Method for improving juice loss after freeze thawing of 3D printing recombined fruit and vegetable food by utilizing internal filling honeycomb structure

Abstract

The invention provides a method for improving juice loss after freezing and thawing of 3D printing recombined fruit and vegetable food by utilizing an internal filling honeycomb structure, relates to a food processing technology, and belongs to the field of novel food processing 3D printing. According to the method, firstly, fresh fruits and vegetables are cooked and beaten into homogenate, then a small amount of fruit and vegetable powder and food colloid are added, filling is conducted after even mixing, and then a specific 3D printing model and corresponding 3D printing parameters are designed. Compared with other filling structures such as grids and crossed corrugations, the method has the advantages that the internal filling mode of the honeycomb structure is selected to be different in filling rate during printing, so that juice loss after freezing and thawing after sample printing can be remarkably reduced under the same filling rate, other equipment for post-treatment is not needed, and industrial equipment cost and energy consumption are saved. The procedure allows food with attraction to be created for eating in restaurants or homes, meanwhile, juice loss after freezing and thawing can be reduced, and the quality of frozen 3D printing fruit and vegetable food is improved.

Description

Technical Field

[0001] The invention relates to a method for improving juice loss of 3D printed reconstituted fruit and vegetable food after freezing and thawing by utilizing an internally filled honeycomb structure, relates to food processing technology, and belongs to the field of 3D printing in food processing technology. Background Art

[0002] 3D printing, also known as additive manufacturing (AM), creates three-dimensional models designed by computer-aided design (CAD) and computer software such as Rhino. The technology combines design and production and is suitable for a wide range of printing materials, including polymer ceramics, powder-based inks, cell culture or bio-based inks, clay, concrete, metals and food. 3D food printing technology has recently become popular due to its main advantages such as nutritional personalization, complex shapes and textures, high efficiency, reduced food waste, rapid prototyping and customized food. In the food industry, extrusion printing, inkjet printing, binder jetting and selective sintering are the main 3D printing technologies, among which extrusion printing is the easiest to develop and the most widely used. The technology accumulates the designed model by extruding the material layer by layer through the nozzle of a syringe embedded in a robotic arm that moves along the surface.

[0003] Fruits and vegetables, with their high biological variability affected by environmental factors and low viscosity due to their high water content, may be considered the most difficult materials to print. At the same time, they are highly perishable due to their high water content. Recent studies have shown that 3D printed fresh vegetables containing as little food colloid as possible, rather than dehydrated and freeze-dried vegetable powders, may be suitable for elderly people with dysphagia. Freezing is one of the most commonly used methods to maintain the quality and safety of fresh cell foods during packaging, cooling, drying, etc. The formation of ice crystals during freezing is a key step that affects freezing efficiency and the quality of frozen products. Other factors that affect the quality of frozen products are the physical properties of plant tissues, such as the porosity of intercellular spaces and the porosity of tissues, which is generally related to cell size. Thawing is the reverse process of freezing and has a great influence on the quality and physicochemical properties of frozen products. After thawing, juice loss and texture loss (hardness loss) will reduce the quality of thawed products.

[0004] Honeycomb is a magical product of nature and the most representative example of porous structure in nature. Honeycomb honeycomb structure is derived from natural honeycomb in the nest and consists of double-layer hexagonal honeycombs evenly distributed. The materials for building the cell wall are beeswax and propolis (a plant resin). Because it is very similar to the honeycomb of bees, scientists have found that the hexagonal structure performs well, has the largest available space, and shows great mechanical potential. Research on the characteristics of honeycomb structure has been carried out for thousands of years. However, honeycomb structure was not incorporated into large-scale applications in human society until about 70 years ago. Since then, many honeycomb structures made of various materials have appeared, and the technology used to manufacture honeycomb structures has gradually improved. In particular, in the past two decades, we have witnessed the further expansion of honeycomb structure from the engineering field to the nano and biomedical fields, such as nanopore arrays in anodized aluminum, micropore arrays in polymer films, activated carbon honeycombs, and photonic bandgap honeycomb structures. In particular, in 1999, Hales finally proved the conjecture that the way bees build honeycombs is to provide the largest cell space by using the least amount of beeswax, indicating that the hexagonal honeycomb structure is the most stable for nature. Recently, Karihalo and his colleagues revealed the mechanism of the rapid transformation of round honeycomb cells into round hexagonal structures in natural honeycombs, namely the formation of molten viscoelastic wax heated by "hot" worker bees flowing around the triple junctions of adjacent round cells. This discovery witnesses a powerful continuation of the long-standing debate over whether honeycombs are an example of blind physics or delicate bioengineering.

