A processed cheese and its preparation method

Abstract

This invention relates to the field of food processing technology, specifically to a processed cheese and its preparation method. The processed cheese provided by this invention is prepared from the following raw materials in parts by weight: 14-30 parts of virgin cheese, 2-4 parts of dairy raw material, 1-3 parts of emulsifier, 30-55 parts of tea extract, and 20-35 parts of oil. This processed cheese contains tea extract, possesses a good flavor, and exhibits good antioxidant and antibacterial properties, significantly delaying fat oxidation and microbial growth. Furthermore, the processed cheese has stable texture, produces less protein clumping and oil-water separation, and demonstrates excellent stability. This is beneficial for extending the shelf life of the processed cheese product and ensuring its flavor and quality during the shelf life, thus possessing significant application value.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a processed cheese and its preparation method. Background Technology

[0002] With continued economic development and rising consumption levels, public acceptance of cheese sauces has gradually improved, and cheese sauces are widely used as breakfast side dishes and snacks. However, cheese sauces, being semi-liquid in texture, are particularly suitable for microbial growth and reproduction due to their high protein and carbohydrate content. The high oil content also easily alters the product's flavor, producing a noticeable oxidized oil taste. If bacterial inhibition and oil oxidation are not effectively controlled, the product can easily become rancid or spoiled, negatively impacting its flavor and quality. Existing processed cheese products have short shelf lives, poor stability, are prone to oxidation and off-flavors, and offer a relatively limited range of flavors. Summary of the Invention

[0003] The purpose of this invention is to provide a processed cheese and a method for preparing the same.

[0004] Tea extract is rich in active ingredients such as tea polyphenols, which have antibacterial and antioxidant effects, and can also enrich the flavor and taste of food. This invention develops a processed cheese containing tea extract by adding it to the raw materials used in the preparation of processed cheese.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] This invention provides a processed cheese, which is prepared from the following raw materials in parts by weight: 14-30 parts of virgin cheese, 2-4 parts of dairy raw material, 1-3 parts of emulsifier, 30-55 parts of tea extract, and 20-35 parts of oil.

[0007] This invention discovers that adding tea extract can improve the antibacterial and antioxidant properties of processed cheese. The effects of tea extracts from different tea sources on these properties vary. Furthermore, this invention unexpectedly found that while tea extracts from various tea sources can significantly enhance the antibacterial and antioxidant properties of processed cheese, the antibacterial and antioxidant properties of many tea extracts rapidly decline with prolonged storage of the cheese. Through continuous research, this invention found that the stability of tea polyphenols in tea extracts from different tea sources is one of the key reasons for this problem. After extensive screening, this invention found that tea extract prepared from oolong tea has a significantly better effect on improving the antibacterial and antioxidant properties of processed cheese than other teas. More importantly, the tea polyphenols in oolong tea extract are significantly more stable, allowing them to better exert their antioxidant and antibacterial effects during the storage of processed cheese.

[0008] Preferably, the tea extract is an oolong tea extract.

[0009] The oolong tea extract mentioned above is an extract prepared by extracting oolong tea as raw material.

[0010] To better ensure that the tea extract exerts its antibacterial and antioxidant effects, the content of tea polyphenols in the tea extract is preferably 10-20%, more preferably 12-20%.

[0011] Preferably, the method for preparing the tea extract includes: mixing tea leaves with water and then extracting at 65-95℃ (preferably 80-90℃) for 1-2 hours (preferably 1.2-1.8 hours), and collecting the extract after solid-liquid separation.

[0012] For oolong tea, the above method can better preserve the content of tea polyphenols, and the tea polyphenols in the resulting tea extract have high stability.

[0013] In the above method for preparing tea extract, the preferred mass ratio of tea leaves to water is 1:(10-40). More preferably, it is 1:(15-25).

[0014] In the above method for preparing tea extract, the tea leaves are first crushed and passed through a 45-55 mesh sieve before being mixed with water.

