LC-MS/MS-Based Metabolomics Identifies 2-Aminopurine as a Predictive Freshness Biomarker in Goose Egg Yolk During Refrigerated Storage

Goose yolk, the primary source of nutrients and flavor, is particularly susceptible to quality deterioration during storage, yet its metabolic dynamics remain poorly characterized. To elucidate these changes, we combined physicochemical assays with untargeted LC-MS/MS metabolomics to systematically profile the temporal metabolic alterations in goose egg yolks stored at 4 °C for up to 60 days, using day-1 yolks as fresh controls. Our analysis quantified 1005 metabolites and identified a critical metabolic shift occurring after 30 days of storage. Among 21 significantly altered metabolites, the sustained decline of adenosine and 2-aminopurine, alongside the accumulation of 4-hydroxyretinoic acid, strongly correlated with the loss of egg freshness. Interaction network and pathway analyses pinpointed purine metabolism-with adenosine and 2-aminopurine as central nodes-as a core pathway impaired in yolk during storage. Crucially, we identify 2-aminopurine as a novel, storage-sensitive biomarker for goose egg freshness derived from yolk metabolomics, directly linking intracellular metabolic dysregulation to observable quality decline. This study deciphers the metabolic landscape of goose egg yolk aging and provides a targeted, mechanism-based strategy for yolk-centric quality monitoring and preservation, offering new insights for food composition analysis and safety assurance.