High-nutrition red date and chickpea powder solid beverage and preparation method thereof

Abstract

The invention relates to the technical field of functional solid beverage preparation, in particular to a high-nutrition red date and chickpea powder solid beverage and a preparation method thereof. The solid beverage is prepared by the method. The method comprises the following steps: preparing red date juice and chickpea juice; mixing the red date juice and the chickpea juice according to a mass ratio of 6: 4-7: 3, adding an iron enhancer, a selenium enhancer, a stabilizer, an anti-caking agent and a defoaming agent, homogenizing, and adjusting the pH value to 4.0-5.5 to obtain a mixed solution; sterilizing and concentrating to obtain a concentrate; performing centrifugal spray drying treatment on the concentrate to prepare powder; and fully automatically packaging the powder by using nitrogen-filled aluminum foil to obtain a solid beverage product. The solid beverage product which is high in red date juice clarity, rich in nutrition, high in nutrition retention rate, low in brewing precipitation rate, long in shelf life and good in anti-caking effect can be prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of functional solid beverages, and particularly relates to a high-nutrition red date and chickpea powder solid beverage and a preparation method thereof. Background Art

[0002] The soluble sugar content in red date fruits can reach 30%-40%, and the vitamin C content is as high as 200-500 mg / 100 g, which has the effects of enriching blood and benefiting qi, and immune regulation. However, fresh red dates have a high water content (70%-80%), and are prone to rot and deteriorate after harvesting. About 90% of the fresh red date raw materials need to be processed by drying to be converted into primary products such as red date slices and red date powder and enter the market.

[0003] As a high-protein leguminous crop, chickpeas have a protein content of 20%-25%, a dietary fiber ratio of 12%-18%, are rich in folic acid, potassium, magnesium, phosphorus, zinc, copper and VB1, and also contain a certain amount of niacin, VB6, pantothenic acid, calcium and fiber. Chickpeas have high medicinal value, and have the effects of moistening the lungs, anti-inflammatory, beautifying the face, strengthening bones, strengthening the stomach and detoxifying, and also have physiological functions such as regulating blood sugar and antioxidant, especially having obvious curative effects on diabetes, cardiovascular diseases and stomach diseases. However, due to the starch retrogradation characteristics of chickpea powder, it is easy to cause stratification during brewing, which limits its application in solid beverages.

[0004] With the upgrading of healthy consumption, the market of solid beverages based on natural ingredients has witnessed an explosive growth, with an annual growth rate of more than 12.5%. However, there are generally technical bottlenecks in the existing solid beverages made from red date raw materials or chickpea raw materials.

[0005] Specifically as follows:

[0006] In terms of raw material pretreatment, for red dates, direct crushing followed by single steaming treatment is mostly adopted. And the single steaming treatment requires a long steaming time (such as 60-90 min) and a high steaming temperature (such as 95-100 °C), which will cause a large amount of loss of heat-sensitive components (such as vitamin C) in red dates due to the long-time high temperature of single steaming. The conventional hot air drying process (temperature ≥ 80 °C) will cause the reducing sugar in red date juice to undergo Maillard reaction, which not only affects the product color, but also produces a burnt smell. For the processing of chickpeas, cold water soaking or short-time steaming is often adopted, and the protein dissolution rate is less than 50%, resulting in low utilization rate of protein due to insufficient dissolution, and the nutritional potential of raw materials cannot be fully exerted. In addition, macromolecular substances such as pectin in red date juice are not effectively degraded, resulting in a high turbidity of the juice (light transmittance ≤ 70%), which directly affects the sensory quality of the product.

[0007] In terms of nutritional fortification and stability control, most existing solid beverages rely on a single stabilizer (such as maltodextrin) or excessive addition of nutritional fortifiers (such as trace elements like iron and selenium), resulting in insufficient synergy or potential safety hazards. If the addition of trace elements such as iron and selenium exceeds the limit values in the "Standard for the Use of Food Nutritional Fortifiers (GB14880-2012)" (iron ≤ 5.0 mg / 100 g, selenium ≤ 0.05 mg / 100 g), it is likely to cause metallic off-flavors or toxicity risks. More seriously, the existing nutritional fortification process is extensive. In commercially available products, trace elements (such as iron and selenium) are often added in the form of inorganic salts (ferrous sulfate and sodium selenite), which is likely to cause metallic off-flavors and low bioavailability. At the same time, the interaction between polysaccharides and proteins in the mixed system of red dates and chickpeas easily leads to layering and precipitation after reconstitution. The reconstitution precipitation rate of commercially available products is generally higher than 5%, seriously affecting the consumer experience.

