Preparation method of high-quality apple instant solid beverage

Abstract

The invention relates to the technical field of food processing, in particular to a preparation method of a high-quality apple instant solid beverage, which comprises the following steps: selecting 12-degree BX-16-degree BX apples, pretreating, and protecting color; performing ultrasonic-assisted composite enzymatic hydrolysis, and performing high-voltage pulse electric field treatment; carrying out directional sugar conversion by electrochemical catalysis; then carrying out multi-stage concentration, and introducing nitrogen to prevent oxidation; carrying out microencapsulation granulation, and carrying out high-pressure microjet to form microcapsules; gradient freeze drying is adopted; and finally adding apple peel dietary fiber powder and tea polyphenol palmitate for function enhancement, and uniformly mixing to obtain the product. Apples with specific sugar degree and composite color protection liquid are selected through raw material pretreatment, the natural color and flavor are reserved, the content of beneficial components is increased through composite enzymolysis, the taste and nutrition are improved through directional sugar conversion, and the product stability, solubility and the like are optimized through multi-stage concentration, microencapsulation granulation and ultralow-temperature drying in the processing technology.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and specifically to a preparation method of a high-quality instant solid apple beverage. Background Art

[0002] With the increasing demand of consumers for healthy and convenient beverages, the market of instant solid apple beverages has been continuously expanding. In the selection and processing of raw materials for traditional instant solid apple beverages, they are relatively rough. Ordinary apples are often selected, and the sugar content is not strictly screened, resulting in uneven product flavors and making it difficult to fully display the natural flavor of apples. In terms of color protection, a single color protection agent is mostly used, with poor effects, and it is easy for the product to turn brown during processing and storage, affecting the color and quality.

[0003] In the enzymatic hydrolysis link, there is a lack of precise regulation. The types and proportions of enzymes are random, and the enzymatic hydrolysis conditions are not optimized, resulting in low contents of beneficial components such as active peptides and making it impossible to fully release the nutrients in apples. The sugar conversion technology is backward, and it cannot effectively adjust the ratio of fructose to glucose, making it difficult to produce fructooligosaccharides, and the taste and nutrition of the product are difficult to meet the needs of consumers for high-quality beverages.

[0004] The concentration process is simple, which is easy to cause oxidation and loss of heat-sensitive components, affecting the stability and flavor of the product. The granulation technology is single, with a low embedding rate, poor solubility of the product, and easy caking during brewing. The control of the drying process is inaccurate, the moisture and vacuum degree are not well grasped, a large amount of heat-sensitive components are lost, and the instant solubility and stability of the product are poor.

[0005] In terms of function enhancement, the types of functional components added by traditional methods are few and the proportioning is unreasonable, making it difficult to achieve the synergistic effect of multiple functional components and unable to meet the pursuit of consumers for health care functions. The quality control system is imperfect, lacking real-time monitoring and precise control of key control points. The product quality is unstable, and problems such as deterioration, increase in color difference value, and excessive total number of colonies are likely to occur during storage and transportation, seriously affecting the use experience and health and safety of consumers. Therefore, it is extremely urgent to develop a preparation method of a high-quality instant solid apple beverage that can solve the above problems. Summary of the Invention

[0006] Technical Problems to be Solved

[0007] In view of the above-mentioned disadvantages of the prior art, the present invention provides a preparation method of a high-quality instant solid apple beverage. By preprocessing raw materials, apples with a specific sugar content and a composite color protection solution are selected to retain the natural color and flavor. Composite enzymatic hydrolysis is used to increase the content of beneficial components, and directional sugar conversion is used to improve the taste and nutrition. In the processing technology, multi-stage concentration, microencapsulation granulation, and ultra-low temperature drying are respectively used to optimize the stability, solubility, etc. of the product. Function enhancement is achieved by adding multiple components to improve the nutritional value, and the quality control system ensures the product quality, ensuring stable quality during storage and transportation and guaranteeing the safety of consumers.

