A blueberry puree prepared by cryogenic grinding and oxidation isolation

Abstract

The invention relates to the technical field of blueberry puree preparation, and relates to a blueberry puree prepared based on cryogenic grinding, oxidation and isolation. The blueberry puree comprises the following components in parts by weight: 90-100 parts by weight of blueberries, 0.1-0.5 parts by weight of a composite stabilizer, 1-5 parts by weight of a honey protective agent, 0.03-0.05 parts by weight of an L-cysteinease inhibitor, and 0.3-0.7 parts by weight of a citric acid buffer. The composite stabilizer is obtained by mixing phytic acid, sodium pyrophosphate, and modified catechin in a ratio of 1:0.2-0.6:1-3, and the modified catechin is prepared by a glycosylation reaction of catechin and rhamnose in the presence of a rhamnosyltransferase catalyst. The composite stabilizer is used to improve the antioxidant capacity and the ability to stabilize active components in the blueberry puree preparation process, thereby extending the shelf life. At the same time, the cryogenic grinding, oxidation and isolation preparation technology is used to retain the nutrients and active substances in the blueberries to the greatest extent, thereby ensuring the high quality of the product.

Description

Technical Field

[0001] The invention relates to the technical field of blueberry puree preparation, in particular to a blueberry puree prepared based on low-temperature grinding, oxidation and isolation. Background Art

[0002] Blueberry puree is a liquid product made from fresh or frozen blueberries. It is obtained by crushing, squeezing or grinding the blueberries to extract the juice. Blueberry puree is rich in nutrients, mainly containing protein, vitamins and minerals. It also contains some special nutrients such as anthocyanins, organic acids, flavonoids and polysaccharides, which have the effects of improving antioxidant capacity, enhancing human immunity and improving vision.

[0003] However, in the traditional blueberry puree preparation process, oxygen is easily brought into direct contact with the puree, which can cause browning of the pulp color, deterioration of flavor, and oxidation loss of nutrients, which not only affects the appearance and taste of the product, but also reduces its nutritional value and preservation performance. In addition, during the grinding process, the active components in the blueberry are easily degraded or transformed, resulting in a large amount of loss of the active components due to their inability to exist stably. In view of this, a blueberry puree prepared based on low-temperature grinding and oxidation isolation is provided. Summary of the Invention

[0004] The object of the present invention is to provide a blueberry puree prepared by cryogenic grinding and oxidation isolation, so as to solve the problem of poor stability of active components in the preparation process of blueberry puree proposed in the above background art.

[0005] To achieve the above objectives, the present invention provides a blueberry puree prepared by cryogenic grinding and oxidation isolation, comprising the following components in parts by weight: 90-100 parts by weight of blueberries, 0.1-0.5 parts by weight of a composite stabilizer, 1-5 parts by weight of honey, 0.03-0.05 parts by weight of L-cysteine, and 0.3-0.7 parts by weight of a citric acid buffer solution, wherein the composite stabilizer is a mixture of phytic acid, sodium pyrophosphate, and modified catechins in a ratio of 1:0.2-0.6:1-3, and the modified catechins are prepared by a glycosylation reaction of catechins and rhamnose in the presence of a rhamnosyltransferase catalyst.

[0006] As a further improvement of this technical solution, the specific preparation method of the composite stabilizer is as follows:

[0007] Catechin and rhamnose are dissolved in a citric acid buffer solution, and then rhamnosyltransferase is added. The mixed solution is placed in a constant temperature water bath for reaction. After the reaction is completed, the enzyme activity is terminated by heating to 80-100°C. The enzyme and other insoluble substances are then removed by a centrifuge to obtain a modified catechin. Subsequently, phytic acid and sodium pyrophosphate are added to the modified catechin in sequence, and stirring is continued until uniformly dispersed to obtain a composite stabilizer.

