Streptococcus thermophilus, plateau characteristic fermentation flavor powder and preparation and application thereof

Abstract

The invention relates to the technical field of food processing, in particular to streptococcus thermophilus, plateau special fermentation flavor powder and preparation and application thereof. The preservation number of the streptococcus thermophilus Linzhi.ST-1537 disclosed by the invention is CCTCC (China Center for Type Culture Collection) NO: M 2025782, and the preservation number of the streptococcus thermophilus Linzhi.ST-1537 disclosed by the invention is CCTCC NO: M 2025782. The plateau characteristic fermented flavor powder prepared from the strain disclosed by the invention is prepared by fermenting the following raw materials in parts by mass: 850-900 parts of raw milk, 60-100 parts of white granulated sugar, 40-50 parts of water and 0.06-0.08 part of a leavening agent. The fermented flavor powder can be used for preparing bread, drinks and cat food. The flavor powder provided by the invention has relatively high protein content and lactic acid bacteria number, relatively low lactose content and good solubility.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a thermophilic streptococcus, a plateau-characteristic fermented flavor powder, and its preparation and application. Background Technology

[0002] Fermented milk with lactic acid bacteria, as a nutrient-rich fermented dairy product, is favored by consumers of all ages due to its high content of protein, vitamins, and minerals. It is easily digestible and absorbable, regulates intestinal flora balance, enhances immunity, and addresses lactose intolerance caused by direct consumption of cow's milk in China. However, my country's fermented milk industry faces a dual bottleneck: ① The reliance on imported starter cultures for core bacterial strains leads to severe homogenization in flavor among domestic fermented milk products, resulting in vicious price competition and severely restricting product innovation. This also hinders the development of my country's distinctive fermented dairy industry. ② Product limitations, such as short shelf life (typically only about 21 days), low live bacteria survival rate, and the need for continuous cold chain storage, restrict market circulation and consumer convenience.

[0003] Compared to liquid fermented milk, fermented flavor powder has the following significant advantages: (1) it breaks through the cold chain restrictions, making it easier to transport and store; (2) it significantly extends the shelf life; (3) it has a wide range of applications, is easy to use, can be directly mixed, or used as a natural flavor enhancer in the food processing field. More importantly, fermented flavor powder retains the unique natural flavor substances and probiotic metabolites of fermented milk, making it not only a nutritional supplement but also a natural flavor improver for use in food processing fields such as baking, confectionery, and ice cream, which helps to develop "clean label" foods.

[0004] Chinese patent CN202411576027.5 discloses a fruit-flavored yogurt powder formula and its preparation method. By adding stabilizers, it improves the texture and stability of yogurt, reducing whey separation and coarsening of the texture, thus optimizing the fruit-flavored yogurt powder formula. This enhances the stability and quality of yogurt while maintaining its taste, preventing stratification or sedimentation during storage and transportation. Chinese patent CN202011600583.3 discloses a buttermilk powder and its preparation method, including the following steps: centrifuging light cream, collecting the lower aqueous phase, whipping and centrifuging it to obtain buttermilk, purifying the buttermilk through microfiltration, freezing, drying to obtain milk fat globule membrane powder, and storing it at low temperature. The milk fat globule membrane powder is then added to yogurt for fermentation and demulsification to obtain buttermilk powder. Chinese patent CN200810202072.9 discloses a homemade yogurt powder, comprising milk powder and probiotic powder, without adding any thickeners. It can be fermented at any time, is naturally pure, rich in nutrients, and can enhance human intestinal function.

[0005] The fermented flavor powder industry still faces many technical bottlenecks: First, the flavor is highly homogenized and monotonous, relying mainly on exogenous flavorings to compensate for the lack of fermented flavor; second, the products have problems such as poor mixing properties, incomplete dissolution, clumping, and abnormal color, which seriously affect the consumer experience; most importantly, the survival rate of probiotics is low during drying and storage, which greatly reduces the functionality of the products. Summary of the Invention

[0006] The technical problem solved by this invention: (1) Using the specific strains of this invention; (2) Excess lactose was removed, resulting in protein enrichment; (3) It improved the survival rate of lactic acid bacteria; (4) It has a unique flavor, good solubility, and a wide range of applications.

[0007] To address the aforementioned technical problems, this invention provides a method for preparing and applying a fermented flavor powder with plateau characteristics.

[0008] Specifically, the present invention provides the following technical solution: In a first aspect, the present invention provides a thermophilic streptococcus, wherein the thermophilic streptococcus is: thermophilic streptococcus ( 嗜热链球菌 Linzhi.ST-1537 was deposited at the China Center for Type Culture Collection on April 15, 2025, with accession number CCTCC NO:M 2025782.

[0009] Secondly, the present invention provides a plateau-characteristic fermented flavor powder, which, by weight, is obtained by fermenting raw materials comprising the following components: 850-900 parts raw milk, 60-100 parts white sugar, 40-50 parts water and 0.06-0.08 parts fermenting agent, wherein the fermenting agent is the thermophilic streptococcus Linzhi.ST-1537 and / or Lactobacillus delbrueckii subsp. Dangxiong LB VⅢ as described in claim 1.

[0010] Preferably, the flavor powder is obtained by fermentation of raw materials comprising the following components, in parts by weight: 870-900 parts raw milk, and / or 60-80 parts white sugar, and / or 40-45 parts water, and / or 0.06-0.07 parts starter culture; more preferably, the flavor powder is obtained by fermentation of raw materials comprising the following components, in parts by weight: 900 parts raw milk, and / or 60-65 parts white sugar, and / or 40-42 parts water, and / or 0.06 parts starter culture.

