Tea yoghourt stored at normal temperature and preparation method thereof

Abstract

The invention provides tea yoghurt stored at normal temperature and a preparation method thereof, the preparation raw materials of the tea yoghurt stored at normal temperature comprise a milk base material, tea leaves and a fermentation strain, the milk base material comprises a normal-temperature yoghurt stabilizer and a tea flavor stabilizer, the normal-temperature yoghurt stabilizer comprises citrus fiber, seaweed meal and glutinous rice starch, and the tea flavor stabilizer comprises tea flavor. The tea flavor stabilizer comprises single cream, whey protein powder and casein powder; the tea leaves comprise a combination of black tea and oolong tea, and the black tea and the oolong tea are subjected to enzymolysis pretreatment. The tea yoghourt disclosed by the invention has tea flavor and has related character stability such as system tissue state stability, flavor stability and the like when being stored under a normal-temperature condition.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of dairy products, and particularly relates to a tea yogurt for normal-temperature storage and a preparation method thereof. BACKGROUND

[0002] With the enhancement of the health concept of consumers, the combination of additive-free yogurt and tea has become the demand of consumers. However, the yogurt combined with tea at present is low-temperature storage yogurt, which can only be stored for a short time and is prone to flavor attenuation and unstable organization state.

[0003] A zero-additive yogurt has been disclosed in CN117099846A, which only uses citrus fiber, seaweed powder and waxy rice starch as stabilizers. However, the yogurt system directly prepared into tea yogurt with tea powder has the problem of flavor attenuation during storage at normal temperature.

[0004] Therefore, in the field, how to obtain tea yogurt without flavor attenuation during normal-temperature storage is a technical problem to be solved. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a tea yogurt for normal-temperature storage and a preparation method thereof. The present application can overcome the problems of unstable organization state and flavor attenuation of tea-flavored yogurt during storage at normal temperature. The tea yogurt of the present application has tea flavor and related property stability such as system organization state stability, flavor stability and the like during storage at normal temperature.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] On the one hand, the present application provides a tea yogurt for normal-temperature storage. The preparation raw materials of the tea yogurt for normal-temperature storage include milk base, tea leaves and fermentation strains. The milk base includes normal-temperature yogurt stabilizer and tea flavor stabilizer. The normal-temperature yogurt stabilizer includes citrus fiber, seaweed powder and waxy rice starch. The tea flavor stabilizer includes whipped cream, whey protein powder and casein powder. The tea leaves include a combination of black tea and oolong tea, which are pretreated by enzymolysis.

[0008] In the present application, the use of normal-temperature yogurt stabilizer can ensure the stability of yogurt at normal temperature. The combination of black tea and oolong tea can obtain tea flavor suitable for normal-temperature yogurt. The use of tea flavor stabilizer improves the stability of flavor substances such as tea polyphenols and theanine in tea leaves, reduces the attenuation of tea flavor during the storage of normal-temperature yogurt, and improves the overall stability of yogurt system.

[0009] The present application releases the flavor substances in the tea leaves sufficiently by performing enzymatic pretreatment on the tea leaves, improves the content of tea flavor substances in the yogurt and the combination degree with fat, protein and other ingredients, and forms a more stable tea-flavored yogurt at room temperature.

[0010] Preferably, the milk base further comprises raw cow milk and white granulated sugar.

[0011] Preferably, the milk base comprises the following components by weight: raw cow milk 870-909 parts by weight (for example, 870 parts by weight, 880 parts by weight, 890 parts by weight, 900 parts by weight, 903 parts by weight, 905 parts by weight, or 909 parts by weight), white granulated sugar 70-90 parts by weight (for example, 70 parts by weight, 73 parts by weight, 75 parts by weight, 78 parts by weight, 80 parts by weight, 83 parts by weight, 85 parts by weight, 88 parts by weight, or 90 parts by weight), whipping cream 3-5 parts by weight (for example, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, or 5 parts by weight), whey protein powder 2-3 parts by weight (for example, 2 parts by weight, 2.3 parts by weight, 2.5 parts by weight, 2.8 parts by weight, or 3 parts by weight), casein powder 1-2 parts by weight (for example, 1 part by weight, 1.2 parts by weight, 1.5 parts by weight, 1.8 parts by weight, or 2 parts by weight), citrus fiber 1-4 parts by weight (for example, 1 part by weight, 2 parts by weight, 3 parts by weight, or 4 parts by weight), seaweed powder 2-6 parts by weight (for example, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, or 6 parts by weight), and waxy rice starch 12-20 parts by weight (for example, 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 and the oolong tea is 1:1-3:1, 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 the tea leaves to the 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 strain comprises Lactobacillus bulgaricus and Streptococcus thermophilus.

