Method for preparing spice by taking black tea as raw material

Abstract

The invention provides a method for preparing spice by taking black tea as a raw material, which comprises the following steps: 1) preparing a black tea extracting solution, namely crushing the black tea, extracting with hot water, and filtering to obtain the black tea extracting solution; 2) preparation of a composite pigment adsorbent: firstly preparing modified glycoprotein, modified cyclodextrin and modified chitosan, and then mixing the modified glycoprotein, the modified cyclodextrin and the modified chitosan according to a mass ratio of 1: (0.5-1): (0.5-1) to obtain the composite pigment adsorbent; 3) adsorption: adding the composite pigment adsorbent into the black tea extracting solution according to the addition amount which is 1-2% of the mass of the black tea extracting solution, mixing, adjusting the pH value to 4-5, stirring at 50 DEG C for 30 minutes, and centrifuging to obtain centrifugate; according to the method, complete black tea fragrance can be reserved, the color defect caused when the black tea is applied can be effectively overcome, the problems of liquid clarity and precipitation are effectively solved, and the application range of the black tea is greatly widened.

Description

Technical Field

[0001] The present invention belongs to the technical field of spice preparation, and particularly relates to a method for preparing spices using black tea as a raw material. Background Art

[0002] Spices are substances with specific aromas and flavors. They can not only enhance the sensory quality of products but also mask certain unpleasant odors and enhance the attractiveness of products. As a natural spice, tea spice is extracted from tea leaves and contains various volatile components and functional substances. Due to its unique aroma and health attributes, it has been widely used in industries such as food, beverage, cosmetics, and pharmaceuticals in recent years.

[0003] In existing methods for preparing tea spice, there are mainly solvent extraction method and steam distillation method. The solvent extraction method uses organic solvents (such as ethanol, ether, etc.) to extract aroma components from tea leaves. The volatile aromatic substances in tea leaves have a high solubility in the solvent. Through steps such as leaching, filtration, and concentration, tea spice can be obtained. However, this method will have solvent residues, affecting safety. The steam distillation method is a commonly used extraction technique. This method brings out the volatile components in tea leaves through distillation and then collects the distillate after condensation for preparation. However, its disadvantages such as high-temperature operation, low extraction efficiency, loss of water-soluble components, equipment corrosion, and high energy consumption limit its application in modern tea spice production.

[0004] For example, the patent application number CN201510787354.X discloses a method for preparing tea spice, which includes the following steps: First, ferment fresh tea leaves and then spread them evenly on the sieve plate in the distillation extraction tank for steam distillation. The water addition amount in the distillation extraction tank is 10 - 15 times the weight of the tea leaf raw material. The temperature in the distillation extraction tank is 90 - 100 °C, the distillation time is 2 - 3 h, and distillation extraction is carried out twice. Then, adjust the pH value of the distillate to 7 - 8 with 5% ammonia water by mass fraction, add 1 / 7 - 1 / 9 of the anhydrous CaCl2 by the mass of the tea leaf raw material under stirring, and finally obtain tea spice after nanofiltration.

[0005] In the above method for preparing tea spice, black tea is used as a raw material, and the effective components in black tea leaves are extracted by combining with the steam distillation method. And by adding anhydrous CaCl2 to remove tea polyphenols, tea spice with a higher purity is obtained. However, when preparing spices by this method, the pigment in black tea has a very high boiling point and enters the distillate during the distillation process, resulting in the spice liquid having a relatively deep color, which limits its application in transparent or light-colored foods; and although this method removes some tea polyphenols through CaCl2 treatment, there may still be a small amount of precipitates in the spice liquid, affecting the clarity and stability of the liquid.

[0006] Therefore, there is an urgent need for a new method for preparing spices, which can effectively solve the problems of liquid clarity and precipitation while retaining the natural aroma of tea, and improve the appearance quality and application range of the spices. Summary of the Invention

[0007] The object of the present invention is to provide a method for preparing spices using black tea as a raw material. This method can not only retain the complete fragrance of black tea but also effectively overcome the color defects brought about during its application, effectively solve the problems of liquid clarity and precipitation, and greatly improve its scope of application.

