Cheese stored at normal temperature and preparation method thereof
By using a mixed bacterial agent of Streptococcus thermophilus, Lactobacillus casei and Lactobacillus plantarum and polyvinylidene fluoride microfiltration membrane treatment, combined with drying and electron beam radiation, the problem of single taste and short storage time of cheese is solved, and cheese is achieved diversity and long-term storage.
Patent Information
- Application Number
- CN202411615290.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-01-10
AI Technical Summary
The limitation of fermentation agents for existing cheeses leads to a single taste and flavor, which is difficult to meet the needs of different users, and microorganisms are prone to breeding during storage at room temperature, shortening storage time.
Fermentation is carried out using a mixed bacterial agent of Streptococcus thermophilus, Lactobacillus casei and Lactobacillus plantarum, and bacteria and impurities in milk are removed through a polyvinylidene fluoride microfiltration membrane, combined with drying and electron beam radiation treatment to extend the storage time of cheese .
It realizes the complex flavor and taste diversity of cheese, improves the preparation quality, and effectively extends the storage time of cheese at room temperature.
Smart Images
Figure CN119279028A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of food processing, in particular to cheese stored at room temperature and a preparation method thereof. Background Art
[0002] Cheese, also known as cottage cheese or cheese, is a fermented milk product. Its properties are similar to common yogurt. Both are made through a fermentation process and contain lactic acid bacteria that can be used for health. However, the concentration of cheese is higher than that of yogurt, which is similar to solid food, and its nutritional value is therefore richer. Cheese is rich in nutrients such as protein, calcium, phosphorus, vitamin B12 and fat. After use, it can regulate the nutritional balance of the human body and is a popular edible product. The existing cheese is limited by the fermentation bacteria, resulting in a single taste and flavor after fermentation, which is difficult to meet the edible needs of different users and limits the audience range of cheese. At the same time, it is difficult to fully remove the miscellaneous bacteria remaining in the raw materials before fermentation. The residual miscellaneous bacteria will inhibit the fermentation process of lactic acid bacteria in the later stage, thereby affecting the preparation quality of the cheese. In addition, the sterilization step after preparation is simple, and the microorganisms remaining in the packaging bag are easy to breed and develop at room temperature, thereby shortening the storage time of cheese at room temperature. Therefore, it is necessary to design a room temperature storage cheese and a preparation method thereof. Summary of the invention
[0003] The object of the present invention is to provide a cheese stored at room temperature and a preparation method thereof, so as to solve the problems raised in the above background technology.
[0004] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a cheese for storage at room temperature, the formula of which includes: low-fat milk, mixed fermentation bacteria, rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt; the weight proportions of each component are: 80 to 95 parts of low-fat milk, 1 to 2 parts of mixed fermentation bacteria, 0.05 to 0.1 parts of rennet, 0.05 to 0.1 parts of potassium sorbate, 0.05 to 0.1 parts of sodium benzoate, 0.05 to 0.1 parts of butylated hydroxytoluene and 2 to 4 parts of salt.
[0005] As a further technical solution of the present invention, the mixed fermentation bacteria agent contains three lactic acid bacteria, namely, Streptococcus thermophilus, Lactobacillus casei and Lactobacillus plantarum, and the mixing ratio of Streptococcus thermophilus, Lactobacillus casei and Lactobacillus plantarum is 1:1:1.
[0006] As a further technical solution of the present invention, the preparation process of the mixed fermentation bacterial agent is as follows: first, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum strains are selected for standby use, then the thermophilic streptococcus strain is inoculated on an agar medium, and the lactobacillus casei and lactobacillus plantarum strains are respectively inoculated on an MRS medium, and cultured at a temperature of 37°C for 24 to 48 hours after inoculation, and the culture medium is expanded at a temperature of 37°C for expansion culture after culture, and the expansion culture is expanded until the OD600 detection amount reaches 1.0 to 1.5; after the expansion culture is completed, they are respectively placed in a centrifuge, and the centrifuge is centrifuged at 4000rpm for 10 to 12min and then the bacterial precipitates are collected, and then the bacterial precipitates are washed 2 to 3 times with sterile physiological saline or buffer to remove the culture medium residue, and then the three bacterial precipitates are mixed and added with 0.2% to 0.4% skim milk powder as a protective agent, and pre-frozen at a temperature of -40°C for 4 hours, and then vacuum dried at a temperature of -40°C to -50°C for 24 to 48 hours, and a mixed fermentation bacterial agent is obtained after vacuum drying.
