Second Edition
A detailed survey of a variety of natural colorants and their different applications including textiles, polymers, and cosmetics
Colorants describe a wide range of materials such as dyes, pigments, inks, paint, or chemicals, which are used in small quantities but play an important role in many products such as textiles, polymers, food, and cosmetics. As the effects of climate change begin to be felt, there has been a shift in focus in the field to renewable resources and sustainability, and an interest in the replacement of oil-based products with greener substitutions. As the push to adopt natural resources grows, there have been significant developments in the research and application of natural colorants as a step in the transition to a bio-based economy.
The second edition of Handbook of Natural Colorants provides a detailed introduction to natural colorants in a marriage of theory and practice, from seed of plant to consumer demand. Presenting a wide range of viewpoints, the book briefly discusses the history of coloration technology and the current position of natural colorants before highlighting detailed information on regional plant source availability, colorant production and properties, as well as analytical methods for isolation, identification, and toxicity aspects. It also presents key applications in technical use and consumer products, including the use of natural colorants in textiles, hair dyeing, printing, and packaging. Finally, the text considers environmental and economic aspects of natural colorants.
Handbook of Natural Colorants is a useful reference for dyers, textile producers, and researchers in the evolving field of sustainable chemistry, environmental sciences, agricultural sciences, and polymer sciences.
Table of Contents
List of Contributors xxi
Series Preface xxv
Preface xxvii
I Historical Development 1
1 History of Natural Dyes in the Ancient Mediterranean Civilization 3
Maria J. Melo
1.1 Introduction 3
1.1.1 Ancient Mediterranean World 3
1.1.2 Dyes from Antiquity 4
1.1.3 Unveiling the Secrets of Ancient Dyes with Modern Science 7
1.2 Ancient Reds 7
1.2.1 Anthraquinone Reds 7
1.2.2 Redwoods 10
1.2.3 Flavylium/Anthocyanin Reds 12
1.2.3.1 Equilibria in solution 13
1.3 Ancient Blues 14
1.3.1 Indigo Blues 14
1.3.2 Anthocyanin Blues 15
1.4 Ancient Purples 16
1.4.1 Tyrian Purple: Real Purple from Sea Snails 16
1.4.2 Orchil Purples 18
1.4.3 Folium 18
1.5 Ancient Yellows 20
1.5.1 Flavonoid Yellows 20
1.5.2 Carotenoid Yellows 21
1.5.3 Chalcone and Aurone Yellows 22
Acknowledgements 22
References 22
2 Colors in Civilizations of the World and Natural Colorants: History under Tension 27
Dominique Cardon
2.1 Introduction 27
2.2 The Triumph of Mauveine: Synthetic Fulfillment of the Antique Purplemania 28
2.3 Blue: From Kingly Regional to Globally Democratic 29
2.4 Red and Yellow: From Micro to Macro Scales 29
2.5 What Is the Future for Natural Colorants in the Dawning Era of Renewable Resources? 30
Acknowledgement 31
References 31
3 History of Natural Dyes in North Africa_Egypt 33
Harby Ezzeldeen Ahmed
3.1 Introduction 33
3.2 Natural Dyes in Pharaonic Textiles 34
3.3 Dyeing Techniques 34
3.4 Dye Sources 34
3.4.1 Woad 35
3.4.2 Indigo 35
3.4.3 Red 35
3.4.4 Yellow 36
3.4.5 Black 36
3.4.6 Brown 36
