Highland barley beta-glucan and preparation method thereof

Abstract

The present invention relates to the field of plant-derived polysaccharide processing, and more particularly to a kind of highland barley beta-glucan and preparation method thereof, the method including alkaline extraction or acid extraction; alkaline extraction is for first mixing highland barley powder with calcium hydroxide solution and carrying out heating extraction to obtain alkaline extract, then adding citric acid to the alkaline extract and neutralizing to produce precipitation, filtering, and obtaining alkali-soluble highland barley beta-glucan extract; acid extraction is for mixing highland barley powder with citric acid solution and carrying out heating extraction to obtain acid extract, then adding calcium hydroxide solution to the acid extract and neutralizing to produce precipitation, filtering, and obtaining acid-soluble highland barley beta-glucan extract. The method greatly reduces the alkali consumption and water consumption during the extraction process, effectively improving the extraction rate and lipophilicity of highland barley beta-glucan. Compared with the highland barley beta-glucan prepared by other existing methods, the highland barley beta-glucan prepared by the present invention has a significantly improved alpha-amylase inhibition rate, and has greater application potential in low GI food.

Description

Technical Field

[0001] The present invention relates to the field of plant-derived polysaccharide processing, and in particular to highland barley beta-glucan and a preparation method thereof. Background Art

[0002] Highland barley, a high-quality highland cereal crop, possesses higher nutritional value and health benefits than more common grains such as rice and wheat. Its harsh growing environment facilitates the accumulation of a range of bioactive compounds and nutrients, including high levels of phenolic compounds, dietary fiber, particularly β-glucan, and certain essential amino acids, making it a promising candidate for development as a functional food. Compared to common barley, a prominent feature of highland barley is its high content of β-glucan, a non-starch polysaccharide composed of alternating β-(1→3) and β-(1→4) glycosidic bonds and composed of pyranose glucose as its basic unit. Over the past few decades, research has focused on the extraction and structural elucidation of β-glucan, revealing a variety of health benefits, including antioxidant, anti-inflammatory, anti-diabetic, anti-obesity, intestinal environmental improvement, cardioprotective, and anti-cancer effects. Many countries recommend the consumption of whole grains, barley, and foods containing β-glucan to reduce total cholesterol, low-density lipoprotein cholesterol, and the risk of coronary heart disease and colorectal cancer. Therefore, the potential application value of β-glucan in the fields of medicine, food, etc. is worthy of further development and utilization.

[0003] Similar to other non-starch polysaccharides, the extraction process significantly influences the structure and function of β-glucan. Currently, traditional β-glucan extraction methods primarily include water extraction, alkaline extraction, acid extraction, enzymatic extraction, or a combination of these methods. Because physical extraction methods yield relatively low β-glucan content, the current mainstream extraction method involves grinding and screening highland barley to inactivate endogenous glucanases. The extract is then extracted in a dilute alkaline or acid solution at a certain temperature for a period of time, which then requires neutralization. Finally, the extract is repeatedly precipitated with a precipitant (e.g., ethanol, acetone, or other organic reagents) to obtain a polysaccharide solution. This process is relatively cumbersome. When choosing an extraction solvent, strong bases (e.g., NaOH, KOH) and acids (e.g., perchloric acid, sulfuric acid, or hydrochloric acid) are generally used to extract β-glucan. For example, the common alkaline extraction method primarily uses NaOH and other reagents as the extraction solvent to obtain a β-glucan extract from the grain. The extract is then acidified, neutralized, and then precipitated with alcohol. However, a large amount of soluble salts will be produced during this extraction process, and β-glucan has a high solubility. The two are dissolved in the same system, which undoubtedly increases the difficulty of purification. Therefore, in order to obtain high-purity β-glucan, desalination (nanofiltration, alcohol precipitation, etc.) treatment is required. In this process, a large amount of wastewater will be generated or alcohol will be consumed, resulting in a large amount of energy consumption, which is not conducive to the development of a green environment.

