A method for improving the viscosity of konjac glucomannan, a konjac glucomannan and dihydromyricetin composite hydrogel, and its application

Abstract

The present invention provides a method for increasing the viscosity of konjac glucomannan, as well as a composite hydrogel of konjac glucomannan and dihydromyricetin and its application. Specifically, the method for increasing the viscosity of konjac glucomannan is to first mix dihydromyricetin and water to prepare an aqueous solution of dihydromyricetin, and then add konjac glucomannan to the aqueous solution of dihydromyricetin and mix to obtain a composite hydrogel. The present invention unexpectedly discovers that the viscosity of konjac glucomannan can be increased by dihydromyricetin, and the degree of decrease in the viscosity of konjac glucomannan during digestion can be reduced, and its residence time in the gastrointestinal tract can be increased. While dihydromyricetin increases the viscosity of konjac glucomannan, the formed complex increases the stability of dihydromyricetin. The discovery of the present invention makes the composition promising for application in the field of meal replacements.

Description

Technical Field

[0001] The present invention relates to a method for increasing the viscosity of konjac glucomannan, and a composite hydrogel of konjac glucomannan and dihydromyricetin and its application. Background Art

[0002] Dietary fiber and polyphenols, as functional components with important functions for human health, often produce adverse effects when used together, such as a decrease in viscosity and a decrease in water-binding ability. The viscosity and water-holding capacity of dietary fiber are beneficial to the excretion of metabolic wastes and the treatment of constipation. Therefore, it is very necessary to overcome the decrease in its viscosity.

[0003] As the most viscous dietary fiber known, konjac glucomannan is often used in meal replacement foods to produce a sense of fullness. Konjac glucomannan is a high-molecular-weight non-ionic polysaccharide, and its most typical characteristic is instability, and the viscosity will increase first and then decrease with the storage time. In order to overcome the decrease in viscosity, CN 201610585686.4 discloses a method for improving the stability of konjac glucomannan. By adding strong oxidants (hydrogen peroxide, sodium hypochlorite or potassium permanganate) to konjac powder to inactivate the glucomannanase activity in konjac powder to reduce the decrease in viscosity. CN 202010209078.X also discloses a method for improving the stability of konjac glucomannan, and zinc salts are added during the preparation of konjac gum to improve its initial viscosity and long-term stability.

[0004] Disadvantages of CN 201610585686.4: The operation steps are cumbersome (in order to remove sulfur dioxide in konjac powder, first, it is necessary to measure the content of sulfur dioxide in konjac powder, so as to calculate the dosage of strong oxidant. Mix konjac powder with alcohol and stir well for 20 minutes, then centrifuge the material to remove the liquid phase part and residual hydrogen peroxide, and finally heat and dry konjac powder.), and the residue of strong oxidants such as hydrogen peroxide poses a certain food safety risk. Summary of the Invention

[0005] The present invention solves the problems in the prior art, and can increase the viscosity of konjac glucomannan and improve the thermal stability of dihydromyricetin at the same time.

[0006] One aspect of the present invention provides a method for increasing the viscosity of konjac glucomannan, and the method comprises the following steps:

[0007] Mix konjac glucomannan, dihydromyricetin and water to prepare a composite hydrogel.

[0008] Further, the preparation method is to first mix dihydromyricetin and water to prepare an aqueous solution of dihydromyricetin, and then add konjac glucomannan to the aqueous solution of dihydromyricetin and mix to obtain a composite hydrogel.

[0009] Further, the mass ratio of konjac glucomannan to dihydromyricetin is 100:1 - 20, preferably 100:2 - 10, such as 100:4, 100:6, 100:8.

[0010] Further, the concentration of konjac glucomannan in the composite hydrogel is 0.1 - 2 g of konjac glucomannan per 100 mL of water. Preferably, it is 0.5 - 1.5 g of konjac glucomannan per 100 mL of water. More preferably, it is 0.8 - 1.2 g of konjac glucomannan per 100 mL of water. For example, it contains 0.8 g, 0.9 g, 1.0 g, 1.1 g, 1.2 g of konjac glucomannan per 100 mL of water.

