CN111748478A - A kind of microalgae wall-breaking processing method and its application - Google Patents

Abstract

The invention relates to a microalgae wall-breaking processing method. The microalgae wall-breaking processing method comprises the following steps: subjecting microalgae with a humidity of 25-75% to screw extrusion treatment, and then drying and pulverizing the extruded materials. Got broken wall microalgae powder. The microalgae wall-breaking processing method involved in the invention has high wall-breaking rate, high speed, low cost and low energy consumption; for microalgae with high protein content, such as Chlorella pyrenoidosa, after being processed, the protein dissolution rate is significantly improved, The highest can reach 92%, and the high-level structure of the protein is fully dissociated, making the protein more easily absorbed by the human body; for microalgae with high oil content, such as Chlorella vulgaris, after treatment, the oil dissolution rate is significantly improved, and the highest can reach 92% .

Description

A kind of microalgae wall-breaking processing method and its application

technical field

The invention belongs to the technical field of microalgae wall breaking, and in particular relates to a microalgae wall breaking processing method and application thereof.

Background technique

Microalgae was born more than 2 billion years ago and is one of the earliest life on earth. Microalgae on earth are ubiquitous and exist in oceans, lakes, land, deserts, and even high-altitude dust. Microalgae are the source of oxygen on the earth. The main contributor is the main primary producer of biomass on Earth. Microalgae such as Chlorella, Spirulina, etc. contain many edible high-value substances, such as polyunsaturated fatty acids, proteins, carotenoids, etc.

However, many microalgae have cell walls, such as Chlorella, Spirulina, and especially Chlorella, which have thick cell walls and cannot be digested after direct consumption. Therefore, as a food raw material, microalgae with cell walls need to undergo wall-breaking treatment to ensure that the human body can obtain the functional components therein. At present, the more mainstream methods of wall breaking include grinding method, high pressure homogenization method, ultrasonic method, repeated freeze-thaw method, enzymatic hydrolysis method, cavitation method, etc., which have limited effects on plant materials and microorganisms.

CN109609255A discloses a method for extracting microalgae oil by catalyzing the wall of biological enzyme, including four steps: microalgae culture centrifugal screening, protease treatment and boiling, ultrasonic treatment after compound enzyme treatment, and distillation extraction; The temperature of the solution maximizes the activity of the enzyme and reduces the amount of enzyme used. Finally, through a short ultrasonic treatment, the decomposition of the entire microalgae cells is accelerated, and the decomposition products are also separated from the oil on the microalgae, which is convenient for subsequent oil extraction. .

CN101817738A discloses a method for breaking the walls of algae and fungal cells and extracting DHA, an intracellular oil product, by using a physical method without the assistance of any organic solvent and chemical drugs. The microalgae or fungal fermentation broth after fermentation is separated and collected by the separation system, and the pH of the bacterial slurry is adjusted to 2.0-4.0 with acid, and then the temperature of the bacterial slurry is controlled at 10-20 °C. Homogeneous wall breaking; adding water to the bacteria mud after wall breaking, stirring, and separating the material and liquid through a three-phase separator to obtain DHA oil.

CN102051330A discloses a method for rapidly crushing microalgae cells. The microalgae to be crushed are mixed with liquid nitrogen for 0.1-1h, and then mechanically ground and crushed to obtain cell-broken microalgae, which are used for oil extraction after being illuminated for 0.5-2h. .

However, the above-mentioned wall breaking technology has the following drawbacks: complex equipment and high cost; too high energy consumption, too much waste water discharge; too low efficiency, not suitable for industrial production, etc. The microalgae wall-breaking processing method with low energy consumption and suitable for industrial production is very meaningful.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the purpose of the present invention is to provide a microalgae wall-breaking processing method and application thereof.

In order to achieve this object of the invention, the present invention adopts the following technical solutions:

In one aspect, the present invention provides a microalgae wall-breaking processing method, the microalgae wall-breaking processing method comprises: subjecting microalgae with a humidity of 25-75% to screw extrusion treatment, and drying the extruded material, Pulverize to obtain broken-wall microalgae powder.

The humidity of the microalgae can be 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or 75%, etc., any specific point within the above-mentioned numerical range Values can be selected, and will not be repeated here.

The screw extrusion treatment is performed by a single-screw extruder or a twin-screw extruder. There is a heating device on the outside of the barrel of the extruder to heat up the material in the barrel.

