Extractos aquosos de Pterospartum tridentatum L. teor de compostos fenólicos totais e actividade antioxidante

Mestrado em Engenharia Alimentar - Instituto Superior de AgronomiaCarqueja, Pterospartum tridentatum L., is a shrub common in mountainous areas and acids land, used in traditional medicine and gastronomy. In order to evaluate the eventual production of extracts of this plant, the effect of harvest period and extraction time on yield, phenolic content (PC) and antioxidant activity (AA) of the extracts was studied. Plant samples, harvested in Malcata and Gardunha mountains, were subjected to consecutive extraction steps in boiling water. After each step the aqueous phase was recovered and liophilized. The highest yield extraction was obtained in the dormancy period, with 46 and 25 % m/m (d.m) in plants of Malcata and Gardunha. It was observed at 120minutes the mass of extract recovered was on average more than 75%. No substantial variation of PC, evaluated by measuring the absorbance at 280nm in aqueous solutions, was observed throughout the consecutive extracts. PC ranged from 245 to 400 mg gallic acid equivalents per g (d.m.). Probably different phenolic compounds are extracted at different rates and there are other compounds co-extracted. The AA was determined by the radical scavenging activity method using 2,2-diphenyl-1-picrylhydrazyl radical. The greatest radical scavenging activity was observed in the flowers extracts (2mMTrolox/100g d.m.), no significant differences were observed for the different batches. Due to its AA the results suggest the interest on the production of carqueja extracts