Fatty Acid Composition and Oxidative Changes in Pecan and Walnut Oils from Eastern Europe

Carya illinoinensis (pecan) has recently emerged as a promising oilseed crop in Eastern Europe; however, its oil has not been systematically characterized under regional growing conditions or directly compared with that of the established nut crop, Juglans regia (walnut). This study evaluated the proximate composition, fatty acid profile, and short-term oxidative stability of oils from six pooled sample groups, comprising three pecan and three walnut composite samples collected from Romania and the Republic of Moldova. Oils were extracted by hot pressing, kernel composition was determined using standard official (AOAC) methods, fatty acid composition was analyzed by gas chromatography-mass spectrometry (GC-MS), and oxidative stability was assessed by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) during 20 days of storage. Romanian pecan oils contained 67-68% total fat and were rich in linoleic acid (55-57%), whereas walnut oils contained 59-61% fat and were dominated by oleic acid (57-58%). The PNC composite sample exhibited an oleic acid-dominant profile that differed from those of the other two pecan samples. Because cultivar identity, genotype, and environmental variables were not determined, the cause of this difference cannot be established from the present study. All samples remained below the Codex Alimentarius PV limit (3.0 meq O₂/kg). TBARS changes differed among the analyzed composite oils; however, these differences cannot be attributed solely to fatty acid composition because antioxidant constituents were not measured. Oleic and linoleic acids were strongly and inversely correlated (Pearson r = -0.9998, p < 0.001). These findings provide the first comprehensive characterization of pecan oil produced under Eastern European conditions and demonstrate compositional variation among the analyzed composite samples, although the factors responsible for this variation could not be determined.