| In chapter one, the domestic and foreign developments of the methods and problems existed in controlling postharvest decay of oblate-peach were summed up. The application of 1-MCP and ClO2 were reviewed. As two new fruit preservatives, 1-MCP and ClO2 has been used in many fields because of their excellent characteristic. The main biochemical enzymes correlated with the physiological and senescent processes and the aroma volatiles of fruit were also reviewed. Finally, we introduced the background and the content of our study.In chapter two, to determine the reason for the postharvest disease of fresh oblate- peach during storage, the postharvest pathogens for Xinjiang oblate-peach were deter -mined through isolating, purifing, pathogenicity determination, and identification. The efficacy of gaseous ClO2 as a sanitizer for inhibiting postharvest pathogenic germs from oblate-peach was investigated. By the bacteriostasis experiment, gaseous ClO2 exhibited variable inhibitory effects against different pathogens in different con- centration. The application of chlorine dioxide could become a successful alternative to the traditional fungicides used in postharvest disease management of oblate-peach fruit.In chapter three, the study focused on the screening of optimum 1-MCP and ClO2 concentration for harvested oblate-peach fruit. Then the changes of quality of oblate- peaches treated by 1-MCP, ClO2 and 1-MCP+ClO2 during storage were studied both at room temperature and cold storage. The results showed that by the three treatments storaged at two temperature, the ethylene release rate and respiration rate of the oblate -peaches were inhibited, firmness, contents of Vitamin C and titratable acid were well kept, and incidence of decay were lower. Compared with the effects of other fruit pre- servations, 1-MCP+ClO2 treatment combined with cold storage might be a useful way of maintaining the quality and extending shelf-life of oblate-peaches during the whole storage. But we also find a problem that oblate-peaches often have little aroma which upon removal from low temperature storage, reduce its edibleness.In chapter four, to study the mechanism and the main biochemical processes involv -ed in the enzymatic browning of oblate-peach fruit, the changes of physiology and quality of oblate-peaches treated by 1-MCP+ClO2 during storage were studied at room temperature and cold storage. The results showed that on the two conditions, compared with the control, the 1-MCP+ClO2 treatment was beneficial for maintaining the quality of oblate-peaches by reducing content of MDA and the activity of PPO and pectase (PG and PME) as well as increasing the antioxidant capacity and antioxidant enzyme.In chapter five, oblate-peaches often have little aroma which upon removal from low temperature storage, to settle this question, headspace solid-phase microextrac- tion (HS-SPME) was used to study the aroma profile characteristics of oblate-peach fruit during storage, followed by gas chromatography-mass spectrometric detection. Silica fiber coated with DVB-CAR-PDMS was found to be more efficient for collect -ing the SPME headspace volatile compounds; the extraction time of 40 min and the extraction temperature of 50℃were preferred in this study. The SPME headspace volatile constituents present in oblate-peach fruit before and after 4 weeks of cold storage have been studied, as well as some physical characteristics. The volatile compounds behaved differently during storage, a total of 58 volatiles were identified, 53 prior to storage and 44 after 4 week's storage, the content of lactones and esters, characteristic compounds of peach aroma, were much lower after 4 weeks of storage. Generally speaking, HSSPME recovered more volatiles than the conventional methods. Three methods provided representative aroma information for oblate-peach pulp. Potential bio-markers were looked for, based on the aroma profile characteris- tics by common model strategy.
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