Amino acid：Amino acid is the generic name of a group organic substance containing amino group and carboxyl group. It is the fundamental material to construct bio-organism proteins, and correlates with living activities closely. In human body, it has special physiological functions, and it is one of the essential nutrients in bio-organisms.
functional peptide ：Peptide is a substance between amino acid and protein, a compound linked by two or two more amino acids with the use of peptide linkages. It is a brand new nutrient with highest activities and valuable physiological functions, and the active substance in bio-organisms.
protein：Protein is a biomacromolecule composed of a single or several polypeptide strains, and it is the basic material to build up life. There will be no life if no protein is available, and protein is a group of protein closely correlated with life, and various living activities.