An additive-free natural fruit-flavored yogurt and a method for preparing the same

Abstract

The application belongs to the technical field of dairy product processing, and particularly relates to a natural fruit-flavor yogurt without additives and a preparation method thereof. The natural fruit-flavor yogurt comprises the following raw materials in terms of the total mass of the raw materials: 80-92% of raw milk, 5-9% of sugar, 0.01-0.03% of a ferment, and the rest of water to make up to 100%. The ferment is Dangxiong LB VIII bacterial agent of lactobacillus delbrueckii subsp. lactis. The yogurt formula of the application does not add any food additives, jam and fruit juice, and meets the consumption trend of 'natural, nutritious and healthy'. Moreover, the yogurt product prepared by the application contains flavor substance phenylacetaldehyde, which gives the yogurt a pleasant special fruit flavor and a unique natural tomato flavor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of dairy product processing, and particularly relates to a natural fruit-flavored yogurt without additives and a preparation method thereof. BACKGROUND

[0002] Nutrient-rich, sweet and sour yogurt is a healthy food for the old and young. People who have abdominal distension and diarrhea after drinking milk can perfectly avoid the problem of lactose intolerance by drinking yogurt. With the improvement of consumers' awareness of digestive health, the yogurt market continues to grow. Fruit-flavored yogurt is favored by consumers because of its unique flavor and good taste.

[0003] Chinese patent CN103349073B discloses a probiotic fruit juice yogurt, which comprises the following raw materials by weight: raw milk 800-1000 parts, stabilizer 2.0-3.0 parts, white sugar 70-90 parts, bacterial strain 2-4 parts, apple thick syrup 2.0-3.0 parts, and green apple essence 0.35-0.42 parts. The technical solution adds fruit juice thick syrup and essence in the secondary dosing process after yogurt fermentation, ensuring the flavor of the product.

[0004] Chinese patent CN106259892B discloses a normal-temperature drinking yogurt, which is made from the following raw materials in the following mass percentages: fresh milk 80-86%, white sugar 7-12%, whey protein powder 0.5-2%, pectin 0.4-0.7%, agar 0.04-0.25%, gellan gum 0-0.03%, food essence 0-0.05%, and the balance is water. In the scheme, the addition of an appropriate amount of essence highlights the mellow flavor of the yogurt.

[0005] At present, conventional yogurt in the prior art is endowed with fruit flavor by adding fruit jam, concentrated fruit juice or fruit-flavored essence. On the one hand, the use of fruit-flavored essence does not conform to the concept of natural and healthy products; on the other hand, the addition of fruit jam or concentrated fruit juice in yogurt leads to an increase in production cost; finally, especially the low pH of some fruit juices will increase the instability of the yogurt system, and the improper use of some fruit-flavored essence is more likely to produce irritating and unpleasant odors, resulting in poor taste of the yogurt. SUMMARY

[0006] The technical problem solved by the present application is that conventional yogurt in the prior art is endowed with fruit flavor by adding fruit jam, concentrated fruit juice or fruit-flavored essence. Concentrated fruit juice has a high cost, and the low pH of some fruit juices will negatively affect the stability of the yogurt system, and the use of fruit-flavored essence is more likely to produce irritating and unpleasant odors, resulting in poor taste of the yogurt.

[0007] In view of the above technical problems, the present application provides a natural fruit-flavored yogurt and a preparation method thereof. The natural fruit-flavored yogurt does not need to add any fruit jam, fruit juice or essence, and can be prepared by a simple formula and an innovative combination of production processes, so as to have a natural fruit flavor, a refreshing taste and a unique taste, and meet the consumption trend of "natural, nutritious and healthy".

[0008] Specifically, the present application provides the following technical solutions.

[0009] In a first aspect, the present application provides a natural fruit-flavored yogurt, comprising the following raw materials, based on the total mass of the raw materials: 80-92% of raw milk, 5-9% of sugar, 0.01-0.03% of a fermenting agent, and the rest is supplemented with water to 100%; wherein the fermenting agent is Dangxiong LB VIII of Lactobacillus delbrueckii subsp. lactis, and the Dangxiong LB VIII of Lactobacillus delbrueckii subsp. lactis is preserved in the China Center for Type Culture Collection (CCTCC) with a preservation number of CCTCC NO: M 2023396.

[0010] Preferably, the natural fruit-flavored yogurt comprises the following raw materials, based on the total mass of the raw materials: 85-90% of raw milk.

[0011] Preferably, the natural fruit-flavored yogurt comprises the following raw materials, based on the total mass of the raw materials: 6-9% of sugar.

[0012] Preferably, the natural fruit-flavored yogurt comprises the following raw materials, based on the total mass of the raw materials: 0.015-0.03% of the fermenting agent.

[0013] Preferably, the natural fruit-flavored yogurt comprises the following raw materials, based on the total mass of the raw materials: 0.015-0.025% of the fermenting agent.

[0014] Preferably, the raw milk comprises one or more than two of skimmed milk powder, whole milk powder, semi-skimmed milk powder, modified milk powder and fresh milk.

[0015] Preferably, the fresh milk comprises one or more than two of horse milk, donkey milk, camel milk, goat milk and cow milk.

[0016] More preferably, the raw milk is selected from cow milk.

[0017] Preferably, the sugar comprises one or more than two of white granulated sugar, fructose, maltose, xylose and arabinose.

[0018] In a second aspect, the present application provides a preparation method of a natural fruit-flavored yogurt, comprising the following preparation steps:

[0019] (1) mixing: sugar is added to raw milk, then water is added, and shear emulsification is performed;

[0020] (2) homogenization: the mixed material is subjected to homogenization treatment;

[0021] (3) sterilization;

[0022] (4) inoculation of starter culture: the sterilized material is inoculated with a starter culture;

[0023] (5) primary fermentation: primary fermentation is performed;

[0024] (6) secondary fermentation: secondary fermentation is performed;

[0025] (7) cold storage for maturation.

[0026] Preferably, the preparation method is selected from Method One or Method Two.

[0027] Method One includes the following preparation steps:

[0028] (1) mixing: sugar is added to raw milk, then water is added, and shear emulsification is performed;

[0029] (2) homogenization: the mixed material is subjected to homogenization treatment;

[0030] (3) sterilization;

[0031] (4) inoculation of starter culture: the sterilized material is inoculated with a starter culture, and the product is filled and sealed in a sterile environment;

[0032] (5) primary fermentation: primary fermentation is performed;

[0033] (6) secondary fermentation: secondary fermentation is performed;

[0034] (7) cold storage for maturation.

[0035] Method Two includes the following preparation steps:

[0036] (1) mixing: sugar is added to raw milk, then water is added, and shear emulsification is performed;

[0037] (2) homogenization: the mixed material is subjected to homogenization treatment;

[0038] (3) sterilization;

[0039] (4) inoculation of starter culture: the sterilized material is inoculated with a starter culture, and the product is filled and sealed in a sterile environment;

[0040] (5) primary fermentation: primary fermentation is performed;

[0041] (6) secondary fermentation: secondary fermentation is carried out; after the fermentation is terminated, the tank is inverted to break emulsion, and cooling is performed; the product is filled and sealed in a sterile environment;

[0042] (7) cold ripening.

[0043] Preferably, the shearing emulsification in step (1) is performed for 5-10 min at a rotation speed of 2500-4000 rpm.

[0044] Preferably, the homogenization in step (2) is performed at a temperature of 50-80 ℃.

[0045] Preferably, the homogenization is performed at a low pressure of 2-5 MPa and a high pressure of 10-50 MPa.

[0046] Preferably, the sterilization in step (3) is performed at a temperature of 90-100 ℃ for 200-400 s.

