A tea yogurt for normal temperature storage and a method for preparing the same

Abstract

The application provides a kind of tea yoghurt of normal temperature storage and its preparation method, the preparation raw material of the tea yoghurt of normal temperature storage includes milk base, tea and fermentation strain, the milk base includes normal temperature yoghurt stabilizer and tea flavor stabilizer, the normal temperature yoghurt stabilizer includes citrus fiber, seaweed powder and waxy rice starch, and the tea flavor stabilizer includes whipping cream, whey protein powder and casein powder;The tea includes the combination of black tea and oolong tea, and the black tea and oolong tea are pretreated by enzymolysis.The tea yoghurt of the application has tea flavor and has system organization state stability, flavor stability and other related property stability under normal temperature storage conditions.

Description

Technical Field

[0001] This invention belongs to the field of dairy product technology, specifically relating to a tea yogurt that can be stored at room temperature and its preparation method. Background Technology

[0002] As consumers become more health-conscious, the combination of additive-free yogurt and tea has become a consumer demand. However, currently available yogurts paired with tea are all refrigerated yogurts, which can only be stored for a short period of time and are prone to flavor degradation and unstable texture.

[0003] CN117099846A discloses a zero-additive yogurt that uses only citrus fiber, seaweed powder, and glutinous rice starch as stabilizers. However, when this yogurt system is directly mixed with tea powder to make tea yogurt, it suffers from flavor degradation during storage at room temperature.

[0004] Therefore, in this field, how to obtain tea yogurt that does not experience flavor degradation during room temperature storage is a technical problem that needs to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a tea-flavored yogurt that can be stored at room temperature and its preparation method. This invention overcomes the problems of unstable system structure and flavor degradation in tea-flavored yogurt when stored at room temperature. The tea-flavored yogurt of this invention retains its tea flavor and exhibits stability in system structure, flavor, and other related characteristics when stored at room temperature.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] On one hand, the present invention provides a room-temperature stored tea yogurt, the raw materials for which the room-temperature stored tea yogurt is prepared include a milk base, tea leaves and a fermentation starter, the milk base includes a room-temperature yogurt stabilizer and a tea flavor stabilizer, the room-temperature yogurt stabilizer includes citrus fiber, seaweed powder and glutinous rice starch, the tea flavor stabilizer includes light cream, whey protein powder and casein powder; the tea leaves include a combination of black tea and oolong tea, the black tea and oolong tea being pretreated by enzymatic hydrolysis.

[0008] In this invention, the stability of yogurt at room temperature can be ensured by using a room temperature yogurt stabilizer. The combination of black tea and oolong tea can obtain a tea flavor suitable for room temperature yogurt. By using a tea flavor stabilizer, the stability of flavor substances in tea, such as tea polyphenols and theanine, can be improved, the decay of tea flavor during the storage of room temperature yogurt can be reduced, and the overall stability of the yogurt system can be improved.

[0009] This invention pre-treats tea leaves with enzymatic hydrolysis, allowing the flavor compounds in the tea leaves to be fully released, increasing the content of tea flavor compounds in yogurt and the degree of binding with components such as fat and protein, resulting in a more stable tea-flavored room-temperature yogurt.

[0010] Preferably, the milk base also includes raw milk and white sugar.

[0011] Preferably, the milk base comprises the following components in parts by weight: 870-909 parts by weight of raw milk (e.g., 870, 880, 890, 900, 903, 905, or 909 parts by weight), 70-90 parts by weight of white sugar (e.g., 70, 73, 75, 78, 80, 83, 85, 88, or 90 parts by weight), 3-5 parts by weight of light cream (e.g., 3, 3.5, 4, 4.5, or 5 parts by weight), and 2-3 parts by weight of whey protein powder. The following amounts are per unit weight (e.g., 2 parts by weight, 2.3 parts by weight, 2.5 parts by weight, 2.8 parts by weight, or 3 parts by weight), 1-2 parts by weight of casein powder (e.g., 1 part by weight, 1.2 parts by weight, 1.5 parts by weight, 1.8 parts by weight, or 2 parts by weight), 1-4 parts by weight of citrus fiber (e.g., 1 part by weight, 2 parts by weight, 3 parts by weight, or 4 parts by weight), 2-6 parts by weight of seaweed powder (e.g., 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, or 6 parts by weight), and 12-20 parts by weight of glutinous rice starch (e.g., 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 19 parts by weight, or 20 parts by weight).

