Food-grade method for extracting edible nano thin-walled cell walls from bamboo wood and application of food-grade method

Abstract

The invention provides a food-grade method for extracting an edible nanocrystallization thin-wall cell wall from bamboo wood and application of the food-grade method, and the food-grade method comprises the following steps: carrying out thermal stripping treatment on a bamboo wood raw material through food-grade absolute ethyl alcohol, and then carrying out oxidation bleaching treatment by using a mixture aqueous solution of food-grade hydrogen peroxide and glacial acetic acid, and finally performing nanocrystallization refining, thereby obtaining the required edible nanocrystallized thin-walled cell wall, and the edible nanocrystallized thin-walled cell wall can be used as a dysphagia adjuvant or a fluid food thickening agent. The edible nanocrystallization thin-wall cell wall provided by the invention can be used for reducing the glycemic index (GI) of fluid food, increasing the viscosity and enhancing the stability of the fluid food, so that the fluid food can stably have a relatively high viscosity characteristic under different pH and temperature conditions, and the texture and taste of the fluid food can be effectively improved.

Description

Technical Field

[0001] This invention relates to a food-grade method for extracting edible nano-sized thin-walled cell walls from bamboo and its application as a swallowing aid or food thickener. 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 a major structural component of plant cell walls. As a renewable carbon source, it shows broad application prospects in the energy, materials, and chemical industries. However, existing cellulose extraction or preparation technologies often employ harmful chemical reagents such as strong acids and strong oxidants for stripping, posing environmental pollution risks, and particularly hindering its safe and sufficient application in the food industry. Furthermore, dysphagia aids are food or pharmaceutical additives specifically designed for patients with swallowing difficulties, typically possessing thickening, lubricating, or nutritional fortification functions.

[0003] Furthermore, bamboo is characterized by its rapid growth and renewability. As a superior renewable biomass resource in my country, it is rich in thin-walled cell tissue, making the development of deep processing technology for bamboo and its application in the food industry of great significance. Summary of the Invention

[0004] In view of this, one object of the present invention is to provide a simple, efficient, and low-energy-consumption food-grade method for extracting nano-sized thin-walled cell walls from natural bamboo using food-grade reagents. Another object of the present invention is to use the nano-sized thin-walled cell walls extracted by the above method as a swallowing disorder aid or a food thickener.

[0005] In one aspect, the present invention provides a food-grade method for extracting edible nano-sized thin-walled cell walls from bamboo, the food-grade method comprising: adding natural bamboo to food-grade anhydrous ethanol and performing a thermal peeling treatment at a temperature of 60-80°C; adding the thermally peeled bamboo material to an aqueous solution of a mixture of food-grade hydrogen peroxide and food-grade glacial acetic acid and performing an oxidative bleaching treatment at a temperature of 60-80°C; and refining the oxidatively bleached bamboo material into nano-sized cells to obtain edible nano-sized thin-walled cell walls, wherein the obtained edible nano-sized thin-walled cell walls have at least one of the following properties: (a) the edible nano-sized thin-walled cell walls have a transverse dimension of 5-100 nm, a longitudinal dimension of 0.5-10 μm, and a longitudinal dimension to transverse dimension ratio of 20-400; and (b) the cellulose in the edible nano-sized thin-walled cell walls has a crystallinity of at least 60%.

[0006] In a preferred embodiment, the natural bamboo material is bamboo leaves, bamboo branches, internodes of bamboo stems, or a combination thereof, and is pretreated by soaking in water multiple times before being subjected to heat peeling.

[0007] In a preferred embodiment, the mass ratio of the natural bamboo to the food-grade anhydrous ethanol is 1:3 to 1:15.

[0008] In a preferred embodiment, the mass ratio of the natural bamboo to food-grade hydrogen peroxide is 1:1 to 1:10.

[0009] In a preferred embodiment, the mass ratio of the natural bamboo to food-grade glacial acetic acid is 1:1 to 1:10.

[0010] In a preferred embodiment, the nano-refining process includes breaking down the cell walls of the oxidized and bleached bamboo material by crushing with a cell wall breaker, ultrasonic treatment, crushing, grinding, or a combination thereof, and then homogenizing the cell wall-broken bamboo material by micro-jet homogenization or high-pressure homogenization.

[0011] In another aspect, the present invention provides the application of edible nano-sized thin-walled cell walls obtained by the above-described food-grade method as a swallowing disorder aid or a food thickener.

[0012] In a preferred embodiment, the swallowing disorder aid or food thickener is a dispersion of the edible nano-thin-walled cell wall with a mass concentration of 0.1-3%.

[0013] In a preferred embodiment, the dysphagia aid is used by adding it to a liquid diet for patients with dysphagia, wherein the dysphagia aid is added in an amount of 0.1 to 1.0% by weight based on the weight of the liquid diet.

[0014] In a preferred embodiment, the food thickener is used by adding it to a liquid food that requires thickening.

[0015] In a preferred embodiment, the dysphagia aid or food thickener is stable over a period of 5 to 14 days under at least one of the following conditions: (1) at a temperature of 0°C to 40°C; (2) in a medium with a pH of 1 to 11; and (3) at a shear rate of 2000 to 6000 rpm.

[0016] In a preferred embodiment, the liquid food includes dairy products, condiments, soups, juices, beverages, or combinations thereof in fluid form.

