Count (A) and abundance (B) of peptides derived from milk proteins and identified in human breast milk. Results are shown as means ± SD, n = 8. CASB, β-casein; OSTP, osteopontin; CASA1, αs1-casein; BT1A1, butyrophilin subfamily 1 member A1; PIGR, polymeric immunoglobulin receptor; CEL, bile salt-activated lipase; PLIN2, perilipin-2; MUC1, mucin-1; FIBA, fibrinogen α-chain; CASK, κ-casein; TRFL, lactoferrin