Radio frequency freeze dryer and freeze-drying method applied to edible mushroom biscuit making

Abstract

The invention discloses a radio frequency freeze dryer applied to edible mushroom biscuit making and a freeze-drying method, and relates to the technical field of freeze-drying, the radio frequency freeze dryer comprises an integrated radio frequency source, a first radio frequency polar plate, a second radio frequency polar plate, a vacuum material cavity, a vacuumizing device, a cooling device and a material tray, the first radio frequency polar plate is connected with the integrated radio frequency source, and the second radio frequency polar plate is connected with the second radio frequency polar plate; the second radio frequency polar plate is grounded, the first radio frequency polar plate and the second radio frequency polar plate are arranged in the vacuum material cavity at intervals, the vacuumizing device and the cooling device are both connected with the vacuum material cavity, and the material disc is arranged between the first radio frequency polar plate and the second radio frequency polar plate; the materials are freeze-dried in the two stages of vacuum sublimation drying and desorption drying through radio frequency, heating is conducted from the interior of the materials in the freeze-drying process, the heating efficiency can be improved, energy consumption can be reduced, the radio frequency has the advantage of being high in penetrability, processing of the materials in the multi-layer stacked material disc can be achieved, and the processing efficiency of the materials in the multi-layer stacked material disc is improved. And the production efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of freeze-drying, in particular to a radio frequency freeze-drying machine and freeze-drying method applied to edible mushroom biscuit production. BACKGROUND

[0002] The vacuum freeze-drying machine is called freeze-drying machine, which originates from the vacuum freeze-drying technology. The vacuum freeze-drying technology is to pre-freeze the wet material or solution to be freeze-dried into solid state at a lower temperature (such as 0℃ to-50℃), and then sublimate the water in the solid state into gas state without liquid state under vacuum, so as to finally achieve the dehydration drying technology of the material or solution, which is mainly applied to high-heat-sensitive drugs, food, health products, cosmetics and other products.

[0003] In the edible mushroom biscuit production, freeze-dried shiitake mushroom powder is used, which is made by a freeze-drying machine. The freeze-drying process of the freeze-drying machine mainly includes three stages of pre-freezing, vacuum sublimation drying and desorption drying. The known freeze-drying machine of the applicant includes an ordinary freeze-drying machine and a microwave freeze-drying machine. The ordinary freeze-drying machine uses the heat conduction mode of heat transfer from outside to inside, and the water evaporation is from inside to outside. There is inconsistency in the transmission path, which leads to low heating efficiency and high energy consumption. The microwave freeze-drying machine mainly uses the principle of microwave penetration to heat from the inside in the vacuum sublimation drying and desorption drying stages, so that the water transmission, temperature transmission and humidity transmission are in the same direction. However, due to the physical properties of microwaves, the microwave penetration depth is small, and the material in the multi-layer stacked material tray cannot be processed, which leads to low product processing efficiency.

[0004] Therefore, people urgently need a radio frequency freeze-drying machine applied to edible mushroom biscuit production, which has high heating efficiency, low energy consumption and high production efficiency. SUMMARY

[0005] The purpose of the present application is to provide a radio frequency freeze-drying machine and freeze-drying method applied to edible mushroom biscuit production, so as to solve the problems of the prior art. The freeze-drying is realized by using radio frequency technology, which can improve the heating efficiency and production efficiency, and reduce the energy consumption.

[0006] In order to achieve the above object, the present application provides the following scheme: the present application provides a radio frequency freeze dryer applied to the production of edible mushroom biscuits, comprising an integrated radio frequency source, a first radio frequency plate, a second radio frequency plate, a vacuum material cavity, a vacuumizing device, a cooling device and a material tray which can be penetrated by a radio frequency electromagnetic field, a copper plate is installed on the first radio frequency plate, the copper plate is connected with the integrated radio frequency source, the second radio frequency plate is grounded, the first radio frequency plate and the second radio frequency plate are spaced apart and arranged in the vacuum material cavity, the vacuumizing device and the cooling device are connected with the vacuum material cavity, and the material tray is arranged between the first radio frequency plate and the second radio frequency plate.