[0008] Catechins are a class of natural polyphenol compounds that are mainly found in a variety of plants, especially tea leaves. They are one of the important bioactive ingredients in tea leaves such as green tea, black tea and oolong tea. Catechins have various health benefits, such as antioxidant effects, which can help scavenge free radicals in the body and reduce oxidative stress, thereby protecting cells from damage. When added during the preparation of blueberry puree, they can protect the active components of the blueberry puree. At the same time, they also have a certain metal chelating ability, which can form stable complexes with metal ions such as iron ions and copper ions, inhibiting the ability of these metal ions to catalyze the production of free radicals, thereby protecting the components in the blueberry puree; rhamnose is a monosaccharide with the chemical name 6-deoxy-L-mannose and the molecular formula C6H 12 O5 is a naturally occurring sugar that is widely distributed in plant polysaccharides, glycosides, plant gums and bacterial polysaccharides in nature. Catechin is the glycosylated substrate, and rhamnose is the glycosyl donor. Rhamnosyltransferase first recognizes and binds to a specific position of the catechin molecule, which is usually the hydroxyl group on the catechin molecule. The enzyme catalyzes the transfer of rhamnose from its donor to the catechin molecule through the catalytic action of its active site, forming a glycosidic bond. The glycosylation reaction of catechin improves the water solubility, antioxidant properties and stability of catechin, thereby improving the protection of the active components of blueberry puree.

[0009] As a naturally occurring polyphosphate, phytate can stabilize cell structure by binding to metal ions, preventing the activation of nucleases and thus inhibiting nucleic acid degradation. It also has antioxidant properties, which can help prevent oxidation reactions catalyzed by polyphenol oxidase (PPO) in blueberries, thereby reducing browning. Because it is itself a natural nutritional supplement, it can also increase the nutritional value of the product. Sodium pyrophosphate is an inorganic compound with the chemical formula Na4P2O7. It is a commonly used chelating agent that can chelate metal ions, help stabilize the system and reduce oxidation reactions. Composite stabilizers can exert the synergistic effect among phytate, sodium pyrophosphate and modified catechins, effectively protecting the active ingredients in the blueberry puree from the influence of the external environment and maintaining its freshness and nutritional value.

[0010] As a further improvement of the present technical solution, the pH value of the citric acid buffer solution is in the range of 5-6.

[0011] As a further improvement of the technical solution, the water bath temperature for the glycosylation reaction of catechin and rhamnose in the presence of rhamnosyltransferase catalyst is 30-40° C., and the reaction time is 1-2 h.

[0012] As a further improvement of the technical solution, the mass ratio of catechin to rhamnose is 1:4-8.

[0013] As a further improvement of the present technical solution, the concentration of the rhamnosyltransferase in the mixed solution of catechin and rhamnose is 1-5 U / mL.

[0014] As a further improvement of the present technical solution, the centrifuge parameters are set to 3000-4000 rpm / min, and the centrifugation time is 5-10 min.

[0015] As a further improvement of this technical solution, the specific preparation method of the blueberry puree is as follows:

[0016] After soaking the blueberry fruits in clean water, they are sprayed and rinsed to remove impurities attached to the surface of the blueberry fruits. The cleaned blueberry fruits are framed and frozen in a freezer. The frozen blueberries are placed in a low-temperature grinder, and a composite stabilizer, honey, L-cysteine, and citric acid buffer are added in sequence. The inert gas nitrogen is filled in, the parameters are set, the grinder is turned on, and grinding is performed. The slurry obtained by grinding is filtered to remove pomace and solid impurities to obtain blueberry puree.

[0017] The sugar in honey can wrap around proteins or nucleic acids, forming a physical barrier, reducing their direct contact with the external environment, thereby reducing physical damage. In addition, the presence of sugar in honey can reduce the interaction between proteins, avoid aggregation and precipitation, and at the same time, sugar can combine with water molecules, reducing the interaction between water molecules and the surface of proteins or nucleic acids, reducing the degree of hydration, thereby reducing protein denaturation and nucleic acid hydrolysis.

