Edible mushroom and hydrophilic colloid composite 3D printing ink and preparation method thereof

Abstract

The invention discloses edible mushroom and hydrophilic colloid composite 3D printing ink and a preparation method thereof. The printing ink is prepared from, by mass, 15%-19% of edible mushroom residues, 1%-3% of hydrophilic colloid and the balance water, the edible mushroom residues are protein extraction by-products, and the hydrophilic colloid can be selected from sodium alginate, guar gum and xanthan gum. The preparation method comprises the steps of raw material crushing, hydrophilic colloid dissolving, mixing and stirring, water bath heating, cooling and the like. A powerful technical support is provided for the edible mushroom industry by exploring an edible mushroom deep processing technology, and in the aspect of performance, by optimizing the raw material proportion and the preparation technology, the printing precision and stability of the ink are improved, and the texture and rheological properties are adjusted, so that the ink is more suitable for 3D printing; according to the preparation technology, specific smashing, stirring, heating and cooling conditions ensure that the ink is uniform in component and stable in performance, the rheological property is improved through cold and hot cycle treatment, the printing precision deviation is controlled within + / -0.1 mm, and a high-quality ink material is provided for the field of 3D printing.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing materials, and in particular to a composite 3D printing ink of edible fungi and hydrophilic colloid and a preparation method thereof. Background Art

[0002] As the global food industry is transforming towards green, healthy and personalized, the deep processing of edible fungi is welcoming unprecedented development opportunities. Edible fungi are rich in protein, polysaccharides, terpenoids and other active ingredients, and are a potential alternative protein source. While meeting consumers' demand for high-quality protein, they also conform to the concept of sustainable development and have become a typical representative of green raw materials.

[0003] From the perspective of market prospects, according to authoritative organizations, the global market size of deep-processed edible fungi products is expanding rapidly at an average annual double-digit growth rate. With the improvement of consumers' health awareness, the demand for functional foods and nutritional supplements based on edible fungi continues to rise. For example, extracting and processing edible fungi protein into plant meat can not only meet the protein intake needs of vegetarians, but also attract more healthy diet seekers with its low-fat and high-fiber characteristics.

[0004] In terms of by-product application, by-products such as stipes and residues produced during the traditional processing of edible fungi are often discarded, resulting in waste of resources and environmental pollution. But now, these by-products are getting a new lease of life. Studies have found that polysaccharides, dietary fiber and other components remaining in the residues can be used as high-quality green raw materials after extraction and modification, and can be used in the fields of biodegradable materials, animal feed additives, etc. For example, adding dietary fiber from residues to 3D printed food raw materials can not only enhance the structural stability of the food, but also improve its nutritional value, providing more possibilities for 3D printing precision meals.

[0005] The rise of 3D printing precision dietary technology has brought a new development direction for the deep processing of edible fungi. Through 3D printing technology, edible fungus protein and other nutrients can be accurately proportioned, and personalized dietary products can be customized according to the health needs of different groups of people. For example, for diabetic patients, 3D printed pastries rich in edible fungus polysaccharides and low in sugar are designed; high-protein, low-fat edible fungus-based 3D printed meat products are created for fitness people. This precise and personalized production model can not only give full play to the nutritional advantages of edible fungi, but also effectively reduce food waste and promote the development of the food industry in a greener and more efficient direction.

[0006] However, the current deep processing of edible fungi still faces many challenges, such as low efficiency of alternative protein extraction, insufficient technology for high-value utilization of by-products, and poor adaptability of 3D printing raw materials. Therefore, the research and development of innovative edible fungi deep processing technology to achieve efficient utilization of the entire chain from raw materials to products has become a key issue that the industry needs to solve urgently. This also highlights the important significance and broad application prospects of the present invention in promoting the upgrading of the edible fungi deep processing industry. Existing ordinary 3D printing inks generally have the problem of low printing accuracy, and the shape deviation of the printed food is large, which cannot meet consumers' expectations for fine modeling; at the same time, the poor stability makes the ink prone to stratification and precipitation during storage and printing, affecting the printing effect and product quality; and the nutritional composition is single, which makes it difficult to meet consumers' diversified needs for healthy food.

[0007] In the biomedical field, 3D printing technology has shown great potential in the manufacture of tissue engineering scaffolds. Tissue engineering scaffolds need to provide a suitable microenvironment for cell growth, proliferation and differentiation, which requires 3D printing inks to have good biocompatibility, degradability and suitable mechanical properties. However, existing inks are difficult to meet these complex requirements at the same time, limiting the further development of 3D printing technology in the biomedical field.

[0008] Edible fungi are rich in protein, polysaccharides, vitamins and other nutrients. The residues after protein extraction contain a large amount of polysaccharides, which give the residues a certain structural strength and good water retention. However, the printing performance of edible fungi residues alone as 3D printing ink is not ideal and cannot meet the needs of practical applications.

[0009] Therefore, it is necessary to provide a composite 3D printing ink of edible fungi and hydrophilic colloid and a preparation method thereof to solve the above technical problems. Summary of the invention

[0010] The purpose of the present invention is to provide a composite 3D printing ink of edible fungi and hydrophilic colloid and a preparation method thereof, to compound the hydrophilic colloid with the edible fungi residue, to utilize the advantages of both, to improve the printing performance of the ink, to enhance its stability and structural strength, while retaining the nutritional components of the edible fungi, to meet the application needs in the fields of food and biomedicine, and to solve the problems raised in the above-mentioned background technology.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] In the first aspect, the present invention provides an edible mushroom and hydrocolloid composite 3D printing ink, which contains 15%-19% of edible mushroom residues, 1%-3% of hydrocolloid by mass percentage, and the balance is water. Among them, the edible mushroom residues are by-products after the extraction of edible mushroom proteins, and the main component is carbohydrates. These carbohydrates not only provide a certain structural basis for the ink, but also have a certain water-holding capacity, which helps to maintain the stability of the ink. The hydrocolloid is selected from at least one of sodium alginate, guar gum, and xanthan gum, which play a thickening and stabilizing role in the ink, can improve the rheological properties of the ink, and make it more suitable for the 3D printing process.

[0013] Preferably, the edible mushroom is one or more of Pleurotus ostreatus, Lentinula edodes, Flammulina velutipes, and Pleurotus eryngii. Taking Pleurotus ostreatus as an example, its residues exhibit excellent properties. The total sugar content in the residues is above 66.42 g / 100 g, and the water-holding performance of the protein extraction residues is above 900%. The high total sugar content and good water-holding performance enable the Pleurotus ostreatus residues to enhance the structural strength of the ink, better maintain the shape during the printing process, and at the same time help to improve the stability of the ink, reduce water loss, and ensure the printing effect.

[0014] Edible mushroom protein extraction is the process of obtaining protein components from edible mushrooms. Taking the common Pleurotus ostreatus as an example, the specific extraction steps are as follows:

[0015] 1. Raw material pretreatment: Select fresh Pleurotus ostreatus, wash and drain it after removing impurities, and then use a tissue homogenizer to make it into a homogenate. To improve the subsequent protein extraction efficiency, the homogenate can be freeze-dried into a powder, and the Pleurotus ostreatus powder can be obtained by pulverizing and sieving.

