The aim of this study was to investigate the influence of medium components on γ-aminobutyric acid (GABA) enrichment during soybean sprouting and further to optimize the variables by response surface methodology (RSM).Furthermore,the mechanism of GABA accumulation in germinated soybean under low salt stress was also preliminarily investigated.The results demonstrated that soybean germination in the optimized medium containing 1.0 mg/mL sodium glutamate (MSG),2.0 mmol/L pyridoxal phosphate (PLP),2.0 mmol/L CaC12 and 100 mmol/L NaCl yielded accumulation of a high level of GABA,(269.93 ± 4.73) mg/100 g dry weight,which was around 11 times higher compared with ungerminated soybeans (control).With increasing concentration of NaCl and extending stress time,glutamine acid decarboxylase activity and GABA content of sprouted soybean increased.Correlation analysis indicated that there was a significantly positive correlation between the GABA content of sprouted soybean and sprout length,glutamine acid decarboxylase activity,free amino acids content or soluble protein content.The germination of soybeans was restrained,the GAD activity was enhanced,and the contents of free amino acid and soluble protein were increased under low salt stress.Finally,GABA was accumulated at a high level.%以东北大豆为原料,研究培养液组分对大豆发芽富集γ-氨基丁酸(γ-aminobutyric acid,GABA)的影响,利用响应面法优化了大豆发芽富集GABA的培养液组分,在此基础上对低盐胁迫下大豆发芽富集GABA的机理进行研究.结果表明:优化后有效的培养液组分为谷氨酸钠1.0 mg/mL、磷酸吡哆醛2.0 mmol/L、CaCl2 2.0 mmol/L、NaC1 100 mmol/L,在此条件下,富集得到的发芽大豆中GABA含量较高,为(269.93±4.73) mg/100 g,比大豆发芽前提高了约10倍;盐胁迫下,发芽大豆谷氨酸脱羧酶(glutamate decarboxylase,GAD)活性和GABA含量随NaCl浓度加大和胁迫时间延长而提高,同时大豆发芽期间GABA含量与其他指标之间相关性分析表明,盐胁迫下发芽大豆GABA含量与芽长、GAD活性、游离氨基酸和可溶性蛋白含量之间呈显著正相关,在低盐胁迫下,大豆发芽受到抑制,但促进了GAD活性的升高,游离氨基酸和可溶性蛋白质含量增加,富集产生了较多的GABA.
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