Exogenous application of acetaldehyde (AA) vapour to whole or half-peeled avocado fruits (Persea americana cv. 'Fuerte'), prior to storage, inhibited fruit ripening. This inhibition was characterized by a delay in fruit softening and a reduction in ethylene production. Activities of the cell wall depolymerizing enzymes polygalacturonase (PG), i-galactosidase (i-GAL) and endoglucanase (Cx), and of 1-aminocyclopropane-1-carboxylic acid oxidase (ACC oxidase), were reduced immediately after treatment. AA-treated fruit had reduced ethylene production and ACC oxidase activity, both in vivo and in vitro. Levels of total free sulfhydryl (SH) group compounds increased in AA-treated fruit, but diminished in untreated fruit. AA treatment inhibited fruit pulp oxidation, while untreated control fruits oxidized and became brown. Application of AA to a PG reaction mixture reduced PG activity on sodium polypectate. Pre-incubation of the substrate with AA did not result in reduced activity. Attempts to detect AA-bound proteins in AA-treated fruits were unsuccessful.

No abstract