A drinking type of a fermented milk having a flavor and a method for preparing the same

Abstract

The present application relates to the technical field of fermented milk products, in particular to a drinking type flavor fermented milk and a preparation method thereof. The drinking type flavor fermented milk comprises the following components: raw cow milk, concentrated whey protein, sweetening agent, isomaltooligosaccharide, polygonatum extract, sea buckthorn concentrated juice, fermentation strain and water; the fermentation strain is Streptococcus salivarius subsp. thermophilus JMCC16, Lactobacillus delbrueckii subsp. bulgaricus JMCC0018 and Lactococcus lactis JMCC0035. The fermented milk contains more polygonatum polysaccharide and total flavonoids, has stronger antioxidant activity, and the DPPH clearance rate can be up to 80% or more, can quickly relieve muscle fatigue and soreness, and accelerate physical recovery. In addition, the fermented milk has good taste, does not have special bitterness or medicinal taste, can significantly improve exercise endurance, accelerate heart rate recovery, reduce subjective fatigue and reduce post-exercise blood lactic acid level, and is very suitable for daily drinking of general sports people.

Description

Technical Field

[0001] This invention relates to the field of fermented dairy product technology, specifically to a flavored fermented milk for drinking and its preparation method. Background Technology

[0002] With the increasing health awareness of the public, the number of people regularly participating in physical exercise is growing. At the same time, the composition of the sports population has expanded from traditional professional athletes and seasoned endurance enthusiasts to a broader "general sports population"—ordinary sports enthusiasts who participate in diverse activities such as fitness, running, ball games, cycling, mountain climbing, and yoga, primarily at low to moderate intensity, with a frequency of about 2-5 times per week, mainly for health promotion, body management, and stress relief. Unlike professional athletes who pursue extreme performance, the general sports population pays more attention to the comfort during exercise, the speed of fatigue recovery after exercise, and the convenience, taste, and natural properties of products. Fermented milk, as a nutritious and easily digestible food, is very popular among the general sports population.

[0003] Exercise-induced fatigue is a complex phenomenon involving physiological processes such as the accumulation of metabolic waste and increased oxidative stress. Most commercially available fermented milk products contain single-function ingredients, making it difficult to comprehensively address these issues. Furthermore, existing fermented milk products primarily focus on basic nutrition or gut health functions, lacking a systematic design for exercise fatigue recovery, and are significantly insufficient in their application for combating exercise fatigue. Therefore, developing a fermented milk product that can systematically address exercise fatigue, rationally combine plant extracts, and achieve efficient conversion of active ingredients has significant market value. Summary of the Invention

[0004] In view of this, the present invention provides a flavored fermented milk for drinking and a method for preparing the same. This flavored fermented milk can quickly relieve post-exercise fatigue, accelerate physical recovery, and has a good taste that suits the general public's palate.

[0005] To solve the above technical problems, the present invention provides a flavored fermented milk for drinking, comprising the following components by weight percentage: 82%~92% raw milk, 2%~5% concentrated whey protein, 2%~4% sweetener, 4%~6% isomaltooligosaccharide, 0.5%~1.5% Polygonatum extract, 0.3%~0.8% sea buckthorn concentrate, 0.005%-0.02% fermentation strain, and the balance being water; The fermentation strain is a complex of Streptococcus salivarius subsp. thermophilus JMCC16, Lactobacillus delbrueckii subsp. bulgaricus JMCC0018, and Lactococcus fatii JMCC0035.

