Stevia rebaudiana hot water extracts were shown to have highly antioxidant activity against sardine oil and linoleic acid. The most active fraction which was reported in the previous paper contained large amounts of potassium. The activity was decreased by the removal of cations from the fraction by ion exchange chromatography. The activity was recovered by the addition of potassium carbonate to the fraction from which cations were removed. It was suggested that the potassium ion participated in the antioxidant activity of S. rebaudiana. When antioxidant activities of inorganic salts were investigated, it was ascertained that potassium carbonate (K2CO3), potassium bicarbonate (KHCO3), sodium phosphate (Na3PO4), potassium chloride (KCl) and sodium carbonate (Na2CO3) functioned as antioxidant compounds against linoleic acid. The most active inorganic salt was potassium carbonate. It was suggested that the function of the antioxidant activities of S. rebaudiana was mainly due to the scavenging of free radicals and next to the scavenging of superoxides. The activity of potassium carbonate was also mainly due to the scavenging activity of free radicals.
ASJC Scopus subject areas
- Food Science