The invention discloses a method for preparing
starch nanocrystal, and belongs to the field of
modified starch processing. The method is based on the principle that lipid
layers in waxiness
corn starch grains have resistance for acid, the
starch is prompted to be crushed because of homogenization treatment under a certain pressure, the lipid is prompted to be digested through Soxhlet extraction by using an
alcohol-water solution, a pore structure from outside to inside is formed, then the resistance to the acid is eliminated, and the penetration of the acid inside the
starch is prompted under a negative pressure condition so as to accelerate
hydrolysis of the starch grains in an amorphous area. The method specifically comprises the following steps: homogenously crushing the starch grains under a pressure of 50-150 MPa,
degreasing the crushed starch by using a 70-90%
methanol-water solution, and accelerating
hydrogen ions in
sulfuric acid to rapidly penetrate into the starch grains to be subjected to restrictive
hydrolysis under a 0.06-0.1MPa negative pressure condition, so as to prepare the
nanocrystal. Through the technical measures, the
hydrolysis period of the starch is shortened to be 48-72 hours, the starch
nanocrystal yield is greatly improved to be 19-25%, and the
particle size distribution is 20-300nm.