[0015] Although tea polyphenols are known antibacterial and antioxidant active ingredients in tea extracts, this invention has found that, compared to adding tea polyphenols alone, adding tea extracts not only enhances the flavor of processed cheese but also significantly improves its antibacterial and antioxidant properties. Furthermore, compared to solid or paste-like concentrates containing tea extracts, this invention has found that directly adding tea extracts, using them instead of water in the processing of processed cheese raw materials, significantly improves the stability and antibacterial and antioxidant properties of active ingredients such as tea polyphenols in the tea extract, thus further enhancing the stability of processed cheese products and extending their shelf life.

[0016] Therefore, in the above method for preparing tea extract, the extract collected by solid-liquid separation does not need to be concentrated or otherwise processed. It can be directly added to the raw material of processed cheese as tea extract, replacing water in the processing of raw materials for processed cheese.

[0017] Preferably, water is not added separately to the raw materials for the processed cheese.

[0018] The phrase "no water is added separately to the raw materials of processed cheese" means that, apart from the water contained in the tea extract and the water contained in other raw materials, no water is added separately as a raw material.

[0019] Preferably, in the processed cheese, the mass ratio of protein to fat is (0.5-0.8):1.

[0020] The protein content is 12-25% by mass, and the fat content is 16-30% by mass.

[0021] Preferably, the processed cheese has a protein content of 14-21% and a fat content of 19-29% by mass.

[0022] This invention has found that adding tea extract affects the texture of processed cheese, and that controlling the ratio of protein to fat in processed cheese within the above-mentioned range can better ensure the stability of the texture of processed cheese and improve its texture and shelf-life stability.

[0023] In the raw materials of the processed cheese described above, the emulsifier is selected from any one or a combination of at least two of sodium citrate, disodium hydrogen phosphate, sodium hexametaphosphate, and sodium polyphosphate.

[0024] Preferably, the emulsifier is disodium hydrogen phosphate and sodium polyphosphate in a mass ratio of (2-4):1, or the emulsifier is sodium hexametaphosphate, sodium polyphosphate and disodium hydrogen phosphate in a mass ratio of (1.2-2):1:(0.4-1).

[0025] Using the above-mentioned emulsifier formula can better ensure the stability of active ingredients such as tea polyphenols in tea extract during the storage of processed cheese, enabling them to better exert their antibacterial and antioxidant effects during storage, preventing microbial growth and fat oxidation odors during storage, and also improving the textural stability of the processed cheese product itself with added tea extract and the above-mentioned protein and fat content ratio, reducing protein clumping in the product and oil-water separation and water separation during storage.

[0026] More preferably, the emulsifier is disodium hydrogen phosphate and sodium polyphosphate in a mass ratio of (2.5-3.5):1, or the emulsifier is sodium hexametaphosphate, sodium polyphosphate and disodium hydrogen phosphate in a mass ratio of (1.3-1.6):1:(0.4-1).

[0027] When using the above emulsifier system, it is preferable to ensure that the mass ratio of emulsifier to tea polyphenols is (1-2):(4-8). Using emulsifier within this range better ensures the stability of active ingredients such as tea polyphenols in the tea extract during the storage of processed cheese.

[0028] Among the raw materials for the processed cheeses mentioned above, the native cheese is selected from any one or a combination of at least two of the following: Holland cheese, Cheese, and Gouda cheese.

[0029] Preferably, the native cheese is a mixture of Cheddar and Gouda cheese in a mass ratio of (8-20):(10-12), or a mixture of Hollandaise and Gouda cheese in a mass ratio of (4-13):(10-12).

[0030] The fat is selected from any one or a combination of at least two of cream and butter.

[0031] Preferably, the fat is butter or cream, or cream and butter in a mass ratio of (5-15):(5-25).

[0032] The milk raw material is selected from any one or a combination of at least two of whey protein powder, milk powder, and sodium caseinate.

[0033] Preferably, the milk raw material is whey protein powder and sodium caseinate in a mass ratio of (0.5-2):1, or whey protein powder and milk powder in a mass ratio of 1:(1-2), or milk powder and sodium caseinate in a mass ratio of (1-2):1.

