Polypeptide preparation method

The invention discloses a polypeptide preparation method. The method comprises the following steps: A, firstly, removing fish meat of grass carp to obtain grass carp bones; b, pretreating the grass carp bones; c, immersing the pretreated bones in an ethanol solution, and performing ultrasonic treatment to obtain treated grass carp bones; d, adding the grass carp bones into a crusher, and crushing for multiple times to obtain grass carp bone meal; e, preparing grass carp bone slurry from the grass carp bone meal; f, quickly freezing the grass carp bone slurry in a freezer to obtain frozen blocks; g, taking out the frozen blocks, soaking the frozen blocks in oxygen-free water, and carrying out ice melting treatment to obtain a grass carp bone solution; h, adding a composite biological enzyme into the grass carp bone solution to carry out primary enzymolysis treatment; i, adding purified water into the primary enzymatic hydrolysate, and treating the mixed solution in a vacuum impregnation kettle; j, carrying out