[0012] Preferably, the weight ratio of the black tea to the oolong tea is 1:1 to 3:1, for example, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.3:1, 2.5:1, 2.8:1 or 3:1.

[0013] Preferably, the weight ratio of tea leaves to milk base is 1:100-1:50, for example, 1:100, 1:98, 1:95, 1:90, 1:85, 1:80, 1:75, 1:70, 1:65, 1:60, 1:55 or 1:50.

[0014] Preferably, the fermentation strains include Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus.

[0015] Preferably, the amount of fermentation bacteria added is 200 dcu / ton.

[0016] Preferably, the ratio of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus in the fermentation strain is 1:1.

[0017] Preferably, the method for pretreatment of tea leaves by enzymatic hydrolysis is as follows: an enzyme preparation solution is evenly sprayed onto the surface of the tea leaves for enzymatic hydrolysis, followed by enzyme inactivation and drying to obtain the tea leaves that have undergone enzymatic hydrolysis pretreatment.

[0018] Preferably, the enzyme preparation solution includes cellulase and pectinase. More preferably, the enzyme activity ratio of cellulase and pectinase is 3:1-5:1, for example, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1.

[0019] Preferably, the enzymatic hydrolysis is carried out in an environment with a temperature of 40-55℃ (e.g., 40℃, 45℃, 48℃, 50℃, 53℃ or 55℃) and a humidity of 70%-85% (e.g., 70%, 73%, 75%, 78%, 80%, 83% or 85%).

[0020] Preferably, the enzymatic hydrolysis time is 2-5 h, for example 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h or 5 h.

[0021] Preferably, the enzyme inactivation is performed using microwave inactivation, with a power of 500-800 W (e.g., 500 W, 550 W, 600 W, 650 W, 700 W, 750 W or 800 W) and an inactivation time of 1-2 min (e.g., 1 min, 1.3 min, 1.5 min, 1.8 min or 2 min).

[0022] On the other hand, the present invention provides a method for preparing tea yogurt that can be stored at room temperature as described above, the method comprising the following steps:

[0023] (1) Add room temperature yogurt stabilizer, tea flavor stabilizer and white sugar to warm raw milk and mix, then homogenize;

[0024] (2) Add black tea and oolong tea that have undergone enzymatic hydrolysis pretreatment to the milk base obtained in step (1), heat to sterilize, and filter;

[0025] (3) Cool down the liquid obtained in step (2), and then add fermentation bacteria to ferment and obtain fermented milk;

[0026] (4) Sterilize and cool the fermented milk obtained in step (3) to obtain the tea yogurt stored at room temperature.

[0027] Preferably, the warm raw milk in step (1) is raw milk with a temperature of 45-50°C (e.g., 45°C, 47°C, 49°C or 50°C).

[0028] Preferably, the mixing time in step (1) is 15-20 min, for example 15 min, 16 min, 17 min, 18 min, 19 min or 20 min.

[0029] Preferably, the homogenization in step (1) is carried out at a temperature of 55-60°C (e.g., 55°C, 57°C, 59°C or 60°C).

[0030] Preferably, the homogenization in step (1) is carried out under a total pressure of 140-160 bar (e.g., 140 bar, 145 bar, 148 bar, 150 bar, 153 bar, 155 bar, 158 bar or 160 bar) and a secondary pressure of 30-50 bar (e.g., 30 bar, 35 bar, 38 bar, 40 bar, 45 bar, 48 bar or 50 bar).

[0031] Preferably, the temperature rise in step (2) is to 90-95°C, for example, 90°C, 91°C, 92°C, 93°C, 94°C or 95°C.

[0032] In this invention, the extraction of tea leaves is also completed during the process of heating and sterilization in step (2).

[0033] Preferably, the sterilization time in step (2) is 5-10 min, for example 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

[0034] Preferably, the filtration in step (2) is performed using an 80-mesh sterile filter cloth.

[0035] Preferably, the cooling in step (3) is to cool down to 41-43°C.

