Acetaldehyde inhibition of ethylene biosynthesis in mango fruit

Mango fruit ripening is accompanied by increased ethylene production which coordinates the ripening process. Ethylene production in other fruit has been shown to be inhibited by acetaldehyde and ethanol. In unripe mango fruit the ethylene production is very low (<1 nl g(-1) h(-1)) and treatments with acetaldehyde and ethanol had concentration-dependent effects on ethylene production. The application of 1-aminocyclopropane-1-carboxylic acid (ACC) to acetaldehyde or ethanol treated fruit discs showed acetaldehyde to be capable of completely eliminating increased ACC oxidase activity, whereas ethanol did not. This suggests that acetaldehyde is capable of inhibiting the activity of ACC oxidase directly, or alternatively of preventing the increase in the enzyme, thereby providing a possible mechanism for retarding fruit ripening.