Storage and ultraviolet-induced tissue stress effects on fresh-cut pineapple

The effect of UV-induced stress on the volatile aroma compounds in cut pineapple was compared with that of storage at 4 °C for 24 h. Eighteen volatile compounds were identified by solid-phase microextraction (SPME) in fresh-cut pineapple. Methyl-2-methylbutanoate, methyl hexanoate, methyl 5-hexenoate, ethyl hexanoate and ethyl 5-hexenoate were the major aroma compounds. Storage at 4 °C for 24 h, and exposure of cut fruit to UV radiation for 15 min caused a considerable decrease in the concentration of esters and increase in the relative amount of copaene. This sesquiterpene, when added to crushed cantaloupe melon (0.1 mg g^-1), inhibited microbial growth in the fruit over a period of 24 h at 20 °C. Cis- and trans-ocimene were present in the fruit but their production was not photoinduced by UV irradiation. Ocimene, however, was a potent antimicrobial agent that killed microorganisms when added to the crushed fruit and stored at 20 °C for 24 h. The results indicate that sesquiterpene phytoalexins could contribute to the defense mechanism in wounded pineapple tissue.