Tracing oxidation reaction pathways in wine using ¹³C isotopolog patterns and a putative compound database

Area of Science:

• * Food Chemistry
• * Analytical Chemistry
• * Wine Chemistry

Background:

• * Quinones are reactive electrophilic compounds formed during wine oxidation.
• * These quinones significantly affect wine's color and flavor by reacting with nucleophiles.
• * Previous studies confirmed quinone reactions in model wines, but not in real wine matrices.

Purpose of the Study:

• * To identify and confirm quinone reaction products in real wine during oxidation.
• * To elucidate reaction pathways of quinones with wine components using stable isotope labeling.

Main Methods:

• * Utilized a stable isotope labeling approach with ¹³C₆ labeled ortho-quinone.
• * Employed high-performance liquid chromatography coupled to time-of-flight mass spectrometry (HPLC-TOF-MS).
• * Combined mass spectrometry data with an exact-mass list of putative products and M+6 mass isotope patterns.

Main Results:

• * Detected fourteen compounds resulting from quinone reactions in real wine.
• * Confirmed the presence of these compounds by matching exact masses and observing the M+6 isotope pattern from the labeled quinone.
• * Established reaction pathways for quinone formation and their subsequent reactions with wine catechols.

Conclusions:

• * Stable isotope labeling is an effective technique for identifying quinone reaction products in real wine.
• * The study identified novel compounds and elucidated reaction mechanisms impacting wine quality.
• * This analytical approach provides significant insight into wine oxidation processes.