[0008] Technical solution

[0009] To achieve the above object, the present invention is realized through the following technical solutions:

[0010] A preparation method of a high-quality instant solid apple beverage, the preparation method comprising the following steps:

[0011] (1) Raw material pretreatment: Select apples with a sugar content of 12°BX to 16°BX measured by a refractometer at 20°C, wash, peel and cut into pieces, and soak in a composite color protection solution for 20 - 30 minutes. The mass fraction of L-ascorbic acid in the composite color protection solution is 0.45% - 0.55%, the mass fraction of sodium phytate is 0.028% - 0.032%, and the temperature of the color protection solution is controlled at 4 - 8°C;

[0012] (2) Composite enzymatic hydrolysis: Mix the color-protected apple pieces with an enzyme and perform ultrasonic-assisted enzymatic hydrolysis. The mass ratio of aldolase type B to glucose-fructose oxidoreductase in the enzyme is 1:0.04 - 1:0.06. The enzymatic hydrolysis conditions are pH 4.5 - 5.5, temperature 45 - 55°C, ultrasonic power 300 - 500W, enzymatic hydrolysis time 40 - 60 minutes. The enzymatic hydrolysis solution is treated by high-voltage pulsed electric field, and the electric field strength is 30 - 50 kV / cm;

[0013] (3) Directed sugar conversion: Use electrocatalytic technology to adjust the molar ratio of fructose to glucose to 1:1.2 - 1:1.5, and simultaneously generate fructooligosaccharides, with a conversion rate of not less than 85%;

[0014] (4) Multi-stage concentration: In the first stage, concentrate to a solid content of 30% - 35% under a pressure of 0.6 - 0.8 MPa, and in the second stage, concentrate to a solid content of 50% - 55% under a pressure of 0.3 - 0.5 MPa. Nitrogen is continuously introduced during the concentration process to prevent oxidation;

[0015] (5) Microencapsulation granulation: Mix the concentrated solution with β-cyclodextrin at a mass ratio of 1:0.18 - 1:0.22, and form microcapsule particles with a particle size not exceeding 50 μm through high-pressure microfluidization technology, with an embedding rate of not less than 92%;

[0016] (6) Ultra-low temperature drying: Adopt a gradient freeze-drying process, with the temperature dropping from -35°C to -45°C, the vacuum degree not exceeding 10 Pa, the moisture content at the end of drying not exceeding 3.5%, and far-infrared assisted heating during the drying process, with a radiation intensity of 150 - 200 W / m 2 , and the heating time is 20 - 30 minutes;

[0017] (7) Functional enhancement: Add apple peel dietary fiber powder with a mass fraction of 5%-8% and tea polyphenol palmitate with a mass fraction of 0.028%-0.032% to the final product. The particle size of the apple peel dietary fiber powder does not exceed 80 mesh and its water holding capacity is not less than 8 g / g, and it is evenly mixed through a fluidized bed.

[0018] Further, the composite enzymatic hydrolysis process in step (2) includes:

[0019] During the first-stage enzymatic hydrolysis, the temperature is maintained at 48-52°C and the ultrasonic power is set at 380-420 W;

[0020] During the second-stage enzymatic hydrolysis, the temperature is switched to 8-10°C every 10 minutes and maintained for 2 minutes to inhibit browning;

[0021] The enzymatic hydrolysate is filtered through a ceramic membrane with a molecular weight cut-off of 10 kDa, and the active peptide component with a molecular weight not exceeding 5 kDa is retained.

[0022] Even further, the microencapsulation granulation in step (5) adopts a double embedding technology, including:

[0023] Primary embedding: β-cyclodextrin and the concentrated solution are stirred at a constant temperature of 48-52°C for 50-70 minutes at a mass ratio of 1:4.8-1:5.2;

[0024] Secondary embedding: Add a sodium alginate-Ca 2 + cross-linking system, and generate core-shell structure particles through a microfluidic chip, with the shell layer thickness of 10-15 μm.

[0025] Even further, the preparation of the apple peel dietary fiber powder includes:

[0026] After the apple peel is washed with a citric acid solution with a mass fraction of 0.48%-0.52%, it is treated with ultra-high pressure homogenization at a pressure of 600-800 bar and cellulase with an enzyme activity of 180-220 U / g;

[0027] Dynamic drying: First, dry with hot air at 58-62°C until the moisture content is 14%-16%, and then dry with vacuum microwave until the moisture content does not exceed 5%, with a microwave power of 780-820 W and a vacuum degree of -0.085 MPa to -0.095 MPa;

[0028] After being crushed to a particle size not exceeding 80 mesh, impurities are removed by electrostatic separation to obtain a functional powder with a dietary fiber purity not less than 85%.