[0018] L-cysteine ​​contains a sulfur group (-SH). This sulfur group is reducing and can react with free radicals to prevent the occurrence of free radical chain reactions, thereby playing an antioxidant role. At the same time, L-cysteine ​​can bind to the active site in polyphenol oxidase (PPO), thereby inhibiting the activity of the enzyme, preventing the oxidation reaction catalyzed by polyphenol oxidase (PPO), and reducing browning.

[0019] Since the stability of nucleic acids often depends on the pH value, adding a buffer solution can absorb or release hydrogen ions (H +) or hydroxide ions (OH-) to help maintain the pH value in the system within a narrow range and prevent nucleic acid degradation. This is because polyphenol oxidase (PPO) is one of the key enzymes that causes browning of blueberry puree. At the same time, it provides a suitable environment to maintain the function and structural integrity of proteins.

[0020] As a further improvement of the technical solution, the blueberries are frozen in the freezer at a temperature of -20°C to -15°C, and the freezing time is 1-3 hours.

[0021] As a further improvement of the technical solution, the low-temperature grinding machine is set with a parameter temperature of -10-0°C, a grinding speed of 10000-15000 rpm / min, and a grinding time of 30-60s.

[0022] Cryogenic grinding and oxidation isolation technology is a technology that performs sample grinding and oxidation isolation under low temperature conditions. This method helps protect the sample from structural changes caused by thermal damage and mechanical stress. In this process, the sample is rapidly frozen to achieve a low temperature environment. Subsequently, the sample is physically ground by grinding media in a frozen state to achieve the purpose of reducing particle size, mixing or separating components. The advantages of cryogenic grinding include effectively inhibiting nucleic acid degradation, retaining protein activity, reducing sample volatilization, and improving grinding effect and efficiency, especially for samples with high hardness or strong toughness. In addition, cryogenic grinding also helps to prepare an oxidation isolation layer because low temperature can reduce the chemical reaction rate, thereby maintaining the chemical purity and structural integrity of the material during the grinding process.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The blueberry puree prepared based on low-temperature grinding and oxidation isolation uses a composite stabilizer prepared from modified catechins, phytic acid, and sodium pyrophosphate, which improves the antioxidant capacity and ability to stabilize active components during the preparation of the blueberry puree. The stabilizer can effectively protect the active components in the blueberry puree, improve their stability, and extend their shelf life. Furthermore, the low-temperature grinding and oxidation isolation preparation technology is used to effectively inhibit nucleic acid degradation, retain protein activity, reduce sample volatilization, and improve grinding effect and efficiency, thereby maximally retaining the nutrients and active substances in the blueberries and ensuring the high quality of the product. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] A blueberry puree prepared based on cryogenic grinding, oxidation and isolation comprises the following components in parts by weight: 90-100 parts by weight of blueberries, 0.1-0.5 parts by weight of a composite stabilizer, 1-5 parts by weight of honey, 0.03-0.05 parts by weight of L-cysteine, and 0.3-0.7 parts by weight of a citric acid buffer. The composite stabilizer is obtained by mixing phytic acid, sodium pyrophosphate, and modified catechin in a ratio of 1:0.2-0.6:1-3, and the modified catechin is prepared by a glycosylation reaction between catechin and rhamnose using a rhamnosyltransferase catalyst.

[0027] Example 1: In this example, the specific preparation method of the blueberry puree prepared based on cryogenic grinding, oxidation and isolation is as follows:

[0028] Prepare the following components: 100 parts by weight of blueberries, 0.3 parts by weight of a composite stabilizer, 1 part by weight of honey, 0.03 parts by weight of L-cysteine, and 0.5 parts by weight of a citric acid buffer, wherein the composite stabilizer is a mixture of phytic acid, sodium pyrophosphate, and modified catechin in a ratio of 1:0.2:1, the mass ratio of catechin to rhamnose is 1:6, the concentration of rhamnosyltransferase in the mixed solution of catechin and rhamnose is 3 U / mL, and the pH range of the citric acid buffer is 5;

