Table 2.

Free amino acid content by black ginseng steaming process (Unit: mg/g).

Free Amino Acid	2022-MWG	2022-MRG	2022-MBG
L-alanine	4.68 ± 0.19	5.19 ± 0.26	4.92 ± 0.26
L-Arginine	15.49 ± 0.37	16.71 ± 0.68 *	5.24 ± 0.12 ****
L-Aspartic acid	7.96 ± 0.51	7.81 ± 0.41	6.63 ± 0.30 *
L-Cystine	0.95 ± 0.04	0.94 ± 0.05	0.63 ± 0.02 ***
L-Glutamic acid	7.10 ± 0.05	4.68 ± 0.10 ****	4.76 ± 0.09 ****
Glycine	3.06 ± 0.15	3.05 ± 0.05	3.10 ± 0.25
L-Histidine	3.07 ± 0.04	3.05 ± 0.05	1.91 ± 0.02 ****
L-Isoleucine	4.84 ± 0.07	5.03 ± 0.13	4.78 ± 0.09
L-Leucine	2.33 ± 0.09	2.35 ± 0.11	2.23 ± 0.01
L-Lysine	4.23 ± 0.09	3.15 ± 0.08 ****	0.97 ± 0.01 ****
L-Methionine	0.68 ± 0.04	0.84 ± 0.06 *	0.86 ± 0.05 **
L-Phenylalanine	3.67 ± 0.04	3.82 ± 0.07 *	3.63 ± 0.03
L-Proline	2.97 ± 0.05	2.68 ± 0.03 ***	2.57 ± 0.05 ***
L-Serine	3.26 ± 0.13	3.35 ± 0.06	3.07 ± 0.06
L-Threonine	4.23 ± 0.09	4.25 ± 0.16	3.91 ± 0.08 *
L-Tyrosine	2.88 ± 0.09	2.99 ± 0.03	2.38 ± 0.09 ***
L-Valine	2.87 ± 0.04	2.83 ± 0.04	2.75 ± 0.04 *

The data are expressed as the mean ± SD (n = 3); * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001, compared to 2022 WG.