Low oxygen pre-storage treatment is effective in reducing chilling injuries of deciduous fruit

Apple and pear fruits stored at low temperatures may suffer from chilling injury symptoms, caused by oxidative stress. Application of a low-oxygen (LO
2
) atmosphere (0.5%) for 10 d at 20°C or 500 ppb 1-methylcyclopropene (1-MCP) at 20°C for 24 h, prior to cold storage at 0°C, were equally effective in reducing superficial scald on ‘Granny Smith’ apples, after six months of cold storage at 0°C plus seven days at 20°C. Compared to untreated control fruit, the LO
2
and 1-MCP-treated fruit produced less ethylene,
a
-farnesene and its oxidation product, 6-methyl-5-hepten-2-one (MHO), as determined by SPME/GC-MS technique. In addition, LO
2
pretreatment applied to Californian ‘Bartlett’ or Israeli ‘Spadona’ pears, was effective in reducing superficial scald, senescent scald and internal breakdown, after 4–4.5 months of cold storage at –1°C or 0°C, respectively, plus five to seven days at 20°C. We assume that LO
2
and 1-MCP pretreated fruit remained free of physiological disorders, due to the reduced production of ethylene and the oxidation product MHO during cold storage.

Keywords: Malus domestica, Pyrus communis L. ethylene, a -farnesene, 1-MCP, low-oxygen, superficial scald