[0007] A method for preparing cheese stored at room temperature, comprising the following steps: step 1, taking materials; step 2, pretreatment; step 3, microfiltration treatment; step 4, fermentation and coagulation; step 5, molding processing; step 6, drying and packaging; step 7, post-treatment; In the above step 1, 80-95 parts of low-fat milk, 1-2 parts of mixed fermentation bacteria, 0.05-0.1 parts of rennet, 0.05-0.1 parts of potassium sorbate, 0.05-0.1 parts of sodium benzoate, 0.05-0.1 parts of butylated hydroxytoluene and 2-4 parts of salt are weighed according to the weight of each group and set aside; In the above step 2, the low-fat milk prepared in the above step 1 is placed in a treatment tank, and then the temperature of the treatment tank is increased and the treatment tank is kept at a constant temperature, and then cooled to obtain pre-treated milk for standby use; In the above step 3, the pre-treated milk prepared in the above step 2 is pre-filtered using a pre-filter, and the fibers and impurities remaining in the low-fat milk are removed during the pre-filtration process. Then, the low-fat milk after the pre-filtration is micro-filtered using a microfiltration membrane. During the process, the pre-treated milk passes through the microfiltration membrane under pressure, so that water, lactose, minerals and part of the protein pass through the membrane pores to form a permeate, and at the same time, larger particles are retained on the membrane surface to form a concentrated solution, which is extracted separately for later use; In the above step 4, the permeate prepared in the above step 3 is placed in a fermentation tank, and then the mixed fermentation agent prepared in the above step 1 is added to the fermentation tank, and then constant temperature fermentation is carried out in the fermentation tank, and coagulation is carried out after constant temperature fermentation, and curd is obtained after coagulation for use; In the step 5, the curd prepared in the step 4 is cut and put into a blender after cutting, and then the rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt prepared in the step 1 are added into the blender, and then the blender is continuously stirred, and after continuous stirring, the curd is put into a mold and pressed into a cheese block for later use; In the above step 6, the cheese block obtained in the above step 5 is placed in a drying oven, and then dried at a constant temperature in the drying oven. After drying, the cheese block is taken out and vacuum-packed in a sterile room. After vacuum packaging, the packaged cheese is obtained and set aside; In the above step 7, the packaged cheese prepared in the above step 6 is sterilized in separate bags, and then heat-treated, and then cooled to obtain cheese for storage at room temperature.
[0008] As a further technical solution of the present invention, in the step 2, the temperature increase rate when increasing the temperature of the treatment pool is 5 to 8°C / min, and the temperature of the treatment pool needs to be increased to 62 to 63°C. The temperature in the treatment pool during the constant temperature standing process is 62 to 63°C, and the constant temperature standing time is 30 to 35 minutes. The cooling rate during the cooling process is 12 to 15°C / min, and the cooling needs to reduce the temperature to 4 to 4.5°C.
[0009] As a further technical solution of the present invention, in the step three, the mesh size of the pre-filter is 100-200 μm, the microfiltration membrane material used in the microfiltration treatment process is polyvinylidene fluoride, and the pore size of the membrane on the microfiltration membrane is 0.1-10 μm, and the temperature during the microfiltration treatment is 21-35°C.
[0010] As a further technical solution of the present invention, in the step four, the temperature in the fermentation tank during the constant temperature fermentation process is 30-42°C, and the constant temperature fermentation time is 120-480min, the stirring speed of the stirring rack in the fermentation tank during the constant temperature fermentation process is 10-15r / min, and the pH value of the liquid in the fermentation tank after the constant temperature fermentation is 4.6-5.0; during coagulation, the temperature in the fermentation tank is 30-32°C, and the coagulation is performed until the liquid completely becomes a stable block.
[0011] As a further technical solution of the present invention, in the step 5, the curd needs to be cut into square blocks of 2 to 4 cm, the temperature in the mixer during continuous stirring is 40 to 45°C, the stirring speed during continuous stirring is 25 to 40 r / min, and the continuous stirring time is 25 to 30 min; the pressure applied during the pressing process is 1 to 1.6 kg / cm 2 .
[0012] As a further technical solution of the present invention, in step six, the temperature in the drying oven during the constant temperature drying process is 30-40° C., and the constant temperature drying time is 760-1500 min.
