The effect of the harvest time and drying method on the drying ratio of dandelion’s raw materials (Taraxacum officinale coll.)

Abstract

The dandelion is a plant used in herbal medicine and the processing industry. Commercially available are dry raw materials, to obtain which various drying methods are used. The aim of the study was to determine the efficiency of the drying process of the dandelion herbal raw materials, depending on the drying method. The experimental material was obtained from two harvest times (spring, autumn) and was dried in a thermal dryer at a temperature of 35°C, in ambient conditions in the sun (greenhouse) and in the shade (attic). The conducted research showed that the drying ratio, determined by dryness coefficient (the ratio of the mass of fresh to dried raw material), depends on the type of raw material and for the dandelion it is as follows: root <herb with root <leaf <flower <inflorescence shoots according to decreasing efficiency. The dandelion raw materials obtained in autumn were characterized by higher efficiency, the root drying coefficient was lower by 2.2; herb with root by 2.0; and leaves by 1.8 compared to those harvested in spring. However, the drying of raw materials harvested in autumn in ambient conditions may be difficult due to unfavorable weather conditions at that time. The analyzed drying methods did not affect the drying ratio of the dandelion raw materials. Only for the raw material harvested in spring, thermal drying turned out to be less efficient than in both ambient conditions, in the shade and in the sun. The raw material obtained from the same field and dried in the same conditions may have different drying ratio coefficient and moisture after drying, although these differences are usually small.