Sugar-free high-functionality isomaltooligosacharide and preparation method thereof

Abstract

The invention discloses sugar-free high-functionality isomaltooligosacharide and a preparation method thereof, and belongs to the technical field of functional sugar manufacturing. The invention discloses a preparation method of sugar-free high-functionality isomaltooligosacharide, which comprises the following steps of: converting starch into coarse ultrahigh maltose syrup by using high-temperature-resistant alpha-amylase, barley-beta-amylase and pullulanase, further refining the coarse ultrahigh maltose syrup through deslagging, decolorizing and ion exchange, adding glucosylase, and carrying out high-temperature hydrolysis to obtain the sugar-free high-functionality isomaltooligosacharide. And then purifying the crude isomaltooligosacharide by adopting a nanofiltration membrane, and removing glucose in the sugar liquid. The content of glucose and maltose in the prepared isomaltose hypgather is lower than 0.5%, the isomaltose hypgather meets the requirements of the current market for healthy and sugar-free high-functional products, the content of effective sugar IG < 2 + > P + IG3 is larger than or equal to 90%, and the product has higher functional components which are two times that of the current market products.

Description

Technical Field

[0001] This invention relates to the field of functional sugar manufacturing technology, and more specifically to a sugar-free, highly functional isomaltooligosaccharide and its preparation method. Background Technology

[0002] Isomaltooligosaccharide (IMO) is a functional oligosaccharide, also known as isomaltooligosaccharide, branched oligosaccharide, or isomaltooligosaccharide. It is an oligosaccharide composed of 2-5 glucose residues linked by α-1,6 glycosidic bonds. The main components of isomaltooligosaccharide are isomaltose, isomalttriose, panose, isomaltotetraose, and higher oligosaccharides. Among them, isomaltose (IG2), panose (P), and isomalttriose (IG3) are the main components that contribute to the functionality of isomaltooligosaccharide. Their content reflects the quality of the product, its prebiotic effects, and also affects the product's price and application prospects.

[0003] Isomaltooligosaccharides can promote the proliferation of bifidobacteria in the intestines, inhibit the formation of harmful bacteria and putrefactive substances, increase vitamin content, and enhance the body's immunity. At the same time, they are difficult to digest by gastric digestive enzymes, have low sweetness and low calories, and will not raise blood sugar or blood lipids. Furthermore, they are not utilized by streptococci in the oral cavity or broken down by oral enzymes, thus preventing tooth decay. Therefore, they are widely used in food, beverages, and health products.

[0004] Currently, the classic process for producing type 90 isomaltooligosaccharide (OMOS) both domestically and internationally uses starch as raw material. This involves a two-stage jet liquefaction process, liquefying the starch slurry. The liquefied starch is then further processed by α-amylase or β-amylase to produce maltose syrup. α-glucosidase then performs glycosyl conversion to generate isomaltooligosaccharide. The product is then refined through filtration, decolorization, and desalting, followed by chromatographic separation and purification, and finally concentration to obtain the final product. With the improvement of people's living standards and increased health awareness, people are paying more attention to "sugar-free" products. However, isomaltooligosaccharide produced using the classic process inevitably contains impurities such as maltose and glucose. The presence of these impurities not only significantly reduces the content of functional components in isomaltooligosaccharide and weakens the physiological functions of functional oligosaccharides, but also fails to meet people's pursuit of "sugar-free" products. Therefore, developing a sugar-free, high-functionality isomaltooligosaccharide has become an important research direction for the production of high-purity isomaltooligosaccharide.

[0005] Patent document CN108546724A provides a method for preparing high-purity isomaltooligosaccharide. In this method, starch liquefaction is first saccharified under the action of β-amylase and pullulanase. Then, transglycosylase is used to change the bonding position of the saccharified molecular structure, converting it into isomaltooligosaccharide with a branched structure. Subsequently, glucose is removed from the components by membrane filtration, reducing the glucose content to 8-10% and increasing the isomaltooligosaccharide content from 50% to over 80%. Then, active yeast fermentation is used to reduce the glucose content to below 1%. After purification, the isomaltooligosaccharide content reaches over 92%. The above methods are complex, have low production efficiency, and high fermentation broth treatment costs. Secondly, even if the above processes are used, the glucose content can only be reduced to about 1% at the very least, and the maltose content percentage is not mentioned, which does not meet the "sugar-free" standard. The effective sugar (IG2+P+IG3) content of isomaltooligosaccharide extracted by this process can only reach about 48%, and the purity of isomaltooligosaccharide is about 92%, which can be further improved.

