Regulations and mechanisms of 1-methylcyclopropene treatment on browning and quality of fresh-cut lotus (Nelumbo nucifera Gaertn.) root slices

Abstract The quality of fresh-cut lotus root slices is greatly affected by enzymatic browning. In this study, we investigated the effects of 1-methylcyclopropene treatment on browning and quality deterioration of lotus root slices. When fresh-cut lotus root slices were immersed in 0.1 mg L−1 1-MCP for 1 h and stored at 10 ℃ for twelve days, microbial growth, respiration, total phenolic content, phenylalanine ammonia lyase activity, polyphenol oxidase activity, and soluble quinone levels in fresh-cut lotus root slices were suppressed. Furthermore, 1-MCP treatment improved the antioxidant capacities, peroxidase activities, superoxide dismutase activities, catalase activities, and DPPH free radical scavenging rates in fresh-cut lotus root slices. In addition, 1-MCP treatment inhibited the production of reactive oxide species, which delayed quality deterioration of fresh-cut lotus root slices. Based on transcriptomics and real-time quantitative PCR results, gene expression levels of NnmetK2, NnACO, NnETR2, NnEIN3, and NnERF1 were up-regulated while expression levels of NnEBF1 were down-regulated. These findings indicate that 1-MCP inhibits ethylene biosynthesis and signal transduction, which suppresses a series of ethylene-induced physiological and biochemical reactions. Based on our findings, we propose a new strategy for inhibiting enzymatic browning in fresh-cut lotus root slices.