Salad dressing made from green tea whey protein Pickering emulsion and its preparation method

Abstract

The present invention discloses a salad dressing of green tea whey protein Pickering emulsion and its preparation method. The salad dressing comprises 0.8 - 1.4% of whey protein, 50.0 - 70.0% of edible oil, 15.0 - 35.0% of tea soup, 0.2 - 0.5% of pectin, 0.4 - 0.7% of citric acid, 1.0 - 4.0% of white vinegar, 5.0 - 20.0% of sucrose, and 0.8 - 1.4% of table salt. On the one hand, taking whey protein as a raw material, the present invention solves the problem of the harm caused by high cholesterol to health. On the other hand, the combination of whey protein and green tea adds a special tea flavor to this product. The polyphenols in green tea are a strong antioxidant substance, which can effectively scavenge free radicals in the human body, block the process of lipid peroxidation in the human body, enhance the activity of substances in the human body, and can effectively prevent the oxidation of the salad dressing. By adopting a pre-aqueous phase sterilization process, the phenomenon of unstable emulsion structure caused by directly heating and sterilizing the emulsion is avoided.

Description

Technical Field

[0001] The present invention relates to the field of food technology, and specifically to a salad dressing made from green tea whey protein Pickering emulsion and its preparation method. Background Art

[0002] With the introduction of Western fast food, salad dressings are now increasingly popular among people. The popularization of healthy eating has led to the rapid development of salad-based foods. However, traditional salad dressings contain egg yolk components, and the cholesterol in them can have an adverse impact on the human cardiovascular system. In recent years, the preparation of nutritious and healthy salad dressings using protein-based Pickering emulsions has become a research hotspot.

[0003] 1. As disclosed in a Chinese patent for a yolk-free salad dressing and its preparation method (Publication No.: CN114098047A), it includes the following components by mass fraction: 5-15% of syrup, 5-15% of granulated sugar, 5-10% of starch, 1-4% of whey powder, 1-4% of whey protein, 30-60% of oil and fat, and 20-50% of water. Its preparation method is as follows: S1 Dissolve starch, whey powder, whey protein and colloid, and disperse evenly; S2 Mix syrup, granulated sugar, potassium sorbate and edible salt evenly, and heat until completely gelatinized; S3 Add to an emulsifying tank, add oil and fat, and emulsify and disperse; S4 Add citric acid to adjust the pH value, and stir evenly; S5 Hot fill, and cool to room temperature and pack in boxes. This salad dressing formula does not contain egg yolk and related products of egg yolk, and it does not require cold processing, reducing the processing cost.

[0004] 2. A low-fat egg-containing salad dressing and its preparation method (Publication No.: CN111657481A), the low-fat egg-containing salad dressing, by mass fraction, includes 20-60% of salad oil, 20-30% of sweet potato starch, 15-25% of egg yolk, 0-45% of ingredients, and Lactobacillus at 107-109 CFU / g is added after the raw materials are mixed. It meets the requirements of low fat, low calories and low cholesterol in most usage scenarios of salad dressings.

[0005] However, there are still many problems that have not been solved:

[0006] 1. Using traditional thermal sterilization will damage the structure of the emulsion and affect the taste of the salad dressing;

[0007] 2. The high cholesterol in the egg yolk of traditional salad dressings is harmful to human health;

[0008] 3. The high oil and fat content in salad dressings is prone to oxidation, which affects the shelf life and flavor of salad dressings. Summary of the Invention

[0009] In view of the deficiencies of the prior art, the present invention provides a salad dressing of green tea whey protein Pickering emulsion and its preparation method, which solves the technical problems in the prior art that the traditional heat sterilization method will damage the emulsion structure, the salad dressing is prone to oxidation and harmful to human health.

[0010] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0011] A salad dressing of green tea whey protein Pickering emulsion, calculated by mass percentage, includes the following raw materials: whey protein 0.8 - 1.4%, edible oil 50.0 - 70.0%, tea soup 15.0 - 35.0%, pectin 0.2 - 0.5%, citric acid 0.4 - 0.7%, white vinegar 1.0 - 4.0%, sucrose 5.0 - 20.0%, table salt 0.8 - 1.4%.

