CN116019146A - Strong-flavor milk and preparation method thereof - Google Patents

Abstract

The invention provides a strong-flavor milk and a preparation method thereof. The preparation method comprises the following steps: (1) fat separation: fat separation is carried out on raw milk to obtain cream and skimmed milk; (2) ultrafiltration: performing ultrafiltration operation on the skimmed milk to obtain ultrafiltration trapped fluid and ultrafiltration permeate; (3) reverse osmosis (nanofiltration process may also be used): performing reverse osmosis operation on the ultrafiltration permeate to obtain reverse osmosis trapped fluid and reverse osmosis permeate; (4) component recombination: and mixing the ultrafiltration trapped fluid, the reverse osmosis permeate and the cream. The preparation method can be suitable for the production of various products (products with different protein contents, different fat contents and different lactose contents can be produced): such as: the concentrated milk with high protein content and low protein content can be produced, and additives and anhydrous cream are not added, so that the effects of not inputting the quality of the product with the taste and the shelf life to the added additives can be achieved.

Description

Strong-flavor milk and preparation method thereof

Technical Field

The invention belongs to the technical field of milk processing, and particularly relates to aroma type milk and a preparation method thereof.

Background

Since the market of concentrated milk, the concentrated milk is mainly sold in a fragrant way, and the concentrated milk is uniformly accepted and well-appreciated by consumers. Many concentrated milk products are also on the market, but from the ingredient list, all the products are added with food additives, and only the prepared milk products can be taken away. And the production process adopts the following production process: raw milk inspection, milk collection, filtration, cooling, storage, standardization, pasteurization, cooling, storage, material conversion, ultrahigh temperature sterilization, cooling, filling, boxing, spot check and delivery. The standardized operation in the production process adopts a flash evaporation process, so that the heating intensity of milk is high, the consumption of steam is high, the adjustment range of indexes is limited, and meanwhile, the occupied area of flash evaporation equipment is large and the transportation cost is high; the primary pressure of the primary homogenization during the ultra-high temperature sterilization is only 250bar, and the secondary pressure is only 50bar. The produced concentrated milk is reviewed by some consumers on the web: the concentrated milk has additives and anhydrous cream, is prepared milk, and is not as nutritious as pure milk, and children cannot drink negative comments.

Therefore, the development of the concentrated milk product with clean labels (raw milk only in a batching table) is urgently needed, and the additive and the anhydrous cream are removed, so that the taste of the product can be ensured, and the normal-temperature long shelf life can be realized.

Disclosure of Invention

The invention aims to provide a preparation method of strong-flavor milk, which can achieve the effect of achieving the taste of the strong-flavor milk under the condition of not adding additives and anhydrous cream.

Another object of the present invention is to provide a highly flavored milk.

In order to achieve the above purpose, the invention provides a preparation method of aroma type milk, comprising the following steps: (1) fat separation: fat separation is carried out on raw milk to obtain cream and skimmed milk; (2) ultrafiltration: performing ultrafiltration operation on the skimmed milk to obtain ultrafiltration trapped fluid and ultrafiltration permeate; (3) reverse osmosis: performing reverse osmosis operation on the ultrafiltration permeate to obtain reverse osmosis trapped fluid and reverse osmosis permeate; (4) component recombination: and mixing the ultrafiltration trapped fluid, the reverse osmosis permeate and the cream.

According to some embodiments of the invention, between step (1) and step (2) there is also included a step of first sterilizing (preferably self-pasteurizing) the cream and the skim milk, respectively, said first sterilizing having a temperature of 72-90 ℃ for a time of 12-17s. Preferably, after sterilization, the skim milk is cooled to 1-8deg.C for storage, and the cream is cooled to 1-15deg.C for storage.

According to some embodiments of the invention, the skim milk is subjected to ultrafiltration by an ultrafiltration membrane, the skim milk entering the ultrafiltration membrane having a temperature of 1-12 ℃ and the ultrafiltration retentate and ultrafiltration permeate being stored at a temperature of 1-10 ℃.

According to some embodiments of the invention, the ultrafiltration membrane has a pore size of 5000 to 10000 daltons.

