A fermented ginseng yogurt and its preparation method

Abstract

This invention relates to the field of dairy processing technology, specifically disclosing a fermented ginseng yogurt and its preparation method. The fermented ginseng yogurt is made from raw milk, a yam-ginseng matrix solution, a biological carrier, fruit and vegetable powder, sugar substitute, and a compound fermentation agent. This invention uses enzymatic hydrolysis and Maillard reaction to prepare the matrix solution for deodorization; ginseng extract is loaded onto a modified Poria cocos microparticle framework, and a polyelectrolyte composite membrane is constructed through calcium ion cross-linking and chitosan electrostatic assembly to improve system stability and regulate the release of active ingredients; fermented fruit and vegetable powder is used to synergistically harmonize the flavor; and a variable-temperature fermentation process is combined to promote the conversion of ginsenosides. The resulting yogurt has a delicate texture, low whey separation rate, harmonious flavor, and good sensory quality and functional component conversion effect.

Description

Technical Field

[0001] This invention relates to the field of dairy processing technology, and more specifically, to a fermented ginseng yogurt and its preparation method. Background Technology

[0002] Ginseng, known as the "King of Herbs," possesses a variety of pharmacological activities, including enhancing immunity, combating fatigue, and slowing aging, thanks to its core active ingredient, ginseng extract. With the increasing popularity of the concept of food and medicine sharing the same origin, the application of ginseng in everyday dairy products such as yogurt has become a hot topic in functional food development.

[0003] However, existing technologies face three major technical bottlenecks that are difficult to overcome in developing ginseng yogurt: 1. Poor taste and flavor, with bitterness difficult to mask: Natural ginseng contains special volatile components, mainly methoxypyrazine compounds (such as 2-isopropyl-3-methoxypyrazine) and sesquiterpenes (such as β-ginsenosides), which result in an unacceptable earthy and astringent taste in ginseng products, as well as a strong bitterness from some ginseng extracts. Current technologies mostly use physical mixing methods, that is, adding ginseng powder or crude extract directly before or after yogurt fermentation. This simple addition not only fails to mask the off-flavor of ginseng but also destroys the original pure milky aroma of yogurt, leading to low sensory acceptance of the product. Although some products attempt to mask this by adding large amounts of sucrose or flavorings, this goes against the healthy, low-sugar consumption trend.

[0004] 2. Poor system stability, prone to precipitation and whey separation: Ginseng and medicinal and edible excipients (such as yam) contain a large amount of plant fiber and starch, which can easily disrupt the gel network structure of casein micelles when directly added to the milk system. Especially in acidic environments, plant particles are prone to flocculation and sedimentation, resulting in obvious stratification, a rough texture, and severe whey separation in the yogurt.

[0005] 3. Low bioavailability of active ingredients: The main active ingredients in ginseng are large-molecule ginseng extracts (such as Rb1 and Rg1), which are highly polar and difficult to be directly absorbed by the human intestine. Studies have shown that only by converting them into small-molecule rare ginseng extracts (such as Compound K and Rg3) can the best efficacy be achieved. However, conventional yogurt fermentation processes typically use constant-temperature fermentation, which is mainly conducive to the production of acid curds by Streptococcus thermophilus, but is not the optimal condition for the biotransformation of active ingredients by lactic acid bacteria secreting β-glucosidase, resulting in a low conversion rate of active ingredients in the product.

[0006] Therefore, there is an urgent need to develop a fermented ginseng yogurt preparation technology that can effectively remove the bitter and fishy smell of ginseng, maintain the uniformity and stability of the system, and improve the bioavailability of ginseng extract.

[0007] Based on the above statements, this invention proposes a fermented ginseng yogurt and its preparation method. Summary of the Invention

[0008] To address the problems of bitterness, low bioavailability, and uneven texture in existing ginseng yogurt, this invention provides a fermented ginseng yogurt and its preparation method.

[0009] In a first aspect, the present invention provides a fermented ginseng yogurt, employing the following technical solution: A fermented ginseng yogurt comprises the following ingredients in parts by weight: 80-90 parts raw milk, 15-25 parts yam-ginseng matrix liquid, 3-5 parts biological carrier, 5-8 parts fruit and vegetable powder, 4-5 parts sugar substitute, and 0.05-0.08 parts compound fermentation agent.

[0010] Preferably, the sugar substitute is composed of stachyose and trehalose in a mass ratio of 1:2-3.

[0011] Preferably, the compound fermentation agent is composed of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum and Bifidobacterium longum in an effective viable count ratio of 1.5-2.5:1-1.5:1.5-2.5:1.

[0012] Preferably, the preparation method of the yam-ginseng matrix solution includes the following steps: A1. After mixing dried ginseng, dried Chinese yam and soy protein isolate, place them in an air jet mill for ultra-fine grinding. The particle size D90 < 15 μm is pulverized to obtain mixed medicinal powder. A2. Mix the mixed medicinal powder and distilled water, gelatinize at high temperature, cool to 50-55℃, add neutral protease and flavor protease, stir to react, and after the reaction is completed, obtain the enzymatic hydrolysate. A3. Add glucose to the enzymatic hydrolysate, adjust the pH of the system to 6.5-7.5, stir the reaction, and after the reaction is completed, perform high-pressure homogenization to obtain yam-ginseng matrix solution.

[0013] By adopting the above technical solution, hydrophobic short peptides produced by the enzymatic hydrolysis of soybean isolates coexist with polysaccharides and saponins in ginseng and yam. Under high temperature and in the presence of reducing sugars, Maillard reaction occurs to form flavor substances with nutty aroma, thereby reducing the original earthy and bitter taste of ginseng. At the same time, the small nitrogen-containing substances formed after the protein is enzymatically hydrolyzed can serve as a usable nitrogen source for fermentation bacteria, which helps to shorten the fermentation start-up stage and improve fermentation efficiency.

[0014] Preferably, the mass ratio of dried ginseng, dried Chinese yam, and soy protein isolate in step A1 is 1-2:2-3:4-6.

[0015] Preferably, the ultrafine pulverization in step A1 refers to pulverizing for 10-15 minutes under the conditions of a pressure of 0.6-0.8 MPa and a classifying wheel speed of 3000-4000 rpm.

[0016] Preferably, in step A2, the mass ratio of the mixed medicinal powder, distilled water, neutral protease and flavor protease is 100:800-900:0.5-1.0:0.4-0.5.

[0017] Preferably, the high-temperature gelatinization in step A2 refers to holding at a temperature of 90-95℃ for 15-20 minutes.

[0018] Preferably, the stirring reaction in step A2 refers to stirring the reaction at a speed of 100-200 rpm for 2-3 hours.

[0019] Preferably, the mass ratio of glucose to enzymatic hydrolysate in step A3 is 2-4:100.

[0020] Preferably, the stirring reaction in step A3 refers to stirring the reaction for 20-30 minutes at a temperature of 95-105℃ and a rotation speed of 100-200 rpm.

[0021] Preferably, in step A3, high-pressure homogenization refers to cyclic homogenization 2-3 times under a pressure of 20-25 MPa.

[0022] Preferably, the method for preparing the biological carrier includes the following steps: B1. Disperse Poria cocos powder in distilled water, adjust the pH of the system to 5.0-6.0, add cellulase and β-glucanase to carry out enzymatic hydrolysis reaction. After the reaction is completed, perform enzyme inactivation treatment, centrifuge, wash, dry, pulverize and sieve to obtain modified Poria cocos microparticles. B2. Dissolve ginseng extract in sodium alginate aqueous solution, add modified Poria cocos microparticles, stir evenly to form a mixed slurry; B3. While stirring, add the mixed slurry to the calcium lactate aqueous solution, continue stirring until uniform, let stand and solidify for 20-30 minutes, filter and wash to obtain wet granules; B4. Add chitosan to an aqueous acetic acid solution and stir until completely dissolved. Adjust the pH of the system to 4.5-5.0 to obtain a chitosan-acetic acid solution. Immerse the wet particles in the chitosan-acetic acid solution and continue stirring until homogeneous. After filtration, washing, and drying, obtain the biological carrier.

