Chemical characterization of polyphenols and volatile fraction of coriander (Coriandrum sativum L.) extracts obtained by subcritical water extraction

In this work, coriander (Coriandrum sativum L.) seeds were extracted by subcritical water extraction (SWE) at different temperature (100–200 °C), pressure (30–90 bar) and extraction time (10–30 min), using Box-Behnken experimental design. Polyphenol compounds in obtained extracts were analyzed by HPLC–MS/MS, and 3,4-dimethoxycinnamic acid was dominant compound with the highest yield (942 mg/100 g DW) obtained at 100 °C, 60 bar and 10 min. Chemical profile of volatile compounds was determined by GC–MS. Linalool, which is a dominant compound in coriander essential oil, was the most abundant volatile compound in all extracts obtained at 100 and 150 °C, however, it almost completely degraded at 200 °C. Total extraction yield (Y), polyphenols content (PC) and total volatile compounds (TVC) were response variables in investigated experimental design. Due to satisfactory statistical parameters, applied models for Y and PC represented good approximation of experimental results. Determined SWE conditions which provided maximized PC (1001 mg/100 g DW) were temperature of 100.5 °C, pressure of 87.6 bar and extraction time of 10 min. Even though, TVC could not be optimized by RSM due to disagreement between observed results and second-order polynomial model, it is concluded that essential oil and polyphenol compounds could be co-extracted with a good yield at optimal conditions for PC, as the highest TVC was obtained at 100 °C, 60 bar and 10 min.