Peanut oil body based 3D printing ink and preparation method thereof

Abstract

The invention relates to the technical field of 3D printing ink materials, in particular to peanut oil body based 3D printing ink and a preparation method thereof.The preparation method comprises the following steps that S1, peanut slurry is prepared, specifically, peanuts are selected, soaked, peanut red skin removing, cleaning, mixing with water, pulping and filtering are conducted, and the peanut slurry is obtained; s2, post-treatment of the peanut slurry: adjusting the pH value of the peanut slurry to 7-11 by using a pH regulator to obtain treated peanut slurry; s3, preparation of a peanut oil body: centrifuging the treated peanut slurry, and taking an upper-layer white enriched product, so as to obtain the peanut oil body; s4, preparation of the peanut oil body based 3D printing ink: the peanut oil body is placed at the temperature of 4 DEG C for heat preservation and stabilization for 6-12 h, and the peanut oil body based 3D printing ink is obtained. The peanut oil body-based 3D printing ink prepared by the preparation method can be used for 3D printing without additional addition of an auxiliary agent, and a printed product is relatively good in precision and stability.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing ink materials, and in particular to a peanut oil-based 3D printing ink and a preparation method thereof. Background Art

[0002] As an advanced additive manufacturing technology, 3D printing is of great significance for the production of medical stents and special foods. Due to the fluidity of liquid oils, they cannot be smoothly extruded from the nozzle of a 3D printer, so there are relatively few studies on 3D printing of lipid matrices. Therefore, it is crucial to develop a lipid matrix raw material that can be used for 3D printing. The internal phase volume fraction of high internal phase emulsions (HIPEs) exceeds the stacking limit (≥74%) and exhibits semi-solid properties. The higher viscosity enables them to be smoothly extruded from the nozzle of the printer and maintain a certain degree of independence, making them an excellent raw material for forming lipid-based 3D printing materials. At present, most of the preparation studies of HIPE use additional additives to stabilize and crosslink the oil droplets, and their biocompatibility needs to be evaluated. In addition, an inappropriate oil-water ratio may lead to phase separation. Therefore, it is crucial to develop a new food-grade ink material for 3D printing lipid matrices, which will provide new opportunities for food 3D printing.

[0003] Plant oil bodies are discrete organelles that store lipids in seeds and are formed as a natural process of plant growth and development. They are a stable emulsified system that can demonstrate resistance to environmental threats. When oil body particles are extracted from plants, the plants are damaged by high-speed shear forces and macromolecules are dispersed in a water-based solution. The oil body interface exhibits self-assembly behavior, forming natural emulsified oil droplet particles surrounded by a composite membrane with triglycerides as the core and phospholipids and proteins as the interface. The entire system acts as an emulsion template, and its various properties can be improved by changing the interface layer of the oil body. In addition, it has the characteristics of efficient extraction, environmental protection and natural origin. Therefore, plant oil bodies are a natural HIPE similar to Pickering emulsions, which can be used as a lipid matrix raw material for 3D printing soft matter food.

[0004] However, to date, existing research has improved the performance and stability of plant oils to meet 3D printing requirements by adding additional additives, but the feasibility of directly using plant oils as 3D printing inks has not been studied. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the current natural liquid oil cannot be used for 3D printing and the stability and biocompatibility of HIPE are poor. A peanut oil body-based 3D printing ink and a preparation method thereof are proposed. The peanut oil body-based 3D printing ink obtained by the preparation method is used for 3D printing, and the obtained printed products have strong stability and self-supporting performance.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing peanut oil-based 3D printing ink, the preparation method comprising the following steps:

[0007] S1. Preparation of peanut slurry

[0008] The peanuts are selected, soaked, peeled, washed, mixed with water, pulped, and filtered to obtain peanut pulp;

[0009] S2. Post-treatment of peanut slurry

[0010] Using a pH regulator to adjust the pH of the peanut slurry to 7-11 to obtain a treated peanut slurry;

[0011] S3. Preparation of Peanut Oil Bodies

[0012] Centrifuging the treated peanut slurry and taking the upper white enriched matter to obtain peanut oil bodies;

[0013] S4. Preparation of peanut oil-based 3D printing ink

[0014] The peanut oil body is placed at a temperature of 4° C. and kept stable for 6-12 hours to obtain a peanut oil body-based 3D printing ink.

[0015] In the above technical scheme, the post-treatment of the peanut slurry is crucial. The pH of the peanut slurry is adjusted to 9-11 by a pH adjuster, and 11 is most preferred. When the pH of the peanut slurry is too low, the printing effect of the peanut oil body-based 3D printing ink is poor, and the stability of the printed product is insufficient. When the pH of the peanut slurry is too high, the high oleic acid peanut oil body will demulsify and form liquid oil, making it unusable for 3D printing.

[0016] Preferably, in step S1, the specific conditions of the soaking are: soaking temperature 4°C, soaking time 16-20h.

