Preparation method of blueberry composite fruit and vegetable juice capable of improving stability of anthocyanin

Abstract

The invention particularly discloses a preparation method of blueberry compound fruit and vegetable juice capable of improving the stability of anthocyanin. Comprising the following steps: (1) cleaning and pulping a fruit and vegetable composition to obtain mixed juice, and adding compound enzyme for enzymolysis to obtain crude fruit and vegetable juice; (2) adjusting the pH value of the crude fruit and vegetable juice obtained in the step (1) to 3.5-3.9, inoculating activated compound bacteria, fermenting to obtain a fermentation product, adding a stable composition, uniformly stirring, and filtering to obtain a mixed solution; (3) heating the mixed solution at 64-65 DEG C for 4-8 minutes, and performing enzyme inactivation and sterilization to obtain compound fruit and vegetable juice; the stable composition comprises one or more of Arabic gum, carrageenan, grape seed oil and fucoidin. The compound fruit and vegetable juice is high in anthocyanin content, the stability of anthocyanin is improved by adding the stable composition, and the anthocyanin is protected against high-temperature damage.

Description

Technical Field

[0001] The present application relates to the technical field of food processing, and more specifically, to a method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability. Background Art

[0002] Anthocyanidins, also known as flower pigments, are a type of water-soluble natural pigments found in plants. They belong to bioflavonoid compounds and are also the main coloring substances in fruit plants. Purple fruits, vegetables, and flowers all contain anthocyanidins. Anthocyanidins have the functional properties of anti-oxidation and free radical scavenging, anti-mutation and anti-tumor, anti-hyperglycemia, prevention of cardiovascular diseases, relief of liver dysfunction, and lowering of blood pressure, and are very popular among people.

[0003] There are many methods for extracting anthocyanins. Enzymatic extraction is usually used, using enzymes such as cellulase and pectinase to soften, swell and collapse the cell walls of fruits and vegetables, thereby promoting the dissolution of anthocyanins. This method is simple to operate, but the enzyme inactivation temperature is usually 75-80°C. Since anthocyanins are heat-sensitive active substances, they will generally be significantly damaged above 70°C, and are easily oxidized and decomposed, thereby losing their activity, which in turn limits the application of anthocyanins. Summary of the invention

[0004] In order to improve the problem that anthocyanins are easily decomposed at high temperatures, the present application provides a method for preparing a blueberry composite fruit and vegetable juice that improves the stability of anthocyanins.

[0005] In a first aspect, the present application provides a method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability, using the following technical solution: A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability comprises the following steps: (1) washing and pulping the fruit and vegetable composition to obtain a mixed juice, adding a composite enzyme for enzymolysis to obtain a crude fruit and vegetable juice; (2) adjusting the pH value of the crude fruit and vegetable juice of step (1) to 3.5-3.9, inoculating the activated complex bacillus, and then fermenting to obtain a fermentation product, adding the stabilizing composition, stirring evenly, and filtering to obtain a mixed solution; (3) heating the mixed solution at 64-65° C. for 4-8 minutes to inactivate the enzyme and sterilize the mixture to obtain a composite fruit and vegetable juice; The fruit and vegetable composition comprises blueberry and other components, wherein the other components are at least two of mulberry, purple cabbage, grape, mulberry, wolfberry, blackberry, cranberry, strawberry, pomegranate, cherry, red orange, hawthorn, raspberry, purple cabbage, black corn, and purple sweet potato; The composite bacteria include one or more of Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus plantarum, Lactobacillus paracasei, and Bifidobacterium animalis; The stabilizing composition comprises one or more of gum arabic, carrageenan, grape seed oil and fucoidan.

