Use of nanocrystallized thin-walled cell walls as low-GI food modifiers, low-GI food modifiers, methods of making same and starch-like systems comprising same

Abstract

The present invention provides the use of a nanocrystallized thin-walled cell wall as a low-GI food modifier wherein the nanocrystallized thin-walled cell wall is edible wherein cellulose has a crystallinity of 80% to 95%, has one-dimensional characteristics, a lateral dimension of 100 nm or less, a longitudinal dimension of 1 [mu] m or more, and a thickness of 1 [mu] m or more. The dispersion liquid in water has a viscosity of 200 Pas or more at a nanocrystallized thin-walled cell wall mass concentration of 0.5% and remains stable in a temperature range of 5 to 40 DEG C. The invention also provides a low-GI food improver, a preparation method thereof and a starch-like system containing the low-GI food improver.

Description

Technical Field

[0001] This invention relates to the field of food processing, and more specifically, to the use of a nano-sized thin-walled cell wall as a low-GI food modifier, a low-GI food modifier, its preparation method, and a starch-like system comprising the same. Background Technology

[0002] Cellulose, as the most widely distributed and abundant natural polymer in nature, accounts for more than 50% of the carbon content in the plant kingdom and is the main structural component of plant cell walls. As a renewable carbon source, it shows broad application prospects in the fields of energy, materials, and chemical engineering.

[0003] The food industry is another application area for cellulose. Edible cellulose is a typical example of insoluble dietary fiber, which cannot be digested by humans and plays a very important role in promoting intestinal peristalsis and defecation. Because it does not provide energy but increases satiety, it is widely used as an additive in weight-loss meals.

[0004] Beyond its basic physiological functions, the understanding of dietary fiber's role in blood sugar control is constantly deepening. Previously, it was recognized that dietary fiber's benefits to blood sugar primarily manifest in slowing sugar absorption, reducing blood sugar fluctuations, and improving insulin sensitivity. It helps maintain stable blood sugar levels by slowing digestion and regulating intestinal function, which is particularly beneficial for people with diabetes or high blood sugar. When it comes into contact with water, it forms a viscous gel-like substance that coats carbohydrates in food, slowing their breakdown and absorption in the intestines. Simultaneously, long-term adequate intake of dietary fiber can improve cellular sensitivity to insulin. Studies have shown that increasing dietary fiber intake can effectively reduce the risk of type 2 diabetes. Fiber promotes the production of short-chain fatty acids (such as butyrate) by regulating the balance of intestinal flora. These substances can directly act on pancreatic β-cells, enhancing insulin secretion function. Therefore, based on the above understanding, dietary fiber has been proposed as a food additive to assist in blood sugar control. For example, Chinese patent application CN202510726682.2 discloses noodles with blood sugar control function and their preparation method, in which dietary fiber is added to flour-based foods as an auxiliary blood sugar regulator.

[0005] Nanocellulose refers to cellulose materials with a scale in the nanometer range. Compared to ordinary cellulose, nanocellulose possesses more unique properties, such as high specific surface area and high hydrophilicity, and has the potential to achieve more unique functions. Several nano-sized dietary fibers have been developed to provide further functionalities. For example, Chinese patent application 202411037355.8 discloses a nano-sized burdock functional dietary fiber and its preparation method, which provides starch digestion inhibition and hypoglycemic activity. This method uses ultrasonic synergistic complex enzyme treatment to effectively decompose the insoluble dietary fiber in burdock, altering the spatial structure of the insoluble dietary fiber to prepare nano-sized burdock functional dietary fiber with a particle size of 200 nm to 600 nm. This fiber can inhibit the activity of amylase and glucosidase, achieving a hypoglycemic effect.

[0006] Current mechanisms for controlling blood sugar using dietary fiber mainly include: (i) replacing starch to provide a feeling of fullness and reduce starch intake; (ii) forming a gel after absorbing water to physically encapsulate starch and slow down its digestion and absorption; (iii) indirectly increasing insulin sensitivity; and (iv) nanostructuring the natural dietary fiber of certain special plants by decomposing and modifying its spatial structure to inhibit the activity of digestive enzymes and reduce starch digestion. However, the inventors of this invention have found that these mechanisms also have corresponding drawbacks. Mechanism (i) requires a large amount of dietary fiber to replace the volume of starch, which alters the taste of food and affects people's appetite. Mechanism (ii) may require the simultaneous intake of a large amount of water, which may lead to increased gastric burden and indigestion. Mechanism (iii) relies on long-term regulation of the endocrine system and is not effective in lowering blood sugar for a single large intake of starch. Mechanism (iv) requires enzymatic hydrolysis of cellulose and artificial spatial reconstruction or modification, which is a complex process and has special requirements for plant sources.

[0007] In particular, for mechanism iv), the enzymatic hydrolysis method is complex, requires stringent conditions, and has high enzyme reagent costs, making it difficult to achieve large-scale production of nanofibers and limiting its practicality. Although other methods besides enzymatic hydrolysis can be used to prepare nano-cellulose, existing nano-cellulose preparation technologies generally employ strong acids and strong oxidants, which are harmful to human health, posing environmental pollution risks and making it difficult to produce nano-sized dietary fibers suitable for the food industry. To address environmental concerns, Chinese patent application CN202110607105.3 discloses an environmentally friendly method for preparing nano-cellulose and recovering the chemical solution. This application proposes an environmentally friendly preparation method to address the scarcity of nanocellulose varieties. It suggests starting with plant-based raw materials, primarily wood, and using a 1:2 to 2:1 volume ratio mixture of 17.5 mol / L glacial acetic acid and 30 wt% hydrogen peroxide as the treatment solution. The raw materials are then soaked, followed by pulverization, homogenization, microfluidization, and grinding to obtain nanocellulose. This nanocellulose can be used in biodegradable plastic reinforcing agents, rheology modifiers, thickeners, and other fields. Anhydrous copper sulfate is used to further recycle the treatment solution. However, this application does not disclose the morphology of the obtained nanocellulose, nor does it mention the ability to obtain food-grade nanocellulose or its application in the food industry.

[0008] Therefore, there is still a need to develop cellulose-based food modifiers that can be used in the food industry to control blood sugar. Summary of the Invention

[0009] The purpose of this invention is to develop the use of cellulose materials as low-GI food modifiers, low-GI food modifiers, their preparation methods, and starch-like systems containing them.

[0010] In one aspect, the present invention provides the use of nano-sized thin-walled cell walls as a low-GI food modifier, wherein,

[0011] The nano-sized thin-walled cell walls are edible;

[0012] The cellulose in the nano-thin-walled cell wall has a crystallinity of 80% to 95%.

[0013] The nano-thin-walled cell wall has one-dimensional characteristics, with a lateral dimension of less than 100 nm and a longitudinal dimension of more than 1 μm;

[0014] The dispersion of the nano-thin-walled cell wall in water has a viscosity of more than 200 Pa•s when the mass concentration of the nano-thin-walled cell wall is 0.5%, and remains stable in a temperature range of 5 to 40°C.

[0015] Optionally, the low-GI food improver is a low-GI food improver for starch-like systems.

[0016] Optionally, the starch-like system is a rice flour or wheat flour product, preferably rice noodles, noodles, or biscuits.

[0017] Optionally, the cell source of the nano-sized thin-walled cell wall is selected from herbaceous plants, preferably from rapeseed straw, bamboo, and seaweed.

