ω-3 and ω-6 fatty acid production under subcritical water processing test subjects: hemp seed and crude palm oils

Abstract

Subcritical water processing of organic material has become one of the most interesting technologies to perform hydrolysis or extraction processes of organic compounds that aren't soluble in water at standard conditions. The main advantages of the use of water in the subcritical region come from having a cleaner and sustainable process, after exiting the high temperature and pressure region, lower solvent costs, and safer operating conditions. In this work, subcritical water hydrolysis of hemp seed and crude palm oils was performed under batch (For both material types) and continuously (For hemp seed oil only) to evaluate the hydrolysis yield, fatty acid stability, and thermal decomposition. To determine the technical feasibility of applying this process to consistently produce ꞷ-3 and ꞷ-6 fatty acids from the vegetable oils. Obtained results showed that subcritical hydrolysis effectively decomposes the triglyceride molecules into fatty acids, obtaining mass concentrations above 80% at temperatures below 573K in both materials. Moreover, analytical chemistry analysis performed on the hemp seed oil hydrolyzates showed that a significant fraction of the released fatty acids become dimers that are less likely to be digested by the human body. Also, a less significant amount of thermal oxidation was observed mainly on batch experimentation, where long chain aldehydes were identified. In addition, the observed polymerization level can be desired on industrial products manufacturing such as resins, adhesives, surfactants, and insulation fabrication, opening a new value-added alternative to low esteemed materials such as palm oil.