[0008] In the drying and packaging processes, due to inaccurate temperature control in the conventional hot air drying process, it is easy to cause powder caking or increased hygroscopicity. Research shows that the hygroscopicity of red date powder is closely related to its particle size. For example, when the particle size of red date powder ≥ 150 μm, the hygroscopic rate increases significantly, but traditional comminution techniques are difficult to achieve precise control of particle size. The setting of spray drying parameters lacks systematic optimization. If the inlet air temperature is too high (>200 °C), it is likely to cause caramelization reactions, while if it is too low (<160 °C), it will result in a moisture residue > 8%, further exacerbating the caking risk. The oxygen transmission rate of ordinary PE packaging is relatively high (≥ 200 cm 3 / m 2 ·24 h), which causes the water activity of the product to rise during storage, increasing the risk of microbial growth, and the shelf life is usually less than 12 months. Such technical defects not only limit the product quality but also are difficult to meet the urgent needs of consumers for products with "functional synergy, instant solubility, and stability".

[0009] To address the above problems, the industry has tried to optimize by adding anti-caking agents (such as silica) or improving the drying process (such as vacuum freeze-drying), but there are still defects such as high production costs, difficulties in large-scale production, or low nutrient retention rates. Although vacuum freeze-drying can better retain active ingredients, it has high energy consumption, a long production cycle, and is difficult to meet industrial requirements; while adding a single anti-caking agent has limited anti-caking effects on high-sugar systems such as red dates.

[0010] In summary, there is a need to provide a high-nutrition red date and chickpea powder solid beverage and its preparation method to solve the problems of high turbidity of red date juice, extensive nutritional fortification, low nutrient retention rate, high reconstitution precipitation rate, short shelf life, and poor anti-caking effect existing in the prior art. Summary of the Invention

[0011] The object of the present invention is to provide a high-nutrition red date and chickpea powder solid beverage and its preparation method. The specific technical solutions are as follows:

[0012] In a first aspect, the present invention provides a method for preparing a high-nutrition red date and chickpea powder solid beverage, which is characterized by comprising:

[0013] Step S1, raw material pretreatment. Specifically, after washing and removing the pits of red dates, pre-cooking and softening treatment and first enzymolysis treatment are carried out in sequence, and finally, pulping and filtering are carried out to obtain red date juice; after washing and soaking chickpeas, high-pressure steaming treatment is carried out, and then, second enzymolysis treatment is carried out, and finally, pulping and filtering are carried out to obtain chickpea juice; the enzymes used in the first enzymolysis treatment include pectinase; the enzymes used in the second enzymolysis treatment include neutral protease;

[0014] Step S2, mixing and blending. Specifically, the red date juice and the chickpea juice are mixed in a mass ratio of 6:4 to 7:3, and an iron fortifier, a selenium fortifier, a stabilizer, an anti-caking agent and an anti-foaming agent are added. After homogenization treatment, the pH value is adjusted to 4.0 to 5.5 to obtain a mixed liquid; the iron fortifier includes ferrous glycinate; the selenium fortifier includes selenium-enriched yeast; the stabilizer includes maltodextrin and xanthan gum;

[0015] Step S3, sterilization and concentration. Specifically, the mixed liquid is first subjected to pasteurization treatment, and then subjected to vacuum concentration treatment until the solid content is ≥30% to obtain a concentrate;

[0016] Step S4, spray drying. Specifically, the concentrate is subjected to centrifugal spray drying treatment to form a powder, and the particle size of the powder is controlled to be ≤100 μm;

[0017] Step S5, packaging. Specifically, the powder is fully automatically packaged with nitrogen-filled aluminum foil to obtain a solid beverage product; wherein, the residual oxygen content in the solid beverage product is controlled to be ≤3 v / v.%, and the moisture content in the solid beverage product is controlled to be ≤5 wt.%.

[0018] Optionally, the mass percentage of red dates in the red date juice is 15% to 18%; the mass percentage of chickpeas in the chickpea juice is 13% to 15%.

[0019] Optionally, the pre-cooking temperature for the pre-cooking and softening treatment is 90 to 100 °C, and the pre-cooking time is 15 to 25 min; the enzymolysis temperature for the first enzymolysis treatment is 40 to 60 °C, and the enzymolysis time is 20 to 40 min.

[0020] Optionally, the steaming temperature for the high-pressure steaming treatment is 100 to 121 °C, the steaming pressure is 0.1 to 0.15 MPa, and the steaming time is 15 to 30 min; the enzymolysis temperature for the second enzymolysis treatment is 40 to 60 °C, and the enzymolysis time is 20 to 40 min;

[0021] The enzyme used in the second enzymatic hydrolysis treatment further includes cellulase; the mass fraction of the cellulase is 0.05 - 0.2 parts.

