A drying treatment method capable of effectively preserving active ingredients and aroma substances of plum blossom

Abstract

The application discloses a kind of dry processing method effectively preserving plum blossom active ingredient and aroma substance, including harvesting, washing, using microwave hot air drying device to the plum blossom described above is dried, to the plum blossom of drying is washed with S2, then again using microwave hot air drying device is dried, continuous processing 3 times.The application proposes different drying process for plum blossom for different purposes, microwave hot air drying treatment is carried out to plum blossom used as medicinal materials, which can effectively improve the quality of plum blossom, maximize the active ingredients such as chlorogenic acid, quercetin and amino acid in plum blossom;hot air drying treatment is carried out to plum blossom used as scented tea, which maximizes the volatile components and aroma in plum blossom.In addition, the application uses microwave hot air drying device, so that the drying effect is better, and this method has low energy consumption and short time consumption, which greatly shortens the production cycle of plum blossom medicinal materials.

Description

Technical Field

[0001] This invention belongs to the field of drying technology, specifically relating to a drying method that effectively preserves the active ingredients and aroma substances of plum blossoms. Background Technology

[0002] Plum blossom is the first among China's ten famous flowers. It is listed as one of the Four Gentlemen along with orchid, bamboo, and chrysanthemum, and is also known as one of the Three Friends of Winter along with pine and bamboo. In traditional Chinese culture, plum blossom inspires people to strive for excellence with its noble, strong, and humble character. It blooms before all other flowers in the severe cold, bringing spring to the world. Plum blossoms are white and elegant, blooming in late winter and early spring. Its branches are ancient and gnarled, making it especially valuable for ornamental purposes when planted as a bonsai or garden tree.

[0003] Plum blossoms possess excellent medicinal properties, as recorded in the Chinese Pharmacopoeia. They are said to have the effects of "soothing the liver and harmonizing the stomach, resolving phlegm and dissipating nodules," and are effective in treating loss of appetite and liver and stomach ailments. This is mainly due to the action of phenolic acid compounds, primarily chlorogenic acid, and flavonoids, primarily quercetin, in plum blossoms, which also give them antioxidant and anti-tumor functions. Plum blossom medicinal materials are usually dried after harvesting and then soaked in water or decocted for oral administration. Post-harvest drying is a crucial step in the processing of traditional Chinese medicinal materials, and its results significantly affect the quality of plum blossom medicinal materials.

[0004] Traditional drying methods include air drying, hot air drying, and microwave drying, but their drying effects are not ideal. Previous research results have shown that traditional drying methods can significantly reduce the content of chlorogenic acid, an indicator substance in plum blossoms, while microwave and hot air combined drying methods can better preserve chlorogenic acid and various flavonoids.

[0005] The related technology includes Chinese invention patent document CN113154803A, which discloses a microwave hot air drying device and drying method. It includes a microwave drying module comprising a drying chamber for drying a dialyzer and a microwave induction component. The drying chamber includes an inlet pipe and an exhaust pipe, and the microwave induction component is installed inside the drying chamber. A pressure regulating module includes a first pressure regulating valve and a feedback gas path for measuring gas pressure; the first pressure regulating valve is connected to the feedback gas path. A hot and cold air switching module includes a reversing valve and a heater; one end of the reversing valve is connected to the first pressure regulating valve; the heater includes an inlet end and an outlet end, and the inlet end of the heater is connected to the reversing valve.

[0006] The microwave hot air drying device provided by the above solution solves the problems of slow drying speed and easy damage of fiber membrane bundles in the existing dialyzer drying process. However, in the processing, when the plum blossom is microwave heated and then dried, the air needs to be heated by a heater. Driving the heater requires a certain amount of energy, which increases the energy consumption of the equipment. The heat energy generated during the microwave generator heating process cannot be utilized, resulting in energy waste. Moreover, after heating, the plum blossom sample needs to be transferred to the drying equipment for drying. Manual transfer requires a lot of time and effort, which affects the processing efficiency.

[0007] Therefore, a microwave hot air drying device is proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a drying method that effectively preserves the active ingredients and aroma substances of plum blossoms, thereby solving the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a drying treatment method for effectively preserving the active ingredients and aroma substances of plum blossoms, comprising the following steps:

[0010] S1: Harvesting: Pick the small green calyx plum blossoms that have not yet opened and transport them in breathable containers;

[0011] S2: Water washing: Cold water and hot water are used for treatment in sequence;

[0012] S3: The plum blossoms above are dried using a microwave hot air drying device;

[0013] S4: The dried plum blossoms are washed with water as in S2, and then dried using a microwave hot air drying device. This process is repeated 3 times.

