A microalgae plant milk beverage and preparation method thereof

Abstract

The invention relates to the technical field of food processing, and in particular to a method for preparing a microalgae plant milk beverage, comprising: S1, selecting fresh microalgae in which protein accounts for ≥40% of cell dry weight, oil accounts for ≤15% of cell dry weight, and starch accounts for ≤30% of cell dry weight; S2, preparing algae pulp with drinking water, breaking algae cells with a high-pressure homogenizer to obtain broken algae pulp; S3, adding water to dilute the broken algae pulp, adding 350-5000 units / kg of cellulase, 500-50000 units / kg of protease, 500-3000 units / kg of amylase and 1000-3000 units / kg of saccharifying enzyme to carry out enzymolysis based on the weight of the diluted algae pulp, and after the reaction is completed, adding an additive of less than 5g / 100mL, stirring and mixing evenly; S4, heating to 50-80°C, and homogenizing again; S5, sterilizing and filling to obtain a finished product. The present invention adopts microalgae with high protein content to prepare a plant milk beverage, and the protein / oil or protein / starch ratio of the plant milk beverage is reasonable, thereby making up for the problem of low protein / calorie ratio of the plant milk beverage.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to a microalgae plant milk beverage and a preparation method thereof. Background Art

[0002] Milk is a daily drink for humans, playing an important role in children's growth and development, adult health maintenance, and nutritional support for the elderly. However, milk may cause lactose intolerance or allergic reactions in some people, which has prompted people to look for alternatives to milk. Plant milk drinks are usually made from plant ingredients such as soybeans, almonds, oats, rice, etc. They contain a small amount of saturated fat and no cholesterol, providing a nutritious choice for people who are lactose intolerant, allergic to milk, vegetarians, or seeking to reduce the consumption of animal products. It can be used as a substitute for milk. In addition, the production of plant milk drinks has a much smaller impact on the environment than traditional animal husbandry. With technological advances and growing consumer demand, the quality and taste of plant milk drinks have also been significantly improved, becoming an important part of sustainable dietary choices.

[0003] At present, the main plant milk beverage products on the market include soy milk, peanut milk, nut milk such as almond or almond kernel, cereal milk such as oat or rice, and coconut milk. Soy milk has a high protein content (4.0g / 100mL for Doubendou), but it often contains anti-nutritional factors such as chymosin inhibitors, and many people do not accept the beany smell of soy milk; peanut milk has a low protein content, and the current peanut milk products are basically compounded with milk, which still contain milk ingredients. In addition, some people are allergic to peanut protein. Nuts such as almonds and almond kernels have a high fat content, and their dairy products also have a high fat content, but a low protein content (almond milk 0.6g / 100mL, almond milk 1.2g / 100mL), and the nutrition is relatively simple. The protein content of cereal milk such as oat and rice is relatively low (the protein content of products without milk is below 1.0g / 100mL), and the main component is starch, so the carbohydrate content is high, the protein / calorie value is low, and the nutrition is relatively simple. Coconut milk has a lower protein content (less than 1%) and a higher saturated fat content. In short, although people expect to replace animal milk with plant milk drinks, the plant protein milk products currently on the market have their own nutritional deficiencies, and no product can fully match animal milk in terms of nutrition.

[0004] For pure plant milk drinks without animal milk, for example, peanuts and tree nuts have a high fat content. If the protein content in dairy products is to be increased, the fat content of the products will also increase, which is not conducive to the stability of the drinks and can easily cause the calorie content of the drinks to be too high. For example, oats and rice have a high starch content. If the protein content in oat milk and rice milk products is to be increased, the starch content in the products will also increase, and the carbohydrate content and calories will increase. The fat and starch content in the drinks will not only affect the stability and taste of the drinks, but also discourage some people who are controlling their calorie intake and weight.

[0005] In view of the problems existing in existing plant milk beverages, the present invention proposes a solution. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a microalgae plant milk beverage and a preparation method thereof, wherein the plant milk beverage is made from protein-rich microalgae as raw materials. There are many types of microalgae and the nutritional composition structure of the microalgae can be changed by slightly changing the culture conditions. Compared with dairy products made from peanuts, nuts, oats, rice, etc., the present invention can more easily obtain a better protein / oil ratio or protein / starch ratio; by selecting good algae species and appropriate culture conditions, the microalgae contain higher contents of multiple important nutrients, such as lutein, β-carotene, dietary fiber, etc., thereby preparing a high-quality, nutritious, protein-containing plant milk beverage product, which solves the technical problems of the existing plant milk beverages such as the high relative protein content of oil / starch and the single nutrition.

