Food emulsions : principles, practice and techniques.

Preface The Author Chapter 1 CONTEXT AND BACKGROUND 1.1. Emulsion Science in the Food Industry 1.2. General Characteristics of Food Emulsions 1.2.1. Definitions 1.2.2 Mechanisms of Emulsion Instability 1.2.3. Ingredient Partitioning in Emulsions 1.2.4. Dynamic Nature of Emulsions 1.2.5. Complexity of Food Emulsions 1.3. Emulsion Properties 1.3.1. Dispersed-Phase Volume Fraction 1.3.2. Particle Size Distribution 1.3.3. Interfacial Properties 1.3.4. Droplet Charge 1.3.5. Droplet Crystallinity 1.4. Hierarchy of Emulsion Properties 1.5. Investigation of Emulsion Properties 1.6. Overview and Philosophy Chapter 2 MOLECULAR INTERACTIONS 2.1. Introduction 2.2. Forces of Nature 2.3. Origin and Nature of Molecular Interactions 2.3.1. Covalent Interactions 2.3.2. Electrostatic Interactions 2.3.3. van der Waals Interactions 2.3.4. Steric Overlap Interactions 2.4. Overall Intermolecular Pair Potential 2.5. Bond Strengths and the Role of Thermal Energy 2.6. The Structural Organization of Molecules in Liquids 2.6.1. Thermodynamics of Mixing 2.6.2. Potential Energy Change on Mixing 2.6.3. Entropy Change on Mixing 2.6.4. Free Energy Change on Mixing 2.6.5. The Properties of More Complex Systems 2.7. Molecular Interactions and Conformation 2.8. Higher Order Interactions 2.8.1. Hydrogen Bonds 2.8.2. Hydrophobic Interactions ©1999 CRC Press LLC 2.9. Computer Modeling of Liquid Properties 2.9.1. Monte Carlo Techniques 2.9.2. Molecular Dynamics Techniques Chapter 3 COLLOIDAL INTERACTIONS 3.1. Introduction 3.2. Colloidal Interactions and Droplet Aggregation 3.3. van der Waals Interactions 3.3.1. Origin of van der Waals Interactions 3.3.2. Interdroplet Pair Potential 3.3.3. Hamaker Function 3.3.4. Electrostatic Screening 3.3.5. Retardation 3.3.6. Influence of an Interfacial Layer 3.3.7. General Features of van der Waals Interactions 3.4. Electrostatic Interactions 3.4.1. Origins of Surface Charge 3.4.2. Ion Distribution Near a Charged Surface 3.4.3. Electrostatic Interactions Between Charged Droplets 3.4.4. Ion Bridging 3.4.5. General Features of Electrostatic Interactions 3.5. Polymeric Steric Interactions 3.5.1. Polymeric Emulsifiers 3.5.2. Interdroplet Pair Potential 3.5.3. Distance Dependence of Polymeric Steric Interactions 3.5.4. Optimum Characteristics of Polymeric Emulsifier 3.5.5. General Features of Polymeric Steric Stabilization 3.6. Depletion Interactions 3.6.1. Origin of Depletion Interactions 3.6.2. Interdroplet Pair Potential 3.6.3. General Features of Depletion Interactions 3.7. Hydrophobic Interactions 3.8. Hydration Interactions 3.9. Thermal Fluctuation Interactions 3.9.1. Protrusion Interactions 3.9.2. Undulation Interactions 3.10. Hydrodynamic Interactions and Nonequilibrium Effects 3.11. Total Interaction Potential 3.11.1. van der Waals and Electrostatic 3.11.2. van der Waals, Electrostatic, and Steric 3.11.3. van der Waals and Steric 3.11.4. van der Waals, Electrostatic, and Hydrophobic 3.11.5. van der Waals, Electrostatic, and Depletion 3.12. Predicting Colloidal Interactions in Food Emulsions Chapter 4 EMULSION INGREDIENTS 4.1. Introduction 4.2. Fats and Oils 4.2.1. Molecular Structure and Organization ©1999 CRC Press LLC 4.2.2. Bulk Physicochemical Properties 4.2.3. Fat