[0017] In the above technical solution, soaking peanuts at 4°C can delay the oxidation of oil and improve the quality of high oleic peanut oil.

[0018] Preferably, in step S2, the pH adjuster is an alkaline pH adjuster, and the pH adjuster is selected from KOH, NaOH or NaHCO3, and is more preferably KOH.

[0019] Preferably, in step S3, the specific conditions of the centrifugation are: centrifugal speed 4000-10000 rpm, and centrifugal time 15-30 min.

[0020] Preferably, in step S1, the mass volume ratio of the washed peanuts to water is 1:6-10 (kg / L), more preferably 1:8 (kg / L).

[0021] Preferably, the peanuts are high oleic peanuts.

[0022] Preferably, in step S2, the pH of the peanut slurry is adjusted to 11.

[0023] A peanut oil body-based 3D printing ink prepared by the preparation method as described above.

[0024] An application of the peanut oil body-based 3D printing ink in 3D printing, wherein the oleic acid content in the peanut oil body is 80-85%.

[0025] Preferably, the parameters of the 3D printing are: printing temperature 20-25°C, printing speed 30-35mm / s, nozzle diameter 0.84-1.2mm, material extrusion speed 100%, and further preferably: printing temperature 25°C, printing speed 35mm / s, nozzle diameter 1.2mm, material extrusion speed 100%.

[0026] The beneficial effects of the present invention are:

[0027] 1. The peanut oil-based 3D printing ink prepared by the present invention can achieve self-supporting without the need for adding an additional cross-linking agent and can be used for 3D printing.

[0028] 2. The method for preparing the peanut oil-based 3D printing ink of the present invention is simple, and the rheological properties can be adjusted by controlling the pH value of the peanut slurry, thereby improving the 3D printing accuracy.

[0029] 3. The peanut oil-based 3D printing ink prepared by the present invention is of natural origin, adopts green processing technology, retains the original biologically active ingredients in the plant body, and has high nutritional value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the infrared spectrum of the peanut oil body-based 3D printing ink prepared in Comparative Examples 1-3 and Examples 1-3;

[0031] Figure 2 The protein secondary structure diagram of the peanut oil body-based 3D printing ink prepared in Comparative Examples 1-3 and Examples 1-3;

[0032] Figure 3 The Raman spectra of the peanut oil body-based 3D printing ink prepared in Comparative Examples 1-3 and Examples 1-3;

[0033] Figure 4This is a peak ratio diagram of the Raman spectrum of the peanut oil body-based 3D printing ink prepared in Comparative Examples 1-3 and Examples 1-3;

[0034] Figure 5 Zeta potential diagram of the peanut oil body-based 3D printing ink prepared in Comparative Examples 1-3 and Examples 1-3;

[0035] Figure 6 The rheological properties of the peanut oil-based 3D printing inks prepared in Comparative Examples 1-3 and Examples 1-3 are shown in Figure 1, wherein (a) is the storage modulus, (b) is the loss modulus, (c) is tanδ, and (d) is the apparent viscosity;

[0036] Figure 7 This is a graph of the emulsification activity index of the peanut oil-based 3D printing ink prepared in Comparative Examples 1-3 and Examples 1-3;

[0037] Figure 8 This is a comparison diagram of the contact angles of the peanut oil-based 3D printing inks prepared in Comparative Examples 1-3 and Examples 1-3;

[0038] Fig. 9 The printing effect diagram of the peanut oil-based 3D printing ink prepared in Comparative Example 1-3 and Example 1-3;

[0039] Fig.10 These are the printing deviation diagrams of the peanut oil-based 3D printing inks prepared in Comparative Example 1-3 and Example 1-3, (a) is Comparative Example 1-3, and (b) is Example 1-3. DETAILED DESCRIPTION

[0040] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0042] The present invention is now further described in conjunction with specific examples. The following examples are only for explaining the present invention, but do not constitute a limitation of the present invention. The test samples and test processes used in the following examples include the following (if the specific experimental conditions are not indicated in the examples, they are usually in accordance with conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following examples, if not otherwise specified, can all be obtained from commercial channels).

[0043] Example 1

[0044] A method for preparing peanut oil-based 3D printing ink, the specific steps of the preparation method are as follows:

[0045] S1. Preparation of peanut slurry

[0046] The peanuts were selected to remove moldy and inferior peanuts; soaked in 4°C water for 20 hours; the red skin of the peanuts was removed; 8 times the mass of water was added, and the peanuts were ground at 18000r / min for 3 minutes to obtain peanut slurry.

[0047] S2. Post-treatment of peanut slurry

[0048] 1 mol / L KOH solution was added to the peanut slurry, the pH value was adjusted to 7.0, and the mixture was mixed evenly to obtain the treated peanut slurry.

[0049] S3. Preparation of Peanut Oil Bodies

[0050] The treated peanut slurry was centrifuged at 10,000 rpm for 20 min, and the upper white enriched material was taken to obtain peanut oil bodies.