[0004] Considering that traditional alkaline or acidic methods for extracting β-glucan have the disadvantages of high water consumption or ethanol consumption, which leads to high processing costs, the extraction process needs to be optimized. Summary of the Invention

[0005] In order to solve the problems mentioned in the above-mentioned prior art, the present invention provides a method for preparing highland barley β-glucan, comprising alkaline extraction or acid extraction,

[0006] The alkaline extraction comprises the following steps: firstly mixing highland barley powder with a calcium hydroxide (Ca(OH)2) solution and performing heating extraction to obtain an alkaline extract; then adding citric acid (C6H8O6) to the alkaline extract to neutralize and produce a precipitate; and filtering to obtain an alkaline-soluble highland barley β-glucan extract;

[0007] The acid extraction is to mix highland barley powder with citric acid (C6H8O6) solution and heat the mixture to obtain an acid extract, then add calcium hydroxide (Ca(OH)2) solution to the acid extract to neutralize the solution and generate a precipitate, and filter the solution to obtain an acid-soluble highland barley β-glucan extract.

[0008] In one embodiment, after the alkaline extraction, the precipitate obtained in the alkaline extraction is mixed with water, and then citric acid (C6H8O6) is added, and the pH of the system is adjusted to 2-4 and then heated for extraction, and then calcium hydroxide (Ca(OH)2) solution is added to neutralize the precipitate, and the precipitate is filtered to obtain an acid-soluble highland barley β-glucan extract.

[0009] This step continues to extract the polysaccharides remaining in the precipitate. As the amount of C6H8O6 increases, the system becomes acidic and the precipitate disappears. Therefore, acid-soluble highland barley β-glucan can be extracted in an acidic system, further improving the extraction rate of highland barley β-glucan.

[0010] In one embodiment, after the acid extraction, the precipitate obtained in the acid extraction is added to a calcium hydroxide (Ca(OH)2) solution, and the system pH is adjusted to 9-10 and then heated for extraction, and then citric acid (C6H8O6) is added to neutralize the precipitate, and the precipitate is filtered to obtain an alkali-soluble barley β-glucan extract.

[0011] This step continues to extract the polysaccharides remaining in the precipitate. As the amount of (Ca(OH)2) solution increases, the system becomes alkaline and the precipitate disappears. Therefore, alkali-soluble highland barley β-glucan can be extracted under the alkaline system, further improving the extraction rate of highland barley β-glucan.

[0012] In one embodiment, in the alkaline extraction, the ratio of the highland barley powder to the calcium hydroxide (Ca(OH)2) solution is 1 g: 15 mL to 30 mL;

[0013] In the acid extraction, the ratio of the highland barley powder to the citric acid (C6H8O6) solution is 1g:15mL to 25mL.

[0014] In one embodiment, the calcium hydroxide (Ca(OH)2) solution is obtained by mixing Ca(OH)2 and water in a ratio of 1 g: 25 mL to 500 mL.

[0015] In one embodiment, the heating extraction temperature range of the alkaline extraction and the acid extraction is 55°C to 95°C.

[0016] In one embodiment, the heating extraction time of the alkaline extraction and the acid extraction is in the range of 1 hour to 3 hours.

[0017] In one embodiment, during the alkaline extraction process, the condition for neutralizing Ca(OH)2 with C6H8O6 is that the molar ratio of C6H8O6 to Ca(OH)2 is 2:1;

[0018] During the acid extraction process, the condition for the neutralization of C6H8O6 by Ca(OH)2 is that the molar ratio of Ca(OH)2 to C6H8O6 is 1:2.

[0019] In one embodiment, the alkali-soluble highland barley β-glucan extract and / or the acid-soluble highland barley β-glucan extract are further concentrated under reduced pressure, dried, and then mixed to obtain a solid highland barley β-glucan product.

[0020] The present invention provides highland barley beta-glucan, which is prepared by any of the above preparation methods.

