Internal circulation type energy-saving heat pump fruit drying equipment

Abstract

The invention relates to the technical field of fruit drying, and discloses internal circulation type energy-saving heat pump fruit drying equipment which comprises a drying box body, a heat pump assembly is fixedly connected to the side face, away from a sealing cover door, of the drying box body, an exhaust port is formed in the side face in the drying box body, and an air return port is formed in the top end in the sealing cover door. An output mechanism is movably connected to the bottom end of the interior of the drying box body, a drainage mechanism is movably connected to the top end of the output mechanism, and a collecting mechanism is fixedly connected to the bottom end of the inner side of the drying box body; when the output shaft rotates, the spiral plate is driven to rotate, when the lowermost portion of the top end of the spiral plate rotates to the position below the connecting plate, along with continuous rotation of the spiral plate, the connecting plate moves downwards along with rotation of the spiral plate and compresses the supporting spring, and when the top end of the spiral plate is separated from the position below the connecting plate, the supporting spring is compressed. And the supporting spring resets, so that the connecting plate drives the placing grid to quickly move downwards, and water in the fruits on the placing grid is thrown out.

Description

Technical Field

[0001] The present invention relates to the technical field of fruit drying, and more particularly to an internal circulation energy-saving heat pump fruit drying device. Background Art

[0002] Fruit drying is an important processing method to extend the shelf life of agricultural products and increase added value. Traditional fruit drying technologies mainly include natural drying and hot air drying. Natural drying depends on climatic conditions and has problems such as difficult hygiene control and susceptibility to contamination and mildew. Although conventional hot air drying can achieve continuous production, it has high energy consumption and low temperature control accuracy, which can easily lead to loss of fruit nutrients, browning and surface hardening. High-temperature drying can easily destroy vitamins and active substances, affecting product quality and market value.

[0003] Heat pump drying technology has significant energy-saving advantages. It recovers dehumidification waste heat through the reverse Carnot cycle principle and can still operate stably in low-temperature environments. When the heat pump dryer is working, it uses heat pump technology to convert low-temperature heat in the air into high-temperature heat. By allowing the air to continuously complete the thermal cycle of evaporation → compression → condensation → throttling → re-evaporation, the heat in the external low-temperature environment is transferred to the drying room. The refrigerant circulates in the system under the action of the compressor, thereby achieving the drying process of the fruit.

[0004] Nowadays, when drying fruits using heat pumps, fruits are usually sliced and placed on the grid in the drying chamber. The fruits are dried through continuous air evaporation. However, the fruits contain a lot of water, so it is difficult to dry the fruits quickly. In particular, it takes a long time to dry out the water inside the fruits. Therefore, the traditional fixed fruit drying process is slow.

[0005] When fruits are dried by slicing, the moisture and juice in the fruit will drip downwards, so moisture will accumulate at the bottom of the drying box. This will cause the humidity inside the drying box to be high, thereby reducing the drying efficiency. In addition, current drying devices cannot intelligently adjust the drying efficiency according to the temperature and humidity inside the drying box. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides an internal circulation energy-saving heat pump fruit drying device to solve the technical problems raised in the background technology.

[0007] To achieve the above-mentioned object, the present invention provides the following technical solution: an internal circulation energy-saving heat pump fruit drying device, comprising a drying box, a sealing cover door movably connected to the side of the drying box, a heat pump assembly fixedly connected to the side of the drying box away from the sealing cover door, an exhaust port opened on the side of the interior of the drying box, and an air return port opened on the top of the interior of the sealing cover door, an output mechanism movably connected to the bottom end of the interior of the drying box, a drainage mechanism movably connected to the top end of the output mechanism, a collection mechanism fixedly connected to the bottom end of the interior of the drying box, and a placement grid fixedly connected to the side of the drainage mechanism;

[0008] The drainage mechanism includes a fixed spiral plate that rotates synchronously with the output mechanism, a connecting plate is provided on the side of the spiral plate, the bottom end of the connecting plate is in contact with the upper surface of the spiral plate, the top end of the connecting plate is fixedly connected to a limiting rod, the side of the limiting rod is movably connected to a fixed plate, the side of the fixed plate is fixedly connected to the interior of the drying box, the side of the limiting rod is provided with a support spring, and the support spring is located between the connecting plate and the fixed plate.

[0009] Furthermore, the heat pump assembly is in communication with the interior of the drying box through the exhaust port and the return air port, and the sealing cover door is fixedly connected to the side of the drying box close to the intelligent collector. When the placement grid moves, the placement grid does not contact the intelligent collector.

[0010] Furthermore, the bottom end of the connecting plate close to the side of the spiral plate is provided with an inclined surface, the bottom end of the upper surface of the spiral plate contacts the inclined surface of the side of the connecting plate, and the spiral plate surrounds the side of the output shaft in the output mechanism for half a circle.