[0006] By adopting the above technical scheme, fruits and vegetables contain anthocyanins, which have the effects of anti-oxidation, regulating blood lipids, protecting eyesight, anti-aging, preventing cardiovascular and cerebrovascular diseases, etc., and play an important role in people's health. First, the fruits and vegetables are crushed and then enzymolyzed with a composite enzyme. The composite enzyme removes turbid substances such as suspended matter and colloidal substances in the juice to help preserve the fruits and vegetables. The obtained crude fruit and vegetable juice is fermented to obtain a fermentation product rich in anthocyanins, which is mixed with a stable composition to obtain a mixed solution; in the stable composition, arabic gum, carrageenan or fucoidan are added. These components are all anionic polysaccharides, which can be combined with anthocyanins through electrostatic interactions to form a stable complex. At the same time, the sulfate group in the polysaccharide can be combined with anthocyanins through hydrophobic interactions to improve the stability of anthocyanins. Grape seed oil has an antioxidant effect, can protect the activity of anthocyanins, and is helpful for the storage stability of anthocyanins, thereby improving the stability of anthocyanins.

[0007] Optionally, the complex enzyme consists of pectinase, cellulase and glucose oxidase in a mass ratio of 1:0.3-0.6:0.5-0.8.

[0008] By adopting the above technical scheme, the composite enzyme removes turbid substances such as suspended matter and colloidal substances in the fruit juice, which helps to preserve the fruits and vegetables. Among them, pectinase effectively decomposes pectin substances in fruit and vegetable juice and improves the juice yield of fruit and vegetable juice. Cellulase degrades the macromolecular fibers in the fruit and vegetable juice into cellobiose and glucose molecules with smaller molecular weights. Glucose oxidase effectively removes oxygen and improves the preservation effect, thereby improving the system stability of crude fruit and vegetable juice. Pectinase, cellulase and glucose oxidase are mixed in a certain proportion, and the obtained composite enzyme has a good enzymatic hydrolysis effect, and crude fruit and vegetable juice with good stability is obtained.

[0009] Optionally, in step (2), the fermentation conditions are: constant temperature fermentation at 37-40°C for 4-8 hours.

[0010] By adopting the above technical solution and setting appropriate fermentation conditions, the fermentation of crude fruit and vegetable juice is facilitated, the nutritional value of the crude fruit and vegetable juice is improved, and the shelf life of the crude fruit and vegetable juice is extended.

[0011] Optionally, the stabilizing composition comprises, by weight, 5-10 parts of gum arabic, 3-6 parts of carrageenan, 7-12 parts of grape seed oil and 2-5 parts of fucoidan.

[0012] By adopting the above technical scheme, the amount of each component in the composition is further limited, so that the combination of each component has better stability, gum arabic has better viscosity and stability, carrageenan further enhances the stability of gum arabic, and the combination of gum arabic and carrageenan increases the stability of anthocyanins; fucoidan has good antioxidant, moisturizing and antibacterial effects, and various components cooperate with each other and combine with anthocyanins through electrostatic interactions to form stable complexes. At the same time, the sulfate groups in various components combine with anthocyanins through hydrophobic interactions, which improves the stability of anthocyanins, further protects the activity of anthocyanins, and contributes to the storage stability of anthocyanins.

[0013] Optionally, the mass ratio of gum arabic, grape seed oil and fucoidan is 2-4:3-5:1.

[0014] By adopting the above technical scheme, the mass ratio of gum arabic, grape seed oil and fucoidan is further limited, so that the combination of each component has better stability. The combination of gum arabic, grape seed oil and fucoidan improves the stability of anthocyanins, protects the activity of anthocyanins, and contributes to the storage stability of anthocyanins.

[0015] Optionally, in step (3), the sterilization conditions are: low-temperature plasma sterilization, the sterilization process is: frequency 5-20kHz, electrode spacing 5-20mm, voltage 50-100V, processing time 1-5min, and processing temperature is room temperature.

