A tea residue protein-based pickering emulsion gel, a preparation method thereof, a 3D printing method and application thereof

Abstract

This invention discloses a tea residue protein-based Pickering emulsion gel, its preparation method, 3D printing method, and applications, belonging to the field of food processing technology. The tea residue protein-based Pickering emulsion gel uses tea residue protein with added food colloids as the aqueous phase and olive oil as the oil phase. By mass fraction, the aqueous phase contains 3-5% tea residue protein, 1.5-2.5% food colloids, and the remainder is water; the oil phase contains 70-75% olive oil. First, the tea residue protein is enzymatically modified to obtain enzymatically modified tea residue protein. Then, food colloids are added to the enzymatically modified tea residue protein, followed by water bath, stirring, and cooling. Finally, olive oil is added, emulsified, and dispersed to obtain the tea residue protein-based Pickering emulsion gel. This emulsion gel closely resembles the appearance and taste of buttercream frosting, with a lower fat content, satisfying consumers' pursuit of healthy food. It is also unaffected by differences in cake decorator skills, improving cake decorating efficiency and enabling the production of cake decorations that meet specific needs.

Description

Technical Field

[0001] This invention belongs to the field of novel food processing technology, specifically relating to a tea residue protein-based Pickering emulsion gel, its preparation method, 3D printing method, and applications. Background Technology

[0002] Cream commonly used for piping comes in two types: animal-based cream and vegetable-based cream. Animal-based cream is made from milk fat extracted from fresh milk and then concentrated. Its main component is animal fat, which contains high levels of cholesterol and calories. Long-term consumption can easily lead to arteriosclerosis, heart disease, coronary heart disease, and obesity. Vegetable-based cream (also known as hydrogenated oil) is made by hydrogenating vegetable oil. The hydrogenation process converts the unsaturated fatty acids in vegetable oil into saturated or semi-saturated states. Studies have shown that trans fatty acids are produced during the hydrogenation process of vegetable oil, which may induce arteriosclerosis and increase the risk of heart disease and stroke. Therefore, excessive consumption of existing cream can be harmful to health. However, simply reducing the amount of fat can lead to problems with the palatability and processing performance of food. Therefore, there is a need for an alternative cream that can maintain the taste of cream while reducing its fat content. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a tea residue protein-based Pickering emulsion gel, its preparation method, 3D printing method and application, which solves the problem of high fat content in existing creams while maintaining the creamy texture.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] This invention discloses a tea residue protein-based Pickering emulsion gel, wherein the tea residue protein-based Pickering emulsion gel uses tea residue protein added to food colloids as the aqueous phase and olive oil as the oil phase;

[0006] Of these, by mass fraction, the aqueous phase contains 3-5% tea residue protein, 1.5-2.5% food colloids, and the remainder is water; the oil phase contains 70-75% olive oil.

[0007] Preferably, the tea residue protein is enzyme-modified tea residue protein.

[0008] More preferably, the enzyme is transglutaminase.

[0009] Preferably, the food colloid is xanthan gum, pectin, or carrageenan.

[0010] This invention also discloses a method for preparing the above-mentioned tea residue protein-based Pickering emulsion gel, wherein food colloids are added to tea residue protein, the mixture is subjected to a water bath, stirred and cooled, and then olive oil is added, emulsified and dispersed to obtain tea residue protein-based Pickering emulsion gel.

[0011] Preferably, the preparation method of the tea residue protein is as follows: take tea leaves and tea residue, grind them to obtain tea residue powder; then add the tea residue powder to a NaOH solution with a material-to-liquid ratio of 1:30, stir, centrifuge, take the supernatant, decolorize, adjust the pH value to 3.5, centrifuge to obtain precipitate, wash the precipitate to neutral, freeze dry, and obtain tea residue protein.

[0012] More preferably, the water bath and stirring conditions are: stirring in a water bath at 85 ℃ for 1 h; the emulsification conditions are: homogenizing and emulsifying with a high-speed shear machine at 11000-15000 rpm for 3-5 min.

[0013] This invention also discloses a 3D printing method for tea residue protein-based Pickering emulsion gel, with a nozzle diameter of 0.60 mm, 0.84 mm, or 1.0 mm, a printing distance of 1.5–2.5 mm, a printing temperature of 25–30 °C, a nozzle movement speed of 25–30 mm / s, and a material output speed of 0.003–0.005 cm. 3 Under the condition of / s, the above-mentioned tea residue protein-based Pickering emulsion gel was 3D printed.