[0011] Furthermore, the bottom end of the connecting plate is fixedly connected to a connecting rod, the bottom end of the spiral plate is fixedly connected to a sealing block, the side of the sealing block is movably connected to a gas cavity, and the side of the gas cavity is fixedly connected to the interior of the drying box.

[0012] Furthermore, the bottom end of the gas cavity is provided with an inclined surface, and the bottom end of the gas cavity and the location of the inclined surface are provided with gas holes. The bottom end of the sealing block is adapted to the bottom end inside the gas cavity, and the sealing block seals the inside of the gas cavity.

[0013] Furthermore, the output mechanism includes a controllable servo motor, the top of the servo motor is fixedly connected to an output shaft, the bottom end of the side of the output shaft is fixedly connected to an output bevel gear, the side of the output bevel gear is meshed with a connecting gear rod, the side of the connecting gear rod away from the output bevel gear is meshed with a synchronous bevel gear, the interior of the synchronous bevel gear is fixedly connected to a synchronous shaft, and the top of the output shaft and the side of the synchronous shaft are both fixedly connected to the inside of the spiral plate.

[0014] Furthermore, an output shaft and a synchronous shaft are provided on both sides of the placement grid, and the output shaft, the synchronous shaft and the spiral plates at the top of the two are mirror-symmetrical. The bottom end of the side of the output shaft is fixedly connected with a synchronous belt, which connects the output shafts on both sides, and the synchronous belt enables the output shafts on both sides of the placement grid to rotate synchronously.

[0015] Furthermore, the collecting mechanism includes discharge inclined plates located on both sides of the bottom end inside the drying box body, and the height of the two discharge inclined plates increases from the sides close to each other to the sides away from each other, and a discharge channel is opened in the sides close to each other of the two discharge inclined plates, and the height of the discharge channel away from the sealing cover door is lower than the height of the side close to the sealing cover door.

[0016] Furthermore, a collecting cylinder is provided at the bottom end of the discharge channel away from the side of the sealing cover door, and the collecting cylinder is communicated with the discharge channel. A discharge pipe is fixedly connected to the bottom end of the collecting cylinder, and an electric control valve is fixedly connected to the side of the discharge pipe. The electric control valve is located outside the drying box away from the side of the collecting cylinder.

[0017] Technical effects and advantages of the present invention:

[0018] 1. When the output shaft of the present invention rotates, it drives the spiral plate to rotate. When the bottom of the top of the spiral plate rotates to the bottom of the connecting plate, as the spiral plate continues to rotate, the connecting plate moves downward with the rotation of the spiral plate and compresses the support spring. When the top of the spiral plate is separated from the bottom of the connecting plate, the support spring resets, causing the connecting plate to drive the placement grid to move downward rapidly, thereby throwing out the moisture in the fruit placed on the grid;

[0019] 2. When the connecting plate of the present invention moves downward, it drives the connecting rod to move downward, and when the connecting rod moves downward, it drives the sealing block to move downward. When the sealing block moves downward, it moves in the gas cavity, thereby blowing the gas in the gas cavity out through the bottom of the gas cavity and blowing it onto the next layer of placement grid and collection mechanism. When blowing onto the placement grid, it is convenient to blow away the horizontal moisture. When blowing onto the collection mechanism, it is convenient for the moisture to flow into the collection cylinder in the collection mechanism and then be collected by the collection cylinder.

[0020] 3. The present invention is provided with a discharge inclined plate, a discharge channel and a collecting cylinder. When moisture flows from the surface of the fruit and the placement grid to the top of the collecting mechanism, it first flows to the top of the discharge inclined plate, flows into the discharge channel through the inclined surface of the discharge inclined plate, and then flows into the collecting cylinder through the inclined surface of the discharge channel. It is collected by the collecting cylinder, thereby reducing the emission of moisture into the drying box, reducing the humidity in the drying box, and improving the drying effect of the fruit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the internal structure of the drying box of the present invention.

[0023] Figure 3 This is a schematic structural diagram of the output mechanism of the present invention within the drying box.

[0024] Figure 4 It is a schematic diagram of the decomposed structure of the output mechanism of the present invention.

[0025] Figure 5 It is a schematic diagram of the overall structure of the drainage mechanism of the present invention.

[0026] Figure 6 It is a bottom view schematic diagram of the drainage mechanism of the present invention.

[0027] Figure 7 Schematic diagram of the internal structure of the gas chamber of the present invention.

[0028] Figure 8 It is a schematic structural diagram of the collection mechanism of the present invention.

[0029] Figure 9 Schematic diagram of color difference of mango slices obtained by different drying methods of the present invention.

[0030] Figure 10 Schematic diagram of the antioxidant capacity of dried mangoes under different drying methods of the present invention.

[0031] Figure 11 Schematic diagram of the electronic nose radar diagram of mango slices under different drying methods of the present invention.

