CN111227232A

CN111227232A - Preparation method of medlar extract enzyme liquid and product thereof

Info

Publication number: CN111227232A
Application number: CN202010063995.1A
Authority: CN
Inventors: 苏海锋; 林家富
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-01-20
Filing date: 2020-01-20
Publication date: 2020-06-05

Abstract

The invention relates to the technical field of enzyme fermentation, and discloses a preparation method of medlar extract enzyme liquid and a product thereof, wherein the preparation method comprises the following steps: mixing dry and fresh medlar and water, pulping, standing at constant temperature, removing particles through a screen mesh, leaving slurry I, and carrying out ultrasonic treatment on the slurry I to obtain slurry II; adding acetic acid into the slurry II to prepare slurry III, heating the slurry III to boil under the constant temperature condition, refluxing, and then evaporating to remove the acetic acid to obtain slurry IV; sterilizing the slurry IV at high temperature and high pressure, cooling after sterilization, preserving at constant temperature, then inoculating mixed strains, and fermenting under constant temperature and shaking conditions to obtain medlar extract ferment liquid; the medlar extract ferment liquid prepared by the invention has double functions of probiotics and medlar efficacy.

Description

Preparation method of medlar extract enzyme liquid and product thereof

Technical Field

The invention relates to the technical field of enzyme fermentation, in particular to a preparation method of medlar extract enzyme liquid and a product thereof.

Background

Medlar is a rare medicinal material and a tonic, and the traditional Chinese medicine has a long term saying 'medlar health preservation'. The compendium of materia Medica records: medlar, tonifying kidney and producing sperm, nourishing liver and improving eyesight and calming the nerves, has long life, and has the functions of reducing blood sugar, resisting fatty liver and resisting atherosclerosis. The medlar extract is a composite product extracted by medlar serving as a raw material through a certain method, and mainly comprises the following components: carbohydrate, crude fiber, crude fat, crude protein and lycium barbarum polysaccharide, wherein the lycium barbarum polysaccharide consists of 6 monosaccharide components of arabinose, glucose, galactose, mannose, xylose and rhamnose; meanwhile, other medicinal compounds are mostly polysaccharide pigment, vitamin, sterol, glycoside and the like; for example, betaine, carotene, thiamine, riboflavin, niacin, ascorbic acid, nicotinic acid, zeaxanthin, and various amino acids, etc.; meanwhile, the fertilizer contains some elements such as calcium, phosphorus, iron, magnesium, zinc, germanium and the like. Research proves that the medlar extract has the functions of nourishing liver and kidney, replenishing vital essence, improving eyesight, regulating and improving immunity, can improve the level of blood testosterone and has the function of promoting hematopoiesis; also has antiaging, mutation resisting, antitumor, blood lipid reducing, liver protecting, fatty liver resisting, blood glucose reducing, and blood pressure lowering effects.

As is well known, probiotics are a class of active microorganisms that are beneficial to the host, involving a variety of bacteria and fungi including clostridium butyricum, lactic acid bacteria, bifidobacteria, lactobacillus acidophilus, actinomycetes, yeasts, and the like. Researches on modern intestinal microbial populations show that integration of various probiotics can produce exact health efficacy, so that the microecological balance of a host can be improved, and the beneficial effect of adjusting microecological imbalance can be exerted finally. For example, the growth of helicobacter pylori can be inhibited only through the cooperative action of the metabolic activities of various beneficial microorganisms, and gastric ulcer and gastric cancer can be prevented. Therefore, none of these patents can maximize the bioactive function of lycium barbarum, and can also maximize the function of regulating the physiological activity of the human intestinal tract by producing enzymes through submerged fermentation using lycium barbarum as a fermentation substrate.

At present, for the development and utilization of the extract of the medlar, most of the extract of the medlar is solidified into powder to be used as a medicinal health-care product, while the stock solution of the extract of the medlar is directly utilized to be prepared into medicinal oral liquid, the products such as beverages and the like have only a few related products, most of the related products of patents are prepared into beverages by using the extracted polysaccharide of the medlar, and the single polysaccharide of the medlar can not completely exert the biological activity function of the medlar.

In conclusion, a preparation method of the medlar extract enzyme liquid with double functions of probiotics and medlar efficacy and a product thereof need to be researched.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a medlar extract enzyme liquid and a product thereof, so that the medlar extract enzyme liquid has double functions of probiotics and medlar efficacy.

