Starch in Food (eBook)

Structure, Function and Applications

A-C Eliasson (Herausgeber)

eBook Download: PDF | EPUB

2004 | 1. Auflage
624 Seiten
Elsevier Reference Monographs (Verlag)
978-1-85573-909-3 (ISBN)

Infos

Starch is both a major component of plant foods and an important ingredient for the food industry. Starch in food reviews starch structure and functionality and the growing range of starch ingredients used to improve the nutritional and sensory quality of food.Part one illustrates how plant starch can be analysed and modified, with chapters on plant starch synthesis, starch bioengineering and starch-acting enzymes. Part two examines the sources of starch, from wheat and potato to rice, corn and tropical supplies. The third part of the book looks at starch as an ingredient and how it is used in the food industry. There are chapters on modified starches and the stability of frozen foods, starch-lipid interactions and starch-based microencapsulation. Part four covers starch as a functional food, investigating the impact of starch on physical and mental performance, detecting nutritional starch fractions and analysing starch digestion.Starch in food is a standard reference book for those working in the food industry. - Reviews starch structure and functionality - Extensive coverage of the growing range of starch ingredients - Examines how starch ingredients are used to improve the nutritional and sensory quality of food

Inhalt

Front Cover 1
Starch in Food: Structure, Function and Applications 4
Copyright Page 5
Table of Contents 6
Contributor contact details 14
Part I: Analysing and modifying starch 18
Chapter 1. Plant starch synthesis 20
1.1 Introduction: localization and function of starch in plants 20
1.2 Starch synthesis: enzyme reactions in plants and algae and glycogen synthesis in cyanobacteria 22
1.3 Properties of plant glucan synthesizing enzymes: ADP-glucose pyrophosphorylase 23
1.4 Properties of plant glucan synthesizing enzymes: starch synthase 35
1.5 Properties of plant glucan synthesizing enzymes: branching enzymes 42
1.6 Initiation of starch synthesis using a glucosyl-protein 50
1.7 Locating starch synthesis in plants: the plastid 50
1.8 In vivo synthesis of amylopectin 54
1.9 Regulating starch synthesis in plants 58
1.10 References 66
Chapter 2. Analysing starch structure 74
2.1 Introduction: characterising structures of starch components 74
2.2 Fractionation of starch 76
2.3 Analysis of amylose 77
2.4 Analysis of amylopectin structure 81
2.5 Analysis of intermediate materials 92
2.6 Analysis of chemically modified starches 94
2.7 Future trends 96
2.8 Sources of further information and advice 98
2.9 References 98
Chapter 3. Starch bioengineering 114
3.1 Introduction: the importance of starch 114
3.2 Technologies for genetic modification and starch profiling 116
3.3 Improving starch yield and structure 119
3.4 Physical and chemical properties of modified starches 128
3.5 Functionality and uses of modified starches in food processing 129
3.6 Ensuring successful modification of starch 131
3.7 Future trends 134
3.8 References 136
Chapter 4. Starch-acting enzymes 145
4.1 Introduction: the importance of enzymes 145
4.2 Using enzymes to modify starch 148
4.3 Developing starch-modifying enzymes for food processing applications 158
4.4 Future trends 165
4.5 References 166
Chapter 5. Understanding starch structure and functionality 173
5.1 Introduction: overview of packing at different lengthscales 173
5.2 The effect of amylopectin chain architecture on packing 178
5.3 Improving packing within starch granules 182
5.4 The gelatinisation process 186
5.5 Food processing: implications of starch granule structure 191
5.6 Conclusions and future trends 194
5.7 Sources of further information and advice 195
5.8 References 195
Chapter 6. Measuring starch in food 202
6.1 Introduction 202
6.2 Sample preparation 203
6.3 Methods of analysing starch in food 205
6.4 Determining starch in food: recent technological developments 215
6.5 Future trends 218
6.6 Sources of further information and advice 220
6.7 References 221
Part II: Sources of starch 226
Chapter 7. The functionality of wheat starch 228
7.1 Introduction: manufacture of wheat starch for the food industry 228
7.2 Granular and molecular structure of wheat starch 230
7.3 Functionality of wheat starch: granules, films and pastes 235
7.4 Rheological properties of starch pastes and gels 238
7.5 Improving and chemically modifying wheat starch for use in the food industry 242
7.6 Wheat starch syrups 248
7.7 Analysing starch-based products 251
7.8 Future trends 253
7.9 Sources of further information and advice 253
7.10 References 255
Chapter 8. Developments in potato starches 258
8.1 Introduction 258
8.2 Components and rheological properties of potato starch 259
8.3 Techniques for producing potato starch 262
8.4 Improving the functionality of potato starch for use in the food industry 263
8.5 Future trends 269
8.6 References 271
Chapter 9. The functionality of rice starch 275