[0051] S4. Preparation of peanut oil-based 3D printing ink

[0052] The peanut oil body was placed at a temperature of 4° C. and kept stable for 6-12 hours to obtain a peanut oil body-based 3D printing ink (denoted as HPOB-7.0).

[0053] The peanuts are selected from high oleic peanuts "Weihua No. 25".

[0054] Example 2

[0055] A method for preparing peanut oil-based 3D printing ink, the specific steps of the preparation method are as follows:

[0056] S1. Preparation of peanut slurry

[0057] The peanuts were selected to remove moldy and inferior peanuts; soaked in 4°C water for 20 hours; the red skin of the peanuts was removed; 8 times the mass of water was added, and the peanuts were ground at 18000r / min for 3 minutes to obtain peanut slurry.

[0058] S2. Post-treatment of peanut slurry

[0059] 1 mol / L KOH solution was added to the peanut slurry, the pH value was adjusted to 9.0, and the mixture was mixed evenly to obtain the treated peanut slurry.

[0060] S3. Preparation of peanut oil bodies

[0061] The treated peanut slurry was centrifuged at 10,000 rpm for 20 min, and the upper white enriched material was taken to obtain peanut oil bodies.

[0062] S4. Preparation of peanut oil-based 3D printing ink

[0063] The peanut oil body was placed at a temperature of 4° C. and kept stable for 6-12 hours to obtain a peanut oil body-based 3D printing ink (denoted as HPOB-9.0).

[0064] The peanuts are selected from high oleic peanuts "Weihua No. 25".

[0065] Example 3

[0066] A method for preparing peanut oil-based 3D printing ink, the specific steps of the preparation method are as follows:

[0067] S1. Preparation of peanut slurry

[0068] The peanuts were selected to remove moldy and inferior peanuts; soaked in 4°C water for 20 hours; the red skin of the peanuts was removed; 8 times the mass of water was added, and the peanuts were ground at 18000r / min for 3 minutes to obtain peanut slurry.

[0069] S2. Post-treatment of peanut slurry

[0070] 1 mol / L KOH solution was added to the peanut slurry, the pH value was adjusted to 11.0, and the mixture was mixed evenly to obtain the treated peanut slurry.

[0071] S3. Preparation of Peanut Oil Bodies

[0072] The treated peanut slurry was centrifuged at 10,000 rpm for 20 min, and the upper white enriched material was taken to obtain peanut oil bodies.

[0073] S4. Preparation of peanut oil-based 3D printing ink

[0074] The peanut oil body was placed at a temperature of 4° C. and kept stable for 6-12 hours to obtain a peanut oil body-based 3D printing ink (denoted as HPOB-11.0).

[0075] The peanuts are selected from high oleic peanuts "Weihua No. 25".

[0076] Comparative Example 1

[0077] A method for preparing peanut oil-based 3D printing ink, the specific steps of the preparation method are as follows:

[0078] S1. Preparation of peanut slurry

[0079] The peanuts were selected to remove moldy and inferior peanuts; soaked in 4°C water for 20 hours; the red skin of the peanuts was removed; 8 times the mass of water was added, and the peanuts were ground at 18000r / min for 3 minutes to obtain peanut slurry.

[0080] S2. Post-treatment of peanut slurry

[0081] 1 mol / L KOH solution was added to the peanut slurry, the pH value was adjusted to 7.0, and the mixture was mixed evenly to obtain the treated peanut slurry.

[0082] S3. Preparation of Peanut Oil Bodies

[0083] The treated peanut slurry was centrifuged at 10,000 rpm for 20 min, and the upper white enriched material was taken to obtain peanut oil bodies.

[0084] S4. Preparation of peanut oil-based 3D printing ink

[0085] The peanut oil body was placed at a temperature of 4° C. and kept stable for 6-12 hours to obtain a peanut oil body-based 3D printing ink (denoted as HPOB-7.0).

[0086] The peanuts are selected from the low oleic acid peanut "Xiaobaisha".

[0087] Comparative Example 2

[0088] A method for preparing peanut oil-based 3D printing ink, the specific steps of the preparation method are as follows:

[0089] S1. Preparation of peanut slurry

[0090] The peanuts were selected to remove moldy and inferior peanuts; soaked in 4°C water for 20 hours; the red skin of the peanuts was removed; 8 times the mass of water was added, and the peanuts were ground at 18000r / min for 3 minutes to obtain peanut slurry.

[0091] S2. Post-treatment of peanut slurry

[0092] 1 mol / L KOH solution was added to the peanut slurry, the pH value was adjusted to 9.0, and the mixture was mixed evenly to obtain the treated peanut slurry.

[0093] S3. Preparation of Peanut Oil Bodies

[0094] The treated peanut slurry was centrifuged at 10,000 rpm for 20 min, and the upper white enriched material was taken to obtain peanut oil bodies.

[0095] S4. Preparation of peanut oil-based 3D printing ink

[0096] The peanut oil body was placed at a temperature of 4° C. and kept stable for 6-12 hours to obtain a peanut oil body-based 3D printing ink (denoted as HPOB-9.0).