[0016] By adopting the above technical scheme, low-temperature plasma sterilization can not only effectively protect the stability and biological activity of anthocyanins, but also achieve efficient, safe and environmentally friendly sterilization effects, effectively reduce the oxidation and decomposition of anthocyanins at high temperatures, maintain their natural color and biological activity, improve the quality and nutritional value of compound fruit and vegetable juices, and extend the shelf life of compound fruit and vegetable juices.

[0017] Optionally, the stable composition further comprises microcapsules, and the preparation method of the microcapsules comprises the following steps: uniformly mixing peach gum, modified starch, glacial acetic acid, honey, locust bean gum and water to obtain capsule walls; Mixing citric acid, catechins, vitamin C and sea buckthorn seed oil to obtain capsule core liquid; The capsule wall, capsule core liquid and emulsifier are mixed, homogenized under high pressure and dried to obtain microcapsules.

[0018] By adopting the above technical scheme, peach gum not only contains nutrients such as amino acids and vitamins, which have the effect of beautifying and rejuvenating the skin, but also has anti-inflammatory effect, viscosity and elasticity. The modified starch has good thickening properties and is cross-linked with peach gum to increase the viscosity and consistency of the system, which helps to improve the thickness and uniformity of the subsequent microcapsule wall film and increase the mechanical strength of the microcapsule wall film.

[0019] Glacial acetic acid further adjusts the pH of the system, so that the various components are mixed evenly to form a stable system. Honey not only has high nutritional value, but also can adjust the sweetness of the system. Locust bean gum has good moisturizing and antioxidant capabilities, which makes the system more stable and prolongs the storage period of the system. In the capsule liquid, vitamin C and catechins can enhance the antioxidant capacity of anthocyanins, jointly resist free radicals, protect cells from oxidative damage, promote the absorption of anthocyanins in the intestine, improve their bioavailability, and better play the health benefits of anthocyanins. Citric acid and vitamin C can adjust the pH value, create an acidic environment, and help stabilize the structure of anthocyanins. Sea buckthorn seed oil works together with anthocyanins to enhance the overall antioxidant capacity, provide a stable environment for anthocyanins, help maintain their structural stability, and prevent decomposition under adverse conditions.

[0020] The prepared capsule wall is mixed with the capsule core liquid and the emulsifier to obtain microcapsules. The capsule wall covers the capsule core liquid. As the capsule core liquid releases antioxidant substances such as citric acid, catechins, and vitamin C, citric acid, catechins, and vitamin C are released into the fruit and vegetable juice, protecting anthocyanins from the influence of temperature and light, further improving the stability of anthocyanins, and obtaining a composite fruit and vegetable juice with a high anthocyanin content.

[0021] Optionally, the method for preparing the modified starch comprises the following steps: (1) dispersing starch and sodium chloride in water, stirring at a temperature of 55-60° C. for 30-40 minutes to obtain starch milk; (2) mixing mango fiber, fructose syrup and xanthan gum, and stirring at a temperature of 75-80° C. for 1-2 hours to obtain a mixture; (3) Mixing the starch milk of step (1), the mixture of step (2) and a cross-linking agent, stirring at a temperature of 80-85° C. for 2-3 hours, filtering, and drying to obtain modified starch.

[0022] By adopting the above technical scheme, the starch has certain viscosity and film-forming properties, sodium chloride is added to increase the viscosity of the starch, and the obtained starch milk has higher viscosity; mango fiber has higher mechanical strength, high fructose corn syrup is used as a flavoring agent to improve the sweetness of the system, xanthan gum has better viscosity and antioxidant properties, xanthan gum can fill the gaps between starch granule fragments, reduce the holes on the surface of the starch system, make the starch surface smoother, and form a tighter starch structure; mango fiber is loaded in the system structure formed by starch and xanthan gum, improves the mechanical properties of the starch system, and makes the starch system have better viscosity and mechanical properties; the addition of a cross-linking agent further cross-links with the starch to improve the bonding strength of the system; the prepared modified starch is applied to the capsule wall to improve the corresponding properties of the capsule wall.

