Konjac gel food, preparation method and application thereof

Abstract

The present application relates to the konjac food field, provide a kind of konjac gel food and preparation method and application, to solve the poor stability of existing konjac gel food, insufficient brittleness and poor antibacterial performance Problem.The gel food is mainly based on phosphorylated konjac glucomannan, adding chitosan / microcrystalline cellulose composite filler, carrageenan, sodium alginate, calcium salt and citrate and other auxiliary materials, by the synergistic effect of multiple components Multiple crosslinking network structure is constructed, which significantly enhances the stability and mechanical properties of gel. Temperature gradient control strategy is used in the preparation process, to realize the ordered construction and layer-by-layer solidification of gel network. The product has high gel strength, excellent brittleness, low water separation rate and excellent antibacterial performance, and can be widely used in functional foods simulating the taste of animal cartilage, with good storage stability and sensory quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of konjac food materials, in particular to a konjac gel food, a preparation method and application thereof. BACKGROUND

[0002] With the growing demand for healthy diet, functional food and plant-based alternatives, gel-based foods with unique taste and nutritional value are gradually becoming an important part of the food industry, especially in the development of functional foods that simulate the texture of animal cartilage. Konjac gel has attracted widespread attention due to its natural, low-calorie and good gel-forming properties. In such applications, gel materials not only need to have good chewiness, but also need to be close to real cartilage tissue in terms of structural strength and sensory level, so as to meet the dual needs of consumers for texture simulation and eating experience. Specifically, konjac gel food needs to have high structural stability to ensure that it does not deform or separate water during storage and processing; at the same time, it should have moderate brittleness to simulate the breaking of cartilage during chewing; in addition, due to food safety and preservation needs, the gel should also have good antibacterial properties to extend the shelf life and reduce the risk of microbial contamination. The improvement of the above performance requirements not only helps to enhance the market competitiveness of the product, but also expands the application boundary of konjac gel in the fields of plant-based food, special nutritional food and functional food, etc. Therefore, systematic material design and process optimization around the structure regulation and function enhancement of konjac gel have become the key path to promote the high-quality development of this type of food.

[0003] At present, although there are various konjac-based gel food products and related technical solutions on the market, there are still certain limitations in meeting the demand for high-performance applications, especially in the improvement of stability, brittleness and antibacterial performance. For example, the Chinese patent with publication number CN114903159A discloses a production process for fresh bamboo shoot konjac instant food, which realizes efficient co-processing of bamboo shoot and konjac through a rinsing and dewatering device. The process has the advantages of simple operation, nutritional health, flavor retention and suitability for large-scale production. However, it still has problems such as loose gel structure and water separation under long-term storage or complex environment, indicating that its stability improvement is limited. For example, the patent with publication number CN109699974A discloses a konjac formula food, which proposes to adjust the taste of konjac gel by adding plasticizers such as flour and pueraria powder to enhance flexibility. However, this method often sacrifices brittleness, making it difficult to restore the true bone tissue fracture sensation. In addition, some patents attempt to achieve antibacterial function by adding natural plant extracts, but their antibacterial activity is limited by ingredient distribution and interfacial bonding force, resulting in unstable and short-lasting actual antibacterial effect. In summary, the existing technology has not yet made effective breakthroughs in material structure design and functional synergistic enhancement, making it difficult to meet the comprehensive demand for high stability, high brittleness and excellent antibacterial performance. Therefore, it is urgent to optimize the konjac gel system through new material modification methods and composite strategies to realize its wide application in high-end functional foods. SUMMARY

[0004] (1) Technical problems solved

[0005] The purpose of the present application is to provide a konjac gel food and its preparation method and application, which solves the problems of poor stability, insufficient brittleness and insufficient antibacterial performance of current konjac gel foods.

[0006] (2) Technical solutions

[0007] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] A konjac gel food, comprising the following raw materials by weight: 50.0-100.0 parts of phosphated konjac glucomannan, 25.0-40.0 parts of chitosan / microcrystalline cellulose composite filler, 2.0-6.0 parts of calcium chloride, 1.0-4.0 parts of trisodium citrate, 1.0-5.0 parts of citric acid, 1.0-3.0 parts of sodium trimetaphosphate, 2.0-8.0 parts of carrageenan, 2.0-6.0 parts of sodium alginate, 1.0-3.0 parts of calcium lactate, and 200.0-400.0 parts of deionized water.

[0009] The phosphated konjac glucomannan is obtained by drying and crushing the reaction product of konjac glucomannan and phosphate.

[0010] The chitosan / microcrystalline cellulose composite filler is composed of microcrystalline cellulose and chitosan particles loaded on the surface of the microcrystalline cellulose, and realizes the synergistic effect of stability enhancement and brittleness improvement through a multiple cross-linking network structure.

[0011] Further, the mass ratio of the microcrystalline cellulose to the chitosan of the chitosan / microcrystalline cellulose composite filler is (1.0~5.0):(0.5~2.0);

[0012] The average length of the particles of the chitosan / microcrystalline cellulose composite filler is 16~50μm, and the average diameter is 2.0~5.0μm.

[0013] Further, the mass ratio of the phosphorylated konjac glucomannan to the chitosan / microcrystalline cellulose composite filler is (1~4):(0.5~2);

[0014] The weight ratio of the carrageenan to the sodium alginate is (1~3):(1~2);

[0015] The weight ratio of the calcium chloride to the calcium lactate is (1~3):(0.5~1.5).

[0016] Further, the phosphate is sodium tripolyphosphate and sodium trimetaphosphate;

[0017] The phosphorylation degree of the phosphorylated konjac glucomannan is 0.04~0.20; the intermolecular hydrogen bond interaction and the ionic cross-linking effect are enhanced through the introduction of the phosphate groups.

[0018] The application adopts the design of synergistically constructing by phosphorylated konjac glucomannan and chitosan / microcrystalline cellulose composite filler, and is mainly used for enhancing the structural stability, brittleness performance and antibacterial performance of konjac gel food. The phosphate group is introduced by phosphate, so that the konjac glucomannan has good hydrogen bond formation ability and ion crosslinking ability, and stable electrostatic interaction occurs between the protonated amino groups of chitosan. At the same time, the phosphate group can also form hydrogen bonds with the hydroxyl groups of microcrystalline cellulose, and a multi-level crosslinking network structure composed of intramolecular hydrogen bonds, electrostatic crosslinking and calcium ion bridging is constructed. Microcrystalline cellulose provides a rigid support skeleton in the system, and chitosan acts as a flexible connecting unit, and the two together realize the synergistic enhancement of the spatial stability and mechanical properties of the network structure. Citric acid and its sodium salt adjust the pH of the system, further optimize the protonation state of chitosan, and regulate the charge distribution and crosslinking strength. On this basis, the cationic characteristics of chitosan endow the gel with good antibacterial function, and the protonated amino groups can combine with the bacterial cell wall through electrostatic interaction, interfere with its membrane structure and inhibit growth and reproduction; The granular distribution mode enhances the contact efficiency of the antibacterial components and microorganisms, so that the gel has sustained and stable antibacterial ability under normal temperature storage conditions. The synergistic system gives the gel multiple functions while constructing a stable network, effectively improves the texture performance, use safety and storage adaptability of the product, and meets the comprehensive needs of instant food for structural strength, taste level and microbial safety.

[0019] Further, the preparation method of the chitosan / microcrystalline cellulose composite filler is as follows: 20.0-50.0 parts by weight of chitosan is added to 500.0-1000.0 parts by weight of 0.5%-1.0% acetic acid aqueous solution, and mechanical stirring is carried out at a stirring rate of 300.0-500.0 rpm at room temperature 25.0±2.0 °C until complete dissolution to prepare a chitosan solution with a pH value of 3.8-4.2; then 100.0 parts of microcrystalline cellulose is added to deionized water, and a microcrystalline cellulose suspension is prepared by using a high-speed shearing dispersion machine at a rotation speed of 8000.0-12000.0 rpm for 15.0-30.0 min; then the pH value of the suspension is adjusted to 5.5-6.0 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added to the microcrystalline cellulose suspension at a dropping rate of 1.0-3.0 mL / min under continuous mechanical stirring; the pH value of the system is monitored in real time during the dropping process and maintained in the range of 5.8-6.2 by using a pH meter; after the dropping is completed, the chitosan is uniformly loaded by using a high-speed shearing dispersion at a rotation speed of 6000.0-8000.0 rpm for 1.0-2.0 h; then the mixture is centrifuged at a centrifugal rate of 3000.0-5000.0 rpm for 10.0-15.0 min, and the supernatant is discarded; the precipitate is washed repeatedly 2-3 times with deionized water until the filtrate is neutral; finally, the precipitate is dried in a vacuum freeze dryer at -50.0 to -40.0 °C for 12.0-24.0 h, and the target product is obtained after being crushed by a pulverizer and sieved through a standard sieve with a mesh size of 100-200.