[0011] Preferably, the fermenting agent is a mixture of *Streptococcus thermophilus* Linzhi.ST-1537 and / or *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VIII; wherein, *Streptococcus thermophilus* Linzhi.ST-1537 or *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VIII is one or both; more preferably, the mass ratio of *Streptococcus thermophilus* Linzhi.ST-1537 to *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VIII is 1-3:1-3; more preferably, the mass ratio of *Streptococcus thermophilus* Linzhi.ST-1537 to *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VIII is 1-2:1-3; more preferably, the mass ratio of *Streptococcus thermophilus* Linzhi.ST-1537 to *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VIII is 1:1.

[0012] Preferably, the raw milk comprises raw milk and / or reconstituted milk obtained by dissolving milk powder in water at a concentration of 10-20 g / mL; more preferably, the raw milk is raw milk; more preferably, the concentration of the reconstituted milk is 15-20 g / mL; more preferably, the concentration of the reconstituted milk is 18-20 g / mL.

[0013] Preferably, the plateau-characteristic fermented flavor powder is obtained by fermenting, demulsifying, ripening, filtering and drying the raw materials.

[0014] Thirdly, the present invention provides a method for preparing a fermented flavor powder with plateau characteristics, comprising the following steps: (1) Add white sugar to the raw milk and mix evenly. Pasteurize the raw milk and add starter culture to the pasteurized raw milk for fermentation. After demulsification and post-ripening, the post-ripened fermented milk is obtained. (2) The fermented milk obtained in step (1) after ripening was filtered using a 0.01-0.1 μm ultrafiltration membrane to obtain the filtrate; (3) The filter material obtained in step (2) is dried to obtain flavor powder.

[0015] Preferably, in step (1), the fermentation temperature is 39-45℃; And / or, the fermentation time is 10-12 hours; and / or, the fermentation termination acidity is 110-130. 。 T.

[0016] Preferably, in step (1), the demulsification temperature is 15-25°C; And / or, the demulsification and standing time is 2-5 hours; and / or, the ripening time is 4-8 hours; and / or, the ripening temperature is 2-8°C.

[0017] Preferably, in step (2), a 0.01-0.05 μm ultrafiltration membrane is used to filter the fermented milk obtained in step (1) after ripening; more preferably, a 0.01 μm ultrafiltration membrane is used to filter the fermented milk obtained in step (1) after ripening.

[0018] Preferably, the filtration pressure in step (2) is 0.05-0.2 MPa; And / or, the filtration temperature is 2-6°C; and / or, the filtration is terminated when the volume of the filtered material is reduced to 45-55%.

[0019] Preferably, in step (3), the drying is carried out using low-temperature spray drying; more preferably, the drying temperature is 30-50°C; more preferably, the drying temperature is 35-50°C; and even more preferably, the drying temperature is 35-40°C.

[0020] Fourthly, the present invention provides a plateau-characteristic fermented flavor powder, which is prepared according to the above-mentioned preparation method.

[0021] Fifthly, the present invention provides a bread made from the above-mentioned plateau-characteristic fermented flavor powder or the plateau-characteristic fermented flavor powder obtained by the above-mentioned preparation method and bread ingredients.

[0022] Preferably, the bread ingredients include one or more of butter, egg liquid, powdered sugar and salt; and / or, by mass%, the flavor powder content in the bread is 1-12%.

[0023] Sixthly, the present invention provides a beverage made from the above-mentioned plateau-characteristic fermented flavor powder or the plateau-characteristic fermented flavor powder obtained by the above-mentioned preparation method and beverage ingredients.

[0024] Preferably, the flavor powder content in the beverage is 0.1-5% by mass; and / or, the beverage includes yogurt or tea. More preferably, the yogurt is made from the flavor powder, water, and milk; and / or, the tea is made from the flavor powder, water, milk, tea, dragon fruit, strawberry jam, and sugar.

[0025] In a seventh aspect, the present invention provides a cat food made from raw materials including the above-mentioned plateau-characteristic fermented flavor powder or the plateau-characteristic fermented flavor powder obtained by the above-mentioned preparation method.

[0026] Preferably, the flavor powder content in the cat food is 1-5% by mass.

[0027] Eighthly, the present invention provides an application of a plateau-characteristic fermented flavor powder in the food industry.

[0028] Beneficial effects of the present invention (1) Through the use of Lactobacillus delbrueckii subsp. Dangxiong LB VⅢ ( 德氏乳杆菌 亚种乳酸乳杆菌 Dangxiong LBVⅢ) and Streptococcus thermophilus ( 嗜热链球菌 Linzhi.ST-1537 is a fermentation strain that solves the problem of high cost of existing fermentation agents.

[0029] (2) By using membrane separation technology and low-temperature spray drying to treat fermented milk, excess lactose is removed, protein is enriched, the survival rate of lactic acid bacteria is improved, and it has a unique flavor. Attached Figure Description

[0030] Figure 1 This is a colony morphology diagram of Streptococcus thermophilus Linzhi.ST-1537.

[0031] Figure 2 Evaluation of the product application performance of the fermentation agent.

[0032] Figure 3A Comparative images of partial appearances of breads prepared using milk powder and highland-specific fermented flavor powder, respectively.

[0033] Figure 3B Comparison of the overall appearance of bread prepared using milk powder and highland-specific fermented flavor powder, respectively.

[0034] Figure 3C This is a bread filling prepared using fermented flavoring powder with a distinctive highland flavor.

[0035] Figure 4A A comparison image showing milk foam prepared using milk powder and a fermented flavoring powder with plateau characteristics.

[0036] Figure 4B A comparison image showing tea drinks prepared using milk powder and highland-specific fermented flavor powder, respectively.

[0037] Information on strain preservation The present invention provides *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VⅢ ( 德氏乳杆菌 亚种乳酸乳杆菌Dangxiong LBVⅢ was deposited on March 23, 2023, at the China Center for Type Culture Collection (CCTCC), accession number CCTCCNO:M 2023396, address: Wuhan University, Wuhan, China, postcode: 430072; telephone: (027) 68754052. This strain is disclosed in the patent publication document CN202311195562.1.

