Quality-energy consumption collaborative optimization apple slice radio frequency vacuum drying intelligent regulation and control strategy
By employing a radio frequency vacuum drying strategy that involves phased adjustment of drying parameters and real-time monitoring, the problems of quality deterioration and energy waste during the drying process of apple slices have been solved, achieving a high-efficiency and low-consumption drying effect.
Patent Information
- Application Number
- CN202511512487.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-22
- Publication Date
- 2026-01-06
AI Technical Summary
Existing radio frequency vacuum drying technology lacks real-time response and control during the drying process of apple slices, resulting in deterioration of apple slice quality and waste of energy in the later stages of drying.
A radio frequency vacuum drying strategy with phased adjustment of drying parameters is adopted, including rapid dehydration at high temperature and low vacuum in the early stage and slow dehydration at low temperature and high vacuum in the later stage. The drying process is optimized by combining fiber optic temperature sensors and weight sensors for real-time monitoring.
This method achieves efficient and low-consumption drying of apple slices, improves the quality of dried apple slices, and reduces nutrient loss and energy consumption.
Smart Images
Figure CN121264518A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fruit and vegetable drying and processing technology. Background Technology
[0002] Apples are rich in vitamins and minerals, making them highly valuable. However, fresh apples have a high water content (approximately 85%), making them highly susceptible to spoilage during harvesting, transportation, and storage. Drying apples can effectively extend their shelf life and improve their economic benefits. Furthermore, appropriate drying processes can improve the texture of apple slices, resulting in greater crispness and a sweeter, more tart flavor. Radiofrequency vacuum drying technology is widely used in fruit and vegetable drying due to its rapid heating mode (volume heating), low energy consumption, and minimal damage to the material structure. However, current radiofrequency vacuum drying methods often use fixed parameters, lacking real-time response and control over the material's state. This leads to significant deterioration in the quality of apple slices in the later stages of drying, resulting in uneven moisture distribution, localized overheating, nutrient loss, and structural collapse. Summary of the Invention
[0003] Purpose of the invention: The present invention aims to solve the above problems and provide a radio frequency vacuum drying strategy that adjusts the equipment process parameters according to the dehydration energy requirements during the drying process of apple slices, so as to achieve efficient, low-consumption, and high-quality drying effect.
[0004] Technical Solution: To achieve the above objectives, the present invention provides a quality-energy consumption synergistic optimization intelligent control strategy for radio frequency vacuum drying of apple slices, comprising the following steps:
[0005] S1. Peel the fresh apple with a peeler, and cut the peeled apple sample into thin slices with a thickness of 6.5±0.2mm using a slicer. Then, remove the core using a metal mold to obtain apple slices with an outer diameter of 70±2mm and an inner diameter of 25.0±0.1mm.
[0006] S2. Arrange 12 apple samples (total mass 205.5±2.3g) evenly in a rectangular tray, with a center-to-center distance of 10mm between adjacent samples. The tray dimensions are 400mm (length) × 260mm (width) × 35mm (height). Figure 1 This is a schematic diagram showing the arrangement of the samples;
[0007] S3. Place the tray in the center of the lower electrode plate of the drying chamber of the radio frequency vacuum drying equipment. Insert three fiber optic temperature sensors into the apple slices in the corners, edges and center of the tray. The probes are inserted to a depth of 11mm and kept parallel to the radial direction of the apple slices.
[0008] S4. Dry the apple slices at a drying temperature of 65-68℃, a vacuum degree of 0.023-0.025MPa, and an electrode spacing of 70-73mm. Observe the front panel of the radio frequency vacuum drying equipment. Stop drying when the moisture content of the apple slices reaches 40-42.5% and turn off the power.
[0009] S5. Based on S4, remove the tray and allow it to cool gently at room temperature for 5-7 minutes until the surface temperature of the apple slice sample returns to 24.5-26.5℃.
