Rice noodles with low-GI characteristic and preparation method thereof, application of nanocrystallized thin-walled cell walls extracted from tabasheer as low-GI rice noodle modifier, and low-GI rice noodle modifier

Abstract

The present invention provides rice noodles having a low GI characteristic and a preparation method thereof, the rice noodles comprise rice flour, water and nanocrystallized thin-walled cell walls, the nanocrystallized thin-walled cell walls are extracted from tabasheer, are edible, have one-dimensional characteristics, have a lateral dimension of 100 nm or less and a longitudinal dimension of 1 [mu] m or more, and wherein the nanocrystallized thin-walled cell walls have a cross-sectional dimension of 100 nm or less and a longitudinal dimension of 1 [mu] m or more. The mass content of the nano thin-walled cell wall in the rice noodles is between 0.1% and 1.5%. The invention also provides application of the nanocrystallized thin-walled cell wall as a low-GI rice noodle modifier and the low-GI rice noodle modifier.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of food processing, more particularly, to rice noodles with low GI characteristics and a method for preparing the same, the use of nanofiber cell walls extracted from bamboo yellow as a low GI rice noodle modifier, and a low GI rice noodle modifier. BACKGROUND

[0002] Rice noodles are a common food with rice flour as the basic ingredient. Since refined rice flour is easily digested into glucose and then absorbed by the intestines, the consumption of rice noodles usually poses a risk of rapid blood sugar rise for diabetic patients and people at high risk of diabetes.

[0003] Cellulose, as the most widely distributed and most abundant natural macromolecular compound in nature, accounts for more than 50% of the carbon content of the plant kingdom and is the main structural component of plant cell walls. As a renewable carbon source, it has shown broad application prospects in the fields of energy, materials, and chemical industry.

[0004] The food field is another application field of cellulose products. Edible cellulose extracted or synthesized is a typical representative of insoluble dietary fiber, which cannot be digested by humans and has a very important significance for promoting intestinal peristalsis and defecation. Because it does not provide energy but can increase satiety, it is widely used as an additive in weight loss meals.

[0005] In addition to the above basic physiological functions, the understanding of the blood sugar control of dietary fiber is also constantly deepening. Previously, it has been recognized that the benefits of dietary fiber on blood sugar mainly lie in slowing down sugar absorption, reducing blood sugar fluctuations, and improving insulin sensitivity. It helps maintain stable blood sugar by slowing down the digestive process, regulating intestinal function, and other ways, which is particularly positive for people with diabetes or high blood sugar. When it comes into contact with water, it forms a viscous gel-like substance that encapsulates the carbohydrates in food, slowing down their decomposition and absorption speed in the intestines. At the same time, long-term intake of sufficient dietary fiber can improve the sensitivity of cells to insulin. Studies have shown that increasing dietary fiber intake can effectively reduce the risk of type 2 diabetes. Fiber regulates the balance of intestinal flora and promotes the production of short-chain fatty acids such as butyric acid, which can directly act on pancreatic beta cells to enhance insulin secretion function. Therefore, based on the above understanding, dietary fiber has been proposed as a food additive to assist in controlling blood sugar. For example, Chinese application CN202510726682.2 discloses a noodle with blood sugar control function and a preparation method, in which dietary fiber is added to flour-based food as an auxiliary blood sugar agent.

[0006] Nanocellulose refers to cellulose materials with dimensions in the nanometer range. Compared with ordinary cellulose, nanocellulose has more unique properties, such as high specific surface area, high hydrophilicity, etc., and has the potential to realize more unique functions. Some nanofiber dietary fibers have been developed to provide further functions. For example, Chinese application 202411037355.8 discloses a nanofiber burdock functional dietary fiber and a preparation method thereof, which is used to provide starch digestion inhibition and hypoglycemic activity. The method uses ultrasonic assisted complex enzyme treatment to effectively decompose the insoluble dietary fiber in burdock, change the spatial structure of the insoluble dietary fiber in burdock, and prepare nanofiber burdock functional dietary fiber with a particle size of 200 nm to 600 nm, which can inhibit the activity of amylase and glucosidase, and achieve the function of reducing blood sugar.

[0007] The current mechanisms for controlling blood sugar using dietary fiber mainly include: (i) replacing starch to provide satiety to reduce starch intake; (ii) forming a gel after absorbing water to physically wrap starch to slow down its digestion and absorption; (iii) indirectly increasing insulin sensitivity; and (iv) nanofiber by decomposing and modifying the spatial structure of the natural dietary fiber of some special plants to achieve the function of inhibiting the activity of digestive enzymes to reduce starch digestion. However, the inventors of the present application found in their research that these mechanisms also have corresponding disadvantages. Mechanism (i) causes changes in food taste due to the need to replace a large volume of starch with dietary fiber, affecting people's appetite. Mechanism (ii) has the risk of causing increased gastric burden and indigestion because it may require the simultaneous intake of a large amount of water. Mechanism (iii) relies on long-term regulation of the endocrine system, and the effect of reducing blood sugar for a single large intake of starch is not obvious. Mechanism (iv) has special requirements for plant sources and needs to perform biological enzyme hydrolysis and artificial spatial reconstruction or modification on cellulose from plant sources, and the process is complex.

[0008] In particular, for mechanism iv), the bioenzymatic method is complicated, harsh conditions, and the cost of enzyme reagents is relatively high, and there are still difficulties in the large-scale production of nanofibers, resulting in low practicability. Although in addition to the bioenzymatic method, nanocellulose can also be prepared by other methods. However, in the existing other nanocellulose preparation technologies, generally, harmful chemical reagents such as strong acid and strong oxidant are used for preparation, which has the risk of environmental pollution, and it is difficult to obtain nanoscale dietary fiber that can be used in the food field. In view of the environmental protection problem, Chinese patent application CN202110607105.3 discloses an environmentally friendly preparation and drug liquid recovery method of nanocellulose. The application solves the problem of very few types of nanocellulose by using an environmentally friendly preparation method, proposes to start from plant raw materials, use a 1:2 to 2:1 volume ratio mixed solution system of 17.5 mol / L glacial acetic acid and 30 wt% hydrogen peroxide as a treatment drug liquid, soak the raw materials, and then perform crushing, homogenization, micro-jet and grinding treatment to obtain nanocellulose, which is used in the fields of degradable plastic reinforcing agent, rheological modifier, thickening agent, etc., and further uses anhydrous copper sulfate to realize drug liquid recovery cycle. However, the application does not disclose the morphology of the prepared nanocellulose, nor does it mention that food-grade nanocellulose can be obtained by the method or that the nanocellulose is used in the food field.

