Method for preparing yogurt and yogurt

Abstract

The application provides a yogurt preparation method and yogurt, wherein the yogurt preparation method comprises the following steps: adding lactase into cow milk, stirring uniformly, and then standing for enzymolysis; browning the enzymolyzed cow milk at 100-120 DEG C for 3-5 min to obtain browned cow milk; adding a sweetening agent, edible salt and tea powder into the browned cow milk, stirring uniformly, homogenizing, sterilizing, and then performing fermentation treatment, the yogurt product with the compound flavor of caramel and tea can be prepared by the application, and the yogurt product is suitable for consumers with lactose intolerance, and the audience range of the yogurt product is widened. Based on the browning condition of 100-120 DEG C for 3-5 min, the yogurt product suitable for sucking can be prepared.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a method for preparing yogurt and the yogurt itself. Background Technology

[0002] Yogurt is a dairy product made from cow's milk, goat's milk, or other milk through processes such as sterilization and fermentation. Yogurt not only has a rich taste but also offers health benefits such as aiding digestion, providing nutrition, and boosting immunity, making it very popular with consumers.

[0003] Compared to stirred yogurt, set yogurt uses a "filling before fermentation" production process, resulting in a uniform curd texture, a smoother and more delicate taste, and more complete nutrient retention.

[0004] Existing yogurts made with setters have poor absorbability, requiring consumers to scoop them out with a spoon. This cumbersome eating method complicates the process and limits consumer choice. Furthermore, existing setter yogurts offer limited flavor options and are unsuitable for consumers with lactose intolerance. Summary of the Invention

[0005] This invention provides a method for preparing yogurt and the yogurt itself, to solve the problem of poor edibility of existing coagulant-based yogurts.

[0006] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0007] In a first aspect, embodiments of the present invention provide a method for preparing yogurt, comprising:

[0008] Add lactase to the milk, stir well, and let it stand to hydrolyze.

[0009] Browned milk is obtained by browning enzymatically hydrolyzed milk at 100-120℃ for 3-5 minutes.

[0010] Sweeteners, salt, and tea powder are added to browned milk and stirred well. After homogenization and sterilization, the milk is fermented.

[0011] Optionally, browned milk comprises 89.8-93.89% of the total mass; and / or

[0012] Sweeteners comprise 6-10% of the total mass; and / or

[0013] Edible salt accounts for 0.06-0.10% of the total mass; and / or

[0014] Tea powder accounts for 0.05-0.10% of the total mass.

[0015] Optionally, the sweetener includes at least one of white sugar, glucose, fructose syrup, acesulfame potassium, sucralose, aspartame, saccharin, xylitol, erythritol, threose, sifidin, and maltitol.

[0016] Optionally, the tea powder includes at least one type of tea powder selected from green tea, white tea, yellow tea, oolong tea, black tea, and red tea.

[0017] Optionally, the enzymatic hydrolysis temperature is 40-45℃ and the enzymatic hydrolysis time is 1-1.5h.

[0018] Optionally, the sterilization temperature is 90-95℃, and the sterilization time is 5-25 minutes;

[0019] The homogenization temperature is 50-55℃, the first-stage homogenization pressure is 180-200 bar, and the second-stage homogenization pressure is 30-40 bar.

[0020] Optionally, the fermentation process includes:

[0021] Add a starter culture to the sterilized browned milk and ferment at 41-44℃ for 6-8 hours.

[0022] Optionally, the starter culture includes at least one of the following: Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus salivarius subsp. thermophilus, Lactococcus lactis subsp. lactis, Lactococcus fat, Bifidobacterium animalis subsp. lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus helveticus, Lactobacillus paracasei, Lactobacillus salivarius, Lactobacillus geranioli, Lactobacillus fermentum, and Lactobacillus acidophilus.

[0023] Optionally, the viable count of the fermentation strain in the starter culture is (1-5)×10⁻⁶. 10 CFU / g.

[0024] Secondly, embodiments of the present invention provide a yogurt prepared using the yogurt preparation method described in any one of the embodiments of the first aspect.

[0025] In this embodiment of the invention, lactase is added to milk, stirred evenly, and then allowed to stand for enzymatic hydrolysis. The hydrolyzed milk is then browned at 100-120℃ for 3-5 minutes to obtain browned milk. Sweetener, edible salt, and tea powder are added to the browned milk, stirred evenly, homogenized, sterilized, and then fermented. This embodiment of the invention can prepare a yogurt product with a complex flavor of caramel and tea, and is suitable for consumers with lactose intolerance, thus broadening the target audience for yogurt products. Based on the browning condition of 100-120℃ for 3-5 minutes, this embodiment of the invention improves the drinkability of the yogurt product and can prepare a set-type yogurt product suitable for consumption. Attached Figure Description

[0026] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0027] Figure 1 This is a schematic flowchart of the yogurt preparation method according to an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The terms "first," "second," etc., used in this embodiment of the invention are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same class, not limited in number; for example, the first object can be one or more. Furthermore, in this embodiment of the invention, "or" indicates at least one of the connected objects. For example, "A or B" covers three scenarios: Scenario 1: includes A but does not include B; Scenario 2: includes B but does not include A; Scenario 3: includes both A and B. The character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0030] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] It should be noted that all raw materials used in the embodiments of the present invention can be obtained commercially available. Any range described in the embodiments of the present invention includes the end value and any value between the end values, as well as any sub-range formed by the end value or any value between the end values.