[0012] Preferably, calculated by mass percentage, it includes the following raw materials: whey protein 0.8%, corn oil 70.0%, tea soup 15.0%, pectin 0.3%, citric acid 0.4%, white vinegar 1.6%, sucrose 11.0%, table salt 0.8%.

[0013] Preferably, the tea soup is made from green tea leaves.

[0014] Preferably, the edible oil is selected from one of corn oil or soybean oil.

[0015] A preparation method of a salad dressing of green tea whey protein Pickering emulsion, including:

[0016] S1. Prepare the tea soup;

[0017] S2. First mixing: Add pectin and citric acid to the tea soup in step S1, seal and stir until dissolved, then add whey protein and stir again, followed by hydration treatment. After hydration treatment, add sucrose and stir until dissolved to obtain the first mixture;

[0018] S3. Water bath sterilization: Perform water bath sterilization on the first mixture and then cool it to obtain the sterilized mixture;

[0019] S4. Second mixing: Add white vinegar and table salt to the cooled sterilized mixture and stir to obtain the second mixture;

[0020] S5. Homogenization treatment: Add the edible oil to the second mixture for homogenization treatment.

[0021] Preferably, the method for preparing the tea soup in step S1 is: Add green tea leaves to 50 - 70 g of drinking water, place it in a water bath at 85°C - 95°C and heat for 12 min - 17 min, then filter the tea leaves while it is hot to obtain tea soup of different concentrations and cool it.

[0022] Preferably, the method for obtaining the first mixture in step S2 by adding pectin and citric acid to the tea soup in step S1, sealing and stirring until dissolved, then adding whey protein and stirring again followed by hydration treatment, and finally adding sucrose and stirring until dissolved is as follows:

[0023] Step (1) Add pectin powder and citric acid to the tea soup, then seal and stir rapidly for 4 h - 5 h to fully dissolve; <s>

[0024] Step (2) Slowly add whey protein powder to step (1), continue to seal and stir for 2 h - 3 h, and then hydrate at 4°C - 5°C for 4 h - 5 h;

[0025] Step (3) Add sucrose powder to step (2) and stir until dissolved.

[0026] Preferably, the method for obtaining the sterilized mixture by subjecting the first mixture in step S3 to water bath sterilization and then cooling is as follows:

[0027] Seal the first mixture in step S2, place it in a water bath at 65°C - 85°C for 30 - 35 min, and stir during the water bath state to heat evenly. After the water bath ends, cool it in cold water.

[0028] Preferably, the method for adding edible oil to the second mixture in step S5 for homogenization treatment is as follows:

[0029] Use a high - speed homogenizer to homogenize the edible oil and the second mixture at 8000 - 10000 rad / min for 30 s - 60 s.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] The salad dressing of green tea whey protein Pickering emulsion provided by the present invention has the characteristics of wide raw material sources, low raw material prices, simple production processes, being beneficial to human health, and good flavor, and is suitable for all ages. Using whey protein, which is rich in nutrition, low in price, and natural in composition, as the main raw material to prepare a Pickering emulsion - type salad dressing with a simple process. By adding polysaccharides, the stability of the salad dressing can be improved. The interaction between polysaccharides and proteins helps to form a firm emulsifying film, thereby enhancing the stability between emulsion droplets. The tea polyphenols in the tea soup not only extend the shelf life of the salad dressing due to inhibiting oil oxidation and spoilage, but also have the effects of inhibiting cardiovascular and cerebrovascular diseases and delaying aging.

[0032] The preparation method of the salad dressing of the green tea whey protein Pickering emulsion provided by the present invention is made from whey protein. On the one hand, it solves the problem of the harm caused by high cholesterol in egg yolks to health. On the other hand, the combination of whey protein and green tea adds a special tea flavor to this product. Moreover, the polyphenols in green tea are a strong antioxidant substance, which can effectively scavenge free radicals in the human body, block the process of lipid peroxidation in the human body, enhance the activity of substances in the human body, effectively prevent the occurrence of cancer, and also effectively prevent the oxidation of salad dressing. At the same time, the pre-aqueous phase sterilization process is adopted. Compared with the prior art of high-temperature sterilization after homogenization to form an emulsion, it avoids the phenomenon of unstable emulsion structure caused by directly heating and sterilizing the emulsion. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is the average particle size distribution diagram of the salad dressing in Example 1 and the salad dressings in Comparative Example 1 and Comparative Example 2;