[0032] Figure 12 Schematic diagram showing the comparative differences in volatile substance composition of mango slices under different drying methods of the present invention.

[0033] Figure 13 Schematic diagram of the fingerprint of mango slices under different drying methods of the present invention.

[0034] The accompanying drawings are marked as follows: 1. Drying box; 2. Sealing cover door; 3. Heat pump assembly; 4. Exhaust port; 5. Return air port; 6. Output mechanism; 601. Servo motor; 602. Output shaft; 603. Output bevel gear; 604. Connecting gear rod; 605. Synchronous bevel gear; 606. Synchronous shaft; 607. Synchronous belt; 7. Collecting mechanism; 701. Unloading inclined plate; 702. Unloading channel; 703. Collecting cylinder; 704. Discharge pipe; 705. Electric control valve; 8. Drainage mechanism; 801. Spiral plate; 802. Connecting plate; 803. Limiting rod; 804. Fixed plate; 805. Support spring; 806. Gas chamber; 807. Connecting rod; 808. Sealing block; 9. Placement grid; 10. Intelligent collector. DETAILED DESCRIPTION

[0035] The technical solutions of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. In addition, the various structural forms described in the following embodiments are merely illustrative. The internal circulation energy-saving heat pump fruit drying equipment involved in the present invention is not limited to the various structures described in the following embodiments. All other embodiments obtained by ordinary technicians in this field without making creative work fall within the scope of protection of the present invention.

[0036] Example 1

[0037] Reference Figure 1 、 Figure 2 as well as Figure 3 The present invention provides an internal circulation energy-saving heat pump fruit drying equipment, comprising a drying box 1, a sealed cover door 2 movably connected to the side of the drying box 1, a heat pump assembly 3 fixedly connected to the side of the drying box 1 away from the sealed cover door 2, an exhaust port 4 is provided on the side inside the drying box 1, and an air return port 5 is provided on the top inside the sealed cover door 2, an output mechanism 6 is movably connected to the bottom end of the inside of the drying box 1, a drainage mechanism 8 is movably connected to the top end of the output mechanism 6, a collecting mechanism 7 is fixedly connected to the bottom end of the inside of the drying box 1, a placement grid 9 is fixedly connected to the side of the drainage mechanism 8, the heat pump assembly 3 is circulated with the interior of the drying box 1 through the exhaust port 4 and the air return port 5, an intelligent collector 10 is fixedly connected to the side of the sealed cover door 2 close to the drying box 1, and when the placement grid 9 moves, the placement grid 9 does not contact the intelligent collector 10.

[0038] In the embodiment of the present application, the temperature and humidity inside the drying box 1 can be detected by the intelligent collector 10. When the humidity inside the drying box 1 is high, the working power of the heat pump component 3 is guaranteed, thereby increasing the drying effect. The output mechanism 6 of the present application is located below the drying space inside the drying box 1, and when the output mechanism 6 is installed in a avoided position inside the drying box 1, the space where the output mechanism 6 is avoided will not contact the collection cylinder 703 in the collection mechanism 7, thereby avoiding interference between the two.

[0039] Reference Figure 4The output mechanism 6 includes a controllable servo motor 601, the top of the servo motor 601 is fixedly connected to the output shaft 602, the bottom end of the side of the output shaft 602 is fixedly connected to the output bevel gear 603, the side of the output bevel gear 603 is meshed with a connecting gear rod 604, and the side of the connecting gear rod 604 away from the output bevel gear 603 is meshed with a synchronous bevel gear 605, and the interior of the synchronous bevel gear 605 is fixedly connected with a synchronous shaft 606, and the top ends of the sides of the output shaft 602 and the synchronous shaft 606 are fixedly connected to the interior of the spiral plate 801. Output shafts 602 and synchronous shafts 606 are provided on both sides of the placement grid 9, and the output shaft 602, the synchronous shaft 606 and the spiral plates 801 at the tops of the two are mirror-symmetrical, and the bottom end of the side of the output shaft 602 is fixedly connected to a synchronous belt 607, which connects the output shafts 602 on both sides, and the synchronous belt 607 makes the output shafts 602 on both sides of the placement grid 9 rotate synchronously.

[0040] In the embodiment of the present application, when the servo motor 601 drives the output shaft 602 to output, the output shaft 602 rotates in a mirror-image manner with the synchronous shaft 606 through the connecting gear rod 604, and the spiral plates 801 at the top of the output shaft 602 and the synchronous shaft 606 are mirror-symmetrical, so that when the spiral plate 801 rotates, it will synchronously drive the placement grid 9 to move upward, and the synchronous belt 607 connects the output shaft 602 and the synchronous shaft 606 on both sides, so that when the drainage mechanism 8 drives the placement grid 9 to move, the four corners of the placement grid 9 are provided with spiral plates 801 to drive the work, thereby ensuring the stability of the overall work.