[0032] This invention provides a method for preparing yogurt, see [link to relevant documentation]. Figure 1 As shown, Figure 1 This is a schematic flowchart of a yogurt preparation method according to an embodiment of the present invention. The yogurt preparation method includes:

[0033] Step 11: Add lactase to the milk, stir well, and let it stand for enzymatic hydrolysis;

[0034] Step 12: Brown the enzymatically hydrolyzed milk at 100-120℃ for 3-5 minutes to obtain browned milk;

[0035] Step 13: Add sweetener, salt, and tea powder to the browned milk, stir well, homogenize, sterilize, and then ferment.

[0036] In some embodiments of the present invention, optionally, the browning temperature can be any of the following temperatures: 100℃, 105℃, 110℃, 115℃, or 120℃. The browning time can be any of the following times: 3 min, 4 min, or 5 min.

[0037] In this embodiment of the invention, step 11 involves adding lactase to milk, stirring until homogeneous, and then allowing it to stand for enzymatic hydrolysis. This hydrolyzes the lactose in the milk, making the yogurt suitable for consumers who are lactose intolerant, thus broadening the target audience for yogurt.

[0038] In this embodiment of the invention, step 12 involves browning the enzymatically hydrolyzed milk at 100-120℃ for 3-5 minutes to obtain browned milk. Browning the milk imparts a caramel flavor and improves the taste of the yogurt.

[0039] In this embodiment of the invention, step 13 involves adding sweetener, salt, and tea powder to the browned milk, stirring thoroughly, homogenizing, sterilizing, and then fermenting. Adding sweetener increases the sweetness of the yogurt and neutralizes the acidity from subsequent fermentation, enriching its flavor. Adding salt enhances the flavor of the yogurt and also neutralizes the acidity, resulting in a more balanced taste. Adding tea powder increases the amount of tea polyphenols in the yogurt, giving it a tea flavor and aroma, enriching its taste, and increasing its appeal to consumers.

[0040] Homogenization breaks down milk fat globules into smaller particles, reducing their tendency to aggregate and float, thereby improving emulsion stability, preventing the formation of a creamy layer, and ensuring the yogurt product remains uniform during storage and transportation. Homogenization also makes the yogurt texture finer and smoother, improving its mouthfeel and enhancing the consumer's drinking experience.

[0041] In some alternative embodiments, sterilization may be pasteurization. Ultra-high pressure sterilization is preferred to ensure the elimination of bacteria while also protecting heat-sensitive nutrients in the browned milk, thus ensuring a highly nutritious yogurt.

[0042] In this embodiment of the invention, step 11 involves adding lactase to milk, stirring until homogeneous, and then allowing it to stand for enzymatic hydrolysis; step 12 involves browning the enzymatically hydrolyzed milk at 100-120℃ for 3-5 minutes to obtain browned milk; and step 13 involves adding sweetener, edible salt, and tea powder to the browned milk, stirring until homogeneous, sterilizing, and then fermenting. This embodiment of the invention can prepare a yogurt product with a complex flavor of caramel and tea, suitable for consumers with lactose intolerance, thus broadening the target audience for yogurt products. Based on the browning condition of 100-120℃ for 3-5 minutes, this embodiment of the invention improves the drinkability of the yogurt product, enabling the preparation of a set-type yogurt product suitable for consumption.

[0043] In some embodiments of the present invention, optionally,

[0044] Browned milk accounts for 89.8-93.89% of the total mass, for example, 90%, 91.5% or 93% of the total mass. The specific content can be selected according to the needs.

[0045] Optionally, the sweetener accounts for 6-10% of the total mass, for example, 6%, 8% or 10% of the total mass, and the specific content can be selected as needed.

[0046] Optionally, edible salt accounts for 0.06-0.10% of the total mass, for example, 0.06%, 0.08% or 0.10% of the total mass, and the specific content can be selected according to the needs.

[0047] Optionally, the tea powder accounts for 0.05-0.10% of the total mass, for example, 0.05%, 0.07% or 0.10% of the total mass. The specific content can be selected as needed.

[0048] In this embodiment of the invention, the flavor and texture of the yogurt are optimized by using the above-mentioned proportions.

