Instant coffee powder and preparation method thereof
Through electrostatic spray drying technology, the coffee extract is dried at low temperature, which solves the problems of flavor loss and high cost in the production of instant coffee, and improves flavor retention and production efficiency. The instant coffee powder particles produced are uniform and complete, and have a wide range of applicability.
Patent Information
- Application Number
- CN202510699118.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-07-11
AI Technical Summary
The existing instant coffee production process leads to serious loss of coffee flavor components during high-temperature spray drying, and the production cost is high. The freeze-drying technology has problems of low production capacity and high cost, making it difficult to achieve large-scale commercial application.
The electrostatic spray drying technology is used to apply static charge during the spray drying of the coffee extract solution, control the inlet and outlet air temperature between 80-95℃ and 45-55℃, and use inert gas as atomization and drying gas to reduce the concentration requirements of the coffee liquid, and optimize the spray drying parameters to maintain flavor and improve production efficiency.
Quickly dry the coffee liquid into powder at lower temperatures, effectively retaining the original flavor of the coffee, reducing energy consumption, improving production efficiency, and obtaining instant coffee powder with complete and uniform shapes, which is more applicable and cheaper.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of coffee powder, and particularly relates to an instant coffee powder and a preparation method thereof. Background Art
[0002] Instant coffee is a common food raw material in the market. According to GB / T29602 "Solid Beverages", it is defined as: using coffee beans and / or coffee products (ground coffee powder, coffee extract or its concentrated solution) as raw materials, without adding other food raw and auxiliary materials, and food additives can be added, and it is a solid beverage processed through processing. Instant coffee is a kind of coffee solid beverage and an important raw material for instant coffee beverages.
[0003] Most commercially available instant coffee products use raw coffee beans as raw materials and are processed through processes such as roasting, grinding, extraction, concentration, spray drying, and packaging. This traditional production process usually requires concentrating the coffee liquid until the Brix value reaches more than 35, and then performing high-temperature spray drying treatment. However, this process has many deficiencies. Firstly, the high-temperature spray drying process will cause significant loss of heat-sensitive flavor components in the coffee, greatly reducing the flavor quality of the final product and making it difficult to fully restore the rich flavor levels of freshly ground coffee. Secondly, there are high requirements for the Brix value of the concentrated liquid, which to a certain extent limits the selection of raw materials and the flexibility of the process. At the same time, the entire concentration and drying process has high energy consumption. In recent years, the emerging freeze-dried instant coffee technology, although excellent in flavor retention and able to better lock in the original flavor of coffee, has the defects of low production capacity and high manufacturing cost in its production process, which greatly limits the feasibility of its large-scale commercial application.
[0004] Therefore, there is an urgent need in the current instant coffee industry for an innovative production process that can effectively retain coffee flavor while taking into account production efficiency and cost control. Summary of the Invention
[0005] The first object of the present invention is to provide a preparation method for instant coffee powder that can effectively retain coffee flavor and take into account production efficiency and cost control.
[0006] The second object of the present invention is to provide an instant coffee powder prepared by the preparation method as described above.
[0007] To achieve the above object, the technical solution adopted by the present invention is:
[0008] The present invention provides a preparation method for instant coffee powder, which includes the following steps:
[0009] (1) Roast and grind coffee beans to obtain ground coffee powder;
[0010] (2) Extract the ground coffee powder with a solvent to obtain a coffee extract.
[0011] (3) Feed the coffee extract into an electrostatic spray drying device to atomize the coffee extract into droplets, apply electrostatic charges to the droplets within the range of 10 kV to 20 kV, and dry the droplets with electrostatic charges under the conditions that the inlet air temperature is 80 - 95 °C and the outlet air temperature is 45 - 55 °C.
[0012] By applying electrostatic charges during the spray drying process of the coffee extract, the present invention can quickly dry the coffee liquid into powder at a relatively low temperature, which not only avoids the destruction of coffee flavor components by high temperature but also reduces the residence time during the drying process of the coffee liquid, further reducing the loss of flavor components and enabling the coffee powder to better retain the original flavor of coffee. Compared with the traditional process, too low a coffee liquid concentration (< 35 Brix) will cause problems such as incomplete drying and sticking to the tower. The method of the present invention has no excessive restrictions on the concentration of the coffee liquid before drying and has a wider applicability. In addition, the instant coffee powder prepared by the method of the present invention has a complete and uniform particle morphology, which is helpful for dissolution and dispersion during brewing.
