Feasibility of geographic authentication of Sicilian pistachios by Fourier-Transform Infrared spectroscopy

Quality and traceability are essential to food industry, spurring adoption of non-invasive methods for rapid assessment of key product attributes. This study investigates the feasibility of portable Fourier-Transform Infrared spectroscopy with attenuated total reflectance (FTIR-ATR) for fast, in-situ and non-destructive authentication of the geographical origin of Sicilian pistachios (Pistacia vera L.). A pilot set of pistachio kernels harvested in 2023 was analysed, including samples from the “Pistacchio Verde di Bronte” and “Pistacchio di Raffadali” production districts – both recognized with the Protected Designation of Origin (PDO) label – and samples from an uncertified Sicilian growing area. These samples were subsequently compared with additional Sicilian and foreign pistachio kernels, mostly harvested in 2025, to validate the proposed authentication model. The method successfully disentangled Sicilian pistachios from foreign samples and distinguished Sicilian pistachios of the same origin harvested in different years, demonstrating robustness in detecting variations due to geographic origin and harvesting year. Complementary physico-chemical analysis, including moisture content, cotyledon colour, and total polyphenol content, revealed differences between Sicilian and foreign samples consistent with the spectral discrimination, thus corroborating the identification of the chemical features responsible for sample discrimination. These findings support the potential of FTIR-ATR spectroscopy for assessing the quality and geographical origin of pistachio nuts.