本研究旨在從國產發芽豆類中，篩選出γ-胺基丁酸(gamma-aminobutyric acid; GABA)含量最高的豆類品種及探討其促進GABA生成的因子。 國產的黑豆、綠豆、大豆及紅豆共七個品種，經過27 ℃、避光及每2 h自動灑水的培養方式生產豆芽，以HPLC分析不同生長天數豆芽中GABA含量，篩選出較具有潛力的紅豆高雄九號(ABK9)及大豆台南二號(ST2)，其GABA含量分別於第七天及第八天為最高，可達1.998 mg/g d.w.及2.536 mg/g d.w.。ABK9發芽過程中麩胺酸脫羧?(glutamate decarboxylase; GAD)的活性與GABA含量變化呈現正相關性，顯示ABK9豆芽主要透過GAD轉化麩胺酸生成GABA。然而ST2在發芽五天後GABA含量卻不受GAD活性下降的影響而持續增加，且發芽過程中確有多胺含量減少以及二胺氧化?(diamine oxidase; DAO)、多胺氧化?(polyamine oxidase)活性的增加的趨勢。此意涵ST2可能是透過多胺的氧化分解作用生成GABA。許多文獻報導指出，植物在酸化、缺氧、高鹽分、缺氧、冷刺激、熱刺激等逆境環境下，會有GABA累積的現象。透過噴灑處理及浸泡處理進一步探討溫度(7-42℃)、pH值(3.5-7)、鹽類(CaCl2 10 mM或NaCl 50 mM)等因子對GABA產量之影響。結果指出，在酸性或高溫溶液的浸泡下較能有效的增加豆中的GABA含量，而發芽七天的ABK9豆芽在42 ℃、pH 4.5的條件下浸泡5 h可得到最高的GABA含量4.812 mg/g d.w.。 The aim of this study was to screen domestic legumes with highest γ-aminobutyric acid (GABA) content after germination and to study the factors to stimulate the formation of GABA. Seven kinds of legume were employed to produce sprouts under 27 ℃ in the dark and automatic sprinkling water every two hours. Based on HPLC analysis, both adzuki bean Kaohsiung No. 9 (ABK9) and soybean Tainan No. 2 (ST2) had highest GABA content of 1.998 mg/g dry matter at 7th day germination and 2.536 mg/g dry matter at 8th day germination, respectively. There was a positive correlation between glutamate decarboxylase (GAD) activity and GABA content of ABK9 during germination. It showed that formation of GABA in ABK9 during germination was mainly resulted from transforming glutamate into GABA by GAD. Whereas the increase of GABA content of ST2 after 5th day germination was not affected by the GAD activity. However, the decrease of polyamine content and increase of diamine oxidase (DAO)、polyamine oxidase(PAO) activity during germination implied that GABA in ST2 sprout might result from the oxidation of polyamines after 5th day germination. Many studies indicated that plants would accumulate GABA under stress condications such as acidic, salt, anoxia, cold, shock and heat shock. Therefore, three factors including temperature(7-42℃), pH(3.5-7) and salt (CaCl2 10 mM or NaCl 50 mM) were emplayed as stress conditions by the treatments of sprinkling and soaking to study the effects of the factors on GABA content for both ABK9 and ST2. The result showed more effective of GABA content increase in sprouts by soaking with acidic or high temperature solution. The sprout of ABK9 at 7th day germinaition had the highest GABA content , 4.812 mg/g d.w., after soaking 5 hours at 42 ℃with pH 4.5 solution