[0009] In addition, for food, in addition to paying attention to its nutritional value and physiological effects on the human body, what is particularly important is its appearance and taste. If the appearance or taste of food is not good, it will weaken people's appetite, and even if the nutritional value and physiological effects are good, it is difficult to be accepted by people. For a general rice noodle food, it is ideal to have a flexible and slender shape and a smooth taste. If a rice noodle is easily broken into small pieces after cooking due to poor bending resistance, or does not have a smooth taste, it is difficult to be recognized by people. The inventors found that when conventional synthetic dietary fibers are added to rice noodle products, the broken strip rate increases after water cooking, the water cooking loss rate is high, and the taste becomes not smooth due to the change in water absorption rate. Therefore, simply adding existing dietary fibers to rice noodle raw materials in order to control blood sugar may not be able to produce satisfactory rice noodles.

[0010] There is still a need to develop rice noodles with low GI characteristics. SUMMARY

[0011] The purpose of the present application is to develop rice noodles with low GI characteristics and a preparation method thereof, to find new uses of cellulose substances as low GI rice noodle improvers and low GI rice noodle improvers.

[0012] In one aspect, the present application provides a rice noodle with low GI characteristics, wherein the rice noodle comprises:

[0013] rice powder;

[0014] nanochitinous cell wall, which is extracted from bamboo yellow, edible, having one-dimensional characteristics, transverse size below 100 nm, longitudinal size above 1 μm; and

[0015] water,

[0016] wherein the mass content of the nanochitinous cell wall in the rice noodles is between 0.1% and 1.5%.

[0017] Preferably, the rice noodles comprise a mixture of a dispersion of the nanochitinous cell wall in water and rice powder, wherein the mass ratio of the dispersion to rice powder is in the range of 1 : 1 to 1 : 2, and the mass concentration of the nanochitinous cell wall in the dispersion is between 0.3% and 3%, preferably between 0.4% and 2.5%, more preferably between 0.5% and 2%.

[0018] Preferably, the total mass content of dietary fiber in the rice noodles is between 0.1% and 1.5%.

[0019] Preferably, the rice noodles comprise the following ingredients by mass percentage:

[0020] 0.1% to 1.5% of the nanochitinous cell wall,

[0021] 35% to 60% of rice powder,

[0022] 35% to 55% of water.

[0023] Preferably, the rice noodles further comprise a mixture of soybean protein and corn starch in the balance.

[0024] In another aspect, the present application provides a preparation method of the above rice noodles, comprising:

[0025] uniformly mixing the nanochitinous cell wall, rice powder and water and forming into rice noodles,

[0026] wherein the nanochitinous cell wall is prepared by the following steps:

[0027] A) adding bamboo yellow of natural bamboo into food-grade anhydrous ethanol, heating to 60 to 80 °C, and reacting for 24 to 48 h;

[0028] B) adding the mixture obtained in step A) into a solution of mixed food-grade hydrogen peroxide and food-grade glacial acetic acid, reacting at 60 to 80 °C for 24 to 48 h to obtain bleached cell wall;

[0029] C) using post-treatment including high-pressure homogenization to crush the bleached cell wall obtained in step B) to obtain the nanochitinous cell wall.

[0030] In yet another aspect, the present application provides use of the nano-sized parenchymal cell wall as a low GI rice noodle modifier, wherein,

[0031] The nano-sized parenchymal cell wall is edible, and has a one-dimensional feature with a lateral dimension below 100 nm and a longitudinal dimension above 1 μιη.

[0032] In yet another aspect, the present application provides a low GI rice noodle modifier, wherein,

[0033] The low GI rice noodle modifier comprises the nano-sized parenchymal cell wall, which is edible, and has a one-dimensional feature with a lateral dimension below 100 nm and a longitudinal dimension above 1 μιη.

[0034] Preferably, the low GI rice noodle modifier is a dispersion of the nano-sized parenchymal cell wall in water with a mass concentration of 0.3% to 3%, preferably 0.4% to 2.5%, more preferably 0.5% to 2%.

[0035] The rice noodle discovered by the present application has at least the benefits of excellent low GI property, natural ingredients, low breakage rate, low cooking loss rate, and maintained or even improved smooth mouthfeel.

[0036] The method for preparing the rice noodle discovered by the present application can simply, efficiently, and lowly produce the above rice noodle with low energy consumption and no pollution.

[0037] The use discovered by the present application has at least the benefits of using the unmodified and edible nano-sized parenchymal cell wall derived from natural bamboo as a low GI rice noodle modifier, which has a low breakage rate and cooking loss rate due to its special source and morphology, and has high low GI effect in practice. The low GI rice noodle modifier discovered by the present application has corresponding benefits. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A transmission electron microscope photo of the nano-sized parenchymal cell wall prepared from bamboo yellow according to the present application is shown.

[0039] Figure 2 UV spectra obtained from testing the experimental group with nano-sized parenchymal cell wall added to amylase and the blank group without nano-sized parenchymal cell wall added to amylase are shown.

[0040] Figure 3 Fluorescence spectra obtained from testing the experimental group with nano-sized parenchymal cell wall added to amylase and the blank group without nano-sized parenchymal cell wall added to amylase are shown.

[0041] Figure 4 The contents of rapidly digestible starch, slowly digestible starch and resistant starch obtained from the test of the experimental group of rice noodles to which the low GI rice noodle modifier with a nano-sized parenchymal cell wall mass concentration of 1% was added and the blank group of rice noodles to which no nano-sized parenchymal cell wall was added are shown.

[0042] Figure 5 The data of noodle breakage rate, water boiling loss rate and water absorption rate obtained from the test of the experimental group of rice noodles to which the low GI rice noodle modifier with a nano-sized parenchymal cell wall mass concentration of 1% was added and the blank group of rice noodles to which no nano-sized parenchymal cell wall was added are shown. DETAILED DESCRIPTION

[0043] In view of the problems in the related art, the inventors of the present application have developed a rice noodle that has excellent low GI characteristics, is natural in composition, has a low breakage rate, a low water boiling loss rate, and maintains a smooth mouthfeel of the rice noodle.