[0018] In another aspect, the present invention provides a low-GI food modifier, wherein,

[0019] The low-GI food modifier contains nano-sized thin-walled cell walls.

[0020] The nano-sized thin-walled cell walls are edible;

[0021] The cellulose in the nano-thin-walled cell wall has a crystallinity of 80% to 95%.

[0022] The nano-thin-walled cell wall has one-dimensional characteristics, with a lateral dimension of less than 100 nm and a longitudinal dimension of more than 1 μm;

[0023] The dispersion of the nano-thin-walled cell wall in water has a viscosity of more than 200 Pa•s when the mass concentration of the nano-thin-walled cell wall is 0.5%, and remains stable in a temperature range of 5 to 40°C.

[0024] Optionally, the low-GI food improver is a dispersion of the nano-sized thin-walled cell wall in water at a mass concentration of 0.1% to 3%, preferably 0.3% to 2.5%, more preferably 0.5% to 2%.

[0025] In another aspect, the present invention provides a method for preparing the aforementioned low-GI food modifier, the method comprising preparing the nano-sized thin-walled cell wall by the following steps:

[0026] A) Add natural plant cell sources to food-grade anhydrous ethanol, heat to 60 to 80°C, and react for 24 to 48 hours;

[0027] B) Add the mixture obtained in step A) to a solution of food-grade hydrogen peroxide and food-grade glacial acetic acid, and react at 60 to 80°C for 24 to 48 h to obtain bleached thin-walled cell walls.

[0028] C) The bleached thin-walled cell wall obtained in step B) is pulverized using a post-treatment including high-pressure homogenization to obtain the nano-thin-walled cell wall.

[0029] In another aspect, the present invention provides a starch-like system comprising the aforementioned low-GI food modifier, wherein the low-GI food modifier is a dispersion of the nano-sized thin-walled cell wall in water at a mass concentration of 0.1% to 3%, preferably 0.3% to 2.5%, more preferably 0.5% to 2%, and the mass ratio of the low-GI food modifier to the starch-like substance in the starch-like system is in the range of 20:1 to 10:1.

[0030] Optionally, the starch-like system is a rice flour or wheat flour product, preferably rice noodles, noodles, or biscuits.

[0031] Optionally, the total mass content of dietary fiber is 0.5% to 1.5%.

[0032] The advantages of the uses discovered in this invention are at least as follows: using unmodified and edible nano-sized thin-walled cell walls derived from natural plants as low-GI food modifiers; exhibiting good mechanical, chemical, hygroscopic, biodegradable, and thermal stability due to their high crystallinity of cellulose, facilitating storage and transportation; exhibiting good activity due to their unique morphology; facilitating food processing due to the high viscosity and high stability of their dispersion in water; and demonstrating a high low-GI effect in practical applications. The low-GI food modifiers discovered in this invention have corresponding advantages.

[0033] The advantages of the method for preparing low-GI food modifiers discovered in this invention are at least that it can prepare the required nano-sized thin-walled cell walls simply, efficiently, with low energy consumption and no pollution, and is particularly suitable for herbal plant sources.

[0034] The advantages of the starch-like system discovered in this invention are at least as follows: it has excellent low-GI properties, is made of natural ingredients, is easy to process, and provides a good taste. Attached Figure Description

[0035] Figure 1 A photo of untreated rapeseed straw.

[0036] Figure 2 Photographs show different stages of the preparation of nano-sized thin-walled cell walls from rapeseed straw.

[0037] Figure 3 A scanning electron microscope image of rapeseed straw raw material is shown.

[0038] Figure 4 This image shows a scanning electron microscope image of rapeseed straw raw material after image processing.

[0039] Figure 5 The electron micrographs show the gradually changing microscopic appearance of rapeseed straw during bleaching treatment using the method of the present invention.

[0040] Figure 6 The diagram shows the proportions of the three components (cellulose, hemicellulose, and lignin) in the inner core, outer shell, and whole of rapeseed straw raw material, as well as the changes in their proportions after bleaching and crushing.

[0041] Figure 7 The X-ray diffraction curves of the obtained nano-thin-walled cell wall sample are shown.

[0042] Figure 8 This image shows a nano-sized thin-walled cell wall with one-dimensional features as observed under an electron microscope.

[0043] Figure 9 The relationship between viscosity and shear rate of the nano-sized thin-walled cell wall dispersion obtained in the examples is shown.

[0044] Figure 10 The data curves showing the relationship between the storage modulus / loss modulus and frequency of the nano-thin-walled cell wall dispersion obtained in the examples are shown.

[0045] Figure 11 The images show starch without low-GI food improvers and starch with low-GI food improvers.

[0046] Figure 12 Rheological data curves are shown for a mixture system in which low-GI food modifiers with nano-thin-walled cell wall concentrations of 0.5%, 1%, and 1.5% were added to starch, and for a mixture system in which cellulose nanocrystals obtained by strong acid hydrolysis were added, showing the relationship between viscosity and shear rate.

[0047] Figure 13 The data curves showing the relationship between storage modulus / loss modulus and frequency are presented for a mixed system in which low-GI food modifiers with nano-thin-walled cell wall mass concentrations of 0.5%, 1%, and 1.5% were added to starch, and for a mixed system in which cellulose nanocrystals obtained by strong acid hydrolysis were added.

[0048] Figure 14 Rapid viscosity analysis data curves are shown for a mixture obtained by adding a low-GI food modifier, in which a 1% mass concentration of nano-thin-walled cell walls is added to starch, and for a mixture without the additive.

[0049] Figure 15 The DSC data curves of the mixtures obtained by adding low-GI food modifiers with nano-thin-walled cell wall concentrations of 0.5%, 1%, and 1.5% to starch, respectively, and the mixture without additives are shown.

[0050] Figure 16The UV spectra of the mixtures obtained by adding low-GI food modifiers with nano-thin-walled cell wall concentrations of 0.5%, 1%, and 1.5% to amylase, respectively, and the mixture without additives are shown.

[0051] Figure 17 Fluorescence spectra of mixed systems and systems without additives are shown, in which low-GI food modifiers with nano-thin-walled cell wall concentrations of 0.5%, 1%, and 1.5% are added to amylase.

[0052] Figure 18 Data on porcine pancreatic amylase activity are shown in a mixture obtained by adding low-GI food modifiers with nano-thin-walled cell wall concentrations of 0.5%, 1%, and 1.5% to amylase, and in a mixture obtained by adding cellulose nanocrystals obtained by strong acid hydrolysis.

[0053] Figure 19 The figures show the contents of rapidly digestible starch, slowly digestible starch, and resistant starch in a mixture system in which low-GI food modifiers with nano-thin-walled cell wall concentrations of 0.5%, 1%, and 1.5% were added to starch, and in a mixture system in which cellulose nanocrystals obtained by strong acid hydrolysis were added.

[0054] Figure 20 Scanning electron microscope images of starch gelatinized with and without low-GI food modifiers are shown.

[0055] Figure 21 The Fourier transform infrared spectra of starch gelatinized with low-GI food modifiers containing nano-thin-walled cell walls at concentrations of 0%, 0.5%, 1%, and 1.5% are shown.

[0056] Figure 22 The X-ray diffraction curves of starch gelatinized with low-GI food modifiers containing nano-thin-walled cell walls at concentrations of 0%, 0.5%, 1%, and 1.5% are shown.