[0047] Preferably, the inoculation of the starter in step (4) is performed at a temperature of 25-35 ℃.

[0048] Preferably, the primary fermentation in step (5) is performed at a temperature of 29-35 ℃ for 4-6 h.

[0049] Preferably, the primary fermentation in step (5) is terminated at an acidity of 30-40 °T.

[0050] Preferably, the secondary fermentation in step (6) is performed at a temperature of 39-45 ℃ for 8-13 h.

[0051] Preferably, the secondary fermentation in step (6) is terminated at an acidity of 70-90 °T.

[0052] Preferably, in the second method, after the fermentation in step (6) is terminated, the tank is inverted to break emulsion, and cooling is performed to a temperature of 15-25 ℃, and the product is allowed to stand for 2-5 h.

[0053] Preferably, in the second method, the product is filled at a temperature of 15-25 ℃ in step (6).

[0054] Preferably, in the first method, the product is filled at a temperature of 25-35 ℃ in step (4).

[0055] Preferably, the cold ripening in step (7) is performed at a temperature of 2-8 ℃ for 4-8 h.

[0056] Preferably, a natural fruit-flavored yogurt is prepared by the above method for preparing a natural fruit-flavored yogurt.

[0057] Preferably, the natural fruit-flavor yogurt has a tomato flavor.

[0058] Preferably, the natural fruit-flavor yogurt has a fruit flavor of benzaldehyde.

[0059] Preferably, the relative proportion of benzaldehyde is 1% to 5%.

[0060] Advantages of the present application

[0061] (1) The present application uses Lactobacillus delbrueckii subsp. lactis Dangxiong LB VIII as a fermenting agent to obtain a fermented milk product with strong fruit aroma and good texture.

[0062] (2) The yogurt formula of the present application does not add any food additives, jam, and fruit juice, which meets the consumer trend of "natural, nutritious, and healthy".

[0063] (3) The preparation process of the present application is simple and feasible, and is suitable for industrial production.

[0064] (4) The yogurt product prepared by the present application has a unique natural tomato flavor.

[0065] (5) The yogurt product prepared by the present application contains flavor substance benzaldehyde, which is a fruit aroma substance and gives the yogurt a pleasant special fruit flavor.

[0066] (5) The product has the flavor and taste of fermented milk, and also contains natural fruit aroma, and the fruit aroma becomes stronger with the extension of fermentation time.

[0067] Strain preservation information

[0068] The strain Lactobacillus delbrueckii subsp. lactis Dangxiong LB VIII used in the present application was preserved in China Center for Type Culture Collection (CCTCC) on March 23, 2023, with the preservation number CCTCC NO: M 2023396, and the preservation address is Wuhan, China. Wuhan University, postal code: 430072; telephone: (027)-68754833. BRIEF DESCRIPTION OF DRAWINGS

[0069] Figure 1 The preparation process of the additive-free natural fruit-flavor yogurt described in the present application. DETAILED DESCRIPTION

[0070] As described above, the present application aims to provide a natural fruit-flavored yogurt without additives and a preparation method thereof.

[0071] A first object of the present application is to provide a natural fruit-flavored yogurt, comprising the following raw materials in total mass of the raw materials: raw milk 80% to 92%, sugar 5% to 9%, starter 0.01% to 0.03%, and the rest is made up to 100% with water; wherein the starter is Lactobacillus delbrueckii subsp. lactis Dangxiong LB VIII, and the Lactobacillus delbrueckii subsp. lactis Dangxiong LB VIII (CCTCC NO: M 2023396) is preserved in the China Center for Type Culture Collection (CCTCC).

[0072] The screening, identification method and identification results of Lactobacillus delbrueckii subsp. lactis Dangxiong LB VⅢ

[0073] 1) Strain enrichment: 5 g of milk sample made by a herdsman in Dangxiong County, Tibet (elevation 4350 m) was crushed and uniformly dispersed in 45 mL of sterile normal saline, 2 mL of the dispersion was taken and added to 20 mL of sterilized litmus milk medium, and placed in a 37℃ incubator for incubation. When the medium was acidified and coagulated and showed pink color, it was taken out.

[0074] 2) Culturing single colonies: the litmus milk medium bacterial solution was diluted to 10 -5 times, 100 μL was taken and spread on BL solid medium plates, and placed in a 37℃ incubator for incubation. When colonies were formed, the colonies on the BL plates were smooth and slightly convex, moist, with unsmooth edges, colorless to slightly white, 1-3 mm in diameter, and the back of the colony was light yellow.

[0075] 3) Screening acid-producing bacteria: the single colonies obtained by preliminary screening were streaked on BL solid medium plates containing 0.2% CaCO3, and cultured in a 37℃ incubator for 36 h. After the incubation was completed, it was observed whether transparent circles were generated around the colonies, and single colonies with transparent circle diameter of 3-3.5 cm were selected for further separation and purification.

[0076] 4) Gram stain preliminary identification: Gram stain was performed on the strains of step (3), if the bacterial cells were stained purple, they were Gram-positive bacteria, and were kept for further study, if they were stained red, the strains were Gram-negative bacteria and were directly eliminated. The identification results showed that the obtained strains were Gram-positive bacteria, non-motile, no spores, no flagella, no capsule, the bacterial cells were thin rods, single rods or chains, and the strain was the target strain.

[0077] 5) Strain identification

[0078] The isolated and purified strain was a Gram stain positive, H2O2 contact enzyme negative, acid-producing, and non-gas-producing strain. 16S rDNA gene sequencing was performed, and the obtained results were compared with the homology analysis in the NCBI GenBank database. The results showed that the strain was Lactobacillus delbrueckii subsp. lactis. The 16S rDNA gene sequence of the strain is shown as SEQ ID NO. 1:

[0079] The sequence of SEQ ID NO. 1 is as follows:

