Subcritical water extraction of bioactive components from red ginseng (Panax ginseng C.A. Meyer)

Subcritical water extraction (SWE) could be an eco-friendly excellent alternative to the traditional extraction method for extracting red ginseng (Panax ginseng C.A. meyer). In this study, the bioactive components of red ginseng were analyzed by varying the temperature (150–200 °C) and extraction time (5–30 min) in SWE. The maximum yields of ginsenoside Rg3 and Rh2, which have 2 hydroxyl groups (200 °C), appeared at a higher temperature compared to ginsenoside Rg2 and Rh1, which have 3 hydroxyl groups (150 °C), in SWE. The antioxidative properties were maximized at 200 °C for 20 min (total phenolic content = 49.55 ± 1.03 mg gallic acid equivalent/g red ginseng, maltol content = 1.19 ± 0.01 mg/g red ginseng, the Maillard reaction product level = 1.14 ± 0.08, and the DPPH-free-radical scavenging activity = 39.97 ± 0.16%). Extracts of red ginseng from SWE all had higher ginsenoside concentrations and antioxidative properties compared to extracts prepared using traditional extraction methods, including ethanol, hot water, and methanol.