Fermented juice and method for preparing the same

Abstract

The application discloses a fermented fruit juice with the effect of reducing high uric acid and a preparation method thereof, and comprises the following steps: step one, obtaining fruit wine after fruit juice fermentation, and obtaining de-alcohol fruit juice by removing alcohol from the fruit wine; step two, inoculating lactic acid bacteria into the de-alcohol fruit juice to perform lactic acid fermentation, and obtaining the fermented fruit juice; the lactic acid bacteria comprises lactobacillus helveticus CICC6064 and / or lactobacillus paracasei CICC20292. The fruit juice prepared by the fermentation process disclosed in the application not only retains the metabolic products of the yeast fermentation except for alcohol, but also increases the biomass and improves the content of apple polyphenol monomers through lactic acid bacteria fermentation, so that the fermented apple juice has the effects of rich taste and nutrition and reducing high uric acid, and has the innovation in the field of functional development of ordinary fruit juice.

Description

Technical Field

[0001] This invention specifically relates to a fermented fruit juice and its preparation method. Background Technology

[0002] As people's living standards continue to improve, diseases caused by unreasonable dietary habits and unhealthy lifestyles are becoming increasingly common. Therefore, regulating uric acid levels in the body through diet is of great significance for clinical treatment, and the use of interventional, ordinary foods to replace traditional drug treatments has become a hot research topic for food scientists.

[0003] my country has abundant fruit resources, but the product range is limited. Expanding the variety of processed fruit products and increasing their added value is imperative. Among these, polyphenols in apples are important bioactive substances. Researchers have conducted in-depth studies on the physiological characteristics of apple polyphenol monomers, revealing that apple polyphenol monomers such as chlorogenic acid, catechins, gallic acid, and quercetin have significant effects on alleviating symptoms of hyperuricemia. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a fermented fruit juice and its preparation method, which removes components in the fruit juice that affect uric acid, and prepares a fermented fruit juice product rich in yeast, lactic acid bacteria metabolites, polyphenols and probiotics, thereby giving ordinary fruit juice the effect of lowering uric acid and increasing the added value of apples.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing fermented fruit juice, comprising:

[0007] Step 1: After the fruit juice is fermented, fruit wine is obtained. The fruit wine is then deethanolerated to obtain dealcoholized fruit juice.

[0008] Step 2: Inoculate the dealcoholized fruit juice with lactic acid bacteria to carry out lactic acid fermentation;

[0009] The lactic acid bacteria mentioned include Lactobacillus helveticus CICC6064 and / or Lactobacillus casei CICC20292.

[0010] Optionally, the volume ratio of *Lactobacillus helveticus* CICC6064 to *Lactobacillus casei* CICC20292 is 2:1.

[0011] Optionally, the inoculation amount of lactic acid bacteria is 2-6%, the fermentation temperature of lactic acid fermentation is 33-37℃, and the fermentation time is 18-24h.

[0012] Optionally, the inoculation amount of lactic acid bacteria is 5%, the fermentation temperature of lactic acid fermentation is 34℃, and the fermentation time is 22h.

[0013] Optionally, step one specifically includes: fermenting the fruit juice with brewer's yeast CICC1027 for 6-7 days to obtain fruit wine, and then removing the ethanol from the fruit wine by vacuum rotary evaporation to obtain dealcoholized fruit juice.

[0014] Optionally, the fruit juice is fermented with Saccharomyces cerevisiae CICC1027 for 6-7 days to obtain fruit wine, specifically including a microbial concentration of 10. 8 A seed suspension was prepared by adding CFU / mL of Saccharomyces cerevisiae CICC1027 to the juice; the seed suspension was then inoculated into the juice at a 4% inoculation rate and fermented at 28°C for 6–7 days.

[0015] Optionally, the vacuum rotary evaporation for ethanol removal specifically includes: removing ethanol from fruit wine under vacuum conditions of -0.9 kPa, evaporation time of 45 min, and evaporation temperature of 35°C to obtain de-alcoholized fruit juice.

[0016] Optionally, the juice is apple juice, and its preparation includes: soaking apple pieces in ascorbic acid water for 15 minutes and then juicing them; then heating the apple juice at 90°C for 15 seconds to deactivate polyphenol oxidase; and finally filtering it after it has been allowed to stand at room temperature to obtain apple juice.

