Different chemical indices related to proteolysis and ripening time have been investigated in Grana Padano (n = 155) and Parmigiano-Reggiano (n = 27) cheese samples using ion-exchange chromatography and capillary electrophoresis. Levels of intact caseins, g-casein and free amino acids in cheese were not strictly related to the maturation period, varying among samples of the same age. A peptide, identified by HPLC/electrospray ionization-mass spectrometry as pyroglutamyl-g3-casein, resulted from cyclisation of N-terminal glutamic acid into a pyroglutamic acid residue. Based on the peak area ratio of pyroglutamyl-g3-casein and g3-casein, an equation, suitable for determination of the cheese age, is proposed. The commercial classes of Grana Padano ripened over 16 and 20 months can be identified by adopting a minimum threshold value for this peak area ratio.
Proteolysis indices related to cheese ripening and typicalness in PDO Grana Padano cheese / F. MASOTTI, J.A.L.A. HOGENBOOM, V. ROSI, I. DE NONI, L.M. PELLEGRINO. - In: INTERNATIONAL DAIRY JOURNAL. - ISSN 0958-6946. - 20:5(2010 May), pp. 352-359.
Proteolysis indices related to cheese ripening and typicalness in PDO Grana Padano cheese
F. MASOTTIPrimo
;J.A.L.A. HOGENBOOMSecondo
;V. ROSI;I. DE NONIPenultimo
;L.M. PELLEGRINOUltimo
2010
Abstract
Different chemical indices related to proteolysis and ripening time have been investigated in Grana Padano (n = 155) and Parmigiano-Reggiano (n = 27) cheese samples using ion-exchange chromatography and capillary electrophoresis. Levels of intact caseins, g-casein and free amino acids in cheese were not strictly related to the maturation period, varying among samples of the same age. A peptide, identified by HPLC/electrospray ionization-mass spectrometry as pyroglutamyl-g3-casein, resulted from cyclisation of N-terminal glutamic acid into a pyroglutamic acid residue. Based on the peak area ratio of pyroglutamyl-g3-casein and g3-casein, an equation, suitable for determination of the cheese age, is proposed. The commercial classes of Grana Padano ripened over 16 and 20 months can be identified by adopting a minimum threshold value for this peak area ratio.Pubblicazioni consigliate
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