POSTHARVEST QUALITY OF 'HAYWARD' KIWIFRUIT TREATED WITH 1-MCP AND STORED UNDER DIFFERENT ATMOSPHERES

The objective of this study was to assess the effect of 1-MCP on ripening and postharvest quality of 'Hayward' kiwifruit stored under different atmospheres. Two experiments were carried out with fruits harvested in a commercial orchard located in Fraiburgo (State of Santa Catarina, Southern Brazil) in April of 2003 (experiment 1) and April of 2004 (experiment 2). For experiment 1, fruit were treated with different doses of 1-MCP (0.0; 0.5 or 1.01 mu L L-1) and stored in controlled atmosphere (CA, with 2.0 kPa O-2 + 4.5 kPa CO2, at 0 degrees C +/- 0.5 degrees C/92 +/- 3% RH, and ethylene in the atmosphere <40 eta L L-1). For experiment 2, fruit were treated with 0.0 or 0.7 mu L L-1 of 1-MCP and stored in ambient atmosphere (AA; with 21.0 kPa O-2 + 0.03 kPa CO2, at 0 +/- 0.5 degrees C/90 +/- 3% RH, and 200-250 eta L L-1 of ethylene in the atmosphere) or CA (2.0 kPa O-2 + 4.5 kPa CO2, at 0 degrees C +/- 0.5 degrees C/92 +/- 3% RH, and ethylene in the atmosphere <40 nL L-1). For experiment 1, fruit were evaluated after 90 and 120 days of storage at 0 degrees C, followed by seven days at 23 degrees C. For experiment 2, fruit were evaluated after 30, 60, 90 and 120 days of storage in AA, and after 60, 90, 120 and 150 days of storage in CA, plus one and seven days at 23 degrees C. The benefits of 1-MCP treatment on fruit quality preservation were observed for fruit stored in both, AA and AC. For experiment 1, there was no difference between 0.5 and 1.0 mu L L-1 of 1-MCP on fruit ripening and postharvest quality preservation of kiwifruit stored in CA. For experiment 2, the treatment with 1-MCP delayed the increase of ethylene production rate after removal from cold storage. The reduced ethylene production in fruit treated with 1-MCP delayed the loss of flesh firmness in AC and AA, and reduced the incidence of pericarp translucency in AA. The treatment with 1-MCP increased the storage potential by 60 and 30 days for fruit stored in AA and CA, respectively.