[0034] Figure 2 It is the particle size distribution diagram of the salad dressing in Example 1 and the salad dressings in Comparative Example 1 and Comparative Example 2;

[0035] Figure 3 It is the viscosity diagram of the salad dressing in Example 1 and the commercially available salad dressing in Comparative Example 1;

[0036] Figure 4 It is the average particle size distribution diagram of the salad dressing in Example 2 after different heating sterilization methods;

[0037] Figure 5 It is the particle size distribution diagram of the salad dressing in Example 2 after different heating sterilization methods;

[0038] Figure 6 It is the change diagram of the primary oxidation products of the salad dressings in Example 1 and Comparative Example 3 placed in an oven at 60 °C for seven days;

[0039] Figure 7 It is the change diagram of the secondary oxidation products of the salad dressings in Example 1 and Comparative Example 3 placed in an oven at 60 °C for seven days. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0041] The present invention provides a technical solution: a salad dressing of green tea whey protein Pickering emulsion, by mass percentage, includes the following raw materials: whey protein 0.8 - 1.4%, edible oil 50.0 - 70.0%, tea soup 15.0 - 35.0%, pectin 0.2 - 0.5%, citric acid 0.4 - 0.7%, white vinegar 1.0 - 4.0%, sucrose 5.0 - 20.0%, table salt 0.8 - 1.4%.

[0042] The salad dressing of green tea whey protein Pickering emulsion provided by the present invention has the characteristics of wide raw material sources, low raw material prices, simple production processes, being beneficial to human health, and good flavor, and is suitable for all ages. The present invention uses whey protein, which is rich in nutrition, low in price, and natural in composition, as the main raw material to prepare a Pickering emulsion type salad dressing with a simple process. By adding polysaccharides, the stability of the salad dressing can be improved. The interaction between polysaccharides and proteins helps to form a firm emulsifying film, thereby improving the stability between emulsion droplets. The tea polyphenols in the tea soup not only extend the shelf life of the salad dressing due to oil oxidation deterioration, but also have the effects of inhibiting cardiovascular and cerebrovascular diseases and delaying aging.

[0043] As a preferred embodiment, the salad dressing of green tea whey protein Pickering emulsion comprises the following raw materials by mass percentage: 0.8% of whey protein, 70.0% of corn oil, 15.0% of tea soup, 0.3% of pectin, 0.4% of citric acid, 1.6% of white vinegar, 11.0% of sucrose, and 0.8% of table salt.

[0044] In this embodiment, the tea soup is made from green tea leaves, and the edible oil is selected from one of corn oil or soybean oil.

[0045] Please refer to Figures 1 - 7 , the present invention also provides a preparation method of a salad dressing of green tea whey protein Pickering emulsion, comprising:

[0046] Step S1, preparing tea soup;

[0047] Step S2, first mixing. Add pectin and citric acid to the tea soup in step S1, seal and stir until dissolved, then add whey protein and stir again, followed by hydration treatment. After hydration treatment, add sucrose and stir until dissolved to obtain the first mixture;

[0048] Step S3, water bath sterilization. Perform water bath sterilization on the first mixture and then cool it to obtain the sterilized mixture;

[0049] Step S4, second mixing: Add white vinegar and table salt to the cooled sterilized mixture and stir to obtain the second mixture;

[0050] Step S5, homogenization treatment. Add edible oil to the second mixture for homogenization treatment.

[0051] Among them, the method for preparing tea soup in step S1 is: Add green tea leaves to 50 - 70 g of drinking water, place it in a water bath at 85°C - 95°C and heat for 12 min - 17 min, then filter the tea leaves while it is hot to obtain tea soup with different concentrations and cool it.

[0052] In step S2, the method for obtaining the first mixture by adding pectin and citric acid to the tea soup in step S1, sealing and stirring until dissolved, then adding whey protein and stirring again followed by a hydration treatment, and finally adding sucrose and stirring until dissolved is as follows:

[0053] Step (1): Add pectin powder and citric acid to the tea soup, then seal and stir rapidly for 4 h - 5 h to fully dissolve.

[0054] Step (2): Slowly add whey protein powder to step (1), continue to seal and stir at medium speed for 2 h - 3 h, and then hydrate at 4 °C - 5 °C for 4 h - 5 h.

