3D printing method of citrus nucellar heterogeneous distribution tea

Abstract

The application discloses a 3D printing method of a citrus sac non-homogeneous distribution tea snack, and comprises the following steps: first, preparing a protein polysaccharide gel with thermal reversibility to facilitate the mixing and uniform dispersion of non-homogeneous materials; based on the thermal reversibility of polysaccharide, a recyclable protein polysaccharide 3D edible ink is developed; second, through high-speed homogenization or ultrasonic vacuum-assisted immersion of ascorbic acid and tea polyphenol, the citrus sac is subjected to osmotic dehydration treatment, and the size of the citrus sac particles is reduced, and the 3D printing characteristics are improved. Through ultrasonic vacuum-assisted immersion of ascorbic acid and tea polyphenol, the citrus sac not only increases the taste of a mouthful of juice of the tea snack with non-homogeneous distribution of citrus sacs, but also improves the nutritional characteristics of the non-homogeneous printing product containing citrus sacs. In the application, different treatment methods are selected for different size types of citrus sac particles, and the non-homogeneous 3D printing is carried out by matching appropriate printing parameters, so that the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the non-homogeneous distribution of the

Description

Technical Field

[0001] This invention relates to a 3D printing method for tea snacks with heterogeneous distribution of citrus sac cells, which belongs to the field of novel food processing technology. Background Technology

[0002] 3D food printing technology is gaining increasing recognition in the global food processing industry. By integrating nutrient-rich materials such as probiotics, bioactive compounds, and functional ingredients into complex reconstituted foods, it enables on-demand food production, automated food processing, and personalized design. It also promotes food supply chain simplification and sustainable development by minimizing food waste. The range of printable food material systems extends from natural printable materials (hydrogels, cake frosting, cheese, and chocolate) to non-traditional food materials (meat, fruit, rice, and vegetables) and alternative ingredients (algae, fungi, insects, lupins, etc.). These printable food materials are generally present or ground into a homogeneous system with similar particle sizes. Through pretreatment, they can be transformed into a paste at room temperature or melting temperature, exhibiting shear thinning and self-supporting properties. They are easily extruded from the nozzle and possess sufficient strength to support the shape of the deposited product.

[0003] Citrus sacs, obtained from citrus fruits through a desiccation process, are rich in vitamins, organic acids, minerals, and other bioactive substances beneficial to the human body. Therefore, adding sweet and sour citrus sacs to dairy products for heterogeneous printing can not only produce 3D-printed sour products with richer flavor profiles but also expand the range of printing materials for foods for the elderly and children. However, adding heterogeneous food materials (of uneven size) requires consideration of the compatibility between the material size and the printing nozzle diameter. Because canned citrus sac particles are plump, juicy, and difficult to bend, and their size is uneven, even if smaller particles are vertically arranged in the printing tube and can pass through the largest printing nozzle (3.0 mm), it cannot be guaranteed that all particles will be arranged in the desired manner. This is a major challenge of heterogeneous systems and urgently needs a solution. Furthermore, to meet the increasing protein intake needs of the elderly, 3D-printed protein-based foods are gradually gaining popularity. Compared to plant proteins, animal proteins contain amino acids in proportions that meet human needs. However, animal proteins often have poor gel properties, especially whey protein isolate, whose gels are brittle and prone to shrinkage. Such pure protein systems are not suitable for 3D printing and cannot meet the controllability requirements for mixing and distributing heterogeneous food materials with homogeneous protein systems in heterogeneous printing.

[0004] Zhang et al. (2019) disclosed a single-nozzle 3D printing method for heterogeneous recombinant food containing rose petals (CN109700063A). This invention uses white kidney beans as the main material, soaking them for 12 hours, peeling them, steaming them for 40 minutes, and then pulping them. The resulting pulp is mixed with granulated sugar and simmered over low heat until the bean paste thickens. The cooled bean paste is then whipped with butter, granulated sugar, and light cream. Finally, rose petals of different amounts and sizes, with a surface oiling treatment, are added. This invention is the first to study the 3D printing of heterogeneous recombinant food components, turning waste rose petals into a valuable resource. However, the heterogeneous material added is dried rose petals with low water content and requires surface oiling treatment. This invention differs in that the heterogeneous additive is citrus sac cells with high water content, and the homogeneous system is a thermally reversible protein gel.