[0017] This invention uses natural bamboo as raw material and food-grade reagents to extract nano-sized thin-walled cell walls from bamboo through a simple, efficient, and low-energy food-grade method. The edible nano-sized thin-walled cell walls obtained in this way can be used as a swallowing disorder aid or a thickener for liquid foods.

[0018] Furthermore, by utilizing the edible nano-thin-walled cell wall provided by this invention, the glycemic index (GI) of liquid foods can be reduced, their viscosity increased, and their stability enhanced, thereby enabling them to maintain high viscosity characteristics under different pH and temperature conditions, which can effectively improve the texture and mouthfeel of liquid foods. Attached Figure Description

[0019] Figure 1 A digital photograph of bamboo leaves used as a natural bamboo material according to Example 1 is shown.

[0020] Figure 2 A scanning electron microscope image of bamboo leaves used as a natural bamboo material according to Example 1 is shown.

[0021] Figure 3 A digital photograph of a 0.5% by mass aqueous dispersion of bamboo nano-thin-walled cell walls obtained according to Example 1 is shown.

[0022] Figure 4 A scanning electron microscope image of the bamboo nanostructured thin-walled cell wall obtained according to Example 1 is shown.

[0023] Figure 5 A bar chart showing the percentage of cellulose, hemicellulose and lignin in bamboo leaves used as natural bamboo raw material according to Example 1 before and after peeling treatment is shown.

[0024] Figure 6 An X-ray diffraction pattern of the bamboo nano-thin-walled cell wall obtained according to Example 1 is shown.

[0025] Figure 7 Viscosity curves are shown for the addition of a 0.5% by mass aqueous dispersion of bamboo nano-thin-walled cell wall obtained according to Example 1 to apple juice, coconut juice, and soda water according to Application Examples 1-3.

[0026] Figure 8 Storage modulus curves are shown for apple juice, coconut juice, and soda water after adding 0.5% by mass of an aqueous dispersion of bamboo nano-thin-walled cell wall obtained according to Example 1.

[0027] Figure 9 The loss modulus curves are shown for apple juice, coconut juice, and soda water after adding a 0.5% by mass aqueous dispersion of bamboo nano-thin-walled cell wall obtained according to Example 1.

[0028] Figure 10 Viscosity curves are shown for the addition of 0.5% by mass aqueous dispersions of corn starch to apple juice, coconut juice, and soda water according to Comparative Examples 1-3.

[0029] Figure 11 Storage modulus curves are shown for the addition of 0.5% by mass aqueous dispersions of corn starch to apple juice, coconut juice, and soda water according to Comparative Examples 1-3.

[0030] Figure 12 The loss modulus curves are shown for the addition of 0.5% by mass aqueous dispersions of corn starch to apple juice, coconut juice, and soda water according to Comparative Examples 1-3.

[0031] Figure 13 Viscosity curves are shown for aqueous dispersions of 0.5% by mass of pectin added to apple juice, coconut juice, and soda water, according to Comparative Examples 4-6.

[0032] Figure 14 Storage modulus curves are shown for 0.5% by mass aqueous dispersions of pectin added to apple juice, coconut juice, and soda water according to Comparative Examples 4-6.

[0033] Figure 15 The loss modulus curves are shown for 0.5% by mass aqueous dispersions of pectin added to apple juice, coconut juice, and soda water according to Comparative Examples 4-6. Detailed Implementation

[0034] To fully utilize bamboo resources, especially for applications in the food industry, this invention provides a food-grade method for extracting edible nano-sized thin-walled cell walls from bamboo. The method includes: thermally peeling natural bamboo with food-grade anhydrous ethanol, followed by oxidative bleaching with a mixture of food-grade hydrogen peroxide and glacial acetic acid, and finally nano-refining to obtain the desired edible nano-sized thin-walled cell walls. Furthermore, the extracted edible nano-sized thin-walled cell walls can be used as a swallowing aid or a thickener for fluid foods.

[0035] More specifically, the food-grade method for extracting edible nano-sized thin-walled cell walls from bamboo according to the present invention includes: adding natural bamboo to food-grade anhydrous ethanol and performing a thermal peeling treatment at a temperature of 60-80°C; adding the thermally peeled bamboo material to a mixed solution of food-grade hydrogen peroxide and food-grade glacial acetic acid and performing an oxidative bleaching treatment at a temperature of 60-80°C; and refining the oxidatively bleached bamboo material into nano-sized cells to obtain edible nano-sized thin-walled cell walls.

[0036] In this invention, the term "nanosized thin-walled cell wall" refers to a thin-walled cell wall as a fibrous material whose one dimension is in the nanoscale range. Preferably, the diameter of the bamboo cellulose nanofibers obtained by this invention is less than 100 nm.

[0037] In this invention, there are no particular restrictions on the source of the natural bamboo used. It can come from bamboo plants of different regions, varieties, years, and heights above the ground, preferably 3-year-old moso bamboo. More preferably, the natural bamboo used can be bamboo leaves, bamboo branches, internodes of bamboo stems, or a combination thereof.

[0038] In this invention, preferably, the bamboo raw material is soaked in water (e.g., deionized water) multiple times for surface pretreatment before thermal stripping. For example, the bamboo raw material is soaked in deionized water for 12-48 hours, then the deionized water is replaced and the material is soaked for another 12-48 hours. This operation can be repeated once or multiple times until at least most of the impurities such as salt on the surface of the bamboo are removed.

