Subcritical water extraction of bioactive components from red ginseng (Panax ginseng CA 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 degrees C) and extraction time (5-30 min) in SWE. The maximum yields of ginsenoside Rg3 and Rh2, which have 2 hydroxyl groups (200 degrees C), appeared at a higher temperature compared to ginsenoside Rg2 and Rh1, which have 3 hydroxyl groups (150 degrees C), in SWE. The antioxidative properties were maximized at 200 degrees 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.