[0034] In addition to the above-mentioned ingredients, processed cheese may also include sweeteners and acidity regulators.

[0035] Preferably, the sweetener is any one or a combination of at least two selected from white sugar, cyclamate, sucralose, aspartame, steviol glycosides, and mogrosides.

[0036] The acidity regulator is selected from any one or a combination of two of citric acid and lactic acid.

[0037] In some embodiments of the present invention, the raw materials of the processed cheese include the following components in parts by weight: 14-30 parts of native cheese, 2-4 parts of milk raw material, 1-3 parts of emulsifier, 30-55 parts of tea extract, 20-35 parts of oil, 1-3 parts of sweetener, and 1-2 parts of acidity regulator.

[0038] In some embodiments of the present invention, the raw materials of the processed cheese are composed of the following components in parts by weight: 14-30 parts of native cheese, 2-4 parts of milk raw material, 1-3 parts of emulsifier, 30-55 parts of tea extract, 20-35 parts of oil, 1-3 parts of sweetener, and 1-2 parts of acidity regulator.

[0039] In some embodiments of the present invention, the raw materials for the processed cheese are composed of the following components in parts by weight: 5-12 parts of Cheddar cheese, 9-18 parts of Gouda cheese, 0.5-1.5 parts of whey protein powder, 1.5-2.5 parts of milk powder, 0.5-1 part of sodium hexametaphosphate, 0.3-0.8 parts of sodium polyphosphate, 0.3-0.8 parts of disodium hydrogen phosphate, 40-50 parts of tea extract (tea polyphenol content 12-15%), 20-30 parts of butter, 1-3 parts of white sugar, and 1-2 parts of lactic acid.

[0040] The processed cheese provided by this invention can be used as a cheese spread, with good flavor, texture and spreadability, excellent antibacterial and antioxidant properties, stable texture, and significantly improved stability during shelf life.

[0041] The present invention also provides a method for preparing the above-mentioned processed cheese, the method comprising: mixing native cheese, fat and tea extract accounting for 30-40% of the total mass of tea extract at 60-95°C to obtain a first raw material mixture;

[0042] The first raw material mixture is mixed with the remaining tea extract, milk raw material, sweetener and acidity regulator, and then mixed with emulsifier to obtain the second raw material mixture;

[0043] The second raw material mixture is boiled at 90-98℃ for 10-20 minutes.

[0044] Preferably, the preparation method includes the following steps:

[0045] (1) Mix raw cheese, fat and tea extract accounting for 30-35% of the total mass of tea extract, heat to 70-80℃, and stir continuously for 10-20 minutes to obtain the first raw material mixture;

[0046] (2) Mix the first raw material mixture with the remaining tea extract, milk raw material, sweetener and acidity regulator, and stir intermittently. Each stirring lasts for 2-4 minutes, and the stirring speed is 7000-9000 rpm. After each stirring is stopped, the temperature is raised by 4-6℃. The total stirring time is 10-15 minutes. When the stirring is finally finished, the temperature reaches 90-95℃. Then add the emulsifier and stir to mix well to obtain the second raw material mixture.

[0047] (3) Sterilize the second raw material mixture by stirring and boiling at 94-96℃ for 13-18 minutes.

[0048] The sterilized raw materials are processed cheese. After being packaged and refrigerated, the processed cheese is the finished product.

[0049] The beneficial effects of this invention are as follows: the processed cheese containing tea extract provided by this invention has good flavor, taste, color, texture and spreadability, and also has good antioxidant and antibacterial properties, which can significantly delay fat oxidation and microbial growth. Moreover, the processed cheese has stable texture, produces less protein clumping and oil-water separation, and has excellent stability, which is conducive to extending the shelf life of processed cheese products and ensuring the flavor and quality of the products within the shelf life, and has good application value. Attached Figure Description

[0050] Figure 1The results are the stability analysis results of the processed cheese in Example 1 of this invention.

