Preparation method of freeze-dried coriaria sinica bacteria

Abstract

The invention relates to the technical field of food processing, in particular to a preparation method of freeze-dried coriaria sinica. The freeze-dried coriaria sinica is prepared through a multiple gradient freeze-drying method, firstly, water in the coriaria sinica is converted into ice crystals, meanwhile, overlarge ice crystals can be prevented from being generated, the overlarge ice crystals are prevented from damaging coriaria sinica cells, then the ice crystals are quickly sublimated into a gaseous state through primary freeze-drying, most of the water in the coriaria sinica is removed, and the freeze-dried coriaria sinica is obtained. Finally, the moisture adsorbed on the surface of the coriaria sinica is sublimated into a gaseous state again through freeze-drying again to obtain the freeze-dried coriaria sinica with low moisture content and small nutrient substance loss, so that the natural color, aroma and flavor of the coriaria sinica can be reserved to the greatest extent, and the nutritional ingredients of the coriaria sinica can be reserved to the greatest extent. The method is a very valuable food processing method.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and particularly relates to a preparation method of freeze-dried Coriolus versicolor. Background Art

[0002] Coriolus versicolor is a common edible and medicinal fungus, widely distributed in temperate and subtropical regions, often growing on decaying trees and dead leaves. It is rich in vegetable protein and is a good source of food for vegetarians and those with a need for animal protein. At the same time, it contains abundant dietary fiber, especially soluble fiber. Regular consumption helps to promote intestinal health, enhance gastrointestinal motility, and prevent constipation. In addition, Coriolus versicolor is also rich in minerals such as potassium, phosphorus, calcium, and iron. Potassium helps to maintain the balance of water and electrolytes in the body, iron helps in the formation of hemoglobin to prevent anemia, and calcium is a mineral essential for bone health.

[0003] Although Coriolus versicolor has excellent edible value, under conventional preservation methods, Coriolus versicolor is prone to spoilage and loss of edible value. Therefore, it is necessary to prepare fresh products into dried fungi that can be stored for a long time. However, there are still many defects in the existing methods for preparing dried fruits. Natural drying takes a long time and is easily contaminated by dust and pests in the air, and long-term exposure to sunlight easily leads to loss of nutrients; the method of drying with a dryer is prone to over-drying and still containing moisture, and the problem of nutrient loss still exists.

[0004] In view of the above problems, the present invention provides a solution. Summary of the Invention

[0005] The object of the present invention is to provide a preparation method of freeze-dried Coriolus versicolor, and the prepared freeze-dried Coriolus versicolor can not only be stored for a long time, but also has less loss of nutrients.

[0006] To achieve the above object, the present invention adopts the following technical scheme: A preparation method of freeze-dried Coriolus versicolor includes the following steps:

[0007] S1: Transport the fresh Coriolus versicolor raw materials to the unloading area in the factory, remove the damaged, rotten, and overripe Coriolus versicolor, remove the fruit stalks, and then transfer them to an ultrasonic cleaner for ultrasonic cleaning to remove soil and impurities;

[0008] S2: After ultrasonic cleaning, cut the Coriolus versicolor into small pieces. After cutting, lay the small pieces of Coriolus versicolor on a tray, and pay attention not to overlap the Coriolus versicolor during the laying process;

[0009] S3: Turn on the quick-freezing cold storage cooling device to pre-freeze the coriaria sinica. Set the cooling rate of the cold storage to 5 - 8 °C / min and cool the cold storage to -10 °C, and maintain for 30 - 45 min. Then set the cooling rate of the cold storage to 4 - 6 °C / min and cool the cold storage to -18 °C, and maintain for 30 - 45 min. Then set the cooling rate of the cold storage to 8 - 10 °C and cool the cold storage to -40 °C, and maintain for 1 - 1.5 h;

[0010] S4: Transfer the coriaria sinica to the freeze-drying chamber. At the same time, verify the sealing integrity of the chamber door to ensure the normal operation of the freeze-drying chamber. After verifying the sealing integrity of the chamber door, turn on the vacuum pump and pump the freeze-drying chamber to a vacuum degree of 10 - 15 Pa, and maintain the vacuum degree at 10 - 15 Pa. Then turn on the heating plate and condenser of the freeze-drying chamber, and keep the temperature of the coriaria sinica at -26 °C for preliminary freeze-drying for 10 - 12 h to directly convert solid ice into gas to remove the moisture in the coriaria sinica;