[0057] Figure 23 The experiment showed the cytotoxicity of the low-GI food modifier with L929 cells, colonic epithelial cells, and gastric epithelial cells. Detailed Implementation

[0058] In response to the technical problems existing in related technologies, the inventors of this invention have developed the use of nano-sized thin-walled cell walls with specific morphology and properties as low-GI food modifiers.

[0059] For diabetic patients, a core issue in blood sugar control is how to rationally manage the glycemic index (GI) through meals. When attempting to modify food by adding dietary fiber, ideally, the fiber should remain in its natural state so that it can effectively control the GI curve after meals without burdening the digestive system or negatively impacting the taste of the food. Furthermore, as a food improver, it should possess good storage stability, high activity during use, and be easy to apply during food processing.

[0060] The inventors of this invention, through research, discovered the use of a processed thin-walled cell wall as a low-GI food modifier for dietary fiber. This thin-walled cell wall is nano-sized but retains some of its natural structure, providing better low-GI functionality on top of conventional dietary fiber without burdening the digestive system, and offering the same or better taste. This low-GI food modifier combines good storage stability and high activity during use, and is easy to apply in food processing.

[0061] Parenchyma cells are one of the basic building blocks of plants and can further specialize into sclerenchyma cells, vascular tissue cells, and epidermal cells during subsequent growth. Parenchyma cells are essentially composed of a cell wall and the cytoplasm contained within it. The cell wall primarily contains cellulose, hemicellulose, and lignin, and also contains inorganic matter (ash) and other extracts. Compared to the cell walls of woody products such as timber, the parenchyma cell walls of unprocessed herbaceous plants have a higher content of silica (inorganic matter) and a higher content of waxes in their extracts.

[0062] In this invention, the term "nanosized thin-walled cell wall" refers to a thin-walled cell wall that has been nanosized, with at least one dimension having a scale in the nanoscale range, while retaining at least part of the natural structure of the thin-walled cell wall.

[0063] The term "low-GI food improver" refers to a class of functional food additives that significantly reduce the glycemic index (GI) of food by adjusting its physical structure, chemical composition, or digestible properties. Their core objective is to promote a gradual rise in postprandial blood glucose levels.

[0064] The terms "rapidly digestible starch," "slowly digestible starch," and "resistant starch" generally refer to the classification of starches into three categories based on their digestion speed and absorbability in the small intestine: rapidly digestible starch is quickly broken down and absorbed by the small intestine, leading to a rapid rise in blood sugar (such as white bread and cooked potatoes); slowly digestible starch is completely digested but at a slower rate, providing sustained energy and resulting in a stable rise in blood sugar (such as whole wheat bread and oats); and resistant starch is not digested and absorbed by the small intestine at all, but directly enters the large intestine where it is fermented by gut microbiota, does not raise blood sugar, has prebiotic effects, and can improve gut health and metabolism (such as cold rice, raw bananas, and beans).

[0065] The inventors of this invention have discovered that, compared with existing cellulose-based dietary fibers in related technologies, the nano-sized thin-walled cell wall proposed in this invention, as a low-GI food modifier, can not only provide the same or better blood sugar control effects, but also provide other beneficial effects and reduce side effects.

[0066] In one embodiment, the present invention provides the use of nano-sized thin-walled cell walls as a low-GI food modifier, wherein,

[0067] The nano-sized thin-walled cell walls are edible;

[0068] The cellulose in the nano-thin-walled cell wall has a crystallinity of 80% to 95%.

[0069] The nano-thin-walled cell wall has one-dimensional characteristics, with a lateral dimension of less than 100 nm and a longitudinal dimension of more than 1 μm;

[0070] The dispersion of the nano-thin-walled cell wall in water has a viscosity of more than 200 Pa•s when the mass concentration of the nano-thin-walled cell wall is 0.5%, and remains stable in a temperature range of 5 to 40°C.

[0071] This invention selects a special nano-sized thin-walled cell wall for use as a low-GI food modifier.

[0072] The main component of thin-walled cell walls is cellulose, and it also contains hemicellulose and lignin. Correspondingly, nano-sized thin-walled cell walls are also a type of cellulose product. Compared with other types of cellulose products, one characteristic of the nano-sized thin-walled cell walls of this invention is that they consist of thin-walled cell walls derived from natural plants, rather than artificially synthesized or modified products. They are nano-fragments of thin-walled cell walls with most of the lignin and some hemicellulose removed, retaining some of the microstructural characteristics of natural plant thin-walled cell walls, such as their thickness range and the arrangement of cellulose fibers, without reorganization or modification of the fibers. A second characteristic of the nano-sized thin-walled cell walls of this invention is that they are edible and can be prepared from low-cost natural plant sources using simple, pollution-free methods, thus allowing for economical and safe use as a food improver. A third characteristic of the nano-sized thin-walled cell walls of this invention is their high crystallinity, which gives them high mechanical stability, chemical stability, biodegradability, and thermal stability, as well as low hygroscopicity in air, resulting in high long-term storage stability, which is beneficial for storage, transportation, and use as an independent low-GI improver. The fourth characteristic of the nano-thin-walled cell wall of this invention is its one-dimensional nature and high aspect ratio, which allows it to exhibit good activity and performance during use, and facilitates gel formation with low water content. The fifth characteristic of the nano-thin-walled cell wall of this invention is that it retains high viscosity even when dispersed in water at low doses, thus improving the texture and mouthfeel of food. The sixth characteristic of the nano-thin-walled cell wall of this invention is its good thermal stability after dispersion, which is beneficial for practical applications in food processing. The seventh characteristic of the nano-thin-walled cell wall of this invention is its enhanced ability to convert rapidly digestible starch and slowly digestible starch into resistant starch, providing better low-GI performance.

[0073] Practical low-GI food modifiers need to meet a variety of requirements in order to provide more benefits or reduce adverse effects on the resulting food and food preparation process while fully utilizing the glycemic control mechanism, achieving a balance among various desired properties.

[0074] Cellulose includes natural cellulose and artificially reconstituted / modified cellulose. For example, the nano-sized burdock functional dietary fiber mentioned earlier belongs to the latter. It involves the enzymatic decomposition of insoluble dietary fiber in burdock, altering its spatial structure. Artificially reconstituted / modified fibers can achieve specific functions. However, in the food industry, consumers generally prefer purely natural products or products that are not heavily processed and are close to their natural state, even at the cost of some functionality. Therefore, reconstituted or modified non-natural dietary fibers often fail to meet consumer demands. The nano-sized thin-walled cell wall of this invention does not decompose, alter, reconstitute, or modify the fibers in the natural cell wall. It retains at least part of the microstructure of the natural plant thin-walled cell wall, more closely resembling the natural state of the raw material, while providing sufficient sugar control functionality, thus meeting consumer demand for natural or near-natural products.

[0075] This invention not only preserves the natural properties of thin-walled cell walls but also nanoscales them without introducing toxic or harmful substances, ensuring the edibility of the nanoscaled thin-walled cell walls. The nanoscaled thin-walled cell walls of this invention can be prepared from low-value plant raw materials using a process that is environmentally friendly, energy-efficient, and simple, offering significant cost advantages.

