Blueberry compound juice with high anthocyanin content and preparation method thereof

Abstract

The invention relates to the technical field of processing of composite drinks, in particular to blueberry composite juice with high anthocyanin content and a preparation method of the blueberry composite juice. The preparation method of the blueberry compound fruit juice with high anthocyanin content comprises the following steps: under a dark condition, mixing blueberries and other high-anthocyanin fruit raw materials, and carrying out cold pressing treatment to obtain a fruit juice raw juice A and a fruit fiber mixture; soaking the fruit fiber mixture in acidic clear juice at a constant temperature, filtering to obtain original juice B, mixing the original juice A and the original juice B, concentrating, adding a component protection composition, stirring, homogenizing, and sterilizing to obtain the fruit fiber beverage. The blueberry compound fruit juice with high anthocyanin content has the characteristic of high anthocyanin content and high stability.

Description

Technical Field

[0001] The present application relates to the technical field of processing of compound beverages, and more specifically, to a blueberry compound juice with a high anthocyanin content and a preparation method thereof. Background Art

[0002] Anthocyanidins, also known as flower pigments, are a class of blue-red water-soluble flavonoid compounds widely found in plants and are a natural pigment. Anthocyanidins are the most effective antioxidants discovered by humans today, which can delay aging and make the skin smooth and delicate; they are also the most powerful and effective free radical scavengers, which can protect the human body from free radical damage, protect the eyes, regulate lipid and sugar metabolism, improve the circulatory system, eliminate fatigue, and enhance blood vessel elasticity, which helps prevent cardiovascular disease.

[0003] Studies have shown that a reasonable daily dietary intake of anthocyanins is associated with a lower probability of cancer, cardiovascular and cerebrovascular diseases, and other diseases. Adults should consume 100-200 mg of anthocyanins per day. For children, the daily intake of anthocyanins should be half of that of adults. It is still difficult to reach this standard through daily dietary intake. As the market demands, people often use blueberries as one of the raw materials to prepare compound drinks with high anthocyanin content for drinking, to supplement the anthocyanins needed by the human body.

[0004] With respect to the above-mentioned related technologies, the inventors found that the anthocyanin content in the currently commercially available blueberry-containing compound drinks is mostly below 70 mg / 100 mL, and even the anthocyanin content in some drinks is only about 10 mg / 100 mL. This is because the preparation process of the existing blueberry compound drinks is mostly complicated, which often causes a large amount of anthocyanin loss or structural destruction, resulting in a significant reduction in the anthocyanin content in the prepared compound drinks and poor stability, which greatly reduces the nutritional value of the compound drinks. Summary of the invention

[0005] In order to increase the anthocyanin content and stability in a blueberry compound juice, the present application provides a blueberry compound juice with a high anthocyanin content and a preparation method thereof.

[0006] In a first aspect, the present application provides a method for preparing a blueberry composite juice with a high anthocyanin content, using the following technical scheme: In a light-proof condition, blueberries and other high-anthocyanin fruit raw materials are mixed in a mass ratio of (7-9):1 and cold-pressed to obtain a juice A and a fruit fiber mixture; The fruit fiber mixture is soaked in an acidic clear juice at 25-30° C. for 1-1.5 hours at a constant temperature, filtered to obtain a juice B, and the juice A and the juice B are mixed to obtain a juice; The juice raw juices are mixed and concentrated to obtain juice concentrate; The component protection composition is added to the fruit juice concentrate, and the mixture is stirred, homogenized and sterilized to obtain the fruit juice concentrate.

[0007] By adopting the above technical solution, anthocyanins in fruits can be retained and utilized to the maximum extent. Anthocyanins in blueberries and other high-anthocyanin fruit raw materials are mainly present in the peel and pulp, among which the anthocyanin content in the peel is much higher than that in the pulp. By squeezing the juice from the fruit and peel in a light-proof cold pressing method, anthocyanins are not easily affected by light and heat, which may lead to structural damage and loss, and anthocyanins in the fruit and peel can be retained to the maximum extent and the activity of anthocyanins can be maintained.

[0008] The fruit fiber mixture obtained after filtering is mostly the peels of blueberries and other high-anthocyanin fruit raw materials, which are still rich in anthocyanins. The water-solubility of anthocyanins is used to further dissolve and utilize the anthocyanins in the fruit fiber mixture by soaking it, so as to obtain anthocyanin-rich juice B and reduce the loss and waste of anthocyanins.

