engleski

Extraction and encapsulation of phenolic compounds from nettle (Urtica dioica L.) root

The main objectives of the presented study were: (i) to determine the influence of nitrogen fertilization (0 and 100 kg N/ha) on the content of phenolic compounds in nettle root ; (ii) to determine the retention of phenolic compounds in nettle root extract encapsulated by spraydrying. Extraction was conducted with water and 50 % aqueous ethanol using ultrasonic bath, at temperatures 70 °C during 30 min. Obtained extracts were encapsulated by laboratory scale spray dryer SD 06 at following conditions: air flow 3.5 m/s, feed flow 485 mL/h, inlet temperature 155 °C, outlet temperature in the range 72-75 °C, wall material MD 13-17 DE added to nettle root extracts in ratio 2:1. Determination of total phenols, hydroxycinnamic acids and flavan-3-ols in nettle root extracts and powders was conducted spectrophotometrically and by HPLC UV/VIS PDA. Higher amounts of all groups of phenolics were determined in nettle root with 100 kg N/ha fertilization. Encapsulation of nettle extracts under mentioned conditions resulted in high retention of phenolic compounds (89.50%). The nettle root (with and without fertilization) and nettle root powder, contained high amounts of hydroxycinnamic acids (quinic, p-coumaric, chlorogenic, ferulic acids), representing 72, 43 % of total nettle root phenols. The other phenolic compounds like rutin and p-hydrohybenzoic acids were determined in lower quantities (0.5 %, 4.5 %). The composition of nettle root extracts and their encapsulation represent a good basis for their future application in various areas of food and pharmaceutical industry.

nettle, phenolic compounds, encapsulation, HPLC

Ovaj rad je izrađen u okviru projekta „Primjena inovativnih tehnologija u proizvodnji biljnih ekstrakata kao sastojaka funkcionalne hrane“, HRZZ-3035.