A process and system for concentrating animal milk

Abstract

The present invention relates to the technical field of dairy product processing, and specifically discloses a process and a system for efficiently and low-energy-consuming concentrating animal milk. The process comprises the following steps: a. at 4-80 °C, adding disodium dihydrogen pyrophosphate and calcium chloride to animal milk and then mixing evenly, and centrifugally separating to obtain supernatant I and precipitate I at the lower layer. The proportion of disodium dihydrogen pyrophosphate added to the animal milk is 0.10-0.80 g / 100 mL; the proportion of calcium chloride added to the animal milk is 0.40-2.95 g / 100 mL. The corresponding system device is simple, economical and environmentally friendly. The process of the present invention can achieve low energy consumption, low investment, small floor area, environmental friendliness, and more effectively reduces the cumbersome process in the existing production, saves time exponentially, efficiently obtains the target product, and has good industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of dairy product processing, and particularly relates to a process and a system for concentrating animal milk. Background Art

[0002] Milk powder produced from raw materials such as animal milk is a commonly used nutritional product in people's daily lives. The most common animal milks include cow milk, goat milk, etc. The annual milk powder production in China is hundreds of thousands of tons. Currently, the main technical methods for producing milk powder are wet process and dry process. The main process of the wet process: raw milk - milk clarification - sterilization - standardization and batching - homogenization - concentration - spray drying - secondary drying - packaging. In the "concentration" link, vacuum evaporation technology is basically adopted to evaporate the water in cow milk and goat milk, and the concentrated substance is obtained by concentrating 3 - 4 times, with a dry matter content of about 45% and a temperature of about 50°C. The main process of the dry process: raw and auxiliary materials - feeding - batching (premixing) - feeding - mixing - packaging. The production of its raw and auxiliary materials also requires the concentration of raw materials such as cow milk and goat milk, and vacuum evaporation technology is also adopted. It can be seen that the concentration of raw milk is an indispensable link in milk powder production.

[0003] In the existing raw milk concentration link, the vacuum evaporation technology has the following problems: 1. High investment in vacuum evaporation equipment and large floor area; 2. High energy consumption. On the one hand, the vacuum technology has high energy consumption; on the other hand, during the operation process, the raw milk needs to be kept at a certain temperature all the time, such as 50°C, with a large temperature difference from the ambient temperature, consuming a large amount of energy; 3. Long operation time. The water in the raw milk is gradually evaporated by vacuum evaporation to obtain concentrated milk with a concentration of 3 - 4 times, and the duration is very long, generally 50 - 60 minutes.

[0004] The existing methods do not have a better process to solve the above technical problems, and there is an urgent need for those skilled in the art to develop new technical methods. Summary of the Invention

[0005] In order to solve the problems described above, the present application provides a process and a system for efficiently and low - energy - consuming concentrating animal milk, which include the following steps: a. At 4 - 80°C, sodium acid pyrophosphate and calcium chloride are added to the animal milk and then mixed evenly, and then centrifuged to obtain supernatant I and precipitate I at the lower layer. The proportion of sodium acid pyrophosphate added to the animal milk is 0.10 - 0.80 g / 100 mL; the proportion of calcium chloride added to the animal milk is 0.40 - 2.95 g / 100 mL.

[0006] For the above - mentioned technical solution, further preferably, the process further includes the following steps:

[0007] b. After the supernatant I is heated, sodium acid pyrophosphate and calcium chloride are added, and then centrifuged to obtain supernatant II and precipitate II at the lower layer;

[0008] c. Combine the lower precipitate I and the lower precipitate II into the harvested concentrated animal milk.

[0009] For the technical solution described above, in every 100 mL of the animal milk, it contains 2.0 - 5.0 g of protein, preferably 2.5 - 4.0 g, and most preferably 3.0 - 3.5 g; it contains 2.0 - 5.5 g of fat, preferably 2.5 - 4.5 g, and most preferably 3.0 - 4.0 g; the animal milk contains 4.0 - 5.5 g of carbohydrates, preferably 4.5 - 5.0 g; further preferably, every 100 mL of the animal milk contains the main nutrients: energy 253 - 284 kJ, protein 3.0 - 3.2 g, fat 3.3 - 4.0 g, carbohydrates 4.7 - 4.8 g, and in addition, it also includes 53 - 70 mg of sodium and 100 - 120 mg of calcium.

[0010] The mass (dry weight) of the concentrated animal milk harvested by using the process of the present invention accounts for 50 - 90 wt% of the mass (dry weight) of the dry matter in the animal milk; further preferably 55 - 85 wt%; most preferably 60 - 82 wt%; the mass of protein in the harvested concentrated animal milk accounts for 70 - 98 wt% of the mass of protein in the animal milk; further preferably 80 - 95 wt%; most preferably 85 - 95 wt%.

[0011] For the technical solution described above, further preferably, the animal milk includes milk, goat milk, and / or camel milk, and any other animal milk used for preparing milk powder is also acceptable.

[0012] For the technical solution described above, further preferably, the proportion of sodium acid pyrophosphate added to the animal milk is 0.11 - 0.56 g / 100 mL, and more preferably, the proportion of sodium acid pyrophosphate added to the animal milk is 0.22 - 0.56 g / 100 mL.