[0008] (II) Technical solution

[0009] In a first aspect, the present invention provides a method for preparing a microalgae plant milk beverage, comprising:

[0010] S1. Selection of microalgae raw materials: The microalgae raw materials should be fresh microalgae with protein accounting for ≥40% of the cell dry weight, oil accounting for ≤15% of the cell dry weight, and starch accounting for ≤30% of the cell dry weight;

[0011] S2. Cell disruption: Algae slurry is prepared with drinking water, and algae cells are broken by a high-pressure homogenizer to obtain broken algae slurry;

[0012] S3, enzymolysis: add water to dilute the broken algae pulp, add 350-5000 units / kg of cellulase, 500-50000 units / kg of protease, 500-3000 units / kg of amylase and 1000-3000 units / kg of saccharifying enzyme to carry out enzymolysis based on the weight of the diluted algae pulp, and after the reaction is completed, add <5g / 100mL of additives and stir to mix evenly;

[0013] S4, homogenization: heating the mixture obtained in S3 to 50-80° C. and transferring it to a high-pressure homogenizer for homogenization at least once;

[0014] S5, sterilization and filling: sterilize the mixture after homogenization in S4 and then fill it or sterilize it after filling to obtain the finished product.

[0015] According to a preferred embodiment of the present invention, in S1, the microalgae is any one or more of Chlamydomonas reinhardtii, Chlorella vulgaris, Scenedesmus, Euglena, Spirulina, Dunaliella salina, Pseudochlorophyll and any one of the high-yield protein mutant strains of any of the foregoing.

[0016] According to a preferred embodiment of the present invention, in S2, the pressure of the high-pressure homogenizer is 100-120 MPa; after homogenization, particles below 1 μm in the cell plasma account for more than 90% of the total number of particles, and particles below 300 nm account for more than 50% of the total number of particles.

[0017] According to a preferred embodiment of the present invention, in S2, before using a high-pressure homogenizer to break the algae powder / algae mud, water is added to make the algae cell dry matter concentration 50-200 g / L. The higher the algae cell dry matter concentration, the greater the homogenization pressure used. For example, when the algae cell dry matter concentration is below 100 g / L, a homogenization pressure of 100 MPa can be used. When the algae cell dry matter concentration exceeds 100 g / L, a homogenization pressure greater than 100 MPa can be used.

[0018] According to a preferred embodiment of the present invention, in S3, during the enzymatic hydrolysis process, water is added to dilute the broken algae slurry until the dry matter content of the microalgae is 10g / L-100g / L and the protein content is ≥1.0g / 100mL; the enzymatic hydrolysis conditions are: react at 50±5°C for 45-90min.

[0019] According to a preferred embodiment of the present invention, in S3, the cellulase is a food-grade cellulase. The protease is one or a combination of food-grade alkaline protease, neutral protease, papain, bromelain, trypsin and pepsin, the amylase is one or a combination of α-amylase and pullulanase, and the saccharifying enzyme is one or a combination of glucoamylase or β-amylase.

[0020] According to a preferred embodiment of the present invention, in S3, the additive is one or more of an emulsifier, a thickener, a flavoring agent, and a pH adjuster; the amount of the emulsifier added is 0-3.0 g / 100 mL, and the amount of the thickener added is 0-1.0 g / 100 mL.

[0021] The emulsifier is one or more of polysorbate, monoglyceride and diglyceride, fatty acid sucrose ester, sorbitan fatty acid ester, sodium / calcium stearoyl lactylate, and polyoxyethylene ether; the thickener is one or a combination of xanthan gum, maltodextrin, alginate, carrageenan, guar gum, sodium carboxymethyl cellulose, and pectin; the flavoring agent is one or more of chocolate, strawberry flavor, vanilla flavor, mint flavor, concentrated fruit juice, acidity regulator (such as citric acid, lactic acid, etc.), and vegetable oil; the pH adjuster is sodium carbonate, phosphate or citrate.

[0022] Most of the microalgae-derived proteins are alkaline-soluble gluten proteins, which are poorly soluble in common neutral or weakly acidic beverage systems and are prone to protein instability; therefore, it is preferred to add an appropriate amount of sodium carbonate, phosphate or citrate to help adjust the pH value of microalgae milk drinks to a neutral or alkaline environment, improve the taste and extend the shelf life. Phosphates can also maintain the softness and lubricity of egg drinks and reduce the degree of protein denaturation during high-temperature sterilization.

[0023] According to a preferred embodiment of the present invention, in S4, the pressure of the homogenization treatment is 60-80 MPa, and the homogenization is repeated 1-3 times.

[0024] According to a preferred embodiment of the present invention, in S5, the sterilization conditions are: one or a combination of treatment at 135-150°C for 2-10s, pasteurization at 75-100°C and treatment at 100-121°C for 10-20 minutes; sterilization is performed before or after filling.

[0025] In a second aspect, the present invention provides a microalgae plant milk beverage, which is prepared by the preparation method of any one of the above embodiments.

[0026] (III) Beneficial effects

[0027] The main technical effects of the present invention are:

[0028] (1) The present invention uses microalgae with high protein content as the raw material for the production of plant milk beverages. By utilizing the diversity of microalgae species, short microalgae culture cycle, rapid culture, rich microalgae nutrition and easy adjustment of nutrient composition structure, microalgae that meet specific nutritional composition requirements can be used as raw materials to produce plant milk beverage products with better protein / oil or protein / starch content ratios, making up for the low protein / oil or protein / starch ratios in existing plant milk beverages such as peanut milk, nut milk, oat milk, and rice milk, and further providing a new type of plant milk beverage with high protein content and very low oil content or starch content. As a high-protein, low-fat, and low-calorie food raw material, there is currently no high-level biomass raw material comparable to microalgae.