[0005] Hu Qiuhui et al. (2022) invented a 3D printing ink for king oyster mushrooms, its preparation method and application, and a method for preparing 3D printed food products from king oyster mushrooms (CN115336742A). This invention uses freeze-dried king oyster mushroom powder with low moisture content as material, and adds one or more hydrophilic colloids from sodium alginate, gellan gum, pectin, methylcellulose, locust bean gum and guar gum to improve the printing feasibility of the freeze-dried king oyster mushroom powder. This invention solves the problem of king oyster mushrooms with high fiber content clogging the 3D printing nozzle, and retains the bioactive substances in king oyster mushrooms to the maximum extent. However, the main research of this experiment is to make the freeze-dried king oyster mushroom powder into a homogeneous system with a particle size ≤0.15 mm. In contrast, the heterogeneous material citrus cysts added in this invention, after being impregnated with ultrasonic vacuum-assisted tea polyphenols and ascorbic acid, also maximizes the nutritional characteristics of the material, and the diameter after different treatments is between 0.5-3.0 mm, which is a heterogeneous 3D printing material.

[0006] Zhou Quancheng et al. (2018) disclosed a method for preparing 3D printing materials based on persimmon pulp and its application (CN108813708A). This invention uses persimmon pulp as raw material, adding a mixture of protein, butter, vegetable juice, and water to produce 3D printed materials based on persimmon pulp. The raw materials are simple and readily available, the preparation method is simple, and the printed product has good shape, bright color, and high stability. It also retains the nutrients of persimmon pulp and improves its astringent and overly sweet taste. This invention mainly involves printing a uniformly mixed protein-based material containing persimmon pulp, which is significantly different from the 3D printing method of this invention using a protein-based heterogeneous recombinant material with added citrus sac cells.

[0007] Zhou Peng et al. (2018) disclosed a method for precise 3D printing of high-protein semi-fluid ready-to-eat foods (CN109090616A). This invention uses high-quality concentrated milk protein as the main raw material and adds appropriate amounts of polysaccharide colloids to establish a method for precise 3D printing of high-protein semi-fluid ready-to-eat foods. This method enables the 3D printing of high-protein foods, which can be accepted by a wide range of consumers as low-calorie, high-nutrient health foods. The semi-solid foods obtained after 3D printing are soft, easy to chew and swallow, and suitable for children and the elderly. The proteoglycan system prepared by this method is in a semi-solid state, which is different from the thermally reversible proteoglycan gel prepared in this invention. This allows for controllability in the mixing and distribution of heterogeneous food materials with homogeneous systems in heterogeneous printing.

[0008] Wang Xiaolong et al. (2021) disclosed a method for preparing 3D-printed thermally reversible hydrogels (CN112979996A). This invention provides thermally reversible hydrogel ink; it uses thermal field-assisted ink direct writing 3D printing technology to 3D print the thermally reversible hydrogel ink to obtain a three-dimensional thermally reversible hydrogel structure; the three-dimensional thermally reversible hydrogel structure is gelled to obtain a 3D-printed thermally reversible hydrogel; the solute of the thermally reversible hydrogel ink is a thermally reversible natural macromolecule, or a thermally reversible natural macromolecule and a synergistically compounded gel. This invention focuses on overcoming the key problem that traditional thermally reversible natural macromolecules are difficult to directly apply in the 3D printing process, which is different from the focus of this experiment. This experiment adds fruit particles while achieving thermal printing, providing the application of thermally reversible hydrogels in heterogeneous 3D printing, and also adding a wonderful burst of juice to the product. Summary of the Invention

[0009] Technical Problem Solved: This invention provides a 3D printing method for tea snacks containing heterogeneously distributed citrus sac cells. The method first prepares a thermally reversible proteoglycan gel to facilitate the mixing and uniform dispersion of heterogeneous materials. Based on the thermal reversibility of polysaccharides, a recyclable proteoglycan-based edible 3D ink is developed. Secondly, citrus sac cells are permeated and dehydrated through high-speed homogenization or ultrasonic vacuum-assisted impregnation with ascorbic acid and tea polyphenols. Both methods reduce the size of the citrus sac cell particles and improve their 3D printing properties. Ultrasonic vacuum-assisted impregnation of citrus sac cells with ascorbic acid and tea polyphenols not only adds a juicy texture to the tea snacks with heterogeneously distributed citrus sac cells but also improves the nutritional properties of the printed products containing heterogeneously distributed citrus sac cells. This invention obtains nutritious ready-to-eat tea snacks with different textures and flavors by selecting different treatment methods for citrus sac cell particles of different sizes and matching appropriate printing parameters for heterogeneous 3D printing. The raw materials of this invention are simple and readily available, the preparation method is simple and highly operable, and it can be used as a dessert for cold dishes in high-end tea restaurants, coffee shops, dessert shops and home kitchens.