[0005] Zhang Min et al. (2019) invented a single nozzle 3D printing method for heterogeneous reconstituted food containing rose petals (CN109700063A). The invention first washed the white kidney beans and soaked them in cold water for 12 hours before peeling them, then steamed them for 40 minutes to soften the white kidney beans, then mixed the pulped slurry with white sugar and simmered it over low heat until the bean paste became viscous, and after the bean paste cooled to room temperature, butter, fine sugar, and whipped cream were added to beat the bean paste, and finally rose petals with different addition amounts and sizes treated with surface oiliness were added. The main material used for printing in the present invention is white bean paste, which can be used as desserts and snacks for catering cold dishes. The invention uses a single nozzle to realize a method for 3D printing of heterogeneous reconstituted food containing rose petals. Rose petals are rich in various nutrients, and this method turns rose petals, which were originally scraps, into treasure. The invention does not have a complicated and long-term processing process, saves production costs, and has strong operability.

[0006] Zhang Min et al. (2020) invented a method for developing 3D printed food containing probiotics using rose pollen and high-sugar fruit crumbs (CN 111802636A). The invention crushed and sieved freeze-dried rose petals / crumbs and high-sugar fruit crumbs at low temperature, mixed them with milk, and introduced 0.5% to 1.5% food colloids, and 3D printed them under sterile conditions. By controlling the nozzle diameter and printing temperature, combined with oligosaccharides in high-sugar fruits, the number of probiotics in the 3D printed food was finally achieved to be 9 to 10 log cfu / g, and the number of probiotics was 8 to 9 log cfu / g after storage at 4°C for 7 days. The survival rate of probiotics exceeded 85%.

[0007] Zhang Min et al. (2018) invented a method for 3D precise printing of easy-to-swallow dual-color mashed potato / purple mashed sweet potato cold dish (CN108477545A). The steps of the invention are as follows: (1) Wash and peel fresh potatoes and purple sweet potatoes, slice them, steam and beat them; (2) Add a compound system of xanthan gum and pectin to mashed potatoes and purple sweet potatoes respectively; (3) Keep the mashed potatoes and purple sweet potatoes warm after adding the colloid; (4) After cooling to room temperature, add appropriate amount of salt, seasoning and olive oil to the mashed potatoes; add honey and olive oil to the purple sweet potato; (5) Select the nozzle diameter; (6) Determine the printing speed; (7) Determine the relative position of the dual nozzles; (8) Determine the filling ratio and filling mode during printing; (9) With the help of a dual-nozzle printer, use a dual-color 3D printing model to print the mashed potatoes / purple sweet potatoes. The method of the present application can better ensure the normal nutrition supply and dietary swallowing safety of the elderly.

[0008] Zhang Min et al. (2020) invented a microwave-coordinated 3D printing device and a precise and efficient printing method for plant gel systems (CN 110742294A). The device of the invention includes a 3D printer, a built-in real-time microwave heating and curing device, a flexible microwave shielding box, an embedded online microwave real-time controller, etc. The microwave source is a solid-state microwave source, and the power is continuously adjustable in the range of 20 to 200W. The microwave energy feeding is realized by a rotating antenna to ensure that the microwave is uniformly absorbed by the material layer during the printing process. The device can realize real-time heating and curing of microwaves during the 3D printing process, achieve rapid curing to improve printing accuracy, and shorten the efficiency of 3D printing food production under the whole process. According to the material properties, such as rheological properties and dielectric properties, a matching relationship is established between the printing extrusion speed of the material during 3D printing and the microwave real-time heating power, so as to achieve the appropriate curing of the material, thereby achieving a printing accuracy of more than 95%, and no deformation occurs in the subsequent process.

[0009] Zhang Min et al. (2018) invented a method for improving 3D printing effects by pre-treatment of concentrated fruit pulp (CN108294257A). The invention adds the prepared concentrated fruit pulp gel into the hopper of the 3D printer, selects the 3D printing parameters corresponding to the 3D printing model and system for 3D printing, performs appropriate trimming on the printed product according to the shape of the target model, and finally coats and quickly freezes the surface of the printed product. The present invention improves the 3D precision printing performance by changing the size of the print nozzle and using high-speed homogenization to refine the material texture during the preparation process. It is directly used as a healthy and nutritious raw material for product formulas and process steps, does not add any artificial synthetic pigment components, and is safe and reliable; the present invention does not have a complicated and long-term processing process, saves costs, has strong operability, and fully provides the entire process of processing and storage and transportation and recommended matters.

