Effects of different drying methods on phenolic composition and antioxidant activity in corn silk (Stigma maydis)

Five types of drying methods were demonstrated to dry corn silks and their effects on the constitution of phenolic and antioxidant capacities were analyzed, so as to identify the best method to preserve the quality factors of corn silk including phenolic, flavonoid, and antioxidant activity. According to the results, drying can improve the level of phenolic and flavonoid in corn silk by 2.5-3.2 folds and 1.6-3.6 folds, respectively. Drying in shade (MCS-shade) had the highest content of total phenolics and flavonoids. Eight kinds of phenolic were detected by HPLC and ferulic acid was the main component. MCS-shade also showed the highest PSC value and CAA value (no wash). Overall, MCS-shade (silks treated by shade-drying) showed the best performance and the quality of dry corn silks affected greatly by different drying methods. Novelty Impact Statement This paper showed that drying methods can greatly improve the levels of phenolic and flavonoid. Shade-drying had the best results with higher phenolic and antioxidant activity. Light may cause stress signals and increase the contents of bound flavonoid.