Preparation method of high-activity flaxseed powder

Abstract

The invention discloses a preparation method of high-activity flaxseed powder, which comprises the following steps: (1) detoxification treatment: mixing flaxseeds and water according to a mass ratio of 1: 4-1: 6, carrying out microwave treatment, washing with water, and drying; (2) pulping treatment: mixing and pulping the detoxified flaxseeds and water according to a mass ratio of 1: 3.5-1: 4.5, adjusting the solid content of the pulp to 12-14%, and then carrying out enzymolysis treatment; (3) emulsification treatment: adding soybean lecithin into the enzymolysis product, and shearing and emulsifying to obtain an emulsion; (4) homogenizing treatment: adopting two-stage homogenizing; and (5) performing spray drying to obtain the high-activity flaxseed powder. According to the preparation method disclosed by the invention, multiple steps of microwave detoxification, enzymolysis treatment, composite emulsification, secondary homogenization and the like are cooperated, so that cyanogenic glycoside is efficiently removed, meanwhile, the retention rate of alpha-linolenic acid and lignan is remarkably increased, and the product is endowed with excellent solubility, emulsification stability and brewing performance.

Description

Technical Field

[0001] This invention belongs to the field of health food and functional food raw material processing technology, and in particular relates to a method for preparing highly active flaxseed powder. Background Technology

[0002] Flaxseed is a traditional oilseed crop, rich in various nutrients and bioactive substances, among which alpha-linolenic acid (an omega-3 polyunsaturated fatty acid) and lignans (a type of phytoestrogen) are of particular interest. Alpha-linolenic acid has physiological functions such as anti-inflammation, lowering blood lipids, and promoting nervous system development, while lignans exhibit antioxidant, anti-tumor, and endocrine-regulating properties. Therefore, flaxseed products have broad application potential in health foods, special medical foods, dietary supplements, and general foods.

[0003] However, the processing and application of flaxseed faces several key technical challenges. First, flaxseed contains cyanogenic glycosides, which can decompose into hydrocyanic acid under certain conditions, posing a risk to food safety. Traditional detoxification methods, such as boiling, steam heat treatment, or organic solvent extraction, while effectively reducing cyanogenic glycoside content, involve high temperatures and long processing times. This can easily lead to the oxidation and deterioration of heat-sensitive unsaturated fatty acids and protein denaturation in flaxseed, resulting in severe loss of functional components and a significant reduction in the product's nutritional value.

[0004] Secondly, flaxseed powder produced by conventional mechanical grinding methods suffers from problems such as large particle size, poor solubility, easy sedimentation, and a rough texture, which seriously affect consumer acceptance and the product's application in liquid foods. Furthermore, due to its high fat content, flaxseed powder is prone to oil oxidation during storage, leading to rancidity and spoilage, and a short shelf life.

[0005] Some improvements have emerged in existing technologies. For example, low-temperature pressing is used to extract the oil first, followed by grinding the defatted meal. However, this process is cumbersome and results in a significant loss of fat-soluble active ingredients. Other studies have attempted to use enzymatic hydrolysis to degrade anti-nutritional factors or to utilize ultrafine grinding technology to improve powder fineness. However, these methods are often costly, or it is difficult to simultaneously achieve detoxification and retention of active ingredients, and they offer limited improvement in the emulsification stability and reconstitution properties of the final product.

[0006] Therefore, the current flaxseed deep processing industry urgently needs a novel solution that is highly integrated, easy to operate, moderately cost-effective, and can simultaneously achieve efficient detoxification, maximize the retention of functional components, and significantly improve product solubility and stability. This invention addresses these industry pain points by providing a method for preparing highly active flaxseed powder. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, a method for preparing highly active flaxseed powder is provided.

[0008] This invention is achieved through the following scheme:

[0009] A method for preparing highly active flaxseed powder, the method comprising the following steps:

[0010] (1) Detoxification treatment: Mix flaxseed with water at a mass ratio of 1:4 to 1:6, microwave, rinse with water and dry;

[0011] (2) Pulping treatment: Mix virus-free flax seeds and water at a mass ratio of 1:3.5 to 1:4.5 and pulverize. Adjust the solid content of the pulp to 12% to 14% by vacuum rotary evaporation, and then carry out enzymatic hydrolysis treatment.

