Floral compound matcha powder and preparation method thereof

Abstract

This invention discloses a floral-scented composite matcha powder and its preparation method, belonging to the field of food processing technology, including the following steps: (1) preparing a natural deep eutectic solvent, wherein the natural deep eutectic solvent contains hydrogen bond acceptors and hydrogen bond donors; (2) mixing matcha powder, floral fragrance source and natural deep eutectic solvent, stirring and extracting at 30-70℃, so that the aroma components in the floral fragrance source dissolve in the natural deep eutectic solvent and are adsorbed by the matcha powder; (3) solid-liquid separation, collecting the solid part; (4) drying, to obtain floral-scented composite matcha powder. This invention simultaneously completes the extraction of floral fragrance components and the adsorption and compounding of matcha powder, simplifying the process flow. The low-temperature operation throughout protects the heat-sensitive aroma components and matcha color, requires no organic solvent, has high product safety, and the natural deep eutectic solvent can be recycled and reused. This invention can select different floral fragrance sources such as gardenia, cherry blossom, and bamboo leaves to prepare floral-scented composite matcha powders with various flavors.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a floral-scented compound matcha powder and its preparation method. Background Technology

[0002] Floral-scented tea products have gained widespread attention from consumers in recent years. Traditional floral-scented teas are usually prepared by simply mixing tea leaves with flowers, scenting them, or adding them after extraction.

[0003] According to the search, patent CN103271190B discloses a matcha-flavored chrysanthemum tea powder and its preparation method. It uses wild chrysanthemum, chrysanthemum leaves and other raw materials, and produces granular powder through processes such as steam treatment, extraction, fermentation, boiling and spray drying. The product has a chrysanthemum fragrance. Although this technology achieves the combination of matcha and chrysanthemum, it has the following shortcomings: (1) The preparation process is complicated, involving multiple processes such as steaming, fermentation and boiling, and the processing temperature is high (up to 100℃), which can easily lead to the loss of heat-sensitive aroma components; (2) The matcha powder is added in the later stage in the form of "steamed seasoning powder". After steaming, the fresh color and flavor of the matcha itself are destroyed; (3) The product is a granular powder, which is different from the application scenario of powdered matcha powder; (4) The source of floral fragrance is limited to chrysanthemum and does not involve other floral fragrance types such as gardenia and cherry blossom.

[0004] Natural deep eutectic solvents (NADES) are a class of green solvents developed in recent years. They are formed by hydrogen bond acceptors (such as betaine and choline chloride) and hydrogen bond donors (such as citric acid, glycerol, and xylitol) through hydrogen bonding. NADES has advantages such as biodegradability, non-toxicity, simple preparation, and good solubility for various bioactive components, and has been widely used in the food and pharmaceutical industries. In the food industry, NADES has been used to extract active ingredients such as tea polyphenols, flavonoids, and anthocyanins. For example, some studies have used betaine-lactic acid NADES to extract tea polyphenols, with significantly higher extraction efficiency than traditional solvents; other patents disclose technical solutions for using NADES to extract active components from tea for the preparation of anti-glycation products. However, existing NADES extraction technologies all use the extract (liquid phase) as the target product. After extraction, the target component needs to be separated from NADES, or the extract containing NADES can be used directly as an intermediate product. There is no technical solution that combines NADES extraction technology with adsorption and compounding of solid matrix materials simultaneously, with the solid part as the final product.

[0005] Furthermore, in existing methods for preparing floral-scented tea products, the extraction and compounding of floral components into tea powder are usually separate processes—the floral components are first extracted with water or organic solvents, concentrated, and then mixed with tea powder. This step-by-step process has the following problems: (1) Heating during extraction and concentration can easily lead to the loss of heat-sensitive floral components; (2) The use of organic solvents poses a risk of solvent residue; (3) It is difficult to ensure the uniformity of the mixture between the extract and the tea powder; (4) The process route is long and energy consumption is high.

[0006] Therefore, developing a preparation method that can simultaneously extract floral fragrance components and compound them with matcha powder under low-temperature conditions, without the need for organic solvents, and while preserving the natural color and flavor of matcha, is of significant practical importance. Summary of the Invention

[0007] The purpose of this invention is to overcome the aforementioned technical difficulties and provide a floral-scented compound matcha powder and its preparation method.