[0020] Further, the preparation method of the microcrystalline cellulose is as follows: 100.0 parts by weight of cellulose raw material is uniformly mixed with 800.0-1200.0 parts by weight of 2.5-4.0 mol / L hydrochloric acid aqueous solution in a reactor with a condenser device, and mechanical stirring is carried out at a stirring rate of 200.0-400.0 rpm in an air atmosphere at normal pressure, while heating to a reaction temperature of 100.0-105.0 °C at a heating rate of 5.0-10.0 °C / min for reflux hydrolysis reaction for 2.0-4.0 h; after the reaction is completed, the system is cooled to room temperature 25.0±2.0 °C at a cooling rate of 3.0-5.0 °C / min; then the solid product is separated by filtration using a microporous filter membrane with a pore size of 0.45-0.65 μm; the solid product is washed repeatedly 5-8 times with deionized water until the pH value of the filtrate is 6.5-7.5; then the washed solid material is dried in a vacuum drying oven at 60.0-80.0 °C for 4.0-8.0 h; finally, the microcrystalline cellulose is obtained by using a high-speed shearing pulverizer at a rotation speed of 10000.0-15000.0 rpm for 30.0-60.0 min.

[0021] Further, the preparation method of the phosphorylated konjac glucomannan is as follows: 100.0 parts of konjac glucomannan is dispersed in 500.0-800.0 parts of deionized water, and a uniform colloid solution is prepared by mechanical stirring at a stirring rate of 300.0-500.0 rpm in an air atmosphere at normal pressure, while heating at a heating rate of 3.0-5.0 °C / min to a reaction temperature of 50.0-70.0 °C for 1.0-2.0 h, then 15.0-25.0 parts of sodium tripolyphosphate and 8.0-15.0 parts of sodium trimetaphosphate are added in sequence, the pH value of the system is adjusted to 6.8-7.2 with 0.1 mol / L sodium hydroxide aqueous solution, then the reaction system is heated to 90.0-95.0 °C at a heating rate of 5.0-8.0 °C / min, and the stirring rate is 200.0-400.0 rpm at the temperature, and the reaction is carried out for 3.0-5.0 h, the pH value is monitored in real time and kept stable during the reaction, after the reaction, the system is cooled to room temperature 25.0±2.0 °C, then an ethanol aqueous solution with a volume fraction of 85%-95% is added for alcohol precipitation separation, the precipitate is filtered through a microporous filter membrane with a pore size of 0.45-0.65 μm, and then washed with deionized water for 3-5 times until the filtrate is neutral, finally, the product is dried in a vacuum drying oven at 45.0-60.0 °C for 8.0-12.0 h, crushed by a pulverizer and sieved through a standard sieve with a mesh size of 120-200, to obtain the phosphorylated konjac glucomannan product.

[0022] The application further discloses a preparation method of the konjac gel food.

[0023] S1: accurately weighing each part of raw materials, adding the phosphorylated konjac glucomannan into deionized water, and mechanically stirring at 75-85 °C for 1-2 hours to prepare a uniform transparent colloid solution;

[0024] S2: adjusting the temperature of the colloid solution to 60-65 °C, adding the chitosan / microcrystalline cellulose composite filler, and treating by high-speed shearing dispersion technology for 10-30 minutes at a rotating speed of 4000-6000 revolutions / minute to ensure uniform dispersion of the filler, and then adding carrageenan and sodium alginate in sequence, and continuing to stir at high speed for 10-20 minutes until completely dissolved;

[0025] S3: adjusting the temperature of the system to 50-55 °C, adding calcium chloride, calcium lactate, citric acid, trisodium citrate and sodium trimetaphosphate in sequence, stirring for 5-10 minutes after adding each component, adjusting the final pH value to 6.5-7.0 with citric acid, to prepare a konjac gel precursor, and then placing the precursor in a vacuum environment for defoaming treatment for 10-20 minutes at a vacuum degree of -0.08 to -0.10 MPa to remove bubbles in the system;

[0026] S4: Pour the defoamed precursor into the pre-made mold, and let it stand at room temperature for 25-35 minutes for preliminary gelation, then place the initial gel product in a refrigerated environment at 2-6℃ for 2-4 hours for solidification, demold and cut into the desired size as needed to obtain the konjac gel food.

[0027] Further, the preparation process realizes the ordered construction of layered gel network through temperature gradient control, wherein the high temperature of 75-85℃ in step S1 promotes the full swelling of phosphorylated konjac glucomannan, the medium temperature of 60-65℃ in step S2 ensures the uniform dispersion of the composite filler and the dissolution of the polysaccharide component, the low temperature of 50-55℃ in step S3 avoids the thermal inactivation of the crosslinking agent, and the temperature gradient from room temperature to refrigeration temperature in step S4 realizes the gradual solidification and stabilization of the gel network.

[0028] The application also discloses an application of the konjac gel food in a simulated animal cartilage tissue taste food.

[0029] The preparation method of the konjac gel food disclosed in the application aims to realize the efficient construction of the konjac gel food with uniform structure, stable performance and good sensory quality by precisely controlling the adding sequence, temperature conditions and dispersion state of each component. The method realizes the ordered transition from the solution state to the stable gel network through setting the temperature gradient at different stages, aiming at the swelling characteristics of phosphorylated konjac glucomannan, the dispersion characteristics of the chitosan / microcrystalline cellulose composite filler and the dissolution and crosslinking conditions of various gel auxiliary components. In the first stage, the high temperature treatment helps the phosphorylated konjac glucomannan to fully expand the molecular chain and form a uniform colloidal solution, providing a basis for subsequent network construction; under the medium temperature condition, the shear dispersion of the composite filler and the sufficient dissolution of the polysaccharide component ensure the uniformity and integrity of the gel skeleton; the low temperature stage effectively avoids the inactivation of the crosslinking agent at high temperature, and optimizes the action efficiency of the ionic crosslinking components such as calcium ions and sodium trimetaphosphate; finally, through the temperature progression process from room temperature to refrigeration, the gel system is gradually solidified in a relatively mild environment, forming a stable three-dimensional network structure. Through the systematic coordination of the process parameters at each stage, the method not only improves the structural compactness and rheological resistance of the gel, but also enhances its performance in simulating the taste of animal cartilage tissue, providing a feasible process path for the development and application of konjac-based functional food.

[0030] (3) Beneficial technical effects

[0031] 1. The application precisely matches the multi-component synergy and temperature control process, significantly improves the structural stability and biomimetic taste of the konjac gel, solves the problems of poor brittleness and weak processing adaptability of the existing gel, and is suitable for the development of high-end plant-based food.

[0032] 2. The present application realizes konjac gel food with stable structure and excellent taste by component synergy and temperature control process optimization, effectively solves the problems of poor brittleness and weak stability of existing products, is suitable for various bionic food scenes, and has significant application and promotion value. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Morphology diagram of microcrystalline cellulose prepared for the present application embodiment 1.

[0034] Figure 2 XRD phase analysis diagram of microcrystalline cellulose prepared for the present application embodiment 1.

[0035] Figure 3 Morphology diagram of chitosan / microcrystalline cellulose composite filler prepared for the present application embodiment 1.

[0036] Figure 4 XRD phase analysis diagram of chitosan / microcrystalline cellulose composite filler prepared for the present application embodiment 1.

[0037] Figure 5 Microstructure morphology diagram of konjac gel food prepared for the present application embodiment 1.

[0038] Figure 6 Actual object diagram of triangle chicken crisp bone konjac gel food prepared for the present application embodiment 1.