3.4.7 Green 36
3.4.8 Purple 36
3.5 Dyeing in Coptic Textiles 36
3.6 Wool- Dyed Fabric with Natural Dye 38
3.7 Dyes in Islamic Textiles 38
3.8 Mordants 40
References 40
II Natural Colorants in Different Regions of the World 43
4 Sources for Natural Colorants in Europe 45
Thomas Bechtold, Tung Pham and Avinash P. Manian
4.1 Introduction 45
4.2 Cultivation 46
4.2.1 Potential European Dye Plants Yesterday and Now 46
4.2.2 Modern Cultivation Methods - General Facts 47
4.2.3 Blue- Dye Plants 48
4.2.4 Red- Dye Plants 49
4.2.5 Yellow- Dye Plants 49
4.2.6 Brown- Dye Plants 52
4.2.7 Production of Dye Extracts 54
4.3 Natural Colorants from Agro- Food Residues 55
4.4 Natural Colorants from Forestry and Timber Industry 56
4.5 Relevant Examples for the Application 57
4.6 Conclusions, Discussion, and Summary 58
Acknowledgement 58
References 59
5 Dyes in South America 63
Veridiana Vera de Rosso and Adriana Zerlotti Mercadante
5.1 Introduction 63
5.2 Annatto 65
5.3 Turmeric 67
5.4 Marigold 68
5.5 Cochineal and Carmine 69
Acknowledgements 71
References 71
6 Natural Dyes in Eastern Asia (Vietnam and Neighboring Countries) 75
Tung Pham and Thomas Bechtold
6.1 Introduction 75
6.2 Annatto (Bixa orellana L., Family Bixaceae) 75
6.3 Tea (Camellia sinensis (L.) Kuntze, Family Theaceae) 77
6.4 Umbrella Tree (Terminalia catappa L., Family Combretaceae) 77
6.5 Mackloeur (Diospyros mollis L. Griff, Family Ebenaceae) 78
6.6 Indigo (Indigofera L., Family Fabaceae) 79
6.6.1 Indigofera tinctoria L. 79
6.6.2 Indigofera galegoides dc 80
6.6.3 Strobilanthes cusia (Baphicacanthus) 80
6.7 Henna (Kok Khan or Khao Youak in Laos) (Lawsonia spinosa L., Family Lythraceae) 80
6.8 Nacre (African Mahogany, Khaya senegalensis, Family Meliaceae) 81
6.9 Sappan Wood (Caesalpinia sappan L., Family Fabaceae) 81
6.10 Japanese Pagoda Tree Flowers (Sophora japonica L., Family Leguminosae) 82
6.11 Turmeric (Curcuma longa L., Family Zingiberaceae) 82
6.12 Sapodilla (Manilkara zapota L. or Achras zapota, Family Sapotaceae) 82
6.13 Betel (Piper betel L., Family Piperaceae) 83
6.14 Eucalyptus (Eucalyptus, Family Myrtaceae) 83
6.15 Caesalpinia Yellow (Caesalpinia pulcherrima L., Family Fabaceae) 83
6.16 Brow- Tuber; Yam (Dioscorea cirrhosa Lour, Family Dioscoreaceae) 83
6.17 Others 84
Acknowledgement 84
References 84
7 Sources for Natural Colorants in China 89
Ren-Cheng Tang
7.1 Introduction 89
7.2 Sophora japonica Yellow 92
7.3 Turmeric 93
7.4 Gardenia Yellow 93
7.5 Emodin 93
7.6 Baicalin 94
7.7 Berberine 94
7.8 Henna 94
7.9 Monascus Red 95
7.10 Madder 95
7.11 Sorghum Red 95
7.12 Mulberry Red 96
7.13 Shikonin 96
7.14 Indigo 96
7.15 Condensed Tannins 97
7.16 Tea Polyphenols 98
7.17 Gallnut 99
References 99
8 Sources, Application, and Analysis of Natural Colorants: An Indian Perspective 103
Prof. (Dr.) Ashis Kumar Samanta and Prof. (Dr.) Deepali Singhee
8.1 Introduction 103
8.2 Natural Dyes in India 104
8.2.1 History 104
8.2.2 Traditional Processes of Dyeing with Natural Dyes in Different Parts of India 105
8.2.3 Sources of Natural Dyes in India 106
8.2.4 Use of Some Natural Dyes in Traditional Textiles of India 107
8.3 Details of Some Dye Sources and Their Application in India 109
8.3.1 Turmeric 109
8.3.2 Pomegranate 111
8.3.3 Flame of Forest 114
8.3.4 Marigold 116
