Fermented milk containing lactobacillus kefiranofaciens and preparation method thereof

Abstract

The invention relates to the technical field of biology, in particular to fermented milk containing lactobacillus kefiranofaciens and a preparation method of the fermented milk. The fermented milk provided by the invention is prepared from lactobacillus kefiranofaciens, streptococcus thermophilus and raw milk, wherein the lactobacillus kefiranofaciens is lactobacillus kefiranofaciens XZ-54, and the preservation number is CGMCC (China General Microbiological Culture Collection Center) No.28448. The lactobacillus kefiranofaciens and the streptococcus thermophilus are compounded and combined and then fermented in the raw milk, proliferation and fermentation of the lactobacillus kefiranofaciens in a cow milk fermentation system are successfully achieved, the fermentation time of the lactobacillus kefiranofaciens in the cow milk fermentation system is greatly shortened, the fermentation time of the lactobacillus kefiranofaciens in the cow milk fermentation system is shortened, and the fermentation efficiency of the lactobacillus kefiranofaciens in the cow milk fermentation system is improved. The fermentation time is shortened from original 48 hours to 8-12 hours, and the viable count of the lactobacillus kefiranofaciens in the fermented milk can reach 10 < 8 > CFU / g or above.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, in particular to fermented milk containing kefir-like lactobacillus and a preparation method thereof. Background Art

[0002] Dairy products are an important part of the dietary structure of many countries and regions around the world. Traditionally, fermented dairy products such as yogurt rely mainly on single or a few bacteria for fermentation. However, with the advancement of scientific research and the development of technical means, the application of starter cultures in the dairy industry has shifted from traditional microorganisms to strains with specific functions. By synergizing the fermentation of starter cultures with excellent fermentation performance and specific probiotic functional strains to develop new fermented foods, it is possible to achieve the diversification of the flavor, taste, and nutritional and health effects of fermented milk, and to meet the needs of specific consumer groups, providing new ideas and methods for the development of food industry bacteria with independent intellectual property rights.

[0003] Kühm Lactobacillus has been shown to have a variety of probiotic effects such as antibacterial and antioxidant effects, but it grows slowly in milk, which greatly limits its industrial application. Different strains require different nutritional tolerances, such as yeast powder, soy protein, soy peptone or hydrolyzed soy protein to promote the growth of Lactobacillus plantarum in cow's milk, but these proliferation factors will make the resulting product have a poor flavor. There is currently no research on the proliferation of Kühm Lactobacillus. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a fermented milk containing kefir-like Lactobacillus and a preparation method thereof, so as to solve the problems in the prior art.

[0005] To achieve the above object and other related objects, the present invention provides a fermented milk, wherein the fermented milk is prepared from Lactobacillus kumiss, Streptococcus thermophilus and raw milk.

[0006] Preferably, the kefir-like Lactobacillus is kefir-like Lactobacillus XZ-54, and its deposit number is CGMCC No.28448.

[0007] The present invention also provides a method for preparing the fermented milk, which comprises the following steps: inoculating Lactobacillus kumiss into raw milk added with Streptococcus thermophilus for fermentation to obtain the fermented milk.

[0008] As described above, the fermented milk containing kumis-like Lactobacillus and the preparation method thereof of the present invention have the following beneficial effects:

[0009] (1) The present invention successfully achieves the proliferation and fermentation of Kfushin-like Lactobacillus in a bovine milk fermentation system by combining Kfushin-like Lactobacillus with thermophilic Streptococcus and fermenting them in raw milk;

[0010] (2) The method of the present invention greatly shortens the fermentation time of kumiss-like Lactobacillus in the milk fermentation system, from the original fermentation time of 48 hours to 8-12 hours, so that the number of live bacteria of kumiss-like Lactobacillus in the fermented milk can reach 10 8 CFU / g and above. DETAILED DESCRIPTION

[0011] The invention provides a fermented milk, which is prepared from kefir-like lactobacillus, thermophilic streptococcus and raw milk.