[0036] Preferably, the fermentation in step (3) is fermentation until the acidity is greater than 70°T, for example, it can be 73°T, 75°T, 78°T, 80°T, 83°T, 85°T, 88°T, 90°T, etc.

[0037] In this invention, after fermentation, the milk is broken, stirred and cooled to 15-20°C (e.g., 15°C, 16°C, 17°C, 18°C, 19°C or 20°C) in step (3) to obtain fermented milk.

[0038] Preferably, the sterilization in step (4) is pasteurization.

[0039] Preferably, the pasteurization temperature is 75-80℃, for example 75℃, 76℃, 77℃, 78℃, 79℃ or 80℃, and the time is 15-25s, for example 15s, 18s, 20s, 23s or 25s.

[0040] This invention applies the process of enzymatic hydrolysis pretreatment of tea leaves and extraction of tea leaves from milk base to the preparation of room-temperature tea yogurt, which allows the flavor substances in tea leaves to be fully released, increases the content of tea flavor substances in yogurt and the degree of binding with components such as fat and protein, and forms a more stable tea-flavored room-temperature yogurt.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The tea yogurt of this invention can maintain the stability of tea flavor and texture under room temperature storage conditions. The combination of black tea and oolong tea in the tea leaves obtains a suitable tea flavor for room temperature yogurt. Furthermore, the combination of light cream, whey protein powder and casein powder in the formula improves the stability of flavor substances in tea, such as tea polyphenols and theanine, reduces the decay of tea flavor during room temperature yogurt storage, and improves the overall stability of the yogurt system.

[0043] This invention pre-treats tea leaves with enzymatic hydrolysis, allowing the flavor compounds in the tea leaves to be fully released, increasing the content of tea flavor compounds in yogurt and the degree of binding with components such as fat and protein, resulting in a more stable tea-flavored room-temperature yogurt. Detailed Implementation

[0044] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0045] In the following embodiments, the black tea is Dianhong (Yunnan black tea) and the oolong tea is Da Hong Pao (Da Hong Pao).

[0046] Example 1

[0047] This embodiment provides a recipe and preparation method for tea yogurt that can be stored at room temperature, as follows:

[0048] The raw material formula for preparing tea yogurt is as follows:

[0049] The formula consists of 899 parts by weight of milk, 3 parts by weight of light cream, 2 parts by weight of whey protein powder, 1 part by weight of casein powder, 12 parts by weight of glutinous rice starch, 2 parts by weight of seaweed powder, 1 part by weight of citrus fiber, and 80 parts by weight of white sugar; 10 parts by weight of tea leaves after enzymatic hydrolysis pretreatment, including 7.5 parts by weight of black tea and 2.5 parts by weight of oolong tea; and 200 dcu / ton of fermentation bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus) (with a ratio of 1:1).

[0050] The method for pretreatment of tea leaves by enzymatic hydrolysis is as follows: An enzyme preparation solution (cellulase:pectinase = 3:1) is evenly sprayed onto the surface of the tea leaves, the temperature is controlled at 50℃, the ambient humidity is maintained at 75%, and enzymatic hydrolysis is carried out for 4 hours. After enzymatic hydrolysis, the enzyme is inactivated by microwave at 500 W for 2 minutes, and the tea leaves are then dried to obtain enzymatically hydrolyzed tea leaves.

[0051] The preparation method of tea yogurt is as follows:

[0052] (1) Heat the milk to 45°C, then add the heavy cream, white sugar, whey protein powder, casein powder, glutinous rice starch, seaweed powder, and citrus fiber in sequence, and mix for 15 min. Heat to 60°C and homogenize under a total pressure of 140 bar and a secondary pressure of 30 bar.

[0053] (2) Add the enzymatically hydrolyzed tea leaves to the milk base obtained in step (1), heat to 95°C and maintain for 5 min to sterilize and extract the tea leaves at the same time;

[0054] (3) Filter the sterilized material from step (2) using an 80-mesh sterile filter;

[0055] (4) Cool the liquid obtained in step (3) to 41°C, add the fermenting agent, ferment until the acidity is greater than 70°T, break the emulsion, stir and cool to 20°C to obtain fermented milk;

[0056] (5) After pasteurizing the fermented milk obtained in step (4), cool it to 25°C. The pasteurization conditions are heating at 75°C for 15 seconds.

