Preparation method of crystalline fructose

Abstract

The invention provides a preparation method of crystalline fructose, which comprises the following steps: by taking glucose as a raw material, carrying out differential isomerization on glucose isomerase to obtain fructose and glucose mixed liquor, carrying out chromatographic separation on the mixed liquor to obtain high fructose, and carrying out cooling crystallization on the high fructose to finally obtain a high-purity fructose product. The product prepared by the method is high in purity, and the product quality is higher than food-grade and pharmaceutical-grade standards.

Description

Technical Field

[0001] This invention belongs to the fields of food and biopharmaceuticals, and more specifically relates to a method for preparing crystalline fructose. Background Technology

[0002] Fructose, as an important sweetener, has wide applications in many fields such as food, medicine, and health products. It has many advantages such as high sweetness, low calories, and low glycemic index. Compared with traditional sucrose, it is more in line with modern consumers' pursuit of a healthy and low-sugar diet, and the market demand is showing a continuous growth trend.

[0003] Currently, the main industrial methods for preparing fructose are chemical synthesis and enzymatic methods. Chemical synthesis typically requires the use of various chemical reagents and is carried out under relatively harsh reaction conditions. This not only results in a complex production process but also easily generates large amounts of byproducts and waste, placing significant pressure on the environment. Furthermore, fructose products obtained through chemical synthesis often have low purity, requiring complex separation and purification steps, further increasing production costs and making it difficult to meet the demands of large-scale industrial production and the market for high-quality fructose products.

[0004] Enzymatic methods have gradually become the mainstream method for fructose preparation due to their advantages such as mild reaction conditions, high specificity, and environmental friendliness. Among these methods, the process of using glucose as a raw material, utilizing glucose isomerase to differentially isomerize glucose into a mixture of fructose and glucose, and then obtaining high-purity fructose through subsequent separation and purification steps is widely used. However, existing enzymatic fructose preparation processes still have some shortcomings.

[0005] In the isomerization stage, controlling the reaction conditions plays a crucial role in the amount and quality of fructose produced. For example, improper control of factors such as pH, temperature, and metal ion concentration in the reaction system can lead to a decrease in the activity of glucose isomerase, thereby affecting the efficiency of the isomerization reaction, reducing the amount of fructose produced, and potentially generating more impurities. Furthermore, the fructose and glucose mixture obtained after the isomerization reaction has similar physicochemical properties, making separation difficult. Currently used separation methods, such as chromatographic separation, can achieve a certain degree of separation, but the separation efficiency still needs improvement, and some fructose may be lost during the separation process, reducing the product yield.

[0006] In the subsequent purification and crystallization stages, the existing process lacks precise control over the concentration, decolorization, and crystallization steps of high fructose. For example, improper concentration control during concentration can affect the subsequent crystallization effect; unreasonable use of activated carbon and decolorization time during decolorization can lead to incomplete decolorization or excessive fructose loss; and inaccurate control of cooling rate and crystallization temperature during crystallization can result in unsatisfactory crystal morphology and particle size distribution, thus affecting the quality and purity of the final product.

[0007] In summary, existing fructose preparation methods suffer from numerous problems in key stages such as reaction condition control, separation and purification, and crystallization, resulting in low product purity, low yield, and high production costs, making it difficult to meet the growing market demand for high-quality crystalline fructose. Therefore, developing an efficient, environmentally friendly method for preparing high-purity crystalline fructose is of significant practical importance. Summary of the Invention

[0008] In view of this, the present invention provides a method for preparing crystalline fructose, which can effectively improve the total yield and reduce energy consumption.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing crystalline fructose includes: using glucose as a raw material, performing differential isomerization with glucose isomerase to obtain a mixture of fructose and glucose, separating the mixture by chromatography to obtain high fructose, and then crystallizing the high fructose by cooling to finally obtain the fructose product.

