Property and Inhibition of the Hydrolysis of Ginseng Saponins by Organic Acids Neutralization in Ginseng Extract Preparations

Glucosidic bond at the position of the sapogenins was hydrolyzed easily in the lower pH, higher temperature and longer time to give prosapogenins and sugars. The glucosidic bond of saponin at the , which is secondary carbon, was relatively stable due to the low electron density of -0.2. But the bond of saponin at the position, which is tertiary carbon with the relatively high electron density of -0.3, was liable to be hydrolyzed even in weak acidic solution by the increase of heating time. On the other hand, fresh and white ginseng contained 4.12 mg/g, 13.05 mg/g of citric acid, 0.68 mg/g, 2.18 mg/g of malonic acid, 1.13 mg/g, 3.68 mg/g of oxalic acid, 2.68 mg/g, 8.62 mg/g of malic acid and 0.13 mg/g, 0.46 mg/g of succinic acid, respectively. Ginseng saponins were very stable in ginseng extract neutralized with sodium carbonate or sodium bicarbonate corresponding to the equivalent amount of the total organic acid in the ginseng.