The biological effect of corona discharge on onions (Allium cepa L.) in a commercial storage was investigated. Surface discoloration and mold were modestly but significantly reduced by the corona discharge when onions were stored for 2 or 4 weeks with or without an additional 2 weeks of shelf life under high humidity. Corona discharge treatment also reduced airborne mold spores in the storage room. No significant changes in internal decay, firmness, sprouting, or rooting, in treated onions were found.
Fresh broccoli (Brassica oleracea L. Italica group) florets untreated or treated with 1 μL·L-1 1-methylcyclopropene (1-MCP) for 14 h, were stored at 12 °C with 0, 200, or 700 nL·L-1 ozone. Senescence parameters were evaluated after 0, 1, 2, 5, 8, or 12 days of storage. Treatment with 1-MCP delayed the yellowing of florets, and at day 5 the hue angle of 1-MCP treated florets was 116° (green) compared to 102° (yellow) for the control. Respiration rates of florets were reduced by 1-MCP for the first 5 days. The 1-MCP treatment maintained higher chlorophyll fluorescence expressed as Fv/Fm during 12 days of storage. Also, 1-MCP reduced dimethyl trisulfide production, which contributes to off-odor development in broccoli florets. Compared with the controls, florets stored in 200 nL·L-1 ozone had less mold growth and yellowed more slowly, but no differences were observed in respiration, ethylene production, or Fv/Fm. Florets stored in 700 nL·L-1 ozone were greener than florets held in air or 200 nL·L-1 ozone. Interestingly, chlorophyll fluorescence of the florets stored in 700 nL·L-1 ozone decreased significantly and at day 12, Fv/Fm was only 30% of its initial value. Ozone at 700 nL·L-1 stimulated respiration and ethylene production of florets after 1 day of storage, and caused visible damage in the form of increased weight loss and browning of the floret stem ends. Treatment of broccoli with 1-MCP alone or in combination with 200 nL·L-1 ozone maintained the quality and extended the shelf life of broccoli florets.