[0023] By adopting the above technical solution, the porous structure of the modified Poria cocos microparticles is conducive to loading ginseng extract; sodium alginate crosslinks with calcium ions to form a gel, and further forms a polyelectrolyte composite membrane layer on its surface through electrostatic assembly of chitosan, thereby inhibiting the release of bitter substances under acidic conditions and improving product palatability and system stability; under neutral conditions, the composite structure is more likely to dissociate, making the loaded components easier to release, which is conducive to improving the utilization efficiency of active ingredients.

[0024] Preferably, in step B1, the mass ratio of Poria cocos powder, cellulase, β-glucanase and distilled water is 100:0.5-1:0.5-1:800-1000.

[0025] Preferably, the enzymatic hydrolysis reaction in step B1 refers to the enzymatic hydrolysis reaction for 1.5-2.5 hours under the conditions of 55-60℃ and 150-250rpm.

[0026] Preferably, the enzyme inactivation treatment in step B1 refers to: heating to 90-100℃ to inactivate the enzyme for 10-15 minutes.

[0027] Preferably, in step B1, centrifugation, washing, and drying refer to: centrifuging at 4000-5000 rpm for 10-15 min, washing the solid with distilled water 2-3 times, and then placing it in a vacuum drying oven and drying it to constant weight under vacuum conditions of -0.08 MPa to -0.095 MPa and temperature of 50-55℃.

[0028] Preferably, in step B1, pulverizing and sieving refers to: using an air jet mill to pulverize the dried solid and passing it through a 600-800 mesh sieve.

[0029] Preferably, the particle size of the modified Poria cocos microparticles in step B1 is 10-20 μm.

[0030] Preferably, in step B2, the mass ratio of ginseng extract, modified Poria cocos microparticles, and sodium alginate aqueous solution is 1:3-5:15-25.

[0031] Preferably, the mass fraction of sodium alginate aqueous solution in step B2 is 1.5-2.0%.

[0032] Preferably, the term "stirring evenly" in step B2 refers to stirring for 30-40 minutes at room temperature and a speed of 300-500 rpm.

[0033] Preferably, the mass ratio of the mixed slurry to the calcium lactate aqueous solution in step B3 is 1:5-10.

[0034] Preferably, the mass fraction of the calcium lactate aqueous solution in step B3 is 2.0-3.0%.

[0035] Preferably, in step B3, the stirring speed is 80-100 rpm, and the stirring time is 20-30 min.

[0036] Preferably, in step B3, the filtration and washing process refers to: using a 200-250 mesh filter for filtration, and washing the solid with distilled water 2-3 times.

[0037] Preferably, in step B4, the mass ratio of chitosan, aqueous acetic acid solution, and wet particles is 1-1.5:100:25-35.

[0038] Preferably, the mass fraction of the acetic acid aqueous solution in step B4 is 1.0-2.0%.

[0039] Preferably, the stirring in step B4 refers to stirring at room temperature and a speed of 200-400 rpm for 2-4 hours, followed by stirring for 10-15 minutes.

[0040] Preferably, in step B4, the filtration, washing, and drying process refers to: filtering with a 100-200 mesh filter, washing the solid with distilled water until the washing liquid is neutral, and then placing it in a vacuum freeze dryer and freeze-drying it at a temperature of -40°C to -50°C for 36-48 hours.

[0041] Preferably, the method for preparing the fruit and vegetable powder includes the following steps: C1. Mix washed and chopped carrots, fresh berries and distilled water and blend to obtain fruit and vegetable pulp. Add pectinase and cellulase to the fruit and vegetable pulp, adjust the pH of the system to 4.5-5.5, and carry out enzymatic hydrolysis. After the enzymatic hydrolysis is completed, the enzymatically hydrolyzed pulp is obtained. C2. Add the mixed bacterial culture to the enzymatic hydrolysate for anaerobic fermentation. After fermentation, dry, pulverize and sieve to obtain fruit and vegetable powder.

[0042] By adopting the above technical solutions, compound enzyme treatment is beneficial for cell wall breaking and improving the release of pigments and nutrients; the organic acid environment formed by fermentation can, to a certain extent, inhibit the deterioration of pigments during processing, thereby improving the color of the finished product; at the same time, mixed bacteria fermentation can reduce the earthy and astringent taste in the raw materials and produce flavor metabolites, which, together with the milky aroma, improve the overall flavor and palatability of yogurt.

[0043] Preferably, the fresh berries in step C1 are selected from one or more of blueberries, mulberries, raspberries, and cranberries.

[0044] Preferably, in step C1, the mass ratio of fresh berries, carrots, distilled water, pectinase, and cellulase is 50-60:40-50:100-120:0.1-0.2:0.1-0.2.

[0045] Preferably, in step C1, pulping refers to: using a high-speed tissue homogenizer, pulping at a speed of 6000-7000 rpm for 3-5 minutes, and then passing it through a 50-70 mesh sieve.

[0046] Preferably, the enzymatic hydrolysis reaction in step C1 refers to enzymatic hydrolysis for 1.5-2 hours at 45-50℃ and 60-100 rpm.

[0047] Preferably, the mass ratio of the mixed bacterial strain to the enzymatic hydrolysate in step C2 is 2-4:100.

[0048] Preferably, the mixed bacterial strains in step C2 are Lactobacillus plantarum and Leuconostoc mesenteroides in a mass ratio of 1:1-1.2.

[0049] Preferably, in step C2, anaerobic fermentation refers to fermentation at 30-35℃ under sealed conditions for 24-36 hours.

[0050] Preferably, in step C2, drying, pulverizing, and sieving refers to: freeze-drying for 36-48 hours until the moisture content is <5% under conditions of cold trap temperature of -45℃ to -50℃ and vacuum degree <100Pa, and under conditions of relative humidity <40%, using an ultra-micro pulverizer with a circulating water-cooled jacket, setting the pulverizer speed to 8000-12000rpm, controlling the temperature inside the pulverizing chamber to ≤30℃ for pulverization, and passing it through a 100-120 mesh sieve.

[0051] Secondly, the present invention provides a method for preparing fermented ginseng yogurt, which adopts the following technical solution: A method for preparing fermented ginseng yogurt includes the following preparation steps: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.0%-3.5% and a protein content of 2.8%-3.2%. S2. Weigh out the raw milk, yam-ginseng matrix liquid, biological carrier, fruit and vegetable powder, sugar substitute and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 55-60℃, add the yam-ginseng base liquid and sugar substitute, stir well to obtain the mixed liquid; S4. Heat the mixture to 60-65℃, homogenize under high pressure, pasteurize, and then cool to 40-42℃ for later use. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and biological carrier to the cooled liquid, stir evenly, and then carry out variable temperature fermentation. After fermentation, cool to 15-20℃, fill into bottles and let stand at 4-6℃ for 18-24 hours to ripen, and obtain fermented ginseng yogurt.

[0052] Preferably, the term "stirring evenly" in step S3 refers to stirring at a speed of 1000-1200 rpm for 10-15 minutes.

[0053] Preferably, in step S4, high-pressure homogenization refers to high-pressure homogenization performed under the conditions of a first-stage homogenization pressure of 18-22 MPa and a second-stage homogenization pressure of 3-5 MPa.

[0054] Preferably, in step S4, pasteurization refers to pasteurization at 90-95°C for 5-10 minutes.

[0055] Preferably, the term "stirring evenly" in step S5 refers to stirring at a speed of 30-50 rpm for 5-10 minutes.

[0056] Preferably, the variable temperature fermentation in step S5 refers to: first fermenting at a temperature of 40-42℃ for 2.5-3.0 hours, and then continuing fermentation at a temperature of 35-37℃ until the lactic acidity reaches 75-80°T.