[0017] A fermented fruit juice, wherein the fermented fruit juice is prepared by the method for preparing fermented fruit juice with the effect of lowering uric acid as described in this invention.

[0018] Optionally, a post-acidification treatment may also be performed, specifically including: heating the fermented juice in a water bath at 58°C and adding 40 mg / L Nisin and / or 40 mg / L ε-polylysine.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] For the modern fruit juice industry, this invention proposes to add lactic acid bacteria capable of degrading uric acid and its precursors to dealcoholized apple juice obtained through yeast fermentation and vacuum rotary evaporation for further fermentation. Compared to the original fruit juice, yeast fermentation converts glucose in the juice into ethanol, which is then removed, eliminating components in the original juice that cause abnormal uric acid levels. Simultaneously, the fermented apple juice is rich in metabolites from yeast fermentation. Further fermentation with lactic acid bacteria, which have uric acid-lowering effects, further increases metabolites, polyphenol monomer content, and probiotic activity, ultimately producing a non-alcoholic lactic acid bacteria fermented fruit juice that is flavorful, nutritious, and has the effect of lowering high uric acid levels. This invention is highly innovative in the functional processing of ordinary fruit juice, improving the utilization rate and added value of apple processing while endowing ordinary fruit juice with uric acid-lowering effects. Detailed Implementation

[0021] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0022] This invention relates to a fermented fruit juice with uric acid-lowering effects and its preparation method. The specific preparation method includes: First, screening 30 probiotic strains through uric acid degradation, acid and bile salt tolerance, and artificial gastrointestinal fluid to obtain two lactic acid bacteria strains with good gastrointestinal adaptability, fermentability, and uric acid-lowering effects. Second, using fruit juice, especially apple juice, as raw material, yeast fermentation is used to bioconvert the sugar in the juice to obtain fruit wine. Then, ethanol is removed using a rotary evaporator to obtain a dealcoholized fermented fruit juice. This juice is rich in yeast fermentation metabolites and reduces the impact of sugar in the juice on uric acid production, while also removing ethanol that affects uric acid content. Finally, the two selected lactic acid bacteria strains are added to the dealcoholized juice after optimal addition ratio. Lactic acid fermentation is then carried out based on the yeast-fermented juice rich in yeast metabolites after ethanol removal, resulting in a live-culture lactic acid fermented fruit juice with high biomass, high polyphenol monomers, and high viable cell count. The live-culture lactic acid fermented fruit juice is then acidified, or pasteurized to obtain a sterilized lactic acid fermented fruit juice.

[0023] The fruit juice produced by the above-disclosed fermentation process retains the metabolic products of yeast fermentation except for ethanol, and increases biomass and apple polyphenol monomer content through lactic acid bacteria fermentation, resulting in fermented apple juice that is rich in taste and nutrition and has the effect of lowering uric acid. This invention is innovative in the field of functional development of ordinary fruit juice.

[0024] This invention uses freshly squeezed apple juice as raw material. Yeast fermentation reduces the sugar content of the juice to obtain apple cider. Ethanol is then removed using a rotary evaporator to eliminate substances that increase uric acid levels, resulting in dealcoholized apple juice. Single-factor experiments and orthogonal optimization experiments were used to optimize the lactic acid bacteria fermentation process of the apple juice. The viable bacteria count and total phenol content of the fermented apple juice were used as evaluation indicators. The physicochemical properties of the fermented apple juice under these optimized conditions were then measured. Finally, the obtained viable bacteria fermented apple juice was fed to mice for in vivo experiments.

[0025] By adding selected compound lactic acid bacteria to ferment and dealcoholize apple juice, and using the metabolites of yeast-fermented apple juice as a base, further fermentation with lactic acid bacteria produces a fermented fruit juice rich in metabolites, polyphenol monomers, and active probiotics, which has the effect of lowering uric acid. To observe the effect of the fermented fruit juice on lowering uric acid, a mouse model of hyperuricemia was established, and the effects of consuming the fermented fruit juice on the body weight, serum uric acid, blood urea nitrogen, and creatinine of the mice were observed.

[0026] The specific method is as follows: Apple juice is used as the fermentation raw material. After fermentation with yeast, apple wine is produced. The apple wine is then subjected to de-alcoholization treatment, and the selected compound lactic acid bacteria are added to the de-alcoholized juice for fermentation, thus obtaining live-culture fermented apple juice. The yeast is Saccharomyces cerevisiae CICC1027, and the compound lactic acid bacteria are Lactobacillus helveticus CICC6064 and Lactobacillus casei CICC20292, with a ratio of 2:1.

