Preparation method of microcapsule matcha powder and product

Abstract

The application relates to the technical field of microcapsules, in particular to a preparation method of microcapsule matcha powder, which comprises the following steps S1: grinding matcha, then adding heated water for soaking, filtering, and obtaining water-passed matcha powder and a water-extracted solution; S2: adding the water-passed matcha powder into ethanol for soaking, filtering, and obtaining an alcohol-extracted solution and an extraction residue; S3: mixing the water-extracted solution and the extraction residue in a weak alkaline solution, then adding a hydrophilic emulsifier, and high-speed stirring to obtain a wall material emulsion; S4: adding the alcohol-extracted solution into a lipophilic emulsifier, heating and stirring, and removing excessive ethanol until a core material emulsion in the form of milk is obtained; S5: mixing the wall material emulsion and the core material emulsion, high-speed stirring until a uniform emulsion is obtained; and S6: performing spray freeze drying on the uniform emulsion, then sieving, so that the microcapsule matcha powder is obtained. The matcha powder microcapsule prepared by the method can effectively prolong the shelf life of matcha and can retain the complete flavor of matcha.

Description

Technical Field

[0001] This invention relates to the field of microcapsule technology, specifically a method for preparing microcapsule matcha powder and the product thereof. Background Technology

[0002] Matcha powder refers to the ultrafine powder obtained by grinding tencha (steamed green tea). It is rich in tea polyphenols (including phenolic compounds such as catechins) and chlorophyll. Among them, theanine helps improve sleep and relieve anxiety, catechins can reduce the risk of cardiovascular disease and cancer, and chlorophyll has the beneficial effect of enhancing the human body's immunity, which also gives matcha its unique bright green and delicate color.

[0003] The color of matcha is a key indicator for evaluating its quality. For example, GB / T 34778-2017 specifies that Grade 2 matcha should have a "bright emerald green" color, while Grade 1 matcha should have a "bright, vibrant green" color. Simply put, the higher the chlorophyll content in matcha, the brighter the color and the higher the quality. Therefore, those skilled in the art have dedicated themselves to increasing the chlorophyll content in matcha. Traditional tencha manufacturing processes include shade cultivation, steaming, rolling, drying, and grinding. Shade cultivation aims to increase the chlorophyll and amino acid content of the tea leaves, while steaming rapidly deactivates enzymes in fresh tea leaves using high-temperature steam, allowing chlorophyll and other components in the matcha powder to be preserved. However, because chlorophyll is oxidized and decomposed in the air, and light accelerates this decomposition, even high-quality matcha powder can fade and yellow over a long shelf life, leading to a decline in its appearance. For example, the study "Tang Jiazhen. Study on the quality change law and shelf life prediction of matcha during storage [D]. Zhejiang University, 2020" studied the changes of various components such as polyphenols, amino acids, caffeine, and chlorophyll during the storage of matcha.

[0004] Therefore, in order to solve this problem, existing technologies have adopted methods such as light-proof storage, sealing, and controlling storage temperature and humidity to delay the decomposition of chlorophyll in matcha powder and extend its shelf life. However, these methods have limitations, and there is still a lack of a product-oriented method that can effectively extend the shelf life of matcha powder.

[0005] Microencapsulation technology refers to the technique of encapsulating trace amounts of substances in polymer films. It is a micro-packaging technology for storing solids, liquids, and gases, and has been widely used in the food industry for slow release, protection of sensitive components, and improvement of food stability. For example, as early as the 1990s, Wang Huibin et al. proposed the idea of ​​preparing microcapsule tea powder. However, even after more than 20 years, there is still a lack of best-selling related products on the market. Existing microcapsule tea products mainly target single extracts or a certain type of extract from tea, such as tea polyphenol microcapsules, theanine microcapsules, and tea essential oil microcapsules. After brewing, they cannot obtain the complete flavor of tea. This is because the various components in tea have very different properties, making it very difficult to prepare them as a mixture using core materials. For example, tea polyphenols and theanine are soluble in both water and organic solvents, caffeine is only soluble in hot water and slightly soluble in cold water and ethanol, and chlorophyll is insoluble in water but soluble in organic solvents. Therefore, current microcapsule tea products cannot simultaneously cover the multiple complex components in tea and cannot restore the original flavor of tea.

