Application of cellulose nanofiber extracted from bean dregs as thickening agent

Abstract

The invention provides application of cellulose nanofibers extracted from bean dreg residues as a thickening agent, and particularly relates to application of the cellulose nanofibers extracted from the bean dreg residues as a beverage thickening agent in the food field. The bean dreg cellulose nanofiber disclosed by the invention is added into liquids needing to be thickened, such as grape juice, coconut juice and yellow peach juice, so that an excellent thickening effect can be realized, and the bean dreg cellulose nanofiber has the characteristics of environment friendliness, sustainability, safety, sanitation, simplicity in operation and good stability.

Description

Technical Field

[0001] The present invention relates to the field of extraction of cellulose nanofibers, and particularly to the application of cellulose nanofibers extracted from soybean dregs as a thickening agent, especially as a thickening agent in the food field. Background Art

[0002] A large amount of soybean dregs is generated during the production of soy products such as soy milk and tofu. Due to the rough taste, short shelf life and troublesome processing of soybean dregs, soybean dregs are often used as feed or directly discarded, resulting in waste of resources and environmental pollution.

[0003] In addition, traditional methods for extracting cellulose nanofibers often introduce some toxic and harmful impurities (for example: 2,2,6,6-tetramethylpiperidine oxide, which is a piperidine-based nitroxide radical), making the prepared cellulose unable to meet the food safety requirements, and the possibility of application of cellulose nanofibers in the food field is limited.

[0004] Therefore, improving the high-value application of cellulose nanofibers from soybean dregs is still the direction for scientific and technological workers to continue to strive. Summary of the Invention

[0005] An object of the present application is to strip cellulose nanofibers from soybean dregs by a simple, safe and efficient method for stripping cellulose nanofibers, and then use the cellulose nanofibers from soybean dregs as a thickening agent.

[0006] Another object of the present invention is to apply cellulose nanofibers from soybean dregs that meet food safety requirements in fields such as liquid thickening, especially to provide a safe liquid thickening agent in the food field.

[0007] For this reason, the present invention provides the following technical solutions.

[0008] <1>. An application of cellulose nanofibers from soybean dregs as a liquid thickening agent, wherein the cellulose nanofibers from soybean dregs are obtained from soybean dregs by an extraction method including the following steps:

[0009] A) Adding soybean dregs to a solution obtained by mixing food-grade hydrogen peroxide and food-grade acetic acid solution in a mass ratio of 1:1 to 2:1, reacting and treating at a temperature of 60-65°C for 24-48 h, washing and filtering to obtain soybean dregs with soybean protein removed;

[0010] B) Mechanically crushing the deproteinized soybean dregs obtained in step A) to obtain micron-sized soybean dreg cellulose;

[0011] C) Mechanically stripping the micron-sized soybean dreg cellulose obtained in step B) for 1-3 h to obtain cellulose nanofibers from soybean dregs.

[0012] <2>, According to the application described above, the application is in the food field.

[0013] <3>, According to the application described above, wherein the application comprises the following steps:

[0014] Add the soybean residue nanocellulose to the liquid system to be thickened and mix, wherein the mass fraction of the soybean residue cellulose nanofibers in the mixed solution is 1.0 - 3.0%.

[0015] <4>, According to the application described in claim 3, wherein the liquid system is at least one of grape juice, coconut juice and yellow peach juice.

[0016] <5>, According to the application described in claim 1, the soybean residue cellulose nanofibers have at least one of the following properties i) and those selected from ii) - v):

[0017] i). The diameter of the soybean residue cellulose nanofibers is 10 - 70 nm;

[0018] ii). The aspect ratio of the soybean residue cellulose nanofibers is 10 - 200;

[0019] iii). The crystallinity of the soybean residue cellulose nanofibers is 80 - 90%;

[0020] iv). The surface charge of the soybean residue cellulose nanofibers is -50 - -10 mV;

[0021] <6>, In the application according to claim 1, wherein in step A), the mass concentration of the hydrogen peroxide is 7% - 30%, the mass concentration of the acetic acid is 30% - 80%, and the mass ratio of the soybean residue raw material to the reaction solution is 1:2 - 1:3.

[0022] <7>, In the application according to claim 1, wherein in step A), the hydrogen peroxide treatment temperature is 60 - 65 °C.