[0039] In this invention, the term "food grade" refers to a quality grade suitable for human or animal use, and is used interchangeably with the term "edible." Further, the food-grade method mentioned in this invention refers to a method suitable for manufacturing food or food products or intermediate products that are edible for humans or animals. In other words, in the method of this invention, the raw material used is natural bamboo or a portion thereof, no toxic or harmful solvents are added during the extraction process, resulting in minimal environmental pollution, low energy consumption, a simple and efficient stripping process, and the obtained nano-sized thin-walled cell walls possess food safety characteristics. Accordingly, the food-grade anhydrous ethanol used in this invention refers to anhydrous ethanol reagent that can be ingested by humans or animals without producing significant toxic side effects, and can be commercially available, for example, from Guangzhou Kangben Biotechnology Co., Ltd. Similarly, the food-grade glacial acetic acid used in this invention refers to glacial acetic acid that can be ingested by humans or animals without producing significant toxic side effects, and can be commercially available, for example, from Guangzhou Kangben Biotechnology Co., Ltd. Furthermore, the food-grade hydrogen peroxide used in this invention refers to hydrogen peroxide reagent that meets the quality requirements for food manufacturing, and can be commercially available, for example, from Guangzhou Kangben Biotechnology Co., Ltd.

[0040] In this invention, preferably, the temperature for thermal stripping treatment can be 75-80°C. There is no particular limitation on the duration of the thermal stripping treatment; for example, it can be 12-48 hours, preferably 24-48 hours, and more preferably 36-48 hours. Without being limited by any theory, it is believed that thermal stripping treatment using food-grade anhydrous ethanol at a temperature of 60-80°C can promote the exposure or precipitation of cellulose, hemicellulose, and / or lignin in natural bamboo, thus facilitating subsequent oxidative bleaching treatment.

[0041] In this invention, preferably, the mass ratio of natural bamboo to food-grade anhydrous ethanol is 1:3 to 1:15, more preferably 1:5 to 1:10. The inventors have discovered that within this mass ratio range, the exposure or precipitation of cellulose, hemicellulose, and / or lignin in natural bamboo can be achieved more efficiently and rapidly. Furthermore, within this mass ratio range, the method of this invention offers higher cost-effectiveness and efficiency, and more thorough stripping.

[0042] In this invention, there is no particular limitation on the bleaching treatment time; for example, it can be 12-48 hours, preferably 24-48 hours, and more preferably 36-48 hours. Without being limited by any theory, it is believed that by treating bamboo raw materials (especially exposed cellulose, hemicellulose, and / or lignin) at a temperature of 60-80°C using a mixture of food-grade hydrogen peroxide and food-grade glacial acetic acid, the vascular bundles and basic parenchyma tissue in the bamboo can be deconstructed, thereby completing the bleaching of the bamboo. More specifically, during the oxidation process, the lignin phenylpropane units in the intercellular spaces of the bamboo can be cleaved, generating free aromatic small molecules, allowing the bamboo cell tissue to obtain nano-sized thin-walled cell walls through subsequent nano-refining.

[0043] In this invention, preferably, the mass ratio of the natural bamboo material used to food-grade hydrogen peroxide (usually a certain concentration, such as a 20% by mass aqueous solution) can be 1:1 to 1:10, more preferably 1:3 to 1:5. This invention has found that within such a ratio range, the desired oxidation can be achieved relatively quickly.

[0044] In this invention, preferably, the mass ratio of natural bamboo to food-grade glacial acetic acid is 1:1 to 1:10, more preferably 1:2 to 1:6. This invention has found that under such ratio conditions, sufficient acidity is guaranteed during the oxidation process, thereby promoting its rapid completion. In this invention, the organic acid is not actually consumed during the oxidation process; it can be considered a catalyst for peroxide oxidation. Therefore, it can be recovered and reused after the reaction, for example, through distillation, thus reducing waste emissions, achieving environmental protection, and lowering production costs.

[0045] In this invention, there are no particular limitations on the form of the food-grade hydrogen peroxide used; for example, it can be pure hydrogen peroxide or an aqueous solution of hydrogen peroxide. For instance, the food-grade hydrogen peroxide used in this invention can be an aqueous solution with a mass concentration of 10-40%, preferably 15-30%. Similarly, there are no particular limitations on the form of the food-grade glacial acetic acid used; for example, it can be pure glacial acetic acid or an aqueous solution of glacial acetic acid. For instance, the food-grade glacial acetic acid used in this invention can be an aqueous solution of glacial acetic acid with a mass concentration of 30-90%, preferably 60-80%. Preferably, when hydrogen peroxide and glacial acetic acid are used in aqueous solutions of the above-mentioned mass concentrations, their volume ratio in the mixed solution is preferably 1:3 to 1:15. With such a mass ratio, the acidic environment can be maintained more effectively during the oxidative bleaching process, while ensuring that the oxidative bleaching process is completed quickly.

[0046] In this invention, preferably, after the bleaching process is completed, the oxidized bamboo can be washed multiple times with clean water to remove organic acids and hydrogen peroxide. More preferably, the oxidized bamboo can be soaked in clean water multiple times until the pH is neutral before proceeding to the next step.

