Subcritical water extraction of wild garlic (Allium ursinum L.) and process optimization by response surface methodology

Subcritical water extraction (SWE) was employed in order to obtain high valuable extracts from wild garlic (Allium ursinum). The influence of temperature (120-200 degrees C), extraction time (10-30 min) and added acidifier, HCl (0-1.5%) on extraction process was investigated. Analysis of variance was used to determine the fitness of the model and optimal process parameters for SWE, in order to maximize extraction yield, total phenolic compounds and total flavonoids content, and antioxidant activity. The optimal conditions for SWE were determined at temperature of 180.92 degrees C, extraction time of 10 min, and added acidifier at 1.09%. An insight into the development of Maillard reaction products during SWE was provided through measurement of 5-hydroximethylfurfural(5-HMF) and furfural (F)in all obtained extracts. No influence of 5-HMF and F on antioxidant activity was observed. Using HPLC-DAD, kaempferol derivates were identified as the major phenolic compounds in extract obtained at optimal condition.