[0038] The thermophilic streptococcus provided by this invention ( 嗜热链球菌 The strain Linzhi.ST-1537 was deposited on April 15, 2025, at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC NO:M 2025782. The deposit address is: Wuhan University, Wuhan, China, 430072, China; telephone: (027) 68754052. Detailed Implementation

[0040] Current fermented flavor powders produced using existing technologies suffer from severe flavor homogenization and a lack of variety, relying primarily on exogenous flavorings to compensate for the absence of fermented flavor. Furthermore, they exhibit problems such as poor reconstitution, incomplete dissolution, clumping, and abnormal color, significantly impacting the consumer experience. Most importantly, the low survival rate of probiotics during drying and storage greatly diminishes the product's functionality. Therefore, this invention utilizes *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VⅢ and *Streptococcus thermophilus* Linzhi.ST-1537 as fermentation strains, employing membrane separation technology and low-temperature spray drying to process fermented milk. The aim is to provide a highland-specific fermented flavor powder and its preparation method, overcoming the bottleneck of reliance on imported starter cultures for the core strains. This process removes excess lactose, enriches proteins, improves probiotic survival rates, and enhances its unique flavor.

[0041] The fermenting agent used in this invention is one or both of Lactobacillus delbrueckii subsp. lactis Dangxiong LB VⅢ and Streptococcus thermophilus Linzhi.ST-1537.

[0042] The *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VⅢ used in this invention 德氏乳杆菌 亚种乳酸乳杆菌 Dangxiong LBVⅢ), was deposited at the China Center for Type Culture Collection (CCTCC) on March 23, 2023, with accession number CCTCCNO:M2023396, and is specifically disclosed in the patent specification CN202311195562.1.

[0043] The thermophilic streptococcus provided by this invention ( 嗜热链球菌The strain Linzhi.ST-1537 was deposited at the China Center for Type Culture Collection on April 15, 2025, with accession number CCTCC NO:M 2025782.

[0044] This invention provides a fermented flavor powder with plateau characteristics, the core preparation strain of which includes *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VⅢ. 德氏乳杆菌亚种乳酸乳杆菌 The preparation method of Dangxiong LBVⅢ or Streptococcus thermophilus Linzhi.ST-1537 includes the following steps: (1) Add white sugar to the raw milk and mix evenly. Pasteurize the raw milk and add starter culture to the pasteurized raw milk for fermentation. After demulsification and post-ripening, the post-ripened fermented milk is obtained. (2) The fermented milk obtained in step (1) after ripening was filtered using a 0.01-0.1 μm ultrafiltration membrane to obtain the filtrate; (3) The filter material obtained in step (2) is subjected to low-temperature spray drying.

[0045] This invention provides a thermophilic streptococcus ( 嗜热链球菌 The screening and identification method for Linzhi.ST-1537, wherein the MRS medium comprises 5-15 g / L peptone, 5-10 g / L beef extract, 2-6 g / L yeast extract, 15-25 g / L glucose, 1-5 g / L dipotassium hydrogen phosphate, 1-5 g / L diammonium hydrogen citrate, 2-8 g / L sodium acetate, 0.1-0.5 g / L magnesium sulfate, 0.02-0.08 g / L manganese sulfate, 10-15 g / L agar and 1-5 g / L Tween 80, wherein the pH value for culturing with the medium is 6.5±0.2 and the temperature for culturing with the medium is 33-40℃.

[0046] In some specific implementations, the following solutions are provided: The plateau-characteristic fermented flavor powder, by weight, is obtained through fermentation of raw materials comprising the following components: 850-900 parts raw milk, 60-100 parts white sugar, 40-50 parts water, and 0.06-0.08 parts starter culture. The preparation method of the plateau-characteristic fermented flavor powder includes the following steps: 1) Preparation of fermented milk: Pasteurize raw milk, white sugar and water, add starter culture to pasteurized raw milk, white sugar and water, and ferment at 39-45℃ for 10-12 hours. The fermentation is terminated at an acidity of 110-130°T to obtain fermented milk. 2) Demulsification: After fermentation is terminated, the fermented milk obtained in step (1) is demulsified by transferring it to another low-temperature tank. The temperature is lowered to 15-25°C and kept at this temperature for 2-5 hours to obtain demulsified fermented milk. Demulsification refers to transferring the demulsified fermented milk to another low-temperature tank. The purpose of demulsification is to reduce the viscosity of the fermented milk. Simply stir it to make its texture fine and smooth.

[0047] 3) Post-maturation: The fermented milk after demulsification in step (2) is transferred to a cold storage and allowed to mature for 4 to 8 hours at a temperature of 2 to 8℃ to obtain the post-maturated fermented milk; 4) Membrane separation: Using a 0.01-0.1μm ultrafiltration membrane, under the conditions of a pressure of 0.1 MPa and a temperature of 4℃, the fermented milk obtained in step (3) after ripening is circulated and filtered until the volume is reduced by 50% to obtain the filtered fermented milk; 5) Drying: The filtered fermented milk obtained in step (4) is dried using a low-temperature drying device.

[0048] To better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0049] Unless otherwise stated, all raw materials / reagents / instruments used in the embodiments of this invention are conventional commercially available products. Information on the sources of experimental materials used in this invention is shown in Table 1.

[0050] To better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0051] Example 1: Streptococcus thermophilus ( 嗜热链球菌 Screening and identification methods and results of Linzhi.ST-1537 Take 5 mL of naturally fermented yogurt from Langqiu Village, Songzong Town, Bomi County, Nyingchi City, Tibet Autonomous Region, and mix it with 45 mL of sterile physiological saline to obtain a concentration of 10. -1 Diluent, prepared according to this procedure, has a concentration of 10. -2 10 -3 10 -4 10 -5 and 10 -6 The diluted solution was spread onto MRS agar plates and incubated at 37°C for 48 hours. Typical colonies with different morphologies were picked and streaked onto MRS plates for isolation. The streaking was repeated twice until a single colony grew for observation of colony morphology.

