Effect of lemon grass hot-water extracts on the quality characteristics and antioxidant activity of curd yogurt

This study was performed to examine the quality characteristics and antioxidant activity of curd yogurt with varying content (0.5-2% (w/w)) of lemon grass hot-water extract (LGHWE). The pH decreased with higher LGHWE content until 8 h, with the treated groups showing higher pH values than the control group after 12 h. The viscosity and the viable cell counts of the yogurt with 2% LGHWE were significantly lower than those of the control group during fermentation. Color values of LGHWE yogurt were lower in terms of brightness, whereas redness and yellowness values were higher compared to the control. The DPPH radical scavenging activity and soluble content significantly increased with higher LGHWE content. Consumer acceptability score of yogurt with 0.5% LGHWE was ranked higher than that of other yogurts. Yogurt containing 0.5% LGHWE showed no differences in pH and titratable acidity compared to control after storage at 4^oC for 14 days.