LAUSR

ABSTRACT The dried petals of Echium amoenum Fisch. & C.A. Mey. are used for the treatment of many diseases but there are not any reports about the effects of drying conditions on their bioactive compounds. A complete 32 factorial design was used, where the independent variables were drying temperature (40°C–60°C) and air flow rate (0.5–1.0 m/s). The bioactive compounds studied were total phenolic, total flavonoid and anthocyanin contents, and antioxidant activity. The desirability index was used to predict the optimal drying conditions. Both independent variables were statistically significant. The optimal drying conditions were air velocity of 0.86 m/s at 60°C. The results show that the drying conditions play an important role in determining the final quality of the product, content of its bioactive compounds, and minimum drying time.