[0013] As a further technical solution of the present invention, in step seven, an electron beam with a dose of 10 to 20 kGy is used for continuous radiation for 30 to 40 minutes during the bag sterilization process, and the heat treatment requires the packaged cheese to be placed at a temperature of 60 to 65° C. for continuous standing for 30 to 35 minutes.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the cheese stored at room temperature and the preparation method thereof, by fermenting milk with a mixed bacterial agent prepared by using three lactic acid bacteria, namely, thermophilic streptococci, lactobacillus casei and lactobacillus plantarum, achieves a mutualistic symbiotic effect in the fermentation process, and can obtain a more complex and rich flavor and taste after fermentation, which can meet the edible needs of different users and expand the audience range of cheese; before processing, the milk is microfiltered using a microfiltration membrane prepared by polyvinylidene fluoride to remove bacteria and impurities in the milk, while retaining protein and fat, thereby improving the purity and quality of the raw materials and ensuring the preparation quality of the cheese; after pressing and molding, moisture is removed by drying, and after vacuum packaging, the bags are irradiated with electron beams, and combined with heat treatment, the microorganisms inside the vacuum bag are effectively killed while maintaining the flavor and texture of the cheese, thereby extending the storage time of the cheese at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION
[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0017] See also Figure 1 , the present invention provides a technical solution: Example 1
[0018] A cheese stored at room temperature, the formula of which includes: low-fat milk, mixed fermentation bacteria, rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt; the weight proportions of the components are: 95 parts of low-fat milk, 2 parts of mixed fermentation bacteria, 0.1 parts of rennet, 0.1 parts of potassium sorbate, 0.1 parts of sodium benzoate, 0.1 parts of butylated hydroxytoluene and 4 parts of salt; the mixed fermentation bacteria contains three lactic acid bacteria, namely, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum, and the mixing ratio of thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum is 1:1:1; the preparation process of the mixed fermentation bacteria is: firstly, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum strains are selected for standby use, and then the thermophilic streptococcus strains are inoculated onto an agar medium. , and inoculate Lactobacillus casei and Lactobacillus plantarum strains onto MRS culture medium, respectively. After inoculation, culture them at 37°C for 48 hours. After culture, expand the culture medium at 37°C until the OD600 detection value reaches 1.5. After the expansion culture is completed, put them into a centrifuge respectively, and centrifuge them at 4000rpm for 12min to collect the bacterial precipitates, and then wash the bacterial precipitates 3 times with sterile saline or buffer to remove the culture medium residues, and then mix the three bacterial precipitates and add 0.4% skim milk powder as a protective agent, and pre-freeze them at -40°C for 4 hours, and then vacuum dry them at -50°C for 48 hours to obtain a mixed fermentation bacterial agent.
[0019] A method for preparing cheese stored at room temperature, comprising the following steps: step 1, taking materials; step 2, pretreatment; step 3, microfiltration treatment; step 4, fermentation and coagulation; step 5, molding processing; step 6, drying and packaging; step 7, post-treatment; In the above step 1, 95 parts of low-fat milk, 2 parts of mixed fermentation bacteria, 0.1 parts of rennet, 0.1 parts of potassium sorbate, 0.1 parts of sodium benzoate, 0.1 parts of butylated hydroxytoluene and 4 parts of salt are weighed according to the weight of each group and set aside; In the above step 2, the low-fat milk prepared in the above step 1 is placed in a treatment tank, and then the temperature of the treatment tank is increased and kept at a constant temperature. After standing, the pre-treated milk is cooled to obtain a pre-treated milk for standby use; when the temperature of the treatment tank is increased, the temperature increase rate is 8°C / min, and the temperature of the treatment tank needs to be increased to 63°C. During the constant temperature standing process, the temperature in the treatment tank is 63°C, and the constant temperature standing time is 35 minutes. The cooling rate during the cooling process is 15°C / min, and the cooling needs to reduce the temperature to 4.5°C; In the above step three, a pre-filter is used to pre-filter the pre-treated milk prepared in the above step two, and the fibers and impurities remaining in the low-fat milk are removed during the pre-filtration process. Then, a microfiltration membrane is used to microfilter the pre-filtered low-fat milk. During the process, the pre-treated milk passes through the microfiltration membrane under pressure, so that water, lactose, minerals and part of the protein pass through the membrane pores to form a permeate, and at the same time, larger particles are retained on the membrane surface to form a concentrated solution, which is extracted separately for later use; the mesh size of the sieve in the pre-filter is 200 μm, the microfiltration membrane material used in the microfiltration process is polyvinylidene fluoride, and the pore size of the membrane pore on the microfiltration membrane is 10 μm, and the temperature during the microfiltration process is 35°C; wherein in the above step 4, the permeate prepared in the above step 3 is placed in a fermentation tank, and then the mixed fermentation agent prepared in the above step 1 is added to the fermentation tank, and then constant temperature fermentation is carried out in the fermentation tank, and coagulation is carried out after constant temperature fermentation, and curd is obtained after coagulation for use; during the constant temperature fermentation process, the temperature in the fermentation tank is 42°C, and the constant temperature fermentation time is 480min, the stirring speed of the stirring rack in the