A kind of brewing method of green spirulina draft beer and spirulina extract

Abstract

The present invention relates to a brewing method of green spirulina draft beer and spirulina extract, and belongs to the technical field of beer brewing. The present invention provides a method for preparing spirulina extract by using brewery equipment, wherein the spirulina extract includes an extract rich in spirulina functional components and a green extract rich in spirulina chlorophyll, and by adding the extract rich in spirulina functional components twice and adding the green extract rich in spirulina chlorophyll once, a naturally deodorized green spirulina draft beer is brewed, which not only has a bright green body, white and delicate foam, long-lasting cup hanging, fresh ocean breath, light hop aroma, mellow taste, soft and smooth, but also has certain nutritional and health effects due to the presence of spirulina functional components. The present invention makes full use of the existing equipment of the brewery, the entire extraction and brewing process is natural and safe, the required materials are simple and easy to obtain, and the cost is low.

Description

Technical Field

[0001] The invention relates to a brewing method of green spirulina draft beer and spirulina extract, in particular to a spirulina extract prepared by using brewery equipment and a naturally deodorized green spirulina draft beer brewed by adding the spirulina extract twice, belonging to the technical field of beer brewing. Background Art

[0002] Beer is the world's largest-selling alcoholic beverage, produced and sold in more than 150 countries and regions. At present, China implements the national beer standard GB4927-2008, which defines beer as: fermented wine containing carbon dioxide, foaming, and low alcohol content, brewed with malt and water as the main raw materials, hops (including hop products), and yeast fermentation; draft beer is defined as beer that is sterilized by other physical methods (mainly membrane filtration) without pasteurization or instantaneous high-temperature sterilization to achieve a certain biological stability.

[0003] Spirulina is a dark green spiral algae plant. It is one of the most nutritious, comprehensive and easily digestible natural green foods discovered so far. The nutritional content of 1 gram of spirulina is equivalent to the total nutritional value of 1,000 grams of various vegetables and fruits. Therefore, the United Nations World Food Association calls it "the most ideal nutrient source in the 21st century", the World Health Organization (WHO) confirms it as "the best health product for mankind in the 21st century", the US Food and Drug Administration (FDA) recognizes it as "one of the best sources of protein", and the National Health Commission of China also recommends it as a "new resource nutritious food". Its protein content is as high as 58.5%~72%, and it is of excellent quality. It contains 17 kinds of amino acids (including 8 essential amino acids that cannot be synthesized by the human body). It combines more than 10 kinds of vitamins, among which β-carotene is the highest. It also contains a variety of trace elements and minerals necessary for the human body and bioactive substances, such as γ-linolenic acid and algae polysaccharides. As a fully natural, high-protein, physiologically active ingredient-rich, nutritious functional food, spirulina has very important nutritional and medical care functions. For example, the β-carotene in it has antioxidant, immune-enhancing, cardiovascular disease prevention and treatment and anti-cancer effects; polysaccharides have anti-radiation and anti-mutation functions, and can inhibit cell proliferation; γ-linolenic acid can stimulate the synthesis of prostaglandins, and is also helpful for arthritis, heart disease, obesity and zinc deficiency; phycocyanin plays an important role in improving the function of human peripheral hematopoietic cells and promoting red blood cell growth, and can be used to treat functional anemia; in addition, it can also regulate human physiological functions, promote cell metabolism, improve lipid metabolism, lower plasma cholesterol, and has significant effects on hypertension, diabetes, liver disease, stomach disease, etc.

[0004] With the improvement of people's living standards, the characteristics of mainstream beer products, such as single color, similar flavor, and bland taste, can no longer meet the psychological needs of modern consumers for nutrition and health care, novelty and difference, and it is difficult to stimulate the desire of consumers to drink again. Therefore, developing new beer varieties with different colors and flavors can meet the multi-level structural needs of consumers. To this end, after successfully launching yellow beer, dark beer, red beer, white beer, and non-alcoholic beer, we have also brewed natural deodorized green spirulina draft beer and analyzed the effective ingredients of spirulina in beer. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a method for brewing green spirulina draft beer and spirulina extract, which mainly utilizes brewery equipment to prepare spirulina extract, and brews natural deodorized green spirulina draft beer by adding spirulina extract twice. The spirulina draft beer brewed by the present invention has a bright green body, white and delicate foam, long-lasting cup hanging, mellow taste, fresh ocean flavor, rich chlorophyll, β-carotene, γ-linolenic acid, high nutritional value and certain health care effects.

[0006] The technical solution of the present invention is as follows:

[0007] A method for brewing green spirulina draft beer comprises the following steps: preparing a green extract rich in spirulina chlorophyll, preparing an extract rich in spirulina functional components, expanding and culturing lager yeast, malt saccharification, wort filtration, wort boiling, wort cooling, wort fermentation, and membrane filtration sterilization. The extract rich in spirulina functional components is added in the lager yeast expansion and culturing stage and before canning when the sugar content of the fermentation liquid drops to 4.0-4.5°P, and the green extract rich in spirulina chlorophyll is added before canning when the sugar content of the fermentation liquid drops to 4.0-4.5°P.

[0008] Preferably, according to the present invention, the green extract rich in spirulina chlorophyll is prepared according to the following method:

[0009] In the filter tank of the pilot saccharification workshop of the brewery, 90-95% food-grade alcohol is added, the tillage machine is turned on, and ultrafine spirulina powder is added, wherein the ultrafine spirulina powder is obtained after freeze-drying and ultrafine grinding, and the mass ratio of the ultrafine spirulina powder to the food-grade alcohol is 1: (4-5), and the mixture is soaked for 72-80 hours. The filter valve of the filter tank sieve plate is opened to filter and obtain the chlorophyll-rich spirulina crude liquid extracted with alcohol, and then the chlorophyll-rich spirulina crude liquid is pumped into the saccharification pot of the pilot saccharification workshop of the brewery, and stirring is started, the temperature is raised to 80-90° C., and the temperature is kept for 15-20 minutes to completely evaporate the food-grade alcohol in the spirulina crude liquid to obtain a pure chlorophyll-rich spirulina liquid, and finally the liquid is pumped to a 0.45 μm membrane filtration system, and after filtration and sterilization, a green extract rich in spirulina chlorophyll can be obtained, which can be stored in a cold storage for standby use.

[0010] Preferably, according to the present invention, the extract rich in the effective components of Spirulina is prepared according to the following method:

[0011] In a saccharification pot of a pilot saccharification workshop of a brewery, distilled water is added to raise the temperature and maintain it at 50-55° C. Superfine spirulina powder is added under stirring, wherein the superfine spirulina powder is obtained by ultrafine grinding after freeze drying, and the mass ratio of the superfine spirulina powder to distilled water is 1: (4-5). Malt powder for beer brewing is added, and the mass ratio of the malt powder to the superfine spirulina powder is 1: (10-12). The mixture is stirred evenly and kept warm for 60-65 minutes to facilitate the protease in the malt powder to decompose the protein in the superfine spirulina powder and the malt powder. After keeping warm for 60-65 minutes, stirring is started, the temperature is raised to 60-65° C., and the mixture is kept warm for 90-95 minutes to facilitate the amylase in the malt powder to decompose the sugars in the superfine spirulina powder and the malt powder to obtain a spirulina crude liquid, and an extract rich in spirulina functional components is obtained after filtering, centrifuging and sterilizing.