[0011] S5: After the preliminary freeze-drying is completed, adjust the vacuum degree to 35 - 40 Pa, adjust the temperatures of the heating plate and condenser of the freeze-drying chamber, and keep the temperature of the coriaria sinica at -18 °C for secondary freeze-drying for 6 - 8 h to further reduce the moisture content in the coriaria sinica and at the same time remove the moisture adsorbed on the surface of the coriaria sinica;

[0012] S6: Sample and conduct quality inspection on the coriaria sinica after the secondary completion. If the moisture content is less than 4% it is of high quality. Transfer the high-quality coriaria sinica to a vacuum packaging bag and conduct vacuum-sealed packaging and store it in the warehouse.

[0013] Furthermore, the ultrasonic frequency of the ultrasonic cleaning described in step S1 is 45 - 60 KHz, and the cleaning time is 5 - 10 min;

[0014] Furthermore, the thickness of the small pieces of coriaria sinica described in step S2 is 1.5 cm;

[0015] Furthermore, the temperature of the heating plate described in step S5 is 30 °C, and the temperature of the condenser is (-35) - (-45) °C; the temperature of the heating plate described in step S6 is 50 °C, and the temperature of the condenser is (-25) - (-30) °C.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows. The present invention prepares freeze-dried Coriaria nepalensis Wall. by means of multiple gradient freeze-drying. First, the moisture in Coriaria nepalensis Wall. is transformed into ice crystals, and at the same time, the generation of too large ice crystals can be avoided, so as to prevent the cells of Coriaria nepalensis Wall. from being damaged by too large ice crystals. Then, through primary freeze-drying, the ice crystals are quickly sublimated into gas to remove most of the moisture contained in Coriaria nepalensis Wall. Finally, through secondary freeze-drying, the moisture adsorbed on the surface of Coriaria nepalensis Wall. is sublimated into gas again to obtain freeze-dried Coriaria nepalensis Wall. with low moisture content and small loss of nutrients, which can best retain the natural color, aroma and flavor of Coriaria nepalensis Wall., and can retain the nutritional components of Coriaria nepalensis Wall. to the greatest extent. It is a very valuable food processing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flowchart of a preparation method of freeze-dried Coriaria nepalensis Wall. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] In order to make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments and drawings.

[0019] The experimental methods in the following embodiments are all conventional methods unless otherwise specified, and are carried out according to the technologies or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0020] Embodiment 1

[0021] 1: Transport the fresh Coriaria nepalensis Wall. raw materials to the unloading area in the factory, remove the damaged, rotten and overripe Coriaria nepalensis Wall., remove the fruit stalks, and then transfer them to an ultrasonic cleaner. Set the ultrasonic frequency to 45KHz and ultrasonically clean for 10 minutes to remove soil and impurities. Then send them to a foreign object detector to detect whether there are foreign objects;

[0022] 2: Cut the Coriaria nepalensis Wall. without detected foreign objects into small pieces with a thickness of 1.5 cm. After cutting, lay the small pieces of Coriaria nepalensis Wall. on a tray, and pay attention not to overlap the Coriaria nepalensis Wall. during the laying process;

[0023] 3: Turn on the cooling device of the quick-freezing warehouse to pre-freeze the Coriaria nepalensis Wall. Set the cooling rate of the cold warehouse to 8 °C / min, cool the cold warehouse to -10 °C, and keep it for 45 minutes. Then set the cooling rate of the cold warehouse to 6 °C / min, cool the cold warehouse to -18 °C, and keep it for 45 minutes. Then set the cooling rate to 10 °C to cool the cold warehouse to -40 °C, and keep it for 1.5 h;