[0097] The peanuts are selected from the low oleic acid peanut "Xiaobaisha".

[0098] Comparative Example 3

[0099] A method for preparing peanut oil-based 3D printing ink, the specific steps of the preparation method are as follows:

[0100] S1. Preparation of peanut slurry

[0101] The peanuts were selected to remove moldy and inferior peanuts; soaked in 4°C water for 20 hours; the red skin of the peanuts was removed; 8 times the mass of water was added, and the peanuts were ground at 18000r / min for 3 minutes to obtain peanut slurry.

[0102] S2. Post-treatment of peanut slurry

[0103] 1 mol / L KOH solution was added to the peanut slurry, the pH value was adjusted to 11.0, and the mixture was mixed evenly to obtain the treated peanut slurry.

[0104] S3. Preparation of Peanut Oil Bodies

[0105] The treated peanut slurry was centrifuged at 10,000 rpm for 20 min, and the upper white enriched material was taken to obtain peanut oil bodies.

[0106] S4. Preparation of peanut oil-based 3D printing ink

[0107] The peanut oil body was placed at a temperature of 4° C. and kept stable for 6-12 hours to obtain a peanut oil body-based 3D printing ink (denoted as HPOB-11.0).

[0108] The peanuts are selected from the low oleic acid peanut "Xiaobaisha".

[0109] The peanut oil-based 3D printing inks prepared in Examples 1-3 and Comparative Examples 1-3 were analyzed for basic components, physical stability, and oxidative stability. The specific testing methods are as follows:

[0110] 1. Basic component test method:

[0111] Determination of moisture content: refer to GB 5009.3-2016, use direct drying method at 105℃ to constant weight.

[0112] Determination of oil content: refer to GB 5009.6-2016 and use Soxhlet extraction method for determination.

[0113] Determination of protein content: refer to GB 5009.5-2016 and use Kjeldahl method for determination.

[0114] Determination of phospholipid content: refer to GB-5537-2008 and use molybdenum blue colorimetry for determination.

[0115] Determination of particle size: The sample was diluted 10 times with deionized water, and then 1% (v / v) Nile red and fluorescein isothiocyanate (FITC) were added and stirred vigorously for 1 minute. Protein and lipid were stained with FITC and Nile red, respectively. The stained oil body samples were observed under a laser confocal scanning microscope (FV3000, Olympus, Japan), with excitation wavelengths of 488nm and 559nm, respectively. The obtained laser confocal microscopy images were analyzed by ImageJ software, the diameter of the particles in the oil body (>100 single droplets) was measured, and the average particle size of the oil body was calculated by fitting the Gaussian distribution.

[0116] The test results of basic components of the peanut oil-based 3D printing inks prepared in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1.

[0117] Table 1 Basic component test results of peanut oil body-based 3D printing ink prepared in Examples 1-3 and Comparative Examples 1-3

[0118] Moisture (%) grease(%) protein(%) Phospholipids (%) Particle size (micrometer) Example 1 16.79±0.60 81.76±2.88 1.35±0.06 1.31±0.05 1.26±0.05 Example 2 13.71±1.05 85.07±2.34 1.22±0.03 0.69±0.01 1.04±0.03 Example 3 12.26±0.46 86.75±0.63 0.99±0.02 0.42±0.02 0.90±0.03 Comparative Example 1 19.19±0.84 79.38±1.68 1.43±0.12 1.26±0.04 2.19±0.05 Comparative Example 2 17.33±1.19 81.44±0.89 1.26±0.03 0.55±0.10 1.68±0.05 Comparative Example 3 14.34±0.99 84.60±1.43 1.06±0.06 0.33±0.06 1.23±0.04

[0119] As can be seen from Table 1, under different pH alkaline conditions, the basic components and interface compositions of ordinary peanut oil bodies (LPOB, i.e., the peanut oil body-based 3D printing ink prepared in Comparative Examples 1-3) and high oleic peanut oil bodies (HPOB, i.e., the peanut oil body-based 3D printing ink prepared in Examples 1-3) are significantly different. The water content of both peanut oil bodies decreases with increasing pH. Among the samples, LPOB-7.0 and HPOB-7.0 have the highest water content, which are 19.19±0.84% ​​and 16.79±0.60%, respectively, followed by LPOB-9.0 and HPOB-9.0, which are 17.33±1.19% and 13.71±1.05%, respectively. LPOB-110 (13.34±0.99%) and HPOB-11.0 (12.26±0.46%) have the lowest water content, which may be due to the presence of protein and phospholipid content reduction in the oil body interface layer.

[0120] In an alkaline environment, elution of proteins and hydrolysis of phospholipids occurred. When the pH increased from 7.0 to 11.0, the protein content of LPOB decreased from 1.43 ± 0.12% to 1.06 ± 0.06%, while the phospholipid content increased from 1.26 ± 0.04% to 1.33 ± 0.06%. Similarly, the protein content of HPOB decreased from 1.35 ± 0.06% to 0.99 ± 0.02%, and the phospholipid content decreased from 1.11 ± 0.05% to 0.32 ± 0.02%, resulting in a decrease in hydration.