fermentation tank during the constant temperature fermentation process is 15r / min, and the pH value of the liquid in the fermentation tank after constant temperature fermentation is 5.0; during coagulation, the temperature in the fermentation tank is 32°C, and the coagulation is carried out until the liquid completely becomes a stable block; In the above step 5, the curd prepared in the above step 4 is cut and put into a blender after cutting, and then the rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt prepared in step 1 are added to the blender, and then the blender is continuously stirred, and after continuous stirring, the blender is placed in a mold and pressed to obtain cheese blocks for later use; the curd needs to be cut into 4 cm square blocks, the temperature in the blender during continuous stirring is 45°C, the stirring speed during continuous stirring is 40 r / min, and the continuous stirring time is 30 min; the pressure applied during the pressing process is 1.6 kg / cm 2 ; In the above step 6, the cheese block obtained in the above step 5 is placed in a drying oven, and then dried at a constant temperature in the drying oven. After drying, the cheese block is taken out and vacuum-packed in a sterile room. After vacuum packaging, the packaged cheese is obtained for standby use; the temperature in the drying oven during the constant temperature drying process is 40° C., and the constant temperature drying time is 1500 min; In the above step seven, the packaged cheese prepared in the above step six is sterilized in bags, and then heat treated, and then cooled to obtain cheese for storage at room temperature; during the bag sterilization process, an electron beam with a dose of 20 kGy is used for continuous radiation for 40 minutes, and the heat treatment requires the packaged cheese to be placed at a temperature of 65°C for continuous standing for 35 minutes. Example 2
[0020] A cheese stored at room temperature, the formula of which includes: low-fat milk, mixed fermentation bacteria, rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt; the weight proportions of the components are: 80 parts of low-fat milk, 1 part of mixed fermentation bacteria, 0.05 parts of rennet, 0.05 parts of potassium sorbate, 0.05 parts of sodium benzoate, 0.05 parts of butylated hydroxytoluene and 2 parts of salt; the mixed fermentation bacteria contains three lactic acid bacteria, namely, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum, and the mixing ratio of thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum is 1:1:1; the preparation process of the mixed fermentation bacteria is: firstly, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum strains are selected for standby use, then the thermophilic streptococcus strains are inoculated into agar culture medium, and the mixture is stirred for 3 hours. On the basis, Lactobacillus casei and Lactobacillus plantarum strains were inoculated into MRS culture medium respectively, and cultured at 37°C for 24 hours after inoculation. After culture, the culture medium was expanded at 37°C for expansion culture until the OD600 detection value reached 1.0; after the expansion culture was completed, they were placed in a centrifuge respectively, and the centrifuge was centrifuged at 4000rpm for 10min and then the bacterial precipitates were collected, and then the bacterial precipitates were washed twice with sterile saline or buffer solution to remove the culture medium residues, and then the three bacterial precipitates were mixed and added with 0.2% skim milk powder as a protective agent, and pre-frozen at -40°C for 4 hours, and then vacuum dried at -40°C for 24 hours to obtain a mixed fermentation bacterial agent after vacuum drying.
[0021] A method for preparing cheese stored at room temperature, comprising the following steps: step 1, taking materials; step 2, pretreatment; step 3, microfiltration treatment; step 4, fermentation and coagulation; step 5, molding processing; step 6, drying and packaging; step 7, post-treatment; In the above step 1, 80 parts of low-fat milk, 1 part of mixed fermentation bacteria, 0.05 parts of rennet, 0.05 parts of potassium sorbate, 0.05 parts of sodium benzoate, 0.05 parts of butylated hydroxytoluene and 2 parts of salt are weighed according to the weight of each group and set aside; In the above step 2, the low-fat milk prepared in the above step 1 is placed in a treatment tank, and then the temperature of the treatment tank is increased and kept at a constant temperature. After standing, the pre-treated milk is obtained by cooling down for standby; when the temperature of the treatment tank is increased, the temperature increase rate is 5°C / min, and the temperature of the treatment tank needs to be increased to 62°C. During the constant temperature standing process, the temperature in the treatment tank is 623°C, and the constant temperature standing time is 30min. The cooling rate during the cooling process is 12°C / min, and the cooling needs to reduce the temperature to 4°C; In the above step three, a pre-filter is used to pre-filter the pre-treated milk prepared in the above step two, and the fibers and impurities remaining in the low-fat milk are removed during the pre-filtration process. Then, a microfiltration membrane is used to microfilter the pre-filtered low-fat milk. During the process, the pre-treated milk passes through the microfiltration membrane under pressure, so that water, lactose, minerals and part of the protein pass through the membrane pores to form a permeate, and at the same time, larger particles are retained on the membrane surface to form a concentrated solution, which is extracted separately for later use; the mesh size of the sieve in the pre-filter is 100 μm, the microfiltration membrane material used in the microfiltration process is polyvinylidene fluoride, and the pore size of the membrane pore on the microfiltration membrane is 0.1 μm, and the temperature during the microfiltration process is 21°C; wherein in the above step 4, the permeate prepared in the above step 3 is placed in a fermentation tank, and then the mixed fermentation agent prepared in the above step 1 is added to the fermentation tank, and then constant temperature fermentation is carried out in the fermentation tank, and