Soy protein amyloid fibril with adjustable morphology and method for preparing same

Abstract

The application discloses a method for preparing soy protein amyloid fibrils with adjustable morphology structure, and belongs to the field of food. The method comprises the following steps: (1) preparation of a soy protein solution and protonation control; (2) formation of soy protein amyloid fibrils. First, soy protein is dispersed in deionized water, and after stirring and centrifugal treatment, a soy protein solution is obtained, and the pH of the soy protein solution is adjusted to 1.0, 2.0 and 3.0 by using hydrochloric acid; then, heating and stirring are carried out at 85 DEG C and 200-300 rpm for 24 h, the soy protein is induced to form amyloid fibrils, and samples are taken at 3 h, 9 h, 12 h and 24 h. By adjusting the protonation conditions of the soy protein, the aggregation process of the soy protein amyloid fibrils is changed, the obtained soy protein amyloid fibrils have different fiber lengths, fiber heights, pitches and short fiber and long fiber morphology characteristics, so that the morphology structure of the soy protein amyloid fibrils can be controlled. The preparation method is simple, the soy protein amyloid fibrils with different morphology structures can be obtained by changing the protonation conditions, and the application provides a technical basis for the structure control of the soy protein amyloid fibrils and the application of the soy protein amyloid fibrils in the field of food.

Description

Technical Field

[0001] This invention belongs to the food field, specifically relating to a soybean protein starch-like fiber with adjustable morphology and a method for its preparation. Background Technology

[0002] Soy protein is a widely available plant protein with high nutritional value. It possesses excellent gelling, emulsifying, foaming, and water-holding properties, making it a promising candidate for food processing and plant protein product development. With the deepening research into the functional utilization of plant proteins, the structural regulation and self-assembly behavior of soybean protein have received increasing attention.

[0003] Under certain acidic and heating conditions, soybean protein can partially unfold and reassemble through intermolecular interactions to form soybean protein amyloid fibers with a specific ordered structure. Compared with unfibrinated soybean protein, soybean protein amyloid fibers have different molecular assembly states and microstructures, and have potential application value in food colloids, gel systems, and plant protein functional materials.

[0004] The formation of soybean amyloid fibers is a continuous process involving protein unfolding, aggregation, nucleation, and fiber growth. The final fiber structure is influenced by intermolecular interactions between proteins and external environmental conditions. Specifically, solution pH can alter the protonation state, charge distribution, and intermolecular interactions of protein molecules, thereby affecting protein aggregation behavior and the fibrosis process.

[0005] Currently, research on soybean amyloid fibers mainly focuses on the fiber formation mechanism and its structural characterization. However, there is still room for further research into methods for regulating the morphology and structure of soybean amyloid fibers under different protonation conditions. In particular, under different pH conditions, the morphological characteristics of fibers during formation, such as length, height, pitch, and the presence of short and long fibers, vary. Therefore, it is necessary to establish a method for regulating the morphology and structure of soybean amyloid fibers by adjusting protonation conditions to obtain soybean amyloid fibers with different morphological characteristics, providing a technical basis for their structural design and application in the food industry. Summary of the Invention

[0006] The purpose of this invention is to provide soybean protein amyloid fibers with adjustable morphology and a method for preparing the same. By changing the protonation conditions of the soybean protein solution, the aggregation behavior during the formation of soybean protein amyloid fibers is regulated, thereby obtaining soybean protein amyloid fibers with different morphological structures.

[0007] The technical problem to be solved by the present invention is achieved through the following technical solution:

[0008] A method for preparing soybean protein amyloid fibers with adjustable morphology, characterized by the following steps:

[0009] Step 1: Preparation and protonation control of soybean protein solution: Soybean protein was dispersed in deionized water, stirred thoroughly, and centrifuged. The supernatant was collected to obtain the soybean protein solution. The pH of the soybean protein solution was adjusted to 1.0, 2.0 and 3.0 using hydrochloric acid solution to obtain soybean protein solutions under different protonation conditions.