[0039] Figure 7 Storage modulus and fracture strength comparison diagram of the present application embodiment and comparative example.

[0040] Figure 8 Brittleness index and water separation rate relationship comparison diagram of the present application embodiment and comparative example.

[0041] Figure 9 Storage modulus and antibacterial performance correlation comparison diagram of the present application embodiment and comparative example.

[0042] Figure 10 Antibacterial circle diameter comparison diagram of the present application embodiment and comparative example. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present application embodiment clearer, the technical scheme in the present application embodiment will be described clearly and completely below in combination with the drawings in the present application embodiment.

[0044] Embodiment 1

[0045] A konjac gel food includes the following raw materials in parts by weight: 50.0 parts of phosphorylated konjac glucomannan, 25.0 parts of chitosan / microcrystalline cellulose composite filler, 2.0 parts of calcium chloride, 1.0 part of trisodium citrate, 1.0 part of citric acid, 1.0 part of sodium trimetaphosphate, 2.0 parts of carrageenan, 2.0 parts of sodium alginate, 1.0 part of calcium lactate, and 200.0 parts of deionized water;

[0046] The phosphorylated konjac glucomannan is obtained by drying and crushing after konjac glucomannan is reacted with a phosphate salt; the chitosan / microcrystalline cellulose composite filler is composed of microcrystalline cellulose and chitosan particles loaded on the surface of the microcrystalline cellulose, and achieves a synergistic effect of stability enhancement and brittleness improvement through a multiple cross-linking network structure.

[0047] The mass ratio of the microcrystalline cellulose to the chitosan of the chitosan / microcrystalline cellulose composite filler of the present embodiment is 3.45:1;

[0048] The average length of the particles of the chitosan / microcrystalline cellulose composite filler is 16 μm, and the average diameter is 2.0 μm.

[0049] The phosphate salt of the present embodiment is sodium tripolyphosphate and sodium trimetaphosphate;

[0050] The phosphorylation degree of the phosphorylated konjac glucomannan of the present embodiment is 0.09; the intermolecular hydrogen bond interaction and the ionic cross-linking effect are enhanced through the introduction of phosphate groups.

[0051] The preparation method of the chitosan / microcrystalline cellulose composite filler of the present embodiment is as follows: 29 parts of chitosan are added into 650 parts of 0.6% acetic acid aqueous solution, and mechanical stirring is carried out at a stirring rate of 360 rpm at room temperature 25.0±2.0°C for 0.9 h until complete dissolution to prepare a chitosan solution with a pH value of 3.9, then 100.0 parts of microcrystalline cellulose are added into deionized water, and a microcrystalline cellulose suspension is prepared by using a high-speed shearing dispersion machine at a rotating speed of 9200 rpm for 19.5 min, then the pH value of the suspension is adjusted to 5.6 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added into the microcrystalline cellulose suspension at a dropping speed of 1.6 mL / min under the condition of continuous mechanical stirring, the pH value of the system is monitored in real time and maintained in the range of 5.9 by using a pH meter during the dropping process, after the dropping is completed, the chitosan is uniformly loaded by using high-speed shearing dispersion at 6600 rpm for 1.3 h, then the mixture is centrifuged at a centrifugal rate of 3600 rpm for 11.5 min, the supernatant is discarded, and the precipitate is washed twice with deionized water until the filtrate is neutral, finally the precipitate is dried in a vacuum freeze dryer at -47°C for 15.6 h, and the target product is obtained after crushing by a crusher and passing through a 130-mesh standard sieve.

[0052] The preparation method of the microcrystalline cellulose of the present embodiment is as follows: 100.0 parts of cellulose raw material is uniformly mixed with 920 parts of 2.9 mol / L hydrochloric acid aqueous solution in a reactor with a condenser device, mechanical stirring is carried out at a stirring rate of 260 rpm in an air atmosphere at normal pressure, heating is carried out at a heating rate of 6.5°C / min to a reaction temperature of 101.5°C, and reflux hydrolysis reaction is carried out for 2.6 h; after the reaction is completed, the system is cooled to room temperature 25.0±2.0°C at a cooling rate of 3.6°C / min, then filtration separation is carried out by using a microporous filter membrane with a pore size of 0.51 μm, the solid product is washed repeatedly with deionized water for 6 times until the pH value of the filtrate is 6.8, then the washed solid material is placed in a vacuum drying oven and vacuum dried at 66°C for 5.2 h, finally, a high-speed shearing pulverizer is used to treat at a speed of 11500 rpm for 39 min to obtain the microcrystalline cellulose.

[0053] The preparation method of the phosphated konjac glucomannan of the present embodiment is as follows: 100.0 parts of konjac glucomannan is dispersed in 590 parts of deionized water, mechanical stirring is carried out at a stirring rate of 360 rpm in an air atmosphere at normal pressure, and a uniform colloidal solution is prepared by heating at a heating rate of 3.6°C / min to a reaction temperature of 56°C for 1.3 h; then 18 parts of sodium tripolyphosphate and 10.1 parts of sodium trimetaphosphate are added in sequence, the pH value of the system is adjusted to 6.9 by using 0.1 mol / L sodium hydroxide aqueous solution, then the reaction system is heated to 91.5°C at a heating rate of 5.9°C / min, and reaction is carried out at a stirring rate of 260 rpm for 3.6 h at the temperature; the pH value is monitored in real time and kept stable during the reaction, after the reaction is completed, the system is cooled to room temperature 25.0±2.0°C, then alcohol precipitation separation is carried out by adding an 88% volume fraction of ethanol aqueous solution, the precipitate is filtered by using a microporous filter membrane with a pore size of 0.51 μm, and then washed with deionized water for 4 times until the filtrate is neutral; finally, the product is placed in a vacuum drying oven and dried at 49.5°C for 9.2 h, and then crushed by a pulverizer and passed through a 144-mesh standard sieve to prepare the phosphated konjac glucomannan product.

[0054] The preparation method of the konjac gel food of the present embodiment comprises the following steps:

[0055] S1: accurately weighing each part of the raw material, adding the phosphated konjac glucomannan into deionized water, and mechanically stirring at 78°C for 1.3 hours to prepare a uniform transparent colloidal solution;

[0056] S2: The temperature of the colloidal solution is adjusted to 62℃, and the chitosan / microcrystalline cellulose composite filler is added, and is treated by high-speed shearing dispersion technology for 16 minutes at a speed of 4600 revolutions per minute to ensure uniform dispersion of the filler, and then carrageenan and sodium alginate are sequentially added, and high-speed stirring is continued for 13 minutes until complete dissolution;

[0057] S3: The temperature of the system is adjusted to 52℃, and calcium chloride, calcium lactate, citric acid, trisodium citrate, and sodium trimetaphosphate are sequentially added, and stirring is performed for 6.5 minutes after each component is added, and the final pH value is adjusted to 6.6 by citric acid to obtain a konjac gel precursor, and then the precursor is placed in a vacuum environment for defoaming treatment for 13 minutes at a vacuum degree of -0.086 MPa to remove bubbles in the system;

[0058] S4: The defoamed precursor is poured into a pre-prepared mold, and is left to stand at room temperature for 28 minutes for preliminary gelation, and then the preliminary gelation product is placed in a refrigeration environment at 3.2℃ for solidification for 2.6 hours, and is demolded and cut into a predetermined size as needed to obtain the konjac gel food.

[0059] In the embodiment, the ordered construction of the layered gel network is achieved by temperature gradient control, in which the high temperature of 78℃ in step S1 promotes sufficient swelling of the phosphorylated konjac glucomannan, the medium temperature of 62℃ in step S2 ensures uniform dispersion of the composite filler and dissolution of the polysaccharide components, the low temperature of 52℃ in step S3 avoids thermal inactivation of the cross-linking agent, and the temperature gradient from room temperature to refrigeration temperature in step S4 achieves gradual solidification and stabilization of the gel network.

[0060] Example 2

[0061] A konjac gel food includes the following raw materials in parts by weight: 65 parts of phosphorylated konjac glucomannan, 30 parts of chitosan / microcrystalline cellulose composite filler, 3 parts of calcium chloride, 2 parts of trisodium citrate, 2 parts of citric acid, 2 parts of sodium trimetaphosphate, 4 parts of carrageenan, 3 parts of sodium alginate, 2 parts of calcium lactate, and 260 parts of deionized water.