[0076] In addition to its low-GI functionality, a low-GI food modifier should possess high stability before being added to a food system, and should not easily deteriorate or become ineffective due to environmental factors such as stress during transportation, moisture absorption from the air, or heat during storage. This invention selects a low-GI food modifier with highly crystalline, nano-sized thin-walled cell walls, and its product exhibits long-term shelf stability.

[0077] However, high crystallinity can lead to a potential decrease in activity during use. This invention addresses this issue by using nano-sized thin-walled cell walls with one-dimensional characteristics, a high aspect ratio, and a lateral dimension below 100 nm. Compared to other granular products, this type of nano-sized thin-walled cell wall, when added to a solvent such as water, exhibits a high specific surface area due to its high aspect ratio, allowing it to rapidly bind with water and fully activate, quickly exerting its blood sugar control mechanism. Therefore, its blood sugar control effect is not reduced by high crystallinity. The high aspect ratio also makes its one-dimensional fiber characteristics more pronounced, potentially leading to curling or entanglement during use. This facilitates gel formation at low water content, reducing the amount of water required to exert the gel's blood sugar control mechanism, thus lessening the burden on the digestive system and improving the texture of the food system.

[0078] The nano-sized thin-walled cell walls used in this invention can maintain high viscosity even at high water content. This is beneficial for improving the processability of food systems.

[0079] The nano-sized thin-walled cell walls used in this invention can maintain good stability in aqueous dispersions at room temperature, which is a significant advantage for actual food production, as it allows for more flexible requirements on production time and temperature. For example, it can be easily mixed evenly with water at room temperature before being mixed with flour or other materials for dough kneading.

[0080] Of particular note is that when the nano-sized thin-walled cell wall selected in this invention is added to the starch-like system, it not only exerts the aforementioned sugar control mechanisms (i) to (iv), but also performs particularly well in reducing rapidly digested starch, slowly digesting starch, and increasing resistant starch, thereby further improving the sugar control performance.

[0081] In summary, this invention selects nano-sized thin-walled cell walls with specific sources, crystallinity, morphology, and water dispersibility characteristics as low-GI food modifiers, thereby achieving low-GI modification of food and realizing comprehensive and excellent food performance that meets multiple requirements.

[0082] The nano-sized thin-walled cell wall of this invention is edible. It is obtained from the thin-walled cells of natural plants through a preparation method described later. This preparation method does not decompose, alter, reorganize, or modify the fibers of the thin-walled cell wall itself. No toxic or harmful substances are introduced in this preparation method, ensuring food safety.

[0083] The cellulose in the nano-sized thin-walled cell walls has a crystallinity of 80% to 95%. Preferably, the crystallinity is in the range of 90% to 95%. If the crystallinity is too low, the shelf stability may be poor. If the crystallinity is too high, it may affect its activity during use.

[0084] Nanoscale thin-walled cell walls possess one-dimensional characteristics, clearly distinguishing them from nanoparticles with granular, spherical / ellipsoidal, or two-dimensional sheet-like shapes. One-dimensionality refers to the fact that their length dimension is significantly larger than their dimensions in the other two directions. The aspect ratio is in the range of 10 to 400, more preferably 10 to 50, and even more preferably 20 to 50. Their lateral dimension is less than 100 nm, and their longitudinal dimension is greater than 1 μm. Preferably, the lateral dimension is 5 to 60 nm. Preferably, the longitudinal dimension is 1 to 10 μm. The lateral dimension refers to the largest scale in the direction perpendicular to the length direction of the one-dimensional characteristic. For example, the nanoscale thin-walled cell wall can be rod-shaped, in which case the lateral dimension is the diameter of the rod. For example, the nanoscale thin-walled cell wall can also be narrow strip-shaped, in which case the lateral dimension is the width of the strip. If the aspect ratio is too low, the nanoscale thin-walled cell wall will have insufficient activity and poor gelation performance during use. If the aspect ratio is too high, the preparation difficulty will be greater, increasing the cost.

[0085] The dispersion of nano-sized thin-walled cell walls in water has a viscosity of 200 Pa•s or higher, more preferably 2000 Pa•s or higher, and even more preferably a viscosity range of 4000 to 5000 Pa•s, when the mass concentration of nano-sized thin-walled cell walls is 0.5%. This viscosity reflects the stability of the system. Poor viscosity may affect the texture of food. In addition, excessively low viscosity may be detrimental to food processing and shaping.

[0086] The dispersion of nano-sized thin-walled cell walls in water remains stable within a temperature range of 5 to 40°C. Stability is defined as the dispersion system exhibiting no significant change in stability for at least 24 hours, preferably at least 48 hours. This facilitates its use in food processing at room temperature.

[0087] In one embodiment, the low-GI food modifier is a low-GI food modifier for starch-like systems. The term "starch-like system" has its well-known meaning in the food industry. The nano-sized thin-walled cell wall of the present invention is particularly suitable as a low-GI food modifier for starch-like systems because it has a controlling effect on starch digestion and thus reduces postprandial blood glucose elevation. Of course, the low-GI food modifier can also be used as a low-GI food modifier in other food systems.

[0088] In one implementation, the starch-like system is rice flour or flour products. Flour refers to wheat flour, and rice flour refers to rice flour. Of course, the starch-like system can also be derived from other starch-rich crops. However, flour and rice flour products, as staple foods with particularly high starch content and a large proportion of rapidly digestible starch, especially require the addition of low-GI food improvers. Moreover, the texture of flour and rice flour products is more sensitive to degradation caused by the addition of dietary fiber. More preferably, the starch-like system is rice vermicelli, noodles, or biscuits.

[0089] In one embodiment, the cell source for the nano-sized thin-walled cell wall is selected from herbaceous plants, more preferably rapeseed straw, bamboo, and seaweed. These plant sources are inherently low in cost but are highly suitable for preparing nano-sized thin-walled cell walls using the preparation method of the present invention, thus making them preferred as cell sources and significantly increasing their added value. Compared to woody plants, herbaceous plants are easier to process, but there are some difficulties in preparing nano-sized thin-walled cell walls. However, the preparation method of the present invention can overcome these difficulties.

[0090] In one embodiment, the present invention provides a low-GI food modifier characterized by comprising nano-sized thin-walled cell walls having the aforementioned features. This low-GI food modifier possesses the aforementioned beneficial properties. The low-GI food modifier may consist solely of nano-sized thin-walled cell walls, such as nano-sized thin-walled cell wall powder, or it may contain other components, as long as these components do not degrade the overall performance of the low-GI food modifier. For example, it may contain water.

[0091] In one embodiment, the low-GI food modifier is a dispersion of the nano-sized thin-walled cell wall in water at a mass concentration of 0.1% to 3%, preferably 0.3% to 2.5%, more preferably 0.5% to 2%. This dispersion allows for full activation of the nano-sized thin-walled cell wall powder while maintaining dispersion stability for use in food preparation processes.

[0092] In one embodiment, the present invention provides a method for preparing the low-GI food modifier of the present invention, the method comprising preparing the nano-thin-walled cell wall by the following steps:

[0093] A) Add natural plant cell sources to food-grade anhydrous ethanol, heat to 60 to 80°C, and react for 24 to 48 hours;

[0094] B) Add the mixture obtained in step A) to a solution of food-grade hydrogen peroxide and food-grade glacial acetic acid, and react at 60 to 80°C for 24 to 48 h to obtain bleached thin-walled cell walls.

