FTIR-ATR adulteration study of hempseed oil of different geographic origins

Adulteration of hempseed (H) oil, a well-known health beneficial nutrient, is studied in this work by mixing it with cheap and widely used oils such as rapeseed (R) oil and sesame (Se) and sunflower (Su) oil. Many samples of different geographic origins were taken into account. Binary mixture sets of hempseed oil with these 3 oils (HR, HSe, and HSu) were considered. FTIR spectra of pure oils and their mixtures were recorded, and quantitative analyses were performed using partial least squares regression (PLS) and first-break forward interval PLS methods (FB-FiPLS). The obtained results show that each particular oil can be very successfully quantified (R²(val) > 0.995, RMSECV 0.9%–2.9%, RMSEP 1.0%–3.2%). This means that FTIR coupled with multivariate methods can rapidly and effectively determine the level of adulteration in the adulterated hempseed oil for these studied and frequently used adulterant oils. Also, the relevant variables selected by FB-FiPLS could be used for verification of hempseed oil adulteration.