[0010] Zhang Min et al. (2017) invented a formula control method for improving the molding and 3D precision printing performance of high-sugar systems (CN 107334140A). The invention adopts three key aspects of control to achieve the purpose of improving the molding and 3D printing performance of high-sugar systems. The first is to soak and ensure that the gelatin is completely dissolved to obtain a uniform and dense high-sugar gel system. The second is to stir to ensure that the gelatin can be completely dissolved in the end, the system is stabilized, and the particles are fine. The third is to use steaming to sterilize and finally obtain a finished product that can be eaten directly. At the same time, this can also promote the fusion of various ingredients and finally obtain a uniform and stable system. Add an appropriate amount of weak preservative citric acid and dry nano fruit and vegetable powder as needed; adding nano fruit and vegetable powder can significantly reduce the ductility of the material, thereby reducing the possibility of deformation or collapse after printing. The invention studies the size of the printing nozzle and adopts high-speed homogenization to refine the material texture to improve the 3D precision printing performance. There is no complicated and long-term processing process, which saves costs and has strong operability.

[0011] Zhang Min et al. (2020) invented a method for 4D printing artistic cold dishes by using microwave-induced spontaneous deformation (CN111543664A). The invention first mixes fructose syrup, water, potato flour, potato starch, and food colloids, and then homogenizes, cooks, cools, and loads them. Then, the 3D printing model and the corresponding 3D printing parameters are selected for 3D printing on food-grade PA / PE pad paper. The pad paper is appropriately cut according to the shape of the printed sample to obtain a double-layer structure of mashed potato / paper. The printed sample is subjected to microwave induction, and the sample will spontaneously bend and deform perpendicular to the printing path. Changes in the fourth dimension are achieved on the basis of 3D printing. By designing different models and setting different printing parameters, the present invention can print materials into different two-dimensional shapes, and transform them into three-dimensional spatial structures through microwave induction, so that the food has a richer visual effect and realizes the diversified, personalized, and automated production of products.

[0012] Zhang Min et al. (2020) invented a method for 4D printing of colored jelly using the spontaneous color change of blueberry anthocyanins. The invention fully mixed two raw materials, blended, homogenized, gelled, cooled, loaded, and degassed them respectively, and then used a dual-nozzle printer to perform 3D printing of multi-material color-carrying layers and color-controlling layers layer by layer according to the established 3D printing model. The color of the printed color-carrying layer jelly will change from purple-red to red, purple, and blue within 2 minutes according to the pH value of the color-changing layer in contact. The change of the fourth dimension is realized on the basis of 3D printing. The food printed by this method has a richer visual effect, which can realize the personalized and diversified production of products.

[0013] The above inventions realize 3D printing of various food systems such as polysaccharides, starch-based and their reconstructed systems, and solve the problem of poor printing accuracy of food gel systems. In addition, post-processing is performed on the basis of 3D printing to realize 4D printing with deformation and discoloration. However, the above inventions mainly focus on 3D printing itself, while the present invention focuses on food preservation after 3D printing, providing a simple and effective method for improving the quality of frozen reconstructed fruits and vegetables (in terms of juice loss after freeze-thaw). Summary of the invention

[0014] The purpose of the present invention is to develop a method for improving the loss of juice after freeze-thaw of reconstituted fruits and vegetables by using an internal filling honeycomb structure after food 3D printing, so as to improve the freezing quality of 3D printed reconstituted fruits and vegetables.

[0015] The technical solution of the present invention:

[0016] A method for improving the loss of juice after freezing and thawing of 3D printed reconstituted fruit and vegetable food by using an internally filled honeycomb structure, the specific steps are as follows:

[0017] (1) Preparation of reconstituted fruit and vegetable slurry: Wash the fruits and vegetables thoroughly and steam until the texture is soft; drain the steamed fruits and vegetables or fresh fruits and vegetables and put them into a food blender for blending; mix the fruit and vegetable slurry, fresh fruits and vegetables and carrot powder in a mass ratio of 88:10-68:30, add 2% xanthan gum to the total mass of the fruit and vegetable slurry and carrot powder, and then homogenize with a homogenizer;

[0018] (2) 3D printing: Select the 3D printing model, set the filling mode to honeycomb structure, set the 3D printing parameters and print on the printing pad. The printing model is a rectangular parallelepiped, the nozzle diameter is 0.8 mm, the layer height is 0.8 mm, the printing speed is 22 mm / s, the filling angle is 0°, the filling ratio is 20%-100%, the number of shell circles is 2, and the printing pad is food-grade PA / PE plastic paper, which is freeze-resistant and heat-resistant. The printed reconstituted fruits and vegetables are easy to fall off the paper after freezing. After printing, they are packaged and stored.