[0029] Even further, the dissolution performance optimization is also included in step (5), specifically:

[0030] Add octenyl succinic anhydride starch ester with a mass fraction of 0.4%-1.3% as a dispersant;

[0031] Use a three-fluid spray drying tower for drying, with an inlet air temperature of 175-185°C, an outlet air temperature of 80-90°C, and an atomization pressure of 1.2-1.5 MPa;

[0032] The wetting time of the final product does not exceed 15 seconds, and the dispersion stability is not less than 98%.

[0033] Furthermore, the preparation method further includes a sensory quality improvement process, specifically the following steps:

[0034] (a) Add natural apple essence microcapsules with a mass fraction of 0.015%-0.025% to the concentrated liquid with a solid content of 50%-55% during the concentration stage. The essence microcapsules are encapsulated with a composite wall material of β-cyclodextrin and sodium alginate, with an encapsulation rate of not less than 95% and a particle size distribution of 20-50 μm;

[0035] (b) Extract the volatile components of apple flowers using a supercritical carbon dioxide extraction process, with an extraction pressure of 20-30 MPa, a temperature of 35-45°C, an extraction time of 60-120 minutes, and collect the concentrated liquid of the volatile components;

[0036] (c) Compound the concentrated liquid obtained in step (b) into the final product at a mass ratio of 0.04%-0.06%. The umami value detected by an electronic tongue is not less than 8.5, and the fruit aroma intensity in the sensory evaluation is not less than 8 points.

[0037] Furthermore, the functional enhancement includes the synergistic effect of the following components:

[0038] Add nano-tricalcium phosphate with a mass fraction of 0.08%-0.12%, with a particle size of 50-100 nm. The calcium ion sustained release rate is not less than 80% through ion exchange modification treatment, and the calcium dissolution amount is 120-150 mg / 100 g;

[0039] Compound inulin-type fructooligosaccharides with a mass fraction of 2%-4%, with a degree of polymerization of 3-5 and a prebiotic content of not less than 90%, and prepare a premix by spray drying method;

[0040] Use an in vitro simulated digestion model to verify that the polyphenol retention rate is not less than 75%, among which the ABTS radical scavenging activity is 85%-90%, and the DPPH radical scavenging activity is 78%-85%.

[0041] Furthermore, the preparation method further includes a quality control system, and the quality control system includes the following technical features:

[0042] The on-line near-infrared spectroscopy detection device monitors the solid content in real time. The detection wavelength range is 900 - 1700 nm. The deviation of the solid content is controlled within the range of ±0.3% - ±0.5%. The detection frequency is to collect data once every 10 seconds;

[0043] Based on the HACCP system, key control points are set: the residual activity of polyphenol oxidase in the enzymolysis process is not higher than 5%, and the water activity in the drying process is not higher than 0.35;

[0044] The stability of the final product is verified by an accelerated experiment: stored for 90 days under the conditions of temperature 40°C ± 2°C and relative humidity 75% ± 5%, the color difference value ΔE is 3.0 - 3.5, and the growth rate of the total number of colonies is not higher than 15%.

[0045] Beneficial effects

[0046] Adopting the technical solution provided by the present invention, compared with the known public technology, it has the following

[0047] Beneficial effects:

[0048] First, in the raw material pretreatment link of the present invention, apples with a specific sugar content are selected and a specific composite color protection solution is used, which can retain the natural color and flavor of apples to the greatest extent. At the same time, when performing composite enzymolysis, the enzyme ratio, enzymolysis conditions and subsequent treatments are precisely regulated, which can increase the content of beneficial components such as active peptides. Territorial directional sugar conversion adjusts the ratio of fructose to glucose and generates fructooligosaccharides, improving the taste and nutrition, and enhancing the internal quality of the product in many aspects.

[0049] Second, the present invention reduces quality loss by multi-stage concentration with segmented pressure control and purging with nitrogen to prevent oxidation. The microencapsulation granulation adopts a double embedding technology to increase the embedding rate. At the same time, a dispersant is added and the drying conditions are optimized to improve the solubility of the product. The ultra-low temperature drying adopts gradient freezing combined with far-infrared heating to precisely control the moisture and vacuum degree, reducing the loss of heat-sensitive components and ensuring the stability and instant solubility of the product.