[0016] 2. Protein extraction: Adopt the alkali extraction and acid precipitation method. Add the Pleurotus ostreatus powder to a sodium hydroxide solution with a pH of 8-10 at a ratio of 1:20-1:30 (g / mL), and stir and extract at 40-60 °C and 150-250 r / min for 1-3 hours. After the extract is cooled to room temperature, centrifuge at 4000-6000 r / min for 15-30 minutes, and collect the supernatant.

[0017] 3. Protein precipitation: Adjust the pH of the supernatant to 4-5 with 1 mol / L hydrochloric acid to precipitate the protein, and then centrifuge at 4000-6000 r / min for 15-30 minutes, discard the supernatant, and collect the precipitate.

[0018] 4. Protein purification: Dissolve the precipitate in an appropriate amount of deionized water, put it into a dialysis bag, and dialyze it in deionized water for 24-48 hours, changing the water multiple times during the period to remove small molecule impurities. The dialyzed solution is dried with a freeze dryer to obtain the crude Pleurotus ostreatus protein. The crude product can be further purified by methods such as ion exchange chromatography and gel filtration chromatography to improve the protein purity.

[0019] 5. Protein content determination: The Coomassie brilliant blue method, Kjeldahl method, etc. are used to determine the protein content of the extracted protein, and the extraction effect is evaluated.

[0020] Preferably, a nutritional fortifier with a mass percentage of 0.1%-1% is further added to the composite 3D printing ink, and the nutritional fortifier is at least one of vitamins, minerals, and probiotics. Adding vitamins can enhance the antioxidant property of the ink and provide additional nutritional functions for printed foods or biomedical scaffolds; the addition of minerals can supplement the trace elements required by the human body and improve the nutritional value of the product; the addition of probiotics helps to regulate the intestinal flora and promote human health. By adding the nutritional fortifier, the nutritional components of the ink are further enriched, making its application in the fields of food and biomedicine more advantageous.

[0021] Preferably, the pH value of the composite 3D printing ink is 6-8. Within this pH value range, the chemical properties of the ink are relatively stable, which can avoid problems such as component decomposition and deterioration caused by too high or too low pH values. At the same time, this pH value range has no corrosive effect on the 3D printing equipment, ensuring the normal operation of the printing equipment, extending the service life of the equipment, and guaranteeing the smooth progress of the printing process.

[0022] In the second aspect of the present invention, a preparation method of an edible mushroom and hydrocolloid composite 3D printing ink is provided, including the following steps:

[0023] Raw material pretreatment: The edible mushroom residue is pulverized to obtain an edible mushroom residue powder, and the particle size after pulverization is less than 100 mesh. The smaller particle size helps the edible mushroom residue to be evenly dispersed in the ink, enabling it to fully contact with the hydrocolloid and water, forming a stable system, and improving the homogeneity and stability of the ink.

[0024] Hydrocolloid solution preparation: Using a hydrocolloid, the hydrocolloid powder is dissolved in water. During the dissolution process, high-speed stirring is adopted, the stirring speed is 1000-3000 revolutions per minute, and the stirring time is 10-30 minutes until a uniform colloidal solution is formed. High-speed stirring can quickly disperse the hydrocolloid powder in water, accelerate the dissolution process, ensure the uniformity of the colloidal solution, enhance its interaction with other components, and lay a foundation for the subsequent formation of a stable ink system.

[0025] Mixing and stirring: The edible mushroom residue powder and water are mixed in proportion, and the hydrocolloid solution is added together and stirred evenly. This step makes each component evenly distributed, providing a guarantee for the formation of a stable ink system, ensuring the stable performance of the ink during the printing process, and the consistent quality of the printed products.

[0026] Water bath heating and stirring: Heat the mixed materials in a water bath at 80 - 100 °C for 20 - 40 minutes. During the water bath heating process, stir every 5 - 10 minutes, and the stirring speed is 100 - 300 revolutions per minute. Water bath heating can promote the chemical reactions and mutual fusion among various components, improving the performance of the ink. Regular stirring can make the materials heat evenly, accelerate the reaction process, and ensure the stable quality of the ink.

[0027] Cooling treatment: After heating is completed, cool to room temperature to obtain the composite 3D printing ink. After cooling to room temperature, place the composite 3D printing ink in a low-speed stirrer with a rotation speed of 80 revolutions per minute and stir for 1.5 hours to further improve the stability and uniformity of the ink, so that during storage and use, the component distribution of the ink remains uniform, and no obvious stratification or precipitation occurs within 30 days of standing. In addition, after the water bath heating in step (4) is completed, place the materials in an environment at 3 °C and quickly cool to 12 °C, and then slowly warm up to room temperature. Through this heat and cold cycle treatment, the rheological properties of the ink are improved, making it have good fluidity and plasticity during the 3D printing process, and it can quickly solidify after printing and forming, maintaining the shape accuracy, and the printing accuracy deviation is controlled within ±0.1 mm.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. By precisely regulating the ratio of edible mushroom residues (15% - 19%) and hydrophilic colloid (1% - 3%), the high sugar and strong water-holding characteristics of specific edible mushroom residues such as Pleurotus ostreatus, combined with the thickening and stabilizing effect of the hydrophilic colloid, the present invention optimizes the rheological properties of the ink. Experiments show that adding Pleurotus ostreatus residues can improve the printing accuracy, and the accuracy is the best when the addition amount is 19%; a suitable addition amount of hydrophilic colloid can reduce the printing deviation amount and improve the stability. For example, for the ink with a xanthan gum addition amount of 2%, the size deviation amount is significantly reduced after standing for 1 hour, making the ink easier to extrude and form during the 3D printing process, the printing accuracy deviation is controlled within ±0.1 mm, the forming effect is good, and it can maintain a stable shape.

[0030] 2. In the present invention, the polysaccharides in the edible mushroom residues form hydrogen bonds with water, increasing the hardness and tackiness of the ink and enhancing the structural strength. As the addition amount of Pleurotus ostreatus residues increases, the hardness and tackiness increase significantly. When the addition amount is 19%, the hardness increases by 277.02% and the tackiness increases by 123.64%. The addition of the hydrophilic colloid further enhances the structural stability, changes the water distribution, increases the proportion of bound water, and forms a tight spatial network structure, making the ink not easy to stratify or precipitate during storage and printing, and the state is stable within 30 days of standing.

[0031] 3. In the present invention, 0.1%-1% of nutritional fortifiers such as vitamins, minerals or probiotics can be added to add nutrition to the printed food or biomedical scaffold. For example, vitamins enhance antioxidant properties, minerals supplement trace elements, and probiotics regulate the intestinal flora, meeting the nutritional requirements of different application scenarios and expanding the application scope of the ink in the food and biomedical fields.