[0010] Step 2: Formation of soybean protein amyloid fibers: Soybean protein solutions under different pH conditions were placed at 85 ℃ and stirred continuously at 200-300 rpm for 24 h to induce the formation of soybean protein amyloid fibers. Sampling times were 3, 9, 12 and 24 h, respectively. The aggregation process of soybean protein amyloid fibers was regulated by different protonation conditions, so that the obtained soybean protein amyloid fibers had different fiber lengths, fiber heights, pitches and short and long fiber morphological characteristics, thereby obtaining soybean protein amyloid fibers with adjustable morphological structures.

[0011] According to claim 1, a soybean protein amyloid fiber with adjustable morphology and structure and a method for preparing the same are characterized in that, in step one, the soybean protein is soybean protein isolate, and the soybean protein is mixed with deionized water to form a protein solution.

[0012] According to claim 1, a soybean protein starch-like fiber with adjustable morphology and a method for preparing the same are characterized in that the hydrochloric acid in step one is a 6 M hydrochloric acid solution, and the pH of the soybean protein solution is adjusted to 1.0, 2.0 or 3.0 by hydrochloric acid to obtain soybean protein solutions with different protonation degrees.

[0013] According to claim 1, a soybean protein starch-like fiber with adjustable morphology and structure and a method for preparing the same, characterized in that, in step two, the heating temperature is 85 ℃, the stirring speed is 200-300 rpm, and the heating induction time is 24 h.

[0014] According to claim 1, a soybean protein amyloid fiber with adjustable morphology and a method for preparing the same, characterized in that the sampling times during the formation of the soybean protein amyloid fiber in step two are 3, 9, 12 and 24 h, respectively.

[0015] According to claim 1, a soybean protein amyloid fiber with adjustable morphology and a method for preparing the same are characterized in that the soybean protein amyloid fiber is characterized by morphology using atomic force microscopy, and the fiber length, fiber height and pitch are analyzed based on the fiber morphology to characterize the differences in morphological structure of soybean protein amyloid fiber under different protonation conditions.

[0016] This invention obtains soybean protein amyloid fibers with different morphologies under the same heating induction conditions by adjusting the protonation conditions of soybean protein solutions. By changing the pH conditions, the aggregation behavior during the formation of soybean protein amyloid fibers can be modulated, resulting in differences in the length, height, pitch, and morphology of short and long fibers, thus achieving controllable morphology of soybean protein amyloid fibers. The preparation method of this invention is simple to operate, with clearly defined process conditions, and does not require the introduction of complex synthetic additives, providing a technical foundation for the structural design, controllable preparation, and application of soybean protein amyloid fibers in the food industry. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the present invention;

[0018] Figure 2 This is an atomic force microscope image showing the morphology and fiber height distribution.

[0019] Figure 3 This is an analysis graph showing the autocorrelation function of the fiber twist angle as a function of the inner contour length.

[0020] Figure 4 This is an analysis graph showing the change of fiber height autocorrelation function with inner contour length. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments. Any equivalent substitutions or simple changes made based on the technical solution of the present invention should be included within the scope of protection of the present invention.

[0022] A method for preparing soybean protein amyloid fibers with adjustable morphology, characterized in that the method comprises the following steps:

[0023] Step 1: Preparation and protonation control of soybean protein solution: Soybean protein was dispersed in deionized water, stirred thoroughly, and centrifuged. The supernatant was collected to obtain the soybean protein solution. The pH of the soybean protein solution was adjusted to 1.0, 2.0 and 3.0 using hydrochloric acid solution to obtain soybean protein solutions under different protonation conditions.

[0024] Step 2: Formation of soybean protein amyloid fibers: Soybean protein solutions under different pH conditions were placed at 85 ℃ and stirred continuously at 200-300 rpm for 24 h to induce the formation of soybean protein amyloid fibers. Sampling times were 3, 9, 12 and 24 h, respectively. The aggregation process of soybean protein amyloid fibers was regulated by different protonation conditions, so that the obtained soybean protein amyloid fibers had different fiber lengths, fiber heights, pitches and short and long fiber morphological characteristics, thereby obtaining soybean protein amyloid fibers with adjustable morphological structures.

[0025] Example 1:

[0026] Soy protein was dispersed in deionized water, and after stirring and centrifugation, the supernatant was collected. The pH of the soybean protein solution was adjusted to 1.0 using hydrochloric acid. The pH-adjusted soybean protein solution was heated and stirred at 85 °C for 24 h at a stirring speed of 200–300 rpm. Samples were taken at 3, 9, 12, and 24 h during fiber formation to obtain soybean protein starch-like fibers under pH 1.0 conditions.

