Untargeted profiling and classification of maple syrup quality from the chromatographic and mass spectrometric analysis of volatile and nonvolatile chemical fractions

Abstract

Maple syrup production faces challenges from the “buddy flavor” defect (√R5), a sensory issue compromising syrup quality. This study employed a multimodal approach combining headspace solid-phase microextraction-gas chromatography–mass spectrometry (HS-SPME-GC/MS) and ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) combined with chemometrics to profile volatile and nonvolatile compounds associated with √R5 and regular (REG) maple syrup. HS-SPME-GC/MS identified key volatile markers, including pyrazines and sulfur-containing compounds such as dimethyl disulfide, many of which were previously unreported. UPLC-QTOF-MS/MS investigated nonpolar compounds and provided insights into nonvolatile chemical signatures underlying maple syrup quality. Chemometric and machine learning analyses classified syrup based on metabolite variations, with principal component analysis (PCA) models showing distinct clustering and PCA-support vector machine (PCA-SVM) achieving 93.8% classification accuracy. This study contributes to a comprehensive understanding of the √R5-associated chemical profiles and underscores the potential of our proposed analytical tools to improve quality assurance frameworks and identification of flavor-altering chemical changes.