[0008] To achieve the above object, the present invention provides the following technical solution: A method for preparing spices using black tea as a raw material, comprising the following steps: 1) Preparation of black tea extract: Crush black tea to a particle size of 0.5 - 1.5 mm, extract with hot water at 80 - 90 °C for 10 - 15 minutes, and filter to obtain black tea extract; 2) Preparation of composite pigment adsorbent: First, prepare modified glycoprotein, modified cyclodextrin, and modified chitosan, and then mix the modified glycoprotein, modified cyclodextrin, and modified chitosan in a mass ratio of 1:(0.5 - 1):(0.5 - 1) to obtain a composite pigment adsorbent; 3) Adsorption: Add the composite pigment adsorbent to the black tea extract in an amount of 1 - 2% of the mass of the black tea extract, mix, adjust the pH to 4 - 5, stir at 50 °C for 30 minutes, and centrifuge to obtain a centrifugate; 4) Clarification treatment: Filter the centrifugate through a 0.45 μm microfiltration membrane to obtain a clarified liquid; 5) Concentration and formulation: Vacuum concentrate the clarified liquid and then add ethanol and mix evenly; 6) Sterilization and packaging: After filtering to remove impurities, sterilize with ultraviolet light and store in the dark to obtain the spices.

[0009] Preferably, when the modified glycoprotein, modified cyclodextrin, and modified chitosan are mixed, the mass ratio is 1:1:0.5.

[0010] Furthermore, the preparation method of the modified glycoprotein is as follows: Mix whey protein and glucose evenly in a mass ratio of 1:1 - 2, dissolve in water to prepare a solution with a concentration of 5 - 10%, heat at 60 - 80 °C for 1 - 2 h, then add trypsin and enzymatically hydrolyze at 50 - 60 °C for 1 h, adjust the pH to 6 - 7, filter and dry to obtain the modified glycoprotein.

[0011] Furthermore, the preparation method of the modified cyclodextrin is as follows: Dissolve β - cyclodextrin in water to prepare a solution with a concentration of 5 - 10%, add epichlorohydrin in an amount of 1 - 2% of the mass of β - cyclodextrin, react at 50 - 60 °C at pH 10 - 11 for 2 - 3 h, then adjust the pH to neutral, filter and dry to obtain the modified cyclodextrin.

[0012] Further, the preparation method of the modified chitosan is as follows: Dissolve chitosan in an acetic acid solution to prepare a solution with a concentration of 1%, then add glutaraldehyde according to 0.5 - 1% of the mass of chitosan, react at pH 5 - 6 for 2 h, filter and dry to obtain the modified chitosan.

[0013] Preferably, the extraction temperature of the black tea extract is 85°C and the time is 12 min.

[0014] Further, the rotation speed of the centrifugation is 4000 rpm and the time is 10 min.

[0015] Preferably, the addition amount of the composite pigment adsorbent is 1.5% of the mass of the black tea extract.

[0016] Further, the specific operation steps of step 5) are as follows: Vacuum concentrate the clarified liquid to 1 / 5 - 1 / 10 of the original volume, add ethanol, and mix evenly; the addition amount of ethanol is 5 - 10% of the volume of the concentrated liquid.

[0017] Further, the temperature of the vacuum concentration is 50 - 60°C and the vacuum degree is 0.08 - 0.1 MPa.

