Preparation method of phosphate rice starch

Abstract

The preparation method of phosphate rice starch includes the following steps: (1) starch, sodium dihydrogen phosphate equivalent to 5wt%-1wt% of dry starch and urea equivalent to 2wt%-6wt% of dry starch are mixed and agitated. And then water is added to make the mixture into slurry. The water content of the slurry is 5wt%-12wt%. Under agitation, NaOH solution is added to adjust pH value to 5.5-6.5, and the temperature is controlled at 40 DEG C-60 DEG C. After the mixture is agitated 20-40min, it will be filtered; (2) at a 40-50 DEG C drying oven, the filter cake is preliminarily dried till water content is 5wt%-10wt%; (3) the reaction temperature is adjusted to 120 DEG C-150 DEG C. After reaction lasts 1-4h, the material will be cooled and mixed into finished product. With less phosphate,the present invention may prepare rice starch product with high substitution degree, high viscosity, transparent paste, good aging resistance, desirable water holding capacity, high stability and small environmental pollution.

Description

technical field [0001] The invention relates to a method for preparing modified starch, in particular to a method for preparing phosphate rice starch with different degrees of substitution by using rice as a raw material. Background technique [0002] The main component of rice is starch (accounting for more than 80%). Restricted by many factors such as raw materials, cost and people's consumption level, rice starch and its derivatives started late and developed slowly, and their proportion in the industry of starch and its derivatives is very small. At present, among starch products, the output of rice starch ranks fourth in the world after corn, wheat and potato starch. Compared with other grain starch granules, rice starch granules are very small (3-5 microns), and other grains such as corn, wheat and other starch granules are mostly more than 15 microns. Therefore, rice starch and its derivatives have their unique characteristics in many fields. use. [0003] However,...

AI Technical Summary

Problems solved by technology

Monoester phosphate starch mainly uses orthophosphate and sodium tripolyphosphate (STP) as phosphorylating agent. The biggest disadvantage of STP is that it is easy to cross-link with starch, reduce the viscosity of starch, and the obtained starch has a relatively low degree of substitution. , generally 0.02

When orthophosphate is used to prepare phosphate starch by wet method, the biggest disadvantage is that the amount of esterification agent is large, the three wastes are much, and the environmental pollution is serious.

When the phosphate starch prepared by orthophosphate is produced by dry method, the biggest disadvantage is the high requirements for spray mixing equipment, large dust during production, easy explosion, and low product uniformity.

Diester phosphate starch is generally produced by wet method, mainly using phosphorus oxychloride and trimetaphosphate as esterification agents, starch phosphate diester is also prone to cross-linking reaction, the amount of esterification agent is large, and there are many three wastes, which is harmful to the environment. Pollution is equally serious, so it is also difficult to popularize and apply in production