CN121312800A - Application of a soluble nanocellulose in food thickeners - Google Patents

Abstract

The invention belongs to the technical field of food thickeners, and discloses application of dissolved nanocellulose in a food thickener. The invention uses the dissolved nano cellulose as the food thickener. The dissolved nano cellulose is prepared by 1) dissolving cellulose by adopting a solvent to obtain a cellulose solution, 2) mixing the cellulose solution with an antisolvent, performing nanoscale dispersion to obtain a nano cellulose dispersion, and 3) washing and concentrating the nano cellulose dispersion. The dissolved nano cellulose of the invention constructs a network structure through physical entanglement among nano fibers, thereby realizing high-efficiency and stable rheological control performance. When the nano-cellulose thickener is used in food, the thickening viscosity of the dissolved nano-cellulose exceeds that of commercial food thickeners, and the dissolved nano-cellulose thickener has excellent viscosity retention capacity under different pH values and salt ion environments.

Description

Application of dissolved nanocellulose in food thickener

Technical Field

The invention belongs to the technical field of food processing and additives, and particularly relates to an application of green, efficient and stable dissolved nanocellulose in a food thickener.

Background

At present, thickening agents widely used in the food industry, such as pectin, gelatin, hydroxypropyl methylcellulose and the like, play an important role in regulating the viscosity and mouthfeel of foods. However, these conventional thickeners have problems in that (1) they are limited in source and have large price fluctuations, (2) they are sensitive to pH and salt ions and are prone to gel failure or delamination, and (3) they are partially derived from animal tissues (e.g., gelatin) and are difficult to meet the needs of specific consumer groups.

Nanocellulose has been recently considered as a new generation of food thickener because of its wide source, reproducibility, and good biocompatibility. The nanocellulose prepared by the mechanical method has the defects of short fiber, poor dispersibility, weak capability of forming a network structure, and limited thickening performance in food. Commercial TEMPO oxidized nanocellulose (ToCNF) contains carboxylic acid groups and oxidized residues despite its high viscosity, presents food safety concerns, and negatively charged fibers are susceptible to flocculation precipitation under salt-containing or extreme pH conditions, severely affecting thickening effect and product stability.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention aims to provide the application of the dissolved nanocellulose in food thickening, which is used as a food thickener. The invention uses the dissolved nano cellulose as a thickening agent for food, and the thickening system almost completely depends on the physical entanglement effect between the nano cellulose to realize the thickening effect without chemical modification or charge group introduction, so that stable rheological property can be maintained under the extreme food processing conditions of acidity, alkalinity, high salt ion and the like.

The aim of the invention is achieved by the following technical scheme:

use of dissolved nanocellulose as a food thickener.

The dissolved nanocellulose is prepared by the following method:

1) Dissolving cellulose by using a solvent to obtain a cellulose solution, wherein the cellulose raw material accounts for 1-10wt% of the mass of the ionic liquid;

2) Mixing a cellulose solution with an antisolvent, and then performing nanoscale dispersion to obtain a nano cellulose dispersion, wherein the antisolvent comprises more than one of water and ethanol, the nanoscale dispersion mode is one or more of high-speed shearing and homogenization, and the mass ratio of the cellulose solution to the antisolvent is 1 (1-10);

3) Washing and concentrating the nano cellulose dispersoid to obtain a dissolved nano cellulose water dispersoid or dissolved nano cellulose, wherein the washing refers to washing by water.

The cellulose raw materials comprise cotton, kapok and cotton linters.

The solvent is more than one of 1, 5-diazabicyclo [4.3.0] -5-nonene-alkane chloride (C ₅～C₁₀) and 1, 8-diazabicyclo undec-7-ene-alkane chloride (C ₅～C₁₀).

The 1, 5-diazabicyclo [4.3.0] -5-nonene-alkane chloride is obtained by reacting 1, 5-diazabicyclo [4.3.0] -5-nonene with C ₅～C₁₀ alkane chloride, wherein the C ₅～C₁₀ alkane chloride is 1-chloropentane, 1-chlorohexane, 1-chloro-heptane, 1-chlorooctane, 1-chlorononane and 1-chlorodecane, and the mol ratio of the 1, 5-diazabicyclo [4.3.0] -5-nonene to the C ₅～C₁₀ alkane chloride is 1:1;

The 1, 8-diazabicyclo undec-7-ene-alkane chloride is prepared by reacting 1, 8-diazabicyclo undec-7-ene with C ₅～C₁₀ alkane chloride, wherein the C ₅～C₁₀ alkane chloride is 1-chloropentane, 1-chlorohexane, 1-chloro-heptane, 1-chlorooctane, 1-chlorononane and 1-chlorodecane, and the molar ratio of the 1, 8-diazabicyclo undec-7-ene to the C ₅～C₁₀ alkane chloride is 1:1.