[0010] Technical solution: A 3D printing method for heterogeneous distribution of citrus sac cells, comprising the following steps: (1) Preparation of thermally reversible proteoglycan gel: Dissolve protein powder in water, stir and hydrate overnight to form a uniformly dispersed protein solution with a protein concentration of 10-20 g / 100mL; add hydrophilic colloid and stir to completely dissolve it in the protein solution with a total amount of hydrophilic colloid added of 0.5-2 g / 100mL; heat the proteoglycan solution to denature it to form a thermosol, and cool it to form a proteoglycan gel at 4°C. Refrigerate in a refrigerator at ℃ for later use; (2) Pretreatment of citrus sac granules: Add xylitol solution to citrus sac granules and prepare citrus pulp homogenate using a high-speed shear homogenizer; or, immerse citrus sac granules in xylitol solution for osmotic dehydration to maintain the integrity of the granules, and use ultrasonic vacuum equipment to assist the osmotic dehydration process; or, immerse citrus sac granules in xylitol solution with added tea polyphenols or ascorbic acid for osmotic dehydration to maintain the integrity of the granules while enriching their dietary nutrients. The amount of tea polyphenols and ascorbic acid added is 0.5-1 g / 100mL, and ultrasonic vacuum equipment is used to assist the osmotic dehydration process; The xylitol concentration of the above xylitol solution osmotic treatment is 30-50 °Brix, the mass ratio of liquid to material is 1:(2-5); (3) Add citrus cyst particles: Melt the proteoglycan gel prepared in step (1) in a rotating water bath, add the citrus pulp homogenate or dehydrated citrus cyst particles prepared in step (2), stir and mix them evenly with the proteoglycan to obtain proteoglycan mixed ink containing citrus cysts; the amount of citrus pulp homogenate or dehydrated citrus cyst particles added is 1 wt.%-10 wt.% of the proteoglycan gel obtained in step (1); (4) 3D printing: Fill the printing tube with the proteoglycan mixed ink containing citrus cysts obtained in step (3) in sol state, set the printing parameters and print.

[0011] Preferably, the protein powder in step (1) above is any one of whey protein isolate, peanut protein isolate, mung bean protein, walnut protein, and soy protein isolate; the hydrophilic colloid includes at least one of carrageenan, gellan gum, guar gum, pectin, sodium alginate, konjac gum, locust bean gum, gum arabic, and flaxseed gum; the thermal denaturation temperature of the proteoglycan solution is 70-90 ℃, and the heating duration is 10-30 min.

[0012] Preferably, in step (2) above, the size of the citrus cyst particles after being crushed by a high-speed shear homogenizer is between 0.5 and 1.5 cm, and the prepared crushed citrus cyst particles are placed in a refrigerator at 4 ℃ for later use.

[0013] Preferably, in step (2) above, the power of ultrasonic treatment is 150-450 W and the treatment time is 10-30 min.

[0014] Preferably, in step (2) above, the vacuum degree of vacuum treatment is 0.01-0.05 MPa, the treatment time is 10-30 min; ultrasonic vacuum starts and ends at the same time, the treatment time is 10-30 min, and then the infiltration continues for 60-180 min at room temperature and atmospheric pressure.

[0015] Preferably, in step (3) above, the temperature of the proteoglycan gel in the rotating water bath is maintained at 35-45 ℃ and the holding time is 15-30 min, so that the solid proteoglycan gel becomes a liquid sol state.

[0016] Preferably, the 3D printing parameters in step (4) above include: printing temperature of 35-37 ℃, nozzle diameter of 2.0-3.0 mm, nozzle moving speed of 10-15 mm / s, and material output speed of 22-25 mm. 3 / s, with a fill rate of 70%-90%.

