Improving the contents of the active components and bioactivities of Chrysanthemum morifolium Ramat.: The effects of drying methods

Abstract The effect of drying methods were evaluated including hot air drying (HD), blanching-hot air drying (BHD), shade drying, microwave-hot air drying (MHD), freeze drying (FD), and vacuum-hot air drying (VHD) on the quality and bioactivities of chrysanthemum flowers. HD had the lowest total flavonoid values due to the reaction between flavonoids and oxidase during drying. Reduced activities of polyphenol oxidase and peroxidase in samples from MHD and BHD suggested that they are effective at inhibiting enzymatic browning, while the BHD could lead to the loss of some water-soluble components. Microwave treatment for 30 s combined with 75 °C hot air drying was the most effective treatment in preserving biologically active compounds, resulting in higher antioxidant capacity and greater inhibition of the enzyme acetylcholinesterase (AChE). FT-IR showed that the BHD, microwave treatment for 90 s, and VHD led to loss of more compounds than FD. This study also found that 3,5-di-caffeoylquinic acid (3,5-DCQA), luteolin-7- O -glucoside (LuG), luteolin, and kaempferol were the key bioactive substances inhibiting AChE. Furthermore, molecular docking studies showed that a high inhibition of AChE by 3,5-DCQA and LuG could be attributed to the formation of strong hydrogen bonds. The study may be beneficial for understanding C. morifolium 's nutritional value and the effects of drying methods on the quality of the final product.