Rapid evaluation of edible hemp oil quality using NMR and FT-IR spectroscopy

Abstract Since Cannabis species include psychoactive varieties containing high levels of Δ9-tetrahydrocannabinol (THC), psychotropic properties could be wrongly attributed to hemp-seed oil obtained from Cannabis sativa . Hemp oil does not exert any psychotic effect; on the contrary, it may provide significant health benefits, because it has an optimum proportion of ω-6 to ω-3 fatty acids (3:1). Six samples of cold pressed hemp-seed oils were studied by nuclear magnetic resonance (NMR) and Fourier-transformed infrared spectroscopy (FT-IR). These methods were applied to evaluate the ratio of ω-6 to ω-3 fatty acids and to control the quality of hemp oils. FT-IR method allowed us to distinguish three oils with the highest level of γ-linolenic acid. Additionally, NMR spectroscopy was applied to determine the ω-6 to ω-3 ratio. The outcomes of the NMR experiment are in agreement with GC outcomes measures. The results indicate that NMR and FT-IR may be used in routine evaluation of hemp-seed oil quality as a fast and reliable method of verification of ω-6 to ω-3 ratio and origin of the oil.