Gel, method and application of 3D printing food suitable for infants and old people

Abstract

The invention relates to the technical field of 3D printing food, in particular to gel suitable for 3D printing food of infants and old people, a method and application. The gel is prepared by the method. The method comprises the following steps: adding yeast protein and whey protein isolate into water, dissolving and uniformly mixing to obtain a protein aqueous solution; and adding walnut oil into the protein aqueous solution, dispersing and uniformly mixing to obtain the gel. The application comprises application of the gel in 3D printing ink and application of the gel in 3D printing food. The gel with centrifugal stability, thermal stability and oxidation stability can be prepared, and the gel is suitable for processing 3D printing food.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printed food, and in particular to a gel, method and application suitable for 3D printed food for infants and the elderly. Background Art

[0002] In recent years, there has been an increasing focus on the special diet and dietary nutritional needs of people with dysphagia. Dysphagia is defined as a physiological difficulty or disorder in the process of chewing and swallowing food (i.e., the mouth, pharynx, and / or esophagus), which results in a delayed obstruction in the transfer of food lumps from the oral pharynx to the esophagus. The most common groups of people with dysphagia are infants, the elderly, and patients recovering from surgery, who have difficulty swallowing regular food due to weak tongue and oral muscles, tooth loss, and other physical illnesses such as stroke. Therefore, it is easy for people with dysphagia to have problems with insufficient food intake and nutritional deficiencies.

[0003] Related studies have shown that the texture, size and shape of food have been identified as factors associated with dysphagia. However, the diet of people with dysphagia is usually paste and mashed food, which is unpopular because of poor appeal and lack of appetite. An effective way to increase food intake in people with dysphagia is to make easy-to-swallow foods more attractive. 3D printed food technology has great potential in enhancing food appearance and texture regulation.

[0004] At present, most of the research focuses on the printing accuracy and printing stability of 3D printed food. For example, hydrophilic colloids (such as xanthan gum, carrageenan) or enzymes (such as TGase, etc.) are added to the printing matrix to modify the material to improve the rheological properties of the material and thus improve its printing accuracy. Although this can make food more attractive, the nutritional characteristics of 3D printed food have not attracted much attention. At present, there are few reports on the research of easy-to-swallow 3D printed foods with nutritional fortification (such as lipid fortification), which to a certain extent limits the diversified nutritional needs of people with dysphagia and the development of personalized nutritional customization of 3D printed foods.

[0005] In summary, it is necessary to develop a gel, method and application suitable for 3D printed food for infants and the elderly to solve the problem of insufficient nutritional fortification of existing 3D printed foods. Summary of the invention

[0006] The purpose of the present invention is to provide a gel, method and application suitable for 3D printing food for infants and the elderly. The specific technical scheme is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a gel suitable for 3D printing food for infants and the elderly, comprising:

[0008] Step S1, adding yeast protein and whey protein isolate into water, dissolving and mixing to prepare a protein aqueous solution; wherein the mass percentage of the yeast protein in the protein aqueous solution is 1%-5%; the mass percentage of the whey protein isolate in the protein aqueous solution is 1%-3%;

[0009] Step S2, adding walnut oil to the protein aqueous solution, dispersing and mixing to obtain a gel; wherein the volume of the walnut oil accounts for 75%-80% of the volume of the gel.

[0010] Optionally, in step S2, the dispersion and mixing is carried out at a dispersion stirring speed of 10000 rpm-15000 rpm, and the dispersion time is 120-240 s.

[0011] Optionally, the yeast protein is extracted from Saccharomyces cerevisiae.

[0012] In a second aspect, the present invention provides a gel suitable for 3D printing food for infants and the elderly, which is prepared by the method for preparing the gel suitable for 3D printing food for infants and the elderly.

[0013] In a third aspect, the present invention provides a gel suitable for 3D printing food for infants and the elderly and its use in 3D printing ink.

[0014] Optionally, in the 3D printing ink, the mass percentage of the gel is 5% to 7.5% of the basic raw material.

[0015] Optionally, the basic raw material used in the 3D printing ink includes rice flour.

[0016] In a fourth aspect, the present invention provides an application of a gel suitable for 3D printing food for infants and the elderly in 3D printing food.

[0017] Optionally, in the 3D printed food, the mass percentage of the gel is 5% to 7.5% of the basic raw material.

[0018] Optionally, the basic raw material of the 3D printed food includes rice flour; and the shape of the 3D printed food includes a cylindrical shape and a petal shape.