[0021] Based on the above, compared with the prior art, the preparation method of highland barley β-glucan provided by the present invention has the following technical principles and effects:

[0022] By heating and extracting in an alkaline solution environment provided by Ca(OH)2 or in an acidic solution environment provided by C6H8O6, the extract is reacted with C6H8O6 and Ca(OH)2 to generate calcium citrate (an organic calcium salt) which is easy to separate, and filtering to obtain an alkali-soluble β-glucan extract / acid-soluble β-glucan extract, the need for long-term removal of soluble salts generated during the extraction process or the use of ethanol under other acid-base extraction processes is avoided, and the alkali consumption and water consumption during the extraction process are greatly reduced. At the same time, this method can significantly improve the extraction rate, lipophilicity and α-amylase inhibition rate of the highland barley β-glucan prepared by it. Therefore, compared with the highland barley β-glucan prepared by other existing methods, the highland barley β-glucan prepared by the present invention has greater application potential in low-GI foods.

[0023] Other features and beneficial effects of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other beneficial effects of the present invention can be achieved and obtained by the contents shown in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the effect of different concentrations of Ca(OH)2 solution on the extraction of highland barley β-glucan.

[0025] Figure 2 Schematic diagram of the effect of different extraction temperatures on the extraction of highland barley β-glucan.

[0026] Figure 3 Schematic diagram of the effect of different extraction times on the extraction of highland barley β-glucan.

[0027] Figure 4 Schematic diagram of the effect of different concentrations of NaOH solution on the extraction of highland barley β-glucan.

[0028] Figure 5 Schematic diagram of the effect of highland barley β-glucan prepared by different methods on the inhibition rate of α-amylase. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and should not be understood as limiting the present invention; it should be further understood that the terms used in the present invention should be understood to have meanings consistent with the meanings of these terms in the context of this specification and in the relevant fields, and should not be understood in an idealized or overly formal sense, unless explicitly defined as such in the present invention.

[0031] In order to demonstrate that the preparation method of highland barley β-glucan provided by the present invention has outstanding technical effects compared with the prior art, the present invention will be combined with the following examples and comparative examples to evaluate the extraction rate and lipophilicity of β-glucan, as well as the alkali consumption and water consumption of the entire preparation process. The specific test methods and calculation formulas of the relevant indicators are as follows:

[0032] (1) Extraction rate (acid-soluble / alkali-soluble β-glucan):

[0033] The purity of β-glucan is determined using the Congo red method. The principle is that β-glucan can specifically bind to Congo red dye, and the binding product has obvious light absorption at 550nm. The specific operation is as follows:

[0034] First, a standard curve for different β-glucan contents was drawn. A β-glucan standard solution was prepared at a concentration of 0.1 mg / mL and diluted to a series of concentration gradients of 0.01, 0.02, 0.04, 0.06, 0.08, and 0.1 mg / mL. Then, 1.0 mL of each BBG standard solution was added to 4.0 mL of Congo red solution and mixed thoroughly. After reacting in the dark at 25°C for 10 minutes, 200 mL of the solution was aspirated and dripped into a 96-well plate. The absorbance of the solution was measured at 550 nm using a biotech microplate reader, and a standard curve was drawn. By adjusting the concentration of the BBG sample solution to be within the range of the standard curve, the absorbance of the BBG sample solution was measured using the above method, and the β-glucan content in the sample was calculated using the standard curve.

[0035] Wherein: extraction rate = [total amount of extracted β-glucan (g) / total amount of BBG in highland barley flour (g)] × 100%.

[0036] (2) Lipophilicity:

[0037] Accurately weigh 1.0 g of β-glucan (wi), mix it with 10 g of soybean oil, let it stand for 30 minutes, and then centrifuge (8000 × g, 15 minutes). Remove the supernatant oil and record the final weight (wf). Calculate the lipophilicity using the formula (g) = wf - wi.

[0038] (3) Reduction percentage of alkali consumption and water consumption:

[0039] Reduction percentage (%) = [(A1-A0) / A1] x 100%;

[0040] A1-Alkali consumption (water consumption) of traditional scheme; A0-Alkali consumption (water consumption) of improved scheme.