[0027] Example 2:

[0028] Soy protein was dispersed in deionized water, and after stirring and centrifugation, the supernatant was collected. The pH of the soybean protein solution was adjusted to 2.0 using hydrochloric acid. The pH-adjusted soybean protein solution was heated and stirred at 85 °C for 24 h at a stirring speed of 200–300 rpm. Samples were taken at 3, 9, 12, and 24 h during fiber formation to obtain soybean protein starch-like fibers under pH 2.0 conditions.

[0029] Example 3:

[0030] Soy protein was dispersed in deionized water, and after stirring and centrifugation, the supernatant was collected. The pH of the soybean protein solution was adjusted to 3.0 using hydrochloric acid. The pH-adjusted soybean protein solution was heated and stirred at 85 °C for 24 h at a stirring speed of 200–300 rpm. Samples were taken at 3, 9, 12, and 24 h during fiber formation to obtain soybean protein starch-like fibers under pH 3.0 conditions.

[0031] Comparative analysis of the above embodiments revealed that different protonation conditions significantly affected the morphology and structure of soybean amyloid fibers. Short and long fibers formed under pH 2 conditions exhibited higher fiber heights, with longer fibers showing more pronounced morphology and a more complete fiber network structure. Autocorrelation analysis of torsion angle and height showed that the torsion and height of the fibers exhibited different variation characteristics along the inner contour length direction under different pH conditions. This indicates that adjusting the protonation conditions can alter the aggregation morphology and structural characteristics of soybean amyloid fibers, with pH 2 conditions favoring the formation of soybean amyloid fibers with higher heights and more pronounced long fiber structures.

Claims

1. A soybean protein starch-like fiber with adjustable morphology and structure, and a method for preparing the same, characterized in that... The method steps are as follows: Step 1: Preparation and protonation control of soybean protein solution: Disperse soybean protein in deionized water, stir thoroughly, centrifuge, and take the supernatant to obtain soybean protein solution; The pH of the soybean protein solution was adjusted to 1.0, 2.0 and 3.0 respectively using hydrochloric acid solution to obtain soybean protein solutions under different protonation conditions; Step 2: Formation of soybean protein amyloid fibers: Soybean protein solutions under different pH conditions were placed at 85 ℃ and stirred continuously at 200-300 rpm for 24 h to induce the formation of soybean protein amyloid fibers. Sampling times were 3, 9, 12 and 24 h, respectively. The aggregation process of soybean protein amyloid fibers was regulated by different protonation conditions, so that the obtained soybean protein amyloid fibers had different fiber lengths, fiber heights, pitches and short and long fiber morphological characteristics, thereby obtaining soybean protein amyloid fibers with adjustable morphological structures.

2. The soybean protein starch-like fiber with adjustable morphology and structure according to claim 1, and the method for preparing the same, characterized in that, The soy protein mentioned in step one is soy protein isolate, which is mixed with deionized water to form a protein solution.

3. The soybean protein starch-like fiber with adjustable morphology and structure according to claim 1, and the method for preparing the same, characterized in that... The hydrochloric acid mentioned in step one is a 6 M hydrochloric acid solution. The pH of the soybean protein solution is adjusted to 1.0, 2.0 or 3.0 by hydrochloric acid to obtain soybean protein solutions with different protonation levels.

4. The soybean protein starch-like fiber with adjustable morphology and structure according to claim 1, and the method for preparing the same, characterized in that, The heating temperature in step two is 85 ℃, the stirring speed is 200-300 rpm, and the heating induction time is 24 h.

5. The soybean protein starch-like fiber with adjustable morphology and structure according to claim 1, and the method for preparing the same, characterized in that, The sampling times during the formation of soybean protein amyloid fibers in step two were 3, 9, 12, and 24 hours, respectively.

6. The soybean protein starch-like fiber with adjustable morphology and structure according to claim 1, and the method for preparing the same, characterized in that, The soybean protein amyloid fibers were characterized by atomic force microscopy, and the fiber length, fiber height and pitch were analyzed based on the fiber morphology to characterize the differences in morphological structure of soybean protein amyloid fibers under different protonation conditions.

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