[0022] Optionally, the homogenization pressure used in the homogenization treatment is 20 - 40 MPa, and the homogenization time used is 3 - 8 min.

[0023] Optionally, the sterilization temperature used in the pasteurization treatment is 80 - 90 °C, and the sterilization time used is 20 - 40 min; the treatment temperature used in the vacuum concentration treatment is 50 - 70 °C, and the treatment pressure is -0.07 - -0.01 MPa.

[0024] Optionally, the inlet air temperature used in the centrifugal spray drying treatment is 160 - 190 °C, the outlet air temperature used is 75 - 90 °C, and the rotation speed of the atomization disc is 15000 - 20000 rpm.

[0025] Optionally, the solid beverage product includes the following raw material components in mass fractions:

[0026] 50 - 70 parts of red date juice, 20 - 40 parts of chickpea juice, 0.01 - 0.03 parts of iron fortifier, 0.01 - 0.03 parts of selenium fortifier, 10 - 20 parts of maltodextrin, 0.1 - 0.5 parts of xanthan gum, 0.1 - 0.3 parts of anticaking agent, 0.01 - 0.1 parts of defoaming agent, 0.05 - 0.2 parts of pectinase, and 0.05 - 0.2 parts of neutral protease;

[0027] The anticaking agent includes silicon dioxide;

[0028] The defoaming agent includes food-grade polydimethylsiloxane.

[0029] Optionally, the solid beverage product further includes the following raw material components in mass fractions: 5 - 10 parts of granulated sugar and 0.1 - 0.3 parts of citric acid; the granulated sugar is added in the step S2 and before the homogenization treatment for flavoring; the citric acid is added in the step S2 and after the homogenization treatment for adjusting the pH value.

[0030] In a second aspect, the present invention provides a high-nutrition red date and chickpea powder solid beverage, which is prepared by using the preparation method of the high-nutrition red date and chickpea powder solid beverage.

[0031] Applying the technical solution of the present invention has at least the following beneficial effects:

[0032] The preparation method of a high-nutrition red date and chickpea powder solid beverage provided by the present invention can prepare a solid beverage product with high clarity of red date juice, nutritional fortification, high nutritional retention rate, low precipitation rate after reconstitution, long shelf life, and good anti-caking effect. Specifically, in step S1, the red date juice obtained by enzymatic hydrolysis with pectinase and then pulping and filtering has a high clarity, and its light transmittance is increased to more than 93%; the protein dissolution rate of the chickpea juice obtained by enzymatic hydrolysis with neutral protease and then pulping and filtering is increased to more than 85%, fully exerting the nutritional potential of the chickpea raw material; in step S2, mixing the red date juice and the chickpea juice according to a mass ratio of 6:4 to 7:3 breaks through the nutritional and functional limitations of a single raw material; among them, the high protein and dietary fiber of chickpeas provide a sustained-release carrier for the natural sugars of red dates, which can reduce the blood glucose index after reconstitution, prolong the gastric emptying time, and enhance the satiety; further, through the precise fortification of iron fortifier and selenium fortifier, the dual functions of blood enrichment and antioxidant are realized; among them, ferrous glycinate and selenium-enriched yeast exist in the form of organic substances, which not only facilitate the improvement of biological utilization rate, but also can reduce the metallic odor; furthermore, the combined use of maltodextrin and xanthan gum in the stabilizer can synergistically stabilize the system, so that the precipitation rate after reconstitution ≤ 2%; in step S3, pasteurization treatment can ensure that the microbial indicators (total number of colonies ≤ 1000 CFU / g) in the mixed liquid meet the "Hygiene Standard for Solid Beverages GB7101"; the vacuum concentration treatment facilitates the completion of spray drying in step S4; in step S4, centrifugal spray drying treatment is adopted, and the particle size of the powder is controlled ≤ 100 μm, which is convenient for reducing the hygroscopicity of the powder and improving the anti-caking effect of the powder; in step S5, the powder is packaged automatically with nitrogen-filled aluminum foil to obtain a solid beverage product, and the residual oxygen content in the solid beverage product is controlled ≤ 3 v / v.%, and the moisture content ≤ 5 wt.%. On the one hand, it can improve the anti-caking effect of the product, on the other hand, it can extend the shelf life of the product, such as the shelf life is extended to 18 - 24 months, which is 50% - 100% longer than the shelf life of conventional packaging. On the other hand, it can improve the nutritional retention rate, such as the retention rate of vitamin C ≥ 86%.

