The effect of putrescine and heat treatment on postharvest quality of pear fruit (Pyrus communis cv. Spadona)

In this study، the effect of pre-and post-harvest treatment of putrescine as well as heat treatment were evaluated on quality and storage life of pear fruit «Spadona». The factorial experiment was conducted using a completely randomized design of three replications. During growth season، fruits were sprayed with four levels of putrescine (0، 0. 5، 1، 2 mM) at three stages including 30، 60 and 90 days after full-bloom. After harvest، the same fruits were dipped in the putrescine (at the same concentration of pre-harvest treatment)، and hot water at 3 levels (40، 50 °C and control) for 5 min. After treatment، fruits were stored for 21 weeks at 0 ± 1°C and 80-85% relative humidity. During the storage period، fruits were carried out every three weeks and some of their qualitative and quantitative traits such as weight loss، firmness، pH، titrable acidity، total soluble solids، flavor index were measured. Result showed that the application of 1 and 2 mM putrescine treatments during pre- and post-harvest، maintained fruit firmness، decreased weight loss from fruit skin، and retarded changes in pH as well as titrable acidity compared to the control. Also، TSS and flavor index were higher at beginning of experiment in the treated fruits while at final stages، TSS was increased compared to the control. Heat treatment at 40 and 50 °C for 5 min increased TSS and fruit flavor index، but did not affect weight loss، fruit firmness، pH and titrable acidity.