Microalgae milk rich in DHA and EPA and preparation method thereof

Abstract

The invention relates to microalgae milk rich in DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) and a preparation method thereof, microalgae powder rich in DHA and EPA is used as a raw material, the microalgae powder and water are uniformly stirred and mixed and then soaked to obtain algae liquid, algae are crushed through shearing, homogenizing and other steps, the algae liquid is homogenized, and finally the microalgae milk is obtained. According to the prepared microalgae milk, the microalgae powder containing DHA and EPA serves as the raw material, polysaccharide, protein and grease in microalgae are utilized to form an emulsification system, other components are not added, the preparation method is simple, large-scale production can be achieved, and the microalgae milk contains polyunsaturated fatty acid which cannot be synthesized by human bodies but is necessary; the preparation of the microalgae milk is beneficial to high-value utilization of microalgae.

Description

Technical Field

[0001] The present application belongs to the field of biotechnology, and specifically relates to a microalgae milk rich in DHA and EPA and a preparation method thereof. Background Art

[0002] Microalgae are rich in proteins, lipids, polysaccharides, vitamins, polyunsaturated fatty acids and other bioactive substances. They are widely used in food, feed, health products, biofuels and other fields. At present, many microalgae have been approved by the National Health Commission as new food raw materials, such as Chlorella pyrenoidosa, Dunaliella salina, Euglena, Nannochloropsis chlororaphis, Schizochytrium, Haematococcus pluvialis, and Crypthecodinium cohnii. Microalgae are a natural source of omega-3 fatty acids, including DHA and EPA, which are important nutrients indispensable to the human body. Although DHA and EPA can be converted from linolenic acid during metabolism in the body, the conversion rate is very slow and the amount generated is very low, which is far from meeting the needs of the human body. Therefore, they must be supplemented directly from food. DHA is an important component of brain cell membranes, participates in the formation and development of brain cells, can resist oxidation, anti-aging, improve blood circulation, reduce serum total cholesterol and low-density lipoprotein cholesterol, increase high-density lipoprotein cholesterol, and can treat hyperlipidemia, atherosclerosis, etc. EPA has the functions of reducing cholesterol and triglyceride content, promoting the metabolism of saturated fatty acids in the body, thereby reducing blood viscosity, improving blood circulation, improving tissue oxygen supply and eliminating fatigue, preventing fat deposition in blood vessel walls, preventing the formation and development of atherosclerosis, and preventing cardiovascular and cerebrovascular diseases such as cerebral thrombosis, cerebral hemorrhage, and hypertension. Therefore, microalgae such as Nannochloropsis and Schizochytrium are potential new food raw materials for the development of DHA and EPA.

[0003] Plant milk has developed rapidly in my country in recent years. It is an emulsion with plant protein as the main raw material, which is made from plant raw materials and their products containing a certain amount of protein. It is popular among consumers for its characteristics of no or low cholesterol content, rich protein and amino acids, moderate unsaturated fatty acids, and relatively complete nutrients. At present, most of the plant proteins used in plant milk products on the market are from grains or nuts, and microalgae are a new generation of plant protein and unsaturated fatty acid oil source. We use polysaccharides, proteins, and lipids in microalgae to form an emulsification system to prepare microalgae milk rich in DHA and EPA as a dairy substitute, which is in line with the popular trend of plant-based and sustainable, and has great development potential.

[0004] Chinese patent CN113040220A discloses a functional microalgae protein milk and a preparation method thereof, which is obtained by enzymatically treating microalgae filtrate, adding food additives, lactic acid bacteria, edible flavors, white sugar and purified water for mixing and stirring. The present invention does not add any other nutrients, and through a specific process, the oil and protein in the microalgae are released, and the special flavor of the algae is obtained.

