Emulsion gel fat with stable protein-nanocrystal as well as preparation method and application of emulsion gel fat

Abstract

The invention discloses a protein-nanocrystal stable emulsion gel fat and a preparation method and application thereof, and the preparation method comprises the following steps: providing an isolated protein solution and fully hydrating the isolated protein solution; providing a nanocrystalline solution; mixing the isolated protein solution and the nanocrystalline solution, and adjusting the pH value of the system to 3-9 to prepare a protein-nanocrystalline compound dispersion liquid; and mixing an oil phase with the protein-nanocrystalline compound dispersion liquid, and performing high-speed shearing and homogenizing to obtain the emulsion gel fat. The interaction and emulsibility of the protein and the nanocrystals are adjusted by changing the pH value, a compound formed by the protein and the nanocrystals is used as an emulsifier for structuring the edible oil, and the prepared emulsion gel has good viscoelasticity and structure recovery capacity and can be used as a fat simulant for partially or completely replacing traditional plastic fat.

Description

Technical Field

[0001] The invention belongs to the technical field of oil processing, and in particular relates to a protein-nano crystal stabilized emulsion gel fat and a preparation method and application thereof. Background Art

[0002] As a form of structured oil, emulsion gel has attracted great attention in many fields such as food, medicine and chemical industry due to its excellent stability, morphology adjustability and biocompatibility. Animal fats or tropical plant fats commonly used in the food industry will produce a large amount of saturated fatty acids and even trans fatty acids during processing. Excessive intake of saturated fatty acids or trans fatty acids can harm human health. Emulsion gel is a semi-solid dispersion that combines the properties of emulsion and gel. It can be used as a fat substitute to reduce the saturated fat content in food.

[0003] The preparation of emulsion gels usually requires the addition of emulsifiers to maintain the stability of the system. Currently, most emulsifiers required by the food industry are small molecule surfactants, but because such surfactants may have negative effects on organisms, their types and amounts are strictly restricted. In order to build a safer emulsion system, it is necessary to replace traditional emulsifiers with natural food ingredients. Some amphiphilic biopolymers, such as polysaccharides, proteins, or protein-polysaccharide complexes, also have surface activity and have significant advantages such as low toxicity, good biocompatibility, easy availability, high nutritional value, and recognition in the food field.

[0004] 3D printing is widely used in the food industry, and can produce novel foods with customized shapes, flavors, and textures according to consumers' personal preferences and different nutritional needs. At present, emulsion gels have certain limitations as 3D printing inks. Their poor mechanical strength, weak structural recovery ability, and self-support make them prone to poor stacking during the printing process. Therefore, the development of emulsion gels for food 3D printing to replace fat has broadened the application range of fat simulants. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] One of the purposes of the present invention is to provide a protein-nanocrystal stabilized emulsion gel fat, which is prepared by adjusting the interaction and emulsification of protein and nanocrystals by changing the pH, and using the complex formed by protein and nanocrystals as an emulsifier to structure the edible oil, so that the emulsion gel has good viscoelasticity and structural recovery ability.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing a protein-nanocrystal stabilized emulsion gel fat, comprising:

[0009] Providing a protein isolate solution and fully hydrating it;

[0010] providing a nanocrystal solution;

[0011] The separated protein solution and the nanocrystal solution are mixed, and the pH of the system is adjusted to 3-9 to prepare a protein-nanocrystal complex dispersion;

[0012] The oil phase is mixed with the protein-nano crystal complex dispersion, and high-speed shearing and homogenization are performed to obtain an emulsion gel-like fat.

[0013] As a preferred embodiment of the method for preparing the protein-nanocrystal stabilized emulsion gel fat of the present invention, the isolated protein comprises one of pea protein isolate, soy protein isolate, broad bean protein isolate, mung bean protein isolate, oat protein isolate, quinoa protein isolate and peanut protein isolate.