[0049] In some embodiments of the present invention, the sweetener optionally includes at least one selected from granulated sugar, glucose, high-fructose corn syrup, acesulfame potassium, sucralose, aspartame, aspartame, saccharin, xylitol, erythritol, threose, sifrane, and maltitol. For example, the sweetener may include high-fructose corn syrup and erythritol, and the sweetener may include granulated sugar, xylitol, and erythritol; the specific content and type can be selected as needed.

[0050] In some embodiments of the present invention, the sweetener is preferably a compound sweetener obtained from at least two of the above-mentioned sugar substances. The compound sweetener enriches the types of sweetness in the yogurt and improves its flavor and texture. The sweetener also preferably includes at least one of acesulfame potassium, sucralose, aspartame, aspartame, xylitol, erythritol, threose, sifrane, and maltitol, i.e., using sugar substitutes, which reduces the calories in the yogurt and improves its health properties.

[0051] In some embodiments of the present invention, the tea powder may optionally include at least one type of tea powder selected from green tea, white tea, yellow tea, oolong tea, black tea, and red tea.

[0052] In some embodiments of the present invention, the tea powder is preferably a compound tea powder obtained from at least two of the above-mentioned teas, which improves the tea flavor and aroma in the yogurt and enhances its taste. In some embodiments, the tea powder is preferably black tea powder.

[0053] In some embodiments of the present invention, optionally, the enzymatic hydrolysis temperature is 40-45°C, and the enzymatic hydrolysis time is 1-1.5 h. This accelerates the hydrolysis of lactose by lactase and ensures that the lactose is completely hydrolyzed.

[0054] In some embodiments of the present invention, optionally, the sterilization temperature is 90-95°C and the sterilization time is 5-25 min;

[0055] The homogenization temperature is 50-55℃, the first-stage homogenization pressure is 180-200 bar, and the second-stage homogenization pressure is 30-40 bar.

[0056] In this embodiment of the invention, the sterilization temperature is 90-95℃ and the sterilization time is 5-25 minutes, which effectively kills bacteria, pathogens, and miscellaneous bacteria that interfere with the fermentation of lactic acid bacteria in browned milk, making the yogurt meet the food hygiene standards, extending the shelf life of the yogurt, and ensuring a high fermentation success rate of browned milk in the subsequent fermentation process.

[0057] In this embodiment of the invention, the homogenization temperature is 50-55℃, the primary homogenization pressure is 180-200 bar, and the secondary homogenization pressure is 30-40 bar. This breaks down the milk fat globules in browned milk into small particles, reducing their tendency to aggregate and float, thus improving the stability of the browned milk, preventing the formation of a cream layer, and ensuring that the yogurt product remains uniform during storage and transportation. It also makes the yogurt texture more delicate and smooth, improving the taste and making it smoother, thereby enhancing the consumer's drinking experience.

[0058] In some embodiments of the present invention, optionally, the fermentation step includes:

[0059] Add a starter culture to the sterilized browned milk and ferment at 41-44℃ for 6-8 hours to ferment the browned milk into a yogurt product.

[0060] In some optional embodiments, for set-type yogurt, the specific steps of fermentation may include: adding a starter culture to pasteurized browned milk, stirring thoroughly and filling the container, and fermenting at 41-44°C for 6-8 hours. In some optional embodiments, the fermentation endpoint may be an acidity of 70°T. Specifically, after fermenting at 41-44°C for 6-8 hours until the acidity reaches 70°T, the temperature is lowered to 4-6°C to terminate fermentation.

[0061] In some embodiments of the present invention, the fermentation temperature may optionally be any of the following temperatures: 41°C, 42°C, 43°C, or 44°C. The fermentation time may optionally be any of the following times: 6h, 7h, or 8h.

[0062] In some embodiments of the present invention, the fermenting agent may optionally include at least one of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus salivarius subsp. thermophilus, Lactococcus lactis subsp. lactis, Lactococcus fat subsp., Bifidobacterium animalis subsp. lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus helveticus, Lactobacillus paracasei, Lactobacillus salivarius, Lactobacillus geranioli, Lactobacillus fermentum, and Lactobacillus acidophilus.

[0063] In some embodiments of the present invention, optionally, the viable count of the fermentation strain in the fermentation agent is (1-5)×10⁻⁶. 10 CFU / g, through the above-mentioned live bacteria count index, effectively improved the fermentation success rate.

[0064] In some embodiments of the present invention, optionally, the viable count of the fermentation strain in the fermentation agent can be any of the following quantities: 1 × 10⁻⁶. 10 CFU / g, 2×10 10 CFU / g, 3×10 10 CFU / g, 4×10 10 CFU / g, 5×10 10 CFU / g.