[0009] After the fruit and the fruit fiber mixture are processed and reused separately, the juice original juices A and B are mixed to obtain the juice original juice, which retains and utilizes the anthocyanins in different fruits to the maximum extent, significantly reduces the loss and waste of anthocyanins, and increases the anthocyanin content in the blueberry compound juice.

[0010] Optionally, the other high anthocyanin fruit raw materials are selected from one or more of grapes, mulberries, wolfberries, blackberries, cranberries, strawberries, pomegranates, cherries, red oranges, hawthorns, and raspberries.

[0011] By adopting the above technical scheme, grapes, mulberries, wolfberries, blackberries, cranberries, strawberries, pomegranates, cherries, red oranges, hawthorns, and raspberries are all fruits rich in anthocyanins and have rich nutritional value. The use of a variety of fruit raw materials mixed with blueberries can develop a variety of juice products with different flavors and aromas, which helps to meet the diversified market requirements.

[0012] Optionally, the volume ratio of the acidic clear juice to the fruit juice A is 1:(1-1.5), and the acidic clear juice includes lemon juice with a concentration of 0.2-3%.

[0013] By adopting the above technical solution, lemon juice can adjust the pH of acidic clear juice to make the clear juice acidic. Under acidic conditions, the fruit cell walls and cell membranes become more relaxed, which is conducive to the diffusion and dissolution of anthocyanin molecules in the fruit fiber mixture in the acidic clear juice. Acidic conditions are conducive to the anthocyanin to show higher stability, and can prevent anthocyanin from being degraded into chalcones, alcohol-type pseudoalkaloids and the like and becoming inactivated.

[0014] The addition of lemon juice can promote the release efficiency of anthocyanins and further improve the content and stability of anthocyanins in the original juice B extracted from the fruit fiber mixture.

[0015] Optionally, the concentration of the ingredient protection composition is 0.02-0.08%, and the ingredient protection composition comprises tea concentrate and a protein component in a mass ratio of (1.5-1.8):1, and the protein component is selected from whey protein or polypeptide.

[0016] By adopting the above technical scheme, the tea concentrate is rich in tea polyphenols, and tea polyphenols can form non-covalent complexes with anthocyanins through the π-π stacking force, hydrogen bond and van der Waals force between aromatic rings, blocking the nucleophilic attack of water molecules on anthocyanin molecules, thereby preventing anthocyanins from forming chalcone structures and degrading and inactivating, and can significantly improve the stability of anthocyanins in blueberry compound fruit and vegetable juice; whey protein belongs to food protein, and can form a complex with anthocyanins through hydrophobic interaction, so that anthocyanins and proteins form a strong binding effect, which can effectively reduce the sensitivity of anthocyanins to adverse factors and improve the stability of anthocyanins in compound blueberry fruit and vegetable juice; the addition of polypeptides can form a protective layer on the one hand, wrapping anthocyanin molecules, reducing their direct contact with the external environment (such as oxygen, light, temperature changes, etc.), thereby reducing the degradation rate of anthocyanins; on the other hand, polypeptides can improve the interaction between anthocyanin molecules through their own molecular structure, reduce aggregation or precipitation, and improve their dispersibility in solution.

[0017] Optionally, the method for mixing and concentrating the original juice A and the original juice B is negative pressure vacuum concentration.

[0018] By using the above technical solution, the present application performs negative pressure vacuum concentration on the mixed fruit juice, which can effectively reduce the loss rate of anthocyanins caused by high temperature compared to traditional thermal evaporation.

[0019] In a second aspect, the present application provides a blueberry compound fruit and vegetable juice with a high anthocyanin content, characterized in that it is made by a preparation method of a blueberry compound fruit and vegetable juice with a high anthocyanin content.

[0020] By adopting the above technical scheme, the method for preparing a blueberry compound juice with a high anthocyanin content of the present application can prepare a blueberry compound juice with a high anthocyanin content and stability and a better taste.

