Lactococcus lactisstrain AMP2I expresses OppA(D471R), a mutant oligopeptide binding OppA protein in which the aspartyl residue at position 471 was replaced by arginine. As a consequence of a different peptide transport in this strain, experimental Hispánico cheese made withLc. lactisAMP2I had a higher content of total free amino acids than control cheese made withLc. lactisAMP1I, an isogenic strain expressing wild-type OppA (Picon et al. 2005, 2007). In this work higher levels of diketones, hydroxy-ketones and, to a lesser extent, branched chain aldehydes were recorded for experimental cheese compared with control cheese. These differences levelled off as ripening proceeded. Strong correlations support the hypothesis that the increased levels of these volatile compounds in cheese made withLc. lactisAMP2I are linked to higher concentrations of free amino acids threonine, valine and leucine.