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Chocolate Science and Technology, 2nd Edition

Chocolate Science and Technology, 2nd Edition

Emmanuel Ohene Afoakwa

ISBN: 978-1-118-91375-8

Apr 2016, Wiley-Blackwell

536 pages

Description

This second edition provides information on recent advances in the science and technology of chocolate manufacture and the entire international cocoa industry. It provides detailed review on a wide range of topics including cocoa production, cocoa and chocolate manufacturing operations, sensory perception of chocolate quality, flavour release and perception, sugar replacement and alternative sweetening solutions in chocolate production, industrial manufacture of sugar-free chocolates as well as the nutrition and health benefits of cocoa and chocolate consumption.

The topics cover modern cocoa cultivation and production practices with special attention on cocoa bean composition, genotypic variations in the bean, post-harvest pre-treatments, fermentation and drying processes, and the biochemical basis of these operations. The scientific principles behind industrial chocolate manufacture are outlined with detailed explanations of the various stages of chocolate manufacturing including mixing, refining, conching and tempering. Other topics covered include the chemistry of flavour formation and development during cocoa processing and chocolate manufacture; volatile flavour compounds and their characteristics and identification; sensory descriptions and character; and flavour release and perception in chocolate. The nutritional and health benefits of cocoa and chocolate consumption as well as the application of HACCP and other food safety management systems such as ISO 22,000 in the chocolate processing industry are also addressed. Additionally, detailed research on the influence of different raw materials and processing operations on the flavour and other quality characteristics of chocolates have been provided with scope for process optimization and improvement.

The book is intended to be a desk reference for all those engaged in the business of making and using chocolate worldwide; confectionery and chocolate scientists in industry and academia; students and practising food scientists and technologists; nutritionists and other health professionals; and libraries of institutions where agriculture, food science and nutrition is studied and researched.