[0006] Exercise-induced fatigue involves multiple physiological processes, including the accumulation of metabolic products and increased oxidative stress. To systematically address the physiological discomfort caused by exercise fatigue, this invention adds Polygonatum sibiricum extract and sea buckthorn concentrate to the fermented milk matrix. Polygonatum sibiricum extract is rich in polysaccharides and saponins, which can exert antioxidant effects and increase liver glycogen reserves. Sea buckthorn concentrate is rich in sea buckthorn flavonoids and organic acids, which can participate in energy metabolism and enhance antioxidant enzyme activity, thereby alleviating exercise fatigue and accelerating recovery. Furthermore, in addition to the groundbreaking introduction of Polygonatum sibiricum extract and sea buckthorn concentrate, this invention also selects *Streptococcus salivarius* subsp. *thermophilus* JMCC16 and *Lactobacillus delbrueckii* subsp. *bulgaricus* JMCC0018 to ensure proper basal fermentation. The inventors discovered that adding the lactococcus lactis strain JMCC0035, which has antioxidant activity, significantly improves the retention rate of Polygonatum polysaccharides and the content of total flavonoids in fermented milk, thereby synergistically enhancing the antioxidant activity of flavored fermented milk. This is because Lactococcus lactis JMCC0035 can exert its antioxidant activity through mechanisms such as scavenging hydroxyl radicals and protecting cells from oxidative stress damage. Therefore, it is used in combination with Streptococcus salivarius subsp. thermophilus JMCC16 and Lactobacillus delbrueckii subsp. bulgaricus JMCC0018 to improve the conversion efficiency of Polygonatum polysaccharides and sea buckthorn flavonoids.

[0007] It should be noted that the *Streptococcus salivarius* subsp. *thermophilus* JMCC16, *Lactobacillus delbrueckii* subsp. *bulgaricus* JMCC0018, and *Lactococcus lactis* JMCC0035 used in this invention are all publicly known strains. Among them, *Streptococcus salivarius* subsp. *thermophilus* JMCC16 was isolated from traditional fermented dairy products in Inner Mongolia and has been disclosed in patent document CN109536406 A, deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 11672; *Lactobacillus delbrueckii* subsp. *bulgaricus* JMCC0018 was isolated from traditional fermented dairy products in Tibet and has been disclosed in patent document CN107974420A, deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 14425; *Lactococcus fatii* JMCC0035 was isolated from traditional fermented dairy products in Yunnan and has been disclosed in patent document CN118222427 A, deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 24284.

[0008] In conjunction with the first aspect, the viable count of *Streptococcus salivarius* subsp. *thermophilus* JMCC16 in the fermentation strain is 6.4 × 10⁻⁶. 9 CFU / mL ~1.7×10 10The viable count of *Lactobacillus delbrueckii* subsp. bulgaricus JMCC0018 was 1.6 × 10⁻¹¹ CFU / mL. 8 CFU / mL ~8.6×10 8 CFU / mL, the viable count of *Lactococcus lactis* JMCC0035 was 8 × 10⁻⁶. 9 CFU / mL ~2×10 10 CFU / mL.

[0009] In conjunction with the first aspect, the composition, by weight percentage, includes the following: 85% raw milk, 3% concentrated whey protein, 3% sweetener, 5% isomaltooligosaccharide, 1.0% Polygonatum sibiricum extract, 0.5% sea buckthorn concentrate, 0.02% fermentation starter, and the remainder is water; The inoculation amounts of Streptococcus salivarius subsp. thermophilus JMCC16, Lactobacillus delbrueckii subsp. bulgaricus JMCC0018, and Lactococcus faecium JMCC0035 were 0.008%, 0.004%, and 0.008%, respectively.

[0010] In conjunction with the first aspect, the content of Polygonatum polysaccharides in the Polygonatum extract is ≥30%, and the soluble solids in the sea buckthorn concentrate are ≥45%.

[0011] The Polygonatum extract used in this invention is obtained from Polygonatum rhizome through water extraction, concentration, and drying. The content of Polygonatum polysaccharides, calculated as anhydrous glucose, is ≥30%. The determination of Polygonatum polysaccharide content refers to the phenol-sulfuric acid method under the "Polygonatum" entry in the 2020 edition of the Chinese Pharmacopoeia. The concentrated sea buckthorn juice used is obtained from fresh sea buckthorn fruit through pressing, separation, and concentration. The soluble solids (20℃, refractometer method) is ≥45%.

[0012] In conjunction with the first aspect, the sweetener is selected from at least one of granulated sugar, isomaltulose, and crystalline fructose of equal sweetness.