[0044] In one embodiment, the present application provides a rice noodle having low GI characteristics, the rice noodle comprising:

[0045] rice flour;

[0046] a nano-sized parenchymal cell wall, the nano-sized parenchymal cell wall being edible, having a one-dimensional feature, a lateral dimension of less than 100 nm, and a longitudinal dimension of more than 1 μm; and

[0047] water,

[0048] wherein the mass content of the nano-sized parenchymal cell wall in the rice noodle is between 0.1% and 1.5%.

[0049] For glycemic control in diabetic patients, how to reasonably control the glycemic index (GI, also commonly known as the glycemic index) through meals is a core problem. When attempting to modify food by adding cellulose dietary fiber, it is desirable that the cellulose is kept in a natural state as much as possible, can sufficiently control the GI curve after eating, does not add to the burden on the stomach and intestines, and does not adversely affect the mouthfeel of the food itself. In addition, when using a low GI food modifier, it is desirable that the necessary characteristics of the food itself are improved after the addition of the modifier, or at least no adverse effects are produced.

[0050] The term "rice noodle" has its meaning known in the food industry. The nano-sized parenchymal cell wall of the present application is particularly suitable as a low GI rice noodle modifier for rice noodles because it has a controlling effect on the digestion of rice noodles and thus reduces the postprandial rise in blood glucose.

[0051] Rice noodles are rice flour products. Rice flour is rice powder. Rice noodles are staple foods with a particularly high starch content and a high proportion of rapidly digestible starch, and therefore require the addition of a low GI modifier. It is important for rice noodles to maintain or further reduce their breakage rate and maintain or enhance their smooth mouthfeel during the improvement process. However, the breakage rate, cooking loss rate and mouthfeel of rice noodles are sensitive to deterioration due to the addition of dietary fiber.

[0052] The inventors of the present application have found the use of a processed parenchymal cell wall as a cellulose-based low GI rice noodle modifier. The parenchymal cell wall is a nano-sized parenchymal cell wall that retains some of its natural structure. The inventors of the present application have found that, compared to the dietary fibers available in the related art, the nano-sized parenchymal cell wall proposed in the present application as a low GI rice noodle modifier not only provides the same or better glycemic control effect, but also provides other beneficial effects for rice noodles and reduces side effects. Specifically, when used in rice noodles, it is beneficial for the rice noodles to have a low breakage rate, resulting in a low cooking loss rate of the rice noodles, and also maintaining or even enhancing the smooth mouthfeel of the rice noodles.

[0053] Bamboo is a very abundant plant resource in China. It is a forestry economic crop. According to its utilization purposes, it can be mainly divided into bamboo shoots, timber, bamboo shoots and timber, ecological forest bamboo, etc. On the basis of the traditional use of bamboo, new uses are developed to fully utilize and enhance the economic value of bamboo, which is of great help to the economic development of China. At present, the edible use of bamboo is basically limited to bamboo shoots, and the development of food use other than bamboo shoots is still basically in a blank state.

[0054] Among the various parts of bamboo, bamboo yellow is not suitable for consumption even after processing and cooking due to the presence of a large amount of wax, bamboo film and other impurities, which are difficult to digest. Bamboo yellow is widely used in the fields of building materials and furniture, but is rarely consumed, and is generally considered unrelated to the edible use. However, the inventors of the present application have noticed that bamboo yellow contains a large amount of parenchymal cells, and the parenchymal cells contain a large amount of fiber components, which is a rich source of cellulose. Therefore, if edible fiber components can be extracted from natural parenchyma and then applied to the food field, the use of bamboo can be greatly expanded, which has great practical significance.

[0055] Parenchymal cells are one of the basic building blocks of bamboo. Parenchymal cells are basically composed of cell walls and cytoplasm contained in the cell walls, wherein the cell walls mainly contain cellulose, hemicellulose and lignin, and also contain inorganic matter (ash) and other extracts. Compared with the cell walls of woody products such as wood, the inorganic matter silicon dioxide content in the parenchymal cell wall is higher, and the wax content in the extract is higher.

[0056] 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.

[0057] The term "low-GI rice noodle improver" refers to a class of functional rice noodle additives that significantly reduce the glycemic index (GI) of food by adjusting the physical structure, chemical composition, or digestible properties of rice noodles. Its core objective is to promote a gradual rise in post-meal blood sugar levels.

[0058] 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 starches are 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 starches are 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 starches are not digested and absorbed by the small intestine at all, but directly enter the large intestine where they are fermented by gut microbiota, do not raise blood sugar, have prebiotic effects, and can improve gut health and metabolism (such as cold rice, raw bananas, and beans).

[0059] The breaking resistance of rice noodles can be measured by the breakage rate. The cooking breakage rate refers to the percentage of rice noodles that break after cooking. Generally speaking, the lower the breakage rate, the better the quality of the rice noodles.

[0060] The boiling loss rate refers to the percentage of solid matter dissolved in the water during the cooking process of rice noodles, relative to the original dry weight of the rice noodles. Generally speaking, the lower the boiling loss rate, the better the quality of the rice noodles.

[0061] The water absorption rate of rice noodles refers to the percentage of water content in cooked rice noodles relative to their original dry weight.

[0062] This invention provides a method for adding a special nano-sized thin-walled cell wall as a low-GI rice noodle improver to rice noodle formulations, resulting in rice noodle products with low-GI properties. The nano-sized thin-walled cell wall is edible and possesses one-dimensional characteristics, with a lateral dimension below 100 nm and a longitudinal dimension above 1 μm.

