New Anthocyanin-Human Salivary Protein Complexes

Area of Science:

• Food Chemistry
• Biochemistry
• Molecular Interactions

Background:

• Astringency, a sensory perception, is primarily caused by the interaction between phenolic compounds and salivary proteins.
• Understanding these interactions is crucial for determining the bioavailability of phenolic compounds.
• Anthocyanins are a class of phenolic compounds found in various fruits and vegetables.

Purpose of the Study:

• To investigate the molecular interactions between anthocyanins and human salivary proteins.
• To characterize the binding affinity and identify the resulting complexes.
• To elucidate the structural basis of astringency and influence on bioavailability.

Main Methods:

• Utilized mass spectrometry techniques, including MALDI-TOF-MS and FIA-ESI-MS, for protein and complex identification.
• Employed saturation-transfer difference (STD) NMR spectroscopy to study molecular interactions at the atomic level.
• Analyzed the dissociation constants (KD) of specific anthocyanin-protein complexes under varying pH conditions.

Main Results:

• Confirmed that anthocyanins interact with human salivary protein fractions.
• Quantified the dissociation constants for malvidin 3-glucoside with salivary proline-rich proteins at different pH values (1.92 mM at pH 3.4, 1.83 mM at pH 1.0).
• Successfully identified novel soluble complexes formed between salivary proteins and malvidin 3-glucoside.

Conclusions:

• Anthocyanin-salivary protein interactions are confirmed, providing molecular insights into astringency.
• The identified soluble complexes offer new understanding of how these compounds interact in the oral cavity.
• This research contributes to the knowledge of phenolic compound bioavailability and sensory perception.