Beschreibung:
<jats:p> Sorption isotherms of elecampe ( Inula helenium L.) and burdock ( Arctium lappa L.) root samples were obtained at 25 °C. Elecampe exhibited hysteresis loop in the range of 0.35–0.90 a<jats:sub>w</jats:sub>, whereas burdock roots showed significant differences between adsorption and desorption isotherms from 0.65 to 0.80 a<jats:sub>w</jats:sub>. Blahovec–Yanniotis was considered to give the best fit over the whole range of a<jats:sub>w</jats:sub> tested. Various parameters describing the properties of sorbed water derived from GAB, Henderson and Blahovec–Yanniotis models have been discussed. Differential scanning calorimetric method was used to measure the glass transition temperature ( T<jats:sub>g</jats:sub>) of root samples in relation to water activity. The safe moisture content was determined in 12.01 and 14.96 g/100 g d. b. for burdock and elecampe root samples at 25 °C, respectively. Combining the T<jats:sub>g</jats:sub> line with sorption isotherm in one plot, it was found that the glass transition temperature concept overestimated the temperature stability for both root samples. </jats:p>