Effects of immersion in fermented tea liquid and steam treatments on physicochemical properties and ginsenoside profiles of Korean ginseng

The study was performed to investigate some changes in physicochemical characteristics and ginsenoside profiles of Korean ginseng after being subjected to immersion in fermented tea liquid (FTL) [at a ratio of ginseng powder: FTL; 1:4, 1:6, and 1:8, w/w] and steam treatments (with and/or without steam). The ratio at 1:4 w/w showed the highest yield of bioactive components and was, therefore, selected to evaluate the effects of steam conditions [temperatures (60, 80, and 100°C) and times (1, 2, and 3 hr)]. The sample treated with FTL, regardless of the steam treatment, had darker color and higher antioxidant activity (IC50 for DPPH) than those of the control. The minor ginsenoside content increased at higher steaming temperature (100°C) and longer time (3 hr). Enhancing bioactive components of Korean ginseng by incorporating with FTL could lead to further development of various new ginseng products and might increase their health benefits for consumer’s health. Practical applications This study demonstrated that some characteristics of Korean ginseng can be altered by immersion in fermented tea “Miang” liquid (FTL) and steam treatment. The immersion treatment significantly increased antioxidant activity of Korean ginseng. Minor ginsenosides including Rh1, Rk3, Rh4, Rg3, Rk1, and Rg5 were generated when ginseng samples were steamed at 100°C. Overall, the use of immersion in fermented tea liquid in conjunction with steam treatment at 100°C could enhance bioactive components and functionality of Korean ginseng product.