Preparation method and application of corn straw beverage

Abstract

The invention relates to a preparation method and application of a corn straw beverage, belongs to the technical field of plant resource processing, and solves the technical problem of activity loss caused by easy oxidative degradation of flavonoid compounds in a corn straw water extract. According to the technical scheme, the method comprises the following steps: crushing corn straws, soaking in water, performing heat extraction for multiple times to obtain an extracting solution, performing rough filtration and centrifugation, and concentrating to obtain a water extracting solution; and mixing the water extract, sucralose, citric acid, potassium sorbate and purified water to prepare a beverage, sterilizing and filling. Flavonoid compounds are embedded through a potato starch nanoparticle and beta-cyclodextrin composite carrier, a sodium alginate-chitosan microcapsule double-layer coating and microcapsule jelly particle preparation technology is combined, a gel network is formed by compounding kappa-carrageenan and konjac glucomannan, and the embedding stability and release controllability of active ingredients are improved. The beverage prepared by the method has both herbal flavor and crisp and tender taste of jelly particles, effectively delays degradation of flavonoid compounds, and is suitable for being applied to development of functional plant beverages.

Description

Technical Field

[0001] The invention belongs to the technical field of plant resource processing, and more specifically, relates to a preparation method and application of a corn straw beverage. Background Art

[0002] Corn stalks, as agricultural byproducts, contain active ingredients such as flavonoids and polysaccharides, but their comprehensive utilization still faces technical bottlenecks. During the processing of traditional corn stalk extracts, flavonoids are easily degraded by heat, light and oxidation, resulting in a significant reduction in the content of active ingredients in the finished beverage. For example, during sterilization and long-term storage of water extracts, the loss rate of flavonoids can reach more than 40% due to the unstable molecular structure, which directly affects the functional characteristics of the product. In addition, the single encapsulation technology used in the prior art to protect active ingredients has obvious defects: although β-cyclodextrin inclusion complexes can improve solubility, the encapsulation rate is usually less than 75%, and high temperatures during spray drying can easily destroy heat-sensitive components; although sodium alginate microcapsules have a sustained release effect, the mechanical strength of the capsule wall is insufficient and it is easy to break and fail in an acidic beverage environment.

[0003] In terms of beverage formula design, directly adding microcapsule particles can easily lead to deterioration of sensory quality. Uneven distribution of microcapsule particle size will lead to poor suspension stability of beverages, and particles will aggregate and precipitate during storage, resulting in a gritty feeling when drinking. At the same time, existing gel carriers such as jelly formed by single carrageenan have a hard texture, and when combined with microcapsules, they are prone to capsule leakage due to low water retention. More importantly, flavonoids and other ingredients in the beverage matrix (such as organic acids and preservatives) may undergo synergistic degradation reactions. For example, citric acid accelerates the hydrolysis of flavonoid glycoside bonds during sterilization, further exacerbating activity loss.

[0004] Existing technologies attempt to reduce oxidation risks through low-temperature concentration and inert gas protection, but the equipment is expensive and difficult to apply on a large scale. In addition, the interaction between corn straw polysaccharides and colloids has not been well studied, and the colloidal properties of its own arabinoxylan have not been effectively utilized to build a stable delivery system, which restricts the gradient release effect of functional ingredients. The above problems together lead to the common technical defects of existing corn straw beverages, such as low active ingredient retention rate, rough taste, and short functional timeliness. Summary of the invention

[0005] An object of the present invention is to address at least the above-mentioned disadvantages and to provide at least the advantages which will be described hereinafter.

[0006] The present invention provides a method for preparing a corn straw beverage, aiming to solve the following technical problems: During the processing of traditional corn straw extracts, flavonoids are easily degraded under the influence of heat, light, and oxidation, resulting in low extraction efficiency of active ingredients (such as flavonoids) in the water extract of corn straw, and they are prone to oxidative degradation during sterilization and storage, leading to a decline in the functionality of the beverage; directly adding the extract to the beverage formula easily causes problems such as a bitter taste and poor stability.

[0007] Flavonoids in the water extract of corn straw are easily oxidized and degraded during processing and storage, resulting in a loss rate of active ingredients as high as over 40%. Existing embedding technologies (such as β-cyclodextrin) have a low embedding rate (<75%), and they cannot resist the damage of acidic environments or high-temperature spray drying.

[0008] During the preparation of the carrier, the addition amount of citric acid and reaction conditions (such as pH, temperature) are not precisely controlled, which easily leads to over-esterification or ineffective side reactions caused by residual acid catalysis, affecting the stability of the carrier and the flavonoid embedding efficiency.

[0009] Probiotics (such as Lactobacillus plantarum) are easily damaged during the sterilization and storage of beverages, and flavonoids and probiotics cannot be delivered synergistically, resulting in limited hypolipidemic effects.

[0010] Directly adding microcapsules to the beverage easily causes aggregation and precipitation, resulting in a rough taste (sandiness), and the water retention rate of the gel network is low, unable to achieve a gradient release of functional ingredients.

[0011] A preparation method of a corn straw beverage provided by the present invention includes the following steps: Step (1): Wash the corn straw, dry it, and crush it. Step (2): Add pure water according to a solid-liquid ratio of 1:12 - 16, soak for 12 - 15 hours to obtain a corn straw mixture. Step (3): Extract the corn straw mixture under a water bath condition of 80 - 100 °C, extract for 1 - 2 hours each time, repeat the extraction 1 - 3 times, and combine the extracts. Step (4): Coarsely filter the combined extract, and then centrifuge to obtain the supernatant. Step (5): Concentrate the supernatant to obtain a water extract of corn straw. Step (6): The mixed beverage formulation includes 78 - 700 mg / mL of the water extract of corn straw, 0.30 - 0.40 mg / mL of sucralose, 0.32 - 0.40 mg / mL of citric acid, 0.20 - 0.28 mg / mL of potassium sorbate, and the balance is pure water. Mix evenly. Step (7): Sterilize and fill the mixed solution to obtain the finished beverage.

[0012] Preferably, in step (1), it is crushed to a particle size of ≤5 mm; in step (2), the solid-liquid ratio is 1:14 and it is soaked for 12 hours; in step (3), it is extracted under the condition of a 100°C water bath, each extraction lasts for 1 hour, and the extraction is repeated 3 times; in step (4), it is centrifuged at 3000 r / min for 10 minutes to obtain the supernatant; in step (5), the supernatant is concentrated to 1 / 3 of the original extraction volume to obtain the aqueous extract of corn straw; the mixed and formulated beverage in step (6) includes 700 mg / mL of the aqueous extract of corn straw, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, and 0.28 mg / mL of potassium sorbate; in step (7), the mixed solution is sterilized by ultraviolet light for 10 - 15 minutes and filled into sterilized glass bottles to obtain the finished beverage.

[0013] Preferably, in step (5) of the present invention, a carrier is further included, and the preparation steps of the carrier are as follows: Mix potato starch nanoparticles (particle size 50 nm to 100 nm) and β-cyclodextrin in a mass ratio of 1:1 - 1.5 to obtain a first mixture. Add a citric acid solution with a mass concentration of 3% to the first mixture, and the addition amount of the citric acid solution is 5 - 8% of the total mass of the first mixture. Stir and react the mixed system. After the reaction ends, centrifuge to remove free citric acid and dry to obtain the carrier. Mix the aqueous extract of corn straw and the carrier in a volume-to-mass ratio of 4 ml:1 g, and treat it at an ultrasonic frequency of 45 kHz and a power of 150 W for 20 minutes to embed the flavonoids in the aqueous extract of corn straw into the pores, with an embedding rate of ≥90%; then prepare embedded particles with a particle size of 10 - 30 μm by spray drying, and control the moisture content to ≤4%.

[0014] Preferably, for the step of stirring and reacting the mixed system in the present invention, centrifuging to remove free citric acid and drying to obtain the carrier after the reaction ends is specifically as follows: Place the mixed system in a constant temperature water bath, control the temperature at 60°C ± 0.5°C, stir at a speed of 300 - 400 r / min for 30 minutes, and maintain the pH value of the reaction system at 4.5 ± 0.2 by dropping a 0.1 mol / L sodium hydroxide solution during this period. After the reaction ends, centrifuge the mixture at 6000 r / min for 15 minutes, discard the supernatant, and wash the precipitate 3 - 5 times with deionized water until the pH value of the washing liquid is 6.5 ± 0.3. Dry the washed precipitate in a vacuum drying oven at 50°C ± 2°C until the moisture content is ≤3% to obtain a carrier with an esterification degree of 1 - 5%.

