High-strength starch-fatty acid composite gel as well as preparation method and application thereof

Abstract

The invention discloses a high-strength starch-fatty acid composite gel preparation method, which comprises: 1, mixing starch and fatty acid to obtain mixed starch, extruding the mixed starch through a twin-screw extruder, drying, grinding, and screening to obtain a potato starch-stearic acid composite; step 2, heating the potato starch-stearic acid compound through an RVA starch procedure, and completely gelatinizing the potato starch-stearic acid compound to obtain starch gel; the printing precision of the 3D printing product obtained through the method is greatly improved and can reach 90% or above. The production cost is low, the operation is simple, the environmental pollution is small, and the requirements of the modern food industry are met.

Description

Technical Field

[0001] This invention relates to the field of food starch modification technology, and in particular to high-strength starch-fatty acid composite gel, its preparation method, and its application. Background Technology

[0002] 3D food printing, as an innovative technology, is changing traditional food manufacturing methods and becoming an emerging trend. 3D printing technology is a form of additive manufacturing that uses the layer-by-layer deposition of one or more edible inks to build materials with specific shapes, and can also customize food according to individual needs.

[0003] 3D food printing allows for the modification of the texture, shape, and consistency of food, making it more palatable. Starch is considered a good ingredient choice for developing edible inks for 3D food printing applications because it is abundant, inexpensive, easy to use, and can form gels suitable for formulating edible inks. However, natural starch has drawbacks such as high gelatinized viscosity, poor shear and heat resistance, and weak gelling properties. The limited thermal stability and mechanical properties of pure starch gels often restrict their application as edible inks.

[0004] Therefore, providing a high-strength starch gel and its preparation method is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the present invention discloses a high-strength starch-fatty acid composite gel, its preparation method and application, to solve the problems of poor gel strength and limited functionality in gel foods.

[0006] First, this invention provides a method for preparing a high-strength starch-fatty acid composite gel, comprising: Step 1: Mix starch and fatty acids to obtain mixed starch. Extrude the mixed starch through a twin-screw extruder, dry, grind, and sieve to obtain potato starch-stearic acid complex. Step 2: The potato starch-stearic acid complex is heated through the RVA starch program to completely gelatinize it and obtain starch gel.

[0007] Preferably, the mass ratio of the fatty acid to starch is 1-3:100.

[0008] Preferably, the fatty acid in step 1 is in powder form with a particle size of 80 mesh.

[0009] Preferably, the screw speed of the twin-screw extruder is 110~240 rpm, and the temperature of the cooking zone of the twin-screw extruder is 75-110 ℃.

[0010] Preferably, the drying and grinding process parameters in step 1 are: drying in an oven at 45 ℃ for 48 h, then grinding with a grinding mill and passing through a 100-mesh sieve.

[0011] Preferably, the fatty acids include stearic acid, palmitic acid and / or lauric acid; the starch is sweet potato starch, potato starch and / or cassava starch.

[0012] Preferably, the potato starch-stearic acid complex described in step 2 is heated using the RVA starch program, wherein 3.0 g of starch and 25 mL of distilled water are placed in an aluminum can and the RVA starch program is run.

[0013] In addition, the present invention also provides a high-strength starch-fatty acid composite gel prepared by the above preparation method.

[0014] Finally, the present invention also provides the application of the high-strength starch-fatty acid composite gel for preparing edible ink for printing food structures.

[0015] This invention provides a high-strength starch-fatty acid composite gel, its preparation method, and its applications. The method yields a high-strength starch gel. The extrusion process in this invention promotes the composite of starch and fatty acids. The resulting gel is used for 3D printing, significantly improving the printing accuracy of 3D printed products to over 90%. This invention enriches our understanding of starch structure while fully stimulating its functional applications. It features low production costs, simple operation, and minimal environmental pollution, meeting the needs of the modern food industry.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the disclosure of the present invention. Attached Figure Description

[0017] Figure 1 These are the appearance diagrams of Embodiments 1-3 and the comparative examples of the present invention; Figure 2 These are scanning electron microscope images of Embodiments 1-3 and the comparative example of the present invention; Figure 3 The XRD patterns are of Examples 1-3 and the blank example of the present invention; Figure 4 The images show the printing effects of Embodiments 1-3 and the blank example in 3D printing. Detailed Implementation

[0018] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of systems consistent with some aspects of the invention as detailed in the appended claims.

[0019] This invention provides a method for preparing a high-strength starch-fatty acid composite gel, comprising the following steps: 1) Mix starch and fatty acids, then extrude them using a twin-screw extruder, dry, grind, and sieve to obtain composite starch.

[0020] 2) The composite starch is heated through the RVA starch program to completely gelatinize it, resulting in a high-strength starch-fatty acid composite gel. This invention uses starch as a base material and releases amylose from the starch through extrusion, which is more conducive to the formation of starch-fatty acid complex and thus forms a functional composite starch.

[0021] The composite starch gel obtained by the method of this invention improves the functional properties of starch through non-covalent interactions, resulting in a denser and more uniform microstructure.