[0041] The present invention provides the following embodiments

[0042] Example 1 - Effect of different concentrations of Ca(OH)2 solution on the extraction of highland barley β-glucan

[0043] First, Ca(OH)2 and water were prepared according to the weight-to-volume ratios of 1:250, 1:150, 1:75, and 1:50 (unit: g / mL) to obtain 4 groups of Ca(OH)2 solutions with different concentrations.

[0044] Then, 100 g of highland barley powder was weighed and mixed with the above-mentioned Ca(OH)2 solution in a ratio of 1 g: 30 mL. The extraction temperature was set to 95°C. After indirect stirring and extraction for 2 hours, C6H8O6 solution was added to each group of extracts to neutralize them (the molar ratio of C6H8O6 to Ca(OH)2 was 2:1) to produce precipitation. The filtrate was filtered and collected to obtain the alkali-soluble highland barley β-glucan extract.

[0045] Then, each group of precipitates was stirred and mixed with water in a weight ratio of 1:15, and C6H8O6 was continued to be added dropwise until the pH of the system reached 4. The indirect stirring extraction was continued at 95°C for 2 hours. Then, Ca(OH)2 solution was added to the extract to neutralize it (the molar ratio of Ca(OH)2 to C6H8O6 was 1:2) to produce a precipitate, which was filtered to obtain an acid-soluble highland barley β-glucan extract.

[0046] Finally, the alkali-soluble highland barley β-glucan solution and the acid-soluble highland barley β-glucan extract obtained in each group were respectively concentrated under reduced pressure, dried, and then mixed to prepare a solid highland barley β-glucan product.

[0047] Effects of different concentrations of Ca(OH)2 solution on the extraction rate and lipophilicity of highland barley β-glucan Figure 1 As shown, from Figure 1 It can be seen that in this embodiment, when Ca(OH)2 and water are mixed at a ratio of 1 g:75 mL, the extraction rate of highland barley β-glucan reaches a maximum value (9.4%). The lipophilicity of β-glucan tends to be stable (1.88 g).

[0048] Example 2 - Effect of extraction temperature on the extraction effect of highland barley β-glucan

[0049] Prepare 5 portions of Ca(OH)2 solution obtained by mixing Ca(OH)2 and water in a ratio of 1g:125mL, then weigh 100g of highland barley powder and mix them with the above-mentioned Ca(OH)2 solution in a ratio of 1g:15mL, and set the extraction temperature to 55℃, 65℃, 75℃, 85℃ and 95℃ respectively. After indirect stirring and extraction for 2h, add C6H8O6 solution to each group of extracts to neutralize them (the molar ratio of C6H8O6 to Ca(OH)2 is 2:1) to produce a precipitate, filter, and collect the filtrate, which is the alkali-soluble highland barley β-glucan extract.

[0050] The precipitates obtained from each group were stirred and mixed with water in a weight ratio of 1:10, and C6H8O6 was continued to be added dropwise until the pH of the system reached 2. The extraction was continued with indirect stirring at 95°C for 2 hours, and then Ca(OH)2 solution was added to neutralize it (the molar ratio of Ca(OH)2 to C6H8O6 was 1:2) to produce a precipitate, which was filtered to obtain an acid-soluble highland barley β-glucan extract.

[0051] Finally, the alkali-soluble highland barley β-glucan solution and the acid-soluble highland barley β-glucan extract obtained in each group were respectively concentrated under reduced pressure, dried, and then mixed to prepare a solid highland barley β-glucan product.

[0052] Effects of different extraction temperatures on the extraction rate and lipophilicity of highland barley β-glucan Figure 2 As shown in the data, in this embodiment, when the extraction temperature is 75°C, the extraction rate of highland barley β-glucan reaches a stable level (9.8%), while when the temperature is 85°C, the lipophilicity of β-glucan reaches a stable level (1.91g).