[0013] A second aspect of the present invention provides a method for preparing the above-mentioned beverage-grade flavored fermented milk, comprising the following steps: Under stirring conditions, the concentrated whey protein, sweetener, isomaltooligosaccharide, polygonatum extract and sea buckthorn concentrate are added to the raw milk in sequence according to the formula ratio and stirred evenly to obtain the first emulsion. The first emulsion is preheated, then homogenized, sterilized and cooled to obtain the second emulsion; The fermentation strains were inoculated into the second emulsion in a certain proportion, and fermentation and demulsification were carried out in sequence to obtain the third emulsion. The third emulsion is homogenized a second time, cooled again, and then sequentially filled and refrigerated for ripening to obtain the beverage-grade flavored fermented milk.

[0014] In conjunction with the second aspect, when preparing the first emulsion, the raw milk is preheated to 40-50°C.

[0015] In conjunction with the second aspect, the first emulsion is preheated, then homogenized, sterilized and cooled, specifically as follows: the first emulsion is preheated to 58~62℃, homogenized under a pressure of 17~18MPa, sterilized at 93~98℃ for 300~310s, and then cooled to 36~38℃.

[0016] Preferably, the secondary pressure during homogenization is 5 MPa, and the primary pressure is 17.5 MPa.

[0017] In conjunction with the second aspect, the fermentation conditions are: fermentation at 36~38℃ for 18~22 hours.

[0018] In conjunction with the second aspect, after the fermentation of the second emulsion, when the acidity reaches 68~74°T and the pH ≤ 4.58, demulsification begins 5~15 minutes later.

[0019] In conjunction with the second aspect, the pressure for the second homogenization is 5~10 MPa; The filling temperature is 10~15℃; The specific process of cold-curing is as follows: ripening at 2~6℃ for 12~24 hours.

[0020] The flavored fermented milk provided by this invention contains higher levels of Polygonatum polysaccharides and total flavonoids, exhibiting strong antioxidant activity and a DPPH scavenging rate exceeding 80%. It can quickly alleviate muscle fatigue and soreness, and accelerate physical recovery. In addition to rapidly relieving exercise fatigue, this fermented milk can significantly improve exercise endurance, accelerate heart rate recovery, reduce subjective fatigue, and lower post-exercise blood lactate levels, making it ideal for daily consumption by a wide range of athletes. Furthermore, this fermented milk has a pleasant taste, without any particular bitterness or medicinal flavor, achieving good flavor acceptance while ensuring efficacy. It is a flavored fermented milk product perfectly suited for daily consumption to relieve fatigue. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0022] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0023] Currently, although there are reports of patents related to sports-oriented fermented milk products that incorporate plant-based ingredients, existing solutions often use a combination of multiple plant ingredients, resulting in complex formulations. Furthermore, plant extracts with anti-fatigue effects often have a distinctive bitter or medicinal taste, affecting the overall flavor of the fermented milk. Therefore, achieving good flavor acceptance while ensuring anti-fatigue efficacy remains a technical challenge for the industry. In addition, there is still room for improvement in the effectiveness of existing products in reducing blood lactate levels after exercise.

[0024] In view of this, the present invention provides a drinking-type flavored fermented milk and its preparation method. The drinking-type flavored fermented milk has a good taste and does not have any special bitterness or medicinal taste, making it more acceptable to the public. Furthermore, the fermented milk can quickly relieve post-exercise fatigue, reduce blood lactate concentration, and accelerate physical recovery after exercise. It is a flavored fermented milk product with fatigue-relieving effects that is very suitable for daily consumption.

[0025] Unless otherwise specified, the raw materials, reagents, and equipment used in the following examples and comparative examples of this invention are all commercially available products. In the following examples and comparative examples, *Streptococcus salivarius* subsp. *thermophilus* JMCC16, *Lactobacillus delbrueckii* subsp. *bulgaricus* JMCC0018, and *Lactococcus faecium* JMCC0035 were all prepared by adding freeze-dried bacterial powder to sterilized skim milk. *Lactobacillus plantarum* JMCC0017 used in Comparative Example 7 was isolated from traditional fermented dairy products in Xinjiang and has been disclosed in patent document CN107058159A. It is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCCNO.12323. The *Lactobacillus plantarum* used in Comparative Example 7 was prepared by adding its freeze-dried bacterial powder to sterilized skim milk.

