Abstract:

This study was done to investigate the effects of controlled atmospheres with different levels of O2 and CO2:
100% O2, 80% O2 + 20% CO2, 60% O2 + 40% CO2, 40% O2 + 60% CO2 and 20% O2 + 80% CO2 on reactive oxygen
metabolism and quality preservation of broccoli (Brassica oleracea L) during storage at 15 ℃ in comparison to natural air as
a control. Results showed that the 100% O2 treatment increased the respiration rate and ethylene production, promoted the
production of hydrogen peroxide (H2O2) and superoxide anion radical (O－2 ·) and the accumulation of malondialdehyde
(MDA) content, accelerated the losses of chlorophyll and vitamin C (VC) content, and shortened the shelf life of broccoli.
Although chlorophyll content was well maintained, the 20% O2 + 80% CO2 treatment promoted the loss of VC content and
led to off-flavor whereas the 40% O2 + 60% CO2 treatment exhibited excellent storage characteristics, which dramatically
decreased the respiration rate and ethylene production, reduced the production of H2O2 and O－2 ·, delayed the accumulation
of MDA, and maintained higher contents of VC and chlorophyll. These observations demonstrate that treatment with a
combination of O2 and CO2 in proper concentration ratio could have good effects on the maintenance of broccoli quality
during storage.

Key words: broccoli, controlled atmospheres, storage, active oxygen, high O2, high CO2