[0050] Third, in the function strengthening step of the present invention, a variety of beneficial components are added to synergistically improve the nutritional value and health care function of the product. At the same time, through the quality control system, by real-time monitoring of the solid content, setting key control points and verifying the stability through accelerated experiments, it is ensured that the product has reliable quality and high stability, and the quality is stable during storage and transportation, guaranteeing the safety of consumers during use. Specific embodiments

[0051] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will, in combination with the embodiments of the present invention, clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are some, rather than all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0052] The following further describes the present invention in combination with embodiments.

[0053] Example 1

[0054] Raw material pretreatment: Select apples with a sugar content of 14° BX measured by a refractometer at 20°C, wash, peel, and cut them into pieces, and soak them in a composite color protection solution (L-ascorbic acid mass fraction 0.45%, sodium phytate mass fraction 0.028%, temperature 4°C) for 30 minutes.

[0055] Composite enzymatic hydrolysis: Mix the color-protected apple pieces with an enzyme (mass ratio of type B aldolase to glucose-fructose oxidoreductase 1:0.04). The temperature for the first-stage enzymatic hydrolysis is 48°C and the ultrasonic power is 380 W; for the second-stage enzymatic hydrolysis, the temperature is switched to 8°C every 10 minutes and maintained for 2 minutes. The overall enzymatic hydrolysis is carried out at pH 4.5, temperature 45°C, and ultrasonic power 300 W for 40 minutes. The enzymatic hydrolysate is treated with a high-voltage pulsed electric field of 30 kV / cm and then filtered through a ceramic membrane with a molecular weight cut-off of 10 kDa to retain the bioactive peptide component with a molecular weight not exceeding 5 kDa.

[0056] Directed sugar conversion: Using electrochemical catalysis technology, adjust the molar ratio of fructose to glucose to 1:1.2, with a conversion rate of 86%.

[0057] Multi-stage concentration: Concentrate to a solid content of 30% at a pressure of 0.6 MPa in the first stage; concentrate to a solid content of 50% at a pressure of 0.3 MPa in the second stage. Nitrogen is passed throughout the concentration process.

[0058] Microencapsulation granulation: Mix the concentrated solution with β-cyclodextrin at a mass ratio of 1:0.18. During primary embedding, β-cyclodextrin and the concentrated solution are mixed at a mass ratio of 1:4.8 and stirred at a constant temperature of 48°C for 70 minutes; for secondary embedding, add a sodium alginate-Ca 2 + cross-linking system to generate core-shell structured particles with a shell thickness of 10 μm through a microfluidic chip. Add a mass fraction of 0.4% octenyl succinic anhydride starch ester and dry it in a three-fluid spray drying tower (inlet air temperature 175°C, outlet air temperature 80°C, atomization pressure 1.2 MPa).

[0059] Ultra-low temperature drying: The gradient freeze-drying process is adopted, with the temperature decreasing from -35°C to -45°C, the vacuum degree being 8 Pa, the moisture content at the drying end point being 3.0%, and far-infrared assisted heating is combined (radiation intensity 150 W / m 2 , and the heating time is 30 minutes).

[0060] Function enhancement: Add apple peel dietary fiber powder with a mass fraction of 5% (particle size not exceeding 80 mesh, water holding capacity 8.0 g / g), tea polyphenol palmitate with a mass fraction of 0.028%, nano-tricalcium phosphate with a mass fraction of 0.08% (particle size 50 nm, calcium ion slow release rate 80%, calcium dissolution amount 120 mg / 100 g), and inulin-type fructooligosaccharide with a mass fraction of 2% (degree of polymerization 3, prebiotic content 90%) to the final product, and mix evenly through a fluidized bed.

[0061] Sensory quality improvement: Add natural apple essence microcapsules with a mass fraction of 0.015% (encapsulation rate 95%, particle size distribution 20 - 30 μm) to the concentrated liquid with a solid content of 50% during the concentration stage. Extract the volatile components of apple flowers by the supercritical carbon dioxide extraction process (extraction pressure 20 MPa, temperature 35°C, extraction time 60 minutes), and compound them into the final product according to a mass ratio of 0.04%.

