Industrialized processing method of traditional tea leaf egg

Abstract

The present application belongs to the technical field of food processing. The present application provides an industrialized processing method of traditional tea leaf eggs, comprising the following steps: baking eggs, steaming and curing; making the egg shell crack by low-frequency vibration to obtain cracked egg shells; preparing a brine by mixing green oranges, black tea, spices, salt, soy sauce, monosodium glutamate, white granulated sugar and water, placing the brine and the cracked egg shells in a pressure container, heating the brine and marinating, circulating the brine during marinating, and obtaining marinated eggs; vacuum cooling and dehydrating the marinated eggs, removing the shells, vacuum packaging, high-temperature sterilization, and obtaining tea leaf eggs. The present application uses baking treatment to reduce the gelation of egg white, so that the protein of the prepared tea leaf eggs is more tender. The present application uses baking treatment, low-frequency vibration and vacuum cooling and dehydration to promote the flavor of the tea leaf eggs. The present application uses low-frequency vibration and vacuum cooling and dehydration to strengthen the crack texture of the tea leaf eggs. The present application uses high-temperature sterilization to prolong the shelf life of the tea leaf eggs.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to an industrial processing method for traditional tea eggs. Background Technology

[0002] Tea eggs are a traditional type of braised egg product, loved for their delicate texture and unique flavor. In traditional tea egg processing, the eggs are often braised for a long time to enhance the flavor. Furthermore, to extend shelf life, commercially available vacuum-packed braised eggs are mostly high-temperature sterilized products. This high-temperature sterilization results in a firmer texture and a slightly inferior taste compared to traditional non-high-temperature braised eggs. Patent CN 112889908 B uses a single medium-temperature sterilization method (105℃, 40-60 minutes) to better preserve the original fatty acid composition of the braised eggs; however, the shelf life at room temperature is only about 10 weeks, which is insufficient to meet the shelf-life requirement of more than 6 months for commercially available leisure braised eggs. While direct sterilization at 115-121℃ can achieve the required shelf life, the texture becomes too hard due to the high-intensity heat denaturation of the protein, resulting in a significantly different taste from traditionally braised tea eggs. Therefore, the key to restoring the taste, flavor, and appearance of traditional tea-braised eggs lies in how to innovate processing methods to ensure that tea eggs with long shelf life can quickly absorb flavor, maintain good tenderness after sterilization, and restore the surface texture of tea eggs. Summary of the Invention

[0003] [Technical Issues]

[0004] Commercially available vacuum-packed braised eggs are mostly sterilized at high temperatures, resulting in firmer eggs with a poorer taste. Meanwhile, tea eggs sterilized at medium temperatures often fail to meet shelf-life requirements. There is an urgent need for an industrial processing method for tea eggs that allows for rapid flavor absorption, good tenderness, restoration of surface cracks, and a longer shelf life.

[0005] [Technical Solution]

[0006] The first objective of this invention is to provide an industrial processing method for traditional tea eggs, comprising the following steps:

[0007] (1) Baking and cooking: Baking eggs, heating them with steam, and steaming them to obtain cooked eggs;

[0008] (2) Low-frequency vibration cracking: The cooked egg is vibrated at a low frequency to cause cracks in the eggshell, resulting in a cracked egg.

[0009] (3) Circulating high-temperature braising: Prepare braising liquid with green tangerines, black tea, spices, salt, soy sauce, MSG, white sugar and water. Place the braising liquid and cracked eggs in a pressure vessel, heat the braising liquid and braise. Circulate the braising liquid during braising to obtain braised eggs.

[0010] (4) Vacuum cooling and dehydration: Vacuum cooling and dehydration of the boiled eggs to obtain dehydrated eggs;

[0011] (5) Shell removal and packaging: Remove the shells from the dehydrated eggs, vacuum pack them, and obtain packaged eggs;

[0012] (6) High-temperature sterilization: Sterilize the packaged eggs to obtain tea eggs.

[0013] In one embodiment of the present invention, in step (1), the baking temperature is 40-60°C and the baking time is 2-4 hours.

[0014] In one embodiment of the present invention, in step (1), the temperature is raised to 85-100°C and the steaming time is 15-30 minutes.