[0041] Reference Figure 5 、 Figure 6 as well as Figure 7The drainage mechanism 8 includes a fixed spiral plate 801 that rotates synchronously with the output mechanism 6. A connecting plate 802 is provided on the side of the spiral plate 801. The bottom end of the connecting plate 802 contacts the upper surface of the spiral plate 801. The top of the connecting plate 802 is fixedly connected to the limiting rod 803. The side of the limiting rod 803 is movably connected to the fixed plate 804. The side of the fixed plate 804 is fixedly connected to the inside of the drying box 1. A supporting spring 805 is provided on the side of the limiting rod 803. The supporting spring 805 is located between the connecting plate 802 and the fixed plate 804. The bottom end of the connecting plate 802 close to the side of the spiral plate 801 is provided with an inclined surface. The bottom of the upper surface of the spiral plate 801 The end contacts the inclined surface of the side of the connecting plate 802, the spiral plate 801 surrounds the side of the output shaft 602 in the output mechanism 6 for half a circle, the bottom end of the connecting plate 802 is fixedly connected to the connecting rod 807, the bottom end of the spiral plate 801 is fixedly connected to the sealing block 808, the side of the sealing block 808 is movably connected to the gas cavity 806, the side of the gas cavity 806 is fixedly connected to the interior of the drying box 1, the bottom end of the gas cavity 806 is provided with an inclined surface, and the bottom end of the gas cavity 806 and the location of its inclined surface are provided with gas holes, the bottom end of the sealing block 808 is adapted to the bottom end of the inside of the gas cavity 806, and the sealing block 808 seals the inside of the gas cavity 806.

[0042] In the embodiment of the present application, an inclined surface is provided at the bottom end of the side surface of the connecting plate 802, and the bottom end of the upper surface of the spiral plate 801 contacts the inclined surface of the side surface of the connecting plate 802, so that the spiral plate 801 and the connecting plate 802 are more stable when in contact, and the spiral plate 801 surrounds the side surface of the output shaft 602 in the output mechanism 6 by half a circle. Therefore, when the output shaft 602 rotates half a circle, the connecting plate 802 will continue to rise. When it rotates another half circle, the connecting plate 802 will separate from the spiral plate 801 and move under the drive of the support spring 805. After the connecting plate 802 moves downward, it drives the sealing block 808 to move in the gas chamber 806. When the gas in the gas chamber 806 is blown out, it will be buffered to prevent the connecting plate 802 from falling too fast and causing damage to the components. Gas holes are provided at the bottom end of the gas chamber 806 and at the location of its inclined surface, so that the gas can be blown out downward and obliquely downward. Figure 6 As shown, the grid 9 and the collecting mechanism 7 placed below are blown with gas more evenly. The sealing block 808 seals the interior of the gas cavity 806 to ensure that the gas can be blown out through the gas hole below the gas cavity 806. The bottom end of the sealing block 808 is adapted to the bottom end of the inside of the gas cavity 806, and can blow out the gas in the gas cavity 806 to the greatest extent.

[0043] Reference Figure 1 、 Figure 2 and Figure 8The collecting mechanism 7 includes a discharge inclined plate 701 located on both sides of the bottom end of the drying box body 1. The height of the two discharge inclined plates 701 increases from the sides close to each other to the sides away from each other, and a discharge channel 702 is provided in the sides close to each other of the two discharge inclined plates 701. The height of the side of the discharge channel 702 away from the sealing cover door 2 is lower than the height of the side close to the sealing cover door 2. A collecting cylinder 703 is provided at the bottom end of the side of the discharge channel 702 away from the sealing cover door 2. The collecting cylinder 703 is communicated with the discharge channel 702. The bottom end of the collecting cylinder 703 is fixedly connected to a discharge pipe 704. The side of the discharge pipe 704 is fixedly connected to an electric control valve 705. The side of the electric control valve 705 away from the collecting cylinder 703 is located outside the drying box body 1.

[0044] In the embodiment of the present application, moisture will flow into the discharge channel 702 through the inclined surface above the discharge inclined plate 701. The discharge channel 702 itself is also inclined, so it will flow into the collecting cylinder 703 through the discharge channel 702 and be collected by the collecting cylinder 703. The channel area above the collecting cylinder 703 connected to the discharge channel 702 is small, which prevents a large amount of moisture in the collecting cylinder 703 from entering the drying box 1, ensuring that the humidity in the drying box 1 is low, and the moisture in the collecting cylinder 703 can flow out from the discharge pipe 704 by opening the electric control valve 705 and be collected. The electric control valve 705 can seal the discharge pipe 704 to prevent it from contacting the outside world during drying and causing leakage.

[0045] The working principle of the present invention is as follows: the fruit to be dried is placed on the placement grid 9, the sealing cover door 2 is closed, and the heat pump component 3 is started. After the heat pump component 3 is started, the exhaust is exhausted through the exhaust port 4 and the air is returned to the heat pump component 3 through the return port 5 to perform heat pump drying.

