A systematic comparison of the ginsenosides and physicochemical properties of white ginseng (WG), red ginseng (RG) and black ginseng (BG) was performed. The purpose of the present study was to identify the effects of the physicochemical properties by steaming process. During the steaming process, ginsenosides transform into specific ginsenosides by hydrolysis, dehydration and isomerization at C-3, C-6 or C-20. Steaming ginseng led to a significant increase in reducing sugar, acidic polysaccharide and phenolic compounds content. Antioxidative properties were investigated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, compared with BHA (Butylated hydroxyanisole). RG and BG exhibited higher antioxidant activity than WG. The maximum residue level for Benzo(a)pyrene was established to 5 μg/kg in food products. The levels of benzo(a)pyrene in WG and RG were not detected. Benzo(a)pyrene was detected in the BG, the content was 0.17 μg/kg. The scientific achievements of the present study could help consumers to choose different type of ginseng products available on the market.
Ginseng (Panax ginseng Meyer) has been used as an important medicinal plant in the orient for a long time. It exerts many activities such as DNA protective, antioxidant.and antiinflammatory. Ginseng has been identified to contain many bioactive ingredients, such as ginsenosides, phenolic compounds, acid polysaccharides and proteins. There are three preparations of ginsengs, including white ginseng (WG), red ginseng (RG) and black ginseng (BG). WG is manufactured by dehydration of fresh ginseng using sunlight, and RG is produced by steaming fresh ginseng at 95–100 °C for a reasonable time. BG is developed from WG by ninetime repetitive steaming at 95–100 °C for 3 h.
In recent decades, many studies have reported that the steaming process increased the pharmacological activities and bioactive components, compared with non-steamed ginseng. Steamed ginseng contains some specific ginsenosides (20(S)-, 20(R)-Rg3, Rk3, Rh4, Rk1, Rg5, etc.) which are absent from WG, and exhibits more potent activities on human cancer cells. BG possesses more potent biological activity than RG, such as anti-inflammatory, anti-cancer, anti-stress, and free radical scavenging pharmacological effects. Hwang et al. reported that the content of phenolic compounds and the antioxidant activity increase by increased temperature. Therefore, the analysis of ginsenosides and physicochemical properties in WG, RG and BG is significant to promote the understanding relevant factors responsible for special pharmacological effects of steaming ginseng.
Benzo(a)pyrene, a major carcinogen in grilled and broiled foods, cigarette smoke, and byproduct of many industrial processes, is used for risk assessment of the carcinogenicity based on the level of benzo(a)pyrene in food. The present study is the purpose of increasing specific ginsenosides and bioactive components by steaming process. Therefore, we evaluates a comprehensive summary of the changes of ginsenosides and physicochemical properties in WG, RG and BG.
The author investigated the effects of steaming on the physicochemical properties of white and red ginseng. During the steaming process, ginsenosides were transform into specific ginsenosides by hydrolysis, dehydration and isomerization at C-3, C-6 or C-20. Steaming ginseng led to a significant increase in the bioactive components, such as reducing sugars, acidic polysaccharides and phenolic compounds. RG and BG exhibited higher antioxidant activity than WG and standard BHA. Benzo(a)pyrene which a known potent carcinogenic were detected in BG (0.17 μg/kg) and were not detected in WG and RG.
Reference:
Jin, Yan, et al. “Effect of white, red and black ginseng on physicochemical properties and ginsenosides.” Plant Foods for Human Nutrition 70.2 (2015): 141-145.