Montmorillonite-based Edible Coating Enhances the Postharvest Quality of Sweetpotato by Regulating ROS and Membrane Lipid Metabolism

The quality deterioration of sweetpotatoes easily during postharvest storage owing to their high respiration rate and accumulation of reactive oxygen species (ROS). In this study, an edible coating (MCW) assembled using montmorillonite, chitosan, and whey protein isolate was fabricated to improve the postharvest quality of sweetpotatoes, and the regulatory mechanism of the edible coating treatment on sweetpotato quality has investigated. The results confirmed that edible coating treatment had a positive effect on maintaining the appearance, firmness, colour, and sensory quality of sweetpotatoes, especially in maintaining free water, starch and soluble protein content, inhibiting respiration rate and delaying weight loss of sweetpotatoes stored at 25 degrees C for 30 d. Meanwhile, this study illuminated the MCW coating regulates ROS metabolism by upregulating superoxide dismutase, ascorbate peroxidase, and glutathione reductase gene expression, resulting in lower O-2(-center dot) content in postharvest sweetpotato. Furthermore, the relative expression of the genes encoding lipoxygenase, phospholipase C, and phospholipase D was downregulated by the edible coating treatment and contributed to lower enzyme activity, electrolyte leakage and malondialdehyde content, which further reduced the degree of membrane lipid peroxidation and effectively maintained the structure of plasma membrane and then protected the cell integrity of sweetpotato. Collectively, this study provides useful information at the transcriptional level that MCW coating can enhance the post-harvest quality of sweetpotatoes by regulating ROS and membrane lipid metabolism.