[0029] Catechin and rhamnose were dissolved in a citric acid buffer solution and then rhamnosyltransferase was added. The mixed solution was placed in a constant temperature water bath, and the reaction temperature was set at 30°C for 2 hours. After the reaction, the enzyme activity was terminated by heating to 100°C. The enzyme and other insoluble substances were then removed by centrifugation at a speed of 3000 rpm / min and a centrifugation time of 5 minutes to obtain modified catechin. Inositol hexaphosphate and sodium pyrophosphate were then added to the modified catechin in sequence, and stirring was continued until uniformly dispersed to obtain a composite stabilizer.

[0030] After soaking the blueberry fruits in clean water, they are sprayed and rinsed to remove impurities attached to the surface of the blueberry fruits. After cleaning, the blueberry fruits are framed and placed in a freezer at -20°C for 2 hours. The frozen blueberries are placed in a low-temperature grinder, and a composite stabilizer, honey, L-cysteine, and citric acid buffer are added in sequence. The inert gas nitrogen is filled in, and the parameter temperature is set to -10°C, the grinding speed is 10000 rpm / min, and the grinding time is 30 seconds. The grinder is turned on and grinding is performed. The slurry obtained by grinding is filtered to remove pomace and solid impurities to obtain blueberry puree.

[0031] Example 2: In this example, the specific preparation method of the blueberry puree prepared based on cryogenic grinding, oxidation and isolation is as follows:

[0032] Prepare the following components: 100 parts by weight of blueberries, 0.3 parts by weight of a composite stabilizer, 1 part by weight of honey, 0.03 parts by weight of L-cysteine, and 0.5 parts by weight of a citric acid buffer, wherein the composite stabilizer is a mixture of phytic acid, sodium pyrophosphate, and modified catechin in a ratio of 1:0.4:2, the mass ratio of catechin to rhamnose is 1:6, the concentration of rhamnosyltransferase in the mixed solution of catechin and rhamnose is 3 U / mL, and the pH range of the citric acid buffer is 5;

[0033] Catechin and rhamnose were dissolved in a citric acid buffer solution and then rhamnosyltransferase was added. The mixed solution was placed in a constant temperature water bath, and the reaction temperature was set at 30°C for 2 hours. After the reaction, the enzyme activity was terminated by heating to 100°C. The enzyme and other insoluble substances were then removed by centrifugation at a speed of 3000 rpm / min and a centrifugation time of 5 minutes to obtain modified catechin. Inositol hexaphosphate and sodium pyrophosphate were then added to the modified catechin in sequence, and stirring was continued until uniformly dispersed to obtain a composite stabilizer.

[0034] After soaking the blueberry fruits in clean water, they are sprayed and rinsed to remove impurities attached to the surface of the blueberry fruits. After cleaning, the blueberry fruits are framed and placed in a freezer at -20°C for 2 hours. The frozen blueberries are placed in a low-temperature grinder, and a composite stabilizer, honey, L-cysteine, and citric acid buffer are added in sequence. The inert gas nitrogen is filled in, and the parameter temperature is set to -10°C, the grinding speed is 10000 rpm / min, and the grinding time is 30 seconds. The grinder is turned on and grinding is performed. The slurry obtained by grinding is filtered to remove pomace and solid impurities to obtain blueberry puree.

[0035] Example 3: In this example, the specific preparation method of the blueberry puree prepared based on cryogenic grinding, oxidation and isolation is as follows:

[0036] Prepare the following components: 100 parts by weight of blueberries, 0.3 parts by weight of a composite stabilizer, 1 part by weight of honey, 0.03 parts by weight of L-cysteine, and 0.5 parts by weight of a citric acid buffer, wherein the composite stabilizer is a mixture of phytic acid, sodium pyrophosphate, and modified catechin in a ratio of 1:0.6:3, the mass ratio of catechin to rhamnose is 1:6, the concentration of rhamnosyltransferase in the mixed solution of catechin and rhamnose is 3 U / mL, and the pH range of the citric acid buffer is 5;