[0015] In one embodiment of the present invention, in step (1), a steam oven is used for baking and steaming.

[0016] In one embodiment of the present invention, in step (2), the amplitude of the low-frequency vibration is 2-4 mm, the frequency is 10-20 Hz, and the duration of the low-frequency vibration is 3-6 s.

[0017] In one embodiment of the present invention, in step (2), a linear vibrator is used to crack the shell at low frequency.

[0018] In one embodiment of the present invention, in step (3), the amount of each ingredient in the brine is as follows, based on the weight percentage of water: 0.05-0.1% green tangerine, 0.5-2% black tea, 0.5-2% spices, 2-4% salt, 2-10% soy sauce, 0.5-2% monosodium glutamate, and 1-8% white sugar.

[0019] The spices are seasonings made from dried plant seeds, fruits, roots, and bark, which have the effect of stimulating appetite and improving the flavor of food.

[0020] In one embodiment of the present invention, in step (3), the weight ratio of brine to cracked eggs is 1 to 1.5:1.

[0021] The pressure vessel is a container that can increase the boiling point of the braising liquid by increasing the air pressure, so that the braising liquid reaches a higher temperature without boiling, thereby accelerating the braising efficiency of food.

[0022] In one embodiment of the present invention, in step (3), the pressure vessel is a brine pot.

[0023] In one embodiment of the present invention, in step (3), heating the brine means heating the brine to 102-105°C.

[0024] In one embodiment of the present invention, in step (3), the braising time is 3 to 5 hours.

[0025] In one embodiment of the present invention, in step (3), the brine is circulated for 3 to 8 minutes every 10 to 20 minutes.

[0026] The circulating brine is prepared by using a circulating centrifugal pump to ensure uniform distribution of the solutes in the brine.

[0027] In one embodiment of the present invention, in step (4), the vacuum degree of vacuum dehydration is -0.06 to -0.08 MPa, and the vacuum dehydration time is 15 to 25 min.

[0028] In one embodiment of the present invention, in step (5), an egg peeling machine is used to remove the shell of the dehydrated egg by rotation.

[0029] In one embodiment of the present invention, in step (6), the sterilization temperature is 115-121°C and the sterilization time is 13-20 min.

[0030] A second objective of this invention is to provide tea eggs prepared using the above-described method.

[0031] A third objective of this invention is to provide the application of the aforementioned tea eggs in the food industry.

[0032] Beneficial effects:

[0033] The industrial processing method of this invention differs from the traditional processing method for tea eggs. This invention involves baking the fresh-shelled eggs, which reduces the viscosity of the egg white and decreases its gelation properties. This results in a more tender protein texture in the tea eggs produced through subsequent heat treatment, making them easier to flavor. Furthermore, baking in the shell causes a slight loss of water in the egg white, allowing for faster and more thorough flavor absorption during the subsequent high-temperature braising process.

[0034] The industrial processing method of this invention uses low-frequency vibration to break the shell, ensuring that the shell membrane is not broken while causing the eggshell to crack, simulating the artificial shell-breaking process, so that the produced tea eggs have the crack texture of traditional tea eggs and promote the absorption of flavor.

[0035] The industrial processing method of this invention adopts a circulating high-temperature braising process, which allows for more thorough flavor absorption. The braising liquid is circulated regularly, resulting in better flavor absorption.

[0036] The industrial processing method of this invention uses vacuum cooling dehydration, which allows the tea eggs to cool down rapidly after braising. This avoids the product from staying in the temperature range of 20°C to 50°C, where bacteria multiply rapidly, for too long, thus preventing excessive proliferation of microorganisms and maintaining the high quality of the product. Vacuum cooling dehydration can also increase the salt content of the tea eggs, cause the brine on the surface of the eggs to evaporate, and enhance the formation of crack textures in the tea eggs.

[0037] The industrial processing method of the present invention combines baking treatment at 40-60℃ with high-temperature sterilization. Baking treatment at 40-60℃ helps to offset the increase in protein chewiness caused by high-temperature sterilization, thus extending the shelf life of tea eggs while maintaining the original chewiness of tea eggs before sterilization.

