Preparation method of low-viscosity polydextrose

Abstract

The invention discloses a preparation method of low-viscosity polydextrose, and belongs to the technical field of polydextrose preparation. Carrying out multi-stage polymerization reaction on the saccharified liquid, and then refining to obtain low-viscosity polydextrose; the saccharification liquid comprises 10 wt% of glucose, 40 wt% of maltose, 40 wt% of maltotriose, and 10 wt% of tetrasaccharide or above; the multi-stage polymerization reaction specifically comprises the following steps: adding 1wt% of citric acid and 1wt% of sorbitol into the saccharified liquid, and reacting under a high-temperature condition until the content of glucose is 1t; 2 wt%; glucose is supplemented, the adding amount is 10-30 wt% of that of the previous system, and the reaction continues until the glucose content is 1t; 2 wt%; supplementing 20-40wt% of glucose, and continuing the reaction until the content of the glucose is 1t; and 2 wt%. Starch can be adopted as a raw material, and pigment accumulation is reduced by adopting a specific preparation method; meanwhile, the viscosity of the polydextrose is reduced by controlling the size of a molecular chain.

Description

Technical Field

[0001] This invention belongs to the field of polydextrose preparation technology, and specifically relates to a method for preparing low-viscosity polydextrose. Background Technology

[0002] Polydextrose, also known as polydextrin, is a condensation polymer made by mixing glucose, sorbitol, citric acid, or phosphoric acid in a certain proportion and then heating it at high temperature. Its chemical formula is that of a condensation polymer mainly composed of 1,6-glycosidic bonds and random bonds of glucose. In my country, it is listed as a national food additive and is considered a major source of dietary fiber. Polydextrose has the effects of regulating blood lipids, reducing fat accumulation, and controlling weight; regulating blood sugar and preventing diabetes; and acting as a prebiotic to promote the proliferation of beneficial bacteria in the gastrointestinal tract. However, current polydextrose production processes use an acidic, high-temperature environment, making the reaction difficult to control. The resulting polydextrose is dark in color and has a high viscosity, which affects its application in downstream products.

[0003] Currently, the production process of polydextrose mainly uses anhydrous glucose, sorbitol, and citric acid as raw materials, and polymerizes them at high temperatures under vacuum conditions to generate non-digestible components such as α-1,6 bonds. This production process has some drawbacks, primarily that the polymerization reaction is difficult to control, the product still contains a large amount of reducing components such as glucose, the product has a large molecular weight, a dark color, and poor intermolecular flowability, which greatly limits the application range of polydextrose. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for preparing low-viscosity polydextrose, which produces polydextrose with low viscosity and low pigment content.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing low-viscosity polydextrose, comprising the following steps: The saccharified liquid was subjected to a multi-stage polymerization reaction and then purified to obtain low-viscosity polydextrose. The saccharification solution is composed of: 10 wt% glucose, 40 wt% maltose, 40 wt% maltotriose, and 10 wt% tetrasaccharides and above. The multi-stage polymerization reaction specifically refers to: (1) Add 1wt% citric acid and 1wt% sorbitol to the saccharification solution and react under high temperature conditions until the glucose content is <2wt% to complete the first stage of polymerization reaction; (2) Add glucose to the reaction system of step (1) in an amount of 10-30 wt% of the previous system, and continue the reaction until the glucose content is <2 wt%, thus completing the second stage of polymerization reaction; (3) Add 20-40 wt% glucose to the reaction system in step (2) and continue the reaction until the glucose content is <2 wt%.

[0006] Furthermore, the saccharified solution is obtained by enzymatic hydrolysis of starch. Specifically, using starch milk as raw material, the pH is adjusted to 5.1-5.4, and 400 mL / T.DS of β-amylase is added. The mixture is reacted in a 60°C water bath for 8 hours, followed by the addition of 1 L / T.DS of pullulanase to continue the reaction for another 24 hours before the reaction is terminated. This invention uses corn starch as raw material and achieves product-directed processing by controlling the reaction process, thus reducing raw material costs.

[0007] Preferably, the reaction conditions in step (1) are as follows: Reaction temperature: 160℃; Reaction pressure: -0.1 MPa; Reaction time: 10-40 min.

[0008] Preferably, the reaction conditions in step (2) are as follows: Reaction temperature: 160℃; Reaction pressure: -0.1 MPa; Reaction time: 20-40 min.

[0009] Preferably, the reaction conditions in step (3) are as follows: Reaction temperature: 160℃; Reaction pressure: -0.1 MPa; Reaction time: 30-40 min.

[0010] This invention involves adding glucose in batches to control the generation of pigments such as furfural in the reaction system, thus simplifying the purification process of polydextrose.

