PTR-MS monitoring of volatiles fingerprint evolution during grape must cooking

The main aim of this study was to investigate the effect of processing temperature on the evolution of volatiles during grape must concentration upon cooking. The evolution of the volatiles fingerprint of grape must heated at 80, 90, and 100 °C was studied by Proton Transfer Reaction Mass Spectrometry (PTR-MS).The intensity of the heat treatment influenced the volatile molecules generated after the activation of the non enzymatic browning (NEB) reactions during the cooking process. These volatile compounds represent the most important molecules that characterise the aroma of highly cooked and concentrated must. Time and temperature of treatment influenced dramatically the evolution of must volatile compounds, so at the end of the treatment different volatile profiles were observed. Concentration being equal, high temperature-short time treatments limited the accumulation of volatiles associated to NEB while prolonged times of treatment favoured the formation of NEB flavours.