[0051] Figure 2 The results are the stability analysis results of the processed cheese in Example 2 of this invention.

[0052] Figure 3 The results are the stability analysis results of the processed cheese in Example 3 of this invention.

[0053] Figure 4 The results of the stability analysis of the processed cheese in Comparative Example 1 of this invention are shown.

[0054] Figure 5 The results of the stability analysis of the processed cheese in Comparative Example 2 of this invention are shown.

[0055] Figure 6 The results of the stability analysis of the processed cheese in Comparative Example 3 of this invention are shown.

[0056] Figure 7 The results of the stability analysis of the processed cheese in Comparative Example 4 of this invention are shown. Detailed Implementation

[0057] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0058] Example 1

[0059] This embodiment provides a processed cheese, the raw materials of which are composed of the following components in parts by weight: 14 parts of native cheese (4 parts of Dutch cheese, 10 parts of Gouda cheese), 4 parts of milk raw materials (2 parts of whey protein powder, 2 parts of sodium caseinate), 2 parts of emulsifier (1.5 parts of disodium hydrogen phosphate, 0.5 parts of sodium polyphosphate), 55 parts of oolong tea extract (13% tea polyphenol content), 20 parts of fat (15 parts of light cream, 5 parts of butter), 3 parts of sweetener (0.5 parts of white sugar, 1 part of mogroside, 1.5 parts of aspartame), and 2 parts of acidity regulator (1 part of citric acid, 1 part of lactic acid).

[0060] The above processed cheese contains 14.16% protein and 19% fat.

[0061] This embodiment also provides a method for preparing the above-mentioned processed cheese, the steps of which are as follows:

[0062] (1) Weigh 12g of oolong tea according to the formula, crush it and pass it through a 50-mesh sieve, add purified water to make the solid-liquid ratio 1:20, extract at 85℃, and soak for 1.5h. The extract is obtained with the tea polyphenol extraction rate as the indicator, and the tea polyphenol content is 13%.

[0063] (2) Mix the raw cheese, fat and tea extract (1 / 3 of the total mass of tea extract) and heat to 75°C. Stir continuously for 15 minutes to obtain the first raw material mixture.

[0064] (3) Add the remaining tea extract, milk raw material, sweetener, and acidity regulator to the first raw material mixture. After mixing, stir intermittently for 3 minutes each time at a stirring rate of 8000 rpm. After each stirring stops, raise the temperature by 5°C. The interval between two adjacent stirrings is 1 minute. The total stirring time is 12 minutes. When the stirring ends, the temperature reaches 95°C. Add emulsifier and stir to mix well to obtain the second raw material mixture.

[0065] (4) The second raw material mixture is kept at 95°C, stirred and boiled for 15 minutes to sterilize, then filled and refrigerated.

[0066] Example 2

[0067] This embodiment provides a processed cheese, the raw materials of which are composed of the following components in parts by weight: 20 parts of native cheese (8 parts of cheddar cheese, 12 parts of gouda cheese), 2.5 parts of milk raw materials (1 part of whey protein powder, 1.5 parts of milk powder), 2 parts of emulsifier (0.8 parts of sodium hexametaphosphate, 0.6 parts of sodium polyphosphate, 0.6 parts of disodium hydrogen phosphate), 47 parts of oolong tea extract (tea polyphenol content 13%), 25 parts of butter, 2 parts of white sugar, and 1.5 parts of lactic acid.

[0068] The above processed cheese contains 14.25% protein and 23.75% fat.

[0069] This embodiment also provides a method for preparing the above-mentioned processed cheese, which is the same as the preparation method in Example 1.