[0038] The tea eggs produced by this invention have a long shelf life, are not too chewy, have a good taste, are fully flavored, and have the typical crack texture of tea eggs. Attached Figure Description

[0039] Figure 1 The image shows the appearance of the tea egg prepared in Example 1. Detailed Implementation

[0040] The detection and analysis methods involved in this invention are as follows:

[0041] (1) The weight loss rate of baked eggs is calculated using the following formula:

[0042]

[0043] (2) Determination of the viscosity of egg white in shelled eggs: Take shelled eggs before and after baking, separate the egg white, filter the egg white with gauze, and use a DV-1 rotational viscometer to measure the viscosity. After the reading stabilizes, the viscosity value is measured.

[0044] (3) The texture of the tea eggs was determined using a texture analyzer: the chewiness of the samples was determined using the TPA texture analysis method. The egg white samples were cut into small pieces of 1.0cm × 1.0cm × 0.5cm. The probe was positioned 10mm above the sample surface. The testing conditions were: pre-test speed 5.0mm / s, test speed 2.0mm / s, and post-test speed 2.0mm / s. A P36R flat-bottomed cylindrical aluminum probe was used to compress the egg white to 60% of its original height. The contact force was Auto-5.0g.

[0045] (4) The salt content in tea egg protein was determined by silver nitrate titration, as follows: 10 mL of 0.1 mol / L AgNO3 and 5 mL of HNO3 (30%, v / v) were added to 2 g of sample, and the mixture was sheared at 5000 rpm for 2 min. The mixture was then gently boiled on a hot plate, cooled to room temperature, and 2.5 mL of FeNH4(SO4)2·12H2O (5%, w / w) was added. The mixture was then titrated with 0.1 mol / L KSCN standard solution until the solution became a stable light brown color. The NaCl content was determined as follows:

[0046]

[0047] Where V1 is the volume of AgNO3 solution (mL), N1 is the concentration of AgNO3 solution (mol / L), V2 is the volume of KSCN solution consumed (mL), N2 is the concentration of KSCN solution (mol / L), and M is the weight of the sample (g).

[0048] Example 1

[0049] An industrial processing method for traditional tea eggs includes the following steps:

[0050] (1) Baking and cooking: After washing the eggs, place them on a tray and put them in a steam oven. Bake the eggs at 40°C for 4 hours, then use steam to raise the temperature to 85°C and steam for 30 minutes to obtain cooked eggs.

[0051] (2) Low-frequency vibration to crack the shell: The cooked egg is vibrated at a low frequency in a linear vibrator to make the shell crack, thus obtaining a cracked egg; the amplitude of the low-frequency vibration is 2mm, the frequency is 10Hz, and the duration of the low-frequency vibration is 6s.

[0052] (3) Circulating high-temperature braising: Prepare braising broth with green tangerines, black tea, spices, salt, soy sauce, MSG, white sugar and water. Place cracked eggs in a special stacked steaming basket. Place the basket and braising broth in a braising broth tank (pressure vessel). After covering, heat the braising broth to 102℃ using a steam jacket and braise for 5 hours. During braising, the broth is circulated in the braising broth tank for 5 minutes every 15 minutes by a circulating broth pump to obtain braised eggs. The weight percentage of each ingredient in the braising broth is as follows: green tangerines 0.05%, black tea 0.5%, five-spice powder 0.5%, salt 4%, soy sauce 2%, MSG 2%, white sugar 8%. The weight ratio of braising broth to cracked eggs is 1.2:1.

[0053] (4) Vacuum cooling and dehydration: The boiled eggs are vacuum cooled and dehydrated to obtain dehydrated eggs; the vacuum degree of vacuum cooling and dehydration is -0.06MPa, and the vacuum cooling and dehydration time is 25min;

[0054] (5) Shelling and packaging: The shells of dehydrated eggs are removed by rotating an egg peeler and then vacuum-packed to obtain packaged eggs;

[0055] (6) High temperature sterilization: Sterilize the packaged eggs at 115℃ for 20 minutes to obtain tea eggs.

[0056] Example 2

[0057] An industrial processing method for traditional tea eggs includes the following steps:

[0058] (1) Baking and cooking: After washing the eggs, place them on a tray and put them in a steam oven. Bake the eggs at 50°C for 3 hours, then use steam to raise the temperature to 92°C and steam for 22 minutes to obtain cooked eggs.