[0055] Step (3): Add sucrose powder to step (2) and stir until dissolved.

[0056] In step S3, the method for obtaining the sterilized mixture by subjecting the first mixture to water bath sterilization and then cooling is as follows:

[0057] Seal the first mixture in step S2, place it in a water bath at 65 °C - 85 °C for 30 - 35 min, and stir at a low speed in the water bath state to heat evenly. After the water bath, cool it in cold water.

[0058] In step S4, the method for obtaining the second mixture by adding white vinegar and table salt to the cooled sterilized mixture and stirring is: Add white vinegar and table salt to the cooled sterilized mixture and stir at medium speed for 2 min.

[0059] In step S5, the method for adding edible oil to the second mixture for homogenization treatment is as follows:

[0060] Use a high-speed homogenizer to homogenize the edible oil and the second mixture at 8000 - 10000 rad / min for 30 s - 60 s.

[0061] Compared with the prior art, the preparation method of the salad dressing of green tea whey protein Pickering emulsion provided by the present invention is made with whey protein as the raw material. On the one hand, it solves the problem of the harm to health caused by high cholesterol in egg yolks. On the other hand, the combination of whey protein and green tea adds a special tea flavor to this product. Moreover, polyphenolic substances in green tea are a strong antioxidant, which can effectively scavenge free radicals in the human body, block the process of lipid peroxidation in the human body, enhance the activity of substances in the human body, effectively prevent the occurrence of cancer, and also effectively prevent the oxidation of salad dressing. At the same time, by adopting the pre-aqueous phase sterilization process, compared with the prior art of performing high-temperature sterilization after homogenizing to form an emulsion, it avoids the phenomenon of unstable emulsion structure caused by directly heating and sterilizing the emulsion.

[0062] A preparation method of a salad dressing of green tea whey protein Pickering emulsion is as follows:

[0063] 1) Preparation of tea soup: Add 1 g, 5 g, 10 g, 15 g, 30 g of green tea leaves to 60 g of drinking water, place them in a 90 °C water bath for 15 min, and then filter the tea leaves while it is hot to obtain tea soups with different concentrations and wait for them to cool.

[0064] 2) Mixing: Attention should be paid to step - by - step mixing during mixing. One - time mixing of auxiliary materials will cause the Pickering emulsion system not to form. The steps of mixing are as follows: ① Add pectin powder and citric acid to the tea soup, seal it, and stir quickly for 4 h to fully dissolve; ② Slowly add whey protein powder to step ①, continue to seal and stir at medium speed for 2 h, and then hydrate at 4 °C for 4 h; ③ Add sucrose powder to step ② and stir until dissolved.

[0065] 3) Sterilization: Seal the solution in step 2), place it in an 85 °C water bath for 30 min, and stir slowly during this process to heat evenly. After the water bath, quickly cool it in cold water.

[0066] 4) Mixing: Add white vinegar and salt to the cooled solution and stir at medium speed for 2 min.

[0067] 5) Homogenization: Use a high - speed homogenizer to homogenize the edible oil and the solution in step 4) at 8000 - 10000 rad / min for 30 - 60 s. Finally, obtain a salad dressing with a green tea flavor based on whey protein Pickering emulsion.

[0068] Among them, the reagents and instruments used are as follows: The whey protein is food - grade whey protein powder, purchased from Shanghai Yuanye Bio - Technology Co., Ltd.; the edible oil is preferably corn oil, purchased from COFCO Fulinmen Group Co., Ltd.; pectin, sucrose, and citric acid are all purchased from Henan Huarui Bio - Technology; the white vinegar is Lee Kum Kee brewed pure rice vinegar, purchased from Lee Kum Kee Group; the salt is Yunhe brand green refined iodized salt, purchased from Hubei Salt Industry Group Co., Ltd.; the tea leaves are commercially available ordinary green tea leaves; the water used is all C'estbon purified water, purchased from China Resources C'estbon Beverage Co., Ltd.; table - top homogenizer: FJ200 - SH, Shanghai HuXi; stirring is carried out using a magnetic stirrer: THZ - 82(A), Changzhou Ronghua Instrument Manufacturing Co., Ltd.; water bath is carried out using a water bath pot: HH - 4 digital display constant temperature water bath pot, Jintan Jerry Electrical Appliance Co., Ltd.