[0063] The nanochitinous cell wall added in the instant rice of the present application is a kind of cellulose product. Compared with other kinds of cellulose products, one of the features of the nanochitinous cell wall of the present application is that it is edible and can be prepared from low-cost natural plant sources by simple and non-polluting means, so it can be used as an instant rice modifier in an economic and safe manner. Another feature is that it includes chitinous cell walls derived from natural bamboo yellow, rather than artificially synthesized or modified products. It is a nanoscale fragment of chitinous cell wall from which most of the lignin and part of the hemicellulose has been removed, which can retain some of the microstructure features of the natural chitinous cell wall, such as its thickness range, the arrangement of cellulose fibers, etc., without reorganizing or modifying the fibers. At the same time, it is also nanosized. Without being bound by any theory, the nanosized morphology can achieve better blood glucose control effect, and by nanosizing the fibers, the particle size becomes smaller and the dispersion performance in water becomes better, which can make the instant rice have a delicate taste and better toughness. The third feature is that it has a one-dimensional feature and a high aspect ratio. Without being bound by any theory, this one-dimensional feature has good activity when used to exert its low GI performance, and is particularly beneficial to instant rice which is easy to form, easy to bend and not easy to break when composed of rice flour and water, and maintains or even improves the smooth taste of instant rice. Good taste may be related to the water absorption and gel formation capacity of the nanochitinous cell wall. The fourth feature is that it has a stronger ability to convert rapidly digestible starch and slowly digestible starch into resistant starch, providing better low GI performance.

[0064] As described above, a low GI instant rice modifier that is practical and can be well received by people needs to meet a variety of requirements to provide more benefits or reduce adverse effects to the instant rice and the instant rice preparation process on the premise that the blood glucose control mechanism is fully exerted, and a balance is achieved among the various required properties. The nanochitinous cell wall of the present application can achieve these purposes.

[0065] The nanochitinous cell wall of the present application is edible first of all. It is prepared from the chitinous cells of natural bamboo yellow by the preparation method described below. The chitinous cells have a high wax content, so there are difficulties in preparing the nanochitinous cell wall by chemical methods. However, the preparation method of the present application can overcome these difficulties. The preparation method successfully extracts edible chitinous cell walls from natural bamboo yellow with high impurity content, and does not introduce toxic and harmful substances in the process, ensuring food safety. The nanochitinous cell wall of the present application not only retains the natural properties of the chitinous cell wall, but also is nanosized. The nanochitinous cell wall of the present application is prepared from bamboo by a process that has low environmental pollution, low energy consumption and simple and efficient flow, and also has an advantage in cost.

[0066] Cellulose includes natural cellulose and artificially synthesized, recombined or modified cellulose. For example, the aforementioned nano-sized burdock functional dietary fiber belongs to the latter. It biologically decomposes insoluble dietary fiber in burdock and changes its spatial structure. Artificially synthesized, recombined or modified fiber can achieve special functions. However, in the food field, consumers usually have a preference for pure natural products or non- deeply processed products close to the natural state, and would rather sacrifice part of the functionality for this, so synthetic, recombined or modified non-natural dietary fiber often cannot meet the requirements of consumers. The nano-sized parenchymal cell wall of the present application comes from a natural plant source, and the fiber in the natural cell wall is not decomposed, changed in spatial structure, recombined or modified, and at least part of the microstructure of the natural parenchymal cell wall can be retained, closer to the natural state of the raw material, and can also provide sufficient sugar control functionality, meeting the needs of consumers for natural products or products close to the natural state.

[0067] Although no synthetic, recombined and modified means are used, the nano-sized parenchymal cell wall of the present application is smaller in size compared with general dietary fiber products, and at least one dimension reaches the nanometer level. Without being bound by any theory, the nano-sized parenchymal cell wall exposes more active groups, which makes it better dispersed in water, and at the same time forms more hydrogen bonds, van der Waals forces and other actions with starch, significantly increasing the viscosity of the prepared rice noodles. Further, the rice noodles prepared using the nano-sized parenchymal cell wall have a better blood glucose control effect, making the rice noodles have a lower broken strand rate and a water loss rate, and at the same time have a better taste.

[0068] Compared with other forms of dietary fiber products, the present application uses nanofibrillated cell wall with one-dimensional characteristics and high aspect ratio and transverse size below 100 nm. The nanofibrillated cell wall has one-dimensional characteristics, which is significantly different from the shape of nanoparticles such as granular, spherical / ellipsoidal, two-dimensional sheet, etc. The one-dimensional characteristics refer to the length dimension being much larger than the size of the other two directions. The aspect ratio is in the range of 10 to 400, more preferably in the range of 10 to 200, more preferably in the range of 10 to 100. The transverse size is below 100 nm, and the longitudinal size is above 1 pm. Preferably, the transverse size is in the range of 5 to 60 nm. Preferably, the longitudinal size is in the range of 1 to 10 pm. The transverse size refers to the largest scale in the direction perpendicular to the length direction of the one-dimensional characteristics. For example, the nanofibrillated cell wall can be rod-shaped, and the transverse size is the diameter of the rod. For example, the nanofibrillated cell wall can also be narrow strip-shaped, and the transverse size is the width of the strip. When the nanofibrillated cell wall of this form is added to a solvent such as water, it can quickly combine with water and be fully activated due to the high specific surface area formed by the one-dimensional characteristics of the high aspect ratio, and quickly exert its blood glucose control mechanism. The high aspect ratio also makes the one-dimensional fiber characteristics more obvious, and it is possible to appear in the form of curling, entanglement, etc. during use, which is beneficial to the good formability, low breakage rate and smooth taste of the rice noodles. If the aspect ratio is too low, the nanofibrillated cell wall will not be active enough when used, and the gelation performance will be poor. If the aspect ratio is too high, the preparation will be difficult, and the cost will be increased.

[0069] It is particularly noteworthy that the nanofibrillated cell wall selected by the present application performs particularly well in reducing rapidly digestible starch, slowly digestible starch and increasing resistant starch when added to rice noodles, on the basis of exerting the aforementioned sugar control mechanism, thereby further improving the sugar control performance.

[0070] In summary, the present application selects a certain content of nanofibrillated cell wall with a specific source and form as a low GI rice noodle modifier to prepare rice noodles, which realizes the development of the edible use of the thin-walled cell wall, realizes the improvement of the low GI characteristics of the rice noodles, and realizes the comprehensive excellent performance of the rice noodles taking into account various requirements. The prepared rice noodles have excellent low GI characteristics, qualified breakage rate and cooking loss rate, and also maintain or even improve the smooth taste of the rice noodles.