[0018] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. The process of the present invention is simple. By using a composite pigment adsorbent composed of modified glycoprotein, modified cyclodextrin and modified chitosan to treat the black tea extract, due to the Maillard reaction and enzymatic hydrolysis reaction during the preparation process, the modified glycoprotein contains a large number of amino groups, carboxyl groups and active groups, which can combine with black tea pigments (such as theaflavins and thearubigins) through electrostatic interaction and hydrogen bonds, enhance the binding ability with pigments to form insoluble complexes and remove the pigments; due to the cross-linking reaction between β-cyclodextrin and epichlorohydrin during the preparation process, the modified cyclodextrin forms a larger molecular weight and more cavity structures, which can include pigment molecules through hydrophobic interaction and reduce their solubility; the modified chitosan forms a network structure through the cross-linking of chitosan and glutaraldehyde, which can adsorb macromolecular pigments, and at the same time, its amino groups have electrostatic interaction with the anionic groups (such as phenolic hydroxyl groups) in the pigments, further enhancing the pigment removal effect; the modified proteoglycan mainly binds to the polar groups in the pigments, while the modified cyclodextrin mainly includes the hydrophobic groups in the pigments, and the modified chitosan adsorbs the pigments with macromolecular structures. Under the synergistic and cooperative action of these three, a wider range of pigment molecules can be covered, increasing the pigment removal rate to over 98%, greatly reducing the influence of pigments on the color of spices, and expanding the application range of spices; 2. In the present invention, the use of the composite pigment adsorbent can not only improve the adsorption of pigments and the removal rate of pigments, but also adsorb fine particles to further reduce the suspended matter in the solution. At the same time, combined with microfiltration membrane filtration treatment, it can further remove fine particles and incompletely removed pigment complexes, ensuring no precipitation during the storage and use of the product and significantly improving the clarity of the product. Detailed implementation manners

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment 1 This embodiment provides a method for preparing a spice using black tea as a raw material, including the following steps: 1) Preparation of black tea extract: 100 g of black tea is crushed to a particle size of 1 mm, extracted with hot water at 85 °C for 12 minutes, and filtered to obtain a black tea extract. 2) Preparation of the composite pigment adsorbent: a) Preparation of modified proteose: Whey protein and glucose are mixed evenly in a mass ratio of 1:1.5, dissolved in water to prepare a solution with a concentration of 8%, heated at 70 °C for 1.5 h, then added with trypsin and enzymolyzed at 55 °C for 1 h, adjusted to pH 6 - 7, filtered and dried to obtain modified proteose. b) Preparation of the modified cyclodextrin: β-cyclodextrin is dissolved in water to prepare a solution with a concentration of 8%, 1.5% of epichlorohydrin based on the mass of β-cyclodextrin is added, reacted at 55 °C under pH 10 - 11 for 2.5 h, then adjusted to neutral pH, filtered and dried to obtain modified cyclodextrin. c) The preparation method of the modified chitosan is as follows: Chitosan is dissolved in acetic acid solution to prepare a solution with a concentration of 1%, then 0.8% of glutaraldehyde based on the mass of chitosan is added, reacted at pH 5 - 6 for 2 h, filtered and dried to obtain modified chitosan. d) Compound: The modified proteose, modified cyclodextrin and modified chitosan are mixed in a mass ratio of 1:1:0.5 to obtain a composite pigment adsorbent. 3) Adsorption: The composite pigment adsorbent is added to the black tea extract at an addition amount of 1.5% of the mass of the black tea extract, mixed, adjusted to pH 4.5, stirred at 50 °C for 30 minutes, centrifuged at 4000 rpm for 10 min to obtain a centrifuged liquid. 4) Clarification treatment: The centrifuged liquid is filtered through a 0.45 μm microfiltration membrane to obtain a clarified liquid. 5) Concentration and blending: Concentrate the clarified liquid under vacuum at 55°C and 0.09 MPa to 1 / 8 of the original volume, add ethanol for blending, and mix evenly; the addition amount of ethanol is 8% of the volume of the concentrated liquid; 6) Sterilization and packaging: After filtering to remove impurities, sterilize with ultraviolet light and store in the dark to obtain the spice.