[0023] Optionally, the mass ratio of the starch, mango fiber and xanthan gum is 1:0.3-0.6:0.05-0.08.

[0024] By adopting the above technical scheme, the mass ratio of starch, mango fiber and xanthan gum is further limited within a certain range, thereby improving the structural strength, mechanical properties and viscosity of the starch system. Starch, mango fiber and xanthan gum have a synergistic effect. Xanthan gum can fill the gaps between starch granule fragments, thereby reducing the holes on the surface of the starch system and forming a tighter starch structure. Mango fiber is loaded in the system structure formed by starch and xanthan gum, thereby improving the mechanical properties of the starch system. The modified starch prepared subsequently is applied to the capsule wall to improve the corresponding properties of the capsule wall.

[0025] In summary, this application has the following beneficial effects: 1. Gum arabic, carrageenan and fucoidan are added in this application. These components are all anionic polysaccharides, which can combine with anthocyanins through electrostatic interactions to form stable complexes. At the same time, the sulfate groups in the polysaccharides can combine with anthocyanins through hydrophobic interactions to improve the stability of anthocyanins. Grape seed oil has an antioxidant effect, which further protects the activity of anthocyanins and contributes to the storage stability of anthocyanins.

[0026] 2. The composite enzyme in the present application removes suspended matter, colloidal substances and other turbid substances in the fruit juice to help preserve the fruits and vegetables. Pectinase effectively decomposes pectin substances in the fruit and vegetable juice and improves the juice yield of the fruit and vegetable juice. Cellulase degrades the macromolecular fibers in the fruit and vegetable juice into cellobiose and glucose molecules with smaller molecular weights. Glucose oxidase effectively removes oxygen and improves the preservation effect, thereby improving the system stability of the crude fruit and vegetable juice. Pectinase, cellulase and glucose oxidase are mixed in a certain proportion, and the obtained composite enzyme has a good enzymatic hydrolysis effect, and a crude fruit and vegetable juice with good stability is obtained.

[0027] 3. The low-temperature plasma sterilization of the present application can not only effectively protect the stability and biological activity of anthocyanins, but also achieve an efficient, safe and environmentally friendly sterilization effect, effectively reduce the oxidation and decomposition of anthocyanins at high temperatures, maintain their natural color and biological activity, improve the quality and nutritional value of compound fruit and vegetable juices, and extend the shelf life of compound fruit and vegetable juices. DETAILED DESCRIPTION

[0028] Preparation example of microcapsules Preparation Example 1-1 The preparation method of microcapsules comprises the following steps: (3) Peach gum, modified starch, glacial acetic acid, honey, locust bean gum and water are mixed evenly to obtain capsule wall; 10 kg peach gum, 16 kg modified starch, 3 kg glacial acetic acid, 5 kg honey, 2 kg locust bean gum and 40 kg water.

[0029] Mix 3 kg of citric acid, 2 kg of catechins, 4 kg of vitamin C and 2 kg of sea buckthorn seed oil to obtain a capsule core liquid; 3 kg of capsule wall, 1 kg of capsule core liquid and 0.3 kg of emulsifier were mixed, homogenized under high pressure and dried at 60° C. to obtain microcapsules; the particle size of the obtained microcapsules was 90-100 μm.

[0030] The pressure of high-pressure homogenization is 50 MPa; the emulsifier is Tween-80.

[0031] The preparation method of modified starch comprises the following steps: (1) Dispersing 0.9 kg of starch and 0.1 kg of sodium chloride in 1.5 L of water, stirring at 60° C. for 35 min, to obtain starch milk; (2) mixing mango fiber, 0.1 kg of fructose syrup and xanthan gum, and stirring at 80° C. for 2 h to obtain a mixture; (3) Mixing the starch milk of step (1), the mixture of step (2) and a cross-linking agent, stirring at a temperature of 85° C. for 3 h, filtering, and drying to obtain modified starch; wherein the cross-linking agent is calcium chloride.

