Analysis of the dynamic metabolic changes during the ripening of wolfberry (Lycium barbarum L.) fruits by theta-nano-extractive electrospray ionization mass spectrometry

Metabolic changes during the ripening of wolfberry (<i>Lycium barbarum</i> L.) fruits reflect their quality and pharmacological properties. To decipher the metabolic evolution underlying this physiological process, a systematic analysis of wolfberry fruits at different ripening stages (7-35 days after anthesis) was conducted by theta-nano-extractive electrospray ionization mass spectrometry. Multivariate analysis effectively discriminated the various stages and identified proline, γ-aminobutyric acid, arginine, and <i>N</i> ¹-caffeoyl-<i>N</i> ¹⁰-dihydrocaffeoyl spermidine as potential differential metabolites. Polyamine and flavonoid metabolism were significantly activated during the early ripening stages, leading to the rapid accumulation of antioxidant components such as spermidine, rutin, and chlorogenic acid. In the late ripening stages, amino acid metabolism was markedly enhanced, resulting in a substantial increase in betaine, serine, and threonine. This study elucidates the key stages and metabolic foundation of quality formation in wolfberry fruits at the metabolomic level, providing a theoretical basis for determining the optimal harvest time and regulating nutritional quality.