9.1 Introduction 275
9.2 Rice flour and starch as food ingredient 277
9.3 Constituents of rice starch 278
9.4 Structure and functionality of rice starch 279
9.5 Gelatinization and the structure of rice starch 288
9.6 Retrogradation and other properties of rice starch 296
9.7 Improving rice starch functionality for food processing applications 300
9.8 Future trends 304
9.9 Sources of further information and advice 305
9.10 References 306
Chapter 10. New corn starches 312
10.1 Introduction: the use of corn starch in food processing 312
10.2 Improving the functionality of corn starch for food processing applications: natural corn endosperm mutants 315
10.3 Chemically modifying corn starches for use in the food industry 322
10.4 Genetically modifying corn starches for use in the food industry 328
10.5 Future trends 331
10.6 Sources of further information and advice 331
10.7 References 331
Chapter 11. Tropical sources of starch 338
11.1 Introduction: tropical sources of starch 338
11.2 Characteristics and properties of cassava starch 343
11.3 Characteristics and properties of sweet potato starch 351
11.4 Characteristics and properties of yam and aroid starches 353
11.5 Characteristics and properties of other minor root starches 358
11.6 Modifying `tropical' starches for use in the food industry 367
11.7 Future trends 370
11.8 References 370
Part III: Applications 378
Chapter 12. Starch as an ingredient: manufacture and applications 380
12.1 Introduction 380
12.2 Manufacture 380
12.3 Structure 385
12.4 Modifications 387
12.5 Technical data 391
12.6 Uses and applications 396
12.7 Regulatory status: European label declarations 407
12.8 Acknowledgements 409
12.9 Bibliography 409
Chapter 13. Utilizing starches in product development 410
13.1 Introduction 410
13.2 Components of starch 411
13.3 Food applications for natural and modified starches 413
13.4 Methods of starch selection 416
13.5 Factors affecting starch in food products 419
13.6 Using the functional properties of starch to enhance food products 426
13.7 References 440
Chapter 14. Modified starches and the stability of frozen foods 442
14.1 Introduction 442
14.2 The structure and stability of frozen foods 443
14.3 The role of modified starch in stabilizing frozen foods 449
14.4 Future trends 453
14.5 Sources of further information and advice 453
14.6 References 454
Chapter 15. Starch-lipid interactions and their relevance in food products 458
15.1 Introduction 458
15.2 The structure and properties of the starch-lipid complex 458
15.3 Analysis of starch: lipids and emulsifiers 465
15.4 The effect of lipids on starch behaviour 467
15.5 Enzymatic degradation of amylose-lipid complexes 470
15.6 Future trends 471
15.7 References 471
Chapter 16. Starch-based microencapsulation 478
16.1 Introduction: using microencapsulation in food processing 478
16.2 Using starch in microencapsulation: starch hydrolysates, derivatives, polymers and granules 481
16.3 Starch-based shell matrices for food ingredients 486
16.4 Future trends 487
16.5 References 488
Part IV: Starch and health 492
Chapter 17. Development of a range of industrialised cereal-based foodstuffs high in slowly digestible starch 494
17.1 Introduction 494
17.2 Characteristics and properties of starch and starchy foods 498
17.3 Low GI diets and their associated health benefits 505
17.4 Case study: low glycaemic index, high slowly digestible starch plain biscuits, the EDP­® (`Long-lasting energy') range developed by Danone, Vitapole 511
17.5 Future trends 515
17.6 Sources of further information and advice 515
17.7 Acknowledgements 516
17.8 References 517
Chapter 18. Starch: physical and mental performance 522
18.1 Introduction 522
18.2 Physical performance: energy requirements, delivery and availability 524
18.3 Mental performance: the effects of glucose 535
18.4 Mental performance: the effects of CHO and glucose during the day 540
18.5 Future trends 548
18.6 References 549
Chapter 19. Detecting nutritional starch fractions 558
19.1 Introduction 558
19.2 Methods of determining RAG, SAG and RS fractions 561
19.3 Quality control and troubleshooting 568
19.4 Carbohydrate bioavailability data for selected foods 570
19.5 Conclusion and future trends 570
19.6 Acknowledgement 574
19.7 References 574
Chapter 20. Resistant starch 577
20.1 Introduction 577
20.2 Effects of resistant starch on the digestive system 579
20.3 Improving the functional effects of resistant starch 584
20.4 Future trends 588
20.5 Sources of further information and advice 588
20.6 References 589
Chapter 21. Analysing starch digestion 592
21.1 Introduction 592
21.2 Starch and the prevention of hypo- and hyperglycemia 592
21.3 The determinants of the rate of absorption of starch-derived glucose 595
21.4 Techniques for monitoring starch digestion 598
21.5 Current applications of slowly available starch and the prevention of hyper- and hypoglycemia 600
21.6 Future trends 603
21.7 Sources of further information and advice 604
21.8 References 604
Index 607