[0014] This invention also discloses the application of a tea residue protein-based Pickering emulsion gel in cake decorating.

[0015] Preferably, the above-mentioned tea residue protein-based Pickering emulsion gel is used to prepare cake decorations via 3D printing.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This invention provides a tea residue protein-based Pickering emulsion gel. The tea residue protein-based Pickering emulsion gel uses enzyme-modified tea residue protein as its main component. Firstly, tea residue protein can be sourced from waste tea residue in beverage factories, reducing resource waste and saving processing costs. Secondly, it avoids the risks associated with excessive use of traditional surfactants. Thirdly, using tea residue protein as the main component ensures food safety, and the resulting emulsion gel has a texture similar to butter. Adding food colloids as the aqueous phase improves the rheological properties of the tea residue protein Pickering emulsion. Using olive oil as the oil phase satisfies the desired emulsion gel texture while effectively reducing the fatty acid content in the substitute butter (i.e., the tea residue protein Pickering emulsion) without affecting the content of other nutrients. By simultaneously loading the aqueous and oil phases through physical cross-linking, the resulting tea residue protein-based Pickering emulsion gel can regulate lipid digestion and absorption, has a long stability period, and low fat content. The viscosity as a function of shear rate test results showed that the viscosity of the tea residue protein-based Pickering emulsion gel was similar to that of commercially available butter, and the texture was also similar. The sensory evaluation results showed that the taste of the tea residue protein-based Pickering emulsion gel was similar to that of commercially available butter. The optical imaging results showed that the color and shape of the tea residue protein-based Pickering emulsion gel were similar to those of commercially available butter, and it was not easy to collapse, making it suitable for 3D printing. This indicates that the tea residue protein-based Pickering emulsion gel can be used as a butter decoration on the surface of cakes, bread, cookies and other foods.

[0018] Furthermore, by using transglutaminase to modify tea residue protein, intramolecular and intermolecular covalent cross-linking of protein peptides can be catalyzed, thereby improving the structure and function of the protein. This further enhances the foaming properties, emulsifying properties, emulsification stability, thermal stability, water retention, and gelling ability of the obtained tea residue protein, thereby improving the flavor, taste, texture, and appearance of the food.

[0019] This invention provides a method for preparing a tea residue protein-based Pickering emulsion gel. By using tea residue protein as the main component, it can overcome the resource waste problem caused by the large amount of tea residue discarded after the production of tea beverages in large beverage factories. While making full use of tea resources, a stable emulsion gel can be obtained simply by shearing with a high-speed emulsifier. Compared with the high-pressure homogenization method, it saves manufacturing costs and time costs.

[0020] Furthermore, in the preparation of tea residue protein, the protein in the tea residue is dissolved in NaOH solution. This process not only separates and removes the insoluble parts of the tea residue protein, but also allows the NaOH solution to hydrolyze and ionize in water to produce Na+. + and OH -None of these will affect the system. Adjusting the pH of the liquid to 3.5, which is consistent with the isoelectric point of tea residue protein, ensures complete protein precipitation, prevents waste, and improves extraction efficiency.

[0021] This invention provides a 3D printing method for tea residue protein-based Pickering emulsion gel. By adding edible colloids to the tea residue protein-based Pickering emulsion gel, its viscoelasticity is enhanced and it possesses a certain degree of self-support. This overcomes the safety risks associated with excessive use of surfactants due to increasing the volume fraction of the internal phase of the emulsion, as well as the potential environmental pollution problems during surfactant preparation. By adjusting different printing parameters, such as printing distance, nozzle diameter, printing temperature, nozzle movement speed, and discharge speed, optimal printing conditions are achieved, resulting in high-precision printed piping buttercream. This provides a reference for other researchers to achieve precise piping printing. This method overcomes the shortcomings of existing manual piping techniques using piping nozzles and other tools, which are characterized by low efficiency and high dependence on the piping skill of the piping artist. The accuracy of 3D printed piping buttercream can reach over 95%, and it does not collapse within 1-2 days after printing. Attached Figure Description

[0022] Figure 1 The viscosity of the tea residue protein-based Pickering emulsion gel (pH 7, tea residue protein crude extract particle concentration 3%, xanthan gum content 1.5%, 2.0% and 2.5% respectively) of the present invention is shown as a function of shear rate.

