CN114557383B - Milk sterilization method with low protein denaturation rate - Google Patents
Milk sterilization method with low protein denaturation rate Download PDFInfo
- Publication number
- CN114557383B CN114557383B CN202111453369.4A CN202111453369A CN114557383B CN 114557383 B CN114557383 B CN 114557383B CN 202111453369 A CN202111453369 A CN 202111453369A CN 114557383 B CN114557383 B CN 114557383B
- Authority
- CN
- China
- Prior art keywords
- milk
- sterilization
- index
- sterilizing
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 235000013336 milk Nutrition 0.000 title claims abstract description 146
- 239000008267 milk Substances 0.000 title claims abstract description 146
- 210000004080 milk Anatomy 0.000 title claims abstract description 146
- 230000001954 sterilising effect Effects 0.000 title claims abstract description 116
- 238000004659 sterilization and disinfection Methods 0.000 title claims abstract description 103
- 238000000034 method Methods 0.000 title claims abstract description 40
- 102000004169 proteins and genes Human genes 0.000 title claims abstract description 29
- 108090000623 proteins and genes Proteins 0.000 title claims abstract description 29
- 238000004925 denaturation Methods 0.000 title claims abstract description 23
- 230000036425 denaturation Effects 0.000 title claims abstract description 23
- 238000001816 cooling Methods 0.000 claims abstract description 18
- 235000020191 long-life milk Nutrition 0.000 claims abstract description 17
- 238000001704 evaporation Methods 0.000 claims abstract description 9
- 238000001514 detection method Methods 0.000 claims abstract description 8
- 229920001184 polypeptide Polymers 0.000 claims description 20
- 102000004196 processed proteins & peptides Human genes 0.000 claims description 20
- 108090000765 processed proteins & peptides Proteins 0.000 claims description 20
- 235000020185 raw untreated milk Nutrition 0.000 claims description 14
- 230000007704 transition Effects 0.000 claims description 11
- 235000013861 fat-free Nutrition 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 6
- 108091081062 Repeated sequence (DNA) Proteins 0.000 claims description 5
- 239000012141 concentrate Substances 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 claims 1
- 238000012216 screening Methods 0.000 claims 1
- 238000009928 pasteurization Methods 0.000 abstract description 18
- 230000000694 effects Effects 0.000 abstract description 10
- 239000002253 acid Substances 0.000 abstract description 4
- 235000013365 dairy product Nutrition 0.000 abstract description 2
- 235000018102 proteins Nutrition 0.000 description 25
- 230000008569 process Effects 0.000 description 15
- 102000014171 Milk Proteins Human genes 0.000 description 9
- 108010011756 Milk Proteins Proteins 0.000 description 9
- 150000001413 amino acids Chemical class 0.000 description 9
- 235000021239 milk protein Nutrition 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 238000001914 filtration Methods 0.000 description 8
- 238000000746 purification Methods 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000005086 pumping Methods 0.000 description 6
- 102000010445 Lactoferrin Human genes 0.000 description 5
- 108010063045 Lactoferrin Proteins 0.000 description 5
- CSSYQJWUGATIHM-IKGCZBKSSA-N l-phenylalanyl-l-lysyl-l-cysteinyl-l-arginyl-l-arginyl-l-tryptophyl-l-glutaminyl-l-tryptophyl-l-arginyl-l-methionyl-l-lysyl-l-lysyl-l-leucylglycyl-l-alanyl-l-prolyl-l-seryl-l-isoleucyl-l-threonyl-l-cysteinyl-l-valyl-l-arginyl-l-arginyl-l-alanyl-l-phenylal Chemical compound C([C@H](N)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CS)C(=O)N[C@@H](CCCNC(N)=N)C(=O)N[C@@H](CCCNC(N)=N)C(=O)N[C@@H](CC=1C2=CC=CC=C2NC=1)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@@H](CC=1C2=CC=CC=C2NC=1)C(=O)N[C@@H](CCCNC(N)=N)C(=O)N[C@@H](CCSC)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N[C@@H](C)C(=O)N1CCC[C@H]1C(=O)N[C@@H](CO)C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CS)C(=O)N[C@@H](C(C)C)C(=O)N[C@@H](CCCNC(N)=N)C(=O)N[C@@H](CCCNC(N)=N)C(=O)N[C@@H](C)C(=O)N[C@@H](CC=1C=CC=CC=1)C(O)=O)C1=CC=CC=C1 CSSYQJWUGATIHM-IKGCZBKSSA-N 0.000 description 5
- 235000021242 lactoferrin Nutrition 0.000 description 5
- 229940078795 lactoferrin Drugs 0.000 description 5
- 239000011552 falling film Substances 0.000 description 4
- 238000011049 filling Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 230000002209 hydrophobic effect Effects 0.000 description 4
- 239000005457 ice water Substances 0.000 description 4
