Changes in volatile flavor components of guava juice with high-pressure treatment and heat processing and during storage

The changes in volatile flavor components of guava juice during pressure pr ocessing (25 degrees C, 600 MPa, 15 min), heat processing (95 degrees C, 5 min), and storage at 4 and 25 degrees C were evaluated by purge and trap/ga s chromatography/mass spectrometry. Esters were the major volatile fraction in guava juice, and alcohols were the second. Pressure processing could ma intain the original flavor distribution of the juice. Heat processing (95 d egrees C, 5 min) caused decreases in the majority of flavor components in t he juice when compared with freshly extracted juice. High-pressure treatmen t at 600 MPa for 15 min can effectively sterilize microbes but partially in activate enzymes of guava juice; therefore, volatile components in pressure -treated juice gradually changed during storage periods. Pressure-treated g uava juice showed increases in methanal, ethanol, and 2-ethylfuran with dec reases in the other components during storage period. Nevertheless, the vol atile distribution of 600 MPa treated guava juice was similar to that of fr eshly extracted juice when stored at 4 degrees C for 30 days.