[0069] Example 1

[0070] This example provides a preparation method of a salad dressing with green tea - whey protein Pickering emulsion. The specific steps for making this salad dressing are as follows:

[0071] 1) Preparation of tea soup: Add 10 parts of green tea leaves to 60 parts of drinking water, place them in a 90 °C water bath for 15 min, and then filter the tea leaves while it is hot to obtain tea soups with different concentrations and wait for them to cool.

[0072] 2) Mixing: The steps of mixing are as follows: ① Add 0.74 parts of pectin powder and 1.11 parts of citric acid to 40.45 parts of tea soup, seal and stir quickly for 4 h to fully dissolve; ② Slowly add 2.22 parts of whey protein powder to step ①, continue to seal and stir at medium speed for 2 h, and then hydrate at 4 °C for 4 h; ③ Add 29.60 parts of sucrose powder to step ② and stir until dissolved.

[0073] 3) Aqueous phase sterilization: Seal the solution in step 2) and place it in a water bath at 85 °C for 30 min. Stir slowly during this process to make the heating uniform, and quickly cool it in cold water after the water bath ends.

[0074] 4) Mixing: Add 4.45 parts of white vinegar and 2.22 parts of table salt to the cooled solution and stir at medium speed for 2 min.

[0075] 5) Homogenization: Use a high-speed homogenizer to homogenize 70 parts of edible oil and 30 parts of the solution in step 4) at 10000 rad / min for 60 s. Finally, a salad dressing of green tea whey protein Pickering emulsion is obtained.

[0076] Comparative Example 1

[0077] Use commercially available Kewpie salad dressing, and its ingredients are: vegetable oil, water, white granulated sugar, egg yolk, vinegar, table salt, food additives (sodium glutamate, xanthan gum, steviol glycoside, sucralose, disodium ethylenediaminetetraacetate), concentrated lemon juice, spices.

[0078] Comparative Example 2

[0079] Adopt the method of Example 1, the difference is that instead of preheating the aqueous phase, directly homogenize 30 parts of the prepared aqueous solution and 70 parts of edible oil at 10000 rad / min for 60 s, and the obtained salad dressing is sealed and placed in a water bath at 85 °C for 30 min to achieve the purpose of sterilization.

[0080] As Figure 1 shown in the particle size comparison of the salad dressings in Example 1 and Comparative Example 2 with the commercially available salad dressing in Comparative Example 1, from Figure 1 it can be seen that the average particle size of the salad dressing in Example 1 is the smallest, and the average particle size of the salad dressing in Comparative Example 2 is the largest. The smaller the particle size of the emulsion, the more difficult it is for the oil phase component of the emulsion to precipitate from the emulsion, which is beneficial to maintaining the stable tissue state and delicate texture of the Pickering emulsion salad dressing. Therefore, the sterilization process of pre-sterilizing the aqueous solution in Example 1 can achieve the structural stability of the salad dressing. It can be seen from the physical pictures that the salad dressings in Example 1 and the commercially available salad dressing in Comparative Example 1 both have good tissue structures, while there is oil precipitation in the salad dressing in Comparative Example 2. Figure 2 Further shows that the particle size of the salad dressing in Example 1 is small and the particle size distribution is uniform. Figure 3The viscosity of the salad dressing in Example 1 is greater than that of the commercially available salad dressing in Comparative Example 1. The greater the viscosity of the emulsion system, the slower the rate of phenomena such as sedimentation and coagulation of the emulsion, indicating that the emulsion system of the salad dressing in Example 1 is more stable and has a finer state.

[0081] Example 2 uses the same method as Example 1, with the difference that different sterilization methods are used for the aqueous phase. The aqueous phase is heated in a water bath at 25°C, 65°C, 85°C, and 100°C for 30 minutes, and autoclaved at 121°C for 15 minutes.

[0082] As Figure 4 and Figure 5 shown, they are the average particle size and particle size distribution diagram of the salad dressing in Example 2 after different heat sterilization methods respectively. Four different temperatures of water bath sterilization were selected according to pasteurization, boiling water sterilization, and autoclaving methods. The results show that the average particle size of pasteurization is smaller among the three sterilization methods, and the average particle size of the salad dressing prepared by heating the aqueous phase at 85°C for 30 minutes is the smallest. Heating treatment above 100°C will cause the denaturation degree of whey protein in the aqueous phase to be severe, which is not conducive to the adsorption of protein at the interface, and thus the particle size of the Pickering emulsion type salad dressing formed is larger. The particle size distribution diagram also further shows that the particle size distribution of the salad dressing after heat treatment of the aqueous phase at 100°C and 121°C moves towards a larger particle size overall.

