Effect of Intermittent Warming Combined with Modified Atmosphere Packaging on Chilling Injury of Plum

Plum fruit are susceptible to chilling injury (CI) when exposed to temperatures of less than 2-5 degrees C. The symptom is expressed as skin pitting, staining and flesh browning that increase in number and size over time. The effect of intermittent warming (IW) (10 or 15 days interval between 0 degrees C for 9 or 14 days and 20 degrees C for 1 day) combined with modified atmosphere packaging (MAP) with 0.04 mm PE bags was investigated on chilling injury of plums ('Ruby'). The results showed that IW combined with MAP significantly reduced CI index, skin browning index, number of CI spots and flesh browning of fruit during storage. The sensory quality of treated fruit was also maintained. After 48 days of storage, CI index of 10 and 15 days interval IW packed plum was 33 and 51% while control fruit was 100%, skin browning index was 33 and 47% compared to 100% in control fruit. Moreover the treatment also effectively maintained soluble solids content (SSC) and titratable acid (TA), and delayed membrane permeability increase. The results suggested that IW with MAP could be promising methods for plum CI controlling.