## 3 Factors Influencing Volatile Composition
### Maturity  
Many factors including cultivar, cultural practices, ripeness, harvest maturity and postharvest handling can influence the abundance of volatile compounds in fruit. Of these factors, maturity is one of the critical factors to influence the abundance of volatile compounds in fruit [93]. Ideally, fruit should be harvested at optimal eating quality to optimize volatile content for flavor. However, immature fruit are often harvested in order to increase storage and market life and minimize physical damage and disorder expression. Although immature fruit are more successfully stored and transported, flavor is often lacking due to the close relationship between maturity and volatile biosynthesis [94]. In apples, immature fruits produce low quantities of volatiles at harvest, and lose the capability of volatile production during storage more readily than mature fruit [95]. In \"Cigaline\" and \"Chandler\" varieties, C\({}_{6}\) aldehydes and alcohols products of the enzymatic breakdown of unsaturated fatty acids, are major contributors to the flavor of immature fruits in the absence of furanones and esters. During fruit ripening, levels of C\({}_{6}\) compounds decrease drastically with increasd furanone acid lactone and ester production [96]. The enhancement of volatile ester production by \"Golden Reinders\" apples at late maturity stages may have arisen mainly from greater availability of substrates, thus pointing out the relevance of regulating points located upstream of AAT in the pathway [7]. Similar to apples, harvest maturity plays a pivotal role in volatile development of strawberry fruit. C\({}_{6}\) aldehydes were identified as the major compounds in immature white fruit, while furanone and esters are present in three quarters or fully red fruit [96]. Flavor volatile development in melons is also closely linked to fruit maturity with the concentration of total volatile compounds increasing linearly with increasing maturity in cantaloupe melons [97]. [PERSON] noted that ethanol, (_Z_)-3-hexanol and (_E_)-2-hexneal, the most abundant volatiles in whole green and ripe \"Fuerte\" avocados (_Persea American_ Mill), declined with ripening, while overripe fruit had the highest ester concentration [98]. [PERSON] reported that the most abundant volatiles present in the headspace of unripe, diced \"Simmonds\" avocado were sesquiterpenes and hexanal, whereas the amounts of these compounds was greatly reduced by ripening [99]. During maturation time of avocados cv. \"Hass\" the concentration of hexanal, (_E_)-2-hexenal and 2,4-hexadienal greatly declined in amount, while acetaldehyde, methyl acetate, pentanal, and \(\beta\)-myrcene were at higher concentrations in mature fruit and may also have contributed to the overall flavor [100]. In detached \"Pluk Mai Lie\" papaya fruit, 2-ethyl-1-hexanol was found specifically in green fruit, ethyl octanoate emerged only in fully-ripe fruit. Furthermore, benzyl isothiyanate was the most abundant volatile present in fruit at every stage except full ripening. The levels of methanol and ethanol sources in fruit increasedsteadily throughout ripening, with esters formed from ethyl alcohol predominating from the half-ripe through the senescence phases. The alcohol dehydrogenase (ADH) activity in the mesocarp increased dramatically during the early ripening stages, whereas ATT was active throughout ripening [101]. [PERSON] _et al._[102] reported that all the alcohols and carbonyls, along with most of the C\({}_{6}\) compounds and terpenoids, were evident before veraison in three different flavour table-grapes, \"Jingxiu\", \"Bimeijia\" and \"Jingya\", while most of the esters were detected at or after veraison. C\({}_{6}\) compounds increased in the early period of maturation, and then decreased. Most alcohols and carbonyls tended to continuously decrease during ripening. Except for geraniol, terpenoids increased until maturation, then decreased. Some esters continued to increase after maturation.