[0046] When the heat pump assembly 3 is working, the servo motor 601 is started, and the servo motor 601 drives the output shaft 602 to rotate when it is started. When the output shaft 602 rotates, it drives the output bevel gear 603 to rotate. When the output bevel gear 603 rotates, it drives the synchronous bevel gear 605 to rotate through the connecting gear rod 604. When the synchronous bevel gear 605 rotates, it drives the synchronous shaft 606 inside it to rotate. When the output shaft 602 rotates, it drives the synchronous belt 607 to rotate, thereby making the output shaft 602 and the synchronous shaft 606 on the other side rotate synchronously with the output shaft 602 and the output bevel gear 603 on the side where the servo motor 601 is located. At this time, the output shaft 602 and the synchronous shaft 606 rotate in a mirror image, while the output shaft 602 and the synchronous shaft 606 on the other side rotate synchronously;

[0047] When the connecting plate 802 moves downward, the placing grid 9 is driven downward by the connecting plate 802, so that the water on the fruit can be thrown out.

[0048] When the connecting plate 802 moves downward, the sealing block 808 is driven downward by the connecting rod 807. When the connecting rod 807 moves downward, the gas inside the gas cavity 806 is pushed out from below. When the gas in the gas cavity 806 is pushed out, it blows above the placement grid 9 to blow away the moisture on the horizontal surface of the placement grid 9. When it blows above the collecting mechanism 7, it facilitates the flow of moisture on the collecting mechanism 7. When the connecting plate 802 drives the sealing block 808 to move to the lowest point inside the gas cavity 806, the lowest point of the top of the spiral plate 801 contacts the bottom end of the connecting plate 802 again, causing the connecting plate 802 to move upward again. When the connecting plate 802 drives the sealing block 808 to move upward, the gas enters the gas cavity 806 through the gas hole below the gas cavity 806.

[0049] When the water flows out of the fruit, it will flow through the fruit and the placement grid 9 into the discharge inclined plate 701, and flow into the discharge channel 702 through the inclined surface above the discharge inclined plate 701. The discharge channel 702 itself is also inclined, so it will flow into the collection cylinder 703 through the discharge channel 702 and be collected by the collection cylinder 703. The channel area above the collection cylinder 703 connecting to the discharge channel 702 is small, which prevents a large amount of water in the collection cylinder 703 from entering the drying box 1, ensuring that the humidity in the drying box 1 is low, and the water in the collection cylinder 703 can flow out from the discharge pipe 704 by opening the electric control valve 705 for collection.

[0050] Example 2

[0051] Mango slices were dried using four drying methods: hot air drying (HAD), heat pump drying (HPD), freeze drying (FD), and microwave vacuum drying (MVD). The effects of different drying methods on the nutrients, antioxidant activity, and volatile compounds of mango were investigated.

[0052] 1. Color difference comparison, reference Figure 9 :

[0053] Color difference is one of the indicators for judging the appearance of mango slices. △E represents the degree of color difference between the fresh sample and the sample, L* represents brightness, and a* and b* values represent the color change from green to red and from blue to yellow, respectively. Figure 9 As shown in the figure, from the perspective of appearance, except for the hot air drying HAD sample, the other samples all maintain the original yellow color of mango. Among them, the heat pump component 3 drying HPD sample is golden yellow, the freeze drying FD sample is light yellow, the microwave vacuum drying MVD sample is dark yellow, and the hot air drying HAD sample is yellow-brown. In terms of color parameters, the drying process has a significant impact on the color of mango slices, such as Figure 9 As shown in Table b, the color difference values △E of mango slices obtained by four different drying methods are as follows: microwave vacuum drying MVD> hot air drying HAD> freeze drying FD heat pump drying> heat pump component 3 drying HPD, as shown in Figure 9 As shown in Table c and Table e, except for the fresh sample, the L* and b* values of the heat pump dried sample are the highest, and the microwave vacuum dried MVD sample is the lowest. Therefore, the surface of the HPD sample dried by heat pump component 3 is more glossy and yellowish, as shown in Table c. Figure 9 The maximum a* value of the hot air dried HAD sample is 17.20±0.75, and the minimum a* value of the freeze dried FD sample is 8.60±0.99, which indicates that the hot air dried HAD sample tends to be red, which is consistent with the Figure 9 Corresponding to table a in the middle, hot air drying (HAD) has a long drying time, low drying temperature and long-term contact with air. The mango samples undergo enzymatic browning during the drying process, resulting in a significant color change.

[0054] In summary, in terms of overall color difference in the drying experiment, the ΔE value of HPD dried by heat pump assembly 3 was the smallest, indicating that the color difference between HPD samples dried by heat pump assembly 3 and fresh samples was small, and compared with other drying methods, the original color of mango slices was better preserved.