[0023] <8>, According to the application described in claim 1, wherein the thickening effect obtained by the application includes at least one of the following:

[0024] i) When the soybean residue cellulose nanofibers are added as a thickener to the liquid system to be thickened, and the shear rate of the thickened liquid is 0.01 - 0.04 s -1 the viscosity of the system is measured to be 856 - 25 Pa s;

[0025] ii) When the soybean residue cellulose nanofibers are added as a thickener to the liquid system to be thickened, the thickened liquid remains stable within 7 - 10 days;

[0026] iii) Add the said okara cellulose nanofibers as a thickening agent to the liquid system to be thickened, and the thickened liquid remains stable at 5 - 60 °C. Description of the Drawings

[0027] Figure 1 This is a digital photo of the untreated okara of the present invention.

[0028] Figure 2 Digital photos showing different stages are presented, namely: the okara after oxidation and the okara cellulose nanofibers. As the peeling process progresses, the okara cellulose gradually becomes smaller, and finally nano-scale cellulose is obtained.

[0029] Figure 3 Digital photos showing the thickening effect when okara cellulose nanofibers are added to coconut juice as an example of a beverage are presented.

[0030] Figure 4 Scanning electron microscope photos comparing different peeling stages of okara are presented, showing the changes in the structure and components of okara during the peeling process.

[0031] Figure 5 Transmission electron microscope photos of okara cellulose nanofibers are presented, indicating that the obtained cellulose is nano-scale okara cellulose.

[0032] Figure 6 X-ray diffraction curves of the obtained okara cellulose nanofibers are presented, indicating that nano-scale okara cellulose is obtained; a PANalytical X’pert PRO MRD X-ray diffractometer was used, the sample was evenly placed on a silicon wafer, and the data was obtained by putting them into the X-ray diffractometer together; through comparison, it is found that after the okara is nano-sized, the characteristic peaks of the nano-cellulose are more obvious.

[0033] Figure 7 Digital photos showing okara cellulose nanofibers, commercial sodium carboxymethylcellulose, and commercial xanthan gum added to grape juice respectively are presented, with the control being grape juice without adding any materials.

[0034] Figure 8 Digital photos showing okara cellulose nanofibers, commercial sodium carboxymethylcellulose, and commercial xanthan gum added to coconut juice respectively are presented, with the control being coconut juice without adding any materials.

[0035] Figure 9 Digital photos showing okara cellulose nanofibers, commercial sodium carboxymethylcellulose, and commercial xanthan gum added to yellow peach juice respectively are presented, with the control being yellow peach juice without adding any materials.

[0036] Figure 10Shows the rheological data curves measured when adding okara cellulose nanofibers and sodium carboxymethylcellulose to grape juice respectively; the HR20 rotational rheometer of TA Instruments Waters Company in the United States was used, and the relevant data of shear rate and viscosity were obtained through testing, and the corresponding curves were plotted.

[0037] Figure 11 Shows the rheological data curves obtained by adding okara cellulose nanofibers and sodium carboxymethylcellulose to grape juice respectively; the HR20 rotational rheometer of TA Instruments Waters Company in the United States was used, and the relevant data of rotational speed and storage modulus / loss modulus were obtained through testing, and the corresponding curves were plotted.

[0038] Figure 12 Shows the rheological data curves measured when adding okara cellulose nanofibers and xanthan gum to grape juice respectively; the HR20 rotational rheometer of TA Instruments Waters Company in the United States was used, and the relevant data of shear rate and viscosity were obtained through testing, and the corresponding curves were plotted.

[0039] Figure 13 Shows the rheological data curves obtained by adding okara cellulose nanofibers and xanthan gum to grape juice respectively; the HR20 rotational rheometer of TA Instruments Waters Company in the United States was used, and the relevant data of rotational speed and storage modulus / loss modulus were obtained through testing, and the corresponding curves were plotted.

[0040] Figure 14 Shows the rheological data curves measured when adding okara cellulose nanofibers and sodium carboxymethylcellulose to coconut juice respectively; the HR20 rotational rheometer of TA Instruments Waters Company in the United States was used, and the relevant data of shear rate and viscosity were obtained through testing, and the corresponding curves were plotted.

[0041] Figure 15 Shows the rheological data curves obtained by adding okara cellulose nanofibers and sodium carboxymethylcellulose to coconut juice respectively; the HR20 rotational rheometer of TA Instruments Waters Company in the United States was used, and the relevant data of rotational speed and storage modulus / loss modulus were obtained through testing, and the corresponding curves were plotted.

