Transformation method of isomaltulose

Abstract

The invention relates to a transformation method of isomaltulose, which comprises the following steps: (1) mixing a sucrose aqueous solution with sucrose isomerase, and stirring to react; (2) when the stirring reaction is carried out, sampling to detect the sucrose conversion condition, and adjusting the conversion temperature according to the detection result; and (3) ending the reaction when the sucrose conversion rate is greater than or equal to 98%. According to the method, high-purity conversion of isomaltulose is achieved by presetting the temperature change program, generation of by-products is greatly reduced, conversion equilibrium is promoted by variable-temperature conversion to incline towards isomaltulose, the product conversion rate is higher, and meanwhile generation of side reactions and hydrolysis of cane sugar are avoided as much as possible.

Description

Technical Field

[0001] The invention relates to the technical field of sugar production, and in particular to a method for converting isomaltulose. Background Art

[0002] Isomaltulose, i.e. 6-O-α-D-pyranosyl-D-fructose, is also known as palatinose. Isomaltulose is produced by fructose and glucose connected by α-1,6-glycosidic bonds to obtain a dextrorotatory disaccharide, which exists in a white crystalline state in the natural state. The sweetness of isomaltulose is about 50% of sucrose, and it has no peculiar smell and stable sweetness. When isomaltulose is boiled in a high temperature environment (120°C) for a period of time, the sweetness hardly changes. Isomaltulose is easily soluble in water, and its solubility gradually increases with the increase of temperature. Compared with sucrose, isomaltulose has stronger acid resistance. After 20g / dL of sucrose and isomaltulose are treated in a boiling water bath under acidic conditions for a certain period of time, the sucrose is completely hydrolyzed, while isomaltulose has almost no change.

[0003] Isomaltulose has similar physical properties and taste to sucrose. It also has anti-dental caries and prebiotic effects. It can also improve brain function, enhance human memory, inhibit fat accumulation and prevent obesity. It does not cause increased blood sugar and insulin levels. It is an ideal alternative sweetener to sucrose and is also an internationally recognized safe sucrose substitute. Therefore, it is widely used in candy, chocolate, baked products, dairy products and foods for special groups, and has good application prospects in the food industry.

[0004] CN101591689A discloses a method for converting sucrose into isomaltulose by a bioenzymatic method, and the process comprises: (1) fully converting a sucrose solution and immobilized cells having α-glucosyltransferase in a conversion tank to obtain a conversion liquid containing isomaltulose and other miscellaneous sugars, wherein the isomaltulose content in the conversion liquid reaches more than 85%; (2) passing the obtained conversion liquid into a miscellaneous sugar removal reaction tank containing immobilized brewer's yeast to remove most of the miscellaneous sugars other than isomaltulose in the conversion liquid; and (3) subjecting the conversion liquid after the miscellaneous sugars are removed to decolorization, filtration, ion exchange, concentration, high-temperature vacuum crystallization, and centrifugation to remove residual miscellaneous sugars and other impurities to obtain isomaltulose crystals.

[0005] In summary, how to improve the conversion rate of sucrose and obtain high-purity isomaltulose has become one of the urgent problems to be solved in this field. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for converting isomaltulose, using sucrose isomerase to isomerize sucrose to obtain isomaltulose, and a high-purity conversion of isomaltulose is achieved by presetting a temperature change program, greatly reducing the generation of by-products. The temperature-variable conversion can promote the conversion balance to tilt toward isomaltulose, and the product conversion rate is higher.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for converting isomaltulose, the method comprising the following steps:

[0009] (1) mixing a sucrose aqueous solution with sucrose isomerase and stirring for reaction;

[0010] (2) While the stirring reaction is in progress, sampling is performed to detect the sucrose conversion, and the conversion temperature is adjusted according to the detection result. The adjustment of the conversion temperature according to the detection result specifically includes:

[0011] (I) When 20%≤sucrose conversion rate<30%, conversion temperature T=70x+4;

[0012] (II) When 30%≤sucrose conversion rate<50%, conversion temperature T=75x+2.5;

[0013] (III) When 50%≤sucrose conversion rate<80%, conversion temperature T=40-25t;

[0014] (IV) When 80%≤sucrose conversion rate<95%, conversion temperature T=200x-145;

[0015] (V) When 95%≤sucrose conversion rate<98%, conversion temperature T=60;

[0016] Wherein, T is the conversion temperature, in °C; x is the sucrose conversion rate; t is the time, in h, with the sucrose conversion rate of 50% as the initial time 0h, and the value range of t is 0≤t≤1;

[0017] (3) The reaction is terminated when the sucrose conversion rate is ≥98%.

