Table 5 Free amino acid content in detoxified Rhus verniciflua vinegar by fermentation with var ious yeast strains (unit: μg/mL)

	Free amino acid	detoxified Rhus verniciflua vinegar by fermentation with different yeast strains
		Fermivin1)	N77-4	HP1-2	Y447	N43-8	Frootzen
		Essential amino acid	Valine	75.93±14.49	107.04±16.07	93.94±0.49	107.59±8.68	141.30±15.63	126.59±2.04
Leucine	77.86±10.56		113.45±15.11	74.31±55.08	132.26±11.65	179.18±14.45	149.66±2.58
Isoleucine	40.04±4.49		60.51±9.67	53.48±0.75	61.33±4.60	83.33±7.58	77.68±1.22
Lysine	62.90±3.75		79.19±4.46	46.85±0.32	60.85±28.64	149.79±12.80	70.74±1.24
Threonine	39.45±1.41		44.09±2.08	27.90±0.33	36.88±4.21	57.65±2.44	45.74±0.97
Methionine	9.02±1.05		17.79±6.90	18.04±0.12	20.73±3.08	38.38±3.18	30.77±0.85
Phenylalanine	82.68±17.07		117.25±27.25	109.22±0.87	126.68±9.50	165.33±16.51	150.60±1.95
Tryptophan	nd2)		nd	nd	nd	nd	nd
Histidine	37.44±0.41		51.70±2.87	32.74±0.18	45.64±5.26	63.38±3.45	44.49±0.39
Total	425.32		591.02	456.48	591.96	878.34	696.27
Non- essential amino acid	Aspartic acid	45.54±9.28	63.38±18.96	45.43±0.03	62.59±20.45	133.24±14.06	89.02±1.06
	Serine	57.91±3.90	70.24±8.30	42.28±0.36	60.12±8.36	95.38±3.59	76.69±1.58
	Glutamic acid	110.62±18.79	135.87±31.85	118.72±4.83	129.94±54.78	177.20±22.29	175.99±1.35
	Glycine	75.34±15.69	90.06±14.60	76.98±0.55	108.75±32.27	108.92±13.36	114.32±1.80
	Alanine	150.22±40.95	183.60±57.02	120.94±6.09	152.24±35.32	188.57±36.23	210.09±3.16
	Cystine	25.28±1.23	30.74±2.68	26.84±0.93	32.76±3.83	37.63±1.84	32.97±0.60
	Tyrosine	107.36±28.79	152.26±34.20	121.02±0.84	94.52±41.65	198.11±23.89	91.18±1.84
	Arginine	121.46±51.21	137.44±51.27	146.51±1.38	137.65±63.11	354.82±17.25	114.23±2.15
	Proline	100.04±18.79	70.55±8.12	47.91±2.01	49.64±10.78	77.23±16.04	59.96±1.62
	Citrulline	nd	6.36±5.55	nd	4.68±4.12	nd	10.25±0.07
	Total	793.77	940.50	746.63	832.89	1371.10	1069.80
Amino acid derivative	α-amino adipic acid	5.62±0.35	10.10±3.19	9.25±0.25	7.73±1.85	17.42±2.35	12.77±0.10
	Urea	14.07±0.65	11.21±9.94	12.58±3.26	8.13±7.07	nd	16.11±1.80
	Phosphoserine	4.88±0.48	5.07±0.48	4.70±0.07	5.88±1.12	5.59±0.52	5.77±0.10
	Cystationine	4.28±0.04	4.84±0.29	4.27±0.08	3.85±1.52	4.99±0.24	4.76±0.12
	γ-amino-n-butyric acid	24.21±4.03	32.36±5.85	23.65±0.38	29.05±4.53	49.89±6.63	37.82±0.65
	Ethanol amine	3.49±3.20	9.87±8.54	nd	6.66±3.55	1.81±1.57	9.83±0.24
	Ammonia	29.13±6.98	27.10±11.78	24.99±2.46	20.52±5.93	31.60±9.78	18.24±1.14
	Taurine	0.97±0.12	2.22±0.31	0.89±0.08	2.58±2.14	2.50±1.08	2.59±0.15
	Total	95.80	222.39	171.74	229.71	162.21	311.88
Total		1,314.89	1,753.91	1,374.85	1,654.56	2,411.65	2,077.95

Fermivin, Saccharomyces cerevisiae; N77-4, Pichia kudriavzerii; HP1-2, Hanseniaspora opuntiae; Y447, Candida tropicalis; N43-8, Wickerhamomyces anomalus; Frootzen, Pichia kluyveri
nd, Not detected.