[0065] In some embodiments of the present invention, optionally, a yogurt is prepared using the yogurt preparation method as described in any one of the embodiments of the present invention. The yogurt of the embodiments of the present invention possesses a complex flavor of caramel and tea, and is suitable for consumers with lactose intolerance, thus broadening the target audience for yogurt products. The yogurt of the embodiments of the present invention is also suitable for sipping.

[0066] The following description is based on specific embodiments:

[0067] Example 1

[0068] 1. Preparation of browned milk

[0069] Formula: 999.80g raw milk, 0.20g lactase.

[0070] Preparation process:

[0071] (1) Heat the raw milk to 40°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis;

[0072] (2) Incubation: The raw milk after enzymatic hydrolysis is heated to 100°C and kept warm for 5 minutes to obtain browned milk.

[0073] 2. Preparation of set-type yogurt

[0074] Formula: 918.40g browned milk, 80g white sugar, 0.8g edible salt, 0.8g instant black tea powder, 0.2U starter (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus), wherein the ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0075] Preparation process:

[0076] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0077] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 180 bar, and the pressure for the second homogenization is 30 bar.

[0078] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0079] (4) Cooling: Cool the sterilized base material to 45°C.

[0080] (5) Gel formation: Add the fermentation agent into the base material, stir for 5 minutes, and then fill it aseptically. Then ferment it at a temperature of 42°C for 6 hours. The final acidity is 70°T.

[0081] Example 2

[0082] 1. Preparation of browned milk

[0083] Formula: 999.80g raw milk, 0.20g lactase.

[0084] Preparation process:

[0085] (1) Heat the raw milk to 40°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1.5 hours for enzymatic hydrolysis;

[0086] (2) Incubation: The raw milk after enzymatic hydrolysis is heated to 120°C and kept warm for 3 minutes to obtain browned milk.

[0087] 2. Preparation of set-type yogurt

[0088] Formula: 918.40g browned milk, 80g white sugar, 0.8g salt, 0.8g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0089] Preparation process:

[0090] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0091] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 200 bar, and the pressure for the second homogenization is 40 bar.

[0092] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0093] (4) Cooling: Cool the sterilized base material to 45°C.

[0094] (5) Gel formation: Add the fermentation agent to the base material, stir for 5 minutes, and then fill it aseptically. Then ferment it at a temperature of 42°C for 8 hours. The final acidity is 70°T.

[0095] Example 3

[0096] 1. Preparation of browned milk

[0097] Formula: 999.80g raw milk, 0.20g lactase.

[0098] Preparation process:

[0099] (1) Heat the raw milk to 45°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis.

[0100] (2) Incubation: The raw milk after enzymatic hydrolysis is heated to 120°C and kept warm for 4 minutes to obtain browned milk.

[0101] 2. Preparation of set-type yogurt

[0102] Formula: 938.90g browned milk, 60g white sugar, 0.6g salt, 0.5g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0103] Preparation process:

[0104] (1) Ingredients: Heat browned milk to 50°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0105] (2) Homogenization: Homogenization is carried out at 50℃. The pressure for the first homogenization is 180 bar, and the pressure for the second homogenization is 30 bar.

[0106] (3) Sterilization: Sterilize at 90℃ for 25 minutes.

[0107] (4) Cooling: Cool the sterilized base material to 41°C.

[0108] (5) Gel formation: Add the fermentation agent into the base material, stir for 5 minutes, and then fill it aseptically. Then ferment it at a temperature of 41°C for 7 hours. The final acidity is 70°T.

[0109] Example 4

[0110] 1. Preparation of browned milk

[0111] Formula: 999.80g raw milk, 0.20g lactase.

[0112] Preparation process:

[0113] (1) Heat the raw milk to 45°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis.

[0114] (2) Incubation: The raw milk after enzymatic hydrolysis is heated to 120°C and kept warm for 4 minutes to obtain browned milk.

[0115] 2. Preparation of set-type yogurt

[0116] Formula: 918.00g browned milk, 80g white sugar, 1g salt, 1g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0117] Preparation process:

[0118] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 30 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0119] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 200 bar, and the pressure for the second homogenization is 40 bar.

[0120] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0121] (4) Cooling: Cool the sterilized base material to 45°C.

[0122] (5) Gel formation: Add the fermentation agent into the base material, stir for 5 minutes, and then aseptically fill it. Then ferment it at a temperature of 44°C for 7 hours. The final acidity is 70°T.

[0123] Comparative Example 1

[0124] 1. Preparation of browned milk

[0125] Formula: 999.80g raw milk, 0.20g lactase.

[0126] Preparation process:

[0127] (1) Heat the raw milk to 45°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis.

[0128] (2) Incubation: The raw milk after enzymatic hydrolysis is heated to 90°C and kept warm for 1 minute to obtain browned milk.

[0129] 2. Preparation of set-type yogurt

[0130] Formula: 918.4g browned milk, 80g white sugar, 0.8g salt, 0.8g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0131] Preparation process:

[0132] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0133] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 200 bar, and the pressure for the second homogenization is 40 bar.

