A modified allulose and preparation method thereof

Abstract

The present invention discloses a modified psicose and a preparation method thereof, which belongs to the technical field of organic synthesis, and specifically comprises the following steps: (1) adding sodium chloride to a psicose solution and mixing evenly, and then adding vinyl acetate to react for 2-4 hours under a pH value of 9-10; (2) terminating the reaction of step (1) after completion, and sequentially concentrating, crystallizing and drying to obtain the modified psicose. The present invention adopts a wet modification technology to esterify the hydroxyl group of psicose, thereby blocking the Maillard reaction and making it difficult to produce the Maillard reaction; and the viscosity of psicose can be increased by the esterification reaction, and the properties of psicose can be improved. After reaching the human body, it can be restored to the psicose body, which does not affect the action and effect of psicose itself and increases the scope of application of psicose.

Description

Technical Field

[0001] The invention belongs to the technical field of organic compound synthesis, and in particular relates to modified psicose and a preparation method thereof. Background Art

[0002] Compared with other low-calorie sweeteners, the biggest advantage of allulose is that its properties and functions are extremely similar to those of sucrose. It is safe enough and similar enough to "sugar", enabling it to achieve excellent sugar replacement effects in applications where other sweeteners are difficult to perform.

[0003] The sweetness of allulose is about 70% of that of sucrose, but its calories are much lower than sucrose, only one-tenth of sucrose, with the calories of allulose being 0.4 kal / g.

[0004] Commercially available allulose is usually in the form of crystalline powder. Allulose is mainly sold as a sweetener raw material in the form of monomers or compound sugars and can be used in the development of sugar-free beverages, candies, baking and dairy products. However, due to its low viscosity and easy browning, allulose cannot be used well in high-heat cooking such as baking or frying foods, because it will quickly caramelize at high temperatures, resulting in undesirable taste and texture of foods containing allulose, limiting its use in certain foods.

[0005] Therefore, being able to provide a modified psicose to increase the scope of application of psicose is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0006] In view of this, the present invention provides a modified allulose and a preparation method thereof. The preparation method of the present invention has mild reaction conditions, is easy to control the production process, has stable product quality and is low in cost.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A method for preparing modified psicose, comprising the following steps:

[0009] (1) After adding sodium chloride to the allulose solution and mixing evenly, vinyl acetate was added and reacted at a pH of 9-10 for 2-4 hours;

[0010] (2) After the reaction in step (1) is completed, the modified psicose is obtained by concentration, crystallization and drying.

[0011] Preferably, the addition ratio of sodium chloride in step (1) is 1-2.5% of the mass of the psicose.

[0012] The invention makes the reaction more uniform and effective and easy to control by adding sodium chloride.

[0013] Preferably, in step (1), the molar ratio of the psicose to the vinyl acetate is 1.5-2:1.

[0014] Preferably, the concentration of the psicose solution in step (1) is 40-60 wt %.

[0015] Preferably, the pH value in step (1) is adjusted using sodium carbonate.

[0016] Preferably, the reaction temperature in step (1) is 25-30° C., and the stirring rate is 250-350 rpm.

[0017] Preferably, the termination in step (2) can be achieved by adjusting the pH value to 5.0-5.5.

[0018] Preferably, the pH value is adjusted using hydrochloric acid.

[0019] Preferably, the concentration is performed until no water is evaporated, and the crystallization is performed using isopropanol anti-solvent crystallization.

[0020] The modified psicose is obtained according to the preparation method described above.

[0021] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The present invention adopts a wet modification technology to esterify the hydroxyl group of psicose, thereby blocking the Maillard reaction and making it difficult to produce the Maillard reaction. The esterification reaction can increase the viscosity of psicose and improve the properties of psicose. After reaching the human body, the psicose can be restored to its original state, which does not affect the function and effect of psicose itself and increases the application scope of psicose. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0024] Figure 1 This is a liquid chromatogram of psicose before modification in Example 1 of the present invention;

[0025] Figure 2 This is the liquid chromatogram of modified allulose in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] The present invention provides a method for preparing modified psicose, and the specific steps are as follows:

[0029] (1) Prepare a 40 wt% solution of allulose with deionized water, and adjust the pH to 9.0 by adding 10% sodium carbonate; then add 1.5% sodium chloride (based on the mass of allulose) to the allulose solution and stir at 250 rpm for 3 min. While maintaining the stirring state, add vinyl acetate (1.5 times the molar mass of allulose) dropwise, and react at 25°C for 2 h, maintaining the pH at 9.0;

[0030] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.0 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60°C to obtain modified psicose. Figure 1 and 2 The liquid chromatograms before and after the modification of the psicose of the present invention are shown. According to the relevant spectra, it can be seen that the modification of the psicose of the present invention is successful.