[0013] For the technical solution described above, further preferably, the proportion of calcium chloride added to the animal milk is 0.42 - 1.67 g / 100 mL, which is obtained by converting 0.25 - 1.00 mL / 40.0 mL given in the examples to 0.625 mL (0.42 g) - 2.50 mL (1.67 g) / 100.0 mL; more preferably, the proportion of calcium chloride added to the animal milk is 0.83 - 1.67 g / 100 mL, which is obtained by converting 0.50 - 1.00 mL / 40.0 mL given in the examples to 1.25 mL (0.83 g) - 2.50 mL (1.67 g) / 100.0 mL.

[0014] For the technical solution described above, further preferably, the proportion of disodium dihydrogen pyrophosphate added to the supernatant I in step b is 0.04 - 0.45 g / 100 mL of supernatant I; more preferably, the proportion of disodium dihydrogen pyrophosphate added to the supernatant I in step b is 0.11 - 0.27 g / 100 mL of supernatant I. In the most preferred case, the proportion of disodium dihydrogen pyrophosphate added to the supernatant I in step b is 0.20 - 0.25 g / 100 mL.

[0015] For the technical solution described above, further preferably, the proportion of calcium chloride added to the supernatant I in step b is 0.25 - 1.25 g / 100 mL. More preferably, the proportion of calcium chloride added to the supernatant I in step b is 0.33 - 0.83 g / 100 mL. Most preferably, the proportion of calcium chloride added to the supernatant I in step b is 0.42 - 0.66 g / 100 mL.

[0016] For the technical solution described above, further preferably, the temperature is 4 - 60 °C, and the most preferred temperature is 4 - normal temperature in step a, more preferably 4 - 10 °C, most preferably 4 - 5 °C, and the temperature in step b is 50 - 60 °C, most preferably 50 - 55 °C.

[0017] For the technical solution described above, further preferably, the centrifugation conditions in steps a and c are: centrifugal force 500 - 7800 g, centrifugation time 1.0 - 15.0 min;

[0018] Another aspect of the present invention lies in protecting a system that can be used for the process of efficiently and low - energy - consuming concentrating animal milk; the system only needs to utilize simple centrifugal separation equipment to add calcium chloride and disodium dihydrogen pyrophosphate to animal milk, and under the condition of low investment cost, more lower - layer precipitates (i.e., dry matter) can be harvested from animal milk for subsequent processing into milk powder.

[0019] For the system described above, further, its structure includes: a liquid storage tank, a mixing tank, automatic feeder I and automatic feeder II, and centrifuge I and centrifuge II;

[0020] The mixing tank is connected to automatic feeder I, and the mixing tank is connected to centrifuge I through a pipeline; the centrifuge I is provided with a supernatant I output port and a lower - layer precipitate I collection port, and the supernatant I output port is connected to the downstream liquid storage tank through a pipeline;

[0021] The outer layer of the liquid storage tank is provided with a heating layer. The upstream of the liquid storage tank is also connected to an automatic feeder II through a pipeline. The reagent in the automatic feeder II is quantitatively transported into the liquid storage tank. A centrifuge II is arranged downstream of the liquid storage tank. The centrifuge II is provided with an upper clear liquid II output port and a lower precipitate II collection port;

[0022] For the system described above, further, both the automatic feeder I and the automatic feeder II are respectively provided with a drug metering pump, which can measure the amount of drugs output according to the liquid volume in the mixing tank or II (adding disodium dihydrogen pyrophosphate and calcium chloride). The metering rules of the automatic feeder I and the automatic feeder II are the same as the previous metering rules (adding disodium dihydrogen pyrophosphate and calcium chloride to animal milk).

[0023] For the system described above, further, the temperature of the mixing tank is 4 - 80 °C, more preferably 4 - 60 °C, most preferably 4 °C - normal temperature, more preferably 4 - 10 °C, most preferably 4 - 5 °C; the temperature of the liquid storage tank is 50 - 60 °C, most preferably 50 - 55 °C.

[0024] For the system described above, further, stirring paddles are arranged in both the mixing tank and the liquid storage tank for mixing the liquid materials;

[0025] For the system described above, it should be further noted that: the automatic feeder set in this system is used to add the pre-prepared reagent into the animal milk ( Figure 2 ), because the milk powder production process is basically a continuous process, and the amount of reagent added to the animal milk needs to be based on the volume or flow rate of the animal milk.

[0026] For the system described above, it should be further noted that: the types of the centrifuges I and II set in this system are not limited, as long as they can be used to achieve the centrifugation effect in industry. For example, common horizontal centrifuges or disc centrifuges can be used, etc.

[0027] For the system described above, it should be further noted that: the heating layer of the liquid storage tank set in this system is used to heat the upper clear liquid II; the type of the heating equipment is also not limited, as long as it can be used to achieve the heating effect in industry. After heating, as the temperature decreases, the subsequent damage to protein nutrition decreases.

[0028] For the system described above, the specific process implemented is:

[0029] The raw animal milk liquid is transported through a pipeline to a mixing tank set downstream. The reagent in the automatic feeder I is quantitatively transported into the mixing tank. After the animal milk and the reagent are fully mixed in the mixing tank, they are input through a pipeline into a centrifuge I set downstream for centrifugation to obtain supernatant I and precipitate I respectively. The precipitate I is collected as raw material for milk powder; the supernatant I is transported to a storage tank.