coagulation is carried out after constant temperature fermentation, and curd is obtained after coagulation for use; during the constant temperature fermentation process, the temperature in the fermentation tank is 30°C, and the constant temperature fermentation time is 120min, the stirring speed of the stirring rack in the fermentation tank during the constant temperature fermentation process is 10r / min, and the pH value of the liquid in the fermentation tank after constant temperature fermentation is 4.6; during coagulation, the temperature in the fermentation tank is 30°C, and the coagulation is carried out until the liquid completely becomes a stable block; In the above step 5, the curd prepared in the above step 4 is cut and put into a blender after cutting, and then the rennet, potassium sorbate, sodium benzoate, butyl hydroxytoluene and salt prepared in step 1 are added to the blender, and then the blender is continuously stirred, and after continuous stirring, the blender is placed in a mold and pressed to obtain cheese blocks for later use; the curd needs to be cut into 2 cm square blocks, the temperature in the blender during continuous stirring is 40°C, the stirring speed during continuous stirring is 25 r / min, and the continuous stirring time is 25 min; the pressure applied during the pressing process is 1 kg / cm 2 ; In the above step 6, the cheese block obtained in the above step 5 is placed in a drying oven, and then is dried at a constant temperature in the drying oven. After drying, the cheese block is taken out and vacuum-packed in a sterile room. After vacuum packaging, the packaged cheese is obtained for standby use; the temperature in the drying oven during the constant temperature drying process is 30° C., and the constant temperature drying time is 760 min; In the above step seven, the packaged cheese prepared in the above step six is sterilized in bags, and then heat treated, and then cooled to obtain cheese for storage at room temperature; during the bag sterilization process, an electron beam with a dose of 10 kGy is used for continuous radiation for 30 minutes, and the heat treatment requires the packaged cheese to be placed at a temperature of 60°C for continuous standing for 30 minutes. Example 3
[0022] A cheese stored at room temperature, the formula of which includes: low-fat milk, mixed fermentation bacteria, rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt; the weight proportions of the components are: 95 parts of low-fat milk, 1 part of mixed fermentation bacteria, 0.1 part of rennet, 0.05 parts of potassium sorbate, 0.1 parts of sodium benzoate, 0.05 parts of butylated hydroxytoluene and 4 parts of salt; the mixed fermentation bacteria contains three lactic acid bacteria, namely, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum, and the mixing ratio of thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum is 1:1:1; the preparation process of the mixed fermentation bacteria is: firstly, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum strains are selected for standby use, and then the thermophilic streptococcus strains are inoculated into an agar medium. and inoculate Lactobacillus casei and Lactobacillus plantarum strains onto MRS culture medium, respectively, and culture them at 37°C for 48h after inoculation. After culture, expand the culture medium at 37°C until the OD600 detection value reaches 1.0; after the expansion culture is completed, put them into a centrifuge respectively, and centrifuge them at 4000rpm for 12min, then collect the bacterial precipitates, and then wash the bacterial precipitates twice with sterile saline or buffer solution to remove the culture medium residues, and then mix the three bacterial precipitates and add 0.4% skim milk powder as a protective agent, and pre-freeze them at -40°C for 4 hours, and then vacuum dry them at -40°C for 48h to obtain a mixed fermentation bacterial agent.
[0023] A method for preparing cheese stored at room temperature, comprising the following steps: step 1, taking materials; step 2, pretreatment; step 3, microfiltration treatment; step 4, fermentation and coagulation; step 5, molding processing; step 6, drying and packaging; step 7, post-treatment; In the above step 1, 95 parts of low-fat milk, 1 part of mixed fermentation bacteria, 0.1 part of rennet, 0.05 parts of potassium sorbate, 0.1 parts of sodium benzoate, 0.05 parts of butylated hydroxytoluene and 4 parts of salt are weighed according to the weight of each group and set aside; In the above step 2, the low-fat milk prepared in the above step 1 is placed in a treatment tank, and then the temperature of the treatment tank is increased and kept at a constant temperature. After standing, the pre-treated milk is obtained by cooling down for standby; when the temperature of the treatment tank is increased, the temperature increase rate is 8°C / min, and the temperature of the treatment tank needs to be increased to 62°C. During the constant temperature standing process, the temperature in the treatment tank is 63°C, and the constant temperature standing time is 30 minutes. The cooling rate during the cooling process is 15°C / min, and the cooling needs to reduce the temperature to 4.5°C; In the above step three, a pre-filter is used to pre-filter the pre-treated milk prepared in the above step two, and the fibers and impurities remaining in the low-fat milk are removed during the pre-filtration process. Then, a microfiltration membrane is used to microfilter the pre-filtered low-fat milk. During the process, the pre-treated milk passes through the microfiltration membrane under pressure, so that water, lactose, minerals and part of the protein pass through the membrane pores to form a permeate, and at the same time, larger particles are retained on the membrane surface to form a concentrated solution, which is extracted separately for later use; the mesh size of the sieve in the pre-filter is 100 μm, the microfiltration membrane material used in the microfiltration process is polyvinylidene fluoride, and the pore size of the membrane pore on the microfiltration membrane is 10 μm, and the temperature during the microfiltration process is 21°C; wherein in the above step 4, the permeate prepared in the above step 3 is placed in a fermentation tank, and then the