Dynamic headspace analysis of Emmental aqueous phase as a method to quantify changes in volatile flavour compounds during ripening

The headspace compounds of Emmental aqueous phase (juice) and oil were anal ysed during ripening by dynamic headspace-gas-chromatography-mass spectrome try. We first checked that peak areas varied linearly with concentrations b y using a standard addition method for 9 compounds. The slopes of linear re gression curves were 1-1800 times higher for juice than for oil, indicating that these compounds were more easily released from juice. Consequently, a lthough most flavour compounds are more concentrated in cheese oil than in cheese juice, they were similarly recovered from the headspace of both type s of samples. Eighty-two compounds were identified, 70% of them being found in both juice and oil. Alcohols and esters markedly increased in number an d concentration, essentially during the ripening in the warm room, as well as, to a lesser extend, sulphur compounds, methyl ketones, and 3-methylbuta nal, whereas the other aldehydes decreased. (C) 1999 Elsevier Science Ltd. All rights reserved.