[0023] Figure 2 The graph shows the viscosity of three commercially available creams as a function of shear rate.

[0024] Figure 3 The rheological properties of the tea residue protein-based Pickering emulsion gel of the present invention (pH value of 7, concentration of crude tea residue protein particles of 3%, and xanthan gum content of 1.5%, 2.0% and 2.5%, respectively) are shown in Figure A; where A is the curve of elastic modulus as a function of angular velocity and B is the curve of viscous modulus as a function of angular velocity.

[0025] Figure 4 The images show the results of 3D printing hollow cylinders using tea residue protein-based Pickering emulsion gel (pH 7, tea residue protein crude extract particle concentration 3%, xanthan gum content 1.5%, 2.0%, and 2.5%, respectively) as raw material; including the effect view (A1: 1.5%; B1: 2.0%; C1: 2.5%), top view (A2: 1.5%; B2: 2.0%; C2: 2.5%), and front view (A3: 1.5%; B3: 2.0%; C3: 2.5%).

[0026] Figure 5 The images show the 3D printing effect of the tea residue protein-based Pickering emulsion gel (pH 7, tea residue protein crude extract particle concentration 3%, xanthan gum content 1.5%, 2.0%, and 2.5%) on food. Among them, A is a castle printed on bread, B is a four-leaf clover pattern printed on bread, C is a corridor printed on bread, D is a star printed on cake, and E is a star printed on biscuits. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings:

[0030] This invention provides a tea residue protein-based Pickering emulsion gel, wherein the tea residue protein-based Pickering emulsion gel uses modified tea residue protein added to food colloids as the aqueous phase and olive oil as the oil phase;

[0031] Of these, by mass fraction, the aqueous phase contains 3-5% tea residue protein, 1.5-2.5% food colloids, and the remainder is water; the oil phase contains 70-75% olive oil.

[0032] The present invention provides a method for preparing a tea residue protein-based Pickering emulsion gel, the steps of which are as follows:

[0033] (1) Preparation of tea residue: Take tea leaves and soak them in boiling water at a ratio of 1:50. Collect the tea residue with filter cloth, repeat the process several times, and dry them with hot air at 65 ℃ for 2-3 days. Grind them with a high-speed grinder and pass them through a 180 μm sieve. The powder yield is 50.6%.

[0034] (2) Preparation of crude tea residue protein extract particles: Tea residue powder was added to a 0.3 M NaOH solution with a material-to-liquid ratio of 1:30 and stirred intermittently at 90 °C for 1.5–2 h. The mixture was then centrifuged at 8000–10000 rpm for 20–30 min, and the supernatant was collected. 30% H₂O₂ was added for decolorization for 24–36 h. The pH of the liquid was adjusted to 3.5, and the mixture was allowed to stand for 30–60 min. It was then centrifuged at 8000–10000 rpm for 20–30 min. The resulting precipitate was washed until neutral, and then freeze-dried in a freeze dryer at a cold well temperature of -55 °C and a vacuum degree of 8–15 for 48 h. The resulting particles were the crude tea residue protein extract particles, with an extraction rate of 26.25%.

[0035] (3) Enzyme modification: Based on the aqueous phase, accurately weigh 3-5% of crude tea residue protein extract particles into deionized water, add 0.3% glutamine transaminase, and incubate in a water bath at 40-45 ℃ for 4-5 h.

[0036] (4) Adding colloids: Based on the aqueous phase, add 1.5-2.5% by mass of food colloids, stir in an 85°C water bath for 1 h, and cool to room temperature in an ice bath to obtain the aqueous phase;

[0037] Among them, the food colloid is xanthan gum, pectin or carrageenan. The addition of food colloid can adjust and regulate the rheological properties of Pickering emulsion, such as elastic modulus and viscous modulus, so that it has both good viscosity and formability, as well as good shape retention (i.e. mechanical strength), so that the printed object can be well formed and maintain complex printed structure.

[0038] (5) Preparation of tea residue protein-based Pickering emulsion gel: Using olive oil as the oil phase, add 70-75% olive oil to the aqueous phase based on the total volume, and homogenize and emulsify using a high-speed shear machine at 11000-15000 rpm for 3-5 min. After dispersion, tea residue protein-based Pickering emulsion gel is obtained.