- 235000015097 nutrients Nutrition 0.000 description 4
- 238000007789 sealing Methods 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- 108060003951 Immunoglobulin Proteins 0.000 description 3
- GUBGYTABKSRVRQ-QKKXKWKRSA-N Lactose Natural products OC[C@H]1O[C@@H](O[C@H]2[C@H](O)[C@@H](O)C(O)O[C@@H]2CO)[C@H](O)[C@@H](O)[C@H]1O GUBGYTABKSRVRQ-QKKXKWKRSA-N 0.000 description 3
- 239000004472 Lysine Substances 0.000 description 3
- KDXKERNSBIXSRK-UHFFFAOYSA-N Lysine Natural products NCCCCC(N)C(O)=O KDXKERNSBIXSRK-UHFFFAOYSA-N 0.000 description 3
- 230000003115 biocidal effect Effects 0.000 description 3
- 238000000265 homogenisation Methods 0.000 description 3
- 235000020603 homogenised milk Nutrition 0.000 description 3
- 102000018358 immunoglobulin Human genes 0.000 description 3
- 239000008101 lactose Substances 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 238000005057 refrigeration Methods 0.000 description 3
- 230000001953 sensory effect Effects 0.000 description 3
- 210000001082 somatic cell Anatomy 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 102000004961 Furin Human genes 0.000 description 2
- 108090001126 Furin Proteins 0.000 description 2
- 244000052616 bacterial pathogen Species 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 244000005700 microbiome Species 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000004475 Arginine Substances 0.000 description 1
- 102000003992 Peroxidases Human genes 0.000 description 1
- ODKSFYDXXFIFQN-UHFFFAOYSA-N arginine Natural products OC(=O)C(N)CCCNC(N)=N ODKSFYDXXFIFQN-UHFFFAOYSA-N 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 235000013405 beer Nutrition 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 235000020247 cow milk Nutrition 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 238000010353 genetic engineering Methods 0.000 description 1
- 238000001727 in vivo Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 235000020200 pasteurised milk Nutrition 0.000 description 1
- 108040007629 peroxidase activity proteins Proteins 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000003206 sterilizing agent Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
- A23C3/00—Preservation of milk or milk preparations
- A23C3/02—Preservation of milk or milk preparations by heating
- A23C3/03—Preservation of milk or milk preparations by heating the materials being loose unpacked
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
- A23C9/00—Milk preparations; Milk powder or milk powder preparations
- A23C9/152—Milk preparations; Milk powder or milk powder preparations containing additives
- A23C9/1526—Amino acids; Peptides; Protein hydrolysates; Nucleic acids; Derivatives thereof
Abstract
The invention relates to the technical field of dairy processing, and discloses a milk sterilization method with low protein denaturation rate, which comprises the following steps: pre-sterilizing the milk at 62-68 ℃ for 15-20 s; detecting the pre-sterilized milk, and if the detection result does not reach the index, normalizing until the index is reached; preheating milk reaching the index to 60-65 ℃; flash-evaporating and sterilizing the preheated milk, controlling the temperature of an inlet heat source to be 70-85 ℃, the vacuum degree to be-0.6-0.8 MPa, and the center temperature of the milk to be not more than 65 ℃ and the flash-evaporating and sterilizing time to be 10-15 s; cooling the milk after the secondary sterilization. The invention performs pre-sterilization and standardization before secondary sterilization, combines flash sterilization with pasteurization during secondary sterilization, can ensure sterilization effect, simultaneously reduce protein denaturation and furoic acid generation during sterilization, and improve milk quality.
Description
Technical Field
The invention relates to the technical field of dairy processing, in particular to a milk sterilization method with low protein denaturation rate.
Background
Pasteurization, also called pasteurization, is a low temperature sterilization method invented by microbiologists Pasteur, and can better keep nutrients in food from being destroyed while killing germs due to the relatively low sterilization temperature. The classical pasteurization process is carried out for 30min at 60-65 ℃, and is widely used in industries such as beer and the like; another pasteurization method is to keep the temperature between 85 and 90 ℃ for 15 to 16 seconds, and is widely used in the food industry.