[0052] The MRS medium comprises 10 g / L peptone, 8 g / L beef extract, 4 g / L yeast extract, 20 g / L glucose, 2 g / L dipotassium hydrogen phosphate, 2 g / L diammonium hydrogen citrate, 5 g / L sodium acetate, 0.2 g / L magnesium sulfate, 0.04 g / L manganese sulfate, 14 g / L agar, and 1 g / L Tween 80. The pH value for culturing using the medium is 6.5, and the temperature for culturing using the medium is 37°C.

[0053] Single colonies were selected, and the genome of the strain was extracted. Gene amplification was performed using universal primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-GGTTACCTTGTTACGACTT-3'). The amplification conditions were: 94℃ pre-denaturation for 3 min, 94℃ denaturation for 30 s, 55℃ annealing for 30 s, 72℃ extension for 1 min, repeated 30 times, followed by a final extension at 72℃ for 5 min, and storage at 4℃. The PCR products were analyzed by 1% agarose gel electrophoresis and homology comparison with the NCBI GenBank database. The 16S rDNA sequence of this strain, SEQ ID NO.1, is shown below.

[0054] Based on morphological analysis and molecular identification, this strain is identified as Streptococcus thermophilus (Streptococcus thermophilus). 嗜热链球菌 Linzhi.ST-1537 was deposited at the China Center for Type Culture Collection on April 15, 2025, with accession number CCTCCNO:M 2025782.

[0055] The colony morphology of this bacterium is as follows: Figure 1 As shown, the colony texture of this bacterium is milky white, with a smooth, opaque surface and neat edges.

[0056] The performance evaluation of this bacterium is as follows: Figure 2 As shown, this strain has the characteristics of high acetaldehyde and diacetyl production, which can significantly enhance the fruity, creamy, milky and sour flavors of the product.

[0057] Example 2 A fermented flavor powder with plateau characteristics is obtained by fermenting raw materials comprising the following components: 900g raw milk, 60g white sugar, 40g water, and 0.06g starter culture, wherein the starter culture is Lactobacillus delbrueckii subsp. lactis LBVⅢ (CCTCC NO: M 2023396) and Streptococcus thermophilus Linzhi.ST-1537 (CCTCC NO: M 2025782) in a 1:1 mass ratio. Specifically, the flavor powder is obtained by a preparation method comprising the following steps: (1) Preparation of fermented milk: Add 60g of white sugar and 40g of water to 900g of raw milk by mass, mix them well, sterilize them at 90℃ for 10min, and when they are cooled to 42℃, add 0.06g of starter culture, ferment at 42℃ for 10h, and the fermentation is terminated at an acidity of 120°T to obtain fermented milk.

[0058] (2) Demulsification: The fermented milk obtained in step (1) is demulsified by pouring it into a container and letting it stand at 15°C for 4 hours to obtain the demulsified fermented milk.

[0059] (3) Post-maturation: The fermented milk obtained in step (2) after demulsification is transferred to a cold storage and allowed to mature for 8 hours at a temperature of 4°C to obtain the fermented milk after maturation.

[0060] (4) Membrane separation: Using a 0.01 μm ultrafiltration membrane, under the conditions of 0.1 MPa pressure and 4℃ temperature, the fermented milk obtained in step (3) after ripening is circulated and filtered until the volume is reduced by 50% to obtain the filtered fermented milk.

[0061] (5) Drying: The filtered fermented milk obtained in step (4) is dried using a low-temperature drying device at a temperature of 35°C to obtain flavor powder.

[0062] Example 3 The difference from Example 2 is that, by weight, the flavor powder is obtained by fermentation of raw materials comprising the following components: 850g raw milk, 100g white sugar, 50g water and 0.08g starter culture, wherein the starter culture is Lactobacillus delbrueckii subsp. lactis Dangxiong LB VⅢ (CCTCC NO:M 2023396) and Streptococcus thermophilus Linzhi.ST-1537 (CCTCC NO:M 2025782) in a 1:1 weight ratio.

[0063] Example 4 The difference from Example 2 is that a 0.1 μm ultrafiltration membrane was used, and the filter was circulated at a pressure of 0.1 MPa and a temperature of 6 °C until the volume was reduced by 50%.

[0064] Example 5 The difference from Example 2 is that the filtered fermented milk obtained in step (4) is dried using a low-temperature drying device at a temperature of 50°C to obtain flavor powder.

[0065] Example 6 The difference from Example 2 is that the starter is Lactobacillus delbrueckii subsp. Dangxiong LB VⅢ (preservation number CCTCCNO:M 2023396).

[0066] Example 7 The difference from Example 2 is that the fermentation agent is Streptococcus thermophilus Linzhi.ST-1537 (preservation number CCTCC NO:M 2025782).

[0067] Example 8 The difference from Example 2 is that the starter culture is Lactobacillus delbrueckii subsp. lactis LBVⅢ (accession number CCTCCNO:M 2023396) and Streptococcus thermophilus Linzhi.ST-1537 (accession number CCTCCNO:M 2025782) in a mass ratio of 2:3.

[0068] Example 9 (1) Preparation of fermented milk: By mass, add 80g of white sugar and 45g of water to 900g of reconstituted milk with a milk powder content of 10g / mL. After mixing, sterilize at 90℃ for 10min. When it cools to 42℃, add 0.07g of starter culture and ferment at 39℃ for 11h. The fermentation is terminated at an acidity of 110°T to obtain fermented milk. The starter culture is Lactobacillus delbrueckii subsp. lactis Dangxiong LB VⅢ (CCTCC NO: M2023396) and Streptococcus thermophilus Linzhi.ST-1537 (CCTCC NO: M 2025782) in a mass ratio of 1:1.