[0032] The mass ratio of starch, mango fiber and xanthan gum is 1:0.3:0.05.

[0033] Preparation Example 1-2 The difference from Preparation Example 1-1 is that in the preparation method of modified starch, in step (2), no mango fiber is added.

[0034] Preparation Example 1-3 The difference from Preparation Example 1-1 is that in the preparation method of modified starch, in step (2), no xanthan gum is added.

[0035] Preparation Example 1-4 The difference from Preparation Example 1-1 is that the mass ratio of starch, mango fiber and xanthan gum is 1:0.6:0.08.

[0036] Preparation Example 1-5 The difference from Preparation Example 1-1 is that the mass ratio of starch, mango fiber and xanthan gum is 1:0.1:0.03. Example

[0037] Example 1 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability comprises the following steps: (1) washing and pulping the fruit and vegetable composition to obtain a mixed juice, adding a composite enzyme for enzymolysis to obtain a crude fruit and vegetable juice; the fruit and vegetable composition is selected from 2 kg of grapes, 1.5 kg of pomegranates, 2.5 kg of blueberries, 2 kg of purple cabbage and 1 kg of black wolfberry; (2) adjusting the pH value of the crude fruit and vegetable juice of step (1) to 3.7, inoculating the activated complex bacillus, and then fermenting to obtain a fermentation product, adding the stabilizing composition, stirring evenly, and filtering to obtain a mixed solution; (3) heating the mixed solution at 65° C. for 6 min to inactivate the enzyme and sterilize it to obtain a composite fruit and vegetable juice; The compound bacteria selected are Lactobacillus acidophilus; 8×10 6 CFU / g inoculated into crude fruit and vegetable juice and fermented at 39°C for 6 h to obtain fermentation products; The stabilizing composition comprises, by weight, 5 kg of gum arabic, 3 kg of carrageenan, 12 kg of grape seed oil and 2 kg of fucoidan.

[0038] The complex enzyme is composed of pectinase, cellulase and glucose oxidase in a mass ratio of 1:0.3:0.8, the enzymolysis temperature is 30°C, and the enzymolysis time is 8 hours.

[0039] The mixed liquid is placed in a reactor of a dielectric barrier discharge plasma equipment for low-temperature plasma sterilization treatment. The medium is quartz glass with a thickness of 2 mm. The low-temperature plasma sterilization treatment process is: frequency 10 kHz, electrode spacing 15 mm, voltage 80 V, treatment time 3 min, and treatment temperature is room temperature.

[0040] Example 2 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability, which is different from Example 1 in that the stabilizing composition comprises, by weight, 10 kg of gum arabic, 3 kg of carrageenan, 7 kg of grape seed oil and 5 kg of fucoidan.

[0041] The complex enzyme is composed of pectinase, cellulase and glucose oxidase in a mass ratio of 1:0.6:0.5.

[0042] Example 3 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is disclosed, which differs from Example 1 in that the stabilizing composition further comprises microcapsules, and the microcapsules are prepared in Preparation Example 1-1.

[0043] Example 4 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 3 in that the microcapsules are prepared using Preparation Example 1-2.

[0044] Example 5 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 3 in that the microcapsules are prepared using Preparation Examples 1-3.

[0045] Example 6 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 3 in that the microcapsules are prepared using Preparation Examples 1-4.

[0046] Example 7 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 3 in that the microcapsules are prepared using Preparation Examples 1-5.

[0047] Example 8 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 1 in that only gum arabic is added.

[0048] Example 9 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from that of Example 1 in that only carrageenan is added.

[0049] Example 10 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 1 in that only grape seed oil is added.

[0050] Embodiment 11 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 1 in that only fucoidan is added.

[0051] Example 12 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability, which differs from Example 1 in that the mass ratio of gum arabic, grape seed oil and fucoidan is 2:3:1.