[0095] C) The bleached thin-walled cell wall obtained in step B) is pulverized using a post-treatment including high-pressure homogenization to obtain the nano-thin-walled cell wall.

[0096] Regardless of any theoretical basis, step A) prior to bleaching is crucial in the preparation method of this invention. It promotes the exfoliation of the cell walls of the thin-walled cells from the natural plant, while simultaneously removing some ethanol-soluble substances from the thin-walled cells that might interfere with the subsequent bleaching process. By implementing step A), compared to the aforementioned Chinese patent application CN202110607105.3, the concentration of glacial acetic acid used can be reduced to approximately 60% to 80%, and the concentration of hydrogen peroxide can be reduced to below 30%, thus simplifying the process requirements.

[0097] In particular, step A) of the preparation method of the present invention can help overcome the difficulties in preparing nano-sized thin-walled cell walls from herbal plant cell sources. Compared with wood raw materials, the cell walls of herbal plant raw materials contain a relatively high amount of wax. The presence of wax hinders the reaction of hydrogen peroxide and glacial acetic acid with the cell source on the one hand, and is also prone to remaining in the final product after bleaching and pulverization, potentially affecting the properties of the food. Therefore, it is particularly advantageous for herbal plant raw materials that the present invention effectively dissolves the wax by pre-treating it thoroughly with anhydrous ethanol, reducing its adverse effects in the bleaching step, and also promoting the precipitation of cellulose from the natural plant. In addition, it also reduces the amount of wax remaining in the food improver, reducing the adverse effects on the final food product.

[0098] In one embodiment, the present invention provides a starch-like system comprising the low-GI food modifier of the present invention, wherein the low-GI food modifier is a dispersion of the nano-sized thin-walled cell wall in water at a mass concentration of 0.1% to 3%, preferably 0.3% to 2.5%, more preferably 0.5% to 2%, and the mass ratio of the low-GI food modifier to starch in the starch-like system is in the range of 1:1 to 1:5, preferably 1:2 to 1:4. The selected range allows for sufficient control of the glycemic index after starch-like system intake while maintaining food properties such as taste and stability.

[0099] In one embodiment, the starch-like system is a rice flour or wheat flour product, preferably rice vermicelli, noodles, or biscuits. Its advantages are as described above.

[0100] In one implementation, the total mass content of dietary fiber in the starch-like system is 0.5% to 1.5%. Besides nano-sized thin-walled cell walls, which serve as cellulose dietary fiber, other types of dietary fiber can also be added to the starch-like system. The total mass of dietary fiber should not be too high, otherwise it may affect the taste of the food.

[0101] Regarding the preparation of nano-sized thin-walled cell walls, more preferably, the obtained natural plant nano-sized thin-walled cell walls have a lateral dimension distribution ranging from 5 to 60 nm, a longitudinal dimension distribution ranging from 1 to 10 μm, and an aspect ratio distribution ranging from 10 to 400, more preferably from 10 to 50, and even more preferably from 20 to 50. Furthermore, preferably, their surface charge distribution ranges from -60 to -10 mV. This surface charge distribution range is beneficial for improving stability.

[0102] The preparation method of this invention can also be called an edible peeling method. The term "edible peeling method" refers to a method for preparing a safe and edible nano-sized thin-walled cell wall through treatment with food-grade reagents and mechanical processing, in which most of the lignin and part of the hemicellulose in the cell wall are "peeled" away, preserving as much of its natural microstructure of cellulose arrangement as possible. In this invention, the food-grade reagents include food-grade anhydrous ethanol, food-grade glacial acetic acid, and food-grade hydrogen peroxide.

[0103] Preferably, before step A), the process may further include: repeatedly soaking the commercially available natural plant in deionized water to remove most of the surface salts.

[0104] Preferably, in step A), the mass ratio of the natural plant material to anhydrous ethanol is 1:3 to 1:15, more preferably 1:5 to 1:10.

[0105] More preferably, the temperature in step A) of the present invention is 75 to 80°C, and the holding time is more preferably 36 to 48 h.

[0106] Preferably, in step B) of the present invention, the concentration of hydrogen peroxide solution is 10% to 30%, more preferably 15% to 25%; the concentration of glacial acetic acid solution is 60% to 80%, and the mass ratio of the two is 1:5 to 1:20; the mass ratio of natural plant raw materials to reaction solution is 1:3 to 1:5.

[0107] In step C) of this invention, a post-processing method including high-pressure homogenization is used. The high-pressure homogenization method relies on the pressurization and depressurization process of a liquid to break down the material through effects such as shearing, cavitation, and impact. The inventors have discovered that when plant cells are derived from herbaceous plants, they contain a relatively high content of silica, a high-hardness substance, compared to those derived from woody plants. Mechanical crushing using methods such as high-speed rotating cutters may result in rapid cutter wear, leading to reduced processing efficiency and potentially introducing impurity particles. High-pressure homogenization avoids these drawbacks and is therefore particularly suitable for preparing nano-sized thin-walled cell walls from herbaceous plants. Preferably, the mechanical pulverization of the bleached thin-walled cell wall dispersion includes any one or more combinations of a high-pressure homogenizer, a cell ultrasonic disruptor, and a pulper, with a pulverization time of 1 to 5 hours. Preferably, the mass concentration of the thin-walled cell wall dispersion in water is 0.5% to 2%. Preferably, the high-pressure homogenization process can be carried out for 2 to 5 hours.

[0108] The purpose of the above preparation method is to enable the nano-sized thin-walled cell walls extracted from natural plants to possess the required characteristics such as high crystallinity, high aspect ratio, and excellent mechanical and thermal stability, so as to realize the use of the present invention as a low-GI food improver.

[0109] The method of this invention extracts nano-thin-walled cell walls from natural plants without adding toxic or harmful solvents, resulting in minimal environmental pollution, low energy consumption, a simple and efficient peeling process, and food safety features.

[0110] The low-GI food improver of the present invention uses a nano-sized thin-walled cell wall with special properties. When used in food systems, especially starch-like substances, it also has the function of reducing rapidly digested starch, slowing down the digestion of starch, and increasing resistant starch.

[0111] In this invention, the process of combining low-GI food modifiers with starch and characterizing their properties may include the following steps:

[0112] Step a): Add a certain amount of deionized water or remove a certain amount of water to the prepared nano-thin-walled cell wall aqueous dispersion to adjust the mass concentration, so as to prepare a nano-thin-walled cell wall aqueous dispersion with a mass concentration of 0.1% to 3%, preferably 0.3% to 2.5%, more preferably 0.5% to 2%;

[0113] Step b): Add the nano-thin-walled cell wall aqueous dispersion obtained in step a) to starch. The nano-thin-walled cell wall aqueous dispersion and starch are compounded in a mass ratio of 1:1 to 1:5, preferably 1:2 to 1:4. Then, the mixture is uniformly mixed and dispersed by mechanical means, and then left to stand in a freezer for 30 to 60 minutes.

[0114] Step 1): Take out 5 to 10 mL or 5 to 10 g of the well-dispersed solution obtained in step b) and place it in a glass beaker. Perform rheological property testing on the material using a viscosity measurement method. For example, a Waters HR20 rheometer from TA Instruments (USA) can be used. Use a parallel plate with a diameter of 60 mm and measure the shear rate from 0.01 to 100 s⁻¹ at 8°C. -1 The change in solution viscosity and the frequency from 1 to 100 rad / s -1 Changes in the storage modulus and loss modulus of the solution.

