Extraction method for tea essence

Abstract

The invention discloses an extraction method for tea essence, which adopts a method of combining ultrasonic wave and supercritical fluid extraction, not only significantly improves the extraction efficiency of the tea essence, but also can effectively retain the natural flavor and healthy components of tea, and through ultrasonic treatment, tea cell walls are destroyed, and the release of effective components is accelerated; the supercritical fluid extraction is used for efficiently extracting target components under a low-temperature condition, heat loss and oxidation reaction are reduced, and the method has relatively high extraction efficiency and relatively low energy consumption, is suitable for industrial large-scale production, and is beneficial for improving product quality and economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of tea extraction, in particular to a method for extracting tea essence. Background Art

[0002] As a common beverage, tea is rich in various nutrients, such as tea polyphenols, caffeine, amino acids, aromatic substances, etc. These ingredients not only directly affect the taste and health value of tea, but also determine its wide application in the food and health care products industry. At present, the extraction methods of tea essence mostly use traditional hot water extraction or immersion methods, but these methods have disadvantages such as long time, low efficiency, and large loss of ingredients. In recent years, ultrasonic extraction and supercritical fluid extraction have gradually been applied, showing advantages in improving extraction efficiency and retaining the natural components of tea. However, single ultrasonic or supercritical fluid technology still has some shortcomings in practical applications, such as long processing time, complex equipment, and difficult operation standardization. Therefore, there is an urgent need for a comprehensive extraction method that can combine the advantages of the two technologies to improve the extraction effect of tea essence, reduce energy consumption and improve economic efficiency. Summary of the Invention

[0003] In response to the above situation, in order to make up for the above-mentioned existing defects, the present invention provides a tea essence extraction method that combines ultrasonic extraction and supercritical fluid extraction technology. This method can improve the extraction efficiency while retaining the natural components of tea polyphenols, caffeine, amino acids and aromatic substances in tea to the greatest extent, thereby ensuring the effect of tea extraction.

[0004] The present invention provides the following technical solution: A method for extracting tea essence proposed by the present invention comprises:

[0005] Step 1: Tea pretreatment

[0006] Select fresh tea leaves, wash them, remove impurities, and cut or crush them into appropriate particle size (1-3mm) as needed.

[0007] Step 2: Ultrasonic treatment

[0008] The treated tea leaves are mixed with a solvent, added to an extraction container, and pretreated using ultrasonic equipment for 5 to 30 minutes. Ultrasonic vibrations destroy the cell walls of the tea leaves, promoting the release of active ingredients. The parameters selected for the ultrasonic equipment are: frequency 20kHz to 100kHz, power 50W to 500W.

[0009] Step 3: Supercritical Fluid Extraction

[0010] The ultrasonically treated tea leaves and solvent are placed in a supercritical fluid extraction device for 10 to 60 minutes. The target components of tea polyphenols, caffeine and amino acids in the tea leaves are accurately extracted by adjusting the temperature and pressure of the supercritical fluid extraction device. The temperature of the supercritical fluid extraction device is set at 40°C to 80°C and the pressure is set at 10MPa to 30Mpa.

[0011] Step 4: Extraction separation

[0012] After supercritical fluid extraction, separation equipment is used to separate the tea essence from the extract. This separation is achieved by reducing the solubility of the supercritical fluid.

[0013] Step 5: Essence collection and post-processing

[0014] The separated tea essence is concentrated, dried or freeze-dried as needed to obtain a tea essence product.

[0015] The invention provides a method for extracting tea essence, which has the following advantages:

[0016] This method combines ultrasonic and supercritical fluid extraction, significantly improving the extraction efficiency of tea essence while effectively preserving the tea's natural flavor and health benefits. Ultrasonic treatment disrupts tea cell walls, accelerating the release of active ingredients. Supercritical fluid extraction efficiently extracts target ingredients at low temperatures, minimizing heat loss and oxidation reactions. This method boasts high extraction efficiency and low energy consumption, making it suitable for large-scale industrial production and potentially improving product quality and economic benefits. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to directions, and the words "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.

[0019] Example 1: Extraction of green tea

[0020] 1. Choose high-quality green tea as raw material;

[0021] 2. Wash the green tea leaves with water to remove surface impurities and dust, cut the tea leaves into 2mm pieces to increase the contact area between the tea leaves and the solvent, thereby improving the extraction efficiency. Use a mixed solvent of ethanol and water (the volume ratio of ethanol to water is 70:30) to improve the solubility of tea polyphenols during the extraction process;

[0022] 3. Mix the processed tea leaves with the solvent, ensuring the tea leaves are fully soaked. Place the tea solution in an ultrasonic cleaner with a frequency of 40kHz and a power of 150W for 20 minutes. The high-frequency vibration of the ultrasound creates tiny bubbles that burst in the solution, generating a strong shock wave that enhances cell rupture in the tea leaves and promotes the release of the active ingredients of tea polyphenols and amino acids.