[0017] The technical solution of this invention mainly adopts three key aspects of control to achieve the 3D printing of tea snacks with heterogeneous distribution of citrus cysts: First, selecting a suitable colloidal ratio to blend with whey protein isolate to form a thermally reversible gel can improve the mixing and dispersion effect; second, selecting appropriate ultrasonic or vacuum process parameters to impregnate citrus cysts with tea polyphenols and ascorbic acid; and third, optimizing to obtain the most suitable printing parameters such as nozzle diameter, printing temperature, printing speed, and filling method.

[0018] The hydrophilic colloids include carrageenan, gellan gum, and guarana, which possess thermally reversible properties. These hydrophilic colloidal molecules can form viscous solutions at high temperatures. When they cool below their critical temperature, hydrogen bonds form between the helical regions of different polysaccharide molecules, forming a solidified hydrogel. When they are reheated, these hydrogels melt, resulting in thermally reversible cryogelation. In contrast, when proteins are heated above their thermal denaturation temperature, the protein molecules unfold, exposing hydrophobic and sulfur-containing amino acid residues on their surface, forming a thermally irreversible thermosetting gel. This gel state is unsuitable for the preparation of 3D printing inks containing heterogeneous materials. By adding thermally reversible hydrophilic colloids, protein molecules interact with them through hydrophobic and disulfide bonds, leading to the formation of a semi-interpenetrating polymer network with the polysaccharide molecules. The gel properties of the protein are improved by combining with cryo-solid polysaccharides. Upon reheating, the hydrogel network structure formed by the polysaccharide molecules collapses, and the gel reverts to a sol state, facilitating the incorporation of materials for heterogeneous printing. Based on the thermal reversibility of polysaccharides, they are also used to develop recyclable 3D edible inks. The preferred order for various colloids is carrageenan > gellan gum > guaran gum, because lower cooling temperatures help ensure that the mixed heterogeneous materials maintain good quality properties.

[0019] The intermixing of these hydrophilic colloids can improve the problems of high brittleness and high water separation of individual hydrophilic colloids. The preferred order of various colloids is konjac gum > flaxseed gum > sodium alginate > locust bean gum > gum arabic > pectin, because the high water retention of konjac gum improves the water retention of printed products, thereby improving printing accuracy. Furthermore, the concentration of the intermixing hydrophilic colloids also improves the interaction strength and distribution between the colloid and protein, adjusts the texture of edible inks, and plays a decisive role in the printing effect.

[0020] To expand heterogeneous 3D printing materials, this invention uses citrus sac cells, rich in vitamins, organic acids, minerals, and other bioactive substances beneficial to the human body, as a heterogeneous additive. However, canned citrus sac cells are plump, juicy, difficult to bend, and their uneven size makes it difficult to ensure extrusion continuity during heterogeneous printing. The permeation dehydration operation is a two-way mass transfer process. Adding the required nutrients to the permeation solution can counteract the leaching effect of water-soluble components in the citrus sac cells during long-term permeation dehydration, thereby increasing the content of bioactive substances. The propagation of ultrasound in a liquid medium produces various effects (acoustic cavitation, sponge effect, acoustic flow or microfluidics and microchannels); the vacuum-induced decompression effect causes the air in the intercellular spaces and pores of the citrus sac cells to expand, and is expelled through a pressure-enhanced fluid dynamic mechanism, increasing the surface area available for mass transfer; the synergistic effect of these two factors promotes the permeation dehydration and nutrient enrichment process of citrus sac cells. This invention improves the printability of citrus sac cells while enhancing the nutritional characteristics of the citrus sac cells by screening different process parameters.

[0021] This invention also improves the appearance properties of heterogeneous 3D printed products by optimizing printing parameters. For larger citrus sac cells, such as those from red grapefruit, a homogenizer is needed to break them into a juice slurry with smaller segments. This slurry blends well with the proteoglycan sol, with fewer restrictions on the selection of parameters such as the nozzle diameter and printing speed, and the printed product has high precision. However, the broken juice slurry results in some nutrient loss, especially some water-soluble nutrients. For smaller citrus sac cells, such as those from sweet oranges and mandarins, osmotic dehydration can reduce their water content, shrink their size, and improve their texture. However, the amount added during printing needs to be matched with the nozzle, and the printing speed needs to be reduced. This increase in sac cell content increases the likelihood of them agglomerating in the printing tube, reducing the fluidity of the printing material and thus reducing the aesthetics of the printed sample. Although the probability of particle clogging the nozzle decreases with increasing nozzle diameter, and no obvious line breaks were observed, the precision of the printed sample gradually decreases with increasing nozzle diameter. This invention utilizes different processing methods for citrus sac cells of different sizes to perform heterogeneous 3D printing, resulting in tea snacks with different textures and flavors through heterogeneous distribution.

