Phenolic Profile Characterization of Extra Virgin Olive Oils from the Omani Market Using a Salt-Assisted Extraction and LC-MS/MS Approach

This study investigates the phenolic composition of extra virgin olive oil (EVOO) from the Omani market and optimizes the phenolic extraction process. The addition of 10% (w/v) sodium chloride to the extraction solvent increased phenolic recovery by 20–30%. Feature importance analysis identified solvent polarity, influenced by solvent type, salt concentration, and volume, as the key factor driving extraction efficiency. A validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) method quantified ten phenolic compounds in six commercial EVOO samples. Acid values ranged from 0.01% to 0.11%, and peroxide values were below 12 meq O₂ kg⁻¹, confirming compliance with EVOO quality standards. Total phenolic content ranged from 116 to 250 mg kg⁻¹. Two locally produced Omani oils exhibited phenolic profiles comparable to high-quality Mediterranean EVOOs. Elevated hydroxytyrosol levels indicate phenolic transformation during storage. This study provides baseline data supporting quality control and nutritional evaluation of EVOOs in the Omani market.