[0069] (2) Demulsification: The fermented milk obtained in step (1) is poured into a container to demulsify, and then left to stand for 2 hours at a temperature of 20°C to obtain the demulsified fermented milk.

[0070] (3) Post-maturation: The fermented milk obtained in step (2) after demulsification is transferred to a cold storage and allowed to mature for 4 hours at a temperature of 2℃ to obtain the fermented milk after maturation.

[0071] (4) Membrane separation: Using a 0.05 μm ultrafiltration membrane, the fermented milk obtained in step (3) after ripening was circulated and filtered under the conditions of 0.05 MPa pressure and 2℃ temperature until the volume was reduced by 45% to obtain the filtered fermented milk.

[0072] (5) Drying: The filtered fermented milk obtained in step (4) is dried using a low-temperature drying device at a temperature of 30°C to obtain flavor powder.

[0073] Example 10 (1) Preparation of fermented milk: By mass, add 80g of white sugar and 45g of water to 900g of reconstituted milk with a milk powder content of 20g / mL. After mixing, sterilize at 90℃ for 10min. When it cools to 42℃, add 0.07g of starter culture and ferment at 45℃ for 12h. The fermentation is terminated at an acidity of 130°T to obtain fermented milk. The starter culture is Lactobacillus delbrueckii subsp. lactis Dangxiong LB VⅢ (CCTCC NO: M 2023396) and Streptococcus thermophilus Linzhi.ST-1537 (CCTCC NO: M 2025782) in a mass ratio of 1:1.

[0074] (2) Demulsification: The fermented milk obtained in step (1) is poured into a container to demulsify, and then left to stand for 5 hours at a temperature of 25°C to obtain the demulsified fermented milk.

[0075] (3) Post-maturation: The fermented milk obtained in step (2) after demulsification is transferred to a cold storage and post-maturated for 6 hours at a temperature of 8°C to obtain the post-maturated fermented milk.

[0076] (4) Membrane separation: Using a 0.05 μm ultrafiltration membrane, the fermented milk obtained in step (3) after ripening is circulated and filtered under the conditions of 0.2 MPa pressure and 6℃ until the volume is reduced by 55% to obtain the filtered fermented milk.

[0077] (5) Drying: The filtered fermented milk obtained in step (4) is dried using a low-temperature drying device at a temperature of 40°C to obtain flavor powder.

[0078] Comparative Example 1 The difference from Example 2 is that membrane separation technology is not used in step (4), and the supernatant is removed by centrifugation at 3000 r / min for 10 min.

[0079] Comparative Example 2 The difference from Example 2 is that spray drying is used in step (5), with an inlet air temperature of 130°C and an outlet air temperature of 70°C.

[0080] Comparative Example 3 The difference from Example 2 is that a commercially available sample (Chuanxiu food-grade yogurt starter) was used as the starter.

[0081] Comparison between comparative examples and embodiments The protein content, lactose content, total lactic acid bacteria count, and wettability of the flavor powders obtained in Examples 2-10 and Comparative Examples 1-3 were determined, as shown in Table 2.

[0082] *The total number of lactic acid bacteria in Table 2 is the sum of the number of Lactobacillus delbrueckii subsp. lactis Dangxiong LB VⅢ (accession number CCTCC NO: M 2023396) and Streptococcus thermophilus Linzhi.ST-1537 (accession number CCTCC NO: M 2025782).

[0083] The detailed measurement methods for each parameter in Table 2 are as follows: 1. Protein content determination Proteins shall be processed in accordance with GB 5009.5.

[0084] 2. Lactose content determination Lactose shall be handled in accordance with the provisions of GB 5413.5-2010.

[0085] 3. Determination of lactic acid bacteria content The total number of lactic acid bacteria shall be in accordance with the provisions of GB 4789.35.

[0086] 4. Wetting and sinking properties Prepare a 100 mL beaker, add 5 g of flavor powder sample to 50 mL of distilled water at 25 °C, and measure the time required for complete wetting without any stirring.

[0087] As shown in Table 2, the flavor powders prepared in Examples 2-10 contain 40-55 g / 100 g of protein, 0.01-0.02 g / 100 g of lactose, and a total lactic acid bacteria count of 1.2 × 10⁻⁶. 8 -5×10 9 The time required for 5g of the flavor powder to be completely wetted is 13-21 seconds (CFU / g).

[0088] Comparing the results of Comparative Example 1 with those of Examples 2-10, it was found that the lactose content in 100g of the flavor powder of Comparative Example 1 was 9g, which was much higher than the lactose content in the flavor powder of Examples 2-10. This demonstrates that using the membrane separation technology to treat fermented milk can effectively remove lactose from the flavor powder and enrich the protein. Comparing the results of Comparative Example 2 with those of Examples 2-10, it was found that the total number of lactic acid bacteria in the flavor powder of Comparative Example 2 was 3×10⁻⁶. 5 The CFU / g count was low, and it took 29 seconds for 5g of flavor powder from Comparative Example 2 to be completely wetted, indicating poor solubility. This suggests that low-temperature spray drying of fermented milk helps increase the total lactic acid bacteria count in the flavor powder, further improving its live bacteria content. Comparing the results of Comparative Example 3 with Examples 2-10, it was found that the flavor powder obtained using a commercially available sample (Chuanxiu food-grade yogurt starter powder) as the starter in Comparative Example 4 had a total lactic acid bacteria count of 4 × 10⁻⁶. 7The CFU / g is far lower than the total lactic acid bacteria count in the flavor powders of Examples 2-10. Therefore, the flavor powders described in Examples 2-10 of this invention are superior to commercially available samples (Chuanxiu food-grade yogurt starter powder). The flavor powders prepared using commercially available samples have a low total lactic acid bacteria count and poor solubility. Furthermore, it can be seen that the method described in Example 2 is the optimal combination, which not only maximizes the retention of protein and lactic acid bacteria but also removes excess lactose from the fermented milk, resulting in good solubility.