[0015] Preferably, microcapsule preparation is further included in step (5) of the present invention. Dissolve sodium alginate and chitosan in deionized water in a mass ratio of 3:1, and prepare inner microcapsules with a particle size of 50 - 80 μm by electrostatic spraying. Fill the embedded particles into the inner microcapsules at a filling rate of 70 - 80% of the microcapsule volume; Spray the β - cyclodextrin - potato starch nanoparticle composite film solution on the outer layer and dry it at 40°C ± 2°C until the moisture content ≤ 5% to form an outer film with a thickness of 2 - 5 μm, obtaining the microcapsules.

[0016] Preferably, the microcapsules of the present invention further include Lactobacillus plantarum. Specifically, it further includes: mixing the embedded particles with Lactobacillus plantarum in a mass ratio of 1:0.2, filling them into the inner microcapsules at a filling rate of 70 - 80% of the microcapsule volume.

[0017] Preferably, the β - cyclodextrin - potato starch nanoparticle composite film solution of the present invention is obtained through the following steps: Mix β - cyclodextrin and potato starch nanoparticles in a mass ratio of 1:1 - 2, add deionized water, and control the solid content in the mixed solution to be 8% ± 0.5%; Heat the mixed solution to 60°C ± 2°C and stir it at a speed of 500 - 600 r / min for 30 - 40 minutes until it is completely dissolved; During the stirring process, add 0.05 mol / L sodium citrate solution to the mixed solution to adjust the pH value to 6.8 ± 0.2; Transfer the mixed solution to an ultrasonic disperser and process it at a frequency of 40 kHz and a power of 100 W for 10 - 15 minutes to eliminate particle agglomeration; Filter the dispersed composite film solution through a 0.45 μm microporous membrane and let it stand for defoaming at 25°C ± 1°C for 20 - 30 minutes to obtain the β - cyclodextrin - potato starch nanoparticle composite film solution.

[0018] Preferably, the step (6) of the present invention further includes microcapsule jelly particles. The preparation steps of the microcapsule jelly particles are as follows: Mix the microcapsules and the natural composite colloid solution in a mass ratio of 1:5. The preparation method of the natural composite colloid solution is: using deionized water as a solvent, adding κ - carrageenan, konjac glucomannan, and corn straw aqueous extract. The addition amount of κ - carrageenan is 0.8% of the solvent mass, the addition amount of konjac glucomannan is 0.3% of the solvent mass, and the addition amount of corn straw aqueous extract is 10% of the solvent mass; Stir the mixed solution at 75°C ± 2°C until it is completely dissolved; Inject the mixed solution into a mold and cool it at 25°C ± 1°C for 30 - 40 minutes to form a gel block; Cut the gel block into cubic particles with a particle size of 2 - 3 mm to obtain the microcapsule jelly particles containing microcapsules.

[0019] Preferably, the mixed and formulated beverage of the present invention comprises 300 mg / mL of microencapsulated jelly particles, 300 mg / mL of water extract of corn straw, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, 0.28 mg / mL of potassium sorbate, and the balance is purified water; Stir slowly at 50 - 80 r / min for 1 - 2 minutes at 40°C ± 2°C to form a mixed solution.

[0020] Preferably, the application of the water extract of corn straw obtained according to the preparation method of the present invention for preparing a hypolipidemic drug or a functional beverage.

[0021] The present invention has at least the following beneficial effects: By optimizing the extraction process (material - liquid ratio 1:14, extracting 3 times at 100°C) and formula design (preserving with potassium sorbate), the yield of flavonoid extract and the stability of the beverage are significantly improved, while retaining the herbal fragrance, providing a basis for subsequent functional improvement.

[0022] By precisely controlling the addition amount of citric acid (5% - 8%), pH (4.5 ± 0.2) and temperature (60°C ± 0.5°C), over - esterification is inhibited, the esterification degree of the carrier is stabilized at 1% - 5%, and the deviation of the embedding efficiency is ≤1.2%, significantly improving the process repeatability.

[0023] The microcapsules are filled with Lactobacillus plantarum (mass ratio 1:0.2), and the viable count remains 8.5×10 7 CFU / mL after 6 months of storage (Experiment 3), doubling the hypolipidemic effect.

[0024] The water - holding rate of the compound gel of κ - carrageenan and konjac gum is increased to 85%, the taste score of the jelly particles with a "crispy outside and soft inside" texture is 4.7 points (Experiment 3), and the release of the microcapsules is delayed by 50%, prolonging the time of the hypolipidemic effect.

[0025] The microencapsulated jelly particles in the mixed solution are evenly distributed (particle size 2 - 3 mm), the herbal flavor is integrated with the fragrance of the colloid, the sensory score is 4.6 points, and the consumer acceptance is increased by 30%.

[0026] The present invention, through the design of microencapsulated jelly particles and the compound embedding technology, systematically solves the core problems such as the degradation of active ingredients, the inactivation of probiotics and the poor sensory quality in the development of corn straw beverages.

[0027] Through animal experiments, it is verified that the active ingredients in the water extract of corn straw in the beverage significantly reduce the levels of serum lipids TC, TG, and LDL in hyperlipidemic model rats (P < 0.01 or P < 0.05), and significantly increase the level of HDL (P < 0.01 or P < 0.05) (Experiment 2). The efficacy is close to that of simvastatin, and it has the potential to be developed into a hypolipidemic drug.

[0028] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0029] Figure 1 Collect orbital blood of rats in each group at 2 weeks and 4 weeks to detect the contents of serum TC and TG; Figure 2 Detect the changes in serum blood lipid contents of rats in each group after gavage; Figure 3 For the changes in the body weight of rats during gavage; Figure 4 For the differences in liver mass and body fat content of rats in each group; Figure 5 For the comparison of the changes in fat contents in three parts of rats in each group; Figure 6 For the effects of each administration group on the levels of two liver enzymes, GPT and GOT, in the liver; Figure 7 For the blind test site of the professional sensory panel. Detailed Embodiments

[0030] The following further describes the present invention in detail with reference to embodiments, so that those skilled in the art can implement it according to the description in the specification.

[0031] It should be noted that the experimental methods described in the following implementation schemes are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "setting" should be understood in a broad sense. For example, it can be fixedly connected and set, or detachably connected and set, or integrally connected and set. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. The orientation or positional relationship indicated by the terms "horizontal", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0032] The present invention provides a preparation method of a corn straw beverage, including the following steps: Step (1): Wash the corn straw, dry it, and crush it; Step (2): Add purified water at a material-liquid ratio of 1:12 - 16, soak for 12 - 15 hours to obtain a corn straw mixture solution; Step (3): Extract the corn straw mixture solution under a water bath condition of 80 - 100 °C, extract for 1 - 2 hours each time, repeat the extraction 1 - 3 times, and combine the extraction solutions; Step (4): Coarsely filter the combined extraction solution, and then centrifuge to obtain the supernatant; Step (5): Concentrate the supernatant to obtain a water extract of corn straw; Step (6): The mixed and formulated beverage includes 78 - 700 mg / mL of water extract of corn straw, 0.30 - 0.40 mg / mL of sucralose, 0.32 - 0.40 mg / mL of citric acid, 0.20 - 0.28 mg / mL of potassium sorbate, and the balance is purified water. Mix evenly; Step (7): Sterilize and fill the mixed solution to obtain the finished beverage.

[0033] Example 1 Preparation method of corn straw beverage: Step (1): Wash the corn straw and dry it, then crush it to a particle size of ≤5 mm; Crushing equipment: A hammer mill (such as SFSP-60 type) can be selected, equipped with a 5 mm sieve; Assembly position: The outlet of the crusher is connected to a vibrating screening device to ensure that the particle size meets the standard.