[0027] Apples are rich in polyphenols and other nutrients. Apple polyphenols have a variety of physiological functions. Polyphenols can lower uric acid levels by reducing serum UA, UREA, and CREA levels, decreasing the conversion of uric acid precursors and the deposition of uric acid in joints, reducing the levels of inflammatory factors, and regulating purine metabolism, thereby preventing the occurrence and development of uric acid and achieving the goal of lowering high uric acid.

[0028] The apples used in this invention were purchased from a farmers' market; the brewer's yeast CICC1027 and 30 strains of lactic acid bacteria were purchased from the laboratory; ascorbic acid was a commercially available reagent. The content of polyphenol monomers was measured using conventional high-performance liquid chromatography.

[0029] Example 1:

[0030] 1. Screening of strains with uric acid-lowering function

[0031] (1) Screening of uric acid-degrading strains

[0032] First, the ability of 30 lactic acid bacteria strains (see Table 1) to degrade purines, nucleotides, and nucleosides was analyzed and determined, and strains that could lower uric acid were screened out. Then, further screening was carried out using acid-resistant, bile-resistant, and artificial gastrointestinal fluids.

[0033] Table 1. Names of 30 lactic acid bacteria strains

[0034]

[0035] Table 2 Results of the purine degradation ability of 30 lactic acid bacteria strains

[0036]

[0037] Table 4. Results of the nucleoside degradation ability of 30 lactic acid bacteria strains

[0038]

[0039] Table 2 shows the degradation rates of xanthine, hypoxanthine, and guanine by the 30 lactic acid bacteria strains. The five strains with the best degradation rates were CICC6247, CICC21805, CICC6005, CICC22227, and CICC6064, all of which were above 50%.

[0040] The nucleotide degradation rates of 30 lactic acid bacteria strains were screened, and the results are shown in Table 3. Among them, CICC23139, CICC20273, CICC22227, CICC6074 and CICC20975 showed significant effects in the degradation of guanylic acid and adenosine monophosphate.

[0041] Nucleotides are broken down into nucleosides by nucleotidases, and nucleosides are further broken down into uric acid by related enzymes. To more comprehensively screen probiotics that lower uric acid, the degradation rate of nucleosides (guanosine and adenosine) was studied, and the results are shown in Table 4. CICC21801 and CICC22184 showed the highest guanosine degradation rates, at 86.41% and 85.38%, respectively. Furthermore, CICC20975, CICC20292, CICC21805, CICC20250, and BNCC194390 showed adenosine degradation rates as high as 100%, while CICC21801 had an adenosine degradation rate of 92.95%.

[0042] Table 5. Survival status of strains under pH 3 conditions.

[0043]

[0044] Table 6. Survival of strains under pH 2.5 conditions

[0045]

[0046] Table 7. Survival of strains under 0.3% bile salt conditions

[0047]

[0048] Table 8. Survival of strains under 0.5% bile salt conditions

[0049]

[0050] Table 9. Survival of bacterial strains under artificial gastrointestinal fluid conditions.

[0051]

[0052] As shown in Table 5, at pH 3.0, the survival rate of all six lactic acid bacteria strains was above 89%, demonstrating excellent acid resistance. Among them, CICC20292, CICC21801, and CICC21805 had survival rates exceeding 98%. As shown in Table 6, at pH 2.5, the survival rate of the strains decreased, with only CICC20292 exhibiting the highest survival rate of 91.59%.

[0053] As shown in Tables 7-8, when the bile salt concentration was 0.3%, CICC6064, CICC20250, CICC20292, and CICC21805 exhibited a survival rate of over 80%; CICC23139 and CICC20975 could not grow in a 0.3% bile salt environment. When the bile salt concentration was 0.5%, CICC6064 and CICC20250 showed the best survival activity, with survival rates of 83.14% and 87.44%, respectively. The six selected lactic acid bacteria strains showed good tolerance to acid and bile salts, and therefore have the potential to exert probiotic properties after entering the body.

[0054] The survival rate of lactic acid bacteria was further studied using simulated gastric and intestinal fluids, and the results are shown in Table 9. The lactic acid bacteria were first grown in simulated gastric fluid for 4 hours to observe their growth and survival rate, and then grown in simulated intestinal fluid for another 4 hours. The results showed that the survival rate of the six lactic acid bacteria strains in simulated gastric fluid reached over 90%, and the survival rate in simulated intestinal fluid all reached over 85%, demonstrating good survival rates.