According to some embodiments of the invention, the ultrafiltration permeate is subjected to a reverse osmosis operation through a reverse osmosis membrane, the ultrafiltration permeate entering the reverse osmosis membrane at a temperature of 1-12 ℃ and the reverse osmosis retentate and the reverse osmosis permeate are stored at a temperature of 1-10 ℃.

According to some embodiments of the invention, the reverse osmosis operation can also be replaced by a nanofiltration operation, the specific operating steps being: and (3) carrying out nanofiltration operation on the ultrafiltration permeate through a nanofiltration membrane, wherein the pore size of the nanofiltration membrane is 100-300 daltons.

According to some embodiments of the present invention, it is preferable to add and stir the ultrafiltration retentate, the reverse osmosis retentate, and the reverse osmosis permeate uniformly, then add the cream, and mix uniformly to obtain the mixed feed liquid (if the cream is not uniformly mixed, the mixed feed liquid may be heated to 40-60 ℃ or other feed liquids except the cream may be heated to 40-60 ℃ before adding the cream). The mixed feed liquid obtained by the recombination of the components comprises the following components in percentage by mass: fat 3.8-6.0%, protein 2.9-6.0%, lactose 5.5-6.5%.

According to some embodiments of the invention, the homogenization and the second sterilization operation are further included sequentially after the reconstitution of the components.

According to some embodiments of the invention, the homogenized temperature is 40-80 ℃, the homogenized primary pressure is 180-400bar, and the secondary pressure is 50-100bar. Wherein, when the mass percentage of fat in the produced aroma type milk is lower than 5%, the homogenizing process step can be adopted or omitted according to practical situations, and when the mass percentage of fat is not lower than 5%, the homogenizing process step is needed.

According to some embodiments of the invention, the temperature of the second sterilization (preferably from ultra-high temperature sterilization) is 137-142 ℃ for 2-5s, the vacuum degree adopted by the second sterilization is-35 to-80 kPa, the primary homogenization pressure adopted in the second sterilization operation is 250-400bar, and the secondary homogenization pressure is 50-100bar.

According to some embodiments of the invention, the ultrafiltration retentate, reverse osmosis permeate and cream are in a mass ratio of (3-20): (1.5-25): (0-10): (0-10).

According to some specific embodiments of the invention, the raw milk comprises the following components in percentage by mass: fat 3.0-4.5%, protein 2.9-3.3%, lactose 4.0-5.0%. The mass percentage of fat in the cream is 22-42%. The weight percentage of protein in the skim milk is 2.9-3.3%, and the weight percentage of lactose is 4.0-5.0%. The protein content in the ultrafiltration trapped fluid is 2-5 times of the protein content in the skim milk, and the lactose content is the same as the lactose content in the skim milk. The lactose content in the reverse osmosis trapped fluid is 2-3 times of that in the ultrafiltration permeate fluid.

According to some embodiments of the invention, the homogenization and the second sterilization operation step are followed by a cooling and filling operation in sequence. Wherein the cooling temperature is not higher than 30 ℃, and the filling temperature is not higher than 35 ℃. Sampling after filling, detecting by a particle size analyzer, if the average particle size value of less than 90% is less than 0.80 mu m, adjusting the primary and secondary homogenizing pressures in the ultra-high temperature sterilization operation, maximally adjusting the primary homogenizing pressure to 400bar, adjusting the secondary homogenizing pressure to 100bar, and carrying out stable production after the particle size value is less than 0.80 mu m.

The invention also provides the aroma type milk prepared by the preparation method.

The preparation method of the aroma type milk provided by the invention can be suitable for the production of various products (products with different protein contents, different fat contents and different lactose contents can be produced): the method can produce the concentrated milk with high protein content and the concentrated milk with low protein content, does not add additives, can achieve the effect that the taste is not input into the concentrated milk added with the additives, can realize normal temperature long shelf life, and can ensure mellow and aromatic taste of the product while the fat does not seriously float and agglomerate in the ultra-long shelf life.

Detailed Description

In order to more clearly understand the technical features, objects and advantages of the present invention, a further detailed description will now be made of the technical scheme of the present invention. It should be understood that the following detailed description is merely exemplary, and the technical solutions of the present invention are not limited to the following detailed description.