[0021] In a third aspect, the present application provides a method for preparing a blueberry composite fruit and vegetable juice with a high anthocyanin content, using the following technical solution: In a light-proof condition, blueberries and other high-anthocyanin fruit raw materials are mixed in a mass ratio of (7-9):1 and cold-pressed to obtain a juice A and a fruit fiber mixture; The fruit fiber mixture is soaked in an acidic clear juice at 25-30° C. for 6-8 hours at a constant temperature, filtered to obtain a juice B, and the juice A and the juice B are mixed to obtain a juice; The juice raw juices are mixed and concentrated to obtain juice concentrate; The raw materials of high anthocyanin vegetables or grains in a mass ratio of (3-11):(15-20) are mixed with water, crushed, steamed and cooked to obtain vegetable juice; The fruit juice concentrate and the vegetable original juice are mixed in a volume ratio of (6-8):1, and then the ingredient protection composition is added, stirred, homogenized, and then sterilized to obtain the product.

[0022] By adopting the above technical scheme, most of the high-anthocyanin vegetables or grain raw materials have thicker cell walls and lower water content, which makes their anthocyanins difficult to release. Heat treatment at an appropriate temperature helps to decompose the cell walls and other cell structures, so that the anthocyanins in the high-anthocyanin vegetables or grain raw materials are better released, thereby preparing a composite fruit and vegetable juice with a high anthocyanin content.

[0023] By preparing fruit and vegetable juice from blueberries, other high-anthocyanin fruit raw materials and high-anthocyanin vegetables or grain raw materials through different processing methods, the anthocyanins in different fruits and vegetables can be retained to the maximum extent according to the different characteristics of fruits and vegetables, thereby improving the anthocyanin content and stability of the subsequently prepared blueberry composite fruit and vegetable juice.

[0024] Optionally, the high anthocyanin vegetable or grain raw material is selected from one or more of black corn kernels, purple sweet potatoes, purple cabbage, purple potatoes, purple yams, perilla, black rice, red rice, and red beets.

[0025] By adopting the above technical scheme, black corn, purple sweet potato, purple cabbage, purple potato, purple yam, perilla, black rice, red rice and red beet are all rich in anthocyanins. The use of a variety of raw materials can provide richer anthocyanin types and a wider range of health benefits. The use of a variety of different vegetable or grain raw materials can develop a series of products with different flavors and styles to meet the preferences of different consumers.

[0026] Optionally, the vegetable juice is pretreated as follows before being mixed with the fruit juice concentrate: Add saccharifying enzyme in an amount of 1-2% of the total mass of the high-anthocyanin vegetable or grain raw material to the vegetable juice, and perform macromolecular sugar degradation treatment at 40-45° C. for 2-2.5 hours.

[0027] By adopting the above technical scheme, under the action of saccharifying enzyme, the vegetable juice is subjected to macromolecular sugar degradation treatment, which can, on the one hand, enhance the sweetness of the vegetable juice and improve the taste of the final blueberry compound fruit and vegetable juice; on the other hand, the macromolecular sugar degradation treatment converts the starch in vegetables with high starch content into glucose and sucrose, and the sugar molecules can undergo glycosylation with anthocyanin molecules to generate glycosidic bonds. The hydrogen bonds in the glycosylated anthocyanin form effective steric hindrance, making the structure of anthocyanin more complex and stable, and can effectively reduce the degradation rate of anthocyanin without affecting the subsequent absorption by the human body, thereby significantly improving the stability of anthocyanin.

[0028] In a fourth aspect, the present application provides a blueberry composite fruit and vegetable juice with a high anthocyanin content, characterized in that it is prepared by a method for preparing a blueberry composite fruit and vegetable juice with a high anthocyanin content.

[0029] By adopting the above technical scheme, the method for preparing a blueberry composite fruit and vegetable juice with a high anthocyanin content of the present application can prepare a blueberry composite fruit and vegetable juice with a high anthocyanin content and stability and a better taste.

[0030] In summary, this application has the following beneficial effects: 1. The present application selects blueberries, other high-anthocyanin fruit raw materials, high-anthocyanin vegetables or grain raw materials, and adopts different processing methods to prepare fruit juice / fruit and vegetable juice according to the different characteristics of fruits, vegetables and grains, which effectively reduces the degradation of anthocyanins, retains the anthocyanins in different fruits and vegetables to the maximum extent, and effectively improves the anthocyanin content in the final prepared blueberry composite fruit juice / fruit and vegetable juice; different processing methods make the anthocyanins in the final prepared blueberry composite fruit juice / fruit and vegetable juice have different structures and dispersion characteristics, which can effectively improve the stability of the composite blueberry fruit juice / fruit and vegetable juice.

