Comprehensive Two-Dimensional Gas Chromatography with a TOF MS Detector-An Effective Tool to Trace the Signature of...

Area of Science:

• Food Chemistry
• Analytical Chemistry
• Viticulture

Background:

• Grape varietal volatile compounds are key to wine aroma and flavor.
• Understanding these compounds aids in grape quality assessment and wine production.

Purpose of the Study:

• To develop and optimize a methodology for analyzing free volatile compounds in red grape varieties.
• To characterize the volatile profiles of Trincadeira, Cabernet Sauvignon, Syrah, Castelão, and Tinta Barroca grapes from different harvests.

Main Methods:

• Headspace solid-phase microextraction coupled with gas chromatography-gas chromatography-time-of-flight mass spectrometry (HS-SPME-GC × GC-TOFMS).
• Optimization of sample preparation (grape amount, NaCl, H2O) and extraction conditions (time, temperature, fiber type).

Main Results:

• Identified 52 free volatile compounds: 17 monoterpenes, 28 sesquiterpenes, and 7 C13-norisoprenoids.
• More volatile compounds were identified in the 2021 harvest compared to 2022.
• Linear discriminant analysis (LDA) revealed significant differences in volatile profiles among grape varieties and harvest years.

Conclusions:

• The optimized HS-SPME-GC × GC-TOFMS methodology effectively characterizes varietal volatile compounds in grapes.
• Grape variety and harvest year significantly influence the volatile profile, impacting varietal signature.