Continuous extraction process of jujube tincture in jujube peel

Abstract

The application provides a process for continuously extracting jujube tincture from jujube peel, and specifically comprises the following steps: continuously conveying jujube raw materials to the feeding port of a U-shaped extraction tower preloaded with an ethanol solution of a specific concentration, and continuously feeding ethanol of a corresponding concentration into the extraction agent inlet of the extraction tower. Under the action of a spiral mixing propeller, the jujube and the ethanol solution form countercurrent motion in the tower, and through continuous countercurrent contact, mass transfer and extraction of target components are achieved. During the extraction process, the extraction liquid containing jujube tincture and the discarded jujube residues are continuously discharged from the system; after the obtained extraction liquid is subjected to vacuum distillation and cooling treatment, jujube tincture products are obtained. The application has the advantages that: the extraction tower structure adopted is compact, easy to operate, and easy to realize automatic control; in particular, the solvent consumption can be significantly reduced during the extraction process of jujube tincture, the extraction time is shortened, the concentration of target components in the extraction liquid is increased, and the overall energy consumption is effectively reduced.

Description

[0001] Technical Field: This invention relates to the field of biotechnology, specifically to a continuous extraction process for jujube tincture from jujube peel. Background Technology

[0002] Red dates are rich in various nutrients and health-promoting components, and are widely used in food, food additives, and tobacco flavorings. Red date tincture is a brownish-red liquid obtained through alcohol extraction from red dates. The aroma components are typically more abundant in the date skin than in the flesh. This product has the unique fragrance and sweetness of red dates, and its main components include monosaccharides, vitamin C, organic acids, and esters. As a natural flavoring agent, red date tincture can effectively mask off-flavors and reduce the irritation of tobacco products with its unique date aroma, thus finding wide application in cigarette flavoring and the food and beverage industries.

[0003] Currently, the main extraction methods for jujube tincture include solvent extraction, ultrasonic extraction, and supercritical fluid extraction. While ultrasonic extraction and supercritical fluid extraction help improve extraction efficiency, they have not yet become mainstream due to high equipment investment and limitations in large-scale production. Solvent extraction remains the most widely used extraction method in China, but it typically employs multi-stage extraction tanks for intermittent operation. In this method, the solid material remains stationary during extraction, the solvent is added all at once, and the extract and solid residue are discharged in batches only after extraction is complete. If multi-stage cross-flow extraction is used, the extract must be separated after each extraction, and the solvent must be replenished for repeated extraction until the predetermined number of extractions is reached. Finally, the extract is separated, unloaded, and re-feeded. This process suffers from problems such as high solvent consumption, cumbersome operation steps, high energy consumption, long production cycle, and limited extraction efficiency. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a continuous extraction process for jujube tincture from jujube peel, aiming to reduce the amount of extraction solvent used, shorten the extraction time, increase the concentration of jujube tincture in the extract, and effectively reduce overall energy consumption. This method is simple to operate and suitable for large-scale industrial production.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] Step 1) Raw material processing: Select fresh red dates with thick skin, and clean and polish them.

[0007] Step 2) Feeding preparation: Place the processed jujubes into the jujube feeding tank, and equip the tank outlet with a screw feeder;

[0008] Step 3) Preparation of extractant: In the extractant storage tank, prepare an ethanol solution with a concentration of 60%–90% using food-grade ethanol and water, and heat it to 40–60°C.

[0009] Step 4) Preparation of the extraction tower: Debug the U-shaped cylindrical extraction tower and fill the tower with the ethanol solution obtained in step 3); the extraction tower is equipped with a jujube inlet and an extractant inlet and outlet at both ends, and a spiral mixing propeller is installed inside the tower. Its blades have openings and are covered with a filter screen, which can make the extract flow in reverse and effectively retain solid materials.

[0010] Step 5) Continuous feeding and countercurrent control: The jujubes from Step 2) and the ethanol solution from Step 3) are continuously fed into the extraction tower at a volume ratio of 1:2–1:6. By adjusting the feed flow rate and the screw propeller speed, continuous countercurrent contact between the jujubes and ethanol is achieved. Step 6) Mass transfer extraction and condition control: Mass transfer extraction of jujube tincture is completed during the continuous countercurrent contact process. By optimizing the solid-liquid ratio, screw propeller speed, and extraction temperature, precise control of the extraction process is achieved.

[0011] Step 7) Material separation: The extract containing jujube tincture and the waste jujubes are continuously discharged through the corresponding outlets of the extraction tower; Step 8) Extract sedimentation: The obtained extract is allowed to settle naturally in the storage tank for 2–6 hours;

[0012] Step 9) Concentration and solvent recovery: The supernatant after sedimentation is sent to an ethanol vacuum concentration and recovery device for vacuum concentration at 50–60℃ and a vacuum degree of 0.04–0.08MPa to obtain jujube tincture paste. At the same time, gaseous ethanol is recovered and collected by a condenser. Step 10) Product testing: The appearance, odor, sugar content and ethanol residue of the obtained jujube tincture paste are tested.