[0121] On a dry basis, there was no significant difference in the oil content of peanut oil bodies. However, the lipid percentage content of HPOB and LPOB increased with increasing alkaline pH. Specifically, it was 79.38 ± 1.68% for LPOB-7.0, 81.44 ± 0.89% for LPOB-9.0, and 84.60 ± 1.43% for LPOB-11.0, while it was 81.76 ± 2.88% for HPOB-7.0, 85.07 ± 2.34% for HPOB-9.0, and 86.75 ± 0.63% for HPOB-11.0. This phenomenon may be attributed to the composition of the oil bodies, which consist of an inner core material and an outer interface, resulting in different ratios of oil and water. Notably, at pH levels ranging from 7.0 to 11.0, both LPOB and HPOB exhibited an oil phase content of more than 74%, meeting the criteria for a high internal phase emulsion. This difference may be related to the different physical and chemical properties of the emulsions.

[0122] Both LPOB and HPOB exhibited a unimodal distribution at different pH levels. As the pH value increased, the average particle size of both oil bodies decreased, resulting in a more uniform particle size distribution. The stability of an oil body can be indicated in part by the size of its particles. In general, more stable emulsions tend to have smaller and more uniform particle size distributions in their systems. In addition, the particle size of an emulsion is related to the interfacial tension, which affects the rheology of the emulsion. For example, the average particle size of LPOB-7.0 was 2.19 ± 0.05 μm, LPOB-9.0 was 1.68 ± 0.04 μm, and LPOB-11.0 was 1.23 ± 0.04 μm. This trend is attributed to the fact that as the oil bodies approach their isoelectric point (pI) at lower pH levels, the large amount of foreign proteins on the interfacial layer promotes bridging interactions, weakens the electrostatic repulsion, and leads to particle aggregation and enlargement of size. In contrast, as the pH value increases away from the pI, the foreign proteins are gradually removed, exposing the phospholipid layer and increasing the surface charge of the oil bodies, thereby enhancing the electrostatic repulsion and reducing the particle size. In contrast, the average particle sizes of HPOB-7.0, HPOB-9.0, and HPOB-11.0 were 1.26 ± 0.05 μm, 1.04 ± 0.03 μm, and 0.90 ± 0.03 μm, respectively, which were significantly smaller than LPOB. This difference may stem from the difference in the raw materials of the two oil bodies, because differences in plant seed growth, development, and maturity lead to different compositions between the core material and the external interface of the oil body, even when extracted under similar conditions.

[0123] 2. Infrared spectrum test method:

[0124] Infrared spectroscopy was used to analyze the changes in the secondary structure of the oil body protein in the different treatment groups. The interface layer protein of the peanut oil body-based 3D printing ink prepared in Examples 1-3 and Comparative Examples 1-3 was extracted and separated, and freeze-dried to obtain frozen protein. The frozen protein and KBr were uniformly mixed at a ratio of 1:100 (w / w), ground and compressed for analysis. The infrared spectrum was between 4000 and 400 cm -1 Recorded at wavenumbers of 1 cm resolution -1 The test results are shown in Figure 1 , Figure 2 .

[0125] The stability of oil bodies depends largely on the interactions at the droplet interface. Conformational changes can be assessed by detecting amide I, II, and III protein bands. In FTIR analysis of protein secondary structure, 1600-1700 cm -1 The signal between 1648-1664 cm corresponds to the amide I band, which is affected by C=O stretching (~80%) and NH bending (~20%) effects. The IR spectra of LPOB and HPOB show that pH treatment affects the secondary structure of these proteins. -1The range represents α-helix, 1615-1637 cm -1 and 1682-1700cm -1 Indicates β-sheet, 1664-1681cm -1 Indicates β-turn, 1637-1648cm -1 Represents random coil. Oil bodies exhibit three main structures: α-helix, β-sheet, and β-turn. As the pH value increases, the α-helix content decreases, the β-sheet content increases, and the β-turn and random coil content decreases. The reduction of highly ordered structures (α-helix and β-sheet) indicates that the oil body structure has become more compact and ordered at the interface, which may be due to the reduction of the exogenous protein content, resulting in pure oil bodies similar to those containing only endogenous proteins.

[0126] The content of interfacial proteins in oil bodies varies with pH. As pH increases, the content of α-helix and β-sheet increases, while the content of β-turn and random coil decreases. The slight increase in α-helix content indicates that the hydrophobic region of the oil body remains highly stable, and pH mainly affects the hydrophilic regions of the N-terminus and C-terminus of the interfacial protein. The increase in β-sheet folding promotes the aggregation of interfacial proteins, resulting in a more compact and stable oil structure.