[0057] Example 2

[0058] This embodiment provides a recipe and preparation method for tea yogurt that can be stored at room temperature, as follows:

[0059] The raw material formula for preparing tea yogurt is as follows:

[0060] The formula consists of 880 parts by weight of milk, 5 parts by weight of light cream, 3 parts by weight of whey protein powder, 2 parts by weight of casein powder, 20 parts by weight of glutinous rice starch, 6 parts by weight of seaweed powder, 4 parts by weight of citrus fiber, and 80 parts by weight of white sugar; 10 parts by weight of tea leaves after enzymatic hydrolysis pretreatment, including 5 parts by weight of black tea and 5 parts by weight of oolong tea; and 200 dcu / ton of fermentation bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus) (with a 1:1 ratio of Lactobacillus delbrueckii subsp. bulgaricus to Streptococcus salivarius).

[0061] The enzyme preparation solution (cellulase:pectinase = 3:1) was evenly sprayed onto the surface of the tea leaves. The temperature was controlled at 45℃, and the ambient humidity was maintained at 85%. Enzymatic hydrolysis was carried out for 5 hours. After enzymatic hydrolysis, the enzyme was inactivated by microwave at 800 W for 1 minute, and the tea leaves were dried to obtain enzymatically hydrolyzed tea.

[0062] The preparation method of tea yogurt is as follows:

[0063] (1) Heat the milk to 50°C, then add the heavy cream, white sugar, whey protein powder, casein powder, glutinous rice starch, seaweed powder, and citrus fiber in sequence, and mix for 20 min. Heat to 60°C and homogenize under a total pressure of 160 bar and a secondary pressure of 50 bar.

[0064] (2) Add the enzymatically hydrolyzed tea leaves to the milk base obtained in step (1), heat to 95°C and maintain for 10 min to sterilize and extract the tea leaves at the same time.

[0065] (3) Use an 80-mesh sterile filter to filter the material sterilized in step (2).

[0066] (4) Cool the liquid obtained in step (3) to 43°C, add the fermentation agent, ferment until the acidity is greater than 70°T, break the emulsion, stir and cool to 15°C to obtain fermented milk.

[0067] (5) After pasteurizing the fermented milk obtained in step (4), cool it to 25°C. The pasteurization conditions are heating at 75°C for 15 seconds.

[0068] Example 3

[0069] This embodiment provides a recipe and preparation method for tea yogurt that can be stored at room temperature, as follows:

[0070] The raw material formula for preparing tea yogurt is as follows:

[0071] The formula consists of 909 parts by weight of milk, 3 parts by weight of light cream, 2 parts by weight of whey protein powder, 1 part by weight of casein powder, 12 parts by weight of glutinous rice starch, 2 parts by weight of seaweed powder, 1 part by weight of citrus fiber, and 70 parts by weight of white sugar; 10 parts by weight of tea leaves after enzymatic hydrolysis pretreatment, including 6 parts by weight of black tea and 4 parts by weight of oolong tea; and 200 dcu / ton of fermentation bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus) (with a ratio of 1:1).

[0072] The method for pretreatment of tea leaves by enzymatic hydrolysis is as follows: An enzyme preparation solution (cellulase:pectinase = 5:1) is evenly sprayed onto the surface of the tea leaves, the temperature is controlled at 45℃, the ambient humidity is maintained at 70%, and enzymatic hydrolysis is carried out for 2 hours. After enzymatic hydrolysis, the enzyme is inactivated by microwave at 600 W for 2 minutes, and the tea leaves are then dried to obtain enzymatically hydrolyzed tea leaves.

[0073] The preparation method of tea yogurt is as follows:

[0074] (1) Heat the milk to 50°C, then add the heavy cream, white sugar, whey protein powder, casein powder, glutinous rice starch, seaweed powder, and citrus fiber in sequence, and mix for 18 min. Heat to 60°C and homogenize under a total pressure of 160 bar and a secondary pressure of 50 bar.

