DEVELOPMENT OF VOLATILE COMPOUNDS OF AVOCADO AND CASIMIROA DURING FRUIT MATURATION

Avocado fruits (Persea americana Mill) cv. Fuerte and white sapote (Casimiroa edulis) cv. Rotaceae cultivated in Egypt were collected at different maturity stages:green mature,commercial ripe and over ripe stages. The headspace volatiles of each maturity stage was isolated and subjected to gas chromatography- mass spectrometric analy-sis. A total of 43 components were identified in avocado aroma including; terpenes (15), esters (8), aldehydes (8), alcohols (6), ketones (2), thiazoles (l), pyridines (1), toluene and acetic acid, where as 18 compounds were, identified in casimiroa aro-ma, they contained (4) esters, (6) alcohols, (4) aldehydes, (3) terpenes and (1) ketone. Ethanol (Z)-3- hexenol and (E)-2- hexenal were the major constituents in green and ripe fruits of avocado whereas they decreased at the final stage of matu-ration. Over ripe avocado fruits had the highest content of esters (ethyl ethanoate, ethyl acetate and methyl propanoate) and terpenoides especially d-limonene and z-nerolidol. Esters and alcohols comprised more than 85% of the total concentra-tion of volatiles in casimiroa fruits during three stages of maturation. The highest content of ethyl butanoate (sweet and fruity aroma) and ethanol revealed the most prominent effect on consumer acceptability of the cosimiroa flavour attributes. It is obvious that maturation of the fruits was associ-ated with remarkable changes in the volatiles that mainly affect their flavour.