[0042] Figure 16 Shows the rheological data curves measured when adding okara cellulose nanofibers and xanthan gum to coconut juice respectively; the HR20 rotational rheometer of TA Instruments Waters Company in the United States was used, and the relevant data of shear rate and viscosity were obtained through testing, and the corresponding curves were plotted.

[0043] Figure 17Shows the rheological data curves obtained by adding okara cellulose nanofibers and xanthan gum to coconut juice respectively; The HR20 rotational rheometer of TA Instruments Waters Company in the United States was used. Through testing, the relevant data of rotational speed and storage modulus / loss modulus were obtained, and the corresponding curves were plotted.

[0044] Figure 18 Shows the rheological data curves obtained by adding okara cellulose nanofibers and sodium carboxymethylcellulose to yellow peach juice respectively; The HR20 rotational rheometer of TA Instruments Waters Company in the United States was used. Through testing, the relevant data of shear rate and viscosity were obtained, and the corresponding curves were plotted.

[0045] Figure 19 Shows the rheological data curves obtained by adding okara cellulose nanofibers and sodium carboxymethylcellulose to yellow peach juice respectively; The HR20 rotational rheometer of TA Instruments Waters Company in the United States was used. Through testing, the relevant data of rotational speed and storage modulus / loss modulus were obtained, and the corresponding curves were plotted.

[0046] Figure 20 Shows the rheological data curves obtained by adding okara cellulose nanofibers and xanthan gum to yellow peach juice respectively; The HR20 rotational rheometer of TA Instruments Waters Company in the United States was used. Through testing, the relevant data of shear rate and viscosity were obtained, and the corresponding curves were plotted.

[0047] Figure 21 Shows the rheological data curves obtained by adding okara cellulose nanofibers and xanthan gum to yellow peach juice respectively; The HR20 rotational rheometer of TA Instruments Waters Company in the United States was used. Through testing, the relevant data of rotational speed and storage modulus / loss modulus were obtained, and the corresponding curves were plotted. Detailed implementation mode

[0048] To further understand the present invention, the preferred implementation schemes of the present invention are described below in combination with embodiments. However, these descriptions are only to further illustrate the specific implementation process and features of the present invention, rather than a limitation on the scope of the claims.

[0049] 1) Preparation of okara nanocellulose

[0050] A large amount of okara is generated during the production of soy products such as soy milk and tofu. Due to the rough taste, short shelf life and troublesome processing of okara, okara is often used as feed or directly discarded, resulting in waste of resources and environmental pollution.

[0051] In addition, traditional methods for extracting cellulose nanofibers often introduce some toxic and harmful impurities, making the prepared cellulose unable to meet the requirements of food safety. This application provides a method for exfoliating edible cellulose nanofibers from soybean dregs.

[0052] In the present invention, the term "soybean dregs" refers to the by-product in the process of producing soy products such as soy milk or tofu, mainly derived from the residue after steps such as soaking, grinding, boiling, and separating with soybeans as the main raw material.

[0053] In the present invention, the term "cellulose nanofibers" means that the material scale is in the nanometer scale range. Preferably, the obtained cellulose nanofibers have a diameter distribution range of 10 - 70 nm, and more preferably, they also satisfy at least one of the following: the aspect ratio distribution range is 10 - 200, the crystallinity distribution range is 80 - 90%, and the surface charge distribution range is -50 - -10 mV. Without being bound by any theory, the applicant believes that soybean dreg cellulose nanofibers with a high aspect ratio exhibit significant advantages in thickening performance. This structural characteristic enables them to form a dense network structure in liquids that require thickening, thereby effectively increasing the viscosity of the liquid; soybean dreg cellulose nanofibers with high crystallinity exhibit better water retention performance and can effectively retain moisture; while the negative charges on the surface of soybean dreg cellulose nanofibers enhance the repulsive force between the soybean dreg cellulose nanofibers, forming a more stable network structure, which helps to obtain a more stable thickening effect and enables the thickened liquid to maintain good stability.

[0054] In the present invention, the term "edible exfoliation method" refers to an exfoliation method of edible cellulose nanofibers obtained from soybean dregs through oxidative treatment with food-grade hydrogen peroxide in an acidic environment provided by food-grade acetic acid and subsequent mechanical treatment.