[0005] Chinese patent CN113480425A discloses a process for extracting DHA and EPA from microalgae, comprising the following steps: (1) microalgae culture; (2) raw material crushing; (3) enzymatic hydrolysis; (4) sedimentation separation; (5) extraction; (6) separation and purification. It is a preparation method combining enzymatic hydrolysis and physical extraction. The difference from the present invention is that the present invention directly extracts and releases the oil and protein in the microalgae at the same time, and does not require a purification step, which is more conducive to the development of functional foods. Summary of the invention

[0006] The purpose of the present invention is to provide a microalgae milk rich in DHA and EPA and a preparation method thereof, which does not require the addition of other ingredients and has a simple preparation method, and contains unsaturated fatty acids DHA and EPA that are essential to the human body.

[0007] The purpose of the present invention is achieved through the following technical solutions.

[0008] A microalgae milk rich in DHA and EPA and a preparation method thereof, wherein microalgae powder and water are stirred and mixed evenly, and then soaked to obtain algae liquid, and then the algae bodies are crushed and the algae liquid is homogenized through shearing, homogenization and other steps, and finally the microalgae milk is obtained, which specifically comprises the following steps: (1) Dispersing microalgae powder in distilled water, adding an appropriate amount of sodium bicarbonate to adjust the pH to neutral, stirring and mixing evenly, and then soaking to obtain algae liquid; (2) subjecting the algae liquid prepared in (1) to high-speed shearing to complete pre-homogenization; (3) The algae liquid pre-homogenized in (2) is broken to obtain Nannochloropsis algae milk.

[0009] Furthermore, the microalgae described in step (1) include microalgae listed as new food raw materials, such as Chlorella pyrenoidosa, Dunaliella salina, Euglena, Nannochloropsis sphaeroides, Schizochytrium, Haematococcus pluvialis, and Crypthecodinium cohnii.

[0010] Furthermore, in step (1), the content of the microalgae powder is 5-20wt%, and the content of water added is 80-95%.

[0011] Furthermore, in step (1), the microalgae oil content is 15%-60%, and the protein content is 20%-60%.

[0012] Furthermore, in step (1), the soaking time is 0-24 h and the temperature is 4°C.

[0013] Furthermore, in step (2), the high-speed shearing speed is 6000-15000 rpm, and the time is 10 min.

[0014] Furthermore, the crushing method in step (3) is ultrasonic crushing, ball milling crushing, enzymatic crushing, repeated freeze-thaw crushing, high-pressure homogenization crushing, and high-pressure microfluidization homogenization crushing.

[0015] Furthermore, the ultrasonic crushing power in step (3) is 200-650 W, and the time is 15-60 min; the ball milling speed is 300-450 rpm, and the time is 30min-60 min; the enzymatic hydrolysis temperature is 50°C, the pH is 5.0, 1% laccase is added for enzymatic hydrolysis for 4-8 h, and then 1% cellulase and 1% mannanase are added for enzymatic hydrolysis for 4-8 h; the number of repeated freeze-thaw crushing is 2-5 times, the freezing temperature is -20 to -80°C, each freezing is 6-12 h, the melting temperature is 40-60°C, and each melting time is 5-10 min; the high-pressure homogenization pressure is 80-200 MPa, and the homogenization is circulated 3-10 times; the high-pressure microfluidization homogenization pressure is 10000-30000 psi, and the homogenization is circulated 2-5 times.

[0016] The microalgae milk is prepared by the above preparation method. The microalgae milk is stable, rich in various biologically active substances such as protein, lipid, polysaccharide, vitamin and polyunsaturated fatty acid, and its source is microalgae, which has not been transmitted through the food chain, is more natural and safe, and the DHA and EPA contained can supplement the unsaturated fatty acids necessary for the human body. The present invention uses microalgae powder containing DHA and EPA as raw materials, uses polysaccharides, proteins and oils in microalgae to form an emulsified system, does not add other ingredients, and has a simple preparation method, which can achieve large-scale production and preparation.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The microalgae used in the present invention have not been transmitted through the food chain and are more natural and safe. They can be used as a source of DHA and EPA to supplement essential fatty acids for the human body, which is in line with sustainable development.

[0018] (2) The present invention utilizes microalgae with high oil and protein content, which are crushed to release microalgae polysaccharides, proteins and oils. The algae liquid can form a stable emulsified system after homogenization to obtain microalgae milk.

