Inhibition of Ethylene Production and Acc Oxidase Activity in Avocado by Acetaldehyde Vapours

Exogenous application of acetaldehyde (AA) vapour (5000 ppm for 18 h) to peeled avocado fruits prior to storage caused inhibition of fruit ripening. This inhibition was characterized by a delay in fruit softening and reduction in ethylene production. Moreover, addition of 1aminocyclopropane-l-carboxylic acid (ACC), the precursor of ethylene, to avocado disks (in situ) or to avocado extract (in vitro) showed that AA reduced ethylene production by inhibiting ACC oxidase activity. CO2 production and protein levels were the same in the control and treated disks. The levels of total free sulfhydryl (SH) group compounds increased, although the total amino acids level was reduced during ripening of the AA-treated avocado. AA treatment inhibited fruit pulp oxidation, while the control fruits oxidized and became brown.