[0031] 2. The fruit fiber mixture was soaked in acidic juice to effectively extract anthocyanins from the fruit fiber mixture. The acidic environment helped prevent the molecular structure of anthocyanins from being destroyed, significantly increasing the anthocyanin content and stability in blueberry compound juice / fruit and vegetable juice.

[0032] 3. The blueberry compound juice / fruit and vegetable juice of the present application is added with tea concentrate and protein components, which can generate stronger binding force with anthocyanin molecules to form a more stable structure, effectively slow down the degradation rate of anthocyanins, and further improve the stability of anthocyanins in the compound blueberry juice / fruit and vegetable juice.

[0033] 4. The preparation methods of the present application are all carried out under light-proof conditions and at an appropriate temperature, which reduces the loss and waste of anthocyanins or the destruction of their structure caused by factors such as light and high temperature that have adverse effects on anthocyanins during the preparation of fruit juice / fruit and vegetable juice, and helps to increase the anthocyanin content in the preparation of blueberry compound fruit juice / fruit and vegetable juice. DETAILED DESCRIPTION

[0034] The present application is further described in detail below in conjunction with embodiments, preparation examples and comparative examples.

[0035] Material Source Unless otherwise specified, the raw materials used in the preparation examples and examples in this application are all commercially available products, specifically: Glucoamylase was selected from Wuhan Binghe Food Ingredients Co., Ltd., 027; The tea concentrate is green tea concentrate, containing 50% tea polyphenols; The whey protein is food grade whey protein; The polypeptide was selected from the food-grade polypeptide of Jinan Shenghe Chemical Co., Ltd., model number XH8190JJGFFV.

[0036] Example of preparation of fruit juice Preparation Example 1.1 The method for preparing the original fruit juice comprises the following steps: S1. In a dark environment, blueberries and other high-anthocyanin fruit raw materials were mixed in a mass ratio of 8:1 (referred to as raw material mass ratio 1 in Table 1), washed and put into a cold pressing juice extraction device for cold pressing to obtain juice A and a fruit fiber mixture. Other high-anthocyanin fruit raw materials included grapes, mulberries and raspberries in a mass ratio of 1:1:1; S2, select fresh lemons, squeeze and filter the juice, add the filtered lemon juice into a water container to prepare acidic clear juice, wherein the lemon juice concentration in the acidic clear juice is 3%; S3. Take the acidic clear juice prepared in step S2, the volume ratio of the acidic clear juice to the fruit juice A (referred to as volume ratio in Table 1) is 1:1.5, soak the fruit fiber mixture in the acidic clear juice at 25° C. for 1.5 h (referred to as soaking time in Table 1), filter to obtain fruit juice B, and mix the pretreated fruit juice A and the fruit juice B to obtain fruit juice.

[0037] Table 1 Raw material ratio and production and processing parameters of juice production Preparation Example 1.1 Preparation Example 1.2 Preparation Example 1.3 Raw material quality ratio 1 8:1 7:1 9:1 Acidic juice temperature / ℃ 25 27 30 Soaking time / h 1.5 1.5 1 Volume ratio 1:1.5 1:1.2 1:1 Lemon juice concentration / % 3 0.2 1.5 Preparation Example 1.2 The method for preparing fruit juice is different from that of Preparation Example 1.1 in that the ratio of each production raw material and the production and processing parameters in the preparation process are shown in Table 1, and other high anthocyanin fruit raw materials include mulberry, pomegranate, cherry, red orange, and hawthorn in a mass ratio of 1:1:1:1:1. The other steps are the same as those in Preparation Example 1.1.

[0038] Preparation Example 1.3 The method for preparing the original fruit juice is different from that of Preparation Example 1.1 in that the ratio of each production raw material and the production and processing parameters in the preparation process are shown in Table 1, and other high anthocyanin fruit raw materials include blackberry, cranberry, and grape in a mass ratio of 1:1:1. The other steps are the same as those in Preparation Example 1.1.