[0023] 4. Transfer the ultrasonically treated tea solution to a supercritical fluid extraction device, select supercritical carbon dioxide (scCO2) as the solvent, set the temperature of the device to 45°C and the pressure to 30 MPa, so that the carbon dioxide can effectively dissolve the fat-soluble components such as tea polyphenols and aroma in the tea leaves, while maintaining the activity of tea polyphenols and other components. The extraction process lasts about 30 minutes, at which time the supercritical carbon dioxide has the strongest solubility and can quickly extract the main active ingredients in the tea leaves.

[0024] 5. After completing supercritical fluid extraction, the pressure of supercritical carbon dioxide is gradually reduced to convert it back into gas, weakening its solubility. The tea essence is then separated. Through distillation and condensation technology, the supercritical carbon dioxide and dissolved substances in the separated liquid are separated to obtain the tea essence. The tea essence liquid is filtered to remove any solid impurities that may remain in it to ensure the purity of the final extract.

[0025] 6. The filtered tea essence solution is vacuum concentrated to remove excess solvent to obtain a more concentrated tea essence solution. The concentrated tea essence is dried using freeze-drying technology to preserve the natural aroma and active ingredients of the tea and reduce the damage to the ingredients caused by temperature.

[0026] Example 2: Extraction of black tea

[0027] 1. Select high-quality black tea as raw material, wash the black tea leaves to remove impurities, cut the tea leaves into 3mm pieces as required, mix the processed tea leaves with a solvent (a mixture of ethanol and water in a ratio of 60:40) to prepare a tea solution;

[0028] 2. Place the mixed tea solution in an ultrasonic processor, select an ultrasonic device with a frequency of 80kHz and a power of 400W, and perform ultrasonic treatment on the tea solution for 15 minutes to release the effective ingredients of tea polyphenols, caffeine, and amino acids in the black tea.

[0029] 3. Transfer the ultrasonically treated tea solution to a supercritical fluid extraction device, using supercritical carbon dioxide as the solvent. Set the temperature to 60°C, the pressure to 25 MPa, and the extraction time to 40 minutes. Under the dissolution of supercritical carbon dioxide, tea polyphenols and aromatic substances in the tea leaves are effectively extracted while avoiding damage to the ingredients caused by high temperatures.

[0030] 4. After completing the supercritical fluid extraction, gradually reduce the temperature and pressure in the system to weaken the solubility of supercritical carbon dioxide, thereby separating the tea essence. The obtained extract is filtered to remove solid impurities to obtain a solution containing tea essence.

[0031] 5. Place the separated tea essence solution into a vacuum concentration device for concentration to remove excess solvent, and use freeze drying equipment to dry the concentrated tea essence to retain more natural aromatic substances and nutrients.

[0032] Comparative summary of Example 1 (green tea extraction) and Example 2 (black tea extraction):

[0033]

[0034]

[0035] Among them, Example 1 and Example 2 both use ultrasonic and supercritical carbon dioxide extraction technology to efficiently extract the effective ingredients in tea, ensuring the high purity and high quality of the tea essence. For black tea and green tea, the parameters are fine-tuned to adapt to the different characteristics of tea, reflecting the flexibility and universality of this process, taking into account both extraction efficiency and retention of ingredient activity.

[0036] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, material, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, material, or apparatus.

[0037] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for extracting tea essence, characterized in that: The method comprises the following steps: Step 1: Wash the tea leaves and cut or crush them into appropriate particle size (1-3mm) as needed. Step 2: Mix the treated tea leaves with the solvent, add them to the extraction container, and use ultrasonic equipment for pretreatment. Step 3: Place the ultrasonically treated tea leaves and solvent into a supercritical fluid extraction device for supercritical fluid extraction. Step 4: Use separation equipment to separate the tea essence from the extract. Step 5: The separated tea essence is concentrated, dried or freeze-dried as needed to obtain a tea essence product.

2. The method for extracting tea essence according to claim 1, wherein: The supercritical fluid is supercritical carbon dioxide, and the temperature of supercritical fluid extraction is 40° C. to 80° C., and the pressure is 10 MPa to 30 MPa.

3. The method for extracting tea essence according to claim 1, wherein: The raw tea leaves are green tea or black tea.

4. The method for extracting tea essence according to claim 1, wherein: The ultrasonic frequency is 20kHz to 100kHz, the power is 50W to 500W, and the pretreatment time is 5 to 30 minutes.

5. The method for extracting tea essence according to claim 1, characterized in that: The extraction solvent is selected from ethanol, water and a mixture thereof.

6. The method for extracting tea essence according to claim 1, characterized in that: The separated tea essence can be concentrated by vacuum concentration equipment or dried by freeze drying equipment.

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