Effects of intermittent warming on chilling index and some quality properties of " Kinnow" mandarin in cold storage

Mandarin is considered as a sensitive fruit to low temperatures and its long term cold storage would result in some disorders such as pitting and reducing quality. This experiment was done to evaluate the effects of different intermittent warming (IW) treatments on quality and longevity of “Kinnow”. IW was applied at five levels (including transfer to higher temperature 24 h a week, 48h a week, 24 h in two weeks, 48 h in two weeks and control) on fruits and the quality of fruits was analyzed at three stages (i.e. 0, 45 and 90 days after cold storage). The results showed that with increasing the storage time, fruit weight loss increased significantly and IW led to more weight loss. Other quality parameters such as TSS and titratable acidity were not affected by IW but evolution of obtained data for chilling index, electrolyte and potassium leakage demonstrated that IW treatment reduced the chilling injury symptoms effectively. Among applied IW treatments in this study, the best results were obtained for fruits that were exposed to higher temperatures 24 h a week or two weeks.