[0055] 2. Effects of different drying methods on the nutritional content of mangoes:

[0056] As shown in Table 1, there was a significant difference in the soluble sugar content between the freeze-dried FD mango slices and the microwave vacuum dried MVD mango slices (P < 0.05), while there was no significant difference in the soluble sugar content between the freeze-dried FD, heat pump assembly 3 drying HPD, and hot air drying HAD mango slices (P > 0.05). The soluble sugar content of the mango slices prepared by microwave vacuum drying MVD was the lowest, at 56.75%. This is because the drying temperature of microwave vacuum drying MVD is higher than that of freeze-dried FD, and high temperature can not only lead to the decomposition and conversion of sugars, but also accelerate the Maillard reaction, reducing the soluble sugar content.

[0057] Table 1 shows that there were significant differences in soluble protein content between the different drying methods (P < 0.05). The microwave vacuum-dried MVD sample had the lowest soluble protein content, at 0.58 mg PE / g. The soluble protein contents of the mango slices dried with heat pump assembly 3 (HPD), hot air drying (HAD), and freeze-dried (FD) were 1.84, 1.78, and 3.08 times higher than those of the microwave vacuum-dried MVD sample, respectively. Compared with freeze-dried FD, the other three drying methods had a significant effect on soluble protein content (P < 0.05). This may be due to the fact that the drying temperatures for heat pump assembly 3 (HPD), hot air drying (HAD), and microwave vacuum drying (MVD) were all higher than those for freeze-dried FD, and higher temperatures can cause protein decomposition or denaturation. The lowest protein content in mango slices dried with microwave vacuum drying (MVD) may be due to the large temperature fluctuations during the drying process, which can lead to a high degree of protein denaturation.

[0058] As shown in Table 1, different drying methods have significant differences in the vitamin C content of mango slices (P < 0.05). The order of vitamin C content from high to low is: freeze drying FD > microwave vacuum drying MVD > heat pump component 3 drying HPD > hot air drying HAD. The vitamin C content of freeze-dried FD sample is 23.96 mg AAE / g, and the vitamin C content of microwave vacuum drying MVD sample is 20.47 mg AAE / g. Compared with the freeze-dried FD sample, the vitamin C content of the samples after heat pump component 3 drying HPD and hot air drying HAD decreased by 33.4% and 43.8% respectively. Mangoes are exposed to oxygen for a long time during heat pump component 3 drying HPD and hot air drying HAD, which can easily lead to oxidative decomposition of vitamin C and a large loss. Among them, the vitamin C content of the microwave vacuum drying MVD sample is lower than that of the freeze-dried FD, but significantly higher than that of the samples of the other two drying methods. This may be because microwave vacuum drying is in a vacuum state, which reduces the contact between oxygen and vitamin C and retains some vitamin C. The vitamin C content of the freeze-dried FD group sample is the highest, and the decomposition of vitamin C can be greatly reduced under a low-temperature vacuum environment.

[0059] The effects of different drying methods on the carotenoid content in mango are shown in Table 1. Compared with the freeze-dried FD sample, the carotenoid content of the samples of the other three drying methods was significantly different (P < 0.05). Among them, the freeze-dried FD sample group had the highest content. This is because freeze-dried FD directly sublimates water into gas under low temperature, effectively reducing the effect of drying temperature on vitamin C and also reducing the degradation of carotenoids. The hot air drying HAD sample group had the lowest content. The hot air drying HAD has a higher temperature and a longer drying time, which accelerates the decomposition of carotenoids. In summary, freeze-dried FD has the best effect on maintaining the nutritional content of dried mango.

[0060] Table 1 Nutritional content of dried mangoes by different drying methods

[0061]

[0062]

[0063] 3. Effects of different drying methods on the antioxidant capacity of mangoes Figure 10 :

[0064] DPPH free radicals and superoxide anion free radicals are often used to evaluate the antioxidant capacity of fruits and vegetables. The higher the DPPH scavenging rate and superoxide anion scavenging rate, the stronger the antioxidant capacity of the sample. Figure 10 As shown in the figure, compared with freeze-dried FD, the DPPH clearance rates of the other three drying methods were significantly different, among which there was no significant difference between hot air drying HAD and heat pump component 3 drying HPD samples (P>0.05). The DPPH clearance rates of the four drying methods were in the following order from large to small: freeze-dried FD> heat pump component 3 drying HPD> hot air drying HAD> microwave vacuum drying MVD. Among them, the DPPH clearance rate of freeze-dried FD samples was the highest, which was 32.59%. This may be because freeze-dried FD alleviated the decomposition of vitamin C in a low temperature and low pressure environment. The DPPH clearance rate of microwave vacuum drying MVD samples was the lowest, which was 13%. The superoxide anion clearance rate of freeze-dried FD samples had the same trend as DPPH. The superoxide anion clearance rate of freeze-dried FD sample group was the highest, which was 88%, and the microwave vacuum drying MVD sample group had the lowest, which was 79.46%. Microwave radiation caused some heat-sensitive substances in mango to decompose. In summary, freeze-dried FD samples had the best antioxidant capacity.