In the existing pasteurized fresh milk production process, the pasteurization mode is generally selected to be kept at 80-85 ℃ for 15-25 s, belonging to the pasteurization at higher temperature. The selected sterilization temperature is higher and the time is longer, so that the sterilization efficiency can be better ensured, the sterilization rate of the pasteurized fresh milk is 100 percent qualified, but simultaneously, the higher sterilization temperature is easy to destroy nutrient substances in the milk, the nutrient components such as peroxidase, lactoferrin and the like in the milk are directly lost, and in addition, the Maillard reaction of lysine and lactose in protein can be caused to generate furfuryl amino acid. Taking lactoferrin as an example, the UHT sterilizing agent almost completely loses, the pasteurization loss rate at 85 ℃ is over ninety percent, and the pasteurization loss rate at 79 ℃ is reduced to about eighty percent. Therefore, how to accurately adjust and control the pasteurization temperature and the pasteurization time is of great importance for improving the pasteurized milk quality.
In the prior art, a manner of precisely controlling the heating time or temperature is often adopted to reduce the influence of sterilization on the milk quality (nutrient substances, bran amino acid content and the like) and ensure the sterilization effect, for example, the patent with the application number of CN201710382008.2 improves the sterilization effect by precisely controlling the pasteurization holding time, thereby providing a part of a reliable quality preparation assurance system for high-quality milk. However, such a method for controlling the heating condition singly has limitations, is difficult to solve the contradiction between the sterilizing effect and the milk quality, and has limited effects in improving the sterilizing effect and the milk quality.
Disclosure of Invention
In order to solve the technical problems, the invention provides a milk sterilization method with low protein denaturation rate. The invention performs pre-sterilization and standardization before secondary sterilization, combines flash sterilization with pasteurization during secondary sterilization, can ensure sterilization effect, simultaneously reduce protein denaturation and furoic acid generation during sterilization, and improve milk quality.
The specific technical scheme of the invention is as follows:
a milk sterilization method with low protein denaturation rate comprises the following steps:
(1) Pre-sterilization: pre-sterilizing milk at 62-68 ℃ for 15-20 s;
(2) Standardization: detecting the pre-sterilized milk, and if the detection result does not reach the index, normalizing until the index is reached;
(3) Preheating: preheating the milk reaching the index to 60-65 ℃;
(4) And (3) secondary sterilization: flash-evaporating and sterilizing the preheated milk, controlling the temperature of an inlet heat source to be 70-85 ℃, the vacuum degree to be-0.6-0.8 MPa, and the center temperature of the milk to be not more than 65 ℃ and the flash-evaporating and sterilizing time to be 10-15 s;
(5) And (3) cooling: cooling the milk after the secondary sterilization.
In the step (1), most microorganisms and pathogenic bacteria which are easy to reproduce can be killed by pre-sterilization, so that a foundation is laid for reducing the sterilization strength in the subsequent secondary sterilization process; after pre-sterilization, the milk is standardized, so that the influence of the pre-sterilization on the milk quality can be made up to a certain extent.
Based on the pre-sterilization, the milk is subjected to secondary sterilization in the step (4), so that microorganisms in the milk can be further reduced. In addition, flash sterilization and pasteurization are combined during secondary sterilization, the boiling temperature of milk can be controlled between 40 ℃ and 60 ℃ by controlling the vacuum degree, so that the milk temperature is prevented from being too high, and the milk is in a film state in the evaporator, so that the evaporation speed is high, the heating time is short, the discharging temperature can be reduced rapidly, and in this way, the sterilization effect is ensured, and simultaneously, the denaturation of protein and the generation of furfuryl amino acid in the sterilization process are reduced, and the milk quality is improved. In addition, various continuous multi-effect evaporators, in particular falling film type or plate type evaporators, can be adopted for flash sterilization, and the main characteristic of the evaporators is that cow milk is continuously evaporated through a heater in a single way, so that the evaporator is suitable for large-scale continuous production and is favorable for improving labor production efficiency, ensuring product quality and reducing energy consumption.
Preferably, in the step (2), the index is: the fat content in milk is not less than 3.3wt%, the protein content is not less than 2.95wt%, and the solid content of non-fat milk is not less than 8.2wt%; the standardized method is to concentrate the milk until the milk reaches the index.
Preferably, before step (1), the raw milk is filtered through a 80-100 mesh sieve, and then purified.
Preferably, the total number of colonies in the raw milk is not more than 1X 10 5 CFU/mL.