[0033] In addition to the purposes, features, and advantages described above, the present invention has other purposes, features, and advantages. The following will refer to the drawings for a more detailed description of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0035] Figure 1 is a process schematic diagram of a preparation method of a high-nutrition red date and chickpea powder solid beverage in Example 1;

[0036] Figure 2 It is a test result graph of the light transmittance of each red date juice in Examples 1-2 and Comparative Example 1;

[0037] Figure 3 It is a test result graph of the protein dissolution rate of each chickpea juice in Example 1, Example 3 and Comparative Example 2;

[0038] Figure 4 It is a test result graph of the change of vitamin C retention rate in the solid beverage product prepared in Example 1 with storage time;

[0039] Figure 5 It is a test result graph of the change of moisture content in the solid beverage product prepared in Example 1 with storage time. Detailed implementation manners

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0041] Example 1:

[0042] See Figure 1 , a preparation method of a high-nutrition red date and chickpea powder solid beverage, including:

[0043] Step S1, raw material pretreatment. Specifically, after washing and removing the cores of red dates (specifically Xinjiang grey dates), pre-cooking and softening treatment and the first enzymatic hydrolysis treatment are carried out in sequence. Finally, it is ground into slurry by a colloid mill to a particle size ≤ 0.3 mm, and then clarified red date juice is obtained through centrifugal filtration, with a soluble solid content ≥ 15%; after washing and soaking chickpeas, high-pressure steaming treatment is carried out, and then the second enzymatic hydrolysis treatment is carried out. Finally, it is ground and filtered (specifically using plate-frame filtration with a plate-frame pore size of 0.1 mm) to obtain chickpea juice; the enzyme used in the first enzymatic hydrolysis treatment is pectinase, and the pectinase enzyme activity ≥ 3000 U / g; the enzymes used in the second enzymatic hydrolysis treatment are neutral protease and cellulase, the neutral protease enzyme activity ≥ 50000 U / g, and the cellulase enzyme activity ≥ 1000 U / g;

[0044] Step S2: Mixing and Blending. Specifically, mix the red date juice and the chickpea juice in a mass ratio of 6:4 to 7:3 (specifically 7:3), and add iron fortifier, selenium fortifier, stabilizer, anticaking agent and defoaming agent. After homogenization treatment, adjust the pH value to 4.0 - 5.5 (specifically 4.5) to obtain a mixed liquid; the iron fortifier is ferrous glycinate; the selenium fortifier is selenium-enriched yeast; the stabilizer is maltodextrin (DE value 18 - 20) and xanthan gum (viscosity ≥ 1500 mPa·s);

[0045] Step S3: Sterilization and Concentration. Specifically, first perform pasteurization on the mixed liquid, and then perform vacuum concentration treatment until the solid content ≥ 30% (specifically 35%) to obtain a concentrate;

[0046] Step S4: Spray Drying. Specifically, perform centrifugal spray drying on the concentrate to make it into powder, and control the particle size of the powder ≤ 100 μm;

[0047] Step S5: Packaging. Specifically, use nitrogen-filled (nitrogen purity ≥ 99.9%) aluminum foil (specifically three-layer composite aluminum foil, i.e., PET12μm / AL9μm / PE50μm, oxygen transmission rate ≤ 1 cm 3 / m 2 ·24h) to automatically package the powder to obtain a solid beverage product, with 0.5g / 100g deoxidizer inside; among them, control the residual oxygen content in the solid beverage product ≤ 3 v / v.% (specifically ≤ 1 v / v.%), and control the moisture content in the solid beverage product ≤ 5 wt.%.

[0048] The mass percentage of red dates in the red date juice is 16.67%; the mass percentage of chickpeas in the chickpea juice is 14.28%.

[0049] The precooking temperature for the precooking and softening treatment is 90 - 100°C (specifically 95°C), and the precooking time is 15 - 25 min (specifically 18 min) for softening the red date tissue; the red dates and water are mixed in a mass ratio of 1:5 for precooking in the precooking and softening treatment; the enzymatic hydrolysis temperature for the first enzymatic hydrolysis treatment is 40 - 60°C (specifically 50°C), and the enzymatic hydrolysis time is 20 - 40 min (specifically 30 min).

[0050] The steaming temperature used in the autoclaving treatment is 100 - 121°C (specifically 100°C), the steaming pressure is 0.1 - 0.15 MPa (specifically 0.1 MPa), and the steaming time is 15 - 30 min (specifically 20 min); in the autoclaving treatment, the chickpeas and water are mixed and steamed at a mass ratio of 1:6; the enzymatic hydrolysis temperature used in the second enzymatic hydrolysis treatment is 40 - 60°C (specifically 50°C), and the enzymatic hydrolysis time is 20 - 40 min (specifically 40 min).

