MICROWAVE-ASSISTED EXTRACTION OF PHENOLIC ANTIOXIDANTS FROM SEMIARID PLANTS

Microwave-Assisted Extraction (MAE) kinetic in three temperatures was investigated for extraction of antioxidant phenolic compounds from Jatropha dioica, Flourensia cernua, Eucalyptus camaldulensis and Turnera diffusa which are plants of semiarid regions of Mexico. The two-site kinetic model and saturation simple equation were used to describe the experimental data. The fit of the data demonstrated that saturation simple equation was better and could explain the data with a slight loss of goodness of fit. The results showed that MAE optimum conditions were extraction temperature of 60°C and extraction time in the range from 1 to 6 min. The MAE was more efficient than the conventional Heat Reflux Extraction (HRE). Maximal antioxidant potential was observed in E. camaldulensis extracts. Interestingly differences in phenolic composition and antioxidant activity were observed in the extracts obtained by MAE and HRE for all plants used. Quercetin and catechin were found to be the predominant phenolic compounds. The MAE procedure resulted in suitable alternative to obtain bioactive phenolic compounds from semiarid plants due to this technology is higher efficient than conventional methods increasing yield in shorter times.