[0039] Preparation Example 1.4 The method for preparing the original fruit juice is different from that in Preparation Example 1.1 in that there is no lemon juice in the acidic clear juice, and the acidic clear juice is clear water. The other steps are the same as those in Preparation Example 1.1.

[0040] Preparation Example 1.5 The method for preparing the original fruit juice comprises the following steps: S1. In a dark environment, blueberries and other high-anthocyanin fruit raw materials are mixed in a mass ratio of 8:1, washed and put into a cold pressing juice extraction device for cold pressing to obtain pretreated juice. Other high-anthocyanin fruit raw materials include grapes and mulberries in a mass ratio of 1:1. S2. Add clean water to the pretreated fruit juice to dilute it to obtain original fruit juice, and the volume ratio of the added clean water to the pretreated fruit juice is 1:1.5.

[0041] Example of vegetable juice preparation Preparation Example 2.1 The method for preparing vegetable juice comprises the following steps: S1. Mixing high-anthocyanin vegetable or grain raw materials and water in a mass ratio of 3:15, crushing, steaming and cooking to obtain a viscous liquid. The high-anthocyanin vegetable or grain raw materials include black corn kernels, black rice and purple sweet potatoes in a mass ratio of 2:1:1; S2. Add saccharifying enzyme in an amount of 1% of the total mass of the high-anthocyanin vegetable or grain raw material to the viscous liquid, perform macromolecular sugar degradation treatment at 45° C. for 2.5 hours, and obtain vegetable juice with a sweetness value of 16.

[0042] Preparation Example 2.2 The method for preparing vegetable juice comprises the following steps: S1. Mixing high-anthocyanin vegetable or grain raw materials and water in a mass ratio of 8:17, crushing, steaming and cooking to obtain a viscous liquid, wherein the high-anthocyanin vegetable or grain raw materials include purple cabbage, perilla and purple yam in a mass ratio of 2:1:1; S2. Add saccharifying enzyme in an amount of 1% of the total mass of the high-anthocyanin vegetable or grain raw material to the viscous liquid, perform macromolecular sugar degradation treatment at 45° C. for 2.5 hours, and obtain vegetable juice with a sweetness value of 18.

[0043] Preparation Example 2.3 The method for preparing vegetable juice comprises the following steps: S1. Mixing high-anthocyanin vegetable or cereal raw materials and water in a mass ratio of 11:20, crushing, steaming and cooking to obtain a viscous liquid. The high-anthocyanin vegetable or cereal raw materials include purple potatoes, purple rice, red rice and red beets in a mass ratio of 2:1:1:1; S2. Add saccharifying enzyme in an amount of 1% of the total mass of the high-anthocyanin vegetable or grain raw material to the viscous liquid, perform macromolecular sugar degradation treatment at 45° C. for 2.5 hours, and obtain vegetable juice with a sweetness value of 17.

[0044] Preparation Example 2.4 The method for preparing vegetable juice comprises the following steps: The high-anthocyanin vegetable or grain raw materials and water in a mass ratio of 3:15 are mixed, crushed, steamed and cooked to obtain vegetable juice, wherein the high-anthocyanin vegetable or grain raw materials include black corn kernels and purple sweet potatoes in a mass ratio of 2:1; Example

[0045] An embodiment of a blueberry compound juice with high anthocyanin content Example 1.1 A blueberry compound juice with a high anthocyanin content, the preparation method of which comprises the following steps: S1. Add the juice prepared in Preparation Example 1.1 into a vacuum decompression concentrator for negative pressure vacuum concentration, and concentrate the juice to 2 / 3 of the original volume to obtain juice concentrate; S2. Adding an ingredient protection composition to the fruit juice concentrate, wherein the mass concentration of the ingredient protection composition is 0.06%, and the ingredient protection composition comprises tea concentrate and whey protein in a mass ratio of 1.5:1, stirring and homogenizing, and then sterilizing.

[0046] Example 1.2 A blueberry compound juice with a high anthocyanin content, the preparation method of which comprises the following steps: S1. Add the juice prepared in Preparation Example 1.2 into a vacuum concentrator for negative pressure vacuum concentration, and concentrate the juice to 2 / 3 of the original volume to obtain juice concentrate; S2. Adding an ingredient protection composition to the fruit juice concentrate, wherein the mass concentration of the ingredient protection composition is 0.02%, and the ingredient protection composition comprises tea concentrate and polypeptide in a mass ratio of 1.6:1, stirring and homogenizing, and then sterilizing.