[0134] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0135] (4) Cooling: Cool the sterilized base material to 45°C.

[0136] (5) Gel formation: Add the fermentation agent to the base material, stir for 5 minutes, and then fill it aseptically. Then ferment it at a temperature of 42°C for 5 hours. The final acidity is 70°T.

[0137] Comparative Example 2

[0138] 1. Preparation of browned milk

[0139] Formula: 999.80g raw milk, 0.20g lactase.

[0140] Preparation process:

[0141] (1) Heat the raw milk to 45°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis.

[0142] (2) Incubation: The raw milk after enzymatic hydrolysis is heated to 150°C and kept warm for 10 minutes to obtain browned milk.

[0143] 2. Preparation of set-type yogurt

[0144] Formula: 918.4g browned milk, 80g white sugar, 0.8g salt, 0.8g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0145] Preparation process:

[0146] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0147] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 200 bar, and the pressure for the second homogenization is 40 bar.

[0148] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0149] (4) Cooling: Cool the sterilized base material to 45°C.

[0150] (5) Gel formation: Add the fermentation agent to the base material, stir for 5 minutes, and then fill it aseptically. Then ferment at 42°C for 10 hours. The final acidity is 70°T.

[0151] Comparative Example 3

[0152] 1. Preparation of browned milk

[0153] Formula: 999.80g raw milk, 0.20g lactase.

[0154] Preparation process:

[0155] (1) Heat the raw milk to 45°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis.

[0156] (2) Incubation: The enzymatically hydrolyzed raw milk is heated to 115°C and incubated for 4 minutes to obtain browned milk.

[0157] 2. Preparation of set-type yogurt

[0158] Formula: 969.40g browned milk, 30g white sugar, 0.3g salt, 0.3g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0159] Preparation process:

[0160] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0161] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 200 bar, and the pressure for the second homogenization is 40 bar.

[0162] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0163] (4) Cooling: Cool the sterilized base material to 45°C.

[0164] (5) Gel formation: Add the fermentation agent to the base material, stir for 5 minutes, and then fill it aseptically. Then ferment it at a temperature of 42°C for 8 hours. The final acidity is 70°T.

[0165] Comparative Example 4

[0166] 1. Preparation of browned milk

[0167] Formula: 999.80g raw milk, 0.20g lactase.

[0168] Preparation process:

[0169] (1) Heat the raw milk to 45°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis.

[0170] (2) Incubation: The enzymatically hydrolyzed raw milk is heated to 115°C and incubated for 4 minutes to obtain browned milk.

[0171] 2. Preparation of set-type yogurt

[0172] Formula: 876.00g browned milk, 120g white sugar, 2g salt, 2g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0173] Preparation process:

[0174] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0175] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 200 bar, and the pressure for the second homogenization is 40 bar.

[0176] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0177] (4) Cooling: Cool the sterilized base material to 45°C.

[0178] (5) Gel formation: Add the fermentation agent to the base material, stir for 5 minutes, and then fill it aseptically. Then ferment it at a temperature of 42°C for 8 hours. The final acidity is 70°T.

[0179] Comparative Example 5

[0180] 1. Preparation of browned milk

[0181] Formula: 999.80g raw milk, 0.20g lactase.

[0182] Preparation process:

[0183] (1) Heat the raw milk to 45°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis.

[0184] (2) Incubation: The enzymatically hydrolyzed raw milk is heated to 115°C and incubated for 4 minutes to obtain browned milk.

[0185] 2. Preparation of set-type yogurt

[0186] Formula: 918.40g browned milk, 80g white sugar, 0.8g salt, 0.8g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0187] Preparation process:

[0188] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0189] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 150 bar, and the pressure for the second homogenization is 20 bar.

[0190] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0191] (4) Cooling: Cool the sterilized base material to 45°C.

[0192] (5) Gel formation: Add the fermentation agent to the base material, stir for 5 minutes, and then fill it aseptically. Then ferment it at a temperature of 42°C for 7 hours. The final acidity is 70°T.

[0193] Comparative Example 6

[0194] 1. Preparation of browned milk

[0195] Formula: 999.80g raw milk, 0.20g lactase.

[0196] Preparation process:

[0197] (1) Heat the raw milk to 45°C, add lactase, shear and stir for 5 minutes to disperse it evenly in the raw milk, and let it stand for 1 hour for enzymatic hydrolysis.

[0198] (2) Incubation: The enzymatically hydrolyzed raw milk is heated to 115°C and incubated for 4 minutes to obtain browned milk.

[0199] 2. Preparation of set-type yogurt

[0200] Formula: 918.40g browned milk, 80g white sugar, 0.8g salt, 0.8g instant black tea powder, 0.2U starter culture (containing Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus). The ratio of Streptococcus salivarius subsp. thermophilus to Lactobacillus delbrueckii subsp. bulgaricus is 1:1.

