Compositional markers for assessing avocado oil authenticity: fatty acids, sterols, triterpene dialcohols and waxes

The growing demand for refined and cold-pressed avocado oil raises concerns about adulteration and the adequacy of available authenticity criteria. This study evaluated conventional and complementary compositional parameters in five oils: three reference avocado oils — a cold-pressed oil (O) and two laboratory-extracted oils, one from pulp alone (P) and one from pulp with peel (PB) — and two commercial samples declared by the supplier as refined avocado oil (R) and a blend of refined and virgin avocado oil (RB). R and RB had lower palmitoleic and higher stearic acid proportions than the reference oils, outside the Codex ranges. Trans fatty acid isomers were detected only in R and RB, consistent with their declared refined oil content. R and RB showed higher relative proportions of stigmasterol (1.79–2.16%) and Δ7-stigmastenol (0.67–0.86%), than those observed in the reference avocado oils (0.28–0.36% and 0.05–0.09%, respectively). Erythrodiol and uvaol were not detected in O, P or PB, whereas their combined concentrations were 13.29 mg/kg in R and 10.33 mg/kg in RB. Similarly, total C40–C46 waxes was higher in R and RB (1441.22–1850.89 mg/kg) than in the reference oils (43.00–68.82 mg/kg). These differences, despite R and RB being declared as refined, may be compatible with the presence of an undeclared oil fraction, although its possible origin cannot be determined from the present results. The findings highlight triterpene dialcohols and waxes as promising complementary markers of avocado oil authenticity, warranting further investigation in a larger and representative set of authentic samples.