Abstract

The purpose of this study was to investigate the antioxidant properties of unripened apple extracts. The amount of total flavonoids in the peel and 5/30 samples were 2.7times and 5.0 times higher than the flesh and 6/30 samples, respectively. The degree of angintensin I converting enzyme (ACE) inhibition activity in hot water extracts was higher than the other extracts. In the 5/30 sample, a $0.1\%$ concentration of unripened apple powder showed almost the same electron-donating ability with a $0.5\%$ concentration of the 6/30 sample. More than $90\%$ of the electron-donating ability was observed from the peel extracts regardless of solvents used for extraction. The nitrite-scavenging effects of acetone and methanol extracts of the 5/30 sample were the strongest at pH 1.2, and especially the $80\%$ methanol extracts exhibited a powerful scavenging effect of more than $90\%$ at pH 3.0.

Keywords

• unripened apple extracts;
• total flavonoids;
• ACE inhibiting ability;
• electron-donating ability;
• nitrite-scavenging effects.