[0006] In summary, this invention aims to provide a microcapsule product that preserves the original flavor of matcha as much as possible and can extend the shelf life of matcha. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a microcapsule matcha powder that can at least maintain the flavor of matcha and extend its shelf life, as well as a method for preparing the same.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A method for preparing microcapsule matcha powder includes the following steps:

[0010] S1: Grind the tea leaves into powder, then add hot water to soak, filter, and obtain tea powder and water extract solution;

[0011] S2: Add the rinsed tea powder to ethanol for soaking, filter, and obtain the ethanol extract solution and the extraction residue;

[0012] S3: Add the aqueous extract solution and the extraction residue to a weakly alkaline solution, then add a hydrophilic emulsifier and stir at high speed to obtain a wall material emulsion (aqueous phase).

[0013] S4: Add the alcohol extract solution to the lipophilic emulsifier, heat and stir to remove excess ethanol until a milky core material emulsion (oil phase) is obtained.

[0014] S5: Mix the wall material emulsion and the core material emulsion, stir at high speed, and slowly add water dropwise while stirring until a uniform emulsion is obtained;

[0015] S6: Spray freeze-dry the uniform emulsion and then sieve it to obtain the microcapsule matcha powder.

[0016] Furthermore, in step S1, the temperature of the hot water is 40~50℃.

[0017] Preferably, in step S1, the soaking time is 24-72 hours.

[0018] Preferably, in step S2, the soaking time is 48-72 hours.

[0019] Furthermore, in step S3, the hydrophilic emulsifier is preferably a colorless, non-toxic, and odorless edible hydrophilic emulsifier, including at least one of sucrose fatty acid monoester and xanthan gum.

[0020] Furthermore, in step S3, the weight ratio of the aqueous extract solution to the hydrophilic emulsifier is 1:0.08-0.12.

[0021] Furthermore, in step S3,

[0022] It is worth noting that the extraction residue mainly includes insoluble components such as plant proteins and cellulose. More than 80% of tea protein is alkali-soluble, and the commonly used extraction method is alkaline extraction. However, this method has a very low extraction rate under weakly alkaline conditions, and strong alkalinity may cause protein denaturation and the formation of lysine. Therefore, the method of this invention avoids the extraction of tea protein directly. The tea protein participates in emulsification directly in the form of the extraction residue, and its reaction with the emulsifier sucrose fatty acid monoester increases hydrophilicity, preventing protein precipitation.

[0023] Furthermore, in step S4, the lipophilic emulsifier is preferably a colorless, non-toxic, and odorless edible lipophilic emulsifier, including at least one of polyglycerol fatty acid esters, Tween-80, and Tween-60.

[0024] Furthermore, in step S4, the weight ratio of the alcohol extract to the lipophilic emulsifier is 1:0.1-0.2.

[0025] Furthermore, in step S5, the speed of the high-speed stirring is 8000-14000 r / min.

[0026] It is worth noting that matcha is a special tea product, unlike traditional tea leaves. It requires a grinding process to achieve a micron-sized powder, making it particularly suitable for microcapsule production. This invention employs a water-extraction followed by alcohol extraction method, extracting (heat-soluble) water-soluble substances (tea polyphenols, theanine, etc.) from matcha as wall materials and alcohol-soluble substances (chlorophyll, lipids, etc.) as core materials. Then, a simultaneous emulsification method is used to mix the water-soluble and alcohol-soluble extracts separately, creating an O / W emulsion through ultra-high-speed stirring. Finally, spray drying is used to form microcapsules, preserving the original composition and proportions of the matcha and maintaining its original flavor. The hydrophilic and lipophilic emulsifiers used in this invention are both edible and non-toxic, and added in small amounts, thus not affecting the product's flavor. The only extractants used in this invention are ethanol and water; the ethanol can be removed in subsequent processes by heating and stirring, ensuring it does not remain in the product.