The purpose of the invention is realized by the following technical scheme: a preparation method of medlar extract enzyme liquid comprises the following steps:

1) pretreatment: mixing dry and fresh fructus Lycii with water, pulping, standing at room temperature, filtering to remove particles, leaving slurry I, subjecting the slurry I to ultrasonic treatment for 20-30min to obtain slurry II, wherein the mass ratio of dry and fresh fructus Lycii to water is 4-8%; the dry and fresh medlar is the dry and fresh medlar sold in the market;

2) extraction: adding food-grade acetic acid into the slurry II to prepare slurry III with the mass fraction of the acetic acid being 4-8%, heating the slurry III to boiling under the condition of 120-200 ℃, refluxing for 2-6 hours, and then evaporating to remove the acetic acid to obtain slurry IV;

3) fermentation: sterilizing the slurry IV at high temperature and high pressure, cooling to 30-33 deg.C, preserving at constant temperature, inoculating mixed strains, and fermenting under constant temperature shaking for 3-4 days to obtain fructus Lycii extract ferment liquid.

Further, in the step 1), the standing time is 24 hours, and the mesh number of the screen is 40-80 meshes. The parameters of the step 1) can be adaptively adjusted according to the amount of the specifically pretreated dry and fresh medlar, so that the slurry I has no impurity particles. The ultrasonic treatment directionally breaks the medlar cellulose, converts macromolecular cellulose and polysaccharide contained in medlar into micromolecular oligosaccharide, directionally converts the medlar into single monosaccharide such as glucose and xylose, controls the subsequent microbial fermentation process through the obtained pure monosaccharide, and finally achieves the purposes of maximizing the utilization of medlar, reducing the generation of waste and simultaneously maximizing the concentration of bacteria liquid.

Further, the food grade acetic acid in the step 2) is M22624-500 ML.

Further, in the step 3), the conditions of high-temperature and high-pressure sterilization are as follows: the pressure is 1.5MP, the temperature is 115 ℃ and 121 ℃, and the sterilization time is 15-20 minutes; the fermentation temperature is 28-33 ℃, and the shaking speed is 150-250 rpm. The high-temperature high-pressure sterilization step provides a fermentation environment for the subsequent inoculated strains, and the fermentation temperature and the oscillation speed can be adaptively adjusted according to the types of the subsequently inoculated mixed strains and the content of the slurry IV.

Further, in the step 3), the mixed bacterial strain comprises bacillus subtilis and streptococcus faecalis.

Further, in step 3), the mixed strains comprise subspecies strains of lactobacillus bulgaricus, streptococcus thermophilus, lactobacillus acidophilus, lactobacillus plantarum and lactobacillus casei.

Further, in the step 3), the mixed strain comprises lactobacillus bulgaricus, streptococcus thermophilus, lactobacillus acidophilus, lactobacillus rhamnosus, lactobacillus plantarum, lactobacillus casei subsp casei and bifidobacterium lactis.

Further, in step 3), the mixed strain comprises streptococcus thermophilus, lactobacillus bulgaricus, bifidobacterium infantis, bifidobacterium lactis, bifidobacterium longum, bifidobacterium breve and bifidobacterium bifidum.

Further, in step 3), the mixed strain comprises lactobacillus bulgaricus, streptococcus thermophilus, kefir bacteria, bifidobacterium infantis, bifidobacterium lactis, bifidobacterium longum and bifidobacterium breve.

Further, in the step 3), the mixed strain comprises streptococcus thermophilus, lactobacillus bulgaricus, lactobacillus casei, lactobacillus paracasei, bifidobacterium lactis, bifidobacterium bifidum, lactobacillus acidophilus, lactobacillus plantarum, lactobacillus helveticus and lactobacillus rhamnosus.

Further, in step 3), the kefir bacteria include any four of lactococcus lactis subsp.

Further, the extraction step of the step 2) can adopt ethanol extraction, food-grade ethanol is added into the slurry II to prepare an ethanol medlar suspension with the ethanol concentration of 60%, the ethanol medlar suspension is heated to boiling at the constant temperature of 200 ℃ and then reflows for 6 hours, and then the ethanol in the medlar ethanol extraction solution is removed by evaporation to obtain the ethanol-free medlar extraction solution.

Further, the extraction step of step 2) may adopt hydrothermal extraction: heating the serous fluid II at a constant temperature of 200 ℃ to boil, refluxing for 6 hours, taking 50ml of the obtained medlar hydrothermal extracting solution out, adding water to prepare a medlar hydrothermal extracting solution with the concentration of 3%, then continuously heating at a constant temperature of 200 ℃ to boil, refluxing for 6 hours, and extracting again to obtain the medlar hydrothermal extracting solution.

