Preparation and application of an orange-red pigment

Abstract

This invention discloses the preparation and application of an orange-red pigment. By co-heating four theaflavins monomers or mixtures thereof with a mixture of amino acids such as L-theanine and glucose, the reaction product solution, after dilution, shows an increase in the a value and a decrease in the b value. The reaction solution, after release, is generally orange-red, gradually turning peach-pink with increasing dilution. This invention utilizes flavor substances abundant in tea leaves to simply and quickly synthesize food-grade peach-pink to orange-red solutions. These solutions can be used as coloring and flavoring additives for food and beverages, and also possess certain health benefits, indicating a promising market prospect.

Description

Technical Field

[0001] This invention relates to the field of natural pigment development technology, specifically to the preparation and application of an orange-red pigment. Background Technology

[0002] Tea is a widely consumed beverage, possessing not only unique flavor characteristics but also significant health benefits, containing many chemical substances with flavor profiles and physiological functions. Black tea, as a fermented tea, produces theaflavins and thearubigins through enzymatic oxidation during processing, which are used as natural pigments and have considerable application prospects and development potential. In addition, tea contains many oxidation products and small molecules generated during processing that possess unique flavor and health benefits.

[0003] Theaflavins are water-soluble natural pigments, primarily composed of four theaflavin monomers: theaflavin (TF1), theaflavin-3-gallate (TF2a), theaflavin-3'-gallate (TF2b), and theaflavin-3,3'-digallate (TF3). During black tea processing, different catechin monomers can generate different theaflavin monomers. The aqueous solutions of these four theaflavin monomers exhibit an orange-yellow color and possess antioxidant, antibacterial, and lipid-lowering activities. They belong to the tea pigment family, along with thearubigins and theabrownins.

[0004] Amino acids and glucose are widely present in tea. Theanine is a unique and abundant free amino acid found in tea, while glucose is a major component of soluble sugars. These two components provide the material basis for the freshness and sweetness of tea. Theanine helps alleviate the bitterness of tea and also has anti-inflammatory, weight-loss, lipid-lowering, and antioxidant functions. Glucose, on the other hand, is the main soluble sugar in tea and one of the main sweet substances, contributing significantly to the sweet and mellow taste of tea.

[0005] Under high temperatures, carbonyl-containing sugars can undergo Maillard reactions with amino acids or proteins, producing brownish-black substances that affect the color, taste, and aroma of food. During the drying process of black tea, the Maillard reaction products and intermediates formed from the relatively high levels of glucose and theanine in the tea leaves influence the color and aroma of the tea liquor. Whether the theaflavins formed before drying participate in the drying process and undergo co-heating reactions with the Maillard reaction substrates, thus affecting the red color of the black tea liquor, has not yet been studied.

[0006] Currently, simulated reactions are widely used in the study of reaction mechanisms. They can quickly analyze the reaction process and changes between substances, and help to quickly elucidate the effects on flavor characteristics such as color, taste, and aroma. They play an important role in both basic research and actual production. The reaction products generated through simulated reactions have promising application prospects.

[0007] Theaflavins, theanine, and glucose are flavor compounds that make up a large proportion of tea. During processing such as drying, they produce a variety of colors, aromas, and flavors. Their mixed solution is bright yellow. However, this invention generates reaction products that are pink and orange-red depending on the concentration through heat treatment. Summary of the Invention

[0008] The purpose of this invention is to propose a method for preparing and applying an orange-red pigment. This method uses simple raw materials, is convenient and quick, and can rapidly prepare a food-grade solution containing an orange-red pigment. It can be used to enhance the color and flavor of food and beverages, and has potential health benefits and flavor-enhancing effects.

[0009] To achieve the above objectives, the present invention provides a method for preparing an orange-red pigment, comprising the following steps:

[0010] (1) Preparation of reactants: Obtain theaflavin monomers or mixtures, amino acids and glucose in pure form;

[0011] (2) Use theaflavin monomers or mixtures, amino acids and glucose, add pure water, vortex until completely dissolved, and obtain the solution before the reaction;

[0012] (3) Add a magnetic stir bar to the solution before the reaction, and react under heating and stirring conditions to obtain an orange-red pigment.

[0013] Further, the purity of the theaflavins monomer or mixture in step (1) is 75-100%; the purity of the amino acids is 75-100%; and the purity of the glucose is 75-100%.

[0014] Further, the theaflavin monomers or mixtures mentioned in step (1) include one or more of TF1, TF2a, TF2b, and TF3.

[0015] Furthermore, the mixing ratio of the theaflavins can be arbitrary.

[0016] Furthermore, the amino acids mentioned in step (1) include, but are not limited to: L-theanine, glutamic acid, monosodium glutamate, aspartic acid, glycine, and alanine.

[0017] Further, in step (2), the mass ratio of glucose, theaflavins monomer or mixture, and amino acids is 0:1:20 or 20-30:0.5-1:20-25.

[0018] Further, the heating and stirring parameters in step (3) are: rotation speed > 200 rpm, heating temperature > 80℃, and heating time > 30 min.

[0019] The present invention also discloses an orange-red pigment prepared according to any of the above preparation methods.

[0020] The present invention also discloses the application of the above-mentioned orange-red pigment in food processing and production.

