Cis‐Vaccenic Acid as a Compositional Marker for Detecting High‐Oleic Seed Oil Adulteration in Avocado Oil

ABSTRACT

The rapid expansion of the global avocado oil market has intensified concerns about economic adulteration with lower‐cost, high‐oleic seed oils that resemble the fatty acid specifications of avocado oil. Cis‐vaccenic acid C18:1 ( n −7) occurs at higher proportions in avocado oil than in common seed oil adulterants, making it a promising complementary marker for avocado oil authenticity. However, natural compositional variability must be incorporated into threshold development to ensure reliable analytical classification of authentic oils. This study evaluates the analytical performance of cis‐vaccenic acid as a compositional marker for detecting high‐oleic seed oil adulteration in avocado oil using 298 authentic avocado oils representing 24 cultivars and 13 producing regions. Linear mixed‐effects modeling demonstrated that geographic origin accounted for 73.7% of total variability in cis‐vaccenic acid content, exceeding the contribution of cultivar (18.4%). A one‐sided tolerance interval ( α  = 0.05, p  = 0.99) established a statistically supported lower bound of 3.2%, encompassing 99.7% of authentic oils. Controlled blending experiments with common seed oil adulterants demonstrated linear decreases in cis‐vaccenic acid with increasing adulteration ( R ²  ≥ 0.99). Receiver operating characteristic analysis confirmed strong discriminatory capacity (AUC = 0.89) and identified a balanced operational threshold of 4.6%. These findings support the use of cis‐vaccenic acid as a complementary screening marker within the Codex framework for improving detection of high‐oleic seed oil adulteration in avocado oil.