[0012] In some specific embodiments, the kumiss-like Lactobacillus is kumiss-like Lactobacillus XZ-54 (Lactobacillus kefiranofaciens subsp. kefiranofaciens), and the preservation number of the kumiss-like Lactobacillus XZ-54 is CGMCC No. 28448, which is deposited in the General Microbiology Center of the China Culture Collection Administration CGMCC, the preservation time is 2023.09.13, and the preservation address is the Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.

[0013] In some specific embodiments, the thermophilic Streptococcus is selected from one or more of thermophilic Streptococcus XJ53, thermophilic Streptococcus ST1, and thermophilic Streptococcus STM1.

[0014] Furthermore, Streptococcus thermophilus XJ53, Streptococcus thermophilus ST1, and Streptococcus thermophilus STM1 all come from the strain bank of Bright Dairy Research Institute, among which the preservation number of Streptococcus thermophilus XJ53 is CGMCC No.17323, and it is deposited in the General Microbiology Center of China Culture Collection of Microorganisms CGMCC, the preservation date is 2019.03.08, and the preservation address is the Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.

[0015] In some specific embodiments, the raw milk is fresh milk and / or reconstituted milk.

[0016] Furthermore, the fat content of the raw milk is not less than 3.1% of the total mass of the raw milk, the protein content is not less than 2.8% of the total mass of the raw milk, and the non-fat milk solids content is not less than 8.1% of the total mass of the raw milk.

[0017] In some specific embodiments, based on the volume of the fermented milk, the amount of the added Lactobacillus kumiss is 1.0×10 7 CFU / mL and above.

[0018] In some specific embodiments, based on the volume of the fermented milk, the amount of the thermophilic Streptococcus added is 1×10 5-1×10 9 CFU / mL. Specifically, the added amount is 1×10 5 -1×10 6 , 1×10 6 -5×10 6 , 5×10 6 -1×10 7 , 1×10 7 -5×10 7 , 5×10 7 -1×10 8 or 1×10 8 -1×10 9 CFU / mL. Preferably, the added amount is 5×10 6 -5×10 7 CFU / mL.

[0019] The present invention also provides a method for preparing the fermented milk, which comprises the following steps: inoculating Lactobacillus kumiss into raw milk to which Streptococcus thermophilus is added and fermenting the raw milk to obtain the fermented milk.

[0020] In some specific embodiments, the preparation method comprises the following steps:

[0021] 1) mixing raw milk and sweetener to obtain liquid 1;

[0022] 2) After homogenizing, sterilizing and cooling the feed liquid 1, the feed liquid 2 is obtained:

[0023] 3) The feed liquid 2 is mixed with thermophilic Streptococcus and krumel-like Lactobacillus and fermented to obtain the aforementioned fermented milk.

[0024] In some embodiments, the sweetener in step 1) is sugar.

[0025] In some specific embodiments, the mixing time in step 1) is 5-60 min. Specifically, the mixing time is 5-10, 10-15, 15-20, 20-25, 25-30, 30-40, 40-50 or 50-60 min. Preferably, the mixing time is 10-30 min.

[0026] In some specific embodiments, the mixing temperature in step 1) is 30-65° C. Specifically, the mixing temperature is 30-35, 35-40, 40-45, 45-50, 50-55, 55-60, 60-65° C. Preferably, the mixing temperature is 40-55° C.

[0027] In some specific embodiments, the homogenization step in step 2) is one or more stages. Preferably, the homogenization step is divided into two stages, wherein the temperature of the first stage homogenization is 60-70°C and the pressure is 15-20MPa, and the temperature of the second stage homogenization is 60-70°C and the pressure is 2-5MPa.

[0028] In some specific embodiments, the sterilization temperature in step 2) is 75-105°C and the time is 1-15 min. Specifically, the sterilization temperature is 75-80-80-85, 85-90, 90-95, 95-100 or 100-105°C; the sterilization time is 1-3, 3-5, 5-10 or 10-15 min. Preferably, the sterilization temperature is 85-95°C and the time is 5-10 min.