The microalgae wall-breaking processing method involved in the present invention has high wall-breaking rate, high speed and low cost. Because the humidity of the microalgae needs to be controlled within the range of 25-75%, the microalgae need not be completely dried after being collected and cleaned, that is, The wall-breaking treatment can be performed by extrusion, which greatly saves energy; and the invention creatively finds that controlling the humidity of the microalgae within the above range can better improve the wall-breaking rate of the microalgae. For microalgae with high protein content, such as protein cores After the chlorella is treated, its protein dissolution rate is significantly improved, up to 92%, and the high-level protein structure is fully dissociated, making the protein more easily absorbed by the human body; for microalgae with high oil content, such as Chlorella vulgaris, after treatment After that, the oil dissolution rate is significantly improved, and the highest can reach 92%.

Preferably, the humidity of the microalgae is 55-65%. Controlling the humidity of the microalgae within the range of 55-65% can significantly improve the wall-breaking rate of the microalgae.

Preferably, the starting temperature T ₀ of the screw extrusion process is 80-130°C, such as 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C ℃ or 130 ℃, etc., any specific point value within the above-mentioned numerical range can be selected, which will not be repeated here.

The starting temperature T ₀ of the screw extrusion process involved in the present invention is specifically selected to be in the range of 80-130 ° C, because if the temperature is too high, the back end will be heated and smeared, and if the temperature is too low, the preheating will be insufficient, and the broken Low wall rate.

Preferably, the starting temperature T ₀ of the screw extrusion process is 85-125°C.

Preferably, the end temperature T1 _of the screw extrusion process is 130-220°C, such as 130°C, 140°C, 145°C, 150°C, 160°C, 170°C, 180°C, 190°C, 195°C, 200°C , 210°C or 220°C, etc., any specific point value within the above-mentioned numerical range can be selected, and will not be repeated here.

The end temperature T1 _of the screw extrusion process involved in the present invention is specifically selected to be in the range of 130-220°C, because if the temperature is too high, slushy or puffing will occur, and if the temperature is too low, the heating will be insufficient and the wall breaking rate will be low.

Preferably, the end temperature T1 _of the screw extrusion process is 140-195°C.

Preferably, the total duration _t1 of the screw extrusion treatment is 10-200s, such as 10s, 20s, 50s, 80s, 100s, 120s, 150s, 180s or 200s, etc. Any specific point value within the above numerical range can be used The choice will not be repeated here.

The total duration t ₁ of the screw extrusion treatment is specifically selected to be in the range of 10-200 s, because if the treatment time is too long, the algal flour will be clumped, nutrient elements will be destroyed, and the odor of oil will be oxidized. If the treatment time is too short, the heating will be insufficient. , the wall breaking rate is low.

Preferably, the total duration _t1 of the screw extrusion process is 20-150s.

As a preferred technical solution of the present invention, the microalgae wall-breaking processing method comprises the following steps:

The microalgae with a humidity of 25-75% are subjected to screw extrusion treatment, the initial temperature T ₀ of the screw extrusion treatment is 80-130 ° C, the end temperature T ₁ of the screw extrusion treatment is 130-220 ° C, and the screw extrusion treatment is performed. The total processing time _t1 is 10-200s; the extruded material is then dried to reduce the humidity to below 10%, and pulverized to obtain broken-wall microalgae powder.

On the other hand, the present invention provides the application of the above-mentioned microalgae wall-breaking processing method in the preparation of microalgae food.

Compared with the prior art, the present invention has the following beneficial effects:

The microalgae wall-breaking processing method involved in the present invention has high wall-breaking rate, high speed and low cost. Because the humidity of the microalgae needs to be controlled within the range of 25-75%, the microalgae need not be completely dried after being collected and cleaned, that is, The wall-breaking treatment can be performed by extrusion, which greatly saves energy; and the invention creatively finds that controlling the humidity of the microalgae within the above range can better improve the wall-breaking rate of the microalgae. For microalgae with high protein content, such as protein cores After the chlorella is treated, its protein dissolution rate is significantly improved, up to 92%, and the high-level protein structure is fully dissociated, making the protein more easily absorbed by the human body; for microalgae with high oil content, such as Chlorella vulgaris, after treatment After that, the oil dissolution rate is significantly improved, and the highest can reach 92%.

Description of drawings

FIG. 1 is a polyacrylamide gel electrophoresis image of the wall-broken Chlorella nucleatum powder prepared in Example 1. FIG.

Detailed ways

The technical solutions of the present invention are further described below through specific embodiments. It should be understood by those skilled in the art that the embodiments are only for helping the understanding of the present invention, and should not be regarded as a specific limitation of the present invention.

Example 1

The present embodiment provides a wall-breaking processing method of Chlorella pyrenoidosa, and the method is as follows:

Chlorella pyrenoidosa was concentrated to a humidity of 65%, and then entered into a twin-screw extruder for screw extrusion treatment, the rotational speed was 90 rpm, the initial temperature T ₀ was set to 115 ° C, and the end temperature T ₁ was set to 165 ° C , the total time t ₁ of the screw extrusion treatment is 100s, and its specific heating mode is: the first stage is heated from 115 °C to 130 °C at a constant speed for 20s, and the second stage is heated from 130 °C to 165 °C at a constant speed for 80s; extrusion; The latter material is then dried with hot air to reduce the humidity to 5% and pulverized to obtain the broken-wall Chlorella pyrenoidosa powder.