Preferably, before step (1), an elastin-like polypeptide is added to the milk; the phase transition temperature of the elastin-like polypeptide is 40-55 ℃.
Elastin-like polypeptides (ELPs) are temperature-sensitive polymers, and after the elastin-like polypeptides are added into milk, the influence of sterilization on the quality of the milk can be reduced, and the specific mechanism is as follows: before sterilization, the temperature of the milk is lower than the phase transition temperature of ELPs, the ELPs are dissolved in the milk, and the polymer chains are in a stretched state; in the sterilization process, when the temperature rises to be higher than the phase transition temperature of the ELPs, the ELPs start to gather and are coated on the surfaces of hydrophobic proteins such as lactoferrin, immunoglobulin and the like through hydrophobic interaction, so that the protective effect can be exerted in the sterilization process, the thermal denaturation of the proteins in milk is reduced, and the reaction of lysine in the milk proteins and lactose is reduced to generate furin; in the cooling process after sterilization, the ELPs are redissolved and the protein in the ELPs is released along with the reduction of the temperature, so that the ELPs are prevented from coating the protein to cause milk turbidity.
In addition, the ELPs have better biocompatibility, can be naturally degraded into amino acids in vivo, are nontoxic to human bodies, and can supplement amino acids for the human bodies.
Further, the elastin-like polypeptide is composed of VGVPG VGVPG GGVPG AGVPG VGVPG repeat units, the number of repetitions being 30.
Through genetic engineering, elastin-like polypeptides of various sequences can be produced in high throughput, and ELPs with required phase transition temperature can be obtained by designing the sequences of the ELPs. For ELPs composed of 30 VGVPG VGVPG GGVPG AGVPG VGVPG repeated sequence units, the phase transition temperature is about 41 ℃, the ELPs can be coated on the surface of milk protein in the pre-sterilization and secondary sterilization processes, the protection effect is achieved, and when the milk is stored and drunk at room temperature, the ELPs are not aggregated to cause turbidity in the milk.
Further, the addition amount of the elastin-like polypeptide in milk is 0.2-0.8 mg/mL.
Preferably, in step (3), after preheating, the milk is homogenized.
Preferably, in the step (5), the milk after the secondary sterilization is cooled to 2-6 ℃.
Compared with the prior art, the invention has the following advantages:
(1) The method has the advantages that pre-sterilization and standardization are carried out before secondary sterilization, flash sterilization and pasteurization are combined during secondary sterilization, so that the sterilization effect is ensured, the denaturation of protein and the production of furoic acid in the sterilization process are reduced, and the milk quality is improved;
(2) By adding the elastin-like polypeptide into milk, the protein can be protected, and the denaturation of the protein and the production of furoic acid in the sterilization process can be reduced.
Detailed Description
The invention is further described below with reference to examples.
General examples
A milk sterilization method with low protein denaturation rate comprises the following steps:
(1) And (5) acceptance checking: detecting raw milk (raw fresh milk) to ensure that the total colony count is less than or equal to 1 multiplied by 10 5 CFU/mL;
(2) And (3) filtering: filtering the qualified milk by a 80-100 mesh sieve;
(3) Purifying milk: purifying the filtered milk at a speed of 5t/h by adopting disc type equipment, and then refrigerating at a temperature of 2-6 ℃;
(4) Pre-sterilization: pre-sterilizing the milk after purifying the milk at 62-68 ℃ for 15-20 s;
(5) Standardization: detecting whether the pre-sterilized milk meets the following indexes: the fat content is not less than 3.3wt%, the protein content is not less than 2.95wt%, and the non-fat milk solid content is not less than 8.2wt%; if the detection result does not reach the index, concentrating the milk until the index is reached;
(6) Preheating: preheating the milk reaching the index to 60-65 ℃;
(7) Homogenizing: homogenizing the preheated milk;
(8) And (3) secondary sterilization: flash-evaporating and sterilizing the preheated milk, controlling the temperature of an inlet heat source to be 70-85 ℃, the vacuum degree to be-0.6-0.8 MPa, and the center temperature of the milk to be not more than 65 ℃ and the flash-evaporating and sterilizing time to be 10-15 s;
(9) And (3) cooling: cooling the milk after secondary sterilization to 2-6 ℃ by ice water, and then filling and sealing to obtain the sterilizing milk.
Optionally, in the step (4), before pre-sterilization, adding the elastin-like polypeptide into the milk after milk purification in an amount of 0.2-0.8 mg/mL; the phase transition temperature of the elastin-like polypeptide is 40-55 ℃.
