Table of Contents
Chapter 1 Biosynthesis, Localisation, and Function of Pectins in Plants 8
1.1 Pectin biosynthesis. 8
1.2 Localisation of pectins in plants. 11
1.3 Pectin functions in plants. 13
Chapter 2 Pectin Structure. 25
2.1 Introduction.. 25
2.2 Galacturonans. 28
2.2.1 Homogalacturonans. 28
2.2.2 Galacturonans substituted with more or less complex side-chains. 31
2.3 Rhamnogalacturonan I 35
2.3.1 Rhamnogalacturonan I backbone. 35
2.3.2 Rhamnogalacturonan I side-chains. 37
2.3.3 Side-chain intra- and inter-molecular distribution.. 39
2.4 Connection between pectin domains. 40
2.5 Conclusions. 42
Chapter 3 Pectin Degrading Enzymes. 50
3.1 Introduction.. 50
3.2 Homogalacturonan-degrading enzymes. 51
3.2.1 Polygalacturonases (PG). 52
3.2.2 Pectin and pectate lyases. 55
3.2.3 Pectin methylesterases (PMEs). 57
3.2.4 Pectin acetylesterases (PAE). 59
3.3 Rhamnogalacturonan-degrading enzymes. 61
3.3.1 Rhamnogalacturonan-hydrolases. 61
3.3.2 Rhamnogalacturonan-lyases. 62
3.3.3 Rhamnogalacturonan-acetylesterase. 64
3.4 Side-chain degrading enzymes. 64
3.4.1 Arabinanases and α-arabinofuranosidases. 64 3.4.2 Galactanases and β-galactosidases. 66
3.4.3 Feruloylesterases. 68
3.5 Synergistic action of pectin degrading enzymes. 69
3.6 Conclusion.. 70
Chapter 4 Isolation and Characterisation of Pectin.. 80
4.1 Introduction.. 80
4.2 Extraction of pectin.. 82
4.2.1 Conventional extraction methods. 83
4.2.2 Enzymatic extraction.. 84
4.2.3 Microwave-assisted extraction.. 84
4.2.4 Ultrasonic extraction.. 85
4.2.5 Sub-critical water extraction/accelerated solvent extraction.. 85
4.3 Characterisation of pectin.. 86
4.3.1 Phenol-sulfuric acid/total carbohydrate assay. 86
4.3.2 Galacturonic acid content and degree of methyl esterification (DM). 87
4.3.3 Sugar composition.. 89
4.3.4 Molar mass and molar mass distribution.. 91
4.3.5 Intrinsic viscosity. 94
4.3.6 Rheology. 96
4.4. Conclusions. 98
Chapter 5 Emulsification Properties of Pectin.. 107
5.1. Introduction.. 107
5.2. Role of structural elements on the interfacial activity. 109
5.2.1 The role of protein.. 109
5.2.2 The role of acetyl and methyl groups. 111
5.2.3 The role of molecular weight and side chains. 112
5.3. Phenomenology of pectin adsorption at the oil-water interface. 115
5.4. Conclusions. 121
Chapter 6 Edible Films and Coatings with Pectin.. 125
6.1. Introduction.. 125
6.2. Edible films and coatings from pectins: elaboration and physical properties. 130
6.3. Pectin-based films and coatings in food preservation.. 139
6.4. Conclusions. 150
Chapter 7 Pectin Gelation and its Assembly into Functional Materials 159
7.1 Introduction.. 159
7.1.1 A soft matter exemplar. 159
7.1.2 Evolved pectin networks. 160
7.1.3 Current human exploitation.. 161
7.1.4 Unlocking the potential 161
7.2 Making pectin gels. 162
7.2.1 Different types of junction zones. 162
7.2.2 Different assembly procedures. 167
7.2.3 Practical top-tips for making gels. 171
7.3 Measuring gel properties. 174
7.4 Modelling mechanical properties. 179
7.5 Conclusions. 182
Chapter 8 Digestion and Metabolism of Pectin.. 192
8.1. Introduction.. 192
8.1.1 Pectin as a source of soluble fibre and influence on digestion.. 192
8.1.2 Sources of pectin.. 193
8.1.3 Processed vs. whole food sources. 195
8.2. Digestion..
