Relationship between free radical scavenging activity and superficial scald in 'Rocha' pear
N. Isidoro, D.P.F. Almeida
ISHS Acta Horticulturae 800:1013-1018. 2008.
2008
บทคัดย่อ
Relationship between free radical scavenging activity and superficial scald in 'Rocha' pear
The effect of 1-methylcyclopropene (1-MCP) and diphenylamine (DPA) on the free radical scavenging activity (FRSA) and superficial scald was studied in ‘Rocha’ pear (Pyrus communis L.) fruit stored in air or in controlled atmosphere (CA). Fruit were treated after harvest with 0.1, 0.5 and 1.0 µl.L-1 of 1-MCP or with 636 mg.L-1 DPA, and stored for 200 days at 0°C and 90–95% relative humidity in air or in 2.5 kPa O2 + 0.7 kPa CO2 (balance N2). FRSA in the fruit peel was higher when fruit were stored in CA than when stored in air. 1-MCP increased the average FRSA in relation to untreated controls, but no significant effect of 1-MCP concentration was observed. 1-MCP- and DPA-treated fruit consistently showed higher FRSA than untreated controls. After 6 months in storage, 82% or 38% of fruits were affected by superficial scald in air or CA, respectively. DPA or 0.1 µl.L-1 of 1-MCP reduced scald by about 50% and higher concentrations of 1-MCP (0.5 or 1.0 µl.L-1) reduced scald by about 95%. There was a significant negative correlation between FRSA and scald (r=-0.914; P=0.028). A close, although not significant, correlation was also observed between the levels of conjugated trienols and scald (r=-0.822; P=0.088). The results suggest that peel antioxidants may have a protective role against superficial scald. However, the use of FRSA measurements to predict scald susceptibility is hindered by its fluctuations during storage.