A wide range of volatiles (157 compounds) have been identified, including esters, lac-
tones, aldehydes, ketones, alcohols and a group of miscellaneous compounds (Dupaigne, 1970; Flath and Forrey, 1970; Flath, 1986; Takeoka et al, 1989; Umano et al, 1992). Esters constitute over 80% of total volatiles (Umano et al., 1992). Free and glyco-sidically bound constituents have been found, including 2-pentanol, 2-butoxyethanol, hexa-noic acid, phenol, 4-hydroxybenzaldehyde, vanillin and syringaldehyde, as aglycons (Wu et al., 1991). Volatile esters increase both on the plant and after harvest (Flath, 1986). The volatiles vary with cultivar (Gray, 1953) and are higher in summer fruit, especially ethyl alcohol and ethyl acetate (Haagen-Smit et al., 1945; Silverstein, 1971). Translucent fruit are higher in ester content, such as ethyl acetate, which is very low in opaque fruit (Gray, 1953). Information on the importance of individual components to the fruit aroma and flavour is still lacking, though furaneol and ethyl-2-methylbutanoate are the two largest odour contributors (Takeoka et al., 1989).
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