[0057] By adopting the above technical solutions, the two-stage high-pressure homogenization process promotes the formation of a protein-polysaccharide coating layer on the surface of the biological carrier by whey protein and casein, thereby reducing particle sedimentation and whey precipitation; the variable temperature fermentation can regulate acid production and microbial metabolism in stages, while ensuring gel formation and promoting the conversion of some ginsenosides into rarer saponin forms that are more easily absorbed, thereby improving the level of functional components in the product.

[0058] In summary, the present invention has the following beneficial effects: 1. This invention utilizes a yam-ginseng matrix solution to effectively mask the inherent unpleasant flavor of ginseng through a directional Maillard reaction. Ginseng, yam, and soy protein isolate are co-treated; the enzymatic hydrolysis produces hydrophobic short peptides that react with polysaccharides and saponins in the presence of glucose at high temperature to generate pyrazine compounds with a nutty aroma, thereby neutralizing the earthy and bitter taste of ginseng. Simultaneously, this process converts large protein molecules into small nitrogen sources, effectively shortening the lag period of yogurt fermentation and improving production efficiency.

[0059] 2. This invention uses enzymatically modified porous Poria cocos microparticles as a framework to adsorb ginseng extract. A polyelectrolyte composite membrane layer is constructed through calcium ion crosslinking and chitosan electrostatic assembly to form a biological carrier. This biological carrier maintains a dense structure in the acidic environment of yogurt and stomach, preventing bitter substances from escaping. After reaching the neutral environment of the intestine, it quickly dissolves and releases active ingredients, thereby improving the palatability of the product and increasing its bioavailability.

[0060] 3. The present invention adopts a process of combined enzymatic hydrolysis and symbiotic fermentation of Lactobacillus plantarum and Leuconostoc mesenteroides. On the one hand, it improves the dissolution and stability of anthocyanins in berries and β-carotene in carrots, endows the product with natural color, and solves the problem of dull color in traditional ginseng products. On the other hand, microorganisms metabolize and transform the earthy smell and astringent substances in the raw materials and produce flavor metabolites, further masking the possible residual bitterness and significantly enhancing the overall flavor and palatability of the yogurt.

[0061] 4. By optimizing the overall formula and fermentation process, the present invention integrates the nutritional components and functions of various natural ingredients such as ginseng, Chinese yam, Poria cocos, fruits and vegetables, etc. Through the action of a compound starter and a variable-temperature fermentation process, it ensures that the product has a delicate texture, a mild sour taste, and a high viable count of bacteria. The finally prepared finished product solves the sensory problems of using ginseng in food, and is a fermented dairy product with good flavor, color, taste and probiotic functions. Detailed implementation manners

[0062] The following further elaborates on the present invention in combination with examples.

[0063] For those not specifying specific experimental steps or conditions in the examples, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For reagents or instruments not indicating the manufacturer, they are all conventional reagent products that can be obtained through commercial purchase.

[0064] The sources of the key raw materials used in the present invention are as follows: Dried ginseng: provided by Jilin Shenle Biotechnology Co., Ltd. Dried Chinese yam: brand: Yihegu, provided by Shandong Hegu Food Co., Ltd. Soybean protein isolate: brand: Qinuo, provided by Henan Runde Food Ingredients Co., Ltd. Neutral protease: brand: Yujian Hongyi, product grade: food grade, enzyme activity: 100,000 U / g, provided by Guangzhou Hongyi Food Additives Co., Ltd. Flavor protease: brand: Pangbo Biology, product grade: food grade, enzyme activity: 20,000 U / g, provided by Nanning Pangbo Bioengineering Co., Ltd. Glucose: brand: Fufeng, product grade: food grade, provided by Jinan Maoxin Chemical Co., Ltd. Poria cocos powder: brand: Ruiqi, provided by Xinghua Ruiqi Food Co., Ltd. β-glucanase: brand: SUNSON / Xiasheng, enzyme activity: 5000 U / g, provided by Ningxia Xiasheng Industrial Group Co., Ltd. Ginseng extract: brand: Juntao, product number: JTSWRSZG80, provided by Xi'an Juntao Biotechnology Co., Ltd. Sodium alginate: Brand: Mingyue, Product grade: Food grade, provided by Henan Guangheng Food Ingredients Co., Ltd.; Calcium lactate: Brand: Jindan, Product grade: Food grade, provided by Henan Anrui Biotechnology Co., Ltd.; Pectinase: Brand: SUNSON / Xiasheng, Enzyme activity: 60,000 U / g, provided by Ningxia Xiasheng Industrial Group Co., Ltd.; Cellulase: Brand: SUNSON / Xiasheng, Enzyme activity: 10,000 U / g, Article number: FFY-0673, provided by Ningxia Xiasheng Industrial Group Co., Ltd.; Lactobacillus plantarum: Brand: Shouhe, Content of active substances: 100 billion CFU / g, provided by Xi'an Shouhe Biotechnology Co., Ltd.; Leuconostoc mesenteroides: Number of viable bacteria: 1.24×10 11 CFU / g, Product grade: Food grade, provided by Zhejiang Yicun Biotechnology Co., Ltd.; Stachyose: CAS number: 10094-58-3, Product grade: Food grade, provided by Zhejiang Yicun Biotechnology Co., Ltd.; Trehalose: CAS number: 99-20-7, Product grade: Food grade, provided by Shanghai Quanyan Biotechnology Co., Ltd.; Streptococcus thermophilus: Brand: ZhengHui Bio, Content of active substances: 10 billion CFU / g, provided by Shaanxi ZhengHui Biotechnology Co., Ltd.; Lactobacillus bulgaricus: Brand: ZhengHui Bio, Content of active substances: 10 billion CFU / g, provided by Xi'an Shouhe Biotechnology Co., Ltd.; Lactobacillus plantarum: Brand: ZhengHui Bio, Content of active substances: 10 billion CFU / g, provided by Xi'an Shouhe Biotechnology Co., Ltd.; Bifidobacterium longum: Brand: TH, Content of active substances: 10 billion CFU / g, provided by Xi'an Tianhe Pharmaceutical Co., Ltd.

[0065] Examples 1-3 provide a fermented ginseng yogurt and its preparation method.