[0012] Preferably, according to the present invention, the brewing method of the green spirulina draft beer mentioned above comprises the following specific steps:

[0013] (1) Preparation of green extract rich in chlorophyll of spirulina: Add 90-95% food grade alcohol into the filter tank of the pilot saccharification workshop of the brewery, start the tillage machine, add ultrafine spirulina powder, the ultrafine spirulina powder is obtained by ultrafine grinding after freeze drying, and the mass ratio of the ultrafine spirulina powder to the food grade alcohol is 1: (4-5), soak for 72-80 hours, open the filter valve of the filter tank screen plate, filter to obtain chlorophyll-rich spirulina crude liquid extracted with alcohol, and then pump the chlorophyll-rich spirulina crude liquid into the saccharification pot of the pilot saccharification workshop of the brewery, start stirring, heat to 80-90°C, and keep warm for 15-20 minutes to completely evaporate the food grade alcohol in the spirulina crude liquid to obtain pure chlorophyll-rich spirulina liquid, and finally pump it to a 0.45 μm membrane filtration system, filter and sterilize, and then obtain green extract rich in chlorophyll of spirulina, which can be stored in a cold storage for later use;

[0014] (2) Preparation of extracts rich in spirulina's effective ingredients

[0015] ① Extraction of spirulina functional components: Add distilled water to the saccharification pot of the pilot saccharification workshop of the brewery, heat it up and keep it at 50-55°C, add superfine spirulina powder under stirring, the superfine spirulina powder is obtained after freeze-drying and superfine grinding, the mass ratio of the superfine spirulina powder to distilled water is 1:(4-5), add malt powder for beer brewing, the mass ratio of the malt powder to the superfine spirulina powder is 1:(10-12), stir evenly, keep warm for 60-65 minutes, so that the protease in the malt powder can decompose the protein in the superfine spirulina powder and the malt powder; after keeping warm for 60-65 minutes, start stirring, heat it up to 60-65°C, and keep warm for 90-95 minutes, so that the amylase in the malt powder can decompose the sugars in the superfine spirulina powder and the malt powder, so as to obtain a spirulina crude liquid;

[0016] ② Filtration of the spirulina crude liquid: pump the spirulina crude liquid obtained in step ① into the filter tank of the pilot saccharification workshop of the brewery, and filter it through the sieve plate and wheat bran to obtain the spirulina filtrate;

[0017] ③ Centrifuging the spirulina filtrate: The spirulina filtrate obtained in step ② is transferred to a beer centrifuge and centrifuged at 3000-4000 rpm for 20-25 minutes to obtain the supernatant which is the extract A rich in spirulina functional ingredients;

[0018] ④ Repeat extraction and centrifugation: return the precipitate obtained by centrifugation in step ③ to the saccharification pot, add distilled water, repeat the operation of steps ①②③, and the supernatant obtained by centrifugation is the extract B rich in the effective components of Spirulina;

[0019] ⑤ Refrigeration of the extract rich in the effective components of Spirulina: Evenly mix the extract A and the extract B obtained in step ③ and step ④ to obtain the extract rich in the effective components of Spirulina, and place it in a cold storage for refrigeration;

[0020] ⑥ Instantaneous sterilization of the extract rich in spirulina's functional ingredients: The extract rich in spirulina's functional ingredients is quickly heated to 72-75°C using the instantaneous sterilization equipment equipped by the brewery, and maintained for 15-20 seconds to achieve the effect of instantaneous sterilization, thereby obtaining an extract rich in spirulina's functional ingredients that can be stored at room temperature;

[0021] (3) The following is the expansion of the culture of Saccharomyces cerevisiae shenjiu-2

[0022] The brewer's yeast shenjiu-2 is subjected to a three-level expansion culture in a laboratory and a three-level expansion culture in a brewery yeast expansion culture workshop, and the extract rich in the effective components of Spirulina in step (2) ⑥ is added to the expansion culture medium in the second-level expansion tank of the brewery yeast expansion culture workshop, wherein the amount of the extract rich in the effective components of Spirulina added is 0.06-0.1% of the mass of the wort used for fermentation;

[0023] (4) Maltose

[0024] The malt is crushed by a wet grinder which is most commonly used in modern breweries. The malt includes barley malt. The crushed malt mash is transported to a saccharification pot, and water is added to control the material-water ratio to be 1: (3-4). The malt mash is kept warm at 40-42°C in the saccharification pot for 15-20 minutes. After keeping warm for 15-20 minutes, stirring is turned on, and steam is turned on to raise the temperature to 45-46°C, which is a suitable temperature for β-glucanase in the malt. β-glucanase is added at the same time. The addition of β-glucanase The amount of malt added is 0.1-0.2% of the malt mass to decompose the β-glucan in the malt. Keep it at this temperature for 30-35 minutes; then raise the temperature to 52-53°C and maintain it for 35-40 minutes to use the various proteases contained in the malt to decompose the protein in the malt; then raise the temperature to 65-67°C and maintain it for 90-95 minutes to obtain the maximum amount of fermentable sugar; then slowly raise the temperature to 78°C and maintain it for 10 minutes to obtain saccharified mash;

[0025] (5) Wort filtration

[0026] The saccharified mash obtained in step (5) is pumped into a wort filter tank, filtered and washed to make the wort concentration at 10-11°P;

[0027] (6) Wort boiling

[0028] The wort obtained in step (6) is pumped into a boiling pot and begins to boil, and hops are added three times during the boiling process;

[0029] (7) Wort cooling

[0030] The boiled wort in step (7) is pumped into a vortex sedimentation tank, left to stand for 30 to 35 minutes, and after removing the hot coagulant, cooled to 6 to 9°C through a plate heat exchanger, and sterile air is introduced into the wort through a venturi tube to ensure that the oxygen content in the cold wort is 8 to 10 mg / L, thereby obtaining the wort for fermentation, which is then transported to a fermentation tank; while the wort is being cooled, the yeast solution of the bottom fermentation brewer's yeast shenjiu-2 cultured in step (3) is added to the wort for fermentation through a yeast adder, wherein the amount of yeast in the bottom fermentation brewer's yeast shenjiu-2 solution is 8×10 6 ~1×10 7 CFU / mL, inoculation volume is 15-20%;

[0031] (8) Wort fermentation

[0032] After adding yeast, open fermentation is carried out, and the main fermentation temperature is controlled at 9°C. When the sugar content of the fermentation liquid drops to 4.0-4.5°P, the extract rich in spirulina functional ingredients in step (2) ⑥ is added in an amount of 0.15-0.20% of the mass of the wort used for fermentation. At the same time, the green extract rich in spirulina chlorophyll in step (1) is added in an amount of 0.07-0.1% of the mass of the wort used for fermentation. The fermentation tank is closed, the pressure of the fermentation tank is controlled at 0.14 MPa, and the fermentation temperature is continued to be controlled at 9°C. The pressure is maintained for 7-8 days. The diacetyl content of the fermentation liquid is detected. When the diacetyl content drops below 0.08 mg / L, the temperature is lowered, first at 0.3°C / hour to 5°C, maintained for 24 hours, and then at 0.1°C / hour to -1-0°C. The yeast mud and cold condensate at the bottom of the fermentation tank are removed. The beer is kept at this temperature for 7 days. The beer is mature and ready for filtration.