[0010] S6. Based on S5, adjust the drying temperature to 55-60℃, the vacuum degree to 0.025-0.030MPa, and the electrode spacing to 75-78mm to perform secondary radio frequency vacuum drying on the apple slices. The drying process ends when the moisture content of the apple slices reaches 14-15%.
[0011] S7. Based on S6, take out the dried apple slices, let them thaw at room temperature for 5-7 minutes, and then put them into a plastic bag for sealed storage.
[0012] Furthermore, the moisture content of S1 fresh apple slices is 84.5-85%.
[0013] Furthermore, the S2's tray is made of polypropylene, and the container's side and bottom walls have 10mm diameter holes, which facilitates moisture migration.
[0014] Furthermore, the S3's radio frequency vacuum equipment has an output power of 3kW and a frequency of 27.12MHz. The equipment can monitor the temperature changes of the sample in real time through a fiber optic temperature measurement system; and it can monitor the changes in the moisture content of the sample through a built-in weight sensor.
[0015] Furthermore, the drying time for S4 apple slices with a moisture content of 40-42.5% is approximately 1.0-1.3 hours.
[0016] Furthermore, the drying time for S6 apple slices to reach a moisture content of 14-15% is approximately 1.2-1.5 hours.
[0017] Beneficial Effects: The radio frequency vacuum drying mode of this invention utilizes the powerful moisture-driving force provided by the synergistic effect of radio frequency volume heating and the negative pressure environment of a vacuum to achieve rapid, low-temperature dehydration of apple slices. This effectively reduces the loss of nutritional quality. Furthermore, by setting drying parameters in stages according to the dehydration requirements of different drying stages of the apple slices, the quality of the dried apple slices is improved, and equipment energy consumption is effectively reduced. Details are as follows:
[0018] 1. Improving Apple Slice Quality: During the first stage of drying, the apple slices have a high free water content, and the evaporation and heat absorption effectively prevent the material itself from overheating. Therefore, the first stage of radio frequency vacuum drying uses a higher drying temperature, a lower vacuum degree, and a smaller electrode spacing to quickly remove moisture and reduce browning of the apple slices during the drying process. During the second stage of drying, the moisture content of the apple slices decreases. To prevent localized overheating and quality deterioration, the process parameters of the equipment are adjusted to lower the drying temperature, increase the vacuum degree, and increase the electrode spacing, allowing the apple slices to undergo slow dehydration in a low-temperature environment, effectively improving quality.
[0019] 2. Reduced Drying Energy Consumption: Traditional drying methods use fixed parameters, resulting in energy supply exceeding the material's dehydration needs in the later stages of drying, leading to quality deterioration and energy loss. In the second drying stage of this invention, the process parameters are adjusted to slow down the dehydration rate of the apple slices, providing energy only as needed, effectively reducing drying energy consumption.
[0020] 3. After the first stage of radio frequency vacuum drying, remove the apple slices and allow them to rest at room temperature. This helps to balance the moisture distribution inside the apple slices and prevents localized overheating during subsequent drying. It also lowers the temperature of the apple slices to prevent excessively high temperatures during the subsequent drying process from reducing nutrient content. Attached Figure Description
[0021] Figure 1 This is a flowchart of the intelligent control process for radio frequency vacuum drying of apple slices;
[0022] Figure 2 This is a framework diagram for intelligent control of quality and energy consumption synergy optimization;
[0023] Figure 3 This is a diagram showing apple slice samples arranged on a tray.
[0024] Attached image descriptions: 1: Tray; 2: Apple slices. Detailed Implementation
[0025] The following specific implementation examples further illustrate the intelligent control strategy for RF vacuum drying of apple slices based on the quality-energy consumption synergistic optimization of this invention. However, this invention is not limited to these examples, such as... Figures 1-3 The intelligent control strategy for RF vacuum drying of apple slices, which optimizes both quality and energy consumption, is implemented as follows:
[0026] Example 1
[0027] S1. Peel the fresh apple with a peeler, and cut the peeled apple sample into thin slices with a thickness of 6.5±0.2mm using a slicer. Then, remove the core using a metal mold to obtain apple slices with an outer diameter of 70±2mm and an inner diameter of 25.0±0.1mm.