[0014] Preferably, in step S1, the harvesting time is after the dew has dried on a sunny day.

[0015] In any of the above solutions, it is preferred that, in step S1, the breathable container includes a basket or a plastic basket.

[0016] In any of the above schemes, it is preferred that in step S2, the cold water treatment at 2-10°C is performed for 3-5 minutes, followed by the hot water treatment at 55-65°C for 3-5 minutes.

[0017] In steps S3 and S4, the microwave hot air drying device includes:

[0018] The device body 1 has a heating chamber and a drying chamber inside. A sealing door adapted to the heating chamber and the drying chamber is rotatably installed at the front end of the device body. A control panel is also provided at the front end of the device body. A drying rack is provided inside the drying chamber.

[0019] The first heat exchange tube is disposed on the side wall of the heating cavity. A microwave generator electrically connected to the control panel is also disposed at the top of the heating cavity. A focusing plate is also disposed on the side wall of the heating cavity.

[0020] A heat exchange box is provided at the top of the drying chamber. A second heat exchange tube is provided inside the heat exchange box. A connecting pipe is provided between the second heat exchange tube and the first heat exchange tube. A circulating water pump is also fixedly connected between the second heat exchange tube and the connecting pipe.

[0021] An air inlet slot is provided on the side wall of the heat exchange box and extends to the outside of the main body of the device. An air outlet slot is provided on the side wall at the bottom of the drying chamber. Both the air inlet slot and the air outlet slot are provided with air permeable plates.

[0022] Preferably, in any of the above embodiments, the heat exchange box is equipped with a heater that is electrically connected to the control panel.

[0023] Preferably, in any of the above embodiments, the heat exchange box is further provided with a temperature sensor electrically connected to the control panel.

[0024] In any of the above embodiments, it is preferred that a hot air duct is fixedly connected to the bottom of the heat exchange box, a heat-conducting fan is installed inside the hot air duct, and multiple through holes are evenly opened on the top wall of the hot air duct, with the top of the through holes extending into the heat exchange box.

[0025] In any of the above embodiments, a preferred embodiment is provided with an opening groove at the center of the main body of the device. The two ends of the opening groove are respectively connected to the heating chamber and the drying chamber. An automatic transfer assembly is also provided in the opening groove. The automatic transfer assembly includes a conveyor belt disposed in the main body of the device. One end of the conveyor belt is located at the bottom end of the heating chamber, and the other end of the conveyor belt extends to the drying rack in the drying chamber. The top wall of the conveyor belt is flush with the top wall of the drying rack. A movable groove is provided in the middle of the opening groove. The bottom wall of the movable groove extends above the conveyor belt. A plurality of electric telescopic rods electrically connected to the control panel are evenly arranged at the top of the movable groove. The extended ends of the plurality of electric telescopic rods are fixedly connected to a sealing plate.

[0026] In any of the above embodiments, it is preferred that the conveyor belt is made of a high-temperature resistant material, a plurality of conveyor rollers are evenly arranged inside the conveyor belt, and a motor is also arranged in the middle of the main body of the device, with the output end of the motor fixedly connected to the central shaft of one of the conveyor rollers.

[0027] The technical effects and advantages of this invention are as follows: 1. This invention uses cold water and hot water for sequential treatment, which can effectively improve the quality of plum blossoms. Moreover, the use of microwave hot air drying device makes the drying effect better, maximizing the preservation of active ingredients and aroma in plum blossoms. Plum blossom medicinal materials are dried and preserved in the way that maximizes the content of chlorogenic acid, quercetin, amino acids, etc. In addition, this method has low energy consumption and short time consumption, which greatly shortens the production cycle of plum blossom medicinal materials.