[0033] (9) Membrane filtration sterilization

[0034] The temperature, yeast count, turbidity, viscosity and β-glucan content of the beer to be filtered obtained in step (9) are detected. When the values ​​are not higher than 0°C, 5 yeasts / 100mL, 0.5EBC, 1.5 mPa·s and 100mg / L respectively, the beer to be filtered is pumped to a 0.45 μm membrane filtration system for filtration and sterilization to obtain Spirulina draft beer.

[0035] Preferably according to the present invention, the malt in step (4) further comprises wheat malt, and the mass of the wheat malt is 40-45% of the total mass of the barley malt and the wheat malt.

[0036] The invention relates to spirulina draft beer prepared according to the method.

[0037] Preferably according to the present invention, the characteristic effective ingredient of the Spirulina draft beer is γ-linolenic acid.

[0038] Application of gamma-linolenic acid in the identification of Spirulina draft beer.

[0039] The beer on the market that does not contain spirulina but adds green pigments and pretends to be spirulina beer does not contain γ-linolenic acid, the unique effective ingredient in spirulina. Therefore, the γ-linolenic acid content can be tested by gas chromatography to identify whether it is green beer brewed with spirulina.

[0040] An extract rich in spirulina functional ingredients is prepared according to the following method:

[0041] In a saccharification pot of a pilot saccharification workshop of a brewery, distilled water is added to raise the temperature and maintain it at 50-55° C. Superfine spirulina powder is added under stirring, wherein the superfine spirulina powder is obtained by ultrafine grinding after freeze drying, and the mass ratio of the superfine spirulina powder to distilled water is 1: (4-5). Malt powder for beer brewing is added, and the mass ratio of the malt powder to the superfine spirulina powder is 1: (10-12). The mixture is stirred evenly and kept warm for 60-65 minutes to facilitate the protease in the malt powder to decompose the protein in the superfine spirulina powder and the malt powder. After keeping warm for 60 minutes, stirring is started, the temperature is raised to 60-65° C., and the mixture is kept warm for 90-95 minutes to facilitate the amylase in the malt powder to decompose the sugars in the superfine spirulina powder and the malt powder to obtain a spirulina crude liquid, and an extract rich in spirulina functional components is obtained after filtering, centrifuging and sterilizing.

[0042] Preferably, according to the present invention, the extract rich in the effective components of Spirulina is prepared according to the following method:

[0043] ① Extraction of spirulina functional components: Add distilled water to the saccharification pot of the pilot saccharification workshop of the brewery, heat it up and keep it at 50-55°C, add superfine spirulina powder under stirring, the superfine spirulina powder is obtained after freeze-drying and superfine grinding, the mass ratio of the superfine spirulina powder to distilled water is 1:(4-5), add malt powder for beer brewing, the mass ratio of the malt powder to the superfine spirulina powder is 1:(10-12), stir evenly, keep warm for 60-65 minutes, so that the protease in the malt powder can decompose the protein in the superfine spirulina powder and the malt powder; after keeping warm for 60-65 minutes, start stirring, heat it up to 60-65°C, and keep warm for 90-95 minutes, so that the amylase in the malt powder can decompose the sugars in the superfine spirulina powder and the malt powder, so as to obtain a spirulina crude liquid;

[0044] ② Filtration of the spirulina crude liquid: pump the spirulina crude liquid obtained in step ① into the filter tank of the pilot saccharification workshop of the brewery, and filter it through the sieve plate and wheat bran to obtain the spirulina filtrate;

[0045] ③ Centrifuging the spirulina filtrate: The spirulina filtrate obtained in step ② is transferred to a beer centrifuge and centrifuged at 3000-4000 rpm for 20-25 minutes to obtain the supernatant which is the extract A rich in spirulina functional ingredients;

[0046] ④ Repeat extraction and centrifugation: return the precipitate obtained by centrifugation in step ③ to the saccharification pot, add distilled water, repeat the operation of steps ①②③, and the supernatant obtained by centrifugation is the extract B rich in the effective components of Spirulina;

[0047] ⑤ Refrigeration of the extract rich in the effective components of Spirulina: Evenly mix the extract A and the extract B obtained in step ③ and step ④ to obtain the extract rich in the effective components of Spirulina, and place it in a cold storage for refrigeration;

[0048] ⑥ Instantaneous sterilization of the extract rich in spirulina's effective ingredients: The extract rich in spirulina's effective ingredients is quickly heated to 72-75°C using the instantaneous sterilization equipment equipped by the brewery and maintained for 15-20 seconds to achieve the effect of instantaneous sterilization, thereby obtaining the extract rich in spirulina's effective ingredients that can be stored at room temperature.

[0049] In the present invention, the fishy smell in the extract rich in spirulina functional components is effectively reduced. The fishy smell of spirulina mainly comes from spirulina protein, especially phycocyanin and phycobiliprotein, etc. Due to the degradation of protease, the fishy smell is effectively reduced.

[0050] A green extract rich in spirulina chlorophyll is prepared according to the following method:

[0051] In the filter tank of the pilot saccharification workshop of the brewery, 90-95% food-grade alcohol is added, the tillage machine is turned on, and ultrafine spirulina powder is added, wherein the ultrafine spirulina powder is obtained after freeze-drying and ultrafine grinding, and the mass ratio of the ultrafine spirulina powder to the food-grade alcohol is 1: (4-5), and the mixture is soaked for 72-80 hours. The filter valve of the filter tank sieve plate is opened to filter and obtain the chlorophyll-rich spirulina crude liquid extracted with alcohol, and then the chlorophyll-rich spirulina crude liquid is pumped into the saccharification pot of the pilot saccharification workshop of the brewery, and stirring is started, the temperature is raised to 80-90° C., and the temperature is kept for 15-20 minutes to completely evaporate the food-grade alcohol in the spirulina crude liquid to obtain a pure chlorophyll-rich spirulina liquid, and finally the liquid is pumped to a 0.45 μm membrane filtration system, and after filtration and sterilization, a green extract rich in spirulina chlorophyll can be obtained, which can be stored in a cold storage for standby use.

[0052] The technical features of the present invention are as follows:

[0053] The present invention firstly utilizes the existing equipment of the brewery to prepare the natural and safe spirulina extract, then uses the lager beer most commonly produced by the brewery as the base beer, and brews the green spirulina draft beer with natural deodorization by adding the spirulina extract, wherein the spirulina extract comprises an extract rich in spirulina functional components and a green extract rich in spirulina chlorophyll, which can protect the unique green color of spirulina on the one hand, remove the fishy smell at the same time, and improve the food safety of the spirulina extract on the other hand. At the same time, the present invention adds the extract rich in spirulina functional components twice, the first time is added in the yeast expansion culture stage, the second time is added before the canning when the sugar content of the fermented liquid is reduced to 4.0~4.5°P, and the green extract rich in spirulina chlorophyll is also added at the same time, so that the spirulina functional components and yeast act synergistically, and the residual fishy smell in the spirulina extract is removed while providing nutrients to the yeast, and the natural green color of spirulina is guaranteed to the greatest extent, and finally, the characteristic functional components of spirulina draft beer are determined by comparative brewing, sensory evaluation, and analysis and detection, so as to identify the possible green spirulina beer pretended by the unconventional addition of green pigment.

