Preparation process of rumex hanus freeze-dried powder
By optimizing the freeze-drying process of edible leaf grass powder, the problems of nutrient loss and preservation have been solved, achieving high efficiency in preservation and long-term stability, thus ensuring the nutritional value and quality of the product.
Patent Information
- Application Number
- CN202511769683.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-01-16
AI Technical Summary
Existing processing methods for leafy greens result in significant loss of nutrients, poor product quality, and difficulty in long-term preservation.
Optimized raw material processing, freeze-drying, and post-processing techniques are employed, including rapid freezing, vacuum drying, drying under low-temperature and low-oxygen conditions, ultra-fine pulverization, and high-barrier packaging, to ensure the retention of nutrients and product stability.
It achieves efficient preservation of nutrients in freeze-dried leafy green powder, with a bright green color, good rehydration properties, long shelf life, no additives, and high product stability.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of agricultural product deep processing technology, specifically referring to a preparation process of freeze-dried leafy grass powder. Background Technology
[0002] Edible leaf grass is a type of herbaceous plant rich in protein, vitamins, minerals, and various bioactive components, possessing extremely high nutritional value and development potential. However, fresh edible leaf grass has a high water content, is prone to rotting and spoilage, and has a strong seasonal supply, making it difficult to preserve for long periods after harvesting, which limits its industrial development.
[0003] Currently, the main processing methods for leafy greens include traditional drying techniques such as sun drying and hot air drying. Although these methods are low-cost, the high processing temperature and long processing time can lead to the destruction and loss of a large number of heat-sensitive nutrients. At the same time, they can easily cause the leaves to turn yellow or brown, resulting in poor product quality, poor rehydration, and low bioavailability.
[0004] While freeze-drying technology can theoretically solve the aforementioned problems, improper control of process parameters can still lead to issues such as excessive energy consumption, incomplete drying, color deterioration, or unsatisfactory retention of nutrients. For example, if enzymes are not effectively inactivated during pretreatment, enzymes such as polyphenol oxidase will still slowly act and cause discoloration even during freeze-drying; improper blanching can result in a significant loss of water-soluble nutrients; and poor control of freezing rate and vacuum can cause ice crystals to pierce cell walls, affecting product structure and rehydration properties. Therefore, a novel process for preparing freeze-dried leafy green powder addresses these challenges. Summary of the Invention
[0005] To address the aforementioned existing problems, this invention provides a process for preparing freeze-dried edible grass powder that optimizes key steps such as raw material processing, color protection and sterilization, freeze-drying, and post-processing to achieve efficient retention of nutrients in edible grass, resulting in freeze-dried powder with high nutrient retention rate, bright green color, good solubility, and easy storage.
[0006] The technical solution adopted in this invention is as follows: The preparation process of the freeze-dried leafy green powder of this invention includes the following steps:
[0007] S1, Preprocessing
[0008] S1.1 Raw material selection and harvesting: Select fresh, bright green, leafy grasses that are in the vegetative growth stage, free from yellow leaves, pests and diseases, and rot.
[0009] S1.2 Cleaning and impurity removal: Rinse with running clean water to remove surface mud, dust and some microorganisms. Then use a bubble cleaner to thoroughly remove impurities from leaf folds and stem crevices through the rolling and impact of bubbles. Finally, rinse with pure water to ensure cleanliness.
[0010] S1.3 Draining: Place the washed leafy grass on a clean sieve to drain naturally;
[0011] S1.4 Color protection and sterilization: Immerse the leafy grass in hot water at 90-95℃ for ten seconds, and then immediately cool it down with ice water or cold water.
[0012] S2, freeze drying
[0013] S2.1 Loading and quick-freezing: Spread the processed leafy grass evenly on the material tray of the freeze dryer, send the tray into the freeze drying chamber, start the equipment for quick freezing, and the quick freezing temperature is -30℃ to -40℃.
[0014] S2.2 Vacuum freeze drying: After the material is completely frozen, start the vacuum pump to evacuate the drying chamber to a high vacuum state, where the pressure is below 100Pa.
[0015] S2.3 Sublimation Drying: Under vacuum conditions, the shelf is slowly heated so that the ice crystals in the material directly sublimate from solid to water vapor.