[0083] Comparative Example 3

[0084] The same method as Example 1 is used, with the difference that the tea soup is replaced by pure water.

[0085] Figure 6 and Figure 7As shown, the changes in the primary and secondary oxidation products of the salad dressings in Example 1 and Comparative Example 3 after being placed in an oven at 60 °C for seven days are presented. The product of lipid primary oxidation is lipid hydroperoxide, which is an important indicator for measuring oil oxidation. Lipid hydroperoxides can polymerize to produce polymers or decompose themselves to produce aldehydes, ketones, and aromatic compounds, seriously affecting the quality and safety of oils. Moreover, the generation of lipid hydroperoxides will further accelerate the formation of secondary oxidation products of oils and thus accelerate oil oxidation. The primary oxidation products are unstable and will continue to undergo oxidation reactions to form secondary oxidation products. The secondary oxidation products will further decompose to produce small-molecule substances such as aldehydes, ketones, acids, and aromatics, which will further degrade the quality and safety of the oils. The content of secondary oxidation products is usually determined by measuring the content of malondialdehyde. It can be seen from the figure that the contents of lipid hydroperoxides and malondialdehyde in the salad dressing during the oxidation process increase with the prolongation of the pro-oxidation time. The contents of lipid hydroperoxides and malondialdehyde are in the order of Example 1 > Comparative Example 3, indicating that the salad dressing prepared by adding tea soup can, to a certain extent, hinder the oxidation of oils. Because the tea polyphenols contained in green tea soup have the effect of inhibiting oil oxidation reactions. Therefore, the Pickering emulsion-type salad dressing after adding green tea soup has good anti-oil oxidation properties.

[0086] Comparative Example 4

[0087] The same method as in Example 1 was used, with the difference that the corn oil used was not pure oil. Green tea leaves were added to the corn oil, heated in a water bath at 90 °C for 15 min, and then the tea leaves were filtered while it was still hot to obtain corn oil containing tea polyphenols, which was used after cooling.

[0088] Comparative Example 5

[0089] The same method as in Example 1 was used, with the differences that pure water was directly used to dissolve the ingredients, green tea leaves were added to the corn oil, heated in a water bath at 90 °C for 15 min, and then the tea leaves were filtered while it was still hot to obtain corn oil containing tea polyphenols, which was used after cooling.

[0090] Example 3

[0091] The same method as in Example 1 was used, with the difference that soybean oil was used.

[0092] Comparative evaluation

[0093] The salad dressings described in Example 1, 3 and Comparative Examples 1-2, 4-5 were distributed to 10 people for sensory evaluation. The sensory characteristics of the salad dressings were divided into 5 parts: color, aroma, taste, physical state, and tea flavor, and scored from 1 to 5 points, with 1 point being the most dissatisfied and 5 points being very satisfied. The evaluation results were averaged, and the evaluation criteria are shown in Table 1, and the sensory evaluation results are shown in Table 2.

[0094] Table 1 Sensory Evaluation Criteria

[0095] Item Scoring Criteria Score Color (1 - 5) The overall color is uniform, bright 5 Aroma (1 - 5) Sour - salty or sweet - sour smell, with the smell that salad dressing should have 5 Taste (1 - 5) Smooth taste, no abnormal smell 5 Appearance (1 - 5) Fine and uniform semi - solid state, no obvious oil separation or layering 5 Tea flavor (1 - 5) Fresh and refreshing, no bitterness 5

[0096] Table 2 Sensory Evaluation Results

[0097] Color Aroma Taste Appearance Tea flavor Total Score Example 1 3 5 5 4 5 22 Comparative Example 2 2 3 3 2 3 13 Comparative Example 4 1 4 2 2 2 11 Comparative Example 5 2 4 2 4 1 13 Example 3 3 4 4 5 3 19 Comparative Example 1 5 4 5 5 0 19

[0098] It can be seen from the sensory evaluation results in Table 2 that the overall sensory evaluation result of Example 1 is the best, indicating that both the salad dressing of the green tea whey protein Pickering emulsion of the present invention and the commercially available salad dressing products are in good condition. The salad dressing of the present invention also adds the flavor of green tea and a smooth taste.

