Resistant dextrin and method for preparing the same

A method for preparing a resistant dextrin comprises the following steps:

• (1) adding hydrochloric acid solution into starch according to mass percent of 0.3% and uniformly stirring the mixture to obtain a reaction material;
• (2) increasing temperature of the reaction material obtained in step (1) to 100° C., performing reaction for 3 h at normal pressure to obtain an initial reaction material, then adding hydrochloric acid solution according to mass percent of 6% relative to the initial reaction material, uniformly stirring the mixture, increasing temperature to 160° C. and performing gelatinization reaction for 22 min at normal pressure to obtain a dextrin crude material;
• (3) adding deionized water into the dextrin crude material obtained in step (2), regulating sugar concentration to 43 wt %, and preserving heat to perform acidic hydrolysis for 1.5 h at 91° C. to obtain hydrolysate;
• and
• (4) adding activated carbon into the hydrolysate obtained in step (3) according to dry-base mass percent of 1.0%, preserving heat and stirring for 30 min, and then performing filtration to obtain feed liquid with light transmittance of 96%;
• then regulating temperature of feed liquid before entering a column to 45° C. and pH of feed liquid exiting the column to 4.5 to obtain ion exchange liquid with electric conductivity smaller than 100 μs/cm and light transmittance greater than or equal to 98%;
• then performing sextuple-effect concentration to solid substance mass content of 55%;
• and
• performing chromatographic purification, secondary discoloration, secondary ion exchange, secondary concentration and belt vacuum drying to water mass content of 5% to obtain the resistant dextrin;
• wherein the hydrochloric acid solution in step (1) and step (2) have a mass concentration of 0.12%.