8.3.5 Safflower 118
8.3.6 Annatto 120
8.3.7 Madder 123
8.3.8 Indian Mulberry 125
8.3.9 Arjuna 127
8.3.10 Sappanwood 130
8.3.11 Eucalyptus 132
8.3.12 Catechu 134
8.3.13 Gallnut 137
8.3.14 Myrobolan 140
8.3.15 Lac 142
8.3.16 Indigo 145
References 147
9 Natural Dye Gardens in North America 161
Wendy Weiss and Thomas Bechtold
9.1 Introduction 161
9.2 Participants 162
9.3 Education 163
9.4 Motivation to Work with Natural Dye 166
9.5 Plant List - Cultivated Plants 166
9.6 Chemical Background of Most Relevant Plants 168
9.7 Plant List - Foraged Plants 172
9.8 Plants with Indigotin 172
9.9 Importance of the Fibershed Movement 173
9.10 Educational and Community Gardens 174
9.11 Mexico 177
9.12 Canada 177
9.13 Future Research 178
References 178
Notes 179
III Colorant Production and Properties 181
10 Chlorophylls 183
María Roca
10.1 Introduction 183
10.2 Chemical Structures and Physicochemical Properties 184
10.3 Chlorophylls as Colorants 187
10.4 New Trends in the Use of Chlorophylls as Colorants 189
10.5 Stability and Analysis 190
10.6 Toxicological and Safety Aspects 191
References 192
11 Indigo - Production and Properties 195
Philip John and Luciana Gabriella Angelini
11.1 Introduction 195
11.2 Agronomy 196
11.2.1 Isatis 196
11.2.1.1 Developmental Stages and Climate and Soil Crop Requirements 197
11.2.1.2 Rotation 201
11.2.1.3 Soil Tillage and Seed Sowing 202
11.2.1.4 Weeds, Pests, and Diseases 203
11.2.1.5 Fertilizers and Irrigation 204
11.2.1.6 Harvesting and Yields 205
11.2.1.7 Seed Production 207
11.2.1.8 Isatis indigotica Compared with Isatis tinctoria 208
11.2.2 Persicaria 209
11.2.2.1 Introduction 209
11.2.2.2 Developmental Stages 211
11.2.2.3 Sowing, Harvesting, and Yield 211
11.2.2.4 Weeds, Pests, and Diseases 216
11.2.2.5 Fertilizer and Irrigation Requirement 216
11.2.2.6 Seed Production 217
11.2.3 Indigofera 217
11.3 Methods of Determining Indigo 219
11.4 Precursors in the Plants 222
11.5 Direct Dyeing with Indican 227
11.6 Indigo Formation 227
11.7 Extraction Procedures 229
11.7.1 Traditional Process Using Crushed Leaf Material 229
11.7.1.1 Isatis 229
11.7.1.2 Persicaria 230
11.7.2 Steeping in Water 231
11.7.2.1 Indigofera 232
11.7.2.2 Isatis 234
11.7.2.3 Persicaria 239
11.8 Purity of Natural Indigo 240
11.8.1 Purification by Sublimation 241
11.8.2 Impurities in Natural Indigo 242
Acknowledgements 245
References 245
12 Anthocyanins: Revisiting Nature’s Glamorous Palette 251
Maria J. Melo, Fernando Pina, Natércia Teixeira and Claude Andary
12.1 Chemical Basis 251
12.1.1 Chemical Structures 251
12.1.2 Equilibria in Solution 253
12.1.3 Kinetics 254
12.1.4 Color and Color Stability 254
12.1.5 Anthocyanins as Antioxidants 258
12.2 Natural Sources and Applications for Anthocyanins 259
12.2.1 Plants Sources, Content, Influencing Parameters 259
12.2.2 Food Colorants 260
12.2.3 Other Uses 261
12.2.4 Examples of Commercial Products and Processing 262
References 263
Appendix 1 267
A1.1 Multi-Equilibria in Acidic and Basic Media 267
A1.2 Measuring the Equilibria Constants 269
13 Natural Colorants - Quinoid, Naphthoquinoid, and Anthraquinoid Dyes 271
Goverdina C. H. Derksen and Thomas Bechtold
13.1 Introduction 271
13.2 Benzoquinone Dyes 271
13.3 Diaryloylmethane Dyes 273
13.4 Naphthoquinone Dyes 273