[0030] After the supernatant I is heated to 50 - 60 °C in the storage tank and then separated by a centrifuge II, supernatant II and precipitate II are obtained; the supernatant II is collected through a pipeline for use as subsequent water-soluble fertilizer material; the precipitate II is collected as raw material for milk powder.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) Low energy consumption. The existing production process for concentrating milk uses vacuum evaporation technology, which not only has high equipment investment, large floor area, but also high energy consumption. First, the vacuum technology has high energy consumption; second, during the operation, the raw milk needs to be kept at a certain temperature, such as 50 °C, consuming a large amount of energy. The present invention only adds disodium dihydrogen pyrophosphate and calcium chloride to animal milk, reducing the cumbersome process in the existing production.

[0033] (2) Time saving. The method of the present invention uses secondary centrifugal separation and concentration, with each centrifugation time of 3 min; however, the existing production process (vacuum evaporation for concentrating milk) requires about 50 - 60 min. It can be seen that the method of the present invention saves time by several times.

[0034] (3) It can be operated at room temperature, and the effective components in the protein are not damaged. The first step of the present invention is operated at room temperature, concentrating more than 90% of the protein. Only the supernatant I produced in the first step is heated to 50 °C to obtain a small amount of additional protein (3.33%). Therefore, most of the dry matter harvested by the method of the present invention is completed at room temperature, meaning that most of the protein does not lose its effective components due to heating.

[0035] (4) The protein and carbohydrates (total sugar) in animal milk are preliminarily separated. More than 94% of the protein in animal milk is harvested in precipitate I and II, while more than 60% of the total sugar in animal milk is harvested in supernatant II. Description of the Drawings

[0036] Figure 1 It is a new process flow chart for efficiently obtaining concentrated milk from animal milk.

[0037] Figure 2 It is a new process system structure diagram for efficiently obtaining concentrated milk from animal milk.

[0038] Figure 3Partial experimental centrifugation effect diagram of experimental group 3 in Example 1, as shown in the figure: Figure 3-1 From left to right are experimental groups 3-2-1, 3-2-1, 3-2-3, and 3-2-4; Figure 3-2 From left to right are 3-2-5, 3-3-3, 3-3-2, and 3-3-1. It can be analyzed from the centrifugation comparison diagram that the centrifugation separation effects of groups 3-2-1 and 3-3-1 with a calcium chloride addition amount of 0.10 mL are relatively poor, and the separation effects of other groups are good.

[0039] Figure 4 Partial experimental centrifugation effect diagram of Example 2, as shown in the figure: Figure 4-1 4-2 and 4-3 are respectively the centrifugation separation effect diagrams of experimental group 2 (60 °C), experimental group 4 (20 °C), and experimental group 5 (4 °C). It can be seen that good separation effects are achieved for animal milk at 4 °C, 20 °C, and 60 °C using the method of the present invention.

[0040] Figure 5 For the supernatant I obtained from experimental group 3 in Example 1, the method of centrifuging the supernatant I in Example 4 is used to obtain the experimental effect diagram of supernatant II and lower precipitate II. Figure 5-1 They are parallel samples numbered ① - ⑥. Sample ⑦ is the remaining supernatant I with a volume less than 40.0 mL, but reagents are also added proportionally and then centrifuged. This figure is the overall experimental effect diagram; Figure 5-2 5-1 and 5-3 are respectively the enlarged effect diagrams of samples ① and ②, and samples ④ and ⑤. It can be seen that the separation effect is very obvious, and the separated supernatant II is clear and transparent.

[0041] Figure 6 Experimental effect diagram of separating 400.0 mL of animal milk in Example 4. Figure 6-1 Effect diagram of centrifuging 400.0 mL of animal milk; Figure 6-2 Experimental effect diagram of supernatant II and lower precipitate II produced by centrifuging supernatant I. Detailed implementation method

[0042] The following combines the attached drawings to describe the detailed implementation method of the present invention in detail, but it should be understood that the protection scope of the present invention is not limited by the detailed implementation method.

[0043] In the present invention, unless otherwise clearly stated, percentages and percentage contents are based on mass. Without special instructions, the experimental methods used are all conventional methods, and the materials, reagents, etc. used can be purchased from commercial channels.

[0044] All reagents used in the examples of the present invention are food grade, and the water used is sterilized deionized water.

[0045] All the "sodium acid pyrophosphate" used in the embodiments of the present invention is an abbreviation, which refers to an aqueous solution of sodium acid pyrophosphate with a concentration of 0.8 M; all the "calcium chloride" is also an abbreviation, which refers to an aqueous solution of calcium chloride with a concentration of 6.0 M.

[0046] In the specific implementation manner of the present invention, the milk is obtained through commercial channels, and its protein content is between 3.0 - 3.3 / 100.0 mL; the samples of each batch are experimented separately without mixing, and the experimental effects are similar. There are 3 parallel samples in each group, expressed as: mean ± standard deviation, and the one-way analysis of variance method is used.