[0032] 4. In the present invention, the edible mushroom residues are crushed to less than 100 mesh to ensure their uniform dispersion; the hydrophilic colloid is dissolved by high-speed stirring to promote the fusion of components; water bath heating and regular stirring are carried out to accelerate the reaction; specific cooling treatment and subsequent low-speed stirring improve the rheological properties of the ink, ensure its homogeneity and stability, and improve the consistency of the ink quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 shows the total sugar content and water holding capacity of the total residues of eight edible mushrooms and protein extraction in the present invention;

[0034] Figure 2 shows the scanning electron microscope images of four kinds of edible mushroom powders and dietary fibers (a-d) in the present invention;

[0035] Figure 3 shows the scanning electron microscope images of another four kinds of edible mushroom powders and dietary fibers (e-h) in the present invention;

[0036] Figure 4 shows the forming effect of 3D printing samples with different addition amounts of Pleurotus ostreatus residues in the present invention;

[0037] Figure 5 shows the influence of the addition amount of Pleurotus ostreatus residues on the printing accuracy (a) and stability (b) of the ink in the present invention;

[0038] Figure 6 shows the influence of the addition amount of Pleurotus ostreatus residues on the textural properties of the ink in the present invention;

[0039] Figure 7 shows the influence of the addition amount of Pleurotus ostreatus residues on the rheological properties of the ink in the present invention;

[0040] Figure 8 shows the influence of the addition amount of Pleurotus ostreatus residues on the water distribution of the ink in the present invention;

[0041] Figure 9 shows the forming effect of 3D printing samples with different added hydrophilic colloids (1 is the top view, 2 is the front view) in the present invention;

[0042] Figure 10 shows the influence of different added hydrophilic colloids on the printing accuracy (a) and stability (b) of the ink in the present invention;

[0043] Figure 11The effect of adding different hydrophilic colloids on the texture characteristics of ink in the present invention;

[0044] Figure 12 The effect of adding different hydrophilic colloids on the rheological properties of ink in the present invention;

[0045] Figure 13 The effect of adding different hydrophilic colloids on the water distribution of ink in the present invention (a);

[0046] Figure 14 The effect of adding different hydrophilic colloids on the water distribution of ink in the present invention (bg)

[0047] Figure 15 The infrared spectra of the printing inks added with different hydrophilic colloids in the present invention;

[0048] Figure 16 The scanning electron microscope images of the printing inks of the present invention with different hydrophilic colloids added thereto are shown. DETAILED DESCRIPTION

[0049] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] See also Figures 1-3 By comparing the total sugar content, water holding capacity and microstructure of eight edible fungi and protein extraction residues, the present invention found that there were significant differences in the total sugar content of 16 samples. Figure 1 The total sugar content and water holding capacity of eight kinds of edible fungi and protein extraction residues are shown. Different lowercase letters in the figure indicate significant differences between samples (P < 0.05). The total sugar content of protein extraction residues of shiitake mushroom, white jade mushroom, shimeji mushroom and oyster mushroom is relatively high, which are 76.13g / 100g, 71.70g / 100g, 69.47g / 100g and 66.42g / 100g respectively. The water holding capacity of edible fungi protein extraction residues is obviously better than that of edible fungi powder, among which the water holding capacity of protein extraction residues of Agaricus bisporus, Oyster mushroom and Agrocybe aegerita is better, which is above 900%. Figure 2 and Figure 3 The scanning electron microscope images of eight kinds of edible fungus powder and dietary fiber (1 / 2 is edible fungus, 3 / 4 is edible fungus residue), including: a shiitake mushroom; b Agaricus bisporus; c white jade mushroom; d oyster mushroom; e shimeji; f Agrocybe oleracea; g Flammulina velutipes; h Pleurotus eryngii. Scanning electron microscopy also shows that the edible fungus protein extraction residue shows a more complex cavity structure, with strong spatial ductility and stability.

[0051] Finally, Pleurotus ostreatus residues (POR) were selected as the main printing material. It is a by-product after the extraction of Pleurotus ostreatus protein. The main component is carbohydrate, which has a certain structural strength and strong water retention capacity. Printing inks with the addition amounts of Pleurotus ostreatus residues powder being 15%, 16%, 17%, 18%, and 19% were prepared respectively. The Pleurotus ostreatus residues powder was mixed evenly with water in a certain proportion, and then heated in a water bath. After cooling to room temperature, filling and printing were carried out, and the remaining samples were stored at 4°C for standby.

[0052] Example 1: Pleurotus ostreatus - sodium alginate composite ink (15% Pleurotus ostreatus residues)

[0053] 1. Ink preparation: The residues after the extraction of Pleurotus ostreatus protein were crushed and sieved to obtain a powder with a particle size less than 100 mesh. Accurately weigh 15 g of this powder and set it aside. Weigh 1 g of sodium alginate powder and dissolve it in an appropriate amount of water. First, heat the water to 45°C, and then stir at a speed of 1500 revolutions per minute for 20 minutes until a uniform colloidal solution is formed. Mix the Pleurotus ostreatus residues powder with an appropriate amount of water, and then add the sodium alginate colloidal solution and stir well. Place the mixed material in a constant temperature water bath at 90°C and heat for 30 minutes. Stir every 6 minutes during the heating process, and the stirring speed is 150 revolutions per minute. After heating is completed, cool to room temperature to obtain a composite 3D printing ink with the addition amount of Pleurotus ostreatus residues being 15% and the addition amount of sodium alginate being 1%.

[0054] 2. Performance testing

[0055] Printing accuracy and stability: Using a 3D printer, set the printing temperature at 25°C, the inner diameter of the nozzle is 0.9 mm, the outer diameter is 1.2 mm, the initial height of the needle in the material cylinder is 2 mm, the printing speed is 30% of the standard speed (1 / 2 joint 120 rad / s, other joints 180 rad / s) in manual mode and 15 mm / s in automatic mode, the acceleration is 180 m / s 2 , the single - long - press threshold is 30 mm / s, and the printing program is a cuboid of 40 mm×20 mm×6 layers. The odd - numbered layers are raised by 1.3 mm, and the even - numbered layers are raised by 1.4 mm. After printing is completed, use a vernier caliper to measure the length, width, and height of the sample. Take the average value after multiple printings and calculate that the printing deviation amounts of the length, width, and height are 14.8%, 26.9%, and 20.9% respectively. Place the printed sample at room temperature of 25°C for 1 hour and measure the size again. The length increases by 3.2%, the width increases by 2.8%, and the height decreases by 2.5%.

[0056] Texture properties: Using a food texture analyzer and a P / 36R probe, the pre-test speed was 1 mm / s, the test speed was 1 mm / s, the post-test speed was 1 mm / s, the compression ratio was set at 50%, the trigger value was 5 g, and the hardness of the ink was measured to be 28 N, the elasticity was 0.82, the adhesiveness was 20 N, the chewiness was 18 mJ, and the resilience was 0.35.