Further, the medlar extract ferment liquid is mixed with syrup and the like to prepare the medlar deep fermentation ferment beverage. The syrup comprises glucose, fructose syrup, acesulfame potassium, sucralose, aspartame, etc. The addition amount of glucose is 1-5%, the addition amount of high fructose syrup is 0-10%, and the addition amounts of acesulfame potassium, sucralose and aspartame meet the addition range specified in GB 2760. The syrup is also added with an acidity regulator, and the content of the acidity regulator is 2.5-4.5 g/kg. When adding, the acidity regulator is mixed according to the concentration of 2-20%, and the acid liquor is atomized by a special acid spraying device and then is mixed with the mixed feed liquid, and the pH value of the feed liquid is adjusted to 3.5-3.8. The acidity regulator is one or more of citric acid, malic acid, lactic acid, and tartaric acid. The syrup is also added with a thickening agent, and the thickening agent is pectin and comprises one or more of the following components: sodium carboxymethylcellulose, xanthan gum, carrageenan, konjac gum, gellan gum, guar gum and soybean polysaccharide; the syrup is also added with emulsifier such as glyceryl monostearate, sucrose fatty acid ester, diacetyl tartaric acid glyceride, etc. The edible essence is one or more of natural essence, natural equivalent essence and artificially synthesized essence, and the specific types and contents of the above components in the syrup can be adjusted according to the prior art.

All microorganisms used in this scheme, except for Bacillus subtilis and Streptococcus faecalis, are commonly used in the field of yoghurt fermentation. Although some probiotics are used for fermenting the Chinese wolfberry hydrolysate at present, the number of the compound bacteria is not more than 5, usually 2-3, and the invention can finally make the number of the compound bacteria reach 10 after the pretreatment, especially the initial use of acetic acid hydrolysis to maximize the monosaccharide yield. Meanwhile, the bacillus subtilis and the streptococcus faecalis are used as composite strains for fermentation for the first time, and the two composite strains are important strains which are approved by the FDA in the United states and are used for improving the intestinal microorganisms of the human body, and have the effects of effectively improving constipation, increasing digestion and the like.

The key point for solving the problems in the prior art is the pretreatment process in the early stage, so that the main carbohydrate substances utilized by the microorganisms as much as possible are one or two monosaccharides, and the medlar is also utilized to the maximum extent; through the pretreatment process, the acid hydrolysis (acetic acid extraction) of the scheme enables the sugar yield to be maximum, however, the acid used by the common acid hydrolysis is dilute sulfuric acid which is not suitable for being used in the food industry, so the invention combines other pretreatment, firstly uses the acid hydrolysis of acetic acid, and has proper amount of acetic acid which is widely present in foods (such as vinegar, pickled Chinese cabbage and the like) and has no harm to human bodies.

Therefore, the invention firstly utilizes ultrasonic treatment and acetic acid hydrothermal technology to directionally break the medlar cellulose, converts the macromolecular cellulose and polysaccharide contained in medlar into micromolecular oligosaccharide, and directionally converts the medlar into single monosaccharide such as glucose and xylose. Through the obtained pure monosaccharide, the subsequent microbial fermentation process is controlled, and the aims of utilizing the medlar to the maximum degree, reducing the generation of wastes and maximizing the concentration of the bacteria liquid are fulfilled finally.

The invention has the beneficial effects that:

1. according to the scheme, mixed bacteria of bacillus subtilis and streptococcus faecalis are adopted for the first time, the extract of the wolfberry fruit is used as a fermentation substrate, and besides the wolfberry fruit contains abundant wolfberry polysaccharide, abundant mineral elements and amino acids, the wolfberry fruit contains the wolfberry fruit, and the dual bacteria are used as a fermentation enzyme, so that the enzyme can directly supplement normal human physiological flora, inhibit pathogenic bacteria, promote digestion and absorption of nutrient substances, and inhibit generation and absorption of enterogenic toxins, and the purpose of adjusting dysbacteriosis in intestinal tracts is achieved; effectively relieving dyspepsia, inappetence, malnutrition, and diarrhea, constipation and abdominal distention caused by intestinal flora disorder; can inhibit discomfort of human body caused by abnormal fermentation of abnormal bacteria in intestinal tract;

