The effect of postharvest application of O<inf>3</inf> and 1-MCP on 'Red Chief' apple quality during prolonged air cold storage

The effects of postharvest application of 1-MCP and air storage in the presence of low O3 concentration on 'Red Chief' apple fruit quality were studied during prolonged storage. Apple fruit were harvested from two commercial orchards from 300 and 700 m elevation in the Zagora region, central Greece, during September 2012. The next day, the fruit were treated or not with 600 nl L-1 1-MCP and stored at two commercial rooms at 0°C (90-95% RH) with or without 50-60 nl L-1 O3. Apple quality was evaluated at harvest and after 2.5, 5 and 7.5 months immediately after storage and after 7 days shelf-life (20-22°C, 50-60% RH). Quality evaluation included skin color, flesh firmness, juice soluble solids content (SSC) and titratable acidity, and superficial scald incidence. Apples from the orchard at high elevation had darker redder skin color were firmer, and had lower SSC, acidity and scald incidence at harvest and during storage, than the apples from the orchard at low elevation. Fruit treated with 1-MCP kept their high quality with minor scald incidence and firmness loss even after 7.5 months cold storage in the presence or not of O3. Fruit stored with low O3 without 1-MCP treatment at harvest were of similar quality to control fruit, but had higher scald incidence. It is concluded that 1-MCP treatment at harvest, satisfactorily maintained apple fruit quality without the addition of O3 in air cold storage, while fruit not treated with 1-MCP should not be stored in the presence of low O3 concentration