[0006] Therefore, providing a sugar-free, highly functional isomaltooligosaccharide and its preparation method is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a sugar-free, high-functional isomaltooligosaccharide and its preparation method. The glucose + maltose content of the prepared isomaltooligosaccharide can be guaranteed to be less than 0.5%, and the IG2 + P + IG3 content is more than 90%. At the same time, the method has the advantages of low production cost, high production efficiency, and suitability for industrial production.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention first converts corn starch into ultra-high maltose syrup. The ultra-high maltose syrup is then further refined by removing residue, decolorizing, and ion exchange, and glucose transglycosylase is added to obtain crude isomaltooligosaccharide. Then, nanofiltration membrane is used to purify the crude isomaltooligosaccharide to remove glucose from the sugar solution. Finally, sugar-free high-functionality isomaltooligosaccharide is obtained by evaporation and concentration.

[0010] A method for preparing sugar-free, highly functional isomaltooligosaccharide includes the following steps: (1) Using corn starch as raw material, pure water is added to corn starch to obtain starch milk with a concentration of 15-17 Baume degrees, the pH is adjusted to 5.5-6.0, heat-resistant α-amylase is added, and liquefied liquid is obtained by one spray and two sprays. The thermoresistant α-amylase has an enzyme activity of 36500 U / ml and is added at a rate of 0.1 ~ 0.7 L / ton of dry matter. (2) Adjust the pH of the liquefied liquid obtained in step (1) to 5.5~6.0, add barley-β-amylase and pullulanase, and perform saccharification reaction at 53~58℃ for 25~30h. Then, raise the temperature to 95~100℃ to inactivate the enzymes and obtain crude ultra-high maltose syrup. The barley β-amylase has an enzyme activity of 13000 U / ml and is added at a rate of 0.25 ~ 0.35 L / ton of dry matter; the pullulanase has an enzyme activity of 1000 U / ml and is added at a rate of 0.45 ~ 0.55 L / ton of dry matter. (3) The crude ultra-high maltose syrup obtained in step (2) is subjected to slag removal, decolorization, and ion exchange to obtain refined ultra-high maltose syrup; (4) Adjust the pH of the refined ultra-high maltose syrup obtained in step (3) to 5.5~6.0, add glucose transglycosylase, carry out secondary saccharification, react at 57~63℃ for 25~30h, raise the temperature to 85~90℃ to inactivate the enzyme, and obtain crude isomaltooligosaccharide syrup. The glucose transaminase has an enzyme activity of 300,000 U / ml and is added at a rate of 0.8 ~ 1.0 L / ton of dry matter. (5) The crude isomaltooligosaccharide syrup obtained in step (4) is filtered by nanofiltration membrane, and the filtrate after membrane filtration is taken as refined isomaltooligosaccharide syrup. (6) The refined isomaltooligosaccharide syrup obtained in step (5) is evaporated and concentrated to obtain sugar-free high-functionality isomaltooligosaccharide.

[0011] Furthermore, the temperature of the first spray in step (1) is 105~115℃; the temperature of the second spray is 125~130℃.

[0012] Furthermore, the maltose content in the crude ultra-high maltose syrup described in step (2) is >90%.

[0013] Further, the slag removal and decolorization steps in step (3) are as follows: the crude ultra-high maltose syrup is filtered through a plate and frame filter press to remove slag and obtain a liquid; activated carbon is added to the liquid for decolorization, the amount of activated carbon added is 1‰~3‰, the temperature is 60~80℃, and the time is 15~30min; after decolorization, it is filtered through a plate and frame filter press to obtain a clear sugar solution.

[0014] Furthermore, the ion exchange in step (3) uses a strong acidic cation-weak basic anion exchange resin, and the operating temperature is 35 ~ 45℃.

[0015] Furthermore, in step (5), the solid content of the feed material of the nanofiltration membrane is 15-20%, the feed pressure is 1.5-2.5 MPa, and the pore size of the nanofiltration membrane is 250D; the content of glucose + maltose in the refined isomaltooligosaccharide is ≤0.5%, and the content of effective sugar IG2+P+IG3 is ≥90%.