Crystallization 4.2.4. Chemical Changes 4.3. Water 4.3.1. Molecular Structure and Organization 4.3.2. Bulk Physicochemical Properties 4.4. Aqueous Solutions 4.4.1. Interaction of Water with Ionic Solutes 4.4.2. Interaction of Water with Dipolar Solutes 4.4.3. Interaction of Water with Nonpolar Solutes: The Hydrophobic Effect 4.5. Surfactants 4.5.1. Molecular Characteristics 4.5.2. Functional Properties 4.5.3. Surfactant Classification 4.6. Biopolymers 4.6.1. Molecular Characteristics 4.6.2. Molecular Basis of Conformation and Aggregation 4.6.3. Functional Properties 4.6.4. Modification of Biopolymers 4.6.5. Ingredient Selection Chapter 5 INTERFACIAL PROPERTIES AND THEIR CHARACTERIZATION 5.1. Introduction 5.2. Molecular Basis of Interfacial Properties 5.2.1. Interfaces Between Two Pure Liquids 5.2.2. Interfaces with Adsorbed Emulsifiers 5.3. Thermodynamics of Interfaces 5.3.1. Gas–Liquid Interface in the Absence of an Emulsifier 5.3.2. Gas–Liquid Interface in the Presence of an Emulsifier 5.3.3. Liquid–Liquid Interface 5.3.4. Measurement of the Surface Excess Concentration 5.4. Properties of Curved Interfaces 5.5. Contact Angles and Wetting 5.6. Capillary Rise and Meniscus Formation 5.7. Adsorption Kinetics 5.7.1. Movement of Molecules to an Interface 5.7.2. Incorporation of Emulsifier Molecules at an Interface 5.8. Common Types of Interfacial Membranes 5.9. Interfacial Composition and Competitive Adsorption 5.10. Measurement of Surface and Interfacial Tensions 5.10.1. Du Nouy Ring Method 5.10.2. Wilhelmy Plate Method 5.10.3. Sessile- and Pendant-Drop Methods 5.10.4. Drop-Volume Method 5.10.5. Spinning-Drop Method 5.10.6. Maximum Bubble Pressure Method 5.10.7. Oscillating Jet Method 5.10.8. Capillary Wave Method ©1999 CRC Press LLC 5.11. Interfacial Rheology 5.11.1. Measurement of Interfacial Shear Rheology 5.11.2. Measurement of Interfacial Dilatational Rheology 5.12. Characterization of Interfacial Structure 5.13. Practical Implications of Interfacial Phenomena Chapter 6 EMULSION FORMATION 6.1. Introduction 6.2. Overview of Homogenization 6.3. Physical Principles of Emulsion Formation 6.3.1. Droplet Disruption 6.3.2. Droplet Coalescence 6.3.3. The Role of the Emulsifier 6.4. Homogenization Devices 6.4.1. High-Speed Blenders 6.4.2. Colloid Mills 6.4.3. High-Pressure Valve Homogenizers 6.4.4. Ultrasonic Homogenizers 6.4.5. Microfluidization 6.4.6. Membrane Homogenizers 6.4.7. Homogenization Efficiency 6.4.8. Comparison of Homogenizers 6.5. Factors Which Influence Droplet Size 6.5.1. Emulsifier Type and Concentration 6.5.2. Energy Input 6.5.3. Properties of Component Phases 6.5.4. Temperature 6.6. Demulsification 6.6.1. Nonionic Surfactants 6.6.2. Ionic Surfactants 6.6.3. Biopolymer Emulsifiers 6.6.4. General Methods of Demulsification 6.6.5. Selection of Most Appropriate Demulsification Technique 6.7. Future Developments Chapter 7 EMULSION STABILITY 7.1. Introduction 7.2. Energetics of Emulsion Stability 7.2.1. Thermodynamics 7.2.2. Kinetics 7.3. Gravitational Separation 7.3.1. Physical Basis of Gravitational Separation 7.3.2. Methods of Controlling Gravitational Separation 7.3.3. Experimental Measurement of Gravitational Separation 7.4. Flocculation 7.4.1. Physical Basis of Flocculation 7.4.2. Methods of Controlling Flocculation 