mixed fermentation agent prepared in the above step 1 is added to the fermentation tank, and then constant temperature fermentation is carried out in the fermentation tank, and coagulation is carried out after the constant temperature fermentation, and curd is obtained after coagulation for use; during the constant temperature fermentation process, the temperature in the fermentation tank is 42°C, and the constant temperature fermentation time is 120min, the stirring speed of the stirring rack in the fermentation tank during the constant temperature fermentation process is 15r / min, and the pH value of the liquid in the fermentation tank after the constant temperature fermentation is 4.6; during the coagulation, the temperature in the fermentation tank is 32°C, and the coagulation is carried out until the liquid completely becomes a stable block; In the above step 5, the curd prepared in the above step 4 is cut and put into a blender after cutting, and then the rennet, potassium sorbate, sodium benzoate, butyl hydroxytoluene and salt prepared in step 1 are added to the blender, and then the blender is continuously stirred, and after continuous stirring, the blender is placed in a mold and pressed to obtain cheese blocks for later use; the curd needs to be cut into 4 cm square blocks, the temperature in the blender during continuous stirring is 40°C, the stirring speed during continuous stirring is 40 r / min, and the continuous stirring time is 25 min; the pressure applied during the pressing process is 1.6 kg / cm 2 ; In the above step 6, the cheese block obtained in the above step 5 is placed in a drying oven, and then dried at a constant temperature in the drying oven. After drying, the cheese block is taken out and vacuum-packed in a sterile room. After vacuum packaging, the packaged cheese is obtained for standby use; the temperature in the drying oven during the constant temperature drying process is 30° C., and the constant temperature drying time is 1500 min; In the above step seven, the packaged cheese prepared in the above step six is sterilized in bags, and then heat treated, and then cooled to obtain cheese for storage at room temperature; during the bag sterilization process, an electron beam with a dose of 10 kGy is used for continuous radiation for 40 minutes, and the heat treatment requires the packaged cheese to be placed at a temperature of 60°C for continuous standing for 35 minutes. Example 4
[0024] A cheese stored at room temperature, the formula of which includes: low-fat milk, mixed fermentation bacteria, rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt; the weight proportions of the components are: 90 parts of low-fat milk, 2 parts of mixed fermentation bacteria, 0.07 parts of rennet, 0.06 parts of potassium sorbate, 0.09 parts of sodium benzoate, 0.08 parts of butylated hydroxytoluene and 3 parts of salt; the mixed fermentation bacteria contains three lactic acid bacteria, namely, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum, and the mixing ratio of thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum is 1:1:1; the preparation process of the mixed fermentation bacteria is: firstly, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum strains are selected for standby use, then the thermophilic streptococcus strains are inoculated into agar culture medium, and the mixture is stirred for 3 hours. On the basis, Lactobacillus casei and Lactobacillus plantarum strains were inoculated into MRS culture medium respectively, and cultured at 37°C for 36 hours after inoculation. After culture, the culture medium was expanded at 37°C until the OD600 detection value reached 1.2; after the expansion culture was completed, they were placed in a centrifuge respectively, and the centrifuge was centrifuged at 4000rpm for 11min to collect the bacterial precipitates, and then the bacterial precipitates were washed twice with sterile saline or buffer to remove the culture medium residues, and then the three bacterial precipitates were mixed and added with 0.3% skim milk powder as a protective agent, and pre-frozen at -40°C for 4 hours, and then vacuum dried at -45°C for 36 hours to obtain a mixed fermentation bacterial agent.
[0025] A method for preparing cheese stored at room temperature, comprising the following steps: step 1, taking materials; step 2, pretreatment; step 3, microfiltration treatment; step 4, fermentation and coagulation; step 5, molding processing; step 6, drying and packaging; step 7, post-treatment; In the above step 1, 90 parts of low-fat milk, 2 parts of mixed fermentation bacteria, 0.07 parts of rennet, 0.06 parts of potassium sorbate, 0.09 parts of sodium benzoate, 0.08 parts of butylated hydroxytoluene and 3 parts of salt are weighed according to the weight of each group and set aside; In the above step 2, the low-fat milk prepared in the above step 1 is placed in a treatment tank, and then the temperature of the treatment tank is increased and kept at a constant temperature. After standing, the pre-treated milk is obtained by cooling down for standby; when the temperature of the treatment tank is increased, the temperature increase rate is 7°C / min, and the temperature of the treatment tank needs to be increased to 62°C. During the constant temperature standing process, the temperature in the treatment tank is 63°C, and the constant temperature standing time is 32 minutes. The cooling rate during the cooling process is 14°C / min, and the cooling needs to reduce the temperature to 4.2°C; In the above step three, a pre-filter is used to pre-filter the pre-treated milk prepared in the above step two, and fibers and impurities remaining in the low-fat milk are removed during the pre-filtration process. Then, a microfiltration membrane is used to microfilter the pre-filtered low-fat milk. During the process, the pre-treated milk passes through the microfiltration membrane under pressure, so that water, lactose, minerals and part of the protein pass through the membrane pores to form a permeate, and larger particles are retained on the membrane surface to form a concentrated solution, which is extracted separately for later use; the mesh size of the sieve in the pre-filter is 150 μm, the microfiltration membrane material used in the microfiltration process is polyvinylidene