[0031] Example 2

[0032] The present invention provides a method for preparing modified psicose, and the specific steps are as follows:

[0033] (1) Prepare a 50 wt% solution of allulose with deionized water, and adjust the pH to 9.8 by adding 10% sodium carbonate; then add 1.5% sodium chloride (based on the mass of allulose) to the allulose solution and stir at 300 rpm for 3 min. While maintaining the stirring state, add vinyl acetate (1.8 times the molar mass of allulose) dropwise, and react at 25°C for 2 h, maintaining the pH at 9.0;

[0034] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.0 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60° C. to obtain modified psicose.

[0035] Example 3

[0036] The present invention provides a method for preparing modified psicose, and the specific steps are as follows:

[0037] (1) Prepare a 60 wt% solution of allulose with deionized water, and adjust the pH to 9.5 by adding 10% sodium carbonate; then add 1.5% sodium chloride (based on the mass of allulose) to the allulose solution and stir at 350 rpm for 3 min. While maintaining the stirring state, add vinyl acetate (2 times the molar mass of allulose) dropwise, and react at 30°C for 4 h, maintaining the pH at 9.5;

[0038] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.5 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60° C. to obtain modified psicose.

[0039] Example 4

[0040] The present invention provides a method for preparing modified psicose, and the specific steps are as follows:

[0041] (1) Prepare a 40 wt% solution of allulose with deionized water, and adjust the pH to 9.0 by adding 10% sodium carbonate; then add 1% sodium chloride (based on the mass of allulose) to the allulose solution and stir at 250 rpm for 3 min. While maintaining the stirring state, add vinyl acetate (1.5 times the molar mass of allulose) dropwise, and react at 25°C for 2 h, maintaining the pH at 9.0;

[0042] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.0 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60° C. to obtain modified psicose.

[0043] Example 5

[0044] The present invention provides a method for preparing modified psicose, and the specific steps are as follows:

[0045] (1) Prepare a 40 wt% solution of allulose with deionized water, and adjust the pH to 9.0 by adding 10% sodium carbonate; then add 2.5% sodium chloride (based on the mass of allulose) to the allulose solution and stir at 250 rpm for 3 min. While maintaining the stirring state, add vinyl acetate (1.5 times the molar mass of allulose) dropwise, and react at 25°C for 2 h, maintaining the pH at 9.0;

[0046] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.0 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60° C. to obtain modified psicose.

[0047] Comparative Example 1

[0048] Provided is a method for preparing modified allulose, the specific steps of which are as follows:

[0049] (1) Prepare a 40 wt% solution of allulose with deionized water, and adjust the pH to 7.0 by adding 10% sodium carbonate; then add 1.5% sodium chloride (based on the mass of allulose) to the allulose solution and stir at 250 rpm for 3 min. While maintaining the stirring state, add vinyl acetate (2 times the molar mass of allulose) dropwise, and react at 25°C for 2 h, maintaining the pH at 5.0;

[0050] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.0 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60° C. to obtain modified psicose.

[0051] Comparative Example 2

[0052] Provided is a method for preparing modified allulose, the specific steps of which are as follows:

[0053] (1) Prepare a 40 wt% solution of allulose with deionized water, and adjust the pH to 11.0 by adding 10% sodium carbonate; then add 1.5% sodium chloride (based on the mass of allulose) to the allulose solution and stir at 250 rpm for 3 min. While maintaining the stirring state, add vinyl acetate (2 times the molar mass of allulose) dropwise, and react at 25°C for 2 h, maintaining the pH at 5.0;

[0054] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.0 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60° C. to obtain modified psicose.