[0013] The beneficial effects of this invention are as follows: It provides a continuous extraction process for jujube tincture from jujube peel. This continuous operation avoids the repeated loading and unloading of materials and multiple heating of the solvent in traditional batch processes, significantly shortening the production cycle and improving processing efficiency. The extraction tower has a compact structure and is easy to operate, helping to reduce labor intensity. The overall process has outstanding advantages such as large processing capacity, low energy consumption, short processing time, and ease of automation. Furthermore, this technology can also be extended to the extraction of active ingredients from other solid raw materials such as mycelium and plant materials. Attached Figure Description

[0014] Figure 1Flowchart of continuous countercurrent extraction process for jujube tincture. Jujube raw material is continuously fed into the extraction tower from the feed tank (1) via a solid transfer pump through the solid phase inlet; simultaneously, ethanol solution of a set concentration in the solvent tank (3) is continuously injected into the tower via a metering pump through the solvent inlet. Under the action of the spiral mixing propeller, jujube and ethanol are fully mixed and undergo mass transfer in the tower, so that the jujube tincture in the jujube skin is effectively dissolved in the ethanol. The propeller continuously pushes the extracted jujube to the storage tank (2) connected to the solid phase outlet; the ethanol solution containing jujube tincture flows out countercurrently through the openings on the propeller blades and the filter screen, and enters the storage tank (4) connected to the solvent outlet. The extraction temperature is jointly controlled by the solvent tank (3) and the heating tank (5). The hot water provided in the heating tank (5) enters the heating jacket of the extraction tower for circulation, so as to achieve stable regulation of the temperature inside the tower. Detailed Implementation

[0015] Example 1

[0016] 1) Select fresh, thick-skinned red dates, wash and polish them, then place them in the date feed tank. Prepare an 80% ethanol solution in the extractant storage tank and heat it to 40℃ for later use. Test the extraction tower by filling it with the 80% ethanol solution and circulating 40℃ water through the tower jacket to maintain the system temperature. Then, continuously feed the red dates into the extraction tower from the material inlet using a solids transfer pump, while simultaneously continuously pumping the 80% ethanol solution from the storage tank into the extraction tower via a metering pump; set the volumetric feed ratio of red dates to ethanol solution to 1:6.

[0017] 2) Adjust the screw propeller speed to 20 rpm to ensure stable countercurrent continuous contact between the jujubes and ethanol within the tower. The propeller blades are equipped with micropores and covered with a filter screen, which promotes countercurrent flow of the extract during mixing and effectively traps solid materials. A double-helix structure is used at the bends of the extraction tower to prevent solid material accumulation and blockage. After extraction, the extract containing jujube tincture flows out through the filter screen and extract outlet, while the solid material is pushed to the material outlet, where it is squeezed out by a compression device to remove residual extract before being continuously discharged.

[0018] 3) The obtained extract was allowed to settle naturally in a storage tank for 6 hours. The supernatant was then placed in an ethanol vacuum concentration and recovery device and concentrated under vacuum at 55°C and 0.06 MPa to obtain jujube tincture. The volatilized gaseous ethanol was recovered and collected by a condenser.

[0019] 4) The jujube tincture prepared in this embodiment is a reddish-brown clear viscous liquid with a typical sweet jujube aroma, an ethanol content of 18.2%, and a sugar content of 40.7%.

[0020] Example 2

[0021] 1) Select fresh, thick-skinned red dates, wash and polish them, then place them in a date feed tank for later use. Prepare a 70% ethanol solution in the extractant storage tank and heat it to 70℃. Test the extraction tower system, pre-charge the tower with 80% ethanol solution until full, and circulate 70℃ hot water through the extraction tower jacket to maintain a constant operating temperature. Subsequently, continuously feed the red dates into the extraction tower from the material inlet using a solids transfer pump, while simultaneously continuously pumping the 70% ethanol solution from the storage tank into the extraction tower using a metering pump; control the volume ratio of red dates to ethanol solution to be 1:4.

[0022] 2) Adjust the screw propeller speed to 40 rpm to ensure stable countercurrent contact between the jujubes and ethanol within the tower. The propeller blades are equipped with micropores and covered with a filter screen, enabling countercurrent liquid-solid flow and effective separation during mixing. A double-screw device is installed in the turning section of the extraction tower to prevent solid material blockage. During extraction, the extract flows continuously out through the micropores of the blades and the filter screen to the extract outlet; the extracted solid material is pushed to the material outlet, where it is compressed to remove residual liquid before being continuously discharged from the system.

[0023] 3) The obtained extract containing jujube tincture was allowed to stand and settle in a storage tank for 6 hours. The supernatant was then introduced into an ethanol vacuum concentration and recovery device and concentrated under reduced pressure at 50°C and 0.06 MPa to obtain jujube tincture paste. The volatilized gaseous ethanol was recovered and collected by a condenser.