Example 1
A milk sterilization method with low protein denaturation rate comprises the following steps:
(1) And (5) acceptance checking: detecting raw milk (raw fresh milk), ensuring that the total colony count is less than or equal to 1 multiplied by 10 5 CFU/mL, the somatic cells are less than or equal to 4 multiplied by 10 5/mL, the sensory index is qualified, the test of 75% neutral alcohol (20 ℃) and milk is negative in 1:1, the physicochemical index is qualified, and the antibiotic residue is negative;
(2) And (3) filtering: filtering qualified milk by a triple filter with 100 meshes;
(3) Purifying milk: purifying the filtered milk at a speed of 5t/h by adopting disc type equipment, and then pumping the milk into a storage tank with a temperature of 2 ℃ for refrigeration;
(4) Pre-sterilization: pre-sterilizing the milk after milk purification at 62 ℃ for 15s;
(5) Standardization: detecting whether the pre-sterilized milk meets the following indexes: the fat content is not less than 3.3wt%, the protein content is not less than 2.95wt%, and the non-fat milk solid content is not less than 8.2wt%; if the detection result does not reach the index, concentrating the milk by a single-effect falling film evaporator until the index is reached;
(6) Preheating: preheating milk reaching the index to 60 ℃ by adopting a plate heat exchanger;
(7) Homogenizing: carrying out secondary homogenization on the preheated milk, wherein the primary pressure is 16MPa, and the secondary pressure is 4MPa;
(8) And (3) secondary sterilization: pumping the homogenized milk into a flash tank, controlling the temperature of an inlet heat source to be 70 ℃, controlling the vacuum degree to be-0.6 MPa, controlling the temperature of the center of milk not to exceed 65 ℃, and performing flash sterilization for 15s;
(9) And (3) cooling: and cooling the milk subjected to secondary sterilization to 2 ℃ by using ice water, and then filling and sealing to obtain the sterilized milk.
Example 2
A milk sterilization method with low protein denaturation rate comprises the following steps:
(1) And (5) acceptance checking: detecting raw milk (raw fresh milk), ensuring that the total colony count is less than or equal to 1 multiplied by 10 5 CFU/mL, the somatic cells are less than or equal to 3 multiplied by 10 5/mL, the sensory index is qualified, the test of 75% neutral alcohol (20 ℃) and milk is negative in 1:1, the physicochemical index is qualified, and the antibiotic residue is negative;
(2) And (3) filtering: filtering qualified milk by a triple filter with 100 meshes;
(3) Purifying milk: purifying the filtered milk at a speed of 5t/h by adopting disc type equipment, and then pumping the milk into a storage tank with a temperature of 4 ℃ for refrigeration;
(4) Pre-sterilization: pre-sterilizing the milk after milk purification at 65 ℃ for 18s;
(5) Standardization: detecting whether the pre-sterilized milk meets the following indexes: the fat content is not less than 3.3wt%, the protein content is not less than 2.95wt%, and the non-fat milk solid content is not less than 8.2wt%; if the detection result does not reach the index, concentrating the milk by a single-effect falling film evaporator until the index is reached;
(6) Preheating: preheating milk reaching the index to 62 ℃ by adopting a plate heat exchanger;
(7) Homogenizing: carrying out secondary homogenization on the preheated milk, wherein the primary pressure is 17MPa, and the secondary pressure is 5MPa;
(8) And (3) secondary sterilization: pumping the homogenized milk into a flash tank, controlling the temperature of an inlet heat source to be 75 ℃, the vacuum degree to be 0.5MPa, and flash sterilizing the milk for 12s at the center temperature of the milk not more than 65 ℃;
(9) And (3) cooling: and cooling the milk subjected to secondary sterilization to 4 ℃ by using ice water, and then filling and sealing to obtain the sterilized milk.