[0062] The phosphorylated konjac glucomannan is obtained by drying and crushing after reaction of konjac glucomannan with a phosphate; the chitosan / microcrystalline cellulose composite filler is composed of microcrystalline cellulose and chitosan particles loaded on the surface of the microcrystalline cellulose, and achieves a synergistic effect of stability enhancement and brittleness improvement by a multiple cross-linking network structure.

[0063] The mass ratio of the microcrystalline cellulose to chitosan of the chitosan / microcrystalline cellulose composite filler in the embodiment is 5.0:1.0;

[0064] The average length of the particles of the chitosan / microcrystalline cellulose composite filler is 26 μm, and the average diameter is 2.9 μm. The phosphate in the embodiment is sodium tripolyphosphate and sodium trimetaphosphate.

[0065] The phosphorylation degree of the phosphorylated konjac glucomannan of the present embodiment is 0.04; the intermolecular hydrogen bond interaction and ionic crosslinking effect are enhanced by the introduction of phosphate groups.

[0066] The preparation method of the chitosan / microcrystalline cellulose composite filler of the present embodiment is as follows: 20.0 parts of chitosan is added into 500.0 parts of 0.5% acetic acid aqueous solution, and mechanical stirring is carried out at a stirring rate of 300.0 rpm at room temperature 25.0±2.0°C until complete dissolution to prepare a chitosan solution with a pH value of 3.8, then 100.0 parts of microcrystalline cellulose is added into deionized water, and a microcrystalline cellulose suspension is prepared by using a high-speed shearing dispersion machine at a rotation speed of 8000.0 rpm for 15.0 min, then the pH value of the suspension is adjusted to 5.5 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added into the microcrystalline cellulose suspension at a dropping speed of 1.0 mL / min under continuous mechanical stirring, the pH value of the system is monitored in real time and maintained within the range of 5.8 by using a pH meter during the dropping process, after the dropping is completed, the chitosan is uniformly loaded by using a high-speed shearing dispersion at 6000.0 rpm for 1.0 h, then the mixture is centrifuged at a centrifugal rate of 3000.0 rpm for 10.0 min, the supernatant is discarded, and the precipitate is washed with deionized water for 2 times until the filtrate is neutral, finally the precipitate is dried in a vacuum freeze dryer at -50.0°C for 12.0 h, and then crushed by a pulverizer and sieved through a 100-mesh standard sieve to obtain the target product.

[0067] The preparation method of the microcrystalline cellulose of the present embodiment is as follows: 100.0 parts of cellulose raw material is uniformly mixed with 800.0 parts of 2.5 mol / L hydrochloric acid aqueous solution in a reactor with a condenser, mechanical stirring is carried out at a stirring rate of 200.0 rpm in an air atmosphere at normal pressure, and the system is heated to a reflux hydrolysis reaction temperature of 100.0°C at a heating rate of 5.0°C / min, and then cooled to room temperature 25.0±2.0°C at a cooling rate of 3.0°C / min after the reaction is completed, then the system is filtered and separated by using a microporous filter membrane with a pore size of 0.45 μm, the solid product is washed with deionized water for 5 times until the pH value of the filtrate is 6.5, then the washed solid material is placed in a vacuum drying oven at 60.0°C for vacuum drying for 4.0 h, and finally the high-speed shearing pulverizer is used to treat at a rotation speed of 10000.0 rpm for 30.0 min to obtain the microcrystalline cellulose.

[0068] The preparation method of the phosphorylated konjac glucomannan of the present embodiment is as follows: 100.0 parts of konjac glucomannan is dispersed in 500.0 parts of deionized water, and a uniform colloid solution is prepared by mechanical stirring at a stirring rate of 300.0 rpm in an air atmosphere at normal pressure, while heating at a heating rate of 3.0°C / min to a reaction temperature of 50.0°C for 1.0 h, then 15.0 parts of sodium tripolyphosphate and 8.0 parts of sodium trimetaphosphate are added in sequence, the pH value of the system is adjusted to 6.8 with 0.1 mol / L sodium hydroxide aqueous solution, then the reaction system is heated to 90.0°C at a heating rate of 5.0°C / min, and the reaction is carried out at a stirring rate of 200.0 rpm for 3.0 h at the temperature, the pH value is monitored in real time and kept stable during the reaction, after the reaction is completed, the system is cooled to room temperature 25.0±2.0°C, then an alcohol aqueous solution with a volume fraction of 85% is added for alcohol precipitation separation, the precipitate is filtered through a microporous filter membrane with a pore size of 0.45 μm, then washed with deionized water for 3 times until the filtrate is neutral, finally the product is dried in a vacuum drying oven at 45.0°C for 8.0 h, crushed by a pulverizer and sieved through a standard sieve of 120 meshes to obtain the phosphorylated konjac glucomannan product.

[0069] The preparation method of a konjac gel food of the present embodiment comprises the following steps:

[0070] S1: accurately weigh each part of the raw materials, add the phosphorylated konjac glucomannan into deionized water, and mechanically stir at 75°C for 1 hour to prepare a uniform transparent colloid solution;

[0071] S2: adjust the temperature of the colloid solution to 60°C, add the chitosan / microcrystalline cellulose composite filler, and treat it by high-speed shearing dispersion technology for 10 minutes at a speed of 4000 revolutions / minute to ensure uniform dispersion of the filler, then add carrageenan and sodium alginate in sequence, and continue to stir at high speed for 10 minutes until completely dissolved;

[0072] S3: adjust the temperature of the system to 50°C, add calcium chloride, calcium lactate, citric acid, trisodium citrate and sodium trimetaphosphate in sequence, stir for 5 minutes after adding each component, and adjust the final pH value to 6.5 with citric acid to prepare a konjac gel precursor, then place the precursor in a vacuum environment for defoaming treatment for 10 minutes at a vacuum degree of -0.08 MPa to remove the bubbles in the system;

[0073] S4: pour the defoamed precursor into a pre-prepared mold, and stand still at room temperature for 25 minutes for preliminary gelation, then place the primary gel product in a 2°C refrigeration environment for solidification for 2 hours, demold and cut into a predetermined size as needed to prepare the konjac gel food.

[0074] The present embodiment realizes the ordered construction of the layered gel network through temperature gradient control, wherein the high temperature of 75℃ in step S1 promotes the full swelling of the phosphorylated konjac glucomannan, the medium temperature of 60℃ in step S2 ensures the uniform dispersion of the composite filler and the dissolution of the polysaccharide component, the low temperature of 50℃ in step S3 avoids the thermal inactivation of the crosslinking agent, and the temperature gradient from room temperature to cold storage temperature in step S4 realizes the gradual solidification and stabilization of the gel network.

[0075] Embodiment 3

[0076] A konjac gel food, comprising the following raw materials in parts by weight: 100.0 parts of phosphorylated konjac glucomannan, 50.0 parts of chitosan / microcrystalline cellulose composite filler, 6.0 parts of calcium chloride, 4.0 parts of trisodium citrate, 5.0 parts of citric acid, 3.0 parts of sodium trimetaphosphate, 8.0 parts of carrageenan, 6.0 parts of sodium alginate, 3.0 parts of calcium lactate, and 400.0 parts of deionized water.

[0077] The phosphorylated konjac glucomannan is obtained by drying and crushing after the reaction of konjac glucomannan and phosphate; the chitosan / microcrystalline cellulose composite filler is composed of microcrystalline cellulose and chitosan particles loaded on the surface of the microcrystalline cellulose, and realizes the synergistic effect of stability enhancement and brittleness improvement through the multiple crosslinking network structure.

[0078] The mass ratio of the microcrystalline cellulose to chitosan of the chitosan / microcrystalline cellulose composite filler of the present embodiment is 2.0:1;

[0079] The average length of the particles of the chitosan / microcrystalline cellulose composite filler is 50μm, and the average diameter is 5.0μm.

[0080] The phosphate of the present embodiment is sodium tripolyphosphate and sodium trimetaphosphate;

[0081] The phosphorylation degree of the phosphorylated konjac glucomannan of the present embodiment is 0.20; the intermolecular hydrogen bond interaction and ionic crosslinking effect are enhanced through the introduction of phosphate groups.