[0115] The mechanical stirring described in step b) above can be performed using a magnetic stirrer, ultrasonic stirrer, PTFE stirrer, or cell disruptor, preferably a magnetic stirrer or cell disruptor, and more preferably a cell disruptor; the mechanical stirring rate range is 1500 to 3000 r / min. -1 Stir for 2 to 15 minutes, and let stand in the refrigerator for 10 to 15 minutes.

[0116] In this invention, nano-sized thin-walled cell walls are added to starch, forming a dense network structure with good stability between the nano-sized thin-walled cell walls and starch, which can exhibit one or more of the following effects:

[0117] i) Adding the low-GI food modifier to the desired starch-like system results in a more compact starch-like system structure;

[0118] ii) When the low-GI food modifier is added to the desired starch-like system, the viscosity and storage modulus are significantly improved;

[0119] iii) After adding the low-GI food modifier to the starch-like system and gelatinizing it, an in vitro simulated digestion experiment was conducted. As the concentration of nano-sized thin-walled cell walls extracted from natural plants increased, the content of rapidly digestible starch and slowly digestible starch decreased, while the content of resistant starch increased.

[0120] When low-GI noodle improvers are added to a liquid system of porcine pancreatic amylase, they can interact with amylase and reduce its activity.

[0121] To further understand the present invention, the application of nano-sized thin-walled cell walls in inhibiting starch digestion and their corresponding inhibitory effects are further illustrated below with reference to embodiments. The scope of protection of the present invention is not limited to the following embodiments.

[0122] Example

[0123] In this embodiment, rapeseed straw was used as a natural plant source to provide thin-walled cell walls, purchased from Huifeng Straw Agricultural Products Deep Processing Co., Ltd. The raw material appearance is as follows: Figure 1 As shown.

[0124] Example 1 of preparation of nano-thin-walled cell walls

[0125] Nanoscale thin-walled cell walls are prepared using the following steps.

[0126] First, soak 1000g of rapeseed straw in deionized water multiple times to remove most of the salt on the surface.

[0127] Subsequently, the desalted rapeseed straw was added to food-grade anhydrous ethanol and reacted at 80°C for 12 h to promote the bleachability of the rapeseed straw cell walls. The ratio of the two was 1:6.

[0128] After the rapeseed straw was washed with deionized water, it was bleached in a pre-prepared mixed solution of food-grade hydrogen peroxide aqueous solution and food-grade glacial acetic acid aqueous solution at a ratio of 1:4. The concentration of hydrogen peroxide aqueous solution was 20%, the concentration of glacial acetic acid aqueous solution was 60%, the mass ratio of the two was 1:10, the reaction time was 24 h, and the reaction temperature was 60℃.

[0129] The mixture obtained after the bleaching step separated into layers upon standing, with a floating slurry on top, a liquid on the bottom, and sediment at the bottom. The upper slurry was separated and washed with water, an appropriate amount of water was added, and then the mixture was pulverized in a pulper for 1 hour, followed by crushing in a high-pressure homogenizer for 120 minutes to obtain a nano-sized thin-walled cell wall dispersion.

[0130] Figure 2 The images show different stages of the preparation of nano-sized thin-walled cell walls from rapeseed straw. From left to right: rapeseed straw raw material, rapeseed straw reacted with food-grade anhydrous ethanol and then immersed in a bleaching solution, the bleached mixture after standing and separating into layers, and the nano-sized thin-walled cell wall dispersion after high-pressure homogenization. It can be visually observed that as the method of this invention is carried out, the size of the rapeseed straw raw material gradually decreases and becomes finer, ultimately yielding nano-sized thin-walled cell walls. As seen in the rightmost image, a uniformly dispersed, semi-transparent white dispersion is obtained.

[0131] Figure 3A scanning electron micrograph of rapeseed straw raw material is shown. It shows the morphology of the cell wall of the closely packed thin-walled cells.

[0132] Figure 4 A scanning electron micrograph of rapeseed straw raw material after image processing is shown, in which the fibrous structure in the cell wall becomes more apparent.

[0133] Figure 5 The diagram illustrates the gradual changes in the microstructure of rapeseed straw during bleaching treatment using the method of this invention. It can be seen that the lignin filling the spaces between the cellulose fibers and a portion of the hemicellulose binding the cellulose are gradually removed, and the cellulose is gradually peeled off.

[0134] Figure 6 The diagram illustrates the proportions of the three components (cellulose, hemicellulose, and lignin) in the inner core, outer shell, and overall structure of rapeseed straw, as well as their changes after bleaching and pulverization. It can be seen that after bleaching, the lignin proportion significantly decreases, the cellulose proportion significantly increases, and the hemicellulose proportion remains relatively unchanged. This indicates that the bleaching process removes most of the lignin and some of the hemicellulose from the rapeseed straw. After pulverization, the proportions of the three components do not change significantly further. The inventors have found that completely removing lignin and hemicellulose is quite difficult. Therefore, considering the higher lignin proportion in wood, this invention more preferably uses herbaceous plants as raw materials to reduce the original lignin proportion, thereby reducing the residual lignin proportion and making the nano-sized thin-walled cell walls more suitable for use as low-GI food modifiers.

[0135] Figure 7 The X-ray diffraction (XRD) curves of the obtained nano-sized thin-walled cell wall sample are shown. The characteristic peaks indicate that the main component of the sample is cellulose. The crystallinity of cellulose can be calculated from the XRD curves. Repeated preparation experiments showed that the crystallinity of cellulose obtained according to the preparation method of Example 1 was 80% to 95%.

[0136] Figure 8 This image shows a nanostructured thin-walled cell wall with one-dimensional features, observed under an electron microscope. The scale bar is at the bottom of the image, and the gradient color bar on the right represents the sample height in terms of brightness. It can be seen that it has one-dimensional features, with a lateral dimension of approximately 80 nm and a longitudinal dimension of approximately 5 μm.

[0137] The rheological properties of the obtained dispersion were tested using a HAAKE MARS 60 rotational rheometer after the concentration was adjusted to 0.5%. Parallel plates with a diameter of 60 mm were used, and shear rates were measured from 0.01 to 100 s⁻¹ at 8°C. -1 The change in solution viscosity and the frequency from 1 to 100 rad / s -1 Changes in the storage modulus and loss modulus of the solution. Figure 9 and Figure 10 The measurement results are shown separately.

[0138] Repeated experiments showed that the aqueous dispersion of the obtained nano-thin-walled cell wall had a viscosity of more than 200 Pa•s at a mass concentration of 0.5% and remained stable for more than 24 hours in a temperature range of 5 to 40 °C.

[0139] Example 2 of preparation of nano-thin-walled cell walls

[0140] Nanoscale thin-walled cell walls were prepared in essentially the same manner as in Example 1 of nanoscale thin-walled cell wall preparation, with the following differences: during the treatment with food-grade anhydrous ethanol, the reaction time was 24 h; during the bleaching process, the concentration of hydrogen peroxide aqueous solution was 30%, the concentration of glacial acetic acid aqueous solution was 80%, the volume ratio of the two was 1:20, the reaction time was 48 h, and the reaction temperature was 80 °C; during the pulverization process, the cells were pulverized in a pulper for 2 h, and then crushed in a high-pressure homogenizer for 90 minutes.