[0027] It is worth noting that the appearance of the matcha microcapsules of the present invention is similar to that of general matcha products, both being in the form of fine powder, but the color is white. After being gently rubbed by hand, it turns green. After brewing, it presents a bright green color. The brewing time is significantly shorter than that of general matcha products, making it suitable for instant matcha products.

[0028] The beneficial effects of this invention are:

[0029] 1. The matcha powder microcapsules of the present invention can effectively extend the shelf life of matcha, and will not deteriorate or fade due to oxidation. The matcha powder microcapsules stored for a long time can still maintain a bright green color after brewing.

[0030] 2. The matcha powder microcapsules of the present invention have low preparation cost, use the components of matcha itself as the wall material and core material of the microcapsules, use a small amount of external reagents, and will not affect the flavor of matcha. Attached Figure Description

[0031] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be described in further detail below, but the scope of protection of the present invention is not limited to the following description.

[0033] Example 1

[0034] This embodiment prepares a matcha microcapsule tea powder using the following specific method:

[0035] Tencha (purchased from Mabian Gaoshan Tea Industry Co., Ltd.) was dried, ground, and passed through an 800-mesh sieve to obtain matcha powder. The matcha powder was added to a thermostatic magnetic stirrer with water, and the temperature was controlled at 50℃. The amount of water added was 15 times the weight of the matcha, and the stirring time was 24 hours. After stirring, the mixture was allowed to stand for a period of time, and then filtered to obtain a water extract and a filter residue. The filter residue was soaked in 95% ethanol and stirred on a magnetic stirrer. The amount of ethanol added was 5 times the weight of the matcha, and the stirring time was 48 hours. After stirring, the mixture was allowed to stand and filtered to obtain an alcohol extract and the final filter residue.

[0036] Add the above aqueous extract and final filter residue to a NaOH solution (pH=9), then add the emulsifiers sucrose fatty acid monoester and xanthan gum. The amount of emulsifier added is quantitatively based on the weight of the aqueous extract. The weight ratio of the aqueous extract, sucrose fatty acid monoester, and xanthan gum is 10:0.8:0.2. Stir in a magnetic stirrer at 1000 r / min until an emulsion (aqueous phase) is formed. Add the above alcohol extract to polyglycerol fatty acid ester (10:1) and heat and stir in a thermostatic magnetic stirrer at 200 r / min and 30℃ until excess solvent evaporates, forming an emulsion (oil phase). Mix the hydrophilic emulsion and the lipophilic emulsion, and add them to a high-speed shear emulsifier (model: LYE500W-T) for high-speed shearing at 10000 rpm for 2 min to obtain a homogeneous emulsion. The emulsion was added to an experimental freeze spray dryer (Y-3000 model, machine parameters: vacuum pressure 50Pa, air volume 5m³ / h). 3 Spray drying is performed at a spray speed of 1000 m / min and a spray temperature not exceeding 30°C, and then the mixture is passed through an 800-mesh sieve to obtain microcapsule matcha powder.

[0037] Example 2

[0038] This embodiment prepares a matcha microcapsule tea powder using the following specific method:

[0039] After drying, the matcha powder is ground and passed through an 800-mesh sieve. The matcha powder is then added to a thermostatic magnetic stirrer with water, maintaining a temperature of 60°C. The amount of water added is 15 times the weight of the matcha powder, and the stirring time is 48 hours. After stirring, the mixture is allowed to stand for a period of time, then filtered to obtain a water extract and a filter residue. The filter residue is then soaked in 95% ethanol and stirred on a magnetic stirrer. The amount of ethanol added is 5 times the weight of the matcha powder, and the stirring time is 48 hours. After stirring, the mixture is allowed to stand and then filtered to obtain an alcohol extract and the final filter residue.

