Microwave Effects on the Flavor and Storage Quality of “Nongke Nuo 336” Sweet Corn

• Microwave increases the expression of sucrose synthase and ZmSPP2, delaying the initiation of sucrose breakdown. • Microwave reduces the expression of genes associated with abscisic acid synthesis, such as NCED, ABAH1, and ZmPYL9, thereby delaying senescence in corn. • Microwave enhances the expression of antioxidant enzyme-related genes such as POD, SOD, and GR, which helps reduce ROS concentrations. • Microwave maintains color by regulating the expression of genes involved in carotenoid and flavonoid biosynthesis. Microwave (MW) technology, characterized by its convenience and efficiency, has demonstrated significant effects on extending the shelf life of agricultural products. This study investigated the impact of MW on flavor compounds, gene expression, and metabolic processes in sweet corn. The results indicated that after 6 days of storage at room temperature, MW-treated corn maintained 12.22% soluble solids content, reduced weight loss by 9.71%, and slowed the rate of hardness increase by 41.55%. MW treatment delayed sucrose breakdown by upregulating the expression of sucrose synthase genes ( ZmSUS1, ZmSUS2, ZmSUS6 ) and sucrose-phosphate phosphatase 2 (ZmSPP2) . Simultaneously, it reduces the expression of genes such as α-amylase (ZmAMY1) , thereby hindering the conversion of sugars into starch. MW treatment significantly downregulated the expression of key enzyme genes involved in abscisic acid biosynthesis ( ZmZEP, ZmCHIL2, and ZmCFAT ), delaying postharvest senescence in sweet corn. Furthermore, MW treatment upregulated the expression of antioxidant enzyme-related genes, including peroxidase (POD), among others, enhancing the stress resistance of sweet corn and thereby extending its shelf life. Metabolomics analysis further revealed that MW treatment activated the corn's defense system, leading to the accumulation of isoquercitrin, and hyperoside, which improved its stress resistance. Notably, esters, ketones, alcohols, aldehydes, and methylated compounds, which are the main flavor components, significantly enhanced the flavor characteristics of sweet corn. These findings provide valuable insights into the effects of MW on the storage quality and flavor of sweet corn.