[0047] Next, the bleached bamboo is subjected to nano-refining. Preferably, in the method of the present invention, nano-refining may include, but is not limited to, using a cell wall crusher, ultrasonic treatment, crushing, grinding or pulverizing, or a combination thereof well known in the art to break down the cell walls of the oxidized and bleached bamboo material, and then subjecting the cell wall-broken bamboo material to micro-jet homogenization or high-pressure homogenization.

[0048] In this invention, the product obtained after nano-refining can be an aqueous dispersion with a mass concentration of 0.5-2%. The inventors have discovered that the edible nano-sized thin-walled cell walls obtained through this nano-refining process possess characteristics such as high crystallinity, high aspect ratio, and excellent mechanical and thermal stability, making them promising for broad applications in the food industry.

[0049] In this invention, preferably, the edible nano-thin-walled cell wall extracted by the above method can have at least one of the following properties: (a) the edible nano-thin-walled cell wall has a transverse dimension of 5-100 nm, a longitudinal dimension of 0.5-10 μm, and a ratio of longitudinal dimension to transverse dimension of 20-400; and (b) the cellulose in the edible nano-thin-walled cell wall has a crystallinity of at least 60%.

[0050] In this invention, the dimensions (including transverse and longitudinal dimensions) of the extracted edible nano-sized thin-walled cell walls can be measured using an atomic force microscope. For example, the dimensions (including transverse and longitudinal dimensions) of the extracted nano-sized bamboo thin-walled cell wall product can be measured, for example, by dropping a certain amount of the extracted nano-sized bamboo thin-walled cell wall aqueous dispersion onto a clean, flat mica sheet and using, for example, a Bruker Dimension Icon atomic force microscope.

[0051] In this invention, the cellulose, hemicellulose, and lignin content of the extracted nano-sized bamboo thin-walled cell wall product is obtained by the Panthen washing method. As mentioned herein, the Panthen washing method is a commonly used and standardized method in the industry for determining the content of these three elements. The determination process involves washing away non-soluble substances using a neutral detergent, then washing away hemicellulose using an acidic detergent, followed by acid soaking to remove cellulose, and finally burning away the remaining ash from the lignin. The cellulose, hemicellulose, and lignin content are then calculated based on the mass loss and mass residue at each step. For example, the specific method can be found in the following reference: Van Soest, PJ, Robertson, JB, Lewis, BA, 1991. Methods for dietary fiber, neutral detergent fiber, and non-starch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74, 3583-3597.

[0052] In this invention, the scanning electron microscope images were taken using a Carl Zeiss Supra 40 scanning electron microscope. After the sample was dried, it was placed on a conductive adhesive and gold was vaporized for 40 seconds before being photographed.

[0053] In this invention, the crystallinity of the extracted edible nano-sized thin-walled cell wall can be obtained by performing powder XRD diffraction on the product and calculating it using the Segal method. For example, the XRD diffraction image of the extracted nano-sized bamboo thin-walled cell wall product was obtained by placing approximately 10 mL of the resulting aqueous dispersion (mass concentration of 0.5~2% by mass) on a plate and drying it completely, and then measuring it using a Rigaku SmartLab X-ray diffractometer. Its crystallinity can be obtained by dividing the difference between the intensity of the maximum crystallization peak near 22.8° and the intensity of the lowest peak near 18° in the XRD pattern by the intensity of the maximum crystallization peak.

[0054] In this invention, the extracted nano-sized bamboo thin-walled cell wall product can be dispersed in water to form an aqueous dispersion. The mass concentration or solid content of the aqueous dispersion can be detected by taking a certain amount of the dispersion after stirring or shaking to uniformly disperse it, and recording its wet weight. Then, the dispersion is dried in an 80°C oven and its dry weight is recorded. The solid content mass fraction can then be calculated by "dry weight / wet weight × 100%".

[0055] In this invention, depending on the need, the aqueous dispersions of nano-sized bamboo thin-walled cell wall products of different concentrations can be concentrated by heating or diluted with a certain amount of water and then uniformly dispersed.

[0056] In this invention, the obtained nano-sized bamboo thin-walled cell wall product has a typical nano-one-dimensional structure, and its aqueous dispersion has a condensed viscosity and is stably dispersed.

[0057] In this invention, the edible nano-sized thin-walled cell walls obtained by the above-described food-grade method can be used as swallowing dysphagia aids or food thickeners, wherein the edible nano-sized thin-walled cell walls used as swallowing dysphagia aids are added to liquid foods intended for patients with swallowing disorders. As used herein, the term "swallowing dysphagia aid" is used in its usual sense; a swallowing dysphagia aid is a food or pharmaceutical additive specifically designed for patients with swallowing difficulties, typically possessing thickening, lubricating, or nutritional fortifying functions. It slows the flow rate and reduces the risk of aspiration by adjusting the texture of food, or improves the smoothness of food by adding special ingredients. The core purpose of swallowing aid thickening is to reduce the risk of liquid aspiration into the trachea, while allowing the liquid to remain in the mouth and esophagus longer, giving individuals with weaker swallowing functions sufficient time to complete the swallowing action. Simply put, thin liquids like water and juice flow quickly. When swallowing function declines (such as in the elderly or stroke patients), the liquid can easily slip into the trachea before being swallowed, causing choking, pneumonia, or even suffocation. Thicker liquids (similar in consistency to rice water or yogurt) flow more slowly, better matching the rhythm of tongue movements and descending smoothly down the esophagus, significantly reducing the risk.

