Discrimination of roast and ground coffee aroma

Table 1 Key aroma compounds, chemical structure, predicted log P and K a/w and literature odour threshold (above an aqueous solution)

Compound	Log P	K_a/w	Odour threshold
E, E-2, 4-Decadienal	3.33	0.008994	0.07 ppb[23]
25152-84-5
2,3-Pentanedione	−0.85	1.07E-05	20 ppb[24]
600-14-6
2-Acetylpyrazine	−0.38	2.17E-07	62 ppb[23]
22047-25-2
2-Acetylpyridine 1122-62-9	n/a	n/a	n/a
2-Ethyl-3,6-dimethylpyrazine	n/a	n/a	8.6 ppb[23]
13360-65-1
2-Methylbutanal	1.23	0.0065	0.9 ppb[23]
96-17-3
3-Methylbutanal	1.23	0.0065	0.17 ppb[23]
590-86-3
2-Methylbutanoic acid	n/a	n/a	740 ppb[25]
1169-53-0
3-Methylbutanoic acid	1.49	5.23E-05	540 ppb[25]
503-74-2
Furfural	0.83	0.000548	3000 ppb[24]
98-01-1
Furfurylmethylsulphide	n/a	n/a	n/a
1438-91-1
Guaiacol	1.34	1.36E-06	3 ppb[23]
90-05-1
Maltol	−0.19	0.000267	20 ppm[23]
118-71-8
Phenylacetaldehyde	1.54	0.000224	4 ppb[24]
122-78-1
Trimethylpyrazine	1.58	0.00016	9 ppm[23]
14667-55-1

ISSN: 2044-7248