[0070] Example 3

[0071] This embodiment provides a processed cheese, the raw materials of which are composed of the following components in parts by weight: 25 parts of native cheese (13 parts of Holland cheese, 12 parts of Gouda cheese), 3.5 parts of milk raw materials (2 parts of milk powder, 1.5 parts of sodium caseinate), 1.5 parts of emulsifier (0.8 parts of sodium hexametaphosphate, 0.5 parts of sodium polyphosphate, 0.2 parts of disodium hydrogen phosphate), 35 parts of oolong tea extract (13% tea polyphenol content), 30 parts of fat (5 parts of light cream, 25 parts of butter), 3 parts of sweetener (1.0 part of white sugar, 1.0 part of cyclamate, 1.0 part of steviol glycosides), and 2 parts of acidity regulator (1.5 parts of lactic acid, 0.5 parts of citric acid).

[0072] The above processed cheese contains 20.83% protein and 28.5% fat.

[0073] This embodiment also provides a method for preparing the above-mentioned processed cheese, which is the same as the preparation method in Example 1.

[0074] Comparative Example 1

[0075] This comparative example provides a processed cheese, the raw materials of which consist of the following components in parts by weight: 20 parts of native cheese (8 parts of cheddar cheese, 12 parts of gouda cheese), 2.5 parts of milk raw materials (1 part of whey protein powder, 1.5 parts of milk powder), 2 parts of emulsifier (0.8 parts of sodium hexametaphosphate, 0.6 parts of trisodium phosphate, 0.6 parts of potassium citrate), 47 parts of oolong tea extract (13% tea polyphenol content), 25 parts of butter, 2.0 parts of white sugar, and 1.5 parts of lactic acid.

[0076] The above processed cheese contains 14.42% protein and 23.75% fat.

[0077] The preparation method of the above-mentioned processed cheese is the same as that of Example 1.

[0078] Comparative Example 2

[0079] This comparative example provides a processed cheese whose raw materials consist of the following components in parts by weight: 20 parts of native cheese (8 parts of cheddar cheese, 12 parts of gouda cheese), 2.5 parts of dairy raw materials (1 part of whey protein powder, 1.5 parts of milk powder), 2 parts of emulsifier (0.8 parts of sodium hexametaphosphate, 0.6 parts of sodium polyphosphate, 0.6 parts of disodium hydrogen phosphate), 47 parts of water, 25 parts of butter, 2 parts of white sugar, and 1.5 parts of lactic acid.

[0080] The above processed cheese contains 14.42% protein and 23.75% fat.

[0081] The preparation method of the above-mentioned processed cheese is the same as that of Example 1.

[0082] Comparative Example 3

[0083] This comparative example provides a processed cheese, the raw materials of which consist of the following components in parts by weight: 20 parts of native cheese (8 parts of cheddar cheese, 12 parts of gouda cheese), 2.5 parts of milk raw materials (1 part of whey protein powder, 1.5 parts of milk powder), 2 parts of emulsifier (0.8 parts of sodium hexametaphosphate, 0.6 parts of sodium polyphosphate, 0.6 parts of disodium hydrogen phosphate), 47 parts of black tea extract (13% tea polyphenol content), 25 parts of butter, 2 parts of white sugar, and 1.5 parts of lactic acid.

[0084] The above processed cheese contains 14.42% protein and 23.75% fat.

[0085] The steps for preparing the above-mentioned processed cheese are as follows:

[0086] (1) Weigh 15g of black tea according to the formula, crush it and pass it through a 50-mesh sieve. Select a solid-liquid ratio of 1:20, an extraction temperature of 90℃, and an extraction time of 1.5h. The extract is obtained with the tea polyphenol extraction rate as the indicator, and the tea polyphenol content is 13%.

[0087] (2) Mix the raw cheese, oil and tea extract (1 / 3 of the total mass of tea extract) and heat to 85°C. Stir continuously for 15 minutes to obtain the first raw material mixture.

[0088] (3) Add the remaining tea extract, milk raw material, sweetener and acidity regulator to the first raw material mixture and mix. Stir at 7500 rpm for 10 minutes. Then add emulsifier and stir until well mixed to obtain the second raw material mixture.

[0089] (4) The second raw material mixture is kept at 95°C, stirred and boiled for 15 minutes to sterilize, then filled and refrigerated.