[0029] In some specific embodiments, the temperature after cooling in step 2) is 20-40° C. Specifically, the temperature after cooling is 20-25, 25-30, 30-33, 33-35, 35-37 or 37-40° C. Preferably, the temperature after cooling is 30-37° C.

[0030] In some specific embodiments, the mixing time in step 3) is 1-15 min. Specifically, the mixing time is 1-3, 3-5, 5-10 or 10-15 min. Preferably, the mixing time is 5-10 min.

[0031] In some specific embodiments, in step 3), the fermentation temperature is 20-40°C, the fermentation time is 4-16h, and the acidity at the end of the fermentation is 60-80°T. Specifically, the fermentation temperature is 20-25, 25-30, 30-33, 33-35, 35-37 or 37-40°C; the fermentation time is 4-6, 6-8, 8-10, 10-12, 12-14 or 14-16h; the acidity at the end of the fermentation is 60-65, 65-70, 70-75 or 75-80°T. Specifically, the fermentation temperature is 30-37°C, the fermentation time is 8-12h, and the acidity at the end of the fermentation is 6575°T.

[0032] In some specific embodiments, in step 3), a demulsification step and / or a tank turning step are further provided after fermentation.

[0033] Furthermore, the cylinder turning is a back-pressure cylinder turning.

[0034] Furthermore, the pressure of the back pressure overturning cylinder is 0.3-0.5MPa. Specifically, the pressure of the back pressure overturning cylinder is 0.3-0.4 or 0.4-0.5MPa.

[0035] In the present invention, the term "reconstituted milk" refers to a liquid milk product obtained by reconstituted a dairy product such as skim milk powder or whole milk powder into a milk component similar to that of the original milk by adding an appropriate amount of water.

[0036] In the present invention, the term "emulsification step" refers to a step in which, after the fermentation process is completed, the curd structure formed by fermentation is broken up by stirring or other means to make it smaller particles, thereby improving the organizational state and taste of the product.

[0037] In the present invention, the term "tank turning step" refers to the process of transferring the fermented milk from the fermentation tank to another container for cooling after the fermented milk reaches the end of fermentation. The purpose of this step is to terminate the fermentation and prevent over-fermentation by lowering the temperature, and it can also improve the texture and taste of the product.

[0038] In the present invention, the term "back pressure tank turning" refers to the process of subjecting the yogurt to a certain back pressure during the tank turning and conveying process to make its texture more uniform and delicate.

[0039] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0040] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing the specific embodiments rather than for limiting the scope of protection of the present invention; in the present specification and claims, unless otherwise expressly stated herein, the singular forms "a", "an" and "the" include plural forms.

[0041] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0042] Example 1

[0043] Raw material formula: 93% raw milk, 7% white sugar, Streptococcus thermophilus XJ53 (3×107 CFU / g raw material), Kfu-like Lactobacillus XZ54 (3×10 7 CFU / g raw milk).

[0044] Preparation method:

[0045] 1. Ingredients: Dissolve white sugar in 40°C raw milk and stir for 15 minutes.

[0046] 2. Homogenization: total pressure is 20MPa, primary pressure is 15MPa, secondary pressure is 5MPa; temperature is 60℃.

[0047] 3. Sterilization: 90℃, 10 minutes.

[0048] 4. Cooling: After sterilization, cool the liquid to 37°C.

[0049] 5. Fermentation: Add thermophilic Streptococcus and kumiss-like Lactobacillus, ferment at 37°C for 12 hours, and the end point pH value is pH = 4.7.

[0050] 6. Turn over the tank and cool it down to 10℃.

[0051] 7. Post-ripening in the refrigerator: Ripen at 2℃-6℃ for more than 12 hours.

[0052] Example 2

[0053] Raw material formula: raw milk 93%, white sugar 6.148%, thermophilic Streptococcus ST1 (3×10 7 CFU / g raw material), Kfu-like Lactobacillus XZ54 (3×10 7 CFU / g raw milk).