[0029] Normally, the proportion of protein, oil and starch in nuts such as peanuts, almonds or almond kernels, and grains such as oats or rice is basically fixed, with only small fluctuations in different origins and subspecies, so it is difficult to adjust the proportion of protein, oil and starch in the dairy products prepared from them. However, as a single-cell plant, microalgae has a short growth cycle and rapid cultivation. The composition ratio of protein, oil and starch in microalgae cells can be adjusted by adjusting the culture medium components (such as nitrogen source concentration and nitrogen source form, C / N ratio) or culture conditions (such as autotrophic light intensity, light-dark cycle, flow acceleration of heterotrophic culture medium, pH, dissolved oxygen) to stress conditions; microalgae single-cell organisms can also be induced to obtain mutants with certain metabolic preferences. These advantages can be used to produce protein drinks made from microalgae while maintaining a high protein content, while reducing the content of sugars such as oil or starch to meet the needs of the relevant population.

[0030] (2) Currently, conventional microalgae are added to food or beverages with their extracts, such as algae-derived DHA, algae-derived protein, etc., all of which use microalgae as raw materials. Through complex extraction and purification processes, the target components present in the microalgae cells are extracted and added to food or beverages. However, this method not only has high process costs, but also leads to waste of microalgae biomass and residual extractants, and whole algae are rarely made into food or beverages. The present invention uses whole microalgae cells to make plant protein milk, which not only can obtain high-protein nutrition, but also the algae cells are rich in carotenoids (including but not limited to: lutein for protecting eyesight, antioxidant astaxanthin, fucoxanthin for promoting lipid metabolism and protecting the liver, etc.), lipids, vitamins, polysaccharides, dietary fiber and trace elements. By adding whole algae to beverages, these ingredients can be fully utilized, making microalgae beverages a more comprehensive nutritional supplement.

[0031] (3) Most microalgae cells have tough cell walls. Before enzymatic hydrolysis, the cells must be broken to dissolve the cell contents so that the nutrients can enter the beverage and be absorbed. Traditional wall-breaking machines used by households or production enterprises to process soybeans, peanuts, etc. mainly achieve the wall-breaking effect by means of high-speed shearing of the cutter and violent collision and friction between particles. However, microalgae are single cells and the particles are very small, so they cannot be broken by traditional wall-breaking machines. For this reason, the present invention uses a high-pressure homogenizer for cell-breaking treatment. In addition, the main component of the algae cell wall is cellulose. The cell wall debris is easy to flocculate and precipitate, and adsorb protein macromolecules during the precipitation process, which is not conducive to the stability of the beverage phase. For this reason, the present invention adjusts the conditions and number of treatments of high-pressure homogenization to achieve a refinement degree of "more than 90% of particles below 1 μm and more than 50% of particles below 300 nm", and cooperates with the "cellulase" added in the enzymatic hydrolysis process to perform enzymatic hydrolysis and further homogenization treatment, so that the cellulose cell wall is further refined and hydrolyzed into oligosaccharides or oligosaccharides to maintain the physical stability of the beverage. After enzymatic hydrolysis, high-pressure homogenization treatment is performed again to further improve the uniformity and stability of the milk drink.

[0032] (4) Most algae-derived proteins are alkali-soluble gluten proteins. The present invention adds a pH adjuster such as sodium carbonate, phosphate or citrate to maintain the pH of the milk beverage in a neutral to alkaline environment, and assists in partial hydrolysis with protease to promote the dissolution of algae-derived proteins to enhance the stability of the beverage. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a flow chart of a method for preparing a microalgae plant milk beverage. DETAILED DESCRIPTION

[0034] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0035] like Figure 1 FIG. 1 is a flow chart of a method for preparing a microalgae plant milk beverage of the present invention, which comprises the following steps:

[0036] (1) Selection of microalgae raw materials: The microalgae raw materials are algae powder or algae mud with protein accounting for ≥40% of the cell dry weight, oil accounting for ≤15% of the cell dry weight, and starch accounting for ≤30% of the cell dry weight.

[0037] The microalgae is any one or more of Chlamydomonas reinhardtii, Chlorella vulgaris, Scenedesmus, Euglena, Spirulina, Dunaliella salina, Microchloropsis pseudochloropsis and any one of the high-yield protein mutant strains of the foregoing.

[0038] (2) Cell disruption: Use a high-pressure homogenizer to break the algae powder or algae mud to obtain cell slurry. The pressure of the high-pressure homogenizer is 100-120 MPa, and the number of homogenizations is 1-3 times; after homogenization, particles below 1 μm in the cell slurry account for more than 90% of the total number of particles, and particles below 300 nm account for more than 50% of the total number of particles.

[0039] Before using a high-pressure homogenizer to break the algae powder / algae mud, water is added to make the algae cell dry matter concentration 50-200g / L. When the raw material is dry algae powder, the amount of water added is relatively large. When the raw material is algae mud collected by a centrifuge, the amount of water added can be reduced because the algae mud itself contains water.

[0040] (3) Enzymatic hydrolysis: Add water to dilute the broken algae pulp, and add 350-5000 units / kg of cellulase, 500-50000 units / kg of protease, 500-3000 units / kg of amylase and 1000-3000 units / kg of saccharifying enzyme based on the weight of the diluted algae pulp for enzymatic hydrolysis. After the reaction is completed, add an additive of less than 5g / 100mL and stir to mix evenly.

