Bread Making (eBook)
608 Seiten
Elsevier Science (Verlag)
978-1-85573-712-9 (ISBN)
There has been a wealth of recent research on the complex changes involved in bread making and how they influence the many traits consumers use to define quality. Bread making: improving quality sums up this key research and what it means for improved process control and a better, more consistent product.After an introductory review of bread making as a whole part one discusses wheat and flour quality. Chapter 3 summarises current research on the structure of wheat, providing the context for chapters on wheat proteins (chapters 5 and 6) and starch (chapter 7). There are also chapters on ways of measuring wheat and flour quality, and improving flour for bread making. Part two reviews dough formation and its impact on the structure and properties of bread. It includes chapters on the molecular structure of dough, foam formation and bread aeration together with discussion of the role of key ingredients such as water. A final group of chapters then discusses other aspects of quality such as improving taste and nutritional properties, as well as preventing moulds and mycotoxin contamination.With its distinguished editor and international team of contributors, Bread making: improving quality is a standard work both for industry and the research community.
Front Cover 1
Bread Making: Improving Quality 4
Copyright Page
5
Table of Contents 6
Contributor contact details 14
Chapter 1. Introduction 20
1.1 Wheat and its special properties 21
1.2 Converting wheat to flour 22
1.3 Making bread 23
1.4 Functional ingredients 24
1.5 Bread in the future 25
1.6 References 26
Chapter 2. Breadmaking: an overview 27
2.1 Introduction 27
2.2 Bread dough development 29
2.3 Breadmaking processes 30
2.4 What determines bread quality? 33
2.5 Dough mixing and processing 36
2.6 Cell creation during mixing 38
2.7 Dough processing 39
2.8 Gas bubble control during dough processing 42
2.9 Proving and baking 43
2.10 Future trends 45
2.11 Sources of further information and advice 46
2.12 References 46
Part I: Wheat and flour quality 48
Chapter 3. The chemistry and biochemistry of wheat 50
3.1 Introduction: the structure of the wheat kernel 50
3.2 Wheat carbohydrates 53
3.3 Wheat proteins 63
3.4 Wheat lipids 76
3.5 Wheat enzymes 79
3.6 Pigments 80
3.7 Future trends in wheat utilisation 80
3.8 Sources of further information and advice 84
3.9 References 85
Chapter 4. Assessing grain quality 90
4.1 Introduction: the interaction of genotype with the environment 90
4.2 The importance of variety 92
4.3 Environmental factors affecting grain quality 95
4.4 Storage and transport 98
4.5 Critical quality attributes and their analysis 99
4.6 Grain quality bargaining 110
4.7 Future trends 111
4.8 Sources of further information and advice 111
4.9 References 111
Chapter 5. Techniques for analysing wheat proteins 116
5.1 Introduction 116
5.2 Separation methods 117
5.3 Analysing molecular properties 118
5.4 Rheological measurements 120
5.5 Infrared spectroscopy 122
5.6 NMR spectroscopy 124
5.7 Electron spin resonance spectroscopy 130
5.8 Future trends 132
5.9 References 134
Chapter 6. Wheat proteins and bread quality 140
6.1 Introduction: cereal protein classification 140
6.2 Cereal proteins and breadmaking quality 147
6.3 Prolamin structure and bread quality 148
6.4 Soluble proteins, xylanase inhibitors and bread quality 152
6.5 Detergent-solubilised proteins and bread quality 154
6.6 Genomics and the wheat grain proteome 155
6.7 Conclusion and future trends 158
6.8 Acknowledgements 158
6.9 References 158
Chapter 7. Starch structure and bread quality 164
7.1 Introduction: the importance of starch structure to bread quality 164
7.2 Starch properties and baking performance 165
7.3 Starch structure 170
7.4 Starch structure and bread quality 175
7.5 Future trends 179
7.6 Sources of further information and advice 180
7.7 References 180
Chapter 8. Improving wheat quality: the role of biotechnology 187
8.1 Introduction 187
8.2 Wheat gluten proteins 187
8.3 HMW subunits and bread quality 190
8.4 The genetic transformation of wheat 194
8.5 Manipulating HMW subunit composition and dough properties 196
8.6 Future trends: improving bread quality 199
8.7 Sources of further information and advice 201
8.8 Acknowledgements 201
8.9 References 201
Chapter 9. Analysing wheat and flour 206
9.1 Introduction 206
9.2 Sample collection and preparation 208
9.3 Grain quality parameters 208
9.4 Flour quality: protein 210
9.5 Flour quality: starch and other attributes 214
9.6 Conclusion 216
9.7 Sources of further information and advice 216
9.8 References 217
Chapter 10. Milling and flour quality 219
10.1 Introduction 219
10.2 Flour milling 220
10.3 Flour milling and flour quality 229