[0008] To achieve the above objectives, the technical solution adopted is: a floral-scented compound matcha powder and its preparation method, comprising the following steps: (1) Prepare a natural deep eutectic solvent, wherein the natural deep eutectic solvent contains a hydrogen bond acceptor and a hydrogen bond donor; (2) Mix matcha powder, floral fragrance source and natural deep eutectic solvent obtained in step (1), wherein the mass ratio of matcha powder to floral fragrance source is 1:0.1 to 1:1 and the mass ratio of natural deep eutectic solvent to matcha powder is 2:1 to 10:1. Stir and extract at 30–70°C to dissolve the aroma components in the floral fragrance source in the natural deep eutectic solvent and adsorb them by the matcha powder. (3) Separate the solid and liquid components of the mixture obtained in step (2) and collect the solid portion; (4) Dry the solid part obtained in step (3) to obtain floral-scented compound matcha powder.

[0009] Furthermore, the natural deep eutectic solvent in step (1) also contains water, and the molar ratio of water to hydrogen bond acceptor is 0.5:1 to 2:1.

[0010] Furthermore, in step (1), the hydrogen bond acceptor is selected from one or more of betaine, choline chloride, and L-carnitine; and the hydrogen bond donor is selected from one or more of citric acid, malic acid, lactic acid, glycerol, and xylitol.

[0011] Furthermore, in step (1), the hydrogen bond acceptor is betaine, and the hydrogen bond donor is a mixture of citric acid and glycerol, with the molar ratio of betaine, citric acid and glycerol being 1:1:2 to 1:2:4.

[0012] Furthermore, in step (2), the mass ratio of matcha powder to floral fragrance source is 1:0.3 to 1:0.6.

[0013] Furthermore, in step (2), the mass ratio of the natural deep eutectic solvent to the matcha powder is 4:1 to 6:1.

[0014] Furthermore, the floral fragrance source in step (2) is selected from one or more of gardenia, cherry blossom, and bamboo leaves.

[0015] Furthermore, in step (2), ultrasonic assistance is applied during the stirring extraction process, with an ultrasonic power of 100–500 W and a frequency of 20–40 kHz; in step (3), the solid-liquid separation is centrifugal separation or pressure filtration separation, with a centrifugal speed of 6000–12000 rpm and a centrifugation time of 5–20 minutes.

[0016] Furthermore, the drying in step (4) is vacuum drying or freeze drying, the drying temperature is 35–50℃, and the moisture content is ≤6%.

[0017] Furthermore, after drying in step (4), the dried product is also sieved and packaged with nitrogen.

[0018] The beneficial effects of adopting the above scheme are as follows: After the application of this floral-scented compound matcha powder and its preparation method: First, the floral fragrance components are extracted with water or organic solvents, concentrated, and then mixed with tea powder. This invention simultaneously completes the extraction of floral fragrance components and the adsorption and compounding of matcha powder. During the extraction process, the floral fragrance components are immediately adsorbed by the matcha powder as soon as they dissolve, eliminating the need for separate concentration and mixing steps, significantly simplifying the process and reducing energy consumption.

[0019] Extraction is performed using a natural deep eutectic solvent at 30-70℃, with low-temperature operation throughout, which effectively protects the heat-sensitive aroma components in the floral sources such as gardenia and cherry blossom, as well as the fresh and vibrant color of the matcha itself.

[0020] The natural deep eutectic solvent consists of hydrogen bond acceptors (such as betaine and choline chloride) and hydrogen bond donors (such as citric acid, glycerol, and xylitol), all of which are food-grade raw materials. The LD50 (oral, rat) of betaine and choline chloride is 3.15-5.00 g / kg, indicating high safety. This invention does not use organic solvents during the extraction process, resulting in a final product free of solvent residue.

[0021] In this invention, trace amounts of NADES remain in the dried compound matcha powder, unexpectedly acting as a natural preservative and helping to extend the product's shelf life.

[0022] This invention uses a solid component (matcha powder + adsorbed floral fragrance components) as the final product. The technical approach is the opposite of the existing technology. The NADES liquid after solid-liquid separation can be recycled and reused, which is in line with the concept of green chemistry.

[0023] This invention can prepare a variety of flavored floral-scented compound matcha powders by selecting different floral fragrance sources (gardenia, cherry blossom, bamboo leaves, etc.). The product is in powder form, retaining the traditional application form of matcha, and can be used directly for brewing or as a food ingredient. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Example

[0025] A floral-scented compound matcha powder and its preparation method include the following steps: (1) Preparation of NADES Weigh out 117.1 g (1.0 mol) of betaine, 192.1 g (1.0 mol) of citric acid, and 184.2 g (2.0 mol) of glycerol, mix them, and then add 36.0 g (2.0 mol, calculated as betaine) of deionized water. Place the mixture in an 80°C water bath and heat with stirring for 30 minutes until a homogeneous, transparent liquid is formed. Cool to room temperature for later use. The viscosity of the obtained NADES is 150 mPa·s (25°C).