[0041] The cellulase is food grade cellulase, the protease is one or a combination of food grade alkaline protease, neutral protease, papain, bromelain, trypsin and pepsin, the amylase is one or a combination of α-amylase and pullulanase, and the saccharifying enzyme is one or a combination of glucoamylase or β-amylase.

[0042] When adding water to the broken algae slurry, dilute the broken algae slurry with water until the dry matter content of the microalgae is 10g / L-100g / L, and the protein content is preferably ≥1.0g / 100mL. The enzymatic hydrolysis conditions are: react at 50±5°C for 45-90min.

[0043] After the enzymatic reaction, the starch is hydrolyzed to generate dextrin, oligosaccharides, oligosaccharides and a small amount of glucose or maltose to improve the taste of food and increase sweetness. The sweetness of the drink can be adjusted by adjusting the amount of saccharifying enzyme. In the microalgae plant milk drink of the present invention, not only does it not need to add sugars such as sucrose, but it also does not need to add natural or artificial sweeteners (such as aspartame, acesulfame potassium, sucralose, etc.). The sweetness can be adjusted by controlling the amount and time of saccharifying enzyme addition.

[0044] After the enzymatic hydrolysis reaction is completed, a small amount of additives is added to promote the stability of the beverage and adjust the flavor. The additives are one or more of an emulsifier, a thickener, a flavoring agent, and a pH adjuster; the amount of the emulsifier added is 0-3.0g / 100mL, and the amount of the thickener added is 0-1.0g / 100mL.

[0045] After high-pressure homogenization and cellulase treatment, the cellulose cell wall has become very fine, so there is no need to add a large amount of thickener or emulsifier to maintain the stability of the beverage. Adding 0-3.0g / 100mL of emulsifier and 0-1.0g / 100mL of thickener can prevent the beverage from sedimentation and stratification.

[0046] The emulsifier is one or more of polysorbate, monoglyceride and diglyceride, sucrose fatty acid ester, sorbitan fatty acid ester, sodium / calcium stearoyl lactylate, and polyoxyethylene ether; the thickener is one or a combination of xanthan gum, maltodextrin, alginate, carrageenan, guar gum, sodium carboxymethyl cellulose, and pectin; the flavoring agent is one or more of chocolate, strawberry flavor, vanilla flavor, mint flavor, concentrated fruit juice, acidity regulator (such as citric acid, lactic acid, etc.), and vegetable oil; the pH adjuster is phosphate, sodium carbonate or citrate.

[0047] Most of the microalgae-derived proteins are alkaline-soluble gluten proteins, which have poor solubility in common neutral or weakly acidic beverage systems and are prone to protein instability. Therefore, it is preferred to add an appropriate amount of phosphate, sodium carbonate or citrate to help adjust the pH value of the microalgae milk beverage to a neutral or alkaline environment (such as pH = 7.0-8.0), thereby improving the taste and extending the shelf life.

[0048] (4) Homogenization: The mixture obtained in step (3) is heated to 50-80° C. and transferred to a high-pressure homogenizer for homogenization at least once. The pressure of the homogenization is 60-80 MPa, and the homogenization is repeated 1-3 times. After the high-pressure homogenization, the enzymatic reaction products and additives are evenly mixed, the cell wall cellulose particles are further refined, and the beverage phase is more uniform and stable.

[0049] (5) Sterilization and filling: The mixture after homogenization in step (4) is sterilized and then immediately filled to obtain the finished product.

[0050] The ultra-high temperature instantaneous sterilization condition is 135-150℃ for 2-10s; filling can be done in 1000mL or 250mL Tetra Pak-style packaging boxes. In addition, pasteurization can be carried out after filling, or high temperature sterilization can be carried out at 100-121℃ for 10-20min.

[0051] In addition, in addition to the above steps, microalgae culture and algae cell collection steps may also be included. Microalgae culture is mainly carried out by heterotrophic culture. For example, SE medium or BG-11 medium can be used as the basic formula for the culture of Chlorella, the C / N ratio in the fermentation medium and the feed medium can be controlled, and ammonium nitrogen that is more easily absorbed and utilized is used as the only nitrogen source. Heterotrophic-light-induced serial culture, high dissolved oxygen induction, suitable pH induction, hydrogen peroxide induction, plant growth regulator induction and other methods are used to increase the protein and carotenoid content in the algae cells as much as possible, and reduce the oil / starch content, thereby providing algae raw materials with better nutritional component structure for microalgae milk drinks.

[0052] The present invention is described below with reference to specific embodiments.

[0053] Example 1

[0054] This embodiment uses Chlorella pyrenoidosa as a raw material for processing plant milk to prepare a microalgae milk beverage. The steps are as follows:

[0055] (1) Through heterotrophic fermentation, 75 L of fermentation liquid with an algae dry matter concentration of 100 g / L and a cell protein content of 56% (w / w, dry matter) is obtained, and algae cells are separated by a disc centrifuge to obtain about 20 L of algae slurry with an algae cell dry matter concentration of about 350 g / L. The dry matter of the protein core chlorella has an oil content of 10 g / 100 g, a starch content of 30 g / 100 g, a β-carotene content of 2.2 mg / 100 g, and a lutein content of 116 mg / 100 g.