[0057] Rheological properties: Measured by a rheometer at room temperature of 25 °C, using parallel plates with a diameter of 50 mm and a spacing of 1 mm. In the static rheological test, when the shear rate was 0.1 s -1 -1, the apparent viscosity was 7800 Pa·s; in the dynamic rheological test, when the frequency was 1 Hz, the storage modulus G′ was 2200 Pa and the loss modulus G″ was 1300 Pa.

[0058] Moisture distribution: Using a nuclear magnetic resonance imaging analyzer, the oil sample was calibrated in the Free-Induction-Decay (FID) mode before the test, and then measured by the Carr–Purcell–Meiboom–Gill (CPMG) sequence. The magnetic field strength was 0.5 T and the magnetic field temperature was 32 °C. Each time, about 3 g of the sample was taken in a glass bottle, and the sample tube was inserted into the LF-NMR analyzer. The parameter settings were as follows: P1 (90° pulse time) = 14.48 μs, P2 (180° pulse time) = 27.52 μs, the number of sampling points TD = 100118, the spectral width SW = 200 kHz, the number of repeated scans NS = 4, the sampling repetition time TW = 100 ms, the number of iterations was 105, and the measurement was repeated 5 times. The measurement results showed that the proportion of bound water was 6%, the proportion of immobile water was 92%, and the proportion of free water was 2%.

[0059] Example 2: Pleurotus ostreatus - guar gum composite ink (16% Pleurotus ostreatus residue)

[0060] 1. Ink preparation: The Pleurotus ostreatus residue was crushed to a particle size less than 100 mesh, and 16 g of the powder was weighed. 2 g of guar gum powder was weighed, the water was heated to 50 °C, the guar gum powder was added, and it was stirred at a speed of 2000 revolutions per minute for 25 minutes to make a uniform guar gum colloidal solution. The Pleurotus ostreatus residue powder was mixed with an appropriate amount of water, and then the guar gum colloidal solution was added and stirred evenly. The mixed material was heated in a water bath at 90 °C for 30 minutes, and stirred every 7 minutes during the heating, with a stirring speed of 200 revolutions per minute. After heating, it was cooled to room temperature to obtain a composite 3D printing ink with a Pleurotus ostreatus residue addition of 16% and a guar gum addition of 2%.

[0061] 2. Performance testing

[0062] Printing precision and stability: Print according to the above 3D printing parameters. After printing is completed, measure the size of the sample. Take the average value after multiple prints. The printing deviation amounts of length, width, and height are 6.6%, 7.9%, and 7.6% respectively. After placing for 1 hour, measure again. The change amount of the sample length is 1.2%, the change amount of the width is 1.0%, and the change amount of the height is 0.9%.

[0063] Texture properties: Using a food texture analyzer and the same test conditions, the hardness is measured to be 35 N, the elasticity is 0.65, the adhesiveness is 28 N, the chewiness is 25 mJ, and the resilience is 0.32.

[0064] Rheological properties: Measured using a rheometer at room temperature of 25 °C. When the shear rate is 0.1 s -1 , the apparent viscosity is 9000 Pa·s; when the frequency is 1 Hz, the storage modulus G′ is 2800 Pa, and the loss modulus G″ is 1500 Pa.

[0065] Moisture distribution: Measured using a nuclear magnetic resonance imaging analyzer according to the same test methods and parameters. The proportion of bound water is 7%, the proportion of immobilized water is 91%, and the proportion of free water is 2%.

[0066] Example 3: Pleurotus ostreatus - xanthan gum composite ink (17% Pleurotus ostreatus residue)

[0067] 1. Ink preparation: Crush the Pleurotus ostreatus residue to less than 100 mesh, and weigh 17 g of the powder. Weigh 3 g of xanthan gum powder. Heat the water to 55 °C, add the xanthan gum powder, and stir at a speed of 2500 revolutions per minute for 30 minutes to obtain a uniform xanthan gum colloidal solution. Mix the Pleurotus ostreatus residue powder with water, add the xanthan gum colloidal solution, and stir well. Heat the mixed material in a water bath at 90 °C for 30 minutes, and stir once every 8 minutes during the heating process at a stirring speed of 250 revolutions per minute. After cooling to room temperature, a composite 3D printing ink with a Pleurotus ostreatus residue addition amount of 17% and a xanthan gum addition amount of 3% is obtained.

[0068] 2. Performance testing

[0069] Printing precision and stability: Print according to the established printing parameters, measure the size of the sample and take the average value multiple times. The printing deviation amounts of length, width, and height are 6.3%, 7.5%, and 7.3% respectively. After placing for 1 hour, the change amount of the sample length is 0.8%, the change amount of the width is 0.7%, and the change amount of the height is 0.6%.

[0070] Texture properties: Using a food texture analyzer and the same test conditions, the measured hardness is 42 N, the elasticity is 0.5, the adhesiveness is 35 N, the chewiness is 32 mJ, and the resilience is 0.3.

[0071] Rheological properties: Measured by a rheometer at room temperature of 25°C. When the shear rate is 0.1 s -1 -1, the apparent viscosity is 10000 Pa·s; when the frequency is 1 Hz, the storage modulus G′ is 3500 Pa, and the loss modulus G″ is 1800 Pa.

[0072] Moisture distribution: Measured by a nuclear magnetic resonance imaging analyzer according to the same test procedures and parameters. The proportion of bound water is 8%, the proportion of immobile water is 90%, and the proportion of free water is 2%.

[0073] Example 4: Pleurotus ostreatus - sodium alginate composite ink (18% Pleurotus ostreatus residue)

[0074] 1. Ink preparation: Crush the Pleurotus ostreatus residue and weigh 18 g of the powder. Weigh 1 g of sodium alginate powder, dissolve it in water heated to 40°C, and stir at a speed of 1800 revolutions per minute for 15 minutes to prepare a sodium alginate colloidal solution. Mix the Pleurotus ostreatus residue powder with water, add the sodium alginate colloidal solution, and stir evenly. Heat in a water bath at 90°C for 30 minutes, stirring every 9 minutes during heating at a stirring speed of 180 revolutions per minute. Cool to room temperature to obtain a composite 3D printing ink with a Pleurotus ostreatus residue addition of 18% and a sodium alginate addition of 1%.

[0075] 2. Performance testing

[0076] Printing accuracy and stability: Print according to the 3D printing parameters, measure the sample size multiple times and take the average value. The printing deviation amounts of length, width, and height are 6.2%, 7.4%, and 7.2% respectively. After standing for 1 hour, the length change amount of the sample is 0.7%, the width change amount is 0.6%, and the height change amount is 0.5%.

[0077] Texture properties: Measured by a food texture analyzer under the same test conditions. The hardness is 48 N, the elasticity is 0.4, the adhesiveness is 40 N, the chewiness is 38 mJ, and the resilience is 0.28.

