8. Smooth transportation: Transport the product after separation and concentration in Step 7 to the tank to be filled through a smooth pump, and the power of the smooth pump is 30 Hz;

[0030] Step 9. Canning and refrigeration: Fill the material into a sterile package under sterile conditions and quickly refrigerate at 2 - 8°C.

[0031] Example 2

[0032] A method for preparing fresh cheese provided in this example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0033] In this example, the homogenization temperature in the homogenization and sterilization process of Step 2 is 60°C, the primary homogenization pressure of the multi-stage incremental homogenization process is 20 bar, the secondary homogenization pressure is 80 bar, the tertiary homogenization pressure is 100 bar, and the total homogenization pressure is 200 bar.

[0034] In this example, the fermentation temperature in the fermentation process of Step 3 is 45°C and the fermentation time is 4 h.

[0035] In this example, the pH in the demulsification process of Step 4 is 4.6, the demulsification speed is 500 rpm, and the demulsification time is 30 min.

[0036] In this example, the end temperature in the material heating process before separation and concentration in Step 6 is 60°C and the time is 300 s.

[0037] In this example, the power of the smooth pump in the smooth transportation process of Step 8 is 50 Hz.

[0038] Example 3

[0039] A method for preparing fresh cheese provided in this example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0040] In this example, the homogenization temperature in the homogenization and sterilization process of Step 2 is 60°C, the primary homogenization pressure of the multi-stage incremental homogenization process is 30 bar, the secondary homogenization pressure is 80 bar, the tertiary homogenization pressure is 90 bar, and the total homogenization pressure is 200 bar.

[0041] In this example, the fermentation temperature in the fermentation process of Step 3 is 37°C and the fermentation time is 5 h.

[0042] In this embodiment, the pH during the demulsification process in step 4 is 4.7, the demulsification rotation speed is 800 rpm, and the demulsification time is 30 min.

[0043] In this embodiment, the feed rate during the separation and concentration process in step 7 is 6000 L / h.

[0044] In this embodiment, the power of the smoothing pump during the smooth conveying process in step 8 is 50 Hz.

[0045] Comparative Example 1

[0046] The preparation method of the fresh cheese in this comparative example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0047] In this comparative example, the fermentation temperature during the fermentation process in step 3 is 30 °C, and the fermentation time is 8 h.

[0048] In this comparative example, the power of the smoothing pump during the smooth conveying process in step 8 is 50 Hz.

[0049] Comparative Example 2

[0050] The preparation method of the fresh cheese in this comparative example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0051] In this comparative example, the pH during the demulsification process in step 4 is 4.5.

[0052] In this comparative example, the power of the smoothing pump during the smooth conveying process in step 8 is 50 Hz.

[0053] Comparative Example 3

[0054] The preparation method of the fresh cheese in this comparative example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0055] In this comparative example, the end temperature during the material heating process before separation and concentration in step 6 is 45 °C, and the time is 300 s.

[0056] In this comparative example, the power of the smoothing pump during the smooth conveying process in step 8 is 50 Hz.

[0057] Comparative Example 4

[0058] The preparation method of the fresh cheese in this comparative example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0059] In this comparative example, the end temperature during the material heating process before separation and concentration in step 6 is 65 °C, and the time is 300 s.

[0060] In this comparative example, the power of the smoothing pump during the smooth conveying process in step 8 is 50 Hz.

[0061] Comparative Example 5

[0062] The preparation method of the fresh cheese in this comparative example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0063] The feed rate in the separation and concentration process of Step 7 in this comparative example is 5000 L / h.

[0064] The power of the smoothing pump in the smoothing transportation process of Step 8 in this comparative example is 50 Hz.

[0065] Comparative Example 6

[0066] The preparation method of the fresh cheese in this comparative example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0067] The power of the smoothing pump in the smoothing transportation process of Step 8 in this comparative example is 25 Hz.

[0068] Comparative Example 7

[0069] The preparation method of the fresh cheese in this comparative example is the same as that in Example 1, except that the parameter conditions in the preparation process are different:

[0070] In this comparative example, the multi-stage increasing homogenization process was not adopted in the homogenization and sterilization process of Step 2, and homogenization was directly carried out at a pressure of 180 bar.