[0056] (2) Place the algae pulp in a 100L storage tank, add drinking purified water to make the total volume of the algae pulp 70L and the algae cell dry matter concentration 100g / L, and homogenize it three times with a high-pressure homogenizer at 110MPa to obtain a broken algae pulp. In the broken algae pulp, particles below 1μm account for 90%, and particles below 300nm account for 53%.

[0057] (3) Place the broken algae pulp in a 200L mixing tank and add water to 131L. At this time, the dry matter content of the microalgae is 53.4g / L (5.34g / 100mL). Stir and mix while heating until all the substances are evenly dispersed or dissolved. When the temperature reaches 50°C, add 1000 units / kg of food-grade cellulase, 5000 units / kg of protease, 500 units / kg of medium-temperature α-amylase, 500 units / kg of pullulanase and 1500 units / kg of glucoamylase based on the total weight of the cell pulp, and stir for 1h to carry out a moderate hydrolysis reaction. After the reaction, add 0.2g / 100ml of dipotassium hydrogen phosphate, adjust the pH to 7.0-7.5 with sodium citrate, add 0.5g / 100mL of rapeseed oil, 0.05g / 100mL of monostearate glyceryl, 0.05g / 100mL of sucrose fatty acid ester, and 0.08g / 100mL of carrageenan to promote protein dissolution and beverage stability.

[0058] (4) The temperature was adjusted to 70°C and the mixture was transferred to the homogenizer again and homogenized twice at 80 MPa.

[0059] (5) After homogenization, the product is transported to an ultra-high temperature instantaneous sterilizer and sterilized at 143°C for 5 seconds. It is then immediately filled in an aseptic filling system and packaged in 250 mL Tetra Pak packages.

[0060] The drink contains 3g / 100mL of protein, 0.12mg / 100mL of beta-carotene, 6.19mg / 100mL of lutein, 1.60g / 100mL of carbohydrates, and 0.53g / 100mL of fat.

[0061] Example 2

[0062] This example uses wild-type green Chlorella as a raw material for processing plant milk to prepare a microalgae milk beverage. The steps are as follows:

[0063] (1) Through heterotrophic fermentation, 75 L of fermentation liquid with an algae dry matter concentration of 120 g / L and a cell protein content of 50% (w / w, dry matter) was obtained, and algae cells were separated by a disc centrifuge to obtain about 20 L of algae slurry with an algae cell dry matter concentration of about 400 g / L. The wild-type green Chlorella has a fat content of 15 g / 100 g, a starch content of 25 g / 100 g, and a β-carotene content of 5.2 mg / 100 g in dry matter.

[0064] (2) Place the algae pulp in a 200L storage tank, add drinking purified water to make the total volume of the algae pulp 160L and the algae cell dry matter concentration 50g / L, and homogenize it three times with a high-pressure homogenizer at 100MPa to obtain a broken algae pulp. In the broken algae pulp, particles below 1μm account for 95%, and particles below 300nm account for 60%.

[0065] (3) Place the broken algae pulp in a 250L mixing tank, add water to 200L, at which point the dry matter content of the microalgae is 40.0g / L (4g / 100mL), stir and mix while heating until all substances are evenly dispersed or dissolved, add 1000 units / kg of food-grade cellulase, 6000 units / kg of protease, 600 units / kg of medium-temperature α-amylase and 2500 units / kg of β-amylase based on the total weight of the cell slurry when the temperature reaches 55°C, and stir for 90 minutes for hydrolysis. Add 0.2g / 100ml of disodium hydrogen phosphate, 0.05g / 100ml of dehydrated sorbitan fatty acid ester, and 1g / 100mL of chocolate, and adjust the pH to 7.0-8.0 with sodium citrate to promote protein dissolution and beverage stability.

[0066] (4) The temperature was adjusted to 70°C and the mixture was transferred to the homogenizer again and homogenized twice at 80 MPa.

[0067] (5) After homogenization, the product is transported to an ultra-high temperature instantaneous sterilizer and sterilized at 150°C for 3 seconds. It is then immediately filled in an aseptic filling system and packaged in 250 mL Tetra Pak packages.

[0068] The protein content of the drink is 2.0g / 100mL, β-carotene is 0.208mg / 100mL, carbohydrates are 1g / 100mL, and fat is 0.6g / 100mL.

[0069] Example 3

[0070] This embodiment uses Scenedesmus as a raw material for processing plant milk to prepare a microalgae milk beverage. The steps are as follows:

[0071] (1) Through heterotrophic fermentation, 75 L of fermentation liquid with an algae dry matter concentration of 80 g / L and a cell protein content of 40% (w / w, dry matter) was obtained, and the algae cells were separated by a disc centrifuge to obtain about 20 L of algae slurry with an algae cell dry matter concentration of about 300 g / L. The oil content of the Scenedesmus was 5 g / 100 g, the starch content of the Scenedesmus was 10 g / 100 g, and the lutein content was 1200 mg / 100 g.

