Abstract:

In order to study the effect of CO2 concentration in O2/CO2 controlled atmosphere on chlorophyll degradation
and quality preservation in chilled broccoli, fresh broccoli were in atmospheres consisting of 50% O2 and CO2 at four
different concentration levels of 20%, 30%, 40% and 50% or air and then stored at 5 ℃. During storage, the contents of
total chlorophyll, chlorophyll a, chlorophyll b, ethanol, acetaldehyde and ascorbic acid, and the activities of chlorophyllase
and Mg-dechelatase were regularly determined. The results showed that too low or too high CO2 proportion in controlled
atmospheres had a disadvantageous effect on the storage quality of broccoli. Too high CO2 could accumulate the contents of
ethanol and acetaldehyde through anaerobic respiration. However, too low CO2 could promote the activities of chlorophyllase
and Mg-dechelatase, leading to rapid degradation of chlorophyll, yellowing and ascorbic acid loss in broccoli. Under the
experimental condition in this study, 50% O2 + 40% CO2 treatment could effectively retard chlorophyll degradation and avoid
the accumulation of ethanol and acetaldehyde and therefore have an ideal effect on quality maintenance of stored broccoli.

Key words: broccoli, carbon dioxide, oxygen, quality, controlled atmosphere, storage