10.4 Milling research 235
10.5 The future of flour milling 236
10.6 Conclusion 237
10.7 References 237
Chapter 11. Modifying flour to improve functionality 239
11.1 Introduction 239
11.2 Definition of some key terms and components 240
11.3 Protein modification and breadmaking quality 244
11.4 Genetic modification of flour properties 262
11.5 References 265
Chapter 12. The nutritional enhancement of wheat flour 272
12.1 Introduction 272
12.2 The nutritional value of wheat 274
12.3 Increasing the nutritional value of wheat flour 276
12.4 Improving the nutritional value of wholewheat flours 281
12.5 Future trends: protein supplementation and fibre enhancement 282
12.6 Sources of further information and advice 285
12.7 References 285
Part II: Dough and bread quality 290
Chapter 13. The molecular basis of dough rheology 292
13.1 Introduction 292
13.2 Factors affecting dough rheology 293
13.3 Polymer networks in doughs 296
13.4 The molecular mechanism of energy storage in dough 298
13.5 How much dough rheology can we explain? 302
13.6 Future trends 303
13.7 Sources of further information and advice 304
13.8 Acknowledgement 305
13.9 References 305
Chapter 14. Molecular mobility in dough and bread quality 307
14.1 Introduction 307
14.2 Molecular mobility in dough 308
14.3 Dough properties in baking 314
14.4 Controlling molecular mobility to improve bread quality 317
14.5 Future trends 320
14.6 Sources of further information and advice 321
14.7 References 321
Chapter 15. The role of water in dough formation and bread quality 325
15.1 Introduction 325
15.2 Dough as a disperse system 326
15.3 Water displacements in dough 328
15.4 Dough proofing and baking 331
15.5 Dough freezing 334
15.6 Future trends 336
15.7 Sources of further information and advice 336
15.8 References 337
Chapter 16. Foam formation in dough and bread quality 340
16.1 Introduction 340
16.2 Foam formation 341
16.3 Foam stability 343
16.4 Surface active dough components 347
16.5 The aqueous phase of dough and foam formation 349
16.6 Dough composition and foam stability 352
16.7 Processing stages and foam stability 358
16.8 Analytical techniques 359
16.9 Future trends 363
16.10 Sources of further information and advice 364
16.11 References 365
Chapter 17. Bread aeration 371
17.1 Introduction 371
17.2 The development of bread aeration studies 374
17.3 Aeration during breadmaking: mixing 376
17.4 Aeration during proving 380
17.5 Aeration during baking 383
17.8 Acknowledgements 388
17.9 Further reading 388
17.10 References 390
Chapter 18. Measuring the rheological properties of dough 394
18.1 Introduction: dough rheology and bread quality 394
18.2 The role of rheology in quality control 396
18.3 Rheological tests 397
18.4 Descriptive rheological measurements 399
18.5 Fundamental rheological tests 401
18.6 Baking quality and rheology 408
18.7 Future trends 414
18.8 References 414
Chapter 19. Controlling dough development 420
19.1 Introduction 420
19.2 Dough rheology during mixing 421
19.3 Dough development 423
19.4 The effects of mixer type 425
19.5 Controlling dough development 427
19.6 Emerging methods for controlling dough development 432
19.7 Future trends 438
19.8 Sources of further information and advice 438
19.9 References 440
Chapter 20. The use of redox agents 443
20.1 Introduction 443
20.2 The redox state in flour 444
20.3 Redox reactions during processing 450
20.4 Redox agents: oxidants and reductants 454
20.5 Future trends 461
20.6 Sources of further information and advice 462
20.7 References 462
Chapter 21. Water control in baking 466
21.1 Introduction: water composition and properties 466
21.2 Hygrometry and water hardness 469
21.3 The water absorption capacity of flour 471
21.4 Dough formation 472
21.5 Proving and baking 476
21.6 Water activity and the shelf-life of bread 481
21.7 Future trends 483
21.8 Sources of further information and advice 484
21.9 References 484
Chapter 22. Improving the taste of bread 486
22.1 Introduction 486
22.2 Elements of bread flavor 488
22.3 Ingredients and flavor: flour and water 490
22.4 Ingredients and flavor: yeast and lactic acid fermentation 493
22.5 Processing and flavor: mixing, fermentation and baking 495
22.6 Innovations in bread flavor 497
22.7 References 503
Chapter 23. High-fibre baking 506
23.1 Introduction 506
23.2 Sources of fibre in baking 507
23.3 Problems in high-fibre baking 509
23.4 Improving the quality of high-fibre bread 511
23.5 Future trends 515
23.6 References 516
Chapter 24. Mould prevention in bread 519
24.1 Introduction: the problem of mould in bread 519
24.2 Current techniques for mould control and their limitations 521
24.3 Developing new methods for mould control 524
24.4 Future trends 529
24.5 Sources of further information and advice 530
