Geographical Discrimination of Hulless Barley Based on Quality Traits, Volatiles, and Metabolomic Profiling Combined with Chemometrics

The geographical traceability of food products is crucial for quality assurance and consumer confidence. The chemical profile and taste quality of hulless barley vary considerably across different production areas, making the determination of its geographical origin and the identification of relevant geographical biomarkers essential. In this study, the quality traits, volatile compounds, and metabolites of 20 hulless barley cultivars from four primary producing areas were investigated. Multivariate analysis showed that there were significant differences in hulless barley from different regions (p < 0.05). The orthogonal partial least squares discriminant analysis (OPLS-DA) models exhibited good performance in terms of origin discrimination, identifying 27 volatiles and 86 metabolites that could be used as candidate markers for separation. Redundancy analysis (RDA) and correlation matrix analysis revealed that numerous candidate markers were closely related to soil chemical and climate parameters. The results demonstrate that quality traits, volatile compounds, and metabolites can be used to effectively distinguish the geographical origins of hulless barley, thereby confirming that there is a robust link between metabolite expression and environmental factors. This work highlights that chemical profiling, combined with chemometric techniques (the application of statistical and mathematical methods to chemical data), provides a valuable tool for the geographical discrimination of hulless barley.