NIR, IR, UV-vis, and NMR Spectroscopy Drive New Insights in Olive Oil Quality and Fraud Prevention

NIR, IR, UV-vis, and NMR Spectroscopy for testing Olive Oil for fraud prevention © megaflop - stock.adobe.com

Extra virgin olive oil (EVOO) is a cultural and culinary staple, especially within Mediterranean countries. However, its high value also makes it a prime target for food fraud, necessitating new, accurate methods for quality assurance. Traditional chemical testing for olive and EVOO quality is reliable but often slow and labor-intensive. To address this, researchers Alessio Cappelli, Sirio Cividino, Veronica Redaelli, Gianluca Tripodi, Gilda Aiello, Salvatore Velotto, and Mauro Zaninelli from the Department of Human Science and Quality of Life Promotion at Università Telematica San Raffaele in Rome published a comprehensive review in Agriculture. They explored spectroscopic techniques, imaging, and other non-destructive approaches to enhance the speed and efficiency of EVOO analysis (1).

A Push for Fast, Non-Destructive Analysis

The research team emphasized the drawbacks of traditional EVOO testing methods, which are typically invasive and require extensive sample preparation. Instead, they highlighted how newer technologies, like near-infrared (NIR) spectroscopy and red-green-blue (RGB) color imaging, offer rapid and non-destructive analysis, making them particularly valuable for quality monitoring directly in the field or mill (1–3).

RGB imaging and NIR spectroscopy, for instance, have shown significant potential for assessing olive ripeness and quality. While NIR spectroscopy allows for portable, quick readings of crucial parameters, RGB imaging visually monitors color, a proxy for maturity. However, the authors noted that combining these imaging techniques with measurements of olive flesh hardness is essential, as color alone may not accurately reflect ripeness. Factors like drought stress or excessive sun exposure can cause premature skin darkening while the flesh remains unripe, which could compromise the oil's quality (1).

Read More: Product Adulteration Analysis

New Tools to Address Fraud and Authenticate EVOO

Spectroscopy is gaining traction for its unique ability to detect fraud and verify geographical or varietal origins of EVOO. NIR and mid-infrared (IR) spectroscopies, along with visible imaging and UV-Visible analyses, have all demonstrated potential in assessing various quality markers. These include determining specific sterols, fatty acids, and polyphenol content—key elements tied to authenticity and health benefits (1).

Notably, NIR spectroscopy shows particular promise for fraud detection. With portable, cost-effective devices becoming more readily available, even small-scale producers can benefit from this advanced technology. The review highlights how online NIR monitoring could soon offer real-time data on EVOO quality, potentially reshaping the quality control process across the olive oil supply chain (1–3).

Exploring the Potential of NMR for Olive and EVOO Quality

While NIR and IR have demonstrated utility, the review also discussed the emerging use of nuclear magnetic resonance (NMR) spectroscopy in both olive and EVOO quality evaluation. NMR offers a unique perspective by analyzing the internal structure of the olive drupe, providing valuable information on oil and water distribution, and cellular changes during ripening (1).

The team found that 1H, 13C, and 31P NMR spectroscopies could non-invasively monitor changes in specific compounds within olives and EVOO. This detailed insight may eventually support more precise harvesting time decisions, optimizing both yield and quality. Furthermore, NMR’s sensitivity to EVOO’s oxidative stability could become a crucial metric in maintaining freshness and health benefits during storage and distribution (1).

Innovative Solutions for a Sustainable Olive Oil Industry

The review underscores the essential role of innovative, non-destructive techniques in the future of EVOO production. NIR spectroscopy’s potential for real-time, online monitoring could significantly reduce production costs and improve product consistency. However, the researchers caution that further work is needed to refine calibration methods, ensuring accuracy across various olive varieties and growing conditions (1).

In their conclusion, the authors emphasized the need for continued research, particularly in integrating techniques like RGB imaging with NIR and mechanical assessments to ensure robust and accurate maturity indicators. They foresee a future where advanced spectroscopy not only improves quality control but also democratizes technology access for small producers, supporting sustainability and authenticity across the industry (1).

This review offers a comprehensive look at how non-destructive techniques can transform EVOO production, from field to bottle. Through ongoing research and technological development, these innovative solutions hold promise for enhancing quality, reducing fraud, and upholding the integrity of one of the world’s most cherished foods (1).

References

(1) Cappelli, A.; Cividino, S.; Redaelli, V.; Tripodi, G.; Aiello, G.; Velotto, S.; Zaninelli, M. Applying spectroscopies, imaging analyses, and other non-destructive techniques to olives and extra virgin olive oil: A systematic review of current knowledge and future applications. Agriculture 2024, 14 (7), 1160. DOI: 10.3390/agriculture14071160

(2) Yılmaz-Düzyaman, H.; de la Rosa, R.; Velasco, L.; Núñez-Sánchez, N.; León, L. Oil Quality Prediction in Olive Oil by Near-Infrared Spectroscopy: Applications in Olive Breeding. Agriculture 2024, 14 (5), 721. DOI: 10.3390/agriculture14050721

(3) Arroyo-Cerezo, A.; Yang, X.; Jiménez-Carvelo, A. M.; Pellegrino, M.; Savino, A. F.; Berzaghi, P. Assessment of Extra Virgin Olive Oil Quality by Miniaturized Near Infrared Instruments in a Rapid and Non-Destructive Procedure. Food Chemistry, 430, 137043. DOI: 10.1016/j.foodchem.2023.137043