[0028] 2. This invention starts the microwave generator via the control panel. At this time, the microwave generator can heat the sample at high temperature. During the high-temperature heating process, the focusing plate on the side wall of the heating chamber can concentrate the heat energy in the heating chamber and heat the heat transfer fluid in the first heat exchange tube. At this time, the heat transfer fluid in the first heat exchange tube can enter the second heat exchange tube through the connecting pipe and circulate. The heat transfer fluid in the second heat exchange tube after heating can heat the air in the heat exchange box. At this time, the heat transfer fan in the hot air tube can introduce the air in the heat exchange box into the drying chamber, which facilitates the drying of the sample on the drying rack. Through the continuous heat exchange of the heat transfer fluid in the first and second heat exchange tubes, the heat energy generated by the microwave generator in the heating chamber can be recovered and utilized. This avoids heating the air through the heater for a long time, reduces energy consumption, saves energy and is environmentally friendly, and is beneficial to the drying of the sample.

[0029] 3. This invention uses a sealing plate within the movable slot to isolate the heating chamber and the drying chamber, reducing heat loss and facilitating sample processing. After heating is complete, the operator starts the motor via the control panel. The motor drives one of the conveyor rollers to rotate, which in turn drives the conveyor belt to rotate within the heating chamber, transferring the sample on the conveyor belt. Simultaneously, energizing the electric telescopic rod causes the sealing plate to slide upwards, allowing it to slide out of the opening slot and connect the heating chamber and the drying chamber. The conveyor belt then allows the heated sample to quickly enter the drying chamber, improving sample transfer efficiency, reducing operator steps and workload, and ultimately increasing sample processing efficiency. Attached Figure Description

[0030] Figure 1 This is a process flow diagram of the present invention;

[0031] Figure 2 This is a schematic diagram of the overall structure of a microwave hot air drying device according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic cross-sectional view of the front end of the device body in an embodiment of the present invention;

[0033] Figure 4 This is a side cross-sectional view of the main body of the device in an embodiment of the present invention;

[0034] Figure 5 This is a frontal cross-sectional view of the main body of the device in an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the combined structure of the first heat exchange tube and the second heat exchange tube in an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the structure inside the drying chamber in an embodiment of the present invention.

[0037] In the diagram: 1. Main body of the device; 2. Sealed door; 3. Control panel; 4. Microwave generator; 5. Focusing plate; 6. First heat exchange tube; 7. Conveyor belt; 8. Opening slot; 9. Heating chamber; 10. Motor; 11. Drying rack; 12. Ventilation plate; 13. Drying chamber; 14. Hot air duct; 15. Heat exchange box; 16. Air outlet slot; 17. Movable slot; 18. Sealing plate; 19. Connecting pipe; 20. Conveyor roller; 21. Heater; 22. Air inlet slot; 23. Second heat exchange tube; 24. Circulating water pump; 25. Through hole; 26. Heat-conducting fan; 27. Temperature sensor; 28. Electric telescopic rod. Detailed Implementation

[0038] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0041] Example 1 (S1):

[0042] The samples were dried naturally at room temperature for 2 days, turning them over daily.

[0043] Example 2 (S2):

[0044] The samples were dried using a hot air drying method, slowly drying them in an oven at 50°C for 4 hours.

[0045] Example 3 (S3):

[0046] The samples were dried using a microwave drying method. After heating the samples on high in a microwave oven for 1 minute, the flower materials were turned over and heated again for 1 minute.

[0047] Example 4 (S4):

[0048] refer to Figure 1 A method for drying plum blossoms includes the following steps:

[0049] Step 1: Harvesting: Choose a sunny morning between 9:00 and 12:00 in March or April to pick small green calyx plum blossoms that have not yet opened (mainly small and medium buds, characterized by plump buds with a slight white tip). Pick the blossoms that are free from pests and diseases and transport them in breathable containers.

[0050] Step 2: Water washing: Use cold water and hot water successively for treatment;

[0051] Step 3: Dry the plum blossoms using a microwave hot air drying device;

[0052] Step 4: Wash the dried plum blossoms with water (S2), then dry them with a microwave hot air dryer for three consecutive times, and finally package them.

[0053] In step 1, the harvesting time is after the dew has dried on a sunny day.

[0054] In step 1, the breathable container includes baskets and plastic baskets.

[0055] In step 2, the cold water treatment at 2-10°C is carried out for 3-5 minutes, followed by the hot water treatment at 55-65°C for 3-5 minutes.

[0056] Please see Figures 2 to 7 A microwave hot air drying apparatus, comprising:

[0057] The device body 1 has a heating chamber 9 and a drying chamber 13 inside. A sealing door 2 that is compatible with the heating chamber 9 and the drying chamber 13 is rotatably installed at the front end of the device body 1. A control panel 3 is also provided at the front end of the device body 1. A drying rack 11 is provided inside the drying chamber 13.