[0040] The above aqueous extract and final filter residue were added to a NaOH solution (pH=9), followed by the emulsifiers sucrose fatty acid monoester and xanthan gum. The amount of emulsifier added was quantified by weight of the aqueous extract, with a weight ratio of 10:0.8:0.2. The mixture was stirred in a magnetic stirrer at 1000 rpm until an emulsion (aqueous phase) was formed. The above alcoholic extract was then added to Tween 80 (8:1) and heated and stirred in a thermostatic magnetic stirrer at 200 rpm and 30°C until excess solvent evaporated, forming an emulsion (oil phase). The hydrophilic and lipophilic emulsions were mixed and added to a high-speed shear emulsifier (model: LYE500W-T) for high-speed shearing at 10000 rpm for 5 min to obtain a homogeneous emulsion. The emulsion was added to an experimental freeze spray dryer for spray drying, and then passed through an 800-mesh sieve to obtain microcapsule matcha powder.

[0041] Example 3

[0042] This embodiment prepares a matcha microcapsule tea powder using the following specific method:

[0043] After drying, the matcha powder is ground and passed through an 800-mesh sieve. The matcha powder is then added to a thermostatic magnetic stirrer with water, maintaining a temperature of 50°C. The amount of water added is 15 times the weight of the matcha powder, and the stirring time is 24 hours. After stirring, the mixture is allowed to stand for a period of time, then filtered to obtain a water extract and a filter residue. The filter residue is then soaked in 95% ethanol and stirred on a magnetic stirrer. The amount of ethanol added is 5 times the weight of the matcha powder, and the stirring time is 48 hours. After stirring, the mixture is allowed to stand and then filtered to obtain an alcohol extract and the final filter residue.

[0044] The above aqueous extract and final filter residue were added to a NaOH solution (pH=9), followed by the emulsifiers sucrose fatty acid monoester and xanthan gum. The amount of emulsifier added was quantified by weight of the aqueous extract, with a weight ratio of 12:0.8:0.2. The mixture was stirred in a magnetic stirrer at 1000 rpm until an emulsion (aqueous phase) was formed. The above alcoholic extract was then added to Tween 80 (8:1) and heated and stirred in a thermostatic magnetic stirrer at 200 rpm and 30°C until excess solvent evaporated, forming an emulsion (oil phase). The hydrophilic and lipophilic emulsions were mixed and added to a high-speed shear emulsifier (model: LYE500W-T) for high-speed shearing at 11000 rpm for 5 min to obtain a homogeneous emulsion. The emulsion was added to an experimental freeze spray dryer for spray drying, and then passed through an 800-mesh sieve to obtain microcapsule matcha powder.

[0045] Experimental Example 1

[0046] The changes in chlorophyll content in microencapsulated matcha powder under environmental influences were detected. Microencapsulated matcha powders from Examples 1-3 were stored under room temperature, high temperature, and strong light conditions as control examples. Specific methods are as follows:

[0047] 200g of the microcapsule matcha powder from Examples 1-3 were used for storage simulation in a dry, cool, dark indoor environment (25℃), a constant temperature incubator (60℃), and a greenhouse environment with a light intensity of 10000lx. An equal amount of commercially available matcha powder (200g) was used as a control group. The storage period was 30 days. During storage, the microcapsules were laid flat to increase the surface area in contact with oxygen. Chlorophyll content was measured every 10 days.

[0048] The detection method refers to industry standard NY / T 3082-2017. The procedure involves sampling, adding a small amount of water to dissolve the microcapsules, then adding a 1:1 ethanol / acetone solution to extract the chlorophyll solution. The absorbance at 645 nm and 663 nm is measured spectrophotometrically, and the chlorophyll content is calculated using the Arnon formula.