[0013] Preferably, electrostatic charges are applied to the droplets within the range of 13 - 17 kV. Excessive electrostatic voltage will cause too strong electrostatic repulsion between droplets, affecting the uniform distribution of the spray and ultimately affecting the drying effect and the quality of coffee powder particles; while too small an electrostatic voltage will cause the droplets to be unable to disperse evenly during the spraying process, easily resulting in incomplete drying and forming sticky particles. Therefore, the electrostatic voltage is preferably within the range defined in the present invention.
[0014] Preferably, before atomizing the coffee extract into droplets, the coffee extract is fed into the spray drying device at a feeding rate of 0.01 - 0.05 L / min. Too large a feeding rate of the coffee extract will cause uneven spraying, forming too large a liquid that cannot evaporate the solvent in time during the drying process, resulting in incomplete drying; while too small a feeding rate will affect the continuity of the drying process, resulting in uneven coffee powder particles. Therefore, it is preferably within the range defined in the present invention.
[0015] More preferably, before atomizing the coffee extract into droplets, the coffee extract is fed into the spray drying device at a feeding rate of 0.015 - 0.03 L / min.
[0016] Preferably, an inert gas is used as the atomizing gas, and the temperature of the atomizing gas is controlled to be 50 - 55 °C and the pressure is 250 - 270 kPa.
[0017] Preferably, an inert gas is used as the drying gas, and the flow rate of the drying gas is controlled to be 25-35 Nm 3 / h.
[0018] Using an inert gas as the atomizing gas and the drying gas can reduce the oxidation of the material and better retain the coffee flavor.
[0019] In some embodiments, the inert gas is nitrogen.
[0020] Preferably, step (2) further includes concentrating the coffee extract so that the concentration of the coffee extract is 10-50 Brix.
[0021] More preferably, the concentration is carried out at 50-70°C and 0.008-0.016 MPa or by membrane concentration, and the process of the membrane concentration refers to the prior art in the field.
[0022] In some embodiments, step (2) specifically includes: feeding the ground coffee powder and the solvent into an extraction tank for extraction, controlling the feeding mass ratio of the ground coffee powder to the solvent to be 1:(5-9), and the extraction pressure is 0.8-1.6 MPa, the temperature is 170-200°C, and the time is 10-45 min.
[0023] Further, control the feeding mass ratio of the ground coffee powder to the solvent to be 1:(6-8), the extraction pressure is 0.8-1.0 MPa, the temperature is 180-190°C, and the time is 35-45 min.
[0024] In some embodiments, step (2) specifically includes: continuously extracting the ground coffee powder with a solvent at 0-6°C under negative pressure, controlling the flow rate of the solvent to be 2-4 L / min, and the extraction pressure is 0.001-0.1 MPa and the time is 4-6 h.
[0025] Further, control the flow rate of the solvent to be 2.5-3.5 L / min, the extraction pressure is 0.001-0.1 MPa and the time is 5-6 h.
[0026] Preferably, the solvent is water.
[0027] Preferably, the particle size of the ground coffee powder is 5-35 mesh.
[0028] The present invention also provides an instant coffee powder prepared by the preparation method as described above.
[0029] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art:
[0030] By applying electrostatic charges during the spray drying process of coffee extract, the present invention can quickly dry the coffee liquid into powder at a relatively low temperature, enabling the coffee powder to better retain the original flavor of coffee. Moreover, the method of the present invention has no excessive restrictions on the concentration of the coffee liquid before drying, with a wider applicability.
[0031] The instant coffee powder prepared by the method of the present invention has a complete and uniform particle morphology, which is helpful for dissolution and dispersion during brewing. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 It is a scanning electron microscope image of the instant coffee powder prepared in Example 1 of the present invention;
[0033] Figure 2 It is a scanning electron microscope image of the instant coffee powder prepared in Comparative Example 1 of the present invention;
[0034] Figure 3 It is a scanning electron microscope image of the frozen coffee powder prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0035] The present invention will be further described below in conjunction with embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions adopted in the embodiments can be further adjusted according to different requirements of specific uses, and the implementation conditions not specified are the conventional conditions in this industry. The technical features involved in various implementation manners of the present invention can be combined with each other as long as they do not conflict with each other.