[0055] The extraction methods applicable to extracting food-safe cellulose nanofibers from soybean dregs include the following steps:

[0056] A) Add soybean dregs to a solution in which food-grade hydrogen peroxide and food-grade acetic acid solution are mixed at a mass ratio of 1:1 - 2:1, and react at a temperature of 60 - 65 °C for 24 - 48 h. After the reaction is completed, wash and filter to obtain soybean dregs with soybean protein removed;

[0057] B) Mechanically crush the deproteinized soybean dregs obtained in step A) to obtain micron-sized (diameter 10 - 100 μm) soybean dreg cellulose;

[0058] C) Mechanically exfoliate the micron-sized soybean dreg cellulose obtained in step B) for 1 - 3 h to obtain a cellulose nanofiber dispersion with a mass fraction of 1 - 2 wt% for preservation.

[0059] Preferably, before step A), it may further include: washing the wet soybean dregs with deionized water multiple times to remove residual other impurities.

[0060] In step A) of the invention, preferably, the mass concentration of the hydrogen peroxide is 7% - 30%, preferably 7.5% - 10%; the mass concentration of the acetic acid is 30% - 80%, preferably 70% - 80%, the treatment time of the hydrogen peroxide is 24 - 48 h for reaction treatment, and the preferred time is 30 - 40 h. The mass ratio of the soybean dregs raw material to the reaction solution is 1:2 - 1:3, and the treatment temperature of the hydrogen peroxide is 60 - 65 °C.

[0061] In step B) of the invention, preferably, the mechanical crushing means includes any one of a beater, a grinder, and a pulverizer.

[0062] In step C) of the invention, preferably, the mechanical peeling of the micron - level soybean dregs cellulose includes any one or a combination of any of a cell ultrasonic crusher, a ball mill, and a high - pressure homogenizer. The mechanical peeling time is 2 - 3 h, and the mass fraction of the obtained cellulose nanofibers is 1 - 2 wt%.

[0063] The above aims to make the extracted soybean dregs cellulose nanofibers have a high aspect ratio and excellent thermodynamic stability, and have an excellent thickening effect. Especially when this cellulose raw material is applied in the field of food thickening, it provides a liquid thickening raw material for the food thickening field.

[0064] In the present invention, the nano - level soybean dregs cellulose obtained by the food - grade peeling method has at least property i) and at least one of the following properties ii) - iv), preferably at least 2 items, more preferably at least 3 items, and even more preferably at least 4 items:

[0065] i). The diameter of the soybean dregs cellulose nanofibers is 10 - 70 nm (for example: it can be 10 nm, 15 nm, 20 nm, 25 nm, 35 nm, 50 nm, 60 nm, etc., and can also be within the range formed by these values, such as 10 - 15 nm, 25 - 50 nm, etc.). The diameter is preferably 10 - 50 nm, and more preferably 35 - 40 nm;

[0066] ii). The aspect ratio of the soybean dregs cellulose nanofibers is 10 - 200 (for example: it can be 20, 50, 80, 100, 125, 170, 200, etc., and can also be within the range formed by these values, such as 80 - 100, 100 - 200, etc.). The aspect ratio is preferably 100 - 200, and more preferably 120 - 170;

[0067] iii). The crystallinity of the soybean dreg cellulose nanofibers is 80-90% (for example, it can be 85%, 88%, 90%, etc., or it can be within the range formed by these values, such as 85%-88%, etc.). The crystallinity is preferably 85-90%, and more preferably 88-90%.

[0068] iv). The surface charge of the soybean dreg cellulose nanofibers is -50 to -10 mV (for example, it can be -50, -40, -30, -20, -10, etc., or it can be within the range formed by these values, such as -50 to -40, etc.). It is preferably -40 to -20 mV, and more preferably -35 to -25 mV.

[0069] In addition, it is worth pointing out that in the process of extracting nanoscale cellulose from soybean dregs used in the present disclosure, no toxic and harmful reagents are added, the environmental pollution is small, the energy consumption is low, the peeling method is simple and efficient, and the obtained soybean dreg cellulose nanofibers have characteristics such as food safety and high aspect ratio.

[0070] 2) The soybean dreg cellulose nanofibers are used in the field of food thickening

[0071] The purpose of this application is to provide an application of the obtained food-safe soybean dreg cellulose nanofibers in liquid thickening. Specifically, the obtained food-safe soybean dreg cellulose nanofibers with a certain concentration are added to the liquid system, and the liquid system is preferably a beverage, more preferably a fruit juice beverage, and most preferably at least one of grape juice, coconut juice and / or yellow peach juice.