[0090] Comparative Example 4

[0091] This comparative example provides a processed cheese, the raw materials of which consist of the following components in parts by weight: 30 parts of native cheese (20 parts of Cheese, 10 parts of Gouda cheese), 2 parts of whey protein powder, 1 part of emulsifier (0.4 parts of sodium citrate, 0.6 parts of sodium hexametaphosphate), 30 parts of oolong tea extract (13% tea polyphenol content), 35 parts of light cream, 1 part of sweetener (0.5 parts of white sugar, 0.5 parts of sucralose), and 1 part of citric acid.

[0092] The above processed cheese contains 20.12% protein and 33.25% fat.

[0093] The preparation method of the above-mentioned processed cheese is the same as that of Example 1.

[0094] Sensory evaluation of processed cheese in Experiment Example 1

[0095] 1. Experimental materials: Reconstituted cheese from Examples 1-3 and Comparative Examples 1-4.

[0096] 2. Test method: The processed cheeses of Examples 1-3 and Comparative Examples 1-4 were stored at 4°C and subjected to sensory tasting at different storage times to evaluate the flavor, color, taste and spreadability of the products. The evaluation criteria are shown in Table 1.

[0097] Table 1 Sensory Evaluation Index System

[0098]

[0099]

[0100] The sensory evaluation results during the shelf-life storage period are shown in Table 2. The results show that tea polyphenols themselves are pale yellow or brown with a slightly bitter taste. After adding tea extract, the overall color of the product deepens to a deep yellow. Tea polyphenols can improve lipid oxidation. The processed cheeses of Examples 1-3 and Comparative Examples 1-4 were stored for 1 day, 7 days, 14 days, and 21 days during the shelf life. They were scored in five aspects: flavor, taste, color, texture, and spreadability. Compared with other examples and comparative examples, the specific protein-to-fat ratio and emulsifier system composition in Example 2 can give the processed cheese a better texture, and the sensory evaluation results are significantly better. During the storage process, the overall score of the product of Example 2 decreased from 100 points to 89 points, a decrease of 11%, which is higher than the products of Examples 1 and 3 and the products of Comparative Examples 1-4. The processed cheese of Comparative Example 2 used hydrated material and had the lightest color. Comparative Examples 1 and 3 used other emulsifier systems or tea extracts from other tea sources, and the texture of the processed cheese changed and off-flavors were produced.

[0101] Table 2 Sensory evaluation during the shelf life of low-temperature storage

[0102]

[0103]

[0104] Experimental Example 2: Determination of Peroxide Value in Processed Cheese

[0105] 1. Experimental materials: Reconstituted cheese from Examples 1-3 and Comparative Examples 1-4.

[0106] 2. Test Method: The processed cheeses from Examples 1-3 and Comparative Examples 1-4 were stored at 4°C, and the peroxide value was measured at different storage times. The peroxide value was determined according to Method I—Titration—of the National Food Safety Standard for Determination of Peroxide Value in Food (GB5009.227—2016).

[0107] Peroxide value determination procedure: Dissolve the sample in a chloroform-glacial acetic acid mixture, add saturated potassium iodide solution and shake well. Let it react in the dark for 3 minutes, then remove it, add 100 mL of water and shake well. Add starch indicator, and titrate with sodium thiosulfate solution until the solution in the iodine flask is clear. Record the amount of standard solution consumed and calculate the peroxide value of the sample. The results are shown in Table 3.

[0108] Table 3. Changes in peroxide value during the shelf life of low-temperature storage.

[0109]

[0110]

[0111] Experiment Example 3: Antibacterial Properties Test of Processed Cheese

[0112] The antibacterial properties of the processed cheeses in each embodiment and comparative example were tested using the following plaque test method:

[0113] Sample preparation: Dissolve 2g of processed cheese samples from Examples 1-3 and Comparative Examples 1-4, which have been stored at 4℃ for different times, in 98ml of deionized water and bring to a final volume for later use.

