Effect of crude microbial enzyme pretreatment on the liberation of biological compounds and antioxidant activity of red ginseng extract

To improve the quality of red ginseng extract, the effects of crude microbial enzyme pretreatment on the liberation of biological compounds and the antioxidant activity of the extract were studied. The total ginsenoside contents in red ginseng extract pretreated with and without crude microbial enzyme were 199 and 186μg/mL, respectively. More specifically, ginsenosides with the protopanaxadiol type of aglycone moieties showed significant increases (about 10%), while the protopanaxatriol type ginsenosides were hardly changed. Ginsenosides are thermally unstable, as they may degrade during thermal extraction above 70°C, and protopanaxatriol type ginsenosides are more susceptible than protopanaxadiol type. The contents of soluble solid, reducing sugars, polyphenolic compounds, and recovery of the enzymatic-pretreated group were increased 17, 51, 10, and 17%, respectively, compared with control. Additionally, the enzymatic-pretreated red ginseng extract showed significantly higher antioxidant activity and free radical scavenging ability than control.