[0072] The food field refers to various substances that can be eaten by people, including fields such as animal and plant foods, food processing, and various flavorings.

[0073] The term "thickening" refers to the operation of separating solid particles suspended in a liquid into a thick slurry and separating them from the liquid, also known as precipitation concentration or sedimentation concentration, which is a process. Specifically, in the present invention, it refers to adding the obtained soybean dreg cellulose nanofibers to the liquid in a certain proportion to increase the viscosity and stability of the liquid and change the rheological properties of the liquid.

[0074] In the present disclosure, the application of thickening includes the following steps:

[0075] a) Heat the above-mentioned soybean dreg cellulose nanofibers in a water bath for concentration to prepare a cellulose nanofiber dispersion with a mass concentration of 1-3 wt%, preferably 1-2 wt%, and more preferably 1-1.5 wt%

[0076] b) Add the okara cellulose nanofiber suspension obtained in step a) to the system to be thickened (for example, grape juice, coconut juice, yellow peach juice, etc.). The okara cellulose and the thickening liquid are mixed at a mass ratio of 1:20 to 1:1000, preferably 1:100 to 1:500, more preferably 1:200 to 1:400. Then, disperse them evenly by mechanical treatment and let them stand in the freezer for 15 - 30 min;

[0077] c) Take out the uniformly dispersed mixed solution obtained in step b) and place it in a 10 mL beaker. Refer to the test method mentioned in this literature (Cho H M, Yoo B. Rheological characteristics of cold thickened beverages containing xanthan gum–based food thickeners used for dysphagia diets[J]. Journal of the Academy of Nutrition and Dietetics, 2015, 115(1):106 - 111.) to conduct rheological tests.

[0078] d) According to the characteristics of the test mixed solution, select the viscosity measurement method: Measure with a rheometer, rheometer model: HR20 of TA Instruments Waters Corporation, USA. Select a parallel plate with a diameter of 60 mm and measure the change in the solution viscosity at a shear rate from 0.01 - 100 s -1 under the condition of 8℃, as well as the change in the storage modulus and loss modulus of the solution at a rotational speed of 1 - 100 rad s -1 under the condition of 8℃.

[0079] In the present invention, the mechanical treatment in step b) is carried out using a magnetic stirrer, a constant - speed mechanical stirrer, a high - speed shearer, a cell disruptor, etc. Preferably, it is a magnetic stirrer and a cell disruptor, and more preferably a cell disruptor; the rate range of the mechanical stirring is 300 - 1000 r / min for 15 - 30 min, preferably 500 - 800 r / min for 15 - 30 min, and more preferably 500 r / min for 30 min; the standing time in the refrigerator is preferably 15 - 20 min, and more preferably 15 - 17 min.

[0080] In the present invention, adding okara cellulose nanofibers to the thickened liquid system forms good stability between the okara cellulose nanofibers and the thickening system, and has a good thickening effect; enabling the thickening system to have at least 1 of the following properties, preferably at least 2, more preferably at least 3, and most preferably having all of the following properties simultaneously:

[0081] i) Add the soybean residue cellulose nanofibers as a thickening agent to the liquid system to be thickened. When the shear rate of the thickened liquid is 0.01 - 0.04 s -1 , the viscosity of the system is measured to be 856 - 25 Pa s;

[0082] ii) Add the soybean residue cellulose nanofibers as a thickening agent to the liquid system to be thickened, and the thickened liquid remains stable within 7 - 10 days;

[0083] iii) Add the soybean residue cellulose nanofibers as a thickening agent to the liquid system to be thickened, and the thickened liquid remains stable at 5 - 60 °C.

[0084] To further understand the present invention, the following further elaborates on the application of soybean residue cellulose nanofibers in the field of food thickening and its corresponding thickening effect in combination with examples. The protection scope of the present invention is not limited by the following examples.

[0085] Raw material preparation example 1

[0086] A) Wash 2000 g of soybean residue with deionized water repeatedly to remove excess impurities;

[0087] B) Add the washed soybean residue to a pre-prepared hydrogen peroxide and acetic acid solution. The mass concentration of the hydrogen peroxide solution is 10%, the mass concentration of the acetic acid solution is 75%, and the mixing mass ratio of the two is 1:1. The reaction temperature is 60 °C, and the reaction time is 40 h;

[0088] C) Shear and crush the reacted soybean residue cellulose in a pulper at a rotation speed of 30,000 revolutions per minute for 2 h to obtain micron-sized soybean residue cellulose with a diameter between 10 - 100 μm.

