Characterization of volatile compounds in guava (Psidium guajava L.) varieties from Colombia

The guava (Psidium guajava L.), which has unique and quince-banana like flavor, is an economically important subtropical fruit in many tropical countries on all seasons. Volatile constituents from three Colombian varieties of guava fruits: Coronilla (commonly named guayaba común), Palmira ICA-1 (commonly named guayaba pera) and Glum Sali (commonly named guayaba manzana) were isolated by headspace-solid phase microextraction using 100 mm polydimethylsiloxane fibers and analyzed by gas chromatography-mass spectrometry. For each extraction, 30 g of fruits and 90 mL of 20 % NaCl solution were blended for 10 min and then centrifuged at 3 000 r/min for 10 min . A 7 g supernatant was immediately placed in a 15 mL vial. The sample was kept for 15 min to achieve the equilibrium and after them, the SPME fiber was exposed to the headspace of the sample to adsorb the volatiles for 30 min . Vials were continuously swirled with an agitation speed of 100 r/min and at 40 oC . Desorptions for 2 min into the GC injector were made at 250 oC . Ninety-seven compounds were identified in the present study, 19 of them for the first time as volatile constituents of guava. Each variety has a typical composition, characterized by a specific ratio between the main components and classes of substances. Palmira ICA-1 and Coronilla varieties had higher amount of volatile compounds than Glum Sali variety, particularly esters; while in Glum Sali variety were predominant hexanal, 2E-hexenal and acids. Major volatiles in all varieties were either 3Z-hexenyl acetate, 3-phenylpropyl acetate, (E)-cinnamyl acetate and hexanal.