The high-speed shearing condition is that the shearing rate is more than or equal to 10000rpm, the shearing time is 5-20min, the homogenizing condition is that the rotating speed is more than or equal to 5000rpm, and the homogenizing time is 10-25min.

The antisolvent is water, ethanol or a mixed solution of water and ethanol, wherein the mass ratio of water to ethanol is (0-100) (100-0), the total amount of water and ethanol is 100, the dosage of water is not 0 when the mixed solution is mixed, and the dosage of ethanol is not 0.

The application comprises the following steps:

The dissolved nano cellulose is dispersed by water to obtain thickener dispersion liquid, wherein the mass concentration of the dispersion liquid is 0.1% -2% (preferably 0.5% -2.5%, more preferably 0.8% -2%);

the thickener dispersion is mixed with the liquid food to achieve the thickening effect of the thickener.

The mass ratio of the thickener to the liquid food is 1:50-1:1000, preferably 1:100-1:1000.

The mixing treatment comprises, but is not limited to, magnetic stirring (100-800 r/min,2-20 min), homogenizing (3000-8000 rpm,5-25 min), ultrasonic treatment (more than or equal to 400W,5-30 min), and the like.

Such liquid foods include, but are not limited to, milk, juice, soda, rice paste, vegetable protein beverages, and the like.

Compared with the existing food thickener, the invention has the following beneficial effects:

(1) The thickener has high viscosity, and can remarkably improve the viscosity of a food system under low concentration by constructing a compact three-dimensional network;

(2) The thickener has strong environmental adaptability, and the viscosity is almost unchanged at different pH values (3-10) and calcium ion concentration (0-50 mM);

(3) The safety is high, no toxic residual groups such as aldehyde groups, carboxylic acid groups and the like are contained, and the safety is high;

(4) The method is widely applicable to various foods such as dairy products, fruit juice, seasonings, protein drinks and the like;

(5) The process is simple, and the thickening process only needs conventional stirring and homogenizing dispersion and does not need to be in charge of equipment or high-energy treatment.

Drawings

FIG. 1 is a graph of milk thickening experiments for example 1 (dissolved nanocellulose milk thickening fluid: right panel) and comparative experiment 1 (non-thickener milk aqueous solution: left panel) thereof.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but embodiments of the present invention are not limited thereto.

Thickening treatment of liquid food:

The dispersion liquid of the thickening agent is added into the liquid food to be treated according to the mass ratio of 1:50-1:1000 (preferably 1:100-1:800, more preferably 1:200-1:500), and is dispersed by using a mechanical mode, wherein the mechanical mode comprises, but is not limited to, magnetic stirring (100-800 r/min,2-20 min), homogenization (3000-8000 rpm,5-25 min), ultrasonic treatment (more than or equal to 400W,5-30 min) and the like. And standing the mixed solution in a refrigerator for 10-20 min.

And (3) testing rheological property, namely taking 5-10 mL of the treated mixed solution, and testing by adopting a rheometer. The change in viscosity at a shear rate in the range of 0.01 to 100s ^-1 and the change in storage modulus (G ') and loss modulus (G') at an angular frequency of 1 to 100rad/s are measured at 25 ℃.

Thickening effect evaluation the thickening liquid system to which the dissolved nanocellulose is added exhibits an excellent physical cross-linked rheological network structure, and has at least one of the following characteristics:

a. under the condition that the shear rate is 0.05-0.15 s ^-1, the viscosity of the system reaches 200-500 Pa.s;

b. The viscosity is basically unchanged in the pH range of 3-10, and the system is stable and has no layering or precipitation;

c. the viscosity is basically unchanged in the range of 0-50mM calcium ions, and the system is stable and has no layering or precipitation.

The dissolved nanocellulose dispersion in the examples was prepared by the following method:

1) 1, 5-diazabicyclo [4.3.0] -5-nonene-alkane chloride (C8) (1, 5-diazabicyclo [4.3.0] -5-nonene and 1-chlorooctane are obtained by stirring at 300rpm for 24 hours at 60 ℃ according to a 1:1 molar ratio), heating to 90 ℃, adding kapok (mass of the kapok is 3% of that of the ionic liquid), stirring at 300rpm for 2 hours, uniformly mixing and dissolving to obtain a cellulose solution;

2) Heating water to 90 ℃ to obtain an antisolvent;

3) Slowly adding the antisolvent into the cellulose solution in a mass ratio of the cellulose solution to the antisolvent of 1:5 for homogenization (12,000 rpm,20 min);

4) Centrifugal washing with water to obtain dissolved nano cellulose dispersion liquid with concentration of 1wt%, 1.3wt% and 0.8wt% (different concentrations can be configured with water).