[0071] In one embodiment, the rice noodles comprise a mixture of a dispersion of the nanofibrillated cell wall in water and rice flour, wherein the mass ratio of the dispersion to rice flour is in the range of 1:1 to 1:2, preferably 1:1.3-1:1.7, and the mass concentration of the nanofibrillated cell wall in the dispersion is 0.3% to 3%, preferably 0.4% to 2.5%, more preferably 0.5% to 2%. The selected range can sufficiently control the glycemic index after the intake of the rice noodles, and make the rice noodles have low breakage rate, low cooking loss rate and good taste.

[0072] In one embodiment, the total mass content of dietary fiber in the rice noodles is 0.1% to 1.5%, preferably 0.5% to 1.5%. In addition to the nanofiberized parenchyma cell wall as the cellulose-based dietary fiber, other types of dietary fiber can also be added to the rice noodles. The total mass of dietary fiber should not be too high, otherwise it may affect the breaking rate, cooking loss rate and mouthfeel of the rice noodles.

[0073] In one embodiment, the rice noodles comprise the following ingredients by mass percentage:

[0074] 0.1% to 1.5% of the nanofiberized parenchyma cell wall,

[0075] 35% to 60% of rice flour,

[0076] 35% to 55% of water.

[0077] The combination of the above rice flour, water and nanofiberized parenchyma cell wall can produce rice noodles with good overall performance.

[0078] Preferably, in the formula, the balance ingredients (if any) other than the nanofiberized parenchyma cell wall, rice flour and water can be soy protein, corn starch, etc. This formula can achieve particularly good overall technical effects, and the specific technical effects are that the glycemic index after rice noodles intake can be fully controlled, and the properties required by rice noodles such as breaking rate, cooking loss rate and mouthfeel are still maintained.

[0079] The present application also provides a method for preparing rice noodles. The rice noodles of the present application can be prepared by the conventional process of mixing raw materials and then forming, but the raw materials contain the aforementioned nanofiberized parenchyma cell wall. Specifically, the rice noodles can be prepared by extrusion molding. First, the rice flour is mixed with the aqueous dispersion of the nanofiberized parenchyma cell wall, kneaded into a rice noodle raw material mixture in the form of a lump, then repeatedly pressed with a noodle press or rolling pin, and then extruded to form the rice noodle product of the present application. In actual cooking, the above-mentioned rice noodle raw material mixture can be directly extruded into boiling water, and it will float and cook. The rice noodles of the present application can also be pre-cooked before cooking, to facilitate storage and subsequent cooking. Accordingly, the present application also provides a cooked and dried rice noodle product, which is obtained from the above-mentioned rice noodles by a method commonly used in the related art, which is beneficial for long-term storage.

[0080] In the preparation method of the present application, the nanofiberized parenchyma cell wall is prepared by the following steps:

[0081] A) Add natural bamboo yellow to food-grade anhydrous ethanol, heat to 60 to 80°C, and react for 24 to 48 h;

[0082] B) adding the mixture obtained from step A) into a solution of food-grade hydrogen peroxide and food-grade glacial acetic acid mixed, and reacting at 60 to 80 °C for 24 to 48 h to obtain bleached cell walls of parenchyma cells;

[0083] C) pulverizing the bleached cell walls of parenchyma cells obtained from step B) using post-treatment including high-pressure homogenization to obtain the nano-sized cell walls of parenchyma cells.

[0084] Depending on the specific situation, steps A) and B) can be carried out under normal pressure or under appropriate pressurization.

[0085] Without being bound to any theory, step A) before bleaching in the preparation method of the present application is important. It can facilitate the natural bamboo yellow to separate the cell walls of its parenchyma cells, and at the same time, remove some substances in the parenchyma cells that interfere with the subsequent bleaching process in advance. By implementing step A), compared with the aforementioned Chinese patent application CN202110607105.3, the concentration of glacial acetic acid used can be reduced to about 60% to 80%, and the concentration of hydrogen peroxide can also be reduced to less than 30%, reducing the process requirements.

[0086] In particular, step A) of the preparation method of the present application can help overcome the difficulty of preparing nano-sized cell walls of parenchyma cells from herbaceous plant cell sources. Compared with wood raw materials, herbaceous plant raw materials contain a relatively high amount of waxes in their cell walls. The presence of waxes hinders the reaction of hydrogen peroxide and glacial acetic acid on the cell source on the one hand, and is easily left in the final product after bleaching and pulverization, which has a potential impact on the properties of rice noodles. Therefore, it is particularly advantageous for herbaceous plant raw materials that the present application can effectively dissolve waxes by pre-treating with absolute ethanol at an elevated temperature of 60 to 80 °C, reducing their adverse effects in the bleaching step, and also facilitating the natural plant to separate cellulose. In addition, it also reduces the residual waxes in the rice noodle improver, reducing the adverse effects on the final rice noodle product.

[0087] The ethanol treatment is carried out under heating conditions at 60 to 80 °C. This temperature range is advantageous for achieving the purpose of pre-treatment. The boiling point of ethanol under normal pressure is 78.3 °C. When the reaction is carried out in a closed reactor, its boiling point can rise due to the increase in pressure. Heating and pressure can be appropriately controlled to allow the reaction to take place within the desired temperature range.

[0088] Regarding the preparation of nano-sized cell walls of parenchyma cells, more preferably, the transverse size distribution of the obtained nano-sized cell walls of parenchyma cells of natural plants ranges from 5 to 60 nm, the longitudinal size distribution ranges from 1-10 pm, and the aspect ratio distribution ranges from 10 to 400, more preferably 10 to 50, more preferably 20-50.

[0089] The preparation method of the present application can also be referred to as an edible peeling method. The term "edible peeling method" refers to a safe and edible preparation method of nanoscale parenchymal cell walls obtained by treating and mechanically treating food-grade reagents, in which most of the lignin and part of the hemicellulose in the cell wall are "peeled off" without changing the natural microstructure of the cellulose arrangement as much as possible. In the present application, food-grade reagents include food-grade anhydrous ethanol, food-grade glacial acetic acid and food-grade hydrogen peroxide.

[0090] Preferably, before step A), it can also include multiple soaking of the commercially available natural plants with deionized water to remove most of the salt on the surface. Excessive salt will interfere with the subsequent preparation.

