Unveiling Olive Oil Authenticity: A Comprehensive Study on Adulteration Detection through SPR-Enhanced Ellipsometry

The present work investigates the adulteration of extra virgin olive oil (EVOO) using highly surface-sensitive SPR-enhanced ellipsometry (SPRE) technique, aiming to ensure food quality and consumer safety. Due to the elevated cost of EVOO, adulteration with cheaper, poor-quality refined or edible oils has become a common practice for economic profit. The EVOO is purposely adulterated by blending four different edible oils with transparent or similar colors and similar refractive indices to replicate realistic adulteration scenarios. An in-house-built SPRE setup was used to conduct the experiments using a reusable bimetallic Ag-Au SPR sensor chip. The quantification limit for EVOO adulteration was successfully obtained at a low level of 5% (v/v) at room temperature. This optical technique has strength in its convenience, simple instrumentation, ease of sample preparation, minimal solvent usage, non-destructive nature, and rapid real-time analysis. We believe that our experimental outcomes make a valuable contribution to the field, addressing the critical need for reliable methods to ensure the authenticity and quality of EVOO.