[0201] Preparation process:

[0202] (1) Ingredients: Heat browned milk to 55°C, add white sugar, edible salt, instant black tea powder, etc., and shear and stir for 20 minutes to evenly disperse it in browned milk to obtain browned milk base material.

[0203] (2) Homogenization: Homogenization is carried out at 55℃. The pressure for the first homogenization is 230 bar, and the pressure for the second homogenization is 60 bar.

[0204] (3) Sterilization: Sterilize at 95℃ for 5 minutes.

[0205] (4) Cooling: Cool the sterilized base material to 45°C.

[0206] (5) Gel formation: Add the fermentation agent to the base material, stir for 5 minutes, and then fill it aseptically. Then ferment it at a temperature of 42°C for 7 hours. The final acidity is 70°T.

[0207] Comparative Example 7

[0208] Formula: 943.38g raw milk, 30g erythritol, 20g light cream, 5g stabilizer, 0.12g steviol glycosides, 1g lactase, 0.2U starter culture (containing *Streptococcus thermophilus* subsp. *salivarius* and *Lactobacillus delbrueckii* subsp. *bulgaricus*). The ratio of *Streptococcus thermophilus* subsp. *salivarius* to *Lactobacillus delbrueckii* subsp. *bulgaricus* is 1:1.

[0209] Preparation process:

[0210] (1) First mixing: Mix raw milk with lactase until homogeneous.

[0211] (2) Lactase hydrolysis: The mixed liquid was heated to 40±2℃ and hydrolyzed at a constant temperature for 1 hour.

[0212] (3) Browning: The enzymatically hydrolyzed liquid is heated to 90-95℃ and heated in a sealed container for 4 hours to brown, thus obtaining the browned liquid.

[0213] (4) Secondary mixing: Cool the browned liquid to 70-75℃, add the stabilizer, light cream, erythritol and steviosides as specified in the formula and stir evenly.

[0214] (5) Homogenization: After mixing, homogenization is carried out at a temperature of 60-65℃ and a pressure of 20MPa.

[0215] (6) Sterilization: After homogenization, sterilization is carried out under the following conditions: 95±2℃ for 300s. After sterilization, the temperature of the liquid is reduced to below 10℃.

[0216] (7) Inoculate the strain online, stir evenly, heat the liquid to 41-43°C, fill into packaging containers, transfer to fermentation room for fermentation, fermentation temperature is 41-43°C, fermentation termination acidity is 70-75°T, fermentation time is 5-6 hours, after fermentation is completed, put into cold storage, cold storage temperature is 4-6°C.

[0217] Comparative Example 8

[0218] 1. Preparation of browned milk

[0219] Formula: 1000.00g of raw milk.

[0220] Preparation process:

[0221] Heat preservation: Heat the raw milk to 100℃ and keep it warm for 5 minutes to obtain browned milk.

[0222] 2. The preparation of set-type yogurt is the same as in Example 1, with a fermentation time of 6 hours.

[0223] Comparative Example 9

[0224] 1. Preparation of enzymatically hydrolyzed milk

[0225] Formula: 999.80g raw milk, 0.20g lactase.

[0226] Preparation process:

[0227] Heat raw milk to 40°C, add lactase, shear and stir for 5 minutes to evenly disperse it in the raw milk, let it stand for 1 hour for enzymatic hydrolysis to obtain enzymatically hydrolyzed milk;

[0228] 2. The preparation of set-type yogurt is the same as in Example 1, with a fermentation time of 5.5 hours.

[0229] The above embodiments and comparative examples were tested according to the following parameters:

[0230] (1) Thixotropy: The thixotropy of set yogurt was determined using an MCRxx2 rheometer. Each sample was tested three times and the average value was taken. The specific results are shown in Table 1.

[0231] (2) Viable bacteria count: The viable bacteria count was tested in accordance with the "GB 4789.35-2016 National Food Safety Standard for Microbiological Examination of Food - Lactic Acid Bacteria Examination". The viable bacteria count of yogurt samples was tested at 0 days, 7 days, 14 days, 21 days and 28 days of shelf life. Each sample was tested three times and the average value was taken. The specific results are shown in Table 1.

[0232] (3) Sensory evaluation: 60 professional evaluators (male-female ratio of 1:1) were randomly selected to evaluate the yogurt products based on four aspects: texture, taste, smell and palatability on the first day of shelf life. Each indicator was scored out of 10 points. Each sample was tested three times and the average value was taken. The sensory evaluation criteria are shown in Table 2 and the sensory evaluation results are shown in Table 3.

