Table 4
Free amino acid content of detoxified Rhus verniciflua vinegar produced by fermentation with different acetic acid bacteria (unit: μg/mL)

	Free amino acid	Acetic acid bacteria
	Free amino acid	AP¹⁾	AM	GE
Essential amino acid	Threonine	53.70±4.32^a	56.63±5.09^a	58.15±5.20^a
	Valine	110.01±7.88^a	113.47±9.28^a	111.87±9.41^a
	Methionine	34.08±1.71^b	38.08±2.27^b	27.16±2.01^a
	Isoleucine	66.00±4.66^a	68.16±5.10^a	67.46±5.79^a
	Leucine	134.15±9.75^a	145.60±12.10^a	128.91±11.24^a
	Phenylalanine	117.03±8.85^a	123.90±10.58^a	120.62±11.40^a
	Lysine	108.37±7.03^a	112.81±8.96^a	109.37±10.51^a
	Total	623.34	658.66	623.54
Nonessential amino acid	Aspartic acid	68.69±5.21^c	27.66±2.50^b	2.90±0.90^a
	Serine	84.86±6.06^b	92.19±7.53^b	51.44±4.41^a
	Glutamicacid	134.00±9.99^b	97.88±8.41^b	122.30±11.73^a
	Glycine	89.83±6.45^a	92.56±7.53^a	100.94±9.62a
	Alanine	158.95±11.51^a	181.90±15.00^a	273.67±27.44^b
	Cystine	48.10±3.33^a	49.17±3.66^a	44.34±4.02^a
	Tyrosine	160.17±11.91^a	165.07±13.85^a	161.63±14.36^a
	Histidine	79.00±5.54^a	79.20±6.45a	78.08±7.16^a
	Arginine	277.74±20.40^a	296.59±24.82^a	278.28±24.56^a
	Proline	85.98±9.13^b	172.85±17.67^c	35.28±2.94^a
	Taurine	1.32±0.04^b	1.25±0.13^ab	1.12±0.05^a
	Citrulline	nd²⁾	5.53±0.37^a	3.57±3.11^a
	Hydroxy proline	2.69±4.65^a	nd	2.77±1.15^a
	Proline	85.98±9.13^b	172.85±17.67^c	35.28±2.94^a
	Total	1277.31	1434.70	1191.60
Amino acid derivative	Sarcosine	54.51±33.19^a	45.83±4.12^a	40.67±3.99^a
	a-amino adipic acid	12.06±3.21^a	17.17±1.52^b	16.42±1.55^ab
	Urea	19.56±2.15^ab	22.41±2.90^b	16.79±1.07^a
	Phosphoserine	3.86±0.14^a	3.93±0.24^a	3.87±0.18^a
	a-amino-n-butyric acid	2.55±0.25^a	8.43±0.55^b	7.06±3.63^b
	Cystationine	14.35±0.83^a	14.66±0.82^a	14.14±1.05^a
	b-Alanine	28.03±2.30^a	27.45±2.90^a	27.23±2.50^a
	b-Amino isobutyric acid	35.27±4.08^a	36.92±4.34^a	71.97±5.77^b
	g-Amino-n-butyric acid	22.83±1.91^a	28.42±2.49^b	21.44±1.98^a
	Ethanolamine	8.00±0.49^b	nd	1.83±0.27^a
	Ammonia	33.63±2.23^a	39.03±2.85^a	87.14±6.99^b
	Hydrixylysine	24.09±1.78^b	23.11±0.97^ab	20.85±1.40^a
	Ornithine	12.88±1.17^a	12.23±0.70^a	11.44±1.16^a
	3-Methylhistidine	5.23±1.10^ab	5.41±0.54^b	3.65±0.77^a
	Anserine	104.82±6.31^a	112.10±9.46^a	91.56±16.84^a
	Carnosine	5.81±0.50^a	6.10±0.66^a	5.53±0.64^a
	Total	387.48	403.2	441.59
	Total	2202.70	2322.71	2221.46

AP, Acetobacter pasteurianus KACC16934; AM, A. malorum V5-7; GE, Gluconoacetobacter entanii RDAF-S.
nd, not detected.