Raman on the palm: handheld Raman spectroscopy for enhanced traceability of palm oil.

Determining the geographic origin of palm oil in West Africa is vital for economic, environmental, and health reasons. It enhances traceability, protects local farmers, supports conservation by monitoring deforestation, and reduces food fraud, ensuring quality and regulatory compliance. Portable Raman spectroscopy offers a rapid method to identify the origin of palm oils from West Africa. Using principal component analysis (PCA), distinct clusters in scores plots were observed which reflected the geographic origin of the palm oils, with loadings from the first principal component (PC-1) highlighting β-carotene as a major source of variation among the samples. To quantify β-carotene content, a partial least squares regression (PLS-R) model was developed in coconut oil as the base oil as it is known to be β-carotene free. Once calibrated, PLS-R was used to rank the palm oil from West Africa based on their β-carotene levels. The resulting models in coconut oil demonstrated strong linearity and predictive performance, with R² and Q² values of 0.9848 and 0.9552, respectively, alongside low root mean square errors of cross-validation (0.1282 mM) and prediction (0.0747 mM); moreover, this model allows the palm oils to be ranked based on β-carotene content which was entirely reflective of the oils position in PC-1 from PCA. These findings underscore the potential of Raman spectroscopy as an effective tool for authenticating the geographic origin of palm oil from West Africa.