Fatty Acid Composition, Oxidative Stability, and Metabolomic Changes in Hickory Nut Oil During Accelerated Oxidation

This study systematically investigated the dynamic changes in fatty acid composition and oxidative stability of hickory nut oil during accelerated oxidation, and characterized the metabolic features associated with lipid oxidation using a metabolomics approach. Accelerated oxidation was conducted using the Schaal oven method. The results showed that the peroxide value (POV) and malondialdehyde (MDA) content reached maximum levels of 121.5 meq/kg and 1.94 μg/mL, while the conjugated diene value (CDV) and carbonyl value (COV) increased to 15.12 and 19.68 meq/kg, respectively. The fatty acid profile exhibited notable changes, with unsaturated fatty acids decreasing from 92.52% to 90.65% and saturated fatty acids increasing from 6.92% to 7.88%. A total of 2026 metabolites were identified, among which fatty acyls and benzenoids were predominant. The oxidation rate remained low during the initial phase (0-10 days) but increased markedly after approximately 25 days, leading to accelerated oxidation and a pronounced decline in oil quality. Pathway enrichment analysis further revealed that α-linolenic acid metabolism was the principal pathway associated with the oxidative process of hickory nut oil.