fluoride, and the pore size of the membrane pore on the microfiltration membrane is 5 μm, and the temperature during the microfiltration process is 30°C; wherein in the above step 4, the permeate prepared in the above step 3 is placed in a fermentation tank, and then the mixed fermentation agent prepared in the above step 1 is added to the fermentation tank, and then constant temperature fermentation is carried out in the fermentation tank, and coagulation is carried out after the constant temperature fermentation, and curd is obtained after coagulation for use; during the constant temperature fermentation process, the temperature in the fermentation tank is 36°C, and the constant temperature fermentation time is 360min, the stirring speed of the stirring rack in the fermentation tank during the constant temperature fermentation process is 12r / min, and the pH value of the liquid in the fermentation tank after the constant temperature fermentation is 4.8; during the coagulation, the temperature in the fermentation tank is 31°C, and the coagulation is carried out until the liquid completely becomes a stable block; In the above step 5, the curd prepared in the above step 4 is cut and put into a blender after cutting, and then the rennet, potassium sorbate, sodium benzoate, butyl hydroxytoluene and salt prepared in step 1 are added to the blender, and then the blender is continuously stirred, and after continuous stirring, the blender is placed in a mold and pressed to obtain cheese blocks for later use; the curd needs to be cut into 3 cm square blocks, the temperature in the blender during continuous stirring is 42°C, the stirring speed during continuous stirring is 36 r / min, and the continuous stirring time is 27 min; the pressure applied during the pressing process is 1.4 kg / cm 2 ; In the above step 6, the cheese block obtained in the above step 5 is placed in a drying oven, and then dried at a constant temperature in the drying oven. After drying, the cheese block is taken out and vacuum-packed in a sterile room. After vacuum packaging, the packaged cheese is obtained for standby use; the temperature in the drying oven during the constant temperature drying process is 36° C., and the constant temperature drying time is 800 min; In the above step seven, the packaged cheese prepared in the above step six is sterilized in bags, and then heat treated, and then cooled to obtain cheese for storage at room temperature; during the bag sterilization process, an electron beam with a dose of 15 kGy is used for continuous radiation for 35 minutes, and the heat treatment requires the packaged cheese to be placed at a temperature of 62°C for continuous standing for 32 minutes.
[0026] The performance of the room temperature stored cheese obtained in the above examples was tested and compared with the common cheese on the market. The results are shown in the following table:
[0027] Based on the above, the advantages of the present invention are that the present invention uses a mixed bacterial agent prepared from three lactic acid bacteria, namely, thermophilic Streptococcus, Lactobacillus casei and Lactobacillus plantarum, to ferment milk, which has a mutualistic symbiotic effect during the fermentation process, and can obtain a more complex and rich flavor and taste after fermentation, which can meet the edible needs of different users and expand the audience range of cheese; before processing, a microfiltration membrane prepared from polyvinylidene fluoride is used to microfilter the milk to remove bacteria and impurities in the milk, while retaining protein and fat, thereby improving the purity and quality of the raw materials and ensuring the preparation quality of the cheese; after pressing and molding, moisture is removed by drying, and after vacuum packaging, the bags are irradiated with electrons, and heat treatment is combined to effectively kill microorganisms inside the vacuum bag while maintaining the flavor and texture of the cheese, thereby extending the storage time of the cheese at room temperature.
[0028] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.
Claims
1. A cheese for storage at room temperature, the formula comprising: Low-fat milk, mixed fermentation bacteria, rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt; the characteristics are that the weight proportions of the components are: 80-95 parts of low-fat milk, 1-2 parts of mixed fermentation bacteria, 0.05-0.1 parts of rennet, 0.05-0.1 parts of potassium sorbate, 0.05-0.1 parts of sodium benzoate, 0.05-0.1 parts of butylated hydroxytoluene and 2-4 parts of salt.
2. The cheese stored at room temperature according to claim 1, characterized in that: The mixed fermentation bacterial agent contains three lactic acid bacteria, namely, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum, and the mixing ratio of thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum is 1:1:
1.
3. The cheese stored at room temperature according to claim 2, characterized in that: The preparation process of the mixed fermentation bacterial agent is as follows: firstly, thermophilic streptococcus, lactobacillus casei and lactobacillus plantarum strains are selected for standby use; then, the thermophilic streptococcus strain is inoculated on an agar medium, and the lactobacillus casei and lactobacillus plantarum strains are respectively inoculated on an MRS medium; after inoculation, the strains are cultured at a temperature of 37°C for 24 to 48 hours; after culture, the culture medium is expanded and cultured at a temperature of 37°C until the OD600 detection amount reaches 1.0 to 1.5; after the expansion culture is completed, the strains are respectively placed in a centrifuge, and the centrifuge is centrifuged at 4000rpm for 10 to 12 minutes, and then bacterial precipitates are collected; then, the bacterial precipitates are washed 2 to 3 times with sterile physiological saline or buffer solution, and the culture medium residue is removed; then, the three bacterial precipitates are mixed, 0.2% to 0.4% skim milk powder is added as a protective agent, and the mixture is pre-frozen at a temperature of -40°C for 4 hours, and then vacuum dried at a temperature of -40°C to -50°C for 24 to 48 hours, and the mixed fermentation bacterial agent is obtained after vacuum drying.