Example 1 thickening application of dissolved nanocellulose in milk

The dissolved nanocellulose dispersion (mass concentration 1%) was added to fresh whole milk powder at room temperature with stirring (400 rpm) at a mass ratio of dispersion to milk powder of 15:85 (w/w), magnetically stirred at 200rpm for 2h, and then left to stand in a 4 ℃ refrigerator for 15min. Through rheological test, the viscosity is 289.73 Pa.s under the shearing rate of 0.1s ^-1, the viscosity change is less than 2% after the pH is adjusted to 3 or 10, and the viscosity change rate is less than 3% under the condition of 50mM CaCl ₂, so that the system has no layering or precipitation.

The milk thickening profiles of example 1 (dissolved nanocellulose milk thickening fluid: right panel) and its comparative experiment 1 (non-thickener aqueous milk solution: left panel) are shown in fig. 1.

Comparative experiment 1 (no thickener):

example 1 under the same conditions, dissolved nanocellulose was substituted for pure water. The initial viscosity was 0.07 Pa.s.

Comparative experiment 2 (ToCNF):

Example 1 under the same conditions, the dissolved nanocellulose dispersion was replaced by a 1wt% tempo oxidized nanocellulose (ToCNF) dispersion. The initial viscosity was 185.91 Pa.s, but the viscosity was more than 400% changed at pH 9 and more than 200% (viscosity reduction) at 50mM CaCl ₂, and significant flocculation precipitation occurred.

Comparative experiment 3 (pectin):

after 1% pectin is added, the initial viscosity of the milk is about 123.86 Pa.s, layering occurs under the condition of pH 3, and the mouthfeel is obviously changed.

Example 2 thickening application of dissolved nanocellulose in orange juice

Fresh concentrated orange juice (12% of soluble solids) was taken and dissolved nanocellulose dispersion (1.3% by mass) was added with stirring (400 rpm) at room temperature, the mass ratio of dispersion to orange juice being 10:90 (w/w). Magnetic stirring was carried out at 300rpm for 1.5h, followed by resting in a 4℃refrigerator for 20min. Through rheological test, the viscosity is 356.42 Pa.s under the shearing rate of 0.1s ^-1, the viscosity change rate is lower than 1% after the pH is adjusted to 3 or 9, and the viscosity change rate is lower than 2% under the condition of 50mM CaCl ₂, so that the system has no turbidity or precipitation.

Comparative experiment 1 (no thickener):

example 2 under the same conditions, the dissolved nanocellulose was replaced with an equal amount of pure water. The initial viscosity was 0.05 Pa.s.

Comparative experiment 2 (ToCNF):

Example 2 under the same conditions, the dissolved nanocellulose dispersion was replaced with 1.3% TEMPO oxidized nanocellulose (ToCNF). The initial viscosity was 152.83 Pa.s, but the viscosity varied by more than 300% at pH 3 and by more than 180% at 50mM CaCl ₂, accompanied by significant precipitation.

Comparative experiment 3 (pectin):

Under the same conditions, the dissolved nanocellulose is replaced by 1.3% pectin solution, the initial viscosity of orange juice is 95.27 Pa.s, flocculation and delamination occur under the condition of 40mM CaCl ₂, and the taste is obviously rough.

Example 3 thickening application of dissolved nanocellulose in Ice cream mix

And (3) taking ice cream base mixed solution (containing cream, sugar, stabilizer and other base formulas), stirring and dissolving at 40 ℃, and then adding dissolved nanocellulose dispersion liquid (the mass concentration is 0.8%), wherein the mass ratio of the dispersion liquid to the ice cream base mixed solution is 12:88 (w/w). Treatment with homogenizer (5000 rpm,15 min) followed by 15min of rest at 4 ℃. Through rheological test, the viscosity is 412.85 Pa.s under the shearing rate of 0.1s ^-1, the viscosity change rate is lower than 2% after the pH is regulated to 4 or 9, the viscosity change rate is lower than 3% under the condition of 50mM CaCl ₂, and the ice crystal is kept uniform after 3 times of freezing and thawing, and no obvious ice crystal is separated out.

Comparative experiment 1 (no thickener):

example 3 under the same conditions, the dissolved nanocellulose was replaced with an equal amount of pure water. The initial viscosity was 0.18 Pa.s.