[0065] 4. Changes and differences in the aroma of dried mangoes with different drying methods, refer to Figure 11 、 Figure 12 as well as Figure 13 :

[0066] 1. Electronic nose analysis

[0067] Electronic nose is a kind of analytical instrument that simulates human sense of smell and can quickly identify the smell of fruits and vegetables. Figure 11As shown in the figure, the flavor substances in dried mango are mainly concentrated in W3S, W2W, W2S, W1S and W5S, namely alkanes, organic sulfides and aromatic compounds, alcohols, methane and nitrogen oxides. The response value of the W1W sensor shows that heat pump component 3 drying HPD > microwave vacuum drying MVD > hot air drying HAD > freeze drying FD; the response value of the W5S sensor shows that microwave vacuum drying MVD > heat pump component 3 drying HPD > freeze drying FD > hot air drying HAD; the response values of the W2W and W2S sensors show that heat pump component 3 drying HPD > hot air drying HAD > microwave vacuum drying MVD > freeze drying FD; the response value of the W1S sensor shows that heat pump component 3 drying HPD > hot air drying HAD > microwave vacuum drying MVD > freeze drying FD. There are significant differences in the effects of different drying methods on the main volatile components of dried mango. The response value of the main volatile substances in the dried mango dried by freeze drying FD is the lowest, indicating that the loss of volatile components of mango is greater during the drying process. The response value of the dried mango dried by heat pump component 3 drying HPD is higher. Compared to fresh mangoes, the alcohols, some aromatic compounds, and methane in the HPD dried mangoes by heat pump assembly 3 increased. Temperature promotes the transformation of substances in mangoes, resulting in an increase in some volatile components.

[0068] 2. GC-IMS analysis

[0069] The GC-IMS method was used to analyze the differences and changes in VOCs in mango samples dried by different methods. The analysis results are as follows: Figure 12 As shown in the figure, the fresh fruit two-dimensional atlas is used as a reference, and other dried sample atlases are used for subtraction. The white area after subtraction represents the same content of organic compounds, while the red and blue areas represent higher and lower content than the reference atlas, respectively. Figure 12 As can be seen from the figure, the four drying methods differed in volatile compounds compared to fresh mangoes; all four drying methods altered the volatile compounds in mangoes. Furthermore, significant differences in the types and contents of volatile compounds were observed between mango samples treated with the four drying methods, consistent with the radar image results from the electronic nose.

[0070] 3. GC-IMS fingerprint analysis of mangoes treated by different drying methods

[0071] Take the fingerprint spectrum for analysis to understand the complete organic information of volatile substances in each sample and the differences between samples. The background image is blue, and each light spot represents a volatile compound. The more concentrated the compound, the redder its color and the larger the light spot. The analysis results are as follows: Figure 13 As shown, Figure 13In the middle a frame, fresh mangoes contain more terpenes and sulfides. The volatile substances contained in the dried mangoes by different drying methods are mostly reduced compared with the fresh mangoes. The various aroma types detected in the dried mangoes by different drying methods have great changes. Compared with the other three drying methods, the dried mangoes dried by heat pump component 3 HPD retain more sulfides and olefins, indicating that heat pump component 3 HPD can better retain the aroma components of mangoes, which is consistent with the results of the electronic nose. Figure 13 As shown in box b, the content of aldehydes and ketones increased significantly after drying, as shown in Figure 13 As shown in box c, the VOC level of the dried mangoes freeze-dried FD is relatively the lowest. In theory, the flavor substances of freeze-dried FD should be close to those of the fresh sample. However, due to the long vacuum freeze-drying time, some chemical reactions occurred in the dried mangoes after long-term storage, resulting in changes in the aroma substances. The samples of hot air drying HAD have relatively high contents of substances such as benzaldehyde, ethyl acetate, 3-hydroxy-2-butanone, and methyl-5-heptene-2-one. Among them, the loss of mango aroma substances such as ocimene, limonene, and α-pinene is relatively large. In summary, heat pump component 3 drying HPD can well retain the volatile components of mangoes.