2. in the invention, the extraction of the medlar extract adopts an acetic acid extraction method for the first time except a conventional hydrothermal extraction method and an ethanol precipitation method, and the method improves the content and fruit fragrance of medlar juice, so that more polysaccharides can be decomposed into monosaccharides for being utilized by microorganisms, and simultaneously the freshness of the medlar juice is kept;

3. the invention adopts a mixed type of various microorganism species for fermentation, comprises 5 to 10 different types of microorganisms, obtains more beneficial microorganism enzymes, and is easy to form relatively stable microorganism communities in human bodies as the beneficial microorganism populations are more, thereby having stronger resistance to diseases;

4. the medlar extract is adopted for fermentation, and on the premise of ensuring that probiotics can grow, certain chemical components containing medicinal effects of the medlar extract are not lost, so that the product has double functions of the probiotics and the medlar medicinal effects.

Drawings

FIG. 1 is a schematic flow diagram of the present invention;

FIG. 2 is a chromatogram of the amino acid content analysis of example 1;

fig. 3 is a graph of experimental data for comparative example 1.

Detailed Description

The technical solutions of the present invention are described in further detail below, but the scope of the present invention is not limited to the following.

Example 1 extraction and two-strain fermentation of an ethanol extract of Lycium barbarum

Pretreatment: 200g of dry fresh wolfberry fruit purchased from the market are mixed in a fruit water mass ratio of 6%, pulped (slurried) and extracted at a constant temperature of 35 ℃ for 24 hours, then larger particles are removed by using a 40-80 mesh screen to leave a pulp I, and the pulp I is treated by ultrasonic waves of a 50W ultrasonic instrument for 30 minutes to obtain a pulp II.

Extraction: and (3) preparing the slurry II into slurry III containing 60% of ethanol by mass, placing the slurry III on a rotary electric heating furnace, heating to boil at the constant temperature of 200 ℃, refluxing for 6 hours, and removing the ethanol by using a rotary evaporator to obtain slurry IV. The polysaccharide content of the extract was determined by HPLC and is shown in Table 1 below.

TABLE 1 polysaccharide fraction of ethanol extracted Lycium barbarum

Fermentation: placing the serous fluid IV into a micro fermentation tank, and then sterilizing in a full-automatic autoclave under the sterilization condition of 1.5MP and the sterilization temperature of 115 ℃ for 20 minutes; after the sterilization is finished, placing the serous fluid IV in a constant-temperature water bath kettle to keep the constant temperature of 30 ℃ for about 10 minutes; inoculating a mixed strain of bacillus subtilis and streptococcus faecalis which is activated, rejuvenated and subjected to amplification culture in advance into the sterilized serous fluid IV; finally, placing the inoculated slurry IV in a constant-temperature oscillation incubator, and strictly controlling the fermentation temperature and the oscillation speed in the whole fermentation process, wherein the fermentation temperature is 30 ℃, and the oscillation speed is 220 rpm; and (3) finishing fermentation after 3 days, wherein a product formed in the fermentation tank is the medlar extract enzyme liquid rich in 2 microbial enzymes.

The content of amino acid components in the fermented solution of Lycium barbarum extract and the amino acid analysis pattern are shown in Table 2 and FIG. 2.

TABLE 2 content of amino acid components after fermentation

Description of the drawings: 0.000 indicates that no detection was made at this concentration

Example 2 extraction of acetic acid extract of Lycium barbarum and 5-bacterium mixed fermentation

Slurry II was prepared in accordance with example 1.

Acetic acid extraction: adding food grade acetic acid into slurry II to obtain slurry III with acetic acid concentration of 6%, heating at constant temperature of 200 deg.C to boil, refluxing for 6 hr, and removing acetic acid with rotary evaporator to obtain slurry IV with polysaccharide content shown in Table 3.

TABLE 3 polysaccharide content of Lycium barbarum acetic acid extract

5, mixed fermentation of bacteria: sterilizing the serous fluid IV according to the steps of the embodiment 1, and after the sterilization is finished, placing the serous fluid IV in a constant-temperature water bath kettle to be cooled to 32 ℃, and keeping the constant temperature for 20 minutes; inoculating the mixed strains of activated, rejuvenated and expanded lactobacillus bulgaricus, streptococcus thermophilus, lactobacillus acidophilus, lactobacillus plantarum and lactobacillus casei subspecies casei strains into the sterilized slurry IV in an ultraclean workbench; finally, placing the inoculated slurry IV into a constant-temperature shaking incubator, and strictly controlling the fermentation temperature to be 32 ℃ and the shaking speed to be 220rpm in the fermentation process; and finishing fermentation after 4 days, wherein a product formed in the fermentation tank is the medlar extract ferment liquid rich in 5 probiotic ferment. The content of amino acid components in the fermented solution of lycium barbarum extract is shown in table 4.