[0080] GATTTGTTGGACGCTAGCGGCGGATGGGTGAGTAACACGTGGGCA

[0081] ATCTGCCCTAAAGACTGGGATACCACTTGGAAACAGGTGCTAATACCG

[0082] GATAACACCATGAATCGCATGATTCAAGTTTGAAAGGCGGCGCAAGCT

[0083] GTCACTTTAGGATGAGCCCGCGGCGCATTAGCTAGTTGGTGGGGTAAA

[0084] GGCCTACCAAGGCAATGATGCGTAGCCGAGTTGAGAGACTGATCGGC

[0085] CACATTGGGACTGAGACACGGCCCAAACTCCTACGGGAGGCAGCAGT

[0086] AGGGAATCTTCCACAATGGACGCAAGTCTGATGGAGCAACGCCGCGT

[0087] GAGTGAAGAAGGTCTTCGGATCGTAAAGCTCTGTTGTTGGTGAAGAAG

[0088] GATAGAGGCAGTAACTGGTCTTTATTTGACGGTAATCAACCAGAAAGT

[0089] CCCGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAG

[0090] CGTTGTCCGGATTTATTGGGCGTAAAGCGAGCGCAGGCGGAATGATAA

[0091] GTCTGATGTGAAAGCCCACGGCTCAACCGTGGAACTGCATCGGAAACT

[0092] GTCATTCTTGAGTGCAGAAGAGGAGAGTGGAACTCCATGTGTAGCGGT

[0093] GGAATGCGTAGATATATGGAAGAACACCAGTGGCGAAGGCGGCTCTC

[0094] TGGTCTGCAACTGACGCTGAGGCTCGAAAGCATGGGTAGCGAACAGG

[0095] ATTAGATACCCTGGTAGTCCATGCCGTAAACGATGAGCGCTAGGTGTT

[0096] GGGGACTTTCCGGTCCTCAGTGCCGCAGCAAACGCATTAAGCGCTCCG

[0097] CCTGGGGAGTACGACCGCAAGGTTGAAACTCAAAGGAATTGACGGGG

[0098] GCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCAACGCGAA

[0099] AAACCTTACCAGGTCTTGACATCCTGCGCTACACCTAGAGATAGGTGG

[0100] TTCCCTTCGGGGACGCAAAGACAGGTGGTGCATGGCTGTCGTCAGCTC

[0101] GTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGTC

[0102] TTTAGTTGCCATCATTAAGTTGGGCACTCTAAAGAGACTGCCGGTGAC

[0103] AAACCGGAGGAAGGTGGGGATGACGTCAAGTCATCATGCCCCTTATG

[0104] ACCTGGGCTACACACGTGCTACAATGTGCAGTACAACGAGAAGCGAA

[0105] CCCGCGAGGGTAAGCGGATCTCTTAAAGCTGCTCTCAGATCGGACTGC

[0106] GGGCTGCAACTCGCCTGCACGAAACTGGAATCGCTAGTAATCTCGGAT

[0107] CACCACGCCGCGGTGAATACGTTCCCGCGCCTTGTACACACCGCCCGT

[0108] CACACCATGGAAGTCTGCAATGCCCAAAGTCGGTGAGATAACCTTTAT

[0109] AGGAGTCAGCCGCCTAA

[0110] The strain was named Lactobacillus delbrueckii subsp. lactis Dangxiong LB VⅢ and was deposited at the China Center for Type Culture Collection (CCTCC) on March 23, 2023, with accession number CCTCC NO:M2023396.

[0111] Fermentation agent: Lactobacillus delbrueckii subsp. lactis Dangxiong LB VⅢ (abbreviated as DB-8) inoculum (live count greater than 1×10⁻⁶) 10 Preparation of CFU / g):

[0112] (1) The *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VIII strain preserved in glycerol tubes was activated. For the first activation, 3% of the culture was inoculated into MRS broth and cultured at 37°C for 24 h. For the second activation, 2% of the culture was inoculated and cultured at 37°C for 12 h. The activated bacterial solution was then inoculated into 2 L of MRS broth at 10% of the culture and fermented at 37°C for 12 h. After fermentation, the bacterial solution was transferred to a sterile centrifuge bottle and centrifuged at 5000×g at 4°C for 10 min. The supernatant was discarded, and the bacterial cells were washed twice with sterile physiological saline to obtain *Lactobacillus delbrueckii* subsp. *Dangxiong* LB VIII bacterial sludge.

[0113] (2) The mass percentages of each component of the freeze-drying protectant are as follows: 10% skim milk powder, 6% maltodextrin, and 4% sucrose. Dissolve each protectant in 55% pure water, stir thoroughly, and sterilize in a 90℃ constant temperature water bath for 30 minutes for later use.

[0114] (3) Prepare a mixture of cleaned Lactobacillus delbrueckii subsp. lactis LB VⅢ bacterial sludge and freeze-drying protectant at a ratio of 1:3. Add the bacterial sludge to the sterilized freeze-drying protectant, mix thoroughly in a sterile freeze-drying bottle, and pre-freeze in a -30℃ freezer for 12 hours. Place the pre-frozen bacterial milk in a vacuum freeze dryer and freeze-dry for 48 hours to obtain Lactobacillus delbrueckii subsp. lactis LB VⅢ freeze-dried bacterial powder.

[0115] Another object of the present invention is to provide two methods for preparing naturally fruit-flavored yogurt, such as... Figure 1 As shown.

[0116] The first preparation method is a solidification process, which includes the following steps:

[0117] (1) Raw milk pretreatment: Standardize the raw milk that has passed inspection;

[0118] (2) Mixing: Add sugar to the standardized raw milk, dilute with water, and shear emulsifier for 5-10 minutes at a speed of 2500-4000 rpm.

[0119] (3) Homogenization: The mixed raw materials are homogenized. The homogenization conditions are: temperature of 50-80℃, low pressure of 2-5MPa and high pressure of 10-50MPa.

[0120] (4) Sterilization: Sterilize at a temperature of 90-100℃ for 200-400 seconds;

[0121] (5) Access to starter culture: reduce the temperature to 25-35℃, add Lactobacillus delbrueckii subsp. lactis Dangxiong LB VIII starter culture, stir well to disperse evenly;

[0122] (6) Canning: quantitatively fill and seal the product under sterile environment, the filling temperature is 25-35℃;

[0123] (7) First-stage fermentation: place the fermentation tank in the fermentation room, the fermentation room temperature is 29-35℃, incubate and ferment for 4-6h, the first-stage fermentation stops when the acidity is 30-40°T;

[0124] (8) Second-stage fermentation: after the first-stage fermentation, place the fermentation tank in the fermentation room, the fermentation room temperature is 39-45℃, incubate and ferment for 8-13h, the second-stage fermentation stops when the acidity is 70-90°T;

[0125] (9) Enter the cold storage: after the fermentation stops, transfer to the cold storage, and post-ripen for 4-8h at a temperature of 2-8℃ to obtain the finished product yogurt.

[0126] The second preparation method is a stirring type process, comprising the following steps:

[0127] (1) Raw milk pretreatment: standardize the raw milk that has passed the inspection;

[0128] (2) Mixing: add sugar to the standardized raw milk, use water to make up the volume, and use a shearing emulsifier to shear for 5-10min, the shearing speed is 2500-4000rpm;

[0129] (3) Homogenization: homogenize the mixed raw material, the homogenization conditions are: the temperature is 50-80℃, the low pressure during homogenization is 2-5MPa, and the high pressure is 10-50MPa;

[0130] (4) Sterilization: sterilize at a temperature of 90-100℃ for 200-400s;

[0131] (5) Access to starter culture: after sterilizing the material, pour it into the fermentation tank, reduce the temperature to 25-35℃, add Lactobacillus delbrueckii subsp. lactis Dangxiong LB VIII starter culture, and stir well to disperse evenly;

[0132] (6) First-stage fermentation: place the fermentation tank in the fermentation room, the fermentation room temperature is 29-35℃, incubate and ferment for 4-6h, the first-stage fermentation stops when the acidity is 30-40°T;

[0133] (7) Second-stage fermentation: after the first-stage fermentation, place the fermentation tank in the fermentation room, the fermentation room temperature is 39-45℃, incubate and ferment for 8-13h, the second-stage fermentation stops when the acidity is 70-90°T;

[0134] (8) demulsification: after the fermentation is terminated, demulsification is performed by pouring the fermented milk into another low-temperature tank, and the temperature is lowered to 15-25 DEG C and kept at this temperature for 2-5 hours; wherein, pouring refers to transferring the demulsified fermented milk into another low-temperature tank. The purpose of demulsification is to reduce the viscosity of the fermented milk, and only stirring is needed to make the texture smooth and delicate.

[0135] (9) bottling: after the fermentation is terminated, the product is quantitatively filled and sealed in a sterile environment, and the filling temperature is 15-25 DEG C;

[0136] (10) entering the refrigerator: after filling, it is transferred to the refrigerator, and after ripening for 4-8 hours at a temperature of 2-8 DEG C, the finished yogurt is obtained.

[0137] In some embodiments, the standardization treatment or pretreatment is to make the raw milk meet the national standard GB 19301-2010 Food Safety National Standard Raw Milk in terms of odor, texture, fat content and density, etc. After passing the inspection, the raw milk that has passed the inspection is subjected to milk purification, and the protein content is corrected to 2.8%-3.2% by using flash evaporation and other processes.

