Enhancing bioactive compound extractability and antioxidant properties in hemp seed oil using a ternary mixture approach of polar and non-polar solvents

The present study is devoted to optimizing process parameters for solvent extraction to improve both the yield and quality of hemp seed oil. To this end, an augmented simplex lattice mixture design was carried out involving three solvents with different polarities: n-hexane, 2-propanol, and ethyl acetate. The findings indicated that the optimal blend for obtaining oil with a high yield and excellent quality was 40 % n-hexane, 40 % 2-propanol, and 20 % ethyl acetate. This ternary mixture gave a maximum yield of 33.24 % and extracted an oil very rich in bioactive compounds, enabling us to replace 60 % of the hexane with two other extraction solvents, 2-propanol and ethyl acetate, which are less toxic to human health and more environmentally friendly. The ideal blend was able to extract an oil with high levels of total phenolic content (226.43 mg GAE/kg), total tocopherols (458.61 mg/kg), total phytosterols (6299.44 mg/kg), and total carotenoids and chlorophylls (19.92 and 66.59 mg/kg, respectively). Moreover, the evaluated oil exhibited significant antioxidant activity as determined by DPPH and FRAP tests (74.64 % reduction and 49.16 mg TEg/100 g, respectively). This oil's richness in bioactive compounds gave it better oxidation stability. Furthermore, the phenolic profile of hemp seed oil from every solvent mixture was unveiled using HPLC-DAD/ESI-MS2, identifying many phenolic compounds, such as Ncaffeoyltyramine, cannabisins (A, B, C and O) isocannabisine N, demethylgrossamide, 3,3-didemethylgrossamide, 3,3-demethylheliotropamide, and grossamide. Moreover, the analyses indicated a substantial presence of hydroxycinnamic acids and lignan amides (up to 58.79 and 85.01 mg/kg, respectively) in the oil extracted with a binary mixture of 2-propanol - ethyl acetate (50-50 %).