Abstract:In the study Amberlite XAD-4 resin was employed as an adsorbent, which adsorbed the natural flavour sent forth from Psidium guajava L. fruit. The eluant of the adsorbate was concentrated by using a K-D concentrator. The concentrate was analyzed by dual capillary gas chromatography-mass spectrometry and temperature programed retention index on dual columns. A total of 25 substances were identified, which amounted to 98% of the total area of .the peaks. Four acetals were reported for the first time as guava components, i.e., l,l-dietho- xymethane, l,l-diethoxyethane, 1,1-diethoxyhexane and acetaldehyde ethyl cis-3-hexenyl acetal. Evaluation at an odour port during GC showed that the sharp characteristic aroma sent forth from guava fruitis attributed to l,l-diethoxymethane and l,l-diethoxyethane principally. It was discussed that the method of combining the dual column GC-MS with the dual column retention index could increase the reliability of the identification results.