[0051] The homogenization pressure used in the homogenization treatment is 20 - 40 MPa, and the homogenization time is 3 - 8 min. The homogenization treatment is completed in a high-pressure homogenizer and requires two homogenization treatments; specifically, the homogenization pressure used in the first homogenization treatment is 20 MPa, and the homogenization time is 2 min, which is used to break large molecular aggregates; the homogenization pressure used in the second homogenization treatment is 30 MPa, and the homogenization time is 3 min, which is used to enhance the system stability.

[0052] The sterilization temperature used in the pasteurization treatment is 80 - 90°C (specifically 85°C), and the sterilization time is 20 - 40 min (specifically 30 min); the treatment temperature used in the vacuum concentration treatment is 50 - 70°C (specifically 60°C), and the treatment pressure is -0.1 - -0.01 MPa (specifically -0.07 MPa).

[0053] The inlet air temperature used in the centrifugal spray drying treatment is 160 - 190°C (specifically 180°C), the outlet air temperature is 75 - 90°C (specifically 85°C), and the rotation speed of the atomizing disk (atomizing disk diameter 120 mm) is 15000 - 20000 rpm (specifically 20000 rpm). In the centrifugal spray drying treatment, the feed flow rate of the concentrate is 400 L / h, and the drying time used is related to the total feed amount of the concentrate. For example, for a concentrate with a total feed amount of 100 mL, the required drying time is about 20 min.

[0054] The solid beverage product comprises the following raw material components in parts by mass:

[0055] 50 - 70 parts (specifically 70 parts) of red date juice, 20 - 40 parts (specifically 30 parts) of chickpea juice, 0.01 - 0.03 parts (specifically 0.03 parts) of iron fortifier, 0.01 - 0.03 parts (specifically 0.03 parts) of selenium fortifier, 10 - 20 parts (specifically 15 parts) of maltodextrin, 0.1 - 0.5 parts (specifically 0.25 parts) of xanthan gum, 0.1 - 0.3 parts (specifically 0.2 parts) of anticaking agent, 0.01 - 0.1 parts (specifically 0.1 parts) of defoaming agent, 0.05 - 0.2 parts (specifically 0.1 parts) of pectinase, 0.05 - 0.2 parts (specifically 0.05 parts) of neutral protease, and 0.05 - 0.2 parts (specifically 0.05 parts) of cellulase;

[0056] The anticaking agent is silicon dioxide;

[0057] The defoaming agent is food - grade polydimethylsiloxane.

[0058] The solid beverage product further includes the following raw material components in parts by mass: 5 - 10 parts (specifically 7.5 parts) of granulated sugar and 0.1 - 0.3 parts (specifically 0.1 part) of citric acid; The granulated sugar is added in step S2 and before the homogenization treatment for flavoring; The citric acid is added in step S2 and after the homogenization treatment for adjusting the pH value.

[0059] Example 2:

[0060] Different from Example 1, in the first enzymatic hydrolysis treatment, the dosage of pectinase is increased to 0.15 parts, and the enzymatic hydrolysis temperature used in the first enzymatic hydrolysis treatment is 55 °C, and the enzymatic hydrolysis time used is 20 min.

[0061] Example 3:

[0062] Different from Example 1, in the second enzymatic hydrolysis treatment, the use of cellulase is cancelled, and the dosage of neutral protease is increased to 0.1 part; The enzymatic hydrolysis time used in the second enzymatic hydrolysis treatment is 30 min.

[0063] Example 4:

[0064] Different from Example 1, the inlet air temperature used in the centrifugal spray drying treatment is 175 °C, and the outlet air temperature used is 80 °C.

[0065] Comparative Example 1:

[0066] Different from Example 1, the first enzymatic hydrolysis treatment is cancelled.

[0067] Comparative Example 2:

[0068] Different from Example 1, the second enzymatic hydrolysis treatment is cancelled.

[0069] Comparative Example 3:

[0070] Different from Example 1, the inlet air temperature used in the centrifugal spray drying treatment is 160 °C, and the outlet air temperature used is 70 °C, that is, the outlet air temperature is too low.

[0071] Comparative Example 4:

[0072] Different from Example 1, the inlet air temperature used in the centrifugal spray drying treatment is 200 °C, and the outlet air temperature used is 95 °C, that is, both the inlet air temperature and the outlet air temperature are too high.