The invention aims to provide a preparation method of concentrated-flavor milk, which can solve the problem that the concentrated-flavor milk produced by the prior art has low protein content because an additive is added in a concentrated-flavor milk batching table to ensure the taste.

Another object of the present invention is to provide a highly flavored milk.

Therefore, the invention provides a preparation method of the strong-flavor milk, which comprises the following steps:

1. fat separation: fat separation is carried out on raw milk to obtain cream and skimmed milk; wherein the raw milk comprises the following components in percentage by mass: fat 3.0-4.5% (preferably 3.5%, 3.8% and 4.0%), protein 2.9-3.3% (preferably 3.0% and 3.2%), lactose 4.0-5.0% (preferably 4.5% and 4.8%);

2. pasteurizing: the cream (fat mass% 22-42% (preferably 25%, 30%, 35% and 40%) and the skim milk (protein mass% 2.9-3.3% (preferably 3.0%, 3.2% and 3.3%), lactose mass% 4.0-5.0% (preferably 4.2%, 4.6% and 4.8%) are sterilized by 72-90 ℃ (preferably 73 ℃, 75 ℃, 80 ℃ and 85 ℃) for 12-17s (preferably 13s, 15s and 16 s), respectively, to remove microorganisms, the skim milk is cooled to 1-8 ℃ (preferably 2 ℃, 5 ℃ and 7 ℃) for storage after sterilization, and the cream is cooled to 1-15 ℃ (preferably 2 ℃, 5 ℃, 7 ℃,10 ℃ and 13 ℃) for storage.

3. Ultrafiltration: ultrafiltering the pasteurized skimmed milk with ultrafiltration membrane (aperture of 5000-10000 Dalton, preferably 6000 Dalton, 7000 Dalton, 8000 Dalton and 9000 Dalton) to obtain ultrafiltration retentate and ultrafiltration permeate; wherein the temperature of pasteurized skimmed milk entering the ultrafiltration membrane is 1-12deg.C (preferably 2deg.C, 5deg.C, 7deg.C, 9deg.C and 11deg.C), and the storage temperature of ultrafiltration retentate and ultrafiltration permeate is 1-10deg.C (preferably 2deg.C, 5deg.C, 7deg.C and 9deg.C). The protein content in the ultrafiltration trapped fluid is 2-5 times of the protein content in the skim milk, and the lactose content is the same as the lactose content in the skim milk.

4. Reverse osmosis: performing reverse osmosis operation on the ultrafiltration permeate through a reverse osmosis membrane to obtain reverse osmosis trapped fluid and reverse osmosis permeate; wherein the ultrafiltration permeate enters the reverse osmosis membrane at a temperature of 1-12deg.C (preferably 2deg.C, 5deg.C, 7deg.C, 9deg.C and 11deg.C), and the reverse osmosis retentate and the reverse osmosis permeate are stored at a temperature of 1-10deg.C (preferably 2deg.C, 5deg.C, 7deg.C and 9deg.C); the lactose content in the reverse osmosis trapped fluid is 2-3 times of that in the ultrafiltration permeate fluid; wherein the reverse osmosis operation can also be replaced by nanofiltration operation, and the specific operation steps are as follows: and (3) carrying out nanofiltration operation on the ultrafiltration permeate through a nanofiltration membrane, wherein the pore size of the nanofiltration membrane is 100-300 daltons.

5. And (3) component recombination: according to dry matter, protein and fat indexes, before homogenization, the ultrafiltration retentate, the reverse osmosis permeate and the cream are mixed according to a certain proportion (preferably mass ratio is (3-20): (1.5-25): (0-10), preferably (3-10): (1.5-5): (0-2): (0-1) and a certain sequence and uniformly stirred to obtain a mixed feed liquid (semi-finished product), preferably, the ultrafiltration retentate, the reverse osmosis retentate and the reverse osmosis permeate are added and uniformly stirred, then the cream is added and uniformly mixed (if the cream is unevenly mixed, the mixed feed liquid can be heated to 40-60 ℃ (preferably 45 ℃ and 55 ℃) or other feed liquids except the cream are heated to 40-60 ℃ (preferably 45 ℃, 50 ℃ and 55 ℃), and the mixed feed liquid obtained by recombination of the components contains the following components by mass percent (which can be adjusted to 8-6% (preferably, 4.5-6%, 6.5%, 4.5% and 3.5% of lactose, 4.5% and 4.5% (preferably, 6%), 4.5% of the concentration capacity of the finished product, 3.6% and 4.5% of the mixed feed liquid according to raw milk indexes, 3.6% (preferably, 4.5%), and 4.5% of the mixed feed liquid is preferably, 4.5% of lactose and 3.5% of the mixed feed liquid.