[0037] Catechin and rhamnose were dissolved in a citric acid buffer solution and then rhamnosyltransferase was added. The mixed solution was placed in a constant temperature water bath, and the reaction temperature was set at 30°C for 2 hours. After the reaction, the enzyme activity was terminated by heating to 100°C. The enzyme and other insoluble substances were then removed by centrifugation at a speed of 3000 rpm / min and a centrifugation time of 5 minutes to obtain modified catechin. Inositol hexaphosphate and sodium pyrophosphate were then added to the modified catechin in sequence, and stirring was continued until uniformly dispersed to obtain a composite stabilizer.

[0038] After soaking the blueberry fruits in clean water, they are sprayed and rinsed to remove impurities attached to the surface of the blueberry fruits. After cleaning, the blueberry fruits are framed and placed in a freezer at -20°C for 2 hours. The frozen blueberries are placed in a low-temperature grinder, and a composite stabilizer, honey, L-cysteine, and citric acid buffer are added in sequence. The inert gas nitrogen is filled in, and the parameter temperature is set to -10°C, the grinding speed is 10000 rpm / min, and the grinding time is 30 seconds. The grinder is turned on and grinding is performed. The slurry obtained by grinding is filtered to remove pomace and solid impurities to obtain blueberry puree.

[0039] Example 4: In this example, the specific preparation method of the blueberry puree prepared based on cryogenic grinding, oxidation and isolation is as follows:

[0040] Prepare the following components: 90 parts by weight of blueberries, 0.3 parts by weight of a composite stabilizer, 5 parts by weight of honey, 0.05 parts by weight of L-cysteine, and 0.7 parts by weight of a citric acid buffer, wherein the composite stabilizer is a mixture of phytic acid, sodium pyrophosphate, and modified catechin in a ratio of 1:0.6:3, the mass ratio of catechin to rhamnose is 1:6, the concentration of rhamnosyltransferase in the mixed solution of catechin and rhamnose is 5 U / mL, and the pH range of the citric acid buffer is 5;

[0041] Catechin and rhamnose were dissolved in a citric acid buffer solution and then rhamnosyltransferase was added. The mixed solution was placed in a constant temperature water bath, and the reaction temperature was set at 30°C for 2 hours. After the reaction, the enzyme activity was terminated by heating to 100°C. The enzyme and other insoluble substances were then removed by centrifugation at a speed of 3000 rpm / min and a centrifugation time of 5 minutes to obtain modified catechin. Inositol hexaphosphate and sodium pyrophosphate were then added to the modified catechin in sequence, and stirring was continued until uniformly dispersed to obtain a composite stabilizer.

[0042] After soaking the blueberry fruits in clean water, they are sprayed and rinsed to remove impurities attached to the surface of the blueberry fruits. After cleaning, the blueberry fruits are framed and placed in a freezer at -20°C for 2 hours. The frozen blueberries are placed in a low-temperature grinder, and a composite stabilizer, honey, L-cysteine, and citric acid buffer are added in sequence. The inert gas nitrogen is filled in, and the parameter temperature is set to -10°C, the grinding speed is 10000 rpm / min, and the grinding time is 30 seconds. The grinder is turned on and grinding is performed. The slurry obtained by grinding is filtered to remove pomace and solid impurities to obtain blueberry puree.

[0043] Comparative Example 1: The method of Example 3 was adopted, and the addition amount of the composite stabilizer was 0.01 parts by weight.

[0044] Comparative Example 2: The method of Example 3 was used to prepare a composite stabilizer containing phytic acid and sodium pyrophosphate, and the modified catechin was removed.

[0045] Comparative Example 3: Using the method of Example 3, modified catechin was prepared from catechin and rhamnose in a mass ratio of 1:1.