Preface, xix

Acknowledgements, xxi

About the author, xxiii

1 History, origin and taxonomy of cocoa, 1

1.1 Introduction, 1

1.2 History of cocoa, 2

1.3 Taxonomy of cocoa, 5

1.4 Morphological and varietal characteristics of cocoa, 6

1.4.1 The cocoa plant, 6

1.5 Varietal effects on cocoa bean flavour, 10

1.6 The concept of this book, 15

2 World cocoa production, processing and chocolate consumption pattern, 17

2.1 Introduction, 17

2.2 World production of cocoa, 17

2.3 Major changes in world cocoa trade, 20

2.4 Cocoa yield in producing countries, 22

2.5 World cocoa grindings trends between 2005–2006 and 2014–2015, 23

2.6 World stocks of cocoa beans, 26

2.7 International cocoa price developments, 26

2.8 Cocoa processing trends, 31

2.9 Cocoa and chocolate consumption, 33

2.9.1 Apparent cocoa consumption, 33

2.9.2 World chocolate consumption, 34

2.9.3 World consumption of chocolate products, 35

2.9.4 World consumption of premium chocolate products, 38

2.10 Fairtrade cocoa and chocolate in the modern confectionery industry, 39

2.10.1 Sustainable fairtrade cocoa production, 39

2.10.2 Future of the fairtrade cocoa and confectionery industry, 41

2.11 The organic cocoa in chocolate confectionery industry, 42

2.11.1 The global organic food industry, 42

2.11.2 The organic cocoa industry, 43

2.11.3 Consumption patterns of organic cocoa, 44

2.11.4 Certification and market for organic cocoa, 45

2.12 The changing chocolate market, 48

3 Traditional and modern cocoa cultivation practices, 49

3.1 Introduction, 49

3.2 Environmental requirements for cocoa cultivation, 51

3.2.1 Temperature, 51

3.2.2 Rainfall, 52

3.2.3 Soils and nutrition, 52

3.3 Traditional cocoa cultivation practices, 53

3.3.1 Growth and propagation, 53

3.4 Modern cocoa cultivation practices using vegetative propagation, 54

3.5 Establishment and shade, 54

3.6 Flowering and pod development, 60

3.7 Harvesting of cocoa pods, 64

3.8 Pod breaking, 67

3.9 The cocoa pod, 68

3.10 Good agricultural practices in cocoa cultivation, 69

3.10.1 Quality improvement practices, 69

3.10.2 Weed control, 71

3.10.3 Pruning, 71

4 Cocoa diseases and pests and their effects on chocolate quality, 73

4.1 Introduction, 73

4.2 Major cocoa diseases, 73

4.2.1 Cocoa swollen shoot virus disease (CSSVD), 73

4.2.2 Black pod disease, 74

4.2.3 Witches broom disease, 76

4.3 Cocoa pests, 77

4.3.1 Pod borers (capsids, cocoa thrips and mealy bugs), 77

4.4 Cocoa crop protection, 79

5 Cocoa bean composition and chocolate flavour development, 80

5.1 Introduction, 80

5.2 Bean composition and flavour precursor formation, 81

5.2.1 Physical structure and chemical composition of the cocoa bean, 81

5.2.2 Cocoa pulp: the fermentation substrate, 83

5.2.3 Polyphenols and chocolate flavour quality, 85

5.2.4 Effects of proteins and sugars on flavour precursor formation, 85

5.3 Effects of genotype on cocoa bean flavour, 87

5.4 Flavour development during post-harvest treatments of cocoa, 87

5.4.1 Changes in biochemistry of the bean during flavour precursor formation in cocoa fermentation, 87

5.4.2 Microbial succession and enzymatic activities during flavour precursor generation in cocoa fermentation, 90

5.4.3 Drying, 94

5.5 Conclusion, 98

6 Cocoa processing technology, 102

6.1 Introduction, 102

6.2 Bean selection and quality criteria, 102

6.2.1 Free fatty acid, 103

6.3 Cocoa quality, grading and storage, 106

6.4 Selection of bean blends and chocolate flavour quality, 107

6.5 Steps in cocoa processing, 108

6.5.1 Cleaning, breaking and winnowing, 108

6.5.2 Sterilization, 109

6.5.3 Alkalization, 109

6.5.4 Roasting, 110

6.5.5 Nib grinding and liquor treatment, 111

6.5.6 Liquor pressing, 112

6.5.7 Cake grinding (kibbling), 112

6.5.8 Cocoa powder production, 112

6.5.9 Cocoa butter –chemistry, standards and quality characteristics, 112

7 Industrial chocolate manufacture – processes and factors influencing quality, 117

7.1 Introduction, 117

7.2 Chocolate manufacturing processes, 120

7.2.1 Mixing, 120

