Comparison of bioactive components in GABA tea and green tea produced in Taiwan

• Published in: Food chemistry 2006-06, Vol.96 (4), p.648-653
• Main Authors: Wang, Hsueh Fang, Tsai, Yung Sheng, Lin, Mu Lien, Ou, Andi Shau-mei
• Format: Article
• Language: English
• Subjects: ascorbic acid; bioactive properties; Biological and medical sciences; catechin; Coffee, tea and other stimulative beverage industries; color; epicatechin; epigallocatechin; fatty acid composition; food analysis; food composition; Food industries; food processing; free amino acids; Fundamental and applied biological sciences. Psychology; GABA; GABA tea; gamma-aminobutyric acid; Glutamic acid; Green tea; lipid content; nitrogen content; phenolic compounds; Physicochemical analyses; reducing sugars; tea; water content
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2005.02.046

The aim of this study is to investigate the bioactive components of GABA (γ-aminobutyric acid) tea as compared with green tea produced in Taiwan. Using in total 56 tea samples (28 green tea and 28 GABA tea), moisture content, Hunter L, a and b values, phenolic compounds, amino acids including GABA, fatty acids and ascorbic acid were determined. The results showed that moisture, total free amino acids, crude fat, Hunter L value, total nitrogen, free fatty acids and reducing sugar did not differ significantly between GABA tea and green tea. However, GABA tea had higher Hunter a and b values, while green tea had higher total catechin and ascorbic acid contents ( p < 0.05). Of major catechins, epicatechin and epigallocatechin gallate were found to be lower in GABA tea than in green tea. For free amino acids, GABA, alanine, ammonia, lysine, leucine and isoleucine were found to be significantly higher in GABA tea, while the glutamic acid, aspartic acid, and phenylalanine were higher in green tea ( p < 0.05). Theanine, tryptophan, valine, threonine and methionine were not found to be different between the two kinds of tea.