[0053] Example 3 - Effect of extraction time on the extraction effect of highland barley β-glucan

[0054] Prepare 3 portions by mixing Ca(OH)2 and water in a ratio of 1g:125mL, then weigh 100g of highland barley powder and mix them with the above-mentioned Ca(OH)2 solution in a ratio of 1g:15mL, set the extraction temperature to 85℃, and set the indirect stirring extraction time to 1h, 2h and 3h respectively, add C6H8O6 to each group of extracts to neutralize it (wherein the molar ratio of C6H8O6 to Ca(OH)2 is 2:1) to produce a precipitate, filter, and collect the filtrate, which is the alkali-soluble highland barley β-glucan extract.

[0055] Then, each group of precipitates was stirred and mixed with water in a weight ratio of 1:10, and C6H8O6 was continued to be added dropwise until the pH of the system reached 2. Each group continued to be indirectly stirred and extracted at 95°C for the same time as before, and then Ca(OH)2 solution (wherein the molar ratio of Ca(OH)2 to C6H8O6 was 1:2) was added to produce precipitation, which was filtered to obtain acid-soluble highland barley β-glucan extract.

[0056] Finally, the alkali-soluble highland barley β-glucan solution and the acid-soluble highland barley β-glucan extract obtained in each group were respectively concentrated under reduced pressure, dried, and then mixed to prepare a solid highland barley β-glucan product.

[0057] Effects of different extraction times on the extraction of highland barley β-glucan Figure 3As shown, the extraction rate of the extraction time of 2h or 3h (both about 9.8%) is significantly higher than that of the extraction time of 1h, and the β-glucan obtained with an extraction time of 3h has the highest lipophilicity (about 2.12g).

[0058] The present invention also provides the following comparative examples

[0059] Comparative Example 1 - Conventional NaOH-HCl extraction

[0060] Four groups of NaOH solutions with mass concentrations of 3%, 5%, 7% and 10% were prepared.

[0061] Weigh 100 g of highland barley powder and mix with NaOH solution at a ratio of 1 g: 15 mL. Set the extraction temperature to 95 ° C. After indirect stirring and extraction for 3 hours, add HCl solution to the above extract and adjust it to neutral (the molar ratio of NaOH to HCl is 1:1). Filter out the highland barley powder residue and collect the filtrate, which is the alkali-soluble highland barley β-glucan extract.

[0062] The highland barley residue and water were then stirred and mixed in a weight ratio of 1:10, and HCl solution was continued to be added dropwise to adjust the pH of the system to 2. The extraction was continued at 95°C with indirect stirring for 3 hours. NaOH solution (wherein the molar ratio of NaOH to HCl was 1:1) was added to the above extract, and the mixture was filtered to obtain an acid-soluble highland barley β-glucan extract.

[0063] Finally, the alkali-soluble highland barley β-glucan extract and the acid-soluble highland barley β-glucan extract obtained in each group were subjected to nanofiltration desalination treatment respectively, and then dried to obtain a solid highland barley β-glucan product.

[0064] according to Figure 4 As shown in Figure 2, when the concentration of sodium hydroxide solution is 7%, the yield of highland barley beta-glucan reaches maximum value, which is only 7.9%. The present embodiment also adopts alcohol precipitation to replace the nanofiltration in the test group with a concentration of 7% of the above-mentioned sodium hydroxide solution to carry out desalination. The specific alcohol precipitation method is to slowly add 95% edible ethanol to the alkali-soluble highland barley beta-glucan extract and the acid-soluble highland barley beta-glucan extract to obtain until the ethanol concentration of the system reaches 80%. After alcohol precipitation for 12h at 4°C, centrifugal 15min is used to obtain precipitate. The precipitate is washed twice with absolute ethanol respectively then, and the ethanol is removed by vacuum concentration after adding water to redissolve. The solid highland barley beta-glucan finished product is dried afterwards, and its extraction yield is about 8.7% (see Figure 2). Figure 4 ), it can be seen that the extraction rate of alcohol precipitation desalination is higher than that of nanofiltration desalination.