[0055] In summary, by combining acid and bile salt tolerance and simulated gastrointestinal fluid survival experiments, the optimal lactic acid bacteria CICC6064 Lactobacillus helveticus and CICC20292 Lactobacillus casei can be obtained for subsequent fermentation and deethanolination of apple juice.

[0056] (2) Determination of the ratio of lactic acid bacteria in the compound

[0057] CICC6064 exhibits a good degradation rate for purines, while CICC20292 shows a good degradation rate for nucleosides. To determine the mixing ratio of the two strains, high-performance liquid chromatography was used to detect the consumption of uric acid substrates. The results are shown in Table 10.

[0058] Table 10 Results of the determination of the uric acid degradation capacity of lactic acid bacteria

[0059]

[0060] As shown in Table 10, the optimal ratio of uric acid degradation rate of Lactobacillus helveticus (CICC6064) and Lactobacillus casei (CICC20292) was found to be 2:1.

[0061] (3) Preparation of apple juice

[0062] Fully ripe and unspoiled Luochuan apples are thoroughly washed, cut into pieces, and cored. They are then soaked in 0.08% ascorbic acid water for 15 minutes to inhibit enzymatic browning. Subsequently, the apple pulp is juiced using a juicer and filtered through 80-mesh gauze. The apple juice is then heated at 90°C for 15 seconds to inactivate polyphenol oxidase. After standing at room temperature, it is filtered to obtain clear apple juice for later use.

[0063] (4) Preparation of dealcoholized apple juice

[0064] Saccharomyces cerevisiae CICC1027 was cultured in YPD medium at 28°C and 120 rpm for 24 h in a shaker, while lactic acid bacteria were cultured statically in MRS broth at 37°C for 20 h. Both cultures were passaged twice. Cells were harvested by centrifugation at 8000 rpm for 15 min at 4°C, washed twice with sterile water, and resuspended to a final concentration of 10. 8 The concentration of CFU / mL was then added to apple juice to prepare a seed suspension. Finally, the seed suspension was inoculated into 200 mL of apple juice at a 4% inoculation rate. The initial sugar concentration of the apple juice was 11°Brix. The mixture was then incubated at 28°C for 6-7 days.

[0065] The apple cider after yeast fermentation was subjected to vacuum de-alcoholization treatment. The alcohol was removed by rotary evaporation for 45 minutes under vacuum de-alcoholization conditions of 35℃ and -0.9MPa to obtain de-alcoholized apple juice.

[0066] (5) Optimization of lactic acid bacteria fermentation conditions

[0067] The inoculum size, fermentation time, and fermentation temperature directly affect the flavor, taste, and nutritional value of fermented apple juice, with nutritional value being the primary consideration. Response surface methodology was optimized based on previous experiments; the experimental design is shown in Table 11. The optimal fermentation conditions were determined by evaluating the total phenols and viable cell count of the fermented juice. Table 11: Response Surface Design and Experimental Data

[0068]

[0069] Table 12 Analysis of Variance of Viable Bacterial Count

[0070]

[0071] Note: ** indicates extremely significant difference (p < 0.01); * indicates significant difference (p < 0.05)

[0072] Table 13 Analysis of Variance for Total Phenols

[0073]

[0074] Note: ** indicates extremely significant difference (p < 0.01); * indicates significant difference (p < 0.05)

[0075] Table 11-13 shows that the optimal conditions are a fermentation time of 21.526 h, a fermentation temperature of 34.351 °C, an inoculum size of 4.657%, and an expected viable count of 3.73 × 10⁻⁶. 8CFU / mL, total phenol 1.72 mg / mL. For the convenience of subsequent experiments, the fermentation conditions were modified to fermentation time of 22 h, fermentation temperature of 34 ℃, and inoculum size of 5%.

[0076] To test the reliability of the fitting results, a verification experiment was conducted using modified experimental conditions. The results showed a viable count of 3.66 × 10⁻⁶. 8 The CFU / mL and total phenols were 1.69 mg / mL, which were not significantly different from the predicted values, indicating that the response surface methodology results were reliable.