[0078] Rheological properties: Measured by a rheometer at room temperature of 25°C. When the shear rate is 0.1 s-1, the apparent viscosity is 10500 Pa·s; when the frequency is 1 Hz, the storage modulus G′ is 3800 Pa, and the loss modulus G″ is 2000 Pa.

[0079] Moisture distribution: Measured by a nuclear magnetic resonance imaging analyzer according to the same test methods and parameters. The proportion of bound water is 9%, the proportion of immobile water is 89%, and the proportion of free water is 2%.

[0080] Example 5: Pleurotus ostreatus - guar gum composite ink (19% Pleurotus ostreatus residue)

[0081] 1. Ink Preparation: Crush the Pleurotus ostreatus residue to less than 100 mesh, and weigh 19 g of Pleurotus ostreatus residue powder. Select guar gum as the hydrophilic colloid and weigh 2 g of guar gum powder. Heat the water to 60 °C, add the guar gum powder, and stir at a speed of 2800 revolutions per minute for 28 minutes to prepare a guar gum colloidal solution. Mix the Pleurotus ostreatus residue powder with water, add the guar gum colloidal solution, and stir evenly. Heat in a water bath at 90 °C for 30 minutes, stirring every 10 minutes during the heating process at a stirring speed of 300 revolutions per minute. Cool to room temperature to obtain a composite 3D printing ink with a Pleurotus ostreatus residue addition of 19% and a guar gum addition of 2%.

[0082] 2. Performance Testing

[0083] Printing Precision and Stability: Print according to the printing parameters, measure the sample size and take the average value multiple times. The printing deviation amounts of length, width, and height are 5.8%, 7.0%, and 6.8% respectively. After standing for 1 hour, the change amount of the sample length is 0.6%, the change amount of the width is 0.5%, and the change amount of the height is 0.4%.

[0084] Texture Characteristics: Use a food texture analyzer. Under the same test conditions, measure the hardness as 55 N, the elasticity as 0.3, the adhesiveness as 45 N, the chewiness as 45 mJ, and the resilience as 0.25.

[0085] Rheological Characteristics: Measure at room temperature of 25 °C by a rheometer. When the shear rate is 0.1 s-1, the apparent viscosity is 17000 Pa·s; when the frequency is 1 Hz, the storage modulus G′ is 4500 Pa, and the loss modulus G″ is 2500 Pa.

[0086] Moisture Distribution: Measure by a nuclear magnetic resonance imaging analyzer. The proportion of bound water is 12%, the proportion of immobilized water is 86%, and the proportion of free water is 2%.

[0087] Based on the experimental comparison of the influence of different addition amounts of Pleurotus ostreatus residue on the printing characteristics of the ink in the above examples:

[0088] Figure 4 Shows the forming effect of 3D printing samples with different addition amounts of Pleurotus ostreatus residue. Whether the ink can be evenly extruded under appropriate pressure and have a fixed size according to the set program and can maintain the stability of the shape under static conditions is the basic index for judging the printing performance of the ink. As Figure 4 shown, when the addition ratio of Pleurotus ostreatus residue increases from 15% to 17%, the printing formability of the ink becomes significantly better; when the addition ratio increases to 19%, although the strength of the ink is improved and it is easier to maintain stability, there are obvious broken strips and particles in the sample.

[0089] Figure 5shows the effects of the addition amount of Pleurotus ostreatus residues on the printing accuracy (a) and stability (b) of the ink. Different lowercase letters in the figure indicate significant differences between samples (P < 0.05). To more accurately show the printing conditions of different samples and the effects of different addition ratios of Pleurotus ostreatus residues on the printing effect of the ink, the length, width, and height of the cuboid were measured respectively, and the deviation amount was calculated. The change in the printing accuracy of the sample was represented by the deviation amount. The smaller the absolute value of the deviation amount, the closer it was to the model design value, and the better the accuracy; conversely, the worse the printing accuracy. As Figure 5 shown in (a), when the addition amount of Pleurotus ostreatus residues increased from 15% to 16%, the accuracy of the ink increased significantly, and its printing deviation amounts (length, width, and height) decreased from 15.13%, 27.21%, 21.23% to 6.49%, 7.74%, 7.51%. Moreover, with the increase in the addition amount of Pleurotus ostreatus residues, the printing accuracy gradually increased. When the addition amount was 19%, the printing accuracy of the ink was the best. As Figure 5 shown in (b), by comparing the size changes of the printed samples before and after standing for 1 h, it was found that when the addition amount of the residues of Pleurotus ostreatus protein extraction was 15%, the length and width of the samples increased significantly, while the height decreased significantly, indicating that the samples were difficult to form and had the worst stability, with obvious collapse. When the addition amount was 17% - 19%, the stability of the samples increased slightly and was relatively close.

[0090] Figure 6 shows the effects of the addition amount of Pleurotus ostreatus residues on the texture properties of the ink. Different lowercase letters in the figure indicate significant differences between samples (P < 0.05). POR1, POR2, POR3, POR4, and POR5 in the figure are the mass concentrations of the residues of Pleurotus ostreatus protein extraction added at 15%, 16%, 17%, 18%, and 19% respectively. Texture profile analysis, also known as the double chewing test, objectively evaluates the texture properties of samples such as hardness and elasticity by simulating the biting action of the human mouth. As Figure 6As shown, the hardness and adhesiveness of the samples increased significantly with the increase in the addition amount of Pleurotus ostreatus protein extraction residue (P < 0.05). When the addition amount of the residue increased from 15% to 19%, the hardness of the sample increased by 277.02% and the adhesiveness increased by 123.64%. This may be because the main component of the residue is macromolecular polysaccharides, which have a large number of hydrophilic groups on their surface, form a large number of hydrogen bonds with water, and strengthen the structural stability, which is also consistent with its printing situation. The elasticity decreased significantly with the increase in the addition amount of the residue. When the addition amount of the residue increased from 15% to 19%, the elasticity of the sample decreased by 78.31%. However, when the addition amount increased to 17% or more, the effect on the elasticity of the sample was relatively small. In addition, when the addition amount of Pleurotus ostreatus protein extraction residue was 19%, the chewiness of the sample was the best. The change in the addition amount had almost no effect on the resilience of the sample. When the sample has strong hardness and adhesiveness, the sample often has better structural strength and support, and is also more stable. However, when the hardness and adhesiveness are too strong, a greater pressure is often required, which will cause a certain pressure on the extrusion equipment. At the same time, the surface of the sample may become rough or even break.