13.4.1 Lawson (2- hydroxy- 1,4- naphthoquinone, CI Natural Orange 6) 274
13.4.1.1 Properties and Use 274
13.4.1.2 Agricultural Aspects 276
13.4.2 Juglone (5- hydroxy- 1,4- naphthoquinone, CI Natural Brown 7) 278
13.5 Anthraquinone Dyes 279
13.5.1 Main Components Emodin and Chrysophanol - Rheum and Rumex Species 279
13.5.2 Main Components Alizarin and/or Pseudopurpurin/Purpurin 281
13.5.2.1 Plant Sources 281
13.5.2.2 Madder CI Natural Red 8 282
References 294
14 Natural Colorants from Lichens and Mushrooms 317
Riikka Räisänen
14.1 Use of Lichen and Mushroom Colorants in History 317
14.2 Cultivation of Lichens and Mushrooms 318
14.3 Colorant Structures in Lichens and Mushrooms 319
14.3.1 Lichen Dyes: Orchils and Litmus 321
14.3.2 Yellowish, Brownish, and Reddish Colorants from Lichen 322
14.3.3 Blue Terphenylquinones from Mushrooms 322
14.3.4 Anthraquinones 324
14.3.4.1 Bloodred Webcap (Cortinarius sanguineus) 324
14.3.5 Other Colorants of Fungi 326
14.3.5.1 Yellows from Grevillines 326
14.3.5.2 Yellow and Orange Colors from Pulvinic Acid Derivatives 326
14.3.5.3 Brown from Badiones 326
14.4 Stability of Lichen and Mushroom Colorants 326
14.5 New Approaches to Lichen and Fungal Colorants 327
References 328
15 Focus on Tannins 333
Riitta Julkunen-Tiitto and Hely Häggman
15.1 Introduction 333
15.2 Chemical Structure, Biosynthesis, and Degradation 335
15.3 Properties of Tannins 338
15.4 Chemical Activities of Tannins 340
15.5 Analysis of Tannins 340
15.5.1 Sample Preservation 340
15.5.2 Extraction and Purification 340
15.5.3 Quantification of Tannins 341
15.6 Use, Toxicology, and Safety Aspects of Tannins 342
References 345
16 Carotenoid Dyes - Properties and Production 351
U. Gamage Chandrika
16.1 Introduction 351
16.1.1 Occurrence of Carotenoids 351
16.1.2 Chemistry of Carotenoids 351
16.1.3 Chemical Characteristics of Natural Carotenoids 352
16.2 Properties and Functions of Carotenoids 354
16.2.1 Carotenoids’ Role as Pro- vitamin A 354
16.2.2 Use of Carotenoids as Markers of Dietary Practices 356
16.2.3 Carotenoids as Antioxidants 356
16.2.4 Carotenoids in the Macular Region of the Retina 357
16.2.5 Carotenoids as Anticancer Agents 357
16.2.6 Carotenoids as Natural Colorants 357
16.3 General Procedure for Carotenoid Analysis 357
16.3.1 Sampling 359
16.3.2 Extraction 359
16.3.3 Saponification of Carotenoids 359
16.3.4 Chromatographic Separation 359
16.3.5 Chemical Tests 361
16.3.6 Detection and Identification of Carotenoids 361
16.3.7 Quantification of Carotenoids 362
16.4 Problems in Carotenoid Analysis 362
16.5 Factors Influencing Carotenoid Composition in Plant Sources 363
16.5.1 Stage of Maturity 363
16.5.2 Cultivar or Varietal Differences 363
16.5.3 Climatic or Geographic Effects 364
16.5.4 Post- Harvest Storage and Packing 364
16.5.5 Changes in Processing/Cooking 364
16.5.6 Effect of Agrochemicals 366
References 366
17 Flavonoids as Natural Pigments 371
M. Monica Giusti, Gonzalo Miyagusuku-Cruzado and Taylor C. Wallace
17.1 Introduction 371
17.2 Role of Localized Flavonoids in the Plant 372
17.3 General Flavonoid Chemical Structure 372
17.4 Biosynthesis of Flavonoids 373
17.5 Anthocyanins as Natural Colorants 373
17.5.1 Structure 375
17.5.2 Structural Transformation and pH 376
17.5.3 Temperature 377
17.5.4 Oxygen and Ascorbic Acid 377
17.5.5 Light 378