[0007] Preferably, the first radio frequency plate and the second radio frequency plate are spaced apart in an up-down manner, and a plurality of layers of the material tray are arranged between the first radio frequency plate and the second radio frequency plate.

[0008] Preferably, the bottom of the material tray is provided with a positioning pin, the top of the material tray is provided with a positioning hole matched with the positioning pin, and adjacent material trays are connected through the positioning pin and the positioning hole.

[0009] Preferably, a plurality of holes are arranged on the material tray.

[0010] Preferably, one end of the first radio frequency plate away from the second radio frequency plate is connected with a telescopic device through a non-metal component, and the telescopic device drives the first radio frequency plate to move close to or away from the second radio frequency plate.

[0011] Preferably, the integrated radio frequency source, the vacuumizing device, the cooling device and the telescopic device are electrically connected with a control device.

[0012] Preferably, the vacuum material cavity is in a cylindrical shape.

[0013] Preferably, the material tray is made of polytetrafluoroethylene.

[0014] Preferably, the cooling device comprises a compressor, a condenser, a capillary tube and an evaporator which are sequentially connected, the evaporator is connected with the compressor, the evaporator is coiled and arranged on the outer peripheral wall of the shell of the vacuum material cavity, and the shell of the vacuum material cavity is made of a heat-conducting material.

[0015] The present application also provides a freeze drying method applied to the radio frequency freeze dryer applied to the production of edible mushroom biscuits, comprising the following steps:

[0016] S1: placing the material to be freeze-dried on the material tray and placing the material tray between the first radio frequency plate and the second radio frequency plate in the vacuum material cavity;

[0017] S2: start the cooling device to pre-freeze the material to be freeze-dried;

[0018] S3: start the vacuum device to vacuum the vacuum material cavity;

[0019] S4: start the integrated radio frequency source, generate a high-frequency alternating electromagnetic field between the first radio frequency plate and the second radio frequency plate, and complete the sublimation process of the water in the material to be freeze-dried.

[0020] The present application has the following technical effects compared with the prior art:

[0021] The radio frequency is used for freeze-drying the material in the two stages of vacuum sublimation drying and analytical drying. In the freeze-drying process, the water is heated from the inside of the material, so that the water transmission, temperature transmission and humidity transmission are in the same direction. Compared with the ordinary freeze dryer, the heating efficiency can be improved and the energy consumption can be reduced. Moreover, the radio frequency has the characteristics of high penetration, and can realize the processing of the material in the multi-layer stacked material tray, which is beneficial to improve the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 The structure diagram of the radio frequency freeze dryer applied to the edible mushroom biscuit making in the embodiment of the present application;

[0024] Figure 2 The structure diagram of the multi-layer stacked material tray in the embodiment of the present application;

[0025] Figure 3 The structure diagram of the single-layer material tray in the embodiment of the present application;

[0026] Figure 4 The projection importance degree graph of each volatile component variable predicted by the PLS-DA model in the embodiment of the present application;

[0027] 1, integrated radio frequency source; 2, first radio frequency plate; 3, second radio frequency plate; 4, vacuum material cavity; 5, control device; 6, material tray; 61, hole; 62, positioning pin; 63, positioning hole; 7, cooling device. DETAILED DESCRIPTION

[0028] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative efforts belong to the scope of the present application.

[0029] The present application aims to provide a radio frequency freeze dryer and freeze drying method applied to the production of edible mushroom biscuits to solve the problems in the prior art. The radio frequency technology is used to realize freeze drying, which can improve the heating efficiency and production efficiency, and reduce energy consumption.