Comparative experiment 2 (ToCNF):

Example 3 under the same conditions, the dissolved nanocellulose was replaced with 0.8% TEMPO oxidized nanocellulose (ToCNF). The initial viscosity was 204.16 pa.s, but varied by more than 350% at pH 5 and by more than 210% (viscosity reduction) at 20mM CaCl ₂, and a slight grainy feel was observed.

Comparative experiment 3 (gelatin):

Example 3 under the same conditions, the dissolved nanocellulose was replaced with a 0.8% gelatin solution. The initial viscosity of the ice cream mixed solution is 136.59 Pa.s, the taste is roughened under the condition of pH 4, and the ice cream mixed solution is slightly layered after being left for 48 hours at low temperature.

Claims (8)

1. An application of a soluble nanocellulose as a food thickener, characterized in that: The dissolved nanocellulose was prepared by the following method: 1) The cellulose raw material is dissolved in a solvent to obtain a cellulose solution; the solvent is one or more of 1,5-diazabicyclo[4.3.0]-5-nonene-alkane chloride and 1,8-diazabicycloundec-7-ene-alkane chloride; wherein the alkane chloride in 1,5-diazabicyclo[4.3.0]-5-nonene-alkane chloride is a _C5 to _C10 alkane chloride; wherein the alkane chloride in 1,8-diazabicycloundec-7-ene-alkane chloride is a _C5 to _C10 alkane chloride; 2) The cellulose solution is mixed with an antisolvent and then dispersed at the nanoscale to obtain a nanocellulose dispersion; the antisolvent includes one or more of water and ethanol; the nanoscale dispersion method is one or more of high-speed shearing and homogenization. 3) The nanocellulose dispersion is washed and concentrated to obtain a dissolved nanocellulose aqueous dispersion or dissolved nanocellulose. 2. The application according to claim 1, characterized in that: The cellulose raw material mentioned in step 1) is 1 to 10 wt% of the solvent mass; The cellulose raw material includes one or more of cotton, kapok, and cotton linters; The 1,5-diazabicyclo[4.3.0]-5-nonene-alkane chloride is obtained by reacting 1,5-diazabicyclo[4.3.0]-5-nonene with _C5 - _C10 alkane chlorides; the _C5 - _C10 alkane chlorides are 1-chloropentane, 1-chlorohexane, 1-chloro-heptane, 1-chlorooctane, 1-chlorononane, and 1-chlorodecane; the molar ratio of 1,5-diazabicyclo[4.3.0]-5-nonene to _C5 - _C10 alkane chlorides is 1:1; 1,8-diazabicycloundec-7-ene-alkane chloride is obtained by reacting 1,8-diazabicycloundec-7-ene with _C5 - _C10 alkane chlorides; the _C5 - _C10 alkane chlorides are 1-chloropentane, 1-chlorohexane, 1-chloro-heptane, 1-chlorooctane, 1-chlorononane, and 1-chlorodecane; the molar ratio of 1,8-diazabicycloundec-7-ene to _C5 - _C10 alkane chlorides is 1:1; In step 2), the mass ratio of the cellulose solution to the antisolvent is 1:(1-10); the washing refers to washing with water. 3. The application according to claim 1, characterized in that: The conditions for high-speed shearing are: shearing rate ≥ 10000 rpm, shearing time 5-20 min; the conditions for homogenization are: rotation speed ≥ 5000 rpm, homogenization time 10-25 min. 4. The application according to claim 3, characterized in that: the conditions for high-speed shearing are: shearing rate of 10,000 to 30,000 rpm and shearing time of 5 to 20 min; the conditions for homogenization are: rotation speed of 5,000 to 20,000 rpm and homogenization time of 10 to 25 min. 5. The application according to claim 1, characterized in that: the antisolvent is water, ethanol, or a mixture of water and ethanol; when it is a mixture of water and ethanol, the mass ratio of water to ethanol is (0-100):(100-0), the total amount of water and ethanol is 100, and the amount of water used in the mixture is not 0, and the amount of ethanol used is not 0. 6. The application according to claim 1, characterized in that it includes the following steps: Dissolved nanocellulose was dispersed in water to obtain a thickener dispersion; the mass concentration of the dispersion was 0.1% to 2%. The thickener dispersion is mixed with liquid food to achieve the thickening effect of the thickener. 7. The application according to claim 6, characterized in that: the mass ratio of the thickener to the liquid food is 1:50 to 1:1000. 8. The application according to claim 6, wherein the liquid food includes milk, fruit juice, soda water, rice porridge, and plant protein beverage.