[0021] Example 2 This example provides a method for preparing a spice using black tea as a raw material, including the following steps: 1) Preparation of black tea extract: Crush 100 g of black tea to a particle size of 0.5 mm, extract with hot water at 80°C for 10 minutes, and filter to obtain the black tea extract; 2) Preparation of composite pigment adsorbent: a) Preparation of modified proteose: Mix whey protein and glucose evenly according to a mass ratio of 1:1, dissolve in water, prepare a solution with a concentration of 5%, heat at 60°C for 1 h, then add trypsin and enzymolyze at 50°C for 1 h, adjust the pH to 6 - 7, filter and dry to obtain the modified proteose; b) Preparation of the modified cyclodextrin: Dissolve β - cyclodextrin in water to prepare a solution with a concentration of 5%, add epichlorohydrin at 1% of the mass of β - cyclodextrin, react at 50°C for 2 h under pH 10 - 11, then adjust the pH to neutral, filter and dry to obtain the modified cyclodextrin; c) The preparation method of the modified chitosan is as follows: Dissolve chitosan in acetic acid solution to prepare a solution with a concentration of 1%, then add glutaraldehyde at 0.5% of the mass of chitosan, react at pH 5 - 6 for 2 h, filter and dry to obtain the modified chitosan; d) Blending: Mix the modified proteose, modified cyclodextrin and modified chitosan according to a mass ratio of 1:0.5:0.5 to obtain the composite pigment adsorbent; 3) Adsorption: Add the composite pigment adsorbent to the black tea extract at an addition amount of 1% of the mass of the black tea extract, mix, adjust the pH to 4.5, stir at 50°C for 30 minutes, centrifuge at 4000 rpm for 10 min to obtain the centrifuged liquid; 4) Clarification treatment: Filter the centrifuged liquid through a 0.45 μm microfiltration membrane to obtain the clarified liquid; 5) Concentration and blending: Concentrate the clarified liquid under vacuum at 50°C and 0.08 MPa to 1 / 5 of the original volume, add ethanol for blending, and mix evenly; the addition amount of ethanol is 5% of the volume of the concentrated liquid; 6) Sterilization and packaging: After filtering to remove impurities, sterilize with ultraviolet light and store in the dark to obtain the spice.

[0022] Example 3 This example provides a method for preparing a spice using black tea as a raw material, including the following steps: 1) Preparation of black tea extract: 100 g of black tea was crushed to a particle size of 1.5 mm, extracted with hot water at 90 °C for 15 minutes, and filtered to obtain black tea extract; 2) Preparation of composite pigment adsorbent: a) Preparation of modified proteose: Whey protein and glucose were mixed evenly according to a mass ratio of 1:1 - 2, dissolved in water, formulated into a solution with a concentration of 5 - 10%, heated at 60 - 80 °C for 1 - 2 h, then added with trypsin and enzymolyzed at 50 - 60 °C for 1 h, adjusted to pH 6 - 7, filtered and dried to obtain modified proteose; b) Preparation of the modified cyclodextrin: β - cyclodextrin was dissolved in water to formulate a solution with a concentration of 5 - 10%, epichlorohydrin was added at 1 - 2% of the mass of β - cyclodextrin, reacted at 50 - 60 °C at pH 10 - 11 for 2 - 3 h, then adjusted to neutral pH, filtered and dried to obtain modified cyclodextrin; c) Preparation method of the modified chitosan: Chitosan was dissolved in acetic acid solution to formulate a solution with a concentration of 1%, then glutaraldehyde was added at 0.5 - 1% of the mass of chitosan, reacted at pH 5 - 6 for 2 h, filtered and dried to obtain modified chitosan; d) Compound: Modified proteose, modified cyclodextrin and modified chitosan were mixed according to a mass ratio of 1:(0.5 - 1):(0.5 - 1) to obtain composite pigment adsorbent; 3) Adsorption: The composite pigment adsorbent was added to the black tea extract at an addition amount of 2% of the mass of the black tea extract, mixed, adjusted to pH 4.5, stirred at 50 °C for 30 minutes, centrifuged at 4000 rpm for 10 min to obtain centrifuged liquid; 4) Clarification treatment: The centrifuged liquid was filtered through a 0.45 μm microfiltration membrane to obtain clarified liquid; 5) Concentration and blending: The clarified liquid was vacuum - concentrated to 1 / 10 of the original volume at 60 °C and 0.1 MPa, ethanol was added for blending and mixed evenly; the addition amount of ethanol was 10% of the volume of the concentrated liquid; 6) Sterilization and packaging: After filtering to remove impurities, it was sterilized by ultraviolet light and stored in the dark to obtain the spice.