[0072] (2) Place the algae pulp in a 100L storage tank, add drinking water to make the total volume of the algae pulp 80L and the algae cell dry matter concentration 75g / L, and homogenize it three times with a high-pressure homogenizer at 100MPa to obtain broken algae pulp. In the broken algae pulp, particles below 1μm account for 90%, and particles below 300nm account for 51%.

[0073] (3) Place the crushed algae pulp in a 100L mixing tank, at which the dry matter content of the microalgae is 75g / L (7.5g / 100mL), stir and mix while heating until all substances are evenly dispersed or dissolved. When the temperature reaches 50°C, add 1000 units / kg of food-grade cellulase, 8000 units / kg of protease, 600 units / kg of α-amylase, and 1000 units / kg of β-amylase based on the total weight of the cell pulp, and stir for 1 hour for hydrolysis. After the hydrolysis is completed, add 0.4g / 100ml of dipotassium hydrogen phosphate, 0.05g / 100ml of dehydrated sorbitan fatty acid ester, use 1.0g / 100ml of lemon essence, and use sodium citrate to adjust the pH to 7.0-8.0 to promote protein dissolution and beverage stability.

[0074] (4) The temperature was adjusted to 70°C and the mixture was again transferred to the homogenizer and homogenized three times at 80 MPa.

[0075] (5) After homogenization, the product is transported to an ultra-high temperature instantaneous sterilizer and sterilized at 135°C for 8 seconds. It is then immediately filled in an aseptic filling system and packaged in 250 mL Tetra Pak packages.

[0076] The drink contains 3.0g / 100mL of protein, 90mg / 100mL of lutein, 0.75g / 100mL of carbohydrates, and 0.375g / 100mL of fat.

[0077] Example 4

[0078] This embodiment uses Chlamydomonas reinhardtii as a raw material for processing plant milk to prepare a microalgae milk beverage. The steps are as follows:

[0079] (1) Cultivating Chlamydomonas reinhardtii by photoautotrophy and harvesting algae mud, the dry matter of the algae has a protein content of 55%, a fat content of 5%, a starch content of 20%, a β-carotene content of 10mg / 100g, and a high content of eight essential amino acids for the human body. Chlamydomonas reinhardtii is rich in linolenic acid, arachidonic acid, linoleic acid, Ω-3, 6, 9 unsaturated fatty acids, 20% dietary fiber and vitamins B2, B6, B12, D2, D3, VC, VE, niacin, pantothenic acid, chlorophyll, biotin and nucleotides, β-carotene, lutein, zeaxanthin, β-cryptoxanthin, and minerals such as phosphorus, potassium, sodium, calcium, magnesium, iron, copper, manganese, zinc, and selenium.

[0080] (2) Take 10kg of wet algae mud (the water content of the algae mud is 75%) and place it in a 100L storage tank. Add drinking purified water to make the total volume of the algae slurry 50L and the algae cell dry matter concentration 50g / L. Use a high-pressure homogenizer to homogenize twice at 100MPa to obtain broken algae slurry. In the broken algae slurry, particles below 1μm account for 92%, and particles below 300nm account for 56%. The cell wall of Chlamydomonas reinhardtii is thin and not tough. Its cell wall is a multi-layered polysaccharide protein, and only one high-pressure homogenization is needed to break the cells. Enzymatic hydrolysis can be done without adding cellulase or with only a small amount of cellulase.

[0081] (3) Place the broken algae pulp in a 100L mixing tank, add water to 80L, at which time the dry matter content of the microalgae is 31.25g / L (3.125g / 100mL), stir and mix while heating until all substances are evenly dispersed or dissolved, add 400 units / kg of cellulase, 1000 units / kg of protease, 1000 units / kg of α-amylase, and 1500 units / kg of glucoamylase based on the total weight of the cell slurry when the temperature reaches 50°C, and stir for 70 minutes for hydrolysis. After the hydrolysis is completed, add 0.04g / 100ml of disodium hydrogen phosphate, 0.05g / 100ml of sucrose fatty acid ester, and 0.08g / 100mL of xanthan gum, and adjust the pH to 7.0-8.0 using sodium citrate.

[0082] (4) The temperature was adjusted to 65°C and the mixture was transferred to the homogenizer again and homogenized once at 80 MPa.

[0083] (5) After homogenization, the product is transported to an ultra-high temperature instantaneous sterilizer and sterilized at 135°C for 5 seconds. It is then immediately filled in an aseptic filling system and packaged in 250 mL Tetra Pak packages.

[0084] The protein content of the drink is 1.718g / 100mL, beta-carotene is 0.3125mg / 100mL, carbohydrates are 0.625g / 100mL, and fat is 0.156g / 100mL.

[0085] Example 5

[0086] In this example, the amount of glucoamylase added is set to 500 units / Kg based on Example 1.

[0087] Example 6

[0088] In this example, the amount of glucoamylase added is set to 3000 units / Kg based on Example 1.

