Pectins and Their Manipulation (Sheffield Biological Siences)

Contents......Page 10
1.1 Introduction......Page 14
1.2 Chemical structure of pectins......Page 15
1.2.1 Structural elements......Page 19
1.3 Chemical stability of pectins......Page 31
1.4 Pectins as food ingredients......Page 32
1.5 Pectins as 'bioactive' compounds......Page 34
1.6 Methodology in pectin research......Page 35
References......Page 38
2.2 An overview of cell wall models......Page 43
2.3 Experimental approaches to the study of covalent crosslinks between polymers......Page 44
2.5 Historical perspective on crosslinks to pectins......Page 46
2.6 Evidence in 1973 for a xyloglucan–pectin linkage and a pectin–protein linkage......Page 47
2.7 Testing the 1973 cell wall model......Page 48
2.8 Recent evidence for the existence of some crosslinking between pectin and hemicellulose......Page 51
2.9 Ester linkages between pectin and other polymers......Page 54
2.10 Recent evidence for the existence of some crosslinking between pectin and extensin......Page 55
2.11 Considering crosslinks and cell wall dynamics......Page 57
2.12.1 Covalent interactions......Page 58
2.12.2 Noncovalent interactions......Page 59
References......Page 60
3.1 Introduction......Page 65
3.3 Subcellular location of pectin synthesis......Page 66
3.4 Synthesis of the nucleotide-sugar substrates required for pectin synthesis......Page 72
3.4.1 Undine diphosphate-α-D-galacturonic acid (UDP-GalA)......Page 75
3.4.2 Undine diphosphate-β-L-arabinose (UDP-L-Ara)......Page 76
3.4.3 Undine diphosphate-β-L-rhamnose (UDP-L-Rha)......Page 77
3.4.4 Undine diphosphate-α-D-galactose (UDP-Gal)......Page 78
3.4.5 Undine diphosphate-α-D-glucuronic acid (UDP-GlcA)......Page 79
3.4.7 Guanosine diphosphate-β-L-fucose (GDP-Fuc)......Page 81
3.4.8 Undine diphosphate-α-D-apiose (UDP-apiose)......Page 83
3.4.10 XXX-Kdo, XXX-Dha and XXX-aceric acid......Page 84
3.5 Glycosyltransferases involved in pectin biosynthesis......Page 85
3.5.1 Synthesis of homogalacturonan......Page 86
3.5.2 Synthesis of substituted homogalacturonans......Page 91
3.5.3 Synthesis of rhamnogalacturonan I (RG-I)......Page 95
3.6 Future directions and resources for studying pectin biosynthesis......Page 100
References......Page 101
4.1 Introduction......Page 112
4.2.1 Gel structure......Page 116
4.2.2 Mechanisms for the deformation of gels under stress......Page 117
4.2.3 Single-chain mechanics......Page 118
4.2.4 Junction zones under mechanical stress......Page 120
4.3.1 Chain conformation......Page 124
4.3.2 Single pectic chains under tension......Page 126
4.3.3 Chain aggregation and the potential formation of junction zones......Page 128
4.3.4 Covalent crosslinks......Page 131
4.4 Conclusions: pectic gels under stress......Page 134
References......Page 136
5.1 Introduction to pectin biology......Page 144
5.2 Tools and approaches for the analysis of pectins in planta......Page 145
5.3.1 Pectic polysaccharides and matrix properties......Page 147
5.3.2 Pectin and cell wall architecture......Page 148
5.4.1 Pectins, metabolism and signalling......Page 151
5.4.3 Cell expansion......Page 152
5.4.4 Cell differentiation......Page 155
5.4.5 Pectins and the intercellular matrix: cell adhesion......Page 156
5.5 Prospects......Page 158
References......Page 159
6.2 Pectin-degrading enzymes......Page 163
6.2.1 Pectinesterase......Page 166
6.2.2 Polygalacturonase......Page 167
6.2.3 Pectate lyase......Page 168
6.2.4 Pectin acetylesterase......Page 169
6.2.6 Rhamnogalacturonase and minor pectinases......Page 170
6.3.1 Fruit ripening......Page 171
6.3.3 Growth......Page 175
6.4 Functional analysis of pectinases......Page 176
6.5 Application of gene silencing techniques......Page 177
6.6 Use of mutants......Page 179
6.7 Conclusion and prospects......Page 180
References......Page 181
7.1 Introduction......Page 187
7.2 Polygalacturonases......Page 188
7.2.1 Exopolygalacturonases......Page 192
7.2.3 Endopolygalacturonases......Page 194
7.3 Pectate and pectin lyases......Page 203
7.3.2 Endo-pectate lyases......Page 206
7.3.3 Pectin lyases......Page 210
7.4 Heterogalacturonases......Page 215
7.4.1 Endo-acting rhamnogalacturonan-degrading enzymes......Page 216
7.4.2 Rhamnogalacturonan rhamnohydrolase......Page 220
7.5 Pectic esterases......Page 221
7.5.1 Pectin methylesterases......Page 222
7.5.2 Pectin homogalacturonan acetylesterases......Page 224
7.5.3 Rhamnogalacturonan acetylesterases......Page 226
References......Page 228
8.1.1 Raw materials......Page 235
8.1.2 Production process for high-ester pectin......Page 236
8.1.4 Standardization......Page 237
8.2.1 'Pectin' as defined by national and international authorities......Page 238
8.2.2 Vocabulary of terminology and concepts......Page 239
8.3.1 Composition......Page 240
8.3.2 Acidic properties......Page 241
8.3.5 Parameters influencing thickening and gelling......Page 242
8.4.1 Making an aqueous solution......Page 245
8.4.2 Mixing pectin with other ingredients......Page 246
8.4.3 Making gels......Page 247
8.5.1 Sweet, fruit-flavored gels......Page 248
8.5.2 Use with fermented or acidified milk......Page 249
8.5.5 Pharmaceutical uses......Page 251
References......Page 252
A......Page 255
C......Page 256
F......Page 257
G......Page 258
M......Page 259
P......Page 260
S......Page 261
X......Page 262
Z......Page 263