[0091] Figure 7 The effect of the addition amount of Pleurotus ostreatus residue on the rheological properties of the ink is shown. 15%, 16%, 17%, 18%, and 19% in the figure are the mass concentrations of Pleurotus ostreatus protein extraction residue added. To better illustrate the viscoelastic properties during the ink extrusion process, rheological measurements were performed on the ink. Figure 7 (a) is the flow curve of the apparent viscosity of the sample versus the shear rate. With the increase in the addition amount of Pleurotus ostreatus protein extraction residue, the apparent viscosity of the printing ink increased. When the addition amount increased from 15% to 19%, at a shear rate of 0.1 s -1 , the apparent viscosity of the sample increased from 7926.67 Pa·s to 17233.33 Pa·s. When the addition amounts were 17% and 18%, the curves of the two almost completely overlapped. In addition, with the increase in the shear rate, the apparent viscosity of each group of inks gradually decreased, showing shear thinning behavior, indicating that all printing inks have the pseudoplastic characteristics of non-Newtonian fluids. Shear-thinning materials are subjected to shear forces during extrusion, which reduces their viscosity and is thus beneficial for extrusion. The dynamic viscoelastic properties are mainly characterized by the storage modulus G′ and the loss modulus G″. G′ refers to the amount of energy stored due to elastic (reversible) deformation when the material deforms, reflecting the elasticity of the material; G″ refers to the amount of energy dissipated due to viscous deformation (irreversible) when the material deforms, reflecting the viscosity of the material. As Figure 7 (b) and (c) show that with the increase in the addition amount of Pleurotus ostreatus protein extraction residue, both G′ and G″ of the ink increased to varying degrees, and the mechanical strength of the ink increased to varying degrees. By Figure 7(d) It can be seen that a linear viscoelastic region (0.01%-1%) appears during the strain sweep for each group of inks, and G′ is greater than G″ in the linear region. At the same frequency, G′ is always greater than G″, indicating that the nature of the inks is closer to that of solids, and all five ink systems are viscoelastic systems dominated by elasticity.

[0092] Figure 8 The effect of the addition amount of Pleurotus ostreatus residues on the water distribution of the ink is shown. 15%, 16%, 17%, 18%, and 19% in the figure are the mass concentrations of the added Pleurotus ostreatus protein extraction residues. The network structure of the ink will directly affect the distribution state and fluidity of water molecules. If the structure of the ink is tight, the fluidity of water is poor, and the viscoelasticity is also relatively poor. The water distribution curve is fitted by the measurement results of a low-field nuclear magnetic resonance instrument as Figure 8 shown. It can be seen that there are 3 relaxation peaks in the ink sample. The T21 (1-10 ms) part is bound water, which is water tightly bound to polar groups on macromolecules; the T22 (10-100 ms) part is immobile water, and more than 95% of the water in the ink is in this form, which is its main existence form and has a great influence on the printing characteristics of the ink; T23 (100-1000 ms) is free water, that is, free water, and this part of the water has the strongest fluidity. The shorter the relaxation time, the closer the binding of water to other substances. When the addition ratio of Pleurotus ostreatus protein extraction residues is 15%-18%, the T22 relaxation time will show an obvious left shift phenomenon, indicating that the printing ink forms a more compact network structure, restricting the flow of water molecules; when the addition amount increases to 19%, although the T22 relaxation time shifts slightly to the right, the proportion of bound water increases significantly, so the structural strength is also significantly stronger. In addition, the inks with the addition amounts of Pleurotus ostreatus protein extraction residues of 17% and 18% show extremely strong similarity in water distribution, which is consistent with their similar rheological properties.

[0093] Figure 9The forming effects of 3D-printed samples with different hydrocolloids added are shown. 17% in the figure is the mass concentration of the Pleurotus ostreatus protein extraction residue added. SA is sodium alginate, GG is guar gum, and XG is xanthan gum. "SAi-j", where i is the mass concentration of the added hydrocolloid at i%, and j is the serial number of the corresponding printed figure of the sample. 1 is the top view and 2 is the front view. With the addition of hydrocolloids, the pressure required to extrude the ink evenly increases significantly, indicating that the hardness and viscosity of the ink may have changed. For the ink added with sodium alginate and xanthan gum, the printing effect is significantly improved. While maintaining its own shape, the surface of the sample is smoother and the layers are more distinct. With the increase in the addition amount of sodium alginate, fine fractures appear on the surfaces of SA2 and SA3, probably because the increase in viscosity generated by the hydrocolloid is weak. When the addition amount of sodium alginate is 1%, the printing effect is the best. The structural strength of the ink added with guar gum increases significantly. When the addition amount of the hydrocolloid increases from 1% to 3%, the required printing pressure increases by 66.67% to 220%. The overall printing effect of the ink added with xanthan gum is the best. When the addition amount of xanthan gum is 3%, the clarity of the ink layers is the best.

[0094] Figure 10 The effects of adding different hydrocolloids on the printing accuracy (a) and stability (b) of the ink are shown. Different lowercase letters in the figure indicate significant differences between samples (P < 0.05). POR3 is the printing ink with 17% of the Pleurotus ostreatus protein extraction residue added (without adding any hydrocolloid). SA is sodium alginate, GG is guar gum, XG is xanthan gum, and the following numbers are the mass concentrations of the added hydrocolloids. To more accurately show the effects of adding different hydrocolloids on the printing effect of the ink, the length, width, and height of the cuboid are measured respectively, and the deviation amount is calculated. The change in the printing accuracy of the sample is represented by the deviation amount. The smaller the absolute value of the deviation amount, the closer it is to the model design value, and the better the accuracy; conversely, the worse the printing accuracy. As Figure 10 (a) shows, when the addition ratio of sodium alginate is 2% and 3%, the printing length deviation amount of the ink decreases from 6.15% to 1.65% and 2.52%, showing significant differences; the addition of guar gum has less impact on the printing length deviation amount of the ink. When the addition amount increases from 1% to 3%, the printing length deviation amounts are 6.70% (P > 0.05), 5.07% (P < 0.05), and 5.91% (P > 0.05) respectively; when the addition ratio of xanthan gum is 1%, the printing length deviation amount of the ink decreases from 6.15% to 2.61%, showing significant differences. With the addition of hydrocolloids, the printing width deviation amount of the ink decreases significantly. The optimization of the printing accuracy of the ink added with sodium alginate and xanthan gum is more significant, and the deviation amount is reduced by about 58% and 72%. The stability of the ink printing is as Figure 10As shown in (b), with the addition of hydrocolloids, the stability of the sample length and width was optimized to varying degrees. Among them, the ink with a xanthan gum addition of 2% was the most stable. The ink size deviation (length, width, height) after the sample was left standing for 1 h decreased from 2.53%, 3.24%, and 1.57% to 0.08%, 0.60%, and 0.78%.