[0099] Eggs are the main raw materials in traditional salad dressings and play an emulsifying role. However, since eggs may carry Salmonella, Staphylococcus aureus, etc., there are potential food hygiene and safety hazards in directly consuming them. The salad dressing in Example 1 was subjected to microbial detection, and the detection results are shown in Table 3 Hygiene Index.

[0100] Table 3 Hygiene Index

[0101]

[0102]

[0103] It can be seen from Table 3 that the process of pre-sterilizing the aqueous phase can also meet the hygiene requirements of the salad dressing, and adding citric acid and white vinegar during the preparation of the salad dressing of the green tea whey protein Pickering emulsion of the present invention is not conducive to the growth of microorganisms.

[0104] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, should be covered by the protection scope of the present invention.

Claims

1. Salad dressing of green tea whey protein Pickering emulsion, characterized in that, By mass percentage, it includes the following raw materials: whey protein 0.8 - 1.4%, edible oil 50.0 - 70.0%, tea soup 15.0 - 35.0%, pectin 0.2 - 0.5%, citric acid 0.4 - 0.7%, white vinegar 1.0 - 4.0%, sucrose 5.0 - 20.0%, salt 0.8 - 1.4%; It also includes a preparation method of a salad dressing with green tea whey protein Pickering emulsion, and this method includes: S1. Prepare the tea soup; S2. First mixing: Add pectin and citric acid to the tea soup in step S1, seal and stir until dissolved, then add whey protein and stir again, followed by hydration treatment. After hydration treatment, add sucrose and stir until dissolved to obtain the first mixture; S3. Water bath sterilization: After subjecting the first mixture to water bath sterilization, cool it to obtain the sterilized mixture. The method is: Seal the first mixture in step S2 and place it in a water bath at 65°C - 85°C for 30 - 35 min, and stir during the water bath state to heat evenly. After the water bath ends, cool it in cold water; S4. Second mixing: Add white vinegar and salt to the cooled sterilized mixture and stir to obtain the second mixture; S5. Homogenization treatment: Add edible oil to the second mixture for homogenization treatment.

2. The salad dressing of the green tea whey protein Pickering emulsion according to claim 1, characterized in that By mass percentage, it includes the following raw materials: whey protein 0.8%, corn oil 70.0%, tea soup 15.0%, pectin 0.3%, citric acid 0.4%, white vinegar 1.6%, sucrose 11.0%, salt 0.8%.

3. The salad dressing of the green tea whey protein Pickering emulsion according to claim 1, characterized in that: The tea soup is made from green tea leaves.

4. The salad dressing of the green tea whey protein Pickering emulsion according to claim 1, characterized in that: The edible oil is selected from one of corn oil or soybean oil.

5. The salad dressing of the green tea whey protein Pickering emulsion according to claim 1, characterized in that: The method for preparing the tea soup in step S1 is: Add green tea leaves to 50 - 70 g of drinking water, place it in a water bath pot at 85°C - 95°C and heat for 12 - 17 min, then filter the tea leaves while it is hot to obtain tea soup with different concentrations and cool it.

6. The salad dressing of the green tea whey protein Pickering emulsion according to claim 1, wherein: The method for adding pectin and citric acid to the tea soup in step S1 in step S2, sealing and stirring until dissolved, then adding whey protein and stirring again, followed by hydration treatment, and then adding sucrose and stirring until dissolved to obtain the first mixture is: Step (1): Add pectin powder and citric acid to the tea soup, seal and stir rapidly for 4 - 5 h to fully dissolve; Step (2): Slowly add whey protein powder to step (1), continue to seal and stir for 2 - 3 h, and then hydrate at 4°C - 5°C for 4 - 5 h; Step (3): Add sucrose powder to step (2) and stir until dissolved.

7. The salad dressing of the green tea whey protein Pickering emulsion according to claim 1, characterized in that: The method for adding edible oil to the second mixture for homogenization treatment in step S5 is: Use a high - speed homogenizer to homogenize the edible oil and the second mixture at 8000 - 10000 rad / min for 30 - 60 s.

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