阅读说明：本技术 一种淀粉-三偏磷酸钠交联的反向控制方法及其应用 (Reverse control method for starch-sodium trimetaphosphate crosslinking and application thereof ) 是由 李毅伦 *** 于 2020-08-12 设计创作，主要内容包括：本发明涉及淀粉交联改性技术领域,具体涉及一种淀粉-三偏磷酸钠交联的反向控制方法及其应用,该反向控制方法包括如下步骤：(S1)、取粘度低于规定范围的淀粉-三偏磷酸钠交联反应浆；(S2)、升高所述淀粉-三偏磷酸钠交联反应浆的反应温度和pH值,且保证所述淀粉-三偏磷酸钠交联反应浆不糊化,反应至所述淀粉-三偏磷酸钠交联反应浆的粘度上升；(S3)、继续反应至粘度落入规定范围,即实现反向控制。该反向控制方法专门针对淀粉与三偏磷酸钠交联过程中过度交联导致粘度低于规定范围的情况,使产品粘度升高并满足出厂粘度的规定范围,避免变性淀粉出厂粘度低于规定范围造成产品不合格而报废。(The invention relates to the technical field of starch crosslinking modification, in particular to a reverse control method for starch-sodium trimetaphosphate crosslinking and application thereof, wherein the reverse control method comprises the following steps: (S1) taking starch-sodium trimetaphosphate crosslinking reaction slurry with the viscosity lower than the specified range; (S2) raising the reaction temperature and the pH value of the starch-sodium trimetaphosphate crosslinking reaction slurry, ensuring that the starch-sodium trimetaphosphate crosslinking reaction slurry is not gelatinized, and reacting until the viscosity of the starch-sodium trimetaphosphate crosslinking reaction slurry is raised; (S3), and continuing to react until the viscosity falls in the specified range, namely realizing reverse control. The reverse control method is specially used for solving the problem that the viscosity is lower than the specified range due to excessive crosslinking in the crosslinking process of the starch and the sodium trimetaphosphate, so that the viscosity of the product is increased and the specified range of the factory viscosity is met, and the condition that the product is unqualified and scrapped due to the fact that the factory viscosity of the modified starch is lower than the specified range is avoided.)

1. A reverse control method for starch-sodium trimetaphosphate crosslinking is characterized by comprising the following steps:

(S1) taking starch-sodium trimetaphosphate crosslinking reaction slurry with the viscosity lower than the specified range;

(S2) raising the reaction temperature and the pH value of the starch-sodium trimetaphosphate crosslinking reaction slurry, ensuring that the starch-sodium trimetaphosphate crosslinking reaction slurry is not gelatinized, and reacting until the viscosity of the starch-sodium trimetaphosphate crosslinking reaction slurry is raised;

(S3), continuing the reaction until the viscosity of the starch-sodium trimetaphosphate crosslinking reaction slurry falls into a specified range, namely realizing reverse control of the starch-sodium trimetaphosphate crosslinking.

2. The method of claim 1, wherein the reverse control of the cross-linking of starch-sodium trimetaphosphate is as follows: the reaction temperature is controlled at 35-45 ℃.

3. The method of claim 1, wherein the reverse control of the cross-linking of starch-sodium trimetaphosphate is as follows: the pH value is controlled to be 10.5-11.2.

4. The method of claim 1, wherein the reverse control of the cross-linking of starch-sodium trimetaphosphate is as follows: in the step (S1), the starch-sodium trimetaphosphate crosslinking reaction slurry is obtained from a reaction slurry in a process of producing modified starch by crosslinking and modifying starch and sodium trimetaphosphate.

5. The method of claim 4, wherein the reverse control of the cross-linking of starch-sodium trimetaphosphate is as follows: the weight ratio of the starch to the sodium trimetaphosphate is 1: 0.014-0.050.

6. The method of claim 1, wherein the reverse control of the cross-linking of starch-sodium trimetaphosphate is as follows: in the step (S2), the reaction time is 18-28 h.

