The invention relates to a preparation method of reducible resistant
dextrin, which comprises the following steps: (1) adding water into
starch to regulate
starch milk; (2) regulating pH of
starch milk to add high-temperature resistant alpha;
amylase, reacting to obtain liquefied liquid; (3) adjusting pH of liquefied liquid, adding
fungus alpha-
Amylase and
pullulanase, concentrating to obtain a
mixed solution after reaction; 4) adding
phosphoric acid into that
mixed solution, reacting under the conditions of high temperature and negative pressure to obtain a resistant
dextrin crude solution; 5) adjusting the pH of the crude solution of the resistant
dextrin and adding a catalyst
Raney nickel to obtain a reaction solution aft the reaction; and 6, decoloring the reaction solution, filtering,
ion exchange, concentrating, and
drying to obtain reducible resistant dextrin. The reduced resistant dextrin prepared by the invention hardly contains small molecular
sugar such as glucose,
maltose and
trisaccharide, has lower
water activity value, better
moisture retention and bacteriostatic performance, and is favorable for improving the
shelf life of food and prolonging the
shelf life of food.