Chemical composition of the essential oil and headspace solid-phase microextraction of the guava fruit (Psidium guajava L.)

The oil and headspace of fresh white flesh guava fruits (Psidium guajava L.) from trees grown in Reunion island were obtained by steam hydrodistillation and headspace solid-phase microextraction (SPME), respectively. The chemical composition of the extract was investigated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). A total of 73 compounds were identified, of which 61 by hydrodistillation and 24 by headspace SPME. In the headspace, the major constituents were: hexanal (65.9%), gamma-butyrolactone (7.60%), (E)-2-hexenal (7.4%), (E,E)-2,4-hexadienal (2.2%), (Z)-3-hexenal (2.0%), (Z)-2-hexenal (1.0%), (Z)-3-hexenyl acetate (1.3%) and phenol (1.6%), while beta-caryophyllene (24.1%), nerolidol (17.3%), 3-phenylpropyl acetate (5.3%) and caryophyllene oxide (5.1%) were the major volatile constituents present in the hydrodistilled oil. Many compounds were identified for the first time in the guava fruit such as gamma-butyrolactone (7.6%) in the headspace SPME and nerolidol (17.6%) in the oil. In addition some compounds such as (Z)-3-hexenal, (E,E)-2,4-hexadienal, gamma-butyrolactone, borneol, phenol, cuminyl alcohol could be identified only by the headspace method (SPME).