[0021] The beneficial effects of this invention are as follows:

[0022] The present invention has a clearly defined substrate and a simple reaction procedure. The reaction product, which is orange-red in color, can be generated by heating the substrate mixture. It is stable and has potential health effects and flavor-enhancing capabilities. Attached Figure Description

[0023] Figure 1 The result is the color of the reaction solution;

[0024] Figure 2 The results are the visible light spectrum of the reaction solution;

[0025] Figure 3 This is a sensory evaluation chart for flavor. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0027] Example 1

[0028] Preparation of an orange-red pigment:

[0029] (1) Mix equal amounts of four theaflavin monomers TF1, TF2a, TF2b and TF3 to form a theaflavin mixture.

[0030] (2) Accurately weigh 1 mg of theaflavins mixture, 20 mg of L-theanine, and 20 mg of glucose as group A, and accurately weigh 1 mg of theaflavins mixture and 20 mg of L-theanine as group B. Add 200 μL of pure water to each, vortex for 1 min to mix, and this is the solution before the reaction. Add 15 mL of pure water for color measurement. The color and chromaticity values ​​of the solution before the reaction are as follows: Figure 1 As shown in Table 1.

[0031] (3) Add a magnetic stir bar to the solution before the reaction, heat in a 100℃ water bath at 200 rpm for 60 min, and immediately cool to obtain the solution after the reaction. Add 15 mL of pure water for color measurement. The results of the color, chromaticity value, and visible light absorption spectrum of the solution after the reaction are as follows: Figure 1 , Figure 2 As shown in Table 1.

[0032] Example 2

[0033] Preparation of an orange-red pigment:

[0034] (1) Weigh 1 mg of TF1, TF2a, TF2b and TF3 monomers respectively, and add 20 mg of L-theanine to each.

[0035] (2) Add 200 μL of pure water to each, vortex for 1 min to mix, add a magnetic stir bar, heat in a 100℃ water bath at 200 rpm for 60 min, cool immediately to obtain the reaction solution, perform α-glucosidase activity determination and calculate IC50 value. The determination results are shown in Table 2.

[0036] Example 3

[0037] (1) Mix equal amounts of four theaflavin monomers TF1, TF2a, TF2b and TF3 to form a theaflavin mixture.

[0038] (2) Accurately weigh 1 mg of theaflavins mixture and 20 mg of L-theanine, add 200 μL of pure water, vortex for 1 min to mix well, and obtain the solution before reaction. Perform sensory evaluation to obtain the taste score.

[0039] (3) Add a magnetic stir bar to the solution, heat in a 100°C water bath at 200 rpm for 60 min, then immediately cool to obtain the reaction solution. Perform sensory evaluation to obtain a taste score, and the score results are as follows: Figure 3 As shown.

[0040] The characteristics of the obtained reaction products are as follows:

[0041] 1) The product after the reaction is orange-red in color, and gradually turns into peach pink as the dilution ratio increases.

[0042] 2) The light source conditions and colorimeter parameters used for color observation are D65 light source and 10° observation angle.

[0043] 3) After the reaction, the a value of the solutions in both groups A and B increased significantly. The diluted solutions were orange-red and pinkish-red, which were significantly different from the colors before the reaction. This indicates that red pigment substances were generated and can be used as color additives.

[0044] 4) The comparison results between Group A and Group B show that the addition of glucose can promote the generation of red pigment substances, which increases the a value of the solution and has a better effect on enhancing the red color intensity.

[0045] 5) The product after the reaction has a good inhibitory effect on α-glucosidase activity, as detailed in Table 2.

[0046] 6) The sweetness and umami scores of the product after the reaction were improved, while the bitterness and astringency were reduced.

[0047] Table 1. Results of colorimetric determination of Lab and LCH values ​​for the reaction solution using a colorimeter.

[0048]

[0049] Note: Lab represents: brightness (0-100), green (-100), red (+100), blue (-100), and yellow (+100) respectively.

[0050] LCH represent: Brightness (0-100), Saturation (0-100), and Hue (0°-90°-180°-270°-360°).

[0051] Table 2. Inhibitory capacity of α-glucosidase activity

[0052]

[0053]

[0054] According to Table 1 and Figure 1 Figure 2 The results show that a mixture of theaflavins, L-theanine, and glucose, or just a mixture of theaflavins and L-theanine in aqueous solution, can rapidly produce an orange-red solution under stirring and heating conditions. Sensory evaluation and colorimetric observation of the solution before and after the reaction reveal that the theaflavins and theanine reduce the content of the yellow substance, producing a red substance. After adding glucose, the amount of red substance produced increases, the solution's a value rises, and it exhibits a distinct red color.

[0055] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing an orange-red pigment, comprising: (1) Preparation of reactants: Obtain 1 mg of theaflavins monomer or mixture, 20 mg of L-theanine and 20 mg of pure glucose; (2) Use theaflavin monomer or mixture, L-theanine and glucose, add pure water, vortex until completely dissolved, and obtain the solution before reaction; (3) Add a magnetic stir bar to the solution before the reaction, and react under heating and stirring conditions to obtain an orange-red pigment.

2. The method according to claim 1, characterized in that: The purity of the theaflavins monomers or mixtures mentioned in step (1) is 75-100%; The purity of the L-theanine is 75-100%; The purity of the glucose is 75-100%.

3. The method according to claim 1, wherein: The theaflavins monomers or mixtures mentioned in step (1) include one or more of TF1, TF2a, TF2b, and TF3.

4. An orange-red pigment prepared by any one of the preparation methods according to claims 1 to 3.

5. The application of the orange-red pigment according to claim 4 in food processing and production.

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