Food Structuring
Reader ........................................................................................................................................................... 4
1 Food Structures, Building Blocks and Food Properties ......................................................................... 4
1.1 Introduction to food structure .................................................................................................. 4
1.2 Building blocks ........................................................................................................................... 5
1.3 Phase and state diagrams.......................................................................................................... 8
1.4 Glass transition .......................................................................................................................... 9
1.5 Rules for estimation of food properties and effect of structure on some food properties .... 10
1.6 Summary.................................................................................................................................. 10
2 The State Diagram and the Glass Transition ....................................................................................... 11
2.1 The states of foods .................................................................................................................. 11
2.2 Gases, vapors and liquids and vapor ....................................................................................... 11
2.3 Diagrams .................................................................................................................................. 13
2.4 The glass transition .................................................................................................................. 17
2.5 Semi-crystallinity, chemical and physical crosslinking ............................................................ 21
2.6 Some examples........................................................................................................................ 23
2.7 Summary.................................................................................................................................. 33
3 Crystallization and Matrix Formation .................................................................................................. 35
3.1 Introduction ............................................................................................................................. 35
3.2 Crystals .................................................................................................................................... 35
3.3 Food structure from crystals ................................................................................................... 36
3.4 Crystallization and the state diagram ...................................................................................... 37
3.5 Crystallization dynamics .......................................................................................................... 39
3.6 Structure stability and evolution ............................................................................................. 42
3.7 Freezing and thawing .............................................................................................................. 43
4 Barrier Technology in Food Products .................................................................................................. 54
4.1 Introduction ............................................................................................................................. 54
4.2 Kinetics: Diffusion .................................................................................................................... 59
4.3 Prevention of defects in barrier films...................................................................................... 65
4.4 Preparation procedures........................................................................................................... 67
4.5 Mechanical behavior ............................................................................................................... 70
1
, 4.6 Wetting behavior ..................................................................................................................... 70
5 Emulsions: Principles and Preparation ................................................................................................ 73
5.1 Introduction ............................................................................................................................. 73
5.2 Emulsions-based products, types of emulsions and their applications .................................. 73
5.3 Interfacial tension, interfacial energy and Laplace pressure .................................................. 74
5.4 Physical stability of emulsion .................................................................................................. 75
5.5 Physical characterization of emulsions ................................................................................... 79
5.6 Making emulsions using flow fields......................................................................................... 82
6 Structuring of biopolymer products .................................................................................................... 91
6.1 Introduction to structuring biopolymer products ................................................................... 91
6.2 The role of polymer chain structure and length in polymer properties ................................. 91
6.3 Water binding in biopolymer mixtures ................................................................................... 92
6.4 Phase behavior of polymer-solvent mixtures – Thermodynamic composition ...................... 95
6.5 Phase behavior of biopolymer mixtures – Equilibrium composition ...................................... 97
6.6 Rheological properties of (semi-solid) food products – Kinetic composition ......................... 98
6.7 Processing of dense biopolymer systems.............................................................................. 102
Lectures ..................................................................................................................................................... 108
2 Lecture 07/09 .................................................................................................................................... 108
2.1 Recap lecture 1 ...................................................................................................................... 108
2.2 States in foods ....................................................................................................................... 109
2.3 The glass transition ................................................................................................................ 110
2.4 The use of state diagrams to analyze processes ................................................................... 112
2.5 Example: two types of candy................................................................................................. 114
2.6 Example: baking bread .......................................................................................................... 116
2.7 Summary................................................................................................................................ 116
3 Lecture 11/09 .................................................................................................................................... 118
3.1 Crystallization: Thermodynamics and state diagrams........................................................... 118
3.2 Crystallization: Cryostabilisers and cryoprotectants ............................................................. 123
3.3 Crystallization application: freeze drying .............................................................................. 125
3.4 Crystallization dynamics: Nucleation and crystal growth ..................................................... 126
3.5 Crystallization dynamics application: Freeze alignment and structuring.............................. 129
3.6 Crystallization dynamics: Disproportionation and aging....................................................... 130
3.7 Crystallization dynamics application: fats and oils ................................................................ 131
2
, 3.8 Summary................................................................................................................................ 134
4 Lecture 14/09 .................................................................................................................................... 134