[0062] Example 2

[0063] Raw material pretreatment: Select apples with a sugar degree of 16° BX at 20°C. After washing, peeling, and cutting into pieces, soak them in a composite color protection solution (L-ascorbic acid mass fraction 0.55%, sodium phytate mass fraction 0.032%, temperature 8°C) for 20 minutes.

[0064] Compound enzymatic hydrolysis: Mix the apple pieces with the enzyme (mass ratio of aldolase type B to glucose-fructose oxidoreductase 1:0.06). The temperature of the first-stage enzymatic hydrolysis is 52°C, and the ultrasonic power is 420 W; the temperature is switched to 10°C every 10 minutes and maintained for 2 minutes in the second-stage enzymatic hydrolysis. Enzymatic hydrolysis is carried out at pH 5.5, temperature 55°C, and ultrasonic power 500 W for 60 minutes. The enzymatic hydrolysate is treated by a high-voltage pulsed electric field of 50 kV / cm and filtered through a ceramic membrane.

[0065] Directed sugar conversion: Use electrocatalytic technology to adjust the molar ratio of fructose to glucose to 1:1.5, with a conversion rate of 87%.

[0066] Multi-stage concentration: Concentrate to a solid content of 35% at a pressure of 0.8 MPa in the first stage; concentrate to a solid content of 55% at a pressure of 0.5 MPa in the second stage, and pass nitrogen.

[0067] Microencapsulation granulation: The concentrated solution and β-cyclodextrin are mixed at a mass ratio of 1:0.22. During primary encapsulation, β-cyclodextrin and the concentrated solution are stirred at a mass ratio of 1:5.2 at a constant temperature of 52 °C for 50 minutes; for secondary encapsulation, a sodium alginate-Ca 2 + crosslinking system is added to form core-shell structured particles with a shell thickness of 15 μm. Octenyl succinic anhydride starch ester with a mass fraction of 1.3% is added and dried in a three-fluid spray drying tower (inlet air temperature 185 °C, outlet air temperature 90 °C, atomization pressure 1.5 MPa).

[0068] Ultra-low temperature drying: Gradient freeze-drying, the temperature is reduced from -35 °C to -45 °C, the vacuum degree is 9 Pa, the moisture content at the end of drying is 3.3%, with far-infrared assisted heating (radiation intensity 200 W / m 2 and heating time 20 minutes).

[0069] Function enhancement: Apple peel dietary fiber powder with a mass fraction of 8% (particle size not exceeding 80 mesh, water holding capacity 8.5 g / g), tea polyphenol palmitate with a mass fraction of 0.032%, nano-tricalcium phosphate with a mass fraction of 0.12% (particle size 100 nm, calcium ion slow release rate 82%, calcium dissolution amount 140 mg / 100 g), and inulin-type fructooligosaccharide with a mass fraction of 4% (degree of polymerization 5, prebiotic content 91%) are added and mixed in a fluidized bed.

[0070] Sensory quality improvement: During the concentration stage, natural apple essence microcapsules with a mass fraction of 0.025% (encapsulation rate 96%, particle size distribution 40 - 50 μm) are added to the concentrated solution with a solid content of 55%. The volatile components of apple flowers are extracted by supercritical carbon dioxide extraction process (extraction pressure 30 MPa, temperature 45 °C, extraction time 120 minutes) and compounded into the final product at a mass ratio of 0.06%.

[0071] Example 3

[0072] Raw material pretreatment: Apples with a sugar content of 15 °BX at 20 °C are selected. After washing, peeling and cutting into pieces, they are soaked in a compound color protection solution (L-ascorbic acid mass fraction 0.5%, sodium phytate mass fraction 0.03%, temperature 6 °C) for 25 minutes.

[0073] Compound enzymatic hydrolysis: The apple pieces are mixed with enzymes (the mass ratio of type B aldolase to glucose-fructose oxidoreductase is 1:0.05). The temperature for the first-stage enzymatic hydrolysis is 50 °C and the ultrasonic power is 400 W; for the second-stage enzymatic hydrolysis, the temperature is switched to 9 °C every 10 minutes and maintained for 2 minutes. Enzymatic hydrolysis is carried out at pH 5.0, temperature 50 °C and ultrasonic power 400 W for 50 minutes. The enzymatic hydrolysate is treated by a high-voltage pulsed electric field of 40 kV / cm and filtered through a ceramic membrane.

