Lipase-catalyzed interesterification between canola oil and fully-hydrogenated canola oil in contact with supercritical carbon dioxide

• Author / Creator

  Jenab, Ehsan

• Despite the policies targeting reduction of partially hydrogenated fats because of concerns over trans fatty acids (TFA), which have been shown to be a major risk factor for cardiovascular diseases, partial hydrogenation is still employed in the margarine industry. Lipase-catalyzed interesterification is an alternative method to eliminate TFA formation in hardened fats. However, conventional techniques suffer from long reaction times or use of organic solvents. The objective of this thesis was to develop lipase-catalyzed interesterification between canola oil and fully-hydrogenated canola oil (FHCO) using supercritical carbon dioxide (SCCO2).
  Fundamental physical properties such as viscosity, density and volumetric expansion of canola oil and its blend with FHCO were determined at different temperatures and pressures. When equilibrated with SCCO2 at pressures of up to 10 MPa, the viscosity of canola oil and its blend decreased by 80-90% of that at atmospheric pressure. As well, the density at elevated pressures increased by 3.5-5%, while volumetric expansion increased by 40-46%.
  The performance and reusability of Lipozyme TL IM and RM IM for interesterification between canola oil and FHCO under SCCO2 were investigated. Both enzymes showed similar performance. Exposure time of up to 12 h and pressurization/depressurization steps of up to 12 times under SCCO2 did not affect the activity or the structure of the enzymes significantly. Both enzymes showed good reusability for several times for interesterification without any significant change in degree of interesterification. Pressurization/depressurization reduced the moisture content of the enzymes and consequently the formation of reaction intermediates during the reaction.
  Optimal reaction conditions to obtain the maximum conversion rate were 65 °C/10 MPa/2 h/6% (w/v) Lipozyme TL IM of substrates. The triglyceride (TG) composition, thermal behaviour, solid fat content, polymorphism and microstructural and rheological properties of initial blends were modified considerably due to the formation of new mixed TG during interesterification.
  The fundamental data and optimized reaction conditions obtained in this research are essential for process and equipment design. As well, the physicochemical characterization of final products will aid in the formulation of more healthy products and address a critical industrial demand in terms of formulation options for margarines and similar products.

• Subjects / Keywords

  • Supercritical carbon dioxide
  • Fully-hydrogenated canola oil
  • Enzymatic interesterification
  • Canola oil
  • Carbon dioxide-expanded lipid

• Graduation date

  Spring 2013

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R37D4P

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.