[0011] Further, the concentration of dihydromyricetin in the composite hydrogel is 0.01 - 0.2 g of dihydromyricetin per 100 mL of water. Preferably, it is 0.02 - 0.15 g of dihydromyricetin per 100 mL of water. More preferably, it is 0.02 - 0.1 g of dihydromyricetin per 100 mL of water. For example, it contains 0.04 g, 0.06 g, 0.08 g, 0.1 g of dihydromyricetin per 100 mL of water.

[0012] Another aspect of the present invention provides a composition of dihydromyricetin and konjac glucomannan, and the composition is composed of dihydromyricetin and konjac glucomannan.

[0013] Further, the mass ratio of konjac glucomannan to dihydromyricetin is 100:1 - 20, preferably 100:2 - 10, such as 100:4, 100:6, 100:8.

[0014] Another aspect of the present invention is a composite gel of dihydromyricetin and konjac glucomannan, which is prepared by mixing konjac glucomannan, dihydromyricetin and water to prepare the composite gel.

[0015] Further, the preparation method is to first mix dihydromyricetin and water to prepare an aqueous solution of dihydromyricetin, and then add konjac glucomannan to the aqueous solution of dihydromyricetin and mix to obtain the composite hydrogel.

[0016] Further, the mass ratio of konjac glucomannan to dihydromyricetin is 100:1 - 20, preferably 100:2 - 10, such as 100:4, 100:6, 100:8.

[0017] Further, the concentration of konjac glucomannan in the composite hydrogel is 0.1 - 2 g of konjac glucomannan per 100 mL of water. Preferably, it is 0.5 - 1.5 g of konjac glucomannan per 100 mL of water. More preferably, it is 0.8 - 1.2 g of konjac glucomannan per 100 mL of water. For example, it contains 0.8 g, 0.9 g, 1.0 g, 1.1 g, 1.2 g of konjac glucomannan per 100 mL of water.

[0018] Further, the concentration of dihydromyricetin in the composite hydrogel is 0.01 - 0.2 g of dihydromyricetin per 100 mL of water. Preferably, it is 0.02 - 0.15 g of dihydromyricetin per 100 mL of water. More preferably, it is 0.02 - 0.1 g of dihydromyricetin per 100 mL of water. For example, it contains 0.04 g, 0.06 g, 0.08 g, 0.1 g of dihydromyricetin per 100 mL of water.

[0019] Another aspect of the present invention provides a method for preparing the above composite gel.

[0020] Further, the preparation method is to first mix dihydromyricetin and water to prepare an aqueous solution of dihydromyricetin, and then add konjac glucomannan to the aqueous solution of dihydromyricetin and mix to obtain the composite hydrogel.

[0021] Another aspect of the present invention provides the use of the above composition or composite gel in the preparation of a meal replacement.

[0022] Another aspect of the present invention provides a meal replacement, which comprises the above composite gel or the above composition.

[0023] Further, the meal replacement further includes any one or a combination of flavoring agents, vitamins, trace elements, and proteins.

[0024] Another aspect of the present invention provides the use of the above composition or composite gel in the preparation of a meal replacement composition for reducing gastric digestion efficiency and increasing gastric digestion time.

[0025] Another aspect of the present invention provides a method for improving the thermal stability of dihydromyricetin, which includes mixing konjac glucomannan, dihydromyricetin, and water to prepare a composite hydrogel.

[0026] Further, the preparation method is to first mix dihydromyricetin and water to prepare an aqueous solution of dihydromyricetin, and then add konjac glucomannan to the aqueous solution of dihydromyricetin and mix to obtain the composite hydrogel.

[0027] Further, the mass ratio of konjac glucomannan to dihydromyricetin is 100:1 - 20, preferably 100:2 - 10, for example 100:4, 100:6, 100:8.

[0028] Furthermore, the concentration of konjac glucomannan in the composite hydrogel is 0.1 - 2 g of konjac glucomannan per 100 mL of water. Preferably, it is 0.5 - 1.5 g of konjac glucomannan per 100 mL of water. More preferably, it is 0.8 - 1.2 g of konjac glucomannan per 100 mL of water. For example, it contains 0.8 g, 0.9 g, 1.0 g, 1.1 g, 1.2 g of konjac glucomannan per 100 mL of water.

