The aroma of Nanguo pear directly impacts its quality. This study investigated effects of 1-methylcyclopropene treatment on aroma metabolic pathway of Nanguo pear (Pyrus ussuriensis Maxim.). Nanguo pear were treated with 0.75 μL/L 1-methylcyclopropene for 24 h at 20C immediately after harvesting, and placed at room temperature for 7 days, and then refrigerated at 0 ± 0.5C for 3 and 5 months. The control fruits (without treatment) were stored under similar conditions. Results showed that 1-methylcyclopropene treatment decreased fatty acid content and reduced activity of lipoxygenase, hydrogen peroxide repressible enzyme, pyruvate decarboxylase and alcohol acyltransferase but had no significant effect on alcoholdehydrogenase enzyme activity. The total amino acid content was higher and ester content was lower in treated fruits compared to untreated fruits. This indicates that effect of 1-methylcyclopropene is via fatty acid biosynthesis pathway and inhibition of activity of lipoxygenase, hydrogen peroxide repressible enzyme, pyruvate decarboxylase and alcohol acyltransferase.
The treatment of Nanguo pear fruit with 1-methylcyclopropene combined with refrigeration could effectively improve the quality of the commodity during the preservation at room temperature after refrigeration. Our paper investigated the effects of 1-methylcyclopropene on the metabolic pathways of aroma-related compounds in Nanguo pear and revealed the reason for the reduction of the volatile compounds. In addition, this study provides the basis to resolve the issue of reduction of aroma quality in preserved Nanguo pear.