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. 2024 Nov 18;12(12):10576–10591. doi: 10.1002/fsn3.4590

TABLE 3.

Different compounds formed at 75°C, 70°C and 65°C (convective hot air drying).

(A) Compounds Class Reaction pathways Retention time (min) Fresh grapes Analytes (ng/g) at temperature (75°C) and drying time (h)
1 h 3 h 5 h 7 h 9 h 11 h 13 h 15 h
Hexanal Aldehyde LO 5.72 nd 0.21 1.08 nd nd nd nd nd nd nd
Heptanal Aldehyde LO, UFAO 10.314 nd 0.98 2.01 1.02 nd nd nd nd nd nd
Pentanal Aldehyde LO 3.01 nd nd nd nd 0.89 nd nd nd nd nd
Nonanal Aldehyde UFAO 13.99 0.43 0.53 0.78 0.54 1.23 0.45 0.25 2.13 0.56 0.89
Furan Furan MR, CR, AA, LO 1.56 nd nd nd nd nd nd 1.59 2.03 3.72 4.92
Furfural Furan MR, CR 7.86 nd nd nd nd nd 0.78 1.02 4.32 5.09 6.93
Furan 2‐ethyl‐5 methyl Furan MR, CR, AA 10.92 nd nd nd nd nd nd nd nd 1.14 3.02
Furan 2‐Propyl Furan LO, MR 5.34 nd nd nd nd nd nd nd nd nd 0.96
3‐Furaldehyde Furan MR, CR 7.34 nd nd nd nd nd nd nd 0.52 1.34 2.09
5‐Hydroxymethylfurfural Furan MR, CR of 3‐DG 15.25 nd nd nd nd nd nd nd nd nd 4.98
1‐pentanone 2‐furanyl Furan MR 10.87 nd nd nd nd nd nd nd nd 0.34 1.02
2‐Pentylfuran Furan LO, LO and AA interaction 12.51 nd nd nd nd nd nd nd nd nd 5.98
(B) Compounds Class Reaction pathways Retention time (min) Fresh grapes Drying time (h) and temperature (70°C)
Hexanal Aldehyde LO 5.72 nd 0.21 1.08 nd nd nd nd nd nd nd nd
Heptanal Aldehyde LO, UFAO 10.314 nd 0.98 2.01 1.02 nd nd nd nd nd nd nd
Nonanal Aldehyde UFAO 13.99 0.43 0.53 0.56 0.34 1.01 0.45 0.25 2.21 nd nd nd
Furan Furan MR, CR, AA, LO 1.56 nd nd nd nd nd nd nd 1.06 2.34 2.04 2.28
2‐Furancarboxaldehyde (Furfural) Furan MR, CR 7.86 nd nd nd nd nd nd nd nd 1.23 2.89 4.28
Furan 2‐ethyl‐5 methyl Furan MR, CR, AA 10.92 nd nd nd nd nd nd nd nd 0.14 2.12 2.32
Furan 2‐Propyl Furan LO, MR 5.34 nd nd nd nd nd nd nd nd nd nd 0.69
5‐Hydroxymethylfurfural Furan MR, CR of 3‐DG 15.25 nd nd nd nd nd nd nd nd nd 1.04 1.36
2‐Pentylfuran Furan LO, LO and AA interaction 12.51 nd nd nd nd nd nd nd nd 1.21 3.13 3.65
(C) Compounds Class Reaction pathways Retention time (min) Fresh grapes Drying time (h) and temperature (65°C)
Hexanal Aldehyde LO 5.72 nd 0.21 1.08 nd nd nd nd nd nd nd nd nd
Heptanal Aldehyde LO, UFAO 10.314 nd 0.48 1.01 1.02 nd nd nd nd nd nd nd nd
Nonanal Aldehyde UFAO 13.99 0.43 0.53 0.56 1.34 1.02 0.35 1.52 3.21 2.09 1.04 0.87 0.98
Furan Furan MR, CR, AA, LO 1.56 nd nd nd nd nd nd nd nd nd nd 1.98 0.96
2‐Furancarboxaldehyde (Furfural) Furan MR, CR 7.86 nd nd nd nd nd nd nd nd nd nd 1.48 2.98
Furan 2‐ethyl‐5 methyl Furan MR, CR, AA 10.92 nd nd nd nd nd nd nd nd nd nd nd 1.77
2‐Pentylfuran Furan LO, LO and AA interaction 12.51 nd nd nd nd nd nd nd nd nd nd 0.45 1.38

Note: All compounds measured in ng; nd = not detected at limit of detection.

Abbreviations: 3‐DG, 3‐deoxyglucoson; AA, Amino Acid; CR, Ceramelization; LO, Lipid oxidation; MR, Maillard Reaction; UFAO, unsaturated fatty acids oxidation.