[0082] The preparation method of the chitosan / microcrystalline cellulose composite filler of the present embodiment is as follows: 50.0 parts of chitosan is added into 1000.0 parts of 1.0% acetic acid aqueous solution, and mechanical stirring is carried out at a stirring rate of 500.0 rpm for 2.0 h at room temperature 25.0±2.0°C until complete dissolution to prepare a chitosan solution with a pH value of 4.2, then 100.0 parts of microcrystalline cellulose is added into deionized water, and a microcrystalline cellulose suspension is prepared by using a high-speed shearing dispersion machine at a rotation speed of 12000.0 rpm for 30.0 min, then the pH value of the suspension is adjusted to 6.0 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added into the microcrystalline cellulose suspension at a dropping rate of 3.0 mL / min under continuous mechanical stirring, the pH value of the system is monitored in real time and maintained in the range of 6.2 during the dropping process, after the dropping is completed, the chitosan is uniformly loaded by using high-speed shearing dispersion at 8000.0 rpm for 2.0 h, then the mixture is centrifuged at a centrifugal rate of 5000.0 rpm for 15.0 min, the supernatant is discarded, and the precipitate is washed with deionized water for 3 times until the filtrate is neutral, finally the precipitate is dried in a vacuum freeze dryer at -40.0°C for 24.0 h, and then crushed by a pulverizer and sieved through a 200-mesh standard sieve to obtain the target product.

[0083] The preparation method of the microcrystalline cellulose of the present embodiment is as follows: 100.0 parts of cellulose raw material is uniformly mixed with 1200.0 parts of 4.0 mol / L hydrochloric acid aqueous solution in a reactor with a condenser device, mechanical stirring is carried out at a stirring rate of 400.0 rpm in an air atmosphere at normal pressure, and the system is heated to a reaction temperature of 105.0°C at a heating rate of 10.0°C / min for reflux hydrolysis reaction for 4.0 h, after the reaction is completed, the system is cooled to room temperature 25.0±2.0°C at a cooling rate of 5.0°C / min, then the solid product is separated by filtration using a microporous filter membrane with a pore size of 0.65 μm, and the solid material is washed with deionized water for 8 times until the pH value of the filtrate is 7.5, then the washed solid material is placed in a vacuum drying oven at 80.0°C for vacuum drying for 8.0 h, finally the high-speed shearing pulverizer is used to treat at a rotation speed of 15000.0 rpm for 60.0 min to obtain the microcrystalline cellulose.

[0084] The preparation method of the phosphorylated konjac glucomannan of the present embodiment is as follows: 100.0 parts of konjac glucomannan is dispersed in 800.0 parts of deionized water, and a uniform colloid solution is prepared by mechanical stirring at a stirring rate of 500.0 rpm in an air atmosphere at normal pressure, while heating at a heating rate of 5.0°C / min to a reaction temperature of 70.0°C for 2.0 h, then 25.0 parts of sodium tripolyphosphate and 15.0 parts of sodium trimetaphosphate are added in sequence, the pH value of the system is adjusted to 7.2 with 0.1 mol / L sodium hydroxide aqueous solution, then the reaction system is heated to 95.0°C at a heating rate of 8.0°C / min, and the reaction is carried out at a stirring rate of 400.0 rpm for 5.0 h at the temperature, the pH value is monitored in real time and kept stable during the reaction, after the reaction is completed, the system is cooled to room temperature 25.0±2.0°C, then alcohol precipitation separation is carried out with 95% by volume ethanol aqueous solution, the precipitate is filtered through a microporous filter membrane with a pore size of 0.65 μm, then washed with deionized water for 5 times until the filtrate is neutral, finally the product is dried in a vacuum drying oven at 60.0°C for 12.0 h, crushed by a pulverizer and sieved through a standard sieve of 200 meshes to obtain the phosphorylated konjac glucomannan product.

[0085] The preparation method of a konjac gel food of the present embodiment comprises the following steps:

[0086] S1: accurately weigh each part of the raw materials, add the phosphorylated konjac glucomannan into deionized water, and mechanically stir at 85°C for 2 hours to prepare a uniform transparent colloid solution;

[0087] S2: adjust the temperature of the colloid solution to 65°C, add the chitosan / microcrystalline cellulose composite filler, and treat with high-speed shearing dispersion technology for 30 minutes at a speed of 6000 revolutions / minute to ensure uniform dispersion of the filler, then add carrageenan and sodium alginate in sequence, and continue to stir at high speed for 20 minutes until completely dissolved;

[0088] S3: adjust the temperature of the system to 55°C, add calcium chloride, calcium lactate, citric acid, trisodium citrate and sodium trimetaphosphate in sequence, stir for 10 minutes after adding each component, and adjust the final pH value to 7.0 with citric acid to prepare a konjac gel precursor, then place the precursor in a vacuum environment for defoaming treatment for 20 minutes at a vacuum degree of -0.10 MPa to remove the bubbles in the system;

[0089] S4: pour the defoamed precursor into a pre-prepared mold, stand at room temperature for 35 minutes for preliminary gelation, then place the primary gel product in a 6°C refrigeration environment for solidification for 4 hours, demold and cut into a predetermined size as needed to prepare the konjac gel food.

[0090] The present embodiment realizes the ordered construction of layered gel network through temperature gradient control, wherein the high temperature of 85℃ in step S1 promotes the full swelling of phosphorylated konjac glucomannan, the medium temperature of 65℃ in step S2 ensures the uniform dispersion of the composite filler and the dissolution of the polysaccharide component, the low temperature of 55℃ in step S3 avoids the thermal inactivation of the crosslinking agent, and the temperature gradient from room temperature to cold storage temperature in step S4 realizes the gradual solidification and stabilization of the gel network.

[0091] Embodiment 4

[0092] A konjac gel food, comprising the following raw materials in parts by weight: 100.0 parts of phosphorylated konjac glucomannan, 40.0 parts of chitosan / microcrystalline cellulose composite filler, 6.0 parts of calcium chloride, 4.0 parts of trisodium citrate, 5.0 parts of citric acid, 3.0 parts of sodium trimetaphosphate, 8.0 parts of carrageenan, 6.0 parts of sodium alginate, 3.0 parts of calcium lactate, and 400.0 parts of deionized water.

[0093] The phosphorylated konjac glucomannan is obtained by drying and crushing after the reaction of konjac glucomannan and phosphate; the chitosan / microcrystalline cellulose composite filler is composed of microcrystalline cellulose and chitosan particles loaded on the surface of the microcrystalline cellulose, and realizes the synergistic effect of stability enhancement and brittleness improvement through the multiple crosslinking network structure.

[0094] The mass ratio of microcrystalline cellulose to chitosan of the chitosan / microcrystalline cellulose composite filler of the present embodiment is 2.63:1.0;

[0095] The average length of the particles of the chitosan / microcrystalline cellulose composite filler is 50μm, and the average diameter is 5.0μm.

[0096] The phosphate of the present embodiment is sodium tripolyphosphate and sodium trimetaphosphate;

[0097] The phosphorylation degree of the phosphorylated konjac glucomannan of the present embodiment is 0.14; the intermolecular hydrogen bond interaction and ionic crosslinking effect are enhanced through the introduction of phosphate groups.

[0098] The preparation method of the chitosan / microcrystalline cellulose composite filler of the present embodiment is as follows: 38 parts of chitosan is added into 800 parts of 0.8% acetic acid aqueous solution by weight, and is mechanically stirred at a stirring rate of 420 rpm at room temperature of 25.0±2.0°C for 1.4 h until completely dissolved to prepare a chitosan solution with a pH value of 4.0. Then, 100.0 parts of microcrystalline cellulose is added into deionized water, and is dispersed by a high-speed shearing dispersion machine at a rotating speed of 10400 rpm for 24 min to prepare a microcrystalline cellulose suspension. Then, the pH value of the suspension is adjusted to 5.8 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added into the microcrystalline cellulose suspension at a dropping speed of 2.2 mL / min under continuous mechanical stirring. The pH value of the system is monitored in real time by using a pH meter during the dropping process and is maintained within the range of 6.0. After the dropping process is completed, the chitosan is uniformly loaded by using a high-speed shearing dispersion treatment at 7200 rpm for 1.6 h. Then, the mixture is centrifuged at a centrifugal rate of 4200 rpm for 13 min, and the supernatant is discarded. The precipitate is washed with deionized water for 3 times until the filtrate is neutral. Finally, the precipitate is dried in a vacuum freeze dryer at -43°C for 19.2 h, is crushed by a crusher, and is passed through a 160-mesh standard sieve to obtain the target product.

