Contents Supercritical Fluid Extraction of Sclerocarya birrea Kernel Oil N Taseski 24688819 Dissertation submitted in fulfilment of the requirements for the degree Magister Scientiae in Chemical Engineering at the Potchefstroom Campus of the North-West University Supervisor: Prof J Markgraaff Co-supervisor Prof HCM Vosloo Assistant-supervisor Prof LJ Grobler May 2015 0 Contents CONTENTS Abstract ................................................................................................................................................................................................ iii Acknowledgement ............................................................................................................................................................................. v Acronyms ............................................................................................................................................................................................. vi List of Figures ................................................................................................................................................................................. viii List of Tables ...................................................................................................................................................................................... ix Chapter 1: Introduction ..................................................................................................................................................................... 1 1.1 Background and Motivation ............................................................................................................................................... 1 1.2 Problem Statement ................................................................................................................................................................. 1 1.3 Aims and Objectives ............................................................................................................................................................. 2 Chapter 2: Background and Literature Review ........................................................................................................................ 3 2.1 Marula ........................................................................................................................................................................................ 3 2.1.2 The Applications of Marula ........................................................................................................................................ 4 2.2 Separation Techniques ....................................................................................................................................................... 11 2.2.1 Pressing .......................................................................................................................................................................... 11 2.2.2 Solvent Extraction ...................................................................................................................................................... 12 2.2.3 Combined Expeller and Solvent Extraction Method ....................................................................................... 13 2.2.4 Novel Methods: Possible Solutions to Drawbacks of Traditional Techniques ....................................... 13 2.3 Supercritical Fluid Extraction (SFE) ............................................................................................................................. 14 2.3.1 The SFE Process ......................................................................................................................................................... 14 2.3.2 Principles of Operation ............................................................................................................................................. 16 2.3.3 Mathematical Modelling and Experimental Results Evaluation .................................................................. 16 2.3.4 SFE-CO2 Processing .................................................................................................................................................. 21 2.3.5 Conclusions from Literature .................................................................................................................................... 29 2.4 Fats and Oils ......................................................................................................................................................................... 30 2.4.1 Origin and Classification .......................................................................................................................................... 30 2.4.2 Oil Characterization ................................................................................................................................................... 32 Chapter 3: Experimental Procedure and Results ................................................................................................................... 35 Scope .............................................................................................................................................................................................. 35 3.1 Material Preparation ........................................................................................................................................................... 35 3.2 Supercritical Fluid Extraction ......................................................................................................................................... 36 3.2.1 System Information .................................................................................................................................................... 36 3.2.2 Extraction Conditions ................................................................................................................................................ 38 3.3 Characterisation of Extracts ............................................................................................................................................. 41 3.3.1 Fatty Acid Analysis .................................................................................................................................................... 41 i Contents 3.3.2 Free Fatty Acid, Peroxide, and Iodine Values ................................................................................................... 43 3.3.3 Vitamin Analyses ........................................................................................................................................................ 44 3.4 Extract Residue Analysis .................................................................................................................................................. 44 3.5 Marula Kernel Cell Structure .......................................................................................................................................... 44 Chapter 4: Discussion .................................................................................................................................................................... 47 4.1 Extraction Parameter Optimisation ................................................................................................................................ 47 4.1.1 Influence of Extraction Temperature .................................................................................................................... 47 4.1.2 Influence of Extraction Pressure ............................................................................................................................ 49 4.1.3 Yield vs. Solvent ......................................................................................................................................................... 52 4.5 Solubility Prediction vs. Empirical Data ..................................................................................................................... 53 4.2 Oil Quality and Composition ........................................................................................................................................... 54 4.2.1 Oil Characterisation ................................................................................................................................................... 54 4.2.2 Comparing Cold Pressed Oils vs. SFE-Extracted Oils ................................................................................... 56 4.3 Extract Residue .................................................................................................................................................................... 57 4.4 Conclusion ............................................................................................................................................................................. 58 Chapter 5: Conclusions and Recommendations .................................................................................................................... 60 5.1 Conclusions ........................................................................................................................................................................... 60 5.2 Further Research: Recommendations ........................................................................................................................... 61 5.2.1 Effects