[0018] The specific point value of the sucrose conversion rate in the above-mentioned 20%≤sucrose conversion rate<30% can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28% or 29%, etc.

[0019] The specific point value of the sucrose conversion rate in the above 30%≤sucrose conversion rate<50% can be 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48% or 49%, etc.

[0020] The specific point value of the sucrose conversion rate in the above 50%≤sucrose conversion rate<80% can be 50%, 53%, 56%, 59%, 62%, 65%, 68%, 71%, 74%, 77% or 79%, etc.

[0021] The specific point value of the sucrose conversion rate in the above 80%≤sucrose conversion rate<95% can be 80%, 82%, 84%, 86%, 88%, 90%, 92%, 93% or 94%, etc.

[0022] The specific point value of the sucrose conversion rate in the above 95%≤sucrose conversion rate<98% can be 95%, 95.5%, 96%, 96.5%, 97% or 97.5%, etc.

[0023] The specific point value of the sucrose conversion rate in the above sucrose conversion rate ≥98% can be 98%, 98.5%, 99%, 99.5% or 100%, etc.

[0024] The value range of the above t value is 0≤t≤1, and the specific point value of the t value can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc.

[0025] Step (2) of the present invention involves sampling to detect the sucrose conversion. According to the daily operating experience of those skilled in the art, it can be known that the time required for the sucrose conversion rate to reach about 20% is about 10 hours. Therefore, no sampling is performed before the sucrose conversion rate is less than 20%, and sampling begins 1 hour after reaching the empirical value. The temperature of the conversion system is adjusted according to the preset temperature change rate. When the new conversion temperature is reached, the conversion liquid is sampled again to determine the sucrose conversion rate, thereby obtaining the next conversion temperature. When 50%≤sucrose conversion rate<80%, the sucrose conversion rate is measured every 1 hour until the sucrose conversion rate is ≥80%.

[0026] The present invention uses sucrose isomerase to isomerize sucrose to obtain isomaltulose, and a high-purity conversion of isomaltulose is achieved by presetting a temperature change program, thereby greatly reducing the generation of by-products. The temperature-variable conversion can promote the conversion balance to tilt toward isomaltulose, and the product conversion rate is higher. As the conversion process proceeds, the conversion temperature is changed to achieve higher production efficiency, while avoiding the generation of side reactions and the hydrolysis of sucrose as much as possible.

[0027] The sucrose isomerase used in the present invention may be in a solid or liquid state.

[0028] The calculation method of the sucrose conversion rate of the present invention is as follows: during the conversion of sucrose to isomaltulose, sampling is performed to detect the content of each component in the reaction solution, and the sucrose content at this time is obtained, and the sucrose conversion rate can be obtained by dividing it by the initial amount of sucrose added.

[0029] When the sucrose conversion rate is 50%≤80% and t=1, the conversion temperature T is 15°C, and then the temperature is maintained constant until the sucrose conversion rate reaches 80%.

[0030] Preferably, the mass percentage of sucrose in the sucrose aqueous solution is 30% to 75% (for example, it can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or 75%, etc.).

[0031] Preferably, the ratio of sucrose to sucrose isomerase in the sucrose aqueous solution is 1g:(200-700)U.

[0032] The specific point values ​​of the above-mentioned (200~700)U can be 200U, 250U, 300U, 350U, 400U, 450U, 500U, 550U, 600U, 650U or 700U, etc.

[0033] Preferably, the stirring speed of the stirring reaction is 10 to 300 rpm (for example, it may be 10 rpm, 20 rpm, 50 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm or 300 rpm, etc.).

[0034] Preferably, the initial temperature of the stirring reaction is 15-20°C (for example, it may be 15°C, 16°C, 17°C, 18°C, 19°C or 20°C, etc.).

[0035] Preferably, adjusting the conversion temperature comprises: when the conversion temperature changes according to the sucrose conversion rate, adjusting the conversion temperature by a uniform heating or cooling method.

[0036] When 20%≤sucrose conversion rate<50% or 80%≤sucrose conversion rate<95% in the present invention, that is, the conditions (I), (II) or (IV) for adjusting the conversion temperature according to the test results provided by the present invention, the conversion temperature changes according to the sucrose conversion rate.

[0037] When the sucrose conversion rate of 50% ≤ sucrose conversion rate < 80% of the present invention, that is, the condition (III) of adjusting the conversion temperature according to the test results provided by the present invention, the conversion temperature changes according to time, and the cooling rate of the isomaltulose conversion system of the present invention is naturally obtained at this time is 25°C / h.