[0077] (6) Analysis of polyphenol monomers in apple juice fermented by lactic acid bacteria

[0078] The selected lactic acid bacteria CICC6064 and CICC20292 were added to the dehydrogenated apple juice at a ratio of 2:1, and fermentation was carried out at a fermentation temperature of 34℃, a fermentation time of 22h, and an inoculum size of 5%.

[0079] The comparison of polyphenol monomer content before and after juice fermentation is shown in Table 14.

[0080] Table 14 Polyphenol monomer content of apple juice before and after fermentation

[0081]

[0082] Note: Data in the table represent sample mean ± standard deviation; different letters in the same column indicate significant differences (p<0.05).

[0083] As shown in Table 14, after lactic acid bacteria fermentation, the fermented fruit juice contained 43.68 mg / 100 mL of catechin, 18.08 mg / 100 mL of chlorogenic acid, 162.38 mg / 100 mL of gallic acid, and 0.07 mg / 100 mL of quercetin. The content of gallic acid and quercetin in the polyphenol monomers was higher than that in the original fruit juice, suggesting a certain effect in lowering uric acid levels.

[0084] (7) Acidification control after probiotic fermentation of apple juice

[0085] The quality of live-culture fermented apple juice changes rapidly during later storage, greatly affecting consumer acceptance. Fermented apple juice also suffers from post-acidification, which occurs during storage as the microorganisms continue to grow and metabolize, producing lactic acid, causing the acidity of the apple juice to increase and the pH value to decrease, leading to a decline in nutritional components and various sensory qualities.

[0086] To control the post-acidification of live bacteria fermented apple juice, the CICC6064:CICC20292 = 2:1 fermented apple juice was first treated with a water bath heating at 58℃ for 4 minutes. Then, Nisin and ε-polylysine were added to control the post-acidification. The live bacteria fermented juice was stored at room temperature at 25℃.

[0087] Table 15 Changes in post-acidification control properties of mixed-strain fermented apple juice during storage.

[0088]

[0089] Note: Data in the table represent sample mean ± standard deviation; different letters in the same column indicate significant differences (p<0.05).

[0090] Table 15 shows that, under normal storage conditions (25℃), the number of viable bacteria in the fermented fruit juice increased from 7.90 × 10⁻⁶ on the first day. 7 CFU / mL decreased to 5.95 × 10⁻⁶ on day 7. 7 The CFU / mL count in all other groups was lower than that in the control group after one day of storage (p<0.05). During storage at 25℃, the pH value decreased significantly, with the pH value of the fermented apple juice dropping from 3.81 to 3.63, indicating post-acidification and a significant increase in acidity. After 7 days, the pH values ​​of the Nisin 40mg / L and ε-polylysine 40mg / L treatment groups were significantly higher than those of the fermented fruit juice group (p<0.05), and these two treatment groups were able to significantly control the increase in acidity during storage.

[0091] (8) Animal efficacy verification

[0092] Seventy male C57 mice were randomly selected and fed a basic diet for 7 days to adapt. The animals were then randomly divided into 7 groups of 10 mice each according to their body weight. Modeling was performed for 3 weeks using intraperitoneal injection of 300 mg / mL potassium oxonate. At 9:00 AM, the experimental groups were administered the original fruit juice, dealcoholized fruit juice, sterilized lactic acid bacteria fermented fruit juice, and live lactic acid bacteria fermented fruit juice obtained in step (5) by gavage. The control group was treated with an equal volume of distilled water. The treatment group was administered 20 mg / mL allopurinol by gavage at a dose of 0.1 mL / 10 g once daily for 3 consecutive weeks. During this period, all animals had free access to water and food.

[0093] During the experiment, the mice in each group showed good growth and normal activity. Morphological methods were used to observe and analyze the effect on lowering uric acid. The weight gain rate and kidney index of each group of mice are shown in Table 16.

[0094] Table 16. Changes in mouse body weight growth rate and kidney index

[0095]

[0096] Note: Data in the table represent sample mean ± standard deviation; different letters in the same column indicate significant differences (p<0.05).

[0097] As shown in Table 16, the live lactic acid bacteria fermented fruit juice resulted in significantly higher weight gain rate and kidney index in mice compared to the model group (p<0.05).

[0098] Serum uric acid (UA), blood urea nitrogen (UREA), and creatinine (CREA) are important indicators reflecting the body's uric acid metabolism. Lowering UA, UREA, and CREA can reduce high uric acid levels. The effects of different fruit juices on serum uric acid levels in mice are shown in Table 17. The detection method was as follows: serum samples were placed in 2 mL sterile centrifuge tubes, and the three indicators (UA, UREA, and CREA) were measured using a fully automated biochemical analyzer.