[0034] Step (2): Add purified water at a material-liquid ratio of 1:14, soak for 12 hours to obtain a corn straw mixture solution; Step (3): Place the corn straw mixture solution in a reflux device, extract it under a water bath condition of 100 °C, extract for 1 hour each time, repeat the extraction 3 times, and combine the extraction solutions; Material-liquid ratio: 1:14 (the optimal combination of the orthogonal experiment is 14 times the amount of added water); Extraction temperature and times: Extract 3 times at 100 °C in a water bath, 1 hour each time (optimal parameters of the orthogonal experiment); Equipment selection: A SHZ-D type condensing reflux device can be selected, equipped with a constant temperature water bath (temperature control accuracy ±1 °C); Assembly position: The extraction solution is transferred to a storage tank through a siphon tube, and the 3 extraction solutions are combined.

[0035] Step (4): Coarsely filter the combined extraction solution with a filter cloth, then centrifuge at 3000 r / min for 10 minutes, and take the supernatant; Step (5): Concentrate the supernatant to 1 / 3 of the original volume of the extraction solution to obtain a water extract of corn straw; Centrifugation parameters: Centrifuge at 3000 r / min for 10 minutes; Centrifugation equipment: A TD5A type low-speed centrifuge can be selected; Concentration end point: Concentrate to 1 / 3 of the original volume (with an error of ±3%), achieved by a rotary evaporator (such as RE-52AA type).

[0036] Step (6) The mixed beverage formulation includes 700 mg / mL of corn straw aqueous extract, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, 0.28 mg / mL of potassium sorbate, and the balance is purified water, and mix evenly; Component ratio: Corn straw aqueous extract: 700 mg / mL; Sucralose: 0.40 mg / mL; Citric acid: 0.36 mg / mL; Potassium sorbate: 0.28 mg / mL; The balance is purified water.

[0037] Step (7) Sterilize the mixed solution with ultraviolet light for 15 minutes, and fill it into sterilized glass bottles to obtain the finished beverage.

[0038] Sterilization and filling: For ultraviolet sterilization, a UV-C ultraviolet sterilization system with a wavelength of 253.7 nm can be selected. The ultraviolet sterilization dose is 400 mJ / cm² (refer to the FDA liquid ultraviolet sterilization standard (21 CFR 179.39)), and the flow rate is 0.8 L / min. The equipment flow rate is adjusted according to the beverage viscosity and can be controlled at 0.5 - 1.5 L / min to ensure that the liquid layer thickness ≤ 5 mm to improve the ultraviolet penetration efficiency. The power of the ultraviolet lamp is 30 - 60 W, and the lamp life ≥ 8000 hours. The sterilization device can be installed at the front end of the filling line and connected to the aseptic filling equipment through a sealed pipeline to avoid secondary contamination.

[0039] The mixed solution is transported through a pipeline to the ultraviolet sterilization chamber, and is irradiated by ultraviolet light from multiple angles under turbulent flow conditions. A real-time ultraviolet sensor (such as ILT950UV) monitors the irradiation dose, and automatically adjusts the flow rate or supplements light when it is insufficient. After sterilization, the beverage enters the filling line through an aseptic pipeline. The distance between the filling head and the bottle mouth is controlled at 10 - 15 mm, and the filling accuracy is ±1 mL.

[0040] Experiment 1 I. Process investigation of corn straw extract: Taking the extraction time, the amount of added water, and the number of extraction times as the investigation factors, and taking the total flavonoid content and the extract yield as the indexes (the weighted coefficient of the total flavonoid content is 0.8, and the weighted coefficient of the extract yield is 0.2), select L9(3 4)The experiments were carried out using an orthogonal array, and the factor levels are designed in Table 1. The comprehensive weighted scoring method was adopted. Taking the maximum values of the total flavonoid content and the extract yield in the orthogonal experiments as 100 points, the total amounts of each index component were respectively converted into scoring values, the comprehensive score was calculated, and the results of the orthogonal experiments were calculated based on the comprehensive score as shown in Table 2, and the variance analysis was carried out as shown in Table 3 to optimize the best extraction process of corn straw.

[0041] Table 1 Factor levels of the orthogonal experiment of corn straw Table 2 Results of the orthogonal experiment on the process of corn straw Table 3 Variance analysis of corn straw Note: * indicates significant difference (P < 0.05), ** indicates extremely significant difference (P < 0.01).

[0042] From the results of the orthogonal experiment and the range analysis, it can be seen that A3B1C3 requires adding 16 times the amount of water (higher cost), while A2B1C3 (14 times the amount of water) is more economical on the premise that the loss of active ingredients is controllable. Therefore, the latter is selected; the optimal combination of the three factors is A2B1C3, that is, adding 14 times the amount of water, extracting for 1 h each time, and extracting 3 times. Under this condition, after 3 verification experiments, the total flavonoid content was measured to be 0.007716%, the extract yield was 15.80%, and the comprehensive score was 97.81. In summary, the best extraction process of corn straw is to add 14 times the amount of water, extract for 1 h each time, and extract 3 times.

[0043] Experiment 2 For the optimal combination of A2B1C3, that is, adding 14 times the amount of water, extracting for 1 h each time, and extracting 3 times, and concentrating to 1 / 3 of the original volume, the anti - hyperlipidemic effect of the obtained aqueous extract of corn straw was measured.

[0044] Experimental method: 1. Rats were fed with a high - fat diet to establish a hyperlipidemia model. The feeding method was used for modeling. The nutritional composition of the high - fat diet was the specified high - fat diet formula in "Functional Test and Evaluation Methods (Health Food) (2022 Edition)" (which helps to maintain the healthy level of blood lipids (cholesterol / triglyceride)). Cholesterol 1.2%, lard 15%, sucrose 20%, sodium cholate 0.2%, and basal diet 63.6% (appropriate amounts of casein, calcium hydrogen phosphate, stone powder, etc. are also required. Except for crude fat, the moisture, crude protein, crude fat, crude fiber, crude ash, calcium, and phosphorus of the model diet have reached the national standards for maintenance diets).

[0045] After 48 SPF-grade SD rats were adaptively fed for one week, the rats were divided into 6 groups by random stratified sampling according to the weighing results, namely the blank control group, the model group (HFD), the positive drug control group, the high-dose group of water extract of corn straw (WECS-H) with a concentration of 700 mg / mL, the medium-dose group of water extract of corn straw (WECS-M) with a concentration of 234 mg / mL, and the low-dose group of water extract of corn straw (WECS) with a concentration of 78 mg / mL. The concentrated extract of corn straw was diluted with water into gastric lavage solutions of corresponding concentrations, and the gavage dose was 1 mL / 100 g, once a day for 35 consecutive days (the same for the other groups); the gavage volume of the simvastatin positive drug group was 4 mg / kg of simvastatin suspension, once a day; the blank control group and the HFD group were gavaged with an equal amount of water every day. The food intake and body weight changes were recorded weekly, and blood was taken from the fundus venous plexus at the 2nd and 4th weeks to determine whether the model was established. Before collecting blood samples on the 35th day (the fifth week), all rats were fasted but allowed to drink water, and drugs were administered 12 h later. After the last administration, the rats were anesthetized, and abdominal aortic blood was taken into a blood collection tube. Then, it was centrifuged at 3000 r / min for 10 min, the supernatant was taken, and stored at -80 °C for further testing.

[0046] 2. Records of body weight, body fat characteristics, viscera, and fat mass (the results are shown in Figure 3 , Figure 4 , Figure 5 ) Record the weekly body weight changes during the experiment; record the liver mass after taking out the viscera on the last day of the experiment; record the masses of epididymal fat, perirenal fat, mesenteric fat and their changes among groups, calculate the total body fat and body fat rate and analyze them.

[0047] Total body fat = total epididymal fat + total perirenal fat + total mesenteric fat Body fat rate = total body fat / rat body weight 3. Detection of biochemical indicators One hour after the last administration on the 35th day, the rats were anesthetized, and abdominal aortic blood was taken. It was left standing at room temperature for 10 min, then centrifuged at 4000 r / min at 4 °C for 10 min. Serum was taken with a 0.5 ml centrifuge tube and stored at -80 °C for further testing. At the same time, the required organ samples were taken out and stored separately.

[0048] 4. Detection of lipid indicators in serum Detect the levels of four lipid components in serum - total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C) according to the operations in the instruction manual of the assay kit. The results are shown in Figure 1 , Figure 2 as shown.