[0028] S2. Spread 12 apple samples (total mass 205.5±2.3g) evenly in a rectangular tray, with the center distance between adjacent samples being 10mm. The tray dimensions are 400mm (length) × 260mm (width) × 35mm (height).
[0029] S3. Place the tray in the center of the lower electrode plate of the drying chamber of the radio frequency vacuum drying equipment. Insert three fiber optic temperature sensors into the apple slices in the corners, edges and center of the tray. The probes are inserted to a depth of 11mm and kept parallel to the radial direction of the apple slices.
[0030] S4. Dry the apple slices at a drying temperature of 65℃, a vacuum degree of 0.023MPa, and an electrode spacing of 70mm. Observe the front panel of the radio frequency vacuum drying equipment. Stop drying when the moisture content of the apple slices reaches 42% and turn off the power.
[0031] S5. Based on S4, remove the tray and allow it to rest at room temperature for 6 minutes until the surface temperature of the apple slice sample returns to 25°C.
[0032] S6. Based on S5, adjust the drying temperature to 55℃, the vacuum degree to 0.025MPa, and the electrode spacing to 75mm to perform secondary radio frequency vacuum drying on the apple slices. The drying process ends when the moisture content of the apple slices reaches 14.5%.
[0033] S7. Based on S6, take out the dried apple slices, let them thaw at room temperature for 6 minutes, and then put them into a plastic bag for sealed storage.
[0034] Example 2
[0035] A method similar to Example 1, except that in "S4", the drying temperature of the first stage of radio frequency vacuum drying is reduced to 60°C and the vacuum degree is increased to 0.03MPa.
[0036] Example 3
[0037] A method similar to Example 1, except that in "S4", the drying temperature of the first stage of radio frequency vacuum drying is increased to 70°C and the vacuum degree is reduced to 0.02MPa.
[0038] Comparative Example
[0039] Fresh apple slices with an outer diameter of 70±2 mm and an inner diameter of 25.0±0.1 mm were prepared according to “S1” of Example 1.
[0040] Test case
[0041] The soluble solids content, color, and energy consumption of the apple slices prepared in Examples 1-3 and the comparative examples were determined.
[0042] Determination of soluble solids content: Take 5.0g of apple slices, grind them in a mortar, centrifuge, take the supernatant, and measure the soluble solids content in the apple slices using a digital refractometer. The result is expressed as °Bx.
[0043] Color measurement: Direct measurement is performed using a colorimeter. The colorimeter is calibrated using a standard white plate provided with it before measurement. Color gradations are described based on the L*, a*, and b* values of the CIELab color space. Specifically, L* represents lightness or darkness, ranging from 0 (black) to 100 (white), a* represents red (+) and green (-), and b* represents yellow (+) and blue (-).
[0044] Energy consumption measurement: The radio frequency vacuum equipment is equipped with an energy meter to measure the energy consumption (kWh) of the drying process.
[0045] The results are shown in Tables 1 and 2.