[0127] 3. Raman spectroscopy test method:

[0128] The peanut oil body-based 3D printing inks prepared in Examples 1-3 and Comparative Examples 1-3 were placed on the focusing platform of the Raman spectrometer laser, and their positions were adjusted as needed, and then the Raman test was continued. Ensure that the test site covers all relevant and representative areas of the sample. Use a 785nm laser to collect 400-4000cm -1 The Raman spectrum of the oil body within the range was scanned with a power of 100 mW and a collection time of 20 s. The test results are shown in Figure 3 , Figure 4 .

[0129] At 2855cm -1 The CH2 symmetric stretching band was observed at 2900 cm -1A CH2 asymmetric stretching band was observed at 1.50 Å. The intensity ratio of I2855 / I2900, as an indicator of lipid stacking effect, reflects the ordered / disordered state of acyl chains and interchain interactions. The I2855 / I2900 intensity ratios of LPOB and HPOB extracted at pH 7.0, 9.0, and 11.0 were 1.34±0.02, 1.31±0.02, 1.26±0.04 and 1.37±0.03, 1.30±0.04, 1.22±0.02, respectively. A lower intensity ratio indicates increased interchain vibrational coupling and decreased acyl chain mobility, indicating that more protein chains are inserted into lipid acyl chains, resulting in hydrophobic interactions between lipid CH groups and proteins, enhancing effectiveness and stability.

[0130] 4. Zeta-potential test method:

[0131] Deionized water was added to dilute the peanut oil-based 3D printing inks prepared in Examples 1-3 and Comparative Examples 1-3 into 1% mass fraction emulsions. The emulsions treated at different pH values ​​were analyzed using a laser scattering instrument (Zetasizer Nano ZS90) at 25°C. The test results are shown in Figure 5 .

[0132] The dispersion stability of oil bodies is affected by electrostatic repulsion, steric hindrance, and hydrophobic interactions. Electrostatic repulsion is mainly determined by the surface charge of the oil bodies, as shown by their zeta potential. Two types of peanut oil bodies were extracted at pH 7.0, 9.0, and 11.0. The zeta potential of LPOB was measured to be -18.12±1.04mV, -19.63±1.74mV, and -22.11±1.07mV, and the potential of HPOB was measured to be -20.44±3.04mV, -23.14±1.37mV, and -25.48±1.16mV, indicating an increase in electrostatic repulsion. The increase in pH leads to the increase of H in water. + The reduction of protons enhances the electrostatic repulsion between oil bodies.

[0133] 5. Rheological properties test method:

[0134] The rheological properties of the peanut oil-based 3D printing inks prepared in Examples 1-3 and Comparative Examples 1-3 were evaluated using a rotational rheometer (Discovery HR-1, TA Instruments, New Castel, DE, US). Frequency sweep measurements were performed in the range of 0.1-100 Hz to monitor the storage modulus and loss modulus (G' and G") of the ink while maintaining a fixed strain of 1% in the linear viscoelastic region. In addition, shear sweeps were performed at shear rates from 0.1 to 100 1 / s to study the effect of shear rate on the apparent viscosity (η) of the ink. All measurements were performed at a temperature of 25°C, and the test results are shown in Figure 6 .

[0135] The apparent viscosity of LPOB and HPOB gradually decreases with increasing shear rate, showing shear thinning behavior. This phenomenon is attributed to droplet aggregation and flocculation behavior. At low shear rates, as the shear rate increases, the aggregation of oil droplets is destroyed, resulting in a sharp decrease in the apparent viscosity of each oil body, showing pseudoplastic fluid characteristics. When the shear rate reaches a certain point, the apparent viscosity of each oil body remains relatively stable, indicating the characteristics of a Newtonian fluid.

[0136] The viscoelastic properties of the oil bodies can be described in terms of the storage modulus G' and the loss modulus G". Within the specified frequency range, the storage modulus G' of each ink consistently exceeds the loss modulus G", indicating that the inks exhibit stable behavior dominated by elasticity. In general, G' and G" are usually related to the energy stored during the oscillation of the emulsion and the energy dissipated by heating.

[0137] from Figure 6 It can be seen from (a)(b) that in the frequency sweep experiment, the G' of both oil inks is greater than G". As the frequency increases, the G' and G" values ​​of LPOB and HPOB gradually increase, indicating that the elasticity and viscosity of the oils gradually increase after pH adjustment, and both exhibit viscoelasticity. In addition, the G' and G" of HPOB at the same pH at different frequencies are higher than those of LPOB, which indicates that the internal structure of HPOB may be more compact and have a stronger ability to recover after deformation.

[0138] like Figure 6 As shown in (c), the tanδ of LPOB and HPOB are both <1. The larger the value of tanδ, the greater the proportion of viscous components in the system, and the system exhibits fluid properties. Conversely, the smaller the tanδ value, the more elastic components in the system, and the system exhibits solid properties. Compared with LPOB, HPOB has a lower tanδ value and stronger support. In addition, the oil body provides additional steric hindrance, thereby providing a buffer for the extrusion collision between the oil bodies, which can make printing go smoothly.

