# Autofluorescence Profiling of Virgin Olive Oil: Impact of Rosemary and Basil Flavoring During Storage

## TL;DR

This study uses autofluorescence to track how rosemary and basil flavoring affects the shelf life and oxidation of virgin olive oil during storage.

## Contribution

The study introduces a novel spectrofluorometric method to monitor olive oil freshness and stability using autofluorescence profiles.

## Key findings

- Autofluorescence measurements revealed dynamic spectral changes in olive oil over nine months of storage.
- Rosemary and basil flavoring slowed oxidation by transferring antioxidants into the oil.
- A Zone III/Zone II fluorescence ratio below 0.6 indicates oil stored for more than three months.

## Abstract

The consumption of virgin olive oil has been associated with a broad spectrum of beneficial effects. These health outcomes are attributed not only to its high monounsaturated fatty acid content but also to its bioactive components. Nowadays, the flavoring of olive oil has gained popularity to improve its antioxidant properties, modify its sensory characteristics, and enhance its oxidative stability. This study explores spectrofluorometry as a fast, non-destructive, and eco-friendly tool to monitor oxidation and predict shelf life in virgin olive oils (VOOs). Both unflavored and flavored rosemary and basil samples were studied. Over nine months of storage, monthly autofluorescence measurements at 330 nm excitation revealed dynamic spectral changes. These changes were mapped into three distinct emission zones (I, II, and III), providing a spectral fingerprint of oil freshness and stability. Autofluorescence analysis revealed that oxidation-related emission increased while pigment-related emission decreased over time, especially within the first five months. Rosemary and basil flavoring slowed degradation due to antioxidant migration from the herbs. It is proposed that a ratio between the fluorescence intensity of Zone III/Zone II of the spectrum of less than 0.6 indicates oils stored for more than three months.