[0049] 5. Detection of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) in the liver Take liver tissue samples (stored at -80 °C for later use), precisely cut 30 mg, and add 9-fold volume of absolute ethanol as the homogenization medium according to the ratio of weight (g): volume (ml) = 1:9. Homogenize mechanically under ice-water bath conditions at 2500 r / min for 10 min, and take the supernatant. Detect GOT and GPT in the rat liver according to the operations in the instruction manual of the assay kit. The results are shown in Figure 6 as shown.

[0050] Note: △△: Compared with the blank group, P < 0.01; *: Compared with the model group, P < 0.05; **: Compared with the model group (HFD), P < 0.01.

[0051] Experimental results: The experimental results showed that compared with the model group, a decrease in body fat was observed in the corn straw administration group, and the body weight in the corn straw administration group was significantly reduced in the fifth week (P < 0.01 or P < 0.05); the corn straw administration group could significantly reduce the liver mass (P < 0.01 or P < 0.05), body fat rate (P < 0.01 or P < 0.05), and fat fractions in various parts (P < 0.01 or P < 0.05); the levels of TC, TG, and LDL in the corn straw administration group were significantly reduced (P < 0.01 or P < 0.05), and the level of HDL was significantly increased (P < 0.01 or P < 0.05); the corn straw administration group could significantly reduce the levels of serum lipids TC, TG, and LDL (P < 0.01 or P < 0.05), and significantly increase the level of HDL (P < 0.01 or P < 0.05); the corn straw administration group could significantly reduce the levels of liver transaminases - GOT and GPT (P < 0.01 or P < 0.05); The water extract of corn straw can improve the body weight and body fat of hyperlipidemic rats, and can reduce blood lipid levels. At the same time, it plays a role in protecting the liver, improving the blood lipid level of the liver, significantly reducing the level of liver transaminase, alleviating liver injury, and inhibiting fatty degeneration of the liver. Its effect is comparable to that of simvastatin, suggesting its potential as a natural lipid-lowering drug, and the functional intensity can be changed by adjusting the different concentrations of active ingredients.

[0052] Example 2 The preparation method of the corn straw beverage is the same as steps (1) to (4) and step (7) of Example 1, except that step (5) includes preparing microcapsule jelly particles, and step (6) includes 300 mg / mL of microcapsule jelly particles and 300 mg / mL of the water extract of corn straw. Specifically: Step (1) Wash the corn straw and dry it, and crush it to a particle size of ≤5 mm; Step (2) Add pure water according to a material-liquid ratio of 1:14 and soak for 12 hours to obtain a corn straw mixture; Step (3) Place the corn straw mixture in a reflux device and extract it under a water bath condition of 100 °C for 1 hour each time, repeat the extraction 3 times, and combine the extracts; Step (4) Coarsely filter the combined extract with a filter cloth, and then centrifuge it at 3000 r / min for 10 minutes to obtain the supernatant; Step (5) Concentrate the supernatant to 1 / 3 of the original extract volume to obtain the water extract of corn straw; Then the steps for preparing the carrier are: Mix potato starch nanoparticles (particle size 50 nm to 100 nm) and β-cyclodextrin in a mass ratio of 1:1 - 1.5 to obtain a first mixture. Add a citric acid solution with a mass concentration of 3% to the first mixture, and the addition amount of the citric acid solution is 5 - 8% of the total mass of the first mixture. Place the mixed system in a constant temperature water bath, control the temperature at 60 °C ± 0.5 °C, stir at a speed of 300 - 400 r / min for 30 minutes, and maintain the pH value of the reaction system at 4.5 ± 0.2 by dropping 0.1 mol / L sodium hydroxide solution during this period; After the reaction is completed, centrifuge the mixture at 6000 r / min for 15 minutes, discard the supernatant, wash the precipitate with deionized water 3 - 5 times until the pH value of the washing solution is 6.5 ± 0.3; Dry the washed precipitate in a vacuum drying oven at 50 °C ± 2 °C until the moisture content is ≤3% to obtain a carrier with an esterification degree of 1 - 5%; Mix a portion of the aqueous extract of corn straw with the carrier at a volume-mass ratio of 4 ml:1 g, and treat it for 20 minutes at an ultrasonic frequency of 45 kHz and a power of 150 W to embed the flavonoids in the aqueous extract of corn straw into the pores with an embedding rate ≥ 90%; then prepare embedded particles with a particle size of 10 - 30 μm by spray drying, and control the moisture content ≤ 4%; among them, the preparation of the carrier and the embedded particles: Potato starch nanoparticles can be purchased from food additive suppliers (such as Sigma-Aldrich) with a particle size range of 50 - 100 nm. When mixing β-cyclodextrin with starch, use an electronic balance (accuracy 0.01 g) to weigh it at a ratio of 1:1.25. Control the temperature of the constant temperature water bath (such as HH-4 digital display constant temperature water bath) at 60°C ± 0.5°C and the stirring paddle speed at 350 r / min. Adjust the pH by dropping 0.1 mol / L sodium hydroxide solution (analytical pure) through a peristaltic pump (BT100-1F type), and monitor it in real time with a pH meter (PHS-3C type). Wash the centrifuged carrier with deionized water until the pH is 6.5 ± 0.3, set the temperature of the vacuum drying oven (DZF-6020 type) at 50°C ± 2°C, and the drying time is about 6 hours.

[0053] Then, microcapsules were prepared as follows: Sodium alginate and chitosan were dissolved in deionized water at a mass ratio of 3:1, and inner microcapsules with a particle size of 50 - 80 μm were prepared by electrospraying method. The embedded particles were filled into the inner microcapsules with a filling rate of 70 - 80% of the microcapsule volume. A β-cyclodextrin - potato starch nanoparticle composite film solution was sprayed on the outer layer and dried at 40°C ± 2°C until the moisture content was ≤ 5% to form an outer film with a thickness of 2 - 5 μm, obtaining the microcapsules. The β-cyclodextrin - potato starch nanoparticle composite film solution was obtained through the following steps: β-cyclodextrin and potato starch nanoparticles were mixed at a mass ratio of 1:1 - 2, deionized water was added, and the solid content in the mixed solution was controlled to be 8% ± 0.5%. The mixed solution was heated to 60°C ± 2°C and stirred at a speed of 500 - 600 r / min for 30 - 40 minutes until completely dissolved. During the stirring process, a 0.05 mol / L sodium citrate solution was added dropwise to the mixed solution to adjust the pH value to 6.8 ± 0.2. The mixed solution was transferred to an ultrasonic disperser and treated at a frequency of 40 kHz and a power of 100 W for 10 - 15 minutes to eliminate particle agglomeration. The dispersed composite film solution was filtered through a 0.45 μm microporous membrane and left to stand for defoaming at 25°C ± 1°C for 20 - 30 minutes to obtain the β-cyclodextrin - potato starch nanoparticle composite film solution. Among them, sodium alginate (food grade, viscosity 200 - 400 mPa•s) and chitosan (degree of deacetylation ≥ 85%) were dissolved in deionized water at a ratio of 3:1, and inner microcapsules with a particle size of 50 - 80 μm were prepared by an electrospraying device (nozzle diameter 0.5 mm, voltage 15 kV, receiving distance 10 cm, solution flow rate 0.5 mL / h). Spray drying was carried out using a Yamato ADL310 type centrifugal spray drying tower with an inlet air temperature of 90°C and an outlet air temperature of 50°C. In the composite film solution, β-cyclodextrin and starch nanoparticles were mixed at a ratio of 1:1.5, and the solid content of 8% ± 0.5% was calibrated by a refractometer (such as PAL-1).

[0054] Then the steps for preparing the microcapsule jelly particles are as follows: Mix the microcapsules and the natural composite colloid solution at a mass ratio of 1:5 to obtain a mixed solution. The preparation method of the natural composite colloid solution is as follows: Using deionized water as the solvent, add κ-carrageenan, konjac glucomannan, and the water extract of corn straw. The addition amount of κ-carrageenan is 0.8% of the mass of the solvent, the addition amount of konjac glucomannan is 0.3% of the mass of the solvent, and the addition amount of the water extract of corn straw is 10% of the mass of the solvent; Stir the mixed solution at 75°C ± 2°C until it is completely dissolved; Inject the mixed solution into a mold and cool and solidify it at 25°C ± 1°C for 30 - 40 minutes to form a gel block; Cut the gel block into cubic particles with a particle size of 2 - 3 mm to obtain microcapsule jelly particles containing microcapsules. Among them, the gel mixed solution is injected into a polytetrafluoroethylene mold (20 cm × 20 cm × 1 cm), the temperature of the cooling table is 25°C ± 1°C, and the gel is cut using a multi-functional dicing machine (QD-200 type) with a blade spacing of 2.5 mm.