[0022] Beneficial Effects: ① This invention develops a recyclable proteoglycan-based edible ink for 3D printing by adding a thermally reversible hydrocolloid as a thickener to a protein solution. This ink can be used to design exquisitely shaped food products, maintaining their 3D structure well after printing without significant deformation or collapse within two hours. ② This invention pioneers a material suitable for heterogeneous 3D printing. High-speed homogenization or ultrasonic vacuum-assisted impregnation with ascorbic acid and tea polyphenols to permeate and dehydrate citrus sacs reduces the size of the citrus sac particles, improving their 3D printing properties. Ultrasonic vacuum-assisted impregnation with ascorbic acid and tea polyphenols not only adds a juicy texture to the heterogeneously distributed citrus sac snacks but also enhances the nutritional properties of the heterogeneously printed products containing citrus sacs. ③ This invention obtains nutritious, ready-to-eat snacks with different textures and flavors by selecting different treatment methods for citrus sac particles of different sizes and matching appropriate printing parameters for heterogeneous 3D printing. ④ The raw materials used in this invention are simple and readily available, the preparation method is simple and highly operable, and it can be used as a dessert in high-end tea restaurants, coffee shops, dessert shops and home kitchens as a cold dish. Attached Figure Description

[0023] Figure 1 The thermal reversibility properties of proteoglycan gels with different combinations of carrageenan and konjac gum are characterized.

[0024] Figure 2This is a comparison diagram of the nutritional characteristics of sweet orange and mandarin orange sacs after ultrasonic vacuum-assisted soaking in tea polyphenols and ascorbic acid in Examples 1 and 2.

[0025] Figure 3 This is a rendering of a 3D tea snack product with a heterogeneous distribution containing different amounts of sweet orange cysts, obtained by printing with different nozzle diameters in Example 1.

[0026] Figure 4 This is a 3D rendering of a tea snack product with a non-homogeneous distribution of red grapefruit pulp homogenate containing 5% added amount in Example 3.

[0027] Figure 5 The synergistic effect of hydrophilic colloids on the viscoelasticity of proteoglycan hydrogels: storage modulus (G′) and loss modulus (G″).

[0028] Figure 6 Evaluation of the effect of hydrophilic colloids on the heterogeneous 3D printing of proteoglycan gel: 3% orange juice cyst addition. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to specific embodiments. Example 1:

[0030] A method for preparing a 3D printing snack with heterogeneous distribution of sweet orange cysts, comprising the following steps:

[0031] First, 10 g of whey protein isolate was dissolved in 90 g of distilled water and hydrated overnight to form a uniformly dispersed protein solution with a concentration of 10 wt.%. Carrageenan and konjac gum were then combined with the protein solution to form hydrogels, with mass ratios of carrageenan:konjac gum of 10:0, 7:3, 5:5, 3:7, and 0:10. The total amount of hydrophilic colloid added was 1 wt.% of the protein solution, ensuring complete dissolution. The proteoglycan solution was heated to denature into a hot melt gel, cooled to form a proteoglycan gel, and refrigerated at 4 ℃ for later use. Its thermal reversibility was characterized as follows: Figure 1 As shown in the figure, the increase in colloids improves the adhesion of the protein solution, while the addition of konjac gum changes the sol state of proteoglycans at high temperatures. The addition of a higher content of konjac gum makes the proteoglycan sol thicker, which is not suitable for adding heterogeneous materials for mixing and uniform dispersion. The experiment found that the more suitable ratio of carrageenan to konjac gum is 7:3.

