Table 2.

GC-O-MS identification of volatiles of traditional sourdough steamed bread obtained by SPME method

Compound	RIa	Relative peak area (%)						Odorb
		Control	Hr	Sx	Hn	Gs	Hf
Aldehydes
(E)-2-Butenal	1028	–	0.91	–	–	–	–	–
Hexanal	1081	5.78	1.39	1.94	2.95	2.96	2.13	Green
Heptanal	1183	–	–	–	0.64	–	–	Planty green
(E)-2-Heptenal	1318	1.06	–	1.21	1.04	1.69	0.89	Fatty
Nonanal	1392	–	–	0.41	1.02	1.70	0.69	Slightly floral
Furfural	1460	–	2.05	7.81	2.22	4.13	6.49	–
Benzaldehyde	1515	13.27	6.78	9.38	8.56	4.62	5.83	Bitter almond
Total		20.11	11.13	20.75	16.43	15.10	16.03
Alcohols
Ethanol	925	–	32.40	9.15	18.01	13.19	11.72	Alcoholic, strong
3-Methyl-1-butanol	1198	–	2.13	1.30	8.25	–	–	Sweet, green
1-Pentanol	1247	7.01	1.05	1.27	1.00	4.26	1.71	Alcoholic
1-Hexanol	1361	19.71	26.52	28.29	15.12	25.74	36.89	–
1-Heptanol	1448	–	–	3.99	–	4.35	–	–
1-Octanol	1551	1.42	1.32	2.17	0.41	1.69	1.85	–
Phenylethyl alcohol	1903	–	3.06	3.38	27.58	7.96	2.95	–
Total		28.14	66.48	49.55	70.37	57.19	55.12
Ketones
2-Pentanone	978	–	0.63	–	–	–	–	Fruity
3-Hydroxy-2-butanone	1292	–	1.22	–	–	2.91	–	–
Total		0.00	1.85	0.00	0.00	2.91	0.00
Acids
Acetic acid	1449	–	9.02	14.03	4.60	18.84	18.17	Vinegar, acid
Hexanoic acid	1855	–	0.90	4.85	0.41	0.97	1.56	–
Total		0.00	9.92	18.88	5.01	19.81	19.73
Others
2-Pentylfuran	1231	43.95	9.68	9.14	4.88	3.77	9.12	Fruity, green
Naphthalene	1740	7.80	0.95	1.37	2.46	1.23	–	Camphoric
Total		51.75	10.63	10.51	7.34	5.00	9.12

^aRetention indices on DB-Wax column;

^bOdor perceived at the sniffing port