[0011] As a preferred embodiment, the purification method is as follows: after the polymerization reaction is completed, add alkaline water with pH 7-9 to dissolve the product, and then perform ion exchange desalination, concentration, and drying.

[0012] Preferably, the resins used for ion exchange desalination are, in order, a strong acid cation resin, a weak base anion resin, and a strong base ion resin.

[0013] Furthermore, the drying method is as follows: the refined concentrate is fed into a belt vacuum negative pressure drying device, and sugar-free polydextrose solid is obtained by segmented heating treatment under vacuum negative pressure environment. The first stage temperature is 110℃-120℃, the second stage temperature is 100℃-110℃, the third stage temperature is 90℃-100℃, the fourth stage temperature is 10℃-20℃, and the vacuum degree is -0.08~-0.09MPa. The dried solid was pulverized to obtain polydextrose with low viscosity and high fluidity.

[0014] The belt vacuum negative pressure drying process in the preparation process can achieve rapid and gentle dehydration while lowering the boiling point of water. This avoids the degradation of polydextrose molecular chains and the generation of color-producing impurities such as 5-hydroxymethylfurfural caused by normal pressure and high temperature. It also reduces the hardening and crusting of particle surface, internal molecular aggregation and trace moisture residue, making the finished particle structure more uniform and the surface smoother.

[0015] Preferably, the polydextrose has a viscosity of 600-800 mPa·s.

[0016] It contains at least the following beneficial technical effects: The polydextrose prepared by this invention uses starch as a raw material. When glucose is added in stages, the glucose reacts earlier and at a faster rate. By controlling the glucose content in the reaction substrate, maltose and maltotriose can be reacted preferentially, reducing the reaction rate of polydextrose and controlling the growth rate of molecular chains. This, in turn, reduces the viscosity of polydextrose by controlling the size of the molecular chains. Simultaneously, starch can be used as a raw material, and a specific preparation method can reduce pigment accumulation. Detailed Implementation

[0017] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0018] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0019] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0020] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0021] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0022] Unless otherwise specified, "room temperature" and "normal temperature" in this invention refer to 25±2℃.

[0023] Unless otherwise specified, all raw materials or instruments used in the following embodiments of the present invention are commercially available.

[0024] Detection method: 1) Viscosity testing: GB / T10247-2008 2) Angle of repose testing method: GB11986-89 The starch milk comes from Linqing Deneng Jinyumi Biotechnology Co., Ltd.

[0025] Example 1: S1. Material Preparation 1) Using starch milk as raw material, the pH was adjusted to 5.2, and 400 mL / T.DS β-amylase was added. The mixture was reacted in a 60℃ water bath for 8 hours. Then, 1 L / T.DS pullulanase was added to continue the reaction. The reaction was completed after 24 hours to obtain the saccharified solution. The changes in the composition of the saccharified solution were detected. The contents were: glucose 10 wt%, maltose 40%, maltotriose 40 wt%, and tetrasaccharides or higher 10 wt%. S2. Polymerization reaction 1) Add 1 wt% citric acid and 1 wt% sorbitol to the S1 saccharification solution and carry out the polymerization reaction at 160℃ and -0.1 MPa. After 20 min of reaction, the glucose content is measured to be <2 wt%. 2) Add glucose to the reaction system in 1) at a rate of 15 wt% of the previous amount, and continue the reaction at 160℃ and -0.1 MPa for 30 min. Then, check that the glucose content is <2 wt%. 3) Add 25 wt% glucose to the reaction system in 2), and continue the reaction at 160℃ and -0.1 MPa for 35 min. The glucose content is then measured to be <2 wt%. S3. Dissolution and Filtration: After the polymerization reaction is completed, add alkaline water with pH 7.5 to dissolve and reduce pigment formation. Then, at 50°C, pass the material through the granular activated carbon column at a flow rate of 3 times the carbon column volume / hour. The output index is ≥99% light transmittance.

[0026] S4. Ion Exchange Desalination: The cation column, containing strong acid cation resin, weak base anion resin, and strong base anion resin respectively, are regenerated using conventional methods. Then, the decolorized and filtered syrup is passed sequentially through the cation column, anion column, and anion column at a flow rate of 3 times the resin volume / hour at 40°C for ion exchange desalination.

[0027] S5. Concentration: The liquid after column chromatography is concentrated to a concentration of 70wt% and a viscosity of 670mPa·s (25℃, 70wt% solids) using a four-effect falling film evaporator at a vacuum of -0.08MPa and a liquid temperature of 70℃.