[0019] (3) The present invention only needs to crush and homogenize the algae powder solution to prepare microalgae milk, without adding other ingredients. The preparation method is simple and easy to prepare on a large scale. The preparation process does not include any centrifugation or filtration steps, and the functional nutrients in the raw materials are retained to the greatest extent. It can be used as a new type of plant protein beverage to replace traditional dairy products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the particle size distribution diagram of the microalgae milk of Example 1.

[0021] Figure 2 This is a picture of oil droplets stained with microalgae milk in Example 1. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto. For process parameters that are not particularly well-known, reference can be made to conventional techniques.

[0023] Example 1 This embodiment provides a preparation of microalgae milk, and the specific steps are as follows: (1) Weigh 10 g of Nannochloropsis algae powder into a beaker, pour in 90 mL of distilled water, add appropriate amount of sodium bicarbonate to adjust the pH to 7.5, place on a magnetic stirrer to stir evenly, and soak in a 4°C refrigerator for 12 h.

[0024] (2) Use a high-speed shearing machine to perform preliminary shearing and homogenization on the soaked Nannochloropsis algae liquid at a speed of 12000 rpm and a homogenization time of 10 min to obtain a pre-homogenized algae liquid.

[0025] (3) The pre-homogenized Chlorella algae liquid was homogenized by breaking the wall of the liquid through a high-pressure microfluidizer at a pressure of 30,000 psi and cyclically homogenized for 5 times to obtain stable microalgae milk.

[0026] The microalgae milk prepared in Example 1 is stable and rich in various bioactive substances such as protein, lipid, polysaccharide, vitamin and polyunsaturated fatty acid, and can especially supplement EPA which is essential for the human body.

[0027] Example 2 The preparation of microalgae milk, the specific steps are as follows: (1) Weigh 10 g of Nannochloropsis algae powder into a beaker, pour in 90 mL of distilled water, add appropriate amount of sodium bicarbonate to adjust the pH to 7.5, place on a magnetic stirrer to stir evenly, and soak in a 4°C refrigerator for 12 h.

[0028] (2) Use a high-speed shearing machine to perform preliminary shearing and homogenization on the soaked Nannochloropsis algae liquid at a speed of 12000 rpm and a homogenization time of 10 min to obtain a pre-homogenized algae liquid.

[0029] (3) The pre-homogenized Chlorella algae liquid was homogenized by breaking the cell wall using an ultrasonic cell disruptor. The ultrasonic power was 400 W, the ultrasonic power was 2 s, the interval was 2 s, and the ultrasonic time was 60 min. Thus, stable microalgae milk was obtained.

[0030] The microalgae milk prepared in Example 2 is stable and rich in various bioactive substances such as protein, lipid, polysaccharide, vitamin and polyunsaturated fatty acid, and can especially supplement EPA which is essential for the human body.

[0031] Example 3 The preparation of microalgae milk, the specific steps are as follows: (1) Weigh 10 g of Nannochloropsis algae powder into a beaker, pour in 90 mL of distilled water, add appropriate amount of sodium bicarbonate to adjust the pH to 7.5, place on a magnetic stirrer to stir evenly, and soak in a 4°C refrigerator for 12 h.

[0032] (2) The soaked Nannochloropsis algae liquid was preliminarily sheared and homogenized using a high-speed shearing machine at a speed of 12,000 rpm for 10 min to obtain a pre-homogenized algae liquid.

[0033] (3) The pre-homogenized Chlorella algae liquid was crushed by ball milling at a speed of 400 rpm for 60 min to obtain stable microalgae milk.

[0034] The microalgae milk prepared in Example 3 is stable and rich in various bioactive substances such as protein, lipid, polysaccharide, vitamin and polyunsaturated fatty acid, and can especially supplement EPA which is essential for the human body.