[0015] Preferably, the addition amount of the fermentation strain is 200 dcu / ton.

[0016] Preferably, the addition amount of Lactobacillus bulgaricus and Streptococcus thermophilus in the fermentation strain is in a ratio of 1:1.

[0017] Preferably, the method for the enzymatic pretreatment of tea leaves is: uniformly spraying an enzyme preparation solution onto the surface of tea leaves, performing enzymatic hydrolysis, then inactivating the enzyme and drying to obtain the enzymatically pretreated tea leaves.

[0018] Preferably, the enzyme preparation solution comprises cellulase and pectinase. Further preferably, the ratio of enzyme activity of the cellulase and pectinase is 3:1-5:1, such as 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, etc.

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

[0020] Preferably, the enzymatic hydrolysis is performed for 2-5 h, such as 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 by microwave inactivation, the microwave inactivation is performed at a power of 500-800 W (such as 500 W, 550 W, 600 W, 650 W, 700 W, 750 W or 800 W) for 1-2 min (such as 1 min, 1.3 min, 1.5 min, 1.8 min or 2 min).

[0022] In another aspect, the present application provides a method for preparing the tea yogurt for normal temperature storage as described above, the method comprising the following steps:

[0023] (1) adding normal temperature yogurt stabilizer and tea flavor stabilizer and white granulated sugar into warm raw milk and mixing, then performing homogenization;

[0024] (2) adding the enzymatically pretreated black tea and oolong tea into the milk base obtained in step (1) and performing sterilization after heating, then filtering;

[0025] (3) cooling the liquid obtained in step (2), then adding fermentation bacteria and performing fermentation to obtain fermented milk;

[0026] (4) sterilizing the fermented milk obtained in step (3), then cooling to obtain the tea yogurt for normal temperature storage.

[0027] Preferably, the warm raw milk in step (1) is raw milk with a temperature of 45-50℃ (such as 45℃, 47℃, 49℃ or 50℃).

[0028] Preferably, the mixing in step (1) is for a time period of 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, for example 55 °C, 57 °C, 59 °C or 60 °C.

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

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

[0032] In the present application, the temperature increase in step (2) also completes the extraction of the tea leaves during the sterilization process.

[0033] Preferably, the sterilization in step (2) is for a time period of 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 carried out using 80 mesh sterile filter cloth.

[0035] Preferably, the temperature decrease in step (3) is to a temperature of 41-43 °C.

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

[0037] In the present application, after the fermentation in step (3), the emulsion is broken by stirring and the temperature is decreased to 15-20 °C, for example 15 °C, 16 °C, 17 °C, 18 °C, 19 °C or 20 °C, to obtain fermented milk.

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

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

[0040] The present application applies the process of tea enzymatic pretreatment and milk base extraction of tea to the preparation of normal temperature tea yogurt, so that the flavor substances in tea are fully released, the content of tea flavor substances in yogurt is increased, and the combination degree with fat, protein and other ingredients is improved, forming a more stable tea flavor normal temperature yogurt.

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

[0042] The tea yogurt of the present application can maintain stable tea flavor and organization state under normal temperature storage conditions, the combination of black tea and oolong tea in tea is used to obtain suitable tea flavor of normal temperature yogurt, and the combination of whipped cream, whey protein powder and casein powder in the formula is used to improve the stability of flavor substances such as tea polyphenols and theanine in tea, reduce the attenuation of tea flavor during the storage of normal temperature yogurt, and improve the overall stability of yogurt system.

[0043] The present application fully releases the flavor substances in tea by enzymatic pretreatment of tea, improves the content of tea flavor substances in yogurt, and improves the combination degree with fat, protein and other ingredients, forming a more stable tea flavor normal temperature yogurt. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be further described by specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application, and should not be regarded as specific limitations on the present application.