[0010] Preferably, the above-mentioned method for preparing crystalline fructose specifically includes the following steps: (1) Ingredients: Add deionized water or dilute sugar solution to the sugar dissolving tank, and then pour glucose into the sugar dissolving tank for sugar dissolving treatment; (2) First decolorization: The dissolved sugar is put into the decolorization tank, activated carbon is added for decolorization, and after decolorization, it is filtered and then put into the isomerization heating tank. (3) Isomerization: Add magnesium sulfate and sodium metabisulfite, then adjust the pH to 7.0-8.5, heat and then enter the isomerization column for isomerization treatment; (4) Exchange: The isomerized feed solution enters the ion exchange column for desalination; (5) Separation: The exchanged feed solution enters the chromatographic separation to obtain glucose solution and high fructose; (6) Evaporation: The concentration of high fructose is increased by vacuum evaporation at 70-90℃, and the high fructose concentration index is ≥60%; (7) Secondary decolorization and filtration: High fructose is fed into a decolorization tank, and activated carbon with a dry weight of 0.5-5 kg / t is added for decolorization. The decolorized material is then filtered through a filter. (8) Evaporation: After decolorization, the material enters a multi-effect evaporator and is evaporated to a concentration of 80-90%; (9) Crystallization: The steamed liquid is pumped into a continuous crystallization tank and crystallized by continuous cooling. When the liquid temperature drops below 25°C, it enters the centrifugation step. (10) Centrifugation: The crystallized liquid enters a centrifuge and is separated by centrifugation to obtain a moist filter cake; (11) Drying: The centrifuged filter cake is put into a dryer for drying; (12) Screening and packaging: Screening is carried out using a screening machine. The screened materials are then transported to the packaging station, where they are transported to a quantitative packaging scale for packaging.

[0011] Preferably, the sugar treatment temperature in step (1) is 50-60℃, and the glucose mass percentage concentration is 40-50%.

[0012] Preferably, in step (2), the ratio of activated carbon to precipitated sugar is 4 kg / m³. 3 The decolorization time is 25-35 minutes.

[0013] Preferably, in step (3), the amount of magnesium sulfate added is 0-0.5 g / L; the amount of sodium metabisulfite added is 0-0.3 g / L; sodium hydroxide is used to adjust the pH, the heating temperature is 50-60℃, and the fructose content after isomerization is controlled at 40-50%.

[0014] Preferably, the filter cake in step (10) has 5-hydroxymethylfurfural ≤0.26 and moisture ≤2%.

[0015] Preferably, the drying temperature in step (11) is 70-100℃, and the moisture content after drying is ≤0.5%.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention has the following technical effects: 1. High purity, with impurities below food-grade and pharmaceutical-grade standards.

[0017] 2. High liquidity to meet customer needs. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 The attached figure is a flowchart of the present invention. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 This embodiment provides a method for preparing crystalline fructose, including the following steps: (1) Preparation: First, add deionized water or glucose solution to the sugar dissolving tank, then pour glucose into the sugar dissolving tank. The sugar dissolving temperature is controlled at 55℃ and the concentration is controlled at 49.8%. The volume of the prepared glucose solution is about 4100L.

[0022] (2) Decolorization: The dissolved sugar is put into the decolorization tank, and 1.5KG of activated carbon is added to each tank. After decolorization for 30 minutes, the sugar is filtered and then put into the isomer heating tank.

[0023] (3) Isomerization: Add magnesium sulfate (0.3 g / L) and sodium metabisulfite (0.2 g / L), adjust the pH of the feed solution to 8.0 with sodium hydroxide, heat the feed solution to 53°C, and enter the isomerization column. The fructose content after isomerization is controlled at 45%.

[0024] (4) Exchange: The isomerized feed solution enters the ion exchange column for desalting.

[0025] (5) Separation: The exchanged feed solution enters the chromatographic separation to obtain glucose solution and high fructose (fructose content 96%) at both ends.

[0026] (6) Evaporation: Vacuum evaporation at 70°C increases the concentration of high fructose to 61%.

[0027] (7) Decolorization and filtration: High fructose is fed into a decolorization tank, and activated carbon with a dry weight of 1 kg / t is added. The decolorization time is 30 minutes, and the decolorized material is filtered through a filter.

[0028] (8) Evaporation: The decolorized material enters the multi-effect evaporator and the evaporation concentration is 82%.

[0029] (10) The steamed liquid is fed into a continuous crystallizer and crystallized by continuous cooling. When the liquid temperature drops to 23°C, it can be discharged and centrifuged.