[0046] The present invention prepares a blueberry puree based on cryogenic grinding and oxidation isolation. In the application of the blueberry puree preparation technology field, the blueberry puree has good active component stability. Specific tests are shown in the following table:

[0047] The protein centrifugal sedimentation rate is a method of precipitating proteins in a sample through high-speed centrifugation. The ratio of the amount of precipitate to the total initial liquid volume is then used to assess the protein precipitation. The degree of protein precipitation can reflect the stability of the protein under specific treatment conditions. The test steps are as follows: Accurately weigh 10mL of blueberry puree sample and centrifuge it in a low-temperature centrifuge at 15,000 rpm / min for 10 minutes. After centrifugation, the volume of the precipitate is measured as a percentage of the total volume.

[0048] The obtained data are shown in Table 1

[0049] Table 1 Performance data of blueberry puree of Examples 1-4 and Comparative Examples 1-3

[0050]

[0051] Comparison of Examples 1-4 and Comparative Examples 1-3 shows that, in a blueberry puree prepared based on cryogenic grinding, oxidation and isolation, the composite stabilizer has a significant effect on the active components in the puree.

[0052] As can be seen from Examples 1-3, as the proportions of the components in the composite stabilizer continue to change, the stability of the active components in a blueberry puree prepared based on cryogenic grinding and oxidative isolation improves. This is because phytic acid, which has antioxidant properties, can help prevent oxidative degradation of the active components and reduce browning. Sodium pyrophosphate, a chelating agent, can chelate metal ions, thereby reducing the catalytic oxidation effect of metal ions on certain components. The modified catechin increases the stability of the catechin through a glycosylation reaction, enhancing its protective ability for other active components in the blueberry puree. The different components produce a synergistic effect, resulting in improved stability of the active components in the blueberry puree.

[0053] According to Examples 3 and 4, as other components in the blueberry puree continue to change, the stability of the active components in a blueberry puree prepared based on cryogenic grinding and oxidative isolation shows almost no significant change. This indicates that the composite stabilizer is a key factor in ensuring the stability of the active components in the blueberry puree, and that changes in other components within a certain range do not significantly affect the active components in the blueberry puree.

[0054] According to the above test experiments, Example 3 is adopted as the optimal example and compared with Comparative Examples 1-3 respectively.

[0055] By comparing Example 3 and Comparative Example 1, it can be seen that when the content of the composite stabilizer is too low, the stability of the active components in a blueberry puree prepared based on low-temperature grinding and oxidation isolation is worse. This is because the lower the content of the composite stabilizer, the weaker its antioxidant properties and protective effects on other active components, which reduces the inhibitory effect on polyphenol oxidase (PPO), making the active components in the blueberry more susceptible to oxidation reactions, and the blueberry puree is more susceptible to oxidative damage. At the same time, it is unable to effectively chelate metal ions in the solution. The metal ions participate in the catalytic reaction and accelerate the occurrence of the oxidation reaction, thereby reducing the overall protection ability of the active components, and the stability of the active components in the blueberry puree is poor.

[0056] By comparing Example 3 and Comparative Example 2, it can be seen that when the composite stabilizer contains phytate and sodium pyrophosphate and the modified catechin is removed, the stability of the active component in the blueberry puree prepared based on low-temperature grinding and oxidative isolation is worse. This is because the modified catechin improves the stability of the catechin through glycosylation, thereby improving its ability to protect the active components of the blueberry. Therefore, the modified catechin has strong antioxidant properties and can more effectively inhibit oxidation reactions and protect the active components from oxidative damage compared to phytate and sodium pyrophosphate. After removing the modified catechin, the antioxidant capacity of the blueberry puree decreases. At the same time, the synergistic effect between phytate, sodium pyrophosphate and modified catechin is weakened due to the lack of modified catechin, resulting in a decrease in the stability of the active component.