[0032] Sweet orange sac cells were removed from cans and immersed in a 40° Brix xylitol solution containing 0.5 wt.% ascorbic acid and 0.5 wt.% tea polyphenols. The sample and permeate were mixed at a mass ratio of 1:3. First, the cells were dehydrated by ultrasonic permeation for 20 min at a power of 350 W and a vacuum of 0.02 MPa. Then, they were permeated under normal pressure for 160 min. After dehydration, the sac cells were removed and air-dried for later use. The effects of ascorbic acid and tea polyphenol impregnation were measured. It was found that the ascorbic acid and polyphenol contents of the impregnated cells were increased by 1.95 and 1.71 times, respectively, compared to the unimpregnated sac cells. Figure 2 As shown.

[0033] Finally, the prepared proteoglycan gel was melted in a 40 ℃ rotating water bath, and 1 wt.%-5 wt.% sweet orange cyst particles were added. The mixture was stirred and stirred until homogeneous to obtain a proteoglycan mixed ink containing sweet orange cysts. This ink was then filled into the printing tube in a sol state and printed at 36 ℃ using a nozzle diameter of 2.0-3.0 mm, a nozzle movement speed of 12 mm / s, and an ejection speed of 23 mm / s. 3 / s, fill rate 90%, print quality as shown Figure 3 As shown. The printing accuracy of products containing 3% sweet orange sac cells at a nozzle diameter of 2.5 mm can reach 88%. This ready-to-eat product is rich in ascorbic acid and tea polyphenols, has a sweet and sour taste, and the sweet orange sac cells burst with juice when chewed. It is also highly nutritious and can be used in high-end tea restaurants, coffee shops, dessert shops, and home kitchens. Example 2:

[0034] A method for preparing a 3D printing pastry with heterogeneous distribution of tangerine sac cells, comprising the following steps:

[0035] First, 15 g of peanut protein isolate was dissolved in 85 g of distilled water and hydrated overnight to form a uniformly dispersed protein solution of 15 wt.%. Carrageenan and konjac gum were then combined with the protein solution to form hydrogels, using a gradient mass ratio of carrageenan:konjac gum of 10:0, 7:3, 5:5, 3:7, and 0:10. The total amount of hydrocolloid added was 1 wt.% of the protein solution, ensuring complete dissolution. The proteoglycan solution was heated to denature it into a hot melt gel, cooled to form a proteoglycan gel, and refrigerated at 4°C for later use.

[0036] Satsuma mandarin orange spores were extracted from canned goods and immersed in a 40° Brix xylitol solution containing 0.5 wt.% ascorbic acid and 0.5 wt.% tea polyphenols. First, they were dehydrated by ultrasonic permeation for 20 minutes under a vacuum of 0.02 MPa at 300 W, then permeated under normal pressure for 160 minutes before being removed and air-dried. The effects of the impregnation on ascorbic acid and tea polyphenols were measured, revealing that the ascorbic acid and polyphenol content of the impregnated satsuma mandarin orange spores increased by 1.94 and 1.86 times, respectively, compared to the unimpregnated satsuma mandarin orange spore particles. Figure 2 As shown.

[0037] The prepared proteoglycan gel was melted in a 40 °C rotary water bath, and 2 wt.% of Satsuma mandarinii cysteine ​​particles were added. The mixture was stirred and stirred until homogeneous to obtain a proteoglycan-containing ink. This ink, in its sol state, was filled into a printing tube and printed at 36 °C using a 2.5 mm nozzle diameter, a nozzle movement speed of 12 mm / s, and a discharge velocity of 23 mm / s. 3 / s, with a filling rate of 90%. Among them, the accuracy of the printed products with 2 wt.% mandarin orange sac cells at a nozzle diameter of 2.5 mm can reach 85%. This ready-to-eat product after printing is rich in ascorbic acid and polyphenols, has a sweet and sour taste, and the mandarin orange sac cells burst with juice when chewed. It is also rich in nutrients and can be used in high-end tea restaurants, coffee shops, dessert shops and home kitchens. Example 3:

[0038] A method for preparing a 3D printing pastry with heterogeneous distribution of red grapefruit cysts, comprising the following steps:

[0039] First, 10 g of whey protein isolate was dissolved in 90 g of distilled water and hydrated overnight to form a uniformly dispersed protein solution with a concentration of 10 wt.%. Carrageenan and konjac gum were then combined with the protein solution to form hydrogels, with a gradient mass ratio of carrageenan:konjac gum of 10:0, 7:3, 5:5, 3:7, and 0:10. The total amount of hydrocolloid added was 1 wt.% of the protein solution. The proteoglycan solution was heated to denature it into a hot melt gel, cooled to form a proteoglycan gel, and refrigerated at 4 ℃ for later use. Its thermal reversibility was characterized as follows: Figure 1 As shown, the addition of colloids improves the adhesion of the protein solution, while the addition of konjac gum changes the sol state of proteoglycans at high temperatures. The addition of a higher content of konjac gum makes the proteoglycan sol thicker. This state is not suitable for adding heterogeneous materials for mixing and uniform dispersion. The experiment found that the more suitable ratio of konjac gum to konjac gum is 7:3.