[0012] (3) Emulsification treatment: Soybean lecithin was added to the enzymatic hydrolysate obtained in step (2), and the mixture was sheared and emulsified to obtain an emulsion;

[0013] (4) Homogenization: Two-stage homogenization is adopted, with the first stage homogenization pressure being 35-45 MPa and the second stage homogenization pressure being 18-22 MPa;

[0014] (5) Spray drying: control the inlet air temperature to 155-165℃ and the outlet air temperature to 72-78℃ to obtain highly active flaxseed powder.

[0015] In step (1), the microwave power of the microwave treatment is 450-550W, and the microwave treatment time is 2.5-3.5 minutes.

[0016] In step (2), the enzymatic hydrolysis treatment includes the following steps: adjusting the pH of the slurry obtained by vacuum rotary evaporation to 6.0-7.0, adding neutral protease, and enzymatically hydrolyzing at 45-55°C for 1-3 hours.

[0017] The amount of neutral protease added is 0.5% to 2% of the total mass of the slurry obtained by vacuum rotary evaporation.

[0018] In step (3), sucrose fatty acid esters and sodium alginate are also added to the enzymatic hydrolysis product.

[0019] The amount of sucrose fatty acid ester added is 0.5% to 1.5% of the total mass of the enzymatic hydrolysis product in step (2), and the amount of sodium alginate added is 0.2% to 0.8% of the total mass of the enzymatic hydrolysis product in step (2).

[0020] Before homogenization in step (4), maltodextrin and microcrystalline cellulose are added to the emulsion obtained in step (3).

[0021] The amount of maltodextrin added is 5% to 10% of the total mass of the emulsion, and the amount of microcrystalline cellulose added is 0.5% to 1.5% of the total mass of the emulsion.

[0022] In step (3), the amount of soybean lecithin added is 4% to 6% of the total mass of the enzymatic hydrolysate obtained in step (2).

[0023] In step (4), the specific parameters for shear emulsification are: shear emulsification for 2.5 to 3.5 minutes at a rotation speed of 8500 to 9500 r / min.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. This invention optimizes the preparation process of flaxseed powder, achieving technological synergy in multiple processing steps, thus producing a series of beneficial effects. In the detoxification stage, a combination of microwave treatment and water washing is employed. Utilizing the rapid penetration and selective heating characteristics of microwave energy, cyanogenic glycosides in flaxseed are effectively extracted and removed during the water washing process in a shorter treatment time and at a relatively low temperature. This method avoids the damage to heat-sensitive components such as unsaturated fatty acids and proteins in flaxseed caused by traditional high-temperature, long-term treatment, thus better preserving the natural active ingredients of the raw material.

[0026] 2. This invention introduces an enzymatic hydrolysis step after pulping. By adding neutral protease to specifically treat the pulp, the large molecules of flaxseed protein can be broken down into smaller peptides and amino acids. This significantly improves the solubility and digestibility of the final product, and reduces the interference of protein molecules on interfacial stability during subsequent emulsification, thus creating favorable conditions for the formation of a stable emulsion system.

[0027] 3. In the emulsification stage, this invention uses soybean lecithin as the main emulsifier. Its amphiphilic molecular structure effectively reduces the interfacial tension between oil and water. Simultaneously, with the synergistic effect of the enzymatic hydrolysis products, a finer and more stable oil droplet dispersion system is formed. After subsequent two-stage step pressure homogenization, the droplet size of this composite emulsion system is further homogenized, and the distribution range is significantly narrowed, thereby greatly improving the physical stability of the emulsion and laying a solid foundation for the subsequent spray drying preparation of powder products with good rehydration properties.

[0028] 4. The optimized design of spray drying process parameters also played a crucial role. By controlling appropriate inlet and outlet air temperatures, efficient evaporation of moisture was ensured while avoiding the oxidative damage of heat-sensitive components such as α-linolenic acid caused by excessively high temperatures. At the same time, the product powder maintained a porous and loose granular structure, which is conducive to the rapid dissolution and good dispersion of the powder.