[0054] Beneficial effects:

[0055] The invention provides a spirulina extract prepared by brewery equipment, wherein the spirulina extract comprises an extract rich in spirulina functional components and a green extract rich in spirulina chlorophyll, and by adding the extract rich in spirulina functional components twice and adding the green extract rich in spirulina chlorophyll once, a naturally deodorized green spirulina draft beer is brewed, which not only has a bright green body, white and delicate foam, and a long-lasting cup hanging, but also has a fresh ocean flavor, a light hop aroma, a mellow taste, and a soft and smooth taste, and the presence of the spirulina functional components gives the beer certain nutritional and health effects. The invention makes full use of the existing equipment of the brewery, realizes the on-site preparation of the green extract rich in spirulina chlorophyll and the extract rich in spirulina functional components, only uses food-grade alcohol and food-grade enzyme preparations, avoids other toxic reagents such as acetone and methanol commonly used in extracting spirulina functional components, and gives full play to the synergistic effect of spirulina and yeast, further removes a small amount of fishy components of spirulina, and the entire extraction and brewing process is natural and safe, the required materials are simple and easy to obtain, and the cost is low, which is an innovative technology worthy of promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a picture of the green Spirulina draft beer brewed in Example 1.

[0057] Figure 2 The radar chart of sensory evaluation of the Spirulina draft beer brewed in Example 1 and the control draft beer. DETAILED DESCRIPTION

[0058] The present invention is described in detail below through specific embodiments. The experimental methods designed in the embodiments are all routine experimental operations in the art unless otherwise specified; the raw materials involved in the embodiments are all common commercially available products unless otherwise specified. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, other embodiments obtained by ordinary technicians in the art without making creative work belong to the protection scope of the present invention.

[0059] The bottom fermentation brewer's yeast shenjiu-2 involved in the embodiment is the brewer's yeast carried on Shenzhou 9 by Shandong Institute of Light Industry (the predecessor of Qilu University of Technology) in 2012. It has been screened, purified and preserved for 2-3 years under the unique environmental conditions of ultra-weightlessness, strong ultraviolet rays and ultra-low temperature in space. It needs to be expanded and cultured according to the steps in the embodiment to meet the specific requirements of the present invention.

[0060] Saccharomyces cerevisiae Saccharomyces cerevisiae )shenjiu-2, deposited in the China General Microbiological Culture Collection Center on March 17, 2023, with the deposit address at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, with the deposit number: CGMCC NO.26830.

[0061] Example 1 (5000 liters of spirulina draft beer with a brewing temperature of 12°P was used as the experimental group, and draft beer without spirulina extract and with the same brewing process as the control group)

[0062] A method for brewing green spirulina draft beer, comprising the following steps:

[0063] 1. Use brewery equipment to prepare green extracts rich in spirulina chlorophyll and extracts rich in spirulina's functional ingredients

[0064] (1) Malt crushing: Weigh 10 kg of malt, sprinkle a small amount of water into it with a sprinkler, stir it evenly with your hands to make the malt moist but not sticky, pour the malt into a double-roll crusher to obtain well-crushed malt powder (the bran is relatively intact to facilitate the subsequent filtering process);

[0065] (2) Soaking Spirulina: Select freshly cultivated Spirulina, soak it in dilute salt water (NaCl concentration is 20g / L) to remove the fishy smell for 24 hours, and then rinse it with clean water;

[0066] (3) Preparation of ultrafine spirulina powder: freeze-dry the soaked, deodorized and cleaned spirulina at -60°C, and then grind it to 1000 meshes in a water-cooled ultrafine grinder to obtain ultrafine spirulina powder;

[0067] (4) Preparation of green extract rich in spirulina chlorophyll: Add 400 kg of 95% food grade alcohol into a 500-liter filter tank in the pilot saccharification workshop of the brewery, start the tillage machine, add 100 kg of the ultrafine spirulina powder obtained in step (3), and soak for 72 hours. Since chlorophyll is soluble in alcohol, open the filter valve of the filter tank sieve plate to filter out the chlorophyll-rich spirulina crude liquid extracted with alcohol, and then pump the chlorophyll-rich spirulina crude liquid into a 500-liter saccharification pot in the pilot saccharification workshop of the brewery, and start stirring. , raising the temperature to 80°C and keeping the temperature for 20 minutes to completely evaporate the food-grade alcohol in the chlorophyll-rich spirulina crude liquid (at normal temperature and pressure, the boiling point of alcohol is about 78°C, and the chlorophyll in spirulina is mainly chlorophyll A, whose content is 2-3 times that of other plant chlorophyll, and its boiling point is 1032.1°C), to obtain alcohol-free chlorophyll-rich spirulina liquid, and finally pumping it to the 0.45μm membrane filtration system of the brewery, after filtering and sterilization, a green extract rich in spirulina chlorophyll can be obtained, which can be stored in a cold storage for standby use;

[0068] (5) Extraction of the effective components of spirulina: In a 500-liter saccharification pot in the pilot saccharification workshop of the brewery, add 400 kg of distilled water and heat it to 50° C., add 100 kg of the ultrafine spirulina powder prepared in step (3) under stirring, add 10 kg of malt powder prepared in step (1), stir evenly, and keep the temperature at 50° C. for 60 minutes to facilitate the protease in the malt powder to decompose the protein in the ultrafine spirulina powder and the malt powder; after keeping the temperature for 60 minutes, start stirring, heat the temperature to 65° C., and keep the temperature for 90 minutes to facilitate the amylase in the malt powder to decompose the sugars in the ultrafine spirulina powder and the malt powder to obtain a spirulina crude liquid; during the heating process from 50 to 65° C., the fishy smell in the spirulina crude liquid is further reduced (the fishy smell of spirulina mainly comes from spirulina protein, especially phycocyanin and phycobiliprotein, etc., and the fishy smell is gradually reduced due to the degradation of protease);

[0069] (6) Filtration of Spirulina Crude Liquid: The Spirulina crude liquid from step (5) is pumped into a 500-liter filter tank in the pilot saccharification workshop of the brewery, filtered through a sieve plate and wheat bran to obtain Spirulina filtrate, and the filtered wheat bran is sold together with the spent grains of the brewery;

[0070] (7) Centrifugation: The spirulina filtrate obtained in step (6) is transferred to a beer centrifuge and centrifuged at 3000 rpm for 20 minutes. The obtained supernatant is the extract A rich in the effective components of spirulina.

[0071] (8) Repeat extraction and centrifugation: The precipitate obtained by centrifugation in step (7) (instead of the ultrafine spirulina powder) is returned to the 500-liter saccharification pot, 200 kg of distilled water is added, and the operations of steps (5), (6), and (7) are repeated. The supernatant obtained by centrifugation is the extract B rich in the effective components of spirulina. The obtained precipitate is sold together with the spent grains of the brewery;

[0072] (9) Refrigeration of the extract rich in the effective ingredients of Spirulina: The extract A and the extract B obtained in step (7) and step (8) are mixed together and stirred evenly to obtain the extract rich in the effective ingredients of Spirulina, which is then placed in a cold storage for later use.