[0059] (2) Low-frequency vibration to crack the shell: The cooked egg is vibrated at a low frequency in a linear vibrator to make the shell crack, thus obtaining a cracked egg; the amplitude of the low-frequency vibration is 3mm, the frequency is 15Hz, and the duration of the low-frequency vibration is 4s.

[0060] (3) Circulating high-temperature braising: Prepare braising broth with green tangerines, black tea, spices, salt, soy sauce, MSG, white sugar and water. Place cracked eggs in a special stacked steaming basket. Place the basket and braising broth in a braising broth tank (pressure vessel). After covering, heat the braising broth to 105℃ using a steam jacket and braise for 3 hours. During braising, the broth is circulated in the braising broth tank for 5 minutes every 15 minutes by a circulating broth pump to obtain braised eggs. The weight percentage of each ingredient in the braising broth is as follows: green tangerines 0.07%, black tea 1%, five-spice powder 1%, salt 3%, soy sauce 5%, MSG 1%, white sugar 5%. The weight ratio of braising broth to cracked eggs is 1.3:1.

[0061] (4) Vacuum cooling and dehydration: The boiled eggs are vacuum cooled and dehydrated to obtain dehydrated eggs; the vacuum degree of vacuum cooling and dehydration is -0.07MPa, and the vacuum cooling and dehydration time is 20min;

[0062] (5) Shelling and packaging: The shells of dehydrated eggs are removed by rotating an egg peeler and then vacuum-packed to obtain packaged eggs;

[0063] (6) High temperature sterilization: Sterilize the packaged eggs at 118℃ for 16 minutes to obtain tea eggs.

[0064] Example 3

[0065] An industrial processing method for traditional tea eggs includes the following steps:

[0066] (1) Baking and cooking: After washing the eggs, place them on a tray and put them in a steam oven. Bake the eggs at 60°C for 2 hours, then use steam to raise the temperature to 100°C and steam for 15 minutes to obtain cooked eggs.

[0067] (2) Low-frequency vibration to crack the shell: The cooked egg is vibrated at a low frequency in a linear vibrator to make the shell crack, thus obtaining a cracked egg; the amplitude of the low-frequency vibration is 4mm, the frequency is 20Hz, and the duration of the low-frequency vibration is 3s.

[0068] (3) Circulating high-temperature braising: Prepare braising broth with green tangerines, black tea, spices, salt, soy sauce, MSG, white sugar and water. Place cracked eggs in a special stacked steaming basket. Place the basket and braising broth in a braising broth tank (pressure vessel). After covering, heat the braising broth to 103℃ using a steam jacket and braise for 4 hours. During braising, the broth is circulated in the braising broth tank for 5 minutes every 15 minutes by a circulating broth pump to obtain braised eggs. The weight percentage of each ingredient in the braising broth is as follows: green tangerines 0.1%, black tea 2%, spices 2%, salt 2%, soy sauce 10%, MSG 0.5%, white sugar 1%. The weight ratio of braising broth to cracked eggs is 1.5:1.

[0069] (4) Vacuum cooling and dehydration: The boiled eggs are vacuum cooled and dehydrated to obtain dehydrated eggs; the vacuum degree of vacuum cooling and dehydration is -0.08MPa, and the vacuum cooling and dehydration time is 15min;

[0070] (5) Shelling and packaging: The shells of dehydrated eggs are removed by rotating an egg peeler and then vacuum-packed to obtain packaged eggs;

[0071] (6) High temperature sterilization: Sterilize the packaged eggs at 121℃ for 13 minutes to obtain tea eggs.

[0072] Compare with Example 1

[0073] The difference from Example 1 is that step (1) is not performed.

[0074] Compare with Example 2

[0075] The difference from Example 1 is that step (2) is not performed.

[0076] Compare with Example 3

[0077] The difference from Example 1 is that in step (3), the braising temperature of 102°C is replaced with a medium temperature of 95°C.

[0078] Compare with Example 4

[0079] The difference from Example 1 is that step (4) is not performed.