[0026] Example 1 This embodiment provides a flavored fermented milk for drinking, the composition of which is shown in Table 1, and it is prepared according to the following method: Weigh each ingredient according to the composition formula in Table 1. After standardizing the raw milk, preheat it to 45°C. Under stirring conditions, add the weighed concentrated whey protein, white sugar, isomaltooligosaccharide, polygonatum extract and sea buckthorn concentrate to the raw milk in sequence. Stir continuously for 18 minutes until completely dissolved and dispersed to obtain the first emulsion.

[0027] The first emulsion was preheated to 60°C, then homogenized at a pressure of 17.5 MPa (secondary pressure 5 MPa, primary pressure 17.5 MPa), then sterilized at 95°C for 305 seconds, and cooled to 37°C to obtain the second emulsion.

[0028] The fermentation strains *Streptococcus salivarius* subsp. *thermophilus* JMCC16, *Lactobacillus delbrueckii* subsp. *bulgaricus* JMCC0018, and *Lactococcus faecium* JMCC0035 were inoculated into the second emulsion in a certain proportion and fermented at 37°C for 20 h. When the acidity was between 68 and 74°T and the pH was ≤ 4.58, the emulsion was broken and stirred for 10 min to obtain the third emulsion.

[0029] The third emulsion was homogenized a second time under a pressure of 7 MPa, cooled to 12°C and then filled. After refrigeration at 4°C for 18 hours, the finished product was obtained.

[0030] Example 2 This embodiment provides a flavored fermented milk for drinking, the composition of which is shown in Table 1, and it is prepared according to the following method: Weigh each ingredient according to the composition formula in Table 1. After standardizing the raw milk, preheat it to 40°C. Under stirring conditions, add the weighed concentrated whey protein, white sugar, isomaltooligosaccharide, polygonatum extract and sea buckthorn concentrate to the raw milk in sequence. Stir continuously for 20 minutes until completely dissolved and dispersed to obtain the first emulsion.

[0031] The first emulsion was preheated to 58°C, then homogenized at a pressure of 17.5 MPa (secondary pressure 5 MPa, primary pressure 17.5 MPa), and then sterilized at 93°C for 310 seconds. After cooling to 38°C, the second emulsion was obtained.

[0032] The fermentation strains *Streptococcus salivarius* subsp. *thermophilus* JMCC16, *Lactobacillus delbrueckii* subsp. *bulgaricus* JMCC0018, and *Lactococcus fatense* JMCC0035 were inoculated into the second emulsion in a certain proportion and fermented at 38°C for 18 hours. When the acidity was between 68 and 74°T and the pH was ≤ 4.58, the emulsion was broken and stirred for 8 minutes to obtain the third emulsion.

[0033] The third emulsion was homogenized a second time under a pressure of 8 MPa, cooled to 14°C and then filled. After refrigeration at 3°C ​​for 20 hours, the finished product was obtained.

[0034] Example 3 This embodiment provides a flavored fermented milk for drinking, the composition of which is shown in Table 1, and it is prepared according to the following method: Weigh each ingredient according to the composition formula in Table 1. After standardizing the raw milk, preheat it to 50°C. Under stirring conditions, add the weighed concentrated whey protein, white sugar, isomaltooligosaccharide, polygonatum extract and sea buckthorn concentrate to the raw milk in sequence. Stir continuously for 15 minutes until completely dissolved and dispersed to obtain the first emulsion.

[0035] The first emulsion was preheated to 62°C, then homogenized at a pressure of 17.5 MPa (secondary pressure 5 MPa, primary pressure 17.5 MPa), then sterilized at 98°C for 300 seconds, and cooled to 38°C to obtain the second emulsion.

[0036] The fermentation strains *Streptococcus salivarius* subsp. *thermophilus* JMCC16, *Lactobacillus delbrueckii* subsp. *bulgaricus* JMCC0018, and *Lactococcus faecium* JMCC0035 were inoculated into the second emulsion in a certain proportion and fermented at 38°C for 22 hours. When the acidity was between 68 and 74°T and the pH was ≤ 4.58, the emulsion was broken and stirred for 15 minutes to obtain the third emulsion.

