. 2021 Mar 10;8:647354. doi: 10.3389/fnut.2021.647354

Table 2.

Volatile compounds of unroasted and roasted pumpkin seeds.

Name	Peak area ratio (%)
	Raw pumpkin seed	120^°C	160^°C	200^°C
Heterocycles
Pyrazine	–	0.11 ± 0.01^b	0.41 ± 0.05^b	0.58 ± 0.52^a
2-Methylpyrazine	–	0.38 ± 0.33^c	1.27 ± 0.30^b	17.68 ± 0.14^a
2-Ethylpyrazine	–	–	–	0.93 ± 0.08
2,5-Dimethylpyrazine	4.23 ± 3.80^c	–	8.39 ± 0.38^b	17.13 ± 0.61^a
2,6-Dimethylpyrazine	–	–	0.15 ± 0.13^b	3.25 ± 0.05^a
2,3-Dimethylpyrazine	0.18 ± 0.03^b	–	0.09 ± 0.00^c	0.79 ± 0.02^a
2-Ethyl-5-methylpyrazine	–	–	0.90 ± 0.04^b	3.48 ± 0.25^a
3-Ethyl-2,5-dimethylpyrazine	–	–	0.28 ± 0.01^b	1.48 ± 0.09^a
2,3,5-Trimethylpyrazine	–	–	1.06 ± 0.06^b	3.85 ± 0.20^a
Pyridine	–	0.03 ± 0.02^c	0.15 ± 0.01^b	1.35 ± 0.09^a
2-Acetylpyrrole	–	0.01 ± 0.00^c	0.03 ± 0.01^b	0.13 ± 0.02^a
2-Pentylfuran	–	0.57 ± 0.29^a	0.59 ± 0.02^a	0.39 ± 0.28^a
2-Acetylfuran	–	–	0.03 ± 0.00^b	0.80 ± 0.04^a
5-Methyl furfural	–	–	–	0.35 ± 0.41
Furfural	–	0.01 ± 0.00^b	0.17 ± 0.16^b	1.96 ± 0.33^a
2-Methylthiazole	–	0.01 ± 0.00^b	0.01 ± 0.00^b	0.17 ± 0.01^a
Alcohols
2,3-Butanediol	7.98 ± 00.59^b	11.13 ± 1.36^a	8.90 ± 0.40^b	2.33 ± 0.13^c
Methyl mercaptan	–	0.53 ± 0.20^a	0.33 ± 0.67^a	0.27 ± 0.14^b
n-Hexanol	–	14.72 ± 1.74^a	7.12 ± 0.68^b	0.85 ± 0.07^c
3-Methyl-1-butanol	–	2.16 ± 0.62^a	1.00 ± 0.03^b	0.17 ± 0.01^c
Benzyl alcohol	0.34 ± 0.26^a	0.22 ± 0.33^b	0.07 ± 0.00^c	–
Acids
2-Methylbutyric acid	0.34 ± 0.01^c	0.41 ± 0.04^b	1.02 ± 0.04^a	–
Acetic acid	1.86 ± 0.39^a	2.40 ± 0.90^a	1.80 ± 0.18^a	1.11 ± 0.96^a
Ketones
2-Heptanone	–	0.04 ± 0.03^c	1.27 ± 0.03^b	17.68 ± 0.15^a
Acetylacetone	–	–	0.31 ± 0.02^b	1.24 ± 0.06^a
1-Hydroxy-2-propanone	–	0.07 ± 0.04^c	0.55 ± 0.08^a	0.26 ± 0.02^b
2,3-Pentanedione	–	–	0.24 ± 0.01^a	0.18 ± 0.02^b
Aldehyde
hexanal	–	0.13 ± 0.07^c	3.30 ± 0.28^a	0.69 ± 0.07^b
benzaldehyde	0.39 ± 0.07^b	0.17 ± 0.03^c	0.68 ± 0.04^a	0.20 ± 0.02^c

Values with similar superscripts in a column do not differ significantly (P < 0.05). –, not detected.