Storage Stability of Nutritional Qualities, Enzyme Activities, and Volatile Compounds of "Hangjiao No. 2" Chili Pepper Treated With Different Concentrations of 1-Methyl Cyclopropene.

This study aimed to determine the effects of different concentrations of 1-methyl cyclopropene (1-MCP) on the nutritional quality, antioxidant enzyme activities, and volatile compounds of "Hangjiao No.2" chili pepper during 12 days of storage at ambient temperature. The chili fruit were randomly selected and divided into four groups corresponding to the four treatments, thus, 0.5, 1.0, and 1.5 μl L 1-MCP and a control. The analysis of the nutritional value, enzyme activities, and volatile compounds were determined at 3 days interval. The results showed that the malondialdehyde (MDA) content was lower in the fruit treated with 1-MCP compared to the control. The treatment with 1.5 μl L and the control showed the lowest superoxide dismutase (SOD) activity compared to the other treatments. Peroxidase (POD) and Catalase (CAT) were highest in the fruit treated with 0.5 μl L compared to the control and treatment with 1.0 μl L. The 1.5 μl L treatment delayed the decline in vitamin C and protein content compared to the control. Nitrate levels increased 1.34-fold at 0.5 μl L and 2.01-fold in the control. Chlorophyll content degradation was delayed at 1.0 μl L compared to the control. A total of 88 volatile compounds, including terpenes, aldehydes, alkanes, esters, alcohols, acids, phenolic derivatives, ketones, and other aromatic compounds, were detected in "Hangjiao No.2" pepper during the 12-day storage period and treatment concentrations. The production of volatile terpenes was higher in the control than in the 1-MCP treatments, while the 0.5 μl L 1-MCP treatment generally suppressed the production of volatile compounds during storage. Overall, the production of volatile compounds after treatment was higher in the "Hangjiao No.2" chili fruit treated with 1.0 μl L 1-MCP than in the other treatments throughout the storage period. The results indicate that 1-MCP treatment was more effective in maintaining fruit quality, enhancing the activities of SOD, POD, and CAT, retarding the accumulation of MDA and restoring volatile aromas, with 1.0 μl L having the best preservative effect on "Hangjiao No.2" chili fruit during storage, which could be useful for future marketing and processing.