[0139] like Figure 6 As shown in (d), the apparent viscosity of LPOB and HPOB tends to decrease with increasing shear rate, showing typical shear-thinning pseudoplastic behavior. This may be due to the destruction of specific structures in the high internal phase emulsion of the oil body, which makes the molecules linearly arranged in the direction of the shear rate. When the shear rate increases, the relatively dispersed particles in the emulsion system are subjected to shear stress between the flow layers, reducing mutual adhesion and collusion, which is manifested as a decrease in viscosity. The apparent viscosity of HPOB is greater than that of LPOB, and as the apparent viscosity increases, the movement of the droplets slows down, which leads to an increase in the stability of the system, which is manifested as a smaller printing deviation during 3D printing and molding.

[0140] 6. Emulsification activity test method:

[0141] The emulsification activity index (EAI) and emulsion stability index (ESI) were determined using a modified version of the turbidity method. The peanut oil-based 3D printing inks prepared in Examples 1-3 and Comparative Examples 1-3 were homogenized, 50 mL of the emulsion was taken from the bottom, and immediately added to 10 mL of 0.1% (w / v) SDS solution. The absorbance was measured using a UV-vis spectrophotometer (UV-2600, Toshiba, Kyoto, Japan). EAI and ESI were calculated according to the following equations:

[0142]

[0143] Where A0 is the initial absorbance (at 0 minutes), N is the dilution factor, C is the initial protein concentration, is the volume fraction of oil in the emulsion (0.20).

[0144] ESI(min)=A0 / (A0-A 10 )×(T 10 -T0)

[0145] Among them A 10 is the absorbance recorded 10 min after homogenization, T0 and T 10 Respectively represent 0 minutes and 10 minutes, and the test results are shown in Figure 7 .

[0146] The emulsifying activity index (EAI) measures the coverage of the oil-water interface per unit mass of POB in the emulsion, while the emulsion stability index (ESI) indicates the ability of the protein to remain at the oil-water interface after storage in the emulsion. After alkaline pH treatment, both the EAI and ESI of LPOB and HPOB continued to increase with increasing pH levels. LPOB-7.0 exhibited the lowest EAI and ESI values, which were 4.9 ± 0.43 m / s, respectively. 2 / g and 109.62±2.62min, while HPOB-11.0 showed the highest EAI value and ESI, which were 9.94±0.10m 2 / g and 295.24±5.87min. This trend indicates that with the increase of alkaline pH, the hydrophobic groups of proteins in the oil bodies become more exposed, thus being able to interact with the oil phase, thereby enhancing the emulsification properties of the oil bodies.

[0147] Emulsifying activity refers to the ability of a protein to adsorb and form an emulsion at the oil-water interface, and is usually quantified by the emulsifying activity index (EAI). The emulsifying stability index (ESI) measures the ability of an emulsion to maintain its structure over a specific period of time. Despite having smaller interfacial proteins, the EAI and ESI of high-oleic peanut oil bodies were significantly better than those of normal peanut oil bodies. This difference may stem from the fact that the interfacial proteins in high-oleic peanut oil bodies are mainly endogenous, showing stronger hydrophobic interactions and significantly higher emulsifying ability and stability compared to exogenous proteins.

[0148] The trend of the emulsification properties of oil bodies is highly similar to that of surface hydrophobicity. This is because more hydrophobic groups exposed to non-covalent bonds of the interfacial proteins of the oil bodies regulated by pH increase the interfacial strength, resulting in a greater ability to emulsify oil per unit mass of oil bodies and contributing to the maintenance of the ESI of the emulsion to some extent.

[0149] 7. Contact angle test method:

[0150] The wettability of the ink was evaluated by measuring the contact angle of a water drop in air on the ink film. A thin film of ink was spread on a glass slide, and 2 μL of water was gently dropped onto its surface. A high-speed camera mounted on a Flex interfacial tensiometer (Biolin Scientific AB, Sweden) recorded the evolution of the drop shape. The profile data was then automatically input into the Laplace-Young equation to calculate the contact angle, and the test results are shown in Figure 8 .

[0151] Contact angle measurement is a valuable technique for evaluating the hydrophobic properties of materials. It is generally believed that particles with a contact angle of about 90° have the best emulsification ability. In the present invention, the contact angles of LPOB and HPOB at the droplet interface were measured under different pH conditions of 7.0, 9.0, and 11.0. The results show that both LPOB and HPOB have significant hydrophobic properties, making them suitable stabilizers. Notably, HPOB exhibited the highest level of hydrophobic stability at pH 11.0.