[0045] In the following examples, the black tea is Dianhong, and the oolong tea is Dahongpao.

[0046] Example 1

[0047] This embodiment provides a normal temperature storage tea yogurt formula and preparation method, as follows:

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

[0049] Milk 899 parts by weight, light cream 3 parts by weight, whey protein powder 2 parts by weight, casein protein powder 1 part by weight, waxy rice starch 12 parts by weight, seaweed powder 2 parts by weight, citrus fiber 1 part by weight, and white granulated sugar 80 parts by weight; 10 parts by weight of tea leaves after pre-treatment by enzymolysis, of which 7.5 parts by weight of black tea and 2.5 parts by weight of oolong tea; the addition amount of fermentation strains (Lactobacillus bulgaricus and Streptococcus thermophilus) is 200 dcu / ton (the addition amount ratio of Lactobacillus bulgaricus to Streptococcus thermophilus is 1:1).

[0050] The method for pre-treatment of tea leaves by enzymolysis is to uniformly spray enzyme preparation solution (cellulase: pectinase = 3:1) onto the surface of tea leaves, control the temperature at 50℃, maintain the environmental humidity at 75%, and enzymolysis for 4 h. After enzymolysis, the tea leaves are dried by microwave under the condition of 500 W and 2 min to obtain the tea leaves treated by enzymolysis.

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

[0052] (1) Warm the milk to 45℃, and then add light cream, white granulated sugar, whey protein powder, casein protein powder, waxy rice starch, seaweed powder, and citrus fiber in sequence, and mix for 15 min. Warm to 60℃, and homogenize under the condition of total pressure 140 bar and secondary pressure 30 bar.

[0053] (2) Add the tea leaves treated by enzymolysis to the milk base obtained in step (1), warm to 95℃ and maintain for 5 min to sterilize and extract the tea leaves;

[0054] (3) Filter the material after sterilization in step (2) by using a sterile filter screen of 80 mesh;

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

[0056] (5) After pasteurization, cool the fermented milk obtained in step (4) to 25℃, and the pasteurization condition is heating at 75℃ for 15 s.

[0057] Example 2

[0058] This example provides a tea yogurt formula and preparation method for normal temperature storage, as follows:

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

[0060] Milk 880 parts by weight, light cream 5 parts by weight, whey protein powder 3 parts by weight, casein protein powder 2 parts by weight, waxy rice starch 20 parts by weight, seaweed powder 6 parts by weight, citrus fiber 4 parts by weight, and white granulated sugar 80 parts by weight; 10 parts by weight of tea leaves after pre-treatment by enzymolysis, including 5 parts by weight of black tea and 5 parts by weight of oolong tea; the addition amount of fermentation strains (Lactobacillus bulgaricus and Streptococcus salivarius thermophilus) is 200 dcu / ton (the addition amount ratio of Lactobacillus bulgaricus to Streptococcus salivarius thermophilus is 1:1).

[0061] The enzyme preparation solution (cellulase: pectinase = 3:1) is uniformly sprayed onto the surface of the tea leaves, the temperature is controlled at 45℃, the environmental humidity is maintained at 85%, and the enzymolysis is performed for 5 h. After enzymolysis, the tea leaves are dried by microwave under the condition of 800 W and 1 min to obtain the tea leaves treated by enzymolysis.

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

[0063] (1) The milk is warmed to 50℃, and then light cream, white granulated sugar, whey protein powder, casein protein powder, waxy rice starch, seaweed powder, and citrus fiber are added in sequence and mixed for 20 min. The temperature is warmed to 60℃, and homogenization is performed under the condition of total pressure 160 bar and secondary pressure 50 bar.

[0064] (2) The tea leaves treated by enzymolysis are added to the milk base obtained in step (1), the temperature is warmed to 95℃ and maintained for 10 min, and sterilization and extraction of the tea leaves are performed simultaneously.

[0065] (3) The material after sterilization in step (2) is filtered by using a sterile filter screen of 80 mesh.

