Characterization of Wheat Germ Oil in Terms of Volatile Compounds, Lipid Composition, Thermal Behavior, and Structure

Figures & data

Table 1  Volatile compounds extracted by HS-SPME in wheat germ oil

Code	Ret. time	CAS-NO	Name	Area, %	Reference
1	2.042	64-17-5	Ethyl alcohol	0.44	[10, 15–17]
2	2.908	106-66-0	Pentane	5.48
3	3.085	513-35-9	2-Methyl-2-butene	10.43
4	6.292	110-54-3	Hexane	3.59
5	11.216	1629-58-9	1-Penten-3-one	1.15	[15]
6	12.132	590-86-3	3-Methyl-butanal	2.10	[15]
7	16.289	1576-87-0	2-Pentenal	1.02	[15]
8	17.140	71-41-0	1-Pentanol	1.03	[10, 16]
9	17.409	108-88-3	Toluene	1.05	[17]
10	18.994	111-66-0	1-Octene	2.06
11	19.768	66-25-1	Hexanal	15.97	[10, 15–17]
12	20.146	14850-22-7	3-Octene	2.48
13	20.801	7642-04-8	2-Octene	1.36
14	21.781	1002-33-1	1,3-Octadiene	0.30
15	24.021	505-57-1	2-Hexenal	0.81	[10, 15, 18]
16	24.916	100-41-4	Ethylbenzene	0.59	[15]
17	25.092	111-27-3	1-Hexanol	1.40	[10, 16–18]
18	25.629	123-92-2	3-Methyl-1-butanol	1.77	[10, 15, 16]
19	26.761	110-43-0	2-Heptanone	0.94	[10]
20	26.942	2-592-76-7	1-Heptene	0.33
21	27.592	589-43-5	Nonane	0.41
22	27.814	111-71-7	Heptanal	0.97	[10, 18]
23	29.647	56700-77-7	1,3-Nonadiene	0.53
24	30.058	7433-78-5	5-Decene	0.16
25	32.201	57266-86-1	2-Heptenal	2.68	[10]
26	33.829	3391-86-4	1-Octen-3-ol	0.65	[10, 16]
27	34.228	541-85-5	5-Methyl-3-heptanone	0.30
28	34.722	3777-69-3	2-Pentyl-furan	2.53	[10, 16]
29	35.014	123-66-0	Hexanoic acid ethyl ester	1.85	[10, 18]
30	35.278	4313-03-5	2,4-Heptadienal	8.53	[15]
31	35.660	124-13-0	Octanal	0.41	[17]
32	37.570	75135-41-0	2-(2-propenyl)-Furan	0.66
33	38.095	5989-27-5	Limonene	6.83	[10, 15–18]
34	39.817	2548-87-0	2-Octenal	0.63	[10, 15, 16]
35	42.572	1120-21-4	Undecane	0.21
36	43.043	124-19-6	Nonanal	0.66	[16–18]
37	46.943	124-07-2	Octanoic acid	7.32	[10]
38	48.972	106-32-1	Octanoic acid ethyl ester	1.22	[10]
39	49.395	629-50-5	Tridecane	0.46
40	53.725	3913-81-3	2-Decenal	0.26	[18]
41	53.973	123-11-5	4-Methoxy-benzaldehyde	0.41	[10, 17]
42	55.108	14371-10-9	Cinnamaldehyde	0.39
43	55.744	140-67-0	Estragole	7.23
44	56.876	25152-84-5	2,4-Decadienal	0.40	[17]

Figure 1 Chromatographic localization of the volatile compounds identified and quantified in wheat germ oil.

Table 2  Main unsaponifiable matter identified in wheat germ oil

Ret. time	Name	Area, %
6.095	Squalene	1.26
9.055	Cholesterol	8.79
10.880	Campesterol	21.28
12.470	β-Sitosterol	64.64
12.781	Fucosterol	4.03

Table 3  Fatty acid composition (%) of TG and Sn-2-MAG in wheat germ oil

	16:0	18:0	18:1	18:2	18:3
TG	16.27	0.28	13.19	64.82	4.91
Sn-2-MAG	0.6	—	12.11	87.29	—
—: not detected.

Figure 2 FT-IR spectrum of wheat germ oil. (Color figure available online.)

Figure 3 DSC-TGA profiles of wheat germ oil.

Figure 4 Oxidative stability curve of wheat germ oil. (Color figure available online.)