17.5.6 Enzymes and Sugars 379
17.5.7 Sulfur Dioxide 379
17.5.8 Co- Pigmentation and Metal Complexation 380
17.6 Other Flavonoids as Natural Colorants 381
17.6.1 Yellow Flavonoid Pigments 381
17.6.2 Tannins 381
17.6.3 Anthocyanin- Derived Pigments: Pyranoanthocyanins 382
17.7 Therapeutic Effects of Flavonoids in the Diet 382
17.8 The Use of Flavonoids as Food Colors in the US and EU 383
References 384
18 Natural Colorants from Fungi 391
Cassamo U. Mussagy, Fernanda de Oliveira and Valeria C. Santos-Ebinuma
18.1 Introduction 391
18.2 Types of Fungi Colorants 392
18.3 Fungal Producer of Colorants 394
18.4 Bioprocess 395
18.4.1 Biosynthesis Pathway 395
18.4.2 Production and Extraction Process 400
18.5 Toxicity 404
18.6 Industrial Application of Fungi Colorants 406
18.7 Conclusion 407
References 407
19 Natural Colorants from Cyanobacteria and Algae 417
Laurent Dufossé
19.1 Introduction 417
19.2 Phycobiliproteins from Cyanobacteria 418
19.2.1 Structural Characteristics of Phycobiliproteins 420
19.2.2 Food Grade Phycobiliproteins 422
19.2.3 Future Trends 422
19.3 Pigments from Microalgae 422
19.3.1 β- Carotene from the Microalga Dunaliella, Salty but Effective! 423
19.3.1.1 β- Carotene from Microalgae 423
19.3.1.2 Dunaliella Species for Carotenoids 424
19.3.2 Why Carotenoids from Dunaliella? 424
19.3.2.1 Natural vs. Synthetic β- Carotene 424
19.3.2.2 Applications of β- Carotene 424
19.3.2.3 Advantages of Carotenoids Production from Dunaliella 425
19.3.2.4 Process for Production of β- Carotene from Dunaliella 425
19.3.2.5 Companies Producing Dunaliella 425
19.3.2.6 Marketed Products of β- Carotene 426
19.3.3 Haematococcus for Astaxanthin, the Red Gold Rush 426
19.3.3.1 Advantages of Astaxanthin over Other Carotenoids 427
19.3.3.2 Astaxanthin as Nutraceutical 427
19.3.3.3 Astaxanthin as Antioxidant 427
19.3.3.4 Astaxanthin for Health 428
19.3.3.5 Astaxanthin for Salmon and Trout Feeds 428
19.3.3.6 Astaxanthin for Humans 429
19.3.3.7 Production System for Haematococcus 429
19.3.3.8 Companies Producing Astaxanthin from Haematococcus 430
19.3.3.9 Astaxanthin- Containing Formulations 431
19.4 Natural Colorants from Macroalgae (e.g., Seaweeds) 431
19.4.1 Biodiversity of Seaweeds 431
19.4.2 Seasonal Variations and Environmental Threats 432
19.4.3 Major Classes of Seaweed Pigments 433
19.4.3.1 Chlorophylls 433
19.4.3.2 Carotenoids 433
19.4.3.3 Phycobiliproteins 434
19.5 Conclusion 434
References 434
20 Biotechnological Production of Microbial Pigments: Recent Findings 439
Vivian Katherine Colorado Gómez, Juan Pablo Ruiz-Sánchez, Alejandro Méndez-Zavala, Lourdes Morales-Oyervides and Julio Montañez
20.1 Introduction 439
20.2 Microbial Pigments Market 440
20.3 Production Strategies 440
20.4 Novel Extraction Technologies for Pigments Recovery 441
20.5 Regulation and Biosynthesis of Microbial Pigments 443
20.6 Strain Engineering Strategies for Pigment Production 446
20.7 Trends in New Microbial Sources of Pigments 448
20.8 Microbial Pigments Applications 449
20.8.1 Solar Cells 449
20.8.2 Therapeutic Application 450
20.8.3 Other Applications 450
20.9 Regulations on Microbial Pigments Use 451
20.10 Conclusions and Future Perspectives 452
References 452
21 Analytical Methods for Characterization and Standardization of Natural Dyes and Pigments 459