[0089] D) Subject the micron-sized soybean residue cellulose obtained in step C) to peeling treatment at a pressure of 100 - 1200 bar for 1 h through a high-pressure homogenizer to obtain soybean residue cellulose nanofibers.

[0090] The obtained soybean residue cellulose nanofibers have a diameter of 30 - 70 nm, a length-to-diameter ratio of 20 - 100, and a crystallinity of 90%.

[0091] Raw material preparation example 2

[0092] A) Wash 2000 g of soybean residue with deionized water repeatedly to remove excess impurities;

[0093] B) Add the cleaned okara to the pre-prepared hydrogen peroxide and acetic acid solutions. The mass concentration of the hydrogen peroxide solution is 7.5%, the mass concentration of the acetic acid solution is 80%, the mixing mass ratio of the two is 1:1, the reaction temperature is 65 °C, and the reaction time is 24 h;

[0094] C) Pulverize the okara cellulose after the reaction in a beater at a speed of 43,000 revolutions per minute for 1 h to obtain micro-scale okara cellulose with a diameter between 10 - 100 μm.

[0095] D) Subject the micro-scale okara cellulose obtained in step C) to a peeling treatment at a pressure of 100 - 1200 bar for 1 h through a high-pressure homogenizer to obtain okara cellulose nanofibers.

[0096] The obtained okara cellulose nanofibers have a diameter of 20 - 50 nm, an aspect ratio of 10 - 100, and a crystallinity of 85%.

[0097] Example 1

[0098] a) Heat the above-mentioned okara cellulose nanofibers in a water bath for concentration to prepare a cellulose nanofiber dispersion with a mass concentration of 1 wt%.

[0099] b) Mix the okara cellulose nanofiber suspension obtained in step a) and grape juice at a mass ratio of 1:200, and let it stand in a freezer for 20 min to obtain a uniformly mixed grape juice;

[0100] c) Take out the uniformly dispersed grape juice obtained in step b) and place it in a 10 mL beaker, and conduct a rheological test with reference to the test method mentioned in this literature (Cho H M, Yoo B. Rheological characteristics of cold thickened beverages containing xanthan gum–based food thickeners used for dysphagia diets[J]. Journal of the Academy of Nutrition and Dietetics, 2015, 115(1):106 - 111.).

[0101] d) According to the characteristics of the tested grape juice, select a viscosity measurement method: measure with a rheometer, rheometer model: HR20 of TA Instruments Waters Corporation, USA. Select a parallel plate with a diameter of 60 mm, and measure the change in the solution viscosity at a shear rate from 0.01 - 100 s -1 under the condition of 8 °C, as well as the change in the storage modulus and loss modulus of the solution at a rotation speed of 1 - 100 rad s -1 under the condition of 8 °C.

[0102] When the okara cellulose nanofibers are added to grape juice, they exhibit excellent stability and thickening effect. From the curves of shear rate and viscosity, it can be seen that compared with commercial xanthan gum and commercial sodium carboxymethyl cellulose, the okara cellulose nanofibers of this application exhibit higher viscosity. The viscosity at a shear rate of 0.1 s -1 is 5481.34 Pa s, far greater than that of xanthan gum and sodium carboxymethyl cellulose, and has a better thickening effect. From the curves of rotational speed and storage modulus / loss modulus, it can be seen that compared with commercial gelatin and commercial sodium carboxymethyl cellulose, the storage modulus of the okara cellulose nanofibers is much greater than the loss modulus, and the difference is about 6.6 MPa. At this time, the solid characteristics of the grape juice are more obvious, and the thickening effect of the okara cellulose nanofibers is more obvious.

[0103] Example 2

[0104] a) The above-mentioned okara cellulose nanofibers are heated and concentrated in a water bath to prepare a cellulose nanofiber dispersion with a mass concentration of 1 wt%.

[0105] b) The okara cellulose nanofiber suspension obtained in step a) and coconut milk are mixed at a mass ratio of 1:200 and left to stand in a freezer for 20 min to obtain uniformly mixed coconut milk;

[0106] c) The uniformly dispersed coconut milk obtained in step b) is taken out and placed in a 10 mL beaker, and rheological tests are carried out with reference to the test method mentioned in this literature (Cho H M, Yoo B. Rheological characteristics of cold thickened beverages containing xanthan gum–based food thickeners used for dysphagia diets[J]. Journal of the Academy of Nutrition and Dietetics, 2015, 115(1): 106-111.).

