Comparison of fatty acid profile changes between unroasted and roasted brown sesame (Sesamum indicum L.) seeds oil

Figures & data

Figure 1. Sesame seeds from Kurdistan Region–Iraq; A: unroasted brown sesame seeds, B: roasted brown sesame seeds at 200°C for 30 min on a hot plate.

Table 1. Chemical composition of unroasted and roasted brown sesame seeds, in 100 g raw seeds matter.

Component	Unroasted	Roasted
Oil content	49.1^a ± 0.8	51.1^b ± 0.7
Moisture content	4.9^a ± 0.4	3.8^b ± 0.2
Ash content	5.9^a ± 0.1	5.8^a ± 0.1
Unsaponifiables matter	1.2^a ± 0.1	1.3^a ± 0.1

All the given values are means of tree determinations ± standard deviation.

Means in a row followed by the same letters are not significantly different (p < 0.05).

Table 2. Fatty acid composition (%) of unroasted and roasted brown sesame seeds oil.

Fatty acids	(%) of fatty acids in unroasted sesame oil	(%) of fatty acids in roasted sesame oil
Myristic acid (C14:0)	0.9^a ± 0.01	0.9^a ± 0.01
Palmitic acid (C16:0)	5.6^a ± 0.9	7.1^b ± 0.9
Palmitoleic acid (C16:1n-9)	0.4^a ± 0.1	0.4^a ± 0.01
Stearic acid (C18:0)	5.3^a ± 0.8	6.8^a ± 0.6
Oleic acid (C18:1n-9)	40.3^a ± 5.3	58.7^b ± 4.7
Linoleic acid (C18:2n-9, 12)	46.1^a ± 1.1	24.8^b ± 0.9
α-Linolenic acid (C18:3n-9, 12, 15)	0.4^a ± 0.2	0.2^a ± 0.1
Arachidic acid (C20:0)	0.5^a ± 0.07	0.5^a ± 0.1
Eicosadienoic acid (C22: 0)	0.5^a ± 0.2	0.6^a ± 0.2
SFA	12.8 ± 1.98	15.9 ± 1.81
MUFA	40.7 ± 6.2	59.1 ± 4.71
PUFA	46.5 ± 1.3	25 ± 1

All the given values are means of tree determinations ± standard deviation.

Means in a row followed by the same letters are not significantly different (p < 0.05).

Figure 2. Chromatograms of GC-MS (Thermofisher) of FAMEs sesame oil; A: chromatogram of GC-MS of unroasted sesame seeds oil, B: chromatogram of GC-MS of roasted sesame seeds oil.

Table 3. Chemical shifts and assignments of the characteristic resonances in the ¹H NMR spectra of unroasted and roasted crude sesame seed oil, (400 MHz in CDCl₃).

Chemical shifts for unroasted seeds (ppm)	Chemical shifts for roasted seeds (ppm)	Proton	Assignment
0.84 (m)	0.85 (m)	-CH3	Terminal methyl
0.95 (t)	0.95 (t)	-CH3 (ω3)	Terminal methyl of polyunsaturated (ω3)
1.23 (bp)	1.23 (bp)	CH2n	Methylene
1.57 (bp)	1.58 (bp)	CH2- CH2–COO	All acyl chains
2.01 (m)	2.01 (m)	CH2-CH=CH	Allylic-all unsaturated fatty acids
2.28 (t)	2.28 (t)	CH2–COO	All acyl chains
2.74 (t)	2.74 (t)	C=C-CH2C=C	Bis-allylic methylene (di-unsaturated fatty acid)
4.14–4.25 (dd)	4.13 – 4.25 (dd)	CH2O(ω1,3)	Glycerol (triacylglycerols)
5.24 (m)	5.23 (m)	CHO (ω2)	Glycerol (triacylglycerols)
5.31(m)	5.31(m)	CH=CH	Olefinic (all unsaturated fatty acid)

bp: broad peak; dd: double doublet; m: multiplet; t: triplet.

Figure 3. The ¹H NMR spectra of unroasted and roasted crude sesame seed oil at 400 MHz in CDCl₃; A: ¹H NMR spectrum of crude unroasted sesame oil, B: ¹H NMR spectrum of crude roasted sesame oil.

Table 4. ¹³C NMR assignments of unroasted and roasted crude Sesame oil at 100 MHz in CDCl₃. Two signals for the same olefinic environment indicate an equivalent resonance between two different olefinic carbons. Two signals for the same environment are splits in the triacylglycerol signal between the sn-1,3 or sn-2 fatty acid chains.

Chemical shifts (ppm) of unroasted Sesame seeds oil	Chemical shifts (ppm) of roasted Sesame seeds oil	Carbon	Assignment
14.27	14.28	C18 (CH3)	All acyl chains
22.75	22.75	C17 (CH2)	All acyl chains
25.01	25.01	C3	All acyl chains
25.85	25.79	C11	Diallylic
27.37	27.37	C8–1(oleyl) C8–14 (linoleyl)	Allylic
29.50–29.88	29.29–29.89	CH2n	All acyl chains
31.70	31.70	ω6	n-9, n-6
32.09	32.09	α-C2	All acyl chains
34.19	34.18	β-C2	All acyl chains
62.26	62.25	α-CH2O	Glycerol (triacylglycerols)
69.07	69.05	β–CH2O	Glycerol (triacylglycerols)
127.79	127.83	C15	Linolenyl
127.92	127.90	C10	Linolenyl
128.07	128.05	C12	Linoleyl
128.24	128.22	C10	Linoleyl
128.79	128.43	C12	Linolenyl
128.84	128.49	C13	Linolenyl
129.83	129.85	C9	Olelyl
129.98	130.10	C9	Linoleyl
130.16	130.15	C10	Olelyl
130.55	130.34	C13	Linoleyl
130.27	130.28	C9	Linolenyl
131.82	131.82	C16	Linolenyl
174.34	172.96	sn 1,3 C1	Carbonyl (triacylglycerols)
174.38	173.37	sn 2 C1	Carbonyl (triacylglycerols)

Figure 4. ¹³C NMR spectra of unroasted and roasted crude sesame oil at 100 MHz in CDCl₃; A: ¹³C NMR spectrum of unroasted crude sesame oil, B: ¹³C NMR spectrum of roasted crude sesame oil, showing the ¹³C assignment in Table 4.

Figure 5. The olefinic region 127–132 ppm of 100 MHz ¹³C NMR spectra of crude sesame oil; A: ¹³C NMR spectrum of olefinic region of crude unroasted sesame seeds oil, B: ¹³C NMR spectrum the olefinic region of crude roasted sesame seeds oil.

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