Study of the oligopeptide fraction in Grana Padano and Parmigiano-Reggiano cheeses by liquid chromatography electrospray ionization mass spectrometry.

摘要: The oligopeptide fractions of Grana Padano and Parmigiano Reggiano cheese samples, at various stages ageing (6, 12, 18 24 months), were analysed by means high-performance liquid chromatography coupled to electrospray ionisation mass spectrometry (ESI-MS). main oligopeptides (< 5000 Da) present in the samples extracted using an originally developed method which allowed good enrichment identified according their molecular weights. casein sequences compatible with found weights determined exact fragmentation peaks originated in-source collisionally-induced dissociation (CID). ESI-MS reported here sequence identification very quickly a single chromatography-mass run. Oligopeptides also semi-quantified comparison suitable internal standard (the dipeptide phenylalanyl-phenylalanine, Phe-Phe). This methodology demonstrated that, as far are concerned, presented similar composition. Anyway, evolution during time was characteristically distinct among two cheeses: cheeses most reached maximum 12 months then decreased, whereas amounts usually lower had less regular trend. reason for this different behaviour may be ascribed production techniques.