[0026] (2) Gardenia pretreatment Take 1000g of fresh gardenia flowers, remove the calyx and pedicels, wash with deionized water, and drain. Spread the washed gardenia flowers evenly on a tray and freeze at -18℃ for 18 hours. After freezing, thaw the gardenia flowers naturally for 30 minutes before use.

[0027] (3) In-situ extraction-compound Weigh 200g of matcha powder (particle size D90=18μm, specific surface area 1.4m² / g), add 80g of pretreated gardenia flowers from step (2) (matcha powder to floral fragrance source mass ratio 1:0.4), and then add 1000g of NADES prepared in step (1) (natural deep eutectic solvent to matcha powder mass ratio 5:1). Place the mixture in a constant temperature stirring extraction tank and extract at 50℃ and 200rpm for 90 minutes.

[0028] (4) Solid-liquid separation Transfer the mixture obtained in step (3) to a centrifuge and centrifuge at 8000 rpm for 10 minutes. Collect the solid fraction and recover the liquid fraction (NADES) for later use.

[0029] (5) Drying The solid portion obtained in step (4) was spread evenly in a vacuum drying tray and dried at 45°C and a vacuum degree of 0.09 MPa for 4 hours until the moisture content was 5.2%. The dried composite matcha powder was emerald green and had a gardenia fragrance.

[0030] (6) Sieving and packaging The dried product is passed through an 80-mesh sieve to remove agglomerated particles, and then packaged with nitrogen to obtain floral-scented compound matcha powder.

[0031] Comparative Example 1: (1) Gardenia pretreatment Same as step (2) in Example 1.

[0032] (2) Gardenia flower water extract Take 80g of pretreated gardenia flowers, add 1000mL of deionized water, and extract at 84℃ for 2 hours (extraction temperature 84-88℃). Filter to obtain gardenia flower water extract.

[0033] (3) Concentration of aqueous extract Gardenia flower water extract was concentrated under vacuum at 60℃ to 1 / 5 of its original volume to obtain a concentrated solution.

[0034] (4) Mix with matcha powder Weigh 200g of matcha powder (same batch as in Example 1), add it to the concentrated liquid obtained in step (3), and stir to mix evenly.

[0035] (5) Drying Same as step (5) in Example 1.

[0036] (6) Sieving and packaging Same as step (6) in Example 1.

[0037] Comparative Example 2: (1) Preparation of NADES Same as step (1) in Example 1.

[0038] (2) Gardenia pretreatment Same as step (2) in Example 1.

[0039] (3) NADES extraction (without matcha) Take 80g of gardenia flowers, add 1000g of NADES, and extract by stirring at 50℃ for 90 minutes.

[0040] (4) Solid-liquid separation Centrifuge the extract mixture (8000 rpm, 10 minutes), collect the liquid fraction (NADES extract), and discard the solid residue.

[0041] (5) Mix with matcha powder Weigh 200g of matcha powder (same batch as in Example 1), add the NADES extract obtained in step (4), and stir to mix evenly.

[0042] (6) Drying Same as step (5) in Example 1.

[0043] (7) Sieving and packaging Same as step (6) in Example 1.

[0044] Comparative Example 3: (1) Gardenia pretreatment Same as step (2) in Example 1.

[0045] (2) Gardenia flowers dried and pulverized The pretreated gardenia flowers were dried at 50℃ for 12 hours and then pulverized through a 60-mesh sieve to obtain gardenia flower powder.

[0046] (3) Mix with matcha powder Weigh 200g of matcha powder (same batch as in Example 1), add 80g of gardenia powder (the mass ratio of matcha powder to floral source is 1:0.4), and mix in a low-temperature ball mill at 15°C and 100 rpm for 10 minutes.

[0047] (4) Drying Same as step (5) in Example 1.

[0048] (5) Sieving and packaging Same as step (6) in Example 1.

[0049] Comparative Example 4: (1) Preparation of NADES Weigh 139.6 g (1.0 mol) of choline chloride and 90.1 g (1.0 mol) of lactic acid, mix them, and add 18.0 g (1.0 mol, calculated as choline chloride) of deionized water. Place the mixture in a 70°C water bath and stir and heat for 20 minutes until a homogeneous and transparent liquid is formed. Cool to room temperature for later use.

[0050] (2) Gardenia pretreatment Same as step (2) in Example 1.

