Extraction method of natural high-content selenium-source rice peptide

The invention relates to the field of selenium-source rice peptide extraction and feed additives and particularly discloses an extraction method of natural high-content selenium-source rice peptide. The extraction method comprises the following steps: weighing crushed and sieved selenium-rich rice, adding distilled water and flavourzyme, putting the mixture into an ultrasonic wave extractor, carrying out enzymolysis for 4-6 hours, wherein the weight of the distilled water is 9-12 times that of the rice, the weight of the flavourzyme is 2%-4% that of the rice, and the pH value of a reaction system is maintained to be 7-8; after the enzymolysis, heating obtained enzymatic hydrolysate to 90-100 DEG C, maintaining the temperature for 5-10 minutes, and carrying out enzyme deactivation; centrifuging the enzymatic hydrolysate, separating and purifying filtrate by virtue of a membrane separation technique, so as to obtain concentrated liquid; carrying out spray drying on the concentrated liquid, so as to obtain the high-content selenium-source rice peptide. The extraction method has the beneficial effects that no acid-base solution is added, the activity of selenium is maintained, the content of organic selenium in a product is increased, and meanwhile, the environmental pollution is avoided; the filtrate is separated and purified by virtue of the membrane separation technique, so that the process is simple and convenient, and the cost is low.