[0014] As a preferred solution of the method for preparing the protein-nanocrystal stabilized emulsion gel fat of the present invention, the mass concentration of the isolated protein solution is 1-5%.

[0015] As a preferred embodiment of the method for preparing the protein-nanocrystal stabilized emulsion gel fat of the present invention, the hydration condition of the isolated protein solution is refrigeration at 1 to 10° C. for 6 to 12 hours.

[0016] As a preferred embodiment of the method for preparing the protein-nanocrystal stabilized emulsion gel fat of the present invention, the nanocrystals include one or more of cellulose nanocrystals derived from cotton, wood pulp, algae, bacteria or microcrystalline cellulose, starch nanocrystals or chitin nanocrystals.

[0017] As a preferred embodiment of the method for preparing the protein-nanocrystal stabilized emulsion gel fat of the present invention, the mass ratio of the protein to the nanocrystal is 1:1 to 5:1, and the mass concentration of the protein-nanocrystal complex in the aqueous phase is 1 to 5%.

[0018] As a preferred embodiment of the method for preparing the protein-nanocrystal stabilized emulsion gel fat of the present invention, the oil phase comprises liquid edible oil, including one or more of soybean oil, rapeseed oil, peanut oil, corn oil, sesame oil, sunflower oil, wheat germ oil, rice bran oil, almond oil, olive oil, and palm oil; the mass percentage of the oil phase is 60-75%.

[0019] As a preferred embodiment of the method for preparing the protein-nanocrystal stabilized emulsion gel fat of the present invention, the high-speed shear homogenization is carried out at 8000-15000 rpm for 1-3 minutes.

[0020] Another object of the present invention is to provide a protein-nanocrystal stabilized emulsion gel fat obtained by any of the preparation methods described above.

[0021] Another object of the present invention is to provide an application of the protein-nanocrystal stabilized emulsion gel fat as described above in 3D printing; specifically, an application in printing small-area single-layer structure models; and / or an application in printing planar stacked models and complex models.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention structures edible oil by changing the pH to adjust the interaction and emulsification of protein and nanocrystals, and uses the complex formed by protein and nanocrystals as an emulsifier. The prepared emulsion gel has good viscoelasticity and structural recovery ability, and can be used as a fat mimetic to partially or completely replace traditional plastic fat. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0025] Figure 1 Laser confocal microscopy images of the emulsion gel fat prepared in Examples 1 to 3.

[0026] Figure 2 Schematic diagram of the mechanism of the emulsion gel fat prepared in Examples 1 to 3 at pH values ​​of 3.0, 4.5 and 8.0.

[0027] Figure 3 These are optical microscope images of the emulsion gel fats prepared in Examples 1 to 9.

[0028] Figure 4Rheological properties of the emulsion gel fats prepared in Examples 1 to 9; wherein (a) is a strain sweep, (b) is a frequency sweep, and (c) is a time sweep.

[0029] Figure 5 This is a macroscopic image of the emulsion gel fat prepared in Examples 1 to 9.

[0030] Figure 6 The 3D printed physical pictures of Examples 4, 5, 7, 8 and 9 under three models are shown.

[0031] Figure 7 This is a macroscopic picture of the emulsion gel fat prepared in Comparative Examples 1 to 9. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0035] Unless otherwise specified, the raw materials used in the examples were purchased commercially.

[0036] The embodiment of the present invention adopts the following test method:

[0037] Microstructure observation: The microstructure of emulsion gel fat was observed using an optical microscope.

[0038] Rheological property testing: The tests were performed using a DHR-3 rotational rheometer. The linear viscoelastic region (LVR) was determined based on an amplitude sweep over a strain range of 0.01 to 100%. The frequency sweep test was performed over a frequency range of 0.1 Hz to 10 Hz. In addition, all tests were performed using a 40 mm aluminum plate with a gap value set to 1000 μm.

[0039] Dimensional feature measurement: A digital vernier caliper was used to measure the dimensional features of the 3D printed samples. The height and length of each 3D printed product of emulsion gel fat were measured three times at different positions, and the height difference, length difference and deformation rate between the actual product and the design model were calculated.