[0071] Test Example 1

[0072] In this test example, the fresh cheese prepared in Examples 1-3 and Comparative Examples 1-7 was subjected to a sensory evaluation of taste and flavor after 30 days of refrigeration. The main evaluation items included: tissue state (viscosity, fineness, presence or absence of whey separation, etc.), taste, flavor, acidity, etc. The test process was as follows: 30 people with food-related work experience or currently engaged in food work were randomly selected for evaluation, aged 25-45 years old. They conducted a sensory evaluation and scoring on each group of fresh cheese. Before the sensory evaluation of each product, they needed to rinse their mouths with mineral water and score according to the fresh cheese sensory quality scoring standard in Table 1. The sensory scores of the examples and comparative examples are shown in Table 2:

[0073] Table 1 Fresh Cheese Sensory Quality Scoring Standard

[0074]

[0075] Table 2 Sensory Scores of Fresh Cheese Prepared in Examples and Comparative Examples

[0076]

[0077]

[0078] As can be seen from the evaluation results in Table 2, the fresh cheese of Examples 1-3 has good texture, taste, flavor and acidity, no whey separation, delicate texture, good characteristic aroma and moderate acidity, which conforms to the general taste and is more acceptable. Among them, Example 1 has the highest evaluation score and is the optimal example of this application. The comprehensive scores of the fresh cheese prepared by the methods of Comparative Examples 1-7 are relatively low, and they are inferior to those of the examples in terms of texture, taste, flavor and acidity, indicating that the process parameter conditions in the preparation process will affect the quality of the prepared fresh cheese.

[0079] Comparing the results of Example 1 and Comparative Example 1, although the texture of both Example 1 and Comparative Example 1 is good, the characteristic aroma is obvious and the acidity is moderate, meeting the general taste requirements. However, the fermentation time of Comparative Example 1 is 7-8h, which is significantly longer than 3-4h of Example 1, reducing the production efficiency and increasing the energy consumption. This shows that the fermentation temperature will affect its fermentation efficiency, and a suitable fermentation temperature can shorten the fermentation duration and reduce the production cost.

[0080] Comparing the results of Example 1 and Comparative Example 2, Example 1 has good flavor and acidity, obvious characteristic aroma and moderate acidity; while Comparative Example 2 has a higher acidity and a weakened flavor, affecting the overall preference; indicating that the demulsification pH value directly affects the acidity and flavor of the product.

[0081] Comparing the results of Example 1 with those of Comparative Examples 3 and 4, Example 1 and Comparative Example 3 have good flavor and acidity, obvious characteristic aroma and moderate acidity; while Comparative Example 4 has a rough texture, obvious whey separation, good characteristic aroma and moderate acidity; indicating that the temperature before separation and concentration has a greater impact on the texture of the product and needs to be strictly controlled. If the temperature rises too high before separation and concentration, it will lead to a rough texture, whey precipitation, and the higher the temperature rise, the greater the energy consumption.

[0082] Comparing the results of Example 1, Example 2, Example 3 and Comparative Example 5, Examples 1, 2 and 3 have a delicate taste, no whey separation, and a relatively high product viscosity, while Comparative Example 5 has a delicate texture but low viscosity and a small amount of whey separation, indicating that the flow rate during separation and concentration will affect the viscosity of the product, resulting in a poor taste, and the material conveying flow rate during separation and concentration needs to be strictly controlled.

[0083] Comparing the results of Example 1, Example 2, Example 3 and Comparative Example 6, Examples 1, 2 and 3 have a delicate and smooth taste and no whey separation; while Comparative Example 6 has a small amount of small particles, slightly separated whey and a slightly rough taste, indicating that the smooth pump power during the conveying process will also affect the texture and taste of the product and needs to be strictly controlled.

[0084] Comparing the results of Example 1, Example 2, Example 3 and Comparative Example 6, the fresh cheese prepared in Example 1, 2 and 3 has a delicate and smooth taste and no whey separation; while that in Comparative Example 7 has a rough texture, slight whey separation and slight granularity, indicating that the homogenization pressure and homogenization method in the homogenization process will affect the texture of the product.

[0085] From the above sensory evaluation results, it can be seen that changing the process conditions will affect the taste, texture and flavor of the product, making the prepared fresh cheese taste sour and gritty, not delicate enough, and having a rough texture, resulting in a decline in its overall effect.