Tung Pham, Avinash Manian and Thomas Bechtold
21.1 Introduction 459
21.2 Chemical Analysis - Identification 460
21.3 Quantification by Sum Parameters 463
21.4 Applicatory Tests 464
21.5 Product Performance 465
References 466
22 Wood - From Natural Color Patterns Toward Naturally Altered Color Impressions 469
Martin Weigl-Kuska, Andreas Kandelbauer, Christian Hansmann and Ulrich Müller
22.1 The Color of Wood 469
22.1.1 Wood Chemical Composition 470
22.1.2 Wood Anatomical Appearance 471
22.1.3 Physical Properties of the Wood Surface 472
22.2 Coatings 473
22.3 Dyes 477
22.3.1 Impregnation 477
22.3.1.1 Technology 477
22.3.1.2 Color 479
22.3.1.3 Products 480
22.4 Color Modification 481
22.4.1 Drying 482
22.4.1.1 Basics 482
22.4.1.2 Technology 483
22.4.1.3 Color 484
22.4.2 Steaming 485
22.4.2.1 Basics 485
22.4.2.2 Technology 485
22.4.2.3 Color 486
22.4.3 Thermal Treatment 487
22.4.3.1 Technology 487
22.4.3.2 Color 487
22.4.4 Ammoniation 488
22.4.4.1 Basics 488
22.4.4.2 Color 489
22.4.5 Bleaching 491
22.4.5.1 Basics 491
22.4.5.2 Color 491
22.4.6 Enzymatic Treatment 492
22.4.6.1 Basics 492
22.4.6.2 Laccases 493
22.4.7 Radiation 495
22.4.7.1 Basics 495
22.4.7.2 Color 495
22.4.7.3 Technology 497
22.5 Outlook 498
References 498
23 The Role of Mordants in Fixation of Natural Dyes 507
Avinash P. Manian
23.1 Introduction 507
23.2 Metal Salts 508
23.3 Biomordants 508
23.4 Substrate Pretreatments 508
23.5 No Mordant 509
References 509
24 Textile Coloration with Natural Dyes and Pigments 517
Thomas Bechtold, Tung Pham and Avinash P. Manian
24.1 Introduction 517
24.2 Reasons for Natural Coloration 518
24.3 The Dyestuff-Fiber Interaction 520
24.4 Design of a Dyeing Process 521
24.5 Transfer of a Dyeing Process into Technical Scale 523
24.6 Processes and Resources 524
24.7 Technical Requirements for a Natural Dyestuff 526
24.7.1 Gamut and Color Shade 526
24.7.2 Fastness Criteria 528
24.8 Handling of Natural Dyes in a Technical Dyehouse 530
24.9 Mordanting 531
24.10 Natural Dyes on an Industrial Scale 533
24.10.1 Dyeing Technology - Exhaust Process 533
24.10.2 Hank Dyeing of Woolen Yarn and Production of Woolen Caps 534
24.10.3 Dyeing of Cones in a Yarn Dyeing Machine 534
24.10.4 Dyeing of Cotton Fabric on a Jet Dyeing Machine 535
24.10.5 Fabric Dyeing on a Garment Dyeing Machine 536
24.10.6 Dyeing of Polyamide Tights in a Paddle Dyeing Machine 536
24.10.7 Dyeing Technology - Continuous Dyeing 536
24.11 Conclusion 537
Acknowledgement 538
References 538
25 Hair Coloration with Natural Dyes and Pigments 543
Thomas Bechtold
25.1 Introduction 543
25.2 Human Hair 544
25.3 General Requirements on Hair Dyeing Concepts 544
25.4 Chemical Principles of Dyestuff Binding 546
25.5 Relevant Natural Dyes for Hair Dyeing 546
25.5.1 Naphthoquinone Dyes - Henna and Walnut 546
25.5.1.1 Henna, CI (Color Index) Natural Orange 6 546
25.5.1.2 Juglon, CI Natural Brown 7 547
25.5.2 Indigo 548
25.5.3 Metal Complexes 548
25.5.4 Metal Reaction Dyes 550
25.5.5 Anthraquinoid Dyes 551
25.6 Specialties 551
25.7 Regulations 552
References 552
26 Natural Colorants in the Mass Coloration of Plastics 557
Thomas Bechtold and Tung Pham
26.1 Introduction 557
26.2 Representative Examples 559
Acknowledgement 561
References 561
27 Natural Colorants in Printing/Packaging 563