[0066] (4) The material liquid obtained in step (3) is cooled to 43℃, and the fermentation agent is added. Fermentation is performed until the acidity is greater than 70°T. Demulsification is performed by stirring and cooling to 15℃ to obtain fermented milk.

[0067] (5) The fermented milk obtained in step (4) is subjected to pasteurization, and then cooled to 25℃. The pasteurization condition is heating at 75℃ for 15 s.

[0068] Example 3

[0069] The present embodiment provides a tea yogurt formula and preparation method for normal temperature storage, as follows:

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

[0071] Milk 909 parts by weight, light cream 3 parts by weight, whey protein powder 2 parts by weight, casein protein powder 1 part by weight, waxy rice starch 12 parts by weight, seaweed powder 2 parts by weight, citrus fiber 1 part by weight, and white granulated sugar 70 parts by weight; 10 parts by weight of tea leaves after pre-treatment by enzymolysis, of which 6 parts by weight of black tea and 4 parts by weight of oolong tea; the addition amount of fermentation strains (Lactobacillus bulgaricus and Streptococcus salivarius thermophilus) is 200 dcu / ton (the addition amount ratio of Lactobacillus bulgaricus and Streptococcus salivarius thermophilus is 1:1).

[0072] The method for pre-treatment of tea leaves by enzymolysis is to uniformly spray enzyme preparation solution (cellulase: pectinase = 5:1) onto the surface of tea leaves, control the temperature at 45℃, maintain the environmental humidity at 70%, and enzymolysis for 2h. After enzymolysis, the tea leaves are dried by microwave under the condition of 600W for 2min to obtain the tea leaves treated by enzymolysis.

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

[0074] (1) Warm the milk to 50℃, and then add light cream, white granulated sugar, whey protein powder, casein protein powder, waxy rice starch, seaweed powder, and citrus fiber in sequence, and mix for 18min. Homogenize at a total pressure of 160bar and a secondary pressure of 50bar after warming to 60℃.

[0075] (2) Add the tea leaves treated by enzymolysis to the milk base obtained in step (1), warm to 95℃ and maintain for 8min to sterilize and extract the tea leaves at the same time;

[0076] (3) Filter the material after sterilization in step (2) by using a sterile filter screen of 80mesh.

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

[0078] (5) After pasteurization, cool the fermented milk obtained in step (4) to 25℃, and the pasteurization condition is heating at 85℃ for 25s.

[0079] Example 4

[0080] This example provides a tea yogurt formula and preparation method for normal temperature storage, as follows:

[0081] The preparation raw material formula of tea yogurt is as follows:

[0082] Milk 870 parts by weight, light cream 5 parts by weight, whey protein powder 3 parts by weight, casein protein powder 2 parts by weight, waxy rice starch 20 parts by weight, seaweed powder 6 parts by weight, citrus fiber 4 parts by weight, and white granulated sugar 90 parts by weight; 10 parts by weight of tea leaves after pre-treatment by enzymolysis, of which 6 parts by weight of black tea and 4 parts by weight of oolong tea; the addition amount of fermentation strains (Lactobacillus bulgaricus and Streptococcus salivarius thermophilus) is 200 dcu / ton (the addition amount ratio of Lactobacillus bulgaricus and Streptococcus salivarius thermophilus is 1:1).

[0083] The method for pre-treatment of tea leaves by enzymolysis is to uniformly spray enzyme preparation solution (cellulase: pectinase = 3:1) onto the surface of tea leaves, control the temperature at 55℃, maintain the environmental humidity at 70%, and enzymolysis for 5 h. After enzymolysis, the tea leaves are dried by microwave under the condition of 500 W and 1 min to obtain the tea leaves treated by enzymolysis.

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

[0085] (1) Warm the milk to 48℃, and then add light cream, white granulated sugar, whey protein powder, casein protein powder, waxy rice starch, seaweed powder, and citrus fiber in sequence, and mix for 18 min. Homogenize at a total pressure of 150 bar and a secondary pressure of 40 bar after warming to 55℃.

[0086] (2) Add the tea leaves treated by enzymolysis to the milk base obtained in step (1), warm to 95℃ and maintain for 8 min to sterilize and extract the tea leaves at the same time;

[0087] (3) Filter the material after sterilization in step (2) by using a sterile filter screen of 80 mesh.