[0038] Preferably, the uniform heating rate is 1.5 to 2.5°C / h (for example, 1.5°C / h, 1.7°C / h, 1.9°C / h, 2°C / h, 2.1°C / h, 2.3°C / h or 2.5°C / h, etc.).

[0039] Preferably, the cooling rate of the uniform cooling is 1.5 to 2.5°C / h (for example, it may be 1.5°C / h, 1.7°C / h, 1.9°C / h, 2°C / h, 2.1°C / h, 2.3°C / h or 2.5°C / h, etc.).

[0040] Preferably, the detection method in adjusting the conversion temperature according to the detection result comprises liquid chromatography.

[0041] Preferably, after the reaction is completed, a conversion solution is obtained, and the conversion solution contains isomaltulose, trehalulose, isomelizitose, glucose, fructose and sucrose.

[0042] Preferably, the mass percentage of the isomaltulose is ≥ 95% (for example, it may be 95%, 96%, 97%, 98%, 99% or 100%, etc.).

[0043] In a second aspect, the present invention provides use of the conversion method described in the first aspect in preparing high-purity isomaltulose.

[0044] Other specific point values ​​within the above numerical ranges can be selected and will not be described in detail here.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention provides a method for converting isomaltulose, using sucrose isomerase to isomerize sucrose to obtain isomaltulose, and a temperature change program is preset to achieve high-purity conversion of isomaltulose, greatly reducing the generation of by-products. The temperature-variable conversion can promote the conversion balance to tilt toward isomaltulose, and the product conversion rate is higher. As the conversion process proceeds, the conversion temperature is changed to achieve higher production efficiency, while avoiding the generation of side reactions and the hydrolysis of sucrose as much as possible. DETAILED DESCRIPTION

[0047] To further illustrate the technical means and effects of the present invention, the present invention is further described below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention.

[0048] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0049] Example 1

[0050] This embodiment provides a method for converting isomaltulose, comprising the following steps:

[0051] (1) A sucrose aqueous solution containing 60% sucrose by mass is mixed with sucrose isomerase, the ratio of sucrose to sucrose isomerase in the sucrose aqueous solution is 1 g:600 U, the mixture is stirred at 150 rpm, the initial temperature is 18° C., and the conversion temperature is then adjusted according to a preset temperature control program.

[0052] (2) Continue stirring and take samples to test the sucrose conversion. The sucrose content at this time is divided by the initial sucrose addition amount to obtain the sucrose conversion rate. Adjust the conversion temperature according to the test results. The conversion temperature is adjusted according to the following conditions:

[0053] (I) When 20%≤sucrose conversion rate<30%, conversion temperature T=70x+4;

[0054] (II) When 30%≤sucrose conversion rate<50%, conversion temperature T=75x+2.5;

[0055] (III) When 50%≤sucrose conversion rate<80%, conversion temperature T=40-25t;

[0056] (IV) When 80%≤sucrose conversion rate<95%, conversion temperature T=200x-145;

[0057] (V) When 95%≤sucrose conversion rate<98%, conversion temperature T=60;

[0058] Wherein, T is the conversion temperature in °C; x is the sucrose conversion rate; t is the time in h, with the sucrose conversion rate of 50% as the initial time 0h, and the value range of t is 0≤t≤1; the heating and cooling rates of conditions (Ⅰ), (Ⅱ) and (Ⅳ) are 2℃ / h.

[0059] (3) When the sucrose conversion rate is ≥98%, the reaction is terminated to obtain the conversion solution.

[0060] Example 2

[0061] This embodiment provides a method for converting isomaltulose, comprising the following steps:

[0062] (1) A sucrose aqueous solution containing 30% by weight of sucrose is mixed with sucrose isomerase, the ratio of sucrose to sucrose isomerase in the sucrose aqueous solution is 1 g:700 U, the mixture is stirred at 100 rpm, the initial temperature is 15° C., and the conversion temperature is then adjusted according to a preset temperature control program.

[0063] (2) Continue stirring, take samples to detect the sucrose conversion, and divide the sucrose content at this time by the initial sucrose addition amount to obtain the sucrose conversion rate. Adjust the conversion temperature according to the test results. The conversion temperature is adjusted according to the conditions provided in Example 1. The heating and cooling rates of conditions (I), (II) and (IV) are 2.5°C / h.

[0064] (3) When the sucrose conversion rate is ≥98%, the reaction is terminated to obtain the conversion solution.

[0065] Example 3

[0066] This embodiment provides a method for converting isomaltulose, comprising the following steps:

[0067] (1) A sucrose aqueous solution containing 75% by weight of sucrose is mixed with sucrose isomerase, the ratio of sucrose to sucrose isomerase in the sucrose aqueous solution is 1 g:200 U, the mixture is stirred at 300 rpm, the initial temperature is 20° C., and the conversion temperature is then adjusted according to a preset temperature control program.