[0016] Furthermore, the method described yields a sugar-free, highly functional isomaltooligosaccharide.

[0017] Furthermore, the glucose + maltose content in the sugar-free high-functional isomaltooligosaccharide is ≤0.5%, and the effective sugar IG2 + P + IG3 content is ≥90%.

[0018] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a sugar-free, high-functionality isomaltooligosaccharide and its preparation method, which has the following beneficial effects: (1) In this invention, ultra-high maltose is first prepared, and glucose transglycosylase is used to hydrolyze the α-1,4 glycosidic bond of maltose. At the same time, the glucose residue of the hydrolysis product is catalyzed to be linked to the α-1,6 position of another glucose molecule to form isomaltose. This method can produce qualified type 90 oligoisomaltose in one go. Its effective sugar IG2+P+IG3 content is >45%, and the obtained oligoisomaltose does not contain maltose.

[0019] (2) The present invention purifies and refines the crude isomaltooligosaccharide by nanofiltration. The content of glucose + maltose in the obtained isomaltooligosaccharide is less than 0.5%, and the content of effective sugar IG2 + P + IG3 is ≥90%, and the purity is ≥95%. It is a sugar-free high-functional isomaltooligosaccharide.

[0020] Patent document CN102757990A provides a method for preparing high-purity isomaltooligosaccharide. This method uses continuous simulated moving bed chromatography to separate glucose from isomaltooligosaccharide, thereby improving the purity of isomaltooligosaccharide. However, the simulated moving bed chromatography equipment has high energy consumption, requires frequent regeneration and elution, and the operation process is relatively complex. Furthermore, the effective sugar content of the purified isomaltooligosaccharide is only about 45%, which is relatively low. The method of this invention achieves an effective sugar content of over 90%, which is superior to the method provided in patent document CN102757990A. Detailed Implementation

[0021] 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.

[0022] The activity of thermostable α-amylase is 36,500 U / ml, that of barley β-amylase is 13,000 U / ml, that of pullulanase is 1,000 U / ml, and that of glucose transglycosylase is 300,000 U / ml.

[0023] Example 1 A method for preparing sugar-free, highly functional isomaltooligosaccharide includes the following steps: (1) Add water to corn starch to prepare starch milk with a Baume degree of 15, adjust the pH to 5.5, add 0.1 L / ton dry matter of heat-resistant α-amylase, spray once at 105℃, and then spray twice at 125℃ to obtain liquefied liquid.

[0024] (2) Adjust the pH of the liquefied liquid to 5.5, add barley β-amylase at 0.25 L / ton dry matter and pullulanase at 0.45 L / ton dry matter, and saccharify at 53°C for 30 h. Then, raise the temperature to 95°C to inactivate the enzymes to obtain crude ultra-high maltose syrup.

[0025] (3) The crude ultra-high maltose syrup was filtered through a plate and frame filter press to remove slag and obtain a liquid. Activated carbon was added to the liquid for decolorization at a concentration of 1‰, a temperature of 60℃, and a time of 30 min. After decolorization, the liquid was filtered through a plate and frame filter press to obtain a clear sugar solution. The clear sugar solution was then subjected to a strong acid cation-weak base anion exchange resin at 35℃ to remove metal salts and pigments from the solution, resulting in refined ultra-high maltose syrup.

[0026] (4) Adjust the pH of the refined ultra-high maltose syrup to 5.5, add 0.8 L / ton of dry matter of glucose transglycosylase, react at 57℃ for 30 h, and then heat to 85℃ to inactivate the enzyme to obtain crude isomaltooligosaccharide.

[0027] (5) Dilute the crude isomaltooligosaccharide to a solid content of 15%, and purify it by filtration through a nanofiltration membrane with a pore size of 250D under a pressure of 1.5MPa. The filtrate after purification and filtration is refined isomaltooligosaccharide. The content of glucose + maltose in the refined isomaltooligosaccharide is 0.41%, and the content of effective sugar IG2 + P + IG3 is 90.75%.

[0028] (6) The refined isomaltooligosaccharide is evaporated and concentrated to obtain sugar-free high-functionality isomaltooligosaccharide.