[0040] Example 1

[0041] (1) dissolving pea protein isolate powder in water to prepare a pea protein isolate solution with a mass concentration of 3%, stirring the solution under magnetic stirring at room temperature until the solution is completely dissolved, and refrigerating the solution in a refrigerator at 4° C. for 12 h to fully hydrate the solution to obtain a hydrated pea protein isolate solution;

[0042] (2) preparing a 1% solution of cotton-derived cellulose nanocrystals (purchased from Guilin Qihong Technology Co., Ltd.);

[0043] (3) mixing the pea protein isolate solution of step (1) and the cellulose nanocrystal solution of step (2) in a mass ratio of 1:1, adjusting the pH of the system to 3.0, and magnetically stirring for 2 h to obtain a protein-nanocrystal complex dispersion;

[0044] (4) Mix 24 g of soybean oil with 16 g of the protein-nanocrystal complex dispersion prepared in step (3), and homogenize at 12,000 rpm for 2 min to obtain an emulsion gel-like fat.

[0045] Example 2

[0046] The pH of the system in step (3) of Example 1 was adjusted to 4.5, and the rest was kept consistent with Example 1.

[0047] Example 3

[0048] The pH of the system in step (3) of Example 1 was adjusted to 8.0, and the rest was kept consistent with Example 1.

[0049] The emulsion gel fat obtained in Examples 1 to 3 was tested, and the test results are as follows:

[0050] Figure 1The laser confocal microscope images of Examples 1 to 3 are shown. The oil phase, pea protein isolate and cellulose nanocrystals are dyed respectively and observed by laser confocal microscope. From the oil-water distribution, it can be concluded that the prepared emulsion gel fat is an O / W structure. When the pH value is 3.0, a large number of pea protein isolate-cellulose nanocrystal aggregates can be seen at the oil-water interface and in the continuous phase. Under this condition, the oppositely charged pea protein isolate and cellulose nanocrystals are randomly combined by strong electrostatic interaction to form aggregates of different sizes. The increase in the hydrophilicity of pea protein isolate-cellulose nanocrystals enables them to be fixed on the interface, while the larger aggregates fill the continuous phase and play the role of thickener. When the pH value is close to the isoelectric point, a uniform and dense interface layer appears around the oil droplets, which indicates that both pea protein isolate and cellulose nanocrystals are firmly adsorbed on the interface, thereby effectively preventing the aggregation of oil droplets. At pH 8.0, the fluorescence signal of pea protein isolate at the interface is stronger, indicating that PPI plays a major role in stabilizing the emulsion, while cellulose nanocrystals tend to disperse in the aqueous phase due to electrostatic repulsion and high hydrophilicity. Pea protein isolate and cellulose nanocrystals have different interaction modes and mechanisms of stabilizing emulsions under different pH conditions, and the corresponding schematic diagrams are shown in Figure 2. Figure 2 shown.

[0051] Example 4

[0052] In step (4) of Example 1, 28 g of soybean oil was mixed with 12 g of the protein-nanocrystal complex dispersion in step (3), and the rest was the same as in Example 1.

[0053] Example 5

[0054] The pH of the system in step (3) of Example 1 was adjusted to 4.5. In step (4), 28 g of soybean oil was mixed with 12 g of the protein-nanocrystal complex dispersion in step (3). The rest was the same as in Example 1.

[0055] Example 6

[0056] The pH of the system in step (3) of Example 1 was adjusted to 8.0. In step (4), 28 g of soybean oil was mixed with 12 g of the protein-nanocrystal complex dispersion in step (3). The rest was the same as in Example 1.

[0057] Example 7

[0058] In step (4) of Example 1, 30 g of soybean oil was mixed with 10 g of the protein-nanocrystal complex dispersion in step (3), and the rest was the same as in Example 1.