[0039] Because tea residue protein-based Pickering emulsion gel is a kinetically stable system composed of two immiscible phases, it has strong fluidity and exhibits a fluid state, thus lacking plasticity and generally unsuitable as a 3D printing material. This invention provides a 3D printing method for tea residue protein-based Pickering emulsion gel, with nozzle diameters of 0.60 mm, 0.84 mm, or 1.0 mm, a printing distance of 1.5–2.5 mm, a printing temperature of 25–30 °C, a nozzle movement speed of 25–30 mm / s, and an output velocity of 0.003–0.005 cm⁻¹. 3 3D printing of tea residue protein-based Pickering emulsion gel under conditions of / s.

[0040] The specific steps are as follows:

[0041] (1) Determination of nozzle diameter: Generally, the larger the nozzle diameter, the easier the material output and the less likely the strip breakage will occur. However, due to the thicker output lines, the surface of the printed object is relatively rough, resulting in poor printing accuracy. The smaller the nozzle diameter, the finer the output lines, the smoother the surface of the printed object, and the higher the accuracy. However, when the nozzle diameter is small, the material output is difficult and the strip breakage is likely to occur. Therefore, the forming characteristics of printed objects with nozzle diameters of 0.60 mm, 0.84 mm, and 1.0 mm were studied in the experiment. When the nozzle diameter is 0.84 mm, the continuity of the output can be well guaranteed, and relatively accurate printing can be achieved.

[0042] (2) Determination of printing distance: The distance between the printhead and the printing platform significantly affects printing accuracy. Excessive printing distance can cause the extruded material strip to not fully adhere to the printing platform or the printed portion, resulting in a dragging effect and poor printing accuracy. Insufficient printing distance can cause the printhead to compress the printed material, deforming the printed object and greatly reducing printing accuracy. Under the optimal printhead diameter of 0.84 mm, the influence of different printing distances on printing characteristics was studied, and it was determined that a printing distance of 1.5~2.5 mm can achieve a printing accuracy of over 95%.

[0043] (3) Determination of printing temperature: Experiments showed that temperature had little effect on Pickering emulsion gel, and the printing temperature was 25 ℃~30 ℃. Further, through experiments, the appropriate printing temperature was determined to be 25 ℃.

[0044] (4) Nozzle travel speed: The nozzle travel speed also significantly affects printing accuracy. When the travel speed is too high, the extruded material strip will move with the nozzle before it is fully attached to the printing platform or the printed part, which will significantly affect the printing accuracy. When the nozzle travel speed is low, the extruded material strip will be twisted, making the printed object wider and larger, resulting in lower accuracy. After a large number of experiments, it was determined that the best printing accuracy is achieved when the nozzle travel speed is 25~30 mm / s.

[0045] (5) Output speed: The extrusion speed of the material and the moving speed of the nozzle should be well combined. A faster material extrusion speed will cause the printed object to be wider and larger than the target object, while a lower output speed will cause the material to break easily. Therefore, the optimal output speed was determined to be 0.003~0.005 cm. 3 / s.

[0046] The nozzle movement speed and the material output speed both significantly affect the printing accuracy. Appropriate material extrusion speed and nozzle movement speed can greatly improve printing accuracy.

[0047] Example 1

[0048] A tea residue protein-based Pickering emulsion gel with added xanthan gum, using enzyme-modified tea residue protein with added xanthan gum (purchased from Qingdao Yousuo Chemical Technology Co., Ltd.) as the aqueous phase and olive oil (purchased from Yihai Kerry Food Marketing Co., Ltd., with a monounsaturated fatty acid content >75%) as the oil phase;

[0049] Of these, by mass fraction, tea residue contains 5% protein, 1.5% xanthan gum, and 75% olive oil.