[0054] Preparation method:

[0055] 1. Ingredients: Dissolve white sugar in raw milk at 45°C and stir for 12 minutes.

[0056] 2. Homogenization: total pressure is 22MPa, primary pressure is 20MPa, secondary pressure is 2MPa; temperature is 65℃.

[0057] 3. Sterilization: 85℃, 15 minutes.

[0058] 4. Cooling: After sterilization, cool the liquid to 37°C.

[0059] 5. Fermentation: Add thermophilic Streptococcus and kumiss-like Lactobacillus, ferment at 37°C for 12 hours, and the end point pH value is pH = 4.7.

[0060] 6. Turn over the tank and cool it down to 10℃.

[0061] 7. Post-ripening in the refrigerator: Ripen at 2℃-6℃ for more than 12 hours.

[0062] Example 3

[0063] Raw material formula: 93% raw milk, 6.148% white sugar, Streptococcus thermophilus.00XJ53+ST1+STM1 (3×10 7 CFU / g raw material, the ratio between strains was 1:1:1), Kfu-like Lactobacillus XZ54 (3×10 7 CFU / g raw milk).

[0064] Preparation method:

[0065] 1. Ingredients: Dissolve white sugar in 50℃ raw milk and stir for 10 minutes.

[0066] 2. Homogenization: total pressure is 19MPa, primary pressure is 16MPa, secondary pressure is 3MPa; temperature is 60℃.

[0067] 3. Sterilization: 90℃, 10 minutes.

[0068] 4. Cooling: After sterilization, cool the liquid to 37°C.

[0069] 5. Fermentation: Add thermophilic Streptococcus and kumiss-like Lactobacillus, ferment at 37°C for 12 hours, and the end point pH value is pH = 4.7.

[0070] 6. Turn over the tank and cool it down to 10℃.

[0071] 7. Filling and sealing: After cooling, fill the container under the prescribed hygiene requirements and add kefir flavor online.

[0072] 8. Post-ripening in the refrigerator: Ripen at 2℃-6℃ for more than 12 hours.

[0073] Comparative Example 1

[0074] Thermophilus Streptococcus was not added, and the other procedures were the same as in Example 1.

[0075] Effect Example 1 Microbiological indicators of fermented milk before leaving the factory

[0076] Table 1

[0077] Microbial CFU / g Example 1 Example 2 Example 3 Comparative Example 1 Streptococcus thermophilus <![CDATA[2.58×10 8 ]]> <![CDATA[2.33×10 8 ]]> <![CDATA[3.11×10 8 ]]> / Lactobacillus kefir <![CDATA[2.18×10 8 ]]> <![CDATA[2.42×10 8 ]]> <![CDATA[4.25×10 7 ]]> <![CDATA[3.1×10 7 ]]> Increase multiple 7.03 7.80 13.71 /

[0078] The viable counts of thermophilic Streptococcus and krumel-like Lactobacillus in Examples 1-3 in Table 1 were all above 10 8 There was no significant difference above CFU / g; compared with the control group, the number of live bacteria of Kfusobacterium kumiss increased by more than 7-13 times.

[0079] Effect Example 2 Stability Observation Experiment of Fermented Dairy Products during Shelf Life

[0080] The samples prepared in Examples 1-3 of the present invention were stored at 4°C to 10°C and the viscosity was monitored over four weeks. The experimental results are recorded in Table 2 below.

[0081] Table 2

[0082]

[0083] The results of the stability experiment show that the pH value and viscosity of Examples 1-3 are stable after storage for 4 weeks, indicating that the product has good stability.

[0084] Effect Example 3 Sensory Evaluation

[0085] The products produced in Examples 1-3 were subjected to taste and flavor evaluation experiments. The sensory inspection items were: appearance, tissue state, taste, flavor, and sweetness and sourness. A total of 20 people participated in the experiment and performed sensory evaluation on the samples of Examples 1-3. The sensory scoring criteria are shown in Table 3 below, and the experimental results are recorded in Table 4.

