The oligopeptides of sweet and acid cheese whey

The 12% TCA-soluble oligopeptide fraction of sweet whey from Provolone and Grana Padano cheese, and of acid whey from Quarg cheese was fractionated by HPLC and the peptide components identified using a combination of mass spectrometry and Edman degradation. In the sweet whey, in addition to the two differently phosphorylated forms of caseinomacropeptide (CMP), the peptides β-CN(1-29), β-CN(1-28), α-CN(f1-22), and α-CN(f1-23) were found. The chymosin-derived α-CN peptides were absent from the Quarg cheese whey, whereas shortened forms occurred as a consequence of the degradation by starter proteinases. In Quarg cheese whey, 50 peptides were from β-CN, 34 from κ-CN, seven from α-CN and none from α-CN. Some peptides known to be released during the in vitro action of P-and P-type proteinases on single casein fractions occurred also in Quarg cheese whey.