[0114] The culture medium was prepared in accordance with the GB4789.3 standard for Escherichia coli count. The bacterial strain was activated, the bacterial suspension was prepared, and the suspension was spread and inoculated. Oxford cups (small round tubes) were placed vertically on the surface of the culture medium with the bacterial suspension spread, and pressure was applied to ensure that the rest of the culture medium was in seamless contact. The sample to be tested was added to the cup and incubated at 37°C for 24 hours. The results were observed and the diameter of the inhibition zone was measured.

[0115] The results of the inhibition plaque diameter measurement are shown in Table 4. The results show that the antibacterial effect of oolong tea extract is higher than that of black tea extract. The initial inhibition plaque diameter of the processed cheese sample in Example 2 was 13.2 mm. As the storage time of the processed cheese increased, the content of tea polyphenols decreased, and the antibacterial effect weakened. At the end of the 21-day experiment, the inhibition plaque diameter reached 11.5 mm. The antibacterial effect of the processed cheese showed a certain positive correlation with the content of tea polyphenols. During the shelf life, as the storage time increased, the content of tea polyphenols decreased, and the antibacterial performance of the processed cheese decreased accordingly.

[0116] Table 4. Escherichia coli Antibacterial Test Table

[0117]

[0118] Experiment Example 4: Detection of Tea Polyphenol Content in Processed Cheese

[0119] The polyphenol content in the processed cheese of each embodiment and comparative example was detected using the ferrous tartrate method. The steps are as follows:

[0120] Take 2g of the processed cheese samples from Examples 1-3 and Comparative Examples 1, 3, and 4, which have been stored at 4℃ for different times, dissolve them in 20ml of water, stir well, and bring the volume to 50ml. Measure the polyphenol content.

[0121] Using propyl gallate as the standard, under the conditions of pH 7.5, wavelength 540nm, and 10mm cuvette, the absorbance of 1mg gallopropionic acid is equivalent to the absorbance of 1.5mg tea polyphenols.

[0122] Propyl gallate solution: Weigh 0.5g of propyl gallate, dissolve it in deionized water, and transfer it to a 500mL volumetric flask to prepare a 1mg / mL solution.

[0123] Preparation of ferrous tartrate solution: Weigh 0.1g of ferrous sulfate and 0.5g of potassium sodium tartrate into a beaker, mix them, dissolve them with a small amount of deionized water, stir and make up to 100mL, and store in the dark.

[0124] Preparation of pH 7.5 buffer solution: Weigh 2.969g of disodium hydrogen phosphate, dissolve in deionized water, and dilute to volume in a 250ml volumetric flask to obtain solution A; Weigh 2.2695g of dipotassium hydrogen phosphate, dissolve in deionized water, and dilute to volume in a 250ml volumetric flask to obtain solution B; Mix 85ml of solution A and 15ml of solution B in 100ml of pH 7.5 buffer solution.

[0125] Determination of tea polyphenol content: Take 4 ml of test solution into a 25 mL volumetric flask, add 4 mL of deionized water and 5 mL of ferrous tartrate, dilute with pH 7.5 buffer to 25 mL, and detect at 540 nm using a spectrophotometer and a 10 mm cuvette. Use deionized water as a reference solution, perform three parallel tests and take the average value.

[0126] The results of the tea polyphenol content test are shown in Table 5. The results show that the source of tea leaves in the tea extract has an impact on the change of tea polyphenol content during the storage period. The composition of the emulsifier not only affects the texture of the processed cheese, but also affects the change of tea polyphenol content during the storage period. In Examples 1-3, the initial amount of tea polyphenols added was 13%. As time went on, the tea polyphenol content decreased, and therefore the antibacterial effect was weakened, which is consistent with the antibacterial performance test results in Experiment 3.

[0127] Table 5 Changes in tea polyphenols during low-temperature storage shelf life.

[0128]

[0129]

[0130] Stability analysis of processed cheese in Experiment Example 5

[0131] 1. Experimental materials: Reconstituted cheese from Examples 1-3 and Comparative Examples 1-4.