[0099] The preparation method of the microcrystalline cellulose of the present embodiment is as follows: 100.0 parts of cellulose raw material is uniformly mixed with 1040 parts of 3.4 mol / L hydrochloric acid aqueous solution in a reactor with a condenser device, and is mechanically stirred at a stirring rate of 320 rpm in an air atmosphere at normal pressure. Meanwhile, the system is heated to a reaction temperature of 103°C at a heating rate of 8°C / min for a reflux hydrolysis reaction of 3.2 h. After the reaction is completed, the system is cooled to room temperature of 25.0±2.0°C at a cooling rate of 4.2°C / min. Then, the system is filtered and separated by using a microporous filter membrane with a pore size of 0.57 μm. The solid product is washed with deionized water for 7 times until the pH value of the filtrate is 7.1. Then, the washed solid material is placed in a vacuum drying oven at 72°C for vacuum drying for 6.4 h. Finally, the microcrystalline cellulose is obtained by using a high-speed shearing crusher at a rotating speed of 13000 rpm for 48 min.

[0100] The preparation method of the phosphorylated konjac glucomannan of the present embodiment is as follows: 100.0 parts of konjac glucomannan is dispersed in 680 parts of deionized water, and a uniform colloid solution is prepared by mechanical stirring at a stirring rate of 420 rpm in an air atmosphere at normal pressure, while heating at a heating rate of 4.2°C / min to a reaction temperature of 62°C for 1.6 h, then 21 parts of sodium tripolyphosphate and 12.2 parts of sodium trimetaphosphate are added in sequence, the pH value of the system is adjusted to 7.0 with 0.1 mol / L sodium hydroxide aqueous solution, then the reaction system is heated to 93°C at a heating rate of 6.8°C / min, and reacted at a stirring rate of 320 rpm for 4.2 h at this temperature, the pH value is monitored in real time during the reaction and kept stable, after the reaction is completed, the system is cooled to room temperature 25.0±2.0°C, then an alcohol aqueous solution with a volume fraction of 91% is added for alcohol precipitation separation, the precipitate is filtered through a microporous filter membrane with a pore size of 0.57 μm, then washed with deionized water for 4 times until the filtrate is neutral, finally the product is dried in a vacuum drying oven at 54°C for 10.4 h, crushed by a pulverizer and sieved through a standard sieve of 168 meshes to obtain the phosphorylated konjac glucomannan product.

[0101] The preparation method of a konjac gel food of the present embodiment comprises the following steps:

[0102] S1: accurately weigh each part of the raw materials, add the phosphorylated konjac glucomannan into deionized water, and mechanically stir at 81°C for 1.6 hours to prepare a uniform transparent colloid solution;

[0103] S2: adjust the temperature of the colloid solution to 63°C, add the chitosan / microcrystalline cellulose composite filler, and treat it by high-speed shearing dispersion technology for 22 minutes at a speed of 5200 revolutions / minute to ensure uniform dispersion of the filler, then add carrageenan and sodium alginate in sequence, and continue to stir at high speed for 16 minutes until completely dissolved;

[0104] S3: adjust the temperature of the system to 53°C, add calcium chloride, calcium lactate, citric acid, trisodium citrate and sodium trimetaphosphate in sequence, stir for 8 minutes after adding each component, and adjust the final pH value to 6.8 with citric acid to prepare a konjac gel precursor, then place the precursor in a vacuum environment for defoaming treatment for 16 minutes at a vacuum degree of -0.092 MPa to remove the gas bubbles in the system;

[0105] S4: pour the defoamed precursor into a pre-made mold, stand still at room temperature for 31 minutes for preliminary gelation, then place the primary gel product in a 4.4°C refrigeration environment for solidification for 3.2 hours, demold and cut into the predetermined size as needed to prepare the konjac gel food.

[0106] The present embodiment realizes the ordered construction of layered gel network through temperature gradient control, wherein the high temperature of 81℃ in step S1 promotes the full swelling of phosphorylated konjac glucomannan, the medium temperature of 63℃ in step S2 ensures the uniform dispersion of the composite filler and the dissolution of the polysaccharide component, the low temperature of 53℃ in step S3 avoids the thermal inactivation of the crosslinking agent, and the temperature gradient from room temperature to cold storage temperature in step S4 realizes the gradual solidification and stabilization of the gel network.

[0107] Comparative Example 1

[0108] The same as Example 1 basically, the difference lies in that the phosphorylated konjac glucomannan is not used, but the ordinary konjac glucomannan 50.0 parts without phosphorylation treatment is directly used, the sodium tripolyphosphate and sodium trimetaphosphate are not added, and the rest of the components and the amount remain unchanged.

[0109] Comparative Example 2

[0110] The same as Example 1 basically, the difference lies in that the chitosan / microcrystalline cellulose composite filler is not used, but only the microcrystalline cellulose 25.0 parts is used as the filler, the chitosan particles loaded on the surface of the microcrystalline cellulose are not contained, and the rest of the components and the amount remain unchanged.

[0111] Comparative Example 3

[0112] The same as Example 1 basically, the difference lies in that the mass ratio of the microcrystalline cellulose to the chitosan of the chitosan / microcrystalline cellulose composite filler is 10.0:0.2, and the rest of the preparation process and the component amount remain unchanged.

[0113] The preparation method of the chitosan / microcrystalline cellulose composite filler of the present comparative example is as follows: 2 parts of chitosan is added into 650 parts of 0.6% acetic acid aqueous solution in terms of weight fraction, and is mechanically stirred at a stirring rate of 360 rpm at room temperature of 25.0±2.0°C for 0.9 h until completely dissolved to prepare a chitosan solution with a pH value of 3.9, then 100.0 parts of microcrystalline cellulose is added into deionized water, and is dispersed by a high-speed shearing dispersion machine at a rotating speed of 9200 rpm for 19.5 min to prepare a microcrystalline cellulose suspension, then the pH value of the suspension is adjusted to 5.6 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added into the microcrystalline cellulose suspension at a dropping speed of 1.6 mL / min under the condition of continuous mechanical stirring, the pH value of the system is monitored in real time and maintained in the range of 5.9 by using a pH meter during the dropping process, after the dropping is completed, the chitosan is uniformly loaded by using high-speed shearing dispersion at 6600 rpm for 1.3 h, then the mixture is centrifuged at a centrifugal rate of 3600 rpm for 11.5 min, the supernatant is discarded, and the precipitate is washed twice with deionized water until the filtrate is neutral, finally, the precipitate is dried in a vacuum freeze dryer at -47°C for 15.6 h, and is crushed by a crusher and then sieved through a 130-mesh standard sieve to obtain the target product.

[0114] Comparative Example 4

[0115] The preparation method of the chitosan / microcrystalline cellulose composite filler of the present comparative example is as follows: 2 parts of chitosan is added into 650 parts of 0.6% acetic acid aqueous solution in terms of weight fraction, and is mechanically stirred at a stirring rate of 360 rpm at room temperature of 25.0±2.0°C for 0.9 h until completely dissolved to prepare a chitosan solution with a pH value of 3.9, then 100.0 parts of microcrystalline cellulose is added into deionized water, and is dispersed by a high-speed shearing dispersion machine at a rotating speed of 9200 rpm for 19.5 min to prepare a microcrystalline cellulose suspension, then the pH value of the suspension is adjusted to 5.6 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added into the microcrystalline cellulose suspension at a dropping speed of 1.6 mL / min under the condition of continuous mechanical stirring, the pH value of the system is monitored in real time and maintained in the range of 5.9 by using a pH meter during the dropping process, after the dropping is completed, the chitosan is uniformly loaded by using high-speed shearing dispersion at 6600 rpm for 1.3 h, then the mixture is centrifuged at a centrifugal rate of 3600 rpm for 11.5 min, the supernatant is discarded, and the precipitate is washed twice with deionized water until the filtrate is neutral, finally, the precipitate is dried in a vacuum freeze dryer at -47°C for 15.6 h, and is crushed by a crusher and then sieved through a 130-mesh standard sieve to obtain the target product.