[0035] Example 4 The preparation of microalgae milk, the specific steps are as follows: (1) Weigh 10 g of Nannochloropsis algae powder into a beaker, pour in 90 mL of distilled water, add appropriate amount of sodium bicarbonate to adjust the pH to 7.5, place on a magnetic stirrer to stir evenly, and soak in a 4°C refrigerator for 12 h.

[0036] (2) Use a high-speed shearing machine to perform preliminary shearing and homogenization on the soaked Nannochloropsis algae liquid at a speed of 12000 rpm and a homogenization time of 10 min to obtain a pre-homogenized algae liquid.

[0037] (3) The pre-homogenized Chlorella algae liquid was broken by enzymatic hydrolysis at a temperature of 50°C and a pH of 5.0. 1% laccase was added for 4 h, and then 1% cellulase and 1% mannanase were added for 4 h to obtain stable microalgae milk.

[0038] The microalgae milk prepared in Example 4 is stable and rich in various bioactive substances such as protein, lipid, polysaccharide, vitamin and polyunsaturated fatty acid, and can especially supplement EPA which is essential for the human body.

[0039] The results of the determination of the protein, oil, EPA content and release rate of the microalgae milk prepared in Examples 1-5 are as follows: Element Protein content (g / 100mL) Oil content (g / 100mL) EPA content (g / 100mL) Example 1 2.51 1.52 0.27 Example 2 1.31 0.83 0.14 Example 3 1.4 0.8 0.11 Example 4 1.7 0.95 0.17 The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A microalgae milk, rich in DHA and EPA, prepared from microalgae without adding other ingredients.

2. A method for preparing microalgae milk rich in DHA and EPA, characterized in that: The steps include: (1) Dispersing microalgae powder in distilled water, stirring and mixing evenly, and then soaking to obtain algae liquid; (2) subjecting the algae liquid prepared in (1) to high-speed shearing to complete pre-homogenization; (3) The algae liquid pre-homogenized in (2) is broken to obtain microalgae milk.

3. The preparation method according to claim 2, characterized in that: In step (1), the microalgae are selected from one or more of the following microalgae: Chlorella pyrenoidosa, Dunaliella salina, Euglena, Nannochloropsis sphaeroides, Schizochytrium, Haematococcus pluvialis, and Crypthecodinium cohnii.

4. The preparation method according to claim 2, characterized in that: In step (1), the content of the microalgae powder is 5-20 wt %, and the content of water added is 80-95 wt %.

5. The preparation method according to claim 2, characterized in that: In step (1), the microalgae oil content is 15%-60%, and the protein content is 20%-60%.

6. The preparation method according to claim 2, characterized in that: In step (1), the soaking time is 0-24 h and the temperature is 4°C.

7. The preparation method according to claim 2, characterized in that: In step (2), the high-speed shearing speed is 6000-15000 rpm and the time is 10 min.

8. The preparation method according to claim 2, characterized in that: In step (3), the crushing method is selected from one of ultrasonic crushing, ball milling crushing, enzymatic crushing, repeated freeze-thaw crushing, high-pressure homogenization crushing, and high-pressure microfluidization homogenization crushing.

9. The preparation method according to claim 8, characterized in that: In step (3), the crushing method is high-pressure microfluidic homogenization crushing.

10. The preparation method according to claim 8, characterized in that: The ultrasonic crushing power is 200-650 W, and the time is 15-60 min; the ball milling speed is 300-450 rpm, and the time is 30min-60 min; the enzymatic hydrolysis temperature is 50°C, the pH is 5.0, 1% laccase is added for enzymatic hydrolysis for 4-8 h, and then 1% cellulase and 1% mannanase are added for enzymatic hydrolysis for 4-8 h; the number of repeated freeze-thaw crushing is 3-5 times, the freezing temperature is -20 to -80°C, each freezing is 6-12 h, the melting temperature is 40-60°C, and each melting time is 5-10 min; the high-pressure homogenization pressure is 80-200 MPa, and the cycle homogenization is 3-10 times; the high-pressure microjet homogenization pressure is 10000-30000 psi, and the cycle homogenization is 2-5 times.

11. Microalgae milk prepared by the preparation method according to any one of claims 2 to 10.

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