[0050] The preparation method of the above-mentioned tea residue protein-based Pickering emulsion gel with added xanthan gum involves: green tea leaves are steeped in boiling water at a material-to-liquid ratio of 1:50 for 15 min; tea residue is collected using a filter cloth; this process is repeated 5 times; the residue is dried in hot air at 65 ℃ for 2 days; then ground using a high-speed grinder and passed through a 180 μm sieve. The tea residue powder is added to a 0.3M NaOH solution at a material-to-liquid ratio of 1:30 and stirred intermittently at 90 ℃ for 2 h; centrifuged at 8000 rpm for 30 min; the supernatant is collected; 30% H2O2 is added for decolorization for 24 h; the pH of the liquid is adjusted to 3.5; the mixture is allowed to stand for 60 min; centrifuged at 8000 rpm for 30 min; the resulting precipitate is washed until neutral; the precipitate is placed in a freeze dryer and freeze-dried at a cold well temperature of -55 ℃ and a vacuum degree of 8 for 48 h. 1.25 g of crude tea residue protein extract particles are accurately weighed into 25 mL of deionized water. Add 0.075 g of transglutaminase and incubate at 45 ℃ for 4 h. Accurately weigh 0.375 g of xanthan gum and add it to the crude tea residue protein extract. Stir at 85 ℃ for 1 h to fully dissolve the extract, thereby improving the rheological properties and corresponding gel-forming characteristics of the emulsion gel. Cool to room temperature in an ice bath to obtain the aqueous phase. Add 75 mL of olive oil to the aqueous phase and homogenize and emulsify at 15000 rpm for 3 min using a high-speed shear mixer. After dispersion, obtain the tea residue protein-based Pickering emulsion gel.

[0051] The above-mentioned 3D printing method for tea residue protein-based Pickering emulsion gel with added xanthan gum was performed at a nozzle diameter of 0.84 mm, a printing distance of 1.5 mm, a printing temperature of 25 ℃, a nozzle movement speed of 30 mm / s, and a material output speed of 0.003 cm. 3 Under the condition of / s, 3D printing of decorative patterns can achieve an accuracy of 99% and the printed patterns will not collapse within 48 hours after printing.

[0052] Example 2

[0053] A tea residue protein-based Pickering emulsion gel with added xanthan gum, using enzyme-modified tea residue protein with added xanthan gum (purchased from Qingdao Yousuo Chemical Technology Co., Ltd.) as the aqueous phase and olive oil (purchased from Yihai Kerry Food Marketing Co., Ltd., with a monounsaturated fatty acid content >75%) as the oil phase;

[0054] Of these, by mass fraction, tea residue contains 4% protein, 2.0% xanthan gum, and 74% olive oil.

[0055] The preparation method of the above-mentioned tea residue protein-based Pickering emulsion gel with added xanthan gum involves: green tea leaves are steeped in boiling water at a material-to-liquid ratio of 1:50 for 15 min; tea residue is collected using a filter cloth; this process is repeated 5 times; the residue is dried in hot air at 65 ℃ for 2 days; then ground using a high-speed grinder and passed through a 180 μm sieve. The tea residue powder is added to a 0.3 M NaOH solution at a material-to-liquid ratio of 1:30 and stirred intermittently at 90 ℃ for 1.7 h; centrifuged at 8000 rpm for 25 min; the supernatant is collected; 30% H2O2 is added for decolorization for 28 h; the pH of the liquid is adjusted to 3.5; the mixture is allowed to stand for 60 min; centrifuged at 8000 rpm for 30 min; the resulting precipitate is washed until neutral; the precipitate is placed in a freeze dryer and freeze-dried at a cold well temperature of -55 ℃ and a vacuum degree of 13 for 48 h. 1.04 g of crude tea residue protein extract particles are accurately weighed into 26 mL of deionized water. Add 0.078 g of transglutaminase and incubate at 45 ℃ for 4 h. Accurately weigh 0.52 g of xanthan gum and add it to the crude extract of tea residue protein. Stir at 85 ℃ for 1 h to fully dissolve the extract, thereby improving the rheological properties and corresponding gel-forming characteristics of the emulsion gel. Cool to room temperature in an ice bath to obtain the aqueous phase. Add 74 mL of olive oil to the aqueous phase and homogenize and emulsify at 15000 rpm for 3 min using a high-speed shear mixer. After dispersion, obtain the tea residue protein-based Pickering emulsion gel.

[0056] The above-mentioned 3D printing method for tea residue protein-based Pickering emulsion gel with added xanthan gum was performed at a nozzle diameter of 0.84 mm, a printing distance of 1.5 mm, a printing temperature of 25 ℃, a nozzle movement speed of 30 mm / s, and a material output speed of 0.003 cm. 3 Under the condition of / s, 3D printing of decorative patterns can achieve an accuracy of 99% and the printed patterns will not collapse within 48 hours after printing.