Textauszug

1

Plant starch synthesis

J. Preiss    Michigan State University, USA

1.1 Introduction: localization and function of starch in plants

This chapter reviews starch synthesis in higher plants and algae. Since the reactions leading to glycogen synthesis in the cyanobacteria are similar to those observed in the higher plants there will be some referral to studies in those organisms particularly in regulation of cyanobacterial α1,4-glucan synthesis. The enzymology and biochemistry of the various enzymes in the plant, algal and cyanobacterial systems will also be described. In view of the existing information available on the properties of the starch biosynthetic enzymes and the effects of certain mutants on starch structure a pathway of starch synthesis is described which postulates specific functions for the starch synthases and branching enzymes. Finally regulation of starch synthesis at the enzymatic level will be discussed and in relation to this regulation, recent results indicating how starch content has been increased in certain plants will be descibed. A previous chapter1 in the second edition of Starch Chemistry and Technology which reviewed starch biosynthesis discussed the various maize endosperm mutants or mutant combinations, 26 of them, that showed an effect on the quantity or the nature of the starch formed. This information remains of interest and the reader is referred to that review. However, for many of those mutants the biochemical basis for mutation effects on starch quantity or quality was unknown. This review will deal with only the mutants where the biochemical process affected by the mutation has been elucidated to at least some extent. There are some recent reviews on starch biosynthesis2-11 that discuss many of the areas presented in this chapter.

1.1.1 Leaf starch

Starch is deposited in granules in almost all green plants and in various types of plant tissues and organs, e.g., leaves, roots, shoots, fruits, grains, and stems. Illumination of the leaf in bright light causes the formation of starch granules in the chloroplast organelle and was demonstrated in the nineteenth century.12 Disappearance of the starch occurs either by exposure of the leaf to low light or by extended exposure in the dark (24-48 hours). This is readily observed by iodine staining of the tissue13 or by light or electron microscopy.14 Starch accumulates due to carbon fixation during photosynthesis and the starch formed in the light is degraded in the dark to products that are in most cases utilized for sucrose synthesis. Mutants of Arabidopsis thaliana unable to synthesize starch, grow at the same rate as the wild type in a continuous light regime because they are able to synthesize sucrose,15 but their growth rate is drastically reduced if grown in a day-night regime. The reason for this is that the accumulated starch is required for sucrose synthesis at night; the sucrose is transported from the leaf to the sink tissues. Biosynthesis and degradation of starch in the leaf is therefore a dynamic process having diurnal fluctuations in its stored levels.