[0073] Comparative Example 5:

[0074] Different from Example 1, the centrifugal spray drying treatment uses traditional hot air drying, that is, both the inlet air temperature and the outlet air temperature are 80 °C, and the drying time is 12 h.

[0075] Samples of the red date juices obtained in step S1 of Examples 1 to 2 and Comparative Example 1 were taken respectively for transmittance testing. The test results are shown in Figure 2 .

[0076] The transmittance testing method is as follows: Use a spectrophotometer of model Shimadzu UV-2600i to test the transmittance of the red date juice at 600 nm.

[0077] It can be seen from Figure 2 that compared with Comparative Example 1, the red date juices prepared in Examples 1 to 2 of the present invention all have relatively high transmittances, which are 96% and 93% respectively, while the transmittance of the red date juice prepared in Comparative Example 1 is only 70%. This is because the red date juice obtained by enzymolysis with an appropriate amount of pectinase and then pulping and filtering has a relatively high clarity, and its transmittance is increased to more than 93%.

[0078] Samples of the chickpea juices obtained in step S1 of Example 1, Example 3 and Comparative Example 2 were taken respectively for protein dissolution rate testing. The test results are shown in Figure 3 .

[0079] The protein dissolution rate testing method is as follows: Use the Kjeldahl method for testing.

[0080] It can be seen from Figure 3It is known that, compared with Comparative Example 2, the chickpea juice prepared in Example 1 and Example 3 of the present invention both have a relatively high protein dissolution rate, which are 92% and 89% respectively, while the protein dissolution rate of the chickpea juice prepared in Comparative Example 2 is only 48%. This is because the protein dissolution rate of the chickpea juice obtained by enzymolysis with neutral protease or combined enzymolysis of neutral protease and cellulase followed by pulping and filtration is increased to more than 85%, giving full play to the nutritional potential of the chickpea raw material. Among them, in Example 1 of the present invention, the chickpea juice obtained by combined enzymolysis of neutral protease and cellulase followed by pulping and filtration can also increase the degradation rate of chickpea fiber to 85%, reducing the residue of soybean dregs.

[0081] The mixed liquid obtained in step S2 of Example 1 was sampled respectively for inductively coupled plasma mass spectrometry (ICP-MS) detection of the distribution of iron and selenium elements, and the Caco-2 cell model was used to evaluate the bioavailability of iron and selenium.

[0082] Test results: The relative standard deviation (RSD) of the uniformity of iron element distribution ≤ 3.5%, and the bioavailability reaches 88%; the RSD of the uniformity of selenium element distribution ≤ 4.2%, and the bioavailability of selenium ≥ 85%; the DPPH free radical scavenging rate of selenium ≥ 92%; the iron element and selenium element comply with the "Standard for the Use of Food Nutritional Fortifiers (GB14880-2012)" (iron ≤ 5.0 mg / 100 g, selenium ≤ 0.05 mg / 100 g).

[0083] The solid beverage products prepared in Example 1 were sampled respectively for particle size distribution test and reconstitution sedimentation rate test. The particle size distribution test method is as follows: Adjust the Zeta potential to -35 mV, and detect the particle size distribution by a laser particle size analyzer of model Malvern Mastersizer 3000 (Malvern Instruments, UK). The reconstitution sedimentation rate test method is as follows: Mix the solid beverage product and hot water at a mass ratio of 1:10, and let it stand for 1 hour. Among them, the temperature of the hot water is 70 °C, and the sedimentation rate is determined by the centrifugal gravimetric method.

[0084] Test results: The average particle size D50 of the solid beverage product ≤ 5 μm, and the absolute value of the Zeta potential ≥ 30 mV. The sedimentation rate after reconstitution ≤ 1.2%, the dissolution time is shortened to 8 seconds, and there is no visible suspension.

[0085] The solid beverage products prepared in Example 4 were sampled respectively for testing powder morphology and particle size distribution, hygroscopicity, moisture content, flowability angle of repose, and sensory evaluation of burnt taste. The methods for testing powder morphology and particle size were as follows: The powder morphology of the solid beverage products was observed by a scanning electron microscope (SEM) of model Hitachi SU8010 (Hitachi Corporation), and the particle size distribution was calculated. The method for testing hygroscopicity was as follows: The solid beverage products were placed in an environment of 25 °C and a relative humidity of RH75% for 24 h, and the hygroscopicity rate was obtained by the static weighing method. The method for testing moisture content was as follows: The moisture content data of the solid beverage products were determined by the direct drying method (in accordance with "GB 5009.3-2016 Determination of Moisture in Foods"), and the calculation formula was: Moisture content (%) = [(m1 - m2) / m1] × 100%, where m1 was the initial mass of the sample and m2 was the mass of the sample after constant weight. The method for testing flowability angle of repose was as follows: The flowability of the powder of the solid beverage products was measured by a repose angle tester of model Hosokawa Powder Tester PT-X. The powder was freely dropped and piled up into a conical shape, and the angle between the conical slope and the horizontal plane was measured. The method for sensory evaluation of burnt taste was as follows: 10 trained sensory evaluators conducted blind tests on the solid beverage products and scored them according to "GB / T 16291-2012 General Guidelines for the Selection, Training and Management of Sensory Evaluators" (0-10 points, 0 points indicating no burnt taste and 10 points indicating severe burnt taste).