[0059] Example 8

[0060] The pH of the system in step (3) of Example 1 was adjusted to 4.5. In step (4), 30 g of soybean oil was mixed with 10 g of the protein-nanocrystal complex dispersion in step (3). The rest was the same as in Example 1.

[0061] Example 9

[0062] The pH of the system in step (3) of Example 1 was adjusted to 8.0. In step (4), 30 g of soybean oil was mixed with 10 g of the protein-nanocrystal complex dispersion in step (3). The rest was the same as in Example 1.

[0063] Figure 3 The optical micrographs of Examples 1 to 9 are shown in FIG. Figure 3 It can be seen that the droplet sizes of Examples 5 and 8 are small and uniform, the droplets squeeze and support each other, and the obtained emulsion gel fat has a higher modulus and stability.

[0064] Figure 4 is the rheological diagram of Examples 1 to 9, wherein Figure 4 a is the strain sweep, Figure 4 b is the frequency sweep, Figure 4 c is the time scan. Figure 4 a shows the linear viscoelastic region of the emulsion gel, and the modulus of the emulsion gel with high oil phase under acidic conditions is higher; Figure 4 b It can be seen that the emulsion gel has a slight frequency dependence; Figure 4 c It can be seen that the emulsion gel fats of Examples 1 to 9 all exhibit the following characteristics during the time scanning process: the low strain scanning (first stage) is mainly elastic, the high strain scanning (second stage) is mainly viscous, and the recovery low strain scanning (third stage) is mainly elastic; however, there are differences in the structural recovery ability after high strain shearing. The higher the oil phase content, the better the recovery ability of the emulsion gel, and the emulsion gel with 60% oil phase has a poor structural recovery ability.

[0065] Figure 5 The figures are the actual objects of Examples 1 to 9. It can be seen from the figure that all the emulsion gels can remain stable within 30 days of storage at room temperature without obvious stratification. Among them, the samples with pH values ​​of 3.0 and 4.5 have the lowest viscoelasticity at an oil phase content of 60%, and gradually increase with the increase of the oil phase content, and the fluidity also decreases accordingly. In terms of apparent morphology, the different emulsions under this pH condition are generally not easy to flow. When the pH is 8.0, the samples with an oil phase ratio of 60% and 70% still have a certain fluidity, and the viscoelasticity of the emulsion gel is improved by further increasing the oil phase content.

[0066] Example 10

[0067] It can be seen from the above experiments that Examples 1, 2, 3, and 6 do not have good self-supporting properties and are not suitable for printing because of their general viscoelasticity or poor structural recovery ability. This example selects the emulsion gel fat food 3D printing of Examples 4, 5, 7, 8, and 9, with a needle diameter of 0.84 mm, a printing temperature and speed of 25°C and 80 mm / s, respectively, and selects cones, cylinders, and snowflakes for printing. A digital vernier caliper is used to measure the size of the printed product and calculate the deformation rate. The appearance of the 3D printed product is as follows: Figure 6 The cylinder model is used to evaluate the stacking of the latex gel during printing, the cone model is used to evaluate the ability of the latex gel to print a small area single layer structure, and the snowflake model is used to evaluate the fineness of the printed structure.

[0068] It can be seen that except Figure 6 Except for E (Example 9), all the emulsion gels can be used for 3D printing. This phenomenon may be due to the relatively low elastic modulus, severe collapse after printing, and poor molding ability. Both emulsion gels with pH values ​​of 3.0 and 4.5 can be uniformly squeezed out of the needle and maintain the printed structure. Figure 6 The snowflake and cylindrical models of B (Example 7) and 6D (Example 8) have complete structures, clear edges, and excellent self-supporting performance, but the deformation rate of the printed cone model is relatively large. Examples 7 and 8 are more suitable for printing flat stacked models and complex models. Figure 6 The fidelity of the emulsion gel printed snowflake and cylinder models of A (Example 4) and 6C (Example 5) is poor, but the surface of the printed cone model is more delicate and smoother. Examples 4 and 5 are more suitable for small-area single-layer structure models. This feature can be used to meet different appearance requirements of fat-like products.