[0138] The fruit flavor of the present application can be described as tomato flavor, which is different from the flavor of conventional yogurt. The GC-MS flavor substance detection results show that all the yogurts fermented by Lactobacillus delbrueckii subsp. lactis DB-8 inoculum contain benzaldehyde, while the other control products do not contain benzaldehyde. Therefore, it is believed that the unique fruit flavor produced by the present application is derived from benzaldehyde.

[0139] The various reagents / instruments used in the examples and comparative examples of the present application are all conventional commercially available products, unless otherwise specified. The experimental materials and instruments used in the present application are shown in the following table:

[0140] Table 2 Experimental materials / instruments and manufacturers

[0141] Reagent / instrument Purity / model Production / sale manufacturer Raw cow milk Protein 3.0~3.2% Yichang Phoenix Mountain Dairy Farm White granulated sugar First-class medium particle (purity≥99.6%) Guangxi Feng Sugar Luocheng Co., Ltd. Fructose Purity≥99% Qingdao Haivesen Biotechnology Co., Ltd. Maltose Purity≥99% Baolingbao Biological Co., Ltd. Shearing machine BME100L Shanghai Wei Yu Mechanical and Electrical Co., Ltd. High-pressure homogenizer JZG-Q50-P70 Shanghai Jia Ge Light Industry Machinery and Equipment Co., Ltd. Mini sterilizer YC-02 Shanghai Yacheng Instrument and Equipment Co., Ltd. Packaging sealing machine QZD-95 Wenzhou Zhuoyue Mechanical and Electrical Co., Ltd.

[0142] In order to better understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with specific examples.

[0143] Example 1

[0144] An additive-free natural fruit-flavored yogurt, comprising the following raw materials in terms of total mass of the raw materials: raw cow milk 85%, white granulated sugar 8%, Lactobacillus delbrueckii subsp. lactis DB-8 inoculum 200 g / T (200 g of DB-8 inoculum is added per 1 T of raw materials (the raw materials refer to raw cow milk, sugar, water and inoculum)), and the rest is made up to 100% with water (6.98%). The percentages of the components are the proportions of the mass of each component to the total mass of the raw materials. The total mass of the raw materials is 1 kg, and the mass of the Lactobacillus delbrueckii subsp. lactis DB-8 inoculum is 0.2 g (0.02%).

[0145] A method for preparing an additive-free natural fruit-flavored yogurt, comprising the following preparation steps:

[0146] (1) Raw cow milk pretreatment: standardizing the qualified raw cow milk;

[0147] (2) Mixing: adding white granulated sugar to the standardized raw cow milk, making up the volume with water, and shearing for 5 min using a shearing emulsifier at a shearing rotation speed of 3000 rpm;

[0148] (3) Homogenization: homogenizing the mixed raw materials under the following conditions: temperature 65℃, low pressure 5 MPa, and high pressure 15 MPa;

[0149] (4) Sterilization: sterilizing at a temperature of 95℃ for 300 s;

[0150] (5) Cooling and inoculation: cooling to 32℃, inoculating, and fully stirring to disperse uniformly at a stirring speed of 35 rpm for 15 min;

[0151] (6) Filling: filling and sealing the product under aseptic conditions at a filling temperature of 32℃;

[0152] (7) First-stage fermentation: placing the fermentation tank in a fermentation chamber at a temperature of 32℃, and incubating and fermenting for 6 h, with the first-stage fermentation being terminated at an acidity of 35°T;

[0153] (8) Second-stage fermentation: after the first-stage fermentation, placing the fermentation tank in a fermentation chamber at a temperature of 42℃, and incubating and fermenting for 11 h, with the second-stage fermentation being terminated at an acidity of 80°T;

[0154] (9) Entering the cold storage: after the fermentation is terminated, transferring to the cold storage, and post-ripening for 6 h at a temperature of 6℃ to obtain the finished yogurt.

[0155] Example 2

[0156] An additive-free natural fruit-flavored yogurt, comprising the following raw materials in total mass of the raw materials: 85% raw cow milk, 6.5% white granulated sugar, 1% fructose, 1% maltose, 200g / T of Lactobacillus delbrueckii subsp. lactis DB-8 inoculum, and the rest of water (6.48%) to make up to 100%, wherein the percentages of the components are the proportions of the mass of each component in the total mass of the raw materials. The total mass of the raw materials is 1 kg, and the mass of the Lactobacillus delbrueckii subsp. lactis DB-8 inoculum is 0.2 g (0.02%).

[0157] A method for preparing an additive-free natural fruit-flavored yogurt, comprising the following preparation steps:

[0158] (1) Raw cow milk pretreatment: standardizing the qualified raw cow milk;

[0159] (2) Mixing: adding white granulated sugar, fructose and maltose into the standardized raw cow milk, adding water to constant volume, and shearing for 5 min using a shearing emulsifier at a shearing rotation speed of 2500 rpm;

[0160] (3) Homogenization: homogenizing the mixed raw materials under the conditions of 60℃, low pressure 5 MPa and high pressure 15 MPa;

[0161] (4) Sterilization: sterilizing at a temperature of 95℃ for 300 s;

[0162] (5) Cooling and inoculation: cooling to 32℃, inoculating, fully stirring to disperse uniformly, stirring speed 35 rpm, stirring time 15 min;

[0163] (6) Filling: filling and sealing the product under aseptic conditions, filling temperature 32℃;

[0164] (7) First-stage fermentation: placing the fermentation tank in a fermentation room, fermentation room temperature 32℃, incubating and fermenting for 6 h, and the first-stage fermentation is terminated when the acidity is 35°T;

[0165] (8) Second-stage fermentation: after the first-stage fermentation, placing the fermentation tank in a fermentation room, fermentation room temperature 42℃, incubating and fermenting for 11 h, and the second-stage fermentation is terminated when the acidity is 80°T;

[0166] (9) Entering the refrigerator: after the fermentation is terminated, transferring to the refrigerator, and post-ripening at 6℃ for 6 h to obtain the finished yogurt.

[0167] Example 3

[0168] An additive-free natural fruit-flavored yogurt, comprising the following raw materials in total mass: raw cow milk 80%, white granulated sugar 5%, Lactobacillus delbrueckii subsp. lactis DB-8 inoculum 100 g / T, and the rest made up to 100% with water (14.99%). The percentage of each component is the proportion of the mass of each component to the total mass of the raw materials. The total mass of the raw materials is 1 kg, and the mass of the Lactobacillus delbrueckii subsp. lactis DB-8 inoculum is 0.1 g (0.01%).

[0169] A method for preparing an additive-free natural fruit-flavored yogurt, comprising the following preparation steps:

[0170] (1) Raw cow milk pretreatment: standardize the qualified raw cow milk;

[0171] (2) Mixing: add white granulated sugar to the standardized raw cow milk, make up the volume with water, and shear for 5 min at a shear speed of 3000 rpm using a shear emulsifier;

[0172] (3) Homogenization: homogenize the mixed raw materials under the following conditions: temperature 50℃, low pressure 2 MPa, and high pressure 10 MPa;

[0173] (4) Sterilization: sterilize at a temperature of 95℃ for 300 s;

[0174] (5) Cooling and inoculation: cool to 32℃, inoculate, and fully stir to disperse evenly at a stirring speed of 35 rpm for 15 min;

[0175] (6) Filling: quantitatively fill and seal the product under sterile conditions at a filling temperature of 32℃;

[0176] (7) First-stage fermentation: place the fermentation tank in a fermentation chamber at a temperature of 29℃, and incubate for 4 h. The first-stage fermentation is terminated when the acidity reaches 30°T;

[0177] (8) Second-stage fermentation: after the first-stage fermentation, place the fermentation tank in a fermentation chamber at a temperature of 39℃, and incubate for 13 h. The second-stage fermentation is terminated when the acidity reaches 70°T;

[0178] (9) Enter the cold storage: after the fermentation is terminated, transfer to the cold storage, and post-ripen for 6 h at a temperature of 4℃ to obtain the finished yogurt.