[0023] Comparative Example 1 The difference between this comparative example and Example 1 is that in step 3), direct adsorption with activated carbon was used: Activated carbon was added to the black tea extract at an addition amount of 2% of the mass of the black tea extract, mixed, stirred at 50 °C for 30 minutes, centrifuged at 4000 rpm for 10 min to obtain centrifuged liquid.

[0024] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: In step 3), only β-cyclodextrin adsorption is used: The modified β-cyclodextrin is added to the black tea extract at an addition amount of 2% of the mass of the black tea extract and mixed, the pH is adjusted to 4.5, stirred at 50 °C for 30 minutes, and centrifuged at 4000 rpm for 10 min to obtain the centrifugate.

[0025] Comparative Example 3 The difference between this comparative example and Example 1 is as follows: In step 3), only modified chitosan adsorption is used: The modified chitosan is added to the black tea extract at an addition amount of 2% of the mass of the black tea extract and mixed, the pH is adjusted to 4.5, stirred at 50 °C for 30 minutes, and centrifuged at 4000 rpm for 10 min to obtain the centrifugate.

[0026] Comparative Example 4 The difference between this comparative example and Example 1 is as follows: In step 3), only modified glycoprotein adsorption is used: The modified glycoprotein is added to the black tea extract at an addition amount of 2% of the mass of the black tea extract and mixed, the pH is adjusted to 4.5, stirred at 50 °C for 30 minutes, and centrifuged at 4000 rpm for 10 min to obtain the centrifugate.

[0027] The present invention tested the pigment removal rate, aroma retention rate, clarity (light transmittance) and precipitation of the fragrances prepared in Examples 1-3 and Comparative Examples 1-4, and applied the fragrances prepared in each treatment group to transparent tea beverages. The comprehensive sensory evaluation results of the tea beverages are shown in the following table: Table 1 Performance test results

[0028] From the above performance test results, it can be seen that the pigment removal rates and aroma retention rates of Examples 1-3 are both higher than 94%, and there is no precipitation, and the application effect is excellent. In particular, the comprehensive performance of Example 1 is the most prominent. This is mainly because the modified protein sugar mainly binds to the polar groups in the pigment, while the modified cyclodextrin mainly includes the hydrophobic groups in the pigment, and the modified chitosan adsorbs the pigment with a macromolecular structure. Under the synergistic effect of these three, a wider range of pigment molecules can be covered, not only increasing the pigment removal rate to more than 98%, but also being able to adsorb fine particles, further reducing the suspended matter in the solution; at the same time, combined with microfiltration membrane filtration treatment, it can further remove fine particles and pigment complexes that have not been completely removed, significantly improving the clarity of the product and making the prepared fragrance clear and without precipitation, thereby improving its application value.

[0029] In Comparative Example 1, the type of adsorbent was changed, and activated carbon was used as the adsorbent. It can be seen that the pigment removal rate, aroma retention rate, precipitation and application effect all decreased, proving that the composite pigment adsorbent scheme has an important impact on pigment removal, aroma retention and clarity; In Comparative Examples 2-4, no composite pigment adsorbent was used, and only a single modified adsorbent was used. It can be seen from the results that the pigment removal rate, aroma retention rate, precipitation, and application effect all decreased, which proves that under the synergistic effect of modified proteose, modified cyclodextrin, and modified chitosan, the problems of black tea pigment and spice clarity can be effectively solved, greatly expanding the scope of use of spices.