[0066] Example 1 The preparation method of the yam-ginseng matrix solution includes the following steps: A1. Control the mass ratio of dried ginseng, dried Chinese yam, and soy protein isolate to be 1:2:4. After mixing dried ginseng, dried Chinese yam, and soy protein isolate, place them in a jet mill and grind for 15 min under the conditions of a pressure of 0.6 MPa and a classifier wheel speed of 3000 rpm. The grinding particle size D90 < 15 μm to obtain a mixed medicinal powder; A2. Control the mass ratio of mixed medicinal powder, distilled water, neutral protease and flavor protease to 100:800:0.5:0.4. Mix the mixed medicinal powder and distilled water, keep it at 90℃ for 20 minutes for high-temperature gelatinization, cool it down to 50℃, add neutral protease and flavor protease, stir at 100 rpm for 3 hours. After the reaction is completed, the enzymatic hydrolysate is obtained. A3. Control the mass ratio of glucose to enzymatic hydrolysate to 2:100. Add glucose to the enzymatic hydrolysate and adjust the pH of the system to 6.5 using a 10wt% sodium bicarbonate aqueous solution. Stir the reaction at 95℃ and 100rpm for 30min. After the reaction is completed, homogenize twice under a pressure of 20MPa to obtain yam-ginseng matrix solution. Cool to 0℃ for later use. The preparation method of the biological carrier includes the following steps: B1. The mass ratio of Poria cocos powder, cellulase, β-glucanase and distilled water was controlled at 100:0.5:0.5:800. The Poria cocos powder was dispersed in distilled water, and the pH of the system was adjusted to 5.0 using 10wt% citric acid aqueous solution. Cellulase and β-glucanase were added, and the enzymatic hydrolysis reaction was carried out at 55℃ and 150rpm for 2.5h. After the reaction was completed, the temperature was raised to 90℃ to inactivate the enzyme for 15min, and centrifuged at 4000rpm for 15min. The solid was washed twice with distilled water and placed in a vacuum drying oven. It was dried to constant weight under vacuum of -0.08MPa and temperature of 50℃. The dried solid was pulverized using an air jet mill and passed through a 600-mesh sieve to obtain modified Poria cocos microparticles with a particle size of 10μm. B2. Control the mass ratio of ginseng extract, modified Poria cocos microparticles and sodium alginate aqueous solution to 1:3:15. Dissolve ginseng extract in sodium alginate aqueous solution with a mass fraction of 1.5%, add modified Poria cocos microparticles, and stir for 40 minutes at room temperature and 300 rpm to form a mixed slurry. B3. Control the mass ratio of the mixed slurry and the calcium lactate aqueous solution to 1:5. At room temperature and 80 rpm, add the mixed slurry to a 2.0% calcium lactate aqueous solution and continue stirring for 30 min. Let it stand and solidify for 30 min. Filter it using a 200-mesh filter. Wash the solid twice with distilled water to obtain wet granules. B4. Control the mass ratio of chitosan, acetic acid aqueous solution and wet particles to 1:100:25. Add chitosan to acetic acid aqueous solution and stir for 4 hours at room temperature and 200 rpm until completely dissolved. Adjust the pH of the system to 4.5 using 1 wt% sodium hydroxide solution to obtain chitosan acetic acid solution. Immerse the wet particles in chitosan acetic acid solution and continue stirring for 15 min. Filter using a 100-mesh filter. Wash the solid with distilled water until the washing liquid is neutral. Place it in a vacuum freeze dryer and freeze dry at -40℃ for 48 h to obtain the biological carrier. The preparation method of fruit and vegetable powder includes the following steps: C1. Control the mass ratio of blueberries, carrots, distilled water, pectinase, and cellulase to 50:40:100:0.1:0.1. Mix the washed and chopped carrots, blueberries, and distilled water, and then use a high-speed tissue homogenizer to homogenize at 6000 rpm for 5 minutes. Pass the mixture through a 50-mesh sieve to obtain fruit and vegetable pulp. Add pectinase and cellulase to the fruit and vegetable pulp, and adjust the pH of the system to 4.5 using a 10wt% citric acid aqueous solution. Enzymatically hydrolyze the mixture at 45℃ and 60 rpm for 2 hours. After enzymatic hydrolysis, obtain the enzymatically hydrolyzed pulp. C2. Control the mass ratio of mixed bacterial strains and enzymatic hydrolysate to 2:100. Add the mixed bacterial strains (Lactobacillus plantarum and Leuconostoc mesenteroides in a mass ratio of 1:1) to the enzymatic hydrolysate and ferment at 30℃ in a sealed environment for 36 hours. After fermentation, freeze-dry the mixture at a cold trap temperature of -45℃ and a vacuum degree of <100Pa for 48 hours until the moisture content is <5%. Under the condition of relative humidity of <40%, use an ultra-micro pulverizer with a circulating water-cooled jacket, set the pulverizer speed to 8000rpm, control the temperature inside the pulverizing chamber to 30℃ for pulverization, and pass it through a 100-mesh sieve to obtain fruit and vegetable powder. The artificial sweetener is composed of stachyose and trehalose in a mass ratio of 1:2; The compound fermentation agent is composed of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum and Bifidobacterium longum mixed in an effective live bacteria ratio of 1.5:1:1.5:1; A fermented ginseng yogurt comprises the following ingredients in parts by weight: 80 parts raw milk, 15 parts yam-ginseng matrix liquid, 3 parts biological carrier, 5 parts fruit and vegetable powder, 4 parts sugar substitute, and 0.05 parts compound fermentation agent; A method for preparing fermented ginseng yogurt includes the following preparation steps: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.0% and a protein content of 2.8%. S2. Weigh out the raw milk, yam-ginseng matrix liquid, biological carrier, fruit and vegetable powder, sugar substitute and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 55°C, add the yam-ginseng matrix liquid and sugar substitute, and stir at 1000 rpm for 15 minutes to obtain the mixed liquid. S4. Heat the mixture to 60°C, perform high-pressure homogenization under the conditions of primary homogenization pressure of 18MPa and secondary homogenization pressure of 3MPa, raise the temperature to 90°C, pasteurize for 10 minutes, and then cool to 40°C for later use. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and biological carrier to the cooled liquid. Stir at 30 rpm for 10 min and place in a fermentation tank. Ferment at 40℃ for 3.0 h, and then continue fermentation at 35℃ until the lactic acidity reaches 75°T. After fermentation, cool to 15℃ through a tubular heat exchanger. After filling, let stand at 4℃ for 24 h to ripen and obtain fermented ginseng yogurt.