[0058] In this invention, the edible nano-thin-walled cell wall obtained by the above-described food-grade method can also be used as a food thickener, wherein the edible nano-thin-walled cell wall is added to a fluid food that requires thickening.

[0059] In this invention, preferably, the dysphagia aid or food thickener can be added in an amount of 0.1 to 1.0% by weight, based on the weight of the liquid food.

[0060] In this invention, preferably, the swallowing disorder aid or food thickener can be used in the form of a dispersion formed by dispersing edible nano-sized thin-walled cell walls in water. In this invention, preferably, the mass concentration of the dispersion is 0.1-3%, more preferably 0.3-2.5%, and even more preferably 0.5-2%.

[0061] In this invention, preferably, the dysphagia aid or food thickener is stable over a period of 5 to 14 days under at least one of the following conditions: (1) at a temperature of 0°C to 40°C; (2) in a medium with a pH of 1 to 11; and (3) at a shear rate of 2000 to 6000 rpm. The inventors have found that dysphagia aids or food thickeners stable under one or more of the above conditions are more suitable for daily storage and use, applicable to various scenarios, and have better viscosity and thickening effect. Furthermore, by using such dysphagia aids or food thickeners, a dense network structure is formed between them and liquid foods, resulting in good overall stability of the food.

[0062] In this invention, preferably, there are no particular limitations on the form of liquid food, such as including but not limited to dairy products, condiments, soups, juices, beverages or combinations thereof in liquid form.

[0063] In this invention, the effect of using it as a food thickener can be determined, for example, by the following method: First, edible nano-sized thin-walled cell walls are dispersed in water to form a dispersion with a mass concentration of 0.1-3%; then, the dispersion is added to a food beverage or fruit juice, wherein the two can be mixed at a mass ratio of 10:1-50:1, preferably 10:1-25:1, more preferably 10:1-20:1, and uniformly mixed and dispersed (e.g., at 1500-3000 r / min) by mechanical means such as a magnetic stirrer, ultrasonic stirrer, PTFE stirrer, and cell disruptor (preferably a magnetic stirrer and cell disruptor, more preferably a cell disruptor). -1 Stir for 2-15 minutes, then let stand in a freezer for a period of time, such as 30-60 minutes, preferably 10-15 minutes; finally, take a certain amount of the resulting mixture and place it in, for example, a glass beaker for rheological property testing. For example, the viscosity measurement method can be selected according to the characteristics of the mixed solution being tested: a rheometer is used, such as the TA Instruments Waters HR20; a parallel plate with a diameter of 60 mm is used, and the shear rate is measured from 0.01 to 100 s⁻¹ at 8°C. -1 The change in solution viscosity and the rotation speed (1-100 rad / s) -1 Changes in the storage modulus and loss modulus of the solution.

[0064] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, these examples are only for illustrating the specific implementation process of the present invention and are not intended to limit the scope of the claims.

[0065] Example

[0066] Preparation Example 1

[0067] In a 5L water tank (Jiumuwang water tank; 5MM304), 1000g of bamboo leaves (purchased from Taobao Xinmengyuan Flower Shop) were repeatedly soaked and washed with a large amount of deionized water to remove at least most of the salt and other impurities on the surface.

[0068] Next, in a reaction vessel equipped with a water bath for heating, the cleaned bamboo leaves were added to a food-grade anhydrous ethanol solution with a mass concentration of 99.5% (Guangzhou Kangben Biotechnology Co., Ltd.) and subjected to heat peeling treatment at 80°C for 12 hours.

[0069] Then, in a 5L beaker, the bamboo leaves after heat peeling were repeatedly washed with water until the pH was neutral. They were then soaked in a mixed solution containing 1000 g of food-grade 30% hydrogen peroxide aqueous solution (purchased from Hangzhou Mingxin Hydrogen Peroxide Co., Ltd.) and 1000 g of food-grade glacial acetic acid (purchased from Shandong Jiayu Chemical Co., Ltd.) and subjected to oxidative bleaching treatment at 60℃ for 24 hours until the bamboo leaves were observed to be completely faded, thus completing the oxidative bleaching treatment.

[0070] Subsequently, the bamboo leaves, after oxidative bleaching, were soaked in fresh water repeatedly until the surface pH was neutral, and then added to a pulper (Joyoung pulper model L18-Y66, speed 8000 rad / min) for 1 hour. The resulting pulp was then homogenized at least twice using a 2.2kW high-pressure homogenizer (Antos Nanotechnology (Suzhou) Co., Ltd., AH-BASIC 30) at 800 bar. After adjusting the amount of dispersion medium appropriately, an aqueous dispersion of nano-sized bamboo thin-walled cell wall product with a mass concentration or solid content of approximately 0.5% was obtained. This product was then stored directly as the obtained aqueous dispersion.

[0071] Figure 1 A digital photograph (taken with a Huawei P30 phone) of bamboo leaves used as a natural bamboo raw material according to Example 1 is shown. Figure 2 A scanning electron microscope image of the bamboo leaf is shown. Figure 1 As shown, natural bamboo leaves are thin and green or bluish-green before treatment, and from Figure 2 It can be seen that natural bamboo leaves have a roughly regular tissue structure.

