Substantiation of the Rational Drying Conditions for the Herbal Raw Material of Goutweed (Aegopodium podagraria L.) Aerial Part

Aims: The present study aims to substantiate the rational conditions for the industrial drying of goutweed (Aegopodium podagraria L.) aerial part enabling its use in the pharmaceutical and food industries.

Methodology: The traditionally used shade drying (18–22°C for 3–5 days, sample 1) was compared with the industrial drying with the help of the original equipment presupposing mixed heat transfer (60–70°C for 90 min or 50°C for 120 min, sample 2 and sample 3, respectively). The moisture content (loss on drying) was determined, hydroxycinnamic acids and flavonoids were identified by HPLC, and the quantitative content of hydroxycinnamic acids was measured using direct spectrophotometry and spectrophotometry of the coloured complexes.

Results: It has been shown that the moisture content is comparable in all samples and there are no significant changes in the spectrum of biologically active substances identified by HPLC in the samples 2 and 3. The quantitative content of hydroxycinnamic acids is decreased in these samples that may be associated with the activation of polyphenol oxidase at the beginning of drying. Thus, the industrial drying methods do not cause principal changes in the spectrum of goutweed active substances and are advantageous in shortening the drying time. Nevertheless, the drying conditions modifications (presumably, an increase in the temperature at the beginning of drying) are needed for better preservation of hydroxycinnamic acids in goutweed raw material. The further studies will address these issues, since the shade drying, despite the possibility of obtaining of the final product with satisfactory quality (that is consistent with the previous data obtained under the laboratory conditions), is unacceptable for use in the manufacturing facilities.