[0179] Example 4

[0180] An additive-free natural fruit-flavored yogurt, comprising the following raw materials in total mass: raw cow milk 90%, white granulated sugar 7.5%, Lactobacillus delbrueckii subsp. lactis DB-8 inoculum 300 g / T, and the rest made up to 100% with water (2.47%), wherein the percentages of the components are the proportions of the mass of each component to the total mass of the raw materials. The total mass of the raw materials is 1 kg, and the mass of the Lactobacillus delbrueckii subsp. lactis DB-8 inoculum is 0.3 g (0.03%).

[0181] A method for preparing an additive-free natural fruit-flavored yogurt, comprising the following preparation steps:

[0182] (1) Raw cow milk pretreatment: standardize the qualified raw cow milk;

[0183] (2) Mixing: add white granulated sugar to the standardized raw cow milk, make up the volume with water, and shear for 5 min at a shear speed of 3500 rpm using a shear emulsifier;

[0184] (3) Homogenization: homogenize the mixed raw materials under the following conditions: temperature 80℃, low pressure 4 MPa, and high pressure 50 MPa;

[0185] (4) Sterilization: sterilize at a temperature of 95℃ for 300 s;

[0186] (5) Cooling and inoculation: cool to 32℃, inoculate, and fully stir to disperse evenly at a stirring speed of 35 rpm for 15 min;

[0187] (6) Filling: quantitatively fill and seal the product under sterile conditions at a filling temperature of 32℃;

[0188] (7) First-stage fermentation: place the fermentation tank in a fermentation chamber at a temperature of 35℃, and incubate and ferment for 4 h, with the first-stage fermentation terminated at an acidity of 40°T;

[0189] (8) Second-stage fermentation: after the first-stage fermentation, place the fermentation tank in a fermentation chamber at a temperature of 45℃, and incubate and ferment for 8 h, with the second-stage fermentation terminated at an acidity of 90°T;

[0190] (9) Enter the cold storage: after the fermentation is terminated, transfer to the cold storage, and post-ripen for 7 h at a temperature of 6℃ to obtain the finished yogurt.

[0191] Example 5

[0192] An additive-free natural fruit-flavored yogurt, comprising the following raw materials in terms of total mass of the raw materials: raw cow milk 90%, white granulated sugar 7%, Lactobacillus delbrueckii subsp. lactis DB-8 inoculum 200 g / T, and the rest made up to 100% with water (2.98%). The percentages of the components are the proportions of the mass of each component to the total mass of the raw materials. The total weight of the raw materials is 1 kg, and the mass of the Lactobacillus delbrueckii subsp. lactis DB-8 inoculum is 0.2 g (0.02%).

[0193] A method for preparing an additive-free natural fruit-flavored yogurt, comprising the following preparation steps:

[0194] (1) Raw cow milk pretreatment: standardizing the qualified raw cow milk;

[0195] (2) Mixing: adding white granulated sugar to the standardized raw cow milk, making up the volume with water, and shearing for 5 min using a shearing emulsifier at a shearing rotation speed of 4000 rpm;

[0196] (3) Homogenization: homogenizing the mixed raw materials under the conditions of 65℃, low pressure 5 MPa, and high pressure 25 MPa;

[0197] (4) Sterilization: sterilizing at a temperature of 95℃ for 300 s;

[0198] (5) Cooling and inoculation: after sterilization, the material is pumped into a fermentation tank; cooling to 32℃, adding the inoculum, and fully stirring to disperse it uniformly at a stirring speed of 35 rpm for 15 min;

[0199] (6) First-stage fermentation: the temperature of the fermentation tank (in a sealed state) is 32℃, and the temperature is maintained for 6 h of fermentation, and the first-stage fermentation is terminated at an acidity of 35°T;

[0200] (7) Second-stage fermentation: after the first-stage fermentation, the temperature of the fermentation tank is set to 42℃, and the temperature is maintained for 11 h of fermentation, and the second-stage fermentation is terminated at an acidity of 80°T;

[0201] (8) Demulsification and cooling: after the fermentation is terminated, the tank is poured to demulsify, and the temperature is cooled to 25℃, and the temperature is maintained for 3 hours of standing;

[0202] (9) Filling: after the fermentation is terminated, the product is quantitatively filled and sealed in a sterile environment at a filling temperature of 20℃;

[0203] (10) Into the refrigerator: after filling, it is transferred to the refrigerator for 6 h of post-ripening at 6℃, and the finished yogurt is obtained.

[0204] Example 6

[0205] An additive-free natural fruit-flavored yogurt, comprising the following raw materials in terms of total mass of the raw materials: raw cow milk 90%, white granulated sugar 6%, fructose 1%, maltose 1%, Lactobacillus delbrueckii subsp. lactis DB-8 inoculum 200 g / T, and the rest made up to 100% with water (1.98%). The percentages of the components are the proportions of the mass of each component to the total mass of the raw materials. The total weight of the raw materials is 1 kg, and the mass of the Lactobacillus delbrueckii subsp. lactis DB-8 inoculum is 0.2 g (0.02%).

[0206] A method for preparing an additive-free natural fruit-flavored yogurt, comprising the following preparation steps:

[0207] (1) Raw cow milk pretreatment: standardizing the raw cow milk that has passed inspection;

[0208] (2) Mixing: adding white granulated sugar, fructose, and maltose to the standardized raw cow milk, making up the volume with water, and shearing for 5 min using a shearing emulsifier at a shearing rotation speed of 3000 rpm;

[0209] (3) Homogenization: homogenizing the mixed raw materials under the conditions of 65℃, low pressure 5 MPa, and high pressure 25 MPa;

[0210] (4) Sterilization: sterilizing at a temperature of 95℃ for 300 s;

[0211] (5) Cooling and inoculation: after sterilization, the material is pumped into a fermentation tank; the temperature is cooled to 32℃, the inoculum is added, and the inoculum is dispersed uniformly by thorough stirring at a stirring speed of 35 rpm for 15 min;

[0212] (6) First-stage fermentation: the temperature of the fermentation tank is set to 32℃, and the material is incubated for 6 h; the first-stage fermentation is terminated when the acidity reaches 35°T;

[0213] (7) Second-stage fermentation: after the first-stage fermentation, the temperature of the fermentation tank is set to 42℃, and the material is incubated for 11 h; the second-stage fermentation is terminated when the acidity reaches 80°T;

[0214] (8) Demulsification and cooling: after the fermentation is terminated, the material is demulsified by pouring out of the tank, and the temperature is cooled to 25℃, and the material is kept at this temperature for 3 h;

[0215] (9) Filling: after the fermentation is terminated, the product is filled and sealed under aseptic conditions; the filling temperature is 20℃;

[0216] (10) Storage in a refrigerator: after filling, the product is transferred to a refrigerator and is post-ripened at 6℃ for 6 h to obtain the finished yogurt.

[0217] Comparative Example 1

[0218] A yogurt, comprising the following raw materials in total mass: raw cow milk 85%, white granulated sugar 6.5%, yogurt starter (model Y0-C667-F, purchased from Hebei Yiran Biotechnology Co., Ltd.) 200 g / T, and the rest water (8.48%) to make up to 100%. The percentage of each component is the proportion of the mass of each component to the total mass of raw materials. The total weight of raw materials is 1 kg, and the mass of yogurt starter Y0-C667-F is 0.2 g (0.02%).