[0047] Example 1.3 A blueberry compound juice with a high anthocyanin content, the preparation method of which comprises the following steps: S1. Add the juice prepared in Preparation Example 1.3 into a vacuum concentrator for negative pressure vacuum concentration, and concentrate the juice to 2 / 3 of the original volume to obtain juice concentrate; S2. Adding an ingredient protection composition to the fruit juice concentrate, wherein the mass concentration of the ingredient protection composition is 0.08%, and the ingredient protection composition comprises tea concentrate and polypeptide in a mass ratio of 1.8:1, stirring and homogenizing, and then sterilizing.

[0048] Example 1.4 A blueberry compound juice with a high anthocyanin content, which is different from Example 1.1 in that the original juice is prepared by Preparation Example 1.4, and the other steps are the same as Example 1.1.

[0049] Example 1.5 A blueberry compound juice with a high anthocyanin content, which is different from Example 1.1 in that the ingredient protection composition added in step S2 does not contain tea concentrate, and the other steps are the same as Example 1.1.

[0050] Example 1.6 A blueberry compound juice with a high anthocyanin content, which is different from Example 1.1 in that the ingredient protection composition added in step S2 does not contain whey protein, and the other steps are the same as Example 1.1.

[0051] An embodiment of a blueberry composite fruit and vegetable juice with high anthocyanin content Example 2.1 A blueberry composite fruit and vegetable juice with a high anthocyanin content, the preparation method of which comprises the following steps: S1. Add the juice prepared in Preparation Example 1.1 into a vacuum concentrator for negative pressure vacuum concentration, and concentrate the juice to 2 / 3 of its original volume to obtain juice concentrate; S2. Mix the fruit and vegetable concentrate with the vegetable juice prepared in Preparation Example 2.1 in a volume ratio of 6:1, and then add the ingredient protection composition. The mass concentration of the ingredient protection composition is 0.06%. The ingredient protection composition includes tea concentrate and whey protein in a mass ratio of 1.5:1. Stir and homogenize, and then sterilize.

[0052] Example 2.2 A blueberry composite fruit and vegetable juice with a high anthocyanin content, the preparation method of which comprises the following steps: S1. Add the juice prepared in Preparation Example 1.2 into a vacuum concentrator for negative pressure vacuum concentration, and concentrate the juice to 2 / 3 of its original volume to obtain juice concentrate; S2. Mix the fruit and vegetable concentrate with the vegetable juice prepared in Preparation Example 2.2 in a volume ratio of 7:1, and then add the ingredient protection composition. The mass concentration of the ingredient protection composition is 0.06%. The ingredient protection composition includes tea concentrate and whey protein in a mass ratio of 1.5:1. Stir and homogenize, and then sterilize.

[0053] Example 2.3 A blueberry composite fruit and vegetable juice with a high anthocyanin content, the preparation method of which comprises the following steps: S1. Add the juice prepared in Preparation Example 1.3 into a vacuum decompression concentrator for negative pressure vacuum concentration, and concentrate the juice to 2 / 3 of the original volume to obtain juice concentrate; S2. Mix the fruit and vegetable concentrate with the vegetable juice prepared in Preparation Example 2.3 in a volume ratio of 8:1, and then add the ingredient protection composition. The mass concentration of the ingredient protection composition is 0.06%. The ingredient protection composition includes tea concentrate and whey protein in a mass ratio of 1.5:1. Stir and homogenize, then sterilize.

[0054] Example 2.4 A blueberry composite fruit and vegetable juice with a high anthocyanin content, which is different from Example 2.1 in that the vegetable juice is prepared by Preparation Example 2.4, and the other steps are the same as Example 2.1.

[0055] Example 2.5 A blueberry composite fruit and vegetable juice with a high anthocyanin content, which is different from Example 2.1 in that the ingredient protection composition added in step S2 does not contain tea concentrate, and the other steps are the same as Example 2.1.

[0056] Example 2.6 A blueberry composite fruit and vegetable juice with a high anthocyanin content, which differs from Example 2.1 in that the ingredient protection composition added in step S2 does not contain whey protein, and the other steps are the same as Example 2.1.