[0074] Directed sugar conversion: Using electrocatalytic technology to adjust the molar ratio of fructose to glucose to 1:1.4, with a conversion rate of 88%.

[0075] Multi-stage concentration: In the first stage, concentrate to a solids content of 33% under a pressure of 0.7 MPa; in the second stage, concentrate to a solids content of 53% under a pressure of 0.4 MPa, and pass nitrogen.

[0076] Microencapsulation granulation: Mix the concentrated solution with β-cyclodextrin at a mass ratio of 1:0.2. During primary embedding, β-cyclodextrin and the concentrated solution are mixed at a mass ratio of 1:5 and stirred at a constant temperature of 50 °C for 60 minutes; for secondary embedding, add a sodium alginate-Ca 2 + cross-linking system to form core-shell structured particles with a shell thickness of 12 μm. Add octenyl succinic anhydride starch ester with a mass fraction of 0.8% and dry in a three-fluid spray drying tower (inlet air temperature 180 °C, outlet air temperature 85 °C, atomization pressure 1.3 MPa).

[0077] Ultra-low temperature drying: Gradient freeze-drying, the temperature drops from -35 °C to -45 °C, the vacuum degree is 7 Pa, the moisture content at the end of drying is 3.1%, with far-infrared assisted heating (radiation intensity 180 W / m 2 、heating time 25 minutes).

[0078] Function enhancement: Add apple peel dietary fiber powder with a mass fraction of 6% (particle size not exceeding 80 mesh, water holding capacity 8.3 g / g), tea polyphenol palmitate with a mass fraction of 0.03%, nano-tricalcium phosphate with a mass fraction of 0.1% (particle size 75 nm, calcium ion slow release rate 81%, calcium dissolution amount 130 mg / 100 g), and inulin-type fructooligosaccharide with a mass fraction of 3% (degree of polymerization 4, prebiotic content 90%), and mix in a fluidized bed.

[0079] Sensory quality improvement: Add natural apple essence microcapsules with a mass fraction of 0.02% (encapsulation rate 95%, particle size distribution 30 - 40 μm) to the concentrated solution with a solids content of 53% during the concentration stage. Extract the volatile components of apple flowers using supercritical carbon dioxide extraction process (extraction pressure 25 MPa, temperature 40 °C, extraction time 90 minutes) and compound them into the final product at a mass ratio of 0.05%.

[0080] Comparative Example 1 (without composite enzymatic hydrolysis optimization)

[0081] Raw material pretreatment: The same as in Example 1.

[0082] Compound enzymatic hydrolysis: The color-protected apple pieces were mixed with an enzyme (the mass ratio of type B aldolase to glucose-fructose oxidoreductase was 1:0.05), and enzymatically hydrolyzed for 50 minutes at pH 5.0, a temperature of 50 °C, and an ultrasonic power of 400 W. The enzymatic hydrolysate was treated with a high-voltage pulsed electric field of 40 kV / cm, and the temperature control of the front and rear enzymatic hydrolysis and ceramic membrane filtration were not carried out. The subsequent steps were the same as those in Example 1.

[0083] Comparative Example 2 (without optimizing microencapsulation granulation)

[0084] Raw material pretreatment - multi-stage concentration: The same as in Example 1.

[0085] Microencapsulation granulation: The concentrated solution was mixed with β-cyclodextrin at a mass ratio of 1:0.2. The double embedding technology was not adopted, and octenyl succinic anhydride starch ester was not added. It was dried with an ordinary spray drying tower (inlet air temperature 180 °C, outlet air temperature 85 °C). The subsequent steps were the same as those in Example 1.

[0086] Comparative Example 3 (without functional enhancement and sensory quality improvement)

[0087] Raw material pretreatment - cryogenic drying: The same as in Example 1.

[0088] Subsequent treatment: Apple peel dietary fiber powder, tea polyphenol palmitate, nano-scale tricalcium phosphate, inulin-type fructooligosaccharides, etc. were not added for functional enhancement, and natural apple essence microcapsules and apple flower volatile components were not added for sensory quality improvement.