[0219] A method for preparing a yogurt, comprising the following preparation steps:

[0220] (1) Raw cow milk pretreatment: standardize the qualified raw cow milk;

[0221] (2) Mixing: add white granulated sugar to the standardized raw cow milk, add water to constant volume, and use a shear emulsifier to shear for 5 min at a shear rotation speed of 3500 rpm;

[0222] (3) Homogenization: homogenize the mixed raw materials under the conditions of 65℃, low pressure 5 MPa, and high pressure 15 MPa;

[0223] (4) Sterilization: sterilize at a temperature of 95℃ for 300 s;

[0224] (5) Cooling and inoculation: cool to 32℃, inoculate, and fully stir to disperse evenly at a stirring speed of 35 rpm for 15 min;

[0225] (6) Filling: quantitatively fill and seal the product under sterile conditions at a filling temperature of 32℃;

[0226] (7) First-stage fermentation: place the fermentation tank in a fermentation chamber at a temperature of 32℃, and incubate and ferment for 1.5 h. The first-stage fermentation is terminated when the acidity reaches 35°T;

[0227] (8) Second-stage fermentation: after the first-stage fermentation, place the fermentation tank in a fermentation chamber at a temperature of 42℃, and incubate and ferment for 3 h. The second-stage fermentation is terminated when the acidity reaches 80°T;

[0228] (9) Enter the cold storage: after the fermentation is terminated, transfer to the cold storage, and post-ripen at 6℃ for 6 h to obtain the finished yogurt.

[0229] Comparative Example 2

[0230] A yogurt, comprising the following raw materials in total mass: raw cow milk 85%, white granulated sugar 6.5%, yogurt starter (model Y0-C975-F, purchased from Hebei Yiran Biotechnology Co., Ltd.) 200 g / T, and the rest water (8.48%) to make up to 100%, the percentage of each component being the proportion of the mass of each component to the total mass of raw materials. The total weight of raw materials is 1 kg, and the mass of yogurt starter Y0-C975-F is 0.2 g (0.02%).

[0231] A method for preparing a yogurt, comprising the following preparation steps:

[0232] (1) raw cow milk pretreatment: standardizing the qualified raw cow milk;

[0233] (2) mixing: adding white granulated sugar to the standardized raw cow milk, using water to make up the volume, and shearing for 5 min using a shearing emulsifier at a shearing rotation speed of 3000 rpm;

[0234] (3) homogenization: homogenizing the mixed raw materials under the conditions of 65℃, low pressure 5 MPa, and high pressure 20 MPa;

[0235] (4) sterilization: sterilizing at a temperature of 95℃ for 300 s;

[0236] (5) cooling and inoculation: after sterilization, the material is pumped into a fermentation tank, cooled to 32℃, and inoculated with fermentation agent, stirred to disperse, at a stirring speed of 35 rpm for 15 min;

[0237] (6) bottling: under sterile conditions, the product is quantitatively filled and sealed, and the filling temperature is 32℃;

[0238] (7) first-stage fermentation: the fermentation tank is placed in a fermentation chamber with a temperature of 32℃, and incubated for 1.5 h, and the first-stage fermentation is terminated at an acidity of 35°T;

[0239] (8) second-stage fermentation: the fermentation tank is placed in a fermentation chamber with a temperature of 42℃, and incubated for 3.5 h, and the second-stage fermentation is terminated at an acidity of 80°T;

[0240] (9) entering the refrigerator: after fermentation, the product is incubated at 4℃ for 6 h to obtain the finished yogurt.

[0241] Comparative Example 3

[0242] A yogurt, comprising the following raw materials in total mass of the raw materials: 85% raw cow milk, 8% white granulated sugar, 200g / T of Lactobacillus delbrueckii subsp. lactis DB-8 inoculum, and the rest water (6.98%) to make up to 100%, wherein the percentage of each component is the proportion of the mass of each component in the total mass of the raw materials. The total weight of the raw materials is 1 kg, and the mass of the Lactobacillus delbrueckii subsp. lactis DB-8 inoculum is 0.2 g (0.02%).

[0243] A method for preparing a yogurt, comprising the following preparation steps:

[0244] (1) Raw cow milk pretreatment: standardizing the qualified raw cow milk;

[0245] (2) Mixing: adding white granulated sugar into the standardized raw cow milk, using water to make up the volume, and shearing for 5 min using a shearing emulsifier at a shearing rotation speed of 3000 rpm;

[0246] (3) Homogenization: homogenizing the mixed raw materials under the conditions of 65℃, low pressure 5 MPa, and high pressure 15 MPa;

[0247] (4) Sterilization: sterilizing at a temperature of 95℃ for 300 s;

[0248] (5) Cooling and inoculation: cooling to 32℃, inoculating, fully stirring to make it uniformly dispersed, stirring speed 35 rpm, stirring time 15 min;

[0249] (6) Filling: filling and sealing the product under aseptic conditions, filling temperature 32℃;

[0250] (7) First-stage fermentation: placing the fermentation tank in a fermentation room, fermentation room temperature 32℃, incubating and fermenting for 19 h, and the first-stage fermentation is terminated when the acidity is 80°T;

[0251] (8) Entering the cold storage: after the fermentation is terminated, transferring to the cold storage, and ripening at 6℃ for 6 h to obtain the finished product yogurt.

[0252] Comparative Example 4

[0253] A yogurt, comprising the following raw materials in total mass of the raw materials: 85% raw cow milk, 8% white granulated sugar, 200g / T of Lactobacillus delbrueckii subsp. lactis DB-8 inoculum, and the rest water (6.98%) to make up to 100%, wherein the percentage of each component is the proportion of the mass of each component in the total mass of the raw materials. The total weight of the raw materials is 1 kg, and the mass of the Lactobacillus delbrueckii subsp. lactis DB-8 inoculum is 0.2 g (0.02%).

[0254] A method for preparing a yogurt, comprising the following preparation steps:

[0255] (1) Raw milk pretreatment: The qualified raw milk was subjected to standardization treatment;

[0256] (2) Mixing: white granulated sugar was added into the standardized raw milk, and water was added to constant volume, and shearing emulsifier was used for shearing for 5 min at a shearing speed of 3200 rpm;

[0257] (3) Homogenization: the mixed raw materials were subjected to homogenization treatment, and the homogenization conditions were 65℃, low pressure 5 MPa and high pressure 15 MPa;

[0258] (4) Sterilization: sterilization was performed at a temperature of 95℃ for 300 s;

[0259] (5) Cooling and inoculation: cooling to 42℃, inoculation, and fully stirring to disperse uniformly, stirring speed 35 rpm, stirring time 15 min;

[0260] (6) Filling: the product was subjected to quantitative filling and sealing in a sterile environment, and the filling temperature was 42℃;

[0261] (7) First-stage fermentation: the fermentation tank was placed in a fermentation room, the fermentation room temperature was 42℃, and incubation fermentation was performed for 17 h, and the first-stage fermentation was terminated at an acidity of 80°T;

[0262] (8) Into the refrigerator: after fermentation was terminated, it was transferred to a refrigerator, and after-ripening was performed at 6℃ for 6 h to obtain the finished product yogurt.

[0263] Application Example 1

[0264] The yogurt products obtained in the above examples and comparative examples were subjected to product fruity aroma, taste and other index scoring. Ten people who had participated in sensory training and were related to dairy products were randomly selected as sensory evaluators, and the scoring standards were as follows.