[0047] I. Milk used in the experiment

[0048] 1. Milk - Mengniu pure milk, premium pack, net content 200 mL;

[0049]

[0050] 2. Milk - Xinle pasteurized fresh milk, family pack, net content 442 mL, Dalian Xinle Dairy Co., Ltd.;

[0051]

[0052]

[0053] 3. Milk - Sanhuan pure milk, family pack, net content 442 mL, Dalian Sanhuan Dairy Co., Ltd.;

[0054]

[0055] II. Goat milk used in the experiment

[0056] Goat milk - Shepherd A2β - casein pure goat milk, net content 200 mL;

[0057]

[0058] Example 1. Influence of reagent addition amount on the centrifugal concentration effect of milk

[0059] (1) Experimental process

[0060] a. Influence of adding different doses of reagents to milk on the milk concentration effect

[0061] 117 plastic centrifuge tubes, with every 3 centrifuge tubes as a group and used as parallel samples, divided into 39 groups.

[0062] There are 3 groups in the blank group. 9 centrifuge tubes are each added with 40.0 mL of sterilized water. To every 3 centrifuge tubes are respectively added 1.25 mL of 0.8 M disodium dihydrogen pyrophosphate, 1.00 mL of 6.0 M calcium chloride, and the reagent combination (1.25 mL of 0.8 M disodium dihydrogen pyrophosphate + 1.00 mL of 6.0 M calcium chloride), serving as blank groups 1, 2, and 3 respectively.

[0063] There is 1 group in the control group. 40.0 mL of milk is added to each of the 3 centrifuge tubes.

[0064] There are 5 groups in experimental group 1. 40.0 mL of milk is added to each of the 15 centrifuge tubes. Then, to every 3 centrifuge tubes are respectively added 0.25 mL, 0.50 mL, 0.75 mL, 1.00 mL, and 1.25 mL of the reagent 0.8 M disodium dihydrogen pyrophosphate, serving as experimental groups 1-1, 1-2, 1-3, 1-4, and 1-5 respectively.

[0065] There are also 5 groups in experimental group 2. 40.0 mL of milk is similarly added to each of the 15 centrifuge tubes. Then, to every 3 centrifuge tubes are respectively added 0.10 mL, 0.25 mL, 0.50 mL, 0.75 mL, and 1.00 mL of the reagent 6.0 M calcium chloride, serving as experimental groups 2-1, 2-2, 2-3, 2-4, and 2-5 respectively.

[0066] There are 25 groups in experimental group 3. 40.0 mL of milk is added to each of the 75 centrifuge tubes, and then the reagent combination (0.8 M disodium dihydrogen pyrophosphate + calcium chloride) is added. The specific addition amounts of the reagents are shown in Table 1.

[0067] For the above centrifuge tubes, the operation is carried out at room temperature (20 °C), and then centrifugation is performed at 3000 revolutions per minute (1980 g) for 3 minutes. b. Detection of the upper clear liquid I and the lower precipitate I formed after centrifugal concentration of milk

[0068] In the above experiment, two layers, upper and lower, are formed after centrifugal concentration of milk. The upper liquid (referred to as the "upper liquid") is collected and its volume is measured, while the lower precipitate (referred to as the "lower precipitate") is collected and its mass (wet weight) is weighed, and then it is dried to a constant weight at 60 °C and its mass (dry weight) is weighed.

[0069] 40.0 mL of milk and the upper liquid are respectively added to pre-weighed glass petri dishes and weighed (after subtracting the mass of the petri dish, it is called the "wet weight"), and then weighed again after drying to a constant weight at 60 °C (after subtracting the mass of the petri dish, it is called the "dry weight"). There are 3 parallels for each sample.

[0070] For the above-mentioned milk, upper liquid, and lower precipitate, the protein content and total sugar content are respectively detected by the methods of GB 2009.5-2016 and the phenol-sulfuric acid method. If the sample amount is not enough for detection, the experiment is repeated.

[0071] (2) Experimental results

[0072] The mass of 40.0 mL of milk after drying at 60 °C (i.e., the dry matter mass) was 5.40 ± 0.23 g

[0073] As can be seen from the experimental results (Table 1), after centrifugation, no precipitation formed in the blank group, and the milk liquid did not separate into layers, showing no difference from before centrifugation. There was almost no difference in the control group (only milk was added) before and after centrifugation. There was little difference in Experimental Group 1 (sodium acid pyrophosphate added to milk) and Experimental Group 2 (calcium chloride added to milk) before and after centrifugation, with only a slight amount of precipitation at the bottom of the centrifuge tube. In Experimental Group 3 (a reagent combination of sodium acid pyrophosphate and calcium chloride added to milk), obvious stratification occurred after centrifugation (except for the group with 0.10 mL of calcium chloride added), that is, an upper liquid layer and a lower precipitation layer, and in some groups, the upper liquid was semi-transparent; the mass of the lower precipitation (dry weight) increased with the increase in the amount of reagent added, but was basically stable at 70 - 80% of the dry matter mass (5.40 g) of 40.0 mL of milk. Taking the criterion of less reagent addition amount and more harvested lower precipitation mass (dry weight), it can be seen from Table 1 that the reagent combination of 0.75 mL of sodium acid pyrophosphate + calcium chloride (0.25 - 0.50 mL) was the optimal addition dose, that is, adding 0.134 g of sodium acid pyrophosphate + calcium chloride (0.167 g - 0.333 g) to 40.0 mL of milk had the best effect on separating and harvesting the lower precipitation. In summary, it was determined that adding 0.75 mL (0.134 g) of 0.8 M sodium acid pyrophosphate + 0.35 mL (0.233 g) of 6.0 M calcium chloride to 40.0 mL of milk was the optimal ratio and was used for subsequent experiments.