24.6 References 530
Chapter 25. Detecting mycotoxin contamination of cereals 534
25.1 Introduction: the problem of mycotoxin contamination 534
25.2 Mycotoxins in the food chain 535
25.3 Detecting mycotoxins 541
25.4 The regulatory context 546
25.5 Future trends 547
25.6 References 549
Chapter 26. Improving wheat quality 555
26.1 Introduction 555
26.2 US wheat classification and grading 556
26.3 Breeding and wheat quality 559
26.4 Quality indices and tests 562
26.5 Predicting the breadmaking quality of wheat 568
26.6 Future trends 573
26.7 References 576
Chapter 27. Preventing bread staling 581
27.1 Introduction 581
27.2 Economic significance of staling 581
27.3 The process of bread staling 582
27.4 Factors affecting bread staling 582
27.5 Techniques for preventing bread staling 587
27.6 Future trends 589
27.7 Sources of further information and advice 589
27.8 References 590
Index 594
Breadmaking: an overview
S. Cauvain Campden and Chorleywood Food Research Association, UK
2.1 Introduction
Bread is a staple foodstuff, which is made and eaten in most countries around the world. Bread products have evolved to take many forms, each based on quite different and distinctive characteristics. Over the centuries craft bakers have developed our traditional bread varieties using their accumulated knowledge as to how to make best use of their available raw materials to achieve the desired bread quality. In some countries the nature of breadmaking has retained its traditional form while in others it has changed dramatically. The proliferation of bread varieties derives from the unique properties of wheat proteins to form gluten and from the bakers’ ingenuity in manipulating the gluten structures formed within the dough. The rubbery mass of gluten with its ability to deform, stretch, recover shape and trap gases is very important in the production of bread and all fermented products. Of all the cereals, wheat is almost unique in this respect.
The term ‘bread’ is used to describe such a wide range of products with different shapes, sizes, textures, crusts, colours, softness, eating qualities and flavours that the terms ‘good’ or ‘bad’ quality tend to have no real meaning, except to the individual making the assessment. A baguette is not a baguette without a crisp crust, while the same crust formation would be unacceptable on north American pan bread and the fine cell structure of sandwich bread in the UK has no relevance to the flat breads of the Middle East.
The character of bread and other fermented products depends heavily on the formation of a gluten network which traps gas from yeast fermentation and makes a direct contribution to the formation of a cellular crumb structure which, after baking, confers texture and eating qualities quite different from other baked products. Look closely at the crumb structures of most baked breads and you will see that the common linking theme is that they are formed of holes of differing shapes, sizes and distributions. Each hole is embraced by a network of connected strands, coagulated gluten, in which starch granules and bran particles are firmly embedded. When this crumb is subjected to pressure with the fingers it deforms, and when the force is removed it springs back to assume its original shape, at least when the product is fresh. This combination of a cellular crumb with the ability to recover after being compressed largely distinguishes breads from other baked products: these are the very characteristics that bakers seek to achieve in most bread products.
While there are many different breadmaking processes, they have the common aim of converting wheat flour and other ingredients into a light, aerated and palatable food. The move to improve the digestibility of the wild grass seed forerunners of early wheat types through fermentation and baking represents a major step in the development of human food production. The unique properties of the proteins in wheat with their ability to form a cohesive mass of dough once the flour has been hydrated and subjected to the energy of mixing, even by hand, provides the basis of the transition from flour to bread. This cohesive mass is the one bakers call ‘gluten’ and once it has formed into a dough it has the ability to trap gases during fermentation, proof and baking which allows the mass to expand to become a softer, lighter and more palatable as a food after baking. The discovery that dough left for long periods of time would increase in volume without being subjected to the high temperatures of baking identified the basis of fermentation. The combined effect of these rheological changes is for the baked mass to increase in volume and give a product with an even softer, more digestible character and different flavour.