7. Use of a method of reverse control of the cross-linking of starch-sodium trimetaphosphate according to any one of claims 1 to 6, wherein: the reverse control method of starch-sodium trimetaphosphate crosslinking is used for increasing the viscosity of excessively crosslinked modified starch.

Technical Field

The invention relates to the technical field of starch crosslinking modification, in particular to a reverse control method of starch-sodium trimetaphosphate crosslinking and application thereof.

Background

In the production process of modified starch, a common modification mode is crosslinking modification. The cross-linking bond is formed between starch molecules, so that the average molecular mass of the starch is improved, the intermolecular connection strength is enhanced, the starch granule structure is stronger, and the stability of the starch paste is improved.

Any chemical reagent having two or more functional groups that react with two or more hydroxyl groups in the starch molecule can be used as a crosslinking agent. Sodium trimetaphosphate is a commonly used cross-linking agent and has mild properties. However, the method has the problems that the sodium trimetaphosphate can hardly be stopped in the crosslinking reaction process, the viscosity of the product is continuously reduced, excessive crosslinking is easy to occur in the production process, the leaving viscosity of the modified starch is lower than the specified range, and the product is unqualified and discarded.

Disclosure of Invention

In order to overcome the defects and shortcomings in the prior art, the invention aims to provide a reverse control method for starch-sodium trimetaphosphate crosslinking, which is specially used for solving the problem that the viscosity is lower than a specified range due to excessive crosslinking in the crosslinking process of starch and sodium trimetaphosphate, and realizes reverse control (the reverse control is defined as de-crosslinking) on the crosslinking of the starch and the sodium trimetaphosphate after a product with the viscosity lower than the specified range continuously reacts by controlling conditions such as reaction temperature, pH value and the like, so that the viscosity of the product is increased and meets the specified range of factory viscosity, and the product is prevented from being rejected due to disqualification caused by the fact that the factory viscosity of modified starch is lower than the specified range; the reverse control method is simple to operate, convenient to control, high in production efficiency and low in production cost, and can be used for large-scale reverse control production.

Another object of the present invention is to provide an application of a reverse control method of starch-sodium trimetaphosphate crosslinking for increasing the viscosity of excessively crosslinked modified starch.

The purpose of the invention is realized by the following technical scheme: a reverse control method for starch-sodium trimetaphosphate crosslinking comprises the following steps:

(S1) taking starch-sodium trimetaphosphate crosslinking reaction slurry with the viscosity lower than the specified range;

(S2) raising the reaction temperature and the pH value of the starch-sodium trimetaphosphate crosslinking reaction slurry, ensuring that the starch-sodium trimetaphosphate crosslinking reaction slurry is not gelatinized, and reacting until the viscosity of the starch-sodium trimetaphosphate crosslinking reaction slurry is raised;

(S3), continuing the reaction until the viscosity of the starch-sodium trimetaphosphate crosslinking reaction slurry falls into a specified range, namely realizing reverse control of the starch-sodium trimetaphosphate crosslinking.

The reverse control method of the starch-sodium trimetaphosphate crosslinking is specially used for solving the problem that the viscosity is lower than a specified range due to excessive crosslinking in the starch and sodium trimetaphosphate crosslinking process, and the solution crosslinking is realized according to the scheme. Meanwhile, the reverse control method is not suitable for the existing lightly crosslinked product and the existing product after etherification and esterification processes are carried out in the crosslinking process. Wherein, in the step (S2), the reaction temperature and the pH value are increased to accelerate the size decomposition and crosslinking speed of the starch-sodium trimetaphosphate crosslinking reaction; the starch-sodium trimetaphosphate crosslinking reaction slurry is guaranteed not to be pasted, and the product scrapping caused by uncontrollable reaction due to repeated crosslinking in the crosslinking releasing process is avoided.

Preferably, the reaction temperature is controlled to be 35-45 ℃.