[0072] Figure 3A digital photograph is shown of a 0.5% by mass aqueous dispersion of bamboo nano-thin-walled cell walls obtained according to Example 1, and is produced by... Figure 3 It can be seen that the obtained product is a homogeneous slurry and does not settle. Furthermore, after stability tests at temperatures of 0℃ to 40℃, in media with pH values ​​of 1 to 11, and / or at shear rates of 2000 to 6000 rpm, the obtained aqueous dispersion product can remain a homogeneous slurry without settling for a period of 5 to 14 days, which means it is stable.

[0073] Figure 4 A scanning electron microscope image of the bamboo nanostructured thin-walled cell wall obtained according to Example 1 is shown. From Figure 4 and Figure 2 The comparison shows that the bamboo nano-thin-walled cell wall product obtained after the treatment of this invention is significantly different from the raw bamboo leaves in terms of tissue structure.

[0074] Figure 5 A bar chart showing the percentage of cellulose, hemicellulose, and lignin in bamboo leaves used as natural bamboo raw material according to Example 1 before and after peeling treatment is presented. Figure 5 It can be seen that, compared with before the stripping treatment, the proportion of cellulose increased, the proportion of hemicellulose decreased, and the proportion of lignin decreased significantly after the stripping treatment.

[0075] Figure 6 The X-ray diffraction pattern of the bamboo nanostructured thin-walled cell wall obtained according to Example 1 is shown using a PANalytical X'pertPRO MRD X-ray diffractometer. From Figure 6 It can be seen that after nano-refining, the characteristic peaks of the obtained nanocellulose are more obvious, and according to this... Figure 6 The crystallinity of the nano-sized bamboo thin-walled cell wall product was calculated using the Segal method to be high, approximately 71.2%. This crystallinity was obtained by dividing the difference between the maximum crystallization peak intensity near 22.8° and the minimum peak intensity near 18° in the XRD pattern by the maximum crystallization peak intensity.

[0076] The nano-sized bamboo thin-walled cell walls obtained according to Example 1 were observed and detected using a dimensionicon atomic force microscope, for example, from Bruker. The lateral dimensions of the obtained products were approximately 10-20 nm and the length was between 1 μm and 10 μm.

[0077] Preparation Example 2

[0078] The preparation and testing procedures were the same as in Preparation Example 1, except that the duration of the thermal exfoliation treatment in the food-grade anhydrous ethanol solution was changed from 12 h to 24 h, and the amount of dispersion medium was adjusted appropriately to obtain an aqueous dispersion of the nano-sized bamboo thin-walled cell wall product with a mass concentration or solid content of about 1.0%.

[0079] Moreover, similar results to those obtained in Preparation Example 1 were obtained after testing. In particular, the obtained aqueous dispersion was stable, the crystallinity of the obtained nano-sized bamboo thin-walled cell wall product was about 70.8%, and the transverse size of the obtained product was basically about 8~18 nm and the length was between 1 μm and 8 μm.

[0080] Preparation Example 3

[0081] The preparation and testing procedures were the same as in Preparation Example 1, except that the bamboo leaves used in Preparation Example 1 were replaced with bamboo yellow blocks (the inner layer of bamboo stems, which are usually light yellow or milky white) cut from freshly cut natural moso bamboo (obtained from Huoshan, Anhui), and an aqueous dispersion of nano-sized bamboo thin-walled cell wall product with a mass concentration or solid content of about 1.5% was obtained by appropriately adjusting the amount of dispersion medium.

[0082] Moreover, similar results to those obtained in Preparation Example 1 were obtained after testing. In particular, the obtained aqueous dispersion was stable, the crystallinity of the obtained nano-sized bamboo thin-walled cell wall product was about 70.2%, and the lateral size of the obtained product was basically about 11~19 nm and the length was between 1 μm and 9 μm.

[0083] Preparation Example 4

[0084] The preparation and testing procedures were the same as in Preparation Example 1, except that the temperature of the heat-peeling treatment in the food-grade anhydrous ethanol solution was changed from 80°C to 70°C, and the amount of dispersion medium was adjusted appropriately to obtain an aqueous dispersion of nano-sized bamboo thin-walled cell wall product with a mass concentration or solid content of about 2.0%.

[0085] Moreover, similar results to those obtained in Preparation Example 1 were obtained after testing. In particular, the obtained aqueous dispersion was stable, the crystallinity of the obtained nano-sized bamboo thin-walled cell wall product was about 71.0%, and the transverse size of the obtained product was basically about 9~20 nm and the length was between 2 μm and 12 μm.

[0086] Preparation Example 5

[0087] The preparation and testing procedures were the same as in Preparation Example 1, except that the temperature of the oxidative bleaching treatment in the mixed solution of hydrogen peroxide aqueous solution and food-grade glacial acetic acid was changed from 60°C to 80°C, and the amount of dispersion medium was adjusted appropriately to obtain an aqueous dispersion of nano-sized bamboo thin-walled cell wall product with a mass concentration or solid content of about 1.0%.

[0088] Moreover, similar results to those obtained in Preparation Example 1 were obtained after testing. In particular, the obtained aqueous dispersion was stable, the crystallinity of the obtained nano-sized bamboo thin-walled cell wall product was about 71.3%, and the lateral size of the obtained product was basically about 1~7 nm and the length was between 1 μm and 8 μm.