[0016] S2.4, Analysis and Drying: Continue to increase the shelf temperature and extend the drying time to remove bound water that is combined with the material molecules;
[0017] S2.5 Discharge and Inspection: After drying, release the vacuum, take out the material and test its moisture content. Qualified freeze-dried products have a moisture content of less than 5%.
[0018] S3, Post-processing and Packaging
[0019] S3.1, Coarse grinding: The crisp freeze-dried leafy grass blocks are initially ground to obtain coarser particles;
[0020] S3.2, Ultrafine grinding: Using an ultrafine grinder to grind coarse particles into ultrafine powder;
[0021] S3.3, Sieving: Pass the ultrafine powder through a sieve with a mesh size of 200 or higher;
[0022] S3.4 Metal Detection and Sterilization: Use a metal detector to ensure that there are no metal impurities in the product, and then perform low-temperature terminal sterilization treatment such as irradiation or ultraviolet light.
[0023] S3.5 Packaging and Storage: Use high-barrier packaging materials such as aluminum foil bags or aluminized film bags. Vacuum-pack and fill with nitrogen before sealing. After sealing, place in a cardboard box and store in a cool, dry, and dark place.
[0024] Preferably, step S1 further includes cutting and crushing: the whole plant or leaves are cut or crushed as needed to increase the surface area, speed up the freezing and drying process, and make the finished powder more uniform.
[0025] Preferably, step S1.3 is surface dehydration: using a centrifugal dehydrator for light dehydration to remove excess surface moisture, thereby shortening the subsequent freeze-drying time and saving energy.
[0026] Preferably, steps S2.2, S2.3, and S2.4 are carried out in a low-temperature, low-oxygen environment, which effectively avoids the destruction and oxidation of heat-sensitive nutrients.
[0027] The beneficial effects achieved by the present invention using the above structure are as follows:
[0028] 1. Maximize nutrient retention: Low-temperature processing maximizes the retention of heat-sensitive components such as protein, vitamins, chlorophyll, and SOD.
[0029] 2. Excellent color and shape: It retains the natural green color of edible leaves and has good rehydration properties.
[0030] 3. No additives: No preservatives are required throughout the entire process.
[0031] 4. Long shelf life: The extremely low moisture content and vacuum nitrogen-filled packaging result in extremely high product stability and a long shelf life. Detailed Implementation
[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0033] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0035] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.
[0036] The preparation process of freeze-dried leafy green powder proposed in this scheme includes the following steps:
[0037] S1, Preprocessing
[0038] S1.1 Raw material selection and harvesting: Select fresh, bright green, leafy grasses that are in the vegetative growth stage, free from yellow leaves, pests and diseases, and rot.
[0039] S1.2 Cleaning and impurity removal: Rinse with running clean water, then use a bubble cleaner, and finally rinse with purified water.
[0040] S1.3 Draining: Place the washed leafy grass on a clean sieve to drain naturally;
[0041] S1.4 Color protection and sterilization: Immerse the leafy grass in hot water at 90-95℃ for ten seconds, and then immediately cool it down with ice water or cold water.
[0042] S2, freeze drying
[0043] S2.1 Loading and quick-freezing: Spread the processed leafy grass evenly on the material tray of the freeze dryer, send the tray into the freeze drying chamber, start the equipment for quick freezing, and the quick freezing temperature is -30℃ to -40℃.
[0044] S2.2 Vacuum freeze drying: After the material is completely frozen, start the vacuum pump to evacuate the drying chamber to a high vacuum state, where the pressure is below 100Pa.
[0045] S2.3 Sublimation Drying: Under vacuum conditions, the shelf is slowly heated so that the ice crystals in the material directly sublimate from solid to water vapor.
[0046] S2.4, Analysis and Drying: Continue to increase the shelf temperature and extend the drying time to remove bound water that is combined with the material molecules;
[0047] S2.5 Discharge and Inspection: After drying, release the vacuum, take out the material and test its moisture content. Qualified freeze-dried products have a moisture content of less than 5%.