[0116] The preparation method of the chitosan / microcrystalline cellulose composite filler in the present comparative example is as follows: 29 parts of chitosan is added into 650 parts of 0.6% acetic acid aqueous solution, and mechanical stirring is carried out at a stirring rate of 360 rpm at room temperature of 25.0±2.0°C for 0.9 h until complete dissolution to prepare a chitosan solution with a pH value of 3.9. Then, 100.0 parts of microcrystalline cellulose is added into deionized water, and a microcrystalline cellulose suspension is prepared by using a high-speed shearing dispersion machine at a rotating speed of 9200 rpm for 19.5 min. Subsequently, the pH value of the suspension is adjusted to 5.6 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added into the microcrystalline cellulose suspension at a dropping speed of 1.6 mL / min under continuous mechanical stirring. The pH value of the system is monitored in real time by using a pH meter during the dropping process and is maintained within the range of 5.9. After the dropping is completed, the chitosan is uniformly loaded by using high-speed shearing dispersion at 6600 rpm for 1.3 h. Then, the mixture is centrifuged at a centrifugal rate of 3600 rpm for 11.5 min, and the supernatant is discarded. The precipitate is washed twice with deionized water until the filtrate is neutral. Finally, the precipitate is dried in a vacuum freeze dryer at -47°C for 15.6 h, and the target product with an average length of 80 μm and an average diameter of 8.0 μm is obtained by using a pulverizer for crushing and sieving.

[0117] The preparation method of the microcrystalline cellulose in the present comparative example is the same as that in Example 1.

[0118] Comparative Example 5

[0119] The present comparative example is basically the same as Example 1, except that the mass ratio of the phosphated konjac glucomannan to the chitosan / microcrystalline cellulose composite filler is 6:0.3.

[0120] Comparative Example 6

[0121] The present comparative example is basically the same as Example 1, except that the degree of phosphorylation of the phosphated konjac glucomannan is 0.35, and 35.0 parts of sodium tripolyphosphate and 25.0 parts of sodium trimetaphosphate are used in the phosphorylation reaction.

[0122] Comparative Example 7

[0123] The present comparative example is basically the same as Example 1, except that the mass concentration of the acetic acid aqueous solution in the preparation process of the chitosan / microcrystalline cellulose composite filler is 2.0%.

[0124] Comparative Example 8

[0125] The present comparative example is basically the same as Example 1, except that the concentration of the hydrochloric acid aqueous solution in the preparation process of the microcrystalline cellulose is 1.5 mol / L.

[0126] Comparative Example 9

[0127] The same as Example 1, except that the reaction temperature during the preparation of the phosphorylated konjac glucomannan was 40.0 °C.

[0128] Comparative Example 10

[0129] The same as Example 1, except that the temperature of step S1 during the preparation of the konjac gel food was 70 °C, and the temperature of step S2 was 70 °C.

[0130] Performance test:

[0131] Thermal stability test (test object: structural stability of konjac gel): To evaluate the structural stability of konjac gel during processing and storage, dynamic mechanical analysis (DMA) can be used to detect the storage modulus (E’) and loss factor (tan δ) of the gel at different temperatures, to analyze the thermal response behavior and structural retention ability of the gel. The test process is set to a temperature increase rate of 3 °C / min, a temperature range of 20-100 °C, and the elastic modulus change of the gel under temperature gradient change is recorded to reflect its thermal stability. This method refers to the ASTM D7028 standard.

[0132] Mechanical brittleness test (test object: brittleness and fracture performance of konjac gel): A texture analyzer is used to perform compression-penetration tests on gel samples to determine their fracture strength and brittleness index. A standard penetration probe (such as P / 2N) is used, with a compression speed of 1 mm / s, and the force value and fracture mode corresponding to the fracture point of the sample in the penetration force-displacement curve are recorded. This method can effectively reflect the fracture characteristics of the gel during the simulated chewing process in the oral cavity.

[0133] Moisture retention and water separation rate test (test object: storage stability of konjac gel): To evaluate the storage stability of konjac gel under normal temperature or refrigeration conditions, centrifugation and static weighing methods can be used to determine its water retention and water separation rate. Quantitative gel samples are placed in centrifuge tubes, and the centrifugation conditions are set to 5000 rpm for 10 min, and the supernatant is collected to calculate the water separation percentage. Combined with the mass change of the samples at different time points, the water retention capacity of the gel is evaluated.

[0134] Antibacterial performance test (test object: antibacterial activity of konjac gel): The antibacterial performance of konjac gel is evaluated using the inhibition zone method (agar diffusion method) and colony count method. Indicator bacteria such as E. coli and S. aureus are inoculated on the surface of agar medium and placed in gel samples containing chitosan. After 24 h of culture, the diameter of the inhibition zone is measured. At the same time, by comparing the reduction rate of colony-forming units (CFU) after inoculation with the control group, the antibacterial effect is further verified.

[0135] Sensory evaluation experiment (test object: gel food quality): organize more than 10 professional sensory groups, use 9-point scale (ISO 8586:2012) to evaluate the brittleness, elasticity and overall acceptance, and focus on the correlation between brittleness and gel strength.

[0136] The performance of konjac gel in examples 1-4 and comparative examples 1-10 is summarized in table 1, which is characterized by systematic morphology, phase analysis and performance test, and the rationality of the application is fully verified. Figures 1-2 Clearly shows the microstructure and crystal structure characteristics of microcrystalline cellulose, and verifies the high purity and good crystallinity of the raw material; Figures 3-4 Further confirms the successful compounding of chitosan and microcrystalline cellulose and its synergistic effect, and shows the uniform dispersibility and enhanced crystalline structure of the composite filler; Figures 5-6 Then intuitively presents the micro network structure and actual product quality of the final konjac gel food. Figures 7-9 The performance comparison data quantitatively verify the technical advantages of the application, including the synergistic improvement of storage modulus and breaking strength ( Figure 7 ), the ideal negative correlation between brittleness index and water separation rate ( Figure 8 ), and the positive correlation between storage modulus and antibacterial performance ( Figure 9) confirmed the innovative value of the product of the present application with excellent mechanical properties and antibacterial properties, and these correlation analysis results together showed that the konjac gel food prepared by the present application achieved significant improvement in structural stability, texture characteristics and functionality. As can be seen from Table 1, due to the use of ordinary konjac glucomannan instead of phosphated konjac glucomannan, the crosslinking density and stability of the gel network structure were significantly reduced, the thermal stability was decreased, the water retention capacity was weakened, and the lack of introduction of phosphate groups made the antibacterial performance obviously insufficient. The use of microcrystalline cellulose as a filler alone without the use of chitosan / microcrystalline cellulose composite filler lost the natural antibacterial activity of chitosan and the synergistic enhancement effect with konjac glucomannan, resulting in a sharp decline in antibacterial performance, and the mechanical strength and brittleness were also negatively affected. When the mass ratio of chitosan to microcrystalline cellulose was too low, the loading capacity of chitosan was insufficient, and the composite filler could not fully exert the enhancement and antibacterial effect, and the overall performance improvement was limited. When the particle size of the composite filler was too large, it was not uniformly dispersed in the gel matrix, which easily formed stress concentration points, reducing the mechanical properties and thermal stability of the gel. The presence of large particles also affected the sensory quality. When the mass ratio of phosphated konjac glucomannan to composite filler deviated from the optimal ratio, the synergistic effect between the components was weakened, and although the single performance was improved, the overall performance was still not ideal. Too high phosphating degree and too much phosphating agent may cause excessive crosslinking, making the gel brittle, and the residual phosphate may affect food safety and taste. The use of high concentration of acetic acid in the preparation process of the composite filler may cause partial degradation and gelation of the chitosan molecular chain, affecting its uniform loading on the surface of the microcrystalline cellulose. The use of too high concentration of hydrochloric acid in the preparation process of the microcrystalline cellulose may cause excessive hydrolysis and decrease of the crystallinity of the cellulose molecular chain, affecting its enhancement effect as a filler. Too low phosphating reaction temperature may not fully react, and the phosphating degree may not reach the ideal level, affecting the crosslinking density of the gel and the overall performance. Too high temperature in the gel preparation process may cause thermal degradation of the konjac glucomannan molecules and damage to the gel network structure, and high temperature may also affect the activity of chitosan, which may cause the performance of the gel to decline.