[0089] Preparation Example 6

[0090] The preparation and testing procedures were the same as in Preparation Example 1, except that the oxidative bleaching treatment time in the mixed solution of hydrogen peroxide aqueous solution and food-grade glacial acetic acid was changed from 24 h to 48 h. Based on the tests, similar results to those in Preparation Example 1 were obtained. In particular, the crystallinity of the obtained nano-sized bamboo thin-walled cell wall product was approximately 71.8%, and the lateral dimensions of the obtained product were approximately 10–18 nm, with a length between 1 μm and 6 μm.

[0091] Application Example 1

[0092] In a 5L glass beaker equipped with a water bath, 100g of the 1.0% (w / w) nano-thin-walled cell wall aqueous dispersion obtained in Preparation Example 2 was mixed with 1000g of pure apple juice (obtained from Huiyuan Apple Juice), and the mixture was magnetically stirred at 60°C for 30 min to ensure uniform mixing.

[0093] Then, 10 g of the resulting homogeneous mixture solution was placed in a glass beaker, and its rheological properties were tested using a rheometer (TA Instruments Waters, HR20, USA). A parallel plate with a diameter of 60 mm was used, and the shear rate was measured from 0.01 to 100 s⁻¹ at 8°C. -1 The change in solution viscosity is shown in the results. Figure 7 Similarly, 10g of the obtained homogeneous mixture solution was placed in a glass beaker, and its rheological properties were tested using a rheometer (TA Instruments Waters Corporation, HR20, USA). A parallel plate with a diameter of 60 mm was used, and the changes in the storage modulus and loss modulus of the solution were measured at 8°C with an oscillation frequency of 0.1-100 Hz. The results are shown in […]. Figure 8 , Figure 9 middle.

[0094] Application Example 2

[0095] The application and testing procedures were the same as in the application example, except that the apple juice used was replaced with pure coconut juice (obtained from Coconut Palm brand coconut juice). Furthermore, the results of the tests on viscosity change, storage modulus, and loss modulus were displayed as follows: Figure 7-9 middle.

[0096] Application Example 3

[0097] The application and testing procedures were the same as in the application example, except that the apple juice used was replaced with soda water (obtained from Mingren Soda Water). Furthermore, the results of the tests on viscosity change, storage modulus, and loss modulus are shown below. Figure 7-9 middle.

[0098] from Figure 7 It can be seen that, after adding the nano-thin-walled cell wall aqueous dispersion product of the present invention, the viscosity of liquid foods such as apple juice, coconut milk, and soda water can be changed over a wide range based on the shear rate with a substantially similar trend, allowing the viscosity of liquid foods to be changed as needed using the product of the present invention; simultaneously, from Figure 8 and Figure 9 It can be seen that after adding the nano-thin-walled cell wall aqueous dispersion product of the present invention, the storage modulus and loss modulus of liquid foods such as apple juice, coconut juice and soda water can be increased with a substantially similar trend at different frequencies or rotation speeds. The larger the storage modulus and loss modulus, the stronger the elasticity and structural strength of the liquid food system. This makes the product of the present invention particularly suitable as a swallowing aid by adding it to liquid foods for patients with swallowing disorders, or suitable as a thickener by adding it directly to liquid foods that require thickening.

[0099] Application Comparison Example 1

[0100] The application and testing procedures were the same as in Application Example 1, except that the 1.0% (w / w) aqueous dispersion of nano-thin-walled cell walls was replaced with a 1.0% (w / w) aqueous dispersion of corn starch (purchased from a regular supermarket). Furthermore, the results of the tests on viscosity change, storage modulus, and loss modulus were shown in [the table / data]. Figure 10-12 middle.

[0101] Application Comparison Example 2

[0102] The application and testing procedures were the same as in Comparative Application 1, except that the apple juice used was replaced with pure coconut juice. Furthermore, the results of the tests on viscosity change, storage modulus, and loss modulus were shown in [the table / data]. Figure 10-12 middle.

[0103] Application Comparison Example 3

[0104] The application and testing procedures were the same as in Comparative Application 1, except that the apple juice used was replaced with soda water. Furthermore, the results of the tests on viscosity change, storage modulus, and loss modulus were displayed as follows: Figure 10-12 middle.

[0105] from Figure 10It can be seen that, although the addition of corn starch aqueous dispersion can change the viscosity of liquid foods such as apple juice, coconut milk, and soda water, the change in viscosity of these three liquid foods by the corn starch aqueous dispersion does not achieve the same substantially uniform trend as the product of this invention. The effect on the viscosity change of apple juice and soda water is significantly smaller, and the range of viscosity change is very small. Meanwhile, from... Figure 11 and Figure 12 It can be seen that after adding the corn starch dispersion, its effect on the storage modulus and loss modulus of liquid foods such as apple juice, coconut juice, and soda water does not show the same increasing trend as the product of this invention. On the contrary, it shows essentially no change or even a decrease in the storage modulus and loss modulus of apple juice and soda water, while showing a completely different effect of a sharp increase for coconut juice. This indicates that compared with the product of this invention, the corn starch aqueous dispersion is significantly less effective as a swallowing aid or thickener for liquid foods. Furthermore, due to the uncertainty in its effect on the viscosity, storage modulus, and loss modulus of liquid foods, this corn starch aqueous dispersion is not particularly suitable as a swallowing aid or thickener for liquid foods for patients with swallowing disorders.