[0075] (2) Add the enzymatically hydrolyzed tea leaves to the milk base obtained in step (1), heat to 95°C and maintain for 8 min to sterilize and extract the tea leaves at the same time;

[0076] (3) Use an 80-mesh sterile filter to filter the material sterilized in step (2).

[0077] (4) Cool the liquid obtained in step (3) to 41°C, add the fermentation agent, ferment until the acidity is greater than 70°T, break the emulsion, stir and cool to 20°C to obtain fermented milk.

[0078] (5) After pasteurizing the fermented milk obtained in step (4), cool it to 25°C. The pasteurization conditions are heating at 85°C for 25 seconds.

[0079] Example 4

[0080] This embodiment provides a recipe and preparation method for tea yogurt that can be stored at room temperature, as follows:

[0081] The raw material formula for preparing tea yogurt is as follows:

[0082] The formula consists of 870 parts by weight of milk, 5 parts by weight of light cream, 3 parts by weight of whey protein powder, 2 parts by weight of casein powder, 20 parts by weight of glutinous rice starch, 6 parts by weight of seaweed powder, 4 parts by weight of citrus fiber, and 90 parts by weight of white sugar; 10 parts by weight of tea leaves after enzymatic hydrolysis pretreatment, including 6 parts by weight of black tea and 4 parts by weight of oolong tea; and 200 dcu / ton of fermentation bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus) (with a ratio of 1:1).

[0083] The method for pretreatment of tea leaves by enzymatic hydrolysis is as follows: An enzyme preparation solution (cellulase:pectinase = 3:1) is evenly sprayed onto the surface of the tea leaves, the temperature is controlled at 55℃, the ambient humidity is maintained at 70%, and enzymatic hydrolysis is carried out for 5 hours. After enzymatic hydrolysis, the enzyme is inactivated by microwave at 500 W for 1 minute, and the tea leaves are then dried to obtain enzymatically hydrolyzed tea leaves.

[0084] The preparation method of tea yogurt is as follows:

[0085] (1) Heat the milk to 48°C, then add the heavy cream, white sugar, whey protein powder, casein powder, glutinous rice starch, seaweed powder, and citrus fiber in sequence, and mix for 18 min. Heat to 55°C and homogenize under a total pressure of 150 bar and a secondary pressure of 40 bar.

[0086] (2) Add the enzymatically hydrolyzed tea leaves to the milk base obtained in step (1), heat to 95°C and maintain for 8 min to sterilize and extract the tea leaves at the same time;

[0087] (3) Use an 80-mesh sterile filter to filter the material sterilized in step (2).

[0088] (4) Cool the liquid obtained in step (3) to 41°C, add the fermentation agent, ferment until the acidity is greater than 70°T, break the emulsion, stir and cool to 15°C to obtain fermented milk.

[0089] (5) After pasteurizing the fermented milk obtained in step (4), cool it to 25°C. The pasteurization conditions are heating at 85°C for 25 seconds.

[0090] Comparative Example 1

[0091] This comparative example provides a recipe and preparation method for tea yogurt that can be stored at room temperature, as follows:

[0092] The recipe for tea yogurt is as follows:

[0093] The formula contains 898 parts by weight of milk, 14 parts by weight of glutinous rice starch, 2 parts by weight of seaweed powder, 1 part by weight of citrus fiber, and 80 parts by weight of white sugar; 5 parts by weight of tea powder; and 200 dcu / ton of fermentation bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus) (with a ratio of 1:1 between Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus).

[0094] The preparation method of tea yogurt is as follows:

[0095] (1) Heat the milk to 45°C, then add the heavy cream, white sugar, whey protein powder, casein powder, starch, seaweed powder, citrus fiber, and tea powder in sequence, and mix for 15 min. Heat to 60°C and homogenize under a total pressure of 140 bar and a secondary pressure of 30 bar.

[0096] (2) Heat the milk base obtained in step (1) to 95°C and maintain for 5 min to sterilize.

[0097] (3) Cool the liquid obtained in step (2) to 41°C, add the fermentation agent, ferment until the acidity is greater than 70°T, break the emulsion, stir and cool to 20°C to obtain fermented milk.

[0098] (4) After pasteurizing the fermented milk obtained in step (3), cool it to 25°C. The pasteurization conditions are heating at 75°C for 15 seconds.

