Method for preparing resistant dextrin

A method for preparing resistant dextrin, comprising the following steps:

• 1) Mixing a starch with water, and removing a protein to obtain a starch milk, the mixture obtained after mixing the starch and the water in the step 1) has a starch milk baume degree of 20° Bé to 30° Bé, the protein removal rate in the step 1) is ≥98%;
• 2) mixing the starch milk obtained in the step 1) with an acid to perform hydrolysis reaction and obtain a hydrolysis reaction solution, in which the acid is at least one selected from the group consisting of hydrochloric acid, phosphoric acid, citric acid, and malic acid;
• the acid is added in the form of an acid solution;
• the acid solution has a concentration of 1 wt % to 2 wt %;
• the acid solution is added at a mass amount of 1% % to 3% % relative to the starch mass;
• and a temperature of the hydrolysis reaction is 85° C. to 95° C. and a time of the hydrolysis reaction is 30 min to 90 min;
• 3) allowing the hydrolysis reaction solution obtained in the step 2) to undergo evaporation concentration and polymerization reaction in turn to obtain a crude resistant dextrin;
• and
• 4) Refining the crude resistant dextrin obtained in the step 3) to obtain the resistant dextrin.