[0037] The third emulsion was homogenized a second time under a pressure of 10 MPa, cooled to 10°C and then filled. After refrigeration at 6°C for 15 hours, the finished product was obtained.

[0038] Comparative Examples 1-7 Comparative Examples 1 to 7 of this invention each provide a drinking-type flavored fermented milk, the composition of which is shown in Table 1. The preparation method is the same as that in Example 1, and will not be repeated here.

[0039] Table 1 Test Example 1 The activity of the beverage-grade flavored fermented milk prepared in Examples 1-3 and Comparative Examples 1-7 was tested, and the testing steps are as follows: Pretreatment: Take 10 mL of each example and comparative sample, add 30 mL of 70% ethanol, extract by sonication for 30 min, centrifuge at 4000 rpm for 10 min, take the supernatant and make up to 50 mL for later use.

[0040] Determination of Polygonatum polysaccharide retention rate: The phenol-sulfuric acid method was used. Glucose was used as a standard, and the absorbance was measured at a wavelength of 490 nm to establish a standard curve. The content of Polygonatum polysaccharides in the sample was calculated. The theoretical content of Polygonatum polysaccharides at the time of feeding was calculated based on the amount of Polygonatum extract added and its polysaccharide content, and the theoretical polysaccharide content was 300 mg / 100 g.

[0041] Total flavonoid content determination: Spectrophotometric method was used. Rutin was used as a standard, and the absorbance was measured at a wavelength of 510 nm to establish a standard curve. The total flavonoid content in the sample was calculated, and the results were expressed as rutin equivalents (mg / 100g).

[0042] DPPH free radical scavenging rate determination: The DPPH method was used. 2 mL of sample solution was added to 2 mL of 0.2 mmol / L anhydrous DPPH ethanol solution. After mixing, the solution was reacted at room temperature in the dark for 30 min. The absorbance was measured at 517 nm. The absorbance of the DPPH working solution with an equal volume of distilled water was measured (A). 对照 ), Absorbance of DPPH working solution plus sample solution (A) 样品 ) and the absorbance (A) of the sample solution after adding an equal volume of anhydrous ethanol. 背景 The DPPH removal rate is calculated using the following formula: Statistical analysis: All data are expressed as mean ± standard deviation (mean ± SD), with three replicates per group. One-way ANOVA was performed using SPSSAU, with Example 1 serving as the control group. Post-hoc multiple comparisons were performed using the Dunnett method for the remaining examples and comparative examples. P <0.05 indicates a statistically significant difference, and the test results are shown in Table 2.

[0043] Table 2. Determination of antioxidant capacity in Examples 1-3 and Comparative Examples 1-7 Note: Each column in the table uses Example 1 as a control. express P <0.05, express P <0.01, ns indicates no significant difference ( P ≥ 0.05).

[0044] As shown in Table 2, the Polygonatum polysaccharide retention rate of Example 1 of this invention reached over 94%, and the total flavonoid content and DPPH scavenging rate were significantly better than those of the comparative examples. Examples 2-3 showed no significant differences from Example 1 in any of the three indicators. P (≥0.05), indicating that adjustments within the formulation and preparation process provided by this invention have no negative impact on the active ingredients and functions. Furthermore, it can be observed that the active ingredients of Polygonatum and Hippophae rhamnoides have a synergistic effect; the total flavonoid content when they are combined is higher than the total flavonoid content when either ingredient is combined with other plant materials. In addition, the combination of specific strain fermentation and plant extracts significantly affects the retention and conversion efficiency of active ingredients, demonstrating the advantages of the specific Lactococcus lactis strain selected in this invention.

[0045] The overall results demonstrate that this invention can effectively retain Polygonatum polysaccharides, promote the conversion of flavonoid aglycones, and achieve efficient utilization of active ingredients and a significant enhancement of antioxidant activity.