[0089]

[0090]

[0091]

[0092] From the comparison between the examples and the comparative examples, it can be seen that the preparation method of the present invention has significant advantages. The optimization of compound enzymatic hydrolysis can effectively increase the content of active peptides; the optimization of microencapsulation granulation greatly improves the microcapsule embedding rate and the dissolution performance of the product; the functional enhancement makes the product rich in various functional components and improves the nutritional value; the sensory quality improvement significantly enhances the flavor and taste of the product; the processes such as cryogenic drying and multi-stage concentration cooperate to ensure the stability of the product. Generally speaking, this preparation method can produce an apple instant solid beverage with excellent quality, showing excellent performance in terms of the retention of active ingredients, solubility, flavor, stability and functionality, and having obvious competitive advantages compared with the unoptimized preparation methods, and having good market application prospects.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a high-quality instant solid apple beverage, characterized in that, The preparation method comprises the following steps: (1) Raw material pretreatment: Select apples with a sugar degree of 12°BX to 16°BX measured by a refractometer at 20°C. After cleaning, peel and cut them into pieces, and soak them in a composite color protection solution for 20 - 30 minutes. The mass fraction of L-ascorbic acid in the composite color protection solution is 0.45% - 0.55%, the mass fraction of sodium phytate is 0.028% - 0.032%, and the temperature of the color protection solution is controlled at 4 - 8°C; (2) Composite enzymatic hydrolysis: Mix the color-protected apple pieces with enzymes and carry out ultrasonic-assisted enzymatic hydrolysis. The mass ratio of aldolase type B to glucose-fructose oxidoreductase in the enzymes is 1:0.04 - 1:0.

06. The enzymatic hydrolysis conditions are pH 4.5 - 5.5, temperature 45 - 55°C, ultrasonic power 300 - 500W, enzymatic hydrolysis time 40 - 60 minutes. The enzymatic hydrolysate is treated by high-voltage pulsed electric field with an electric field strength of 30 - 50 kV / cm; (3) Directed sugar conversion: Use electrocatalytic technology to adjust the molar ratio of fructose to glucose to 1:1.2 - 1:1.5, and simultaneously generate fructooligosaccharides with a conversion rate of not less than 85%; (4) Multi-stage concentration: In the first stage, concentrate to a solid content of 30% - 35% under a pressure of 0.6 - 0.8 MPa, and in the second stage, concentrate to a solid content of 50% - 55% under a pressure of 0.3 - 0.5 MPa. Nitrogen is continuously introduced during the concentration process to prevent oxidation; (5) Microencapsulation granulation: Mix the concentrated solution with β-cyclodextrin at a mass ratio of 1:0.18 - 1:0.22, and form microcapsule particles with a particle size not exceeding 50 μm through high-pressure microfluidization technology, with an encapsulation rate of not less than 92%; (6) Ultra-low temperature drying: The gradient freeze-drying process is adopted, with the temperature decreasing from -35°C to -45°C, the vacuum degree not exceeding 10 Pa, the moisture content at the end of drying not exceeding 3.5%, and far-infrared auxiliary heating is used during the drying process, with the radiation intensity being 150 - 200 W / m 2 , and the heating time is 20 - 30 minutes; (7) Function enhancement: Add 5% - 8% of apple peel dietary fiber powder and 0.028% - 0.032% of tea polyphenol palmitate by mass fraction to the final product. The particle size of the apple peel dietary fiber powder does not exceed 80 mesh and the water holding capacity is not less than 8 g / g, and mix them evenly through a fluidized bed.

2. The preparation method of a high-quality instant solid apple beverage according to claim 1, characterized in that, The composite enzymatic hydrolysis process in step (2) includes: Maintain the temperature at 48 - 52°C and set the ultrasonic power to 380 - 420W during the first-stage enzymatic hydrolysis; During the second-stage enzymatic hydrolysis, switch the temperature to 8 - 10°C every 10 minutes and maintain it for 2 minutes to inhibit browning; The enzymatic hydrolysate is filtered through a ceramic membrane with a molecular weight cut-off of 10 kDa, and the active peptide component with a molecular weight not exceeding 5 kDa is retained.