[0057] Example 3

[0058] A tea residue protein-based Pickering emulsion gel with added xanthan gum, using enzyme-modified tea residue protein with added xanthan gum (purchased from Qingdao Yousuo Chemical Technology Co., Ltd.) as the aqueous phase and olive oil (purchased from Yihai Kerry Food Marketing Co., Ltd., with a monounsaturated fatty acid content >75%) as the oil phase;

[0059] Of these, by mass fraction, tea residue contains 3% protein, 2.5% xanthan gum, and 73% olive oil.

[0060] The preparation method of the above-mentioned tea residue protein-based Pickering emulsion gel with added xanthan gum involves: green tea leaves are steeped in boiling water at a material-to-liquid ratio of 1:50 for 15 min; tea residue is collected using a filter cloth; this process is repeated 5 times; the residue is then dried in hot air at 65 ℃ for 3 days, ground using a high-speed grinder, and passed through a 180 μm sieve. The tea residue powder is added to a 0.3 M NaOH solution at a material-to-liquid ratio of 1:30 and intermittently stirred at 90 ℃ for 2 h, centrifuged at 9000 rpm for 30 min, and the supernatant is collected. 30% H2O2 is added for decolorization for 24 h; the pH of the liquid is adjusted to 3.5, allowed to stand for 45 min, and centrifuged at 8000 rpm for 30 min. The resulting precipitate is washed until neutral, and then freeze-dried in a freeze dryer at a cold well temperature of -55 ℃ and a vacuum degree of 9 for 48 h. 0.81 g of the crude tea residue protein extract particles are accurately weighed into 27 mL of deionized water. Add 0.081 g of transglutaminase and incubate at 45 ℃ for 4.5 h. Accurately weigh 0.675 g of xanthan gum and add it to the crude extract of tea residue protein. Stir at 85 ℃ for 1 h to fully dissolve the extract, thereby improving the rheological properties and corresponding gel-forming characteristics of the emulsion gel. Cool to room temperature in an ice bath to obtain the aqueous phase. Add 73 mL of olive oil to the aqueous phase and homogenize and emulsify at 13000 rpm for 3 min using a high-speed shear mixer. After dispersion, obtain the tea residue protein-based Pickering emulsion gel.

[0061] The above-mentioned 3D printing method for tea residue protein-based Pickering emulsion gel with added xanthan gum was performed at a nozzle diameter of 0.84 mm, a printing distance of 1.5 mm, a printing temperature of 25 ℃, a nozzle movement speed of 30 mm / s, and a material output speed of 0.003 cm. 3 Under the condition of / s, 3D printing of decorative patterns can achieve an accuracy of 99% and the printed patterns will not collapse within 48 hours after printing.

[0062] Example 4

[0063] A tea residue protein-based Pickering emulsion gel with added pectin, using enzyme-modified tea residue protein with added pectin as the aqueous phase and olive oil as the oil phase;

[0064] The tea residue contained 5% protein by mass fraction, 2.5% pectin (purchased from Qingdao Yousuo Chemical Technology Co., Ltd.), and 75% olive oil (purchased from Yihai Kerry Food Marketing Co., Ltd., with a monounsaturated fatty acid content >75%).

[0065] The above-mentioned method for preparing pectin-added tea residue protein-based Pickering emulsion gel involves extracting green tea in boiling water at a ratio of 1:50 for 15 min, collecting the tea residue with a filter cloth, repeating the above process 5 times, and drying it with hot air at 65 ℃ for 2 days. The residue is then ground using a high-speed grinder and passed through a 180 μm sieve. The tea residue powder is added to a 0.3 M NaOH solution at a ratio of 1:30 and intermittently stirred at 90 ℃ for 2 h, centrifuged at 8000 rpm for 30 min, and the supernatant is collected. 30% H2O2 is added for decolorization for 35 h; the pH of the liquid is adjusted to 3.5, allowed to stand for 60 min, and centrifuged at 8000 rpm for 30 min. The resulting precipitate is washed until neutral, and then freeze-dried in a freeze dryer at a cold well temperature of -55 ℃ and a vacuum degree of 10 for 48 h. 1.25 g of crude tea residue protein extract particles are accurately weighed into 25 mL of deionized water. Add 0.075 g of transglutaminase and incubate in a water bath at 40 ℃ for 4.5 h. Accurately weigh 0.625 g of pectin and add it to the protein solution, then stir in a water bath at 85 ℃ for 1 h to ensure complete dissolution, thus improving the rheological properties and corresponding gel-forming characteristics of the emulsion gel. Cool to room temperature in an ice bath to obtain the aqueous phase. Add 75 mL of olive oil to the aqueous phase and homogenize and emulsify using a high-speed shear mixer at 15000 rpm for 3 min. After dispersion, obtain a tea residue protein-based Pickering emulsion gel.