6. Homogenizing: homogenizing the obtained mixed solution at 40-80deg.C under primary homogenizing pressure of 180-400bar (preferably 200bar, 250bar, 300bar and 350 bar) and secondary homogenizing pressure of 50-100bar (preferably 60bar, 70bar, 80bar and 90 bar) (firstly regulating secondary homogenizing pressure gauge and then regulating primary homogenizing pressure gauge); wherein, when the mass percentage of fat in the produced aroma type milk is lower than 5%, the homogenizing process step can be adopted or omitted according to practical situations, and when the mass percentage of fat is not lower than 5%, the homogenizing process step is needed.

7. Ultrahigh temperature sterilization process

7.1 vacuum degassing: vacuum degree-35-80 kPa (preferably-40 kPa, -50kPa, -60kPa and-70 kPa).

7.2 homogenizing: the homogenization temperatures are 70-75deg.C (preferably 72deg.C, 73deg.C and 75deg.C), the primary homogenization pressures are 250-400bar (preferably 260bar, 280bar, 300bar, 350bar and 380 bar), and the secondary homogenization pressures are 50-100bar (preferably 60bar, 70bar, 80bar and 90 bar) (the secondary homogenization pressure gauge is adjusted first, and then the primary homogenization pressure gauge is adjusted).

7.3, ultra-high temperature sterilization: 137-142 ℃ (preferably 138 ℃, 140 ℃ and 141 ℃) 2-5s (preferably 4 s).

7.4 cooling: cooling the semi-finished product after the ultrahigh temperature sterilization to be less than or equal to 30 ℃.

8. And (3) filling process: the filling temperature is less than or equal to 35 ℃. Sampling after filling, detecting by a particle size analyzer, if the average particle size value of less than 90% is less than 0.80 mu m, adjusting the primary and secondary homogenizing pressures in the ultra-high temperature sterilization operation, maximally adjusting the primary homogenizing pressure to 400bar, adjusting the secondary homogenizing pressure to 100bar, and carrying out stable production after the particle size value is less than 0.80 mu m.

9. The packaging process comprises the following steps: and (5) boxing and code spraying.

The preparation method of the aroma type milk provided by the invention can be suitable for the production of various products: the high-protein clean tag concentrated milk and other products requiring the concentrated aroma can achieve the effect that the mouthfeel is not input into the additive concentrated milk.

The expression "about" in the present invention means that the specific value and reasonable extension within + -5% of the value are still included in the scope of the claimed invention. In addition, unless otherwise indicated, specific values representing amounts, volumes, or temperatures, etc. of the present invention also include reasonable extensions within the range of ±5% of the value. Such as 5% for all values in the range of (5-5 x 0.05)% - (5+5 x 0.05)%, inclusive. The expressions "normal temperature" and "room temperature" in the present invention refer to 25℃at atmospheric pressure.

Example 1

The present example provides a method for preparing a highly flavored milk ((no additives in the ingredients table, raw milk only)) comprising the following steps (the contents of fat, protein, lactose, mineral salt, dry matter in tables 1 to 15 are all in mass percent):

(1) Fat separation: fat separation is carried out on raw milk to obtain cream and skim milk, wherein the content of fat, protein and lactose in the raw milk, the cream and the skim milk are shown in tables 1-2:

TABLE 1

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Raw milk	3.8	3.2	4.8

TABLE 2

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Cream	40	0	0
2	Skim milk	0	3.3	4.6

(2) Pasteurizing: sterilizing the cream and the skim milk respectively at 85deg.C/15 s to remove microorganism, cooling the skim milk to 1-8deg.C, and storing at 1-15deg.C.