[0091] Preferably, in step A), the mass ratio of the natural plant raw material to anhydrous ethanol is 1:3 to 1:15, preferably 1:5 to 1:10.

[0092] More preferably, the temperature in step A) of the present application is 75 to 80°C, and the holding time is more preferably 36 to 48 h.

[0093] Preferably, in step B) of the present application, the concentration of the hydrogen peroxide solution is 10% to 30%, more preferably 15% to 25%; the concentration of the glacial acetic acid solution is 60% to 80%, and the mass ratio of the mixture of the two is 1:5 to 1:20; the mass ratio of the natural plant raw material to the reaction solution is 1:3 to 1:5.

[0094] In step C) of the present application, post-treatment including high-pressure homogenization is used. High-pressure homogenization crushing method relies on the process of liquid pressurization and pressure release to complete the crushing of materials through effects such as shearing, cavitation, and impact. The inventors found that when the plant cell source comes from herbaceous plants, compared with woody plant sources, it contains a relatively high content of silicon dioxide, which is a high-hardness substance. If mechanical crushing such as high-speed rotating cutter head is used, the cutter head may quickly wear out, resulting in reduced processing efficiency and potentially introducing impurity particles. High-pressure homogenization can avoid these shortcomings, so it is particularly suitable for preparing nanoscale parenchymal cell walls from herbaceous plants. Preferably, the mechanical crushing of the bleached parenchymal cell wall dispersion includes any one or a combination of high-pressure homogenizer, cell ultrasonic crusher, and beater, and the mechanical crushing time is 1 to 5 h. Preferably, the mass concentration of the dispersion of the parenchymal cell wall in water is 0.5% to 2%. Preferably, the high-pressure homogenization process can be carried out for 2 to 5 hours.

[0095] The above preparation method can achieve the desired high aspect ratio of the nanoscale parenchymal cell wall extracted from natural plants, and retain the cellulose and hemicellulose with low GI effect, to achieve the use of the present application as a low GI noodle improver.

[0096] By the method of the present application, in the process of extracting the nano-sized parenchyma cell wall required by the present application from bamboo yellow, no toxic and harmful solvent is added, the environmental pollution is small, the energy consumption is low, the stripping process is simple and efficient, and the obtained nano-sized parenchyma cell wall has the characteristics of food safety, etc.

[0097] In one embodiment, the present application provides the use of the nano-sized parenchyma cell wall as a low GI rice noodle modifier, which has the aforementioned characteristics. The use of the nano-sized parenchyma cell wall in rice noodles can achieve the aforementioned beneficial effects.

[0098] In one embodiment, the present application provides a low GI rice noodle modifier comprising the nano-sized parenchyma cell wall having the aforementioned characteristics. Such a low GI rice noodle modifier has the aforementioned beneficial effects. The low GI rice noodle modifier can consist only of the nano-sized parenchyma cell wall, for example, it can be a nano-sized parenchyma cell wall powder, or it can contain other ingredients as long as these ingredients do not make the overall performance of the low GI rice noodle modifier worse. For example, it can contain water.

[0099] In one embodiment, the low GI rice noodle modifier is a dispersion of the nano-sized parenchyma cell wall in water with a mass concentration of 0.3% to 3%, preferably 0.4% to 2.5%, more preferably 0.5% to 2%. Such a dispersion can fully activate the nano-sized parenchyma cell wall powder while still maintaining dispersion stability to facilitate use in the rice noodle preparation process.

[0100] The low GI rice noodle modifier of the present application uses nano-sized parenchyma cell wall with special properties, and when used in combination with rice flour, it also has the function of particularly reducing rapidly digestible starch, slowly digestible starch and increasing resistant starch.

[0101] In the present application, the process of combining the low GI rice noodle modifier with rice flour and its performance characterization can include the following steps:

[0102] Step a): adjust the mass concentration by adding a certain amount of deionized water or removing a certain amount of water to the prepared nano-sized parenchyma cell wall aqueous dispersion to prepare a nano-sized parenchyma cell wall aqueous dispersion with a mass concentration of 0.3% to 3%, preferably a concentration of 0.4% to 2.5%, more preferably 0.5 to 2%;

[0103] Step b): add the nano-sized parenchyma cell wall aqueous dispersion obtained in step a) to rice flour, the nano-sized parenchyma cell wall aqueous dispersion and rice flour are compounded in a mass ratio of 1:1 to 1:2, preferably 1:1.3 to 1:1.7, then uniformly mixed and dispersed by mechanical means, and then can be placed in a freezer for 30 to 60 min;

[0104] The mechanical stirring in step b) above can use a magnetic stirrer, an ultrasonic stirrer, a polytetrafluoroethylene stirrer, or a cell disruptor, preferably a magnetic stirrer and a cell disruptor, and more preferably a cell disruptor; the rate of the mechanical stirring ranges from 1500 to 3000 r / min -1 The stirring time is 2 to 15 min, and the standing time in the refrigerator is preferably 10 to 15 min.

[0105] In order to further understand the application, the application of the nanofiber cell wall in the field of inhibiting starch digestion and the corresponding inhibitory effect, as well as the preparation process and performance of the instant rice of the application, are further described below in combination with examples. The protection scope of the application is not limited by the following examples.

[0106] Examples

[0107] In the examples, bamboo yellow is used as a natural plant source to provide thin-walled cell walls, which is purchased from the bamboo original home store on Taobao.

[0108] In the example, the characterization experiment method of the target performance parameter uses the method commonly used in the art.

[0109] Example 1 for preparing nanofiber cell walls

[0110] The nanofiber cell walls are prepared by the following steps.

[0111] First, 1000 g of bamboo yellow is soaked in deionized water for multiple times to remove most of the salt on the surface.

[0112] Then, the desalted bamboo yellow is added to food-grade anhydrous ethanol, and reacted at 80°C for 12 h in a reaction container to promote the dissolution of the wax on the surface of the bamboo yellow, and the ratio of the two is 1:6.

[0113] After the reaction, the bamboo yellow is washed with deionized water, and then put into the mixed solution of food-grade hydrogen peroxide aqueous solution and food-grade glacial acetic acid aqueous solution at a ratio of 1:4 for bleaching. The concentration of the hydrogen peroxide aqueous solution is 20%, the concentration of the glacial acetic acid aqueous solution is 60%, the mass ratio of the mixture is 1:10, the reaction time is 24 h, and the reaction temperature is 60°C.