[0099] Comparative Example 2

[0100] The other ingredients and preparation methods in this comparative example are the same as in Example 1, except that this comparative example does not use heavy cream.

[0101] Comparative Example 3

[0102] The other ingredients and preparation methods in this comparative example are the same as in Example 1, except that whey protein powder and casein powder are not used in this comparative example.

[0103] Comparative Example 4

[0104] The ingredients and preparation method of this comparative example are the same as those of Example 1, except that the tea leaves in this comparative example are not subjected to enzymatic pretreatment.

[0105] Comparative Example 5

[0106] This comparative example provides a recipe and preparation method for tea yogurt that can be stored at room temperature, as follows:

[0107] The raw material formula for preparing tea yogurt is as follows:

[0108] The formula consists of 899 parts by weight of milk, 3 parts by weight of light cream, 13 parts by weight of glutinous rice starch, 2 parts by weight of microcrystalline cellulose, 2 parts by weight of seaweed powder, 1 part by weight of citrus fiber, and 80 parts by weight of white sugar; 10 parts by weight of tea leaves after enzymatic hydrolysis pretreatment, including 7.5 parts by weight of black tea and 2.5 parts by weight of oolong tea; and 200 dcu / ton of fermentation bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus) (with a ratio of 1:1).

[0109] The preparation method of tea yogurt is the same as in Example 1.

[0110] Comparative Example 6

[0111] The ingredients and preparation method of this comparative example are the same as those of Example 1. The difference is that the tea used in this comparative example is green tea, and the amount added is the sum of the amounts of black tea and oolong tea used in Example 1, which is 10 parts by weight.

[0112] Comparative Example 7

[0113] The ingredients and other preparation methods of this comparative example are the same as those of Example 1, except that all the tea leaves used in this comparative example are black tea leaves, and the amount used is 10 parts by weight.

[0114] Comparative Example 8

[0115] The ingredients and preparation method of this comparative example are the same as those of Example 1, except that all the tea leaves used in this comparative example are oolong tea leaves, and the amount used is 10 parts by weight.

[0116] Comparative Example 9

[0117] The ingredients and preparation method of this comparative example are the same as those of Example 1, except that the glutinous rice starch in Example 1 is replaced with corn starch.

[0118] Sensory evaluation: Using the products produced in Examples 1-4 and Comparative Examples 1-8 as test samples, tests were conducted on overall preference, tea flavor direction, tea flavor intensity, smoothness, and astringency. The method was as follows: 30 people were randomly selected to form a test group. Before tasting, they were trained on the relevant evaluation indicators, ensuring each taster understood the scoring range for each indicator and the intervals for scoring when indicators differed. After tasting, anonymous scoring was used for overall preference (1-10 points), tea flavor direction (1-10 points), tea flavor intensity (1-10 points), smoothness (1-10 points), and astringency (1-10 points). Except for astringency, higher scores indicated better results.

[0119] The sensory evaluation results of the examples and comparative examples are shown in Table 1.

[0120] Table 1

[0121]

[0122] Example 2

[0123] The products of the examples and comparative examples were placed at 25°C for observation. The results of the texture and flavor stability of the products observed directly within the 6-month shelf life are shown in Table 2.

[0124] Table 2

[0125]

[0126] Example 3

[0127] The products from the examples and comparative examples were stored at 25°C. The centrifugal water loss rate of the products within a 6-month shelf life was tested. The test method was to centrifuge at 4000 r / min for 15 min, carefully aspirate and discard the upper whey layer with a syringe, and calculate the proportion of aspirated whey to the total mass of yogurt. The changes in centrifugal water loss rate are shown in Table 3.