[0069] Table 1 Size and deformation rate of 3D printed fat products of different emulsion gels

[0070]

[0071] Comparative Example 1

[0072] (1) dissolving pea protein isolate powder in water to prepare a pea protein isolate solution with a mass concentration of 2%, stirring the solution under magnetic stirring at room temperature until the solution is completely dissolved, and refrigerating the solution in a refrigerator at 4° C. for 12 h to fully hydrate the solution to obtain a hydrated pea protein isolate solution;

[0073] (2) adjusting the pH of the pea protein isolate solution in step (1) to 3.0, and magnetically stirring for 2 hours to obtain a protein dispersion;

[0074] (3) Mix 24 g of soybean oil with 16 g of the protein dispersion obtained in step (2), and homogenize at 12,000 rpm for 2 min to obtain an emulsion gel-like fat.

[0075] Comparative Example 2

[0076] The pH of the system in step (2) of Comparative Example 1 was adjusted to 4.5, and the rest was kept consistent with Comparative Example 1.

[0077] Comparative Example 3

[0078] The pH of the system in step (2) of Comparative Example 1 was adjusted to 8.0, and the rest was kept consistent with Comparative Example 1.

[0079] Comparative Example 4

[0080] In step (3) of comparative example 1, 28 g of soybean oil was mixed with 12 g of the protein dispersion in step (2), and the rest of the ingredients remained the same as those in comparative example 1.

[0081] Comparative Example 5

[0082] The pH of the system in step (2) of Comparative Example 1 was adjusted to 4.5. In step (3), 28 g of soybean oil was mixed with 12 g of the protein dispersion in step (2). The rest was kept consistent with Comparative Example 1.

[0083] Comparative Example 6

[0084] The pH of the system in step (2) of Comparative Example 1 was adjusted to 8.0. In step (3), 28 g of soybean oil was mixed with 12 g of the protein dispersion in step (2). The rest was kept consistent with Comparative Example 1.

[0085] Comparative Example 7

[0086] In step (3) of comparative example 1, 30 g of soybean oil was mixed with 10 g of the protein dispersion in step (2), and the rest was the same as comparative example 1.

[0087] Comparative Example 8

[0088] The pH of the system in step (2) of comparative example 1 was adjusted to 4.5. In step (3), 30 g of soybean oil was mixed with 10 g of the protein dispersion in step (2). The rest was kept consistent with comparative example 1.

[0089] Comparative Example 9

[0090] The pH of the system in step (2) of Comparative Example 1 was adjusted to 8.0. In step (3), 30 g of soybean oil was mixed with 10 g of the protein dispersion in step (2). The rest was kept consistent with Comparative Example 1.

[0091] The macroscopic images of the emulsion gel fats prepared in Comparative Examples 1 to 9 are as follows: Figure 7As shown. It can be seen that the stabilization mechanism of the emulsion at pH 8.0 is similar to the results of Examples 3, 6, and 9. At pH 3.0 and 4.5, the emulsification of pea protein isolate is poor, and the prepared emulsion has poor self-support and is easy to flow. During storage, the emulsion is unstable and there is an obvious phase separation phenomenon. The emulsion gel fats prepared in Comparative Examples 1 to 9 are not suitable for 3D printing.

[0092] Embodiment 11

[0093] The pea protein isolate powder in Example 4 was replaced by soy protein isolate powder, broad bean protein isolate powder, mung bean protein isolate powder, oat protein isolate powder, quinoa protein isolate powder, and peanut protein isolate powder, respectively, and the rest was consistent with Example 4, to obtain different types of emulsion gel fats.

[0094] Example 12

[0095] The cotton-derived cellulose nanocrystals in Example 4 were replaced with cellulose nanocrystals, starch nanocrystals, and chitin nanocrystals derived from wood pulp, algae, bacteria, or microcrystalline cellulose, respectively, and the rest remained the same as Example 4, to obtain different types of emulsion gel fats.