[0114] After the bleaching step, the obtained mixture is allowed to stand and stratify, the upper layer is a floating slurry-like material, the lower layer is a liquid, and the bottom layer is a precipitate. The upper layer of the slurry-like material is separated and washed with water, an appropriate amount of water is added, then crushed in a beater for 1 h, and then broken by a high-pressure homogenizer for 120 minutes to obtain a nanofiber cell wall dispersion.

[0115] Figure 1An image of the nanochitinous cell wall showing the one-dimensional features observed under transmission electron microscope is shown. The scale bar is shown at the bottom of the image. It can be seen that it has one-dimensional features with lateral dimension less than 100 nm and longitudinal dimension greater than 1 μιη.

[0116] Nanochitinous cell wall preparation example 2

[0117] Nanochitinous cell wall was prepared in substantially the same manner as in nanochitinous cell wall preparation example 1, except that during the food grade anhydrous ethanol treatment, the reaction time was 24 h; during the bleaching, the concentration of the hydrogen peroxide aqueous solution was 30%, the concentration of the glacial acetic acid aqueous solution was 80%, and the volume ratio of the mixture of the two was 1:20, and the reaction time was 48 h, and the reaction temperature was 80°C; and during the pulverization, the pulverization in the beater was 2 h, and the crushing by the high pressure homogenizer was 90 min.

[0118] The product was subjected to the aforementioned detection and characterization, and the results were consistent with those of nanochitinous cell wall preparation example 1.

[0119] Low GI rice noodle modifier performance example 1

[0120] The product from nanochitinous cell wall preparation example 1 was used as a low GI rice noodle modifier to be added to starch for testing. Before the addition, the proportion of the low GI rice noodle modifier in the dispersion was adjusted. Specifically, the product from nanochitinous cell wall preparation example 1 was taken, the solid content was calculated by weighing after drying, and a certain amount of water was added or evaporated according to the calculation result to obtain a water dispersion of a predetermined mass concentration of nanochitinous cell wall. In this way, a water dispersion of nanochitinous cell wall with a mass concentration of 1% was prepared as a low GI rice noodle modifier sample.

[0121] The prepared low GI rice noodle modifier sample and porcine pancreatic amylase were mixed in a mass ratio of 10:1, stirred at room temperature, and after uniform stirring, the mixture was left to stand at room temperature for 20 min to obtain a uniformly mixed solution system.

[0122] Figure 2 An ultraviolet spectrum of the mixture system measured using a UV-visible near infrared spectrophotometer SOLID 3700 is shown.

[0123] Figure 3 A fluorescence spectrum of the mixture system measured using an X-ray fluorescence spectrometer XRF-1800 is shown.

[0124] The low GI food modifier sample and rice flour were mixed in a mass ratio of 1:2, and heated at 60 to 80°C for 30 min for gelatinization.

[0125] Figure 4The contents of rapidly digestible starch, slowly digestible starch and resistant starch of the experimental group mixed system are shown, which are measured by using an ST-360 enzyme label instrument. Figure 4 It is illustrated that after adding the low GI rice noodle modifier, the contents of rapidly digestible starch and slowly digestible starch in the rice flour are reduced, the content of resistant starch is increased, and the low GI effect is achieved.

[0126] The rice noodle embodiment 1 with low GI characteristics

[0127] First, 64 g of rice flour is added to 36 g of 1% nanoscale parenchymal cell wall water dispersion and mixed evenly, kneaded into a ball, and then repeatedly pressed by a noodle press, and then shaped into a strip to obtain the rice noodle product of the application, i.e. the experimental group rice noodle.

[0128] Figure 5 The rice noodle water boiling broken strip rate, water boiling loss rate and water absorption rate data of the experimental group rice noodle obtained by adding the low GI rice noodle modifier with a nanoscale parenchymal cell wall mass concentration of 1% are shown.

[0129] Rice noodle water boiling broken strip rate test: 50 rice noodles with a length of 20 cm are selected, after boiling in 500 mL of boiling water for 1 min, the rice noodle samples are fished out, filtered and dried, the number of rice noodle strips above 10 cm (x1) is recorded, and the broken strip rate is calculated according to the following formula:

[0130] Broken strip rate / % =

[0131] In the formula, x1 is the number of rice noodle strips above 10 cm.

[0132] Rice noodle water boiling loss rate test: the water content (W) of the rice noodle is determined, about 100 g (±0.01) of rice noodle sample (M0) is weighed, boiled in 750 mL of boiling water for 5 min, the rice noodle is fished out, the soup is made up to 500 mL, 50 mL is taken to a constant weight container (M1), and then placed in a 105±2 ℃ drying condition until the constant weight (M2), and the water boiling loss value is calculated according to the following formula:

[0133] Water boiling loss rate / % =

[0134] In the formula, M0 is the mass of the rice noodle sample; M1 is the mass of the constant weight container; M2 is the sum of the mass of the constant weight container and the solid content of the removed soup; W is the water content of the rice noodle; and 10 is the conversion coefficient of the test sample.

[0135] Rice noodle water absorption rate test: the water content (W) of the rice noodle is determined, about 100 g (±0.01) of rice noodle sample (M0) is weighed, boiled in 750 mL of boiling water for 5 min, the rice noodle is fished out and rinsed with cold water for 30 s, filtered and dried, and the mass is recorded as (M3), and the water absorption rate is calculated according to the following formula:

[0136] Water absorption rate / % =

[0137] In the formula: M0 is the mass of the rice noodle sample; M3 is the mass of the rice noodle after boiling; and W is the moisture content of the rice noodle.

[0138] From the experimental results, it can be seen that after the low GI rice noodle modifier of the present application is added to starch, due to the nanoscale and one-dimensional characteristics of the nanosized parenchyma cell wall, which has a high specific surface area and forms a network structure, the proportion of rapidly digestible starch and slowly digestible starch in the starch can be effectively reduced, the proportion of resistant starch is increased, and the low GI effect is further improved.