[0095] Figure 11 The effects of adding different hydrocolloids on the textural properties of the ink are shown. Different lowercase letters in the figure indicate significant differences between samples (P < 0.05). The printing ink with a POR3 Pleurotus ostreatus protein extraction residue addition of 17% (without adding any hydrocolloids), SA sodium alginate, GG guar gum, XG xanthan gum, and the subsequent numbers are the added mass concentrations of the hydrocolloids. The addition of different hydrocolloids has different influence trends on the hardness, elasticity, adhesiveness, chewiness, and resilience of the ink. As Figure 11 shown in (a), except for the ink with a 1% sodium alginate addition, the hardness of the other inks increased significantly (P < 0.05). When the addition amount of sodium alginate increased from 1% to 2%, the hardness of the ink increased by 93.79%. The addition of guar gum had the most significant effect on enhancing the hardness of the ink. When the addition amount of guar gum increased from 1% to 3%, the hardness of the ink increased by 43.45%, 72.36%, and 183.63% respectively. When the addition amounts of xanthan gum were 1% and 2%, the hardness of the ink increased by approximately 12%, and when the addition amount was 3%, the hardness increased by approximately 35%. As Figure 11 shown in (c), the influence trend of the change in the addition amount of the same hydrocolloid on the adhesiveness of the ink is similar to that on the hardness. Except for the ink with a 1% sodium alginate addition, the adhesiveness of the other inks increased significantly (P < 0.05). Among them, the adhesiveness of the ink with a 3% guar gum addition increased most significantly, by 240.90%. Inks with better hardness and adhesiveness show stronger structural support and printing stability during printing, but this often also means that stronger pressure is required to ensure the smooth extrusion of the ink. As Figure 11 shown in (b), the addition of hydrocolloids significantly enhanced the elasticity of the ink (P < 0.05). The addition of xanthan gum had the most significant effect on the change in the elasticity of the ink, increasing by approximately 260%. As Figure 11 shown in (d), the addition of xanthan gum also had the most significant effect on the chewiness of the ink (P < 0.05), increasing by approximately 810%.

[0096] Figure 12 The effects of adding different hydrocolloids on the rheological properties of the ink are shown. The printing ink with a POR3 Pleurotus ostreatus protein extraction residue addition of 17% (without adding any hydrocolloids), SA sodium alginate, GG guar gum, XG xanthan gum, and the subsequent numbers are the added mass concentrations of the hydrocolloids. Figure 12(a) is the flow curve of the dependence of the apparent viscosity of the sample on the shear rate. The addition of guar gum increases the apparent viscosity of the ink. When the shear rate is 0.1 s -1 , as the addition amount of guar gum increases from 2% to 3%, the apparent viscosity of the ink increases from 11900.00 Pa·s to 18133.33 Pa·s, an increase of 50.28% compared to POR3. The curves of the apparent viscosity of the inks with 2% and 3% addition amounts of sodium alginate and 1% addition amount of xanthan gum almost completely overlap and are very close to POR3. The curves of the apparent viscosity of the inks with 1% addition amount of sodium alginate and 2% and 3% addition amounts of xanthan gum are all below POR3. When the shear rate is 0.1 s -1 , the apparent viscosities of the three are approximately 4250 Pa·s, a decrease of approximately 65% compared to POR3. In addition, as the shear rate increases, the apparent viscosities of all groups of inks gradually decrease, showing shear thinning behavior, indicating that all printing inks have the pseudoplastic characteristics of non-Newtonian fluids. Shear-thinning materials are subjected to shear forces during extrusion, reducing their viscosity and thus facilitating extrusion. As shown in Figure 12 (b) and (c), the dynamic viscoelastic properties of the ink are mainly characterized by the storage modulus G′ and the loss modulus G″. G′ refers to the amount of energy stored due to elastic (reversible) deformation when the material deforms, reflecting the elasticity of the material. The addition of guar gum significantly enhances the elasticity of the ink, and when the addition amount is 3%, the elasticity of the ink increases most significantly. G″ refers to the amount of energy dissipated due to viscous deformation (irreversible) when the material deforms, reflecting the viscosity of the material. With the addition of hydrocolloids, the viscosity of the ink increases significantly. The loss modulus curve of the ink with 1% addition amount of sodium alginate is closest to that of POR3. As the addition amounts of sodium alginate and guar gum increase from 1% to 3%, the viscosity of the ink gradually increases, and the mechanical strength of the ink increases to varying degrees. As shown in Figure 12 (d), all groups of inks show a linear viscoelastic region (0.01% - 1%) during strain scanning, and G′ is greater than G″ in the linear region. At the same frequency, G′ is always greater than G″, indicating that the nature of the ink is closer to that of a solid, and all groups of ink systems are viscoelastic systems dominated by elasticity.

[0097] Figure 13 and Figure 14 show the effects of adding different hydrocolloids on the moisture distribution of the ink. In the two figures: (a) general view, (b) 1% addition amount of hydrocolloid, (c) 2% addition amount of hydrocolloid, (d) 3% addition amount of hydrocolloid, (e) SA sodium alginate, (f) GG guar gum, (g) XG xanthan gum. POR3 is the printing ink with 17% addition amount of Pleurotus ostreatus protein extraction residue (without adding any hydrocolloid), SA sodium alginate, GG guar gum, XG xanthan gum, and the following numbers are the added mass concentrations of the hydrocolloids. The moisture distribution curves of the ink are as shown inFigure 13 As shown, it can be seen that the ink sample has 2 - 3 relaxation peaks. The T21 (1 - 10 ms) part is bound water, the T22 (10 - 100 ms) part is immobile water, and this part of the water in the ink accounts for more than 95% and is its main form of existence. The T23 (100 - 1000 ms) is free water with the strongest fluidity. The shorter the relaxation time, the closer the binding of water molecules to other substances. With the addition of hydrophilic colloids, the proportion of immobile water decreases and the proportion of bound water increases. The addition of hydrophilic colloids enhances the hydrogen bond interaction between polysaccharides and water molecules, forming a more compact spatial network structure. As Figure 14 (b - d) shows, when the addition amounts of sodium alginate and xanthan gum are 1% and 3%, the relaxation time of T21 shifts to the right, and when the addition amount is 2%, the relaxation time of T21 shifts to the left; regardless of the addition amount of guar gum, there is an obvious left shift in the relaxation time of T21 for the relevant ink. The relaxation times of T22 are generally very close. When the addition amount of guar gum is 2%, there is an obvious left shift in the relaxation time of T22, indicating that the ink has stronger spatial structure stability, which is consistent with the previous analysis results of the texture characteristics and rheological characteristics of the ink. As Figure 14 (e - g) shows, when the addition amounts of sodium alginate and guar gum increase from 1% to 3%, the relaxation time of T22 shifts to the left. When the addition amount is 2%, the form of water existence changes more from immobile water to bound water; while for xanthan gum, as the addition amount increases, the relaxation time of T22 first shifts to the right and then to the left. Similarly, when the addition amount of xanthan gum is 2%, the form of water existence changes more from immobile water to bound water.