[0096] Example 13

[0097] The soybean oil in Example 4 was replaced by rapeseed oil, peanut oil, corn oil, sesame oil, sunflower oil, wheat germ oil, rice bran oil, almond oil, olive oil, and palm oil, respectively, while the other ingredients remained the same as in Example 4, to obtain different types of emulsion gel fats.

[0098] Embodiment 14

[0099] The pea protein isolate powder in Example 5 was replaced by soy protein isolate powder, broad bean protein isolate powder, mung bean protein isolate powder, oat protein isolate powder, quinoa protein isolate powder, and peanut protein isolate powder, respectively, and the rest was consistent with Example 5, to obtain different types of emulsion gel fats.

[0100] Embodiment 15

[0101] The cotton-derived cellulose nanocrystals in Example 5 were replaced with cellulose nanocrystals, starch nanocrystals, and chitin nanocrystals derived from wood pulp, algae, bacteria, or microcrystalline cellulose, respectively, while the rest remained the same as Example 5, to obtain different types of emulsion gel fats.

[0102] Example 16

[0103] The soybean oil in Example 5 was replaced by rapeseed oil, peanut oil, corn oil, sesame oil, sunflower oil, wheat germ oil, rice bran oil, almond oil, olive oil, and palm oil, respectively, while the other ingredients remained the same as in Example 5, to obtain different types of emulsion gel fats.

[0104] The emulsion gel fat prepared in Examples 11 to 16 was used for food 3D printing, and the experimental conditions were consistent with Example 10. The experimental results showed that the fidelity of the snowflake and cylindrical models printed in Examples 11 to 16 was poor, but the surface of the printed cone model was finer and smoother. Examples 11 to 16 were all suitable for small-area single-layer structure models.

[0105] Embodiment 17

[0106] The pea protein isolate powder in Example 7 was replaced by soy protein isolate powder, broad bean protein isolate powder, mung bean protein isolate powder, oat protein isolate powder, quinoa protein isolate powder, and peanut protein isolate powder, respectively, and the rest was consistent with Example 7, to obtain different types of emulsion gel fats.

[0107] Embodiment 18

[0108] The cotton-derived cellulose nanocrystals in Example 7 were replaced with cellulose nanocrystals, starch nanocrystals, and chitin nanocrystals derived from wood pulp, algae, bacteria, or microcrystalline cellulose, respectively, while the rest remained the same as Example 7, to obtain different types of emulsion gel fats.

[0109] Embodiment 19

[0110] The soybean oil in Example 7 was replaced by rapeseed oil, peanut oil, corn oil, sesame oil, sunflower oil, wheat germ oil, rice bran oil, almond oil, olive oil and palm oil, respectively, while the other ingredients remained the same as in Example 7, to obtain different types of emulsion gel fats.

[0111] Embodiment 20

[0112] The pea protein isolate powder in Example 8 was replaced by soy protein isolate powder, broad bean protein isolate powder, mung bean protein isolate powder, oat protein isolate powder, quinoa protein isolate powder, and peanut protein isolate powder, respectively, and the rest was consistent with Example 8 to obtain different types of emulsion gel fats.

[0113] Embodiment 21

[0114] The cotton-derived cellulose nanocrystals in Example 8 were replaced with cellulose nanocrystals, starch nanocrystals, and chitin nanocrystals derived from wood pulp, algae, bacteria, or microcrystalline cellulose, respectively, while the other conditions remained the same as Example 8, to obtain different types of emulsion gel fats.

[0115] Embodiment 22

[0116] The soybean oil in Example 8 was replaced by rapeseed oil, peanut oil, corn oil, sesame oil, sunflower oil, wheat germ oil, rice bran oil, almond oil, olive oil and palm oil respectively, while the other ingredients remained the same as in Example 8, to obtain different types of emulsion gel fats.

