Study On The Effect Of Intermittent Warming Combined With Oxalic Acid On Chilling Injury Of Peach Fruit

Low temperature storage is an important way to prolong shelf life of peaches after harvest, but peaches are highly susceptible to temperature, so it is usually found chilling injury in peach fruit stored at low temperature for a long time. In this paper, the peach fruits of cultivar "baifeng" were used to investigate the effect of intermittent warming combined with oxide acid on keeping peach fresh, the results were as follows:1. Peaches were submitted to intermittent warming cycles of one day at20℃every6,9,14days at0℃, we found after three cycles, intermittent warming avoided or strongly alleviated chilling injuries (particularly woolliness and lack of juiciness).And peaches were treated with different concentrations of oxalic acid(1.5,10,20mmol/L), we found that treating with5mmol/L OA was most effective in reducing internal browning and flesh mealiness while maintaining higher level of peach quality. Thus we chose IW cycles of one day at20℃every9days combined with5mmol/L OA treatment.2. IW combined with OA treatment can strongly reduce the internal browning and flesh mealiness while maintain higher level of extractable juice, TSS and TA in peach fruit. They can work together to avoid each adverse effect, so the firmness of peaches remained at high level which could extend shelf life.3. During the storage time, the activities of PPO、POD and LOX were inhibited, while the activities of antioxidant enzymes such as SOD、CAT and APX were induced by IW combined with OA treatment, so the accumulation of O2-and MDA contents decreased. In addition, IW combined with OA treatment enhanced the level of GSH and total phenolic contents. On the other hand the activities of SDH、COX、H+-ATPase and Ca2+-ATPase decreased as cold storage progressed, IW combined with OA treatment can enhance their activities in order to keep the membrane integrity, so ATP、ADP、AMP contents and adenylate energy charge stay at a high level.These results suggested that the development of chilling injury might be resulted from limited energy availability.The combination of IW and OA could be a useful technique to alleviate the chilling injury of peaches.