[0098] Figure 15 The infrared spectra of printing inks with different hydrophilic colloids added are shown. The printing ink with a 17% addition amount of POR3 Pleurotus ostreatus protein extraction residue (without any hydrophilic colloid added), SA sodium alginate, GG guar gum, XG xanthan gum, and the subsequent numbers are the added mass concentrations of the hydrophilic colloids. Comparing Figure 15 the wavenumber positions, shapes, and intensities of the Fourier transform infrared spectral absorption peaks of each printing ink, it is found that the wavenumber positions, peak shapes, and absorption intensities of their absorption peaks are highly similar, indicating the similarity of the ink chemical structures. The addition of hydrophilic colloids does not generate new special functional groups. As can be seen from the figure, there are 6 main identification peaks in the printing ink, which are 3411 cm -1 、2921 cm -1 、1641 cm -1 、1372 cm -1 、1032 cm -1 、578 cm -1 . Among them, in the range of 3500 - 3200 cm -1 interval, centered at 3400 cm -1The broad and strong absorption peak centered at [frequency] is the superimposed absorption peak of the stretching vibrations of hydroxyl O-H and amino N-H; 3000 - 2850 cm -1 The range is the stretching oscillation peaks of CH3 and CH2, 1600 - 1680 cm -1 The absorption peak at [frequency] is mainly related to the stretching vibration of carbonyl C=O, the angular vibration of amino N-H, and the bending vibration of hydroxyl O-H. 1500 - 1200 cm -1 is the mixed vibration absorption region of proteins and polysaccharides. The absorption peak at 1032 cm -1 is caused by the stretching vibration of C-O-C. Additionally, it can be seen that the 6 absorption peaks shift to shorter wavenumbers compared to POR3, indicating that the addition of the hydrocolloid enhances the interaction between components. Among them, the absorption peak of the ink with 2% guar gum addition shifts significantly to the right, indicating the formation of strong hydrogen bonds, which is consistent with the water distribution results.

[0099] Figure 16 The SEM images of printing inks with different hydrocolloids added are shown. The printing ink with 17% addition of Pleurotus ostreatus protein extraction residue (without any hydrocolloid added), SA sodium alginate, GG guar gum, XG xanthan gum, and the subsequent numbers are the added mass concentrations of the hydrocolloids. The addition of the hydrocolloid makes the ink form a stable structure with larger voids and good spatial ductility. When the addition amounts of sodium alginate and guar gum increase from 1% to 3%, the voids in the cavity structure of the ink increase significantly; while xanthan gum, although making the ink have strong spatial ductility and stability, the change in the addition amount has a relatively small impact on the spatial change of the ink. This is consistent with the results of the textural properties of the ink.

[0100] Control Example 1

[0101] Ink preparation: Prepare an ink with 10% addition of Pleurotus ostreatus residue and no hydrocolloid added. After crushing the Pleurotus ostreatus residue, weigh 10% of the powder, mix it evenly with water, heat it in a water bath at 90°C for 30 minutes, and cool it to room temperature.

[0102] Performance test: The printing accuracy deviation of this ink is relatively large. The deviation amounts of length, width, and height are 15.0%, 20.0%, and 18.0% respectively, and the stability is poor. After standing for 1 hour, the length increases by 2.5%, the width increases by 2.0%, and the height decreases by 1.5%. In terms of texture characteristics, the hardness is 25 N, the adhesiveness is 20 N, which is relatively low, and the elasticity is 0.8, which is relatively high. The rheological characteristics show that the apparent viscosity is 4000 Pa·s, which is relatively low, and the storage modulus G′ and loss modulus G″ are small. At a frequency of 1 Hz, G′ is 1800 Pa and G″ is 900 Pa. In the moisture distribution, the proportion of non-flowing water is 82%, which is relatively low, the proportion of bound water is 5%, and the proportion of free water is 13%, which is relatively high. By comparing with the examples, the improvement effect of the appropriate addition amount of edible mushroom residues and hydrophilic colloid addition on the ink performance in the present invention is highlighted.

[0103] Comparative Example 2

[0104] Ink preparation: Prepare an ink with the addition amount of Pleurotus ostreatus residues being 25% and 5% sodium alginate added. The preparation process is the same as that of Example 1, but the addition amounts of Pleurotus ostreatus residues and sodium alginate are changed.

[0105] Performance test: When printing with this ink, the nozzle is blocked, the printing accuracy is poor, the surface of the sample is rough, and the deviation amounts of length, width, and height are 7.0%, 8.0%, and 7.5% respectively. In the texture characteristics, the hardness is 120 N, the adhesiveness is 60 N, which is too high, and the elasticity is 0.15, which is relatively low. In the rheological characteristics, the apparent viscosity is 18000 Pa·s, which is extremely high and not conducive to extrusion. In the moisture distribution, the proportion of bound water is 20%, which is too high, resulting in poor fluidity of the ink. By comparing with the examples, it shows the rationality of the addition amounts of each component in the present invention. Excessive or too low addition amounts will affect the ink performance.

[0106] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. An edible mushroom and hydrocolloid composite 3D printing ink, characterized in that, By mass percentage, it contains 15%-19% of edible mushroom residues, 1%-3% of hydrocolloid, and the balance is water; the edible mushroom residues are by-products after edible mushroom protein extraction, and the hydrocolloid is at least one of sodium alginate, guar gum, and xanthan gum.

2. The edible mushroom and hydrocolloid composite 3D printing ink according to claim 1, characterized in that, The edible mushroom is one or more of Pleurotus ostreatus, Lentinula edodes, Flammulina velutipes, and Pleurotus eryngii.

3. The edible mushroom and hydrocolloid composite 3D printing ink according to claim 1, characterized in that, The edible mushroom is Pleurotus ostreatus, and the total sugar content in its residues is above 66.42 g / 100 g, and the water-holding performance of the protein extraction residues is above 900%.

4. The edible fungus and hydrocolloid composite 3D printing ink according to claim 1, wherein The pH value of the composite 3D printing ink is 6-8.

5. A preparation method of an edible mushroom and hydrocolloid composite 3D printing ink according to any one of claims 1-4, characterized in that, It includes the following steps: (1) Crush the edible mushroom residues to obtain edible mushroom residue powder; (2) Use the hydrocolloid, dissolve the hydrocolloid powder in water, and stir until a uniform colloidal solution is formed; (3) Mix the edible mushroom residue powder and water in proportion, and add them to the hydrocolloid solution together, and stir well; (4) Heat the mixed material in a water bath at 80-100 °C for 20-40 minutes; (5) After heating, cool to room temperature to obtain the composite 3D printing ink.

6. The preparation method according to claim 5, characterized in that, In step (1), after the edible mushroom residues are crushed, their particle size is less than 100 mesh.

7. The preparation method according to claim 5, characterized in that, In step (2), when dissolving the hydrocolloid powder in water, high-speed stirring is adopted, the stirring speed is 1000-3000 revolutions per minute, and the stirring time is 10-30 minutes.

8. The preparation method according to claim 5, characterized in that, In step (3), when dissolving the hydrocolloid powder, first heat the water to 40-60 °C, and then add the hydrocolloid powder.

9. The preparation method according to claim 5, characterized in that, In step (4), during the water bath heating process, stir once every 5-10 minutes, and the stirring speed is 100-300 revolutions per minute.

10. The preparation method according to claim 5, characterized in that, After the water bath heating in step (4) is completed, place the material in an environment at 3 °C and quickly cool it to 12 °C, and then slowly warm it up to room temperature.

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