[0086] Test results: The particle size D90 of the powder ≤ 100 μm, and the sphericity ≥ 0.85. The hygroscopicity rate decreased to 2.8%, and the moisture content ≤ 4.2%. The flowability angle of repose ≤ 32°. The sensory evaluation score for burnt taste was 0 points, that is, no burnt taste was generated.

[0087] The solid beverage products prepared in Example 1 and Comparative Examples 3-5 were sampled respectively for testing vitamin C retention rate, moisture content, and hygroscopicity rate. The test results are shown in Table 1. Among them, the method for testing vitamin C retention rate was as follows: It was determined by high performance liquid chromatography (HPLC), and the model of the high performance liquid chromatograph used was Agilent1260Infinity II high performance liquid chromatograph (the high performance liquid chromatography method mentioned below used the same model of high performance liquid chromatograph as here). The methods for testing moisture content and hygroscopicity rate refer to the testing methods in Example 4.

[0088] Table 1 Test Results of Vitamin C Retention Rate, Moisture Content, and Hygroscopicity Rate

[0089]

[0090]

[0091] As can be seen from Table 1, compared with Comparative Examples 3-5, the solid beverage product prepared in Example 1 of the present invention has a higher vitamin C retention rate, lower moisture content and moisture absorption rate. This shows that using appropriate centrifugal spray drying treatment parameters is convenient for reducing the hygroscopicity of the powder and increasing the vitamin C retention rate.

[0092] Samples of the solid beverage product prepared in Example 1 were respectively taken for tests on the microbial content, the change of vitamin C retention rate with storage time, and the change of moisture content with storage time. The test results are shown in Figures 4 to 5 . Among them, the method for testing the microbial content is as follows: The solid beverage product is placed in an environment at 37°C and a relative humidity of RH75% for 6 months, and the total number of colonies (CFU / g) and the detection limit of molds are obtained by plate counting method and molecular biology detection. The method for testing the change of vitamin C retention rate with storage time is as follows: High performance liquid chromatography (HPLC) is used to quantitatively analyze and determine the data of the change of vitamin C retention rate of the solid beverage product with storage time. The initial vitamin C content is set to 100%, and the calculation formula is: retention rate (%) = (vitamin C content after storage / initial vitamin C content) × 100%. The method for testing the change of moisture content with storage time is as follows: The direct drying method (in accordance with "GB 5009.3-2016 Determination of Moisture in Foods") is used to determine the data of the change of moisture content of the solid beverage product with storage time. The calculation formula is: moisture content (%) = [(m1 - m2) / m1] × 100%, where m1 is the initial mass of the sample and m2 is the mass of the sample after constant weight.

[0093] Test results of microbial content: The total number of colonies ≤ 800 CFU / g, and no molds were detected.

[0094] As can be seen from Figure 4 , as the storage time prolongs, the vitamin C retention rate continuously decreases. When the storage time extends from 0 days to 18 months, the vitamin C retention rate decreases from 100% to 86%, still showing a relatively high vitamin C retention rate.

[0095] As can be seen from Figure 5 , as the storage time prolongs, the moisture content continuously increases. When the storage time extends from 0 days to 18 months, the moisture content increases from 4.2% to 5.1%, still showing a relatively low moisture content.