[0048] S3, Post-processing and Packaging
[0049] S3.1, Coarse grinding: The crisp freeze-dried leafy grass blocks are initially ground to obtain coarser particles;
[0050] S3.2, Ultrafine grinding: Using an ultrafine grinder to grind coarse particles into ultrafine powder;
[0051] S3.3, Sieving: Pass the ultrafine powder through a sieve with a mesh size of 200 or higher;
[0052] S3.4 Metal Detection and Sterilization: Use a metal detector to ensure that there are no metal impurities in the product, and then perform low-temperature terminal sterilization treatment such as irradiation or ultraviolet light.
[0053] S3.5 Packaging and Storage: Use high-barrier packaging materials such as aluminum foil bags or aluminized film bags. Vacuum-pack and fill with nitrogen before sealing. After sealing, place in a cardboard box and store in a cool, dry, and dark place.
[0054] Step S1 further includes cutting and crushing: the whole plant or leaves are cut or crushed as needed to increase the surface area, speed up the freezing and drying process, and make the finished powder more uniform.
[0055] Step S1.3 is surface dehydration: a centrifugal dehydrator is used for light dehydration to remove excess water from the surface, thereby shortening the subsequent freeze-drying time and saving energy.
[0056] Steps S2.2, S2.3, and S2.4 are carried out in a low-temperature, low-oxygen environment, which effectively avoids the destruction and oxidation of heat-sensitive nutrients.
[0057] Example 1: The preparation process of freeze-dried leafwort powder includes the following steps:
[0058] S1, Preprocessing
[0059] S1.1 Raw material selection and harvesting: Select fresh, bright green, disease-free, pest-free, and rot-free leafy grasses in the vegetative growth stage for harvesting. Leafy grasses in the vegetative growth stage have the highest protein and nutrient content. After harvesting, they should be put into the processing process as soon as possible to avoid piling up and generating heat.
[0060] S1.2 Cleaning and impurity removal: Rinse with running clean water to remove surface mud, dust and some microorganisms. Then use a bubble cleaner to thoroughly remove impurities from leaf folds and stem crevices through the rolling and impact of bubbles. Finally, rinse with pure water to ensure cleanliness.
[0061] S1.3 Draining: Place the washed leafy grass on a clean sieve to drain naturally;
[0062] S1.4 Color protection and sterilization: Blanch the leafy grass in hot water at 90-95℃ for ten seconds to kill the putrefactive microorganisms and enzymes on the surface, destroy chlorophyllase and polyphenol oxidase, etc., to prevent the color from turning yellow or brown during processing and storage, and reduce the loss of water-soluble vitamins and other nutrients. After blanching, immediately cool it with ice water or cold water to terminate the heat processing.
[0063] S2, freeze drying
[0064] S2.1, Loading and quick-freezing: Spread the processed leafy grass evenly on the material tray of the freeze dryer, send the tray into the freeze drying chamber, start the equipment for quick freezing, the temperature of quick freezing is -30℃ to -40℃, quick freezing prevents the cell wall from being pierced by large ice crystals and maintains the material structure;
[0065] S2.2 Vacuum freeze drying: After the material is completely frozen, start the vacuum pump to evacuate the drying chamber to a high vacuum state, where the pressure is below 100Pa.
[0066] S2.3 Sublimation Drying: Under vacuum conditions, the shelves are slowly heated to provide the heat required for the sublimation of ice crystals. The ice crystals in the material do not pass through a liquid state, but directly sublimate from a solid state to water vapor;
[0067] S2.4, Analysis and Drying: After the free water is removed, the shelf temperature is increased and the drying time is extended to remove the bound water that is combined with the material molecules.
[0068] Vacuum freeze drying, sublimation drying, and desorption drying are all carried out in a low-temperature and low-oxygen environment, which effectively avoids the damage and oxidation of heat-sensitive nutrients.
[0069] S2.5 Discharge and Inspection: After drying, the vacuum is released. At this time, the shape of the leafy grass remains unchanged, but the texture becomes very brittle and can be crushed with a pinch. The material is taken out and its moisture content is tested. The moisture content of qualified freeze-dried products is less than 5%.