4.1 Introduction: Multidomain products and edible coatings and barriers ................................ 134
4.3 Migration in liquids................................................................................................................ 135
4.4 Migration in solids ................................................................................................................. 137
4.4 Avoid transfer in multidomain foods .................................................................................... 139
4.5 Matching the properties........................................................................................................ 139
4.6 Reducing the transfer ............................................................................................................ 141
4.7 Influence of the structure of composite films and defects ................................................... 143
4.8 Components to use for making edible films.......................................................................... 147
5 Lecture 18/09 & 21/09 ...................................................................................................................... 147
5.1 What are emulsions ? ............................................................................................................ 147
5.2 Characteristics, formulation and stability ............................................................................. 148
5.3 Preparation methods............................................................................................................. 159
5.4 Functional emulsions and potential applications in foods .................................................... 168
5.5 Ice cream ............................................................................................................................... 169
6 Lecture 25/09 .................................................................................................................................... 177
6.1 (Bio) Polymers ....................................................................................................................... 177
6.2 Polymer science principles .................................................................................................... 178
6.3 Water polymer interactions .................................................................................................. 179
6.4 Phase behavior ...................................................................................................................... 180
6.5 Mechanical properties and controlled gelling in mixed gels ................................................. 184
7 Lecture 28/09 .................................................................................................................................... 187
7.1 Summary lecture 25/09 ......................................................................................................... 187
7.2 Extrusion: A thermodynamical process ................................................................................. 188
3
, Reader
1 Food Structures, Building Blocks and Food Properties
1.1 Introduction to food structure
Food products
- Many food products have soft solid appearance
(in this course)
- Many products contain high concentrations of
protein, carbohydrates or oil
- Product behavior is difficult to study, to control
and to predict -> focus on generic behavior
- Properties determined by
• Composition
• Structure
Types of structures
Anisotropic = mechanical properties are different in two directions
-> Different properties that depend on the orientation
Isotropic = emulsion in which the mechanical properties are
homogeneous
-> Equal properties in all directions -> (network of) particles in solution
a. highly fibrous structure -> alignment already at the level of the
size of proteins
d. Particles are a simple emulsion in solution
e. Interaction between bubbles/particles -> larger effect
(thickening)
f. Particles/bubbles are aligned -> more solid
• Different if you break or cut it
Composition – three main components
- Not (well) miscible -> they normally disperse into each other
- By making use of different techniques we combine the ingredients to
make different food products
- Other main ingredient is air
4
Reader ........................................................................................................................................................... 4
1 Food Structures, Building Blocks and Food Properties ......................................................................... 4
1.1 Introduction to food structure .................................................................................................. 4
1.2 Building blocks ........................................................................................................................... 5
1.3 Phase and state diagrams.......................................................................................................... 8
1.4 Glass transition .......................................................................................................................... 9
1.5 Rules for estimation of food properties and effect of structure on some food properties .... 10
1.6 Summary.................................................................................................................................. 10
2 The State Diagram and the Glass Transition ....................................................................................... 11
2.1 The states of foods .................................................................................................................. 11
2.2 Gases, vapors and liquids and vapor ....................................................................................... 11
2.3 Diagrams .................................................................................................................................. 13
2.4 The glass transition .................................................................................................................. 17
2.5 Semi-crystallinity, chemical and physical crosslinking ............................................................ 21
2.6 Some examples........................................................................................................................ 23
2.7 Summary.................................................................................................................................. 33
3 Crystallization and Matrix Formation .................................................................................................. 35
3.1 Introduction ............................................................................................................................. 35
3.2 Crystals .................................................................................................................................... 35
3.3 Food structure from crystals ................................................................................................... 36
3.4 Crystallization and the state diagram ...................................................................................... 37
3.5 Crystallization dynamics .......................................................................................................... 39
3.6 Structure stability and evolution ............................................................................................. 42
3.7 Freezing and thawing .............................................................................................................. 43
4 Barrier Technology in Food Products .................................................................................................. 54
4.1 Introduction ............................................................................................................................. 54
4.2 Kinetics: Diffusion .................................................................................................................... 59
4.3 Prevention of defects in barrier films...................................................................................... 65
4.4 Preparation procedures........................................................................................................... 67
4.5 Mechanical behavior ............................................................................................................... 70
1
, 4.6 Wetting behavior ..................................................................................................................... 70