[0019] Preferably, in step (1), the moisture content of the fruit and vegetable slurry is similar to the moisture content of fresh fruits and vegetables.

[0020] Preferably, in step (1), the stirring time is 5-10 min and the homogenization time is 2-5 min.

[0021] Preferably, in step (2), the size of the cuboid is 30×30×8 mm.

[0022] Preferably, in step (2), the thickness of the food-grade PA / PE plastic paper is 0.2 mm.

[0023] Preferably, in step (2), the porosity calculation method of the 3D printed sample at different filling rates is: Porosity (%) = (V de -V ac ) / V de - × 100%, where V de is the volume of the designed model, V ac is the actual volume of the printed sample; the density of the reconstituted fruit and vegetable slurry was measured using the volume exclusion method; the initial volume of ethanol in the measuring cylinder was recorded as V 1 , the volume after the reconstituted fruit and vegetable slurry wrapped in plastic wrap is put in is recorded as V 2 The weight of the reconstituted fruit and vegetable slurry is pre-measured as M, so its density (g / cm 3 )=M / (V 2 -V 1 ).

[0024] Preferably, the filling ratios are 20%, 40%, 60%, 80% and 100%, respectively, and the corresponding printing porosities are 54.97%, 38.25%, 21.82%, 1.06% and 0%, respectively.

[0025] An experimental method for measuring the juice loss rate of 3D printed fruit and vegetable food after freezing and thawing, comprising the following steps:

[0026] (A) Freezing: Place the printed product in a -80°C freezer for 6-12 hours;

[0027] (B) Thawing: Weigh the printed sample frozen in step (A) w f And put it in the pre-weighed 0 The samples were then thawed in a glass culture dish and packed in a polyethylene bag using the static air method. The entire thawing process was carried out at room temperature of 25±1℃ for 3-6h.

[0028] (C) Determination of juice loss after freeze-thaw: After thawing, weigh the filter paper wt to calculate the juice loss. The mathematical expression is as follows:

[0029]

[0030] Beneficial effects of the present invention: The present invention improves the loss of juice after freeze-thaw of 3D printed reconstituted fruits and vegetables for the first time by filling the honeycomb structure internally. Compared with other filling modes, at the same filling rate, i.e., porosity, the loss of juice after freeze-thaw of reconstituted fruits and vegetables can be effectively improved, and the quality of high-moisture frozen 3D printed food can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A top view of an internally filled honeycomb structure model with a filling rate of 60% in the embodiment.

[0032] Figure 2 A top view of the internal filling grid structure model with a filling rate of 60% in Example 1.

[0033] Figure 3 A top view of the internally filled cross-corrugated structure model with a filling rate of 60% in Example 2.

[0034] Figure 4 A top view of the internally filled triangular structure model with a filling rate of 60% in Example 3. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below by examples. These examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0036] Example 1: Comparison of juice loss after freezing and thawing of green vegetable gel system with internal filling honeycomb structure and grid structure

[0037] First, wash the bok choy thoroughly and steam for 15 minutes until the texture is soft. Drain the steamed bok choy and blend in a food blender for 5 minutes. Thoroughly mix the bok choy pulp and carrot powder in a mass ratio of 84:14, add 2% xanthan gum to the total mass and homogenize with a homogenizer for 2 minutes;

[0038] After filling the reconstituted fruit and vegetable pulp into the syringe, load it into the printer material barrel, select the 3D printing model (30×30×8mm cuboid), import its .stl file into the Simplify3D software, and set two printing processes. The filling mode of process 1 is honeycomb structure, the filling angle is 0°, and the filling mode of process 2 is grid, the filling angle is 45° and -45°, and other parameters are consistent, such as nozzle diameter of 0.8mm, printing speed of 22mm / s, shell number of circles 2, filling rate of 20%, 40%, 60%, 80% and 100%, which correspond to the printing porosity of 54.97%, 38.25%, 21.82%, 1.06% and 0% respectively; after the printing process parameters are set, start slicing, and then fix the printing pad of the model on the printing platform for printing.

