Organic green tea was repeatedly injected CO_2 gas to improve its product quality and chemical compositions by 6 different treatments. There were no injection (T_1), injection for 3 h (T_2), injection for 1 h and no injection for 0.5 h (T_3), injection for 2 h and no injection for 1h. by 2 times (T_4), injection for 3 h, no injection for 1.5h by 3 times (T_5), injection for 1h, no injection and injection for each 0.5 h (T_6). Among 6 treatments, T_6 treatment showed 5.24 ± 0.1% of total nitrogen, 2840 ± 25 mg 100 g^-1 of total amino acid, and 490 ± 7 mg 100 g^-1 of chlorophyll, respectively. T_5 tea sample exhibited highest amount of tannin and caffeine content with 13.95 ± 0.17% and 3.03 ± 0.08%, respectively. T_1 tea sample had the abundant amount of vitamin C with 350 ± 10 mg 100 g^-1. The longer time CO_2 gas injection resulted in less amount of aspartate and glutamate. There was no relation with theanine or arginine
content by gas injection period on organic teas. However, the amount of γ-aminobutyric acid(GABA) was 31 ± 6 mg (T_1), 219 ± 5 mg (T_2), and 315 ?9 mg (T_6) per 100g, respectively. As a result of sensory evaluation with 6 kinds of teas, T_6 tea marked the highest score with 92 ?1.9 points while T_1 with 83 ?1.5 points, and T_3 with 87 ?1.4 points.