[0089] Example 7

[0090] This example uses the protein-nucleated Chlorella germplasm resources of Example 1, but changes the culture conditions of heterotrophic fermentation. The fermentation culture conditions in Example 1 are: BG-11 is used as the fermentation medium, supplemented with 60g / L of glucose. 50L of the prepared culture medium was dissolved in a 100L fermenter, sterilized at 121°C for 30min, cooled to 25-30°C, and inoculated with the protein-nucleated Chlorella cultured in a 5L fermenter. After 5 days of fermentation, feed culture was started, and the feed rate was adjusted according to the sugar consumption. The feed culture medium formula was 60g / L glucose and 1g / L ammonium sulfate. After 7 days of fermentation, 75L of fermentation liquid with an algae dry matter concentration of 100g / L and a cell protein content of 56% (w / w, dry matter) was obtained.

[0091] The conditions of heterotrophic fermentation culture in this embodiment are changed as follows: BG-11 is used as the fermentation medium, and 40g / L of glucose is supplemented. 50L of the prepared medium is dissolved in a 100L fermenter, sterilized at 121℃ for 30min, cooled to 25-30℃, and inoculated with protein nucleus chlorella cultured in a 5L fermenter. After 5 days of fermentation, fed-batch culture is started, and the feeding rate is adjusted according to the sugar consumption. The formula of the feed medium is 60g / L glucose and 1.5g / L ammonium sulfate. During the culture process, ammonia water is used to adjust the pH between 6.2-6.8. After 7 days of fermentation, 75L of fermentation liquid with an algae dry matter concentration of 105g / L and a cell protein content of 65% (w / w, dry matter) is obtained. The protein nucleus chlorella has an oil content of 15%, a starch content of 10%, a β-carotene content of 4.8mg / 100g, and a lutein content of 100mg / 100g. The algae cells were separated by a disc centrifuge to obtain about 20 L of algae slurry with an algae cell dry matter concentration of about 390 g / L.

[0092] (2) Place the algae slurry in a 100L storage tank, add drinking water to make the total volume of the algae slurry 75L, and the algae cell dry matter concentration 104g / L, and homogenize it three times with a high-pressure homogenizer at 120MPa to obtain cell wall slurry. In the cell wall slurry, particles below 1μm account for 95%, and particles below 300nm account for 60%.

[0093] (3) Place the broken cell slurry in a 200L mixing tank, add water to 150L, ​​at which point the dry matter content of the microalgae is 52g / L (5.2g / 100mL), stir and mix while heating until all substances are evenly dispersed or dissolved, add 1000 units / kg of food-grade cellulase, 5500 units / kg of protease, 1500 units / kg of medium-temperature α-amylase and 2000 units / kg of glucoamylase based on the total weight of the cell slurry when the temperature reaches 50°C, stir for 1.5h for moderate hydrolysis. Add 0.2g / 100ml of dipotassium hydrogen phosphate, adjust the pH to 7.0-8.0 with sodium citrate, add 0.5mL / 100mL of coconut oil, 0.07g / 100mL of monostearate glycerol, 0.05g / 100mL of sucrose fatty acid ester, and 0.07g / 100mL of xanthan gum, and mix evenly.

[0094] (4) The temperature was adjusted to 70°C and the mixture was transferred to the homogenizer again and homogenized twice at 80 MPa.

[0095] (5) After homogenization, the product is transported to an ultra-high temperature instantaneous sterilizer and sterilized at 145°C for 5 seconds. It is then immediately filled in an aseptic filling system and packaged in 1000 mL Tetra Pak packages.

[0096] The drink contains 3.38g / 100mL of protein, 0.25mg / 100mL of beta-carotene, 5.2mg / 100mL of lutein, 0.52g / 100mL of carbohydrates, and 0.78g / 100mL of fat.

[0097] Comparative Example 1

[0098] This comparative example is based on Example 1 except that step (4) is omitted.

[0099] Comparative Example 2

[0100] This comparative example is based on Example 1 except that the pH regulator is omitted.

[0101] Comparative Example 3

[0102] In this comparative example, a household wall-breaking machine was used to break the wall for 30 min instead of homogenizing three times at 100 MPa with a high-pressure homogenizer.

[0103] The protein content, fat content, starch content, and energy value of the microalgae milk beverages in the above embodiments were calculated or tested, and the results are shown in Table 1:

[0104] Table 1:

[0105]

[0106]

[0107] Note: *This indicator is the total energy intake caused by consuming 1g of protein while consuming fat and carbohydrates.

[0108] Sensory tests were performed on the microalgae milk beverages of Examples 1-7 and Comparative Example 3. Ten sensory assessors performed descriptive tests on the same batch of samples of the examples, and the results are shown in Table 2.

[0109] Table 2: Sensory evaluation results of Examples 1-7 and Comparative Example 3

[0110]

[0111] Scoring rules: sweetness score 0-9 points, representing from not sweet to very sweet, the higher the score, the higher the sweetness; smoothness score 0-9 points, representing the sensory perception from not smooth to smooth, 6.5±0.2 points represents the best smoothness; consistency score 0-9 points, representing the sensory perception from thin to thick. The cell disruption method used in Comparative Example 3 is not suitable for microalgae, the cell disruption effect is poor, the cellulose cell wall is not destroyed, the enzymatic hydrolysis effect and saccharification effect are poor, the sweetness is extremely low, the taste is poor, and the smoothness and consistency are poor.