Example 3
A milk sterilization method with low protein denaturation rate comprises the following steps:
(1) And (5) acceptance checking: detecting raw milk (raw fresh milk), ensuring that the total colony count is less than or equal to 1 multiplied by 10 5 CFU/mL, the somatic cells are less than or equal to 3 multiplied by 10 5/mL, the sensory index is qualified, the test of 75% neutral alcohol (20 ℃) and milk is negative in 1:1, the physicochemical index is qualified, and the antibiotic residue is negative;
(2) And (3) filtering: filtering qualified milk by a triple filter with 100 meshes;
(3) Purifying milk: purifying the filtered milk at a speed of 5t/h by adopting disc type equipment, and then pumping the milk into a storage tank with a temperature of 6 ℃ for refrigeration;
(4) Pre-sterilization: pre-sterilizing the milk after milk purification at 68 ℃ for 20s;
(5) Standardization: detecting whether the pre-sterilized milk meets the following indexes: the fat content is not less than 3.3wt%, the protein content is not less than 2.95wt%, and the non-fat milk solid content is not less than 8.2wt%; if the detection result does not reach the index, concentrating the milk by a single-effect falling film evaporator until the index is reached;
(6) Preheating: preheating milk reaching the index to 65 ℃ by adopting a plate heat exchanger;
(7) Homogenizing: carrying out secondary homogenization on the preheated milk, wherein the primary pressure is 18MPa, and the secondary pressure is 6MPa;
(8) And (3) secondary sterilization: pumping the homogenized milk into a flash tank, controlling the temperature of an inlet heat source to be 85 ℃, controlling the vacuum degree to be 0.8MPa, controlling the temperature of the center of milk to be not more than 65 ℃, and performing flash sterilization for 10s;
(9) And (3) cooling: and cooling the milk subjected to secondary sterilization to 6 ℃ by using ice water, and then filling and sealing to obtain the sterilized milk.
Example 4
The raw milk used in this example was the same as in example 1, except that in step (4), elastin-like polypeptide was added to the milk after milk purification in an amount of 0.2mg/mL before pre-sterilization; the elastin-like polypeptide is composed of VGVPG VGVPG GGVPG AGVPG VGVPG repeated sequence units, the repeated times are 30 times, and the phase transition temperature is 41 ℃.
In this example, turbidity was observed in the milk after preheating; during the cooling process, the milk regains clarity.
Example 5
The raw milk used in this example was the same as in example 1, except that in step (4), elastin-like polypeptide was added to the milk after milk purification in an amount of 0.5mg/mL before pre-sterilization; the elastin-like polypeptide is composed of VGVPG VGVPG GGVPG AGVPG VGVPG repeated sequence units, the repeated times are 30 times, and the phase transition temperature is 41 ℃.
In this example, turbidity was observed in the milk after preheating; during the cooling process, the milk regains clarity.
Example 6
The raw milk used in this example was the same as in example 1, except that in step (4), elastin-like polypeptide was added to the milk after milk purification in an amount of 0.8mg/mL before pre-sterilization; the elastin-like polypeptide is composed of VGVPG VGVPG GGVPG AGVPG VGVPG repeated sequence units, the repeated times are 30 times, and the phase transition temperature is 41 ℃.
In this example, turbidity was observed in the milk after preheating; during the cooling process, the milk regains clarity.
Comparative example 1
The raw milk used in this comparative example was the same as in example 1, except that step (4) was not performed.
Comparative example 2
The raw milk used in this comparative example was the same as in example 1, except that in step (8), pasteurization, i.e., sterilization at 70℃for 10 seconds, was performed.
Test case
In examples 1 to 6 and comparative examples 1 to 2, the content of each milk protein (. Beta. -lactoglobulin, immunoglobulin and lactoferrin) in raw milk, and the arginine content in sterilized milk, the content of each milk protein and the total number of colonies were examined, and each group was repeatedly tested 5 times, outliers were discarded, an average value was taken, and the denaturation rate and sterilization rate of each milk protein were calculated. The detection results are shown in Table 1.
TABLE 1
As can be seen from table 1:
(1) Compared with comparative example 1, the bacterial colony number in the sterilized milk obtained in example 1 is obviously smaller, and the content of each milk protein in the sterilized milk is smaller than that in comparative example 1, which indicates that the milk is pre-sterilized before secondary sterilization, so that the sterilization effect can be effectively improved, and the influence on the protein is smaller.
(2) The significantly lower number of colonies in the sterilized milk obtained in example 1 compared to comparative example 2, and significantly lower denaturation rate of each milk protein and bran amino acid content in the sterilized milk, indicate that the combination of pasteurization and flash sterilization can effectively improve the sterilization effect and reduce the denaturation of protein and the production of bran amino acids compared to conventional pasteurization.
