Figures (3)  Tables (4)

    • Figure 1. 

      Coffee beans of (a) different roasted degree and (b) colour parameters.

    • Figure 2. 

      (a) Phenolics and (b) fatty acid profiles of different roasted coffee.

    • Figure 3. 

      Coffee olfactory detectable aroma profiles of different roasted coffee.

    • Correlation (r) TPC Chlorogenic acid Caffeic acid Palmitic acid Linoleic acid Oleic acid Stearic acid
      L* +0.8434 +0.9101 −0.9360 −0.7515 +0.5159 −0.9568 −0.5133
      TPC +0.9896 −0.6216 −0.9868 +0.8742 −0.9615 −0.8724
      Chlorogenic acid −0.7177 −0.9535 +0.7989 −0.991 −0.7968
      Caffeic acid +0.5078 −0.2693 +0.7989 +0.267

      Table 1. 

      Correlation between luminosity, phenolic, and fatty acid profiles.

    • No. Retention time (min) Compound D M L
      1 2.856 Acetic acid 3.91 7.49 9.77
      2 3.321 1-Hydroxy-2-propanone − − 2.69
      3 4.316 Pyrazine 0.43 − −
      4 4.518 Pyridine 7.01 2.73 −
      5 5.415 1-Methyl-1,2,3,6-tetrahydropyridine 0.56 − −
      6 5.825 Dihydro-2-methyl-3(2H)-furanone 0.74 1.11 1.25
      7 6.192 Methyl pyrazine 3.90 3.48 3.23
      8 6.473 Furfural 1.97 4.86 13.44
      9 6.94 3-Methylbutanoic acid − 0.48 1.71
      10 7.124 2-Furanmethanol 18.82 18.05 16.68
      11 7.413 1-Acetoxyacetone 3.75 3.27 1.52
      12 8.445 Furfuryl formate 0.94 0.89 0.51
      13 8.577 2,6-Dimethyl pyrazine 6.14 6.34 6.36
      14 8.67 2-Ethylpyrazine 2.55 1.36 −
      15 8.782 2,3-Dimethyl pyrazine 0.70 0.56 −
      16 9.856 2-Butyl furan 0.26 0.31 0.37
      17 9.904 3-Ethyl pyridine 0.58 − −
      18 10.147 5-Methylfurfural 3.43 8.45 10.48
      19 10.761 Phenol 0.32 − −
      20 11.094 Furfuryl acetate 8.62 6.09 3.33
      21 11.145 2-Ethyl-6-methyl pyrazine 1.63 1.71 1.91
      22 11.229 2-Ethyl-5-methylpyrazine − − 2.52
      23 11.335 2-Ethyl-3-methylpyrazine 0.63 0.74 0.65
      24 11.398 1-Methyl-1H-pyrrole-2-carbaldehyde 0.53 0.63 0.99
      25 11.838 1-Acetyl-1,4-dihydropyridine 1.25 0.94 0.94
      26 12.033 3-Methylcyclopentane-1,2-dione 0.61 0.53 -
      27 12.024 2-Hydroxy-3-methyl-2-cyclopenten-1-one − − 0.38
      28 12.436 3,4-Dimethyl-2,5-furandione 0.88 0.82 0.42
      29 12.574 Benzeneacetaldehyde − − 0.37
      30 12.958 2,5-Dimethylfuran-3,4(2H,5H)-dione − − 0.92
      31 13.113 2-Acetylpyrrole 1.06 1.05 0.43
      32 13.163 3-Pyridinol − − 0.34
      33 13.492 2-Acetyl-1-methylpyrrole 0.89 0.56 −
      34 13.604 3-Ethyl-2,5-dimethylpyrazine 1.77 1.99 2.44
      35 13.78 2-Furfurylfuran 1.44 0.94 −
      36 13.486 Furfuryl propionate 1.01 0.85 −
      37 13.958 2-Methoxyphenol 1.36 0.74 −
      38 14.042 3-Ethyl-2-hydroxy-2-cyclopenten-1-one − − 0.42
      39 14.608 Maltol 1.24 1.03 0.66
      40 14.812 2-Acetyl-3-methylpyrazine 0.91 1.03 1.08
      41 15.527 3,5-Dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one − − 0.56
      42 15.83 4-Hydroxymandelic acid − − 0.31
      43 15.951 3,5-Diethyl-2-methylpyrazine 0.71 0.67 −
      44 16.635 5-Methyl-2-furfuryl furan 0.57 0.28 0.24
      45 16.71 1-Furfurylpyrrole 0.89 0.80 0.54
      46 16.767 2-Acetyl-5-methylfuran − 0.52 0.63
      47 16.923 3-Methoxybenzenethiol − 0.38 0.65
      48 16.928 4-Methoxybenzenethiol 0.42 − −
      49 19.428 4-Ethyl-2-methoxyphenol 0.64 0.33 −
      50 20.029 Furfuryl ether 0.36 0.25 −
      51 20.384 2-Methoxy-4-vinylphenol 0.73 1.27 1.32
      52 20.642 Mercaptoethanol − − 0.32
      53 35.005 Hexadecanoic acid − − 1.08