[0057] Comparative Example Comparative Example 1 A blueberry compound juice with a high anthocyanin content, which is different from Example 1.1 in that the original juice is prepared by Preparation Example 1.5, and the other steps are the same as Example 1.1.

[0058] Comparative Example 2 A blueberry compound juice with a high anthocyanin content, which differs from Example 1.1 in that no ingredient protection composition is added, and the other steps are the same as Example 1.1.

[0059] Comparative Example 3 A blueberry composite fruit and vegetable juice with a high anthocyanin content, which differs from Example 2.1 in that no ingredient protection composition is added, and the other steps are the same as Example 2.1.

[0060] Performance testing A performance test was performed on a blueberry composite juice with a high anthocyanin content in Examples 1.1-1.6 and Comparative Examples 1-2. Each group of tests was tested 3 times, and the average value was recorded in Table 2. A performance test was performed on a blueberry composite fruit and vegetable juice with a high anthocyanin content in Examples 2.1-2.6 and Comparative Example 3. Each group of tests was tested 3 times, and the average value was recorded in Table 2.

[0061] The anthocyanin content was determined according to the determination method specified in NYT2640-2014 "Determination of anthocyanins in plant-derived foods—High Performance Liquid Chromatography"; the thermal degradation half-life of each group of tests under heating at 80°C and the light half-life of anthocyanins under fluorescent light were determined respectively.

[0062] Free radical scavenging experiment: Dissolve the sample in ethanol to prepare a solution, add 2 mL of the sample solution and 2 mL of a 100 μmol / L DPPH solution into the same stoppered test tube, shake well, let stand at room temperature for 30 min, and measure the sample absorbance at a wavelength of 517 nm; the samples are Examples 1.1-1.6, Examples 2.1-2.6 and Comparative Examples 1-3.

[0063] Inhibition rate: K% = [1-(Ai-Aj) / Ac] × 100% Ai: absorbance of 2mL DPPH solution + 2mL test solution; Aj: absorbance of 2mL test solution + 2mL solvent; Ac: absorbance of 2mL DPPH solution + 2mL solvent; Table 2 It can be seen from the performance test data in Table 2 that the anthocyanin content per 100mL of a blueberry compound juice with a high anthocyanin content of the present application is 179.4-183.6mg, and the anthocyanin content per 100mL of a blueberry compound fruit and vegetable juice with a high anthocyanin content of the present application is 187.7-190.1mg, which is much higher than the commercially available compound fruit juice / fruit and vegetable beverage containing blueberries; the thermal decomposition half-life and light half-life of anthocyanins in a blueberry compound fruit juice / fruit and vegetable juice with a high anthocyanin content of the present application are significantly prolonged, which indicates that the sensitivity of anthocyanins in a blueberry compound fruit juice / fruit and vegetable juice with a high anthocyanin content of the present application to external adverse factors is significantly reduced, and the stability of anthocyanins is significantly improved; a blueberry compound fruit juice / fruit and vegetable juice with a high anthocyanin content of the present application has a good ability to remove DPPH, which indicates that a blueberry compound fruit juice / fruit and vegetable juice with a high anthocyanin content of the present application has the characteristics of high antioxidant and strong activity.

[0064] It can be seen from the performance test data of Examples 1.1-1.4 and Comparative Example 1 that the fruit fiber mixture still contains a large amount of anthocyanins. Soaking the fruit fiber mixture in acidic juice prepared with lemon juice can effectively promote the precipitation of anthocyanins in the fruit fiber mixture, significantly increase the anthocyanin content of the blueberry compound juice / fruit and vegetable juice, and the anthocyanins show better light and heat stability in an acidic environment.

[0065] It can be seen from the performance test data of Examples 2.1-2.3 and Example 2.4 that the degradation of macromolecular sugars by saccharifying enzymes helps to enhance the complexity and stability of the anthocyanin structure, thereby improving the stability of anthocyanins in blueberry compound juice / fruit and vegetable juice.