[0052] Embodiment 13 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability, which differs from Example 1 in that the mass ratio of gum arabic, grape seed oil and fucoidan is 4:5:1.

[0053] Embodiment 14 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 1 in that only gum arabic and grape seed oil are added.

[0054] Embodiment 15 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 1 in that only gum arabic and fucoidan are added.

[0055] Example 16 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 1 in that only grape seed oil and fucoidan are added.

[0056] Comparative Example Comparative Example 1 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability is different from Example 1 in that no stabilizing composition is added.

[0057] Comparative Example 2 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability, which differs from Example 3 in that modified starch is not added.

[0058] Comparative Example 3 A method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability, which differs from Example 3 in that an equal amount of starch is used to replace the modified starch.

[0059] Performance testing The composite fruit and vegetable juices containing anthocyanins prepared in Examples 1-16 and Comparative Examples 1-3 were subjected to anthocyanin testing; 1. The determination method was based on the method described in “Distribution of anthocyanins in Aronia nigra fruits and their antioxidant activity”, Jia Xiujuan et al., Food Research and Development, 2017, 38(8): 34. The content of the composite fruit and vegetable juice was determined at 4°C in a dark environment after 0 h, 1 month, 3 months and 6 months.

[0060] 2. The mechanical properties of 200 microcapsules prepared in the embodiment and the comparative example were tested. The microcapsules were shaken in an oscillating shaker at 180 r / min and 30°C for 72 h. The surface morphology of the microcapsules was observed under a microscope. The microcapsules with incomplete capsule walls and depressions were deformed microcapsules. The deformation rate was calculated (deformation rate = number of deformed microcapsules N / total number of observed microcapsules N0 × 100%). The deformation rate was used to characterize the mechanical strength of the microcapsules.

[0061] 3. 200 microcapsules prepared in the embodiment and the comparative example were spread on glass microscope slides, with about 100 microcapsules on each slide. Excess moisture on the surface of the microcapsules was absorbed with filter paper, and a cover glass was placed on the microcapsules. After applying 20g and 50g pressure for 5 minutes, the morphology was observed under a 3D video microscope. The test results are shown in Table 1.

[0062] Table 1 Test data of embodiments and comparative examples Combining the examples and the data in Table 1, it can be seen that the composite fruit and vegetable juice containing anthocyanins prepared in Examples 1-2 has a higher anthocyanin content, wherein the anthocyanin content of Example 1 just prepared is 960 mg / kg, the anthocyanin content after 1 month is 900 mg / kg, the anthocyanin content after 3 months is 840 mg / kg, and the anthocyanin content after 6 months is 580 mg / kg, indicating that the anthocyanins in the composite fruit and vegetable juice prepared in the present application are more stable, and the stable composition is combined with anthocyanins through electrostatic interaction to form a stable complex, which better protects the anthocyanins.

[0063] Combining the examples and the data in Table 1, it can be seen that the composite fruit and vegetable juice containing anthocyanins prepared in Examples 3 and 6 has a higher anthocyanin content and good mechanical properties. Among them, the anthocyanin content of Example 31 just prepared is 1000 mg / kg, the anthocyanin content after 1 month is 950 mg / kg, the anthocyanin content after 3 months is 860 mg / kg, and the anthocyanin content after 6 months is 410 mg / kg. The deformation rate of the microcapsule is 1.5%, the deformation rate at 20g pressure is 0.8%, and the deformation rate at 50g pressure is 3.2%, indicating that the capsule wall prepared in the present application protects anthocyanins, making anthocyanins more stable. At the same time, the stabilizing composition is combined with anthocyanins through electrostatic interaction to form a stable complex. The mechanical properties of the capsule wall are good, the breakage rate is low, and the anthocyanins are better protected.

