Application of Pre-storage Short Anaerobic Treatment to Improve Postharvest Quality of ‘Spadona' Pear, Poster Board #006

‘Spadona’  pears  (Pyrus communis)  grown in  Israel  are susceptible to external damages, such as, superficial scald, senescent  scald and friction browning, as well as internal breakdown, when stored in regular air at 0 °C.  In order to improve fruit quality we applied an environment-friendly, physical treatment of  low O₂ (LO2) atmosphere for 7d at 20 °C, prior to storage at 0 °C. An antifungal (Scholar 0.1%) dip was applied to all fruit prior to treatments. The effect of LO2 pre-storage treatment was compared to control (untreated fruit) and to the commercial treatment (Ethoxyquin -DeccoScald  0.15%) after 4.5 months of storage at 0 °C.  During LO2 treatment there was a gradual accumulation of CO₂ and the anaerobic metabolites, acetaldehyde and ethanol.  After 7d of LO2 treatment, O₂ had depleted from an initial 1% to 0.1%, while  CO₂  accumulated to  12.7%,  acetaldehyde to 31 ppm and ethanol to 160 ppm. During LO2 treatment the level of ethylene was almost nil.  After 7d under anaerobic conditions at 20 °C, fruit was transferred to cold storage in air at 0 °C.   During storage at 0 C ethylene production was very low in the LO2-treated fruit, 5 times less than in control and commercial fruit, even after removal to shelf life at 20 °C.  Moreover, the LO2-treated fruit exhibited lower levels of alpha farnesene and its oxidation product,  6-methyl-5-hepten-2-one (MHO), than control fruit, as determined by SPME/GC-MS technique.  After 2 months at 0 °C, there were no differences between treatments. However after 4.5 months of cold storage and an additional 5d at 20 °C,   the LO2-treated fruit suffered from very low levels of senescent scald (3.2%), as compared to high levels of this damage (60% to 90%) in commercial and control fruit respectively. Also the level of internal breakdown was significantly lower in LO2-treated fruit (6%), compared to about 70% of the commercial and control fruit.  We assume that LO2 pre-treatment, probably caused reduction in senescent scald and internal breakdown in ‘Spadona’ pear, due to reduced production of ethylene and reactive oxygen substances, such as MHO, during cold storage.