Determination of key aroma components of Cheddar cheese using dynamic headspace dilution assay

Gas chromatography-olfactometry (GCO) and a dilution assay, dynamic headspace dilution assay (DHDA), were used to determine the most potent aroma compounds in mild Cheddar cheese. Sample dilution was performed by a stepwise decrease of the purge time (starting at 30 min = FD1 to a final purge time of 20 s = FD 64) using a constant purge flow of 50 ml/min. Each dilution was sniffed three times and the odorous compounds were marked on the GC chromatogram. The identification of the odorants was based of their mass spectra, retention times on at least two different columns and odour character at the sniffing port. This method has found the highest FD-factors for 2,3-butandione, (Z)-4-heptenal, methional, 2-acetyl-1-pyrroline, dimethyl trisulphide, 1-octen-3-one, (Z)-1,5-octadien-3-one, furaneol, (Z)-2-nonenal and (E)-2-nonenal, suggesting that these are the most potent odorants in Cheddar cheese. Three additional compounds remain unknown.