Method for enzymatically preparing peptides for use in improvement of brain function

A method for preparing a peptide for improving brain function, comprising:

• hydrolyzing milk casein with an enzymatic catalyst comprising a protease from a microorganism belonging to either the genus Bacillus or the genus Aspergillus, but not both, to produce a hydrolysate comprising:
• (i) a peptide consisting of the amino acid sequence shown in SEQ ID NO:
• 1;
• (ii) a peptide consisting of the amino acid sequence shown in SEQ ID NO:
• 2;
• or
• (iii) a mixture of the peptides of (i) and (ii),
• wherein
• the protease is selected from the group consisting of Protin SD-AY10, Sumizyme MP, Sumizyme LP50, Protease P5459, Protease P “amano” 3SD, Sumizyme FP, Proteax, and Umamizyme G;
• and isolating the peptide consisting of the amino acid sequence shown in SEQ ID NO:
• 1, the peptide consisting of the amino acid sequence shown in SEQ ID NO:
• 2, or a mixture comprising the peptides.