γ-氨基丁酸（γ-Aminobutyric Acid，GABA）是一种具有众多生理功能的活性物质，在谷物中含量普遍较低，但通过胁迫处理可以得到有效富集。该研究以荞麦为原料，重点研究了柠檬酸和亚精胺联合处理对荞麦芽GABA含量的影响，并初步解析了其作用机制。响应面优化试验发现，2 mmol/L柠檬酸和0.1 mmol/L亚精胺联合处理更有助于荞麦发芽过程中GABA的积累，含量可达12.23 mg/g，比单独处理分别提高了1.11和1.27倍。同时，分别考察联合处理下谷氨酸脱羧酶（GAD）、二胺氧化酶（DAO）和多胺氧化酶（PAO）的活力以解析GABA含量变化的原因。结果表明处理后三种关键酶的活力分别为1 204 nmol/(min.g)、18.92 U/g和3.58 U/g，较未处理和单独处理的组别有显著提高，研究结果说明柠檬酸和亚精胺联合处理可显著提高荞麦芽GABA含量，这与GABA合成途径中关键酶GAD、DAO和PAO的酶活力提高有关，而且联合处理具有一定的协同作用。该研究为富集谷物GABA提供了思路和理论依据。

γ-Aminobutyric acid (GABA) is an active substance with several physiological functions. Its content is generally low in grains, but GABA can be effectively enriched by stress treatments. In this study, the effects of combined treatments using citric acid and spermidine on the GABA content in buckwheat sprouts were studied, and the mechanism was preliminarily analyzed. Response surface optimization experiments showed that the combination of 2 mmol/L citric acid and 0.1 mmol/L spermidine was more conducive to the accumulation of GABA during buckwheat germination, and the GABA content could reach 12.23 mg/g, which was 1.11 and 1.27 times higher than that of single treatments with citric acid and spermidine, respectively. Simultaneously, the activities of glutamate decarboxylase (GAD), diamine oxidase (DAO) and polyamine oxidase (PAO) under combined treatments were investigated to analyze the reasons for the GABA content variations. The results indicated that the activities of the three key enzymes after treatments were 1204 nmol/(min.g), 18.92 U/g and 3.58 U/g, respectively, which were significantly higher than those of groups with no or single treatments. The results suggest that the combined treatment with citric acid and spermidine significantly increases the GABA content of buckwheat sprouts. This is related to the increase in the enzyme activities of GAD, DAO and PAO, which are the key enzymes in the GABA synthesis pathway, and the combined treatment exhibits a certain synergistic effect. This study provides ideas and theoretical basis for enriching GABA in grains.

国家自然科学基金面上项目（32272279）；青岛市科技计划重点研发专项（22-3-3-hygg-29-hy）