[0064] In the preparation method of modified starch in Example 4, mango fiber is not added, and in the preparation method of modified starch in Example 5, xanthan gum is not added. As can be seen from Table 1, compared with Example 3, the anthocyanin content is significantly reduced, and the deformation rate of the microcapsules is increased, indicating that mango fiber has higher mechanical strength, and cooperates with other components to improve the viscosity, film-forming property and mechanical properties of the modified starch, and subsequently improve the corresponding properties of the capsule wall; xanthan gum can fill the gaps between starch granule fragments, reduce the holes on the surface of the starch system, make the starch surface smoother, and form a tighter starch structure, thereby improving the corresponding properties of the starch.

[0065] Example 7 changes the mass ratio of starch, mango fiber and xanthan gum. As can be seen from Table 1, compared with Example 3, the test results of anthocyanin content and microcapsule breakage rate are better than those of Examples 4-5, but worse than those of Examples 1 and 6, indicating that mango fiber is loaded in the system structure formed by starch and xanthan gum, which improves the mechanical properties of the starch system. The modified starch prepared subsequently is applied to the capsule wall to improve the corresponding properties of the capsule wall.

[0066] In Examples 8-11, only gum arabic, carrageenan, grape seed oil and fucoidan were added respectively. As can be seen from Table 1, compared with Example 1, the content of anthocyanins decreased significantly. Among them, the content of anthocyanins in Example 8 just prepared was 930 mg / kg, 865 mg / kg after 1 month, 801 mg / kg after 3 months, and 536 mg / kg after 6 months, indicating that the stability of anthocyanins is not as strong as the effect of the combination of multiple components to stabilize the composition. The combination of multiple components is conducive to the storage stability of anthocyanins.

[0067] Examples 12-13 further define the mass ratio of gum arabic, grape seed oil and fucoidan. As can be seen from Table 1, compared with Example 1, the content of anthocyanins is significantly increased, wherein the content of anthocyanins in Example 12 just prepared is 967 mg / kg, 905 mg / kg after 1 month, 848 mg / kg after 3 months, and 589 mg / kg after 6 months, indicating that the combination of gum arabic, grape seed oil and fucoidan has a synergistic effect, so that the combination of each component has good stability. The combination of gum arabic, grape seed oil and fucoidan improves the stability of anthocyanins, protects the activity of anthocyanins, and contributes to the storage stability of anthocyanins.

[0068] Examples 14-16 only add two of the components of the stabilizing composition. As can be seen from Table 1, compared with Example 1, the anthocyanin content is more stable than that of Examples 8-11, but worse than that of Examples 12-13, indicating that the combination of gum arabic, grape seed oil and fucoidan in the present application has a synergistic effect, which can improve the stability of anthocyanins, protect the activity of anthocyanins, and improve the storage stability of anthocyanins.

[0069] Comparative Example 1 does not add the stabilizing composition. As can be seen from Table 1, compared with Example 1, the anthocyanin content just prepared is 930 mg / kg, the anthocyanin content after 1 month is 840 mg / kg, and the anthocyanin content after 6 months is 299 mg / kg, indicating that the stabilizing composition has good antioxidant properties and stability. The sulfate groups in various components are combined with anthocyanins through hydrophobic interactions, which improves the stability of anthocyanins, further protects the activity of anthocyanins, and contributes to the storage stability of anthocyanins.

[0070] Comparative Example 2 does not add modified starch. As can be seen from Table 1, compared with Example 3, the anthocyanin content just prepared is 932 mg / kg, the anthocyanin content is 850 mg / kg after 1 month, and the anthocyanin content is 312 mg / kg after 6 months. The microcapsule deformation rate is 4.6%, the deformation rate at 20g pressure is 4.0%, and the deformation rate at 50g pressure is 6.5%, indicating that the modified starch has good thickening properties, cross-links with peach gum, increases the viscosity and consistency of the system, helps to improve the thickness and uniformity of the subsequent microcapsule wall film, and increases the mechanical strength of the microcapsule wall film.