[0046] Table 1 Comparison of soluble solids content
[0047] index Example 1 Example 2 Example 3 Soluble solids content, °Bx 13.08 13.58 12.27
[0048] Table 2. Color Comparison Results
[0049] index Example 1 Example 2 Example 3 Comparative Example L* 56.52 56.85 55.26 57.75 a* 1.08 -0.18 1.53 -0.63 b* 28.75 26.87 29.33 24.56
[0050] Table 3 Energy Consumption Comparison Results
[0051] index Example 1 Example 2 Example 3 Energy consumption, kWh 10.5 12.8 9.8 Time consumed, h 2.5 3.2 2
[0052] Table 1 shows that radio frequency vacuum drying of apple slices at 60-65℃ maintains a high soluble solids content. However, when the drying temperature reaches 70℃ (Example 3), the higher temperature has an adverse effect on the soluble solids content. Table 2 shows that compared with fresh apple slices (comparative example), the L* of the apple slices dried by radio frequency vacuum drying (Examples 1, 2, and 3) is lower, while a* and b* are higher. Furthermore, the higher the drying temperature in the first stage, the more obvious the change in appearance color. Table 3 shows that Example 1 saves approximately 18.0% in energy consumption and 21.9% in time compared to Example 2, and the quality of the dried apple slices does not deteriorate significantly. While Example 3 saves approximately 6.7% in energy consumption compared to Example 1, the excessively high drying temperature (70℃) in the first drying stage leads to a 6.2% decrease in soluble solids content compared to Example 1, and a deeper browning of the appearance color (increased b*), which does not meet consumer preferences. Considering both energy consumption and product quality, the process level selected in Example 1 is more suitable.
[0053] In summary, the intelligent control strategy for radio frequency vacuum drying of apple slices with quality-energy consumption synergistic optimization of the present invention can effectively improve the quality of dried apple slices and reduce drying energy consumption.
[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A smart control strategy for RF vacuum drying of apple slices with quality-energy consumption synergistic optimization, characterized in that, Includes the following steps: S1. Peel and slice fresh apples to make apple slices with a thickness of 6.5±0.2mm. Then remove the cores to obtain apple slices with an outer diameter of 70±2mm and an inner diameter of 25.0±0.1mm. S2. Arrange the 12 apple slices evenly in a tray with a center-to-center distance of 10mm. The tray has dimensions of 400mm×260mm×35mm. S3. Place the tray at the center of the lower electrode plate of the radio frequency vacuum drying equipment, and insert three optical fiber temperature sensors into the apple slices in the corners, edges and center of the tray. The probes are inserted to a depth of 11mm and are parallel to the radial direction of the apple slices. S4. The first stage of drying is carried out under the conditions of drying temperature 65–68℃, vacuum degree 0.023–0.025MPa, and electrode spacing 70–73mm, and is stopped when the moisture content of apple slices is 40–42.5%. S5. Let the apple slices rest at room temperature for 5–7 minutes, until the surface temperature returns to 24.5–26.5℃; S6. Adjust the drying temperature to 55–60℃, the vacuum degree to 0.025–0.030MPa, and the electrode spacing to 75–78mm, and carry out the second stage of drying until the moisture content of the apple slices is 14–15%. S7. After drying, let the apple slices thaw at room temperature for 5–7 minutes, then seal and store.
2. The intelligent control strategy for quality-energy consumption synergistic optimization of apple slice radio frequency vacuum drying according to claim 1, characterized in that, The moisture content of the fresh apple slices in S1 is 84.5–85%.
3. The intelligent control strategy for quality-energy consumption synergistic optimization of apple slice radio frequency vacuum drying according to claim 1, characterized in that, The tray in S2 is made of polypropylene, and its side walls and bottom walls are provided with round holes with a diameter of 10mm.
4. The intelligent control strategy for quality-energy consumption synergistic optimization of apple slice radio frequency vacuum drying according to claim 1, characterized in that, The S3 radio frequency vacuum drying equipment has an output power of 3kW and a frequency of 27.12MHz. It is equipped with a fiber optic temperature measurement system and a built-in weight sensor for real-time monitoring of temperature and moisture content.
5. The intelligent control strategy for quality-energy consumption synergistic optimization of apple slice radio frequency vacuum drying according to claim 1, characterized in that, The drying time for the first stage in S4 is approximately 1.0–1.3 h.
6. The intelligent control strategy for quality-energy consumption synergistic optimization of apple slice radio frequency vacuum drying according to claim 1, characterized in that, The second drying time in S6 is approximately 1.2–1.5 h.