Effects Of 1-Pent CP Combined With Modified Atmosphere On Postharvest Physiology And Preservation Of Nectarine

Nectarine is popular with consumers due to their sweetness,juiciness and nutritional value.Nectarine is a typical respiratory leap fruit with obvious respiratory peaks,which carries strong field heat after harvest.Therefore,nectarine is difficult to store for long periods at room temperature.Simultaneously,nectarine is a very sensitive fruit to low temperature,and low temperature can easily cause cold damage for nectarine fruit,thus leading to flesh browning and affecting shelf life.In this study,nectarines were used as the test material to investigate the effects of active modified atmosphere and 1-Pent CP on the physiology and storage preservation of postharvest nectarine at 20±1°C and 85%～95%relative humidity,which can provide some technical means and theoretical basis for the preservation of nectarines at ambient temperature logistics.The main findings of the study are as follows:（1）In the active modified atmosphere test,the initial gas ratios in the storage environment were set to 10%O₂+5%CO₂（10%O₂）,5%O₂+5%CO₂（5%O₂）and 3%O₂+5%CO₂（3%O₂）,respectively,and the natural atmosphere was used as the control to study the effects of modified atmosphere on the physiology and freshness preservation of postharvest nectarine under ambient conditions.The results showed that active modified atmosphere reduced the respiratory intensity of nectarine,delayed the arrival of respiratory peaks,reduced the accumulation of ethanol and acetaldehyde,and slowed down the rate of ripening and senescence of nectarines.Meanwhile,the hardness and colour of nectarine were maintained,the relative conductivity and malondialdehyde accumulation were reduced,the sensory quality of fruits was better maintained,and the loss of nutrients was inhibited in active modified atmosphere treatment.The active modified atmosphere treatment with an initial gas ratio of 3%O₂+5%CO₂ was the most effective,which could extend the storage period of nectarine by more than 3 d.（2）In the 1-Pent CP treatment test,1-Pent CP at concentrations of 0.4,0.8 and 1.2μL/L were released for fumigation for 24 h,and the treatment without 1-Pent CP fumigation was used as the control.The physiological indexes and related enzyme activities of nectarines under room temperature conditions were measured periodically.The results showed that the respiratory intensity,ethylene,ethanol and acetaldehyde contents were inhibited,the titratable acid and total sugar contents were increased,fruit softening and green to red peel were slowed down,and the increase in relative conductivity and MDA contents were better controlled.Meanwhile,1-Pent CP treatment could reduce the activity of PPO and enhance the activity of POD,which had good effects on reducing the rate of fruit browning,improving fruit resistance,and thus to delay the ripening and senescence of nectarine.1-Pent CP at 0.8μL/L treatment has an optimal effect on maintaining the indicators of nectarine and extended the storage shelf life of nectarine by more than 5 d.（3）In the experiment of 1-Pent CP combined with modified atmosphere treatment,nectarines were first fumigated with 0.8μL/L 1-Pent CP for 24 h,and then placed in the same storage environment as the active modified atmosphere treatment,with the initial gas ratios of 10%O₂+5%CO₂,5%O₂+5%CO₂ and 3%O₂+5%CO_2,and the non-fumigated1-Pent CP gas treatment as the control.The physiological indicators and related enzyme activities of nectarine were measured periodically under ambient conditions using the modified atmosphere treatment without fumigation of 1-Pent CP as the control（CK）.The results showed that 1-Pent CP combined with modified atmosphere treatment could effectively inhibit the respiratory intensity of nectarine,reduce the accumulation of ethylene,ethanol,and acetaldehyde,reduce PPO activity,and enhance POD activity,improve the antioxidant capacity of fruits,reduce the browning rate of the fruit,maintain the sensory quality of nectarine,and reduce the loss of nutrients.The storage period of nectarine after the complex treatment was extended by more than 3 d than that in single treatment,which provided a reference for the transportation,storage,and preservation of nectarine at room temperature logistics.