[0040] Whole grapefruit pith particles were removed from the can, rinsed with water, and surface moisture was removed. A 40° Brix xylitol solution was added at a 1:1 mass ratio, and a grapefruit pith homogenate was prepared using a high-speed shear homogenizer. The prepared proteoglycan gel was melted in a 40°C rotary water bath, and 5 wt.% of the grapefruit pith homogenate was added. The mixture was stirred until homogenized, yielding a proteoglycan-containing ink with grapefruit pith homogenate. This ink was then filled into the printing tube in sol form and printed at 36°C using a 1.5 mm nozzle diameter, a nozzle movement speed of 15 mm / s, and a discharge speed of 23 mm / s. 3 / s, with a filling rate of 90%. The printing accuracy of products containing 5 wt.% red grapefruit pulp homogenate at a nozzle diameter of 1.5 mm can reach 92%, as shown in Figure 4. This ready-to-eat printed product is rich in broken red grapefruit pulp. Although the texture of the non-homogeneous fruit pieces bursting with juice is not obvious, it can also be used in coffee shops, dessert shops, and home kitchens.

[0041] Comparative Example: Comparative Experiment on the Effect of Hydrophilic Colloidal Interactions on the Printing Effect of Proteoglycans

[0042] Comparative Example 1:

[0043] Compared with Example 1, this comparative example dissolves 10 wt.% whey protein isolate in water and hydrates it overnight, fixes the amount of hydrophilic colloid added at 1 wt.%, and adds only carrageenan to the protein solution to prepare proteoglycan hydrogels. The viscoelasticity of the hydrogels and the effect of adding orange juice cyst particles for heterogeneous printing are evaluated.

[0044] Comparative Example 2:

[0045] Compared with Example 1, this comparative example dissolves 10 wt.% whey protein isolate in water and hydrates it overnight, fixes the amount of hydrophilic colloid added at 1 wt.%, and adds only konjac gum to the protein solution to prepare proteoglycan hydrogels, evaluating the viscoelasticity of the hydrogels formed and the effect of adding orange juice cyst particles for heterogeneous printing.

[0046] The preferred conditions in Examples 1-3 were applied (protein concentration of 10 wt.%, carrageenan to konjac gum mass ratio of 7:3; orange juice cysts added at 3 wt.%); the proteoglycan gel melting temperature was maintained at 35-45 ℃, the holding time at 15-30 min, and the mixing time after adding citrus cysts was 5-10 min; the printing temperature was 35-37 ℃, the nozzle diameter was 2.0-3.0 mm, the nozzle movement speed was 10-15 mm / s, and the discharge speed was 22-25 mm / s). 3The viscoelasticity of proteoglycan hydrogels prepared with a fill rate of 70%-90% ( / s) was evaluated by minimum strain, and the printing effect of heterogeneous proteoglycan printing ink containing cysts was evaluated.

[0047] Depend on Figure 5 It can be seen that when the initial strain is relatively small (0.1-10%), the storage modulus G' of all samples is greater than the loss modulus G”, indicating that the proteoglycan hydrogel formed after adding the colloid exhibits elastic characteristics. With the increase of strain (10-100%), the storage modulus G' decreases, while the loss modulus G” continuously increases, and eventually the intersection of the two determines the yield stress. This indicates that under large strain, the network structure of the proteoglycan hydrogel is disrupted, and the hydrogel will exhibit more liquid properties. The mixture of carrageenan and konjac gum at a mass ratio of 7:3 (Example 1) showed the highest yield stress value (1290 Pa) compared to the addition of carrageenan alone (Comparative Example 1) and konjac gum alone (Comparative Example 2). This indicates that the mixture of carrageenan and konjac gum physically forms a denser network structure, which is beneficial for improving the stability of the printed products. Figure 6 It can be seen that the carrageenan and konjac gum mixed at a mass ratio of 7:3 (Example 1) exhibit good extrusion smoothness, thus showing the best printing effect. However, the printing ink with konjac gum added alone (Comparative Example 2) has poor dispersion of orange juice cell particles due to the non-thermally reversible gel properties. During extrusion, the particles break due to aggregation, resulting in poor printing effect.