[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0031] Please refer to the drawings as shown in Figures 1-3 A radio frequency freeze dryer applied to the production of edible mushroom biscuits is provided, which comprises an integrated radio frequency source 1, a first radio frequency electrode plate 2, a second radio frequency electrode plate 3, a vacuum material cavity 4, a vacuum pumping device, a cooling device 7 and a material tray 6 that can be penetrated by a radio frequency electromagnetic field. A copper plate is installed on the first radio frequency electrode plate 2, which is connected with the integrated radio frequency source 1 for transmitting radio frequency. The second radio frequency electrode plate 3 is grounded. The first radio frequency electrode plate 2 and the second radio frequency electrode plate 3 are spaced apart and arranged in the vacuum material cavity 4. The vacuum pumping device and the cooling device 7 are connected with the vacuum material cavity 4 for vacuumizing and cooling the vacuum material cavity 4. The material tray 6 is arranged between the first radio frequency electrode plate 2 and the second radio frequency electrode plate 3. The working principle of the device is as follows: the radio frequency generated by the integrated radio frequency source 1 is transmitted to the first radio frequency electrode plate 2 through the copper plate, and then a high-frequency alternating electromagnetic field is generated between the first radio frequency electrode plate 2 and the second radio frequency electrode plate 3. The polar molecules in the material between the first radio frequency electrode plate 2 and the second radio frequency electrode plate 3 rotate and rub quickly in the alternating electric field, generating heat, thereby completing the sublimation process of the material. In the sublimation process, the material is heated from the inside, so that the water transmission, temperature transmission and humidity transmission are all in the same direction, which can improve the heating efficiency and reduce the energy consumption. Moreover, the radio frequency has the characteristics of high penetration, which can improve the processing capacity of the device and improve the production efficiency.

[0032] The integrated radio frequency source 1 in the embodiment adopts a 6KW integrated radio frequency source, mainly including low-voltage components, high-voltage transformers, 6KW radio frequency tubes, etc. In the later heating process, the radio frequency power is automatically output according to the process requirements. The radio frequency power is steplessly adjusted through the three-phase voltage regulating transformer. One end of the copper plate is connected with the radio frequency tube, and the other end is fixedly connected with the first radio frequency plate 2 through copper bolts. The radio frequency alternating electromagnetic field is emitted through the radio frequency tube and transmitted through the copper sheet. The frequency of the radio frequency is 27.12MHz±0.601%, the selected copper plate is a red copper plate, and the material disc 6 is made of food-grade polytetrafluoroethylene.

[0033] The second radio frequency plate 3 can be welded in the vacuum material cavity 4 to improve its stability.

[0034] The first radio frequency plate 2 and the second radio frequency plate 3 are the same size, 410mm*350mm, and are arranged opposite to each other.

[0035] The specific form of improving the processing capacity is that the first radio frequency plate 2 and the second radio frequency plate 3 are arranged in an upper and lower manner, and a plurality of material discs 6 are arranged between the first radio frequency plate 2 and the second radio frequency plate 3. Through the plurality of material discs 6, the amount of material between the first radio frequency plate 2 and the second radio frequency plate 3 is increased.

[0036] In order to improve the stability of the plurality of material discs 6, a positioning pin 62 is arranged at the bottom of the material disc 6, and a positioning hole 63 matched with the positioning pin 62 is arranged at the top of the material disc 6. Adjacent material discs 6 are inserted through the positioning pin 62 and the positioning hole 63, so as to realize the positioning between adjacent material discs 6.

[0037] In the embodiment, the material disc 6 is selected as a rectangular disc body. A single disc body can hold 0.12m 2 of material. The rectangular disc body is provided with a positioning pin 62 at each of the four corners at the bottom, and four positioning holes 63 are arranged at the top of the peripheral wall in correspondence. Five rectangular disc bodies are arranged in a stack from top to bottom, and the total material laying area can reach 0.6m 2 .

