Authentication of flours using chromatographic and spectroscopic techniques: A comprehensive review

Abstract

Background: Flour is a powdered substance obtained by grinding cereal grains or other starch-rich foods, formed through a milling process that reduces the grain to a fine powder. Flour is a staple ingredient highly susceptible to adulteration, mislabelling, and cross-contamination, posing risks to food safety, quality, and consumer trust. The increasing complexity of flour matrices and supply chains has intensified the need for reliable analytical tools for authentication. Scope and approach: This review systematically evaluates recent advances in chromatographic and spectroscopic techniques for flour authentication, covering studies from 2015 to 2025 (chromatography) and 2020–2025 (spectroscopy). Both targeted and non-targeted approaches are discussed, including GC, LC, and CE, as well as NIR, FTIR, hyperspectral imaging, fluorescence, Raman, and LIBS. Particular attention is given to chemometric and machine learning strategies for classification and quantification, alongside key methodological considerations such as sample preparation, data processing, and validation. Key findings and conclusions: Chromatographic methods provide high sensitivity and molecular specificity, enabling targeted detection of markers, while spectroscopic techniques offer rapid, non-destructive, and high-throughput screening based on chemical fingerprints. Despite significant progress, major challenges remain, including matrix complexity, environmental variability, limited standardization, and poor model transferability across instruments and datasets. Detection of low-level adulteration in complex or blended flours remains particularly challenging. Future research is expected to focus on multi-sensor data fusion, expansion of open spectral databases, robust validation frameworks, and integration of portable devices with digital infrastructures. These developments will be essential to improve robustness, scalability, and real-world implementation of flour authentication strategies.