| Korla fragrant pear is one of the most famous specialty fruits in the horticultural crops of Xinjiang. The fruits are popular with consumers because of its good quality and full-bodied flavor. The fragrant pear has an excellent storage, but pear fruits easily become yellow and greasiness, which affect appearance quality of fragrant pear postharvest and bring serious economic losses, in addition this is the main factor for fragrant pear postharvest storage. In this study, Korla fragrant pear was used as test material, and improved a brief and effective sample preparation method for scanning electron microscope to observe the epicuticular wax of Korla fragrant pear, and also establishing a method for extracting epicuticular wax of Korla fragrant pear. Based on methods above, the epicuticular wax of Korla fragrant pear that with1-MCP treatment and untreated were isolated and identified by GC-MS and FTIR technology,which was expected to offer reference for researching the relationship between epicuticular wax and storage characteristics of fragrant pear and superior method for preservation of fragrant pear postharvest.The results were as follows:(1) Korla fragrant pear fruits were treated with 1μL/L 1-MCP, comparison with the untreated fruits. After treating some pear fruits were placed in the room temperature library(20±1℃,80%~85%RH), the other were placed in the low temperature library(-1.5~0℃,90%~95% RH). Korla fragrant pear fruits epicuticular wax was treated by the different sample methods. The results showed that pre-cooled in liquid nitrogen freeze-drying method was a effective sample preparation method for scanning electron microscope to observe the epicuticular wax of Korla fragrant pear. This method was used to observe the fruits in the different storage conditions, compared with the fruits at low temperature, the epicuticular wax of the fruits at room temperature became higher, and the fruits with 1-MCP treatment became rough and thiner than the untreated fruits.(2) Korla fragrant pear fruits were placed in the room temperature library after treating with 1-MCP and untreated fruits as control. The changes of epicuticular wax content of fruits were researched by the different extraction methods during the room temperature storage. The results showed that combining the results of wax contents and microstructures,room-high-temperature method with solution CHCl3 was the most effective and simplest wax extraction method for Korle fragrant pear fruits. The content of epicuticular wax of fruits was increased and greasiness phenomenon became obvious as the extension of time. However fruits wax content with 1-MCP treatment were lower than the untreated fruits during the whole storage. The wax content of fruits at low temperature was lower than the fruits at room temperature. 1-MCP treatment could effectively restrain epicuticular wax content of fruits.(3) The chemical compositions of Korla fragrant pear fruits epicuticular wax were researched by GC-MS and FTIR technology during the different conditions. The results showed that the polarity compositions of epicuticular wax compositions of fruits changed significantly, the non-polarity compositions existed many alkanes compounds and the highest content was n C29. The alkanes compounds content of fruits with 1-MCP treatment was higher than untreated fruits. Compared with 1-MCP treatment, the untreated fruits lacked n C12 and n C31 at room temperature, fruits existed n C31 at low temperature. The absorption peak intensity of the different treatments delined significantly at 2931 cm-1、2854 cm-1 and 1735cm-1, and the absorption peak intensity of fruits with 1-MCP treatment was lower than untreated. In a word, 1-MCP could protect epicuticular wax of Korla fragrant pear fruits in the postharvest process.Key words: Korla fragrant pear; epicuticular wax structure and composition; 1-MCP... |
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