[0089] Application Example 1 Using the starter culture described in Example 2; using *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VⅢ (CCTCC NO: M 2023396) as the starter culture; using *Streptococcus thermophilus* Linzhi.ST-1537 (CCTCC NO: M2025782) as the starter culture; and using a commercially available sample (Chuanxiu food-grade yogurt starter culture powder) as the starter culture, four types of yogurt were prepared, and the performance of the four types of yogurt was evaluated. The specific yogurt preparation method is as follows: Dissolve milk powder in water to prepare 12 g / 100 mL reconstituted milk. Add 6 g / 100 mL of white sugar to the reconstituted milk, mix well, and boil to sterilize for 10 minutes. Then, cool it to 42°C and add the above-mentioned starter culture at an inoculation rate of 0.1 g / 100 mL. Ferment at a constant temperature of 42°C. After it solidifies, allow it to ripen at 4°C for 24 hours to obtain yogurt.

[0090] The acetaldehyde content, diacetyl content, water-holding capacity, and texture of the four types of yogurt prepared were determined, and sensory evaluations were performed. The results are as follows: Figure 2 As shown. The specific measurement method is as follows: 1. Acetaldehyde content determination The determination was performed using iodine titration. 2.0 mL of 1% NaHSO3 solution was accurately measured into a 250 mL Erlenmeyer flask with a stopper. 10 mL of the treated sample supernatant was added, and the solution was shaken well. After standing at room temperature for 1 hour, 1 mL of 1% starch solution was added. Then, 0.10 mol / L iodine standard solution was used to titrate to near the endpoint, followed by titration with 0.01 mol / L iodine standard solution to the endpoint (a pale blue-purple color that did not fade within 30 seconds). The volume of iodine standard solution consumed was not counted. Next, 20 mL of 1 mol / L NaHCO3 was added to the above solution, and the mixture was shaken until the blue color disappeared. Titration with 0.01 mol / L iodine standard solution was then used to the endpoint. The volume of iodine standard solution consumed in this titration was recorded, and a blank test was performed simultaneously.

[0091] Calculation formula: Acetaldehyde content (mg / L) = (V1 - V2) × C × 22.0 × 1000 / 10 V1—Volume of I2 standard solution consumed in sample titration (mL); V2—Volume of I2 standard solution consumed in blank titration (mL); C—Concentration of iodine standard solution (mol / L); 22.0—Molar mass of acetaldehyde (g / mol); 10—Acetaldehyde sample weight (mL).

[0092] 2. Determination of diacetyl content The diacetyl concentration was determined using the o-phenylenediamine colorimetric method. The sample was diluted with 16% trichloroacetic acid solution to an appropriate factor, and the absorbance was measured according to the o-phenylenediamine colorimetric method. Then, the diacetyl concentration (mg / L) in the sample could be obtained from the diacetyl standard curve.

[0093] 3. Water Holding Capacity (WHC) Measurement Weigh a certain mass (W0) of sample into a centrifuge tube, place it in a centrifuge, centrifuge at 3000 r / min for 20 min, remove the centrifuge tube, let it stand for 10 min, remove the supernatant, and determine the mass W of the residual substance in the centrifuge tube. The specific formula is as follows: WHC = W / W0 × 100% 4. Texture determination The textural properties of the samples were determined using a TA-XT Plus texture analyzer with a 3.5 cm diameter A / BE disc probe. Measurement conditions: trigger force 5 g, pre-measurement velocity 1.0 mm / s, measurement velocity 1.0 mm / s, post-measurement velocity 10.0 mm / s, and probe insertion distance 30 mm.

[0094] 5. Sensory evaluation The sensory evaluation panel, composed of 12 people with food evaluation experience, evaluated the appearance, smell, taste, texture, and likability of the samples. Each item was scored out of 20 points, and the sum of the scores for each item was the total sensory evaluation score, with a maximum score of 100 points.

[0095] according to Figure 2The results showed that the yogurt prepared with the starter culture described in Example 2 had an acetyl content of 22 mg / L, a diacetyl content of 26 mg / L, a water-holding capacity of 94%, a texture score of 90, and a sensory evaluation score of 90. The yogurt prepared with *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VⅢ (CCTCC NO: M 2023396) as the starter culture had an acetyl content of 7 mg / L, a diacetyl content of 3 mg / L, a water-holding capacity of 80%, a texture score of 77, and a sensory evaluation score of 87. The yogurt prepared with *Streptococcus thermophilus* Linzhi.ST-1537 (CCTCC NO: M... Yogurt prepared using 2025782 as a starter had an acetyl content of 11 mg / L, a diacetyl content of 5 mg / L, a water-holding capacity of 85%, a texture score of 75, and a sensory evaluation score of 85. Yogurt prepared using a commercially available sample (Chuanxiu food-grade yogurt starter) as a starter had an acetyl content of 7 mg / L, a diacetyl content of 1 mg / L, a water-holding capacity of 75%, a texture score of 65, and a sensory evaluation score of 77.

[0096] Based on the above results, it is evident that *Streptococcus thermophilus* Linzhi.ST-1537 possesses the characteristic of high acetaldehyde and diacetyl production, which can significantly improve the water-holding capacity and texture of the product. Furthermore, the yogurt prepared using the starter culture described in Example 2 exhibits superior acetaldehyde content, diacetyl content, water-holding capacity, texture, and sensory properties compared to yogurts prepared using *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VⅢ (CCTCC NO: M 2023396), *Streptococcus thermophilus* Linzhi.ST-1537 (CCTCC NO: M 2025782), and a commercially available sample (Chuanxiu food-grade yogurt starter culture powder), respectively.