[0137] Table 1 Performance summary of konjac gel of examples 1-4 and comparative examples 1-10

[0138]

[0139] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that any equivalent structural transformation made within the concept of the present application, using the contents of the present application specification and drawings, should be covered within the protection scope of the claims of the present application.

Claims

1. A konjac gel food, characterized by, The raw materials include the following by weight: 50.0-100.0 parts of phosphorylated konjac glucomannan, 25.0-40.0 parts of chitosan / microcrystalline cellulose composite filler, 2.0-6.0 parts of calcium chloride, 1.0-4.0 parts of trisodium citrate, 1.0-5.0 parts of citric acid, 1.0-3.0 parts of sodium trimetaphosphate, 2.0-8.0 parts of carrageenan, 2.0-6.0 parts of sodium alginate, 1.0-3.0 parts of calcium lactate, and 200.0-400.0 parts of deionized water; The mass ratio of microcrystalline cellulose to chitosan in the chitosan / microcrystalline cellulose composite filler is (1.0-5.0):(0.5-2.0); The average particle length of the chitosan / microcrystalline cellulose composite filler is 16-50 μm, and the average diameter is 2.0-5.0 μm; The preparation method of the phosphorylated konjac glucomannan is as follows: 100.0 parts of konjac glucomannan is dispersed in 500.0-800.0 parts of deionized water, and a uniform colloid solution is prepared by mechanical stirring at a stirring rate of 300.0-500.0 rpm in an air atmosphere at normal pressure, while heating to a reaction temperature of 50.0-70.0°C at a heating rate of 3.0-5.0°C / min for 1.0-2.0 h, then 15.0-25.0 parts of sodium tripolyphosphate and 8.0-15.0 parts of sodium trimetaphosphate are added in sequence, the pH value of the system is adjusted to 6.8-7.2 with 0.1 mol / L sodium hydroxide aqueous solution, then the reaction system is heated to 90.0-95.0°C at a heating rate of 5.0-8.0°C / min, and the stirring rate is 200.0-400.0 rpm at this temperature for 3.0-5.0 h, the pH value is monitored in real time and maintained stable during the reaction, after the reaction, the system is cooled to room temperature 25.0±2.0°C, then 85%-95% ethanol aqueous solution is added for alcohol precipitation separation, the precipitate is filtered through a microporous filter membrane with a pore size of 0.45-0.65 μm, washed with deionized water for 3-5 times until the filtrate is neutral, finally the product is dried in a vacuum drying oven at 45.0-60.0°C for 8.0-12.0 h, crushed by a pulverizer and sieved through a standard sieve of 120-200 mesh to obtain the phosphorylated konjac glucomannan product; The phosphorylation degree of the phosphorylated konjac glucomannan is 0.04-0.

20. The preparation method of the chitosan / microcrystalline cellulose composite filler is as follows: 20.0-50.0 parts of chitosan is added into 500.0-1000.0 parts of 0.5%-1.0% acetic acid aqueous solution, and the chitosan is completely dissolved by mechanical stirring at a stirring rate of 300.0-500.0 rpm at room temperature 25.0±2.0°C for 0.5-2.0 hours to obtain a chitosan solution with a pH value of 3.8-4.2; then 100.0 parts of microcrystalline cellulose is added into deionized water, and a microcrystalline cellulose suspension is prepared by using a high-speed shearing dispersion machine at a rotating speed of 8000.0-12000.0 rpm for 15.0-30.0 minutes; then the pH value of the suspension is adjusted to 5.5-6.0 by using 0.1 mol / L sodium hydroxide aqueous solution, and the chitosan solution is slowly added into the microcrystalline cellulose suspension at a dropping speed of 1.0-3.0 mL / min under continuous mechanical stirring; the pH value of the system is monitored in real time and maintained in the range of 5.8-6.2 during the dropping process; after the dropping is completed, the chitosan is uniformly loaded by using a high-speed shearing dispersion treatment at a rotating speed of 6000.0-8000.0 rpm for 1.0-2.0 hours; then the mixture is centrifuged at a centrifugal rate of 3000.0-5000.0 rpm for 10.0-15.0 minutes, and the supernatant is discarded; the precipitate is washed repeatedly for 2-3 times with deionized water until the filtrate is neutral; finally, the precipitate is dried in a vacuum freeze dryer at-50.0--40.0°C for 12.0-24.0 hours, and the target product is obtained after being crushed by a pulverizer and sieved through a standard sieve with a mesh size of 100-200; The preparation method of the microcrystalline cellulose is as follows: 100.0 parts of cellulose raw material is uniformly mixed with 800.0-1200.0 parts of 2.5-4.0 mol / L hydrochloric acid aqueous solution in a reactor with a condenser, and the mixture is subjected to mechanical stirring at a stirring rate of 200.0-400.0 rpm in an air atmosphere at normal pressure, while being heated to a reaction temperature of 100.0-105.0°C at a heating rate of 5.0-10.0°C / min for reflux hydrolysis reaction for 2.0-4.0 hours; after the reaction is completed, the system is cooled to room temperature 25.0±2.0°C at a cooling rate of 3.0-5.0°C / min, and then the solid product is separated by filtration through a microporous filter membrane with a pore size of 0.45-0.65 μm; the solid product is washed repeatedly with deionized water for 5-8 times until the pH value of the filtrate is 6.5-7.5; then the washed solid material is dried in a vacuum drying oven at 60.0-80.0°C for 4.0-8.0 hours; finally, the microcrystalline cellulose is obtained by treating the solid material with a high-speed shearing pulverizer at a rotating speed of 10000.0-15000.0 rpm for 30.0-60.0 minutes; The preparation method of the konjac gel food is characterized by comprising the following steps: S1: precisely weigh each weight part of raw materials, add the phosphated konjac glucmannan to deionized water, mechanically stir at 75-85℃ for 1-2 hours to prepare a uniform transparent colloidal solution; S2: adjust the temperature of the colloidal solution to 60-65℃, add the chitosan / microcrystalline cellulose composite filler, and use high-speed shearing dispersion technology to treat for 10-30 minutes at a speed of 4000-6000 rpm to ensure uniform dispersion of the filler, then sequentially add carrageenan and sodium alginate, and continue to stir at high speed for 10-20 minutes until completely dissolved; S3: adjust the temperature of the system to 50-55℃, sequentially add calcium chloride, calcium lactate, citric acid, trisodium citrate, and sodium trimetaphosphate, stir for 5-10 minutes after adding each component, adjust the final pH value to 6.5-7.0 with citric acid, prepare a konjac gel precursor, then place the precursor in a vacuum environment for 10-20 minutes to remove bubbles in the system, with a vacuum degree of -0.08 to -0.10 MPa; S4: pour the defoamed precursor into a pre-made mold, stand at room temperature for 25-35 minutes for preliminary gelation, then place the initial gel product in a 2-6℃ refrigerated environment for 2-4 hours for solidification, demold and cut into the desired size as needed to prepare the konjac gel food.

2. The konjac gel food of claim 1, characterized in that, the weight ratio of carrageenan to sodium alginate is (1-3):(1-2); the weight ratio of calcium chloride to calcium lactate is (1-3):(0.5-1.5).

3. The konjac gel food according to claim 1, wherein In the preparation process, temperature gradient control is used to realize the ordered construction of layered gel network, where the high temperature of 75-85℃ in step S1 promotes the full swelling of phosphated konjac glucmannan, the medium temperature of 60-65℃ in step S2 ensures the uniform dispersion of the composite filler and the dissolution of polysaccharide components, the low temperature of 50-55℃ in step S3 avoids the thermal inactivation of the crosslinking agent, and the temperature gradient from room temperature to refrigeration temperature in step S4 realizes the gradual solidification and stabilization of the gel network.

4. Use of the konjac gel food according to any one of claims 1 to 3, characterized in that, Application in simulated animal cartilage tissue texture food.

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