[0029] Furthermore, the concentration of dihydromyricetin in the composite hydrogel is 0.01 - 0.2 g of dihydromyricetin per 100 mL of water. Preferably, it is 0.02 - 0.15 g of dihydromyricetin per 100 mL of water. More preferably, it is 0.02 - 0.1 g of dihydromyricetin per 100 mL of water. For example, it contains 0.04 g, 0.06 g, 0.08 g, 0.1 g of dihydromyricetin per 100 mL of water.

[0030] Beneficial effects

[0031] 1. The present invention unexpectedly discovers that dihydromyricetin can increase the viscosity of konjac glucomannan, and can reduce the degree of viscosity decrease of konjac glucomannan during digestion, increasing its retention time in the gastrointestinal tract.

[0032] 2. While dihydromyricetin increases the viscosity of konjac glucomannan, the formed complex increases the stability of dihydromyricetin.

[0033] 3. Dihydromyricetin and konjac glucomannan produce a synergistic and unexpected interaction effect. After the compounding of konjac glucomannan and dihydromyricetin, it can not only increase the viscosity, but also improve the thermal stability of dihydromyricetin. Moreover, the preparation method is simple, which can be achieved by simple stirring. The raw materials are simple and no special equipment is required, suitable for consumers to operate by themselves and the preparation is very rapid.

[0034] 4. Both dihydromyricetin and konjac glucomannan are functional food ingredients, which not only have no safety hazards to the human body, but also can enrich the nutritional value of both. Description of the drawings

[0035] Figure 1 It is the viscosity detection result of gels prepared from different concentrations of dihydromyricetin and konjac glucomannan in Example 1.

[0036] Figure 2 It is the apparent viscosity result after digestion of the dihydromyricetin and konjac glucomannan composite gel in Example 2.

[0037] Figure 3For the prototypical retention amount of dihydromyricetin in the composite gel of dihydromyricetin and konjac glucomannan under different heating temperature conditions in Example 3, where A is the result under the condition of 60 °C and B is the result under the condition of 100 °C. Detailed implementation manners

[0038] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following provides a detailed description of the specific implementation manners of the present invention, but it should not be construed as a limitation on the implementable scope of the present invention.

[0039] Example 1 Preparation of the composite gel of dihydromyricetin and konjac glucomannan

[0040] Take 0.1 g of dihydromyricetin and add it to 100 mL of distilled water. Stir magnetically at 60 °C for 30 min to fully dissolve it, and then cool it to room temperature to obtain an aqueous solution of dihydromyricetin with a mass concentration of 0.10%. Put a DC-type stirring paddle into a beaker and stir at 250 r / min. Weigh 1 g of konjac glucomannan (KGM, source: Hubei Qiangsen Konjac Technology Co., Ltd., KJ30, purity > 90%, molecular weight 200 - 2000 kDa) with an analytical balance, and slowly add it to the beaker containing the aqueous solution of dihydromyricetin. After stirring for 2 h, a composite gel of dihydromyricetin and konjac glucomannan is obtained.

[0041] Using the same method, prepare aqueous solutions of dihydromyricetin with mass concentrations of 0.06% and 0.08%, and prepare corresponding composite gels of dihydromyricetin and konjac glucomannan.

[0042] After compounding konjac glucomannan and dihydromyricetin, perform a steady-state scan on the sample with a DHR-2 rheometer. The viscosity experiment results of Example 1 are shown in Figure 1 . Among them, CR represents the group of pure 1% KGM without adding dihydromyricetin. It can be seen that adding dihydromyricetin can increase the viscosity of konjac glucomannan, and as the addition amount of dihydromyricetin increases, the viscosity continuously increases.