[0030] (11) Centrifugation: The crystallized liquid enters a centrifuge and is separated by centrifugation to obtain a moist filter cake. The filter cake contains 0.2% 5-hydroxymethylfurfural and 1.5% moisture.

[0031] (12) Drying: The centrifuged filter cake is put into a dryer for drying at a temperature of 75°C. The moisture content after drying is 0.2%.

[0032] (13) Screening: Screening is carried out using a screening machine, and the screened materials are transported to the packaging station.

[0033] (14) Packaging: The screened materials are transported to a quantitative packaging scale for packaging.

[0034] Example 2 This embodiment provides a method for preparing pharmaceutical-grade fructose, including the following steps: (1) Preparation: First, add deionized water or glucose solution to the sugar dissolving tank, then pour glucose into the sugar dissolving tank. The sugar dissolving temperature is controlled at 59℃ and the concentration is controlled at 50%. The volume of the prepared glucose solution is about 4000L.

[0035] (2) Decolorization: The dissolved sugar is put into the decolorization tank, and 1.5KG of activated carbon is added to each tank. After decolorization for 30 minutes, the sugar is filtered and then put into the isomer heating tank.

[0036] (3) Isomerization: Add magnesium sulfate (0.3 g / L) and sodium metabisulfite (0.2 g / L), adjust the pH of the feed solution to 8.2 with sodium hydroxide, heat the feed solution to 52°C, and enter the isomerization column. The fructose content after isomerization is controlled at 42%.

[0037] (4) Exchange: The isomerized feed solution enters the ion exchange column for desalting.

[0038] (5) Separation: The exchanged feed solution enters the chromatographic separation stage to obtain glucose solution and high fructose (fructose content 95.6%) at both ends. The glucose solution is returned to the batching process after evaporation, and the high fructose solution is entered into the next process after evaporation.

[0039] (6) Evaporation: Vacuum evaporation at 90°C increases the concentration of high fructose to 61%.

[0040] (7) Decolorization and filtration: High fructose is fed into a decolorization tank, and activated carbon with a dry weight of 2KG / T is added. The decolorization time is 30 minutes, and the decolorized material is filtered through a filter.

[0041] (8) Evaporation: The decolorized material enters the multi-effect evaporator and the evaporation concentration is 85%.

[0042] (9) The steamed liquid is fed into a continuous crystallizer and crystallized by continuous cooling. When the liquid temperature drops to 25°C, it can be discharged and centrifuged.

[0043] (10) Centrifugation: The crystallized liquid enters a centrifuge and is separated by centrifugation to obtain a moist filter cake. The filter cake contains 0.15% 5-hydroxymethylfurfural and 1.8% moisture.

[0044] (11) Drying: The centrifuged filter cake is put into a dryer for drying at a temperature of 80°C. The moisture content after drying is 0.3%.

[0045] (12) Screening: Screening is carried out using a screening machine, and the screened materials are transported to the packaging station.

[0046] (13) Packaging: The screened materials are transported to a quantitative packaging scale for packaging.

[0047] Example 3 This embodiment provides a method for preparing pharmaceutical-grade fructose, including the following steps: (1) Preparation: First, add deionized water or glucose solution to the sugar dissolving tank, then pour glucose into the sugar dissolving tank. The sugar dissolving temperature is controlled at 52℃ and the concentration is controlled at 48%. The volume of the prepared glucose solution is about 4200L.

[0048] (2) Decolorization: The dissolved sugar is put into the decolorization tank, and 1.5KG of activated carbon is added to each tank. After decolorization for 30 minutes, the sugar is filtered and then put into the isomer heating tank.

[0049] (3) Isomerization: Add magnesium sulfate (0.3 g / L) and sodium metabisulfite (0.2 g / L), adjust the pH of the feed solution to 7.9 with sodium hydroxide, heat the feed solution to 54°C, and enter the isomerization column. The fructose content after isomerization is controlled at 43%.

[0050] (4) Exchange: The isomerized feed solution enters the ion exchange column for desalting.

[0051] (5) Separation: The exchanged feed solution enters the chromatographic separation to obtain glucose solution and high fructose (fructose content 96%) at both ends.

[0052] (6) Evaporation: Vacuum evaporation at 80°C increases the concentration of high fructose to 62%.