TABLE 4 amino acid component content of the fermented extract of Lycium barbarum with 5 kinds of mixed bacteria

Example 3 fermentation of 7 bacteria mix of Lycium barbarum acetic acid extract

In the embodiment, the lycium barbarum acetic acid extract is subjected to submerged fermentation by using mixed bacteria of 7 bacteria. These 7 strains contained two different combinations of strains. I.e., lactobacillus bulgaricus, streptococcus thermophilus, lactobacillus acidophilus, lactobacillus rhamnosus, lactobacillus plantarum, lactobacillus casei subsp. casei, and bifidobacterium lactis, or two types of mixed strains of streptococcus thermophilus, lactobacillus bulgaricus, bifidobacterium infantis, bifidobacterium lactis, bifidobacterium longum, bifidobacterium breve, and bifidobacterium bifidum. The preparation process of the slurry IV in this example is the same as that of example 2, the slurry IV is sterilized according to the steps of example 2, then cooled to the constant temperature of 33 ℃, and then the mixed bacterial liquid of the two types of 7 bacteria which are activated, rejuvenated and expanded is respectively inoculated into the two groups of slurry IV; after inoculation, placing the culture in a constant-temperature shaking incubator, strictly controlling the fermentation temperature to be 33 ℃ and the shaking speed to be 250 rpm; and (3) finishing fermentation after 3 days, wherein products formed in the fermentation tank are two groups of medlar extract enzyme liquid which are respectively rich in two types of 7 probiotic enzyme. The content of amino acid components in the fermented solution of lycium barbarum extract is shown in table 5.

TABLE 5 amino acid component content of Lycium barbarum acetic acid extractive solution after submerged fermentation with 7 kinds of mixed bacteria

Example 4 extraction of hydrothermal extract of Lycium barbarum and 7-bacterium Mixed fermentation

Slurry II was prepared in accordance with example 1.

Performing hydrothermal extraction to obtain a medlar extract: placing the serous fluid II on an electric heating furnace, heating to boil at a constant temperature of 200 ℃, refluxing for 6 hours by using a reflux pipe, taking out 50ml of serous fluid II, adding water to prepare a 3% medlar hydrothermal extracting solution, heating again on the electric heating furnace to a constant temperature of 200 ℃, and refluxing for 6 hours to obtain new serous fluid IV. The polysaccharide content of the extract was measured by HPLC and is shown in Table 6 below.

TABLE 6 polysaccharide content of Lycium barbarum acetic acid extract

And 7, mixed fermentation of bacteria: the slurry IV was sterilized by the procedure of example 1, and after completion of the sterilization, the extract was cooled to a constant temperature of 33 ℃. Respectively inoculating 7 types of activated, rejuvenated and expanded and cultured mixed bacteria liquid into the two groups of sterilized slurry IV in an ultra-clean workbench, finally placing the inoculated slurry IV in a constant-temperature shaking incubator, strictly controlling the fermentation temperature to be 33 ℃ and the shaking speed to be 250rpm in the fermentation process, ending the fermentation after 3 days, and obtaining products formed in the fermenter, namely two groups of medlar enzyme extract liquid respectively rich in 7 types of probiotic enzymes. The amino acid nutrient content of the fermented solution of lycium barbarum extract is shown in table 7.

TABLE 7 amino acid content of the hydrothermal extract of fructus Lycii after submerged fermentation with 7 kinds of mixed bacteria

Example 5 fermentation of 10 bacteria mix of hydrothermal extract of Lycium barbarum

Slurry IV was prepared in accordance with example 4.

Sterilizing the serous fluid IV according to the steps of the example 1, placing the serous fluid IV in a constant-temperature water bath kettle to be cooled to 32 ℃ and keep the temperature unchanged for 30 minutes, and inoculating 10 composite mixed bacteria of two types which are activated, rejuvenated and expanded to the sterilized serous fluid IV in a clean bench; finally, placing the inoculated extract in a constant-temperature shaking incubator, strictly controlling the fermentation temperature to be about 32 ℃ and the shaking speed to be 250 rpm; and finishing fermentation after 3.5 days, wherein a product formed in the fermentation tank is the medlar extract ferment liquid rich in 10 composite probiotic mixed ferment. The content of amino acid components in the fermented solution of lycium barbarum extract is shown in table 8.