[0019] The application of the technical solution of the present invention has at least the following beneficial effects:

[0020] (1) The method for preparing a gel suitable for 3D printed food for infants and the elderly provided by the present invention can prepare a gel with centrifugal stability, thermal stability and oxidative stability, which is suitable for processing 3D printed food.

[0021] (2) The application of the gel suitable for 3D printing food for infants and the elderly provided by the present invention in 3D printing ink can ensure that the printed sample has high-definition resolution and shape accuracy by controlling the mass percentage of the gel in the 3D printing ink to 5% to 7.5%.

[0022] (3) The application of the gel suitable for 3D printed food for infants and the elderly provided by the present invention in 3D printed food, by controlling the mass percentage of the gel in the basic raw materials of the 3D printed food to 5% to 7.5%, can not only achieve the diversification and stability of the appearance of the 3D printed food, but also solve the problem of insufficient nutritional fortification of the existing 3D printed food, so that the 3D printed food can not only meet the diversified nutritional needs, but also realize personalized nutritional customization. In addition, the gel is applied to the rice flour 3D printed food to create a lipid-fortified rice flour product with richer shapes, strengthen the content of lipids and proteins in traditional cereal matrix foods, improve the nutritional value of traditional paste rice flour, and prepare a 3D printed food suitable for people with dysphagia. In addition, the 3D printed sample obtained by applying the gel to the rice flour 3D printed food is defined as a level 6 soft, bite-sized dysphagia food, which is very suitable for people with dysphagia.

[0023] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 is a comparison chart of the gel sample prepared in Example 1 before and after the centrifugal stability test;

[0026] Figure 2 is a comparison chart of the gel sample prepared in Example 1 before and after the thermal stability test;

[0027] Figure 3 This is the 3D printed cylinder sample image of the blank group;

[0028] Figure 4 This is the 3D printed cylinder sample picture of the control group;

[0029] Figure 5 This is a picture of the 3D printed cylinder sample of test group 1;

[0030] Figure 6 This is a picture of the 3D printed cylinder sample of test group 2;

[0031] Figure 7 This is a sample image of the 3D printed petal model of test group 1;

[0032] Figure 8 This is a picture of the 3D printed cylinder sample of test group 3;

[0033] Fig. 9 This is a picture of the 3D printed cylinder sample of test group 4;

[0034] Fig.10 This is the cross drop test image of the 3D printed sample;

[0035] Fig.11 This is the spoon tilt test image of the 3D printed sample;

[0036] Fig.12 This is a picture of the compression fork test of the 3D printed sample. DETAILED DESCRIPTION

[0037] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 belong to the scope of protection of the present invention.

[0038] Embodiment 1:

[0039] A method for preparing a gel suitable for 3D printing food for infants and the elderly, characterized by comprising:

[0040] Step S1, adding yeast protein and whey protein isolate into water, dissolving and mixing to prepare a protein aqueous solution; wherein the mass percentage of the yeast protein in the protein aqueous solution is 5%; the mass percentage of the whey protein isolate in the protein aqueous solution is 3%;

[0041] Step S2, adding walnut oil (purchased from Hunan Yingshi Nutrition Food Co., Ltd.) into the protein aqueous solution, and obtaining a gel by dispersing and mixing; wherein the volume of the walnut oil accounts for 75% of the volume of the gel.

[0042] In step S2, the dispersion and mixing are completed by using a high-speed disperser (T18 German IKA), wherein the dispersion and stirring speed is controlled to be 15000 rpm and the dispersion time is 120 s.

[0043] The yeast protein is extracted from brewer's yeast (protein greater than 80%, water 6.9%, fat 6.0%), and is provided by Hubei Yichang Anqi Yeast Co., Ltd., China. The whey protein isolate is provided by Arla Foods Ingredients Group.

[0044] The prepared gel was photographed with a digital camera (model: EOS 70D, manufactured by Canon (China) Co., Ltd.) and then stored in a 4°C refrigerator for later use.

[0045] The gel prepared in Example 1 was sampled for centrifugal stability test, thermal stability test and oxidation stability test.

[0046] The centrifugal stability test method is as follows: 30 g of the gel sample prepared in Example 1 was centrifuged at 10,000 rpm for 45 min at 4°C, and its centrifugal stability was displayed by observing the oil-water separation. Figure 1 The centrifugal device used was a desktop centrifuge, model Microfuge20R, manufactured by Beckman Coulter, Inc., USA.

