The γ-aminobutyric acid (GABA) content of Taiwan GABA Tea with Different Manufacturing Methods

Abstract

本試驗針對不同產區、不同季節、及不同顏色遮蔭網遮蔭處理後之茶菁為原料配合不同重複厭氧發酵次數製作之佳葉龍茶，以探討各因子間對GABA (γ-aminobutyric acid)含量的影響。以期提供台灣地區產製佳葉龍茶最適條件之參考資料。 結果顯示，影響佳葉龍茶品質變化最大的因子是厭氧發酵的次數，尤以GABA含量受發酵次數影響最顯著。不同厭氧次數對茶葉中GABA含量之影響，皆以青心烏龍茶和台茶12號在春、夏兩季之三次厭氧發酵的GABA含量最高，均提高二十倍以上。總多元酚和還原糖含量，則會隨著厭氧發酵次數增加而下降。 以名間夏季青心烏龍為材料，採用三次厭氧和二次好氣交互處理，最終GABA含量為154.99 mg/100g，高於一次厭氧處理之GABA含量(127.28 mg/100g)，而有氧攪拌則有助於GABA含量的提高，且一次有氧攪拌至三次厭氧發酵過程中總游離胺基酸和GABA含量皆呈上升的趨勢，相反地總多元酚含量則降低。 由鹿谷和龍潭茶區產製之佳葉龍茶的物化分析結果顯示，經過三次厭氧發酵處理之佳葉龍茶除總游離胺基酸含量與控制組茶樣無顯著差異外（P>0.05），其他如GABA、總多元酚、還原糖和茶湯水色均有顯著性差異（P<0.05）。台茶12號茶種所產製之佳葉龍茶GABA含量不管在春季或夏季均較青心烏龍、四季春、台茶13號者高。而在同一品種不同季節下，則是春季所產的佳葉龍茶GABA含量較夏季者高。至於茶湯水色，則是春季產製者較明亮，夏季者則較暗且顏色呈現深紅且偏暗黃。 不同色澤遮蔭網遮蔭處理之物化分析結果顯示，採用遮蔭離採摘面50 cm能有利於茶樹氨基酸之合成積聚，產製佳葉龍茶後，GABA含量皆高出未遮蔭處理者達20 mg/100g以上。三種色澤遮蔭網則以綠色的效果最好，黑色次之，橘色最差。

The main goal of this study is to investigate the influences of different production area, season, number times of anaerobic fermentation, and color of shaded materials were used as materials on the γ-aminobutyric acid (GABA) content of GABA tea. The results of this study were expected for the reference to the optimal manufacturing condition of GABA tea in Taiwan. The results showed that the GABA content of C. S. Oolong and TTES 12 tea samples was highest with fermention three times both in spring and summer. Their GABA contents were increased 20 times as compared with non-anaerobic fermented tea samples. The most important factor to influence the quality, especially GABA content of GABA tea was the number of fermentation time. The GABA content of GABA tea samples was 154.99 mg/100g with three times of anaerobic fermentation and two times of aerobic rolling interlaced. It was significantly higher than that by one time of anaerobic fermentation (127.28 mg/100g). The total free amino acid and GABA contents were become higher as the increment of times of anaerobic fermentation and aerobic rolling. But the total polyphenol content was showed the opposite tendency. The physicochemical analysis results of GABA tea samples from Lu-Gu and Long-Tan showed that the principle constituents in the GABA tea samples, such as GABA, total polyphenol, reducing sugar contents and the color of tea were different significantly from these in the control set of tea sample (p<0.05) except the total free amino acid content. In the same season, the GABA content of TTES12 was higher than that of C. S. Oolong, SJ-Chun and TTES13. The GABA tea samples with the same variety showed that the GABA content was higher in spring than in summer. The color of GABA tea samples in spring was brighter than those in summer and the GABA tea samples in summer was dark red and yellow. The physicochemical analysis results of GABA teas with different shade material treatments show that shade materials with distance 50 cm above from tea bud could contribute to amino acid synthesis, and GABA content 20 mg/100g higher than the control. The black color shade net was the best one for the increase of GABA and free amino acids content, followed by green and orange ones.