[0028] S6. Drying: The refined concentrate is fed into a belt vacuum dryer, with the vacuum level controlled at -0.09MPa. A four-stage segmented heating process is used: the first stage (feeding zone) is at 115℃ for 23 minutes to quickly remove surface free water; the second stage (core drying zone) is at 105℃ for 18 minutes to remove internal bound water; the third stage (stabilization zone) is at 95℃ for 13 minutes to regulate the particle structure; and the fourth stage (cooling zone) is at 15℃ for 17 minutes to reduce the particle temperature and remove residual trace moisture. S7. Finished Product Powdering: The dried solid is fed into a pulverizer and initially pulverized before being passed through an 80-mesh sieve to obtain polydextrose with low viscosity and high flowability. At this point, the angle of repose of the dried powder is 30.5°.

[0029] Example 2: S1. Material Preparation 1) Using starch milk as raw material, the pH was adjusted to 5.1, and 400 mL / T.DS β-amylase was added. The mixture was reacted in a 60℃ water bath for 8 hours. Then, 1 L / T.DS pullulanase was added to continue the reaction. The reaction was completed after 24 hours to obtain the saccharified solution. The changes in the composition of the saccharified solution were detected. The contents were: glucose 10 wt%, maltose 40%, maltotriose 40 wt%, and tetrasaccharides or higher 10 wt%. S2. Polymerization reaction 1) Add 1 wt% citric acid and 1 wt% sorbitol to the S1 saccharification solution and carry out the polymerization reaction at 160℃ and -0.1 MPa. After 25 min of reaction, the glucose content is detected to be <2 wt%. 2) Add glucose to the reaction system in 1) at a rate of 20 wt% of the previous amount. Continue the reaction at 160℃ and -0.1 MPa for 20 min. Then, check that the glucose content is <2 wt%. 3) Add 30 wt% glucose to the reaction system in 2), and continue the reaction at 160℃ and -0.1 MPa for 30 min. The glucose content is then measured to be <2 wt%. S3. Dissolution and Filtration: After the polymerization reaction is completed, add alkaline water with pH 8 to dissolve and reduce pigment formation. Then, at 50°C, pass the material through the granular activated carbon column at a flow rate of 3 times the carbon column volume / hour. The output index is ≥99% light transmittance.

[0030] S4. Ion Exchange Desalination: The cation column, containing strong acid cation resin, weak base anion resin, and strong base anion resin respectively, are regenerated using conventional methods. Then, the decolorized and filtered syrup is passed sequentially through the cation column, anion column, and anion column at a flow rate of 3 times the resin volume / hour at 35°C for ion exchange desalination.

[0031] S5. The liquid after column chromatography is concentrated to a concentration of 70wt% using a four-effect falling film evaporator at a vacuum of -0.06MPa and a liquid temperature of 50℃. At this point, the viscosity is 710mPa·s (25℃, 70wt% solids).

[0032] S6. Drying: The refined concentrate is fed into a belt vacuum dryer, with the vacuum level controlled at -0.08MPa. A four-stage segmented heating method is used: the first stage (feeding zone) is at 110℃ for 25 minutes to quickly remove surface free water; the second stage (core drying zone) is at 100℃ for 20 minutes to remove internal bound water; the third stage (stabilization zone) is at 90℃ for 15 minutes to regulate the particle structure; and the fourth stage (cooling zone) is at 10℃ for 20 minutes to reduce the particle temperature and remove residual trace moisture. S7. Pulverizing the finished product: The dried solid is fed into a pulverizer and initially pulverized before being passed through an 80-mesh sieve to obtain polydextrose with low viscosity and high fluidity. At this point, the angle of repose of the dried powder is 29.8°.

[0033] Example 3: S1. Material Preparation 1) Using starch milk as raw material, the pH was adjusted to 5.4, and 400 mL / T.DS β-amylase was added. The mixture was reacted in a 60℃ water bath for 8 hours. Then, 1 L / T.DS pullulanase was added to continue the reaction. The reaction was completed after 24 hours to obtain the saccharified solution. The changes in the composition of the saccharified solution were detected. The contents were: glucose 10 wt%, maltose 40%, maltotriose 40 wt%, and tetrasaccharides or higher 10 wt%. S2. Polymerization reaction 1) Add 1 wt% citric acid and 1 wt% sorbitol to the S1 saccharification solution and carry out the polymerization reaction at 160℃ and -0.1 MPa. After 20 min of reaction, the glucose content is measured to be <2 wt%. 2) Add glucose to the reaction system in 1) at a rate of 19 wt% of the previous amount. Continue the reaction at 160℃ and -0.1 MPa for 25 min. Then, check that the glucose content is <2 wt%. 3) Add 25 wt% glucose to the reaction system in 2), and continue the reaction at 160℃ and -0.1 MPa for 32 min. The glucose content is then measured to be <2 wt%. S3. Dissolution and Filtration: After the polymerization reaction is completed, add alkaline water with pH 8 to dissolve and reduce pigment formation. Then, at 50°C, pass the material through the granular activated carbon column at a flow rate of 3 times the carbon column volume / hour. The output index is ≥99% light transmittance.

