Investigating the potential of aqueous enzymatic extraction of safflower (Carthamus tinctorius L.) seed oil: Process optimization and oil characterization

Abstract

Safflower seed oil was extracted by aqueous enzymatic extraction (AEE) with a combination of three enzymes: hemicellulase, pectinase, and protease. A Response Surface Methodology (RSM) was performed to optimize the operating conditions: Temperature, pH, and incubation time. Analysis of variance allowed studying the variables' linear, quadratic, and interaction effects. The optimized extraction conditions resulted in 85% oil recovery referring to the conventional Soxhlet extraction (SE). Subsequently, a comparative analysis was conducted to evaluate the quality and composition of oils obtained by SE and AEE. The results revealed that the two oils had similar values of peroxide index, conjugated dienes and trienes, and fatty acid composition. AEE-oil had a lighter yellow color (L* = 31.8 Vs. 24.7) and was richer in polyphenols (147 Vs. 101 mg GAE/Kg of oil), but it was more acidic (2.75% Vs. 1.56% linoleic acid) and less stable (2.86h Vs. 5.66h induction time) with less tocopherol (302 Vs. 409 mg/kg oil) and carotenoid content (0.42 Vs. 0.57 mg/kg oil) than SE-oil. Our findings demonstrated that RSM-based optimization is an efficient and time-saving approach, which significantly improved oil extraction. Finally, we suggested several solutions to further improve the quality and quantity of the obtained AEE-safflower seed oil, paving the path for other future research possibilities.