(3) Compared with example 1, the denaturation rate of each milk protein and the content of furfuryl amino acid in the sterilized milk in examples 4 to 6 are obviously lower, which shows that the denaturation of the protein and the production of furfuryl amino acid in the sterilization process can be reduced by adding the elastin-like polypeptide into the milk before sterilization; in addition, no significant turbidity was observed in the sterilized milk obtained in examples 4 to 6, indicating that addition of ELPs did not cause milk turbidity. The reason is that: in the sterilization process, when the temperature rises to be higher than the phase transition temperature of the ELPs, the ELPs start to gather and are coated on the surfaces of hydrophobic proteins such as lactoferrin, immunoglobulin and the like through hydrophobic interaction, so that the protective effect can be exerted in the pre-sterilization, the pre-heating and the secondary sterilization, the thermal denaturation of proteins in milk is reduced, and the reaction of lysine in milk proteins and lactose is reduced to generate furin; in the cooling process after sterilization, the ELPs are redissolved and the protein in the ELPs is released along with the reduction of the temperature, so that the ELPs are prevented from coating the protein to cause milk turbidity.
The raw materials and equipment used in the invention are common raw materials and equipment in the field unless specified otherwise; the methods used in the present invention are conventional in the art unless otherwise specified.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any simple modification, variation and equivalent transformation of the above embodiment according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.
Claims (8)
1. The milk sterilization method with low protein denaturation rate is characterized by comprising the following steps:
(1) Pre-sterilization: adding elastin-like polypeptide with the phase transition temperature of 40-55 ℃ into milk, and pre-sterilizing for 15-20 s at 62-68 ℃; the elastin-like polypeptide consists of VGVPG VGVPG GGVPG AGVPG VGVPG repeated sequence units, and the repeated times are 30 times; the addition amount of the elastin-like polypeptide in milk is 0.2-0.8 mg/mL;
(2) Standardization: detecting the pre-sterilized milk, and if the detection result does not reach the index, normalizing until the index is reached;
(3) Preheating: preheating milk reaching the index to 60-65 ℃;
(4) And (3) secondary sterilization: flash-evaporating and sterilizing the preheated milk, controlling the temperature of an inlet heat source to be 70-85 ℃, the vacuum degree to be-0.6-0.8 MPa, and the center temperature of the milk to be not more than 65 ℃ and the flash-evaporating and sterilizing time to be 10-15 s;
(5) And (3) cooling: cooling the milk after the secondary sterilization.
2. The sterilization method according to claim 1, wherein in the step (2), the index is: the milk has fat content not less than 3.3wt%, protein content not less than 2.95wt%, and non-fat milk solid content not less than 8.2wt%.
3. The sterilization method according to claim 1, wherein in the step (2), the standardized method is to concentrate milk until the milk reaches an index.
4. The sterilization method according to claim 1, wherein the raw milk is subjected to 80-100 mesh screening before the step (1), and then is subjected to milk cleaning.
5. The method according to claim 4, wherein the total number of colonies in the raw milk is not more than 1X 10 5 CFU/mL.
6. The sterilization method according to claim 1, wherein in the step (3), the preheating is performed using a plate heat exchanger.
7. The sterilization method according to claim 1, wherein in the step (3), after preheating, the milk is homogenized.
8. The sterilization method according to claim 1, wherein in the step (5), the milk after the secondary sterilization is cooled to 2-6 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111453369.4A CN114557383B (en) | 2021-12-01 | 2021-12-01 | Milk sterilization method with low protein denaturation rate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111453369.4A CN114557383B (en) | 2021-12-01 | 2021-12-01 | Milk sterilization method with low protein denaturation rate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114557383A CN114557383A (en) | 2022-05-31 |
| CN114557383B true CN114557383B (en) | 2024-04-16 |
Family
ID=81711813
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111453369.4A Active CN114557383B (en) | 2021-12-01 | 2021-12-01 | Milk sterilization method with low protein denaturation rate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114557383B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114982827A (en) * | 2022-05-07 | 2022-09-02 | 浙江美丽健乳业有限公司 | Sterilizing and fresh-keeping method for raw milk |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101151978A (en) * | 2006-09-26 | 2008-04-02 | 西北农林科技大学 | Liquid goat's milk capable of long-term storing in normal temperature condition and method for preparing the same |