7.2.2 Refining, 121

7.2.3 Conching, 123

7.3 Tempering, lipid crystallization and continuous phase character during chocolate manufacture, 126

7.4 Casting and moulding, 130

7.5 Cooling, 130

7.6 Demoulding, 130

7.7 Wrapping/Packaging, 132

7.8 Factors influencing rheological and textural qualities in chocolate, 132

7.8.1 Particle size distribution, 132

7.8.2 The role of fats, 142

7.8.3 The role of sugar, 143

7.8.4 The role of milk and other dairy components, 144

7.8.5 The role of surfactants, 145

7.8.6 Moisture and chocolate flow behaviour, 146

7.9 Chocolate quality and defects, 146

7.9.1 Chocolate quality, 146

7.9.2 Chocolate defects, 150

7.10 Conclusion and further research, 152

8 The chemistry of flavour development during cocoa processing and chocolate manufacture, 154

8.1 Introduction, 154

8.2 Influence of bean selection on chocolate flavour quality, 154

8.3 Effect of roasting, 155

8.3.1 Maillard reactions – aldol condensation, polymerization and cyclization, 159

8.3.2 Effects of alkalization, 161

8.4 Flavour development during chocolate manufacture, 162

8.4.1 Conching, 162

8.5 Key flavour compounds in milk chocolate, 163

8.6 Key flavour compounds in dark chocolate, 163

8.7 Conclusion, 169

9 Alternative sweetening and bulking solutions in chocolate manufacture, 171

9.1 Introduction, 171

9.2 Types of sugar substitutes and their characteristics, 172

9.3 High-potency sweeteners, 173

9.3.1 Stevia rebaudioside A, 173

9.3.2 Thaumatin, 176

9.4 Bulk sweeteners, 178

9.4.1 Polyols (sugar alcohols), 178

9.4.2 Sucralose, 181

9.4.3 Tagatose, 183

9.4.4 Trehalose, 185

9.4.5 Isomultulose, 187

9.5 Low-digestible carbohydrate polymers, 188

9.5.1 Polydextrose, 189

9.5.2 Inulin and oligofructose, 191

9.5.3 Maltodextrin, 193

9.6 Laxation and low–digestible carbohydrate polymers, 193

9.7 Applicability and suitability of different sweeteners and carbohydrate polymers in chocolate processing, 194

9.8 Importance of blending different sugar substitutes, 200

10 Sensory character and flavour perception of chocolates, 202

10.1 Summary and industrial relevance, 202

10.2 Introduction, 203

10.3 Sensory perception of quality in chocolates, 204

10.3.1 Appearance, 208

10.3.2 Texture, 208

10.3.3 Taste, 209

10.3.4 Flavour and aroma, 210

10.4 Sensory assessment of chocolates, 211

10.5 Factor influencing chocolate flavour, 212

10.6 Flavour release and perception of sweetness in chocolate, 213

10.7 Dynamism of flavour perception in chocolate, 215

10.8 Retronasal flavour release and perception during chocolate consumption, 216

10.9 Measurement of flavour release and intensity in chocolates, 218

10.10 Electronic noses and tongues as online sensors for sensory assessment of chocolates, 221

10.11 Conclusion, 222

11 Nutritional and health benefits of cocoa and chocolate consumption, 223

11.1 Summary and significance, 223

11.2 Introduction, 223

11.3 Chemistry and composition of cocoa flavonoids, 225

11.4 Chocolate types and their major nutritional constituents, 226

11.5 Antioxidant properties and their mechanism of action, 229

11.6 Effects on endothelial function, blood pressure and the cardiovascular system, 231

11.7 Effects on insulin sensitivity and carcinogenic properties, 232

11.8 Cocoa, chocolate and aphrodisiac properties, 233

11.9 Conclusion, 234

12 Processing effects on the rheological, textural and melting properties during chocolate manufacture, 236

12.1 Summary and industrial relevance, 236

12.2 Introduction, 237

12.3 Materials and methods, 241

12.3.1 Materials, 241

12.3.2 Preparation of chocolate samples, 241

12.3.3 Determination of particle size distribution, 242

12.3.4 Rheological measurements, 242

12.3.5 Tempering procedure, 244

12.3.6 Texture measurements, 244

12.3.7 Colour measurements of solid dark chocolate, 246

12.3.8 Microstructure analysis, 247

12.3.9 Determination of melting properties of dark chocolates, 248

12.3.10 Experimental design and statistical analysis, 248

12.4 Results and discussion, 249

