. 2022 Jan 10;31(2):211–220. doi: 10.1007/s10068-021-01023-6

Table 1.

Volatile compounds in raw and roasted red pepper seeds

No	RI¹	Volatile compounds	Aroma description²	Relative peak areas (mean ± SD)³			ID⁵
No	RI¹	Volatile compounds	Aroma description²	Raw	Roasted at 100 °C	Roasted at 200 °C	ID⁵
Pyrazines (8)
1	820	2-methylpyrazine	Nutty, roasted, chocolate, toasted	ND^b4	ND^b	1.689 ± 0.343^a	MS/RI⁵
2	914	2,5-dimethylpyrazine	Chocolate, roasted, nutty	ND^b	ND^b	10.517 ± 2.018^a	MS/RI
3	999	2-ethyl-6-methylpyrazine	Toasted, hazelnut-like	ND^b	ND^b	0.839 ± 0.169^a	MS/RI
4	1001	2-ethyl-5-methylpyrazine	Nutty, roasted	ND^b	ND^b	1.550 ± 0.266^a	MS/RI
5	1002	2,3,5-trimethylpyrazine	Roasted, potato-like	ND^b	ND^b	1.905 ± 0.383^a	MS/RI
6	1077	3-ethyl-2,5-dimethylpyrazine	Roasted	ND^c	2.877 ± 0.257^b	4.224 ± 0.805^a	MS/RI
7	1086	2,3,5,6-tetramethylpyrazine		ND^c	2.078 ± 0.392^b	6.977 ± 1.148^a	MS/RI
8	1176	2-methoxy-3-(2-methylpropyl)pyrazine (2-Isobutyl-3-methoxypyrazine)	Green bell-pepper note, green, earthy	ND^b	0.030 ± 0.004^a	ND^b	MS/RI
		Sum of pyrazines		0.000	4.985	27.700
Pyrroles (4)
9	< 800	1-methylpyrrole	Sweet, woody-herbaceous, coffee	ND^c	0.064 ± 0.004^b	0.306 ± 0.016^a	MS/RI
10	< 800	1H-pyrrole	Slightly pungent, sweet, green, toasted	ND^b	ND^b	0.115 ± 0.023^a	MS/RI
11	841	2-methyl-1H-pyrrole		ND^b	ND^b	0.085 ± 0.011^a	MS/RI
12	1067	1-(1H-pyrrol-2-yl)-ethanone (2-acetylpyrrole)	Bread, cracker, popcorn-like	0.248 ± 0.032^c	0.751 ± 0.148^b	2.007 ± 0.292^a	MS/RI
		Sum of pyrroles		0.248	0.815	2.514
Oxygen-containing heterocyclic compounds (9)
13	830	furan-2-carbaldehyde (furfural)	Sweet, bread-like, caramel-like	ND^b	ND^b	0.596 ± 0.122^a	MS/RI
14	883	cyclopent-4-ene-1,3-dione		ND^b	ND^b	0.278 ± 0.028^a	MS/RI
15	902	1-(furan-2-yl)ethanone (2-acetylfuran)	Floral, balsamic-cinnamic, roasted	ND^b	0.066 ± 0.003^a	ND^b	MS/RI
16	912	oxolan-2-one (γ-butyrolactone)	Sweet, slightly buttery	0.166 ± 0.008^c	0.619 ± 0.078^b	1.704 ± 0.345^a	MS/RI
17	934	cyclohex-2-en-1-one		1.248 ± 0.246^b	1.416 ± 0.288^b	2.467 ± 0.076^a	MS/RI
18	977	2,4-dihydroxy-2,5-dimethylfuran-3-one		ND^b	ND^b	0.717 ± 0.039^a	MS
19	989	2-pentylfuran	Fruity	0.099 ± 0.015^b	0.132 ± 0.018^b	0.598 ± 0.070^a	MS/RI
20	1111	3-hydroxy-2-methylpyran-4-one (maltol)	Caramel-like	0.385 ± 0.078^a	0.025 ± 0.004^b	ND^b	MS/RI
21	1139	3,5-dihydroxy-6-methyl-2,3-dihydropyran-4-one (hydroxydihydromaltol)		0.082 ± 0.003^b	0.428 ± 0.085^b	20.838 ± 4.077^a	MS/RI
		Sum of oxygen-containing heterocyclic compounds		1.980	2.685	27.198
Aldehydes (6)
22	886	(Z)-2-ethenylbut-2-enal		0.320 ± 0.058^b	0.354 ± 0.041^b	0.599 ± 0.044^a	MS
23	905	3-methylsulfanylpropanal (methional)	Cooked potato-like	ND^b	ND^b	0.760 ± 0.025^a	MS/RI
24	957	benzaldehyde	Sweet, almond-like	ND^b	ND^b	0.140 ± 0.016^a	MS/RI
25	1038	hexanedial		ND^b	0.238 ± 0.037^a	ND^b	MS
26	1043	2-phenylacetaldehyde (benzeneacetaldehyde)	Sweet, floral	ND^b	0.115 ± 0.015^b	8.984 ± 1.007^a	MS/RI
27	1313	(2E,4E)-deca-2,4-dienal		ND^b	ND^b	0.207 ± 0.037^a	MS/RI
		Sum of aldehydes		0.320	0.706	10.690
Ketones (3)
