A team from the University of Cordoba demonstrated that a portable near-infrared spectral sensor can accurately assess olive oil quality, offering a practical, low-cost alternative to laboratory methods.
Bringing Olive Oil Quality Control Out of the Lab
A recent study led by researchers from the University of Cordoba highlights a new development in olive oil quality assessment: a portable near-infrared spectroscopy (NIRS) sensor capable of delivering laboratory-comparable results in real-world conditions. Published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, the work focuses on optimizing methodological factors to enhance the accuracy and usability of a compact NIR device based on linear variable filter (LVF) technology (1).
The research, conducted by María-del-Mar Garrido-Cuevas, Ana-María Garrido-Varo, María-Teresa Sánchez, and Dolores Pérez-Marín from the Faculty of Agriculture and Forestry Engineering (ETSIAM), addresses a pressing industry challenge. Traditional quality control methods for olive oil, essential for maintaining authenticity and preventing fraud, are expensive, require specialized personnel, and can take considerable time (1).
Portable NIR Sensor Brings Lab-Quality Olive Oil Testing to the Field © Marko-chronicles-stock.adobe.com
Why Olive Oil Quality Matters
Spain leads the world in olive oil exports, and ensuring product authenticity is critical both for consumers and regulatory authorities. Conventional quality indices such as acidity, peroxide value, and fatty acid ethyl esters are usually assessed using benchtop instruments in dedicated laboratories. But the logistics and costs involved limit routine testing, especially for smaller producers (1).
“There’s a clear need for rapid, cost-effective, multiparameter analytical methods,” the authors write (1). The study proposes portable NIRS as a solution that could democratize access to reliable olive oil quality assessment tools, especially in fragmented production landscapes (1–3).
A Close Look at the Spectroscopy
The team evaluated a handheld LVF-based NIRS device against a laboratory-grade benchtop spectrometer using 810 olive oil samples. Both instruments applied modified partial least squares (MPLS) regression for calibration development. Researchers paid particular attention to optimizing sample presentation, ultimately finding that transmission mode using 10 mm optical pathlength polystyrene cuvettes yielded the best results for the portable device (1).
Despite having a narrower spectral range (908–1676 nm) and lower resolution compared to the laboratory device (400–2500 nm), the portable sensor achieved remarkably strong predictive capabilities for key quality parameters (1). For example:
According to established guidelines, these values represent excellent or good predictive accuracy, reinforcing the portable device’s potential (1,2).
The researchers stress the importance of metrics such as the residual predictive deviation (RPDcv) and the coefficient of variation (CV) alongside the coefficient of determination (r²cv). While the benchtop instrument performed slightly better in most categories, the portable sensor’s results were notably comparable, particularly for acidity and fatty acid ethyl esters (1).
Advancing Methodology and Accessibility
One of the study’s key contributions lies in its systematic evaluation of methodological factors—sample presentation, temperature control, calibration protocols—that affect NIRS performance in olive oils (1). The sharp peaks characteristic of oil spectra make them highly sensitive to operational conditions, and the authors emphasize that previous guidelines, such as those from Garrido et al. in reference (2), require updating to align with advances in instrumentation and chemometric software.
“This research provides both a novel scientific framework and practical tools for quality control in the olive oil sector,” the authors note. Their findings have direct implications for producers, especially small and medium enterprises that typically lack access to high-cost analytical equipment (1).
Broader Implications for the Industry
The work underscores how portable NIRS technology could significantly improve transparency, traceability, and fraud prevention in the olive oil market. As non-International Olive Council (IOC) countries like the United States, Brazil, and Japan continue to play important roles in global olive oil trade, ensuring product authenticity becomes even more essential (1).
By offering a validated, portable solution, the research by María-del-Mar Garrido-Cuevas and her colleagues points the way toward more equitable access to quality control tools—a shift that could benefit both producers and consumers worldwide (1).
References
(1) Garrido-Varo, A. M.; Sánchez, M. T.; Pérez-Marín, D. Assessment of a Portable Near-Infrared Spectral Sensor for Enhancing Virgin Olive Oil Quality Control. Spectrochim. Acta, Part A 2025, 126288. DOI: 10.1016/j.saa.2025.126288
(2) Garrido-Varo, A.; García-Olmo, J.; Pérez-Marin, M. D. Applications in Fats and Oils. In Near-Infrared Spectroscopy in Agriculture; Agron. Monogr. 44; 2004; pp 487–558. DOI: 10.2134/agronmonogr44.c19
(3) Rossi, F. A. B.; dos Santos Tonial, L. M. Portable vs Benchtop NIR Spectrometers for Rapid Chemical Analysis: A Study with Different Samples. In Ciências Agrárias: Inovações, Sustentabilidade e Desafios para o Século XXI; Editora Científica Digital: 2025; Vol. 1, pp 101–119. https://downloads.editoracientifica.com.br/articles/250218861.pdf (accessed 2025-07-15).
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