[0265] Table 3 Scoring standards for yogurt products

[0266]

[0267] The above "fruity aroma" refers to the fruity aroma brought by benzene acetaldehyde, and more specifically to the tomato flavor.

[0268] The scoring values of the sensory evaluators were averaged, and the scores of each index were added to obtain the total score, and the higher the score, the higher the product satisfaction. The results are shown in Table 4.

[0269] Table 4 Scoring results of yogurt products obtained in examples and comparative examples

[0270] Yogurt product Fruit aroma / points Taste / points Total / points Example 1 10 9 19 Example 2 10 8 18 Example 3 9 7 16 Example 4 9 9 18 Example 5 8 8 16 Example 6 9 8 17 Comparative example 1 1 6 7 Comparative example 2 2 7 9 Comparative example 3 7 7 14 Comparative example 4 8 6 14

[0271] From the results of the above table, it can be seen that the yogurt prepared by using the formula and process combination provided by the present application has rich fruit aroma, unique taste and high satisfaction. Examples 1-4 are coagulation type processes, and examples 5-6 are stirring type processes. The yogurt obtained by the two processes can produce full fruit aroma and has good taste. Compared with examples 1-4, the comprehensive score of the yogurt obtained by comparative example 1 using other commercially available yogurt starter is much lower than that of examples 1-6. The comprehensive score of the yogurt obtained by comparative example 2 using other commercially available yogurt starter is also much lower than that of examples 1-6. The comprehensive score of the yogurt obtained by comparative example 3 which is fermented only once and uses the temperature of one-stage fermentation is much lower than that of examples 1-6. The comprehensive score of the yogurt obtained by comparative example 4 which is fermented only once and uses the temperature of two-stage fermentation is lower than that of examples 1-6. The above data show that only the yogurt formula and the corresponding preparation process defined in the present application can make the obtained yogurt have rich fruit aroma and good taste.

[0272] Application Example 2

[0273] The aroma components of the yogurt products prepared by the above example 1 and comparative example 1 were subjected to qualitative analysis by GC-MS (HP7890 / 5975C type GC-MS combined instrument, Agilent Technologies company), and the detection parameters are shown in the following table.

[0274] Table 5 GC-MS parameters for flavor detection of yogurt products

[0275]

[0276] The flavor components of the yogurt products of example 1 and comparative example 1 obtained by GC-MS qualitative analysis are shown in the following table.

[0277] Table 6 Main flavor components of the yogurt product obtained by example 1

[0278]

[0279]

[0280] Note: The example 1 of the present application is repeated for multiple experiments, and each experiment is sampled for GC-MS detection. The retention time of the flavor substances produced by each batch sample has slight differences, so the retention time here is a range value. The relative proportion is obtained by referring to the added internal standard.

[0281] Table 7 Main flavor components of the yogurt product obtained by comparative example 1

[0282] Sequence number Retention time (min) Relative proportion (%) Compound name Molecular formula 1 6.793～7.263 20.92～24.63 2,3-pentanedione [C5H8O2] 2 15.503～15.752 6.01～8.34 Nonanal [C9H 18 O]]> 3 16.531～17.942 16.31～18.78 Acetic acid [C2H4O2 <!-- 14 -->]]> 4 18.314～19.839 1.32～1.39 n-octanol [C8H 18 O]]> 5 19.357～20.894 7.45--8.69 2-undecanone C 11 H 22 O]]> 6 20.913～21.492 45.31～49.78 Butyric acid [C4H8O2] 7 22.013～22.345 2.41～2.69 Furfuryl alcohol [C5H6O2] 8 22.744～23.503 0.25～0.399 Nonanal [C9H 18 O]]> 9 23.734～24.181 0.94～1.21 Valeric acid [C5H 10 O2]]> 10 24.845～25.696 0.31～0.562 Phenyl ethyl acetate C 10 H 12 O2]]> 11 25.983～26.898 131.29～151.32 Caproic acid [C6H 12 O2]]> 12 29.844～30.895 35.24～38.19 Octanoic acid [C8H 16 O2]]>

[0283] Note: The present application will be repeated for a number of experiments of Comparative Example 1, and each experiment is sampled for GC-MS inspection. The retention time of the flavor substance produced by each batch sample is slightly different, so the retention time here is a range value. The relative proportion is obtained by referring to the added internal standard.

[0284] From the above table, it can be seen that Comparative Example 1 uses other commercially available yogurt starter, and the main flavor substance composition of the obtained yogurt product does not contain benzaldehyde, i.e. it cannot produce special fruit aroma benzaldehyde. The present application uses Lactobacillus delbrueckii subsp. lactis Dangxiong LB VIII as a starter, and the obtained yogurt product contains the special fruit aroma of benzaldehyde.

[0285] Although the specific embodiments of the present application have been described above, they are not intended to limit the scope of protection of the present application. Various modifications or variations made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the scope of protection of the present application.

Claims

1. A natural fruit-flavored yogurt, characterized in that, The natural fruit-flavored yogurt comprises, based on the total mass of the raw materials: 80-92% raw milk, 5-9% sugar, 0.01-0.03% starter culture, and the balance made up to 100% with water. The starter is Dangxiong LB VIII (Lactobacillus delbrueckii subsp. lactis) bacterial agent, Dangxiong LB VIII (Lactobacillus delbrueckii subsp. lactis) bacterial agent is preserved in China Center for Type Culture Collection (CCTCC) with a preservation number of CCTCC NO: M 2023396. Lactobacillus delbrueckii subsp. lactis Dangxiong LB VIII) has tomato flavor, and the natural fruit-flavored yogurt has fruit flavor of phenylacetaldehyde. The preparation method of the natural fruit-flavored yogurt comprises the following steps: (1) mixing: adding sugar into raw milk, then adding water, and shearing and emulsifying; (2) homogenizing: homogenizing the mixed material; (3) sterilizing; (4) inoculating the starter culture: inoculating the sterilized material with the starter culture; (5) first-stage fermentation: performing first-stage fermentation; the first-stage fermentation is performed at a temperature of 29-35°C for 4-6 hours; (6) second-stage fermentation: performing second-stage fermentation; the second-stage fermentation is performed at a temperature of 39-45°C for 8-13 hours; (7) cold storage for post-ripening.

2. The natural fruit-flavored yogurt according to claim 1, wherein, The raw milk comprises, based on the total mass of the raw materials: 85-90% raw milk; And / or, the sugar comprises 6-9%; And / or, the starter culture comprises 0.015-0.03%.

3. The natural fruit-flavored yogurt according to claim 1, wherein, The raw milk comprises one or more than two of skimmed milk powder, whole milk powder, prepared milk powder and fresh milk.

4. The natural fruit-flavored yogurt according to claim 2, wherein, The raw milk comprises one or more than two of skimmed milk powder, whole milk powder, prepared milk powder and fresh milk.

5. The natural fruit-flavored yogurt according to claim 3, wherein, The fresh milk comprises one or more than two of horse milk, donkey milk, camel milk, goat milk and cow milk.

6. The natural fruit-flavored yogurt of claim 1, wherein, The raw milk is selected from cow milk.

7. The natural fruit-flavored yogurt according to any one of claims 1-6, wherein, The sugar comprises one or more than two of white granulated sugar, fructose, maltose, xylose and arabinose.

8. A process for the preparation of a natural fruit-flavored yoghurt according to any one of claims 1 to 7, characterized in that, The preparation method comprises the following steps: (1) mixing: adding sugar into raw milk, then adding water, and shearing and emulsifying; (2) homogenizing: homogenizing the mixed material; (3) sterilizing; (4) inoculating the starter culture: inoculating the sterilized material with the starter culture; (5) first-stage fermentation: performing first-stage fermentation; the first-stage fermentation is performed at a temperature of 29-35°C for 4-6 hours; (6) second-stage fermentation: performing second-stage fermentation; the second-stage fermentation is performed at a temperature of 39-45°C for 8-13 hours; (7) cold storage for post-ripening.