[0086] Test Example 2

[0087] In this test example, the protein content of the fresh cheese obtained by the preparation methods of Examples 1-3 and Comparative Examples 1-7 was detected. The determination of the protein content was carried out by the first method in GB 5009.5-2016 National Food Safety Standard - Determination of Protein in Foods. The test results are shown in Table 3:

[0088] Table 3 Test Results of Protein Content of Fresh Cheese

[0089]

[0090] As can be seen from Table 3, the protein content of the fresh cheese prepared by the preparation method of the present invention in each example reaches more than 10%. Compared with Examples 1-3, the protein content of Comparative Example 3 is 9.53%; it can be seen that the low temperature rise before concentration leads to a low protein content in the finished product. Comparing Examples 1-3 with Comparative Example 5, the protein content in the examples is more than 10%, while that of Comparative Example 5 is 7.53%. It can be seen that reducing the flow rate of the separation concentrator can lead to a low protein content in the finished product.

[0091] Test Example 3

[0092] In this test example, a rheometer was used to detect the viscosity of the fresh cheese obtained by the preparation methods of Examples 1-3 and Comparative Examples 1-7. The results are shown in Table 4:

[0093] Table 4 Test Results of Viscosity of Fresh Cheese

[0094]

[0095] As can be seen from Table 4, the viscosity of the fresh cheese prepared by the preparation method of the present invention in each example is above 760 g·sec. Compared with the results of Examples 1-3, the viscosity of Comparative Example 5 is lower, which is 689.693 g·sec; it can be seen that the material flow rate directly affects the viscosity of the product.

[0096] For those skilled in the art, the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0097] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any minor modifications, equivalent replacements, and improvements made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing fresh cheese, comprising the processes of standardization of raw milk → homogenization and sterilization → fermentation → demulsification → separation and concentration → smooth conveying → canning and refrigeration, characterized in that, It also includes the cooling process after demulsification and the heating process of the material before separation and concentration. The temperature of the cooling process is <18°C; the final temperature of the heating process of the material is 50 - 60°C.

2. The method for preparing fresh cheese according to claim 1, characterized in that, The pH value of the demulsification process is 4.6 - 4.8, the demulsification rotation speed is 500 - 800 rpm, and the demulsification time is 15 - 30 min.

3. The method for preparing fresh cheese according to claim 1, characterized in that, The raw milk is at least one of fresh whole milk, partially skimmed milk, and skimmed milk.

4. The method for preparing fresh cheese according to claim 1, characterized in that, The total homogenization pressure of the homogenization and sterilization process is 180 - 200 bar, the sterilization temperature is 90 - 95°C, and the sterilization time is 300 s.

5. The method for preparing fresh cheese according to claim 4, characterized in that, The homogenization and sterilization process adopts a multi - stage incremental homogenization process. Among them, the first - stage homogenization pressure is 20 - 30 bar, the second - stage homogenization pressure is 60 - 80 bar, and the third - stage homogenization pressure is 90 - 100 bar.

6. The method for preparing fresh cheese according to claim 1, wherein The fermentation process is stirring fermentation with the addition of fermentation strains. The stirring temperature is 37 - 45°C, the stirring speed is 500 - 800 rpm, and the stirring time is 15 - 30 min.

7. The method for preparing fresh cheese according to claim 5, characterized in that, The fermentation strains are at least one of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus salivarius subsp. thermophilus, Lactococcus lactis subsp. lactis, Lactococcus cremoris, Lactococcus lactis subsp. diacetylactis, Leuconostoc mesenteroides, Lactobacillus rhamnosus, Lactobacillus plantarum, and Bifidobacterium longum.

8. The method for preparing fresh cheese according to claim 1, characterized in that, The separation and concentration process adopts a centrifuge for concentration, and the flow rate of the centrifuge is 6000 - 8000 L / h; the smooth transportation process adopts a smooth pump, and the power of the smooth pump is 30 - 50 Hz. The refrigeration temperature of the canning and refrigeration process is 2 - 8°C.

9. A fresh cheese, characterized in that, Prepared by using the preparation method according to any one of claims 1 - 8.

10. An application of the fresh cheese according to claim 9 in the preparation of functional foods for improving intestinal flora or in the preparation of high - protein nutritional foods.

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