[0066] The above-mentioned 3D printing method for tea residue protein-based Pickering emulsion gel with added pectin was performed with a nozzle diameter of 1.0 mm, a printing distance of 2.0 mm, a printing temperature of 28 ℃, a nozzle movement speed of 25 mm / s, and a material output speed of 0.004 cm. 3 Under the condition of / s, 3D printing of decorative patterns can achieve an accuracy of 99% and the printed patterns will not collapse within 48 hours after printing.

[0067] Example 5

[0068] A tea residue protein-based Pickering emulsion gel with added carrageenan, using enzyme-modified tea residue protein with added carrageenan as the aqueous phase and olive oil as the oil phase;

[0069] Of these, by mass fraction, the tea residue protein content was 5%, the carrageenan (purchased from Qingdao Yousuo Chemical Technology Co., Ltd.) content was 2.0%, and the olive oil (purchased from Yihai Kerry Food Marketing Co., Ltd., whose monounsaturated fatty acid content was >75%) content was 70%.

[0070] The above-mentioned method for preparing tea residue protein-based Pickering emulsion gel with added carrageenan involves extracting green tea in boiling water at a ratio of 1:50 for 15 min, collecting the tea residue with a filter cloth, repeating the above process 5 times, and drying it with hot air at 65 ℃ for 3 days. The residue is then ground using a high-speed grinder and passed through a 180 μm sieve. The tea residue powder is added to a 0.3M NaOH solution at a ratio of 1:30 and intermittently stirred at 90 ℃ for 1.5 h, centrifuged at 10000 rpm for 20 min, and the supernatant is collected. 30% H2O2 is added for decolorization for 36 h; the pH of the liquid is adjusted to 3.5, allowed to stand for 30 min, and centrifuged at 10000 rpm for 20 min. The resulting precipitate is washed until neutral, and then freeze-dried in a freeze dryer at a cold well temperature of -55 ℃ and a vacuum degree of 15 for 48 h. 1.5 g of crude tea residue protein extract particles are accurately weighed into 30 mL of deionized water. Add 0.09 g of transglutaminase and incubate in a 43 ℃ water bath for 5 h. Accurately weigh 0.6 g of carrageenan and add it to the protein solution, stirring in an 85 ℃ water bath for 1 h to ensure complete dissolution, thus improving the rheological properties and corresponding gel-forming characteristics of the emulsion gel. Cool to room temperature in an ice bath to obtain the aqueous phase. Add 70 mL of olive oil to the aqueous phase and homogenize and emulsify using a high-speed shear mixer at 11000 rpm for 5 min. After dispersion, obtain a tea residue protein-based Pickering emulsion gel.

[0071] The above-mentioned 3D printing method for tea residue protein-based Pickering emulsion gel with added carrageenan was performed at a nozzle diameter of 0.60 mm, a printing distance of 2.5 mm, a printing temperature of 30 ℃, a nozzle movement speed of 30 mm / s, and a material output speed of 0.005 cm. 3 Under the condition of / s, 3D printing of decorative patterns can achieve an accuracy of 99% and the printed patterns will not collapse within 48 hours after printing.

