Individual and combined treatments of 2,4-epibrassinolide (EBR) and calcium chloride (CaCl2) maintain the postharvest quality of baby mustard

Baby mustard is a characteristic vegetable of the Southwest China, and its quality, including appearance quality and nutritional quality, deteriorated during the postharvest senescence process. This study investigated the effects of individual and combined treatments with 2,4-epibrassinolide (EBR) and calcium chloride (CaCl2) on the visual quality and health-promoting compounds of baby mustard stored at room temperature. In terms of appearance, individual treatments with EBR and CaCl2 were more effective than the control and combined treatment in sensory evaluation and weight loss inhibition. All three exogenous treatments maintained the content of pigments, especially individual treatments. The total chlorophyll content was 1.6-, 1.6-, and 1.1-fold higher in EBR-, CaCl2-, and EBR + CaCl2-treated samples than in control samples at 4 days, respectively. In terms of nutritional quality, all three exogenous treatments delayed the decrease in glucosinolates and soluble protein content, with EBR treatment being the most effective in preserving the content of indolic glucosinolates. Additionally, three exogenous treatments effectively maintained antioxidant levels, thereby reducing hydrogen peroxide accumulation. Combined treatment inhibited brassinosteroid signaling, revealing a potential antagonistic relationship between EBR and CaCl2. The results suggest that the three exogenous treatments delayed senescence and preserved the postharvest quality of baby mustard. EBR treatment was the most effective in preserving pigments. This experiment provides potential technical and theoretical basis for the postharvest preservation of baby mustard.