Studies on physiological and chemical changes of partially processed carrot .5. Production of bitter compounds induced by ethylene treatment in fresh-cut carrots and its suppression by low O-2 and/or high CO2 atmosphere

Partially processed carrots (PPC) were transversely cut (1 cm thick) and held at 20 degrees C and under continuous flow of air including 0, 1, 10, or 100 ppm ethylene. PPCs treated with ethylene, even at 1 ppm, became bitter and developed brown bitting injury on the cut surface. Concurrently, isocoumarin formed and the levels of phenols increased during storage of 5 days, whereas these changes were not noted in the control (0 ppm) PPC. PPCs exposed to 21% O-2, 0.2% CO2, and 20 ppm C2H4 developed bitterness and pitting injury, and formed isocoumarin and accumulated phenols, whereas low O-2 (4%) or high CO2 (18%) atmosphere delayed the onset of these changes and the combination of low O-2 and high CO2 apparently surpressed them during 5-days storage period.