[0055] Step (6) The mixed and formulated beverage includes 300 mg / mL of microcapsule jelly particles, 300 mg / mL of the water extract of corn straw, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, 0.28 mg / mL of potassium sorbate, and the balance is purified water; Stir slowly at 40°C ± 2°C at 50 - 80 r / min for 1 - 2 minutes to form a mixed solution.

[0056] Step (7) Sterilize the mixed solution by ultraviolet light for 15 minutes and fill it into sterilized glass bottles to obtain the finished beverage.

[0057] Example 3 The preparation method of the corn straw beverage is basically the same as that of Example 2, except that the microcapsules in step (5) also include Lactobacillus plantarum. Specifically: Step (1) Wash the corn straw and dry it, and crush it to a particle size of ≤5 mm; Step (2) Add purified water at a material-liquid ratio of 1:14 and soak for 12 hours to obtain a corn straw mixed solution; Step (3) Place the corn straw mixed solution in a reflux device and extract it under a water bath condition of 100°C. Each extraction is for 1 hour, and the extraction is repeated 3 times, and the extraction solutions are combined; Step (4) Coarsely filter the combined extraction solution with a filter cloth, and then centrifuge it at 3000 r / min for 10 minutes to take the supernatant; Step (5) Concentrate the supernatant to 1 / 3 of the volume of the original extraction solution to obtain the water extract of corn straw; Then the steps for preparing the carrier are as follows: Mix potato starch nanoparticles (with a particle size of 50 nm to 100 nm) and β-cyclodextrin in a mass ratio of 1:1 - 1.5 to obtain a first mixture. Add a citric acid solution with a mass concentration of 3% to the first mixture, and the addition amount of the citric acid solution is 5 - 8% of the total mass of the first mixture. Place the mixed system in a constant temperature water bath, control the temperature at 60°C ± 0.5°C, stir at a speed of 300 - 400 r / min for 30 minutes, and during this period, maintain the pH value of the reaction system at 4.5 ± 0.2 by dropwise adding a 0.1 mol / L sodium hydroxide solution; after the reaction is completed, centrifuge the mixture at 6000 r / min for 15 minutes, discard the supernatant, and wash the precipitate with deionized water 3 - 5 times until the pH value of the washing solution is 6.5 ± 0.3; dry the washed precipitate in a vacuum drying oven at 50°C ± 2°C until the moisture content ≤ 3% to obtain a carrier with an esterification degree of 1 - 5%; Mix a part of the water extract of corn straw with the carrier at a volume-to-mass ratio of 4 ml:1 g, and treat it at an ultrasonic frequency of 45 kHz and a power of 150 W for 20 minutes to embed the flavonoids in the water extract of corn straw into the pores, with an embedding rate ≥ 90%; then prepare embedded particles with a particle size of 10 - 30 μm by spray drying, and control the moisture content ≤ 4%; among them, for the preparation of the carrier and the embedded particles: Potato starch nanoparticles can be purchased from food additive suppliers (such as Sigma-Aldrich), with a particle size range of 50 - 100 nm. When mixing β-cyclodextrin and starch, use an electronic balance (with a precision of 0.01 g) to weigh according to a ratio of 1:1.25. The temperature of the constant temperature water bath (such as HH-4 digital display constant temperature water bath) is controlled at 60°C ± 0.5°C, and the rotation speed of the stirring paddle is 350 r / min. The pH is adjusted by dropwise adding a 0.1 mol / L sodium hydroxide solution (analytical pure) through a peristaltic pump (BT100-1F type), and the pH meter (PHS-3C type) monitors in real time. The centrifuged carrier is washed with deionized water until the pH is 6.5 ± 0.3, and the temperature of the vacuum drying oven (DZF-6020 type) is set at 50°C ± 2°C, and the drying time is about 6 hours.

[0058] Then, microcapsules were prepared as follows: Sodium alginate and chitosan were dissolved in deionized water at a mass ratio of 3:1, and inner microcapsules with a particle size of 50 - 80 μm were prepared by electrospraying method. The encapsulated particles were mixed with Lactobacillus plantarum at a mass ratio of 1:0.2 and filled into the inner microcapsules with a filling rate of 70 - 80% of the microcapsule volume. A β-cyclodextrin - potato starch nanoparticle composite film solution was sprayed on the outer layer and dried at 40°C ± 2°C until the moisture content was ≤ 5% to form an outer film with a thickness of 2 - 5 μm, obtaining the microcapsules. The β-cyclodextrin - potato starch nanoparticle composite film solution was obtained through the following steps: β-cyclodextrin and potato starch nanoparticles were mixed at a mass ratio of 1:1 - 2, deionized water was added, and the solid content in the mixed solution was controlled at 8% ± 0.5%. The mixed solution was heated to 60°C ± 2°C and stirred at a speed of 500 - 600 r / min for 30 - 40 minutes until completely dissolved. During the stirring process, a 0.05 mol / L sodium citrate solution was added dropwise to the mixed solution to adjust the pH value to 6.8 ± 0.2. The mixed solution was transferred to an ultrasonic disperser and treated at a frequency of 40 kHz and a power of 100 W for 10 - 15 minutes to eliminate particle agglomeration. The dispersed composite film solution was filtered through a 0.45 μm microporous membrane and left to stand for defoaming at 25°C ± 1°C for 20 - 30 minutes to obtain the β-cyclodextrin - potato starch nanoparticle composite film solution. Among them, sodium alginate (food grade, viscosity 200 - 400 mPa•s) and chitosan (degree of deacetylation ≥ 85%) were dissolved in deionized water at a ratio of 3:1, and inner microcapsules with a particle size of 50 - 80 μm were prepared using an electrospray device (nozzle diameter 0.5 mm, voltage 15 kV, receiving distance 10 cm, solution flow rate 0.5 mL / h). Spray drying was carried out using a Yamato ADL310 type centrifugal spray drying tower with an inlet air temperature of 90°C and an outlet air temperature of 50°C. In the composite film solution, β-cyclodextrin and starch nanoparticles were mixed at a ratio of 1:1.5, and the solid content of 8% ± 0.5% was calibrated using a refractometer (such as PAL-1).

[0059] Then the steps for preparing the microcapsule jelly particles are as follows: Mix the microcapsules with the natural composite colloid solution at a mass ratio of 1:5 to obtain a mixed solution. The preparation method of the natural composite colloid solution is as follows: Using deionized water as the solvent, add κ-carrageenan, konjac glucomannan, and the water extract of corn straw. The addition amount of κ-carrageenan is 0.8% of the solvent mass, the addition amount of konjac glucomannan is 0.3% of the solvent mass, and the addition amount of the water extract of corn straw is 10% of the solvent mass; Stir the mixed solution at 75°C ± 2°C until it is completely dissolved; Inject the mixed solution into a mold and cool and solidify it at 25°C ± 1°C for 30 - 40 minutes to form a gel block; Cut the gel block into cubic particles with a particle size of 2 - 3 mm to obtain the microcapsule jelly particles containing microcapsules. Among them, the gel mixed solution is injected into a polytetrafluoroethylene mold (20 cm × 20 cm × 1 cm), the temperature of the cooling table is 25°C ± 1°C, and the gel is cut using a multifunctional dicing machine (QD - 200 type) with a blade spacing of 2.5 mm.

[0060] Step (6) The mixed and formulated beverage includes 300 mg / mL of microcapsule jelly particles, 300 mg / mL of the water extract of corn straw, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, 0.28 mg / mL of potassium sorbate, and the balance is purified water; Slowly stir at 40°C ± 2°C at 50 - 80 r / min for 1 - 2 minutes to form a mixed solution.

[0061] Step (7) Sterilize the mixed solution by ultraviolet light for 15 minutes and fill it into sterilized glass bottles to obtain the finished beverage.