[0043] Example 2 Apparent viscosity experiment of the composite gel of dihydromyricetin and konjac glucomannan after digestion

[0044] In order to study the rheological properties of the sample in the digested state, first mix the sample with the saliva simulation solution at a volume ratio of 10:1 and stir for 1 - 2 min to simulate chewing in the oral cavity. Then mix the sample with the simulated gastric juice at a ratio of 1:1 and digest it in a constant temperature oscillator at 37 °C and 250 r / min to simulate the gastric digestion state. Finally, take samples at the time points of 0 min, 15 min, 30 min, 60 min, and 120 min during gastric digestion. In order to simulate the rheological properties of the sample in the stomach, at a shear rate of 50 s -1Measure the apparent viscosity of the digesta below. Among them, the sample was prepared in the same way as in Example 1. In the gastric digestion stage, 1% KGM was fixed, different amounts of dihydromyricetin were added and compounded with KGM, and then digested. 0.00% DMY means no dihydromyricetin, that is, konjac glucomannan at 0.01 g / ml.

[0045] The experimental results are shown in Figure 2 , through the comparison before digestion, it can be seen that with the addition of dihydromyricetin, the viscosity of the composite gel increases. In the gastric digestion stage, although the apparent viscosity of each experimental group shows a different degree of decrease in apparent concentration over time. However, at the same time, with the increase in the addition amount of dihydromyricetin, it can be found in the comparison among groups that the addition amount of dihydromyricetin is positively correlated with the viscosity of the system. When the addition amount of dihydromyricetin is above 0.06%, the viscosity of the digesta is significantly greater than that of the control group (P < 0.05) (the control group is the gel containing only konjac glucomannan without dihydromyricetin), indicating that the addition of dihydromyricetin can increase the apparent viscosity of the sample. From Figure 2 it can be seen that the viscosities of both the experimental group and the control group continuously decrease with the progress of digestion time. And the decrease amplitude of the viscosity is also related to the addition of dihydromyricetin. With the increase in the addition amount of dihydromyricetin, the decrease amplitude of the viscosity during digestion is smaller. Among them, the viscosity of the control group decreased by 5.2%, and the experimental group only decreased by 0.7%, indicating that dihydromyricetin can improve the stability during digestion, especially the digestive stability in the stomach. And this increase in stability is beneficial to the residence time of the complex in the stomach and increases satiety.

[0046] Example 3 Thermal stability of dihydromyricetin

[0047] Take a certain amount of dihydromyricetin and dissolve it in ultrapure water, stir it in a water bath at 60 °C for 30 min to prepare a 0.001% DMY solution. Cool it to room temperature, filter it through a 0.22 μm microporous filter membrane, and divide the filtered solution into 4 parts, 2 parts are 0.001% DMY, and 2 parts are added with a little KGM powder and magnetically stirred at room temperature for 2 h to make a solution containing 0.01% KGM and 0.001% DMY. 2. Sample treatment method:

[0048] Then heat the samples in a water bath at 60 °C and 100 °C respectively, take samples at regular intervals, and measure the absorbance value to calculate the prototype retention amount. To avoid water evaporation, cover a layer of tin foil on the test tube containing the sample.

[0049] The experimental results are shown in Figure 3And as shown in Table 1, when heated at 60°C for 2 hours, 5% of dihydromyricetin decomposed; when heated for 6 hours, 10% decomposed, while when KGM was added and heated for 6 hours, only 5% decomposed. When heated at 100°C for only 10 minutes, 10% of dihydromyricetin decomposed, while when KGM was added, only 2% decomposed, increasing the prototype retention by 8%. In summary, KGM is beneficial to improving the thermal stability of dihydromyricetin, and as the heating time progresses, this protective effect becomes stronger.

[0050] Table 1 Prototype retention data of dihydromyricetin after heating at 60°C

[0051]

[0052] a and b represent significant differences. The same letters indicate no difference between groups, and different letters indicate significant differences in results. This result shows that the addition of KGM significantly improves the thermal stability of dihydromyricetin.

[0053] Table 2 Prototype retention data of dihydromyricetin after heating at 100°C

[0054]

[0055]

[0056] a and b represent significant differences. The same letters indicate no difference between groups, and different letters indicate significant differences in results. This result shows that the addition of KGM significantly improves the thermal stability of dihydromyricetin.