[0067] Example 2 The preparation method of yam-ginseng matrix solution includes the following steps: A1. Control the mass ratio of dried ginseng, dried Chinese yam and soy protein isolate to 1.5:2.5:5. Mix the dried ginseng, dried Chinese yam and soy protein isolate and place them in an air jet mill. Grind them for 12.5 min under the conditions of 0.7 MPa pressure and 3500 rpm classifier speed. The particle size D90 is <15 μm to obtain mixed medicinal powder. A2. Control the mass ratio of mixed medicinal powder, distilled water, neutral protease and flavor protease to 100:850:0.75:0.45. Mix the mixed medicinal powder and distilled water, keep it at 93℃ for 17.5 min for high-temperature gelatinization, cool it down to 53℃, add neutral protease and flavor protease, stir at 150 rpm for 2.5 h, and after the reaction is completed, obtain the enzymatic hydrolysate. A3. Control the mass ratio of glucose to enzymatic hydrolysate to 3:100. Add glucose to the enzymatic hydrolysate and adjust the pH of the system to 7 using 10wt% sodium bicarbonate aqueous solution. Stir the reaction at 100℃ and 150rpm for 25min. After the reaction is completed, homogenize the solution three times under a pressure of 22MPa to obtain yam-ginseng matrix solution. Cool it to 2℃ for later use. The preparation method of the biological carrier includes the following steps: B1. The mass ratio of Poria cocos powder, cellulase, β-glucanase and distilled water was controlled at 100:0.75:0.75:900. The Poria cocos powder was dispersed in distilled water, and the pH of the system was adjusted to 5.5 using 10wt% citric acid aqueous solution. Cellulase and β-glucanase were added, and the enzymatic hydrolysis reaction was carried out at 58℃ and 200rpm for 2h. After the reaction was completed, the temperature was raised to 95℃ to inactivate the enzyme for 12.5min, and centrifuged at 4500rpm for 12.5min. The solid was washed three times with distilled water and placed in a vacuum drying oven. It was dried to constant weight under a vacuum of -0.09MPa and a temperature of 53℃. The dried solid was pulverized using an air jet mill and passed through a 700-mesh sieve to obtain modified Poria cocos microparticles with a particle size of 15μm. B2. Control the mass ratio of ginseng extract, modified Poria cocos microparticles and sodium alginate aqueous solution to 1:4:20. Dissolve ginseng extract in sodium alginate aqueous solution with a mass fraction of 2.0%, add modified Poria cocos microparticles, and stir for 35 minutes at room temperature and 400 rpm to form a mixed slurry. B3. Control the mass ratio of the mixed slurry and the calcium lactate aqueous solution to 1:7.5. At room temperature and 90 rpm, add the mixed slurry to a 2.5% calcium lactate aqueous solution and continue stirring for 25 min. Let it stand and solidify for 25 min. Filter using a 230-mesh filter. Wash the solid three times with distilled water to obtain wet granules. B4. Control the mass ratio of chitosan, acetic acid aqueous solution, and wet particles to 1.25:100:30. Add chitosan to the acetic acid aqueous solution and stir for 3 hours at room temperature and 300 rpm until completely dissolved. Adjust the pH of the system to 4.5 using 1 wt% sodium hydroxide solution to obtain chitosan acetic acid solution. Immerse the wet particles in the chitosan acetic acid solution and continue stirring for 12.5 min. Filter using a 150-mesh filter. Wash the solid with distilled water until the washing liquid is neutral. Place it in a vacuum freeze dryer and freeze dry at -45℃ for 42 hours to obtain the biological carrier. The preparation method of fruit and vegetable powder includes the following steps: C1. The mass ratio of mulberry, carrot, distilled water, pectinase, and cellulase was controlled at 55:45:110:0.15:0.15. The washed and chopped carrots, mulberries, and distilled water were mixed and then homogenized using a high-speed tissue homogenizer at 6500 rpm for 4 minutes. The mixture was then passed through a 60-mesh sieve to obtain fruit and vegetable pulp. Pectinase and cellulase were added to the fruit and vegetable pulp, and the pH of the system was adjusted to 5 using a 10wt% citric acid aqueous solution. The mixture was then enzymatically hydrolyzed at 48℃ and 80 rpm for 1.75 hours. After the enzymatic hydrolysis was completed, the enzymatically hydrolyzed pulp was obtained. C2. Control the mass ratio of mixed bacterial strains and enzymatic hydrolysate to 3:100. Add the mixed bacterial strains (the mass ratio of Lactobacillus plantarum and Leuconostoc mesenteroides is 1:1.1) to the enzymatic hydrolysate and ferment at 32℃ in a sealed environment for 30 hours. After fermentation, freeze-dry the mixture at a cold trap temperature of -48℃ and a vacuum degree of <100Pa for 42 hours until the moisture content is <5%. Under the condition of relative humidity of <40%, use an ultra-micro pulverizer with a circulating water-cooled jacket, set the pulverizer speed to 10000rpm, control the temperature inside the pulverizing chamber to 28℃ for pulverization, and pass it through a 110-mesh sieve to obtain fruit and vegetable powder. The artificial sweetener is composed of stachyose and trehalose in a mass ratio of 1:2.5; The compound fermentation agent is composed of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum and Bifidobacterium longum mixed in an effective live bacteria ratio of 2:1.2:2:1; A fermented ginseng yogurt comprises the following ingredients in parts by weight: 85 parts raw milk, 20 parts yam-ginseng matrix liquid, 4 parts biological carrier, 6.5 parts fruit and vegetable powder, 4.5 parts sugar substitute, and 0.07 parts compound fermentation agent; A method for preparing fermented ginseng yogurt includes the following preparation steps: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.3% and a protein content of 3.0%. S2. Weigh out the raw milk, yam-ginseng matrix liquid, biological carrier, fruit and vegetable powder, sugar substitute and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 58°C, add the yam-ginseng matrix liquid and sugar substitute, and stir at 1100 rpm for 12.5 min to obtain the mixed liquid; S4. Heat the mixture to 63°C, perform high-pressure homogenization under the conditions of primary homogenization pressure of 20MPa and secondary homogenization pressure of 4MPa, raise the temperature to 93°C, pasteurize for 7.5 minutes, and then cool to 41°C for later use. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and biological carrier to the cooled liquid. Stir at 40 rpm for 7.5 min and place in a fermentation tank. First, ferment at 41℃ for 2.8 h, and then continue fermentation at 36℃ until the lactic acidity reaches 77°T. After fermentation, cool to 18℃ through a tubular heat exchanger. After filling, let stand at 5℃ for 21 h to ripen and obtain fermented ginseng yogurt.

[0068] Example 3 The preparation method of yam-ginseng matrix solution includes the following steps: A1. Control the mass ratio of dried ginseng, dried Chinese yam and soy protein isolate to 2:3:6. Mix the dried ginseng, dried Chinese yam and soy protein isolate and place them in an air jet mill. Grind for 10 minutes under the conditions of 0.8MPa pressure and 4000rpm classifier speed. The particle size D90 < 15μm is obtained to obtain mixed medicinal powder. A2. Control the mass ratio of mixed medicinal powder, distilled water, neutral protease and flavor protease to 100:900:1.0:0.5. Mix the mixed medicinal powder and distilled water, keep it at 95℃ for 15 minutes for high-temperature gelatinization, cool it down to 55℃, add neutral protease and flavor protease, stir at 200 rpm for 2 hours. After the reaction is completed, the enzymatic hydrolysate is obtained. A3. Control the mass ratio of glucose to enzymatic hydrolysate to 4:100. Add glucose to the enzymatic hydrolysate and adjust the pH of the system to 7.5 using 10wt% sodium bicarbonate aqueous solution. Stir the reaction at 105℃ and 200rpm for 20min. After the reaction is completed, homogenize the solution three times under a pressure of 25MPa to obtain yam-ginseng matrix solution. Cool the solution to 4℃ for later use. The preparation method of the biological carrier includes the following steps: B1. The mass ratio of Poria cocos powder, cellulase, β-glucanase and distilled water was controlled at 100:1:1:1000. The Poria cocos powder was dispersed in distilled water, and the pH of the system was adjusted to 6.0 using 10wt% citric acid aqueous solution. Cellulase and β-glucanase were added, and the enzymatic hydrolysis reaction was carried out at 60℃ and 250rpm for 1.5h. After the reaction was completed, the temperature was raised to 100℃ to inactivate the enzyme for 10min, and centrifuged at 5000rpm for 10min. The solid was washed three times with distilled water and placed in a vacuum drying oven. It was dried to constant weight under vacuum of -0.095MPa and temperature of 55℃. The dried solid was pulverized using an air jet mill and passed through an 800-mesh sieve to obtain modified Poria cocos microparticles with a particle size of 20μm. B2. Control the mass ratio of ginseng extract, modified Poria cocos microparticles and sodium alginate aqueous solution to 1:5:25. Dissolve ginseng extract in sodium alginate aqueous solution with a mass fraction of 2.0%, add modified Poria cocos microparticles, and stir for 30 minutes at room temperature and 500 rpm to form a mixed slurry. B3. Control the mass ratio of the mixed slurry and the calcium lactate aqueous solution to 1:10. At room temperature and 100 rpm, add the mixed slurry to a 3.0% calcium lactate aqueous solution and continue stirring for 20 min. Let it stand and solidify for 20 min. Filter using a 250-mesh filter. Wash the solid with distilled water three times to obtain wet granules. B4. Control the mass ratio of chitosan, acetic acid aqueous solution, and wet particles to 1.5:100:35. Add chitosan to the acetic acid aqueous solution and stir for 2 hours at room temperature and 400 rpm until completely dissolved. Adjust the pH of the system to 5.0 using 1 wt% sodium hydroxide solution to obtain a chitosan-acetic acid solution. Immerse the wet particles in the chitosan-acetic acid solution and continue stirring for 10 minutes. Filter using a 200-mesh filter. Wash the solid with distilled water until the washing liquid is neutral. Place it in a vacuum freeze dryer and freeze-dry at -56 0℃ for 36 hours to obtain the biological carrier. The preparation method of fruit and vegetable powder includes the following steps: C1. Control the mass ratio of cranberries, carrots, distilled water, pectinase, and cellulase to 60:50:120:0.2:0.2. Mix the washed and chopped carrots, cranberries, and distilled water, and then use a high-speed tissue homogenizer to homogenize at 7000 rpm for 3 minutes. Pass the mixture through a 70-mesh sieve to obtain fruit and vegetable pulp. Add pectinase and cellulase to the fruit and vegetable pulp, and adjust the pH of the system to 5.5 using a 10wt% citric acid aqueous solution. Enzymatically hydrolyze the mixture at 50℃ and 100 rpm for 1.5 hours. After enzymatic hydrolysis, obtain the enzymatically hydrolyzed pulp. C2. Control the mass ratio of mixed bacterial strains and enzymatic hydrolysate to 4:100. Add the mixed bacterial strains (the mass ratio of Lactobacillus plantarum and Leuconostoc mesenteroides is 1:1.2) to the enzymatic hydrolysate and ferment at 35℃ in a sealed environment for 24 hours. After fermentation, freeze-dry the mixture for 36 hours at a cold trap temperature of -50℃ and a vacuum degree of <100Pa until the moisture content is <5%. Under the condition of relative humidity of <40%, use an ultra-micro pulverizer with a circulating water-cooled jacket, set the pulverizer speed to 12000rpm, control the temperature inside the pulverizing chamber to 25℃ for pulverization, and pass it through a 120-mesh sieve to obtain fruit and vegetable powder. The artificial sweetener is composed of stachyose and trehalose in a mass ratio of 1:3; The compound fermentation agent is composed of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum and Bifidobacterium longum in an effective viable count ratio of 2.5:1.5:2.5:1; A fermented ginseng yogurt comprises the following ingredients in parts by weight: 90 parts raw milk, 25 parts yam-ginseng matrix liquid, 5 parts biological carrier, 8 parts fruit and vegetable powder, 5 parts sugar substitute, and 0.08 parts compound fermentation agent; A method for preparing fermented ginseng yogurt includes the following preparation steps: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.5% and a protein content of 3.2%. S2. Weigh out the raw milk, yam-ginseng matrix liquid, biological carrier, fruit and vegetable powder, sugar substitute and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 60°C, add the yam-ginseng matrix liquid and sugar substitute, and stir at 1200 rpm for 10 minutes to obtain the mixed liquid; S4. Heat the mixture to 65°C, perform high-pressure homogenization under the conditions of primary homogenization pressure of 22MPa and secondary homogenization pressure of 5MPa, raise the temperature to 95°C, pasteurize for 5 minutes, and then cool to 42°C for later use. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and biological carrier to the cooled liquid. Stir at 50 rpm for 5 minutes and place in a fermentation tank. First, ferment at 42℃ for 2.5 hours, and then continue fermentation at 37℃ until the lactic acidity reaches 80°T. After fermentation, cool to 20℃ through a tubular heat exchanger. After filling, let it stand at 6℃ for 18 hours to ripen and obtain fermented ginseng yogurt.

