Influence of drying techniques on retention of anthocyanin and their antioxidant activities in chrysanthemum (Chrysanthemum x morifolium) flowers

The influence of different drying methods, viz. shade drying, hot air oven drying and microwave oven drying on total anthocyanin content, total phenolic content and their antioxidant activities (measured by CUPRAC, FRAP and DPPH assay) of dried ray florets of five anthocyanin rich chrysanthemum (Chrysanthemum × morifolium Ramat.) varieties was studied in the present investigation. Microwave oven drying was the best method w.r.t. retaining its total anthocyanin content, total phenolic content and antioxidant activities. Microwave oven drying method had retained highest total anthocyanins (208.26 mg/100g), total phenolic content (36.17mg GAE/g DW) and antioxidant activities (CUPRAC= 280.74 μmol trolox/g dry weight, FRAP= 145.26 μmol trolox/g dry weight and DPPH= 31.44%) in variety Red Gold. In microwave oven drying method, total anthocyanin content of dried ray florets revealed significantly and positively correlation with total phenolic content (0.922) and CUPRAC (0.892), FRAP (0.976), DPPH (0.904) assay of antioxidant activities. Total phenolic content also exhibited positive and significant correlation with CUPRAC (0.995), FRAP (0.982), DPPH (0.998) assay of antioxidant activities. The antioxidant activity assays of microwave dried ray florets also exhibited positive and significant correlation among themselves.