[0073] (10) Instantaneous sterilization of the extract rich in the effective ingredients of Spirulina: If the extract rich in the effective ingredients of Spirulina needs to be stored for a long time, the extract rich in the effective ingredients of Spirulina can be quickly heated to 72°C and maintained for 15 seconds using the instantaneous sterilization equipment equipped by the brewery to achieve the effect of instantaneous sterilization. The extract rich in the effective ingredients of Spirulina can be obtained and can be stored at room temperature with a shelf life of 180 days.

[0074] 2. Expansion of the fermentation yeast shenjiu-2

[0075] Laboratory expansion culture stage: In order to obtain the appropriate amount of bottom fermentation brewer's yeast shenjiu-2 bacterial liquid for brewing spirulina draft beer, it is necessary to carry out step-by-step expansion culture. First, the bottom fermentation brewer's yeast shenjiu-2 stored in a refrigerator at 0-4℃ is transferred to a sterile liquid test tube culture medium containing 10mL of wort. The transfer process is carried out in a clean bench. To ensure the sterility of the environment, turn on the ultraviolet lamp for sterilization 30 minutes before the transfer work begins, and pay attention to maintaining aseptic operation during the transfer process to avoid contamination of miscellaneous bacteria. After the transfer process is completed, it is placed in a constant temperature shaker at 25℃ and cultured for 24 hours; then, according to the previous steps, the yeast cultured in the test tube is transferred to a 1L triangular flask containing 500mL of wort that has been sterilized in advance; after the transfer is completed, it is placed in a constant temperature shaker at 20℃ and cultured for 24 hours, and then transferred to a pre-sterilized cassette containing 25L of wort, and cultured at a constant temperature of 15℃ for 24 hours for standby. Before each transfer, the yeast count should be checked with a microscope, and the yeast count should reach 8×10 6 ~1×10 7 The transfer can be done at around CFU / mL.

[0076] The yeast expansion workshop stage of the brewery: The yeast expansion workshop of the brewery adopts a three-stage expansion method. The 25 liters of yeast in the laboratory expansion stage cartridge are pressed into the first expansion tank containing 100 liters of sterile wort by sterile air. The temperature is controlled at 12°C for 24 hours. During this period, sterile air is introduced for 10 minutes every 3 hours. Then, the 100 liters of yeast are pressed into the second expansion tank containing 400 liters of sterile wort by sterile air. At the same time, 5 kg of the extract rich in spirulina active ingredients that has been instantaneously sterilized in step 1 (10) is added (the purpose is to achieve the synergistic effect of the spirulina active ingredient extract and the yeast solution. The former can provide a large amount of amino acids for the yeast solution). Acid and other nutrients to ensure the growth, development and reproduction of yeast, while the latter can remove the remaining fishy components in the former through adsorption and metabolic activities, and further remove the fishy smell), control the temperature at 10°C and maintain it for 36 hours. During this period, sterile air is introduced for 10 minutes every 3 hours (with the intermittent introduction of sterile air, even if there is a little fishy component in the yeast expansion tank, it will be discharged to the outside of the tank through the exhaust pipe); finally, use a thoroughly sterilized yeast addition pump to pump 400L of yeast liquid into a three-stage expansion tank containing 1000L of sterile wort, control the temperature at 7°C and maintain it for 48 hours. During this period, sterile air is introduced for 20 minutes every 3 hours until it is pumped into a 5000L beer fermentation tank. As in the laboratory expansion culture stage, the number of yeast needs to be detected under a microscope before each tank transfer. When the number of yeast reaches 8×10 6 ~1×10 7 CFU / mL or so can be transferred to the tank.

[0077] 3. Preparation of Wort

[0078] (1) Raw material crushing: The malt is crushed by the wet crusher most commonly used in modern breweries. The specific operation process is to lift 900 kg of malt (including 360 kg of wheat malt and 540 kg of barley malt) to the malt temporary storage bin through the elevator, and pump 40°C water into the malt temporary storage bin through the mash pump below to ensure that the malt is evenly soaked. After soaking for 15 minutes, the moisture content of the malt surface can increase by about 30%, which increases the toughness of the bran and gradually activates the various enzymes in the malt. After the soaking, the malt passes through the feed roller and enters the crushing roller with a roller spacing of only 0.45 mm. After crushing, the bran is almost undamaged, which is particularly beneficial for the subsequent wort filtration (because the bran is the natural loose layer for wort filtration), and the wheat grain contents are squeezed and separated from the bran smoothly and without resistance, which is beneficial to improve the utilization rate of malt.

[0079] (2) Malt saccharification: The crushed malt mash is transported to the saccharification pot, and the 40°C hot water used to clean the wet mill is also pumped into the saccharification pot. The material-water ratio is controlled at about 1:3.8. The saccharification pot is kept at 40°C for 20 minutes, which is conducive to the extraction of various enzymes in the malt. After keeping warm for 20 minutes, the stirring is turned on and the steam is turned on to raise the temperature to 46°C, which is the suitable temperature for β-glucanase in the malt. At the same time, 0.8 kg of β-glucanase is added. In this way, the β-glucanase contained in the malt itself and the added The β-glucanase and β-glucanase can work together to promote the complete decomposition of β-glucan in malt, avoiding clogging of the 0.45 μm filter membrane during membrane filtration in the subsequent step 5. Keep warm at this temperature for 30 minutes; then increase the temperature to 52°C and maintain for 40 minutes to utilize the various proteases contained in the malt to decompose the protein in the malt; then increase the temperature to 65°C and maintain for 90 minutes to obtain the maximum amount of fermentable sugars; then slowly increase the temperature to 78°C and maintain for 10 minutes to obtain saccharified mash.

[0080] (3) Wort filtration: Pump the above saccharified mash into the wort filtration tank, let it stand for 15 minutes, and perform wort reflux. When the wort is clear and transparent, formally filter it into the boiling pot. When the spent grains are about to emerge, start washing the spent grains. The washed wort also flows into the boiling pot. Repeat washing the spent grains twice until the sugar content of the mixed wort in the boiling pot is about 10.5°P.

[0081] (4) Boiling wort: After the mixed wort fills the pot, start boiling. Add hops during the boiling process. The boiling time is 70 minutes. After the 10th minute of boiling, add 0.8 kg of Qingdao Dahua hop pellets. After the 30th minute of boiling, add 1.2 kg of Qingdao Dahua hop pellets. After the 60th minute of boiling, add 1 kg of Czech Saaz hop pellets. After the boiling is completed, measure the wort concentration. It should be between 10.7 and 12.3°P (to ensure compliance with the national beer standard GB4927-2008). The amount of wort is about 5,000 liters.

[0082] (5) Wort cooling: The boiled wort is pumped into a cyclone settling tank and allowed to stand for 30 minutes. After the heat coagulants are removed, the wort is cooled to 6-9°C through a plate heat exchanger. At the same time, sterile air is introduced into the wort through a venturi tube to ensure that the oxygen content in the cold wort is 8-10 mg / L. While the wort is cooling, 1000 liters of the bottom fermentation brewer's yeast shenjiu-2 cultured in step 2 is added through a yeast feeder (containing 5 kg of spirulina active ingredient extract, accounting for about 0.08% of the weight of the cold wort).