7.4.3. Structure and Properties of Flocculated Emulsions 7.4.4. Experimental Measurement of Flocculation ©1999 CRC Press LLC 7.5. Coalescence 7.5.1. Physical Basis of Coalescence 7.5.2. Methods of Controlling Coalescence 7.5.3. Influence of Emulsifier Type and Environmental Conditions 7.5.4. Experimental Measurement of Droplet Coalescence 7.6. Partial Coalescence 7.6.1. Physical Basis of Partial Coalescence 7.6.2. Methods of Controlling Partial Coalescence 7.6.3. Experimental Measurement of Partial Coalescence 7.7. Ostwald Ripening 7.7.1. Physical Basis of Ostwald Ripening 7.7.2. Methods of Controlling Ostwald Ripening 7.7.3. Experimental Measurement of Ostwald Ripening 7.8. Phase Inversion 7.8.1. Physical Basis of Phase Inversion 7.8.2. Methods of Controlling Phase Inversion 7.8.3. Experimental Measurement of Phase Inversion 7.9. Chemical and Biochemical Stability Chapter 8 EMULSION RHEOLOGY 8.1. Introduction 8.2. Rheological Properties of Materials 8.2.1. Solids 8.2.2. Liquids 8.2.3. Plastics 8.2.4. Viscoelastic Materials 8.3. Measurement of Rheological Properties 8.3.1. Simple Compression and Elongation 8.3.2. Shear Measurements 8.3.3. Empirical Techniques 8.4. Rheological Properties of Emulsions 8.4.1. Dilute Suspensions of Rigid Spherical Particles 8.4.2. Dilute Suspensions of Fluid Spherical Particles 8.4.3. Dilute Suspensions of Rigid Nonspherical Particles 8.4.4. Dilute Suspensions of Flocculated Particles 8.4.5. Concentrated Suspensions of Nonflocculated Particles in the Absence of Colloid Interactions 8.4.6. Suspensions of Nonflocculated Particles with Repulsive Interactions 8.4.7. Concentrated Suspensions of Flocculated Particles 8.4.8. Emulsions with Semisolid Continuous Phases 8.5. Major Factors that Determine Emulsion Rheology 8.5.1. Dispersed-Phase Volume Fraction 8.5.2. Rheology of Component Phases 8.5.3. Droplet Size 8.5.4. Colloidal Interactions 8.5.5. Particle Charge Chapter 9 APPEARANCE AND FLAVOR 9.1. Introduction 9.2. Emulsion Flavor ©1999 CRC Press LLC 9.2.1. Flavor Partitioning 9.2.2. Flavor Release 9.2.3. Measurements of Partition Coefficients and Flavor Release 9.3. Emulsion Appearance 9.3.1. Interaction of Light Waves with Emulsions 9.3.2. Overall Appearance 9.3.3. Experimental Techniques Chapter 10 CHARACTERIZATION OF EMULSION PROPERTIES 10.1. Introduction 10.1.1. Research and Development 10.1.2. Quality Control 10.2. Testing Emulsifier Efficiency 10.2.1. Emulsifying Capacity 10.2.2. Emulsion Stability Index 10.2.3. Interfacial Tension 10.2.4. Interfacial Rheology 10.3. Microstructure and Droplet Size Distribution 10.3.1. Microscopy 10.3.2. Static Light Scattering 10.3.3. Dynamic Light Scattering 10.3.4. Electrical Pulse Counting 10.3.5. Sedimentation Techniques 10.3.6. Ultrasonic Spectrometry 10.3.7. Nuclear Magnetic Resonance 10.3.8. Neutron Scattering 10.3.9. Dielectric Spectroscopy 10.3.10. Electroacoustics 10.4. Dispersed-Phase Volume Fraction 10.4.1. Proximate Analysis 10.4.2. Density Measurements 10.4.3. Electrical Conductivity 10.4.4. Alternative Techniques 10.5. Droplet Crystallinity 10.5.1. Dilatometry 10.5.2. Nuclear Magnetic Resonance 10.5.3. Thermal Analysis 10.5.4. Ultrasonics 10.6. Droplet Charge 10.6.1. Electrophoresis 10.6.2. Zetasizer© 10.6.3. Electroacoustics REFERENCES ©1999 CRC Press LLC