[0029] 5. Significant synergistic enhancement effects exist among the various process steps of this invention. Microwave detoxification provides better substrate accessibility for subsequent enzymatic hydrolysis, which in turn creates more favorable interfacial conditions for emulsification and homogenization. The optimized emulsification and homogenization effect directly contributes to the final quality of the spray-dried product. This multi-step synergistic effect significantly improves the retention of active ingredients, solubility, and stability of the final highly active flaxseed powder, overcoming the limitations of traditional single-modification methods that often only focus on one aspect. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments:

[0031] A method for preparing highly active flaxseed powder, the method comprising the following steps:

[0032] (1) Detoxification treatment: Mix flaxseed with water at a mass ratio of 1:4 to 1:6, microwave, rinse with water and dry;

[0033] (2) Pulping treatment: Mix virus-free flax seeds and water at a mass ratio of 1:3.5 to 1:4.5 and pulverize. Adjust the solid content of the pulp to 12% to 14% by vacuum rotary evaporation, and then carry out enzymatic hydrolysis treatment.

[0034] (3) Emulsification treatment: Soybean lecithin was added to the enzymatic hydrolysate obtained in step (2), and the mixture was sheared and emulsified to obtain an emulsion;

[0035] (4) Homogenization: Two-stage homogenization is adopted, with the first stage homogenization pressure being 35-45 MPa and the second stage homogenization pressure being 18-22 MPa;

[0036] (5) Spray drying: control the inlet air temperature to 155-165℃ and the outlet air temperature to 72-78℃ to obtain highly active flaxseed powder.

[0037] In step (1), the microwave power of the microwave treatment is 450-550W, and the microwave treatment time is 2.5-3.5 minutes.

[0038] In step (2), the enzymatic hydrolysis treatment includes the following steps: adjusting the pH of the slurry obtained by vacuum rotary evaporation to 6.0-7.0, adding neutral protease, and enzymatically hydrolyzing at 45-55°C for 1-3 hours.

[0039] The amount of neutral protease added is 0.5% to 2% of the total mass of the slurry obtained by vacuum rotary evaporation.

[0040] In step (3), sucrose fatty acid esters and sodium alginate are also added to the enzymatic hydrolysis product.

[0041] The amount of sucrose fatty acid ester added is 0.5% to 1.5% of the total mass of the enzymatic hydrolysis product in step (2), and the amount of sodium alginate added is 0.2% to 0.8% of the total mass of the enzymatic hydrolysis product in step (2).

[0042] Before homogenization in step (4), maltodextrin and microcrystalline cellulose are added to the emulsion obtained in step (3).

[0043] The amount of maltodextrin added is 5% to 10% of the total mass of the emulsion, and the amount of microcrystalline cellulose added is 0.5% to 1.5% of the total mass of the emulsion.

[0044] In step (3), the amount of soybean lecithin added is 4% to 6% of the total mass of the enzymatic hydrolysate obtained in step (2).

[0045] In step (4), the specific parameters for shear emulsification are: shear emulsification for 2.5 to 3.5 minutes at a rotation speed of 8500 to 9500 r / min.

[0046] Through careful design and parameter optimization of each step, as well as the synergistic effect between steps, the preparation method yields a product that not only retains the original nutritional value of flaxseed, but also shows significant improvements in solubility, stability, and bioavailability, thus effectively solving a long-standing technical problem in the development of flaxseed powder products.

[0047] The technical solutions of the present invention are further illustrated below through examples and comparative examples, but the scope of protection of the present invention is not limited thereto.