[0024] 4) The jujube tincture prepared in this embodiment is a clear, viscous, reddish-brown color with a typical sweet jujube flavor. Its ethanol content is 17.6% and its sugar content is 39.4%.

[0025] Example 3

[0026] 1) Select fresh, thick-skinned red dates, wash and polish them, then place them in the date feed tank. Prepare a 60% ethanol solution in the extractant storage tank and heat it to 60℃ for later use. Test the extraction tower by filling it with the 60% ethanol solution and circulating 60℃ water through the tower jacket to maintain the system temperature. Then, continuously feed the red dates into the extraction tower from the material inlet using a solids transfer pump, while simultaneously continuously pumping the 60% ethanol solution from the storage tank into the extraction tower via a metering pump; set the volumetric feed ratio of red dates to ethanol solution to 1:2.

[0027] 2) Adjust the screw propeller speed to 60 rpm to ensure stable countercurrent continuous contact between the jujubes and ethanol within the tower. The propeller blades are equipped with micropores and covered with a filter screen, which promotes countercurrent flow of the extract during mixing and effectively traps solid materials. A double-helix structure is used at the bends of the extraction tower to prevent solid material accumulation and blockage. After extraction, the extract containing jujube tincture flows out through the filter screen and extract outlet, while the solid material is pushed to the material outlet, where it is squeezed out by a compression device to remove residual extract before being continuously discharged.

[0028] 3) The obtained extract was allowed to settle naturally in a storage tank for 6 hours. The supernatant was then placed in an ethanol vacuum concentration and recovery device and concentrated under vacuum at 55°C and 0.06 MPa to obtain jujube tincture. The volatilized gaseous ethanol was recovered and collected by a condenser.

[0029] 4) The jujube tincture prepared in this embodiment is a reddish-brown clear viscous liquid with a typical sweet jujube aroma, an ethanol content of 17.1%, and a sugar content of 39.1%.

[0030] The above description is merely a specific embodiment of the present invention, used to illustrate the technical principles and core features of the present invention. However, the scope of protection of the present invention is not limited to the embodiments described above. Within the technical concept disclosed in the present invention, any modifications or equivalent substitutions readily conceived by those skilled in the art should be included within the scope of protection of the present invention. The actual scope of protection of the present invention should be determined by the claims.

Claims

1. A process for continuously extracting jujube tincture from jujube peel, characterized in that, Includes the following steps: (1) Select fresh red dates with thick skin, and clean and polish them. (2) Place the jujubes processed in step (1) into a jujube feeding tank, which is equipped with a screw feeder. (3) In the extractant storage tank, prepare an ethanol solution with a concentration of 60% to 90% using food-grade ethanol and water, and heat it to 40 to 60°C. (4) Adjust the extraction tower and inject the ethanol solution obtained in step (3) into the tower until it is full. (5) The red dates in step (2) and the ethanol solution in step (3) are continuously fed into the extraction tower at a volume ratio of 1:2 to 1:

6. (6) In the extraction tower, the jujubes and ethanol solution achieve continuous countercurrent contact and complete mass transfer extraction under the action of the spiral mixing propeller. The propeller speed is controlled at 20-60 rpm and the extraction temperature is 40-60℃. (7) The extract containing jujube tincture obtained in step (6) and the waste jujubes are continuously discharged through the two-phase discharge outlet. (8) Let the extract obtained in step (7) stand in a storage tank for 2 to 6 hours. (9) The supernatant obtained in step (8) is concentrated under reduced pressure at 50–60°C and a vacuum of 0.04–0.06 MPa until the density reaches 1.05 g / cm³. 3 After cooling, jujube tincture is obtained.

2. The continuous extraction process of jujube tincture from jujube peel according to claim 1, characterized in that: The extraction tower in step (4) is an integrated U-shaped cylindrical structure with a heating jacket on the outer wall. The two ends of the U-shaped cylinder are respectively provided with a jujube inlet and outlet, and an extractant inlet and outlet. A spiral mixing propeller is provided inside the cylinder, with its blades having openings and covered with a filter screen, so that the extract can flow in reverse through the filter screen while retaining solid materials. A double spiral device is provided at the bend of the extraction tower to prevent solid blockage. The extract flows out through the micropores, the filter screen and the extract outlet, while the extracted solid materials are transported to the material outlet and discharged after being squeezed by the compression device.

3. The continuous extraction process of jujube tincture from jujube peel according to claim 1, characterized in that: In step (6), the feed flow rate and the speed of the spiral mixer are dynamically adjusted according to the actual extraction effect to achieve continuous countercurrent flow of jujubes and ethanol solution, and the ratio and temperature are optimized in a coordinated manner to obtain the best extraction conditions.

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