3. The preparation method of a high-quality instant solid apple beverage according to claim 1, wherein, The microencapsulation granulation in step (5) adopts a double embedding technology, including: Primary embedding: β-cyclodextrin and the concentrated solution are stirred at a constant temperature of 48 - 52°C for 50 - 70 minutes at a mass ratio of 1:4.8 - 1:5.2; Secondary embedding: Add a sodium alginate-Ca crosslinking system with a mass fraction of 0.09%-0.11%, and generate core-shell structured particles through a microfluidic chip, with the shell layer thickness being 10-15 μm. 2 ​ 4. The preparation method of a high-quality instant solid apple beverage according to claim 1, characterized in that The preparation of the apple peel dietary fiber powder includes: Wash apple peels with a citric acid solution with a mass fraction of 0.48% - 0.52%, and treat them with a cellulose enzyme with an enzyme activity of 180 - 220 U / g by ultra-high pressure homogenization at a pressure of 600 - 800 bar; Dynamic drying: First, dry with hot air at 58 - 62°C until the moisture content is 14% - 16%, and then dry with vacuum microwave until the moisture content does not exceed 5%. The microwave power is 780 - 820W, and the vacuum degree is -0.085 MPa to -0.095 MPa; After being crushed to a particle size not exceeding 80 mesh, impurities are removed by electrostatic separation to obtain a functional powder with a dietary fiber purity of not less than 85%.

5. The preparation method of a high-quality instant solid apple beverage according to claim 1, characterized in that, The step (5) also includes optimizing the dissolution performance, specifically: Adding 0.4%-1.3% by mass of octenyl succinic anhydride starch ester as a dispersant; Using a three-fluid spray drying tower for drying, with an inlet air temperature of 175-185°C, an outlet air temperature of 80-90°C, and an atomization pressure of 1.2-1.5 MPa; The wetting time of the final product does not exceed 15 seconds, and the dispersion stability is not less than 98%.

6. The preparation method of a high-quality instant solid apple beverage according to claim 1, characterized in that, This preparation method also includes a sensory quality improvement process, specifically the following steps: (a) Adding 0.015%-0.025% by mass of natural apple essence microcapsules to the concentrated liquid with a solid content of 50%-55% during the concentration stage. The essence microcapsules are embedded with a composite wall material of β-cyclodextrin and sodium alginate, with an embedding rate of not less than 95% and a particle size distribution of 20-50 μm; (b) Extracting the volatile components of apple flowers by a supercritical carbon dioxide extraction process, with an extraction pressure of 20-30 MPa, a temperature of 35-45°C, and an extraction time of 60-120 minutes, and collecting the concentrated liquid of the volatile components; (c) Compounding the concentrated liquid obtained in step (b) into the final product at a mass ratio of 0.04%-0.06%. The umami value detected by an electronic tongue is not less than 8.5, and the fruit aroma intensity in the sensory evaluation is not less than 8 points.

7. The preparation method of a high-quality instant solid apple beverage according to claim 1, characterized in that, The functional enhancement includes the synergistic effect of the following components: Adding 0.08%-0.12% by mass of nano-tricalcium phosphate with a particle size of 50-100 nm. Through ion exchange modification treatment, the calcium ion slow release rate is not less than 80%, and the calcium dissolution amount is 120-150 mg / 100 g; Compounding 2%-4% by mass of inulin-type fructooligosaccharides with a degree of polymerization of 3-5 and a prebiotic content of not less than 90%, and preparing a premix by spray drying; Using an in vitro simulated digestion model to verify that the polyphenol retention rate is not less than 75%, where the ABTS radical scavenging activity is 85%-90%, and the DPPH radical scavenging activity is 78%-85%.

8. The preparation method of a high-quality instant solid apple beverage according to claim 1, characterized in that, This preparation method also includes a quality control system, and the quality control system includes the following technical features: An on-line near-infrared spectroscopy detection device monitors the solid content in real time, with a detection wavelength range of 900-1700 nm. The deviation of the solid content is controlled within the range of ±0.3%-±0.5%, and the detection frequency is to collect data every 10 seconds; Setting critical control points based on the HACCP system: the residual activity of polyphenol oxidase in the enzymolysis process is not higher than 5%, and the water activity in the drying process is not higher than 0.35; The stability of the final product is verified by an accelerated experiment: stored for 90 days under the conditions of a temperature of 40°C±2°C and a relative humidity of 75%±5%, the color difference value ΔE is 3.0-3.5, and the growth rate of the total number of colonies is not higher than 15%.

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