[0036] Unless otherwise specified, the reagents involved in the following text are all commercially available products or can be prepared by referring to the existing technical methods, and the instruments involved are all conventional instruments in this field. The membrane filtration and membrane concentration processes involved in the following text can be referred to the existing technology.
[0037] Example 1: This example provides a method for preparing instant coffee powder, including the following steps:
[0038] (1) Roast raw coffee beans (Arabica coffee beans) at 200 - 210 °C for 12 - 15 min to obtain roasted coffee beans;
[0039] (2) Grind the above roasted coffee beans on a coffee bean grinder to 5 - 35 mesh to obtain ground coffee powder;
[0040] (3) Send the above ground coffee powder to an extraction tank and extract it with water. Among them, the feeding mass ratio of ground coffee powder to water is 1:7, the extraction temperature is 185 °C, the pressure is 0.9 Mpa, and the time is 38 min to obtain an extract;
[0041] (4) Concentrate the above-mentioned extract under the conditions of 60 - 70 °C and 0.008 - 0.09 Mpa to obtain concentrated coffee liquid, and control the concentration of the concentrated coffee liquid to be 29 Brix (that is, the soluble solid components in the concentrated coffee liquid account for 29% of the total weight of the solution);
[0042] (5) Transmit the above-mentioned concentrated coffee liquid to an electrostatic spray device (Spraying Systems Co. (Shanghai) Co., Ltd., model PD001) through a high-pressure pump for electrostatic spray drying. Among them, the feeding speed of the concentrated coffee liquid is 0.02 L / min, the atomizing gas is nitrogen, the temperature is 52 °C, the pressure is 260 kPa, a voltage of 14 kV is applied at the nozzle at the top of the electrostatic spray device, and the drying gas is nitrogen, the flow rate is 30 Nm 3 / h, the inlet air temperature is 90 °C, and the outlet air temperature is 47 °C;
[0043] (6) Collect the powder particles from the finished product chamber of the electrostatic spray device, which is the instant coffee powder.
[0044] See Figure 1 , the instant coffee powder prepared in Example 1 has a complete particle morphology, less collapse, uniform particles, and wrinkles or depressions on the surface, which is beneficial to reducing the adhesion force between particles and improving fluidity and dispersibility.
[0045] Example 2: This example provides a method for preparing instant coffee powder, which is basically the same as Example 1, except for: steps (4) and (5).
[0046] Step (4) specifically is: Concentrate the extract obtained in step (3) under the conditions of 55 - 70 °C and 0.08 - 0.10 Mpa to obtain concentrated coffee liquid with a concentration of 46 Brix.
[0047] Step (5) specifically is: Transmit the above-mentioned concentrated coffee liquid to an electrostatic spray device through a high-pressure pump for electrostatic spray drying. Among them, the feeding speed of the concentrated coffee liquid is 0.025 L / min, the atomizing gas is nitrogen, the temperature is 52 °C, the pressure is 260 kPa, a voltage of 15 kV is applied at the nozzle at the top of the electrostatic spray device, and the drying gas is nitrogen, the flow rate is 30 Nm 3 / h, the inlet air temperature is 90 °C, and the outlet air temperature is 46 °C.
[0048] The instant coffee powder prepared in this example has a complete particle morphology, less collapse, uniform particles, and wrinkles or depressions on the surface.
[0049] Example 3: This example provides a method for preparing instant coffee powder, which is basically the same as Example 1, except for: steps (3), (4) and (5).
[0050] Step (3) is specifically as follows: The 120 kg of ground coffee powder obtained in step (2) is pre-wetted with water, and then continuously extracted under negative pressure using water at 0 - 6°C. The flow rate of water is controlled at 3 L / min, the extraction pressure is 0.001 - 0.1 Mpa, and the extraction time is 6 h to obtain an extract.
[0051] Step (4) is specifically as follows: The extract obtained in step (3) is subjected to membrane filtration and membrane concentration to obtain a cold-extracted concentrated coffee solution with a concentration of Brix14.