[0070] S3, Post-processing and Packaging
[0071] S3.1, Coarse grinding: The crisp freeze-dried leafy grass blocks are initially ground to obtain coarser particles;
[0072] S3.2, Ultrafine grinding: Using an ultrafine grinder to grind coarse particles into ultrafine powder increases the specific surface area, improves the solubility and bioavailability of nutrients, and results in a more delicate taste;
[0073] S3.3 Sieving: Pass the ultrafine powder through a sieve of 200 mesh or higher to ensure uniform powder fineness and remove coarse fibers or lumps;
[0074] S3.4 Metal Detection and Sterilization: Use a metal detector to ensure that there are no metal impurities in the product, and then perform low-temperature terminal sterilization treatment such as irradiation or ultraviolet light.
[0075] S3.5 Packaging and Storage: Use high-barrier packaging materials such as aluminum foil bags or aluminized film bags. Vacuum and fill with nitrogen before sealing to delay oxidation and maintain product quality. After sealing, put it in a carton and store it in a cool, dry, and dark place.
[0076] Example 2: The preparation process of freeze-dried leafwort powder includes the following steps:
[0077] S1, Preprocessing
[0078] S1.1 Raw material selection and harvesting: Select fresh, bright green, disease-free, pest-free, and rot-free leafy grasses in the vegetative growth stage for harvesting. Leafy grasses in the vegetative growth stage have the highest protein and nutrient content. After harvesting, they should be put into the processing process as soon as possible to avoid piling up and generating heat.
[0079] S1.2 Cleaning and impurity removal: Rinse with running clean water to remove surface mud, dust and some microorganisms. Then use a bubble cleaner to thoroughly remove impurities from leaf folds and stem crevices through the rolling and impact of bubbles. Finally, rinse with pure water to ensure cleanliness.
[0080] S1.3 Draining: Use a centrifugal dehydrator for light dehydration to remove excess surface moisture, thereby shortening the subsequent freeze-drying time and saving energy.
[0081] S1.4 Cutting and Crushing: Cut or crush the whole plant or leaves into appropriate segments as needed to increase the surface area, speed up the freezing and drying process, and make the finished powder more uniform.
[0082] S1.5 Color protection and sterilization: Blanch the leafy grass in hot water at 90-95℃ for ten seconds to kill the decaying microorganisms and enzymes on the surface, destroy chlorophyllase and polyphenol oxidase, etc., to prevent the color from turning yellow or brown during processing and storage, and reduce the loss of water-soluble vitamins and other nutrients. After blanching, immediately cool it with ice water or cold water to terminate the heat processing.
[0083] S2, freeze drying
[0084] S2.1, Loading and quick-freezing: Spread the processed leafy grass evenly on the material tray of the freeze dryer, send the tray into the freeze drying chamber, start the equipment for quick freezing, the temperature of quick freezing is -30℃ to -40℃, quick freezing prevents the cell wall from being pierced by large ice crystals and maintains the material structure;
[0085] S2.2 Vacuum freeze drying: After the material is completely frozen, start the vacuum pump to evacuate the drying chamber to a high vacuum state, where the pressure is below 100Pa.
[0086] S2.3 Sublimation Drying: Under vacuum conditions, the shelves are slowly heated to provide the heat required for the sublimation of ice crystals. The ice crystals in the material do not pass through a liquid state, but directly sublimate from a solid state to water vapor;
[0087] S2.4, Analysis and Drying: After the free water is removed, the shelf temperature is increased and the drying time is extended to remove the bound water that is combined with the material molecules.
[0088] Vacuum freeze drying, sublimation drying, and desorption drying are all carried out in a low-temperature and low-oxygen environment, which effectively avoids the damage and oxidation of heat-sensitive nutrients.
[0089] S2.5 Discharge and Inspection: After drying, the vacuum is released. At this time, the shape of the leafy grass remains unchanged, but the texture becomes very brittle and can be crushed with a pinch. The material is taken out and its moisture content is tested. The moisture content of qualified freeze-dried products is less than 5%.