[0030] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle described in the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a spice using black tea as a raw material, characterized in that, It includes the following steps: 1) Preparation of black tea extract: Crush black tea to a particle size of 0.5 - 1.5 mm, extract it with hot water at 80 - 90 °C for 10 - 15 minutes, and filter to obtain black tea extract; 2) Preparation of composite pigment adsorbent: First, prepare modified glycoprotein, modified cyclodextrin, and modified chitosan, and then mix the modified glycoprotein, modified cyclodextrin, and modified chitosan in a mass ratio of 1:(0.5 - 1):(0.5 - 1) to obtain a composite pigment adsorbent; 3) Adsorption: Add the composite pigment adsorbent to the black tea extract at an addition amount of 1 - 2% of the mass of the black tea extract, mix, adjust the pH to 4 - 5, stir at 50 °C for 30 minutes, and centrifuge to obtain a centrifugate; 4) Clarification treatment: Filter the centrifugate through a 0.45 μm microfiltration membrane to obtain a clarified liquid; 5) Concentration and formulation: Vacuum - concentrate the clarified liquid and then add ethanol and mix evenly; 6) Sterilization and packaging: After filtering to remove impurities, sterilize with ultraviolet light and store in the dark to obtain a spice.

2. The method for preparing a spice using black tea as a raw material according to claim 1, wherein The mass ratio of the modified glycoprotein, modified cyclodextrin, and modified chitosan during mixing is 1:1:0.

5.

3. A method for preparing a spice using black tea as a raw material according to claim 2, characterized in that, The preparation method of the modified glycoprotein is as follows: Mix whey protein and glucose evenly in a mass ratio of 1:(1 - 2), dissolve them in water to prepare a solution with a concentration of 5 - 10%, heat at 60 - 80 °C for 1 - 2 h, then add trypsin and enzymatically hydrolyze at 50 - 60 °C for 1 h, adjust the pH to 6 - 7, filter and dry to obtain modified glycoprotein.

4. A method for preparing a spice using black tea as a raw material according to claim 1, characterized in that, The preparation method of the modified cyclodextrin is as follows: Dissolve β - cyclodextrin in water to prepare a solution with a concentration of 5 - 10%, add epichlorohydrin at 1 - 2% of the mass of β - cyclodextrin, react at 50 - 60 °C at pH 10 - 11 for 2 - 3 h, then adjust the pH to neutral, filter and dry to obtain modified cyclodextrin.

5. A method for preparing a spice using black tea as a raw material according to claim 1, characterized in that, The preparation method of the modified chitosan is as follows: Dissolve chitosan in an acetic acid solution to prepare a solution with a concentration of 1%, then add glutaraldehyde at 0.5 - 1% of the mass of chitosan, react at pH 5 - 6 for 2 h, filter and dry to obtain modified chitosan.

6. A method for preparing a spice using black tea as a raw material according to claim 1, wherein, The extraction temperature of the black tea extract is 85 °C and the time is 12 min.

7. A method for preparing a spice using black tea as a raw material according to claim 1, characterized in that, The rotation speed of the centrifugation is 4000 rpm and the time is 10 min.

8. A method for preparing a spice using black tea as a raw material according to claim 1, characterized in that, The addition amount of the composite pigment adsorbent is 1.5% of the mass of the black tea extract.

9. A method for preparing a spice using black tea as a raw material according to claim 1, characterized in that, The specific operation steps of step 5) are as follows: Vacuum - concentrate the clarified liquid to 1 / 5 - 1 / 10 of the original volume, add ethanol and mix evenly; the addition amount of ethanol is 5 - 10% of the volume of the concentrated liquid.

10. A method for preparing a spice using black tea as a raw material according to claim 9, characterized in that, The temperature of the vacuum concentration is 50 - 60 °C and the vacuum degree is 0.08 - 0.1 MPa.

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