Pregelatinized starch production process

Pregelatinized starch production process

Pregelatinized starch is a kind of modified starch with simple processing and wide use, which is prepared by using physical, chemical or enzymatic methods to rapidly heat the starch granules while they are still in suspension to make the starch gelatinized or partially gelatinized, and then prepared by cooling, aging, drying and other processes. There are many production processes for pregelatinized starch, among which acidolysis is the most widely used.

The production process of pregelatinized starch by acidolysis includes raw material selection, soaking, acidolysis, neutralization, bleaching, dehydration, drying and other steps. The key points and precautions for each step are detailed below.

First, the selection of raw materials.

Choose raw materials with high starch content and few impurities, such as potato starch, corn starch, etc. These raw materials are abundant, relatively low, and high in starch, which is beneficial for improving the quality and yield of the product.

2. Soaking. Soak the selected raw materials in water, and the general soaking time is 2-4 hours. The purpose of soaking is to make the starch granules fully absorb water and expand, which is conducive to the subsequent acidolysis operation. At the same time, the water should be kept clean during the soaking process to avoid the breeding of miscellaneous bacteria.

3. Acidolysis. The soaked starch slurry is heated to 40-50, an appropriate amount of hydrochloric acid is added, and the pH value is adjusted to 2-3, so that the starch granules begin to hydrolyze under acidic conditions. During the acidolysis process, it is necessary to stir continuously to make the starch granules fully contact the acid, and at the same time, pay attention to controlling the temperature and pH value to avoid excessive or insufficient acidolysis.

Fourth, neutralization. After the acidolysis is completed, the pH value is adjusted to 6-7 with sodium hydroxide solution to make the starch granules neutral. When neutralizing, the lye should be added slowly, and stirred constantly to make the starch granules evenly contact with the lye. At the same time, it is necessary to pay attention to controlling the range of pH value to avoid gelatinization or incomplete hydrolysis of starch granules due to too high or too low pH value.

5. Bleaching. In order to make the product more white and transparent, it needs to be bleached. Sodium hypochlorite is usually used as a bleaching agent, and an appropriate amount of stabilizer is added to improve the bleaching effect. During bleaching, the amount and reaction time of sodium hypochlorite should be controlled to avoid affecting the quality of the product.

6. Dehydration. The bleached starch slurry is dehydrated to reduce the moisture content to the specified range. There are various methods of dehydration, such as natural drying, mechanical dehydration, etc. When dehydrating, the temperature and humidity should be controlled to avoid cracks or agglomeration of starch granules.

7. Drying. The dehydrated starch block is dried so that the moisture content in the starch is reduced to the specified range. Drying methods include natural drying and hot air drying. When drying, the temperature and humidity should be controlled to avoid discoloration or odor of starch granules.

Through the above seven steps, the production process of pregelatinized starch can be obtained. In the production process, the process parameters should be strictly controlled to ensure that the product quality meets the standard requirements. At the same time, it is necessary to pay attention to safe production and environmental protection to avoid adverse effects on workers' health and the environment.