[0058] The first heat exchange tube 6 is located on the side wall of the heating chamber 9. The top of the heating chamber 9 is also equipped with a microwave generator 4 that is electrically connected to the control panel 3. A focusing plate 5 is also provided on the side wall of the heating chamber 9.

[0059] Heat exchange box 15 is located at the top of drying chamber 13. A second heat exchange tube 23 is installed inside the heat exchange box 15. A connecting pipe 19 is provided between the second heat exchange tube 23 and the first heat exchange tube 6. A circulating water pump 24 is also fixedly connected between the second heat exchange tube 23 and the connecting pipe 19.

[0060] An air inlet groove 22 is provided on the side wall of the heat exchange box 15 and extends to the outside of the main body 1 of the device. An air outlet groove 16 is provided on the side wall at the bottom of the drying chamber 13. Both the air inlet groove 22 and the air outlet groove 16 are provided with a breathable plate 12.

[0061] The heat exchange box 15 is equipped with a heater 21 that is electrically connected to the control panel 3.

[0062] The heat exchange box 15 is also equipped with a temperature sensor 27 that is electrically connected to the control panel 3.

[0063] A hot air duct 14 is fixedly connected to the bottom of the heat exchange box 15. A heat-conducting fan 26 is installed inside the hot air duct 14. Multiple through holes 25 are evenly opened on the top wall of the hot air duct 14, and the top of the through holes 25 extends into the heat exchange box 15.

[0064] In this embodiment, after the user places the sample into the heating chamber 9, the microwave generator 4 is activated via the control panel 3. The microwave generator 4 then heats the sample at a high temperature. During this process, the focusing plate 5 on the side wall of the heating chamber 9 concentrates the heat energy within the chamber, heating the heat transfer fluid in the first heat exchange tube 6. The circulating water pump 24 then pumps the heat transfer fluid from the first heat exchange tube 6 into the second heat exchange tube 23 via the connecting pipe 19, where it circulates. After heating... The heat-conducting liquid in the second heat exchange tube 23 can heat the air in the heat exchange box 15. At this time, the heat-conducting fan 26 in the hot air tube 14 can guide the air in the heat exchange box 15 into the drying chamber 13, which is convenient for drying the sample on the drying rack 11. Through the continuous heat exchange of the heat-conducting liquid in the first heat exchange tube 6 and the second heat exchange tube 23, the heat energy generated by the microwave generator 4 in the heating chamber 9 can be recovered and utilized. This avoids heating the air through the heater 21 for a long time, which can reduce energy consumption, save energy and protect the environment, and is beneficial to the drying of the sample.

[0065] As one embodiment of the present invention, refer to Figures 2-4A microwave hot air drying device further includes: an opening groove 8 opened at the center of the device body 1, the two ends of the opening groove 8 being connected to a heating chamber 9 and a drying chamber 13 respectively, and an automatic transfer component is also provided in the opening groove 8. The automatic transfer component includes a conveyor belt 7 provided in the device body 1, one end of the conveyor belt 7 being located at the bottom end of the heating chamber 9, and the other end of the conveyor belt 7 extending to the drying rack 11 in the drying chamber 13, and the top wall of the conveyor belt 7 being flush with the top wall of the drying rack 11.

[0066] The conveyor belt 7 is made of high temperature resistant material. Multiple conveyor rollers 20 are evenly arranged inside the conveyor belt 7. A motor 10 is also arranged in the middle of the main body 1 of the device. The output end of the motor 10 is fixedly connected to the central shaft of one of the conveyor rollers 20.

[0067] An movable groove 17 is provided in the middle of the opening groove 8, and the bottom wall of the movable groove 17 extends above the conveyor belt 7.

[0068] Multiple electric telescopic rods 28 electrically connected to the control panel 3 are evenly arranged at the top of the active slot 17, and the extended ends of the multiple electric telescopic rods 28 are fixedly connected to the sealing plate 18.

