Effect of Preharvest Aminoethoxyvinylglycine Treatment on Fruit Quality and Core Browning in ‘Huangguan’ Pear after Long-Term Cold Storage

In order to prolong the storage period of ‘Huangguan’ pear and reduce the deterioration of fruit quality during long-term storage and subsequent shelf life, this study conducted preharvest treatment with different concentrations of aminoethoxyvinylglycine (AVG) to ‘Huangguan’ pear. Before and after refrigeration for 180 days and after subsequent shelf life for 7 days, quality indicators were tested. The results showed that compared with the control group, preharvest AVG treatment delayed the decline of fruit firmness, maintained higher contents of soluble solids and titratable acids, and effectively inhibited fruit surface browning and core browning, the most pronounced effect being observed at 200 mg/L AVG. During long-term cold storage, the contents of arbutin, chlorogenic acid and total phenols increased with the occurrence of core browning, and the activity of polyphenol oxidase (PPO) increased. The expression levels of PbPAL1, PbPAL2, PbPPO1, PbPPO5, PbLOX1 and PbLOX5 were up-regulated during cold storage, but down-regulated during shelf life. Preharvest treatment with 200 mg/L AVG significantly reduced the consumption of arbutin, chlorogenic acid and total phenols, inhibited the increase of PPO activity along with the expression of PbPAL1, PbPAL2, PbPPO1, PbPPO5 and PbLOX5, and thus effectively reduced core browning in ‘Huangguan’ pear .