[0065] In addition, calculations show that, compared with Comparative Example 1, the alkali consumption of Example 1 and Example 2 is reduced by approximately 70%, and the water consumption is reduced by approximately 86%.

[0066] It can be seen that in Comparative Example 1, NaOH and HCl are used to extract highland barley β-glucan, and subsequent desalination by nanofiltration or alcohol precipitation is required, which not only consumes a large amount of alkali and water but also causes loss of highland barley β-glucan during the treatment process.

[0067] Comparative Example 2 - Conventional hot water extraction

[0068] Highland barley flour (100 g) and water were stirred evenly at a material-liquid ratio of 1:10, the extraction temperature was 95° C., the extraction time was 2 h, and the process was repeated 3 times). After centrifugation, the precipitate was extracted twice with hot water, the supernatants were combined, and 95% edible ethanol was slowly added to the obtained supernatant until the ethanol concentration of the system reached 80%. After alcohol precipitation at 4° C. for 12 h, the precipitate was centrifuged for 15 min to obtain a precipitate, which was then washed twice with anhydrous ethanol, redissolved in water, and then concentrated in vacuo to remove ethanol. The solid highland barley β-glucan product was obtained by freeze-drying.

[0069] After testing, the conventional hot water extraction of highland barley β-glucan has an extraction rate of only 5.1%, which is much lower than the extraction rate of the present invention, and its lipophilic capacity is 1.72g, which is also lower than the alkaline extraction (the optimal value of the embodiment) compared with the same period last year.

[0070] A large number of existing studies have shown that plant-derived polysaccharides have the effect of lowering blood sugar. They may effectively inhibit the activity of salivary and intestinal α-amylase in humans and other animals, hinder the decomposition and digestion of carbohydrates such as starch, and have physiological effects such as reducing food intake, controlling weight gain, slowing fat accumulation and lowering blood sugar levels. Therefore, they have application prospects in low-GI foods. The inhibition rate of α-amylase by highland barley β-glucan obtained by different extraction methods will also vary.

[0071] To this end, the present invention also tests the α-amylase inhibitory properties of highland barley β-glucan obtained from the optimal group of Example 3, the optimal group of Comparative Example 1 (including nanofiltration and alcohol precipitation) and Comparative Example 2. The test method refers to the method of Ma Yanli et al. (Ma Yanli, Rang Yifeng, Zhao Wei, Yang Ruijin. Study on the inhibitory properties of white kidney bean α-amylase inhibitor on α-amylase [J]. Food Industry Science and Technology, 2017, 38 (12): 109-112.) to determine the effect of highland barley β-glucan on the inhibitory properties of α-amylase. The specific operation is as follows:

[0072] 0.25 mL of α-amylase solution (1.5 U / mL) and 0.25 mL of appropriately diluted β-glucan sample solution (15 mg / mL) were added to 0.5 mL of 0.2 mol / L PBS (pH 6.9). The mixture was incubated at 37°C for 10 minutes. 0.5 mL of 1% (w / w) soluble starch solution was added and allowed to react for 10 minutes. 1 mL of DNS reagent was then added to terminate the reaction. The reaction solution was heated in a boiling water bath for 10 minutes and then quickly cooled to room temperature in an ice-water bath. 5 mL of pure water was then added, mixed thoroughly, and the absorbance was measured at 540 nm. During the measurement, a blank tube, a blank control tube, and an inhibition control tube were set up. No sample was added to the blank tube, no α-amylase solution or sample was added to the blank control tube, and no α-amylase solution was added to the inhibition control tube. Any volume shortfall was made up with PBS. The reaction system is shown in Table 1:

[0073] Table 1

[0074]

[0075] The inhibition rate (AR) of highland barley β-glucan on α-amylase was calculated according to formula (1):

[0076]

[0077] Where A1, A2, A3 and A4 are the absorbance values ​​of the blank tube, blank control tube, inhibition tube and inhibition control tube at 540 nm, respectively.