[0069] In this embodiment, during use, the sealing plate 18 in the movable groove 17 can isolate the heating chamber 9 and the drying chamber 13, reducing heat loss and facilitating sample processing. After heating is complete, the operator starts the motor 10 through the control panel 3. The motor 10 drives one of the conveyor rollers 20 to rotate. At this time, the conveyor roller 20 drives the conveyor belt 7 to rotate in the heating chamber 9, transferring the sample on the conveyor belt 7. At this time, the electric telescopic rod 28 is energized, which drives the sealing plate 18 to slide upward, allowing the sealing plate 18 to slide out from the opening groove 8, thus connecting the heating chamber 9 and the drying chamber 13. At this time, the heated sample can quickly enter the drying chamber 13 through the conveyor belt 7, improving the sample transfer efficiency, saving the operator's operation steps, reducing the operator's workload, and improving the sample processing efficiency.

[0070] Working principle: First, open the sealing door 2 on the main body 1 of the device and place the sample on the conveyor belt 7 on the heating chamber 9. At this time, start the microwave generator 4 through the control panel 3. The microwave generator 4 can heat the sample at high temperature. During use, the sealing plate 18 in the movable groove 17 can isolate the heating chamber 9 and the drying chamber 13, which can reduce heat loss and facilitate sample processing. After heating is completed, the operator starts the motor 10 through the control panel 3. The motor 10 can drive one of the conveyor rollers 20 to rotate. At this time, the conveyor roller 20 can drive the conveyor belt 7 to rotate in the heating chamber 9, which can transfer the sample on the conveyor belt 7. At this time, the electric telescopic rod 28 is energized, and the electric telescopic rod 28 can drive the sealing plate 18 to rotate in the heating chamber 9. The sealing plate 18 slides upward, allowing it to slide out from the opening groove 8, thus connecting the heating chamber 9 and the drying chamber 13. At this time, the heated sample can be quickly transferred into the drying chamber 13 via the conveyor belt 7, improving the sample transfer efficiency, saving the operator's operation steps, reducing the operator's workload, and improving the sample processing efficiency. At this time, the heat-conducting fan 26 can draw outside air into the heat exchange box 15 from the air inlet groove 22, and then start the heater 21 to heat the air. The heated air can enter the drying chamber 13 through the through hole 25 to dry the sample on the drying rack 11. The temperature sensor 27 can monitor the temperature of the air in the heat exchange box 15 in real time.

[0071] During the high-temperature heating of the sample by the microwave generator 4, the focusing plate 5 on the side wall of the heating chamber 9 can concentrate the heat energy in the heating chamber 9 and heat the heat-conducting liquid in the first heat exchange tube 6. At this time, the heat-conducting liquid in the first heat exchange tube 6 can enter the second heat exchange tube 23 through the connecting pipe 19 and circulate. The heat-conducting liquid in the second heat exchange tube 23 after heating can heat the air in the heat exchange box 15. At this time, the heat-conducting fan 26 in the hot air tube 14 can introduce the air in the heat exchange box 15 into the drying chamber 13, which facilitates the drying of the sample on the drying rack 11. Through the continuous heat exchange of the heat-conducting liquid in the first heat exchange tube 6 and the second heat exchange tube 23, the heat energy generated by the microwave generator 4 in the heating chamber 9 can be recovered and utilized. This avoids heating the air through the heater 21 for a long time, reduces energy consumption, saves energy and is environmentally friendly, and is beneficial to the drying of the sample.

[0072] The active ingredient contents of each sample after different drying methods are shown in Table 1. In the samples dried by natural drying, the chlorogenic acid content was 66.74±0.25 mg / g, the catechin content was 24.41±0.30 mg / g, and the flavonoid content ranged from 13.06 to 28.64 mg / g. In the samples dried by hot air drying, the chlorogenic acid content was 55.97±0.67 mg / g, which was the lowest among the four drying methods, the catechin content was 26.00±0.41 mg / g, and the flavonoid content ranged from 14.37 to 29.52 mg / g. In the samples dried by microwave drying, the measured chlorogenic acid content was 80.67±0.22 mg / g, catechin content was 26.48±0.40 mg / g, and flavonoid content ranged from 15.12 to 33.68 mg / g, with rutin content at 33.68±0.42 mg / g and quercetin content at 20.86±0.04 mg / g. In sample S4, the chlorogenic acid content was 83.69±0.17 mg / g, catechin content was 28.61±0.24 mg / g, rutin content was 34.04±0.49 mg / g, and hyperoside content was 14.03±0.21 mg / g, all the highest among the four drying methods. Chlorogenic acid is an indicator component of plum blossoms. The sample obtained by the combined microwave and hot air drying method had the highest chlorogenic acid content, indicating that this method is the most suitable for preparing plum blossom medicinal materials.

