Physicochemical, bioactive compounds and antioxidant activities of sweet red corn under different drying methods

This study investigated the physicochemical properties, bioactive compounds, and antioxidant activities of sweet red corn under different drying methods. The color characteristics of the corn varied significantly based on the drying method employed. Freeze-drying resulted in the lightest color, while sun drying and hot air drying at different temperatures showed intermediate and varying color parameters. The total phenolic and flavonoid content decreased after drying, with heat drying methods exhibiting a greater decrease compared to freeze-drying. Microstructural analysis revealed changes in cell structure and starch granules, with freeze-dried samples displaying distinct characteristics. The sugar content decreased in all drying methods compared to the fresh sample. The amino acid content also decreased after drying, with heat drying methods affecting certain amino acids more than others. Different phenolic acids and flavonoids were detected, with their concentrations varying depending on the drying method. Fresh corn exhibited the highest antioxidant activity, while freeze-drying retained a significant amount. Sun drying and high-temperature drying methods resulted in decreased antioxidant activity. These findings underscore the importance of selecting appropriate drying techniques to preserve desired attributes and beneficial properties of corn.