[0074] Table 1. Influence of reagent addition amount on the concentration effect of milk centrifugation (3000 r, 3 min) at room temperature (20 °C)

[0075]

[0076]

[0077] Note: 1. For each experimental group in the blank group, the amount of sterilized water added was 40.0 mL;

[0078] 2. For each experimental group in the control group and experimental groups, the amount of fresh milk added was 40.0 mL;

[0079] 3. The mass of 40.0 mL of fresh milk (dry weight after drying) was 5.40 g ± 0.23 g.

[0080] Example 2

[0081] Effect of temperature on the centrifugation concentration effect of milk under the condition of the optimal reagent addition ratio

[0082] (1) Experimental operation

[0083] a. Take 40.0 mL of milk separately and put it into a glass petri dish, weigh it (after subtracting the mass of the petri dish, it is called "wet weight of 40.0 mL of milk"), and weigh it after drying to constant weight (after subtracting the mass of the petri dish, it is called "dry weight of 40.0 mL of milk" or "dry matter in 40.0 mL of milk"). The mass percentage (dry-wet ratio) of its dry weight (dry matter) to wet weight is calculated according to the following formula:

[0084] (Dry weight of 40.0 mL of fresh milk / Wet weight of 40.0 mL of fresh milk) × 100%

[0085] b. For milk at temperatures of 4 °C, 20 °C, 40 °C, 60 °C, and 80 °C, take 40.0 mL of milk at each of the above temperatures and add them to 6 centrifuge tubes respectively. Among them, 3 centrifuge tubes are used as control groups, and the other 3 centrifuge tubes are added with a reagent combination (0.75 mL of 0.8 M disodium dihydrogen pyrophosphate + 0.35 mL of 6.0 calcium chloride). Then, after centrifuging at 3000 revolutions per minute (1980 g) for 3 minutes, take out the centrifuge tubes and observe;

[0086] c. After centrifugation, first take out the upper layer of liquid and measure its volume, then take out the lower layer of precipitate and weigh it (wet weight), and then dry it to constant weight at 60 °C and weigh it (dry weight), which is also called the dry matter mass of the lower layer of precipitate.

[0087] Table 2. Influence of milk temperature on the separation effect of centrifugation (3000 r, 3 min)

[0088]

[0089] Note: 1. The amount of fresh milk in the experimental group is 40.0 mL;

[0090] 2. The mass of 40.0 mL of fresh milk (dry weight after drying at 60 °C) is 5.09 g ± 0.05 g.

[0091] (2) Experimental results

[0092] The dry matter mass in 40.0 mL of milk is 5.09 ± 0.05 g.

[0093] The results of the mass of the lower - layer precipitate (dry weight) are shown in Table 2. After centrifugation, under each experimental temperature condition, no precipitate was formed in the control - group milk, showing almost no change; however, in the experimental groups, the milk was separated into two layers, the upper - layer liquid and the lower - layer precipitate. The mass of the lower layer (dry weight) is shown in Table 2. As the temperature increased, the mass of the lower - layer precipitate increased, but the increase was not significant. That is, the mass of the lower - layer precipitate (dry weight) of the milk at 4 °C, 20 °C, and 80 °C accounted for 67.98%, 69.35%, and 81.93% of the dry - matter mass in 40.0 mL of milk, respectively. It can be seen that when the milk temperature is between 4 °C and 80 °C, the method of the present invention can efficiently harvest the lower - layer precipitate.

[0094] Example 3

[0095] Effect of centrifugal force and centrifugal time on milk concentration effect under normal temperature (20 °C) and the most suitable reagent - addition ratio

[0096] (1) Experimental setup

[0097] For the experiments with rotational speeds from 1500 rpm (centrifugal force 505 g) to 4000 rpm (centrifugal force 3175 g), 40.0 mL of milk was added to a 50.0 - mL plastic centrifuge tube, and a floor - type centrifuge was used. For the experiment with a rotational speed of 9000 rpm (centrifugal force 7770 g), 8.0 mL of milk was added to a 10.0 - mL plastic centrifuge tube, and a table - top centrifuge was used.

[0098] At normal temperature (20 °C), milk was added to all centrifuge tubes. The group without adding reagents was used as the control group, and the group adding reagents at the ratio of “0.75 mL of disodium dihydrogen pyrophosphate 0.8 M+0.35 mL of calcium chloride 6.0 M” / 40.0 mL of milk was used as the experimental group. According to different centrifugal forces and centrifugal times, it was divided into experimental groups 1 - 5 and the corresponding control groups for each experimental group. The specific experimental design and results are shown in Table 3. After centrifugation, the centrifuge tubes were taken out and observed. The lower - layer precipitate was dried at 60 °C to constant weight and then weighed.