Thomas Bechtold and Tung Pham
27.1 Introduction 563
27.2 Packaging Films 564
27.3 Film Coloration 567
27.4 Paper Dyeing 568
27.5 Paints 568
Acknowledgement 569
References 569
28 Technical Aspects and Requirements to Produce Natural Colorants - Processes and Product Standardization 573
Thomas Bechtold and Avinash Manian
28.1 Introduction 573
28.2 Sources of Plant Material - Product I 576
28.2.1 Organic Farming 576
28.2.2 Sustainable Farming 576
28.2.3 Native Species 577
28.2.4 Farming for Food or/and Natural Colorants 577
28.2.5 Residual Materials and By- Products 577
28.3 Processing to Dyestuff - Product II 579
28.4 Quality Control and Standardization of a Dye (Product II) 583
28.4.1 Anthocyanins 584
28.4.2 Flavonoids 584
28.4.3 Dye Lakes 585
28.5 Challenges for the Industrial Use of Natural Colorants 585
28.6 Dealing with Sustainability 586
28.7 Conclusions 587
References 587
29 Environmental and Economic Position of Natural Colorants - Energy and Resources Balances, Sustainability, Ecology, and Costs 591
Susanne Geissler and Thomas Bechtold
29.1 Introduction 591
29.2 Dye Plant Production 592
29.3 Dye Extraction and Dyestuff Production 595
29.4 Transportation 596
29.5 Textile Dyeing 596
29.6 Commercial Aspects - Costs 597
29.6.1 Basic Requirements for the Industrial Use of Natural Colorants 598
29.6.1.1 Precondition 1: acceptable costs of natural colorants and dyeing processes 599
29.6.1.2 Precondition 2: feasible cost of process engineering 599
29.6.1.3 Precondition 3: compliance with requested colorfastness properties 599
29.6.1.4 Precondition 4: competitive cost of naturally dyed products 600
29.6.1.5 Precondition 5: security of natural colorant supply 600
29.6.2 Consumer Expectations 600
29.6.3 Market Research for Naturally Dyed Products 601
29.7 Production Costs of Natural Colorant Products 602
29.7.1 Cost Categories 603
29.7.2 Aspects Influencing Production Costs 603
29.8 Prices of Synthetic Dyes - How Much Are Textile Companies Prepared to Pay for Dyes? 605
29.9 Acceptable Production Costs through a Mixed Portfolio (Agricultural Primary Production and Residues from Other Production Processes) 606
29.10 Closed- Loop Economy: Toward a Zero- Emission and Zero- Waste Society 607
29.11 Considerations Concerning the Life Cycle 609
29.12 Conclusion: Aspects Influencing Market Development for Natural Colorants 609
References 610
30 Aspects of Human Toxicology and Consumer Safety 613
Judith Büttler, Thomas Bechtold and Tung Pham
30.1 Introduction 613
30.2 Basic Aspects of Xenobiotic- Induced Toxicity 614
30.3 Toxicological Aspects of Natural Colorants in Food and Medical Applications 615
30.3.1 Risk Assessment 617
30.3.2 Therapeutic Effects (= Risk) 618
30.4 Toxicological Aspects of Natural Colorants in Cosmetics 618
30.4.1 Risk Assessment 619
30.5 Toxicological Aspects of Natural Colorants in Textile Dyeing 619
30.5.1 Plant Extracts 620
30.5.2 Pretreatment Agents and Mordants 621
30.5.3 Wastewater and Antimicrobial Compounds 621
30.5.4 Dyed Products 622
30.6 Test Methods for Toxicity Screening 622
30.6.1 Extract Preparation 624
30.6.2 Cytotoxicity 624
30.6.3 Mutagenicity and Carcinogenicity 625
30.6.4 Antimicrobial Activity 625
30.6.5 Metabolism and In Vivo Animal Bioassays 626
Acknowledgement 626
References 626
Index 629