[0117] The emulsion gel fats prepared in Examples 17 to 22 were used for food 3D printing, and the experimental conditions were consistent with those in Example 10. The experimental results showed that the snowflake and cylindrical models printed by the emulsion gels in Examples 17 to 22 had complete structures, clear edges, and excellent self-supporting properties, but the deformation rate of the printed cone model was large. Examples 17 to 22 were suitable for printing flat stacked models and complex models.

[0118] The present invention changes the electrostatic interaction between the separated protein and the nanocrystal by adjusting the pH, thereby changing the emulsification properties of the protein-nanocrystal. The protein-nanocrystal complex generated by the electrostatic interaction can form an emulsion gel with good viscoelasticity and stability under low concentration conditions. The preparation process is simple and convenient, no surfactant is added, the amount of emulsification stabilizing components is small, and it is green and safe.

[0119] The present invention adjusts the physical properties of the emulsion gel fat by changing the oil phase ratio, and is suitable for application scenarios of different fat products; it does not contain trans fatty acids and has a low saturated fatty acid content, and can achieve partial or complete replacement of traditional plastic fats.

[0120] The emulsion gel fat prepared by the present invention can be evenly filamented during the printing process and can quickly recover its rigidity after extrusion. The printed product has excellent self-support and printing fidelity, and is suitable as a substitute for traditional plastic fat for personalized customization of products.

[0121] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a protein-nanocrystal stabilized emulsion gel fat, characterized in that: include, Providing a protein isolate solution and fully hydrating it; providing a nanocrystal solution; The separated protein solution and the nanocrystal solution are mixed, and the pH of the system is adjusted to 3-9 to prepare a protein-nanocrystal complex dispersion; The oil phase is mixed with the protein-nano crystal complex dispersion, and high-speed shearing and homogenization are performed to obtain an emulsion gel-like fat.

2. The method for preparing the protein-nanocrystal stabilized emulsion gel fat according to claim 1, characterized in that: The isolated protein includes one of pea isolated protein, soybean isolated protein, broad bean isolated protein, mung bean isolated protein, oat isolated protein, quinoa isolated protein and peanut isolated protein.

3. The method for preparing the protein-nanocrystal stabilized emulsion gel fat according to claim 1 or 2, characterized in that: The mass concentration of the isolated protein solution is 1-5%.

4. The method for preparing the protein-nanocrystal stabilized emulsion gel fat as claimed in claim 3, characterized in that: The hydration condition of the isolated protein solution is refrigeration at 1 to 10° C. for 6 to 12 hours.

5. The method for preparing the protein-nanocrystal stabilized emulsion gel fat according to any one of claims 1, 2 and 4, characterized in that: The nanocrystals include one or more of cellulose nanocrystals derived from cotton, wood pulp, algae, bacteria or microcrystalline cellulose, starch nanocrystals or chitin nanocrystals.

6. The method for preparing the protein-nanocrystal stabilized emulsion gel fat according to claim 5, characterized in that: The mass ratio of the protein to the nanocrystal is 1:1-5:1, and the mass concentration of the protein-nanocrystal complex in the water phase is 1-5%.

7. The method for preparing a protein-nanocrystal stabilized emulsion gel fat according to any one of claims 1, 2, 4, and 6, characterized in that: The oil phase comprises liquid edible oil, including one or more of soybean oil, rapeseed oil, peanut oil, corn oil, sesame oil, sunflower oil, wheat germ oil, rice bran oil, almond oil, olive oil, and palm oil; the mass percentage of the oil phase is 60-75%.

8. The method for preparing the protein-nanocrystal stabilized emulsion gel fat according to claim 7, characterized in that: The high-speed shearing homogenization is carried out at 8000-15000 rpm for 1-3 minutes.

9. The protein-nanocrystal stabilized emulsion gel fat obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the protein-nanocrystal stabilized emulsion gel fat as claimed in claim 9 in 3D printing.

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