[0107] d) According to the characteristics of the tested grape juice, a viscosity measurement method is selected: measured with a rheometer, rheometer model: HR20 of TA Instruments Waters Corporation, USA. A parallel plate with a diameter of 60 mm is selected, and the change in the solution viscosity at a shear rate from 0.01 - 100 s -1 is measured at 8 °C, as well as the change in the storage modulus and loss modulus of the solution at a rotational speed of 1 - 100 rad s -1

[0108] ​Adding the cellulose nanofibers from soybean dregs into coconut milk shows excellent stability and thickening effect. From the curves of shear rate and viscosity, it can be seen that compared with commercial xanthan gum and commercial sodium carboxymethylcellulose, the cellulose nanofibers from soybean dregs in this application show higher viscosity. The viscosity at a shear rate of 0.1 s -1 is 856.331 Pa s, far greater than that of xanthan gum and sodium carboxymethylcellulose, and has a better thickening effect. From the curves of rotational speed and storage modulus / loss modulus, it can be seen that compared with commercial gelatin and commercial sodium carboxymethylcellulose, the storage modulus of the cellulose nanofibers from soybean dregs is much greater than the loss modulus, and the difference is about 15 MPa. At this time, the solid characteristics of coconut milk are more obvious, and the thickening effect of the cellulose nanofibers from soybean dregs is more obvious.

[0109] Example 3

[0110] a) Heat-concentrate the above-mentioned cellulose nanofibers from soybean dregs in a water bath to prepare a cellulose nanofiber dispersion with a mass concentration of 1 wt%.

[0111] b) Mix the suspension of cellulose nanofibers from soybean dregs obtained in step a) and yellow peach juice at a mass ratio of 1:200, and let it stand in a freezer for 20 min to obtain uniformly mixed coconut milk;

[0112] c) Take out the uniformly dispersed yellow peach juice obtained in step b) and place it in a 10 mL beaker, and refer to the testing method mentioned in this literature (Cho H M, Yoo B. Rheological characteristics of cold thickened beverages containing xanthan gum–based food thickeners used for dysphagia diets[J]. Journal of the Academy of Nutrition and Dietetics, 2015, 115(1):106-111.) for rheological testing.

[0113] d) According to the characteristics of the tested grape juice, select the viscosity measurement method: measure with a rheometer, rheometer model: HR20 of TA Instruments Waters Corporation, USA. Select parallel plates with a diameter of 60 mm, and measure the change in the solution viscosity at a shear rate from 0.01 - 100 s -1 under the condition of 8℃, and the change in the storage modulus and loss modulus of the solution at a rotational speed of 1 - 100 rad s -1 under the condition of 8℃.

[0114] Adding the okara cellulose nanofibers to the yellow peach juice shows excellent stability and thickening effect. From the curves of shear rate and viscosity, it can be seen that compared with commercial xanthan gum and commercial sodium carboxymethyl cellulose, the okara cellulose nanofibers of this application show higher viscosity. The viscosity at a shear rate of 0.1 s -1 is 2719.57 Pa s, far greater than that of xanthan gum and sodium carboxymethyl cellulose, and has a better thickening effect. From the curves of rotational speed and storage modulus / loss modulus, it can be seen that compared with commercial gelatin and commercial sodium carboxymethyl cellulose, the storage modulus of the okara cellulose nanofibers is much greater than the loss modulus, and the difference is about 28 MPa. At this time, the solid characteristics of the yellow peach juice are more obvious, and the thickening effect of the okara cellulose nanofibers is more obvious.

[0115] Comparative Example 1

[0116] This comparative example is the same as Example 1, except that commercial sodium carboxymethyl cellulose is added to the grape juice, and its thickening effect is difficult to meet the actual application requirements.

[0117] Figure 7 、 Figure 10 and Figure 11 are the digital photos and rheological data obtained by using different thickening materials in Example 1 and Comparative Example 1.

[0118] Comparative Example 2

[0119] This comparative example is the same as Example 1, except that commercial xanthan gum is added to the grape juice, and its thickening effect is difficult to meet the actual application requirements.

[0120] Figure 7 、 Figure 12 and Figure 13 are the digital photos and rheological data obtained by using different thickening materials in Example 1 and Comparative Example 2.

[0121] Comparative Example 3

[0122] This comparative example is the same as Example 2, except that commercial sodium carboxymethyl cellulose is added to the coconut juice, and its thickening effect is difficult to meet the actual application requirements.

