Combined Untargeted and Targeted Fingerprinting by Comprehensive Two-Dimensional Gas Chromatography to Track Compositional Changes on Hazelnut Primary Metabolome during Roasting

This study focuses on the detectable metabolome of high-quality raw hazelnuts (Corylus avellana L.) and its changes after dry-roasting. Informative fingerprinting was obtained by comprehensive two-dimensional gas chromatography with fast-scanning quadrupole mass spectrometry (GC×GC-qMS) combined dedicated data processing. In particular, untargeted targeted (UT) fingerprinting, based pattern recognition template matching, is applied to chromatograms from roasted samples Tonda Gentile Trilobata Anakliuri harvested in Italy Georgia. Lab-scale roasting designed develop a desirable organoleptic profile matching industrial standards. Results, 430 peak features, reveal that phenotype expression markedly correlated cultivar pedoclimatic conditions. Discriminant components between cultivars are amino acids (valine, alanine, glycine, proline); organic (citric, aspartic, malic, gluconic, threonic, 4-aminobutanoic acids); sugars polyols (maltose, xylulose, xylitol, turanose, mannitol, scyllo-inositol, pinitol). Of these, proline have high informational role as precursors 2-acetyl- 2-propionylpyrroline, two key-aroma compounds hazelnuts. Roasting has decisive impact metabolite patterns—it caused marked decrease (−90%) proline, leucine valine, aspartic pyroglutamic acid −50% reduction saccharose galactose.