Abstract: In order to explore a new method for the preservation of fresh lotus pods, the harvested lotus pods were treated with different concentrations (2.5, 5.0, 10.0, 15.0, and 20.0 mg/L) of 1-(2-chloropyridin-4-yl)-3-phenylurea (CPPU). By analyzing the sensory qualities of lotus pods and seeds, the color difference of lotus seed coats and the protein content of lotus seeds, the optimal concentration of CPPU was selected for the following experiments. Lotus pods without any treatment and those treated with distilled water were used as controls (CK0 and CK1). Then, the effect of CPPU treatment on browning degree, total soluble solids content, starch content, malondialdehyde (MDA) content, hydrogen peroxide (H2O2) content, the rate of superoxide anion radical (O2 -·) generation, super oxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase (POD) activity and polyphenol oxidase (PPO) activity of lotus seeds were investigated during storage at (25 ± 1) ℃. The results showed that the optimal concentration was 5.0 mg/L, and that CPPU treatment effectively prevented the browning of both lotus pods and seeds, maintaining desirable appearance, and inhibited the respiration rate of lotus pods. Moreover, this treatment inhibited the accumulation of soluble solids and starch depletion and lowered the rate of O2 -· generation and the accumulation of H2O2 and MDA. The activities of SOD and CAT were significantly improved, and the activities of POD and PPO were inhibited by CPPU treatment. In addition, the CPPU residue in CPPU-treated lotus seeds was lower than the Chinese national standard limit. Therefore, CPPU treatment is useful for improving postharvest storage quality and delaying senescence of lotus pods and seeds, and will be a promising method for extending the storage life of lotus pods.

Key words: fresh lotus pods, 1-(2-chloropyridin-4-yl)-3-phenylurea (CPPU), postharvest storage, quality, reactive oxygen species metabolism