[0090] S3, Post-processing and Packaging
[0091] S3.1, Coarse grinding: The crisp freeze-dried leafy grass blocks are initially ground to obtain coarser particles;
[0092] S3.2, Ultrafine grinding: Using an ultrafine grinder to grind coarse particles into ultrafine powder increases the specific surface area, improves the solubility and bioavailability of nutrients, and results in a more delicate taste;
[0093] S3.3 Sieving: Pass the ultrafine powder through a sieve of 200 mesh or higher to ensure uniform powder fineness and remove coarse fibers or lumps;
[0094] S3.4 Metal Detection and Sterilization: Use a metal detector to ensure that there are no metal impurities in the product, and then perform low-temperature terminal sterilization treatment such as irradiation or ultraviolet light.
[0095] S3.5 Packaging and Storage: Use high-barrier packaging materials such as aluminum foil bags or aluminized film bags. Vacuum and fill with nitrogen before sealing to delay oxidation and maintain product quality. After sealing, put it in a carton and store it in a cool, dry, and dark place.
[0096] The embodiments described above are preferred embodiments of the present invention, but not all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
Claims
1. A process for the preparation of a freeze-dried powder of Cenchrus ciliaris, characterized in that, It comprises the following steps: S1, pretreatment S1.1, raw material selection and harvesting: select fresh, jade green, no yellow leaves, no disease and insect pests, no rotten food leaves for harvesting; S1.2, cleaning and removing impurities: rinse with flowing clean water, then use a bubble cleaning machine, and finally rinse with pure water; S1.3, draining: place the cleaned food leaves on a clean screen to drain naturally; S1.4, color protection and sterilization: immerse the food leaves in hot water at 90-95℃ for blanching for ten seconds, and then quickly cool with ice water or cold water; S2, freeze-drying S2.1, tray and quick freezing: evenly spread the treated food leaves on the material tray of the freeze dryer, put the tray into the freeze-drying chamber, and start the equipment for quick freezing; S2.2, vacuum freeze-drying: when the material is completely frozen, start the vacuum pump to draw the drying chamber to a high vacuum state; S2.3, sublimation drying: slowly heat the shelves in a vacuum environment, so that the ice crystals in the material directly sublimate into water vapor; S2.4, desorption drying: continue to increase the shelf temperature and extend the drying time to remove the bound water combined with the material molecules; S2.5, discharging and testing: after drying, release the vacuum, take out the material and test its water content, and the qualified freeze-dried product has a water content of less than 5%; S3, post-processing and packaging S3.1, coarse crushing: coarsely crush the crisp freeze-dried food leaves to obtain relatively coarse particles; S3.2, ultrafine grinding: use an ultrafine grinder to grind the coarse particles into ultrafine powder; S3.3, sieving: pass the ultrafine powder through a sieve with a mesh size of more than 200; S3.4, metal detection and sterilization: use a metal detector to ensure that there is no metal impurity in the product, and then perform low-temperature terminal sterilization treatment such as irradiation or ultraviolet light; S3.5, packaging and storage: use packaging materials with high barrier properties such as aluminum foil bags or aluminum-coated film bags, vacuumize before sealing and fill with nitrogen; after sealing, put it into a carton and store it in a cool, dry and light-proof place.
2. The process for preparing a freeze-dried powder of Urena lobata according to claim 1, characterized by the fact that: The food leaf harvesting period in step S1 is selected during the vegetative growth period, when the protein and nutrient content is highest.
3. The process for preparing a freeze-dried powder of Urena lobata L. according to claim 1, characterized by the fact that: The step S1 also includes cutting and breaking: cutting or breaking the whole plant or leaves as needed.
4. The process for preparing a freeze-dried powder of Urena lobata according to claim 1, characterized by the fact that: The step S1.3 is surface dehydration: use a centrifugal dehydrator for light dehydration to remove excess surface moisture.
5. The process for preparing a freeze-dried powder of Urena lobata according to claim 1, characterized by the fact that: The temperature of the quick freezing is -30℃ to -40℃.
6. The process for preparing a freeze-dried powder of Urena lobata according to claim 1, characterized by the fact that: The high vacuum state in step S2.2 has a pressure lower than 100Pa.
7. The process for preparing a freeze-dried powder of Urena lobata according to claim 1, characterized by the fact that: Steps S2.2, S2.3 and S2.4 are carried out in a low-temperature, low-oxygen environment.