[0066] It can be seen from the performance test data of Examples 1.5-1.6, Examples 2.5-2.6 and Comparative Examples 2-3 that the addition of tea concentrate and protein components (whey protein or polypeptides) can form a more stable structure with anthocyanins, thereby significantly improving the light and heat stability of high-content anthocyanins in blueberry compound juice / fruit and vegetable juice. Both tea concentrate and protein components (whey protein or polypeptides) make significant contributions to the stability of anthocyanins, and the synergistic effect produced by the cooperation between the two makes a greater contribution to the improvement of the stability of anthocyanins.

[0067] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a blueberry compound juice with a high anthocyanin content, characterized in that: The following steps are involved: In a light-proof condition, blueberries and other high-anthocyanin fruit raw materials are mixed in a mass ratio of (7-9):1 and cold-pressed to obtain a juice A and a fruit fiber mixture; The fruit fiber mixture is soaked in an acidic clear juice at 25-30° C. for 1-1.5 hours at a constant temperature, filtered to obtain a juice B, and the juice A and the juice B are mixed to obtain a juice; The juice raw juices are mixed and concentrated to obtain juice concentrate; The component protection composition is added to the fruit juice concentrate, and the mixture is stirred, homogenized and sterilized to obtain the fruit juice concentrate.

2. The method for preparing a blueberry composite juice with a high anthocyanin content according to claim 1, characterized in that: The other high-anthocyanin fruit raw materials are selected from one or more of grapes, mulberries, wolfberries, blackberries, cranberries, strawberries, pomegranates, cherries, red oranges, hawthorns, and raspberries.

3. The method for preparing a blueberry composite juice with a high anthocyanin content according to claim 1, characterized in that: The volume ratio of the acidic clear juice to the fruit juice A is 1:(1-1.5), and the acidic clear juice includes lemon juice with a concentration of 0.2-3%.

4. The method for preparing a blueberry composite juice with a high anthocyanin content according to claim 1, characterized in that: The concentration of the ingredient protection composition is 0.02-0.08%, and the ingredient protection composition comprises tea concentrate and a protein component in a mass ratio of (1.5-1.8):1, and the protein component is selected from whey protein or polypeptide.

5. The method for preparing a blueberry composite juice with a high anthocyanin content according to claim 1, characterized in that: The method for mixing and concentrating the original juice A and the original juice B is negative pressure vacuum concentration.

6. A blueberry compound juice with a high anthocyanin content, characterized in that: The blueberry compound juice with high anthocyanin content is prepared by the preparation method of any one of claims 1 to 5.

7. A method for preparing a blueberry composite fruit and vegetable juice with a high anthocyanin content, characterized in that: The following steps are involved: In a light-proof condition, blueberries and other high-anthocyanin fruit raw materials are mixed in a mass ratio of (7-9):1 and cold-pressed to obtain a juice A and a fruit fiber mixture; The fruit fiber mixture is soaked in an acidic clear juice at 25-30° C. for 6-8 hours at a constant temperature, filtered to obtain a juice B, and the juice A and the juice B are mixed to obtain a juice; The juice raw juices are mixed and concentrated to obtain juice concentrate; The raw materials of high anthocyanin vegetables or grains in a mass ratio of (3-11):(15-20) are mixed with water, crushed, steamed and cooked to obtain vegetable juice; The fruit juice concentrate and the vegetable original juice are mixed in a volume ratio of (6-8):1, and then the ingredient protection composition is added, stirred, homogenized, and then sterilized to obtain the product.

8. The method for preparing a blueberry composite fruit and vegetable juice with a high anthocyanin content according to claim 7, characterized in that: The high anthocyanin vegetable or grain raw material is selected from one or more of black corn kernels, purple sweet potatoes, purple cabbages, purple potatoes, purple yams, purple perilla, black rice, red rice, and red beets.

9. The method for preparing a blueberry composite fruit and vegetable juice with a high anthocyanin content according to claim 7, characterized in that: The vegetable juice is pre-treated as follows before being mixed with the fruit juice concentrate: Add saccharifying enzyme in an amount of 1-2% of the total mass of the high-anthocyanin vegetable or grain raw material to the vegetable juice, and perform macromolecular sugar degradation treatment at 40-45° C. for 2-2.5 hours.

10. A blueberry composite fruit and vegetable juice with a high anthocyanin content, characterized in that: The blueberry composite fruit and vegetable juice with high anthocyanin content is prepared by the preparation method of any one of claims 7 to 9.

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