[0046] Test Example 2 Fatigue relief experiments were conducted on the beverage-type flavored fermented milk prepared in Example 1 and Comparative Example 1, respectively. The experimental design is as follows: 1. Preparation of experimental materials: Experimental group: Drinkable flavored fermented milk prepared in Example 1 (200mL / serving). Control group: Drinkable flavored fermented milk prepared in Comparative Example 1 (200 mL / serving). Control group: Placebo beverage (same appearance as the experimental group, ingredients include water, white sugar, isomaltooligosaccharide, without Polygonatum extract, sea buckthorn concentrate and fermentation strain, 200mL / serving) Instruments: Fitness tracker (capable of real-time heart rate measurement), stopwatch, Borg fatigue scale (RPE 6-20 points), Visual Analogue Scale (VAS 0-10 points), reaction time meter (or alternative video).

[0047] Experimental subjects: 30 healthy adult volunteers (aged 20-45, half male and half female, BMI 18.5-24.9 kg / m², exercising 2-5 times per week, excluding those with athletic talent, chronic diseases, and allergies to the experimental ingredients).

[0048] 2. Product drinking and exercise load test methods Grouping and Washout Period: Thirty subjects were randomly divided into three groups (A, B, and C), with 10 participants in each group. Each group underwent three rounds of testing with different beverages. The beverages consumed and the number of rounds are shown in Table 3. A 7-day washout period was set between each two rounds to ensure that no experimental components remained in the body. For data statistics and processing, the data from the three rounds of testing for the experimental group, control group, and blank group were combined for processing, with n=30.

[0049] Table 3. Experimental groupings and drinking methods for relieving fatigue Product consumption and exercise load: After each group (experimental group, control group and blank group) consumed the product (200mL / person), the subjects were allowed to stand for 30 minutes before a standardized step test was conducted to induce fatigue: the subjects continued to exercise at a fixed rhythm of "2 seconds up the step, 2 seconds down the step" until they could no longer maintain the rhythm (subjective exhaustion), and the duration of the exercise was recorded with a stopwatch; if obvious discomfort (such as dizziness or palpitations) occurred during the exercise, the exercise was stopped immediately and the time was recorded.

[0050] 3. Detection indicators Basic indicator measurement: On the day of the experiment, the subjects fasted for 4 hours and sat quietly for 10 minutes to measure the baseline heart rate (HR0) and fill in the baseline VAS fatigue score (the initial state was 0 points, with no feeling of fatigue).

[0051] Heart rate measurement: The heart rate of the subjects was measured immediately after exercise and 1 hour after exercise.

[0052] RPE score: Subjective fatigue perception was assessed using the Borg RPE scale (6-20 points) immediately after exercise and 1 hour after exercise. 6 points corresponded to "no effort" and 20 points corresponded to "exhaustion".

[0053] VAS Fatigue Score: Subjective fatigue was assessed using the VAS scale (0-10 points) immediately after exercise and 1 hour after exercise. 0 points represented "no fatigue" and 10 points represented "extreme fatigue".

[0054] Reaction time measurement: The reaction time (ms) of subjects to randomly occurring visual signals was measured immediately after exercise and 1 hour after exercise.

[0055] Blood lactate measurement: Blood was collected from the fingertips of the subjects immediately after exercise and 1 hour after exercise, and the whole blood lactate concentration was measured using a portable lactate analyzer.

[0056] The experimental results are shown in Table 4.

[0057] Table 4. Fatigue-relieving effect of Polygonatum and Seabuckthorn flavored fermented milk As shown in Table 4, compared with the blank group, the fermented flavored milk provided in Example 1 of this invention can significantly improve exercise endurance, accelerate heart rate recovery, reduce subjective fatigue, reduce post-exercise blood lactate levels, and maintain central nervous system function. Its effect is better than the control group (Comparative Example 1) without the addition of Polygonatum and Hippophae rhamnoides. Since the control group itself also has a certain fatigue-relieving effect, its effect is better than the blank group. However, the effect of the experimental group is particularly significant, indicating that the flavored fermented milk provided by this invention has a significant effect on relieving exercise fatigue and accelerating post-exercise recovery, and is very suitable for daily consumption by people who exercise a lot.