[0069] To verify the overall performance of the fermented ginseng yogurt in Examples 1-3 of this invention, the inventors set up Comparative Examples 1-6, as follows: Comparative Example 1 The difference between this comparative example and Example 1 is that step A3 is deleted. When preparing fermented ginseng yogurt, the yam-ginseng matrix liquid is replaced with the enzymatic hydrolysate prepared in step A2 in equal mass. The remaining steps and raw materials are the same as in Example 1. A fermented ginseng yogurt comprises the following ingredients in parts by weight: 80 parts raw milk, 15 parts enzymatic hydrolysate, 3 parts biological carrier, 5 parts fruit and vegetable powder, 4 parts sugar substitute, and 0.05 parts compound fermentation agent. A method for preparing fermented ginseng yogurt includes the following preparation steps: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.0% and a protein content of 2.8%. S2. Weigh out raw milk, enzyme hydrolysate, biological carrier, fruit and vegetable powder, sugar substitute and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 55°C, add the enzymatic hydrolysate and sugar substitute, and stir at 1000 rpm for 15 minutes to obtain a mixed liquid. S4. Heat the mixture to 60°C, perform high-pressure homogenization under the conditions of primary homogenization pressure of 18MPa and secondary homogenization pressure of 3MPa, raise the temperature to 90°C, pasteurize for 10 minutes, and then cool to 40°C for later use. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and biological carrier to the cooled liquid. Stir at 30 rpm for 10 min and place in a fermentation tank. First, ferment at 40℃ for 3.0 h, and then continue fermentation at 35℃ until the lactic acidity reaches 75°T. After fermentation, cool to 15℃ through a tubular heat exchanger. After filling, let stand at 4℃ for 24 h to ripen and obtain fermented ginseng yogurt.

[0070] Comparative Example 2 The difference between this comparative example and Example 1 is that in step S5, the biological carrier is replaced by a mixture of ginseng extract and modified Poria cocos microparticles, while the remaining steps and raw materials are the same as in Example 1. The method for preparing the mixture includes the following steps: B1. The mass ratio of Poria cocos powder, cellulase, β-glucanase and distilled water was controlled at 100:0.5:0.5:800. The Poria cocos powder was dispersed in distilled water, and the pH of the system was adjusted to 5.0 using 10wt% citric acid aqueous solution. Cellulase and β-glucanase were added, and the enzymatic hydrolysis reaction was carried out at 55℃ and 150rpm for 2.5h. After the reaction was completed, the temperature was raised to 90℃ to inactivate the enzyme for 15min, and centrifuged at 4000rpm for 15min. The solid was washed twice with distilled water and placed in a vacuum drying oven. It was dried to constant weight under vacuum of -0.08MPa and temperature of 50℃. The dried solid was pulverized using an air jet mill and passed through a 600-mesh sieve to obtain modified Poria cocos microparticles with a particle size of 10μm. B2. Control the mass ratio of ginseng extract and modified Poria cocos microparticles to 1:3, mix the ginseng extract and modified Poria cocos microparticles, and stir for 40 minutes at room temperature and 300 rpm to obtain a mixture. A fermented ginseng yogurt comprises the following ingredients in parts by weight: 80 parts raw milk, 15 parts yam-ginseng matrix liquid, 3 parts mixed ingredients, 5 parts fruit and vegetable powder, 4 parts sugar substitute, and 0.05 parts compound fermentation agent; A method for preparing fermented ginseng yogurt includes the following preparation steps: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.0% and a protein content of 2.8%. S2. Weigh out the raw milk, yam-ginseng matrix liquid, mixture, fruit and vegetable powder, sugar substitute and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 55°C, add the yam-ginseng matrix liquid and sugar substitute, and stir at 1000 rpm for 15 minutes to obtain the mixed liquid. S4. Heat the mixture to 60°C, perform high-pressure homogenization under the conditions of primary homogenization pressure of 18MPa and secondary homogenization pressure of 3MPa, raise the temperature to 90°C, pasteurize for 10 minutes, and then cool to 40°C for later use. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and mixture to the cooled liquid. Stir at 30 rpm for 10 minutes and place in a fermentation tank. First, ferment at 40℃ for 3.0 hours, and then continue fermentation at 35℃ until the lactic acidity reaches 75°T. After fermentation, cool to 15℃ through a tubular heat exchanger. After filling, let it stand at 4℃ for 24 hours to ripen and obtain fermented ginseng yogurt.

[0071] Comparative Example 3 The difference between this comparative example and Example 1 is that, in the preparation of the biological carrier, step B1 is deleted and the modified Poria cocos microparticles are replaced with Poria cocos powder of equal mass. The remaining steps and raw materials are the same as in Example 1. The preparation method of the biological carrier includes the following steps: B1. Control the mass ratio of ginseng extract, poria cocos powder and sodium alginate aqueous solution to 1:3:15. Dissolve ginseng extract in sodium alginate aqueous solution with a mass fraction of 1.5%, add poria cocos powder, and stir for 40 minutes at room temperature and 300 rpm to form a mixed slurry. B2. Control the mass ratio of the mixed slurry and the calcium lactate aqueous solution to 1:5. At room temperature and 80 rpm, add the mixed slurry to a 2.0% calcium lactate aqueous solution and continue stirring for 30 min. Let it stand and solidify for 30 min. Filter using a 200-mesh filter. Wash the solid twice with distilled water to obtain wet granules. B3. Control the mass ratio of chitosan, aqueous acetic acid solution, and wet particles to 1:100:25. Add chitosan to the aqueous acetic acid solution and stir for 4 hours at room temperature and 200 rpm until completely dissolved. Adjust the pH of the system to 4.5 using 1 wt% sodium hydroxide solution to obtain a chitosan-acetic acid solution. Immerse the wet particles in the chitosan-acetic acid solution and continue stirring for 15 minutes. Filter using a 100-mesh filter. Wash the solid with distilled water until the washing liquid is neutral. Place it in a vacuum freeze dryer and freeze dry at -40℃ for 48 hours to obtain the biological carrier.

