Volatile compounds papaya

Epoxy-linalool (31) has been proposed as the biogenetic precursor of the isomeric hydroxy ethers (21)-(24) as shown in Figure 7 (16). Recently, in our studies of the precursors of papaya fruit volatiles, compound (31) was detected as a natural constituent of this fruit (17). Due to the acidity of the medium (pH 3.5), in the present study, the detection of the labile epoxy derivative (31) was not expected. From the hydroxy ethers (23) and (24), the formation of acetates is easy to understand. 

Papaya is a native fruit from America and is widely planted throughout the tropics [41], and is a crop of economic importance to tropical countries [11]. It has become a commercially important fresh fruit crop, particularly in the USA and Europe [51]. Papaya possesses a characteristic aroma, which is due to several volatile components, such as alcohols, esters, aldehydes, and sulfur compounds [11]. 

Several volatile components of papaya (Solo variety) were recovered by four methods vacuum trapping train (distillation under low temperatures with liquid nitrogen traps), codistillation-extraction (vacuum), vacuum distillation, and codistillation-extraction (1 atm) [17]. In spite of great variations due to the recovery method, the results showed that linalool was always the major compound detected for all the methods. 

Fifty-one volatile components from intact Hawaiian papayas in different ripeness stages were recovered by trapping with Tenax [18]. As expected, the greatest number of components were found in the fully ripe fruits. Linalool, followed by linalool oxide A, linalool oxide B, and ethyl acetate were the major components in the fully ripe fruits. Several compounds were also present in the four ripeness stages linalool and all aldehydes can be mentioned. 

Another investigation reported the esters as the predominant volatile components of the Maradol variety (about 41% w/w of the total volatiles) [51]. The major representative compounds in the simultaneous steam distillation-solvent extraction were methyl butanoate and ethyl butanoate. Previous work described the esters as the predominant compounds among the volatiles papayas, for example, from Sri Lanka and Colombia had 52 and 63% of esters in the total volatiles respectively [25,41]. 

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