[0048] Example 1

[0049] This embodiment provides a method for preparing highly active flaxseed powder. First, a detoxification process is performed. 100 parts of flaxseed are weighed and mixed with 600 parts of water, placed in a microwave oven, and processed at 550 watts for 2.5 minutes. After processing, the water is drained, and the flaxseed is rinsed three times with clean water, then dried at 75 degrees Celsius to obtain detoxified flaxseed. Next, a pulping process is performed. 100 parts of detoxified flaxseed are mixed with 350 parts of water and mechanically pulped to obtain a coarse pulp. The pulp is concentrated using a vacuum rotary evaporator at 65 degrees Celsius and a vacuum degree of -0.08 MPa to adjust the solids content to 12%. Subsequently, enzymatic hydrolysis is performed. The pH of the pulp is adjusted to 6.0 with food-grade sodium hydroxide solution, and 2% (by weight) of neutral protease is added. Enzymatic hydrolysis is carried out at 45 degrees Celsius for 3 hours. After enzymatic hydrolysis, emulsification was performed. Soybean lecithin (6% by mass of the total hydrolysate), sucrose fatty acid ester (1.5% by mass of the total hydrolysate), and sodium alginate (0.2% by mass of the total hydrolysate) were added to the emulsion. The mixture was sheared and emulsified at 8500 rpm for 3.5 minutes. Then, maltodextrin (10% by mass of the total emulsion) and microcrystalline cellulose (0.5% by mass of the emulsion) were added to the emulsion. After thorough mixing, homogenization was performed. The first homogenization pressure was 35 MPa, and the second homogenization pressure was 22 MPa. Finally, spray drying was carried out, controlling the inlet air temperature at 155°C and the outlet air temperature at 78°C, to obtain highly active flaxseed powder.

[0050] Example 2

[0051] This embodiment provides another method for preparing highly active flaxseed powder. First, a detoxification process is performed. 100 parts flaxseed are weighed and mixed with 400 parts water, placed in a microwave device, and treated at 450 watts for 3.5 minutes. After treatment, the water is drained, the flaxseed is rinsed twice with clean water, and then dried at 65 degrees Celsius to obtain detoxified flaxseed. Next, a pulping process is performed. 100 parts detoxified flaxseed are mixed with 450 parts water and mechanically pulped to obtain a coarse pulp. The pulp is concentrated using a vacuum rotary evaporator at 60 degrees Celsius and a vacuum degree of -0.09 MPa to adjust the solids content to 14%. Then, enzymatic hydrolysis is performed. The pH of the pulp is adjusted to 7.0 with food-grade hydrochloric acid solution, and 0.5% of the total mass of neutral protease is added. Enzymatic hydrolysis is carried out at 55 degrees Celsius for 1 hour. After enzymatic hydrolysis, emulsification was performed. 4% soybean lecithin, 0.5% sucrose fatty acid ester, and 0.8% sodium alginate were added to the hydrolysate. The mixture was sheared and emulsified at 9500 rpm for 2.5 minutes. Then, 5% maltodextrin and 1.5% microcrystalline cellulose were added to the emulsion. After thorough mixing, homogenization was performed. The first homogenization pressure was 45 MPa, and the second homogenization pressure was 18 MPa. Finally, spray drying was carried out, controlling the inlet air temperature at 165°C and the outlet air temperature at 72°C to obtain highly active flaxseed powder.

[0052] Example 3

[0053] This embodiment provides another method for preparing highly active flaxseed powder. First, a detoxification process is performed. 100 parts of flaxseed are weighed and mixed with 500 parts of water, placed in a microwave oven, and processed at 500 watts for 3 minutes. After processing, the water is drained, and the flaxseed is rinsed three times with clean water, then dried at 70 degrees Celsius to obtain detoxified flaxseed. Next, a pulping process is performed. 100 parts of detoxified flaxseed are mixed with 400 parts of water and mechanically pulped to obtain a coarse pulp. The pulp is concentrated using a vacuum rotary evaporator at 62 degrees Celsius and a vacuum degree of -0.085 MPa to adjust the solids content to 13%. Subsequently, enzymatic hydrolysis is performed. The pH of the pulp is adjusted to 6.5 with food-grade citric acid solution, and 1.5% (by weight) of neutral protease is added. Enzymatic hydrolysis is carried out at 50 degrees Celsius for 2 hours. After enzymatic hydrolysis, emulsification was performed by adding 5% soybean lecithin, 1.0% sucrose fatty acid ester, and 0.5% sodium alginate to the hydrolysate. The mixture was sheared and emulsified at 9000 rpm for 3 minutes. Then, 8% maltodextrin and 1.0% microcrystalline cellulose were added to the emulsion, and the mixture was homogenized. The first homogenization pressure was 40 MPa, and the second homogenization pressure was 20 MPa. Finally, spray drying was performed, controlling the inlet air temperature at 160°C and the outlet air temperature at 75°C to obtain highly active flaxseed powder.

