The invention discloses a method for preparing a corn
peptide by using corn
gluten water. The method comprises the steps: regulating the pH value of the corn
gluten water to 5.5-8.0 by using
sodium sulfite, then, carrying out ultrasonic treatment, and centrifugally collecting a liquid; regulating the pH value of the liquid to 8-11 by using
sodium hydroxide, and adding
alkaline protease to carry out enzymolysis; and removing impurities in an enzymatic
hydrolysate through a
microfiltration membrane, then, concentrating the
microfiltration filtrate through a
nanofiltration membrane, and carrying out
drying treatment on a concentrate to obtain the corn
peptide. The method is used for producing the corn
peptide through extracting by taking the corn
gluten water as the
raw material, so that the production cost is relatively low; through
pH regulation and ultrasonic treatment,
prolamin is modified before enzymolysis is finished, so that the purity of a
protein and the
hydrolysis effect are improved; through two-stage membrane separation treatment, a corn peptide product containing 90% of proteins is obtained, and the process yield is about 85%; extraction is realized without using an
organic solvent, and the corn peptide product is free of
solvent residues and high in safety; the COD (
Chemical Oxygen Demand) of a small deal of residual
wastewater is less than or equal to 800mg / L, and the
wastewater can be discharged up to the standard after being treated a little.