UV-C irradiation reduces breakdown and chilling injury of peaches during cold storage

Pre-storage exposure of peaches (Prunus persica cv Jefferson) with UV-C irradiation for 3, 5 or 10 min significantly reduced chilling injury after 14 and 21 days of storage at 5degreesC plus 7 days of shelf-life at 20degreesC. Similar reduction in fungal decay was also found by these treatments. Skin browning and UV damage were found to be moderate to severe in peaches after the 15 or 20 min of UV-C treatments. The 20 min of exposure accelerated deterioration. Fruit treated with UV-C for 3, 5 or 10 min remained firmer and softened more slowly than the control and those treated with longer durations of exposure. No differences were found in weight loss or respiration rates among the treatments. However, ethylene production was stimulated by all of the UV-C treatments compared with the control. Putrescine levels increased initially after 3 or 5 min of exposure to UV-C. A tendency toward higher accumulation of spermidine and spermine was found in peaches after UV exposure. These higher levels of polyamines apparently are a response to the UV-C irradiation and might be beneficial in increasing the resistance of fruit tissue to deterioration and chilling injury. (C) 2004 Society of Chemical Industry.