Characterisation of volatile flavour compounds in Roncal cheese extracted by the ‘purge and trapʹ method and analysed by GC–MS

The objective of this study was to identify the volatile compounds characteristic of Roncal Protected Denomination of Origin (AOC) cheese. Samples were taken from all the cheese makers registered with the Roncal AOC and were compared in the different periods of lactation. The equipment used was a ‘purge and trapʹ system coupled to a gas chromatograph operating with a mass-selective detector. A total of 68 compounds of the following chemical families were detected: hydrocarbons, fatty acids, esters, sulphur and carbonyl compounds and (especially) alcohols. Most of the volatile compounds extracted with the purge and trap appeared in all seasons, but at different concentrations. This allowed a discriminate analysis to classify the samples by the season in which they were made.