[0054] Comparative Example 1

[0055] Comparative Example 1 is basically the same as Example 3, except that the enzymatic hydrolysis step is omitted and emulsification is performed directly after pulping and adjusting the solid content.

[0056] Comparative Example 2

[0057] Comparative Example 2 is basically the same as Example 3, except that the detoxification treatment uses the traditional boiling method, where flaxseed and water are mixed in a mass ratio of 1:6 and boiled for 30 minutes, then washed and dried.

[0058] Comparative Example 3

[0059] Comparative Example 3 is basically the same as Example 3, except that only soybean lecithin is added during the emulsification process, and sucrose fatty acid esters and sodium alginate are not added.

[0060] Comparative Example 4

[0061] Comparative Example 4 is basically the same as Example 3, except that the homogenization process uses single-stage homogenization at a pressure of 20 MPa.

[0062] Comparative Example 5

[0063] Comparative Example 5 is basically the same as Example 3, except that the inlet air temperature of the spray dryer is set to 180 degrees Celsius and the outlet air temperature is set to 85 degrees Celsius.

[0064] To evaluate the quality of the highly active flaxseed powder prepared according to this invention, multiple performance tests were conducted on the products obtained from the three examples and five comparative examples. The test indicators included cyanogenic glycoside residue, α-linolenic acid retention rate, lignan retention rate, dissolution time, emulsification stability index, and powder flowability. The test results are shown in Table 1.

[0065] Table 1 Analysis of Test Results

[0066] Sample number Cyanogenic glycoside residue (mg / kg) α-Linolenic acid retention percentage Percentage of lignan retention Dissolution time (seconds) Emulsion stability index Powder flowability millimeters per second Example 1 8.2 92.5 88.7 14 0.94 78 Example 2 7.8 91.8 87.9 13 0.93 76 Example 3 7.5 93.2 89.4 12 0.95 80 Comparative Example 1 7.6 90.3 86.2 22 0.87 72 Comparative Example 2 6.9 85.6 82.4 15 0.91 77 Comparative Example 3 7.4 92.8 88.9 18 0.89 79 Comparative Example 4 7.7 92.1 88.3 16 0.90 78 Comparative Example 5 7.3 87.5 84.6 13 0.92 75

[0067] The test results show that the products of all three examples exhibit excellent performance across all indicators. The residual amount of cyanogenic glycosides was below 10 mg / kg, far below the limit required by food safety standards, indicating that microwave detoxification treatment effectively removes toxic substances. The retention rates of α-linolenic acid and lignans were both around 90%, demonstrating the significant protective effect of the entire process system on heat-sensitive functional components. The dissolution time was less than 15 seconds, the emulsification stability index was higher than 0.93, and the powder had good flowability, indicating that the products possess excellent reconstitution properties and storage stability.

[0068] Comparative Example 1, by omitting the enzymatic hydrolysis step, failed to effectively degrade protein macromolecules, leading to prolonged product dissolution time and decreased emulsion stability. This confirms the crucial role of enzymatic hydrolysis in improving product solubility and stability. Comparative Example 2 used traditional boiling detoxification. While the detoxification effect was slightly better, the prolonged high-temperature treatment resulted in significant loss of heat-sensitive components such as α-linolenic acid and lignans, significantly reducing retention rates. This demonstrates the advantage of microwave detoxification in preserving active ingredients. Comparative Example 3 did not use a compound emulsifier. The single emulsifier system lacked stability, resulting in a decreased emulsion stability index, indicating the crucial synergistic effect of compound emulsifiers. Comparative Example 4 used single-stage homogenization, resulting in a wider droplet size distribution and lower system stability compared to two-stage homogenization, showcasing the superiority of two-stage stepped pressure homogenization. Comparative Example 5 used a higher drying temperature. Although it had little impact on solubility, the high temperature exacerbated the oxidation of unsaturated fatty acids, significantly reducing the retention rate of active ingredients. This confirms the importance of controlling drying temperature for protecting functional components.