[0086] Table 3

[0087] Rating items Scoring Criteria Score Appearance The surface is flat and smooth, and the product color is uniform and milky white 10 Organization Status Good tissue condition, normal viscosity, no whey precipitation 10 Taste Delicate and smooth, no powdery feeling 10 Flavor Cheese aroma 10 Sweetness and sourness Proper sweet and sour ratio 10 Total score 50

[0088] Table 4

[0089]

[0090] The sensory evaluation results show that the three examples of the present invention have good appearance and texture, full and smooth taste, and no powdery feeling. In terms of flavor, the present invention prepares a product with good flavor, rich cheese flavor, and good sourness and sweetness by selecting the strain and inoculation amount and controlling the fermentation temperature.

[0091] The above examples are for the purpose of illustrating the embodiments disclosed by the present invention and are not to be construed as limiting the present invention. In addition, the various modifications listed herein and the variations of the methods in the invention are obvious to those skilled in the art without departing from the scope and spirit of the present invention. Although the present invention has been specifically described in conjunction with various specific preferred embodiments of the present invention, it should be understood that the present invention should not be limited to these specific embodiments. In fact, various modifications as described above that are obvious to those skilled in the art to obtain the invention should be included within the scope of the present invention.

Claims

1. A fermented milk, characterized in that: The fermented milk is prepared from kefir-like lactobacillus, thermophilic streptococcus and raw milk.

2. The fermented milk according to claim 1, characterized in that The kumis Lactobacillus is kumis Lactobacillus XZ-54 (Lactobacillus kefiranofaciens subsp. kefiranofaciens), and its deposit number is CGMCC No.28448.

3. The fermented milk according to claim 1, characterized in that The thermophilic streptococcus is selected from one or more of thermophilic streptococcus XJ53, thermophilic streptococcus ST1 and thermophilic streptococcus STM1.

4. The fermented milk according to claim 1, characterized in that The raw milk is fresh milk and / or reconstituted milk.

5. The fermented milk according to claim 1, characterized in that The fat content of the raw milk is not less than 3.1% of the total mass of the raw milk, the protein content is not less than 2.8% of the total mass of the raw milk, and the non-fat milk solid content is not less than 8.1% of the total mass of the raw milk.

6. The fermented milk according to claim 1, characterized in that Based on the volume of the fermented milk, the amount of the kumiss-like Lactobacillus added is 1.0×10 7 CFU / mL and above.

7. The fermented milk according to claim 1, characterized in that Based on the volume of the fermented milk, the amount of the thermophilic streptococcus added is 1×10 5 -1×10 9 CFU / mL.

8. The method for preparing fermented milk according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: inoculating kefir-like lactobacillus into raw milk added with thermophilic streptococcus for fermentation to obtain the fermented milk.

9. The preparation method according to claim 8, characterized in that: The preparation method comprises the following steps: 1) mixing raw milk and sweetener to obtain liquid 1; 2) After homogenizing, sterilizing and cooling the feed liquid 1, the feed liquid 2 is obtained: 3) The feed liquid 2 is mixed with thermophilic streptococcus and krumel-like lactobacillus and fermented to obtain the fermented milk.

10. The preparation method according to claim 9, characterized in that: The preparation method also includes one or more of the following features: 1) The mixing time in step 1) is 5-60 min; 2) The mixing temperature in step 1) is 30-65°C; 3) The homogenization step in step 2) is one or more stages; preferably, the homogenization step is divided into two stages, wherein the temperature of the first stage homogenization is 60-70°C and the pressure is 15-20MPa, and the temperature of the second stage homogenization is 60-70°C and the pressure is 2-5MPa; 4) The sterilization temperature in step 2) is 75-105°C and the time is 1-15 minutes; 5) The temperature after cooling in step 2) is 20-40°C; 6) The mixing time in step 3) is 1-15 min; 7) In step 3), the fermentation temperature is 20-40°C, the fermentation time is 4-16 hours, and the acidity at the end of the fermentation is 60-80°T; 8) After fermentation in step 3), a demulsification step and / or a tank turning step are further provided.

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