[0057] By comparing Example 3 with Comparative Example 3, it can be seen that the modified catechin is prepared from catechin and rhamnose in a mass ratio of 1:1. The stability of the active component in the blueberry puree prepared based on low-temperature grinding and oxidative isolation is worse. This is because glycosylation increases the hydrophilicity of the catechin molecules, making them more soluble in water, which means that catechin can play a better role in the blueberry puree. At the same time, the chemical structure of catechin becomes more complex, which improves the stability of catechin and can maintain its antioxidant activity for a longer time, thereby enhancing its antioxidant effect. When the ratio of catechin to rhamnose is 1:1, since the hydroxyl groups on the catechin molecules are the main sites for glycosylation, the number and position of these hydroxyl groups will affect the position and degree of glycosylation. Therefore, the degree of glycosylation of the modified catechin is insufficient, thereby affecting the overall stability of the blueberry puree.

[0058] The basic principles, main features, and advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention claimed.

Claims

1. A blueberry puree prepared by cryogenic grinding, oxidation and isolation, characterized by: The invention comprises the following components in parts by weight: 90-100 parts by weight of blueberries, 0.1-0.5 parts by weight of a composite stabilizer, 1-5 parts by weight of honey, 0.03-0.05 parts by weight of L-cysteine, and 0.3-0.7 parts by weight of a citric acid buffer solution; The composite stabilizer is obtained by mixing phytic acid, sodium pyrophosphate and modified catechin in a ratio of 1:0.2-0.6:1-3; The modified catechin is prepared by a glycosylation reaction between catechin and rhamnose in the presence of a rhamnosyltransferase catalyst, wherein the mass ratio of catechin to rhamnose is 1:4-8; The specific preparation method of the composite stabilizer is as follows: Catechin and rhamnose are dissolved in a citric acid buffer solution, and then rhamnosyltransferase is added. The mixed solution is placed in a constant temperature water bath for reaction. After the reaction is completed, the enzyme activity is terminated by heating to 80-100°C. The enzyme and other insoluble substances are then removed by a centrifuge to obtain a modified catechin. Subsequently, phytic acid and sodium pyrophosphate are added to the modified catechin in sequence, and stirring is continued until uniformly dispersed to obtain a composite stabilizer.

2. The blueberry puree prepared by cryogenic grinding and oxidation isolation according to claim 1, characterized in that: The pH value of the citric acid buffer is in the range of 5-6.

3. The blueberry puree prepared by cryogenic grinding and oxidation isolation according to claim 1, characterized in that: The water bath temperature for the glycosylation reaction between catechin and rhamnose in the presence of rhamnosyltransferase catalyst is 30-40° C., and the reaction time is 1-2 hours.

4. The blueberry puree prepared by cryogenic grinding and oxidation isolation according to claim 1, characterized in that: The concentration of the rhamnosyltransferase in the mixed solution of catechin and rhamnose is 1-5 U / mL.

5. The blueberry puree prepared by cryogenic grinding and oxidation isolation according to claim 1, characterized in that: The centrifuge parameters are set to 3000-4000 rpm / min, and the centrifugation time is 5-10 min.

6. The blueberry puree prepared by cryogenic grinding and oxidation isolation according to claim 1, characterized in that: The specific preparation method of the blueberry puree is as follows: After soaking the blueberry fruits in clean water, they are sprayed and rinsed to remove impurities attached to the surface of the blueberry fruits. The cleaned blueberry fruits are framed and frozen in a freezer. The frozen blueberries are placed in a low-temperature grinder, and a composite stabilizer, honey, L-cysteine, and citric acid buffer are added in sequence. The inert gas nitrogen is filled in, the parameters are set, the grinder is turned on, and grinding is performed. The slurry obtained by grinding is filtered to remove pomace and solid impurities to obtain blueberry puree.

7. The blueberry puree prepared by cryogenic grinding and oxidation isolation according to claim 6, characterized in that: The blueberries are frozen in the freezer at a temperature of -20°C to -15°C for 1-3 hours.

8. The blueberry puree prepared by cryogenic grinding and oxidation isolation according to claim 6, characterized in that: The low-temperature grinding machine is set with a temperature of -10-0°C, a grinding speed of 10,000-15,000 rpm / min, and a grinding time of 30-60 s.

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