[0083] 4. Fermentation of Spirulina Draft Beer

[0084] After adding yeast, the cold wort in step 3 (6) begins to ferment in the fermentation tank in an open state, and the main fermentation temperature is controlled at 9°C. When the sugar content of the fermentation liquid drops to 4.3°P, 10 kg of the extract rich in spirulina functional ingredients that has been instantaneously sterilized in step 1 (10) (accounting for about 0.16% of the weight of the fermentation liquid) and 5 kg of the green extract rich in spirulina chlorophyll that has been sterilized by 0.45 μm membrane filtration in step 1 (4) (accounting for about 0.08% of the weight of the fermentation liquid) are accurately and quantitatively added by a pump. The purpose of adding at this time is to allow the amino acids in the extract rich in spirulina functional ingredients to participate in the post-fermentation process of beer, provide nutrition and power for yeast fermentation, and ensure that the chlorophyll, lutein, phycocyanin and other pigment components in the spirulina chlorophyll extract give spirulina beer the classic green color. In addition, since the fermentation tank has not been sealed and pressure maintained at this time, , there is no resistance when pumping spirulina extract, and it is easier to achieve), start to close the fermentation tank, control the pressure of the fermentation tank at 0.14MPa, and continue to control the fermentation temperature at 9℃. Keep the pressure for about 7 days, and start to detect the diacetyl content of the fermentation liquid. When its content drops below 0.08mg / L, start to cool down, first cool down to 5℃ at 0.3℃ / hour, and keep it for 24 hours (at this time, the precipitated bottom fermentation brewer's yeast shenjiu-2 can be discharged from the bottom of the fermentation tank for the production of the next batch of spirulina beer), and then cool down to -1~0℃ at 0.1℃ / hour, and then completely remove the yeast mud and condensed solids at the bottom of the fermentation tank (at this time, the precipitated bottom fermentation brewer's yeast shenjiu-2 at the bottom of the fermentation tank can be pumped into a special yeast storage tank for the production of the next batch of spirulina beer), keep it at this temperature for 7 days, the beer is mature and ready to be filtered.

[0085] 5. Membrane Filtration of Spirulina Draft Beer

[0086] The temperature, yeast count, turbidity, viscosity and β-glucan content of the beer to be filtered in step 4 are detected. When the values ​​are not higher than 0°C, 5 yeasts / 100mL, 0.5 EBC, 1.5 mPa·s and 100 mg / L respectively, the beer to be filtered is pumped to a 0.45 μm membrane filtration system. After filtration and sterilization, a spirulina draft beer with a bright green body, white and delicate foam, long-lasting cup hanging, mellow taste and a fresh ocean flavor can be obtained (see Figure 1 ).

[0087] Physical and chemical indicators of Spirulina draft beer:

[0088] The physical and chemical indicators of the spirulina draft beer brewed according to the above method and the control draft beer without spirulina and with the same other processes are shown in Table 1. These mandatory national standard inspection items all meet the technical requirements of the national standard GB4927-2008 and meet the national standards for premium beer.

[0089] Table 1 Physical and chemical indexes of Spirulina draft beer and control draft beer

[0090]

[0091] Functional ingredients of Spirulina draft beer:

[0092] The effective components of the spirulina draft beer brewed in the example, the control draft beer without spirulina and with the same other processes, and the control draft beer without spirulina but with green pigment added were analyzed, wherein chlorophyll and β-carotene were detected by spectrophotometry, and γ-linolenic acid was analyzed by gas chromatography. The results are shown in Table 2.

[0093] Table 2 Effective components of Spirulina draft beer and control draft beer (mg / L)

[0094]

[0095] As can be seen from Table 2, the natural deodorized green spirulina draft beer brewed by the present invention contains functional ingredients such as chlorophyll, β-carotene, and γ-linolenic acid, while the control draft beer without spirulina does not have these functional ingredients. The control draft beer without spirulina but with green pigment contains a small amount of chlorophyll and β-carotene, the functional ingredients of spirulina, but does not have γ-linolenic acid. Therefore, γ-linolenic acid can be identified as the main functional indicator component of spirulina draft beer, which can be used as an identification method for spirulina draft beer.

[0096] Sensory evaluation of Spirulina draft beer:

[0097] (1) Sensory evaluation criteria

[0098] The wine is bright green in color, with white and delicate foam that lingers in the cup for a long time. It has a fresh ocean scent, a light hop aroma, and a mellow, soft and smooth taste.

[0099] (2) Sensory evaluation

[0100] Seven beer judges with rich experience in sensory tasting conducted sensory tasting on spirulina draft beer and control draft beer without spirulina from five aspects: appearance, aroma, flavor, taste and overall performance. The evaluation was based on the evaluation form of the American Beer Judge Certificate Program (BJCP). The total score was 50 points, including 3 points for appearance, 12 points for aroma, 20 points for flavor, 5 points for taste and 10 points for overall performance. The specific scores and beer evaluations are shown in Table 3, and the sensory tasting radar chart of spirulina draft beer and control draft beer without spirulina is shown in Figure 2 .

[0101] Table 3 Beer sensory tasting scores and evaluation

[0102]

[0103] from Figure 2 It can be seen that seven beer judges with rich experience in sensory tasting gave sensory tasting scores of 40.9 and 39.7 for the spirulina draft beer and the control draft beer without spirulina, both reaching the level of "excellent, requires minimal improvement", indicating that the naturally deodorized green spirulina draft beer is an excellent product.

[0104] Embodiment 2:

[0105] A method for brewing green spirulina draft beer is different from that of Example 1 in that: in step 3, 900 kg of barley malt is used to prepare wort, and the other steps are the same as those of Example 1.

[0106] Identification of Spirulina Draft Beer:

[0107] Since spirulina draft beer has not been pasteurized or sterilized at high temperature, but has been sterilized by a 0.45μm membrane filtration system at low temperature, it tastes fresh and is more nutritious and has health benefits. In addition, the beer is attractively bright green, which is very eye-catching. Therefore, there are many counterfeiters on the market who use cooked beer to impersonate draft beer, and even add green pigments to pass off inferior products as genuine ones. In this regard, based on many years of production and research and development, we can identify it from the following two aspects:

[0108] (1) For draft beer that has not been pasteurized or sterilized at high temperature, the various enzyme systems in the beer body remain active, and the sucrose invertase in the beer can decompose sucrose into glucose. Take 10mL of the beer to be tested in a 150mL test tube, add 2mL of sucrose solution with a concentration of 250g / L, and immerse one end of the glucose identification test paper in it. If the test paper changes color and the color is darker, it can be judged that the beer is draft beer; if the test paper does not change color, it can be judged that the beer is cooked beer.

[0109] (2) As shown in Table 2, although beer without spirulina and with green pigments contains a small amount of chlorophyll and β-carotene, the effective ingredients of spirulina, it does not contain γ-linolenic acid. Therefore, γ-linolenic acid can be identified as the main indicator of the effectiveness of spirulina draft beer and can be used as a method for identifying spirulina draft beer.

[0110] The invention uses existing brewery production equipment to conduct relevant research on the extraction of spirulina functional ingredients during the research and development of spirulina draft beer, and optimizes the adding method of spirulina extract, namely, adding the extract rich in spirulina functional ingredients during yeast expansion and before sealing the fermentation tank, and adding the green extract rich in spirulina chlorophyll at the same time when adding the extract rich in spirulina functional ingredients for the second time.