[0022] The mass ratio of fatty acids to starch in step 1) is 1~3:100, preferably 1.5~2.5:100, and most preferably 2:100.

[0023] In step 1), the fatty acids are ground and passed through an 80-mesh sieve, then mixed with starch and extruded using a twin-screw extruder.

[0024] The material moisture content of the twin-screw extruder described in step 1) is 35%~55%, and the screw speed is 110~240 rpm, preferably 140~200 rpm, and most preferably 170 rpm; The temperature of the cooking zone is 75~110 ℃, preferably 75~95 ℃, and more preferably 85 ℃; After extrusion by the twin-screw extruder in step 1), the material is dried in an oven at 45 ℃ for 48 h, then ground by a grinding mill and passed through a 100-mesh sieve.

[0025] Step 2) Take 3.0 g of starch and 25 mL of distilled water in an aluminum can and run the RVA starch program.

[0026] Step 2) provides the application of high-strength starch-fatty acid composite gel, which is applied to 3D printed food. The obtained high-strength starch-fatty acid composite gel is loaded into the material cylinder of the 3D printer, and 3D printing is performed after the gel cools down.

[0027] Starch gel is used as an edible ink for printing food structures. Specifically, the starch gel is loaded into an extrusion 3D printer and printed using a computer-controlled nozzle. This produces food structures with high precision, self-support, and ideal textures, meeting the functional requirements of the modern food industry for high-strength starch gel.

[0028] The composite gel obtained by the method of this invention exhibits significantly enhanced mechanical properties, strong enough to precisely maintain its shape after injection through the printer nozzle. In contrast, pure starch gel produces coarse lines after printing. This effect is likely due to the relatively weak nature of pure starch gel, resulting in poor recovery of its mechanical properties after shearing. The 3D printed structures produced by the composite gel exhibit better shape fidelity, sharper lines, and greater smoothness.

[0029] To better illustrate the technical means and product effects of the present invention, the preferred embodiments of the present invention will be described below.

[0030] Example 1 A method for preparing a high-strength starch-fatty acid composite gel includes the following steps: (1) After grinding stearic acid and passing it through an 80-mesh sieve, mix it with potato starch in a mixer at a ratio of 2% for 20 min. Place the mixed starch in an extruder and run it at a screw speed of 170 r / min, a cooking zone temperature of 95 ℃, a material moisture content of 35%, and a feeding speed of 15 kg / h. After extrusion, place it in a 45 ℃ oven and dry it for 48 h. Then grind it and pass it through a 100-mesh sieve to obtain the potato starch-stearic acid complex.

[0031] (2) Potato starch-stearic acid complex (3 g, dry basis) and distilled water (25 mL) were mixed and then completely gelatinized through the RVA starch program to obtain starch gel.

[0032] Example 2 A method for preparing a high-strength starch-fatty acid composite gel includes the following steps: (1) After grinding stearic acid and passing it through an 80-mesh sieve, mix it with potato starch in a mixer at a ratio of 2% for 20 min. Place the mixed starch in an extruder and run it at a screw speed of 170 r / min, a cooking zone temperature of 95 ℃, a material moisture content of 45%, and a feeding speed of 15 kg / h. After extrusion, place it in a 45 ℃ oven and dry it for 48 h. Then grind it and pass it through a 100-mesh sieve to obtain the potato starch-stearic acid complex.

[0033] (2) Potato starch-stearic acid complex (3 g, dry basis) and distilled water (25 mL) were mixed and then completely gelatinized through the RVA starch program to obtain starch gel.

[0034] Example 3 A method for preparing a high-strength starch-fatty acid composite gel includes the following steps: (1) After grinding stearic acid and passing it through an 80-mesh sieve, mix it with potato starch in a mixer at a ratio of 2% for 20 min. Place the mixed starch in an extruder and run it at a screw speed of 170 r / min, a cooking zone temperature of 95 ℃, a material moisture content of 55%, and a feeding speed of 15 kg / h. After extrusion, place it in a 45 ℃ oven and dry it for 48 h. Then grind it and pass it through a 100-mesh sieve to obtain the potato starch-stearic acid complex.

[0035] (2) Potato starch-stearic acid complex (3 g, dry basis) and distilled water (25 mL) were mixed and then completely gelatinized through the RVA starch program to obtain starch gel.

[0036] Comparative Example 1 A method for preparing starch gel includes the following steps: Potato starch (3 g, dry basis) and distilled water (25 mL) are mixed and then completely gelatinized using the RVA starch program to obtain starch gel.

[0037] Comparative Example 2 A method for preparing starch gel includes the following steps: (1) Potato starch is placed in an extruder and run at a screw speed of 170 r / min, a cooking zone temperature of 95 ℃, a material moisture content of 45%, and a feeding speed of 15 kg / h. After extrusion, it is placed in a 45 ℃ oven and dried for 48 h. Then, it is ground and passed through a 100-mesh sieve to obtain extruded potato starch.

[0038] (2) After mixing extruded potato starch (3 g, dry basis) and distilled water (25 mL), the mixture is completely gelatinized through the RVA starch program to obtain starch gel.

