Free and Glyclosidically Bound Volatiles in Guava Leaves (Psidium guajava L.) Palmira ICA-I Cultivar

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 capillcary GC and GC/MS analyses. A total of 39 free volatiles were detected (total amount of 1328 mu g/kg), with the major components being alpha-copaene, beta-caryophyllene, and cadina-1,4-diene. Among the 47 detected glycosidically bound compounds (total amount of 7050 mu g/kg), hexanol, benzyl alcohol, and (E)-3-hexenoic acid were found to he 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.