There are a few basic steps that form the basis of all breadmaking. They can be listed as follows:
• The mixing of wheat flour and water, together with yeast and salt, and other specified ingredients in appropriate ratios.
• The development of a gluten structure in the dough through the application of energy during mixing.
• The incorporation of air bubbles within the dough during mixing.
• The continued ‘development’ of the gluten structure created in order to modify the rheological properties of the dough and to improve its ability to expand when gas pressures increase during fermentation.
• The creation and modification of particular flavour compounds in the dough.
• Thesubdivision of the dough mass into unit pieces.
• A preliminary modification of the shape of the divided piece.
• A short delay in processing to further modify physical and rheological properties of the dough pieces.
• The shaping of the dough pieces to their required shape.
• The fermentation and expansion of the shaped dough pieces during proof.
• Further expansion of the dough pieces and fixation of the final bread structure during baking.
• Cooling and storage of the final product before consumption.
Loss of product freshness is as much about what we expect a product character to be as it is about its age since original manufacture. Whatever the criteria we use to judge bread staleness it becomes clear that the single most common requirement of fermented products is that it should ideally retain all of the attributes that it had when it left the oven; above all else we expect our bread to be ‘fresh’. When we collect our bread from the baker and it is still warm to the touch we have no doubt as to its freshness, but when we purchase it cold from the store shelf we need convincing as to its freshness.
Raw materials and the processes used change and are time and temperature sensitive. To be able to make our particular bread type we must have an understanding of the complex interactions between our raw materials and the methods we will use in the conversion processes from ingredients to baked product.
2.2 Bread dough development
Dough development is a relatively undefined term that covers a number of complex changes that begin when the ingredients first become mixed. These changes are associated with the formation of gluten, which requires both the hydration of the proteins in the flour and the application of energy through the process of kneading. The role of energy in the formation of gluten is not always fully appreciated but it is a significant contributor to the breadmaking process.
There is more to dough development than a simple kneading process. The process of developing bread dough brings about changes in the physical properties of the dough and in particular improvement in its ability to retain the carbon dioxide gas which will later be generated by yeast fermentation. This improvement in gas retention ability is particularly important when the dough pieces reach the oven. In the early stages of baking before the dough has set, yeast activity is at its greatest and large quantities of carbon dioxide gas are being generated and released from solution in the aqueous phase of the dough. If the dough pieces are to continue to expand at this time then the dough must be able to retain a large quantity of that gas being generated and it can do this only if we have created a gluten structure with the appropriate physical properties.
It is important to distinguish between gas production and gas retention in fermented dough. Gas production refers to the generation of carbon dioxide gas as a natural consequence of yeast fermentation. Provided the yeast cells in the dough remain viable and there is sufficient substrate, then gas production will continue, but expansion of the dough can occur only if that carbon dioxide gas is retained in the dough. Not all of the gas generated during the breadmaking process will be retained within the dough before it finally sets in the oven. The proportion that will be retained depends on the development of a suitable gluten matrix within which the expanding gas can be held. Gas retention in dough is therefore closely linked with the degree of dough development. The most commonly considered factors are those related to the protein component of wheat flour; however, dough development will be affected by a large number of ingredients and processing parameters, many of which are not necessarily independent of one another.
2.3 Breadmaking processes
The development of no-time (i.e. no resting time in bulk before dividing) dough-making processes changed traditional (pre-1960) breadmaking. Foremost in these changes was the invention of the Chorleywood Bread Process (CBP) in which the development of optimum dough qualities is achieved in the mixer by measuring a defined energy expenditure rather than through the effects of fermentation (Cauvain, 1998). The result of the introduction of the CBP was to eliminate the need for bulk fermentation periods with considerable raw material and time savings, as well as to initiate changes in ingredient and processing technologies. The principles of the CBP were adopted in many countries around the world (Gould,...
| Erscheint lt. Verlag | 31.8.2003 |
|---|---|
| Sprache | englisch |
| Themenwelt | Technik ► Lebensmitteltechnologie |
| ISBN-10 | 1-85573-712-4 / 1855737124 |
| ISBN-13 | 978-1-85573-712-9 / 9781855737129 |
| Informationen gemäß Produktsicherheitsverordnung (GPSR) | |
| Haben Sie eine Frage zum Produkt? |
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