[0051] (3) In-situ extraction-compound Weigh 200g of matcha powder (same batch as in Example 1), add 80g of pretreated gardenia flowers (matcha powder to floral fragrance source mass ratio 1:0.4), and then add 1000g of NADES prepared in step (1) (natural deep eutectic solvent to matcha powder mass ratio 5:1). Place the mixture in a constant temperature stirring extraction tank and extract at 50℃ and 200rpm for 90 minutes.

[0052] (4) Solid-liquid separation Same as step (4) in Example 1.

[0053] (5) Drying Same as step (5) in Example 1.

[0054] (6) Sieving and packaging Same as step (6) in Example 1. Example

[0055] The applicant used linalool, a characteristic aroma component of gardenia, as a representative component, and determined the retention rate of the processed samples of Example 1 and Comparative Examples 1-4 (calculated with the total amount of linalool in the gardenia raw material being 100%). The results are shown in Table 1 below: Group Linalool retention rate after processing (%) Linalool retention rate (%) after 60 days of storage Example 1 86.3 72.5 Comparative Example 1 42.6 28.3 Comparative Example 2 81.2 65.8 Comparative Example 3 68.5 41.2 Comparative Example 4 78.6 61.3 Table 1 The applicant stated that, according to the data in the table above, Example 1 showed the best color-protecting effect, with a chlorophyll retention rate of 86.7%, which was 21.5 percentage points higher than the traditional water extraction method (Comparative Example 1). This was because the low-temperature operation (50℃ vs 84℃) avoided the thermal degradation of chlorophyll. It was also 8.4 percentage points higher than the non-integrated process (Comparative Example 2), indicating that the in-situ adsorption of matcha powder during the extraction process reduced the impact of subsequent mixing operations on the color. It was 24.9 percentage points higher than the direct mixing of dry powder (Comparative Example 3), indicating that the betaine and citric acid remaining in NADES had antioxidant effects and inhibited the oxidative degradation of chlorophyll. It was 7.2 percentage points higher than the choline chloride-lactic acid system (Comparative Example 4), indicating that the betaine-citric acid-glycerol system had a better antioxidant color-protecting effect. Example

[0056] The applicant stored the samples from Example 1 and Comparative Examples 1-4 at 45°C for 30 days using accelerated storage, and measured the changes in chlorophyll content. The retention rate was calculated with an initial value of 100%. The results are shown in Table 2 below: Group Initial chlorophyll content (mg / g) Chlorophyll retention rate after 30 days (%) Example 1 4.82 86.7 Comparative Example 1 4.75 65.2 Comparative Example 2 4.78 78.3 Comparative Example 3 4.80 61.8 Comparative Example 4 4.76 79.5 Table 2 The results showed that Example 1 had the best color-protecting effect, with a chlorophyll retention rate of 86.7%, which was 21.5 percentage points higher than the traditional water extraction method (Comparative Example 1). This was because the low-temperature operation (50℃ vs 84℃) avoided the thermal degradation of chlorophyll. It was also 8.4 percentage points higher than the non-integrated process (Comparative Example 2), indicating that the in-situ adsorption of matcha powder during the extraction process reduced the impact of subsequent mixing operations on color. It was 24.9 percentage points higher than the direct mixing of dry powder (Comparative Example 3), indicating that the betaine and citric acid remaining in NADES had antioxidant effects and inhibited the oxidative degradation of chlorophyll. It was 7.2 percentage points higher than the choline chloride-lactic acid system (Comparative Example 4), indicating that the betaine-citric acid-glycerol system had a better antioxidant color-protecting effect. Example

[0057] The applicant determined the DPPH free radical scavenging ability of each sample in Example 1 and Comparative Examples 1-4, expressed as IC50 value (μg / mL) (the smaller the value, the stronger the activity). The results are shown in Table 3 below: Group IC50 (μg / mL) Example 1 95.6 Comparative Example 1 178.3 Comparative Example 2 112.4 Comparative Example 3 156.8 Comparative Example 4 128.7 Pure matcha powder (control) 165.2 Table 3 As can be seen from Table 3, the antioxidant activity of Example 1 is significantly better than that of the comparative examples and pure matcha powder, with an IC50 value of 95.6 μg / mL, which is about 1.86 times that of Comparative Example 1 (traditional water extraction method), 1.18 times that of Comparative Example 2 (non-integrated process), 1.64 times that of Comparative Example 3 (direct mixing of dry powder), and 1.35 times that of Comparative Example 4 (choline chloride-lactic acid system). Example

[0058] The applicant reused the NADES recovered in Example 1 three times. The linalool retention rate was 86.3% in the first reuse, 84.7% in the second reuse (a decrease of 1.6 percentage points from the first reuse), and 83.2% in the third reuse (a decrease of 3.1 percentage points from the first reuse), indicating that NADES has good recyclability. Example