[0072] The performance of the tea residue protein-based Pickering emulsion gel prepared in this invention was evaluated, and the results are as follows:

[0073] Shear-thinning properties are ideal for material systems used in 3D printing. The viscosity of the tea residue protein-based Pickering emulsion gels prepared in Examples 1-3 was tested as a function of shear rate. Figure 1 As shown, all Pickering emulsion gel formulations exhibited shear-thinning properties, and their viscosity increased gradient with increasing edible colloid content. Viscosity measurements were performed using commercially available animal cream (Anchor, New Zealand), vegetable cream (Vitamin B, China), and finished cream (President, France). The results are shown below. Figure 2The tea residue protein-based Pickering emulsion gels prepared in Examples 1-3 were compared with commercially available butter. It was found that the three commercially available butters also exhibited similar shear-thinning characteristics to the Pickering emulsion gel. Moreover, the viscosity of the vegetable butter and the tea residue protein-based Pickering emulsion gel were similar, and their tactile feel was similar. This indicates that the prepared tea residue protein-based Pickering emulsion gel has a similar tactile feel to commercially available butter.

[0074] Sensory evaluations were conducted on commercially available animal cream (Anchor, New Zealand), vegetable cream (Vitamin B, China), finished cream (President, France), and the tea residue protein-based Pickering emulsion gel prepared in Examples 1-3. The evaluation items for sensory evaluation mainly included taste and aroma. The specific sensory evaluation results are shown in Table 1:

[0075] Table 1. Sensory evaluation results of commercially available butter and tea dregs protein-based Pickering emulsion gels.

[0076]

[0077] As can be seen from Table 1, the tea residue protein-based Pickering emulsion gels prepared in Examples 1-3 have a similar taste to commercially available cream.

[0078] The rheological properties of the tea residue protein-based Pickering emulsion gels prepared in Examples 1-3 were tested, and the results are shown in the figure. Figure 3 As the angular velocity increases, both the elastic modulus and the viscous modulus of Pickering emulsion gel increase. Taking an angular velocity of 10 rad / s as an example, as the food colloid content increases from 1.5% to 2.5%, the elastic modulus increases from 1676 Pa to 3024 Pa, and the viscous modulus increases from 201.1 Pa to 354.5 Pa.

[0079] The tea residue protein-based Pickering emulsion gels prepared in Examples 1-3 were used to 3D print hollow cylinders and decorative patterns on food. Optical imaging results are shown below. Figure 4 and Figure 5 As can be seen from the hollow cylinder and piping model in the figure, the prepared tea residue protein-based Pickering emulsion gel with a three-dimensional structure has a complete structure, similar in color and shape to commercially available butter, and does not show obvious collapse phenomenon, indicating that the emulsion can be directly used as a piping material to print three-dimensional products.

[0080] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A tea residue protein-based Pickering emulsion gel, characterized in that, The tea residue protein-based Pickering emulsion gel uses tea residue protein-added food colloid as the aqueous phase and olive oil as the oil phase. Of which, by mass fraction, the aqueous phase contains 3%–5% tea residue protein, 1.5%–2.5% food colloids, and the remainder is water; the oil phase contains 70%–75% olive oil; the tea residue protein is tea residue protein modified with transglutaminase; and the food colloids are xanthan gum, pectin, or carrageenan.

2. The method for preparing a tea residue protein-based Pickering emulsion gel according to claim 1, characterized in that, Food colloids were added to tea residue protein, and the mixture was subjected to water bath, stirring and cooling. Olive oil was then added, and the mixture was emulsified and dispersed to obtain tea residue protein-based Pickering emulsion gel.

3. The method for preparing a tea residue protein-based Pickering emulsion gel as described in claim 2, characterized in that, The conditions for water bath and stirring were: stirring in a water bath at 85℃ for 1 h; the conditions for emulsification were: homogenizing and emulsifying at 11000-15000 rpm using a high-speed shear machine for 3-5 min.

4. A 3D printing method for tea residue protein-based Pickering emulsion gel, characterized in that, With a printhead diameter of 0.60 mm, 0.84 mm, or 1.0 mm, a printing distance of 1.5–2.5 mm, a printing temperature of 25–30°C, a printhead movement speed of 25–30 mm / s, and a discharge speed of 0.003–0.005 cm, the following parameters are specified: printhead diameter, printing distance, printing temperature, printhead movement speed, and discharge speed. 3 Under the condition of / s, 3D printing of the tea residue protein-based Pickering emulsion gel according to claim 1.

5. The application of the tea residue protein-based Pickering emulsion gel according to claim 1 in cake decorating.

6. The application as described in claim 5, characterized in that, Cake decorating was prepared by 3D printing using the tea residue protein-based Pickering emulsion gel described in claim 1.

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