1996 Volume 22 Issue 3 Pages 139-145
The occurrence of bitterness and changes in the production of bitter compound contents were measured to determine the effect of ethylene (100ppm, C2H4) treatment on different tissues (phloem or xylem) of mechanically wounded carrots (MWC) stored at 20°C.
Neither C2H4-treated nor untreated carrots showed any apparent decay at the wounded part in MWC during 6 days of storage. Brown pitting injury appeared on the surface at the bottom of the wounded part and a brown cavity appeared in the phloem at the side of the wounded part in the treated MWC, but untreated MWC did not develop these injuries. Bitterness was not induced by C2H4 in intact carrots and was not noted in un-treated intact carrot and MWC during 6 days of storage. Bitterness of the wounded part was significant and the bitterness of the phloem was moderate in MWC treated by C2H4.
The content of isocoumarin, one of the bitter compounds, increased significantly at the wounded part and slightly in the phloem, while in the xylem no increase was noted in MWC treated by C2H4. The accumulation of isocoumarin was not induced in either treated or untreated intact carrots, and MWC was not treated by C2H4.
Increases in phenols and reducing sugar contents and decrease in total sugar content were induced by C2H4 at the wounded part in MWC during 6 days of storage.
We concluded that the occurrence of bitterness and the accumulation of the bitter compound in the carrot were induced by C2H4 and wounding.
