Integrating widely targeted metabolomics and network pharmacology to provide insights into the mechanism of nutrition changes in walnut kernel under different drying methods

The effect of drying temperature on nutritional metabolite profiles and health benefits in pellicle-free walnut kernels (WKs) remains unclear. This work used widely-targeted metabolomics to identify 1888 metabolites in WKs following three different drying methods. Among these, 697 temperature-sensitive metabolites (TSMs) were identified as key differential nutrition changes induced by drying temperature. Walnut kernels dried by hot-air drying with 80 °C (HD) had much higher antioxidant activity (around 155 %) than the other two drying methods. Based on WGCNA analysis, 249 significantly upregulated antioxidant contribution metabolites (ACMs) were identified as the primary contributors to the improved performance. Network pharmacology further revealed that these metabolites exhibit strong regulatory capabilities against neurological diseases, cardiovascular diseases, and cancer, providing optimal health benefits. A metabolic pathway network was constructed to provide insights into the potential mechanisms underlying the drying process in WKs. This work provides a theoretical basis for enhancing the quality of WKs.