Front Nutr. 2026 Aug 3;13:1853929. doi: 10.3389/fnut.2026.1853929. eCollection 2026.
ABSTRACT
INTRODUCTION: Olive, walnut, flaxseed, and camellia oils are premium edible oils rich in unsaturated fatty acids, yet they exhibit distinct fatty acid profiles: olive and camellia oils are high in monounsaturated fatty acids, while walnut and flaxseed oils are abundant in polyunsaturated fatty acids. Despite their market value and nutritional importance, a systematic comparative metabolomic analysis covering both volatile and non‑volatile compounds under unified conditions has been lacking.
METHODS: We performed a comprehensive metabolomic comparison of the four oils using headspace solid‑phase microextraction/gas chromatography‑mass spectrometry (HS‑SPME/GC‑MS) for volatile compounds and ultra‑high‑performance liquid chromatography‑high‑resolution mass spectrometry (UHPLC‑HRMS) for non‑volatile metabolites. Multivariate statistical methods, including principal component analysis (PCA), partial least‑squares discriminant analysis (PLS‑DA), and relative odor activity value (ROAV) calculation, were applied to identify differential metabolites and characteristic biomarkers.
RESULTS: A total of 100 volatile and 1,186 non‑volatile metabolites were identified, covering alcohols, aldehydes, fatty acids, terpenes, phenolics, and others. PCA and heatmap analyses showed clear separation among the four oils. Common flavor markers included hexanal, ethanol, and ethyl hexanoate, while specific biomarkers such as hydroxytyrosol (olive oil), juglone (walnut oil), lignans (flaxseed oil), and camelliasaponin (camellia oil) were distinguished. ROAV analysis highlighted key flavor‑active volatiles, and differential metabolites were significantly correlated with flavor attributes, oxidative stability, and nutritional characteristics.
DISCUSSION: Our integrated volatile‑non‑volatile metabolomic approach provides a systematic foundation for comparing the compositional, flavor, and quality differences among high‑unsaturated fatty acid vegetable oils. The identified biomarkers and their correlations offer valuable tools for oil authentication, quality control, and functional product development, demonstrating the superiority of combined metabolomic profiling over single‑platform analyses.
PMID:42609451 | PMC:PMC13478218 | DOI:10.3389/fnut.2026.1853929