[0024] 4: Transfer the pre-frozen Coriaria nepalensis Wall. to the freeze-drying chamber. At the same time, verify the sealing integrity of the chamber door to ensure the normal operation of the freeze-drying chamber. After verifying the complete sealing of the chamber door, turn on the vacuum pump and evacuate the freeze-drying chamber to a vacuum degree of 15 Pa. Maintain the vacuum degree at 15 Pa. Then turn on the heating plate of the freeze-drying chamber, set the temperature of the heating plate to 30 °C, set the temperature of the condenser to -45 °C, and keep the temperature of the Coriaria nepalensis Wall. at -26 °C for preliminary freeze-drying for 24 h to directly transform the solid ice into gas to remove the moisture inside the Coriaria nepalensis Wall.;

[0025] 5: After the preliminary freeze-drying is completed, adjust the vacuum degree to 40 Pa, set the temperature of the heating plate to 50 °C, set the temperature of the condenser to -30 °C, and keep the temperature of the Coriaria nepalensis Wall. at -18 °C for re-freeze-drying for 8 h to further reduce the moisture content in the Coriaria nepalensis Wall. and at the same time remove the moisture adsorbed on the surface of the Coriaria nepalensis Wall.;

[0026] 6: Sample the re-freeze-dried Coriaria nepalensis Wall. for quality inspection. If the moisture content is less than 4%, it is of high quality. Transfer the high-quality Coriaria nepalensis Wall. to a vacuum packaging bag, perform vacuum-sealed packaging and store it in the warehouse to obtain the freeze-dried Coriaria nepalensis Wall. prepared in Example 1.

[0027] Example 2

[0028] 1: Transport the fresh Coriaria nepalensis Wall. raw materials to the unloading area in the factory, remove the damaged, rotten and overripe Coriaria nepalensis Wall., remove the fruit stalks and then transfer them to an ultrasonic cleaner. Set the ultrasonic frequency to 60 KHz and perform ultrasonic cleaning for 5 min to remove soil and impurities. Then send them to a foreign object detector to detect whether there are foreign objects;

[0029] 2: Cut the Coriaria nepalensis Wall. that has been detected to have no foreign objects into small pieces with a length of and a thickness of 1.5 cm. After cutting, place the small pieces of Coriaria nepalensis Wall. on a tray, and pay attention not to stack the Coriaria nepalensis Wall. overlappingly during the tray placement process;

[0030] 3: Turn on the cooling device of the quick-freezing warehouse to pre-freeze the Coriaria nepalensis Wall. Set the cooling rate of the cold storage to 5 °C / min and cool the cold storage to -10 °C, and keep it for 30 min. Then set the cooling rate of the cold storage to 4 °C / min and cool the cold storage to -18 °C, and keep it for 30 min. Then set the cooling rate of the cold storage to 8 °C and cool the cold storage to -40 °C, and keep it for 1 h;

[0031] 4: Transfer the pre-frozen Coriaria nepalensis Wall. to the freeze-drying chamber. At the same time, verify the sealing integrity of the chamber door to ensure the normal operation of the freeze-drying chamber. After verifying the complete sealing of the chamber door, turn on the vacuum pump and evacuate the freeze-drying chamber to a vacuum degree of 10 Pa. Maintain the vacuum degree at 10 Pa. Then turn on the heating plate of the freeze-drying chamber, set the temperature of the heating plate to 30 °C, set the temperature of the condenser to -35 °C, and keep the temperature of the Coriaria nepalensis Wall. at -26 °C for preliminary freeze-drying for 18 h to directly transform the solid ice into gas to remove the moisture inside the Coriaria nepalensis Wall.;

[0032] 5: After the initial freeze-drying is completed, adjust the vacuum degree to 35 Pa, set the temperature of the heating plate to 50 °C, set the temperature of the condenser to -25 °C, keep the temperature of the Coriaria nepalensis Wall. at -18 °C and freeze-dry for another 6 h to further reduce the moisture content in the Coriaria nepalensis Wall. and remove the moisture adsorbed on the surface of the Coriaria nepalensis Wall.

[0033] 6: Sample the Coriaria nepalensis Wall. after the second freeze-drying is completed for quality inspection. If the moisture content is less than 4%, it is considered excellent. Transfer the high-quality Coriaria nepalensis Wall. to a vacuum packaging bag, seal it under vacuum and store it in the warehouse to obtain the freeze-dried Coriaria nepalensis Wall. prepared in Example 2.