4. A method for preparing cheese stored at room temperature, comprising the following steps: Step 1, material collection; Step 2, pretreatment; Step 3, microfiltration treatment; Step 4, fermentation and coagulation; Step 5, molding and processing; Step 6, drying and packaging; Step 7, post-treatment; It is characterized by: In the above step 1, 80-95 parts of low-fat milk, 1-2 parts of mixed fermentation bacteria, 0.05-0.1 parts of rennet, 0.05-0.1 parts of potassium sorbate, 0.05-0.1 parts of sodium benzoate, 0.05-0.1 parts of butylated hydroxytoluene and 2-4 parts of salt are weighed according to the weight of each group and set aside; In the above step 2, the low-fat milk prepared in the above step 1 is placed in a treatment tank, and then the temperature of the treatment tank is increased and the treatment tank is kept at a constant temperature, and then cooled to obtain pre-treated milk for standby use; In the above step 3, the pre-treated milk prepared in the above step 2 is pre-filtered using a pre-filter, and the fibers and impurities remaining in the low-fat milk are removed during the pre-filtration process. Then, the low-fat milk after the pre-filtration is micro-filtered using a microfiltration membrane. During the process, the pre-treated milk passes through the microfiltration membrane under pressure, so that water, lactose, minerals and part of the protein pass through the membrane pores to form a permeate, and at the same time, larger particles are retained on the membrane surface to form a concentrated solution, which is extracted separately for later use; In the above step 4, the permeate prepared in the above step 3 is placed in a fermentation tank, and then the mixed fermentation agent prepared in the above step 1 is added to the fermentation tank, and then constant temperature fermentation is carried out in the fermentation tank, and coagulation is carried out after constant temperature fermentation, and curd is obtained after coagulation for use; In the step 5, the curd prepared in the step 4 is cut and put into a blender after cutting, and then the rennet, potassium sorbate, sodium benzoate, butylated hydroxytoluene and salt prepared in the step 1 are added into the blender, and then the blender is continuously stirred, and after continuous stirring, the curd is put into a mold and pressed into a cheese block for later use; In the above step 6, the cheese block obtained in the above step 5 is placed in a drying oven, and then dried at a constant temperature in the drying oven. After drying, the cheese block is taken out and vacuum-packed in a sterile room. After vacuum packaging, the packaged cheese is obtained and set aside; In the above step 7, the packaged cheese prepared in the above step 6 is sterilized in separate bags, and then heat-treated, and then cooled to obtain cheese for storage at room temperature.
5. The method for preparing cheese stored at room temperature according to claim 4, characterized in that: In the step 2, when the temperature of the treatment pool is increased, the temperature increase rate is 5 to 8°C / min, and the temperature of the treatment pool needs to be increased to 62 to 63°C. During the constant temperature standing process, the temperature in the treatment pool is 62 to 63°C, and the constant temperature standing time is 30 to 35 minutes. During the cooling process, the cooling rate is 12 to 15°C / min, and the cooling needs to reduce the temperature to 4 to 4.5°C.
6. The method for preparing cheese stored at room temperature according to claim 4, characterized in that: In the step three, the mesh size of the pre-filter is 100-200 μm, the microfiltration membrane used in the microfiltration process is made of polyvinylidene fluoride, and the pore size of the membrane on the microfiltration membrane is 0.1-10 μm, and the temperature during the microfiltration process is 21-35°C.
7. The method for preparing cheese stored at room temperature according to claim 4, characterized in that: In the step 4, the temperature in the fermentation tank is 30-42°C during the constant temperature fermentation process, and the constant temperature fermentation time is 120-480 min. The stirring speed of the stirring rack in the fermentation tank is 10-15 r / min during the constant temperature fermentation process. After the constant temperature fermentation, the pH value of the liquid in the fermentation tank is 4.6-5.0; during coagulation, the temperature in the fermentation tank is 30-32°C, and the coagulation is performed until the liquid completely becomes a stable block.
8. The method for preparing cheese stored at room temperature according to claim 4, characterized in that: In the step 5, the curd needs to be cut into square blocks of 2 to 4 cm. During the continuous stirring process, the temperature in the mixer is 40 to 45° C., the stirring speed during the continuous stirring is 25 to 40 r / min, and the continuous stirring time is 25 to 30 min. The pressure applied during the pressing process is 1 to 1.6 kg / cm 2 .
9. The method for preparing cheese stored at room temperature according to claim 4, characterized in that: In step six, the temperature in the drying oven during the constant temperature drying process is 30-40° C., and the constant temperature drying time is 760-1500 min.
10. The method for preparing cheese stored at room temperature according to claim 4, characterized in that: In the step seven, during the bag sterilization process, an electron beam with a dose of 10 to 20 kGy is used for continuous radiation for 30 to 40 minutes, and the heat treatment requires the packaged cheese to be placed at a temperature of 60 to 65° C. for continuous standing for 30 to 35 minutes.