[0059] Based on Example 1, when the molar ratio of betaine, citric acid and glycerol was 1:1:3, the linalool retention rate of the resulting compound matcha powder was increased by about 3.2 percentage points and the chlorophyll retention rate was increased by about 2.1 percentage points compared with Example 1, indicating that the molar ratio of betaine, citric acid and glycerol of 1:1:3 has a better effect on the extraction and protection of gardenia aroma. Example

[0060] Based on Example 1, the applicant adjusted the mass ratio of matcha powder to floral fragrance source to 1:0.6. The resulting composite matcha powder had a moderate floral fragrance intensity and better aroma coordination than Example 1 with a mass ratio of 1:0.4. The linalool retention rate was basically the same as that of Example 1, but the sensory score was improved by about 8%, indicating that 1:0.3 to 1:0.6 is the preferred mass ratio range for the gardenia and matcha composite. Example

[0061] Based on Example 1, the applicant increased the mass ratio of NADES to matcha powder to 6:1. During the extraction process, the solvent volume of NADES increased, and the dissolution of gardenia fragrance components was more complete. The linalool retention rate of the resulting composite matcha powder was increased by about 2.5 percentage points compared with Example 1, but the drying time was slightly prolonged. Considering both extraction efficiency and energy consumption, 4:1 to 6:1 is the preferred mass ratio range.

[0062] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0063] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A floral compound matcha powder and a method for preparing the same, characterized by comprising: Includes the following steps: ​ (1) Prepare a natural deep eutectic solvent, wherein the natural deep eutectic solvent contains a hydrogen bond acceptor and a hydrogen bond donor; (2) Mix matcha powder, floral fragrance source and natural deep eutectic solvent obtained in step (1), wherein the mass ratio of matcha powder to floral fragrance source is 1:0.1 to 1:1 and the mass ratio of natural deep eutectic solvent to matcha powder is 2:1 to 10:

1. Stir and extract at 30–70°C to dissolve the aroma components in the floral fragrance source in the natural deep eutectic solvent and adsorb them by the matcha powder. (3) Separate the solid and liquid components of the mixture obtained in step (2) and collect the solid portion; (4) Dry the solid part obtained in step (3) to obtain floral-scented compound matcha powder.

2. The floral complexed matcha powder according to claim 1, characterized by: The natural deep eutectic solvent in step (1) also contains water, and the molar ratio of water to hydrogen bond acceptor is 0.5:1 to 2:

1.

3. The floral-scented compound matcha powder and its preparation method according to claim 1, characterized in that: In step (1), the hydrogen bond acceptor is selected from one or more of betaine, choline chloride, and L-carnitine; the hydrogen bond donor is selected from one or more of citric acid, malic acid, lactic acid, glycerol, and xylitol.

4. The floral-scented compound matcha powder and its preparation method according to claim 1, characterized in that: The hydrogen bond acceptor in step (1) is betaine, and the hydrogen bond donor is a mixture of citric acid and glycerol, with the molar ratio of betaine, citric acid and glycerol being 1:1:2 to 1:2:

4.

5. The floral-scented compound matcha powder and its preparation method according to claim 1, characterized in that: In step (2), the mass ratio of matcha powder to floral fragrance source is 1:0.3 to 1:0.

6.

6. The floral-scented compound matcha powder and its preparation method according to claim 1, characterized in that: The mass ratio of the natural deep eutectic solvent to matcha powder in step (2) is 4:1 to 6:

1.

7. The floral-scented compound matcha powder and its preparation method according to claim 1, characterized in that: The floral fragrance source in step (2) is selected from one or more of gardenia, cherry blossom, and bamboo leaves.

8. The floral-scented compound matcha powder and its preparation method according to claim 1, characterized in that: In step (2), ultrasonic assistance is applied during the stirring extraction process, with an ultrasonic power of 100–500 W and a frequency of 20–40 kHz; in step (3), the solid-liquid separation is centrifugal separation or pressure filtration separation, with a centrifugal speed of 6000–12000 rpm and a centrifugation time of 5–20 minutes.

9. The floral-scented compound matcha powder and its preparation method according to claim 1, characterized in that: The drying in step (4) is vacuum drying or freeze drying, with a drying temperature of 35–50°C, until the moisture content is ≤6%.

10. The floral-scented compound matcha powder and its preparation method according to claim 1, characterized in that: After drying in step (4), the dried product is further subjected to sieving and nitrogen-filled packaging.