[0039] After printing, the sample was placed in a -80 °C freezer for 8 h, and then the frozen printed sample was weighed (w f ) and placed in a pre-weighed (w 0 ) on filter paper, then thawed in a glass Petri dish and packaged in a polyethylene bag (static air method). The entire thawing process was carried out at room temperature (25±1℃) for 4h, and the juice loss is shown in Table 1. With the decrease of porosity, the juice loss was significantly reduced (p<0.05), and at the same porosity, the internal filling honeycomb structure had less juice loss than the grid structure.

[0040] Table 1 Effects of honeycomb structure and grid structure on juice loss after freezing and thawing

[0041]

[0042] Example 2: Comparison of juice loss after freezing and thawing of yellow peach gel system with internal filling honeycomb structure and cross-corrugated structure

[0043] First, wash the peaches thoroughly and steam them for 15 minutes until the texture is soft. Drain the steamed peaches, peel them, and blend them in a food blender for 5 minutes. Mix the peach pulp, carrot powder, and xanthan gum in a mass ratio of 88:10, add 2% xanthan gum to the total mass, and blend them in a homogenizer for 2 minutes.

[0044] After filling the reconstituted fruit and vegetable pulp into the syringe, load it into the printer material barrel, select the 3D printing model (30×30×8mm cuboid), import its .stl file into the Simplify3D software, and set two printing processes. The filling mode of process 1 is a honeycomb structure with a filling angle of 0°, and the filling mode of process 2 is a cross-corrugated structure with filling angles of 0° and 90°. Other parameters are kept consistent, such as a nozzle diameter of 0.8mm, a printing speed of 22mm / s, a filling rate of 20%, 40%, 60%, 80% and 100%, and a shell number of 2, which correspond to printing porosities of 54.97%, 38.25%, 21.82%, 1.06% and 0% respectively; after the printing process parameters are set, start slicing, then fix the printing pad of the model on the printing platform and perform the printing operation.

[0045] After printing, the sample was placed in a -80 °C freezer for 8 h, and then the frozen printed sample was weighed (w f ) and placed in a pre-weighed (w 0) on filter paper, then thawed in a glass Petri dish and packaged in a polyethylene bag (static air method). The entire thawing process was carried out at room temperature (25±1℃) for 4h, and the juice loss is shown in Table 2. With the decrease of porosity, the juice loss was significantly reduced (p<0.05), and at the same porosity, the juice loss of the internal filling honeycomb structure was less than that of the cross-corrugated structure.

[0046] Table 2 Effects of honeycomb structure and cross-corrugated structure on juice loss after freezing and thawing

[0047]

[0048] Example 3: Comparison of juice loss after freeze-thaw of carrot gel system with internal honeycomb structure and triangular structure

[0049] First, wash the carrots thoroughly and steam them for 15 minutes until the texture is soft. Drain the steamed carrots and blend them in a food blender for 5 minutes. Mix the carrot pulp and carrot powder in a mass ratio of 80:18, add 2% xanthan gum to the total mass and homogenize with a homogenizer for 2 minutes;

[0050] After filling the recombinant fruit and vegetable pulp into the syringe, load it into the printer material barrel, select the 3D printing model (30×30×8mm cuboid), import its .stl file into the Simplify3D software, and set two printing processes. The filling mode of process 1 is a honeycomb structure with a filling angle of 0°, and the filling mode of process 2 is a triangular structure with filling angles of 0°, 60° and -60°. Other parameters are kept consistent, such as a nozzle diameter of 0.8mm, a printing speed of 22mm / s, a filling rate of 20%, 40%, 60%, 80% and 100%, and a shell number of 2, which correspond to printing porosities of 54.97%, 38.25%, 21.82%, 1.06% and 0% respectively; after the printing process parameters are set, start slicing, then fix the printing pad of the model on the printing platform and perform the printing operation.

[0051] After printing, the sample was placed in a -80 °C freezer for 8 h, and then the frozen printed sample was weighed (w f ) and placed in a pre-weighed (w 0 ) on filter paper, then thawed in a glass Petri dish and packed in a polyethylene bag (static air method). The entire thawing process was carried out at room temperature (25±1℃) for 4h, and the juice loss is shown in Table 3. With the decrease of porosity, the juice loss was significantly reduced (p<0.05), and at the same porosity, the internal filling honeycomb structure had less juice loss than the triangular structure.

