Effect of Ethylene on the Quality and Occurrence of Bitterness in Partially Processed Carrot

Partially processed carrots were prepared as two styles, lengthwise cut sectionsdivided into eight equal parts (1/8 LCS) and crosswise cut sections with 1cm thickness (1 CCS). These sections and whole carrots were exposed to continuous flow of atmosphere with or without 100ppm ethylene in air at 20°C. In 1/8 LCS and 1 CCS the occurrence of bitterness and astringency, the appearance of brown pitting injury in cut surface, the formation of isocoumarin responsible for bitterness, and rapid increase of phenols were induced by ethylene during 5days storage, whereas, these changes were not noted in whole carrots exposed to ethylene, 1/8 LCS and 1 CCS exposed to air. Partially processed carrots of 1/4 LCS were sealed in low density polyethylene (0.05mm thickness) or polypropylene (0.025mm thickness) bags into which 100ppm ethylene was injected and stored at 20°C. Ethylene did not induce bitterness of carrot in both bags during 10days storage.It is possible that the decrease of O2 concentration and the increase of CO2concentration in bags were responsible for the inhibition of producing bitter compounds by ethylene.