[0034] Comparative Example 1

[0035] 1: Transport the fresh Coriaria nepalensis Wall. raw materials to the unloading area in the factory, remove the damaged, rotten and overripe Coriaria nepalensis Wall., remove the fruit stalks and transfer them to an ultrasonic cleaner. Set the ultrasonic frequency to 45 KHz and ultrasonically clean for 10 min to remove soil and impurities. Then send them to a foreign object detector to detect whether there are foreign objects.

[0036] 2: Cut the Coriaria nepalensis Wall. that has been detected to have no foreign objects into small pieces with a length and thickness of 1.5 cm. After cutting, lay the small pieces of Coriaria nepalensis Wall. on a tray, and pay attention not to overlap the Coriaria nepalensis Wall. during the laying process.

[0037] 3: Transfer the Coriaria nepalensis Wall. to the freeze-drying chamber. At the same time, verify the sealing integrity of the chamber door to ensure the normal operation of the freeze-drying chamber. After verifying the sealing integrity of the chamber door, turn on the vacuum pump, pump the freeze-drying chamber to a vacuum degree of 15 Pa, maintain the vacuum degree at 15 Pa, then turn on the heating plate of the freeze-drying chamber, set the temperature of the heating plate to 30 °C, set the temperature of the condenser to -45 °C, and keep the temperature of the Coriaria nepalensis Wall. at -26 °C for initial freeze-drying for 24 h.

[0038] 4: After the initial freeze-drying is completed, adjust the vacuum degree to 40 Pa, set the temperature of the heating plate to 50 °C, set the temperature of the condenser to -30 °C, keep the temperature of the Coriaria nepalensis Wall. at -18 °C and freeze-dry for another 8 h. After the second freeze-drying is completed, transfer the Coriaria nepalensis Wall. to a vacuum packaging bag, seal it under vacuum and store it in the warehouse to obtain the freeze-dried Coriaria nepalensis Wall. prepared in Comparative Example 1.

[0039] Comparative Example 2

[0040] 1: Transport the fresh Coriaria nepalensis Wall. raw materials to the unloading area in the factory, remove the damaged, rotten and overripe Coriaria nepalensis Wall., remove the fruit stalks and transfer them to an ultrasonic cleaner. Set the ultrasonic frequency to 60 KHz and ultrasonically clean for 5 min to remove soil and impurities. Then send them to a foreign object detector to detect whether there are foreign objects.

[0041] 2: Cut the Coriaria nepalensis Wall. that has been detected to have no foreign objects into small pieces with a length of 1.5 cm. After cutting, lay the small pieces of Coriaria nepalensis Wall. on a tray, and pay attention not to overlap the Coriaria nepalensis Wall. during the laying process.

[0042] 3: Verify the integrity of the chamber door seal to ensure the normal operation of the freeze-drying chamber. After verifying the integrity of the chamber door seal, turn on the vacuum pump and evacuate the freeze-drying chamber to a vacuum degree of 10 Pa. Maintain the vacuum degree at 10 Pa, then turn on the heating plate of the freeze-drying chamber, set the temperature of the heating plate to 30 °C, set the temperature of the condenser to -35 °C, keep the temperature of the Coriaria nepalensis Wall. at -26 °C for freeze-drying for 18 h. After the freeze-drying is completed, transfer the Coriaria nepalensis Wall. to a vacuum packaging bag, perform vacuum-sealed packaging and store it in the warehouse to obtain the freeze-dried Coriaria nepalensis Wall. prepared in Comparative Example 2.

[0043] Nutritional index detection

[0044] Perform nutritional index detection on the freeze-dried Coriaria nepalensis Wall. prepared in Examples 1-2 and Comparative Examples 1-2 in accordance with the regulations in GB / T 5009.245-2016 "National Food Safety Standard - Determination of Nutritional Components in Foods - Part 245: Freeze-Dried Foods".