[0029] Example 2 A method for preparing sugar-free, highly functional isomaltooligosaccharide includes the following steps: (1) Add water to corn starch to prepare starch milk with a Baume degree of 17, adjust the pH to 6.0, add 0.7 L / ton dry matter of heat-resistant α-amylase, spray once at 115℃, and then spray twice at 130℃ to obtain liquefied liquid.

[0030] (2) Adjust the pH of the liquefied liquid to 6.0, add 0.35 L / ton dry matter of barley-β-amylase and 0.55 L / ton dry matter of pullulanase, and saccharify at 58°C for 25 h. Then, raise the temperature to 100°C to inactivate the enzymes to obtain crude ultra-high maltose syrup.

[0031] (3) The crude ultra-high maltose syrup was filtered through a plate and frame filter press to remove slag and obtain a liquid. Activated carbon was added to the liquid for decolorization at a concentration of 3‰, a temperature of 80℃, and a time of 15 min. After decolorization, the liquid was filtered through a plate and frame filter press to obtain a clear sugar solution. The clear sugar solution was then subjected to a strong acidic cation-weak base anion exchange resin at 45℃ to remove metal salts and pigments from the solution, resulting in refined ultra-high maltose syrup.

[0032] (4) Adjust the pH of the refined ultra-high maltose syrup to 6.0, add 1.0 L / ton of dry matter of glucose transglycosylase, react at 63℃ for 25 h, and then heat to 90℃ to inactivate the enzyme to obtain crude isomaltooligosaccharide.

[0033] (5) Dilute the crude isomaltooligosaccharide to a solid content of 20%, and purify it by filtration through a nanofiltration membrane with a pore size of 250D under a pressure of 2.5MPa. The filtrate after purification and filtration is refined isomaltooligosaccharide. The content of glucose + maltose in the refined isomaltooligosaccharide is 0.25%, and the content of effective sugar IG2+P+IG3 is 92.41%.

[0034] (6) The refined isomaltooligosaccharide is evaporated and concentrated to obtain sugar-free high-functionality isomaltooligosaccharide.

[0035] Example 3 A method for preparing sugar-free, highly functional isomaltooligosaccharide includes the following steps: (1) Add water to corn starch to prepare starch milk with a Baume degree of 16, adjust the pH to 5.7, add 0.4 L / ton dry matter of heat-resistant α-amylase, spray once at 110℃, and then spray twice at 127℃ to obtain liquefied liquid.

[0036] (2) Adjust the pH of the liquefied liquid to 5.7, add barley-β-amylase at 0.3 L / ton of dry matter and pullulanase at 0.5 L / ton of dry matter, and saccharify at 55°C for 28 h. Then, raise the temperature to 97°C to inactivate the enzymes to obtain crude ultra-high maltose syrup.

[0037] (3) The crude ultra-high maltose syrup was filtered through a plate and frame filter press to remove slag and obtain a liquid. Activated carbon was added to the liquid for decolorization at a concentration of 2‰, a temperature of 70℃, and a time of 25 min. After decolorization, the liquid was filtered through a plate and frame filter press to obtain a clear sugar solution. The clear sugar solution was then subjected to a strong acidic cation-weak base anion exchange resin at 40℃ to remove metal salts and pigments from the solution, resulting in refined ultra-high maltose syrup.

[0038] (4) Adjust the pH of the refined ultra-high maltose syrup to 5.7, add 0.9 L / ton of dry matter of glucose transglycosylase, react at 60℃ for 28 h, and then heat to 87℃ to inactivate the enzyme to obtain crude isomaltooligosaccharide.

[0039] (5) Dilute the crude isomaltooligosaccharide to a solid content of 17%, and purify it by filtration through a nanofiltration membrane with a pore size of 250D under a pressure of 2.0MPa. The filtrate after purification and filtration is refined isomaltooligosaccharide. The glucose + maltose content in the refined isomaltooligosaccharide is 0.32%, and the effective sugar IG2 + P + IG3 content is 91.39%.

[0040] (6) The refined isomaltooligosaccharide is evaporated and concentrated to obtain sugar-free high-functionality isomaltooligosaccharide.

