TABLE 3.

Different GABA enrichment approaches in plants.

Product	Enrichment method	Treatment conditions	GABA concentration (mg/kg)	References
Glutinous Barley without Hull	Soaking and anaerobic treatment	Soak in 50 mmol/L sodium acetate buffer (pH 6.0) for 8 h, germinate at 15°C for 48 h, and then anaerobic treat for 12 h	143	(147)
Wheat	Hydration anaerobic treatment	After five times of hydration treatment, the wheat moisture reaches 35%, and nitrogen is added to maintain the pressure of 20 Pa for anaerobic treatment for 24 h	456.5	(148)
	Hydration heat treatment	Wheat moisture reaches 35%, blowing at 120−140°C for the 30 s, wheat grain temperature reaches 50−60°C, and then cooling to 27°C	474
Barley	Soaking treatment	Soak at 15°C, imbibe for 48 h, and germinate for 72 h	529	(149)
Wheat	Sonication treatment	After germination, 25 kHz, 28°C, 72 h ultrasonic treatment for 30 min	497.2	(150)
Soybean	Salt stress treatment	Soak in 100 mmol/L NaCl solution for 12 h at 25°C	2699.3	(151)
Bean sprout	Salt stress treatment	33.3°C, 133.5 mmol/L NaCl solution culture time 5.5 days	1205.24	(152)
Soybean sprouts	Sonication treatment	25°C, 300 W treatment for 30 min	1192.9	(153)
Soybean	Soaking treatment	30°C, soaking for 4 h, hypoxia stress for 2 days	2240	(154)
Millet	Salt stress treatment	25°C, 100 mmol/L NaCl solution salt stress treatment for 48 h	319.2	(155)
Rice	Salt stress treatment	Soak in 30 mmol/L NaCl solution at 20°C for 48 h	1138.2	(156)
Brown rice	Salt stress treatment	33.3°C, soak in 133.5 mmol/L NaCl solution for 72 h	1217.14	(157)
Rice bran	Hypoxic stress treatment	40°C, anaerobic culture under nitrogen for 8 h	1715	(158)
Rice	Treatment with different germination times	Germination at 30°C for 20 days	2850	(159)
Germinated soybean	Lactic acid bacteria fermentation treatment	MRS culture solution, at 30°C, 150 rpm, fermented soybean with lactic acid bacteria for 24 h	424.67	(160)