[0072] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The units and algorithm steps of each example described in the embodiment can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0073] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0074] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0075] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An internal circulation energy-saving heat pump fruit drying equipment, comprising a drying box (1), characterized in that: The side of the drying box (1) is movably connected to a sealed cover door (2), and the side of the drying box (1) away from the sealed cover door (2) is fixedly connected to a heat pump assembly (3). An exhaust port (4) is provided on the side of the interior of the drying box (1), and an air return port (5) is provided on the top of the interior of the sealed cover door (2). The bottom of the interior of the drying box (1) is movably connected to an output mechanism (6), and the top of the output mechanism (6) is movably connected to a drainage mechanism (8). The bottom of the interior of the drying box (1) is fixedly connected to a collecting mechanism (7), and the side of the drainage mechanism (8) is fixedly connected to a placement grid (9); The drainage mechanism (8) comprises a fixed spiral plate (801) that rotates synchronously with the output mechanism (6); a connecting plate (802) is provided on the side of the spiral plate (801); the bottom end of the connecting plate (802) contacts the upper surface of the spiral plate (801); the top end of the connecting plate (802) is fixedly connected to a limiting rod (803); the side of the limiting rod (803) is movably connected to a fixed plate (804); the side of the fixed plate (804) is fixedly connected to the interior of the drying box (1); a supporting spring (805) is provided on the side of the limiting rod (803); and the supporting spring (805) is located between the connecting plate (802) and the fixed plate (804).

2. The internal circulation energy-saving heat pump fruit drying equipment according to claim 1, characterized in that: The heat pump assembly (3) is in communication with the interior of the drying box (1) through the exhaust port (4) and the return air port (5); the sealing cover door (2) is fixedly connected to the side of the drying box (1) close to the intelligent collector (10); when the placement grid (9) moves, the placement grid (9) does not contact the intelligent collector (10).

3. The internal circulation energy-saving heat pump fruit drying equipment according to claim 2, characterized in that: The bottom end of the connecting plate (802) close to the side of the spiral plate (801) is provided with an inclined surface, the bottom end of the upper surface of the spiral plate (801) contacts the inclined surface of the side of the connecting plate (802), and the spiral plate (801) surrounds the side of the output shaft (602) in the output mechanism (6) for half a circle.

4. The internal circulation energy-saving heat pump fruit drying equipment according to claim 3, characterized in that: The bottom end of the connecting plate (802) is fixedly connected to a connecting rod (807), the bottom end of the spiral plate (801) is fixedly connected to a sealing block (808), the side of the sealing block (808) is movably connected to a gas cavity (806), and the side of the gas cavity (806) is fixedly connected to the interior of the drying box (1).

5. The internal circulation energy-saving heat pump fruit drying equipment according to claim 4, characterized in that: The bottom end of the gas cavity (806) is provided with an inclined surface, and the bottom end of the gas cavity (806) and the location of the inclined surface are provided with gas holes. The bottom end of the sealing block (808) is adapted to the bottom end inside the gas cavity (806), and the sealing block (808) seals the inside of the gas cavity (806).

6. The internal circulation energy-saving heat pump fruit drying equipment according to claim 1, characterized in that: The output mechanism (6) comprises a controllable servo motor (601), the top end of the servo motor (601) is fixedly connected to an output shaft (602), the bottom end of the side of the output shaft (602) is fixedly connected to an output bevel gear (603), the side of the output bevel gear (603) is meshed with a connecting gear rod (604), the side of the connecting gear rod (604) away from the output bevel gear (603) is meshed with a synchronous bevel gear (605), the interior of the synchronous bevel gear (605) is fixedly connected to a synchronous shaft (606), and the top ends of the sides of the output shaft (602) and the synchronous shaft (606) are both fixedly connected to the interior of the spiral plate (801).

7. The internal circulation energy-saving heat pump fruit drying equipment according to claim 6, characterized in that: An output shaft (602) and a synchronous shaft (606) are provided on both sides of the placement grid (9); the output shaft (602), the synchronous shaft (606) and the spiral plates (801) at the top of the two are mirror-symmetrical; a synchronous belt (607) is fixedly connected to the bottom end of the side of the output shaft (602); the synchronous belt (607) connects the output shafts (602) on both sides, and the synchronous belt (607) enables the output shafts (602) on both sides of the placement grid (9) to rotate synchronously.

8. The internal circulation energy-saving heat pump fruit drying equipment according to claim 1, characterized in that: The collecting mechanism (7) comprises discharge inclined plates (701) located on both sides of the bottom end inside the drying box (1), the height of the two discharge inclined plates (701) increases from the sides close to each other to the sides away from each other, and a discharge channel (702) is opened in the sides close to each other of the two discharge inclined plates (701), and the height of the side of the discharge channel (702) away from the sealing cover door (2) is lower than the height of the side close to the sealing cover door (2).

9. The internal circulation energy-saving heat pump fruit drying equipment according to claim 8, characterized in that: A collecting cylinder (703) is provided at the bottom end of the discharge channel (702) away from the side of the sealing cover door (2). The collecting cylinder (703) is communicated with the discharge channel (702). A discharge pipe (704) is fixedly connected to the bottom end of the collecting cylinder (703). An electric control valve (705) is fixedly connected to the side of the discharge pipe (704). The electric control valve (705) is located outside the drying box (1) away from the side of the collecting cylinder (703).

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