[0045] Table 1. Nutritional detection results

[0046]

[0047] Sensory and physical-chemical index tests

[0048] Determine the sensory requirements and physical-chemical indexes of the freeze-dried Coriaria nepalensis Wall. prepared in Examples 1-2 and Comparative Examples 1-2 in accordance with the standard of GB / T 14488-2015 "Methods for Sensory Evaluation of Foods".

[0049] Table 2. Sensory test results

[0050]

[0051] Table 3. Physical-chemical index detection results

[0052]

[0053] It can be seen from the analysis of Tables 1-3 that compared with Comparative Examples 1-2, the freeze-dried Coriaria nepalensis Wall. prepared in Examples 1-2 has less loss of nutritional components, a low moisture content, and at the same time, it has a complete form, no fragmentation, and a good taste during the freeze-drying process; it is suitable for long-term storage.

[0054] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of freeze-dried Coriaria nepalensis Wall., characterized in that, It includes the following steps: S1: Deliver the fresh Coriaria nepalensis Wall. raw materials to the in-plant unloading area, remove the damaged, rotten and overripe Coriaria nepalensis Wall., remove the fruit stalks and then transfer them to an ultrasonic cleaner for ultrasonic cleaning to remove soil and impurities; S2: After ultrasonic cleaning, cut the Coriaria nepalensis Wall. into small pieces. After cutting, lay the small pieces of Coriaria nepalensis Wall. on a tray. During the tray-laying process, pay attention not to overlap the Coriaria nepalensis Wall.; S3: Turn on the cooling device of the quick-freezing storage to pre-freeze the Coriaria nepalensis Wall. Set the cooling rate of the cold storage to 5 - 8 °C / min and cool the cold storage to -10 °C, and keep it for 30 - 45 min. Then set the cooling rate of the cold storage to 4 - 6 °C / min and cool the cold storage to -18 °C, and keep it for 30 - 45 min. Then set the cooling rate of the cold storage to 8 - 10 °C and cool the cold storage to -40 °C, and keep it for 1 - 1.5 h; S4: Transfer the Coriaria nepalensis Wall. to the freeze-drying chamber. At the same time, verify the sealing integrity of the chamber door to ensure the normal operation of the freeze-drying chamber. After verifying the sealing integrity of the chamber door, turn on the vacuum pump and pump the freeze-drying chamber to a vacuum degree of 10 - 15 Pa, and maintain the vacuum degree of 10 - 15 Pa. Then turn on the heating plate and condenser of the freeze-drying chamber, keep the temperature of the Coriaria nepalensis Wall. at -26 °C for preliminary freeze-drying for 10 - 12 h to directly convert the solid ice into gas to remove the moisture in the Coriaria nepalensis Wall.; S5: After preliminary freeze-drying, adjust the vacuum degree to 35 - 40 Pa, adjust the temperature of the heating plate and condenser of the freeze-drying chamber, keep the temperature of the Coriaria nepalensis Wall. at -18 °C for re-freeze-drying for 6 - 8 h to further reduce the moisture content in the Coriaria nepalensis Wall. and at the same time remove the moisture adsorbed on the surface of the Coriaria nepalensis Wall.; S6: Sample the re-completed Coriaria nepalensis Wall. for quality inspection. If the moisture content is less than 4%, it is of high quality. Transfer the high-quality Coriaria nepalensis Wall. to a vacuum packaging bag and conduct vacuum-sealed packaging and store it in the warehouse.

2. The preparation method of freeze-dried Coriaria nepalensis Wall. according to claim 1, characterized in that, The ultrasonic frequency of the ultrasonic cleaning described in step S1 is 45 - 60 KHz, and the cleaning time is 5 - 10 min.

3. The preparation method of freeze-dried Coriaria nepalensis Wall. according to claim 1, wherein, The thickness of the small pieces of Coriaria nepalensis Wall. described in step S2 is 1.5 cm.

4. The preparation method of freeze-dried Coriaria nepalensis Wall. according to claim 1, characterized in that, The temperature of the heating plate described in step S5 is 30 °C, and the temperature of the condenser is (-35) - (-45) °C.

5. The preparation method of freeze-dried Coriaria nepalensis Wall. according to claim 1, characterized in that, The temperature of the heating plate described in step S6 is 50 °C, and the temperature of the condenser is (-25) - (-30) °C.

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