[0072] Comparative Example 4 The difference between this comparative example and Example 1 is that in step S5, the fruit and vegetable powder is replaced with ordinary fruit and vegetable powder obtained by drying and pulverizing fruit and vegetable pulp. The remaining steps and raw materials are the same as in Example 1. The preparation method of fruit and vegetable powder includes the following steps: The mass ratio of blueberries, carrots, and distilled water was controlled at 50:40:100. The washed and chopped carrots, blueberries, and distilled water were mixed and then pulped using a high-speed tissue homogenizer at 6000 rpm for 5 minutes. The pulp was then passed through a 50-mesh sieve to obtain a fruit and vegetable pulp. The pulp was freeze-dried for 48 hours at a cold trap temperature of -45℃ and a vacuum degree of <100Pa until the moisture content was <5%. Under the condition of relative humidity of <40%, an ultrafine pulverizer with a circulating water-cooled jacket was used. The pulverizer speed was set at 8000 rpm and the temperature inside the pulverizing chamber was controlled at 30℃. The pulp was then passed through a 100-mesh sieve to obtain ordinary fruit and vegetable powder.

[0073] A fermented ginseng yogurt comprises the following ingredients in parts by weight: 80 parts raw milk, 15 parts yam-ginseng matrix liquid, 3 parts biological carrier, 5 parts ordinary fruit and vegetable powder, 4 parts sugar substitute, and 0.05 parts compound fermentation agent. A method for preparing fermented ginseng yogurt includes the following preparation steps: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.0% and a protein content of 2.8%. S2. Weigh out the raw milk, yam-ginseng matrix liquid, biological carrier, ordinary fruit and vegetable powder, sugar substitute and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 55°C, add the yam-ginseng matrix liquid and sugar substitute, and stir at 1000 rpm for 15 minutes to obtain the mixed liquid. S4. Heat the mixture to 60°C, perform high-pressure homogenization under the conditions of primary homogenization pressure of 18MPa and secondary homogenization pressure of 3MPa, raise the temperature to 90°C, pasteurize for 10 minutes, and then cool to 40°C for later use. S5. Under aseptic conditions, add compound fermentation agent, ordinary fruit and vegetable powder and biological carrier to the cooled liquid. Stir at 30 rpm for 10 min and place in a fermentation tank. First, ferment at 40℃ for 3.0 h, and then continue fermentation at 35℃ until the lactic acidity reaches 75°T. After fermentation, cool to 15℃ through a tubular heat exchanger. After filling, let stand at 4℃ for 24 h to ripen and obtain fermented ginseng yogurt.

[0074] Comparative Example 5 The difference between this comparative example and Example 1 is that, in the preparation of fermented ginseng yogurt, the sugar substitute is replaced with white sugar, while the remaining steps and raw materials are the same as in Example 1. A fermented ginseng yogurt comprises the following ingredients in parts by weight: 80 parts raw milk, 15 parts yam-ginseng matrix liquid, 3 parts biological carrier, 5 parts fruit and vegetable powder, 4 parts white sugar, and 0.05 parts compound fermentation agent. A method for preparing fermented ginseng yogurt includes the following preparation steps: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.0% and a protein content of 2.8%. S2. Weigh out the raw milk, yam-ginseng matrix liquid, biological carrier, fruit and vegetable powder, white sugar and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 55°C, add the yam-ginseng matrix liquid and white sugar, and stir at 1000 rpm for 15 minutes to obtain the mixed liquid. S4. Heat the mixture to 60°C, perform high-pressure homogenization under the conditions of primary homogenization pressure of 18MPa and secondary homogenization pressure of 3MPa, raise the temperature to 90°C, pasteurize for 10 minutes, and then cool to 40°C for later use. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and biological carrier to the cooled liquid. Stir at 30 rpm for 10 min and place in a fermentation tank. First, ferment at 40℃ for 3.0 h, and then continue fermentation at 35℃ until the lactic acidity reaches 75°T. After fermentation, cool to 15℃ through a tubular heat exchanger. After filling, let stand at 4℃ for 24 h to ripen and obtain fermented ginseng yogurt.

[0075] Comparative Example 6 The difference between this comparative example and Example 1 is that in step S5, the variable temperature fermentation is changed to constant temperature fermentation, while the remaining steps and raw materials are the same as in Example 1. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and biological carrier to the cooled liquid. Stir at 30 rpm for 10 min, place in a fermentation tank, and ferment at 42℃ until the lactic acidity reaches 75°T. Stop fermentation, cool to 15℃ through a tubular heat exchanger, fill and let stand at 4℃ for 24 h to ripen, and obtain fermented ginseng yogurt.

[0076] Performance testing I. Basic Physicochemical Indicators 1. Viscosity A BROOKFIELD DV2T viscometer was used. The yogurt sample was warmed to 20±1℃, gently stirred, and then placed in a measuring cup. A suitable rotor was selected, and the viscosity was measured after stable shearing at 10 rpm for 30 seconds. Each sample was measured in triplicate, and the average value was taken. The unit is mPa·s.

[0077] 2. Water Holding Capacity (WHC) Weigh 30g of yogurt sample into a 50mL centrifuge tube and record the sample mass M1. Centrifuge at 4℃ and 3000xg for 20min. Invert the centrifuge tube for 10min to discard all whey and weigh it, recording the weight as M2. Perform three parallel measurements for each sample and take the average value. Calculate the water holding capacity (%) using the formula: water holding capacity (%) = (M2 / M1) × 100.

[0078] 3. Whey separation rate (Syneresis Rate) Weigh 30g of yogurt sample into a 50mL centrifuge tube, record the sample mass M1, and centrifuge at 4℃ and 3000xg for 20min. After centrifugation, carefully pour the supernatant whey into a pre-weighed container and weigh it to obtain the whey mass M. w Each sample was measured in triplicate, and the average value was taken. The calculation formula is: Whey separation rate (%) = (M) / (M) w / M1)×100.

[0079] The specific test results are shown in Table 1.

[0080] Table 1: Basic Physicochemical Indicators of Different Yogurt Samples As shown in Table 1 above, the fermented ginseng yogurt prepared in Examples 1-3 of this invention exhibits excellent physicochemical stability in terms of viscosity, water holding capacity, and whey separation rate, which is significantly better than that of Comparative Examples 1-6.

[0081] Compared with the data shown in Example 1: Comparative Example 1, which did not undergo Maillard reaction treatment, showed a significant decrease in water-holding capacity and an increase in whey separation rate, indicating that the pyrazines and protein-polysaccharide complexes generated by the Maillard reaction have a significant effect on improving the stability of the milk system; Comparative Example 2, which did not use a biological carrier, and Comparative Example 3, which used unmodified Poria cocos powder, showed a decrease in water-holding capacity and an increase in whey separation, proving that the porous carrier constructed from modified Poria cocos microparticles and its surface calcium alginate gel coating structure can effectively prevent particle sedimentation and whey separation; Comparative Example 4, which used unfermented fruit and vegetable powder, and Comparative Example 5, which used white sugar, both showed poor system stability, indicating that the microbial fermentation treatment of fruit and vegetable powder and the compound use of sugar substitutes have a synergistic optimization effect on the system texture; Comparative Example 6, which underwent isothermal fermentation, showed a significant increase in whey separation rate, proving that the three-stage variable-temperature fermentation process helps to form a more stable protein gel network by regulating the metabolism of the microbial community and enzyme activity.