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

[0089] (5) After pasteurization, cool the fermented milk obtained in step (4) to 25℃, and the pasteurization condition is heating at 85℃ for 25 s.

[0090] Comparative Example 1

[0091] This comparative example provides a tea yogurt formula and preparation method for normal temperature storage, as follows:

[0092] The formula of tea yogurt is as follows:

[0093] Milk 898 parts by weight, waxy rice starch 14 parts by weight, seaweed powder 2 parts by weight, citrus fiber 1 part by weight, and white granulated sugar 80 parts by weight; tea powder 5 parts by weight in total; the addition amount of fermentation strains (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus) is 200 dcu / ton (the addition amount ratio of Lactobacillus delbrueckii subsp. bulgaricus to Streptococcus salivarius subsp. thermophilus is 1:1).

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

[0095] (1) The milk is warmed to 45℃, and the light cream, white granulated sugar, whey protein powder, casein powder, starch, seaweed powder, citrus fiber, and tea powder are added in sequence, and mixed for 15 min. Homogenization is performed under the conditions of warming to 60℃ and total pressure 140 bar and secondary pressure 30 bar.

[0096] (2) The milk base obtained in step (1) is warmed to 95℃ and maintained for 5 min for sterilization.

[0097] (3) The solution obtained in step (2) is cooled to 41℃, and the fermentation agent is added, and fermentation is performed until the acidity is greater than 70°T, and then demulsification stirring and cooling to 20℃ are performed to obtain fermented milk.

[0098] (4) The fermented milk obtained in step (3) is subjected to pasteurization and then cooled to 25℃, and the pasteurization conditions are heating at 75℃ for 15 s.

[0099] Comparative Example 2

[0100] The other ingredients and preparation method of this comparative example are the same as those of Example 1, except that this comparative example does not use light cream.

[0101] Comparative Example 3

[0102] The other ingredients and preparation method of this comparative example are the same as those of Example 1, except that this comparative example does not use whey protein powder and casein powder.

[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 of this comparative example are not subjected to enzymatic pretreatment.

[0105] Comparative Example 5

[0106] This comparative example provides a tea yogurt formula and preparation method for normal temperature storage, as follows:

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

[0108] Milk 899 parts by weight, light cream 3 parts by weight, waxy starch 13 parts by weight, microcrystalline cellulose 2 parts by weight, seaweed powder 2 parts by weight, citrus fiber 1 part by weight, and white granulated sugar 80 parts by weight; 10 parts by weight of tea leaves after pre-treatment by enzymolysis, including 7.5 parts by weight of black tea and 2.5 parts by weight of oolong tea; the addition amount of fermentation strains (Lactobacillus bulgaricus and Streptococcus thermophilus) is 200 dcu / ton (the addition amount ratio of Lactobacillus bulgaricus to Streptococcus thermophilus is 1:1).

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

[0110] Comparative Example 6

[0111] The ingredients and preparation method of the present comparative example are the same as those of Example 1, except that the tea leaves of the present comparative example are green tea leaves, and the addition amount is the sum of the addition amounts of black tea and oolong tea in Example 1, i.e. 10 parts by weight.

[0112] Comparative Example 7

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

[0114] Comparative Example 8

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

[0116] Comparative Example 9

[0117] The ingredients and preparation method of the present comparative example are the same as those of Example 1, except that the waxy starch in Example 1 is replaced by corn starch.

[0118] Sensory evaluation: The products produced in Examples 1-4 and Comparative Examples 1-8 are used as test samples, and tests are performed on the overall preference, tea flavor direction, tea flavor intensity, smoothness, and astringency, etc. The method is as follows: 30 people are randomly selected to form a test population, and they are trained on scoring of relevant evaluation indexes before tasting, so that each evaluator understands the scoring range of each index and the interval of scores when the index differs. After tasting, the 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) are scored by means of anonymous scoring. Except for astringency, the higher the score, the better the effect.

[0119] The results of sensory evaluation 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℃ for observation, and the results of the direct observation of the texture and flavor stability of the products during the 6-month shelf life are shown in Table 2.