[0069] In summary, this invention, through the optimized design and parameter control of a multi-step process, generates a significant synergistic effect among the various processes. The final product exhibits significant advantages in terms of safety, retention rate of functional components, and performance, effectively solving key technical challenges in the development of flaxseed powder products.

[0070] Although the technical solutions of the present invention have been described and enumerated in detail, it should be understood that modifications to the above embodiments or the adoption of equivalent alternatives are obvious to those skilled in the art. Such modifications or improvements made without departing from the spirit of the present invention are all within the scope of protection claimed by the present invention.

Claims

1. A method for preparing highly active flaxseed powder, characterized in that, The method includes the following steps: (1) Detoxification treatment: Mix flaxseed with water at a mass ratio of 1:4 to 1:6, microwave, rinse with water and dry; (2) Pulping treatment: Mix virus-free flax seeds and water at a mass ratio of 1:3.5 to 1:4.5 and pulverize. Adjust the solid content of the pulp to 12% to 14% by vacuum rotary evaporation, and then carry out enzymatic hydrolysis treatment. (3) Emulsification treatment: Soybean lecithin was added to the enzymatic hydrolysate obtained in step (2), and the mixture was sheared and emulsified to obtain an emulsion; (4) Homogenization: Two-stage homogenization is adopted, with the first stage homogenization pressure being 35-45 MPa and the second stage homogenization pressure being 18-22 MPa; (5) Spray drying: control the inlet air temperature to 155-165℃ and the outlet air temperature to 72-78℃ to obtain highly active flaxseed powder.

2. The method for preparing highly active flaxseed powder according to claim 1, characterized in that: In step (1), the microwave power of the microwave treatment is 450-550W, and the microwave treatment time is 2.5-3.5 minutes.

3. The method for preparing highly active flaxseed powder according to claim 1, characterized in that: In step (2), the enzymatic hydrolysis treatment includes the following steps: adjusting the pH of the slurry obtained by vacuum rotary evaporation to 6.0-7.0, adding neutral protease, and enzymatically hydrolyzing at 45-55°C for 1-3 hours.

4. The method for preparing highly active flaxseed powder according to claim 3, characterized in that: The amount of neutral protease added is 0.5% to 2% of the total mass of the slurry obtained by vacuum rotary evaporation.

5. The method for preparing highly active flaxseed powder according to claim 1, characterized in that: In step (3), sucrose fatty acid esters and sodium alginate are also added to the enzymatic hydrolysis product.

6. The method for preparing highly active flaxseed powder according to claim 5, characterized in that: The amount of sucrose fatty acid ester added is 0.5% to 1.5% of the total mass of the enzymatic hydrolysis product in step (2), and the amount of sodium alginate added is 0.2% to 0.8% of the total mass of the enzymatic hydrolysis product in step (2).

7. The method for preparing highly active flaxseed powder according to claim 5, characterized in that: Before homogenization in step (4), maltodextrin and microcrystalline cellulose are added to the emulsion obtained in step (3).

8. The method for preparing highly active flaxseed powder according to claim 7, characterized in that: The amount of maltodextrin added is 5% to 10% of the total mass of the emulsion, and the amount of microcrystalline cellulose added is 0.5% to 1.5% of the total mass of the emulsion.

9. The method for preparing highly active flaxseed powder according to claim 1, characterized in that: In step (3), the amount of soybean lecithin added is 4% to 6% of the total mass of the enzymatic hydrolysate obtained in step (2).

10. The method for preparing highly active flaxseed powder according to claim 1, characterized in that: In step (4), the specific parameters for shear emulsification are: shear emulsification for 2.5 to 3.5 minutes at a rotation speed of 8500 to 9500 r / min.