[0097] Application Example 2 Bread was prepared using the plateau-characteristic fermented flavor powder obtained in Example 2 and milk powder, respectively. The specific preparation methods are as follows: Weigh out 15g softened butter, 10g egg liquid, 9g powdered sugar, 0.2g salt, and 15g flavor powder, and mix well to make the filling. Take 50g of dough, wrap it around 25g of filling, and proof it in a proofing box for 1 hour. Place the proofed dough in a baking box at 180℃ and bake for 16 minutes using both top and bottom heat to obtain the flavor powder bread.

[0098] By replacing the flavor powder in the above preparation method with an equal amount of milk powder, and keeping all other conditions the same, bread made with milk powder was obtained.

[0099] The bread obtained by the above method was subjected to sensory evaluation, and the specific sensory evaluation method is as follows: The sensory evaluation panel, composed of 25 people with food evaluation experience, evaluated the appearance, smell, taste, texture, and likability of the samples. Each item was scored out of 20 points, and the sum of the scores for each item was the total sensory evaluation score, with a maximum score of 100 points.

[0100] In Example 2, the appearance of the bread made with milk powder and the bread made with flavoring powder are described, including their partial appearance, overall appearance, and fillings. Figure 3A , Figure 3B and Figure 3C As shown.

[0101] The results showed that the bread in the milk powder group was too salty and bland. The bread in the flavored powder group had a significantly improved flavor, with a sweet and sour taste, similar to cheese.

[0102] Application Example 3 Tea drinks were prepared using the plateau-characteristic fermented flavor powder obtained in Example 2 and milk powder, respectively. The specific preparation methods are as follows.

[0103] ① Milk foam: Take 100g of flavor powder, 100g of ice water and 100g of fresh milk, beat them for 2-3 minutes to get milk foam, pour out the milk foam and set aside; ② Take 200mL of iced jasmine tea, 250g of ice cubes, 100g of dragon fruit, 30g of strawberry jam and 20mL of sugar, and blend them into a slush. ③ Pour 100mL of the milk foam obtained in step ① into the smoothie obtained in step ②, add an appropriate amount of dragon fruit as a garnish, and you will get the flavored powder tea drink.

[0104] By replacing the flavor powder in the above preparation method with an equal amount of milk powder, and keeping all other conditions the same, a milk powder-based tea beverage was obtained.

[0105] Sensory evaluation was performed on the milk foam and tea beverage prepared by the above method, and the sensory evaluation method was the same as that in Application Example 2.

[0106] The milk foam and tea drinks prepared using the flavor powder group and milk powder group in Example 3, such as Figure 4A and Figure 4B As shown.

[0107] The results showed that the milk foam prepared by the milk powder group had strong fluidity and a heavy powdery texture, while the milk foam prepared by the flavor powder group had weak fluidity and a more substantial texture. The tea drinks prepared by the milk powder group had weaker layers and poorer taste, while the tea drinks prepared by the flavor powder group had distinct layers, more beautiful color, better compatibility with other components, rich taste, and good palatability.

[0108] Application Example 4 Cat food was prepared using the plateau-characteristic fermented flavor powder obtained in Example 2 and milk powder, respectively. The specific preparation methods are as follows.

[0109] Based on the weight of the cat food, 3% of the flavor powder was mixed with commercially available cat food (Kuanfu Baked Cat Food) to obtain the flavor powder group cat food.

[0110] By replacing the flavor powder with milk powder in the above method, and keeping other conditions the same, we can obtain the milk powder group of cat food.

[0111] The palatability of the cat food prepared by the above method was analyzed, the feed intake rate was measured, and the physical condition of the cats after feeding was monitored, as shown in Table 3.

[0112] The specific performance testing methods are as follows in Table 3: Twelve healthy adult cats were selected and randomly divided into two groups of six cats each, based on the principles of similar genetic lineage, age, and weight, and an equal number of males and females. The cats were housed individually in pet cat cages (3 m × 1 m × 2 m). Before the experiment, the cats were vaccinated and dewormed, and given free access to water. The cat cages were cleaned daily to maintain cleanliness.

[0113] Palatability was studied using a single-feeder test. Cats in each group were fed either milk powder or flavored powder cat food. Each cat was given 100 g of cat food daily, and the amount of uneaten food was measured within 6 hours. The test period was 5 days. The cats' feed intake rate was calculated using the following formula: Feed intake rate (%) = (Feed amount - Leftover feed) / Feed amount × 100% Feed intake reflects a cat's palatability to different cat foods.

[0114] As shown in Table 3, the feed intake rate of cats fed with milk powder was 55%, while that of cats fed with flavored powder was 92%. All six cats in the milk powder group experienced varying degrees of vomiting and diarrhea, while none of the six cats in the flavored powder group exhibited these symptoms. Based on the results in Table 3, it was found that cat food prepared using flavored powder has better palatability. The flavored powder formula is clean, nutritionally rich, and has a superior flavor, making it more suitable for feeding dogs and cats.

[0115] The above embodiments are only for further explanation and understanding of the technical solution of the present invention, and are not intended to limit the present invention. Any improvements made by those skilled in the art on this basis that do not highlight substantive features or make significant progress should fall within the protection scope of the present invention.

Claims

1. A thermophilic streptococcus, characterized in that, The thermophilic streptococcus is: thermophilic streptococcus ( Streptococcus thermophilus Linzhi.ST-1537, accession number CCTCC NO:M 2025782.

2. A fermented flavor powder with plateau characteristics, characterized in that, The flavor powder is obtained by fermentation of raw materials comprising the following components: 850-900 parts raw milk, 60-100 parts white sugar, 40-50 parts water and 0.06-0.08 parts starter culture, wherein the starter culture is Streptococcus thermophilus Linzhi.ST-1537 and / or Lactobacillus delbrueckii subsp. Dangxiong LB VⅢ as described in claim 1.