(3) Ultrafiltering the skimmed milk with ultrafiltration membrane to obtain ultrafiltration retentate and ultrafiltration permeate: (the protein content of the ultrafiltration retentate was concentrated by about 3 times, the lactose content was about equal to that of the skim milk; the protein content of the ultrafiltration permeate was about 0, the lactose content was close to that of the skim milk; the concentration times were adjusted according to the equipment capacity and the product index requirements), wherein the fat, protein and lactose contents of the ultrafiltration retentate and the ultrafiltration permeate are shown in Table 3:

TABLE 3 Table 3

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Ultrafiltration retentate	0	9.6	4.7
2	Ultrafiltering permeate	0	0	4.5

(4) Passing the ultrafiltration permeate through a reverse osmosis membrane to obtain a reverse osmosis retentate and a reverse osmosis permeate: (the content of fat and protein in the reverse osmosis trapped liquid is about 0, the content of lactose is concentrated by about 3 times, the content of fat, protein and mineral salt in the reverse osmosis liquid is about 0, and the concentration times can be adjusted according to the equipment capacity and the finished product index. Wherein the contents of fat, protein and lactose in the reverse osmosis retentate and the reverse osmosis permeate are shown in table 4:

TABLE 4 Table 4

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Reverse osmosis retentate	0	0	13
2	Reverse osmosis permeate	0	0	0

Note that: 0 represents a small amount relative to the other components, and almost no.

(5) And (3) component recombination: and mixing the cream, the ultrafiltration trapped fluid, the reverse osmosis trapped fluid and the reverse osmosis permeate fluid according to a certain proportion and a certain sequence according to the quality standard of a finished product before homogenizing according to the dry matter, protein and fat index requirements, and uniformly stirring to obtain a mixed feed liquid (semi-finished product) before homogenizing. Preferably, the ultrafiltration trapped fluid, the reverse osmosis trapped fluid and the reverse osmosis permeate are added and stirred uniformly, then the cream is added and mixed uniformly (if the cream is not uniformly mixed, the mixed feed liquid can be heated to 40-60 ℃ or other feed liquid except the cream can be heated to 40-60 ℃ before the cream is added).

The physical and chemical indexes of the semi-finished product are shown in table 5:

TABLE 5

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Strong-flavor milk semi-finished product	4.6	3.3	6.0

The proportions of the components are shown in Table 6:

TABLE 6

Sequence number	Name of the name	UF retentate	RO trapped fluid	RO permeate	Cream
						1	Strong-flavor milk semi-finished product	31.7kg	25.5kg	13.7kg	9.2kg

(6) Homogenizing: homogenizing the obtained mixed solution at 70deg.C under a primary homogenizing pressure of 250bar and a secondary homogenizing pressure of 50bar (firstly regulating a secondary homogenizing pressure gauge and then regulating a primary homogenizing pressure gauge).

(7) The ultra-high temperature sterilization process comprises the following steps:

7.1 vacuum degassing: vacuum degree-50 kpa.

7.2 homogenizing: the post-homogenization process is adopted, the homogenization temperature is 70-75 ℃, the primary homogenization pressure is 400bar, and the secondary homogenization pressure is 80bar.

7.3, ultra-high temperature sterilization: 138 ℃/4s.

7.4 cooling: cooling the semi-finished product after the ultrahigh temperature sterilization to be less than or equal to 30 ℃.

(8) And (3) filling process: the filling temperature is less than or equal to 35 ℃. Sampling after filling, detecting with particle size analyzer, and stabilizing production after 90% average particle size is below 0.80 μm.

(9) The packaging process comprises the following steps: and (5) boxing and code spraying.