[0073] Table 1:

[0074]

[0075] Naturally dried samples contained 17 of the 23 active volatile components, including aroma components (Table 2). Benzaldehyde was the most abundant volatile component in the naturally dried plum blossom samples, accounting for 90.68%; benzyl alcohol, with a mild floral aroma, was the second most abundant component at 0.91%; acetic acid was the third most abundant at 0.88%, with a slightly pungent odor. In addition, isovaleric acid and n-valeric acid, both of which have a cheese-like odor, were also detected in the naturally dried flowers; isovaleraldehyde, with a chocolate-like odor; dihydroactinol, with a coumarin-like odor; and 2-methylbutanal, with a fermented bread-like odor.

[0076] Table 2 Aroma components and contents of 'Xiaolve' in natural drying method

[0077]

[0078]

[0079] In the hot air drying method, 10 of the 27 active volatile components were aroma components (Table 3). Benzaldehyde content remained the highest at 61.46%; acetic acid content was second at 14.36%; and isovaleraldehyde content was third at 3.01%. In addition, the plum blossom samples obtained by the hot air drying method also produced 2-methylbutyraldehyde with a fermented and roasted aroma; and dihydroactinol with a coumarin aroma. However, unlike flowers dried by natural drying, stable hot air drying at 50°C produced 2,3-butanediol with a fruity and buttery aroma, which is the result of continuous heating of free amino acids in the plum blossoms; 2-acetylfuran with a sweet balsamic aroma; and butyric anhydride with a buttery aroma.

[0080] Table 3 Aroma components and contents of 'Xiaolve' inhot air drying method

[0081]

[0082] The alkane content of plum blossom samples increased after microwave treatment, but the content of aroma components and various aroma components decreased. Only 9 of the 24 effective volatile compounds were aroma components (Table 4), with formic acid being the most abundant at 20.91%, followed by 2-methylbutyraldehyde at 8.99%, and benzaldehyde at 6.51%. Similar to naturally dried and hot-air dried samples, microwave-dried flowers also contained 2-methylbutyraldehyde, benzaldehyde, dihydroactinolone, and isovaleraldehyde. Furthermore, camphor with a woody aroma and 3,5-dihydroxyacetophenone with a strong floral fragrance were detected in microwave-dried flowers, giving the samples a fresh aroma unlike those from other drying methods.

[0083] Table 4. Aroma components and contents of 'Xiaolve' in microwave drying method

[0084]

[0085] Compared to other drying methods, the hot air-microwave drying method used in this application yielded the fewest aroma compounds in the flowers, with only 6 of the 18 effective volatile components (Table 5). This is because the esters in the fresh plum blossom samples volatilize under rapid heating. Among the 6 aroma compounds, 2-methylbutyraldehyde had the highest content at 9.37%, followed by isovaleraldehyde at 5.35%, and formic acid at 3.58%. Notably, benzaldehyde was not detected in the flowers after the combined drying process. Furthermore, 2,3-butanediol, an aromatic substance found only in hot air drying, was detected during the microwave-hot air combined drying process. It is a product of free polysaccharides in plum blossoms generated at high temperatures.

[0086] Table 5 Aroma components and contents of 'Xiaolve' in microwave and hot air combined drying method

[0087]

[0088] After being processed using different drying techniques, the volatile substances in the small green calyx plum blossoms all showed a significant loss. The total volatile content obtained from the four drying methods, ranked from highest to lowest, was: natural drying > hot air drying > microwave drying > combined microwave and hot air drying. Therefore, in industrial production, the intended use of the plum blossoms should be considered when drying them. For medicinal purposes, the combined microwave and hot air drying method should be considered, as it is faster, more efficient, and retains phenolic compounds with antioxidant properties relatively well, making it suitable for large-scale industrial production. However, if the plum blossoms are to be used as a tea, the more comprehensive hot air drying method, which removes more volatile substances, should be considered for a better drinking experience.