[0041] The content of each sugar in the sugar-free high-functional isomaltooligosaccharides prepared in Examples 1-3 was detected by high performance liquid chromatography. The statistical results of glucose + maltose content, effective sugar (IG2+P+IG3) content and isomaltooligosaccharide purity are shown in Table 1.

[0042] Table 1

[0043] 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 method for preparing sugar-free, highly functional isomaltooligosaccharide, characterized in that, Includes the following steps: (1) Using corn starch as raw material, pure water is added to corn starch to obtain starch milk with a concentration of 15-17 Baume degrees, the pH is adjusted to 5.5-6.0, heat-resistant α-amylase is added, and liquefied liquid is obtained by one spray and two sprays. The thermoresistant α-amylase has an enzyme activity of 36500 U / ml and is added at a rate of 0.1 ~ 0.7 L / ton of dry matter. (2) Adjust the pH of the liquefied liquid obtained in step (1) to 5.5~6.0, add barley-β-amylase and pullulanase, and perform saccharification reaction at 53~58℃ for 25~30h. Then, raise the temperature to 95~100℃ to inactivate the enzymes and obtain crude ultra-high maltose syrup. The barley β-amylase has an enzyme activity of 13000 U / ml and is added at a rate of 0.25 ~ 0.35 L / ton of dry matter; the pullulanase has an enzyme activity of 1000 U / ml and is added at a rate of 0.45 ~ 0.55 L / ton of dry matter. (3) The crude ultra-high maltose syrup obtained in step (2) is subjected to slag removal, decolorization, and ion exchange to obtain refined ultra-high maltose syrup; (4) Adjust the pH of the refined ultra-high maltose syrup obtained in step (3) to 5.5~6.0, add glucose transglycosylase, react at 57~63℃ for 25~30h, and then heat to 85~90℃ to inactivate the enzyme to obtain crude isomaltooligosaccharide syrup. The glucose transaminase has an enzyme activity of 300,000 U / ml and is added at a rate of 0.8 ~ 1.0 L / ton of dry matter. (5) The crude isomaltooligosaccharide syrup obtained in step (4) is filtered by nanofiltration membrane, and the filtrate after membrane filtration is taken as refined isomaltooligosaccharide syrup. (6) The refined isomaltooligosaccharide syrup obtained in step (5) is evaporated and concentrated to obtain sugar-free high-functionality isomaltooligosaccharide.

2. The method for preparing a sugar-free, highly functional isomaltooligosaccharide according to claim 1, characterized in that, The temperature of the first spray in step (1) is 105~115℃; the temperature of the second spray is 125~130℃.

3. The method for preparing a sugar-free, highly functional isomaltooligosaccharide according to claim 1, characterized in that, The crude ultra-high maltose syrup in step (2) has a maltose content of >90%.

4. The method for preparing a sugar-free, highly functional isomaltooligosaccharide according to claim 1, characterized in that, The deslag removal and decolorization steps in step (3) are as follows: the crude ultra-high maltose syrup is filtered through a plate and frame filter press to remove slag and obtain a liquid; activated carbon is added to the liquid for decolorization, with the amount of activated carbon added being 1‰~3‰, the temperature being 60~80℃, and the time being 15~30min; after decolorization, the liquid is filtered through a plate and frame filter press to obtain a clear sugar solution.

5. The method for preparing a sugar-free, highly functional isomaltooligosaccharide according to claim 1, characterized in that, The ion exchange in step (3) uses a strong acidic cation-weak basic anion exchange resin, and the operating temperature is 35 ~ 45℃.

6. The method for preparing a sugar-free, highly functional isomaltooligosaccharide according to claim 1, characterized in that, In step (5), the solid content of the feed for nanofiltration is 15-20%, the feed pressure is 1.5-2.5 MPa, and the pore size of the nanofiltration membrane is 250D; the content of glucose + maltose in the refined isomaltooligosaccharide is ≤0.5%, and the content of effective sugar IG2+P+IG3 is ≥90%.

7. The sugar-free, highly functional isomaltooligosaccharide prepared by the method according to any one of claims 1 to 6.

8. The sugar-free, high-functionality isomaltooligosaccharide according to claim 7, characterized in that, The sugar-free, high-functional isomaltooligosaccharide contains ≤0.5% glucose and ≤90% effective sugars IG2+P+IG3.

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