12.4.1 Particle size distribution of molten dark chocolate, 249

12.4.2 Rheological properties of molten dark chocolate, 249

12.5 Relationships between Casson model and ICA recommendations, 258

12.6 Textural properties, 262

12.6.1 Molten dark chocolate, 262

12.6.2 Hardness of tempered dark chocolate, 266

12.6.3 Colour measurements, 267

12.6.4 Relationships between textural properties and appearance of dark chocolate, 268

12.7 Microstructural properties of molten dark chocolate, 270

12.8 Melting properties of dark chocolate, 274

12.8.1 Effects of particle size distribution, 276

12.8.2 Effects of fat content, 281

12.8.3 Effects of lecithin, 282

12.9 Relationships between rheological, textural and melting properties of dark chocolate, 284

12.10 Conclusion, 294

13 Tempering behaviour during chocolate manufacture: Effects of varying product matrices, 297

13.1 Summary and industrial relevance, 297

13.2 Introduction, 298

13.3 Materials and methods, 300

13.3.1 Materials, 300

13.3.2 Tempering procedure, 300

13.3.3 Determination of particle size distribution, 301

13.3.4 Experimental design and statistical analysis, 301

13.4 Results and discussion, 304

13.4.1 Particle size distribution of dark chocolates, 304

13.4.2 Effect of particle size distribution on tempering behaviour, 308

13.4.3 Effect of fat content on tempering behaviour, 312

13.5 Conclusion, 316

14 Tempering and fat crystallization effects on chocolate quality, 317

14.1 Summary and industrial relevance, 317

14.2 Introduction, 318

14.3 Materials and methods, 319

14.3.1 Materials, 319

14.3.2 Determination of particle size distribution, 320

14.3.3 Tempering experiment, 320

14.3.4 Texture measurements, 320

14.3.5 Colour and gloss measurements, 321

14.3.6 Image acquisition and capture, 321

14.3.7 Determination of melting properties, 322

14.3.8 Microstructural determinations, 322

14.3.9 Scanning electron microscopy, 322

14.3.10 Experimental design and statistical analysis, 323

14.4 Results and discussion, 323

14.4.1 Particle size distribution of dark chocolates, 323

14.4.2 Fat crystallization behaviours during tempering of dark chocolate, 324

14.4.3 Effect of temper regime and PSD on mechanical properties, 325

14.4.4 Effect of temper regime and PSD on colour and gloss, 328

14.4.5 Effect of temper regime and PSD on melting properties, 330

14.4.6 Effect of temper regime on microstructure, 339

14.4.7 Effect of temper regime on scanning electron microstructure, 339

14.5 Conclusion, 343

15 Fat bloom formation and development in chocolates, 345

15.1 Summary and industrial relevance, 345

15.2 Introduction, 346

15.3 Materials and methods, 347

15.3.1 Materials, 347

15.3.2 Determination of particle size distribution, 348

15.3.3 Tempering experiment, 348

15.3.4 Texture measurements, 349

15.3.5 Surface colour and gloss measurements, 349

15.3.6 Determination of melting properties, 349

15.3.7 Microstructural determinations, 350

15.3.8 Experimental design and statistical analysis, 350

15.4 Results and discussion, 350

15.4.1 Particle size distribution of dark chocolates, 350

15.4.2 Changes in textural properties during blooming, 351

15.4.3 Changes in appearance (Surface Whiteness and Gloss) during blooming, 353

15.4.4 Changes in melting behaviour during blooming, 357

15.4.5 Changes in microstructure during blooming, 359

15.5 Conclusion, 364

16 Matrix effects on flavour volatiles character and release in chocolates, 365

16.1 Summary and industrial relevance, 365

16.2 Introduction, 365

16.3 Materials and methods, 367

16.3.1 Materials, 367

16.3.2 Tempering procedure, 368

16.3.3 Determination of particle size distribution, 368

16.3.4 Quantification of flavour volatiles by gas chromatography, 368

16.3.5 Gas chromatography–olfactometry analytical conditions, 369

16.3.6 Experimental design and statistical analysis, 369

16.4 Results and discussion, 369

16.4.1 Particle size distribution of dark chocolates, 369

16.4.2 Characterization of flavour compounds in dark chocolates, 370

