Caracterización de compuestos volátiles en guayaba (Psidium guajava L.) variedades de Colombia

Abstract

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.