[0062] Example 4 The preparation method of the corn straw beverage is basically the same as that of Example 2, except that in step (5), microcapsule jelly particles are not prepared, only microcapsules are prepared, and step (6) includes 300 mg / mL of microcapsules and 300 mg / mL of the water extract of corn straw. Specifically: Step (1) Wash the corn straw, dry it, and crush it to a particle size of ≤5 mm; Step (2) Add purified water according to a solid - liquid ratio of 1:14 and soak for 12 hours to obtain a corn straw mixed solution; Step (3) Place the corn straw mixed solution in a reflux device and extract it under a water bath condition of 100°C. Each extraction is for 1 hour, and the extraction is repeated 3 times, and the extraction liquids are combined; Step (4) Coarsely filter the combined extraction liquid with a filter cloth, and then centrifuge it at 3000 r / min for 10 minutes to take the supernatant; Step (5) Concentrate the supernatant to 1 / 3 of the original extraction liquid volume to obtain the water extract of corn straw; Then the steps for preparing the carrier are as follows: Mix potato starch nanoparticles (with a particle size of 50 nm to 100 nm) and β-cyclodextrin in a mass ratio of 1:1 - 1.5 to obtain a first mixture. Add a citric acid solution with a mass concentration of 3% to the first mixture, and the addition amount of the citric acid solution is 5 - 8% of the total mass of the first mixture. Place the mixed system in a constant temperature water bath, control the temperature at 60°C ± 0.5°C, stir at a speed of 300 - 400 r / min for 30 minutes, and during this period, maintain the pH value of the reaction system at 4.5 ± 0.2 by dropwise adding a 0.1 mol / L sodium hydroxide solution; after the reaction is completed, centrifuge the mixture at 6000 r / min for 15 minutes, discard the supernatant, and wash the precipitate with deionized water 3 - 5 times until the pH value of the washing solution is 6.5 ± 0.3; dry the washed precipitate in a vacuum drying oven at 50°C ± 2°C until the water content ≤ 3% to obtain a carrier with an esterification degree of 1 - 5%; Mix a part of the water extract of corn straw with the carrier at a volume-to-mass ratio of 4 ml:1 g, and treat it at an ultrasonic frequency of 45 kHz and a power of 150 W for 20 minutes to embed the flavonoids in the water extract of corn straw into the pores, with an embedding rate ≥ 90%; then prepare embedded particles with a particle size of 10 - 30 μm by spray drying, and control the water content ≤ 4%; among them, for the preparation of the carrier and the embedded particles: Potato starch nanoparticles can be purchased from food additive suppliers (such as Sigma - Aldrich), with a particle size range of 50 - 100 nm. When mixing β-cyclodextrin and starch, use an electronic balance (with a precision of 0.01 g) to weigh according to a ratio of 1:1.25. The temperature of the constant temperature water bath (such as HH - 4 digital display constant temperature water bath) is controlled at 60°C ± 0.5°C, and the rotation speed of the stirring paddle is 350 r / min. The pH is adjusted by dropwise adding a 0.1 mol / L sodium hydroxide solution (analytical pure) through a peristaltic pump (BT100 - 1F type), and the pH meter (PHS - 3C type) monitors in real time. The centrifuged carrier is washed with deionized water until the pH is 6.5 ± 0.3, and the temperature of the vacuum drying oven (DZF - 6020 type) is set at 50°C ± 2°C, and the drying time is about 6 hours.

[0063] Then, microcapsules were prepared: Sodium alginate and chitosan were dissolved in deionized water at a mass ratio of 3:1, and inner microcapsules with a particle size of 50 - 80 μm were prepared by electrospray method; the embedded particles were filled into the inner microcapsules, and the filling rate was 70 - 80% of the microcapsule volume; a β-cyclodextrin - potato starch nanoparticle composite film solution was sprayed on the outer layer and dried at 40°C ± 2°C until the moisture content was ≤ 5% to form an outer film with a thickness of 2 - 5 μm, obtaining the microcapsules. Among them, the β-cyclodextrin - potato starch nanoparticle composite film solution was obtained through the following steps: β-cyclodextrin and potato starch nanoparticles were mixed at a mass ratio of 1:1 - 2, deionized water was added, and the solid content in the mixed solution was controlled to be 8% ± 0.5%; the mixed solution was heated to 60°C ± 2°C and stirred at a speed of 500 - 600 r / min for 30 - 40 minutes until completely dissolved; during the stirring process, a 0.05 mol / L sodium citrate solution was added dropwise to the mixed solution to adjust the pH value to 6.8 ± 0.2; the mixed solution was transferred to an ultrasonic disperser and treated at a frequency of 40 kHz and a power of 100 W for 10 - 15 minutes to eliminate particle aggregation; the dispersed composite film solution was filtered through a 0.45 μm microporous membrane and left to stand for defoaming at 25°C ± 1°C for 20 - 30 minutes to obtain the β-cyclodextrin - potato starch nanoparticle composite film solution. Among them, sodium alginate (food grade, viscosity 200 - 400 mPa•s) and chitosan (degree of deacetylation ≥ 85%) were dissolved in deionized water at a ratio of 3:1, and inner microcapsules with a particle size of 50 - 80 μm were prepared by an electrospray device (nozzle diameter 0.5 mm, voltage 15 kV, receiving distance 10 cm, solution flow rate 0.5 mL / h). Spray drying was carried out using a Yamato ADL310 type centrifugal spray drying tower, with an inlet air temperature of 90°C and an outlet air temperature of 50°C. In the composite film solution, β-cyclodextrin and starch nanoparticles were mixed at a ratio of 1:1.5, and the solid content of 8% ± 0.5% was calibrated by a refractometer (such as PAL-1).

[0064] Step (6) The mixed and formulated beverage includes 300 mg / mL of microcapsules, 300 mg / mL of aqueous extract of corn straw, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, 0.28 mg / mL of potassium sorbate, and the balance is purified water; it was slowly stirred at 50 - 80 r / min at 40°C ± 2°C for 1 - 2 minutes to form a mixed solution.

[0065] Step (7) The mixed solution was sterilized by ultraviolet light for 15 minutes and filled into sterilized glass bottles to obtain the finished beverage.

[0066] Example 5 The preparation method of the corn straw beverage is basically the same as that of Example 2, except that in step (5), microcapsules and microcapsule jelly particles are not prepared, only embedding particles are prepared, and step (6) includes 300 mg / mL of embedding particles and 300 mg / mL of corn straw aqueous extract. Specifically: In step (1), the corn straw is washed and dried, and then crushed to a particle size of ≤5 mm; In step (2), pure water is added according to a solid-liquid ratio of 1:14, and the mixture is soaked for 12 hours to obtain a corn straw mixture; In step (3), the corn straw mixture is placed in a reflux device and extracted under a water bath condition of 100°C for 1 hour each time, and the extraction is repeated 3 times, and the extracts are combined; In step (4), the combined extract is roughly filtered with a filter cloth, and then centrifuged at 3000 r / min for 10 minutes, and the supernatant is taken; In step (5), the supernatant is concentrated to 1 / 3 of the volume of the original extract to obtain a corn straw aqueous extract; Then the steps for preparing the carrier are as follows: Potato starch nanoparticles (with a particle size of 50 nm to 100 nm) and β-cyclodextrin are mixed in a mass ratio of 1:1 - 1.5 to obtain a first mixture. A citric acid solution with a mass concentration of 3% is added to the first mixture, and the addition amount of the citric acid solution is 5 - 8% of the total mass of the first mixture. The mixed system is placed in a constant temperature water bath, and the temperature is controlled at 60°C ± 0.5°C, and stirred at a speed of 300 - 400 r / min for 30 minutes. During this period, the pH value of the reaction system is maintained at 4.5 ± 0.2 by dropping 0.1 mol / L sodium hydroxide solution; after the reaction is completed, the mixture is centrifuged at 6000 r / min for 15 minutes, the supernatant is discarded, and the precipitate is washed 3 - 5 times with deionized water until the pH value of the washing solution is 6.5 ± 0.3; the washed precipitate is dried in a vacuum drying oven at 50°C ± 2°C until the water content is ≤3% to obtain a carrier with an esterification degree of 1 - 5%; Mix a portion of the aqueous extract of corn straw with the carrier at a volume-to-mass ratio of 4 mL:1 g, and treat it at an ultrasonic frequency of 45 kHz and a power of 150 W for 20 minutes to embed the flavonoids in the aqueous extract of corn straw into the pores with an embedding rate ≥ 90%; then prepare embedded particles with a particle size of 10 - 30 μm by spray drying, and control the moisture content ≤ 4%; among them, the preparation of the carrier and the embedded particles: Potato starch nanoparticles can be purchased from food additive suppliers (such as Sigma - Aldrich) with a particle size range of 50 - 100 nm. When mixing β - cyclodextrin and starch, use an electronic balance (accuracy 0.01 g) to weigh according to a ratio of 1:1.25. Control the temperature of the constant temperature water bath (such as HH - 4 digital display constant temperature water bath) at 60°C ± 0.5°C and the stirring paddle speed at 350 r / min. Adjust the pH by dropping 0.1 mol / L sodium hydroxide solution (analytical pure) through a peristaltic pump (BT100 - 1F type), and monitor it in real - time with a pH meter (PHS - 3C type). Wash the centrifuged carrier with deionized water until the pH is 6.5 ± 0.3, set the temperature of the vacuum drying oven (DZF - 6020 type) at 50°C ± 2°C, and the drying time is about 6 hours.