[0082] II. Sensory Quality Evaluation A total of 20 tasters conducted sensory evaluations of the yogurt samples, including 10 R&D experts from the food and beverage industry and 10 consumers. The yogurt samples were refrigerated at 4°C and then allowed to warm to room temperature for 15 minutes before being presented with randomized numbers. The tasters scored the samples according to the following criteria across five dimensions (20 points per dimension, total 100 points). The specific scoring criteria and results are shown in Tables 2 and 3.

[0083] Table 2: Sensory Descriptions and Scoring Criteria for Samples Table 3: Sensory evaluation results of different yogurt samples As shown in Table 3 above, the fermented ginseng yogurt prepared in Examples 1-3 of this invention is significantly superior to that in Comparative Examples 1-6 in terms of color, aroma, texture, taste and mouthfeel.

[0084] III. Content and Conversion Rate of Rare Ginsenosides (CK) 1. Sample preparation: Weigh 5g of yogurt sample into a 50mL centrifuge tube, add 20mL of 70% methanol solution, and sonicate for 40min at 300W power, 40kHz frequency and 30℃. After extraction, place the sample in a high-speed refrigerated centrifuge and centrifuge for 15min at 8000rpm and 4℃. Take the supernatant and filter it through a 0.22μm filter membrane for later use.

[0085] 2. HPLC analysis: A C18 column was used with acetonitrile-water as the mobile phase and gradient elution. The detection wavelength was 203 nm. The contents of major ginsenosides (Rb1, Rg1, etc.) and rare ginsenoside CK were quantified by external standard method.

[0086] 3. Conversion rate calculation: The conversion rate of rare ginsenoside CK in the fermented samples was calculated using the original ginsenoside Rb1 loaded in the biological carrier of Example 1 as a reference.

[0087] Conversion rate calculation formula: Conversion rate (%) = (CK content / initial Rb1 content) × 100.

[0088] The specific test results are shown in Table 4.

[0089] Table 4: Content and Conversion Rate of Rare Ginsenosides (CK) in Different Samples As shown in Table 4 above, the fermented ginseng yogurt prepared in Examples 1-3 of this invention has significantly increased content of rare ginsenosides (CK) and significantly decreased content of macromolecular ginsenoside Rb1, indicating that effective biotransformation of ginsenosides occurred during fermentation.

[0090] In summary, the comprehensive analysis of stability indicators, conversion efficiency of rare ginsenosides, and sensory evaluation results shows that this invention significantly improves the gel structure stability and sensory quality of fermented ginseng yogurt through the synergistic effect of biological carrier construction, composite homogenization process, and three-stage variable temperature fermentation, achieving efficient bioconversion of ginsenosides to rare active forms.

[0091] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A fermented ginseng yogurt, characterized in that, The ingredients include the following parts by weight: 80-90 parts raw milk, 15-25 parts yam-ginseng matrix liquid, 3-5 parts biological carrier, 5-8 parts fruit and vegetable powder, 4-5 parts sugar substitute, and 0.05-0.08 parts compound fermentation agent.

2. The fermented ginseng yogurt according to claim 1, characterized in that, The preparation method of the yam-ginseng matrix solution includes the following steps: A1. After mixing dried ginseng, dried Chinese yam and soy protein isolate, place them in an air jet mill for ultra-fine grinding. The particle size D90 < 15 μm is pulverized to obtain mixed medicinal powder. A2. Mix the mixed medicinal powder and distilled water, gelatinize at high temperature, cool to 50-55℃, add neutral protease and flavor protease, stir to react, and after the reaction is completed, obtain the enzymatic hydrolysate. A3. Add glucose to the enzymatic hydrolysate, adjust the pH of the system to 6.5-7.5, stir the reaction, and after the reaction is completed, perform high-pressure homogenization to obtain yam-ginseng matrix solution.

3. The fermented ginseng yogurt according to claim 1, characterized in that, The method for preparing the biological carrier includes the following steps: B1. Disperse Poria cocos powder in distilled water, adjust the pH of the system to 5.0-6.0, add cellulase and β-glucanase to carry out enzymatic hydrolysis reaction. After the reaction is completed, perform enzyme inactivation treatment, centrifuge, wash, dry, pulverize and sieve to obtain modified Poria cocos microparticles. B2. Dissolve ginseng extract in sodium alginate aqueous solution, add modified Poria cocos microparticles, stir evenly to form a mixed slurry; B3. While stirring, add the mixed slurry to the calcium lactate aqueous solution, continue stirring until uniform, let stand and solidify for 20-30 minutes, filter and wash to obtain wet granules; B4. Add chitosan to an aqueous acetic acid solution and stir until completely dissolved. Adjust the pH of the system to 4.5-5.0 to obtain a chitosan-acetic acid solution. Immerse the wet particles in the chitosan-acetic acid solution and continue stirring until homogeneous. After filtration, washing, and drying, obtain the biological carrier.

4. The fermented ginseng yogurt according to claim 1, characterized in that, The method for preparing the fruit and vegetable powder includes the following steps: C1. Mix washed and chopped carrots, fresh berries and distilled water and blend to obtain fruit and vegetable pulp. Add pectinase and cellulase to the fruit and vegetable pulp, adjust the pH of the system to 4.5-5.5, and carry out enzymatic hydrolysis. After the enzymatic hydrolysis is completed, the enzymatically hydrolyzed pulp is obtained. C2. Add the mixed bacterial culture to the enzymatic hydrolysate for anaerobic fermentation. After fermentation, dry, pulverize and sieve to obtain fruit and vegetable powder.

5. The fermented ginseng yogurt according to claim 4, characterized in that, In step C2, the mixed bacterial strains are Lactobacillus plantarum and Leuconostoc mesenteroides in a mass ratio of 1:1-1.

2.

6. The fermented ginseng yogurt according to claim 1, characterized in that, The sugar substitute is composed of stachyose and trehalose in a mass ratio of 1:2-3.

7. The fermented ginseng yogurt according to claim 1, characterized in that, The compound fermentation agent is composed of Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus plantarum and Bifidobacterium longum in an effective live bacteria ratio of 1.5-2.5:1-1.5:1.5-2.5:

1.

8. A method for preparing fermented ginseng yogurt according to any one of claims 1-7, characterized in that, The preparation steps include the following: S1. Standardize the inspected and qualified raw milk to achieve a fat content of 3.0%-3.5% and a protein content of 2.8%-3.2%. S2. Weigh out the raw milk, yam-ginseng matrix liquid, biological carrier, fruit and vegetable powder, sugar substitute and compound fermentation agent by weight and set aside. S3. Heat the raw milk to 55-60℃, add the yam-ginseng base liquid and sugar substitute, stir well to obtain the mixed liquid; S4. Heat the mixture to 60-65℃, homogenize under high pressure, pasteurize, and then cool to 40-42℃ for later use. S5. Under aseptic conditions, add compound fermentation agent, fruit and vegetable powder and biological carrier to the cooled liquid, stir evenly, and then carry out variable temperature fermentation. After fermentation, cool to 15-20℃, fill into bottles and let stand at 4-6℃ for 18-24 hours to ripen, and obtain fermented ginseng yogurt.

9. The method for preparing fermented ginseng yogurt according to claim 8, characterized in that, In step S4, high-pressure homogenization refers to high-pressure homogenization performed under the conditions of a first-stage homogenization pressure of 18-22 MPa and a second-stage homogenization pressure of 3-5 MPa.

10. The method for preparing fermented ginseng yogurt according to claim 8, characterized in that, In step S5, the variable temperature fermentation refers to: first fermenting at a temperature of 40-42℃ for 2.5-3.0 hours, and then continuing fermentation at a temperature of 35-37℃ until the lactic acidity reaches 75-80°T.

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