[0052] Table 3 Effects of honeycomb structure and triangular structure on juice loss after freezing and thawing

[0053]

Claims

1. A method for improving the loss of juice after freezing and thawing of 3D printed reconstituted fruit and vegetable food by using an internally filled honeycomb structure. It is characterized in that The specific steps are as follows: (1) Preparation of reconstituted fruit and vegetable slurry: Wash the fruits and vegetables thoroughly and steam until the texture is soft; drain the steamed fruits and vegetables or fresh fruits and vegetables and put them into a food blender for blending; mix the fruit and vegetable slurry, fresh fruits and vegetables and carrot powder in a mass ratio of 88:10-68:30, add 2% xanthan gum to the total mass of the fruit and vegetable slurry and carrot powder, and then homogenize with a homogenizer; (2) 3D printing: Select the 3D printing model, set the filling mode to honeycomb structure, set the 3D printing parameters and print on the printing pad. The printing model is a rectangular parallelepiped, the nozzle diameter is 0.8 mm, the layer height is 0.8 mm, the printing speed is 22 mm / s, the filling angle is 0°, the filling ratio is 20%-100%, the number of shell circles is 2, and the printing pad is food-grade PA / PE plastic paper, which is freeze-resistant and heat-resistant. The printed reconstituted fruits and vegetables are easy to fall off the paper after freezing. After printing, they are packaged and stored.

2. According to claim 1, a method for improving the loss of juice after freezing and thawing of 3D printed reconstituted fruit and vegetable food by using an internally filled honeycomb structure, It is characterized in that In step (1), the moisture content of the fruit and vegetable slurry is similar to the moisture content of fresh fruits and vegetables.

3. According to claim 1, a method for improving the loss of juice after freezing and thawing of 3D printed reconstituted fruit and vegetable food by using an internally filled honeycomb structure, It is characterized in that In step (1), the stirring time is 5-10 min and the homogenization time is 2-5 min.

4. According to claim 1, a method for improving the loss of juice after freezing and thawing of 3D printed reconstituted fruit and vegetable food by using an internally filled honeycomb structure, It is characterized in that In step (2), the size of the cuboid is 30×30×8 mm.

5. According to claim 1, a method for improving the loss of juice after freezing and thawing of 3D printed reconstituted fruit and vegetable food by using an internally filled honeycomb structure, It is characterized in that In step (2), the thickness of the food-grade PA / PE plastic paper is 0.2 mm.

6. The method of improving the juice loss of 3D printed reconstituted fruit and vegetable food after freezing and thawing by using an internally filled honeycomb structure according to claim 1, It is characterized in that In step (2), the porosity calculation method of the 3D printed sample at different filling rates is: Porosity (%) = (V de -V ac ) / V de - × 100%, where V de is the volume of the designed model, V ac is the actual volume of the printed sample; the density of the reconstituted fruit and vegetable slurry was measured using the volume exclusion method; the initial volume of ethanol in the measuring cylinder was recorded as V 1 , the volume after the reconstituted fruit and vegetable slurry wrapped in plastic wrap is put in is recorded as V 2 The weight of the reconstituted fruit and vegetable slurry is pre-measured as M, so its density (g / cm 3 )=M / (V 2 -V 1 ).

7. The method of improving the juice loss of 3D printed reconstituted fruit and vegetable food after freezing and thawing by using an internally filled honeycomb structure according to claim 1, It is characterized in that The filling ratios are 20%, 40%, 60%, 80% and 100%, respectively, and the corresponding printing porosities are 54.97%, 38.25%, 21.82%, 1.06% and 0%, respectively.

8. An experimental method for measuring the juice loss rate of 3D printed fruit and vegetable foods after freezing and thawing. It is characterized in that The following steps are involved: (A) Freezing: Place the printed product in a -80°C freezer for 6-12 hours; (B) Thawing: Weigh the printed sample frozen in step (A) w f And put it in the pre-weighed 0 The samples were then thawed in a glass culture dish and packed in a polyethylene bag using the static air method. The entire thawing process was carried out at room temperature of 25±1℃ for 3-6h. (C) Determination of juice loss after freeze-thaw: After thawing, weigh the filter paper wt to calculate the juice loss. The mathematical expression is as follows:

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