Claims

1. A 3D printing method for citrus sac-based snacks with heterogeneous distribution, characterized in that, The process includes the following steps: (1) Preparation of thermally reversible proteoglycan gel: Dissolve protein powder in water, stir and hydrate overnight to form a uniformly dispersed protein solution with a protein concentration of 10-20 g / 100 mL; add hydrophilic colloid and stir to completely dissolve it in the protein solution, with a total amount of hydrophilic colloid added of 0.5-2 g / 100 mL; heat the proteoglycan solution to denature it into a hot melt, cool it to form a proteoglycan gel and refrigerate it at 4 ℃ for later use; the protein powder is any one of whey protein isolate, peanut protein isolate, mung bean protein, walnut protein, and soy protein isolate; the hydrophilic colloid is carrageenan and konjac gum, with a mass ratio of 7:3; the thermal denaturation temperature of the proteoglycan solution is 70-90 ℃, and the heating duration is 10-30 min. (2) Pretreatment of citrus sac granules: Add xylitol solution to citrus sac granules and prepare citrus pulp homogenate using a high-speed shear homogenizer; or, immerse citrus sac granules in xylitol solution for osmotic dehydration to maintain the integrity of the granules, and use ultrasonic vacuum equipment to assist the osmotic dehydration process; or, immerse citrus sac granules in xylitol solution with added tea polyphenols or ascorbic acid for osmotic dehydration to maintain the integrity of the granules while enriching their dietary nutrients, with the addition amounts of tea polyphenols and ascorbic acid being 0.5-1 liters respectively. g / 100mL, and use ultrasonic vacuum equipment to assist the permeation and dehydration process; the xylitol concentration of the above xylitol solution permeation treatment is 30-50°Brix, and the material-liquid mass ratio is 1:(2-5); (3) Add citrus cyst particles: melt the proteoglycan gel prepared in step (1) in a rotating water bath, add the citrus pulp homogenate or dehydrated citrus cyst particles prepared in step (2), stir and mix them evenly with the proteoglycan to obtain a proteoglycan mixed ink containing citrus cysts; the amount of citrus pulp homogenate or dehydrated citrus cyst particles added is 1wt.%-10% of the proteoglycan gel obtained in step (1). wt.%; (4) 3D printing: The proteoglycan mixture ink containing citrus cysts obtained in step (3) is filled into the printing tube in a sol state. After setting the printing parameters, printing is performed. The 3D printing parameters include: printing temperature of 35-37℃, nozzle diameter of 2.0-3.0mm, nozzle moving speed of 10-15mm / s, and material output speed of 22-25mm. 3 / s, with a fill rate of 70%-90%.

2. The 3D printing method for heterogeneous distribution of citrus sac cells as described in claim 1, characterized in that, In step (2), the size of the citrus cyst particles after being crushed by a high-speed shear homogenizer is between 0.5-1.5cm. The prepared crushed citrus cyst particles are placed in a refrigerator at 4℃ for later use.

3. The 3D printing method for heterogeneous distribution of citrus sac cells as described in claim 1, characterized in that, In step (2), the power of ultrasonic treatment is 150-450 W and the treatment time is 10-30 min.

4. The 3D printing method for heterogeneous distribution of citrus sac cells as described in claim 1, characterized in that, In step (2), the vacuum degree of the vacuum treatment is 0.01-0.05MPa, and the treatment time is 10-30min; the ultrasonic vacuum starts and ends at the same time, and the treatment time is 10-30min, followed by continuous permeation at room temperature and atmospheric pressure for 60-180min.

5. The 3D printing method for heterogeneous distribution of citrus sac cells as described in claim 1, characterized in that, In step (3), the proteoglycan gel is kept at a temperature of 35-45°C in a rotating water bath for 15-30 minutes, so that the solid proteoglycan gel becomes a liquid sol.

Images