9. The method of preparing natural fruit-flavored yogurt according to claim 8, wherein, The preparation method is selected from Method I or Method II; Method I comprises the following steps: (1) mixing: adding sugar into raw milk, then adding water, and shearing and emulsifying; (2) homogenizing: homogenizing the mixed material; (3) sterilizing; (4) inoculating the starter culture: inoculating the sterilized material with the starter culture, and filling and sealing the product in a sterile environment; (5) first-stage fermentation: performing first-stage fermentation; (6) second-stage fermentation: performing second-stage fermentation; (7) cold storage for post-ripening; Method II comprises the following steps: (1) mixing: adding sugar into raw milk, then adding water, and shearing and emulsifying; (2) homogenizing: homogenizing the mixed material; (3) sterilizing; (4) inoculating the starter culture: inoculating the sterilized material into a fermentation tank, and then inoculating the starter culture; (5) first-stage fermentation: performing first-stage fermentation; (6) Secondary fermentation: secondary fermentation is carried out; after the fermentation is terminated, the tank is poured and demulsification is carried out, and cooling is carried out; the product is filled and sealed in a sterile environment; (7) Cold storage ripening.

10. The method of preparing natural fruit-flavored yogurt according to claim 8, wherein, The shearing emulsification in step (1) is carried out for 5-10 min at a shearing speed of 2500-4000 rpm.

11. The method of preparing natural fruit-flavored yogurt according to claim 9, wherein, The shearing emulsification in step (1) is carried out for 5-10 min at a shearing speed of 2500-4000 rpm.

12. The method of preparing natural fruit-flavored yogurt according to claim 8, wherein, The homogenization in step (2) is carried out at a temperature of 50-80 ℃; And / or, the low pressure during homogenization is 2-5 MPa, and the high pressure is 10-50 MPa.

13. The method of preparing natural fruit-flavored yogurt according to claim 9, wherein, The homogenization in step (2) is carried out at a temperature of 50-80 ℃; And / or, the low pressure during homogenization is 2-5 MPa, and the high pressure is 10-50 MPa.

14. The method of preparing natural fruit-flavored yogurt according to claim 10, wherein, The homogenization in step (2) is carried out at a temperature of 50-80 ℃; And / or, the low pressure during homogenization is 2-5 MPa, and the high pressure is 10-50 MPa.

15. The method of preparing natural fruit-flavored yogurt according to claim 8, wherein, The sterilization in step (3) is carried out at a temperature of 90-100 ℃ for 200-400 s; And / or, the inoculation of the fermenting agent in step (4) is carried out at a temperature of 25-35 ℃.

16. The method of preparing natural fruit-flavored yogurt according to claim 9, wherein, The sterilization in step (3) is carried out at a temperature of 90-100 ℃ for 200-400 s; And / or, the inoculation of the fermenting agent in step (4) is carried out at a temperature of 25-35 ℃.

17. The method of preparing natural fruit-flavored yogurt according to claim 10, wherein, The sterilization in step (3) is carried out at a temperature of 90-100 ℃ for 200-400 s; And / or, the inoculation of the fermenting agent in step (4) is carried out at a temperature of 25-35 ℃.

18. The method of preparing natural fruit-flavored yogurt according to claim 12, wherein, The sterilization in step (3) is carried out at a temperature of 90-100 ℃ for 200-400 s; And / or, the inoculation of the fermenting agent in step (4) is carried out at a temperature of 25-35 ℃.

19. The method of preparing natural fruit-flavored yogurt according to claim 8, wherein, The sterilization in step (3) is carried out at a temperature of 90-100 ℃ for 200-400 s; 20. The method of preparing natural fruit-flavored yogurt according to claim 9, wherein, And / or, the inoculation of the fermenting agent in step (4) is carried out at a temperature of 25-35 ℃.

21. The method of preparing natural fruit-flavored yogurt according to claim 10, wherein, In step (5), the terminal acidity of the first-stage fermentation is 30-40 °T.

22. The method of preparing natural fruit-flavored yogurt according to claim 12, wherein, In step (5), the terminal acidity of the first-stage fermentation is 30-40 °T.

23. The method of preparing natural fruit-flavored yogurt according to claim 15, wherein, In step (5), the terminal acidity of the first-stage fermentation is 30-40 °T.

24. The method of preparing natural fruit-flavored yogurt according to claim 8, wherein, In step (5), the terminal acidity of the first-stage fermentation is 30-40 °T.

25. The method of preparing natural fruit-flavored yogurt according to claim 9, wherein, In step (5), the terminal acidity of the first-stage fermentation is 30-40 °T.

26. The method of preparing natural fruit-flavored yogurt according to claim 10, wherein, In step (6), the terminal acidity of the second-stage fermentation is 70-90 °T.

27. The method of preparing natural fruit-flavored yogurt according to claim 12, wherein, In step (6), the terminal acidity of the second-stage fermentation is 70-90 °T.

28. The method of preparing natural fruit-flavored yogurt according to claim 15, wherein, In step (6), the terminal acidity of the second-stage fermentation is 70-90 °T.

29. The method of preparing a natural fruit-flavored yogurt according to claim 19, wherein, In step (6), the terminal acidity of the second-stage fermentation is 70-90 °T.

30. The method of preparing natural fruit-flavored yogurt according to any one of claims 9, 11, 13, 16, 20 and 25, wherein, In step (6), the terminal acidity of the second-stage fermentation is 70-90 °T.

31. The method of preparing natural fruit-flavored yogurt according to any one of claims 9, 11, 13, 16, 20 and 25, wherein, In step (6), the terminal acidity of the second-stage fermentation is 70-90 °T.

32. The method of preparing a natural fruit-flavored yogurt according to claim 30, wherein, In step (6), the terminal acidity of the second-stage fermentation is 70-90 °T. In the second method, in step (6), after the fermentation is terminated, the tank is poured and demulsification is carried out, and cooling is carried out to 15-25 ℃, and the product is statically placed for 2-5 h. In the second method, in step (6), the temperature during filling is 15-25 ℃. In the second method, in step (6), the temperature during filling is 15-25 ℃.

33. The method of preparing natural fruit-flavored yogurt according to any one of claims 9, 11, 13, 16, 20 and 25, wherein, In the method, the temperature during the filling in step (4) is 25-35℃.

34. The method of preparing a natural fruit-flavored yogurt according to any one of claims 8-29, wherein, In step (7), the conditions for the cold storage and maturation are as follows: the temperature for the cold storage and maturation is 2-8℃, and the time for the cold storage and maturation is 4-8h.

35. The method of preparing a natural fruit-flavored yogurt according to claim 30, wherein, In step (7), the conditions for the cold storage and maturation are as follows: the temperature for the cold storage and maturation is 2-8℃, and the time for the cold storage and maturation is 4-8h.

36. The method of preparing a natural fruit-flavored yogurt according to claim 31, wherein, In step (7), the conditions for the cold storage and maturation are as follows: the temperature for the cold storage and maturation is 2-8℃, and the time for the cold storage and maturation is 4-8h.

37. A natural fruit-flavored yogurt, characterized in that, The natural fruit-flavored yogurt is prepared by the method for preparing the natural fruit-flavored yogurt according to any one of claims 8-36.

38. The natural fruit-flavored yogurt of any one of claims 1-7 or claim 37, wherein, The relative proportion of phenylacetaldehyde is 1%-5%.

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