[0080] Compare with Example 5

[0081] The difference from Example 1 is that step (1) and step (6) are not performed.

[0082] Table 1 shows the test results of the tea eggs prepared in Examples 1-3 and Control Examples 1-5.

[0083] Table 1

[0084]

[0085] As shown in Table 1, all three examples exhibited a certain rate of weight loss after baking, with a significant decrease in egg white viscosity and a relatively high salt content, indicating that the tea eggs absorbed the flavor well. Comparing Example 1 and Control Example 1, it can be seen that without baking, the chewiness of the tea egg white significantly increased, and the salt content was relatively low, suggesting that baking significantly reduces the chewiness of the white and enhances the salt penetration during braising.

[0086] As can be seen from Example 1 and Comparative Example 2, the salt content in the egg white of tea leaves is significantly reduced when the shell is not broken by vibration before braising, indicating that not breaking the shell by vibration is not conducive to salt penetration.

[0087] As can be seen from Example 1 and Comparative Example 3, the salt content in the egg white of tea is significantly lower when medium-temperature braising is used, indicating that high-temperature braising is conducive to salt penetration.

[0088] As can be seen from Example 1 and Comparative Example 4, when vacuum cooling dehydration is cancelled, both chewiness and salt content decrease slightly, indicating that vacuum cooling treatment partially dehydrates the tea eggs, which is beneficial to increasing the salt content.

[0089] As can be seen from Example 1 and Comparative Example 5, there was no significant difference in the chewiness of the protein when baking and high-temperature sterilization were omitted. This indicates that baking can offset the increase in the chewiness of the protein caused by high-temperature sterilization, thus maintaining the chewiness of the tea egg before sterilization.

[0090] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. An industrial processing method for traditional tea eggs, characterized in that, Including the following steps: (1) Baking and cooking: Baking eggs, heating with steam, and steaming to obtain cooked eggs; the baking temperature is 40~60℃, the baking time is 2~4 h; the temperature is raised to 85~100℃, and the steaming time is 15~30 min. (2) Low-frequency vibration to crack the shell: The cooked egg is vibrated at a low frequency to make the shell crack, thus obtaining a cracked egg; (3) Circulating high-temperature braising: Prepare braising liquid with green tangerines, black tea, spices, salt, soy sauce, MSG, white sugar and water. Place the braising liquid and cracked eggs in a pressure vessel, heat the braising liquid to 102~105℃ and braise. Circulate the braising liquid during braising to obtain braised eggs. (4) Vacuum cooling and dehydration: Vacuum cooling and dehydration of the boiled eggs to obtain dehydrated eggs; (5) Shell removal and packaging: Remove the shells from the dehydrated eggs, vacuum pack them, and obtain packaged eggs; (6) High-temperature sterilization: Sterilize the packaged eggs to obtain tea eggs; The sterilization temperature is 115~121℃.

2. The industrial processing method according to claim 1, characterized in that, In step (2), the amplitude of the low-frequency vibration is 2~4 mm, the frequency is 10~20 Hz, and the duration of the low-frequency vibration is 3~6 s.

3. The industrial processing method according to claim 1, characterized in that, In step (3), the amount of each ingredient in the braising liquid is as follows, based on the weight percentage of water: 0.05~0.1% green tangerine, 0.5~2% black tea, 0.5~2% spices, 2~4% salt, 2~10% soy sauce, 0.5~2% MSG, and 1~8% white sugar.

4. The industrial processing method according to claim 1, characterized in that, In step (3), the weight ratio of brine to cracked eggs is 1~1.5:

1.

5. The industrial processing method according to claim 1, characterized in that, In step (3), the braising time is 3-5 hours; the braising liquid is circulated for 3-8 minutes every 10-20 minutes.

6. The industrial processing method according to claim 1, characterized in that, In step (4), the vacuum degree of vacuum dehydration is -0.06 to -0.08 MPa, and the vacuum dehydration time is 15 to 25 min.

7. The industrial processing method according to claim 1, characterized in that, In step (6), the sterilization time is 13~20 min.

8. Tea eggs produced by the industrial processing method according to any one of claims 1 to 7.

9. The application of the tea egg as described in claim 8 in the food industry.

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