[0124] Table 2

[0125]

[0126] Example 3

[0127] The products of the examples and comparative examples were placed at 25℃ for observation, and the results of the direct observation of the texture and flavor stability of the products during the 6-month shelf life are shown in Table 2.

[0128] Table 3

[0129]

[0130] The applicant states that the ambient-temperature-stored tea yogurt and the method for preparing the same of the present application are illustrated by the above examples, but the present application is not limited to the above examples, i.e., it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement on the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc., all fall within the protection scope and disclosure scope of the present application.

Claims

1. A tea-flavored yogurt that can be stored at room temperature, characterized in that, The raw materials for preparing the room-temperature stored tea yogurt include milk base, tea leaves, and 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, and the black tea and oolong tea have undergone enzymatic pretreatment.

2. The tea yogurt stored at room temperature according to claim 1, characterized in that, The milk base also includes raw milk and white sugar.

3. The tea yogurt stored at room temperature according to claim 2, characterized in that, The milk base material includes the following components in parts by weight: 870-909 parts raw milk, 70-90 parts white sugar, 3-5 parts light cream, 2-3 parts whey protein powder, 1-2 parts casein powder, 1-4 parts citrus fiber, 2-6 parts seaweed powder, and 12-20 parts glutinous rice starch.

4. The tea yogurt stored at room temperature according to claim 1, characterized in that, The weight ratio of the black tea to the oolong tea is 1:1 to 3:1; The weight ratio of tea leaves to milk base is 1:100-1:50; The fermentation strains include Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus; The amount of fermentation bacteria added is 200 dcu / ton; The ratio of *Lactobacillus delbrueckii* subsp. bulgaricus and *Streptococcus salivarius* subsp. thermophilus in the fermentation strain is 1:

1.

5. The tea yogurt stored at room temperature according to claim 1, characterized in that, The method for pretreatment of tea leaves by enzymatic hydrolysis is as follows: after mixing black tea and oolong tea leaves in a certain proportion, the enzyme preparation solution is evenly sprayed onto the surface of the tea leaves for enzymatic hydrolysis, and then the enzyme is inactivated and dried to obtain the tea leaves that have undergone enzymatic hydrolysis pretreatment. The enzyme preparation solution includes cellulase and pectinase; the enzyme activity ratio of cellulase and pectinase is 3:1-5:1; The solvent in the enzyme preparation solution is a buffer solution with a pH of 4.5-5.5; The enzymatic hydrolysis is carried out in an environment with a temperature of 40-55℃ and a humidity of 70%-85%. The enzymatic hydrolysis time is 2-5 hours; The enzyme inactivation is performed using microwave inactivation, with a power of 500-800 W and an inactivation time of 1-2 minutes.

6. A method for preparing tea yogurt stored at room temperature according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Add room temperature yogurt stabilizer, tea flavor stabilizer and white sugar to warm raw milk and mix, then homogenize; (2) Add black tea and oolong tea that have undergone enzymatic hydrolysis pretreatment to the milk base obtained in step (1), heat it to sterilize, and filter it; (3) Cool down the liquid obtained in step (2), and then add fermentation bacteria to ferment and obtain fermented milk; (4) Sterilize and cool the fermented milk obtained in step (3) to obtain the tea yogurt stored at room temperature.

7. The preparation method according to claim 6, characterized in that, The warm raw milk mentioned in step (1) is raw milk with a temperature of 45-50℃; The mixing time in step (1) is 15-20 min.

8. The preparation method according to claim 6, characterized in that, The homogenization in step (1) is carried out at a temperature of 55-60℃; The homogenization in step (1) is carried out 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 heating in step (2) is to raise the temperature to 90-95℃; The sterilization time in step (2) is 5-10 min; The filtration in step (2) is performed using an 80-mesh sterile filter cloth.

10. The preparation method according to any one of claims 6-9, characterized in that, The cooling described in step (3) is to cool down to 41-43℃; The fermentation described in step (3) is fermentation until the acidity is greater than 70°T; Step (3) involves breaking the emulsion, stirring, and cooling to 15-20°C after fermentation to obtain fermented milk; The sterilization in step (4) is pasteurization; the pasteurization temperature is 75-80℃ and the time is 15-25s.

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