厌氧处理对不同类型茶叶的氨基酸组成及生物活性的影响

采用经厌氧处理7 h后的同一批茶鲜叶原料,根据不同加工工艺分别制备成绿茶、白茶、乌龙茶、红茶和黑毛茶,分析其氨基酸组成和含量变化、以及其对血管紧张素转化酶(Angiotensin converting enzyme,ACE)抑制活性和抗氧化活性(包括细胞抗氧化能力以及1,1-二苯基-2-三硝基苯肼自由基清除能力、2,2...

Effects of Anaerobic Treatment on Amino Acid Composition and Biological Activities of Different Type Teas

The same batch of fresh tea leaves after 7 hours anaerobic treatment was processed into green tea, white tea, oolong tea, black tea, and dark raw tea according to different processing technologies. The amino acid composition and content, angiotensin converting enzyme (ACE) inhibitory activity were determined, and their antioxidant activities were also measured by determining cellular antioxidant activity (CAA), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging capacity, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging capacity, superoxide anion radical absorbance capacity, and ferric ion reducing antioxidant power (FRAP). Results show that the composition and content of free amino acids in different types of teas varied significantly which were processed after anaerobic treatment, and especially the content of γ-aminobutyric acid (GABA) increased significantly. The highest GABA content was found in green tea (2.21 mg·g^-1), followed by oolong tea (2.19 mg·g^-1), while the lowest in black tea (0.86 mg·g^-1). Moreover, green tea and dark raw tea showed the strongest inhibition rate of ACE (35.7% and 37.2%, respectively), while black tea showed the weakest inhibitory activity against ACE (23.8%). Additionally, it was found that green tea had the strongest antioxidant activity among the different types of teas processed from the same fresh tea leaves after anaerobic treatment.