[0132] 2. Experimental Methods: The stability of the processed cheeses from Examples 1-3 and Comparative Examples 1-4 was analyzed using a LUMI stability analyzer. The experimental parameters are shown in Table 6, and the results are shown in Table 7. Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown.

[0133] Table 6 Experimental Parameters

[0134] Outline Time interval rotational speed Light factor temperature 100 10s 4000 1.00 25℃

[0135] Table 7 Stability Test Results

[0136] Test group Clarification Index Upper layer precipitation Example 1 0.095 2.9mm Example 2 0.024 0.6mm Example 3 0.064 1.8mm Comparative Example 1 0.420 7.4mm Comparative Example 2 0.544 9.2mm Comparative Example 3 0.307 5.8mm Comparative Example 4 0.124 3.4mm

[0137] The results showed that compared with Comparative Examples 1-4, the processed cheese of Examples 1-3 had better stability, and the phenomenon of fat floating in the product was significantly reduced compared with Comparative Examples 1-4. Among them, the processed cheese of Example 2 had almost no fat floating and sedimentation, and the stability of the system was significantly higher.

[0138] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A prepared cheese, characterized by, Prepared from the following raw materials by weight: raw cheese 14-30 parts, milk raw material 2-4 parts, emulsifier 1-3 parts, tea extract 30-55 parts, oil 20-35 parts, sweetener 1-3 parts, acidity regulator 1-2 parts; The tea extract is oolong tea extract; The content of tea polyphenols in the tea extract is 10-20%; The emulsifier is sodium phosphate dibasic and sodium polyphosphate with a mass ratio of (2-4):1; Alternatively, the emulsifier is sodium hexametaphosphate, sodium polyphosphate and sodium phosphate dibasic with a mass ratio of (1.2-2):1:(0.4-1); In the preparation method of the processed cheese, the tea extract is used to replace water to process the raw materials of the processed cheese.

2. The reconstituted cheese according to claim 1, characterized in that, The preparation method of the tea extract comprises: mixing tea leaves with water, then extracting at 65-95℃ for 1-2h, and collecting the extract by solid-liquid separation.

3. The reconstituted cheese according to claim 2, characterized in that, The mixing mass ratio of tea leaves to water is 1:(10-40).

4. The processed cheese according to any one of claims 1 to 3, characterized in that, In the processed cheese, the mass ratio of protein to fat is (0.5-0.8):

1.

5. The process of claim 4 wherein, In the processed cheese, the mass percentage of protein is 12%-25%, and the mass percentage of fat is 16%-30%.

6. The processed cheese according to any one of claims 1 to 3, 5, wherein The mass ratio of the emulsifier to tea polyphenols is (1-2):(4-8).

7. The processed cheese according to any one of claims 1 to 3, 5, wherein The raw cheese is any one or a combination of at least two selected from the group consisting of gouda cheese, cheddar cheese and grana padano cheese; and / or, The oil is any one or a combination of at least two selected from the group consisting of whipped cream and butter; and / or, The milk raw material is any one or a combination of at least two selected from the group consisting of whey protein powder, milk powder and sodium caseinate.

8. The processed cheese according to any one of claims 1 to 3, 5, wherein The sweetener is any one or a combination of at least two selected from the group consisting of white granulated sugar, cyclamate, chloro sucrose, aspartame, steviol glycoside and mogroside; and / or, the acidity regulator is any one or a combination of at least two selected from the group consisting of citric acid and lactic acid.

9. Process for the preparation of a processed cheese according to any one of claims 1 to 8, characterized in that, The method comprises: mixing raw cheese, oil and 30-40% of the total mass of tea extract at 60-95℃ to obtain a first raw material mixture; Mixing the first raw material mixture with the remaining tea extract, milk raw material, sweetener and acidity regulator, and then mixing with the emulsifier to obtain a second raw material mixture; Cooking the second raw material mixture at 90-98℃ for 10-20min.

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