[0112] From the comparison between Example 1 and Example 7, it can be seen that even with the same microalgae germplasm resources, only the fermentation culture conditions need to be adjusted, such as increasing the content of ammonium nitrogen in the feed medium, and using the method of adding ammonia water to keep the pH of the fermentation system neutral and slightly acidic, which can promote the algae cells to accumulate more protein, increase the protein content from 56% to 65%, and relatively reduce the accumulation of oil and starch in the algae cells, and reduce the oil and starch content in the algae cells. It can be seen that compared with the method of producing protein drinks using higher plants as raw materials, the present invention can obtain microalgae biomass with high protein, low starch and low oil composition through customized culture conditions, and use the microalgae biomass to prepare low-fat, low-carb and low-calorie protein drinks.

[0113] The microalgae milk products prepared in Examples 1-7 and Comparative Examples 1-3 were placed at room temperature for 21 days, poured into a glass and left to stand for 3 hours, and the stratification was observed. The results are shown in the following table:

[0114] Table 3:

[0115] Stability (whether it is layered) Example 1 Stable, no stratification Example 2 Stable, no stratification Example 3 Stable, no stratification Example 4 Stable, no stratification Example 5 Stable, no stratification Example 6 Stable, no stratification Example 7 Stable, no stratification Comparative Example 1 Unstable, stratified Comparative Example 2 Slightly delaminated Comparative Example 3 Unstable, obvious delamination

[0116] In summary, the present invention provides a low-fat, low-sugar, and low-calorie plant protein dairy product using microalgae as raw materials. The plant protein dairy product contains high protein and can be used as a substitute for milk, providing an ideal protein drink for people who are allergic to milk or lactose intolerant, who pursue low calorie intake, and who control their body fat percentage.

[0117] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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 a microalgae plant milk beverage, characterized in that: It includes: S1. Selection of microalgae raw materials: fresh microalgae with protein accounting for ≥40% of cell dry weight, oil accounting for ≤15% of cell dry weight, and starch accounting for ≤30% of cell dry weight should be selected as microalgae raw materials; S2. Cell disruption: Algae slurry is prepared with drinking water, and algae cells are broken by a high-pressure homogenizer to obtain broken algae slurry; The pressure of the high-pressure homogenizer is 100-120MPa; after homogenization, particles below 1μm in the cell plasma account for more than 90% of the total number of particles, and particles below 300nm account for more than 50% of the total number of particles; S3, enzymolysis: adding water to dilute the broken algae pulp, adding 350-5000 units / kg of cellulase, 500-50000 units / kg of protease, 500-3000 units / kg of amylase and 1000-3000 units / kg of saccharifying enzyme to the weight of the diluted algae pulp for enzymolysis, after the reaction is completed, adding <5g / 100mL of additives, stirring and mixing evenly; the additives include a pH regulator for adjusting the pH to 7.0-8.0, and the pH regulator is sodium carbonate, phosphate or citrate; S4, homogenization: heating the mixture obtained in S3 to 50-80° C. and transferring it to a high-pressure homogenizer for homogenization at least once; The homogenization pressure is 60-80 MPa, and the homogenization is repeated 1-3 times; S5, sterilization and filling.

2. The preparation method according to claim 1, characterized in that: In S1, the microalgae is any one or more of Chlamydomonas reinhardtii, Chlorella vulgaris, Scenedesmus, Euglena, Spirulina, Dunaliella salina, Microchloropsis pseudochloropsis, and any one or more of the high-yield protein mutant strains of any of the foregoing.

3. The preparation method according to claim 1, characterized in that: In S2, before using a high-pressure homogenizer to break the algae powder / algae mud, water is added to make the algae cell dry matter concentration 50-200 g / L.

4. The preparation method according to claim 1, characterized in that: In S3, during the enzymatic hydrolysis process, water is added to dilute the broken algae slurry until the dry matter content of the microalgae is 10g / L-100g / L and the protein content is ≥1.0g / 100mL; the enzymatic hydrolysis conditions are: reacting at 50±5°C for 45-90min.

5. The preparation method according to claim 1, characterized in that: In S3, the protease is one or a combination of food grade alkaline protease, neutral protease, papain, bromelain, trypsin and pepsin, the amylase is one or a combination of α-amylase and pullulanase, and the saccharifying enzyme is one or a combination of glucoamylase or β-amylase.

6. The preparation method according to claim 1, characterized in that: In S3, the additives also include one or more of an emulsifier, a thickener and a flavoring agent; the emulsifier is one or more of polysorbate, monoglyceride and diglyceride, sucrose fatty acid ester, sorbitan fatty acid ester, sodium / calcium stearoyl lactylate; the thickener is one or more of xanthan gum, maltodextrin, alginate, carrageenan, guar gum, sodium carboxymethyl cellulose, and pectin; the flavoring agent is one or more of chocolate, vanilla essence, mint essence, concentrated fruit juice, acidity regulator, and vegetable oil.

7. The preparation method according to claim 1, characterized in that: In S5, the sterilization conditions are: one or a combination of treatment at 135-150°C for 2-10s, pasteurization at 75-100°C, and treatment at 100-121°C for 10-20 minutes; sterilization is performed before or after filling.

8. A microalgae plant milk beverage, prepared by the preparation method according to any one of claims 1 to 7.

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