[0099] 40.0 mL of fresh milk was taken and placed in a glass petri dish, weighed (after subtracting the mass of the petri dish, it was called “wet milk weight”), and then dried at 60 °C to constant weight and weighed again (after subtracting the mass of the petri dish, it was called “dry milk weight”).

[0100] (2) Experimental results

[0101] The dry - matter content in 40.0 mL of milk was 5.40±0.23 g.

[0102] As can be seen from Table 3: In the control groups under all experimental conditions, except for a small amount of precipitate formed in control group 1 (centrifugal rotational speed 9000 rpm), no precipitate was formed, and there was almost no difference before and after centrifugation; however, after centrifugation, upper (liquid) and lower (precipitate) layers were formed in all experimental groups.

[0103] The percentage of the mass of the lower layer precipitate (dry weight) in the dry matter content of milk in the experimental groups under different centrifugal force and centrifugal time conditions was 72.04 - 80.56%. It can be seen that at room temperature (20 °C), after adding the reagent combination (sodium acid pyrophosphate + calcium chloride) to milk, a centrifugal force of 505 - 7770 g and a centrifugal time of 1.0 - 15.0 min can efficiently separate milk, and the separation effect is stable. This indicates that the method of the present invention has a good effect on concentrating milk.

[0104] Table 3. Influence of centrifugation conditions (centrifugal force, time) on the milk concentration effect

[0105]

[0106]

[0107] Note: 1. Experimental group "0.8 M sodium acid pyrophosphate 0.75 mL + 6.0 M calcium chloride 0.35 mL" / 40.0 mL fresh milk;

[0108] 2. **, Experiments were conducted on a bench-top high-speed centrifuge, and the milk addition amount in each experimental group was 8.0 mL;

[0109] *, Experiments were conducted on a floor-standing centrifuge, and the milk addition amount in each experimental group was 40.0 mL;

[0110] 3. △ , The mass of 40.0 mL fresh milk (dry weight after drying) was 5.40 g ± 0.23 g. Here, 8.0 mL of fresh milk was used in the experiment, and the percentage of the lower layer precipitate in the dry weight of fresh milk in the experimental group was calculated as follows: lower layer precipitate in the experimental group (dry weight) / [5.40 g × (8.0 mL / 40.0 mL)].

[0111] Example 4. Process of the new method for milk concentration

[0112] Process flow chart of the new method for milk concentration ( Figure 1 )

[0113] (1) Experimental process,

[0114] a. After adding reagents to milk, centrifugal separation is performed to obtain upper layer supernatant I and lower layer precipitate I

[0115] In four plastic centrifuge bottles, add 400.0 mL of milk respectively, and add reagents (in the proportion of adding "7.50 mL of 0.8 M disodium dihydrogen pyrophosphate + 3.50 mL of 6.0 M calcium chloride" to 400.0 mL of milk), centrifuge at 3000 revolutions per minute (1980 g) for 3 minutes, and it is divided into upper and lower layers. Collect the upper-layer liquid (referred to as "upper-layer liquid I") and measure its volume, and at the same time collect the lower-layer precipitate (referred to as "lower-layer precipitate I") and weigh its mass (wet weight), and then dry it to a constant weight at 60 °C and weigh its mass (dry weight).

[0116] b. After adding reagents to the upper-layer liquid I, centrifuge it to separate into upper-layer supernatant II and lower-layer precipitate II

[0117] After mixing the upper-layer liquid I, add reagents (in the proportion of adding "0.50 mL of 0.8 M disodium dihydrogen pyrophosphate + 0.25 mL of 6.0 M calcium chloride" to 40.0 mL of the upper-layer liquid I), stir evenly, and then centrifuge at 3000 revolutions per minute (1980 g) for 3 minutes, and it is divided into upper and lower layers. Collect the upper-layer liquid (referred to as "upper-layer supernatant II") and measure its volume, and at the same time collect the lower-layer precipitate (referred to as "lower-layer precipitate II") and weigh its mass (wet weight), and then dry it to a constant weight at 60 °C and weigh its mass (dry weight).

[0118] c. Index detection of samples such as the above-mentioned milk, lower-layer precipitates I and II, upper-layer liquid I and upper-layer supernatant II

[0119] Respectively take 40.0 mL of milk, upper-layer supernatants I and II and add them to pre-weighed glass petri dishes, weigh them (after subtracting the mass of the petri dish, it is called "wet weight"), and weigh them after drying to a constant weight at 60 °C (after subtracting the mass of the petri dish, it is called "dry weight"). There are 3 parallels for each sample.

[0120] Use the methods of GB 5009.5-2016 and phenol-sulfuric acid method to detect the protein content and total sugar content of samples such as the above-mentioned milk, upper-layer supernatants I and II, lower-layer precipitates I and II.

[0121] (2) Experimental results

[0122] In the above experimental process, 400.0 mL of milk was centrifuged and separated, and the experimental results were all converted into the subsequent materials, their dry matter, and the amount of protein produced by 1 400.0 mL of protein water (Table 4).

