Pressurized ethanol for simultaneous oil extraction of canola seed and rice bran: Comparative evaluation and characterization

This work aimed to investigate the simultaneous pressurized liquid extraction (PLE) of oil from canola seeds (CS) and rice bran (RB). Ethanol was used as a solvent and the influence of temperature (40, 60 and 80 °C) and CS:RB ratio (60:40, 70:30 and 80:20, w/w) on oil removal and composition was determined. Soxhlet extraction was conducted for comparative purposes. The highest recoveries obtained by PLE were achieved at 80 ºC and CS:RB of 60:40 and 80:20, considering oil yield and active compound content. At this temperature, oil recovery from CS was 3.8 times higher than that obtained from RB. The fatty acid profile showed a balanced distribution between saturated and unsaturated fatty acids, with greater solubilization of the unsaturated fraction at 40 °C. The content of lipophilic compounds was influenced by temperature, since heating favored the extraction of γ-tocopherol and phytosterols (β-sitosterol and stigmasterol). γ-oryzanol, strongly associated with RB, showed a higher content in the oil obtained at 40 °C and CS:RB 60:40. Higher concentrations of phenolic acids were detected in oils obtained from extractions using higher concentrations of RB. Nicotinic acid was efficiently removed by PLE at 60 °C and 80 °C. The oils obtained at 80 °C and CS:RB 60:40 showed greater antioxidant potential, especially associated with ferulic acid. The oxidative stability of the oils was shown to be highly correlated with the levels of tocopherols and γ-oryzanol, compounds that act in protecting the oil against oxidation.