[0053] (7) Decolorization and filtration: High fructose is fed into a decolorization tank, and 1-5 kg / t of medical activated carbon is added. The decolorization time is 30 minutes, and the decolorized material is filtered through a filter.

[0054] (8) Evaporation: The decolorized material enters the multi-effect evaporator and the evaporation concentration is 85%.

[0055] (9) The steamed liquid is fed into a continuous crystallizer and crystallized by continuous cooling. When the liquid temperature drops to 28°C, it can be discharged and centrifuged.

[0056] (10) Centrifugation: The crystallized liquid enters a centrifuge and is separated by centrifugation to obtain a moist filter cake. The filter cake contains 0.18% 5-hydroxymethylfurfural and 1.7% moisture.

[0057] (11) Drying: The centrifugal filter cake is put into a rotary drum dryer for drying at a temperature of 78°C. The moisture content after drying is 0.2%.

[0058] (12) Screening: Screening is carried out using a screening machine, and the screened materials are transported to the packaging station.

[0059] (13) Packaging: The screened materials are transported to a quantitative packaging scale for packaging.

[0060] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A process for the preparation of crystalline fructose, characterized in that, The application relates to a method for preparing fructose by using glucose as raw material. The method comprises the following steps:

2. The method of claim 1, wherein the crystalline fructose is prepared by the steps of: (1) adding deionized water or glucose solution into a saccharification tank, then pouring glucose into the saccharification tank for saccharification treatment; (2) primary decolorization: the saccharified sugar is poured into a decolorization tank, active carbon is added for decolorization, and the decolorized solution is filtered and poured into an isomerization heating tank; (3) isomerization: magnesium sulfate and sodium metabisulfite are added, then the PH value is adjusted to 7.0-8.5, and the temperature is raised to 50-60 DEG C, and the solution is subjected to isomerization treatment in an isomerization column; (4) exchange: the isomerized solution is subjected to desalination treatment in an ion exchange column; (5) separation: the exchanged solution is subjected to chromatographic separation, and glucose solution and high-fructose are separated; (6) evaporation: the high-fructose is subjected to vacuum evaporation at 70-90 DEG C to increase the concentration, and the high-fructose concentration index is greater than or equal to 60%; (7) secondary decolorization and filtration: the high-fructose is poured into a decolorization tank, 0.5-5 kg / t of active carbon is added for decolorization, and the decolorized solution is filtered by a filter; (8) evaporation: the decolorized solution is subjected to evaporation in an evaporator until the concentration is 80-90%; (9) crystallization: the evaporated solution is poured into a continuous crystallization tank, and continuous cooling is carried out until the solution is cooled to below 25 DEG C, and then centrifugation is carried out; (10) centrifugation: the crystallized solution is subjected to centrifugation in a centrifuge to separate the wet filter cake; (11) drying: the centrifugal filter cake is dried in a drying machine; (12) screening and packaging: the screened material is conveyed to a packaging post, and the screened material is conveyed to a quantitative packaging scale for packaging. In step (1), the saccharification treatment temperature is 55-65 DEG C, and the mass percentage concentration of glucose is 40-50%.

3. The method of claim 2, wherein the crystalline fructose is prepared by the steps of: In step (3), the addition amount of magnesium sulfate is 0-0.5 g / L, the addition amount of sodium metabisulfite is 0-0.3 g / L, the PH value is adjusted by sodium hydroxide, the heating temperature is 50-60 DEG C, and the content of isomerized fructose is controlled to be 40-50%.

4. The method of claim 2, wherein the crystalline fructose is prepared by the steps of: In step (2), the ratio of activated carbon to sugar solution is 2-4 kg / m 3 , and the decolorization time is 25-35 minutes.

5. The method of claim 2, wherein the crystalline fructose is prepared by the steps of: In step (10), the filter cake 5-hydroxymethylfurfural is less than or equal to 0.

26.

6. The method of claim 2, wherein the crystalline fructose is prepared by the steps of: In step (11), the drying temperature is 70-100 DEG C, and the moisture content after drying is less than or equal to 0.5%.

7. The method of claim 2, wherein the crystalline fructose is prepared by the steps of: ​

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