The invention provides a method for efficiently preparing
starch nanocrystalline, and belongs to the field of
starch processing. The method combines the techniques of
waxy starch debranching to prepare straight-chain
dextrin, the molecular
weight distribution of straight-chain
dextrin is narrowed through classification, self-
assembly of straight-chain
dextrin is accelerated by combining
polyethylene glycol
precipitation to form
starch nanocrystalline, and the starch nanocrystalline is prepared. The method mainly comprises the steps that
waxy starch is dextrinized,
pullulanase is debranched toobtain a straight-chain dextrin solution, ethyl
alcohol is added while stirring is conducted till the volume ratio of the straight-chain dextrin solution to ethyl
alcohol is 3 to 1, the mixed solutionis continuously stirred for 10 min and standing for 1 h at the temperature of 4 DEG C,
centrifugation is conducted, and the
sediment is removed; ethyl
alcohol is slowly added continuously in the supernatant liquid till the volume ratio of straight-chain dextrin to ethyl alcohol is 1 to 3, stirring is conducted continuously for 10 min, the obtained product is standing for 1 h at the temperature of4 DEG C,
centrifugation is conducted, and straight-chain dextrin
sediment is obtained; straight-chain dextrin is dispersed in water, the straight-chain dextrin solution with the concentration being 4.0-8.0% is prepared,
polyethylene glycol is added in the straight-chain dextrin solution at the proportion of 40.0-50.0 g to 100 mL, the mixture is heated and stirred till
polyethylene glycol is completely dissolved, the product is cooled to be 4 DEG C and standing for 1-2 h at the temperature of 4 DEG C,
centrifugation is conducted to obtain the
sediment, the residual
polyethylene glycol is washed through trichloromethane, the product is blasted and dried for 5 min at the temperature of 40 DEG C, and the starch nanocrystalline is obtained.