16.4.3 Effects of particle size distribution on flavour volatile release, 374

16.4.4 Effects of fat content on flavour volatile release, 374

16.4.5 Relating flavour volatiles release to particle size distribution and fat content: product spaces, 379

16.5 Conclusion, 381

17 Process optimization and product quality characteristics during sugar-free chocolate manufacture, 382

17.1 Summary and industrial relevance, 382

17.2 Introduction, 382

17.3 Materials and methods, 384

17.3.1 Raw materials, 384

17.3.2 Experimental design and sample preparation, 384

17.3.3 Analytical methods, 385

17.4 Results and discussion, 387

17.4.1 Rheological properties, 390

17.4.2 Casson plastic viscosity, 390

17.4.3 Casson yield stress, 392

17.4.4 Microscopy, 393

17.4.5 Colour, 395

17.4.6 Hardness, 395

17.4.7 Moisture, 396

17.5 Optimization of chocolate formulation, 396

17.6 Conclusion, 397

18 Food safety management systems in chocolate processing, 399

18.1 Introduction, 399

18.2 The HACCP system, 400

18.2.1 HACCP principles, 401

18.2.2 HACCP plan, 402

18.2.3 Application of the HACCP system, 405

18.2.4 Advantages of HACCP, 405

18.2.5 Shortfalls of HACCP, 406

18.3 ISO 22000 approach, 406

18.3.1 Advantages of ISO 22000, 407

18.3.2 Comparison of ISO 22000 with HACCP, 408

18.4 Hazards associated with chocolate processing, 408

18.4.1 Physical hazards, 408

18.4.2 Chemical hazards, 409

18.4.3 Microbiological hazards, 411

18.5 Critical operations in cocoa processing and chocolate manufacture, 413

18.5.1 Cleaning, 413

18.5.2 Roasting, 413

18.5.3 Breaking and winnowing, 414

18.5.4 Refining, 414

18.5.5 Conching, 414

18.5.6 Tempering, 415

18.6 Conclusion, 415

19 Application of ISO 22000 and hazard analysis and critical control points (HACCP) in chocolate processing, 416

19.1 Summary and industrial relevance, 416

19.2 Introduction, 416

19.2.1 Hazard analysis and critical control points (HACCP), 417

19.2.2 HACCP principles, 418

19.2.3 ISO 22000, 419

19.3 Hazards associated with chocolate processing, 419

19.3.1 Physical hazards, 420

19.3.2 Chemical hazards, 421

19.3.3 Microbiological hazards, 421

19.4 Preprocessing operations, 421

19.5 Cocoa processing into semi-finished products, 422

19.5.1 Bean receipt and cleaning – CCP1, 422

19.5.2 Silos (Storage) – CCP2, 422

19.5.3 De-bacterizer – CCP3, 422

19.5.4 The roasting process – CCP4, 422

19.5.5 Breaking and winnowing, 424

19.5.6 Milling, 424

19.5.7 Storage and conditioning – CCP5, 424

19.5.8 Pressing – CCP6, 425

19.5.9 Centrifugation and filtration – CCP7, 425

19.5.10 Kibbling and pulverization, 425

19.6 Milk chocolate manufacturing operations, 425

19.6.1 Raw materials reception – CCP1, 425

19.6.2 Mixing – CCP2, 425

19.6.3 Refining, 426

19.6.4 Conching, 427

19.6.5 Tempering, 427

19.6.6 Casting and moulding – CCP3, 428

19.6.7 Cooling, 428

19.6.8 Demoulding, 428

19.6.9 Wrapping/Packaging – CCP4, 429

19.7 Hazard analysis, 429

19.7.1 Determination of critical control points, 435

19.7.2 Determination of prerequisite programmes, 435

19.8 Conclusion, 435

20 Conclusions and industrial applications, 441

20.1 Introduction, 441

20.2 Conclusions: Structure–properties relationships in chocolate manufacture, 441

20.3 Conclusions: Tempering behaviour from response surface methodology, 443

20.4 Conclusions: Effects of tempering and fat crystallization on microstructure and physical properties, 444

20.5 Conclusions: Fat bloom formation and development with under-tempering, 445

20.6 Conclusions: Flavour volatiles and matrix effects related to variations in PSD and fat content, 445

20.7 Conclusions: Process optimization and product quality characteristics of sugar-free chocolates, 446

20.8 Industrial relevance and applications of research findings in this book, 447

20.9 Recommendations for further research studies, 448

References, 450

Appendix 1 Abbreviations, 487

Appendix 2 Acronyms and websites of organizations related to the cocoa and chocolate industry, 490

Appendix 3 Glossary of cocoa and chocolate terminologies, 492

Index, 497