5 Emulsions: Principles and Preparation ................................................................................................ 73
5.1 Introduction ............................................................................................................................. 73
5.2 Emulsions-based products, types of emulsions and their applications .................................. 73
5.3 Interfacial tension, interfacial energy and Laplace pressure .................................................. 74
5.4 Physical stability of emulsion .................................................................................................. 75
5.5 Physical characterization of emulsions ................................................................................... 79
5.6 Making emulsions using flow fields......................................................................................... 82
6 Structuring of biopolymer products .................................................................................................... 91
6.1 Introduction to structuring biopolymer products ................................................................... 91
6.2 The role of polymer chain structure and length in polymer properties ................................. 91
6.3 Water binding in biopolymer mixtures ................................................................................... 92
6.4 Phase behavior of polymer-solvent mixtures – Thermodynamic composition ...................... 95
6.5 Phase behavior of biopolymer mixtures – Equilibrium composition ...................................... 97
6.6 Rheological properties of (semi-solid) food products – Kinetic composition ......................... 98
6.7 Processing of dense biopolymer systems.............................................................................. 102
Lectures ..................................................................................................................................................... 108
2 Lecture 07/09 .................................................................................................................................... 108
2.1 Recap lecture 1 ...................................................................................................................... 108
2.2 States in foods ....................................................................................................................... 109
2.3 The glass transition ................................................................................................................ 110
2.4 The use of state diagrams to analyze processes ................................................................... 112
2.5 Example: two types of candy................................................................................................. 114
2.6 Example: baking bread .......................................................................................................... 116
2.7 Summary................................................................................................................................ 116
3 Lecture 11/09 .................................................................................................................................... 118
3.1 Crystallization: Thermodynamics and state diagrams........................................................... 118
3.2 Crystallization: Cryostabilisers and cryoprotectants ............................................................. 123
3.3 Crystallization application: freeze drying .............................................................................. 125
3.4 Crystallization dynamics: Nucleation and crystal growth ..................................................... 126
3.5 Crystallization dynamics application: Freeze alignment and structuring.............................. 129
3.6 Crystallization dynamics: Disproportionation and aging....................................................... 130
3.7 Crystallization dynamics application: fats and oils ................................................................ 131
2
, 3.8 Summary................................................................................................................................ 134
4 Lecture 14/09 .................................................................................................................................... 134
4.1 Introduction: Multidomain products and edible coatings and barriers ................................ 134
4.3 Migration in liquids................................................................................................................ 135
4.4 Migration in solids ................................................................................................................. 137
4.4 Avoid transfer in multidomain foods .................................................................................... 139
4.5 Matching the properties........................................................................................................ 139
4.6 Reducing the transfer ............................................................................................................ 141
4.7 Influence of the structure of composite films and defects ................................................... 143
4.8 Components to use for making edible films.......................................................................... 147
5 Lecture 18/09 & 21/09 ...................................................................................................................... 147
5.1 What are emulsions ? ............................................................................................................ 147
5.2 Characteristics, formulation and stability ............................................................................. 148
5.3 Preparation methods............................................................................................................. 159
5.4 Functional emulsions and potential applications in foods .................................................... 168
5.5 Ice cream ............................................................................................................................... 169
6 Lecture 25/09 .................................................................................................................................... 177
6.1 (Bio) Polymers ....................................................................................................................... 177
6.2 Polymer science principles .................................................................................................... 178
6.3 Water polymer interactions .................................................................................................. 179
6.4 Phase behavior ...................................................................................................................... 180
6.5 Mechanical properties and controlled gelling in mixed gels ................................................. 184
7 Lecture 28/09 .................................................................................................................................... 187
7.1 Summary lecture 25/09 ......................................................................................................... 187
7.2 Extrusion: A thermodynamical process ................................................................................. 188
3
, Reader
1 Food Structures, Building Blocks and Food Properties
1.1 Introduction to food structure
Food products
- Many food products have soft solid appearance
(in this course)
- Many products contain high concentrations of
protein, carbohydrates or oil
- Product behavior is difficult to study, to control
and to predict -> focus on generic behavior
- Properties determined by
• Composition
• Structure
Types of structures
Anisotropic = mechanical properties are different in two directions
-> Different properties that depend on the orientation
Isotropic = emulsion in which the mechanical properties are
homogeneous
-> Equal properties in all directions -> (network of) particles in solution
a. highly fibrous structure -> alignment already at the level of the
size of proteins
d. Particles are a simple emulsion in solution
e. Interaction between bubbles/particles -> larger effect
(thickening)
f. Particles/bubbles are aligned -> more solid
• Different if you break or cut it
Composition – three main components
- Not (well) miscible -> they normally disperse into each other
- By making use of different techniques we combine the ingredients to
make different food products
- Other main ingredient is air
4