Example 2

The present embodiment provides a wall-breaking processing method of Chlorella pyrenoidosa, and the method is as follows:

Chlorella pyrenoidosa was concentrated to a humidity of 55%, and then entered into a single-screw extruder for screw extrusion treatment with a rotating speed of 90 rpm, an initial temperature T ₀ set to 125 ° C, and an end temperature T ₁ set to 160 ° C , the total time t ₁ of the screw extrusion treatment is 65s, and its specific heating mode is: the first stage is heated from 125 °C to 130 °C at a constant speed for 15s, the second stage is heated from 130 °C to 150 °C at a constant speed, the time is 20s, and the third stage The temperature is increased from 150°C to 170°C at a constant speed for 20s, and the four-stage cooling is from 170°C to 160°C at a constant speed for 10s. The extruded material is then dried with hot air to reduce the humidity to 5%, and then crushed to break the wall. Chlorella pyrenoidosa powder.

Example 3

This embodiment provides a method for breaking the wall of Chlorella pyrenoidosa. The difference between the method and Example 1 is that the humidity of Chlorella pyrenoidosa is concentrated to 75%, and other conditions are kept unchanged. Change.

Example 4

This embodiment provides a method for breaking the wall of Chlorella pyrenoidosa. The difference between the method and Example 1 is that the humidity of Chlorella pyrenoidosa is concentrated to 45%, and other conditions are kept unchanged. Change.

Example 5

This embodiment provides a method for breaking the wall of Chlorella pyrenoidosa. The difference between the method and Example 1 is that the humidity of Chlorella pyrenoidosa is concentrated to 25%, and other conditions are kept unchanged. Change.

Example 6

The present embodiment provides a wall-breaking processing method of Chlorella vulgaris, the method is as follows:

Chlorella vulgaris was concentrated to a humidity of 55%, then entered into a twin-screw extruder for screw extrusion treatment, the rotational speed was 90 rpm, the initial temperature T ₀ was set to 120 ℃, and the end temperature T ₁ was set to 190 ℃, The total time t ₁ of the screw extrusion treatment is 110s, and its specific heating mode is: the first stage is heated from 120 °C to 150 °C at a constant speed for 60s, and the second stage is heated from 150 °C to 190 °C at a constant speed for 50s; after extrusion The obtained material is then dried with hot air to reduce the humidity to 5%, and crushed to obtain the broken wall common chlorella powder.

Example 7

This embodiment provides a method for breaking the wall of Chlorella vulgaris. The difference between the method and Example 9 is that the humidity of Chlorella vulgaris is concentrated to 40%, and other conditions remain unchanged.

Example 8

The present embodiment provides a method for breaking the wall of Chlorella vulgaris. The difference between the method and Example 9 is that the humidity of Chlorella vulgaris is concentrated to 70%, and other conditions remain unchanged.

Comparative Example 1

This comparative example provides a method for breaking the wall of Chlorella pyrenoidosa. The difference between the method and Example 1 is that the humidity of Chlorella pyrenoidosa is concentrated to 85%, and other conditions are kept unchanged. Change.

Comparative Example 2

This comparative example provides a method for breaking the wall of Chlorella pyrenoidosa. The difference between the method and Example 1 is that the humidity of Chlorella pyrenoidosa is concentrated to 15%, and other conditions are kept unchanged. Change.

Evaluation test:

(1) Evaluation of the dissolution rate of water-soluble protein:

The dissolution rate of water-soluble protein was used to evaluate the wall-breaking rate of the methods described in Examples 1-5 and Comparative Examples 1-2, and the BCA colorimetric method was used to measure it. ²⁺ is reduced to Cu ⁺ , and the working reagent changes from the original apple green to a purple complex, and its light absorption intensity at 562 nm is proportional to the protein concentration. Using the kit operation, first prepare the standard protein solution, make the standard curve, and calculate the protein concentration of the sample to be tested according to the regression equation of the standard curve.

