An improvement of rose flowers drying process recovering volatile compounds by heat pump systems

Abstract

Low-Temperature drying is becoming recognized as an optimal type of hot drying technology for agricultural and sideline products. This study presents an experimental study on drying roses with a heat pump dehumidifier. The rose drying process took 40 hours across three drying stages, where the hot air temperatures were 45°C, 50°C and 55°C respectively. The dried roses were brightly colored and good quality, also, rose water was obtained during the drying process when the waste heat was recovered. The major components of the rose water were rose ether, nerol, citronellol, acetic acid, phenylethyl alcohol, methyleugenol, and so on, which are typical compounds of rose essential oil. The results show that a heat pump is one of best choices for drying rose flowers, and that rose water can also be effectively recovered during the drying process.