[0052] Step (5) is specifically as follows: The above cold-extracted concentrated coffee solution is transported to an electrostatic spray device through a high-pressure pump for electrostatic spray drying. Among them, the feeding speed of the concentrated coffee solution is 0.016 L / min, the atomizing gas is nitrogen, the temperature is 52°C, the pressure is 260 kPa, a voltage of 16 kV is applied at the nozzle at the top of the electrostatic spray device, the drying gas is nitrogen, the flow rate is 25 Nm 3 / h, the inlet air temperature is 90°C, and the outlet air temperature is 43°C.
[0053] The instant coffee powder prepared in this example has a complete particle morphology, less collapse, uniform particles, and its surface shows wrinkles or depressions.
[0054] Comparative Example 1: This comparative example provides a method for preparing instant coffee powder, which is basically the same as Example 1, except that: in step (5), no voltage is applied, and a conventional spray drying process is used.
[0055] See Figure 2 , the instant coffee powder prepared in Comparative Example 1 has more broken and uneven particles.
[0056] Comparative Example 2: This comparative example provides a method for preparing instant coffee powder, which is basically the same as Example 1, except that: steps (5) and (6).
[0057] Step (5) is specifically as follows: The concentrated coffee solution is poured into a freezer and quickly frozen to -36°C to form a solid, and then ground into small particles or powder.
[0058] Step (6) is specifically as follows: The coffee particles or powder ground in step (5) are placed in a vacuum dryer for freeze-drying at a temperature of -36°C for 32 h to finally obtain freeze-dried coffee powder.
[0059] See Figure 3 , the freeze-dried particles show an irregular morphology and different sizes.
[0060] The above has described the present invention in detail, aiming to enable those skilled in the art to understand the content of the present invention and implement it. However, it should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims
1. A method for preparing instant coffee powder, characterized in that, Comprising the following steps: (1) Roast and grind coffee beans to obtain ground coffee powder; (2) Extract the ground coffee powder with a solvent to obtain a coffee extract; (3) Feed the coffee extract into an electrostatic spray drying device to atomize the coffee extract into droplets, apply electrostatic charges to the droplets within the range of 10 kV to 20 kV, and dry the droplets with electrostatic charges under the conditions that the inlet air temperature is 80 - 95 °C and the outlet air temperature is 45 - 55 °C.
2. The preparation method of the instant coffee powder according to claim 1, characterized in that, Before atomizing the coffee extract into droplets, feed the coffee extract into the spray drying device at a feed rate of 0.01 - 0.05 L / min.
3. The preparation method of the instant coffee powder according to claim 1, characterized in that, Use an inert gas as the atomizing gas, and control the temperature of the atomizing gas to be 50 - 55 °C and the pressure to be 250 - 270 kPa.
4. The preparation method of the instant coffee powder according to claim 1, characterized in that, Use an inert gas as the drying gas and control the flow rate of the drying gas to be 25 - 35 Nm 3 / h.
5. The method for preparing instant coffee powder according to claim 3 or 4, characterized in that, The inert gas is nitrogen.
6. The preparation method of the instant coffee powder according to claim 1, characterized in that, Step (2) further includes concentrating the coffee extract to make the concentration of the coffee extract 10 - 50 Brix.
7. The method for preparing instant coffee powder according to claim 1, characterized in that, Step (2) specifically includes: feeding the ground coffee powder and the solvent into an extraction tank for extraction, controlling the feeding mass ratio of the ground coffee powder to the solvent to be 1:(5 - 9), the extraction pressure to be 0.8 - 1.6 MPa, the temperature to be 170 - 200 °C, and the time to be 10 - 45 min.
8. The preparation method of instant coffee powder according to claim 1, characterized in that, Step (2) specifically includes: continuously extracting the ground coffee powder with a solvent at 0 - 6 °C under negative pressure, controlling the flow rate of the solvent to be 2 - 4 L / min, the extraction pressure to be 0.001 - 0.1 MPa, and the time to be 4 - 6 h.
9. The method for preparing instant coffee powder according to any one of claims 1, 7, and 8, characterized in that, The solvent is water.
10. An instant coffee powder, characterized in that, The instant coffee powder is prepared by the preparation method according to any one of claims 1 to 9.