[0049] The test results are as follows:

[0050] Table 1. Changes in chlorophyll content of microencapsulated matcha powder at room temperature.

[0051]

[0052] Table 2. Changes in chlorophyll content of microencapsulated matcha powder under high temperature conditions.

[0053]

[0054] Table 3. Changes in chlorophyll content of microencapsulated matcha powder under light conditions.

[0055]

[0056] Experimental Example 2

[0057] Sensory evaluation of the microcapsule matcha powder of the present invention was conducted, with ordinary matcha powder as a comparison. The method is as follows:

[0058] Take the matcha powder from Example 1 of this invention and commercially available matcha powder (brand: Guizhou Guicha) and brew them with hot water. Perform sensory tests on appearance and flavor. Then take an equal amount of the above matcha powder and place it in an outdoor environment without avoiding light for 20 days. Then perform sensory tests using the same method.

[0059] Sensory testing methods:

[0060] Add 3.0g of tea powder to 150mL of boiling water in a tea tasting cup, cover and steep for 10 minutes. Evaluate the color and flavor of the tea liquor. The evaluation is conducted by 5 qualified senior tea tasters, and the result with the highest degree of overlap is recorded. The tea liquor quality is then scored on a 100-point scale (scoring standards follow GB / T 23776-2018), and the average value is taken.

[0061] 1) Liquor color: The color type and intensity of the matcha are evaluated;

[0062] 2) Flavor: Evaluate the strength, thickness, mellowness, astringency, purity, and freshness of the matcha.

[0063] The review results are as follows:

[0064] Table 4 Sensory test results

[0065]

[0066] It is evident that the matcha powder prepared by the method of this invention has almost no difference in flavor and taste compared to commercially available matcha powder, but has a better color retention effect and a significantly improved shelf life.

[0067] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for preparing microcapsule matcha powder, characterized in that, Includes the following steps: S1: Grind the tea leaves into powder, then add hot water to soak, filter, and obtain tea powder and water extract solution; S2: Add the rinsed tea powder to ethanol for soaking, filter, and obtain the ethanol extract solution and the extraction residue; S3: The aqueous extraction solution and the extraction residue are added to a weakly alkaline solution and mixed, then a hydrophilic emulsifier is added and stirred at high speed to obtain a wall material emulsion; S4: Add the alcohol extraction solution to the lipophilic emulsifier, heat and stir to remove excess ethanol until a milky core material emulsion is obtained. S5: Mix the wall material emulsion and the core material emulsion, and stir at high speed until a uniform emulsion is obtained; S6: Spray freeze-dry the uniform emulsion and then sieve it to obtain the microcapsule matcha powder.

2. The preparation method according to claim 1, characterized in that: In step S1, the temperature of the hot water is 40~50℃.

3. The preparation method according to claim 1, characterized in that: In step S3, the hydrophilic emulsifier includes at least one of sucrose fatty acid monoester and xanthan gum.

4. The preparation method according to claim 1, characterized in that: In step S3, the weight ratio of the aqueous extract solution to the hydrophilic emulsifier is 1:0.08-0.

12.

5. The preparation method according to claim 1, characterized in that: In step S3, the pH of the weakly alkaline solution is 8-9.

6. The preparation method according to claim 1, characterized in that: In step S4, the lipophilic emulsifier includes at least one of polyglycerol fatty acid ester, Tween-80, and Tween-60.

7. The preparation method according to claim 1, characterized in that: In step S4, the weight ratio of the alcohol extract to the lipophilic emulsifier is 1:0.1-0.

2.

8. The preparation method according to claim 1, characterized in that: In step S5, the speed of the high-speed stirring is 8000-14000 r / min.

9. Microcapsule matcha powder prepared by any one of the preparation methods described in claims 1-8.

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