28	< 800	1-hydroxybutan-2-one	Toasted	ND^b	ND^b	0.057 ± 0.001^a	MS
29	938	(Z)-hept-3-en-2-one		ND^b	ND^b	0.234 ± 0.027^a	MS/RI
30	1185	1-(3,4-dihydro-2H-pyridin-1-yl)ethanone		ND^b	ND^b	0.413 ± 0.084^a	MS
		Sum of ketones		0.000	0.000	0.704
Alcohols (13)
31	< 800	3-methylbutan-1-ol (isopentyl alcohol)		0.082 ± 0.006 ^b	0.076 ± 0.002^b	0.155 ± 0.028^a	MS/RI
32	801	butane-2,3-diol	Creamy	ND^c	6.627 ± 0.676^b	8.388 ± 0.708^a	MS/RI
33	838	4-methylpentan-1-ol		ND^b	ND^b	0.151 ± 0.011^a	MS/RI
34	860	furan-2-ylmethanol (furfuryl alcohol)	burnt	0.067 ± 0.010^b	0.171 ± 0.015^b	1.307 ± 0.200^a	MS/RI
35	871	hexan-1-ol	Fruity, herbal	0.181 ± 0.006^b	0.117 ± 0.006^b	0.476 ± 0.097^a	MS/RI
36	885	(5-methylfuran-2-yl)methanol	Caramel-like	ND^b	ND^b	0.507 ± 0.044^a	MS
37	980	oct-1-en-3-ol	Mushroom-like	0.044 ± 0.005^c	0.073 ± 0.004^b	0.191 ± 0.004^a	MS/RI
38	1019	2-chlorocyclohexan-1-ol		0.758 ± 0.154^a	0.483 ± 0.092^b	ND^c	MS/RI
39	1038	phenylmethanol		0.258 ± 0.004^a	ND^b	ND^b	MS/RI
40	1088	2-methoxyphenol (o-guaiacol)		ND^b	ND^b	0.296 ± 0.019^a	MS/RI
41	1113	2-phenylethanol	Sweet, floral	0.663 ± 0.107^a	0.274 ± 0.029^b	ND^c	MS/RI
42	1314	4-ethenyl-2-methoxyphenol (4-vinylguaiacol)	Woody	ND^b	ND^b	4.273 ± 0.801^a	MS/RI
43	1654	(1S,4R)-1,6-dimethyl-4-propan-2-yl-3,4,4a,7,8,8a-hexahydro-2H-naphthalen-1-ol (α-cadinol)		0.470 ± 0.086^b	0.497 ± 0.098^b	0.739 ± 0.110^a	MS/RI
		Sum of alcohols		2.523	8.319	16.483
Acid and Esters (4)
44	921	2-ethylbutanoic acid		1.054 ± 0.065^a	ND^b	ND^b	MS/RI
45	1189	methyl 2-hydroxybenzoate		0.966 ± 0.191^b	0.703 ± 0.122^b	1.833 ± 0.145^a	MS/RI
46	1370	2-(2-butoxyethoxy)ethyl acetate		1.766 ± 0.340^b	2.861 ± 0.586^b	4.325 ± 0.757^a	MS
47	1595	[2,2,4-trimethyl-3-(2-methylpropanoyloxy)pentyl] 2-methylpropanoate		0.092 ± 0.015^b	0.066 ± 0.005^b	0.139 ± 0.026^a	MS
		Sum of acid and esters		3.878	3.629	6.297
		Sulfur-containing compounds (2)
48	893	methylsulfinylmethane (dimethyl sulfoxide)	Onion-like	1.345 ± 0.171^a	0.158 ± 0.022^b	0.108 ± 0.015^b	MS/RI
49	923	methylsulfonylmethane (dimethyl sulfone)		ND^b	0.095 ± 0.013^a	ND^b	MS/RI
		Sum of sulfur-containing compounds		1.345	0.254	0.108
Terpene hydrocarbons (2)
50	888	1,2-xylene (o-xylene)	Geranium, rubbery, spicy	3.100 ± 0.605^a	0.382 ± 0.060^c	1.272 ± 0.253^b	MS/RI
51	1047	(3E)-3,7-dimethylocta-1,3,6-triene (β-ocimene)	Warm herbaceous	1.426 ± 0.064^b	1.611 ± 0.279^b	3.370 ± 0.512^a	MS/RI
		Sum of terpene hydrocarbons		4.527	1.993	4.642

¹Retention indices were determined using n-alkanes C₈-C₂₂ as external standards on HP-5MS column

²Aroma description in previous reports (Lopes et al., 2021; Luning et al., 1994; Oh and Cho, 2021; Qin et al., 2011; Wang et al., 2020) was shown

³Average of contents compared to that of the internal standard mean ± standard deviation

⁴ND, not detected

⁵Identification was performed as follow: MS/RI, mass spectrum was consistent with that of Wiley mass spectrum database; MS, mass spectrum was consistent with that of Wiley mass spectrum database

⁶There are significant differences among samples having different letters in a row (p < 0.05)