TABLE 8 amino acid content of the hydrothermal extract of fructus Lycii after submerged fermentation with 10 kinds of mixed bacteria

Comparative example 1 comparison of the final Strain concentrations after fermentation by three hydrolytic extraction methods

Pretreating the obtained hydrothermal extract of Lycium barbarum with three kinds of pretreatment methods as described in the specification, sterilizing the slurry IV under the conditions of example 1, and cooling the slurry IV to 32 ℃ for 30 minutes after the sterilization is finished; inoculating the activated, rejuvenated and expanded cultured flora in an ultra-clean workbench, then inoculating 5, 7 and 10 different probiotic flora into the sterilized serous fluid IV as described above, and finally placing the inoculated serous fluid IV in a constant-temperature shaking incubator, wherein the fermentation temperature is strictly controlled to be about 32 ℃ and the oscillation speed is 250 rpm; after 3.5 days, the fermentation was terminated and the concentration of the strain was examined by measuring the absorbance OD 600. As shown in fig. 3, the results show that the concentration of the strains in the fermented liquid of the lycium barbarum extract prepared by acetic acid extraction and fermentation with 5 strains, 7 strains and 10 strains respectively is optimal, so as to achieve the strain quantity required by improving the intestinal microbial population.

The foregoing is illustrative of the preferred embodiments of this invention, and it is to be understood that the invention is not limited to the forms disclosed herein, and is not to be construed as limited to the exclusion of other embodiments, and that it may be used in various other combinations, modifications, and environments and may be modified within the scope of the inventive concepts described herein by the above teachings or by the knowledge or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention, which is to be protected by the following claims.

Claims

1. The preparation method of the medlar extract enzyme liquid is characterized by comprising the following steps: the method comprises the following steps:

1) pretreatment: mixing dry and fresh fructus Lycii with water, pulping, standing at room temperature, filtering to remove particles, leaving slurry I, subjecting the slurry I to ultrasonic treatment for 20-30min to obtain slurry II, wherein the mass ratio of dry and fresh fructus Lycii to water is 4-8%;

2. The method of claim 1, wherein: in the step 3), the conditions of high-temperature and high-pressure sterilization are as follows: the pressure is 1.5MP, the temperature is 115 ℃ and 121 ℃, and the sterilization time is 15-20 minutes; the fermentation temperature is 28-33 ℃, and the shaking speed is 150-250 rpm.

3. The method of claim 1, wherein: in the step 3), the mixed strains comprise bacillus subtilis and streptococcus faecalis.

4. The method of claim 1, wherein: in the step 3), the mixed strains comprise subspecies strains of lactobacillus bulgaricus, streptococcus thermophilus, lactobacillus acidophilus, lactobacillus plantarum and lactobacillus casei.

5. The method of claim 1, wherein: in the step 3), the mixed strains comprise lactobacillus bulgaricus, streptococcus thermophilus, lactobacillus acidophilus, lactobacillus rhamnosus, lactobacillus plantarum, lactobacillus casei subspecies casei and bifidobacterium lactis.

6. The method of claim 1, wherein: in the step 3), the mixed strain comprises streptococcus thermophilus, lactobacillus bulgaricus, bifidobacterium infantis, bifidobacterium lactis, bifidobacterium longum, bifidobacterium breve and bifidobacterium bifidum.

7. The method of claim 1, wherein: in step 3), the mixed strain comprises lactobacillus bulgaricus, streptococcus thermophilus, kefir bacteria, bifidobacterium infantis, bifidobacterium lactis, bifidobacterium longum and bifidobacterium breve.

8. The method of claim 1, wherein: in the step 3), the mixed strains comprise streptococcus thermophilus, lactobacillus bulgaricus, lactobacillus casei, lactobacillus paracasei, bifidobacterium lactis, bifidobacterium bifidum, lactobacillus acidophilus, lactobacillus plantarum, lactobacillus helveticus and lactobacillus rhamnosus.

9. The method of claim 7, wherein: in the step 3), the kefir bacteria comprise any four of lactococcus lactis subspecies lactis, lactococcus lactis subspecies cremoris, lactococcus lactis diacetyl subspecies lactis, leuconostoc mesenteroides intestinal membrane subspecies and lactobacillus acidophilus.

10. The fermented wolfberry extract liquid prepared by the method of any one of claims 1-9.