Fatty acids are major precursors of

Fatty acids are major precursors of aroma volatiles in most fruit [4]. Fatty acid-derived straightchain
alcohols, aldehydes, ketones, acids,
esters and lactones ranging from
C
1
to C
are importancharacter-impact aroma compounds that are responsible for fresh fruit flavors with high
concentrations, and are basically formed by three processes: α-oxidation, β-oxidation and the
lipoxygenase pathway [127]. Aroma volatiles in intact fruit are formed via the β-oxidation biosynthetic
pathway, whereas when fruit tissue is disrupted, volatiles are formed via the lipoxygenase (LOX)pathway [128]. Nevertheless, some studies suggest that increasing availability of fatty acid, along with
higher membrane permeability, during fruit ripening might allow the LOX pathway to become active
in intact plant tissue and to function as an alternative to β-oxidation [30]. Many of the aliphatic estersalcohols, acids, and carbonyls found in fruits are derived from the oxidative degradation of linoleic and
linolenic acids [16]. In addition, some of the volatile compounds derived from enzyme-catalyzed
oxidative breakdown of unsaturated fatty acids may also be produce by autoxidation [129].
Autoxidation of linoleic acid produces 9,13-hydroperoxides, whereas linolenic acid also produces
12,16-hydroperoxides [27]. Hexanal and 2,4-decadienal are the primary oxidation products of linoleic
acid, while autoxidation of linolenic acid produces 2,4-heptadienal as the major product. Further
autoxidation of these aldehydes leads to the formation of other volatile products [129].
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