[0038] In an embodiment, a plurality of holes 61 can be arranged on the material disc 6. The plurality of holes 61 are uniformly arranged. The diameter of the hole 61 is 5mm, and the distance between adjacent holes 61 is 10mm. The arrangement of the hole 61 not only reduces the weight of the material disc 6, but also provides a movement path for the water vapor generated in the sublimation process. The size of the hole 61 should be smaller than the size of the material to avoid leakage of the material from the hole 61.

[0039] In an embodiment, the end of the first radio frequency electrode plate 2 away from the second radio frequency electrode plate 3 is connected to the telescopic device through a non-metal component to prevent the leakage of electromagnetic waves caused by the movement of the electromagnetic waves along the rod of the telescopic device. The telescopic device can be a hydraulic telescopic cylinder or an electric telescopic rod, etc. The telescopic device drives the first radio frequency electrode plate 2 to move close to or away from the second radio frequency electrode plate 3, so as to adjust the distance between the first radio frequency electrode plate 2 and the second radio frequency electrode plate 3. In this way, multiple layers of material trays 6 can be placed between the first radio frequency electrode plate 2 and the second radio frequency electrode plate 3 according to the need, and at the same time, the total height of the multiple layers of material trays 6 can be ensured to match the distance between the first radio frequency electrode plate 2 and the second radio frequency electrode plate 3. The range of movement of the first radio frequency electrode plate 2 can be designed to be 0-160mm, and the range of movement of the first radio frequency electrode plate 2 can be designed according to the size of the actual vacuum material cavity 4.

[0040] The integrated radio frequency source 1, the vacuumizing device, the cooling device 7 and the telescopic device are electrically connected to the control device 5. The control device 5 mainly consists of a touch screen, a PLC and other electrical components and a cantilever console. The touch screen is fixed in the cantilever console, and the PLC and other electrical components are mainly fixed on the electrical board and placed in the cantilever console. The control device 5 can intelligently set the parameters of each stage such as the cooling time, the cooling temperature, the distance between the two radio frequency electrode plates, the radio frequency heating time, the radio frequency heating power, the vacuum degree pressure in the vacuum material cavity 4, etc. according to the characteristics and yield of different material substrates. The entire processing process can be completed automatically by one key in the intelligent control device 5.

[0041] The control device 5 is integrated with a remote control module. The function of the mobile phone APP can be used to remotely monitor the equipment through the mobile phone, so as to ensure the product quality, production safety and stability, and optimize the energy consumption in the material processing process.

[0042] In this embodiment, the cavity of the vacuum material cavity 4 is cylindrical. Compared with a square cavity, the cylindrical shape is more convenient for maintaining the vacuum degree. The specific size of the shell of the vacuum material cavity 4 is 500mm in diameter and 800mm in length.

[0043] The cooling device 7 comprises a compressor, a condenser, a capillary tube and an evaporator connected in sequence, the evaporator is connected with the compressor, and the evaporator is coiled on the outer peripheral wall of the shell of the vacuum material cavity 4, that is, the pipeline of the evaporator is coiled to form a structure similar to a cylindrical pipeline and is sleeved on the outer peripheral wall of the shell of the vacuum material cavity 4. The material of the shell of the vacuum material cavity 4 is a heat-conducting material, for example, 304 stainless steel. The cooling principle is as follows: the compressor extracts the gaseous refrigerant from the evaporator and pressurizes it into the condenser. The gaseous refrigerant forms high-pressure and high-temperature gas in the compressor, and the high-pressure gaseous refrigerant is liquefied when passing through the condenser to form low-temperature and high-pressure condensate, and the pressure of the refrigerant is reduced through the capillary tube, so that the refrigerant reenters the evaporator. The evaporator removes the energy inside the vacuum material cavity 4 through the shell of the vacuum material cavity 4. The refrigerant forms gas in the evaporator, and the gaseous refrigerant is extracted by the compressor and pumped into the condenser. In this way, the refrigerant is circulated and flows continuously to continuously cool and refrigerate the cavity.