[0141] The product was subjected to the aforementioned detection and characterization, and the results were consistent with those of Example 1, which was used to prepare nano-thin-walled cell walls.

[0142] Example 1 of food improver performance

[0143] The product obtained from Example 1 of nano-thin-walled cell wall preparation was used as a low-GI food modifier in an experiment added to a starch-like system. Before addition, the content ratio of the low-GI food modifier in the dispersion was adjusted. Specifically, the product from Example 1 of nano-thin-walled cell wall preparation was dried, weighed, and its solid content was calculated. Based on the calculation result, a certain amount of water was added or evaporated to obtain an aqueous dispersion with a predetermined mass concentration of nano-thin-walled cell wall. Aqueous dispersions of nano-thin-walled cell wall with mass concentrations of 0.5%, 1%, and 1.5% were prepared in this manner as low-GI food modifier samples.

[0144] Mix the low-GI food improver samples and starch at a mass ratio of 1:2 and heat at 60 to 80°C for 30 minutes to gelatinize. Figure 11 The images show starch with only water added but no low-GI food improver and starch with low-GI food improver before heating.

[0145] The uniformly dispersed mixture obtained after gelatinization was allowed to stand in a freezer for 30 to 60 minutes. 10 g of the mixture was then placed in a glass beaker, and its rheological properties were tested using a HAAKE MARS 60 rotational rheometer. A parallel plate with a diameter of 60 mm was used, and shear rates from 0.01 to 100 s⁻¹ were measured at 8°C. -1 The change in solution viscosity and the frequency from 1 to 100 rads-1 Changes in the storage modulus and loss modulus of the solution.

[0146] Figure 12 The rheological data curves of the mixtures obtained by adding low-GI food modifiers with nano-thin-walled cell wall concentrations of 0.5%, 1%, and 1.5% to starch at a mass ratio of 1:2 are shown, illustrating the relationship between viscosity and shear rate.

[0147] Figure 13 The data curves showing the relationship between the measured energy storage modulus / loss modulus and frequency for these hybrid systems are presented.

[0148] Figure 14 The rapid viscosity analysis data curves of the mixture obtained by adding a 1% low-GI food improver to starch, measured using RVA super 4, are shown.

[0149] Figure 15 The DSC data curves are shown for the mixtures obtained by adding each low-GI food improver to starch at a mass ratio of 1:2, as measured using a DSC 204F1 fully automated differential scanning calorimeter.

[0150] Figures 12 to 14 The results show that after adding the low-GI food improver of the present invention, the overall viscosity of the gelatinized starch-like system increases, the structure becomes denser, and the stability is better.

[0151] Figure 15 The results show that the addition of the low-GI food improver of this invention increases the gelatinization temperature of starch and has a better effect on inhibiting gelatinization. Inhibiting gelatinization is beneficial for blood sugar control to achieve a low-GI diet.

[0152] Example 2 of food improver performance

[0153] The low-GI food improver sample was prepared using the same method as in Example 1 of the food improver performance test.

[0154] The samples of low-GI food improvers and porcine pancreatic amylase were mixed at a mass ratio of 10:1, stirred at room temperature, and allowed to stand at room temperature for 20 minutes after being stirred evenly to obtain a homogeneous mixed solution system.

[0155] Figure 16 The ultraviolet spectra of these mixed systems are shown, measured using a SOLID 3700 ultraviolet-visible-near-infrared spectrophotometer.

[0156] Figure 17 The fluorescence spectra of these mixed systems, measured using an XRF-1800 X-ray fluorescence spectrometer, are shown.

[0157] Figure 16 , 17 Microscopically, this indicates that nano-sized thin-walled cell walls reduce enzyme activity, thereby inhibiting digestion.

[0158] Take 1 mL of the supernatant from the obtained mixed solution system and place it in a glass beaker. Measure the activity of porcine pancreatic amylase using an enzyme-linked immunosorbent assay (ELISA) reader to calculate the data.

[0159] Figure 18 The data and enzyme activity curves of porcine pancreatic amylase in these mixed systems, measured using an ST-360 microplate reader, are shown. Figure 18 Macroscopically, this indicates that nano-sized thin-walled cell walls reduce enzyme activity, thereby inhibiting digestion.

[0160] Without relying on any theory, the low-GI food modifier of this invention can inhibit the activity of α-amylase and hinder starch digestion through physicochemical interactions and steric hindrance effects, achieving a low-GI effect. Specifically, the hydroxyl and carboxyl functional groups on the surface of the nano-thin-walled cell wall in the low-GI food modifier can directly adsorb α-amylase molecules through electrostatic interactions and hydrogen bonds, resulting in the masking of the enzyme's active site or a conformational change. In addition to inhibiting the activation of amylase molecules, the three-dimensional network structure formed by the nano-thin-walled cell wall in the starch matrix can physically block the contact between α-amylase and starch molecules, significantly reducing the enzymatic hydrolysis efficiency. Furthermore, the nano-thin-walled cell wall can also affect the gelatinization and retrogradation properties of starch by preferentially binding to amylose, further reducing the exposure of enzymatic hydrolysis sites. These synergistic effects ultimately lead to a significant reduction in the rate and extent of starch digestion. In particular, the nano-thin-walled cell wall of this invention may have a better effect on inhibiting amylase than cellulose nanocrystals obtained by conventional strong acid hydrolysis due to the retention of some of the natural cell wall structure and specific morphology.

[0161] Example 3 of food improver performance

[0162] The low-GI food improver sample was prepared and gelatinized with starch using the same method as in Example 1 of the food improver performance.

[0163] Figure 19 The contents of rapidly digestible starch, slowly digestible starch, and resistant starch in these mixtures are shown, as measured using an ST-360 microplate reader.

[0164] Figure 19 This demonstrates that the addition of low-GI food improvers reduces the content of rapidly digestible and slowly digestible starches while increasing the content of resistant starches, thus achieving a low-GI effect.

[0165] When the low-GI food modifier of the present invention is added to starch, due to the high specific surface area and the formation of a network structure by the nanoscale and one-dimensional characteristics of its nano-thin-walled cell wall, it can effectively reduce the proportion of rapidly digestible starch and slowly digestible starch in starch, increase the proportion of resistant starch, and further improve the low-GI effect.

[0166] Figure 20 A scanning electron microscope image of starch gelatinized after a low-GI food modifier was added is shown.

[0167] As can be seen, the gelatinized starch has a denser structure after the addition of low-GI food improvers. These low-GI food improvers form a three-dimensional network structure, thereby reducing the contact between enzymes and starch, inhibiting starch digestion, and thus controlling glycemic output.

[0168] Figure 21 The Fourier transform infrared spectra of these mixed systems after gelatinization, measured using a Nicolet 8700 Fourier transform infrared spectrometer, are shown.

[0169] As can be seen, all samples are between 500 and 4000 cm. -1 Similar absorption peaks were observed at various locations. No new absorption peaks were found after adding nano-sized thin-walled cell walls, indicating that there is no covalent interaction between the nano-sized thin-walled cell walls and starch.

[0170] Figure 22 The X-ray diffraction patterns of these mixed systems after gelatinization, measured using a PANalytical X'pert PRO MRD X-ray diffractometer, are shown. The samples were uniformly placed on a silicon wafer and then placed together in the X-ray diffractometer to obtain the data.