[0111] During the development of Spirulina draft beer, the inventors found that:

[0112] If 5 kilograms of the extract rich in spirulina functional ingredients added for the first time are mixed with cold wort before fermentation begins, and are pumped into the fermentation tank together for fermentation, the prepared spirulina unroasted beer has a heavier fishy smell, which has a serious impact on the beer mouthfeel. It is speculated that the reason for this phenomenon is that the present invention adds the extract rich in spirulina functional ingredients when yeast is expanded, mainly using yeast to remove the fishy smell in the extract, the loose structure of yeast has an adsorption effect on fishy smell substances, and the multiple enzymes produced by yeast metabolism react with fishy smell substances and are converted into no fishy smell substances, and the nutrients in the extract can promote the growth of yeast equally, increase its growth advantage, and inhibit the growth of miscellaneous bacteria, and high concentration and high activity yeast can further enhance the deodorization effect. But if added before fermentation begins, the yeast concentration in the fermented liquid is lower than the yeast expansion liquid, and the main effect of yeast metabolism is wort fermentation, and the fishy smell in the extract can not be effectively removed, thereby affecting the quality of finished product unroasted beer.

[0113] If the first added 5 kg of extract rich in Spirulina's effective ingredients is added during the wort boiling stage, even if it is added at the end of the boiling stage, the high temperature environment of the boiling stage will still destroy the nutrients in the extract, resulting in a waste of Spirulina's nutrients, and the fishy smell of Spirulina cannot be completely removed.

[0114] If 5 kg of green extract rich in spirulina chlorophyll is mixed with cold wort before fermentation, and pumped into the fermentation tank for fermentation, the green color of the prepared spirulina draft beer is lighter and the green characteristics are not obvious. It is speculated that the reason may be that during the main fermentation stage, the yeast is very active and the yeast has a strong adsorption effect on the pigment, which directly affects the apparent green characteristics of the spirulina draft beer.

[0115] If 5 kg of green extract rich in spirulina chlorophyll is added before membrane filtration, the solid components in the green extract will cause the brewery membrane filtration system to be blocked, increasing maintenance costs and further increasing production costs. The present invention adds green extract rich in spirulina chlorophyll before sealing the fermenter, and the yeast activity is not strong and the pigment adsorption capacity is weak in the fermentation stage after sealing. In the cooling stage after sealing, the solid matter in the green extract is precipitated at the bottom of the fermenter together with the yeast mud and the condensed solids and discharged, which will neither affect the apparent green characteristics of the spirulina draft beer nor block the membrane filtration system.

Claims

1. A method for brewing green spirulina draft beer, characterized in that the steps include: The steps of preparing a green extract rich in spirulina chlorophyll, preparing an extract rich in spirulina functional ingredients, expanding and culturing lager yeast, malt saccharification, wort filtration, wort boiling, wort cooling, wort fermentation, and membrane filtration sterilization, wherein the extract rich in spirulina functional ingredients is added during the lager yeast expansion and culturing stage and before canning when the sugar content of the fermentation liquid drops to 4.0-4.5°P, and the green extract rich in spirulina chlorophyll is added before canning when the sugar content of the fermentation liquid drops to 4.0-4.5°P; The extract rich in the effective components of Spirulina is prepared specifically according to the following method: ① Extraction of spirulina functional components: Add distilled water to the saccharification pot of the pilot saccharification workshop of the brewery, heat it up and keep it at 50-55°C, add superfine spirulina powder under stirring, the superfine spirulina powder is obtained after freeze-drying and superfine grinding, the mass ratio of the superfine spirulina powder to distilled water is 1:(4-5), add malt powder for beer brewing, the mass ratio of the malt powder to the superfine spirulina powder is 1:(10-12), stir evenly, keep warm for 60-65 minutes, so that the protease in the malt powder can decompose the protein in the superfine spirulina powder and the malt powder; after keeping warm for 60-65 minutes, start stirring, heat it up to 60-65°C, and keep warm for 90-95 minutes, so that the amylase in the malt powder can decompose the sugars in the superfine spirulina powder and the malt powder, so as to obtain a spirulina crude liquid; ② Filtration of the spirulina crude liquid: pump the spirulina crude liquid obtained in step ① into the filter tank of the pilot saccharification workshop of the brewery, and filter it through the sieve plate and wheat bran to obtain the spirulina filtrate; ③ Centrifuging the spirulina filtrate: The spirulina filtrate obtained in step ② is transferred to a beer centrifuge and centrifuged at 3000-4000 rpm for 20-25 minutes to obtain the supernatant which is the extract A rich in spirulina functional ingredients; ④ Repeat extraction and centrifugation: Return the precipitate obtained by centrifugation in step ③ to the saccharification pot, add distilled water, and repeat the operation in the order of steps ①-③. The supernatant obtained by centrifugation is the extract B rich in the effective components of Spirulina. ⑤ Refrigeration of the extract rich in the effective components of Spirulina: Evenly mix the extract A and the extract B obtained in step ③ and step ④ to obtain the extract rich in the effective components of Spirulina, and place it in a cold storage for refrigeration; ⑥ Instantaneous sterilization of the extract rich in spirulina's functional ingredients: The extract rich in spirulina's functional ingredients is quickly heated to 72-75°C using the instantaneous sterilization equipment equipped by the brewery, and maintained for 15-20 seconds to achieve the effect of instantaneous sterilization, thereby obtaining an extract rich in spirulina's functional ingredients that can be stored at room temperature; The green extract rich in spirulina chlorophyll is prepared according to the following method: In a filter tank of a pilot saccharification workshop of a brewery, 90-95% food-grade alcohol is added, a tillage machine is turned on, and ultrafine spirulina powder is added, wherein the ultrafine spirulina powder is obtained by ultrafine grinding after freeze drying, and the mass ratio of the ultrafine spirulina powder to the food-grade alcohol is 1: (4-5), and the mixture is soaked for 72-80 hours, and the filter valve of the filter tank screen plate is opened to filter and obtain a chlorophyll-rich spirulina crude liquid extracted with alcohol, and then the chlorophyll-rich spirulina crude liquid is pumped into a saccharification pot of a pilot saccharification workshop of a brewery, stirring is started, the temperature is raised to 80-90° C., and the temperature is kept for 15-20 minutes to completely evaporate the food-grade alcohol in the spirulina crude liquid to obtain a pure chlorophyll-rich spirulina liquid, and finally the liquid is pumped to a 0.45 μm membrane filtration system, and after filtration and sterilization, a green extract rich in spirulina chlorophyll is obtained, which is stored in a cold storage for later use; The lager beer yeast is Saccharomyces cerevisiae ( Saccharomyces cerevisiae )shenjiu-2, was deposited in the China General Microbiological Culture Collection Center on March 17, 2023, with the deposit address at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, with the deposit number: CGMCC NO.26830.

2. The brewing method according to claim 1, characterized in that: The specific steps are as follows: (1) Preparation of green extract rich in chlorophyll of spirulina: Add 90-95% food grade alcohol into the filter tank of the pilot saccharification workshop of the brewery, start the tillage machine, add ultrafine spirulina powder, the ultrafine spirulina powder is obtained by ultrafine grinding after freeze drying, and the mass ratio of the ultrafine spirulina powder to the food grade alcohol is 1: (4-5), soak for 72-80 hours, open the filter valve of the filter tank screen plate, filter to obtain chlorophyll-rich spirulina crude liquid extracted with alcohol, and then pump the chlorophyll-rich spirulina crude liquid into the saccharification pot of the pilot saccharification workshop of the brewery, start stirring, heat to 80-90°C, and keep warm for 15-20 minutes to completely evaporate the food grade alcohol in the spirulina crude liquid to obtain pure chlorophyll-rich spirulina liquid, and finally pump it to a 0.45 μm membrane filtration system, filter and sterilize, and then obtain green extract rich in chlorophyll of spirulina, which is stored in a cold storage for later use; (2) Preparation of extracts rich in spirulina's effective ingredients ① Extraction of spirulina functional components: Add distilled water to the saccharification pot of the pilot saccharification workshop of the brewery, heat it up and keep it at 50-55°C, add superfine spirulina powder under stirring, the superfine spirulina powder is obtained after freeze-drying and superfine grinding, the mass ratio of the superfine spirulina powder to distilled water is 1:(4-5), add malt powder for beer brewing, the mass ratio of the malt powder to the superfine spirulina powder is 1:(10-12), stir evenly, keep warm for 60-65 minutes, so that the protease in the malt powder can decompose the protein in the superfine spirulina powder and the malt powder; after keeping warm for 60-65 minutes, start stirring, heat it up to 60-65°C, and keep warm for 90-95 minutes, so that the amylase in the malt powder can decompose the sugars in the superfine spirulina powder and the malt powder, so as to obtain a spirulina crude liquid; ② Filtration of the spirulina crude liquid: pump the spirulina crude liquid obtained in step ① into the filter tank of the pilot saccharification workshop of the brewery, and filter it through the sieve plate and wheat bran to obtain the spirulina filtrate; ③ Centrifuging the spirulina filtrate: The spirulina filtrate obtained in step ② is transferred to a beer centrifuge and centrifuged at 3000-4000 rpm for 20-25 minutes to obtain the supernatant which is the extract A rich in spirulina functional ingredients; ④ Repeat extraction and centrifugation: Return the precipitate obtained by centrifugation in step ③ to the saccharification pot, add distilled water, and repeat the operation in the order of steps ①-③. The supernatant obtained by centrifugation is the extract B rich in the effective components of Spirulina. ⑤ Refrigeration of the extract rich in the effective components of Spirulina: Evenly mix the extract A and the extract B obtained in step ③ and step ④ to obtain the extract rich in the effective components of Spirulina, and place it in a cold storage for refrigeration; ⑥ Instantaneous sterilization of the extract rich in spirulina's functional ingredients: The extract rich in spirulina's functional ingredients is quickly heated to 72-75°C using the instantaneous sterilization equipment equipped by the brewery, and maintained for 15-20 seconds to achieve the effect of instantaneous sterilization, thereby obtaining an extract rich in spirulina's functional ingredients that can be stored at room temperature; (3) Expansion of lager beer yeast Saccharomyces cerevisiae shenjiu-2 The brewer's yeast shenjiu-2 is subjected to a three-level expansion culture in a laboratory and a three-level expansion culture in a brewery yeast expansion culture workshop, and the extract rich in the effective components of Spirulina in step (2) ⑥ is added to the expansion culture medium in the second-level expansion tank of the brewery yeast expansion culture workshop, wherein the amount of the extract rich in the effective components of Spirulina added is 0.06-0.1% of the mass of the wort used for fermentation; (4) Maltose The malt is crushed by a wet grinder which is most commonly used in modern breweries. The malt includes barley malt. The crushed malt mash is transported to a saccharification pot, and water is added to control the material-water ratio to be 1: (3-4). The malt mash is kept warm at 40-42°C in the saccharification pot for 15-20 minutes. After keeping warm for 15-20 minutes, stirring is turned on, and steam is turned on to raise the temperature to 45-46°C, which is a suitable temperature for β-glucanase in the malt. β-glucanase is added at the same time. The addition of β-glucanase The amount of malt added is 0.1-0.2% of the malt mass to decompose the β-glucan in the malt. Keep it at this temperature for 30-35 minutes; then raise the temperature to 52-53°C and maintain it for 35-40 minutes to use the various proteases contained in the malt to decompose the protein in the malt; then raise the temperature to 65-67°C and maintain it for 90-95 minutes to obtain the maximum amount of fermentable sugar; then slowly raise the temperature to 78°C and maintain it for 10 minutes to obtain saccharified mash; (5) Wort filtration The saccharified mash obtained in step (5) is pumped into a wort filter tank, filtered and washed to make the wort concentration at 10-11°P; (6) Wort boiling The wort obtained in step (6) is pumped into a boiling pot and begins to boil, and hops are added three times during the boiling process; (7) Wort cooling The boiled wort in step (7) is pumped into a vortex sedimentation tank, left to stand for 30 to 35 minutes, and after removing the hot coagulant, cooled to 6 to 9°C through a plate heat exchanger, and sterile air is introduced into the wort through a venturi tube to ensure that the oxygen content in the cold wort is 8 to 10 mg / L, thereby obtaining the wort for fermentation, which is then transported to a fermentation tank; while the wort is being cooled, the yeast culture of the brewer's yeast shenjiu-2 expanded in step (3) is added to the wort for fermentation through a yeast adder, wherein the number of yeasts in the brewer's yeast shenjiu-2 culture is 8×10 6 ~1×10 7 CFU / mL, inoculation volume is 15-20%; (8) Wort fermentation After adding yeast, open fermentation is carried out, and the main fermentation temperature is controlled at 9°C. When the sugar content of the fermentation liquid drops to 4.0-4.5°P, the extract rich in spirulina functional ingredients in step (2) ⑥ is added in an amount of 0.15-0.20% of the mass of the wort used for fermentation. At the same time, the green extract rich in spirulina chlorophyll in step (1) is added in an amount of 0.07-0.1% of the mass of the wort used for fermentation. The fermentation tank is closed, the pressure of the fermentation tank is controlled at 0.14 MPa, and the fermentation temperature is continued to be controlled at 9°C. The pressure is maintained for 7-8 days. The diacetyl content of the fermentation liquid is detected. When the diacetyl content drops below 0.08 mg / L, the temperature is lowered, first at 0.3°C / hour to 5°C, maintained for 24 hours, and then at 0.1°C / hour to -1-0°C. The yeast mud and cold condensate at the bottom of the fermentation tank are removed. The beer is kept at this temperature for 7 days. The beer is mature and ready for filtration. (9) Membrane filtration sterilization The temperature, yeast count, turbidity, viscosity and β-glucan content of the beer to be filtered obtained in step (9) are detected. When the values ​​are not higher than 0°C, 5 yeasts / 100mL, 0.5EBC, 1.5 mPa·s and 100mg / L respectively, the beer to be filtered is pumped to a 0.45 μm membrane filtration system for filtration and sterilization to obtain Spirulina draft beer.

3. The brewing method according to claim 2, characterized in that: The malt in step (4) also includes wheat malt, and the mass of the wheat malt is 40-45% of the total mass of the barley malt and the wheat malt.

4. A spirulina draft beer prepared according to the brewing method of claim 1.

5. The spirulina draft beer according to claim 4, characterized in that: The characteristic effective ingredient of the spirulina draft beer is gamma-linolenic acid.

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