Take a small amount of Chlorella pyrenoidosa with a humidity of 5%, fully grind the broken wall with a mortar, weigh 2 g of broken wall algae powder, add 20 mL of distilled water, shake for 1 min, stand for 10 min, repeat three times. After centrifugation at 5000rpm for 15min, the supernatant was taken, and the protein content was determined as A ₀ % according to the BCA method. 2 g of the wall-breaking protein Chlorella nucleatum powder obtained in Examples 1-8 was taken again, water-soluble protein was extracted according to the above steps, the supernatant was taken, and the protein content was determined according to the BCA method to be A ₁ %. The wall breaking rate Y can be calculated by the following formula: Y=A ₁ ×100%/A ₀ . The results are shown in Table 1:

Table 1

group Wall breaking rate Example 1 89% Example 2 92% Example 3 62% Example 4 69% Example 5 44% Comparative Example 1 33% Comparative Example 2 38%

It can be seen from the results in Table 1: the microalgae wall-breaking processing method involved in the present invention has a high wall-breaking rate, high speed and low cost, and the microalgae does not need to be completely dried after being harvested and cleaned, and the wall-breaking treatment can be carried out by extrusion, which greatly saves energy; compared with the comparative example, the present invention controls the humidity of the microalgae within the range of 25-75%, which can better improve the wall-breaking rate of the microalgae. The highest can reach 92%.

(2) Evaluation of grease precipitation rate:

The wall-breaking rate of the method described in Example 6-8 was evaluated by the oil precipitation rate, and 2 g (calculated on a dry basis) of the broken-wall Chlorella vulgaris powder obtained in Example 6-8 was weighed, and 12 mL was added to a centrifuge tube. n-hexane, shake for 30s, stand for 10min, repeat three times. Then centrifuge at 8000rpm for 10min, suck out the upper organic layer with a pipette, and transfer it to a new centrifuge tube (pre-dried and accurately weighed). The n-hexane was then removed with a nitrogen blower and then weighed. Then weigh 2 g of common chlorella powder with a humidity of 5% (calculated on a dry basis), fully grind the wall with a mortar, extract oil and fat according to the above steps, and finally weigh. Oil and fat precipitation rate = sample oil weight × 100% / Prototheca flour oil weight. The results are shown in Table 2:

Table 2

group Wall breaking rate Example 6 92% Example 7 65% Example 8 84%

It can be seen from the results in Table 2: the microalgae wall-breaking processing method involved in the present invention has a high wall-breaking rate to the common chlorella powder, and after treatment, its oil and fat precipitation rate is significantly improved, and the highest can reach 92%; The initial humidity has a significant effect on the final oil precipitation rate.

(3) Evaluation of the dissociation effect of protein higher-order structure:

Take the wall-broken Chlorella pyrenoidosa powder prepared in Example 1, and use polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis to characterize the influence on the distribution of protein molecules after extrusion and breaking the wall. The humidity is 5%. The original powder of Chlorella pyrenoidosa was used as a control, and the results are shown in Figure 1. It can be seen that the wall-breaking processing method involved in the present invention can significantly make the protein molecules migrate to the low-molecular-weight region, dissociate the high-level protein structure, and decompose some macromolecules. Easily digested and absorbed by the human body.

(4) Evaluation of sterilization effect

Take the products prepared in Example 1 and Example 3-5, and test the total number of microorganisms. Chlorella powder is the control. The results are shown in Table 3. It can be seen that all treatment groups meet the national limit requirements, and when the humidity is 45-65%, the total number of colonies is significantly reduced.

table 3

The applicant declares that the present invention illustrates a microalgae wall-breaking processing method of the present invention and its application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be able to implement. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the specific technical features described in the above-mentioned specific embodiments can be combined in any suitable manner unless they are inconsistent. In order to avoid unnecessary repetition, the present invention provides The combination method will not be specified otherwise.

Claims (9)

1. a microalgae wall-breaking processing method, is characterized in that, described microalgae wall-breaking processing method comprises: the microalgae that humidity is 25-75% is carried out screw extrusion processing, and the material after the extrusion is dried again, Pulverize to obtain broken-wall microalgae powder. 2. The microalgae wall-breaking processing method according to claim 1, wherein the humidity of the microalgae is 55-65%. 3 . The microalgae wall-breaking processing method according to claim 1 or 2 , wherein the initial temperature T ₀ of the screw extrusion treatment is 80-130° C. 4 . 4. The microalgae wall-breaking processing method according to any one of claims 1-3, wherein the initial temperature T ₀ of the screw extrusion treatment is 85-125°C. 5 . The microalgae wall-breaking processing method according to claim 1 , wherein the end temperature T ₁ of the screw extrusion treatment is 130-220° C. 6 . 6 . The microalgae wall-breaking processing method according to claim 1 , wherein the end temperature T ₁ of the screw extrusion treatment is 140-195° C. 7 . 7. The microalgae wall-breaking processing method according to any one of claims 1-6, wherein the total duration _t1 of the screw extrusion and heat treatment is 10-200s. 8. The microalgae wall-breaking processing method according to any one of claims 1-7, wherein the total duration _t1 of the screw extrusion and heat treatment is 20-150s. 9. The application of the microalgae wall-breaking processing method according to any one of claims 1-8 in the preparation of microalgae food.

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