Example 2

The embodiment provides a preparation method of strong-flavor milk, which comprises the following specific steps as in embodiment 1, wherein the specific steps are different from the following indexes:

the physical and chemical indexes of the semi-finished product are shown in table 7:

TABLE 7

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Strong-flavor milk semi-finished product	4.6	4.5	6.5

The composition ratios are shown in Table 8:

TABLE 8

Sequence number	Name of the name	UF retentate	RO trapped fluid	RO permeate	Cream
						1	Strong-flavor milk semi-finished product	37.5kg	26.4kg	6.8kg	9.2kg

Example 3

The embodiment provides a preparation method of strong-flavor milk, which comprises the following specific steps as in embodiment 1, wherein the specific steps are different from the following indexes:

the physical and chemical indexes of the semi-finished product are shown in table 9:

TABLE 9

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Strong-flavor milk semi-finished product	4.6	6.0	6.0

The composition ratios are shown in Table 10:

table 10

Sequence number	Name of the name	UF retentate	RO trapped fluid	RO permeate	Cream
						1	Strong-flavor milk semi-finished product	50kg	18.9kg	1.96kg	9.2kg

Comparative example 1

The comparative example provides a preparation method of strong-flavor milk, which comprises the following steps:

(1) The raw milk is standardized in fat content through a separator, and the protein content and the lactose content are improved through flash evaporation equipment, but the improvement range is limited, so that a semi-finished product before pasteurization is obtained; wherein the fat, protein and lactose contents of raw milk and semi-finished products are shown in tables 11-12:

TABLE 11

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Raw milk	3.8	3.2	4.8

Table 12

Sequence number	Name of the name	Fat	Proteins	Lactose and lactose
					1	Semi-finished product	4.6	3.3	4.9

(2) Pasteurization process: sterilizing the semi-finished product before pasteurization at 85deg.C/15 s, cooling the sterilized cow milk to 1-8deg.C, and storing.

(3) Melting: adding the components such as additive and anhydrous butter into pasteurized milk, stirring, homogenizing at 60deg.C under one-stage homogenizing pressure of 150bar or two-stage homogenizing pressure of 30/150bar.

(4) Ultrahigh temperature sterilization process

4.1 vacuum degassing: vacuum degree-50 kpa.

4.2 homogenizing: the homogenizing temperature is 70-75deg.C, homogenizing pressure is 250bar for the first stage and 50bar for the second stage.

4.3, ultra-high temperature sterilization: 138 ℃/4s.

4.4 cooling: cooling the semi-finished product after the ultrahigh temperature sterilization to be less than or equal to 30 ℃.

5. And (3) filling process: stable production is carried out, and the detection particle size value is about 0.8 mm.

6. The packaging process comprises the following steps: and (5) boxing and code spraying.

Comparative example 2

The comparative example provides a preparation method of strong-flavor milk, and the specific steps are the same as those of comparative example 1, and only the following indexes are different:

the fat, protein and lactose content of the semi-finished product are shown in table 13:

TABLE 13

Performance measurement

The aroma type milk prepared in the above examples 1 to 3 and comparative examples 1 to 2 was subjected to a taste test and a product stability test, specifically as follows:

1. taste test of the product:

2 finished product samples with the physical and chemical indexes close to each other, which are prepared in the example 1 and the comparative example 1, are taken for carrying out a taste experiment. Performing an experiment in a sequencing mode, taking a sample of the comparative example 1 as a standard sample, marking the standard sample as No. 1, taking a sample of the example 1 as an experimental sample, marking the standard sample as No. 2, and performing the steps of marking the standard sample according to No. 1 and No. 2; 2# and 1#;1# and 2#; the cycle sequence of # 2 and # 1 was carried out for 100 persons (50 persons for men and women each of 25 to 35 years old) and the taste results showed that 60 persons of 100 persons liked example 1 (no additive, no anhydrous cream), 40 persons liked comparative example 1 (additive, no anhydrous cream), and more than half of the persons liked comparative example 1 according to the taste rule, so that the taste of example 1 was judged to be input to comparative example 1, and thus the product produced by the process of example 1 was not input to comparative example 1 in terms of both taste and flavor, and mass production was possible.

The same taste experiment is carried out on the products prepared in the example 1 and the comparative example 2, and the final result shows that the products prepared in the process of the example 1 are not different from the products prepared in the comparative example 2 in taste and flavor, and can be produced in batches; the products of example 2 and example 3, which had protein contents higher than those of comparative examples 1-2 and had a taste higher than those of comparative examples 1-2, were also capable of mass production.

