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Free and glycosidically bound volatiles obtained from the guava leaves (Psidium guajava L.) by liquid-liquid extraction and by chromatography, followed by enzymatic hydrolysis with non-selective pectinase respectively, were analyzed by capillary GC and GC/MS analyses. A total of 39 free volatiles were detected (total amount of 1328 μg/kg), with the major components being α-copaene, β-caryophyllene, and cadina-1,4-diene. Among the 47 detected glycosidically bound compounds (total amount of 7050 μg/kg), hexanol, benzyl alcohol, and (E)-3-hexenoic acid were found to be the major constituents. In aroma evaluation, the free volatile fraction showed a guava leaf-like aroma whereas the bound fraction was odorless. However, the characteristic herbaceous-green-fatty aroma was noted in the bound fraction after enzymatic hydrolysis. Upon the combination of the free and hydrolyzed bound fractions, a strongly fresh, guava leaf-like aroma was perceived.

A study of the key sulfur odor components of guava was undertaken by headspace and solvent extraction techniques. GC and GC/MS analysis identified five sulfur components; dimethyl disulfide, dimethyl trisulfide, benzothiazole, 3-mercaptohexanol and 3-mercaptohexyl acetate. Two of these compounds have not previously been reported as occurring in guava (3-mercapto- hexanol and 3-mercaptohexyl acetate). These compounds have a cassis-like odor and are thought to make an important contribution to the odor of guava.

The essential oil of the fresh plant of Spilanthes acmella Murr. from southern India was investigated by GC and GC/MS. More than 45 components have been identifi ed including (E)-2-hexenol (25.7%), 2-tridecanone (13.1%), germacrene D (11.1%), hexanol (11.0%), β-caryophyllene (10.8%) and (Z)-3-hexenol (5.1%) as signifi cantly dominating compounds. Additional components, responsible for the characteristic aroma impressions of this sample are especially C6-C9 derivatives, mono- and sesquiterpenes.

The aroma volatiles from the brown alga Cystoseira stricta var. amentacea, which is characteristic of the Aegean coastal areas of the Mediterranean sea, were isolated by a headspace technique and analyzed by GC/MS. More than seventy constituents were identified by their M S spectra and retention indices. The major constituents were cubenol (30.82%), hexanol (12.15%) and octanol (9.10%)

The volatile components of Cucumis melo ssp. dudaim (pocket melon), which were isolated by continuous extraction with isopentane, were identified by a combination of retention indices and GC/MS. Forty-eight constituents were identified in the aroma concentrate, from which hexanol (11.52%), chavicol (11.33%), (Z)-3-hexenol (6.84%), benzyl alcohol (3.54%) and eugenol (3.48%) were found to be the major constituents. The amount of chavicol found in the aroma concentrate was thought to contribute to the unique aroma character of the pocket melon.

The hydrodistilled oil of Syzygium cordatum Hochst. ex Krauss was analyzed by GC and GC/MS. The analysis revealed the presence of 22 compounds (83% of the oil) of which limonene (21.8%) and globulol (16.0%) were the major components. The identified components comprised of 8 monoterpenes and 12 sesquiterpenes. The other two compounds identified were hexanol and (Z)-3-hexenol.

The odoriferous constituents of the fruits of mandrake (Mandragora officinarum L.), a legendary and romantic Biblical plant, were studied for the first time. Ethylbutyrate (~22%), hexanol (~14%), butyl acetate (~9%) and hexyl acetate (~7%) were found to be major among fifty-five components, identified by capillary GC/MS. In addition, an unusually high proportion of sulphur containing compounds (over 7%), which contributes to the heavy, fruity and provocative odor of the mandrake fruit was also characterized.