[0096] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a high-nutrition red date and chickpea powder solid beverage, characterized in that, Including: Step S1: Pretreatment of raw materials. Specifically, after washing and pitting red dates, perform precooking softening treatment and the first enzymatic hydrolysis treatment in sequence. Finally, beat into pulp and filter to obtain red date juice. After washing and soaking chickpeas, perform high-pressure steaming treatment, then perform the second enzymatic hydrolysis treatment, and finally, beat into pulp and filter to obtain chickpea juice. The enzyme used in the first enzymatic hydrolysis treatment includes pectinase. The enzyme used in the second enzymatic hydrolysis treatment includes neutral protease. Step S2: Mixing and blending. Specifically, mix the red date juice and the chickpea juice according to a mass ratio of 6:4 to 7:3, and add iron fortifier, selenium fortifier, stabilizer, anticaking agent, and defoamer. After homogenization treatment, adjust the pH value to 4.0 - 5.5 to obtain a mixed solution. The iron fortifier includes ferrous glycinate. The selenium fortifier includes selenium-enriched yeast. The stabilizer includes maltodextrin and xanthan gum. Step S3: Sterilization and concentration. Specifically, first perform pasteurization treatment on the mixed solution, and then perform vacuum concentration treatment until the solid content ≥ 30% to obtain a concentrate. Step S4: Spray drying. Specifically, perform centrifugal spray drying treatment on the concentrate to make it into powder, and control the particle size of the powder ≤ 100 μm. Step S5: Packaging. Specifically, use nitrogen-filled aluminum foil for full-automatic packaging of the powder to obtain a solid beverage product. Among them, control the residual oxygen content in the solid beverage product ≤ 3 v / v.%, and control the moisture content in the solid beverage product ≤ 5 wt.%.

2. The preparation method of the high-nutrition red date and chickpea powder solid beverage according to claim 1, characterized in that, The mass percentage of red dates in the red date juice is 15% - 18%. The mass percentage of chickpeas in the chickpea juice is 13% - 15%.

3. The preparation method of the high-nutrition red date and chickpea powder solid beverage according to claim 1, wherein The precooking temperature used in the precooking softening treatment is 90 - 100 °C, and the precooking time is 15 - 25 min. The enzymatic hydrolysis temperature used in the first enzymatic hydrolysis treatment is 40 - 60 °C, and the enzymatic hydrolysis time is 20 - 40 min.

4. The preparation method of the high-nutrition red date and chickpea powder solid beverage according to claim 1, characterized in that, The steaming temperature used in the high-pressure steaming treatment is 100 - 121 °C, the steaming pressure is 0.1 - 0.15 MPa, and the steaming time is 15 - 30 min. The enzymatic hydrolysis temperature used in the second enzymatic hydrolysis treatment is 40 - 60 °C, and the enzymatic hydrolysis time is 20 - 40 min. The enzyme used in the second enzymatic hydrolysis treatment also includes cellulase. The mass fraction of the cellulase is 0.05 - 0.2 parts.

5. The preparation method of the high-nutrition red date and chickpea powder solid beverage according to claim 1, wherein The homogenization pressure used in the homogenization treatment is 20 - 40 MPa, and the homogenization time is 3 - 8 min.

6. The preparation method of the high-nutrition red date and chickpea powder solid beverage according to claim 1, characterized in that, The sterilization temperature used in the pasteurization treatment is 80 - 90 °C, and the sterilization time is 20 - 40 min. The treatment temperature used in the vacuum concentration treatment is 50 - 70 °C, and the treatment pressure is -0.07 - -0.01 MPa.

7. The preparation method of the high-nutrition red date and chickpea powder solid beverage according to claim 1, characterized in that The inlet air temperature used in the centrifugal spray drying treatment is 160 - 190 °C, the outlet air temperature is 75 - 90 °C, and the rotation speed of the atomization disc is 15000 - 20000 rpm.

8. The preparation method of the high-nutrition red date and chickpea powder solid beverage according to any one of claims 1 to 7, characterized in that, The solid beverage product includes the following raw material components in mass fractions: 50 - 70 parts of red date juice, 20 - 40 parts of chickpea juice, 0.01 - 0.03 parts of iron fortifier, 0.01 - 0.03 parts of selenium fortifier, 10 - 20 parts of maltodextrin, 0.1 - 0.5 parts of xanthan gum, 0.1 - 0.3 parts of anticaking agent, 0.01 - 0.1 parts of defoaming agent, 0.05 - 0.2 parts of pectinase and 0.05 - 0.2 parts of neutral protease; The anticaking agent includes silicon dioxide; The defoaming agent includes food-grade polydimethylsiloxane.

9. The preparation method of the high-nutrition red date and chickpea powder solid beverage according to claim 8, characterized in that, The solid beverage product further includes the following raw material components in parts by mass: 5 - 10 parts of granulated sugar and 0.1 - 0.3 parts of citric acid; the granulated sugar is added in the step S2 and before the homogenization treatment for flavoring; the citric acid is added in the step S2 and after the homogenization treatment for adjusting the pH value.

10. A high-nutrition red date and chickpea powder solid beverage, characterized in that, Prepared by using the preparation method of the high-nutrition red date and chickpea powder solid beverage as described in claim 9.

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