[0058] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A flavored fermented milk for drinking, characterized in that, The product comprises the following components by weight percentage: 82%–92% raw milk, 2%–5% concentrated whey protein, 2%–4% sweetener, 4%–6% isomaltooligosaccharide, 0.5%–1.5% Polygonatum extract, 0.3%–0.8% sea buckthorn concentrate, 0.005%–0.02% fermentation starter, and the balance being water. The fermentation strain is a complex of Streptococcus salivarius subsp. thermophilus JMCC16, Lactobacillus delbrueckii subsp. bulgaricus JMCC0018, and Lactococcus fatii JMCC0035.

2. The flavored fermented milk for drinking as described in claim 1, characterized in that, Among the fermentation strains, the viable count of Streptococcus salivarius subsp. thermophilus JMCC16 was 6.4 × 10⁻⁶. 9 CFU / mL ~1.7×10 10 The viable count of *Lactobacillus delbrueckii* subsp. bulgaricus JMCC0018 was 1.6 × 10⁻¹¹ CFU / mL. 8 CFU / mL ~8.6×10 8 CFU / mL, the viable count of *Lactococcus lactis* JMCC0035 was 8 × 10⁻⁶. 9 CFU / mL ~2×10 10 CFU / mL.

3. The flavored fermented milk for drinking as described in claim 2, characterized in that, The product comprises the following components by weight percentage: 85% raw milk, 3% concentrated whey protein, 3% sweetener, 5% isomaltooligosaccharide, 1.0% Polygonatum sibiricum extract, 0.5% sea buckthorn concentrate, 0.02% fermentation starter, and the remainder is water. The inoculation amounts of Streptococcus salivarius subsp. thermophilus JMCC16, Lactobacillus delbrueckii subsp. bulgaricus JMCC0018, and Lactococcus faecium JMCC0035 were 0.008%, 0.004%, and 0.008%, respectively.

4. The flavored fermented milk for drinking as described in claim 1, characterized in that, The content of Polygonatum polysaccharides in the Polygonatum extract is ≥30%, and the soluble solids in the sea buckthorn concentrate are ≥45%.

5. The method for preparing the beverage-grade flavored fermented milk according to any one of claims 1 to 4, characterized in that, Includes the following steps: Under stirring conditions, the concentrated whey protein, sweetener, isomaltooligosaccharide, polygonatum extract and sea buckthorn concentrate are added to the raw milk in sequence according to the formula ratio and stirred evenly to obtain the first emulsion. The first emulsion is preheated, then homogenized, sterilized and cooled to obtain the second emulsion; The fermentation strains were inoculated into the second emulsion in a certain proportion, and fermentation and demulsification were carried out in sequence to obtain the third emulsion. The third emulsion is homogenized a second time, cooled again, and then sequentially filled and refrigerated for ripening to obtain the beverage-grade flavored fermented milk.

6. The method for preparing a beverage-grade flavored fermented milk as described in claim 5, characterized in that, In preparing the first emulsion, the raw milk is preheated to 40-50°C.

7. The method for preparing a beverage-grade flavored fermented milk as described in claim 5, characterized in that, The first emulsion is preheated, then homogenized, sterilized and cooled, specifically as follows: the first emulsion is preheated to 58~62℃, homogenized at 17~18MPa pressure, sterilized at 93~98℃ for 300~310s, and then cooled to 36~38℃.

8. The method for preparing a beverage-grade flavored fermented milk as described in claim 5, characterized in that, The fermentation conditions are: fermentation at 36~38℃ for 18~22 hours.

9. The method for preparing a beverage-grade flavored fermented milk as described in claim 5, characterized in that, After the second emulsion ferments, when the acidity reaches 68-74°T and the pH ≤ 4.58, demulsification begins 5-15 minutes later.

10. The method for preparing a beverage-grade flavored fermented milk as described in claim 5, characterized in that, The pressure for the second homogenization is 5~10MPa; The filling temperature is 10~15℃; The specific process of cold-curing is as follows: ripening at 2~6℃ for 12~24 hours.

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