[0067] Step (6) The mixed - formulated beverage includes 300 mg / mL of embedded particles, 300 mg / mL of the aqueous extract of corn straw, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, 0.28 mg / mL of potassium sorbate, and the balance is purified water; slowly stir at 50 - 80 r / min for 1 - 2 minutes at 40°C ± 2°C to form a mixed solution.

[0068] Step (7) Sterilize the mixed solution with ultraviolet light for 15 minutes and fill it into sterilized glass bottles to obtain the finished beverage.

[0069] Among them, the degree of esterification can be verified by titration method, and the operation steps are as follows: Reagents: 0.1 mol / L sodium hydroxide (NaOH) standard solution, 0.1 mol / L hydrochloric acid (HCl) standard solution, Phenolphthalein indicator (1% ethanol solution); Steps: Accurately weigh 1.000 g of the dried carrier sample, dissolve it in 50 mL of deionized water, heat to 60°C and stir to dissolve; add an excessive amount of 0.1 mol / L NaOH solution (such as 10 mL), saponify at 80°C in a water bath for 30 minutes to hydrolyze the ester bond to form carboxylate. After cooling, titrate the excessive NaOH with 0.1 mol / L HCl standard solution, and the end point is when the phenolphthalein indicator changes from pink to colorless. At the same time, conduct a blank test (without adding the sample). Calculate: ; V blank : The volume of HCl consumed in the blank test (mL); V sample : Volume of HCl consumed in sample test (mL); C HCl : Concentration of HCl solution (mol / L); M 酯基 : Molar mass of ester group; m sample : Mass of sample (g); n 总羟基 : Total molar number of esterifiable hydroxyl groups in the sample.

[0070] Experiment 3: Comparison of quality stability during storage of finished beverage I. Experimental design and method Sample preparation: Prepare the finished beverage according to the methods of Examples 1 - 5, and dispense it into sterilized glass bottles and seal for storage.

[0071] Storage conditions: Normal temperature (25°C ± 2°C), protected from light, and the storage times are 0 days (initial), 3 months, and 6 months respectively.

[0072] Test indicators and methods: Sensory evaluation: Color: Visually observe the color change of the beverage (0 - 5 points, 5 being the best).

[0073] Odor: Whether the herbal fragrance is retained and whether there is any abnormal odor (0 - 5 points).

[0074] Flavor: Crispness of jelly particles, balance of sour and sweet, and roughness (0 - 5 points).

[0075] Evaluation method: The average value is taken from the blind test of a 10 - person professional sensory panel. The blind test site is as Figure 7 shown.

[0076] Microbiological detection: Activity of Lactobacillus plantarum (only in Example 3): Take 1 mL of the sample and dilute it serially to 10⁻ 6 , spread it on MRS agar medium (Oxoid CM0361), and incubate anaerobically at 37°C for 48 hours, then count the viable cell number (CFU / mL).

[0077] Spoilage flora (total colony count, mold, yeast): Detect according to the GB4789.2 - 2016 standard.

[0078] Determination of flavonoid content: Use the Agilent 1260 HPLC system, with rutin as the standard. The chromatographic conditions are a C18 column (4.6×250 mm, 5 μm), mobile phase acetonitrile - 0.1% phosphoric acid water (20:80, v / v), flow rate 1.0 mL / min, detection wavelength 280 nm, and calculate the retention rate.

[0079] II. Experimental Results 1. Sensory Evaluation Data Example 1: Day 0: Color score: 4.2, Odor score: 4.0, Flavor score: 3.8.

[0080] 3 months: Color score: 3.5, Odor score: 3.2, Flavor score: 2.9.

[0081] 6 months: Color score: 2.8, Odor score: 2.5, Flavor score: 2.0.

[0082] Jelly texture: No jelly granule design, not scored.

[0083] Example 2: Day 0: Color score: 4.8, Odor score: 4.7, Flavor score: 4.5, Jelly texture score: 4.6.

[0084] 3 months: Color score: 4.5, Odor score: 4.3, Flavor score: 4.2, Jelly texture score: 4.3.

[0085] 6 months: Color score: 4.0, Odor score: 3.9, Flavor score: 3.8, Jelly texture score: 3.9.

[0086] Example 3: Day 0: Color score: 4.8, Odor score: 4.7, Flavor score: 4.6, Jelly texture score: 4.7.

[0087] 3 months: Color score: 4.6, Odor score: 4.5, Flavor score: 4.4, Jelly texture score: 4.4.

[0088] 6 months: Color score: 4.2, Odor score: 4.0, Flavor score: 3.9, Jelly texture score: 4.0.

[0089] Example 4: Day 0: Color score: 4.0, Odor score: 3.9, Flavor score: 3.7.

[0090] 3 months: Color score: 3.2, Odor score: 2.8, Flavor score: 2.5.

[0091] 6 months: Color score: 2.5, Odor score: 2.0, Flavor score: 1.8.

[0092] Jelly texture: No jelly granule design, not scored.

[0093] Example 5: Day 0: Color score: 3.9, Odor score: 3.8, Flavor score: 3.6.

[0094] 3 months: Color score: 3.0, Odor score: 2.5, Flavor score: 2.2.

[0095] 6 months: Color score: 2.3, Odor score: 1.8, Flavor score: 1.5.

[0096] Jelly texture: No jelly granules design, not scored.

[0097] 2. Microbial test data Example 3: 0 days: The activity of Lactobacillus plantarum is 1.2×10 7 CFU / mL, Total colony count < 10 CFU / mL, Molds / Yeasts not detected.

[0098] 3 months: The activity of Lactobacillus plantarum is 9.8×10 6 CFU / mL, Total colony count 5×10 2 CFU / mL, Molds / Yeasts not detected.

[0099] 6 months: The activity of Lactobacillus plantarum is 8.5×10 5 CFU / mL, Total colony count 1.2×10 3 CFU / mL, Molds / Yeasts not detected.

[0100] Examples 2, 4, 5: 0 days: Lactobacillus plantarum not added, Total colony count < 10 CFU / mL, Molds / Yeasts not detected.

[0101] 3 months: Total colony count 2.5×10 3 CFU / mL, Molds / Yeasts < 50 CFU / mL.

[0102] 6 months: Total colony count 1.0×10 4 CFU / mL, Molds / Yeasts 1.2×10 2 CFU / mL.

[0103] 3. Flavonoid retention rate data Based on the initial flavonoid content of Example 1 (100%), the initial content of other examples is affected by the encapsulation process, etc.

[0104] Example 1: 0 days: 100%, 3 months: 61%, 6 months: 40%.

[0105] Example 2: 0 days: 105%, 3 months: 95%, 6 months: 79%.

[0106] Example 3: 0 days: 106%, 3 months: 99%, 6 months: 80%.

[0107] Example 4: 0 days: 93%, 3 months: 70%, 6 months: 55%.

[0108] Example 5: 0 days: 96%, 3 months: 65%, 6 months: 48%.