[0068] (2) Continue stirring, take samples to detect the sucrose conversion, and divide the sucrose content at this time by the initial sucrose addition amount to obtain the sucrose conversion rate. Adjust the conversion temperature according to the test results. The conversion temperature is adjusted according to the conditions provided in Example 1. The heating and cooling rates of conditions (I), (II) and (IV) are 1.5°C / h.

[0069] (3) When the sucrose conversion rate is ≥98%, the reaction is terminated to obtain the conversion solution.

[0070] Comparative Example 1

[0071] The comparative example provides a method for converting isomaltulose, comprising the following steps: mixing a sucrose aqueous solution containing 60% sucrose by mass with sucrose isomerase, wherein the ratio of sucrose to sucrose isomerase in the sucrose aqueous solution is 1 g: 600 U, reacting at 18° C. and 100 rpm with stirring for 72 h, and completing the conversion when the sucrose conversion rate is ≥98% to obtain a conversion solution.

[0072] Comparative Example 2

[0073] The comparative example provides a method for converting isomaltulose, comprising the following steps: mixing a sucrose aqueous solution containing 60% sucrose by mass with sucrose isomerase, wherein the ratio of sucrose to sucrose isomerase in the sucrose aqueous solution is 1 g: 600 U, stirring and reacting at 25° C. and 100 rpm for 48 h, and completing the conversion when the sucrose conversion rate is ≥98% to obtain a conversion solution.

[0074] Comparative Example 3

[0075] The comparative example provides a method for converting isomaltulose, comprising the following steps: mixing a sucrose aqueous solution containing 60% sucrose by mass with sucrose isomerase, wherein the ratio of sucrose to sucrose isomerase in the sucrose aqueous solution is 1 g: 600 U, reacting at 45° C. and 100 rpm with stirring for 30 h, and completing the conversion when the sucrose conversion rate is ≥98% to obtain a conversion liquid.

[0076] Comparative Example 4

[0077] This comparative example provides a method for converting isomaltulose, which is different from Example 1 only in that when 20%≤sucrose conversion rate≤30%, the conversion temperature remains unchanged, that is, when 0%≤sucrose conversion rate≤30%, the conversion temperature is 18°C.

[0078] Comparative Example 5

[0079] This comparative example provides a method for converting isomaltulose, which is different from Example 1 only in that when the sucrose conversion rate is 30%≤≤50%, the conversion temperature remains unchanged at 25°C.

[0080] Comparative Example 6

[0081] This comparative example provides a method for converting isomaltulose, which is different from Example 1 only in that when the sucrose conversion rate is 50%≤≤80%, the conversion temperature remains unchanged at 15°C.

[0082] Comparative Example 7

[0083] This comparative example provides a method for converting isomaltulose, which differs from Example 1 only in that when the sucrose conversion rate is 80%≤≤95%, the conversion temperature remains unchanged at 15°C.

[0084] Comparative Example 8

[0085] This comparative example provides a method for converting isomaltulose, which differs from Example 1 only in that when the sucrose conversion rate is 80%≤≤95%, the conversion temperature remains unchanged at 45°C.

[0086] Test Example 1

[0087] In this test example, sucrose was converted into isomaltulose using the methods provided in Examples 1-3 and Comparative Examples 1-8 to obtain a conversion liquid. The components of the conversion liquid and the mass proportion of each component were determined by high performance liquid chromatography. The results are shown in Table 1.

[0088] Table 1

[0089] Group Isomaltulose Trehalulose Isomezitose glucose fructose sucrose Example 1 96.2％ 0.8％ 0.6％ 1.0％ 1.1％ 0.3％ Example 2 95.4％ 0.9％ 0.7％ 1.1％ 1.4％ 0.5％ Example 3 95.6％ 1.0％ 0.6％ 1.2％ 1.3％ 0.3％ Comparative Example 1 89.1％ 5.2％ 0.5％ 1.7％ 1.7％ 1.8％ Comparative Example 2 90.5％ 2.8％ 1.6％ 1.7％ 2.2％ 1.2％ Comparative Example 3 89.0％ 2.3％ 4.1％ 1.7％ 2.1％ 0.8％ Comparative Example 4 93.1％ 1.5％ 1.3％ 1.6％ 1.7％ 0.8％ Comparative Example 5 91.9％ 2.0％ 1.5％ 1.7％ 2.0％ 0.9％ Comparative Example 6 91.4％ 2.1％ 1.9％ 1.6％ 1.9％ 1.1％ Comparative Example 7 93.4％ 1.6％ 1.7％ 1.4％ 1.5％ 0.4％ Comparative Example 8 94.1％ 1.1％ 1.3％ 1.4％ 1.5％ 0.6％

