Table 6.

Volatile compounds in soymilk before and after enzyme treatment

Volatile compound	KRIa	Soymilk b		Descriptionc
		Control	Enzyme treatment
Aldehydes
2-Methylbutanal	914	2.08	4.22
3-Methylbutanal	918	0.45	1.12	Dark chocolate
Pentanal	975	0.59	1.33	Grass, green
Hexanal	1074	10.53	2.86
Heptanal	1183	5.24	2.36	Rancid
Octanal	1282	4.35	2.43	Lemon, fruity
Nonanal	1387	5.87	4.87	Floral, citrus
Benzaldehyde	1513	5.14	0.84	Almond
Subtotal		34.25	20.03
Alcohols
Ethanol	931	0.48	4.69
2-Butanol	1025	1.09	3.63
2-Methyl-1-propanol	1088	2.53	1.35
3-Pentanol	1102	0.13	1.13
1-Butanol	1143	0.02	0.98
1-Penten-3-ol	1157	0.21	2.96
3-Methyl-1-butanol	1203	0.17	0.84
1-Hexanol	1352	0.98	0.23
Subtotal		4.63	15.58
Esters
Ethyl butanoate	1031	0.95	3.02
Ethyl 2-methylbutanoate	1049	0.67	3.11
Ethyl 3-methylbutanoate	1061	0.49	2.86
Ethyl hexanoate	1224	1.05	1.21
Ethyl lactate	1327	0.95	1.50
Ethyl hexadecanoate	2205	0.41	1.03
Subtotal		4.52	12.73
Acids
Acetic acid	1415	33.73	1.03	Sour
Propanoic acid	1513	4.51	1.94
2-Methyl-propanoic acid	1538	1.48	0.89
Butanoic acid	1597	3.38	1.27
Pentanoic acid	1714	0.62	1.68
Hexanoic acid	1822	1.32	1.01
Subtotal		45.04	7.82
Ketones
2-Butanone	906	0.19	1.56
2-Pentanone	973	2.14	0.90
2-Hexanone	1072	0.50	1.34
(E)-3-Penten-2-one	1116	0.14	1.73
Subtotal		2.97	5.53
Furans and furan derivatives
2-Methylfuran	873	4.03	3.78
2-Ethylfuran	954	1.15	0.7	Burnt
2-Butylfuran	1128	0.60	1.78
2-Pentylfuran	1225	0.15	1.46
Furfural	1457	0.86	11.60
2-Furanmethanol	1654	0.35	7.02
Subtotal		7.14	26.34
Sulfur-containing compounds
4-Methylthiazole	1625	0.19	0.25
2-Acetylthiazole	1636	0.13	0.71
3-(Methylthio)-1-propanol	1704	0.11	10.48
Subtotal		0.43	11.44

^aKovats retention index

^bvalues are expressed as relative area percentages

^ccited from Lv et al. [37]