NMR-Based Studies on Odorant–Melanoidin Interactions in Coffee Beverages
Michael Gigl, Thomas Hofmann, Oliver Frank
Journal of Agricultural and Food Chemistry
Abstract
A quantitative <sup>1</sup>H NMR-based approach was established, which allowed the direct and noninvasive analysis of molecular interactions between key coffee odorants and high-molecular-weight (HMW) melanoidin polymers. A clear distinction between covalent and noncovalent interactions was achieved by monitoring the time dependency of odorant-polymer interactions, resulting in four scenarios: covalent, π-π, covalent and π-π-, as well as no interactions. Evaluation of temperature influence on e.g. 2-furfurylthiol (FFT), revealed an altered behavior with increased π-π stacking at lower temperatures and accelerated covalent interactions at higher temperatures. Human sensory experiments with HMW material and a coffee aroma reconstitution model showed a drastic reduction of "roasty/sulfury" aroma notes, as well as an increased "sweetish/caramel-like" flavor. The lack of interactions between the "sweetish/caramel" smelling 4-hydroxy-2,5-dimethyl-3(2<i>H</i>)-furanone with the HMW melanoidins in combination with the high binding affinity of coffee thiols explains the sensory evaluation and is obviously the reason for the fast disappearance of the typical "roasty/sulfury" aroma impressions of a freshly prepared coffee brew.
Extracted Claims
4 claims extracted from this paper into the knowledge graph
2-furfurylthiol (FFT) exhibits altered behavior with increased π-π stacking at lower temperatures and accelerated covalent interactions at higher temperatures
“Evaluation of temperature influence on e.g. 2-furfurylthiol (FFT), revealed an altered behavior with increased π-π stacking at lower temperatures and accelerated covalent interactions at higher temper...”
HMW melanoidins reduce roasty/sulfury aroma notes
“Human sensory experiments with HMW material and a coffee aroma reconstitution model showed a drastic reduction of 'roasty/sulfury' aroma notes”
4-hydroxy-2,5-dimethyl-3(2H)-furanone lacks interactions with HMW melanoidins
“The lack of interactions between the 'sweetish/caramel' smelling 4-hydroxy-2,5-dimethyl-3(2H)-furanone with the HMW melanoidins in combination with the high binding affinity of coffee thiols explains ...”