[0047] Depend on Figure 1 It is known that after centrifugation of the gel sample prepared in Example 1, no instability of oil-water separation occurs, indicating that the water-in-oil structure of the gel remains intact and has good centrifugal stability.

[0048] The thermal stability test method is as follows: 30 g of the gel sample prepared in Example 1 is heated in a high pressure steam sterilizer at 121° C. for 30 min, and its thermal stability is displayed by observing the macroscopic morphology of the gel, see Figure 2 .

[0049] Depend on Figure 2 It is known that after the thermal stability test of the gel sample prepared in Example 1, no obvious structural damage occurs, indicating that the gel has good thermal stability.

[0050] The oxidation stability test method is as follows: 30 g of the gel sample prepared in Example 1 was cultured at 37° C. for 15 days, and the oxidation of the gel was measured. The test results are shown in Table 1. The specific measurement method is as follows:

[0051] Determination of primary lipid oxidation products (measured in terms of lipid hydroperoxide (LH) content): 0.2 mL of gel sample and 1.5 mL of 2-propanol / isooctane (1:3, v / v) were mixed and vortexed for 3 min (vortexing was performed using a vortex oscillator, model 2009-JP, manufactured by Thermo Fisher Scientific China Co., Ltd.) to obtain a mixed solution. The mixed solution was centrifuged at 8000 rpm for 5 min, 0.2 mL of the supernatant was taken, 2.8 mL of methanol / 1-butanol (2:1, v / v) was added thereto, and 15 μL of ammonium thiocyanate and Fe were added respectively. 2+ Solution. After 20 minutes of dark reaction, the absorbance was measured at 510 nm. 2 O 2 The absorbance was calculated based on the standard curve to obtain the content of lipid hydroperoxide (LH).

[0052] Determination of secondary lipid oxidation products (in terms of malondialdehyde content): 0.2 mL of gel sample, 1.8 mL of deionized water and 4 mL of 0.37 wt% thiobarbituric acid (TBA) solution were mixed to form a first mixed solution; 15 g of trichloroacetic acid was added to 100 mL of HCl solution (the molar concentration of the HCl solution was 0.25 mol / L) to form a second mixed solution after mixing. The first mixed solution and the second mixed solution were mixed to form a mixed solution, which was heated at 100°C for 10 min and then cooled to 25°C. The mixed solution was centrifuged at 8000 rpm for 5 min, and the supernatant was taken, and the absorbance was measured at a wavelength of 532 nm. The malondialdehyde content was obtained by calculating the absorbance according to the standard curve (1,1,3,3-tetraethoxypropane).

[0053] According to the oxidative stability test method, walnut oil (purchased from Hunan Yingshi Nutrition Food Co., Ltd.) was used to replace the gel sample prepared in Example 1 as a control group to complete the oxidative stability test. The test results are shown in Table 1 (in Table 1, superscripts a and b are significance analysis symbols, which are commonly used representation methods in statistics. If both are a, it proves that there is no significant difference between the two groups of results. If a and b appear at the same time, it means that there is a significant difference between the two groups, indicating that the method has an improvement effect).

[0054] Table 1 Oxidative stability test data of walnut oil and gel samples

[0055] Group Lipid hydroperoxide mmol / kg (weight percentage) Malondialdehyde (μmol / kg) Walnut Oil <![CDATA[333.10±3.68 a ]]> <![CDATA[47.88±1.22 a ]]> Gel samples <![CDATA[186.01±4.67 b ]]> <![CDATA[34.69±0.66 b ]]>

[0056] From the data in Table 1, it can be seen that compared with walnut oil, the content of lipid hydroperoxides in the gel sample prepared in Example 1 is 186.01±4.67mmol / kg (weight percentage), which is significantly lower than the lipid hydroperoxide content of walnut oil in the control group of 333.10±3.68mmol / kg (weight percentage), which indicates that the gel sample prepared in Example 1 can effectively improve the oxidative stability of the oil phase. In order to analyze the oxidative stability of FOG gel, the data in Table 1 also measured the content of malondialdehyde, a secondary product of lipid oxidation. Specifically, the malondialdehyde content in the gel sample prepared in Example 1 is 34.69±0.66μmol / kg, which is significantly lower than the malondialdehyde content of walnut oil in the control group of 47.88±1.22μmol / kg, which indicates that the gel sample prepared in Example 1 has the effect of inhibiting lipid oxidation. Among them, the main reason why the gel sample inhibits lipid oxidation is that lipid oxidation mainly occurs at the contact surface between oil droplets and oxygen, and yeast protein particles will form a dense protein film on the surface of oil droplets. This film can prevent walnut oil from contacting oxidants, thereby improving the oxidative stability of the gel sample, which is beneficial to the application of gel samples in grain-based products.