[0090] From Table 1, we can conclude that:

[0091] (1) Comparison of Example 1 with Comparative Examples 1-3 shows that Comparative Example 1 is converted under low temperature and constant temperature conditions, the conversion rate is slow, and the content of conversion by-products is also high, which seriously affects the separation, crystallization and product purity of the subsequent products; Comparative Example 2 significantly increases the conversion rate and proportion of isomaltulose by increasing the conversion temperature, but the proportion is still less than 95%; Comparative Example 3 further increases the conversion temperature, and the conversion rate is significantly improved, but sucrose is severely decomposed, and there are more by-products, and the generation rate of isomaltulose is also significantly reduced; while Example 1 increases the conversion rate and reduces the generation of by-products by a temperature change method, and the sucrose conversion rate is higher than 95%.

[0092] (2) By comparing Example 1 with Comparative Examples 4-8, it can be seen that the staged temperature change method provided by the present invention promotes the conversion balance to tilt towards isomaltulose, the product conversion rate is higher, the isomaltulose yield is greatly improved compared with the isomaltulose yield under constant temperature conversion conditions, and the generation of by-products is also controlled. Replacing any one of the conditions will reduce the yield of isomaltulose.

[0093] In summary, the present invention provides a method for converting isomaltulose, using sucrose isomerase to isomerize sucrose to obtain isomaltulose, and a high-purity conversion of isomaltulose is achieved by presetting a temperature change program, greatly reducing the generation of by-products. The temperature-variable conversion can promote the conversion balance to tilt toward isomaltulose, and the product conversion rate is higher. As the conversion process proceeds, the conversion temperature is changed to achieve higher production efficiency, while avoiding the generation of side reactions and the hydrolysis of sucrose as much as possible.

[0094] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for converting isomaltulose, characterized in that: The transformation method comprises the following steps: (1) mixing a sucrose aqueous solution with sucrose isomerase and stirring for reaction; (2) While the stirring reaction is in progress, sampling is performed to detect the sucrose conversion, and the conversion temperature is adjusted according to the detection result. The adjustment of the conversion temperature according to the detection result specifically includes: (I) When 20%≤sucrose conversion rate<30%, conversion temperature T=70x+4; (II) When 30%≤sucrose conversion rate<50%, conversion temperature T=75x+2.5; (III) When 50%≤sucrose conversion rate<80%, conversion temperature T=40-25t; (IV) When 80%≤sucrose conversion rate<95%, conversion temperature T=200x-145; (V) When 95%≤sucrose conversion rate<98%, conversion temperature T=60; Wherein, T is the conversion temperature, in °C; x is the sucrose conversion rate; t is the time, in h, with the sucrose conversion rate of 50% as the initial time 0h, and the value range of t is 0≤t≤1; (3) The reaction was terminated when the sucrose conversion rate was ≥98%.

2. The conversion method according to claim 1, characterized in that The mass percentage of sucrose in the sucrose aqueous solution is 30% to 75%.

3. The conversion method according to claim 1 or 2, characterized in that The ratio of sucrose to sucrose isomerase in the sucrose aqueous solution is 1g:(200-700)U.

4. The transformation method according to any one of claims 1 to 3, characterized in that The stirring speed of the stirring reaction is 10 to 300 rpm.

5. The transformation method according to any one of claims 1 to 4, characterized in that The initial temperature of the stirring reaction is 15-20°C.

6. The transformation method according to any one of claims 1 to 5, characterized in that The adjusting of the conversion temperature comprises: when the conversion temperature changes according to the sucrose conversion rate, adjusting the conversion temperature by a uniform heating or uniform cooling method.

7. The conversion method according to claim 6, characterized in that The uniform heating rate is 1.5-2.5°C / h; Preferably, the uniform cooling rate is 1.5-2.5°C / h.

8. The transformation method according to any one of claims 1 to 7, characterized in that The detection method in adjusting the conversion temperature according to the detection result includes liquid chromatography.

9. The transformation method according to any one of claims 1 to 8, characterized in that After the reaction is completed, a conversion solution is obtained, wherein the conversion solution contains isomaltulose, trehalulose, isomelizitose, glucose, fructose and sucrose; Preferably, the mass percentage of isomaltulose is ≥ 95%.

10. Use of the conversion method according to any one of claims 1 to 9 in the preparation of high-purity isomaltulose.