[0055] Comparative Example 3

[0056] Provided is a method for preparing modified allulose, the specific steps of which are as follows:

[0057] (1) Prepare a 40 wt% solution of allulose with deionized water, and adjust the pH to 9.0 by adding 10% sodium carbonate; then add 1.5% sodium chloride (based on the mass of allulose) to the allulose solution and stir at 250 rpm for 3 min. While maintaining the stirring state, add sodium tripolyphosphate (1.5 times the molar mass of allulose) dropwise, and react at 25°C for 2 h, maintaining the pH at 9.0;

[0058] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.0 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60° C. to obtain modified psicose.

[0059] Comparative Example 4

[0060] Provided is a method for preparing modified allulose, the specific steps of which are as follows:

[0061] (1) Prepare a 40 wt% solution of allulose with deionized water, and adjust the pH to 9.0 by adding 10% sodium carbonate; then, add vinyl acetate (1.5 times the molar mass of allulose) dropwise to the allulose solution under stirring at 250 rpm, and react at 25°C for 2 h, maintaining the pH at 9.0;

[0062] (2) After the reaction in step (1) is completed, the pH value is adjusted to 5.0 with 3% hydrochloric acid to terminate the reaction, and the mixture is concentrated by rotary evaporation until no water is evaporated. After crystallization with excess isopropanol anti-solvent, the mixture is dried at 60° C. to obtain modified psicose.

[0063] Effect Experiment

[0064] Since alkaline amino acids are prone to Maillard reaction, histidine was selected to carry out Maillard reaction with the modified psicose of each embodiment and comparative example, and commercially available (food grade, purity greater than 98%) psicose and sucrose were used as controls. The absorbance at 420 nm within 180 min was measured under the conditions of temperature 90° C., pH 8, and sugar-ammonia ratio 3:1. The absorbance results of each embodiment and comparative example are shown in Table 1.

[0065] Table 1 Absorbance results of modified psicose prepared in various examples and comparative examples

[0066]

[0067] As can be seen from the above table, the absorbance of Examples 1-3 is similar to that of sucrose, and sucrose does not undergo the Maillard reaction. This is mainly because sucrose is a non-reducing sugar and does not contain free carbonyl groups. Therefore, under the experimental conditions, it does not show reaction activity with amino acids. As the amount of vinyl acetate increases, the absorbance shows a downward trend. The lower the absorbance, the more vinyl acetate reacts with the free carbonyl groups of psicose to undergo an esterification reaction, which results in fewer free carbonyl groups in psicose and makes it less likely to undergo the Maillard reaction. At the same time, compared with vinyl acetate, the esterification reaction is less likely to occur when the esterifying agent is replaced. The reaction control effect is poor when sodium chloride is not added during the reaction process.

[0068] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing modified psicose, characterized in that: The specific steps include: (1) After adding sodium chloride to the allulose solution and mixing evenly, vinyl acetate was added and reacted at a pH of 9-10 for 2-4 hours; (2) terminating the reaction in step (1) after completion, and sequentially concentrating, crystallizing and drying to obtain modified psicose; The addition ratio of sodium chloride in step (1) is 1-2.5% of the mass of allulose; The molar ratio of vinyl acetate to psicose in step (1) is 1:1.5-2; The reaction temperature in step (1) is 25-30°C.

2. The method for preparing modified psicose according to claim 1, characterized in that: The concentration of the psicose solution in step (1) is 40-60 wt %.

3. The method for preparing modified psicose according to claim 1, characterized in that: The pH value in step (1) is adjusted using sodium carbonate.

4. The method for preparing modified psicose according to claim 1, characterized in that: The stirring rate of the reaction in step (1) is 250-350 rpm.

5. The method for preparing modified psicose according to claim 1, characterized in that: The termination in step (2) can be achieved by adjusting the pH value to 5.0-5.

5.

6. The method for preparing modified psicose according to claim 5, characterized in that: The pH value is adjusted with hydrochloric acid.

7. The method for preparing modified psicose according to claim 1, characterized in that: The concentration is performed until no water is evaporated, and the crystallization is performed using isopropanol anti-solvent crystallization.

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