Evaluation of Novel Rapid Analytical Methods to Categorize Extra Virgin Olive Oil Based on the Coulometrically Determined Antioxidant Capacity and on the Spectrophotometric Assessment of Phenolic Compounds

Molecules. 2023 Mar 30;28(7):3108. doi: 10.3390/molecules28073108.

Abstract

The lack of a practical "fit for the purpose" analytical protocol is the main limitation that has hampered the exploitation of the EFSA analytical health claim on the extra virgin olive oil (EVOO) biophenols, more than ten years since its introduction. In this work, two analytical methods recently developed in our laboratories for categorizing EVOO have been evaluated on a set of 16 samples from Cilento (Campania Region, southern Italy) and compared to other commonly used quality indexes. The Coulometrically Determined Antioxidant Capacity (CDAC) is associated with the component responsible for the health-promoting properties and oxidative stability of EVOO. The Fast Blue BB (FBBB) assay consists of the spectrophotometric (420 nm) determination of biophenols-FBBB diazonium coupling products generated in unfractionated EVOO. The FBBB assay and HPLC-UV reference method provide values highly correlated to each other. Fourteen of sixteen EVOO samples with CDAC > 10 mmol kg-1 and FBBB absorbance > 0.5 had HPLC-determined biophenols > 250 mg kg-1, and therefore eligible for the EFSA health claim. Consistently, two EVOO samples with HPLC-determined biophenols < 250 mg kg-1 had CDAC values and FBBB absorbance below the respective thresholds. CDAC and FBBB assays are proposed individually or in combination as methods to categorize EVOO samples in alternative to HPLC-UV.

Keywords: EFSA health claim; antioxidants; coulometrically determined antioxidant capacity; extra virgin olive oil; fast blue BB assay; phenolic compounds.

MeSH terms

  • Antioxidants* / analysis
  • Antioxidants* / metabolism
  • Fatty Acids / analysis
  • Fatty Acids / chemistry
  • Olive Oil* / chemistry
  • Olive Oil* / metabolism
  • Phenols* / analysis
  • Phenols* / chemistry
  • Principal Component Analysis
  • Spectrophotometry*
  • Time Factors

Substances

  • Olive Oil
  • Phenols
  • Fatty Acids
  • Antioxidants
  • Fast Blue BB

Grants and funding

The research was partly supported by the “COMPETiTiVE-Claims of Olive oil to iMProvE the market ValuE” project (AGER 2 Project)—grant number 2016-0174. The NutrAge FOE project of Italian National Research Council (CNR) and “MODELLI—Modelli di gestione di sistemi agricoli per la conservazione e tutela delle risorse idriche” Campania Region—PSR 2014/2020, intervention 14.1, action 2, are also acknowledged.