[0078] The test results are as follows Figure 5 As shown, the α-amylase inhibition rate of highland barley β-glucan corresponding to the optimal value group in Example 3 is the highest, indicating that compared with the existing method, the method of the present invention can improve the α-amylase inhibition rate of highland barley β-glucan.

[0079] In summary, the method for preparing highland barley β-glucan provided by the present invention not only overcomes the drawbacks of traditional alkaline or acidic methods for extracting β-glucan, such as high water consumption or ethanol consumption leading to high processing costs, but also greatly improves the extraction rate and lipophilicity of highland barley β-glucan. At the same time, compared with highland barley β-glucan prepared by other existing methods, the highland barley β-glucan prepared by the present invention has a significantly improved α-amylase inhibition rate, and has greater application potential in low-GI foods.

[0080] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention may be improved in only one or several aspects, without having to simultaneously solve all the technical problems listed in the prior art or background art. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as limiting the claim.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing highland barley β-glucan, characterized in that: Including alkaline extraction or acid extraction; The alkaline extraction comprises first mixing highland barley powder with a calcium hydroxide solution and performing heating extraction to obtain an alkaline extract, then adding citric acid to the alkaline extract to neutralize the solution to produce a precipitate, and filtering the solution to obtain an alkaline-soluble highland barley β-glucan extract; The acid extraction comprises mixing highland barley powder with citric acid and performing heating extraction to obtain an acid extract, then adding a calcium hydroxide solution to the acid extract to neutralize the solution to produce a precipitate, and filtering the solution to obtain an acid-soluble highland barley β-glucan extract; In the alkaline extraction, the ratio of the highland barley powder to the calcium hydroxide solution is 1 g: 15 mL to 30 mL; In the acid extraction, the ratio of the highland barley powder to the citric acid is 1 g: 15 mL to 25 mL.

2. The method for preparing highland barley β-glucan according to claim 1, wherein: After the alkaline extraction, the precipitate obtained in the alkaline extraction is mixed with water, and then citric acid is added and the pH of the system is adjusted to 2-4 before continuing heating extraction. Then, calcium hydroxide solution is added to generate precipitation, and the precipitation is filtered to obtain an acid-soluble highland barley beta-glucan extract.

3. The method for preparing highland barley β-glucan according to claim 1, wherein: After the acid extraction, the precipitate obtained in the acid extraction is added to a calcium hydroxide solution, and the pH of the system is adjusted to 9-10 before continuing the heating extraction. Then, citric acid is added to generate a precipitate, and the precipitate is filtered to obtain an alkali-soluble barley beta-glucan extract.

4. The method for preparing highland barley β-glucan according to claim 1, wherein: The calcium hydroxide solution is obtained by mixing Ca(OH)2 and water in a ratio of 1 g: 25 mL to 500 mL.

5. The method for preparing highland barley β-glucan according to claim 1, wherein: The heating extraction temperature range of the alkaline extraction and the acid extraction is 55° C. to 95° C.

6. The method for preparing highland barley β-glucan according to claim 1, wherein: The heating extraction time of the alkaline extraction and the acid extraction is in the range of 1 hour to 3 hours.

7. The method for preparing highland barley β-glucan according to claim 1, wherein: During the alkaline extraction process, the condition for neutralizing Ca(OH)2 with C6H8O6 is that the molar ratio of C6H8O6 to Ca(OH)2 is 2:1; During the acid extraction process, the condition for the neutralization of C6H8O6 by Ca(OH)2 is that the molar ratio of Ca(OH)2 to C6H8O6 is 1:

2.

8. The method for preparing highland barley β-glucan according to claim 1, wherein: The alkali-soluble highland barley beta-glucan extract and / or the acid-soluble highland barley beta-glucan extract are respectively concentrated under reduced pressure and dried, and then mixed to obtain a solid highland barley beta-glucan finished product.

9. A highland barley β-glucan, characterized in that: The highland barley β-glucan is prepared by the preparation method of any one of claims 1 to 8.

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