[0099] Table 17 Effects of different fruit juices on serum uric acid levels in mice

[0100]

[0101] Note: Data in the table represent sample mean ± standard deviation; different letters in the same column indicate significant differences (p<0.05).

[0102] Table 17 shows that after one month of feeding, the serum UA, UREA, and CREA levels in the model group were significantly higher (p<0.05) than those in the baseline control group, being 1.24 times, 1.89 times, and 1.48 times higher, respectively, indicating that the model group mice exhibited significant hyperuricemia. For mice administered live-cultured lactic acid bacteria fermented fruit juice via gavage, serum UA levels were significantly lower than those in the model group and also lower than those in the baseline control group; serum UREA levels were significantly lower than those in the model group but higher than those in the baseline control group; and CREA levels were lower in both groups but higher than those in the baseline control group. These results indicate that live-cultured lactic acid bacteria fermented fruit juice can regulate serum uric acid levels by reducing uric acid, blood urea nitrogen, and creatinine levels.

[0103] Example 2:

[0104] This embodiment is the same as Embodiment 1, except that the lactic acid bacteria are fermented under the following conditions: fermentation time of 18 hours, fermentation temperature of 33°C, and inoculum amount of 2%.

[0105] The live-culture fermented fruit juice obtained in this example contained 48.05 mg / 100 mL of catechin, 17.91 mg / 100 mL of chlorogenic acid, 155.77 mg / 100 mL of gallic acid, and 0.07 mg / 100 mL of quercetin. The serum UA, UREA, and CREA values ​​of the mice in this example group were 134.68 μmol·L⁻¹. -1 11.93 mmol·L -1 35.26 mmol·L -1 The levels were significantly lower than those in the model group, indicating a certain effect in lowering uric acid.

[0106] Example 3:

[0107] This embodiment is the same as Embodiment 1, except that the lactic acid bacteria are fermented under the following conditions: fermentation time of 24 hours, fermentation temperature of 37°C, and inoculum amount of 6%.

[0108] The live-culture fermented fruit juice obtained in this example contained 47.62 mg / 100 mL of catechin, 17.66 mg / 100 mL of chlorogenic acid, 165.78 mg / 100 mL of gallic acid, and 0.06 mg / 100 mL of quercetin. The serum UA, UREA, and CREA values ​​of the mice in this example group were 145.87 μmol·L⁻¹. -1 12.13 mmol·L -1 36.25 mmol·L -1 The levels were all lower than those in the model group, indicating a certain effect in lowering uric acid.

[0109] The present invention has been described above in conjunction with embodiments thereof. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art, under the guidance of the present invention, shall apply the invention within the scope of protection of the present invention without departing from the spirit and scope of the claims.

Claims

1. A method for preparing fermented fruit juice, characterized in that, include: Step 1: The bacterial concentration is 10. 8 A seed suspension was prepared by adding CFU / mL of Saccharomyces cerevisiae CICC1027 to the juice. The seed suspension was inoculated into the juice at a rate of 4%, and fermented at 28°C for 6-7 days to obtain fruit wine; the ethanol was removed to obtain the dealcoholized juice. Step 2: Inoculate the dealcoholized fruit juice with lactic acid bacteria to carry out lactic acid fermentation; The lactic acid bacteria are Lactobacillus helveticus CICC6064 and Lactobacillus casei CICC20292; the volume ratio of Lactobacillus helveticus CICC6064 to Lactobacillus casei CICC20292 is 2:1; The inoculation amount of lactic acid bacteria is 5%, the fermentation temperature of lactic acid fermentation is 34℃, and the fermentation time is 22h. The juice is also subjected to a post-acidification treatment, which includes: heating the fermented juice in a water bath at 58°C and adding 40 mg / L Nisin and / or 40 mg / L ε-polylysine.

2. The method for preparing fermented fruit juice according to claim 1, characterized in that, The juice is apple juice, and the specific preparation of the apple juice includes: After soaking apple chunks in ascorbic acid water for 15 minutes, juice them. Then, heat the apple juice at 90°C for 15 seconds to deactivate polyphenol oxidase. After standing at room temperature, filter the juice to obtain the final product.

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