[0039] The starch gels prepared in Examples 1-3 and Comparative Examples 1-2 were characterized for the following properties: 1. Visual appearance of starch gel Starch gel inverted diagram as shown Figure 1 As shown, the results indicate that all samples with added stearic acid exhibited a stable structure. The native starch showed good flowability, with air bubbles unevenly distributed within the starch's internal network structure.

[0040] 2. Microstructure analysis The microstructure of the samples was analyzed using scanning electron microscopy (SEM). Starch gels were freeze-dried under vacuum for 48 h, and the samples were sliced ​​horizontally and vertically. Appropriately sized samples were mounted on conductive adhesive on a sample rod and coated using an ion sputtering machine. Images were taken at 500x magnification under an accelerating voltage of 3.0 kV.

[0041] from Figure 2 It can be seen that potato starch gelatinization better preserves the integrity of the granules. The swollen starch granules with good integrity change shape during interaction, filling the matrix volume and forming a strong gel network. The addition of stearic acid leads to the formation of numerous aggregates, resulting in a porous honeycomb structure. With increasing moisture content, the gel honeycomb network structure becomes more uniform.

[0042] 3. Crystal structure analysis from Figure 2 X-ray diffraction was used to analyze the crystal structure of the sample. The sample was evenly spread in the sample cell, and the crystal structure was determined using an X-ray diffractometer. The diffraction angle 2θ scanning range was 4°–40°, the scanning speed was 4° / min, the step size was 0.02°, and the accelerating voltage and current were 40 kV and 40 mA, respectively.

[0043] from Figure 3 It can be seen that after adding stearic acid, the crystal type changed from type B to type B+V, indicating the formation of an endogenous branched starch-lipid V-type structure. Furthermore, the peak intensity of the V-type crystals increased with increasing moisture content, indicating that the intermolecular interactions between the complexes strengthened with increasing moisture content. This increased binding between potato starch and stearic acid may be due to water increasing the steric hindrance of fatty acids, thus increasing the diameter of the V-type amylose helical cavity and reducing the interlayer spacing of the V-type crystals in the complex.

[0044] 4. Application of the gel obtained in the examples in 3D printing.

[0045] The starch gels prepared in the examples and comparative examples were used as edible inks, loaded into the syringe of an extrusion 3D printer, and printed after removing air bubbles. The shape retention, texture quality, and textural properties of the printed structures were evaluated.

[0046] The results are as follows Figure 4As shown. All starch-based gels were extruded smoothly, likely because they are shear-thinning materials with good texture recovery after shearing. Furthermore, the composite gels exhibited mechanical properties strong enough to precisely maintain their shape after injection through the printer nozzle. In contrast, pure starch gels produced coarse lines after printing, likely due to their relatively weaker structure and poorer mechanical recovery after shearing. The 3D printed structures produced by the composite gels showed better shape fidelity, sharper lines, and greater smoothness. Visual observation of different samples indicated that the samples with a material moisture content of 55% exhibited the best printability and good self-supporting ability.

[0047] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

[0048] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for preparing a high-strength starch-fatty acid composite gel, characterized in that, include: Step 1: Mix starch and fatty acids to obtain mixed starch. Extrude the mixed starch through a twin-screw extruder, dry, grind, and sieve to obtain potato starch-stearic acid complex. Step 2: The potato starch-stearic acid complex is heated through the RVA starch program to completely gelatinize it and obtain starch gel.

2. The method for preparing the high-strength starch-fatty acid composite gel according to claim 1, characterized in that, The mass ratio of the fatty acid to starch is 1~3:

100.

3. The method for preparing the high-strength starch-fatty acid composite gel according to claim 1, characterized in that, The fatty acid mentioned in step 1 is in powder form with a particle size of 80 mesh.

4. The method for preparing the high-strength starch-fatty acid composite gel according to claim 1, characterized in that, The screw speed of the twin-screw extruder is 110~240 rpm, and the temperature of the cooking zone of the twin-screw extruder is 75~110 ℃.

5. The method for preparing the high-strength starch-fatty acid composite gel according to claim 1, characterized in that, The process parameters for drying and grinding in step 1 are as follows: drying in an oven at 45 ℃ for 48 h, then grinding with a grinding mill and passing through a 100-mesh sieve.

6. The method for preparing the high-strength starch-fatty acid composite gel according to claim 1, characterized in that, The fatty acids include stearic acid, palmitic acid and / or lauric acid; the starch is sweet potato starch, potato starch and / or tapioca starch.

7. The method for preparing the high-strength starch-fatty acid composite gel according to claim 1, characterized in that, The potato starch-stearic acid complex described in step 2 is heated using the RVA starch program, wherein 3.0 g of starch and 25 mL of distilled water are placed in an aluminum can and the RVA starch program is run.

8. The high-strength starch-fatty acid composite gel prepared by the preparation method according to claims 1-7.

9. The application of the high-strength starch-fatty acid composite gel according to claim 8, characterized in that, Used to prepare edible ink for printing food structures.

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