[0233] (4) Water separation rate: Set-type yogurt was left to stand at room temperature (30℃) and 4℃ for 1h, 2h and 3h, respectively. 100g of the sample was put into a centrifuge at 3000rpm / 5min, and the mass of the supernatant was weighed. The water separation rate of the sample was determined. The test was repeated three times and the average value was taken. The specific results are shown in Table 4.

[0234] Table 1. Thixotropy and viable cell count

[0235]

[0236] Maillard browning (browning treatment) is a series of complex reactions that occur between reducing sugars and amino acids or proteins under heating conditions. These reactions mainly produce flavor compounds and intermediate products. This series of reactions has a significant impact on the flavor, texture, and fermentation capacity of milk and yogurt made from browned milk.

[0237] The thixotropic ring area represents the time dependence of fluid viscosity, and a suitable thixotropic ring area also reflects the drinking experience of yogurt. Table 1 shows that the thixotropic ring areas of the prepared set-type yogurts indicate that the thixotropy of the yogurt decreases with increasing browning temperature and time. This is because the Maillard reaction causes cross-linking or denaturation of milk proteins, interfering with the acidification and aggregation of casein micelles.

[0238] The results of Examples 1-4 show that the browning conditions of 100-120℃ for 3-5 minutes used in the embodiments of the present invention can ensure that the proteins undergo appropriate cross-linking and enhance the gel network structure. Comparative Examples 1 and 9 showed insufficient or no browning, resulting in higher product viscosity and significantly impacting the texture and flavor of the yogurt. Comparative Example 2 showed that excessive browning leads to excessive cross-linking of proteins, preventing casein micelles from forming an effective and dense three-dimensional network structure, thus resulting in a loose gel structure and affecting the texture of the yogurt.

[0239] Homogenization pressure affects the viscosity of yogurt. Excessive homogenization pressure leads to excessive breakage of fat globules in milk, increasing the fat globules' ability to adsorb proteins and reducing the amount of free proteins involved in gel network formation, resulting in decreased viscosity, as shown in Comparative Example 6. Conversely, insufficient homogenization pressure results in larger fat globules, disrupting gel homogeneity and making the fat-protein complexes formed with proteins unstable, thus affecting the viscosity of yogurt, as shown in Comparative Example 5.

[0240] Table 1 shows that the degree of browning, the type and amount of ingredients added, and the viable count results all significantly affect the activity of the fermentation bacteria. A high degree of browning leads to the formation of compounds that affect the metabolism of lactic acid bacteria, resulting in prolonged fermentation time and a lower viable count, as seen in Comparative Examples 2 and 7. Metabolites in tea powder can also affect the metabolism of lactic acid bacteria, thus impacting microbial activity. Appropriate degrees of browning and ingredient amounts have a smaller impact on the activity of lactic acid bacteria; in Examples 1-4, the viable count of the yogurt at the end of its shelf life was >5 × 10⁻⁶. 7 CFU / mL.

[0241] Table 2 Sensory Evaluation Criteria

[0242]

[0243] Table 3 Sensory evaluation results

[0244] sample Organizational status taste odor Inhalability Example 1 8.31 8.23 7.82 8.99 Example 2 8.44 8.15 8.00 9.01 Example 3 8.54 8.22 8.01 9.23 Example 4 8.29 8.54 8.41 9.34 Comparative Example 1 7.13 6.81 7.12 5.23 Comparative Example 2 4.64 3.56 3.14 8.44 Comparative Example 3 8.25 7.29 6.89 8.35 Comparative Example 4 7.83 7.27 7.18 8.41 Comparative Example 5 6.77 7.21 7.32 6.58 Comparative Example 6 5.41 7.33 7.28 7.32 Comparative Example 7 8.01 6.45 6.95 5.33 Comparative Example 8 7.95 5.67 6.81 7.21 Comparative Example 9 8.05 3.35 4.03 5.60

[0245] Referring to the taste test results in Table 3, it can be seen that yogurt products prepared under different browning conditions, with varying types and amounts of added ingredients, and with different homogenization pressures exhibit certain differences in texture, flavor, and drinkability. Maillard browning affects the cross-linking and polymerization of proteins in milk. Examples 1-4 show that by adjusting the browning conditions and optimizing the types and proportions of added ingredients, as well as the homogenization pressure, the resulting yogurt has a delicate and smooth texture, good texture, rich and harmonious caramel and tea aromas, and good drinkability.

[0246] Comparative Examples 1-2 and 9 show that low or no browning results in insufficient caramel aroma, leading to an uncoordinated flavor profile. Additionally, the product exhibits high thixotropy and poor absorption. High browning results in an overly dark color, the production of undesirable flavor compounds such as bitter peptides during browning, and an unbalanced flavor profile. Furthermore, high levels of cross-linking or denaturation of milk proteins result in poor product texture.