[0089] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A drying process that effectively preserves the active ingredients and aroma substances of plum blossoms, characterized in that: Includes the following steps: S1: Harvesting: Pick small green calyx plum blossoms with slightly white tips and buds that are not fully open, and transport them in breathable containers; S2: Water washing: Cold water and hot water are used for treatment in sequence; S3: The plum blossoms above are dried using a microwave hot air drying device; S4: The dried plum blossoms are washed with water as in S2, and then dried using a microwave hot air drying device. This process is repeated 3 times. The microwave hot air drying device includes: The device body (1) has a heating chamber (9) and a drying chamber (13) inside. A sealing door (2) adapted to the heating chamber (9) and the drying chamber (13) is rotatably installed at the front end of the device body (1). A control panel (3) is also provided at the front end of the device body (1). A drying rack (11) is provided inside the drying chamber (13). The first heat exchange tube (6) is located on the side wall of the heating chamber (9). The top of the heating chamber (9) is also provided with a microwave generator (4) electrically connected to the control panel (3). A focusing plate (5) is also provided on the side wall of the heating chamber (9). A heat exchange box (15) is set at the top of the drying chamber (13). A second heat exchange tube (23) is provided inside the heat exchange box (15). A connecting pipe (19) is provided between the second heat exchange tube (23) and the first heat exchange tube (6). A circulating water pump (24) is also fixedly connected between the second heat exchange tube (23) and the connecting pipe (19). An air inlet groove (22) is provided on the side wall of the heat exchange box (15) and extends to the outside of the main body (1). An air outlet groove (16) is provided on the side wall at the bottom of the drying chamber (13). Both the air inlet groove (22) and the air outlet groove (16) are provided with a breathable plate (12).

2. The drying method for effectively preserving the active ingredients and aroma substances of plum blossoms according to claim 1, characterized in that: In step S1, the harvesting time is after the dew has dried on a sunny day.

3. The drying method for effectively preserving the active ingredients and aroma substances of plum blossoms according to claim 1, characterized in that: In step S1, the breathable container includes baskets and plastic baskets.

4. The drying method for effectively preserving the active ingredients and aroma substances of plum blossoms according to claim 1, characterized in that: In step S2, the cold water treatment at 2-10°C is performed for 3-5 minutes, followed by the hot water treatment at 55-65°C for 3-5 minutes.

5. The drying method for effectively preserving the active ingredients and aroma substances of plum blossoms according to claim 1, characterized in that: The heat exchange box (15) is equipped with a heater (21) that is electrically connected to the control panel (3).

6. The drying method for effectively preserving the active ingredients and aroma substances of plum blossoms according to claim 5, characterized in that: The heat exchange box (15) is also equipped with a temperature sensor (27) that is electrically connected to the control panel (3).

7. The drying method for effectively preserving the active ingredients and aroma substances of plum blossoms according to claim 6, characterized in that: The bottom end of the heat exchange box (15) is fixedly connected to a hot air duct (14), and a heat-conducting fan (26) is provided inside the hot air duct (14). Multiple through holes (25) are evenly opened on the top wall of the hot air duct (14), and the top of the through holes (25) extends into the heat exchange box (15).

8. The drying method for effectively preserving the active ingredients and aroma substances of plum blossoms according to claim 7, characterized in that: An opening groove (8) is provided at the center of the main body (1) of the device. The two ends of the opening groove (8) are connected to the heating chamber (9) and the drying chamber (13) respectively. An automatic transfer component is also provided in the opening groove (8). The automatic transfer component includes a conveyor belt (7) provided in the main body (1). One end of the conveyor belt (7) is located at the bottom end of the heating chamber (9). The other end of the conveyor belt (7) extends to the drying rack (11) in the drying chamber (13). The top wall of the conveyor belt (7) is flush with the top wall of the drying rack (11). A movable groove (17) is provided in the middle of the opening groove (8). The bottom wall of the movable groove (17) extends to the top of the conveyor belt (7). A plurality of electric telescopic rods (28) electrically connected to the control panel (3) are evenly provided at the top of the movable groove (17). The extended ends of the plurality of electric telescopic rods (28) are fixedly connected to a sealing plate (18).

9. The drying method for effectively preserving the active ingredients and aroma substances of plum blossoms according to claim 8, characterized in that: The conveyor belt (7) is made of high temperature resistant material. Multiple conveyor rollers (20) are evenly arranged inside the conveyor belt (7). A motor (10) is also arranged in the middle of the main body (1) of the device. The output end of the motor (10) is fixedly connected to the central shaft of one of the conveyor rollers (20).

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