[0128] Table 3

[0129]

[0130] The applicant declares that this invention illustrates the room-temperature stored tea yogurt and its preparation method through the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A room temperature stored tea yogurt, characterized in that, The preparation raw material of the normal-temperature stored tea yogurt comprises a milk base, tea leaves and fermentation bacteria, the milk base comprises a normal-temperature yogurt stabilizer and a tea flavor stabilizer, the normal-temperature yogurt stabilizer comprises citrus fiber, seaweed powder and waxy rice starch, and the tea flavor stabilizer comprises light cream, whey protein powder and casein powder; the tea leaves comprise a combination of black tea and oolong tea, and the black tea and oolong tea are subjected to enzyme pretreatment; The method for enzyme pretreatment of the tea leaves is as follows: after the black tea and oolong tea are mixed in a certain proportion, an enzyme preparation solution is uniformly sprayed on the surface of the tea leaves, enzyme hydrolysis is performed, and then enzyme inactivation and drying are performed to obtain the tea leaves subjected to enzyme pretreatment; the enzyme preparation solution comprises cellulase and pectinase; The black tea and oolong tea subjected to enzyme pretreatment are added to the milk base, sterilization is performed under heating, and then filtration is performed; the obtained material liquid is cooled, and then fermentation bacteria are added to perform fermentation to obtain fermented milk, sterilization is performed, and then cooling is performed to obtain the normal-temperature stored tea yogurt.

2. The ambient-stable tea yogurt according to claim 1, characterized in that, The milk base further comprises raw cow milk and white granulated sugar.

3. The ambient-stable tea yogurt according to claim 2, characterized in that, The milk base comprises the following components in parts by weight: 870-909 parts by weight of raw cow milk, 70-90 parts by weight of white granulated sugar, 3-5 parts by weight of light cream, 2-3 parts by weight of whey protein powder, 1-2 parts by weight of casein powder, 1-4 parts by weight of citrus fiber, 2-6 parts by weight of seaweed powder and 12-20 parts by weight of waxy rice starch.

4. The ambient-stable tea yogurt according to claim 1, characterized in that, The weight ratio of the black tea and oolong tea is 1:1-3:1; The weight ratio of the tea leaves to the milk base is 1:100-1:50; The fermentation bacteria comprise Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus; The addition amount of the fermentation bacteria is 200 dcu / ton; The addition amount of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus in the fermentation bacteria is in a ratio of 1:

1.

5. The ambient-stable tea yogurt according to claim 1, wherein The enzyme activity ratio of the cellulase and pectinase is 3:1-5:1; The solvent in the enzyme preparation solution is a buffer solution with a pH value of 4.5-5.5; The enzyme hydrolysis is performed in an environment with a temperature of 40-55°C and a humidity of 70%-85%; The enzyme hydrolysis time is 2-5 h; The enzyme inactivation is performed by microwave inactivation, the microwave inactivation power is 500-800 W, and the enzyme inactivation time is 1-2 min.

6. A process for the preparation of ambient-stable tea yogurt according to any one of claims 1 to 5, characterized in that, The preparation method comprises the following steps: (1) The normal-temperature yogurt stabilizer, tea flavor stabilizer and white granulated sugar are added to warm raw cow milk to mix, and then homogenization is performed; (2) The black tea and oolong tea subjected to enzyme pretreatment are added to the milk base obtained in step (1), sterilization is performed under heating, and then filtration is performed; (3) The material liquid obtained in step (2) is cooled, and then fermentation bacteria are added to perform fermentation to obtain fermented milk; (4) The fermented milk obtained in step (3) is sterilized and cooled to obtain the normal-temperature stored tea yogurt.

7. The production method according to claim 6, characterized by, In step (1), the warm raw cow milk is raw cow milk with a temperature of 45-50°C; In step (1), the mixing time is 15-20 min.

8. The preparation method according to claim 6, characterized in that, In step (1), the homogenization is performed at a temperature of 55-60°C; In step (1), the homogenization is performed under a total pressure of 140-160 bar and a secondary pressure of 30-50 bar.

9. The preparation method according to claim 6, characterized in that, The temperature rising in step (2) is rising to 90-95℃; The sterilization time in step (2) is 5-10 min; The filtration in step (2) is using 80 mesh sterile filter cloth to filter.

10. The production method according to any one of claims 6 to 9, characterized by, The temperature lowering in step (3) is lowering to 41-43℃; The fermentation in step (3) is fermenting to acidity greater than 70°T; After the fermentation in step (3), demulsification stirring is carried out and the temperature is lowered to 15-20℃ to obtain fermented milk; The sterilization in step (4) is pasteurization; the temperature of the pasteurization is 75-80℃ and the time is 15-25s.

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