[0071] In Comparative Example 3, the modified starch is replaced by an equal amount of starch. As can be seen from Table 1, compared with Example 3, the test results of anthocyanin content and microcapsule breakage rate are worse than those of Example 3, indicating that the microcapsule wall prepared by adding starch has better mechanical properties, but the modified starch of the present application has excellent mechanical properties and film-forming properties, so that the microcapsule wall has better mechanical properties.

[0072] 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 composite fruit and vegetable juice with improved anthocyanin stability, characterized in that: The steps include: (1) washing and pulping the fruit and vegetable composition to obtain a mixed juice, adding a composite enzyme for enzymolysis to obtain a crude fruit and vegetable juice; (2) adjusting the pH value of the crude fruit and vegetable juice of step (1) to 3.5-3.9, inoculating the activated complex bacillus, and then fermenting to obtain a fermentation product, adding the stabilizing composition, stirring evenly, and filtering to obtain a mixed solution; (3) heating the mixed solution at 64-65°C for 4-8 minutes to inactivate the enzyme and sterilize it to obtain a composite fruit and vegetable juice; The fruit and vegetable composition comprises blueberry and other components, wherein the other components are at least two of mulberry, purple cabbage, grape, mulberry, wolfberry, blackberry, cranberry, strawberry, pomegranate, cherry, red orange, hawthorn, raspberry, purple cabbage, black corn, and purple sweet potato; The composite bacteria include one or more of Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus plantarum, Lactobacillus paracasei, and Bifidobacterium animalis; The stabilizing composition comprises one or more of gum arabic, carrageenan, grape seed oil and fucoidan.

2. The method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability according to claim 1, characterized in that: The complex enzyme consists of pectinase, cellulase and glucose oxidase in a mass ratio of 1:0.3-0.6:0.5-0.

8.

3. The method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability according to claim 1, characterized in that: In step (2), the fermentation conditions are: constant temperature fermentation at 37-40°C for 4-8 hours.

4. The method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability according to claim 1, characterized in that: The stabilizing composition comprises, by weight, 5-10 parts of gum arabic, 3-6 parts of carrageenan, 7-12 parts of grape seed oil and 2-5 parts of fucoidan.

5. The method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability according to claim 1, characterized in that: The mass ratio of the gum arabic, grape seed oil and fucoidan is 2-4:3-5:

1.

6. The method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability according to claim 1, characterized in that: In step (3), the sterilization conditions are: low-temperature plasma sterilization, the sterilization process is: frequency 5-20 kHz, electrode spacing 5-20 mm, voltage 50-100 V, treatment time 1-5 min, and treatment temperature is room temperature.

7. The method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability according to claim 1, characterized in that: The stable composition also includes microcapsules. The preparation method of the microcapsules includes the following steps: mixing peach gum, modified starch, glacial acetic acid, honey, locust bean gum and water uniformly to obtain capsule walls; Mixing citric acid, catechins, vitamin C and sea buckthorn seed oil to obtain capsule core liquid; The capsule wall, capsule core liquid and emulsifier are mixed, homogenized under high pressure and dried to obtain microcapsules.

8. The method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability according to claim 7, characterized in that: The preparation method of the modified starch comprises the following steps: (1) Dispersing starch and sodium chloride in water, stirring at a temperature of 55-60°C for 30-40 minutes to obtain starch milk; (2) mixing mango fiber, fructose syrup and xanthan gum, and stirring at a temperature of 75-80° C. for 1-2 hours to obtain a mixture; (3) Mixing the starch milk of step (1), the mixture of step (2) and the cross-linking agent, stirring at a temperature of 80-85° C. for 2-3 hours, filtering, and drying to obtain modified starch.

9. The method for preparing a blueberry composite fruit and vegetable juice with improved anthocyanin stability according to claim 8, characterized in that: The mass ratio of the starch, mango fiber and xanthan gum is 1:0.3-0.6:0.05-0.08.

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