A poststorage burst of 6-methyl-5-hepten-2-one (MHO) may be related to superficial scald development in 'Cortland' apples
1999
Mir, N. | Pérez, R. | Beaudry, R.M.
'Cortland' apples (Malus xdomestica Borkh.), either untreated or treated with diphenylamine (DPA), were stored for 120 days in air at 0 degree C. Peel samples were taken from these fruit immediately after storage, placed in glass vials and incubated for 48 hours, or were isolated from fruit held 2 to 72 hours at 22 degrees C and incubated in the vials for 2 hours. Emission of 3,7,11-trimethyldodeca-1,3(E),6(E),10- tetraene, known as trans,trans-alpha-farnesene, or simply alpha-farnesene, and its oxidation product, MHO, were measured in the vial headspace. alpha-Farnesene content in the gas phase of vials with peel samples reached a maximal level 2 hours after vials were sealed and was higher in DPA-treated than untreated fruit. The content of alpha-farnesene in the vial headspace remained unchanged for DPA-treated fruit peel during the 2-day holding period. However, alpha-farnesene declined rapidly after 10 hours incubation for control samples. Incubating peel samples of control fruit under N(2) atmosphere prevented the decline in alpha-farnesene. The MHO release by the peel of control fruit was rapid during the first 2 hours and continued to increase for 24 hours. In contrast, the MHO released from DPA-treated fruit peels was 8000-fold lower than from peel samples of control fruit. The increase in vapor phase MHO was concomitant with peel browning in controls. For whole fruit held at 22 degrees C for 2 to 72 hours, cumulative MHO release from fruit peels followed a pattern that was similar to the pattern of superficial scald development in these fruit.
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