Antioxidant enzyme activities in strawberry fruit exposed to high carbon dioxide atmospheres during cold storage

The effects of storage, in air or a 20% CO2 in air (16.8% O2) atmosphere for 12 d at 2 °C, on antioxidant enzymes of strawberry fruit (Fragaria x ananassa Duch. cv. ‘Jewel’) were investigated. The concentrations of acetaldehyde, ethanol and ethyl acetate associated with fermentation were measured, and the activities of peroxidase (POX), catalase (CAT) and superoxide dismutase (SOD) assayed. Ethanol, acetaldehyde and ethyl acetate concentrations increased in CO2-treated fruit within a day of treatment, but more extensively after four days, while concentrations remained low in air-stored fruit. The total protein content extracted was not affected by CO2 or storage time. Activities of POX were similar in air- and CO2-treated fruit, with an increase occurring only in air-treated fruit on day-12. Neither CAT nor SOD activities were affected by CO2 treatment. In summary, a 20% CO2 storage treatment induced fermentation but did not significantly affect total antioxidant enzyme activities.