      Table 2. 

      Volatile profiles of different roasted coffee.

    • No. Compound FEMA no. Aroma attribute
      1 Furans Dihydro-2-methyl-3(2H)-furanone 3373 Coffee furanone
      2 Furfural 2489 Sweet, almond, bready
      3 Furfuryl alcohol 2491 Burnt, caramelized, creamy, sugary
      4 Furfuryl formate 4542 Coffee
      5 2-Butyl furan 4081 Fruity, sweet
      6 5-Methylfurfural 2702 Caramelized, sweet, bready
      7 Furfuryl acetate 2490 Fruity, roast, sweet
      8 3,4-Dimethyl-2,5-furandione − Burnt, sweet, smoky
      9 5-Methyl-2-furfuryl furan Almond, caramelized, burnt sugar
      10 Pyrazines Methyl pyrazine 3309 Nutty, roasted, chocolate, coffee
      11 2,6-Dimethyl pyrazine 3273 Nutty, roast, cocoa, coffee, musty
      12 2-Ethyl-6-methyl pyrazine 3919 Roast, hazelnut
      13 2-Ethyl-3-methylpyrazine 3155 Roast, nutty
      14 3-Ethyl-2,5-dimethylpyrazine 3149 Hazelnut, fatty, coffee, chocolate
      15 2-Acetyl-3-methylpyrazine 3964 Roast, nutty, vegetable
      16 Misc. 1-Methyl-1H-pyrrole-2-carbaldehyde 4332 Burnt
      17 2-Acetylpyrrole 3202 Walnut, roast
      18 1-Furfurylpyrrole 3284 Waxy, fruity, coffee, vegetable
      19 Acetic acid 2006 Sharp vinegar
      20 1-Acetoxyacetone − Fruity, buttery, nutty
      21 1-Acetyl-1,4-dihydropyridine − Caramelized, creamy
      22 Maltol − Sweet, caramelized, candy, bready
      23 2-Methoxy-4-vinylphenol 2675 Smoky, balsamic, vanilla

      Table 3. 

      Aroma attributes of different roasted coffee.

    • No. Compound Correlation (r)
      1 Furans Dihydro-2-methyl-3(2H)-furanone 0.9322
      2 Furfural 0.9998
      3 Furfuryl alcohol −0.9894
      4 Furfuryl formate −0.9766
      5 2-Butyl furan 0.9561
      6 5-Methylfurfural 0.7671
      7 Furfuryl acetate −0.9442
      8 3,4-Dimethyl-2,5-furandione −0.9806
      9 5-Methyl-2-furfuryl furan −0.7875
      10 Pyrazines Methyl pyrazine −0.8419
      11 2,6-Dimethyl pyrazine 0.5803
      12 2-Ethyl-6-methyl pyrazine 0.9996
      13 2-Ethyl-3-methylpyrazine 0.0084
      14 3-Ethyl-2,5-dimethylpyrazine 0.9954
      15 2-Acetyl-3-methylpyrazine 0.7728
      16 Misc. 1-Methyl-1H-pyrrole-2-carbaldehyde 0.9973
      17 2-Acetylpyrrole −0.9406
      18 1-Furfurylpyrrole −0.9999
      19 Acetic acid 0.8548
      20 1-Acetoxyacetone −0.9971
      21 1-Acetyl-1,4-dihydropyridine −0.4983
      22 Maltol −0.9889
      23 2-Methoxy-4-vinylphenol 0.8582

      Table 4. 

      Correlation between luminosity and volatile profiles.