[0034] S4. Ion Exchange Desalination: The cation column, containing strong acid cation resin, weak base anion resin, and strong base anion resin respectively, are regenerated using conventional methods. Then, the decolorized and filtered syrup is passed sequentially through the cation column, anion column, and anion column at a flow rate of 3 times the resin volume / hour at 40°C for ion exchange desalination.

[0035] S5. The liquid after column chromatography is concentrated to a concentration of 72wt% using a four-effect falling film evaporator at a vacuum of -0.09MPa and a liquid temperature of 85℃. At this point, the viscosity is 724 mPa·s (25℃, 70wt% solids).

[0036] S6. Drying: The refined concentrate is fed into a belt vacuum dryer, with the vacuum level controlled at -0.09MPa. A four-stage segmented heating method is used: the first stage (feeding zone) is at 120℃ for 20 minutes to quickly remove surface free water; the second stage (core drying zone) is at 110℃ for 15 minutes to remove internal bound water; the third stage (stabilization zone) is at 100℃ for 10 minutes to regulate the particle structure; and the fourth stage (cooling zone) is at 20℃ for 15 minutes to reduce the particle temperature and remove residual trace moisture. S7. Pulverizing the finished product: The dried solid is fed into a pulverizer and initially pulverized before being passed through an 80-mesh sieve to obtain polydextrose with low viscosity and high flowability. At this point, the angle of repose of the dried powder is 28.5°.

[0037] Comparative Example 1 The comparative example was prepared using the same method as Example 1, except that only one polymerization reaction was performed: 40 wt% glucose, 1 wt% citric acid, and 1 wt% sorbitol were directly added to the raw materials, and the reaction was carried out at 160°C and -0.1 MPa for 85 min; at this time, the viscosity was 940 mPa·s (25°C, 70 wt% solids), and the angle of repose of the powder after drying was 35°.

[0038] Comparative Example 2 The conventional method for preparing polydextrose involves using glucose as a raw material for polymerization; at this point, the viscosity is 1250 mPa·s (25℃, 70wt% solids), and the angle of repose of the dried powder is 35°.

[0039] According to this invention, the raw materials and reaction are controlled in a directional manner, and the reaction process is precisely regulated. By optimizing the amount of glucose added and the reaction time, the polymerization reaction is controlled to generate polydextrose with low viscosity and good flowability.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing low-viscosity polydextrose, characterized in that, Includes the following steps: The saccharified liquid was subjected to a multi-stage polymerization reaction and then purified to obtain low-viscosity polydextrose. The saccharification solution is composed of: 10 wt% glucose, 40 wt% maltose, 40 wt% maltotriose, and 10 wt% tetrasaccharides and above. The multi-stage polymerization reaction specifically refers to: (1) Add 1wt% citric acid and 1wt% sorbitol to the saccharification solution and react under high temperature conditions until the glucose content is <2wt% to complete the first stage of polymerization reaction; (2) Add glucose to the reaction system of step (1) in an amount of 10-30 wt% of the previous system, and continue the reaction until the glucose content is <2 wt%, thus completing the second stage of polymerization reaction; (3) Add 20-40 wt% glucose to the reaction system in step (2) and continue the reaction until the glucose content is <2 wt%.

2. The preparation method according to claim 1, characterized in that, The saccharified solution is obtained by enzymatic hydrolysis of starch. The specific method is as follows: using starch milk as raw material, adjusting the pH to 5.1-5.4, adding 400 mL / T.DS of β-amylase and reacting in a 60℃ water bath for 8 hours, then adding 1 L / T.DS of pullulanase and continuing the reaction for 24 hours before stopping the reaction.

3. The preparation method according to claim 1, characterized in that, The reaction conditions in step (1) are as follows: Reaction temperature: 160℃; Reaction pressure: -0.1 MPa; Reaction time: 10-40 min.

4. The preparation method according to claim 1, characterized in that, The reaction conditions in step (2) are as follows: Reaction temperature: 160℃; Reaction pressure: -0.1 MPa; Reaction time: 20-40 min.

5. The preparation method according to claim 1, characterized in that, The reaction conditions in step (3) are as follows: Reaction temperature: 160℃; Reaction pressure: -0.1 MPa; Reaction time: 30-40 min.

6. The preparation method according to claim 1, characterized in that, The purification method is as follows: after the polymerization reaction is completed, add alkaline water with pH 7-9 to dissolve the product, and then perform ion exchange desalting, concentration, and drying.

7. The preparation method according to claim 6, characterized in that, The resins used for ion exchange desalination are, in order, a strong acid cation resin, a weak base anion resin, and a strong base ion resin.

8. The preparation method according to claim 6, characterized in that, The viscosity of the polydextrose at 25°C is 600-800 mPa·s.