[0123] Table 4. Material flow chart of the new milk concentration method

[0124]

[0125] 400.0 mL of milk contains 56.4 g of dry matter and 12.0 g of protein. After the first centrifugation at room temperature, it is divided into upper and lower layers. The lower precipitate I contains 37.5 g of dry matter and 10.9 g of protein. The upper liquid I is heated to 50 °C and a reagent is added, and after centrifugation, it is also divided into upper and lower layers. The upper layer is a clear and transparent liquid II, and the lower precipitate II contains 2.0 g of dry matter and 0.4 g of protein. The lower precipitate I and the lower precipitate II are combined, and the amounts of their dry matter and protein account for 70.04% and 94.17% of those in 400.0 mL of milk respectively. It can be seen that although the dry matter content in the milk concentrated by the method of the present invention just exceeds 70%, more than 94% of the protein is concentrated, and the protein content in the concentrated milk is increased, which is very valuable.

[0126] Example 5. Process of the new method for concentrating goat milk

[0127] The process flow chart of the new method for concentrating goat milk is the same as that of milk, Figure 1 except that raw goat milk is used instead of milk.

[0128] (1) Experimental process: The experimental process is the same as that of Example 4 of milk, except that goat milk is used instead of milk because the main nutritional components of goat milk and milk are almost the same.

[0129] (2) Experimental results: In the above experimental process, 400.0 mL of goat milk was centrifuged and separated. The experimental results were all converted into the subsequent materials and their amounts of dry matter and protein produced by 1 400.0 mL of protein water (Table 5).

[0130] Table 5. Material flow chart of the new method for concentrating goat milk

[0131]

[0132] 400.0 mL of goat milk contains 57.6 g of dry matter and 12.8 g of protein. After the first centrifugation at room temperature, it is divided into upper and lower layers. The lower precipitate I contains 39.6 g of dry matter and 11.7 g of protein. After heating the upper liquid to 50 °C and adding a reagent for centrifugation, it is also divided into upper and lower layers. The upper layer is a clear and transparent liquid II, and the lower precipitate II contains 2.3 g of dry matter and 0.5 g of protein. The lower precipitate I and the lower precipitate II are combined, and the amounts of their dry matter and protein account for 72.74% and 95.31% of those in 400.0 mL of milk respectively. It can be seen that although the dry matter content in the goat milk concentrated by the method of the present invention just exceeds 70%, more than 95% of the protein is concentrated, and the protein content in the concentrated goat milk is increased, which is very valuable.

[0133] Example 6

[0134] The above technical solution of the present invention can be realized by the following process system. Only a simple centrifugal separation device is needed to add calcium chloride and disodium dihydrogen pyrophosphate to animal milk. Under the condition of low investment cost, more lower-layer precipitates (i.e., dry matter) can be harvested from animal milk for subsequent processing into milk powder.

[0135] Such as Figure 2 , the system includes: a mixing tank 11, an automatic feeder I 12, a centrifuge I 13, a liquid storage tank 2, an automatic feeder II 21, and a centrifuge II 3;

[0136] The mixing tank 11 is connected to the automatic feeder I 12, and the mixing tank 11 is connected to the centrifuge I through a pipeline; the centrifuge I 13 is provided with an upper-layer clear liquid I output port and a lower-layer precipitate I collection port, and the upper-layer clear liquid I output port is connected to the downstream liquid storage tank 2 through a pipeline;

[0137] The outer layer of the liquid storage tank 2 is provided with a heating layer. The upstream of the liquid storage tank 2 is also connected to the automatic feeder II 21 through a pipeline. The reagent in the automatic feeder II 21 is quantitatively transported into the liquid storage tank 2. The centrifuge II 3 is arranged downstream of the liquid storage tank 2. The centrifuge II 3 is provided with an upper-layer clear liquid II output port and a lower-layer precipitate II collection port;

[0138] The specific process realized by the above connection structure is as follows:

[0139] The raw material liquid of animal milk is transported to the downstream mixing tank 11 through a pipeline. The reagent in the automatic feeder I 12 is quantitatively transported into the mixing tank 11. After the animal milk and the reagent are fully mixed in the mixing tank 11, they are input into the downstream centrifuge I 13 through a pipeline for centrifugation to obtain the upper-layer clear liquid I and the lower-layer precipitate I respectively. The lower-layer precipitate I is collected as the raw material of milk powder; the upper-layer clear liquid I is transported to the liquid storage tank 2.

[0140] After the upper-layer clear liquid I is heated at 50 °C in the liquid storage tank 2 and separated by the centrifuge II 3, the upper-layer clear liquid II and the lower-layer precipitate II are obtained; the upper-layer clear liquid II is collected through a pipeline for use as the subsequent water-soluble fertilizer material; the lower-layer precipitate II is collected as the raw material of milk powder.

[0141] The automatic feeder I 12 and the automatic feeder II 21 are each provided with a medicine metering pump, which can measure the amount of medicine output (adding disodium dihydrogen pyrophosphate and calcium chloride) according to the liquid volume in the mixing tank 11 or II. The metering rules of the automatic feeder I and the automatic feeder II 21 are the same as the previous metering rules (adding disodium dihydrogen pyrophosphate and calcium chloride to animal milk).

[0142] The temperature of the mixing tank 11 of the system is 4 °C; the temperature of the liquid storage tank 2 is 50 °C.