[0152] 8. 3D printing accuracy test method:

[0153] 3D printing was performed using a FoodBot S2 printer (Hangzhou Shiyin Technology Co., Ltd., Hangzhou, China). The loaded material barrel was inserted into the 3D printer. The printing temperature was set to 25 °C, the printing speed was set to 35 mm / s, the nozzle diameter was set to 1.2 mm, and the material extrusion speed was set to 100%. A cylinder with a diameter of 8 mm and a height of 10 mm and a heart with a diameter of 10 mm and a height of 5 mm were printed. The printed appearance is shown in the figure. Fig. 9The 3D printed models were visually observed and recorded through photos. In addition, a vernier caliper was used to measure the diameter and height of different sample groups to calculate the printing deviation. The printing deviation was calculated according to the following formula:

[0154] Printing deviation (%) = (|DD A |) / D A ×100

[0155] Where D is the diameter (height) of the measurement, mm; D A is the diameter (height) of the model, in mm, and the test results are shown in Fig.10 .

[0156] Depend on Fig. 9 It can be seen that the LPOB and HPOB formed under different pH regulation can be extruded smoothly and have a certain degree of self-supporting ability. Among them, HPOB-11.0 shows better 3D printing potential and successfully prints heart-shaped and cylindrical shapes with relatively stable structures. LPOB and HPOB can be used for relatively simple printing models, such as heart shapes, and both show good printing performance. However, when printing more three-dimensional structures (such as cylinders), both LPOB-7.0 and HPOB-7.0 show printing collapse, which indicates that maintaining a highly three-dimensional structure is more related to the self-supporting ability of the oil.

[0157] An ideal ink for 3D printing should maintain high fidelity of the printed shape, extrude smoothly without compression deformation during printing, and adhere to previously deposited layers. These properties are closely related to the rheological properties of the ink. The storage modulus G' reflects the mechanical strength of the material, which is essential for supporting and maintaining the structure of previously printed layers. Higher G' means improved printing accuracy and layer resolution, as well as improved stability and shape retention of the printed object. In addition, appropriate shear thinning behavior facilitates the extrusion and deposition of materials from a fine diameter printing nozzle during 3D printing.

[0158] The integrity of the printed shape and the clarity of the printed layer reflect the printability of the ink. The bottom of the cylinder LPOB-7.0, LPOB-9.0, HPOB-7.0, and HPOB-9.0 all showed a spreading trend, with some collapse in the line and slight series connection in the tight line. The inks of HPOB-11.0 and LPOB-11.0 had continuous filaments, smooth surfaces, clear edges, and precise geometries, indicating good printing stability.

[0159] like Fig.10As shown in the figure, under the same pH conditions, the printing deviation of HPOB is smaller than that of LPOB, and the printing deviations of LPOB and HPOB gradually decrease with the increase of pH. This indicates that the structure of the oil emulsion can be changed by adjusting the interface layer of the oil body through pH, ​​thereby improving the high mechanical strength, strong shear thinning and self-supporting properties of the 3D printing ink.

[0160] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0161] The above is a detailed introduction to a peanut oil body and a preparation method thereof provided by the present invention. Specific examples are used herein to illustrate the principle and implementation method of the present invention, and the description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing peanut oil-based 3D printing ink, characterized in that: The preparation method comprises the following steps: S1. Preparation of peanut slurry The peanuts are selected, soaked, peeled, washed, mixed with water, pulped, and filtered to obtain peanut pulp; S2. Post-treatment of peanut slurry Using a pH regulator to adjust the pH of the peanut slurry to 7-11 to obtain a treated peanut slurry; S3. Preparation of Peanut Oil Bodies Centrifuging the treated peanut slurry and taking the upper white enriched matter to obtain peanut oil bodies; S4. Preparation of peanut oil-based 3D printing ink The peanut oil body is placed at a temperature of 4° C. and kept stable for 6-12 hours to obtain a peanut oil body-based 3D printing ink.

2. The preparation method according to claim 1, characterized in that: In step S1, the specific conditions of the soaking are: soaking temperature 4°C, soaking time 16-20h.

3. The preparation method according to claim 1, characterized in that: In step S2, the pH adjuster is an alkaline pH adjuster, and the pH adjuster is selected from KOH, NaOH or NaHCO3.

4. The preparation method according to claim 1, characterized in that: In step S3, the specific conditions of the centrifugation are: centrifugal speed 4000-10000 rpm, and centrifugal time 15-30 min.

5. The preparation method according to claim 1, characterized in that: In step S1, the mass volume ratio of the washed peanuts to water is 1:6-10 (kg / L).

6. The preparation method according to claim 1, characterized in that: The peanuts are high oleic peanuts.

7. The preparation method according to claim 1, characterized in that: In step S2, the pH of the peanut slurry is adjusted to 11.

8. A peanut oil body-based 3D printing ink prepared by the preparation method according to claim 1.

9. A use of the peanut oil-based 3D printing ink as claimed in claim 8 in 3D printing, characterized in that: The oleic acid content in the peanut oil is 80-85%.

10. The use of the peanut oil-based 3D printing ink in 3D printing according to claim 9, characterized in that: The parameters of the 3D printing are: printing temperature 20-25° C., printing speed 30-35 mm / s, nozzle diameter 0.84-1.2 mm, and material extrusion speed 100%.

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