Staff Members of the Institute of Biochemistry, TU - Institut für ...

Figure 1. MS2 of dimeric of furfuryl alcohol in ion tap analysis.
Green coffee does not contain any furfuryl alcohol. However, furfuryl alcohol is formed
during roasting. After 3 min of roasting at 210 °C the formation of furfuryl alcohol starts with
a significant increase during continued roasting and reduced at 5 min roasting. This means
that a degradation of the 1,2-enediol (key intermediate in the isomerization reaction of
fructose and glucose) and the degradation of quinic acid could occur. Furfuryl alcohol
oligomers are also found after 3 min of roasting and are also reduced after 5 min of roasting.
The oligomers that were identified with LC-MS is the dimer and acid condition also occur
during coffee roasting. The dimer is present because during degradation a 1,2-enediol also
form acid condition by producing formic acid. Therefore, furfuryl alcohol is able to
polymerize under that conditions and contribute in the formation of brown color.
Master Thesis completed
Tajana Golukova: Formation of potentially toxic furan derivatives in foods
During processing and especially roasting of food, many substances are formed by the
Maillard reaction and caramelization. Many of the formed substances contribute to the flavor,
but some of them can be harmful like HMF (5-hydroxymethylfurfural), HMFA (5hydroxymethyl-2-furoic
acid), furfural and FA (furfuryl alcohol). In the present work HPLC
methods for the determination of these substances were established, optimized, and afterwards
adapted to the analyses of food. Coffee is well known for its high content of Maillard
Reaction Products (MRPs) and also for the high content of furan derivatives. Therefore a
focus was laid on coffee and the development of HMF, furfural and FA during the roasting
process at 210 °C. Another aim was to find the precursors of HMFA in coffee with the
purpose to explain the high concentration in roasted coffee. Furfural was derivatized with
DNPH (2,4-dinitrophenylhydrazine) to get a better selectivity. Furfural was only found in
small quantities in filter coffee (6,36 µg/g) and balsamic vinegar (below the LQ). High
contents of furfuryl alcohol were observed in filter coffee (1430 µg/g) and instant coffee (267
µg/g). Furthermore a low concentration was found in pineapple juice (3,28 µg/g). HMF was
detected in plum juice (5,98 µg/g), coffee substitute (38,4 µg/g), balsamic vinegar (59,1
µg/mL), caramel-syrup (33,9 µg/mL), filter coffee (187 µg/g) and instant coffee (869 µg/g).
The roasting profile shows that the maximum concentrations of HMF (152 µg/g) and furfural
(3,51 µg/g) occur after 2 minutes. In contrast the highest concentration of furfuryl alcohol
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