[0106] Application Comparison Example 4

[0107] The application and testing procedures were the same as in Application Example 1, except that the 1.0% (w / w) aqueous dispersion of nano-sized thin-walled cell walls was replaced with a 1.0% (w / w) aqueous dispersion of pectin (purchased from a regular supermarket). Furthermore, the results of the tests on viscosity change, storage modulus, and loss modulus were shown in [the table / data]. Figure 13-15 middle.

[0108] Application Comparison Example 5

[0109] The application and testing procedures were the same as those in Comparative Application 4, except that the apple juice used was replaced with pure coconut juice. Furthermore, the results of the tests on viscosity change, storage modulus, and loss modulus were shown in [the table / data]. Figure 13-15 middle.

[0110] Application Comparison Example 6

[0111] The application and testing procedures were the same as those in Comparative Application 4, except that the apple juice used was replaced with soda water. Furthermore, the results of the tests on viscosity change, storage modulus, and loss modulus were displayed as follows: Figure 13-15 middle.

[0112] from Figure 13 It can be seen that the addition of pectin aqueous dispersion can change the viscosity of liquid foods such as apple juice, coconut milk, and soda water. However, compared with the product of this invention, the range of viscosity change is significantly smaller and the trend is different; at the same time, from Figure 14 and Figure 15 It can be seen that after adding the pectin dispersion, its effect on the storage modulus and loss modulus of liquid foods such as apple juice, coconut milk, and soda water does not show the same trend as the product of this invention. On the contrary, it shows little to no change or even a decrease in the storage modulus and loss modulus of apple juice, while it shows different effects of linear increase and sharp increase for coconut milk and soda water. This indicates that compared with the product of this invention, the pectin aqueous dispersion is less effective as a swallowing aid or thickener for liquid foods, and due to the uncertainty in its effect on the viscosity, storage modulus, and loss modulus of liquid foods, the pectin aqueous dispersion is not particularly suitable as a swallowing aid or thickener for liquid foods for patients with swallowing disorders.

[0113] Industrial applicability

[0114] This invention provides a food-grade method for extracting edible nano-sized thin-walled cell walls from bamboo. The resulting edible nano-sized thin-walled cell wall product can reduce the glycemic index (GI) of liquid foods, increase their viscosity, and enhance their stability, thereby enabling them to maintain high viscosity characteristics under different pH and temperature conditions and effectively improve the texture and mouthfeel of liquid foods.

[0115] 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 protection scope of the claims of the present invention.

Claims

1. A food-grade method for extracting edible nano-sized thin-walled cell walls from bamboo, characterized in that, The food-grade method includes: Natural bamboo is added to food-grade anhydrous ethanol and subjected to heat peeling treatment at a temperature of 60~80℃. The heat-peeled bamboo material was added to a mixed aqueous solution of food-grade hydrogen peroxide and food-grade glacial acetic acid and subjected to oxidative bleaching treatment at a temperature of 60-80°C; and Bamboo materials that have undergone oxidative bleaching are then refined into nano-sized cells to obtain edible nano-sized thin-walled cell walls. The edible nano-sized thin-walled cell walls obtained therefrom possess at least one of the following properties: (a) The edible nano-sized thin-walled cell wall has a transverse dimension of 5-100 nm, a longitudinal dimension of 0.5-10 μm, and a longitudinal dimension to transverse dimension ratio of 20-400; and (b) The cellulose in the edible nano-thin-walled cell wall has a crystallinity of at least 60%.

2. The food-grade method according to claim 1, characterized in that, The natural bamboo material is bamboo leaves, bamboo branches, internodes of bamboo stems or a combination thereof, and is pretreated by soaking in water multiple times before being subjected to heat peeling.

3. The food-grade method according to claim 1, characterized in that, The mass ratio of the natural bamboo to the food-grade anhydrous ethanol is 1:3 to 1:15, the mass ratio of the natural bamboo to the food-grade hydrogen peroxide is 1:1 to 1:10, and the mass ratio of the natural bamboo to the food-grade glacial acetic acid is 1:1 to 1:

10.

4. The food-grade method according to claim 1, characterized in that, The nano-refining process includes breaking down the cell walls of oxidized and bleached bamboo materials by crushing with a cell wall breaker, ultrasonic treatment, crushing, grinding, or a combination thereof, and then homogenizing the cell wall-broken bamboo materials by micro-jet flow or high pressure.

5. The use of edible nano-sized thin-walled cell walls obtained by the food-grade method according to any one of claims 1-4 as a swallowing disorder aid or a food thickener.

6. The application according to claim 5, characterized in that, The swallowing disorder aid or food thickener is a dispersion of the edible nano-thin-walled cell wall with a mass concentration of 0.1-3%.

7. The application according to claim 5, characterized in that, The swallowing dysphagia aid is used by adding it to a liquid diet for patients with swallowing dysphagia, wherein the swallowing dysphagia aid is added in an amount of 0.1 to 1.0% by weight based on the weight of the liquid diet.

8. The application according to claim 5, characterized in that, The food thickener is used by adding it to liquid foods that require thickening.

9. The application according to claim 6, characterized in that, The swallowing dysphagia aid or food thickener is stable over a period of 5 to 14 days under at least one of the following conditions: (1) At temperatures ranging from 0℃ to 40℃; (2) In a medium with a pH of 1–11; and (3) At a shear rate of 2000 to 6000 rpm.

10. The application according to claim 7 or 8, characterized in that, The liquid foods include dairy products, condiments, soups, juices, beverages, or combinations thereof in liquid form.

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