[0247] Comparative Examples 3-4 show that if the amount of tea powder added to the ingredients is too low, the tea aroma will be weak; if the amount of tea powder added is too high, the tea flavor will be too strong, the taste will be bitter, and the color will be darker. At the same time, if the metabolites in the tea powder are too high, it will affect the metabolism of lactic acid bacteria, thus affecting the state of the yogurt.

[0248] Comparative Examples 5-6 show that excessively high homogenization pressure leads to saturation of protein adsorption by fat globules in milk, weakening gel strength. At the same time, high pressure also destroys the natural structure of milk proteins, reducing gel strength and resulting in loose gel with poor tissue condition. Conversely, excessively low homogenization pressure results in large fat globules that are unevenly distributed in the milk system, leading to unstable fat-protein complexes that affect the smoothness and absorbability of the product.

[0249] Comparative Example 7 shows that the yogurt prepared using its formula and process has high thixotropy, high viscosity, good texture, and rich caramel aroma, but lacks absorbency. This is due to the addition of a high amount of light cream, which increases the solids content of the product.

[0250] Comparative Example 8 shows that if milk is not enzymatically hydrolyzed before browning, it will have a weak reducing power due to the fact that milk contains only lactose. This results in a low ability to directly participate in the Maillard browning reaction and a weak ability to produce flavor compounds such as caramelized substances, leading to a single or bland flavor in the product.

[0251] Table 4 Water Diversion Rate

[0252]

[0253] By measuring the water separation rate of set-type yogurt, no water was separated after the products of Examples 1-4 were placed at 4℃ for 3 hours, and the water separation rate was ≤0.5% after being placed at room temperature for 3 hours. This indicates that the selection of appropriate browning conditions, the types and amounts of added ingredients, and the homogenization pressure have a crucial impact on the stability of yogurt. During browning, substances such as melanoidins are produced. Excessive melanoidins occupy protein binding sites, interfering with casein acidification and aggregation, leading to a loose yogurt structure and increased water separation rate. Excessive addition of tea-based substances affects microbial activity, similarly impacting the final product's state. Excessively high or low homogenization pressure significantly affects the structure of fat globules and proteins in milk, thus affecting the state of cross-linked structures, causing unstable product texture and increased water separation. Furthermore, the yogurt product of this invention has a simple formula and its water separation capacity is similar to that of the product prepared in Comparative Example 7; after being placed at room temperature for 3 hours, the water separation rate is ≤0.5%.

[0254] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0255] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A method for preparing yogurt, characterized in that, include: Add lactase to the milk, stir well, and let it stand to hydrolyze. Browned milk is obtained by browning enzymatically hydrolyzed milk at 100-120℃ for 3-5 minutes. Sweeteners, salt, and tea powder are added to browned milk and stirred well. After homogenization and sterilization, the milk is fermented.

2. The method for preparing yogurt according to claim 1, characterized in that, Browned milk comprised 89.8-93.89% of the total mass; and / or Sweeteners comprise 6-10% of the total mass; and / or Edible salt accounts for 0.06-0.10% of the total mass; and / or Tea powder accounts for 0.05-0.10% of the total mass.

3. The method for preparing yogurt according to claim 1 or 2, characterized in that, Sweeteners include at least one of the following: white sugar, glucose, fructose syrup, acesulfame potassium, sucralose, aspartame, aspartame, saccharin, xylitol, erythritol, threose, sifidin, and maltitol.

4. The method for preparing yogurt according to claim 1 or 2, characterized in that, Tea powder includes at least one type of tea powder from green tea, white tea, yellow tea, oolong tea, black tea, and red tea.

5. The method for preparing yogurt according to claim 1, characterized in that, The enzymatic hydrolysis temperature is 40-45℃, and the enzymatic hydrolysis time is 1-1.5h.

6. The method for preparing yogurt according to claim 1, characterized in that, The sterilization temperature is 90-95℃, and the sterilization time is 5-25 minutes; The homogenization temperature is 50-55℃, the first-stage homogenization pressure is 180-200 bar, and the second-stage homogenization pressure is 30-40 bar.

7. The method for preparing yogurt according to claim 1, characterized in that, The steps involved in the fermentation process include: Add a starter culture to the sterilized browned milk and ferment at 41-44℃ for 6-8 hours.

8. The method for preparing yogurt according to claim 7, characterized in that, The starter culture includes at least one of the following: Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus salivarius subsp. thermophilus, Lactococcus lactis subsp. lactis, Lactococcus fat subsp. animalis, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus helveticus, Lactobacillus paracasei, Lactobacillus salivarius, Lactobacillus geranioli, Lactobacillus fermentum, and Lactobacillus acidophilus.

9. The method for preparing yogurt according to claim 8, characterized in that, The viable count of the fermentation strain in the starter culture is (1-5)×10⁻⁶. 10 CFU / g.

10. A type of yogurt, characterized in that, The yogurt is prepared using the method described in any one of claims 1 to 9.

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