The role of ethylene on volatile formation associated with ripening was investigated on melon hybrids transformed with an aminocyclopropane-1-carboxylic acid oxidase antisense gene. The headspace of four antisense hybrid fruits was analyzed by GC/MS and compared to that of nontransformed hybrid fruit. The major volatiles extracted from nontransformed hybrids were esters, mostly acetates. However, the most potent odorants were ethyl esters, such as ethyl butanoate, and branched-chain esters, such as ethyl 2-methylpropanoate and ethyl 2-methylbutanoate. In antisense hybrids, the total volatiles were 60-85% lower than that of the nontransformed hybrids. Volatiles with low odor values, such as ethyl, 2-methylpropyl and 2-methylbutyl acetates, were half to a fifth lower than in nontransformed hybrids, whereas potent odorants, such as ethyl 2-methylpropanoate and ethyl 2-methylbutanoate, were <3% that of nontransformed hybrids. Examination of the biosynthetic pathways of volatile esters derived from amino acids demonstrates that ethylene stimulated preferentially the synthesis of the most potent odorants.

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Treatments were applied in Italy, United Kingdom, and Spain to test their effectiveness in controlling superficial scald in apples (Malus domestica Borkh.) after cold storage. In Italy where mature `Red Chief' and `Golden Delicious' were stored at 3-4C for 4 months, scald incidence was reduced by postharvest dipping in a sucrose-ester based coating, Semperfresh, formulated with the antioxidants, ascorbyl palmitate, and n-propyl gallate. In the United Kingdom and Spain, early harvested `Granny Smith' were stored at 0C for 4 and 6 months. In the United Kingdom, ascorbyl palmitate applied with Semperfresh significantly reduced scald upon withdrawal from 4 months of storage near 0C, but not after 10 days at room temperature. Bringing the apples to ambient temperature for 20 hours 1 month into cold storage reduced scald almost as much as diphenylamine application, but the beneficial effects seen after 4 months of cold storage did not persist after 6 months of storage. In Spain, controlled atmosphere storage (3% O2 + 3% CO2) was as effective as diphenylamine treatment, even after 6 months of storage; CaCl2 was slightly effective after 4 months of storage, but none of the coating treatments significantly reduced scald. Treatments applied after 6 weeks were ineffective.