[0143] Stirring paddles are provided in both the mixing tank 11 and the liquid storage tank 2 for mixing the liquid materials.

[0144] The automatic feeder provided in this system is used to add the pre-prepared reagent into the animal milk ( Figure 2 ), because the production process of milk powder is basically a continuous process, and the amount of reagent added to the animal milk needs to be based on the volume or flow rate of the animal milk.

[0145] The types of the centrifuges I 13 and II 3 provided in this system are not limited, as long as they can be used to achieve the centrifugation effect in industry, for example: common horizontal centrifuges or disc centrifuges, etc.

[0146] In addition, the heating layer of the liquid storage tank 2 provided in this system is used to heat the supernatant II; the type of the heating equipment is also not limited, as long as it can be used to achieve the heating effect in industry, and the subsequent separation effect is better as the temperature decreases after heating.

[0147] Example 7

[0148] The applicant conducted experiments with different samples at different times. The raw material samples included experiments on protein water in the production process of fish meal, experiments on soybean protein water, and experiments on the animal milk of this application. The specific grouping and comparison are as follows:

[0149] Experimental group 1: According to the example of Patent 202310242874.7, a new low-energy consumption and environmentally friendly fish meal production process and system

[0150] Experimental group 2: According to the example of Patent 202310304530.4, a method for efficiently harvesting dry matter from soybean protein water;

[0151] Experimental group 3: As in Experimental group 3 of Table 3 of this application form;

[0152] Table 6. Comparison of the main components and centrifugal separation results of milk, soybean protein water, and protein water in fish meal production

[0153]

[0154] It can be seen from the result comparison in Table 6 above that due to the different materials, there are also significant differences in their main components and contents. Therefore, the optimal amounts of reagents added are different, and the separation effects are also different.

[0155] The above content is a further elaboration of the present invention in combination with specific preferred embodiments of the present invention. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For any person skilled in the art, without departing from the technical scope of the present invention, any changes or modifications made will be regarded as being covered within the scope of the claims of the present invention.

Claims

1. A process for concentrating animal milk, characterized in that, it comprises the following steps: a. At 4°C to 20°C, add disodium dihydrogen pyrophosphate and calcium chloride to the animal milk and mix well, then centrifuge to obtain supernatant I and precipitate I at the lower layer; the centrifugation conditions are: centrifugal force 500 - 7800g, centrifugation time 1.0 - 15.0 min; the proportion of disodium dihydrogen pyrophosphate added to the animal milk is 0.10 - 0.80 g / 100 mL; the proportion of calcium chloride added to the animal milk is 0.42 - 1.67 g / 100 mL.

2. The process according to claim 1, characterized in that, the process further comprises the following steps: b. After heating supernatant I, add the reagents disodium dihydrogen pyrophosphate and calcium chloride, and centrifuge to obtain supernatant II and precipitate II at the lower layer; c. Combine precipitate I at the lower layer and precipitate II at the lower layer to obtain the harvested concentrated animal milk.

3. The process according to claim 1, characterized in that, Every 100 mL of animal milk contains: 2.0 - 5.0 g of protein, 2.0 - 5.5 g of fat, and 4.0 - 5.5 g of carbohydrates.

4. The process according to claim 1, characterized in that, the animal milk includes cow milk, goat milk and / or camel milk.

5. The process according to claim 1, characterized in that, the proportion of disodium dihydrogen pyrophosphate added to the animal milk is 0.11 - 0.56 g / 100 mL.

6. The process according to claim 1, characterized in that, the proportion of calcium chloride added to the animal milk is 0.83 - 1.67 g / 100 mL.

7. The process according to claim 2, characterized in that, the proportion of disodium dihydrogen pyrophosphate added to supernatant I in step b is 0.04 - 0.45 g / 100 mL of supernatant I.

8. The process according to claim 2, characterized in that, the proportion of calcium chloride added to supernatant I in step b is 0.25 - 1.25 g / 100 mL.

9. The process according to claim 2, characterized in that, the temperature in step b is 50 - 60°C.

10. The process according to claim 2, characterized in that, the centrifugation conditions in b are: centrifugal force 500 - 7800g, centrifugation time 1.0 - 15.0 min.

11. The process according to claim 1, characterized in that, the structure of the system used in the process includes: a liquid storage tank, a mixing tank, automatic feeder I and automatic feeder II, and centrifuge I and centrifuge II; The mixing tank is connected to automatic feeder I, and the mixing tank is connected to centrifuge I through a pipeline; Centrifuge I is provided with a supernatant I output port and a precipitate I collection port at the lower layer, and the supernatant I output port is connected to the downstream liquid storage tank through a pipeline; The outer layer of the liquid storage tank is provided with a heating layer, and the upstream of the liquid storage tank is also connected to automatic feeder II through a pipeline. The reagents in automatic feeder II are quantitatively transported into the liquid storage tank. A centrifuge II is arranged downstream of the liquid storage tank, and centrifuge II is provided with a supernatant II output port and a precipitate II collection port at the lower layer; The automatic feeder I and the automatic feeder II are respectively provided with medicine metering pumps for controlling the dosage of sodium acid pyrophosphate and calcium chloride; The temperature of the mixing tank is 4°C to 20°C; the temperature of the liquid storage tank is 50 - 60°C.

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