[0057] The gel prepared in Example 1 is used in 3D printing ink, and the specific application is as follows:

[0058] As shown in Table 2, first, in each test group, 200 g of rice flour (purchased from Hunan Yingshi Nutrition Food Co., Ltd.) was dissolved in 400 g of pure water, the water temperature was kept constant at 40°C, and a uniform paste was formed after slow stirring for 1 min; secondly, different masses of the gel prepared in Example 1 were added to each group of pastes, and stirred for 2 min to form a series of 3D printing inks with different gel mass percentages. No gel was added to the blank group. Walnut oil was used to replace the gel in the control group.

[0059] Table 2 Formulations of 3D printing inks in different test groups

[0060] Group Rice flour(g) Purified water(g) Gel(g) Walnut oil(g) Blank group 200 400 0 0 Control group 200 400 0 10 Test group 1 (gel 5%) 200 400 10 0 Test Group 2 (Gel 7.5%) 200 400 15 0 Test group 3 (gel 10%) 200 400 20 0 Test Group 4 (Gel 12.5%) 200 400 25 0

[0061] The printing inks of different test groups in Table 2 were 3D printed using a nozzle-injector-based SHINNOVE-D2 extrusion 3D printer (specifically, a dual-nozzle food 3D printer, model FOODBOT-D2, manufactured by Hangzhou Shiyin Technology Co., Ltd.), and the printing temperature was 25±1°C. A solid cylinder (height 30mm×diameter 25mm) was designed using CAD software; the printing parameters were set as follows: the filling mode was linear and the filling density was 80%; other printing parameters were: the nozzle height was 1.60mm, the nozzle diameter was 1.20mm, and the nozzle movement speeds during printing and retraction were 30mm / s and 30mm / s, respectively. In addition, a petal model (side length of 15mm and height of 10mm) was designed using CAD software, and the printing parameter settings were adjusted. Specifically, the filling mode was "right-angle linear filling structure", the filling density was 80%, the nozzle height was 1.60mm, the nozzle diameter was 1.20mm, and the nozzle movement speeds during printing and retraction were 30mm / s and 30mm / s, respectively. The 3D printing results are shown in the figure. Figure 3-Figure 9 Among them, the petal model 3D printing sample only provides Fig. 9 , that is, adding 5% by mass of gel to the rice flour; while the mechanical strength of adding 10% and 12.5% ​​by mass of gel to the rice flour is weak and insufficient to support the deposited petal model structure.

[0062] Depend on Figure 3-Figure 4 It is known that in the blank group and the control group, no gel was added, and the printed cylindrical samples showed expansion of the printing lines (i.e., the blank group) and collapse of the printing lines (i.e., the control group), respectively, which failed to take into account both printing accuracy and printing stability. Figure 5-Figure 7It is known that after adding 5% and 7.5% gel by mass to rice flour, the printed samples have high-definition resolution and shape accuracy, which is a 3D printing formula that can take into account both printing accuracy and printing stability. This shows that adding 5% and 7.5% gel by mass to rice flour has suitable mechanical properties and can support high-precision 3D printing. Figure 8-Figure 9 It is known that adding 10% and 12.5% ​​gel by mass to rice flour shows weak mechanical strength, and the printed cylindrical samples show line collapse (i.e. test group 3 (gel 10%)) and print line expansion (i.e. test group 4 (gel 12.5%)), which indicates that gel with too high a mass percentage is not enough to support high-precision 3D printing of rice flour. Therefore, adding 5% and 7.5% gel has a good 3D printing improvement effect on rice flour.