| CN101955960A (en) * | 2010-08-03 | 2011-01-26 | 中山大学 | Method for purifying recombinant lactase by using elastin like protein tag |
| UA67788U (en) * | 2011-07-04 | 2012-03-12 | Украинская Инженерно-Педагогическая Академия | Method for making milk dessert with elamin |
| CN104558120A (en) * | 2014-12-25 | 2015-04-29 | 南京市妇幼保健院 | Immunoregulatory polypeptide as well as preparation method and application thereof |
| CN105325553A (en) * | 2014-06-05 | 2016-02-17 | 内蒙古蒙牛乳业（集团）股份有限公司 | Zero-addition high-calcium milk and preparation method thereof |
| CN106857817A (en) * | 2017-04-17 | 2017-06-20 | 安徽华园乳业有限责任公司 | A kind of production method of pasture raw milk |
| CN108935665A (en) * | 2018-07-26 | 2018-12-07 | 内蒙古蒙牛乳业（集团）股份有限公司 | milk and preparation method thereof |
| CN113207959A (en) * | 2020-01-21 | 2021-08-06 | 内蒙古伊利实业集团股份有限公司 | Method for regulating and controlling flavor of sterilized milk, sterilized milk with pasteurized milk flavor and preparation method thereof |
-
2021
- 2021-12-01 CN CN202111453369.4A patent/CN114557383B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101151978A (en) * | 2006-09-26 | 2008-04-02 | 西北农林科技大学 | Liquid goat's milk capable of long-term storing in normal temperature condition and method for preparing the same |
| CN101955960A (en) * | 2010-08-03 | 2011-01-26 | 中山大学 | Method for purifying recombinant lactase by using elastin like protein tag |
| UA67788U (en) * | 2011-07-04 | 2012-03-12 | Украинская Инженерно-Педагогическая Академия | Method for making milk dessert with elamin |
| CN105325553A (en) * | 2014-06-05 | 2016-02-17 | 内蒙古蒙牛乳业（集团）股份有限公司 | Zero-addition high-calcium milk and preparation method thereof |
| CN104558120A (en) * | 2014-12-25 | 2015-04-29 | 南京市妇幼保健院 | Immunoregulatory polypeptide as well as preparation method and application thereof |
| CN106857817A (en) * | 2017-04-17 | 2017-06-20 | 安徽华园乳业有限责任公司 | A kind of production method of pasture raw milk |
| CN108935665A (en) * | 2018-07-26 | 2018-12-07 | 内蒙古蒙牛乳业（集团）股份有限公司 | milk and preparation method thereof |
| CN113207959A (en) * | 2020-01-21 | 2021-08-06 | 内蒙古伊利实业集团股份有限公司 | Method for regulating and controlling flavor of sterilized milk, sterilized milk with pasteurized milk flavor and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114557383A (en) | 2022-05-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0617897B1 (en) | Method and arrangement for continuous sterilization of a liquid milk based product | |
| JP4567737B2 (en) | Acid milk product manufacturing method, milk processing method therefor, acid milk manufacturing line, and milk processing apparatus in the line | |
| CA2622691C (en) | Method for improving texture of fermented milk | |
| CN111194824B (en) | Concentrated milk protein liquid and preparation method thereof | |
| CN113826695B (en) | Milk product and preparation method thereof, dairy product and preparation method thereof | |
| CN114557383B (en) | Milk sterilization method with low protein denaturation rate | |
| CN101356938A (en) | Production technique of pasteurize milk | |
| CN113973918A (en) | High-calcium fresh milk and preparation method thereof | |
| CN108651621A (en) | A kind of production method of membrane filtration concentration acidified milk | |
| CN112868762A (en) | Low-temperature pasteurized milk and preparation method thereof | |
| CN109042874A (en) | A kind of preparation method of sterilization cream | |
| CA2067629C (en) | Process for the production of an evaporated milk product | |
| CN112841302A (en) | Normal-temperature milk with long shelf life and preparation method thereof | |
| CN114009497A (en) | Method for processing concentrated milk | |
| JP3062095B2 (en) | Powdered milk and method for producing the same | |
| CN113854356A (en) | Active substance-rich fresh milk with long shelf life and preparation method thereof | |
| CN113854355A (en) | Liquid milk suitable for storage at room temperature and rich in active substances and preparation method thereof | |
| CN112868774B (en) | Production method for improving viscosity of normal-temperature fermented milk | |
| CN113632839A (en) | Pasteurized milk containing probiotics and preparation method thereof | |
| CN112219897A (en) | Method for producing low-temperature sterilized fresh milk | |
| CN116941671B (en) | High-protein normal-temperature yoghourt and preparation method thereof | |
| CN113693130A (en) | Normal temperature active milk and preparation method thereof | |
| CN116019144A (en) | Yoghurt and preparation method thereof | |
| CN114946945A (en) | Yoghourt and preparation method thereof | |
| CN115989829A (en) | Milk and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant |