1. Preparation of asparagus juice
 (1) Raw material pretreatment:
 Cleaning: Select asparagus, canned asparagus and leftovers from the production of quick-frozen asparagus that are not rotten and deteriorated as raw materials, and strictly wash the raw materials to remove microorganisms, sand, dead leaves and some pesticides attached to the surface of the raw materials to ensure the product. Quality stability.
 Add 0.2‰ multi-surface active agent, 0.8~1‰ vitamin C and 0.3‰ citric acid to the cleaning solution to improve the cleaning effect and remove copper and other heavy metals in the bactericide.
 Fixing: After cleaning, the raw materials should be fixed with 0.3‰ citric acid water at 95°C for three minutes. This fixing process can maintain the original juice color and inactivate the activity of enzymes to prevent browning and microbial spoilage in subsequent processing steps. , while removing part of the bitterness.
 (2) Crushing and juicing:
 Crushing: The materials after finishing and cooling should be crushed in time, the crushing fineness is 1~15mm, and 0.03‰ citric acid, 0.15% sodium ascorbate and 0.005% dipping enzyme are added during the crushing process to effectively decompose the colloid in asparagus. Substances, reduce viscosity and improve juice yield. The crushing process should adopt the cold crushing method, which can reduce the damage to vitamin C in the crushing process.
 Juicing: The raw materials are crushed with a crusher and then juiced with a screw juicer. The juicing process should also be kept at low temperature, which can maintain strong pectinase activity and improve the clarity of asparagus juice. The squeezed juice was filtered through a 150-mesh ternary vibrating screen.
(3) Enzymatic hydrolysis clarification: Pump the filtered juice (55~65℃) into the enzymatic hydrolysis tank quickly, add 0.003% natural clarifying agent of STERM layer potential of composite dispersed particles, stir and mix well, stand still for 1.5~2 hours, It mainly removes colloidal unstable components such as tannic acid, protein, resin, wax, etc., and eliminates its effect on the active components in asparagus juice such as alkaloids, glycosides, saponins, terpenes, polysaccharides, amino acids, polypeptides, vitamins, minerals and other components Impact.
 Diatomaceous earth filtration: The asparagus juice clarified by enzymatic hydrolysis, that is, the supernatant, is injected into a diatom filter for filtration. The filter adopts a rotary drum vacuum filter. 900~950mm mercury column, the thickness of the pre-hanging diatomite layer is 4~5cm, the scraper is adjusted to 0.5~0.8 mm, and the filtered asparagus juice is then filtered into a positive pressure diatomite filter for filtration. The technical indicators of asparagus juice are that the transmittance (625nm) is 95.6%, the color value (425nm) is 50%, and the turbidity is 4~5NTU. The precipitation liquid under enzymatic hydrolysis was separated by a decanter centrifuge and then pumped into diatomaceous earth for filtration.
 2. Preparation of papaya juice
 (4) Selection of raw materials: papaya used as raw materials should be more than 80% mature, without insect scars and rotten fruits;
 Peeling: Peel with lye, the concentration of lye is 12 Baume degrees, the temperature is 95-100°C, and the time is 1-1.5 minutes. After peeling, rinse with water in time to remove the residual lye on the surface of the fruit. (5) Cut in half and remove seeds: Cut the peeled papaya in half with a stainless steel knife, and remove the seeds, pedicle and calyx;
 De-astringency: The astringency is removed by soaking in water at 30-32°C, and the time is controlled within 4 hours; Cutting and softening: The pulp is cut into small pieces of uniform size and softened in water at 95-100°C for a time of 3 to 5 minutes. (6) Juicing: Put the softened papaya meat into pieces and put them into a screw-type juicer for juicing. The juice is collected in a stainless steel tank, and the pomace is discharged at the same time. Coarse filtration: filter with a 240-mesh nylon mesh screen to obtain a coarse filtration juice. Ultrafiltration: The papaya juice processed by coarse filtration is subjected to ultrafiltration with a hollow fiber ultrafiltration machine at a pressure of 0.49 MPa. The filter membrane used in this ultrafiltration device is cellulose acetate membrane. The clear juice flows out through the filter membrane and is collected.
 3. Compound fermentation
 (7) Mixing ingredients: Wash the millet and wash it clean and then crush it. Add the prepared asparagus juice, papaya juice and purified water to the mixing tank, start stirring, and slowly add the crushed millet and asparagus. Juice, papaya juice, millet, and purified water in a ratio of 30:10:10:50. Pay attention to the stirring and feeding speed to make them evenly mixed without caking or sinking.
 Cooking: Introduce the base material prepared according to the optimal ingredient ratio into the cooking pot, stir while heating, and cook and gelatinize. Pay attention to controlling the heating and stirring speed to prevent precipitation or sticking to the bottom of the pot. The cooking temperature is selected from 95 to 98 °C And 103 ~ 105 ℃, the holding time was 15, 30, 45, 60 minutes respectively, and the changes of the viscosity value and sugar content value were detected to determine the optimal cooking conditions.
 It can be seen from the above chart that the optimal cooking conditions should be: temperature 103-105 ℃, time 30 minutes;
 (8) Saccharification: After cooking, the temperature can be lowered and saccharified. After reaching the requirement of saccharification temperature, add saccharification agents such as saccharification enzyme and Aspergillus rhizopus, stir evenly, and keep warm for saccharification. At the same time, pay attention to record the changes of sugar content and pH. After reaching the specified requirements, the saccharification can be stopped and the fermentation can be cooled down.
 A. The influence of saccharification temperature and time: the saccharification temperature was taken at 65, 60, and 55°C, respectively, 300 units/g of saccharification enzyme was added, and the saccharification was kept warm, and the change of sugar content and the time to reach the highest sugar content were measured to determine the optimal saccharification temperature and saccharification time. .
 It can be seen from the above chart that the optimal saccharification temperature and saccharification time should be determined as: saccharification temperature 60℃, time 72h;
 B. Influence of saccharifying agent selection: ① saccharifying enzyme ② saccharifying enzyme + root koji ③ root koji ④ middle-temperature distiller's yeast can be used for saccharification test to determine the best saccharifying agent combination. The dosage can be added at 300 units/g according to its saccharification power.
 The best saccharifying agent combination is determined: saccharifying enzyme + root koji
 C. Influence of saccharification agent dosage: According to the ratio of saccharification power of 100, 150, 200, 300, 400 units/g, add saccharification agent to carry out saccharification test, and record the change of sugar content to determine the best ratio.
 Determine the optimal amount of saccharifying agent: 300 units/g
 D. Determine the optimal saccharification conditions by orthogonal test
 On the basis of the previous saccharification experiments, in order to obtain the optimal saccharification conditions, orthogonal tests were carried out on the key process parameters affecting the saccharification effect, such as saccharification temperature, saccharification time, saccharification agent combination, and saccharification agent dosage, respectively, to determine the optimal saccharification conditions.
 Optimum saccharification process parameters: saccharification temperature 60℃, time 72h; saccharification agent: saccharification enzyme + Aspergillus rhizogenes; saccharification agent dosage: 300 units/g.
 (9) Preparation of yeast starter: several yeasts purchased from the market and selected and preserved by the Food Fermentation Research Institute of Yantai University: Yeast No. XYNo109 of Yantai University, New Earth Fragrance Yeast, Angel Fragrance Yeast, Jiuyi Fragrance Yeast, Liangyou Fragrance Yeast, Rice Wine Dry Yeast, use asparagus papaya compound juice, measure the sugar content to 3°Brix, add wort to adjust the sugar content to 7°Brix, respectively inoculate the above yeasts into 100ml asparagus papaya according to the same inoculation amount In the compound juice, the fermentation is carried out under temperature control in a constant temperature incubator, and the fermentation conditions are observed. It is considered that the fermentation of the new earth aroma yeast is better, the acid rise is slow, and the aroma is more harmonious and elegant; the angel aroma yeast ferments faster, but the aroma is single and the ester flavor is too strong; the Jiuyi and Liangyou aroma yeast are The acid rises quickly, and the fragrance is mixed. Finally, Aromania novae was selected as the strain used in this experiment.
 Preservation of strains: The selected aromatizing yeast is firstly preserved in a test tube slant medium made of wort. Adjust the concentration of wort to 7°Bx, pH value of 4.5~5, agar 2%, sterilize at 0.1MPa for 30min, temperature control at 26~28°C, after culturing for 3 days, store at about 4°C, inoculate and transplant once every 3 months .
 Laboratory purebred culture:
 Slanted strain → small triangular flask (250ml, cultured for 24 hours) → large triangular flask (1L, cultured for 18-20 hours) → Karl Fischer flask (15L)
 Workshop purebred culture:
 Karl Fischer flask (15L, cultured for 19 hours) → primary seed tank (100L, cultured for 8-20 hours) → secondary seed tank (1000L, cultured for 8-20 hours) → yeast starter
 Among them, wort is generally used as the medium for the first two stages of culture, and the asparagus papaya compound juice can be directly used as the medium for the last three stages. 10.
 (10) Fermentation: Add 10% asparagus yeast starter to the sterilized base material, and use different fermentation temperatures for fermentation. When the sugar content drops to 15-18Brix, immediately stop the fermentation and sterilize. Do a good job of recording the changes in sugar content, total acid, temperature, and pH value during the fermentation process to determine the best fermentation conditions.
 The best fermentation conditions: the best fermentation temperature is 26 ~ 28 ℃, time 4 ~ 5 days.
 4. Preparation and filling
 (11) Enzymatic hydrolysis clarification: The sterilized fermentation broth (55~65℃) is quickly pumped into the enzymolysis tank, and the temperature is 50~55℃, plus 0.03‰ of ZTC natural clarifying agent, 0.03‰ of fruit Glyase, 0.007‰ silica sol, 0.003‰ tannin and 0.005‰ gelatin, stir well, and then rest for 1.5~2 hours for enzymatic hydrolysis and clarification to eliminate the effective components in the fermentation broth such as alkaloids, glycosides, saponins, terpenes, The effects of polysaccharides, amino acids, peptides, vitamins, minerals and other components.
 Diatomaceous earth filtration: The fermentation broth clarified by enzymatic hydrolysis is put into a diatomaceous earth filter for filtration. The filter adopts a rotary drum vacuum filter. First, coarse filtration is carried out. During the process of hanging the filter, the vacuum degree is 900~950mm. mercury column, the thickness of the pre-hanging diatomite layer is 4~5cm, the scraper is adjusted to 0.5~0.8 mm, the filtered fermentation broth is then filtered into a positive pressure diatomite filter for filtration, and the fermented juice technology after filtration is completed The indicators are, transmittance (625nm) 95.6%, color value (425nm) 50%, turbidity 4~5NTU.
 (12) Deploy: according to consumer preferences, in line with corporate standards, Ph3.8-4.0, sag 8 + 0.5 mainly adjusts the sugar-acid ratio of the beverage, highlights the freshness and coolness of the asparagus and papaya functional beverage, and fully reflects the original characteristics of asparagus juice and papaya juice. The prepared asparagus and papaya functional drink is firstly subjected to ultra-fine filtration: particles and macromolecules of 5-100 nm are filtered by ultra-fine filtration membrane, and the operating static pressure difference is 0.21 MPa to ensure clarity and transparency, and to remove some impurities. Then, the ultra-high temperature instantaneous sterilizer is kept at 121°C for 8-10s for UHT sterilization treatment. After the sterilization is completed, the temperature is immediately lowered to 85-90°C for aseptic filling, packaging and storage.
 The asparagus papaya functional beverage of the present invention is prepared by the method of the present invention.