[0063] The gel prepared in Example 1 is applied in 3D printed food, and the specific application is as follows:

[0064] Add 5% by mass of the gel prepared in Example 1 to 200g of the basic raw material rice flour, then add 400g of pure water, mix well to obtain 3D printing ink, and obtain 3D printed samples after 3D printing. The 3D printed samples were subjected to the International Dysphagia Food Standard Test (i.e., International Dysphagia Diet Standardization Initiative, IDDSI.July, 2019). The International Dysphagia Food Standard Test Framework divides food into 8 levels (i.e., 0-7 levels). In order to clarify the swallowing level of 3D printed samples under the International Dysphagia Food Standard Test Framework, the 3D printed samples were sampled and subjected to the fork drop test, spoon tilt test and fork pressure test (test methods see International Dysphagia Diet Standardization Initiative, IDDSI.July, 2019), and the test results are shown in the table below. Figure 10-12 First, the fork drop test can observe the flow behavior of the 3D printed sample on the fork. Then, the spoon tilt test is used to observe the sliding of the 3D printed sample on the spoon to evaluate the adhesion and cohesion of the printed sample. Finally, the compression fork test is performed to observe the appearance of the 3D printed sample after compressing the 3D printed sample with a compression handle until the tip of the thumb nail turns white.

[0065] See also Fig.10 ,During the fork drop test, the 3D printed samples were able to stably accumulate on the fork without dripping through the fork tip gap, which indicates that the 3D printed samples can be classified as potential transitional foods (grades 5-7) within the IDDSI framework.

[0066] See also Fig.11In the spoon tilt test, the 3D printed sample had enough adhesion and cohesion to maintain its shape on the spoon. When the spoon was tilted and slightly shaken, the 3D printed sample easily slid off the spoon. This is ideal for difficult-to-swallow foods, making it easy to swallow without sticking to the tongue or pharynx and causing swallowing difficulties.

[0067] See also Fig.12 In the fork pressure test, the pressure that usually causes the tip of the thumb nail to turn white is about 17kPa, which is similar to the pressure generated when the tongue squeezes the food mass when swallowing. The results show that when the tip of the thumb nail turns white, the fork has an extrusion deformation effect on the 3D printed sample, and the sample tissue morphology is significantly damaged after the fork is pulled out, indicating that the sample can be easily crushed by the tongue when swallowing, which is defined as a level 6 soft, bite-sized dysphagia food.

[0068] In summary, under the IDDSI framework, the 3D printed sample with 5% gel added can be defined as a level 6 soft and bite-sized dysphagia food. The above results show that the 3D printed sample is suitable for people with dysphagia problems, such as the elderly and infants, and the addition of the gel prepared in Example 1 further improves its lipid nutritional properties.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a gel suitable for 3D printing food for infants and the elderly, characterized in that: include: Step S1, adding yeast protein and whey protein isolate into water, dissolving and mixing to prepare a protein aqueous solution; wherein the mass percentage of the yeast protein in the protein aqueous solution is 1%-5%; the mass percentage of the whey protein isolate in the protein aqueous solution is 1%-3%; Step S2, adding walnut oil to the protein aqueous solution, dispersing and mixing to obtain a gel; wherein the volume of the walnut oil accounts for 75%-80% of the volume of the gel.

2. The method for preparing a gel suitable for 3D printed food for infants and the elderly according to claim 1, characterized in that: In step S2, the dispersion and mixing is carried out at a dispersion stirring speed of 10000 rpm to 15000 rpm, and the dispersion time is 120 to 240 s.

3. The method for preparing the gel suitable for 3D printing food for infants and the elderly according to claim 1, characterized in that: The yeast protein is extracted from Saccharomyces cerevisiae.

4. A gel suitable for 3D printing food for infants and the elderly, characterized in that: The gel is prepared by the method for preparing 3D printed food for infants and the elderly as described in any one of claims 1 to 3.

5. Use of the gel suitable for 3D printing food for infants, young children and the elderly as claimed in claim 4 in 3D printing ink.

6. The use of the gel suitable for 3D printing food for infants and the elderly in 3D printing ink according to claim 5, characterized in that: In the 3D printing ink, the mass percentage of the gel is 5% to 7.5% of the basic raw material.

7. The use of the gel suitable for 3D printing food for infants and the elderly in 3D printing ink according to claim 5, characterized in that: The basic raw material used in the 3D printing ink includes rice flour.

8. Use of the gel suitable for 3D printing food for infants, young children and the elderly as claimed in claim 4 in 3D printing food.

9. The use of the gel suitable for 3D printing food for infants and the elderly according to claim 8 in 3D printing food, characterized in that: In the 3D printed food, the mass percentage of the gel is 5% to 7.5% of the basic raw material.

10. The use of the gel suitable for 3D printing food for infants and the elderly according to claim 9 in 3D printing food, characterized in that: The basic raw material of the 3D printed food includes rice flour; the shape of the 3D printed food includes a cylindrical shape and a petal shape.

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