Claims

1. A method for increasing the viscosity of konjac glucomannan, characterized in that, The method comprises the following steps: Konjac glucomannan, dihydromyricetin and water are mixed to prepare a composite hydrogel.

2. The method according to claim 1, characterized in that, In the method, dihydromyricetin and water are first mixed to prepare an aqueous solution of dihydromyricetin, and then konjac glucomannan is added to the aqueous solution of dihydromyricetin and mixed to obtain a composite hydrogel.

3. The method according to claim 1, characterized in that, The mass ratio of konjac glucomannan to dihydromyricetin is 100:1 - 20.

4. The method according to claim 3, characterized in that, The mass ratio of konjac glucomannan to dihydromyricetin is 100:2 - 10.

5. The method according to claim 1, characterized in that, In the composite hydrogel, the concentration of konjac glucomannan is 0.1 - 2 g of konjac glucomannan per 100 mL of water, and the concentration of dihydromyricetin in the composite hydrogel is 0.01 - 0.2 g of dihydromyricetin per 100 mL of water.

6. The method according to claim 5, characterized in that, There is 0.5 - 1.5 g of konjac glucomannan per 100 mL of water, and 0.02 - 0.15 g of dihydromyricetin per 100 mL of water.

7. The method according to claim 6, wherein There is 0.8 - 1.2 g of konjac glucomannan per 100 mL of water; there is 0.02 - 0.1 g of dihydromyricetin per 100 mL of water.

8. Composite gel of dihydromyricetin and konjac glucomannan, characterized in that, It prepares a composite gel by mixing konjac glucomannan, dihydromyricetin and water; The preparation method is to first mix dihydromyricetin and water to prepare an aqueous solution of dihydromyricetin, and then add konjac glucomannan to the aqueous solution of dihydromyricetin and mix to obtain a composite hydrogel; The mass ratio of konjac glucomannan to dihydromyricetin is 100:1 - 20; In the composite hydrogel, the concentration of konjac glucomannan is 0.1 - 2 g of konjac glucomannan per 100 mL of water; the concentration of dihydromyricetin in the composite hydrogel is 0.01 - 0.2 g of dihydromyricetin per 100 mL of water.

9. The composite gel according to claim 8, wherein, There is 0.5 - 1.5 g of konjac glucomannan per 100 mL of water.

10. The composite gel according to claim 8, characterized in that, There is 0.02 - 0.15 g of dihydromyricetin per 100 mL of water.

11. The preparation method of the composite gel according to any one of claims 8-10; characterized in that, The preparation method is to first mix dihydromyricetin and water to prepare an aqueous solution of dihydromyricetin, and then add konjac glucomannan to the aqueous solution of dihydromyricetin and mix to obtain a composite hydrogel.

12. Use of the composite gel according to any one of claims 8 - 10 in the preparation of an energy - enhanced meal replacement or functional food.

13. A meal replacement, characterized in that, The meal replacement contains the composite gel according to any one of claims 8 - 10.

14. The meal replacement according to claim 13, characterized in that, The meal replacement further includes any one or a combination of flavoring agents, vitamins, trace elements, proteins.

15. Use of the composite gel according to any one of claims 8 - 10 in the preparation of a meal replacement composition for reducing gastric digestion efficiency and increasing gastric digestion time.

16. A method for improving the thermal stability of dihydromyricetin, characterized in that, The method includes mixing konjac glucomannan, dihydromyricetin and water to prepare a composite hydrogel.

17. The method according to claim 16, wherein The preparation method is to first mix dihydromyricetin and water to prepare an aqueous solution of dihydromyricetin, and then add konjac glucomannan to the aqueous solution of dihydromyricetin and mix to obtain a composite hydrogel.

18. The method according to claim 16, characterized in that, The mass ratio of konjac glucomannan to dihydromyricetin is 100:1 - 20.

19. The method according to claim 16, wherein In the composite hydrogel, the concentration of konjac glucomannan is 0.1 - 2 g of konjac glucomannan per 100 mL of water.

20. The method according to claim 16, characterized in that, In the composite hydrogel, the concentration of dihydromyricetin is 0.01 - 0.2 g of dihydromyricetin per 100 mL of water.

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