Sensory and mass spectrometric analysis of the peptidic fraction lower than one thousand daltons in manchego cheese

A total of 107 different peptides, all derived from alpha(S1)-, alpha(S2)-, and beta-casein, were identified in different fractions of artisan or industrial Manchego cheese at 4 and 8 mo of ripening, and their sequences were examined. Most of these peptides are described for the first time in Manchego cheese. Taste characteristics (umami and bitter) were assigned based on their AA sequence and the position of these AA within the sequence. The umami taste was predominant in all fractions analyzed by the panelists, and the peptides EQEEL, QEEL, and EINEL, containing a high number of glutamic residues, were found within the fractions. However, in several fractions described as having umami characteristics, no peptides responsible for this taste were detected. Therefore, compounds other than peptides seem to be involved in the umami properties of water-soluble extracts lower than 1,000 Da of Manchego cheese.