Preliminary Study on Ultrasonic Ageing Zhenjiang Vinegar Mechanism Based on Maillard Simulation System

Table 2

Changes in the free amino acids in the vinegar during the ageing process.

Amino acids	Amino acid content (mg/100 mL)						Taste
	Fresh	12 months	18 months	32 months	44 months	Ultrasonic treated
Asp	82.43	67.24	51.90	48.03	46.76	52.22	Sour
Glu	115.64	114.61	120.12	127.85	134.72	128.96	Fresh
Val^E	77.15	66.66	63.48	58.54	48.86	65.65	Astringent
Leu^E	107.87	92.73	85.18	82.42	78.73	89.50	Astringent
Gly	91.65	70.70	66.49	63.85	61.84	64.73	Strong sweet
Ala	118.64	103.56	94.81	90.06	83.65	94.46	Strong sweet
Thr^E	42.13	41.30	38.39	35.48	32.73	38.57	Sweet
Ser	52.49	45.15	44.46	41.94	40.89	42.27	Sweet
Met^E	13.36	14.39	13.65	12.57	9.29	12.06	Sweet
Phe^E	34.18	31.83	45.29	39.79	45.45	39.56	Sweet
Pro	61.46	38.97	43.16	32.81	35.68	36.89	Sweet
Lys^E	45.65	36.55	37.30	27.95	21.19	27.21	Slight sweet
Ile^E	47.59	51.91	45.73	40.61	37.45	46.39	Bitter
Arg	62.87	50.75	32.20	34.40	29.21	33.86	Bitter
Tyr	49.81	35.48	30.72	31.44	27.78	31.29	Slight bitter
His	27.77	15.00	16.18	11.57	10.12	16.44	Slight bitter
Trp^E	10.48	14.32	17.63	17.54	13.52	14.88	Slight bitter
Total	1041.35	891.18	836.69	796.85	757.87	843.94

E represents the essential amino acids, T represents the total amino acids, and N represents the nonessential amino acids.