[0139] Without being dependent on any theory, each low GI rice noodle modifier of the present application can inhibit the activity of α-amylase and hinder starch digestion through physical and chemical interactions and steric hindrance effects, to achieve a low GI effect. Specifically, the functional groups such as hydroxyl groups and carboxyl groups on the surface of the nanosized parenchyma cell wall in each low GI rice noodle modifier can directly adsorb α-amylase molecules through electrostatic interactions and hydrogen bonds, resulting in the enzyme active center being shielded or the conformation being changed. In addition to the inhibition of amylase molecules, the three-dimensional network structure formed by the nanosized parenchyma cell wall in the starch matrix can physically block the contact between α-amylase and starch molecules, significantly reducing the enzymatic efficiency. In addition, the nanosized parenchyma cell wall can also affect the gelatinization and retrogradation properties of starch by preferentially binding to amylose, further reducing the exposure of enzymatic sites. These synergistic effects ultimately result in a significant reduction in the rate and extent of starch digestion. In particular, the nanosized parenchyma cell wall of the present application may, due to the retention of part of the natural structure of the cell wall and the specific morphology, have a better effect on inhibiting amylase than conventional dietary fibers.

[0140] Comparative Example 1

[0141] The rice noodles can be prepared by extruding rice flour. First, 64 g of rice flour is added to 36 g of water and mixed uniformly, then kneaded into a ball, and then repeatedly pressed using a dough machine or a rolling pin, and then shaped into a strip to obtain the blank group rice noodle product.

[0142] The porcine pancreatic amylase is stirred at room temperature, and after uniform stirring, the mixture is allowed to stand at room temperature for 20 min to obtain a uniformly mixed blank group mixed solution system.

[0143] Figure 2 The ultraviolet spectrum of the blank group mixed system measured using the ultraviolet visible near-infrared spectrophotometer SOLID 3700 is shown.

[0144] Figure 3 The fluorescence spectrum of the blank group mixed system measured using the X-ray fluorescence spectrometer XRF-1800 is shown.

[0145] Gelatinization was performed using water mixed with starch.

[0146] Figure 4 The contents of rapidly digestible starch, slowly digestible starch and resistant starch of the blank group mixed system measured using an ST-360 microplate reader are shown.

[0147] Figure 5 The broken strand rate, water boiling loss rate and water absorption rate data of the rice noodles obtained by testing the blank group rice noodles without adding 1% of the nanoized parenchyma cell wall mass concentration of the low GI rice noodle modifier are shown.

[0148] As can be seen by comparing the experimental group and the blank group, the nanoized bamboo leaf cell wall of the application can reduce the amylase activity, and after adding the nanoized parenchyma cell wall, the low GI effect is better, and the broken strand rate and the water boiling loss rate are unexpectedly reduced compared with the rice noodles without adding.

[0149] In addition, the freshly prepared rice noodles of the experimental group and the blank group were placed in boiling water, and immediately after floating, 10 subjects were asked to cover their eyes to taste and evaluate the smoothness difference of the rice noodles of the experimental group and the blank group. The results show that the experimental group is not worse than the blank group.

[0150] As can be seen, the nanoized parenchyma cell wall obtained by the application added to the starch verifies that the material has the effect of inhibiting the increase of GI through multiple mechanisms, so it will have a broad application prospect in the related field of low GI food, etc. The nanoized cell wall extracted from natural plants added to the rice noodles of the application has the comprehensive excellent effect of reducing the glycemic index, improving the taste, reducing the broken strand rate and reducing the water boiling loss rate, etc. in addition to obtaining the low GI rice noodle product. The product has significant advantages and broad application prospects. The preparation method can obtain the required nanoized parenchyma cell wall simply, non-toxicly, efficiently and environmentally friendly, and the anhydrous ethanol treatment improves the preparation effect.

[0151] The above specific implementation and embodiment description is only used to help understand the method of the application and its core idea. It should be noted that for those skilled in the art, without departing from the principles and spirit of the application, some improvements and modifications can be made to the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A type of rice noodle with low GI properties, characterized in that, The rice noodles comprise: Rice noodles; Nanoscale thin-walled cell walls, extracted from bamboo husk, are edible, one-dimensional, with a lateral dimension below 100 nm and a longitudinal dimension above 1 μm; and water, The mass content of the nano-sized thin-walled cell wall in the rice noodles is between 0.1% and 1.5%.

2. The rice noodles according to claim 1, characterized in that, The rice noodles comprise a mixture of a dispersion of the nano-thin-walled cell wall in water and rice flour, wherein the mass ratio of the dispersion to the rice flour is in the range of 1:1 to 1:2, and the mass concentration of the nano-thin-walled cell wall in the dispersion is 0.3% to 3%, preferably 0.4% to 2.5%, and more preferably 0.5% to 2%.

3. The rice noodles according to claim 1, characterized in that, The total mass content of dietary fiber in the rice noodles is between 0.1% and 1.5%.

4. The rice noodles according to claim 1, characterized in that, The rice noodles contain the following components by weight percentage: The nano-sized thin-walled cell wall comprises 0.1% to 1.5% of the aforementioned cell wall. 35% to 60% rice flour, 35% to 55% water.

5. The rice noodles according to claim 1, characterized in that, The rice noodles also contain the remainder of a mixture of soy protein and corn starch.

6. A method for preparing rice noodles according to claim 1, characterized in that, The preparation method includes: The nano-sized thin-walled cell walls, rice flour, and water are uniformly mixed and shaped into rice noodles. The nano-sized thin-walled cell wall is prepared through the following steps: A) Add the bamboo yellow of natural bamboo 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.

7. The use of nano-sized thin-walled cell walls as a low-GI rice noodle improver, characterized in that, The nano-sized thin-walled cell wall is extracted from bamboo shavings and is edible. 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.

8. A low-GI rice noodle improver, characterized in that, The low-GI rice noodle improver contains nano-thin-walled cell walls extracted from bamboo husks. These nano-thin-walled cell walls are edible and have one-dimensional characteristics, with a lateral dimension of less than 100 nm and a longitudinal dimension of more than 1 μm.

9. The low-GI rice noodle improver according to claim 8, characterized in that, The low-GI rice noodle improver is a dispersion of the nano-sized thin-walled cell wall in water at a mass concentration of 0.3% to 3%, preferably 0.4% to 2.5%, more preferably 0.5% to 2%.

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