Preparation method for wheat bran dietary fiber

The invention relates to a preparation method for wheat bran dietary fiber. The preparation method comprises the following steps: (1) crushing the wheat bran, soaking the crushed wheat bran and defibrinating; (2) adjusting the pH value of a material to be 7.5-9.0 and adding alkaline protease into the material and reacting for 2.0-3.0 hours; (3) heating the material to 65-75 DEG C, adding mesophilic alpha-diastase and reacting for 30-80 minutes; (4) cooling the material to 45-55 DEG C, adding phytase and reacting for 2.0-3.0 hours; and (5) carrying out suction filtration in vacuum on the material and drying, puffing, roasting and crushing the residues after suction filtration to obtain the wheat bran dietary fiber. The obtained wheat bran dietary fiber product not only is low in content of phytic acid, but also has relatively strong water absorption capability. Other components in the bran are further fully utilized. The used reagents are free of toxicity and harm, so that the problem of environmental pollution is avoided, and moreover, the economical benefit of the product is improved.