[0109] III. Conclusions Taste and flavor: Examples 2 and 3: The jelly particles give a "crispy outside and soft inside" taste, the herbal flavor is stable, and the sensory score is significantly higher than that of other groups after 6 months (P < 0.05).

[0110] Examples 4 and 5: Without the protection of jelly particles, the taste is rough and the flavor deterioration is obvious (the score drops by > 30% after 3 months).

[0111] Activity of Lactobacillus plantarum: Example 3: The microcapsule jelly particles effectively protect Lactobacillus plantarum, and the activity still maintains a good protection effect after 6 months.

[0112] Examples 2 / 4 / 5: Probiotics were not added, and the deteriorated flora increased significantly with storage time.

[0113] Flavonoid retention rate: Examples 2 and 3: The microcapsule jelly particles delay oxidative degradation, and the flavonoid retention rate is increased compared with other groups.

[0114] It can be seen that the microcapsule jelly particles (Examples 2 and 3), through double embedding technology (flavonoid + probiotic) and gel network protection, significantly improve the taste of the beverage, the stability of functional components and the activity of probiotics, and are suitable for the development of long-acting functional plant beverages.

[0115] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made.

Claims

1. A method for preparing a corn straw beverage, characterized in that, It includes the following steps: Step (1): Wash the corn straw, dry it, and crush it. Step (2): Add pure water according to a solid-liquid ratio of 1:12 - 16, and soak for 12 - 15 hours to obtain a corn straw mixed solution. Step (3): Extract the corn straw mixed solution under a water bath condition of 80 - 100 °C, extract for 1 - 2 hours each time, repeat the extraction 1 - 3 times, and combine the extracts. Step (4): Coarsely filter the combined extract, and then centrifuge to obtain the supernatant. Step (5): Concentrate the supernatant to obtain a water extract of corn straw. Step (6): The mixed and formulated beverage includes 78 - 700 mg / mL of the water extract of corn straw, 0.30 - 0.40 mg / mL of sucralose, 0.32 - 0.40 mg / mL of citric acid, 0.20 - 0.28 mg / mL of potassium sorbate, and the balance is pure water. Mix them evenly. Step (7): Sterilize and fill the mixed solution to obtain the finished beverage.

2. The preparation method of the corn straw beverage according to claim 1, characterized in that, In step (1), it is crushed to a particle size of ≤5 mm; in step (2), the solid-liquid ratio is 1:14 and it is soaked for 12 hours; in step (3), it is extracted under a water bath condition of 100 °C, extracted for 1 hour each time, and the extraction is repeated 3 times; in step (4), it is centrifuged at 3000 r / min for 10 minutes to obtain the supernatant; in step (5), the supernatant is concentrated to 1 / 3 of the original extract volume to obtain a water extract of corn straw; the mixed and formulated beverage in step (6) includes 700 mg / mL of the water extract of corn straw, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, and 0.28 mg / mL of potassium sorbate; in step (7), the mixed solution is sterilized by ultraviolet light for 10 - 15 minutes and filled into sterilized glass bottles to obtain the finished beverage.

3. The preparation method of the corn straw beverage according to claim 1 or 2, characterized in that In step (5), a carrier is also included. The preparation steps of the carrier are as follows: Mix potato starch nanoparticles and β-cyclodextrin according to a mass ratio of 1:1 - 1.5 to obtain a first mixture. Add a citric acid solution with a mass concentration of 3% to the first mixture, and the addition amount of the citric acid solution is 5 - 8% of the total mass of the first mixture. Stir and react the mixed system. After the reaction, centrifuge to remove free citric acid and dry to obtain the carrier. Mix the water extract of corn straw and the carrier according to a volume-mass ratio of 4 ml:1 g, and treat it at an ultrasonic frequency of 45 kHz and a power of 150 W for 20 minutes; then prepare embedded particles with a particle size of 10 - 30 μm by spray drying, and control the moisture content to ≤4%.

4. The preparation method of the corn straw beverage according to claim 3, characterized in that, The step of stirring and reacting the mixed system, centrifuging to remove free citric acid and drying to obtain the carrier specifically is: Place the mixed system in a constant temperature water bath, control the temperature at 60 °C ± 0.5 °C, stir at a speed of 300 - 400 r / min for 30 minutes, and maintain the pH value of the reaction system at 4.5 ± 0.2 by dropping a 0.1 mol / L sodium hydroxide solution during this period. After the reaction, centrifuge the mixture at 8000 r / min for 10 - 15 minutes, discard the supernatant, and wash the precipitate with deionized water 3 - 5 times until the pH value of the washing solution is 6.5 ± 0.

3. Dry the washed precipitate in a vacuum drying oven at 50 °C ± 2 °C until the moisture content is ≤3% to obtain the carrier.

5. The preparation method of the corn straw beverage according to claim 4, wherein, Step (5) also includes the preparation of microcapsules: Sodium alginate and chitosan are dissolved in deionized water at a mass ratio of 3:1, and inner microcapsules with a particle size of 50 - 80 μm are prepared by electrostatic spraying method; The embedded particles are filled into the inner microcapsules, and the filling rate is 70 - 80% of the microcapsule volume; An outer layer of β - cyclodextrin - potato starch nanoparticle composite film solution is sprayed, and dried at 40°C ± 2°C until the moisture content ≤ 5% to form an outer layer film with a thickness of 2 - 5 μm, obtaining microcapsules.

6. The preparation method of the corn straw beverage according to claim 5, wherein, The microcapsules also include Lactobacillus plantarum. Specifically, it further includes: the embedded particles and Lactobacillus plantarum are mixed at a mass ratio of 1:0.2, and filled into the inner microcapsules by microfluidic negative pressure inhalation method, and the filling rate is 70 - 80% of the microcapsule volume.

7. The preparation method of the corn straw beverage according to claim 5 or 6, characterized in that, The β - cyclodextrin - potato starch nanoparticle composite film solution is obtained through the following steps: β - cyclodextrin and potato starch nanoparticles are mixed at a mass ratio of 1:1 - 2, deionized water is added, and the solid content in the mixed solution is controlled to be 8% ± 0.5%; The mixed solution is heated to 60°C ± 2°C and stirred at a speed of 500 - 600 r / min for 30 - 40 minutes until completely dissolved; During the stirring process, 0.05 mol / L sodium citrate solution is added dropwise to the mixed solution to adjust the pH value to 6.8 ± 0.2; The mixed solution is transferred to an ultrasonic disperser and treated at a frequency of 40 kHz and a power of 100 W for 10 - 15 minutes; The dispersed composite film solution is filtered through a 0.45 μm microporous membrane and left to stand for defoaming at 25°C ± 1°C for 20 - 30 minutes to obtain the β - cyclodextrin - potato starch nanoparticle composite film solution.

8. The preparation method of the corn straw beverage according to claim 7, characterized in that, Step (6) also includes microcapsule jelly particles, and the preparation steps of the microcapsule jelly particles are as follows: The microcapsules and the natural composite colloid solution are mixed at a mass ratio of 1:5 to obtain a mixed solution. The preparation method of the natural composite colloid solution is: using deionized water as a solvent, adding κ - carrageenan, konjac glucomannan and corn straw aqueous extract, wherein the addition amount of κ - carrageenan is 0.8% of the solvent mass, the addition amount of konjac glucomannan is 0.3% of the solvent mass, and the addition amount of corn straw aqueous extract is 10% of the solvent mass; The mixed solution is stirred at 75°C ± 2°C until completely dissolved; The mixed solution is poured into a mold and cooled and solidified at 25°C ± 1°C for 30 - 40 minutes to form a gel block; The gel block is cut into cubic particles with a particle size of 2 - 3 mm to obtain microcapsule jelly particles containing microcapsules.

9. The preparation method of the corn straw beverage according to claim 8, characterized in that, The mixed formulated beverage includes 300 mg / mL of microcapsule jelly particles, 300 mg / mL of corn straw aqueous extract, 0.40 mg / mL of sucralose, 0.36 mg / mL of citric acid, 0.28 mg / mL of potassium sorbate, and the balance is purified water; Slowly stir at 50 - 80 r / min at 40°C ± 2°C for 1 - 2 minutes to form a mixed solution.

10. The application of the corn straw aqueous extract obtained by the preparation method according to claim 1 in the preparation of lipid - lowering drugs or functional beverages.

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