[0044] The compressor and the like and the vacuum material cavity 4 are arranged in a box, and the box is divided into two cavities by a partition plate, and the vacuum material cavity 4 and the compressor and the like are arranged in the two cavities, respectively.

[0045] A freeze-drying method is characterized in that a radio frequency freeze dryer for making edible mushroom biscuits is applied, and the method comprises the following steps:

[0046] S1: placing the material to be freeze-dried on the material disc 6, and placing the material disc 6 between the first radio frequency plate 2 and the second radio frequency plate 3 in the vacuum material cavity 4;

[0047] S2: starting the cooling device 7 to pre-freeze the material to be freeze-dried;

[0048] S3: starting the vacuumizing device to vacuumize the vacuum material cavity 4;

[0049] S4: starting the integrated radio frequency source 1 to generate a high-frequency alternating electromagnetic field between the first radio frequency plate 2 and the second radio frequency plate 3, and completing the sublimation process of the water in the material to be freeze-dried.

[0050] Please refer to the accompanying Figure 4 The actual production of freeze-dried mushroom powder is analyzed by PLS-DA, R2=0.998, Q2=0.959, and R2 and Q2 are greater than 0.5, indicating that the model has good prediction characteristics. Through 200 times of permutation test, the intersection point of Q2 and the vertical axis in the analysis result is less than 0, indicating that the model is effective and there is no overfitting.

[0051] To further measure the contribution of each variable, the projection importance of variables (VIP) of each volatile component was predicted based on the PLS-DA model, and when VIP was greater than 1, it indicated that the variable had a high contribution to the overall discriminant model. The compounds with VIP>1 were screened as the differential volatile compounds. In the GC-MS results, there were 37 VOCs with VIP>1, including the top 10 volatile compounds with VIP values, including 1-ethanol, 2-heptanone, 3-octen-2-one, 2-butyl-2-octenal, 2-ethylhexanol, benzyl cyanide, 3-methylbutyric acid, 1-octen-3-ol, hexanoic acid, etc.

[0052] Taking the freeze-dried straw mushroom powder produced by the device and the biscuits made therefrom as examples, and comparing the air-dried straw mushroom powder and the biscuits made therefrom, it is concluded from Table 1 below that the freeze-dried straw mushroom powder has five kinds of key flavor substances, the number of which is significantly more than that of the air-dried powder, and contains the main mushroom flavor components, and the flavor reduction degree is higher. The mushroom characteristic substance (1-octen-3-one) is detected in the freeze-dried straw mushroom powder, while such a substance is not detected in the air-dried sample. The mushroom flavor is better preserved in the freeze-dried straw mushroom powder. The freeze-dried straw mushroom biscuits have two kinds of key flavors, namely, nut roasting (methyl pyrazine) and cocoa flavor (butyrolactone) and bitter almond flavor. Among them, methyl pyrazine (nut roasting, ROAV=11.17) and butyrolactone (cocoa flavor, ROAV=100) are detected, and the concentration of the latter reaches the upper limit of the threshold value; although methyl pyrazine (ROAV=43.38) and butyrolactone (ROAV=36.71) are detected in the air-dried biscuits, the ROAV value of phenylacetaldehyde is relatively low, resulting in a decrease in the flavor level. The phenylacetaldehyde (ROAV≥35) preserved by the freeze-drying process provides a bitter almond base tone, and after baking, the bitter almond flavor disappears or is less detected, while the bitter almond flavor of the air-dried straw mushroom powder is higher after baking. Hexanal is a fat oxidation product, and when the concentration is high, it is often described as having a raw taste, a green taste and a bean smell. The detected hexanal in the air-dried straw mushroom powder and biscuits has an ROAV value of 100, while no hexanal is detected in the freeze-dried straw mushroom powder and biscuits, indicating that the freeze-drying process can obtain better flavor.