[0171] As can be seen, diffraction peaks appear near 17° and 20°, indicating that the initial crystalline structure of starch is destroyed during gelatinization. In the presence of low-GI food modifiers, the XRD peak shapes of gelatinized starch undergo some changes: the peak height at 17.0° increases, and the peak at 20.0° becomes sharper. These changes may be related to the high crystallinity of the nano-thin-walled cell walls themselves.

[0172] Example 4 of food improver performance

[0173] Cytotoxicity experiments were conducted on L929 cells, colonic epithelial cells, and gastric epithelial cells using a low-GI food modifier. The control group consisted of normally cultured cells without the low-GI food modifier. The results showed that both groups exhibited the same cell activity, demonstrating that the low-GI food modifier of this invention is non-toxic.

[0174] Figure 23 The experiment showed the cytotoxicity of the low-GI food modifier with L929 cells, colonic epithelial cells, and gastric epithelial cells.

[0175] It can be seen that the nano-sized thin-walled cell wall is non-toxic to these three cells.

[0176] Comparative Example 1

[0177] This comparative example is the same as Example 1 of the food improver performance, except that the nano-thin-walled cell walls were replaced with cellulose nanocrystals (CNCs) at a mass concentration of 0.5%. The CNCs used in this comparative example were obtained from wood using conventional methods through strong acid hydrolysis, retaining only the cellulose crystalline regions.

[0178] Figure 12 , Figure 13 The comparison of rheological data obtained in Example 1 and Comparative Example 1 of the food improver performance is shown.

[0179] Compared to adding cellulose nanocrystals, the addition of the nano-sized thin-walled cell wall of this invention results in a system with higher viscosity, storage modulus, and loss modulus. This indicates that even without considering other characteristics such as food safety, the nano-sized thin-walled cell wall of this invention offers better stability.

[0180] Comparative Example 2

[0181] This comparative example is the same as Example 2 of the performance of the food improver, except that the nano-thin-walled cell wall is replaced with cellulose nanocrystals with a mass concentration of 0.5%.

[0182] Figure 18 The comparison of amylase activity data in Example 2 and Comparative Example 2 shows the performance of the food improver. Compared with the addition of cellulose nanocrystals, the addition of nano-sized thin-walled cell walls resulted in lower amylase activity, and the amylase activity gradually decreased with increasing concentration.

[0183] Comparative Example 3

[0184] This comparative example is the same as Example 3 of the performance of the food improver, except that the nano-thin-walled cell wall is replaced with cellulose nanocrystals with a mass concentration of 0.5%.

[0185] Figure 19 The comparison of the contents of rapidly digestible starch, slowly digestible starch, and resistant starch in Example 3 and Comparative Example 3 of the food improver performance is shown. Compared with the addition of cellulose nanocrystals, the addition of nano-sized thin-walled cell walls resulted in less rapidly digestible starch and slowly digestible starch, and more resistant starch. Furthermore, with increasing concentration, the rapidly digestible starch and slowly digestible starch decreased further, and the resistant starch increased further.

[0186] Comparative Example 4

[0187] The preparation was carried out in the same manner as in Example 1 of the preparation of nano-thin-walled cells, except that the anhydrous ethanol reaction step was not performed.

[0188] The same characterization of the product showed that its hemicellulose and lignin residues were high and its one-dimensional characteristics were poor.

[0189] As can be seen, the nano-sized thin-walled cell walls obtained in this invention, when added to starch, verify that this material has the effect of inhibiting the increase of glycemic index (GI) through multiple mechanisms, and therefore has broad application prospects, especially in low-GI foods and related fields. The nano-sized cell walls extracted from natural plants in this invention, when added to starch-like systems, not only reduce the glycemic index and obtain low-GI products, but also have other comprehensive and excellent effects. This product has significant advantages and broad application prospects. In food systems, it can not only be used to develop low-glycemic index foods, help control blood sugar levels, and reduce the risk of chronic diseases, but also as a liquid thickener and stabilizer to improve the taste and stability of food. Its preparation method is simple, non-toxic, efficient, and environmentally friendly in obtaining the desired nano-sized thin-walled cell walls, with anhydrous ethanol treatment improving the preparation effect.

[0190] The above descriptions of specific embodiments and examples are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles and spirit, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. The use of nano-sized thin-walled cell walls as a low-GI food modifier, characterized in that, The nano-sized thin-walled cell walls are edible; The cellulose in the nano-thin-walled cell wall has a crystallinity of 80% to 95%. The nano-sized thin-walled cell wall has one-dimensional characteristics, with a lateral dimension of less than 100 nm and a longitudinal dimension of more than 1 μm; The dispersion of the nano-thin-walled cell wall in water has a viscosity of more than 200 Pa•s when the mass concentration of the nano-thin-walled cell wall is 0.5%, and remains stable in a temperature range of 5 to 40°C.

2. The use according to claim 1, characterized in that, The low-GI food improver is a low-GI food improver used in starch-like systems.

3. The use according to claim 2, characterized in that, The starch-like system is a rice flour or wheat flour product, preferably rice noodles, noodles, or biscuits.

4. The use according to claim 1, characterized in that, The nano-sized thin-walled cell wall is derived from herbaceous plants, preferably from rapeseed straw, bamboo, and seaweed.

5. A low-GI food improver, characterized in that, The low-GI food modifier contains nano-sized thin-walled cell walls. The nano-sized thin-walled cell walls are edible; The cellulose in the nano-thin-walled cell wall has a crystallinity of 80% to 95%. The nano-sized thin-walled cell wall has one-dimensional characteristics, with a lateral dimension of less than 100 nm and a longitudinal dimension of more than 1 μm; The dispersion of the nano-thin-walled cell wall in water has a viscosity of more than 200 Pa•s when the mass concentration of the nano-thin-walled cell wall is 0.5%, and remains stable in a temperature range of 5 to 40°C.

6. The low-GI food improver according to claim 5, characterized in that, The low-GI food improver is a dispersion of the nano-sized thin-walled cell wall in water at a mass concentration of 0.1% to 3%, preferably 0.3% to 2.5%, more preferably 0.5% to 2%.

7. A method for preparing a low-GI food improver according to claim 5 or 6, characterized in that, The method includes preparing the nano-sized thin-walled cell wall by the following steps: A) Add natural plant cell sources to food-grade anhydrous ethanol, heat to 60 to 80°C, and react for 24 to 48 hours; B) Add the mixture obtained in step A) to a solution of food-grade hydrogen peroxide and food-grade glacial acetic acid, and react at 60 to 80°C for 24 to 48 h to obtain bleached thin-walled cell walls. C) The bleached thin-walled cell wall obtained in step B) is pulverized using a post-treatment including high-pressure homogenization to obtain the nano-thin-walled cell wall.

8. A starch-like system comprising the low-GI food modifier according to claim 5 or 6, characterized in that, The low-GI food modifier is a dispersion of the nano-sized thin-walled cell wall in water at a mass concentration of 0.1% to 3%, preferably 0.3% to 2.5%, more preferably 0.5% to 2%, and the mass ratio of the low-GI food modifier to the starch in the starch-like system is in the range of 20:1 to 10:

1.

9. The starch-like system according to claim 8, characterized in that, The starch-like system is a rice flour or wheat flour product, preferably rice noodles, noodles, or biscuits.

10. The starch-like system according to claim 8, characterized in that, The total mass content of dietary fiber is 0.5% to 1.5%.

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