[0123] Figure 8 、 Figure 14 and Figure 15 are the digital photos and rheological data obtained by using different thickening materials in Example 2 and Comparative Example 3.

[0124] Comparative Example 4

[0125] This comparative example is the same as Example 2, except that commercial xanthan gum is added to the coconut juice, and its thickening effect is difficult to meet the actual application requirements.

[0126] Figure 8 , Figure 16 and Figure 17 are the digital photos and rheological data obtained by using different thickening materials in Example 2 and Comparative Example 4.

[0127] Comparative Example 5

[0128] This comparative example is the same as Example 3, except that commercially available sodium carboxymethyl cellulose is added to the yellow peach juice, and its thickening effect is difficult to meet the actual application requirements.

[0129] Figure 9 , Figure 18 and Figure 19 are the digital photos and rheological data obtained by using different thickening materials in Example 3 and Comparative Example 5.

[0130] Comparative Example 6

[0131] This comparative example is the same as Example 3, except that commercially available xanthan gum is added to the yellow peach juice, and its thickening effect is difficult to meet the actual application requirements.

[0132] Figure 9 , Figure 20 and Figure 21 are the digital photos and rheological data obtained by using different thickening materials in Example 3 and Comparative Example 6.

[0133] Industrial Applicability

[0134] The okara cellulose nanofibers obtained in the present disclosure are added to liquids such as grape juice, coconut juice and yellow peach juice, verifying that the material has good dispersibility and thickening stability, and thus will have broad application prospects in related fields such as food thickening.

[0135] The above descriptions of the specific embodiments and examples are only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle and spirit of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. Use of defatted soybean residue cellulose nanofibers extracted from defatted soybean residue as a liquid thickener, wherein the defatted soybean residue cellulose nanofibers are obtained from defatted soybean residue by an extraction method comprising the following steps: A) Adding defatted soybean residue to a solution in which food-grade hydrogen peroxide and food-grade acetic acid solution are mixed at a mass ratio of 1:1 to 2:1, reacting and treating at a temperature of 60-65 °C for 24-48 h, washing and filtering to obtain defatted soybean residue with soybean protein removed; B) Mechanically crushing the defatted soybean residue obtained in step A) to obtain micron-sized defatted soybean residue cellulose; C) Mechanically peeling the micron-sized defatted soybean residue cellulose obtained in step B) for 1-3 h to obtain defatted soybean residue cellulose nanofibers.

2. The use according to claim 1, wherein the use is in the food field.

3. The use according to claim 1, wherein the use comprises the following steps: Adding defatted soybean residue cellulose nanofibers to the liquid system to be thickened and mixing, wherein the mass fraction of the defatted soybean residue cellulose nanofibers in the mixed solution is 1.0-3.0%.

4. The application according to claim 3, wherein, The liquid system is at least one of grape juice, coconut juice and yellow peach juice.

5. The use according to claim 1, wherein the defatted soybean residue cellulose nanofibers have at least one of the following properties i) and those selected from ii)-v): i). The diameter of the defatted soybean residue cellulose nanofibers is 10-70 nm; ii). The aspect ratio of the defatted soybean residue cellulose nanofibers is 10-200; iii). The crystallinity of the defatted soybean residue cellulose nanofibers is 80-90%; iv). The surface charge of the defatted soybean residue cellulose nanofibers is -50 to -10 mV.

6. In the use according to claim 1, wherein in step A), the mass concentration of the hydrogen peroxide is 7%-30%, the mass concentration of the acetic acid is 30%-80%, and the mass ratio of the defatted soybean residue to the reaction solution is 1:2 to 1:

3.

7. In the use according to claim 1, wherein in step A), the hydrogen peroxide treatment temperature is 60-65 °C.

8. The use according to claim 1, wherein the thickening effect obtained by the use comprises at least one of the following: i) Add the soybean residue cellulose nanofibers as a thickening agent to the liquid system to be thickened. When the shear rate of the thickened liquid is 0.01 - 0.04 s -1 , the viscosity of the system is measured to be 856 - 25 Pa s; ii) Adding the defatted soybean residue cellulose nanofibers as a thickener to the liquid system to be thickened, and the thickened liquid remains stable for 7-10 days; iii) Adding the defatted soybean residue cellulose nanofibers as a thickener to the liquid system to be thickened, and the thickened liquid remains stable at 5-60 °C.

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