[0053] Table 1 is the ROAV value of the key volatile flavor substances in the straw mushroom samples

[0054]

[0055] Adaptive changes according to actual needs are within the protection scope of the present application.

[0056] It is to be understood that the application is not limited to the details of the above-exemplified embodiments and that the present application can be carried out in other ways without deviating from the sprit or essential characteristics of the application. Therefore, the embodiments are to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the scope of the claims.

[0057] The above examples are illustrative of the present application and are not intended to limit the scope of the application. Rather, the scope of the present application is to be given by the appended claims together with their full scope of equivalents.

Claims

1. A radio frequency freeze dryer for use in the manufacture of edible mushroom cookies, characterized in that, The application relates to a radio frequency freeze dryer for making edible mushroom biscuits, which comprises an integrated radio frequency source, a first radio frequency plate, a second radio frequency plate, a vacuum material cavity, a vacuumizing device, a cooling device and a material disc which can be penetrated by a radio frequency electromagnetic field, a copper plate is arranged on the first radio frequency plate, the copper plate is connected with the integrated radio frequency source, the second radio frequency plate is arranged in a grounding mode, the first radio frequency plate and the second radio frequency plate are arranged in a spaced mode in the vacuum material cavity, the vacuumizing device and the cooling device are connected with the vacuum material cavity, and the material disc is arranged between the first radio frequency plate and the second radio frequency plate.

2. The radio frequency freeze dryer for use in making edible mushroom cookies according to claim 1, wherein, The first radio frequency plate and the second radio frequency plate are arranged in a spaced mode in an up-down mode, and a plurality of layers of the material disc are arranged in a stacked mode between the first radio frequency plate and the second radio frequency plate.

3. The radio frequency freeze dryer for use in making edible mushroom cookies according to claim 2, wherein, A positioning pin is arranged at the bottom of the material disc, a positioning hole matched with the positioning pin is arranged at the top of the material disc, and adjacent material discs are connected through the positioning pin and the positioning hole.

4. The radio frequency freeze dryer for use in making edible mushroom cookies according to claim 2, wherein, A plurality of holes are arranged on the material disc.

5. The radio frequency freeze dryer for use in making edible mushroom cookies according to claim 1, wherein, One end of the first radio frequency plate away from the second radio frequency plate is connected with a telescopic device through a non-metal component, and the telescopic device drives the first radio frequency plate to move close to or away from the second radio frequency plate.

6. The radio frequency freeze dryer for use in making edible mushroom cookies according to claim 5, wherein, The integrated radio frequency source, the vacuumizing device, the cooling device and the telescopic device are electrically connected with a control device.

7. The radio frequency freeze dryer for use in making edible mushroom cookies according to claim 1, wherein, The vacuum material cavity is in a cylindrical shape.

8. The radio frequency freeze dryer for use in making edible mushroom cookies according to claim 1, wherein, The material disc is made of polytetrafluoroethylene.

9. The radio frequency freeze dryer for use in making edible mushroom cookies according to claim 1, wherein, The cooling device comprises a compressor, a condenser, a capillary tube and an evaporator which are sequentially connected, the evaporator is connected with the compressor, the evaporator is arranged in a coiled mode on the outer peripheral wall of the shell of the vacuum material cavity, and the shell of the vacuum material cavity is made of a heat-conducting material.

10. A lyophilization method characterized by, The application of the radio frequency freeze dryer for making edible mushroom biscuits according to any one of claims 1-9 comprises the following steps: S1: placing the material to be freeze-dried on the material disc and placing the material disc between the first radio frequency plate and the second radio frequency plate in the vacuum material cavity; S2: starting the cooling device to pre-freeze the material to be freeze-dried; S3: starting the vacuumizing device to vacuumize the vacuum material cavity; S4: starting the integrated radio frequency source, generating a high-frequency alternating electromagnetic field between the first radio frequency plate and the second radio frequency plate, and completing the sublimation process of the water in the material to be freeze-dried.

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