3. The plateau-characteristic fermented flavor powder according to claim 2, characterized in that, The flavor powder is obtained by fermenting a raw material comprising the following components: 870-900 parts raw milk, and / or 60-80 parts white sugar, and / or 40-45 parts water, and / or 0.06-0.07 parts starter culture. Preferably, the flavor powder is obtained by fermentation of a raw material comprising the following components, by weight: 900 parts raw milk, and / or 60-65 parts white sugar, and / or 40-42 parts water, and / or 0.06 parts starter culture.

4. The plateau-characteristic fermented flavor powder according to claim 2 or 3, characterized in that, The fermentation agent is a mixture of Streptococcus thermophilus Linzhi.ST-1537 and / or Lactobacillus delbrueckii subsp. Dangxiong LB VⅢ; wherein the mass ratio of Streptococcus thermophilus Linzhi.ST-1537 to Lactobacillus delbrueckii subsp. Dangxiong LB VⅢ is 1-3:1-3; Preferably, the mass ratio of the thermophilic streptococcus Linzhi.ST-1537 to the lactobacillus subsp. Danxiong LB VⅢ is 1-2:1-3; More preferably, the mass ratio of the thermophilic streptococcus Linzhi.ST-1537 to the lactobacillus subsp. Dangxiong LB VⅢ is 1:

1.

5. The plateau-characteristic fermented flavor powder according to any one of claims 2-4, characterized in that, The raw milk includes raw cow's milk and / or reconstituted milk with a concentration of 10-20 g / mL obtained by dissolving milk powder in water; Preferably, the raw milk is raw cow's milk; and / or, the reconstituted milk concentration is 15-20 g / mL; More preferably, the concentration of the reconstituted milk is 18-20 g / mL.

6. The plateau-characteristic fermented flavor powder according to any one of claims 2-5, wherein, The flavor powder is obtained by fermenting, demulsifying, ripening, filtering and drying the raw materials.

7. The plateau-characteristic fermented flavor powder according to any one of claims 2-6, wherein, The flavor powder contains 40-55g of protein per 100g; and / or, the flavor powder contains 0.01-0.02g of lactose per 100g; and / or, the flavor powder contains 1.2×10⁻⁶ total lactic acid bacteria. 8 -5×10 9 CFU / g; and / or, the time required for 5g of the flavor powder to be completely wetted is 13-21s.

8. A method for preparing the flavor powder according to any one of claims 2-7, characterized in that, Includes the following steps: (1) Add the white sugar to the raw milk and mix evenly, pasteurize it, add the fermenting agent to the pasteurized raw milk for fermentation, and after demulsification and post-ripening, obtain post-ripened fermented milk. (2) The fermented milk obtained in step (1) after ripening was filtered using a 0.01-0.1 μm ultrafiltration membrane to obtain the filtrate; (3) The filter material obtained in step (2) is dried to obtain flavor powder.

9. The method for preparing the flavor powder according to claim 8, wherein, In step (1), the fermentation temperature is 39-45℃; Preferably, the fermentation time is 10-12 hours; and / or, the fermentation termination acidity is 110-130°T.

10. The method for preparing the flavor powder according to claim 8 or 9, wherein, In step (1), the demulsification temperature is 15-25℃; Preferably, the demulsification and standing time is 2-5 hours; and / or, the ripening time is 4-8 hours; and the ripening temperature is 2-8°C.

11. The method for preparing the flavor powder according to any one of claims 8-10, wherein, In step (2), the fermented milk obtained in step (1) after ripening is filtered using a 0.01-0.05 μm ultrafiltration membrane; Preferably, a 0.01 μm ultrafiltration membrane is used to filter the fermented milk obtained in step (1) after ripening.

12. The method for preparing the flavor powder according to any one of claims 8-11, wherein, In step (2), the filtration pressure is 0.05-0.2 MPa; Preferably, the filtration temperature is 2-6°C; and / or, the filtration is terminated when the volume of the filtered material is reduced to 45-55%.

13. The method for preparing the flavor powder according to any one of claims 8-12, wherein, In step (3), the drying is low-temperature spray drying; Preferably, the drying temperature is 30-50℃; More preferably, the drying temperature is 35-50°C; More preferably, the drying temperature is 35-40°C.

14. A fermented flavor powder with plateau characteristics, characterized in that, The flavor powder is obtained by the preparation method according to any one of claims 8-13.

15. A type of bread, characterized in that, The bread is made from the plateau-characteristic fermented flavor powder according to any one of claims 2-7 or the plateau-characteristic fermented flavor powder prepared by the preparation method according to any one of claims 8-13 and bread ingredients.

16. The bread according to claim 15, wherein, The bread ingredients include one or more of butter, egg liquid, powdered sugar, and salt; Preferably, the flavor powder content in the bread is 1-12% by mass.

17. A beverage, characterized in that, The beverage is made from the plateau-characteristic fermented flavor powder according to any one of claims 2-7 or the plateau-characteristic fermented flavor powder prepared by the preparation method according to any one of claims 8-13 and beverage raw materials.

18. The beverage according to claim 17, wherein, The flavor powder content in the beverage is 0.1-5% by mass. Preferably, the beverage includes yogurt or tea; More preferably, the yogurt is made from the flavor powder, water, and milk; and / or, the tea is made from the flavor powder, water, milk, tea, dragon fruit, strawberry jam, and sugar.

19. A type of cat food, characterized in that, The cat food is prepared from raw materials including the plateau-characteristic fermented flavor powder according to any one of claims 2-7 or the plateau-characteristic fermented flavor powder prepared by the preparation method according to any one of claims 8-13.

20. The cat food according to claim 19, wherein, The flavor powder content in the cat food is 1-5% by weight.

21. The application of a plateau-characteristic fermented flavor powder according to any one of claims 2-7 or a plateau-characteristic fermented flavor powder prepared by the preparation method according to any one of claims 8-13 in the food field.

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