Spatial metabolomics and feature-based molecular networking to unveiling in-situ quality markers landscape and reflecting geographic origins of pomegranate seeds

Pomegranate seeds, a by-product of pomegranate processing, are gaining attention in food industries due to their high antioxidant activity. However, the lack of quality markers reflecting activity and spatial characteristics limits their utilization and product stability. In this research, a selective and sensitive method integrating ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry with feature-based molecular networking, and desorption electrospray ionization-mass spectrometry imaging developed to identify components and locate in-situ images of quality markers via spatial metabolomics analysis. Additionally, molecular docking analyses and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays validated the antioxidant quality markers and elucidated correlations between these markers, regions, and activity. A total of 227 components were identified, and six were selected as quality markers for pomegranate seeds, reflecting their antioxidant activity and spatial characteristics. Consequently, this research provides an efficient method for screening food quality markers based on activity and spatial characteristics, providing insights into food quality evaluation.