By adopting the technical scheme, gelatinization of the starch-sodium trimetaphosphate crosslinking reaction slurry in the temperature rise process is avoided.

Preferably, the pH value is controlled to be 10.5-11.2.

By adopting the technical scheme, gelatinization of the starch-sodium trimetaphosphate crosslinking reaction slurry in the process of increasing the pH value is avoided.

Preferably, in the step (S1), the starch-sodium trimetaphosphate crosslinking reaction slurry is obtained from a reaction slurry in a process of producing modified starch by crosslinking and modifying starch and sodium trimetaphosphate.

By adopting the technical scheme, the viscosity of the product is increased and the specified range of the factory viscosity is met by adopting the reverse control method of starch-sodium trimetaphosphate crosslinking, and the unqualified product and the scrapping caused by the fact that the factory viscosity of the modified starch is lower than the specified range are avoided.

Preferably, the weight ratio of the starch to the sodium trimetaphosphate is 1: 0.014-0.050.

By adopting the technical scheme, the adding proportion of sodium trimetaphosphate in the reaction process is strictly regulated from the actual production, and under the condition of excessive crosslinking in the reaction process, the reaction time is prolonged, the reaction temperature, the pH value and other conditions are increased, and the reverse control of the crosslinking of the starch-sodium trimetaphosphate is realized. In practice, if the amount of sodium trimetaphosphate used is too low, the weight ratio of starch to sodium trimetaphosphate is less than 1: 0.014, after the reaction according to the reverse control method of the starch-sodium trimetaphosphate crosslinking of the invention, the viscosity of the starch-sodium trimetaphosphate crosslinking reaction slurry is continuously stable in a small range, and the decrosslinking cannot be realized.

Preferably, in the step (S2), the reaction time is 18 to 28 hours.

By adopting the technical scheme, the reaction time is 18-28h, the sampling is carried out once in the area at intervals of 1h to measure the viscosity rise of the starch-sodium trimetaphosphate crosslinking reaction slurry, the phenomenon that excessive sampling increases the loss of manpower and materials is avoided, the observation, estimation and control of the degree of crosslinking release are convenient, the crosslinking release is stopped when the viscosity of the product rises and meets the specified range of the factory viscosity, and the uncontrollable production process caused by excessive crosslinking release and repeated crosslinking is avoided.

The other purpose of the invention is realized by the following technical scheme: the application of the reverse control method of the starch-sodium trimetaphosphate crosslinking is used for increasing the viscosity of the excessively crosslinked modified starch.

The invention has the beneficial effects that: the reverse control method of starch-sodium trimetaphosphate crosslinking is specially used for the situation that the viscosity is lower than the specified range due to excessive crosslinking in the crosslinking process of starch and sodium trimetaphosphate, so that a product with the viscosity lower than the specified range continuously reacts under the conditions of controlling the reaction temperature, the pH value and the like, and the reverse control (the reverse control is defined as de-crosslinking) of the crosslinking of the starch and the sodium trimetaphosphate is realized, so that the viscosity of the product is increased and the specified range of the factory viscosity is met, and the condition that the factory viscosity of the modified starch is lower than the specified range, so that the product is unqualified and scrapped; the reverse control method is simple to operate, convenient to control, high in production efficiency and low in production cost, and can be used for large-scale reverse control production.

The invention relates to application of a reverse control method of starch-sodium trimetaphosphate crosslinking, which is used for increasing the viscosity of excessively crosslinked modified starch.

Drawings

FIG. 1 is a graph of the viscosity of starch as a function of reaction time for example 5 of the present invention;

FIG. 2 is a graph of the viscosity of starch as a function of reaction time for example 6 of the present invention;

FIG. 3 is a graph of the viscosity of the starch of comparative example 2 of the present invention as a function of the reaction time.

Detailed Description

For the understanding of those skilled in the art, the present invention will be further described with reference to the following examples and drawings, which are not intended to limit the present invention.