2. Product stability test experiment:

the products prepared in examples 1-3 and comparative examples 1-2 were respectively poured into 250ml of Lile brick packages for stability test, the protein content of the products in examples 1-3 was 3.3%,4.5%,6.0%, the protein content of the products in comparative examples 1-2 was 3.3%,3.5%, the fat content was 4.6%, the dry matter content was not less than 12%, and the products were left standing at room temperature (about 20-30 ℃) and under the acceleration condition of oven at 40-45 ℃ respectively, and the products were observed for different times (at room temperature, 1 month, 2 months, 4 months, 6 months, at 40-45 ℃ for acceleration of oven at 1 month, 2 months) for fat floating up (at the stationary state, the thickness of fat layer on the surface of feed liquid was measured with vernier calipers with accuracy of 0.5 mm), and whether there were fat clumps, the tissue state was layered, flocculation, water separation were observed, and the stability of the products was examined.

The specific experimental results are shown in the following table (wherein, the normal temperature observation results are shown in table 14, and the 40-45 ℃ acceleration observation results are shown in table 15):

TABLE 14

TABLE 15

From the above results, it can be seen that the product of example 1 has a uniform tissue state and only a small amount of fat floats up after being stored for 6 months at normal temperature and accelerated for 2 months at 45 ℃, which indicates that example 1 can ensure that the product has no fat caking and no serious fat floating up phenomenon within 6 months.

In summary, the milk components adopted by the invention are subdivided and recombined and homogenized under high pressure, so that the concentrated-flavor milk product of raw milk with different protein contents, different fats and different lactose content ingredients can be prepared, the product can meet the requirements of different consumers in the market (such as people who like concentrated-flavor milk taste and avoid additives and anhydrous cream), the fat does not seriously float and agglomerate in the ultra-long shelf life, and the mellow and concentrated taste of the product can be ensured.

The foregoing is only a preferred embodiment of the present invention. It will be understood that various modifications, combinations, alterations, or substitutions of the details and features of the invention may be made by those skilled in the art without departing from the spirit and nature of the invention. Such modifications, combinations, variations, or alternatives are also to be understood as being included within the scope of the invention as claimed.

Claims (10)

1. The preparation method of the aroma type milk is characterized by comprising the following steps of:

(1) Fat separation: fat separation is carried out on raw milk to obtain cream and skimmed milk;

(2) Ultrafiltration: performing ultrafiltration operation on the skimmed milk to obtain ultrafiltration trapped fluid and ultrafiltration permeate;

(3) Reverse osmosis: performing reverse osmosis operation on the ultrafiltration permeate to obtain reverse osmosis trapped fluid and reverse osmosis permeate;

(4) And (3) component recombination: and mixing the ultrafiltration trapped fluid, the reverse osmosis permeate and the cream.

2. The method according to claim 1, further comprising a step of performing a first sterilization of the cream and the skim milk, respectively, between the step (1) and the step (2), wherein the first sterilization is performed at a temperature of 72 to 90 ℃ for a time of 12 to 17 seconds.

3. The method according to claim 1, wherein the skim milk is subjected to ultrafiltration operation through an ultrafiltration membrane, and the temperature at which the skim milk enters the ultrafiltration membrane is 1-12 ℃.

4. A method of preparation according to claim 3 wherein the ultrafiltration membrane has a pore size of 5000-10000 daltons.

5. The method according to claim 1, wherein the ultrafiltration permeate is subjected to reverse osmosis operation through a reverse osmosis membrane, and the ultrafiltration permeate enters the reverse osmosis membrane at a temperature of 1-12 ℃.

6. The method of claim 1, further comprising sequentially homogenizing and a second sterilization operation after the reconstitution of the components.

7. The method according to claim 6, wherein the homogenizing temperature is 40-80 ℃, the primary homogenizing pressure is 180-400bar, and the secondary homogenizing pressure is 50-100bar.

8. The method according to claim 6, wherein the second sterilization is performed at 137-142 ℃ for 2-5 seconds, and the first-stage homogenization pressure used in the second sterilization is 250-400bar, and the second-stage homogenization pressure is 50-100bar.

9. The preparation method according to claim 1, wherein the mass ratio of the ultrafiltration retentate, the reverse osmosis permeate and the cream is (3-20): (1.5-25): (0-10): (0-10).

10. A flavored milk prepared by the preparation method according to any one of claims 1 to 9.