Starch also plays an important role in the operation of stomatal guard cells, where it is degraded during the day. In the late afternoon or evening while the stomata are open, the starch is resynthesized. Leaf starch is lower in amylose content than what is observed in storage tissues.16 The amylose structure is also of a smaller molecular size.

1.1.2 Starch in storage tissues

In storage organs, fruit or seed, during the development and maturation of the tissue, synthesis of starch occurs. At the time of sprouting or germination of the seed or tuber, or ripening of the fruit, starch degradation in these tissues then occurs and the derived metabolites are used as a source both for carbon and energy. The degradative and biosynthetic processes in the storage tissues may therefore be temporally separated. However, there is some possibility that during each phase of starch metabolism some turnover of the starch molecule occurs.

The main site of starch synthesis and accumulation in the cereals is the endosperm, with starch granules that are located within the amyloplasts. Starch content in potato tuber, maize endosperm, and in roots of yam, cassava and sweet potato ranges between 65 and 90% of the total dry matter. Patterns of starch accumulation during development of the tissue are specific to the species and are related to the unique pattern of differentiation of the organ.

Starch granules in storage tissues can vary in shape, size and composition. The shape and size of the granules depends on the source, but in each tissue there is a range of sizes and shapes. The diameter of the starch granule changes during the development of the reserve tissue. There are also some fine features, characteristic of each species, e.g., the ‘growth rings’, spaced 4–7 μm apart, and the fibrillar organization seen in potato starch, which allows one to identify the botanical source of the starch by microscopic examination.

Two polymers are distinguished in the starch granule. Amylose, which is essentially linear, and amylopectin, highly branched. Amylose is mainly found as linear chains of about 840 to 22,000 units of α-D-glucopyranosyl residues linked by α-(1- > 4) bonds (molecular weight around 136,000 to 3.5 × 106). The number of anhydroglucose units, however, varies quite widely with plant species and stage of development. Some of the amylose molecules are branched to a small extent (α-l- > 6-D glucopyranose; one per 170 to 500 glucosyl units). Amylopectin, in contrast, which usually comprises about 70% of the starch granule, is more highly branched with about 4 to 5% of the glucosidic linkages being α-1- > 6.

Amylopectin molecules are large flattened disks consisting of α-(1,4)-glucan chains joined by frequent α-(1,6)-branch points. Many models of amylopectin structure have been proposed but from these the most satisfactory models, i.e., those that best fit the experimental data available, are those proposed by Robin et al.17, Manners and Matheson18 and by Hizukuri.19 These are known as cluster models. The chemical and physical aspects of the starch granule and its components amylose and amylopectin have been discussed in some recent excellent reviews by Morrison and Karkalis20 and Hizukuri.21

1.2 Starch synthesis: enzyme reactions in plants and algae and glycogen synthesis in cyanobacteria

1.2.1 Enzyme reactions of starch synthesis

The sugar nucleotide utilized for synthesis of the α-1,4 glucosidic linkages in amylose and amylopectin is ADP-glucose and not UDP-glucose. ADP-glucose synthesis is catalyzed by ADP-glucose (synthetase) pyrophosphorylase (reaction 1, E.C. 2.7.7.27; ATP:α-D-glucose-l-phosphate adenylyltransferase).

TP+α‐glucose‐1‐P⇔ADP‐glucose+PPi

  1.1

DP‐glucose+α‐1,4glucan⇒α−1,4−glucosyl‐α‐1,4glucan+ADP

  1.2

α‐1,4‐oligosaccharidechain⇒α‐1,4‐α‐1,6branched‐glucanpro‐amylopectinphytoglyvogen

  1.3

Reaction 2 is catalyzed by starch synthase (E.C. 2.4.1.21; ADP-glucose;1,4-α-D-glucan 4-α-glucosyltransferase). A similar reaction is noted for glycogen synthesis in cyanobacteria and other bacteria (see references 22 and 23 but the reaction is referred to as glycogen synthase (also E.C. 2.4.1.21). Reaction 3 is catalyzed by branching enzyme (E.C. 2.4.1.18; 1,4-α-D-glucan 6-α-(l,4-α-glucano)-transferase). The branch chains in amylopectin are longer (about 20 to 24 glucose units long) and there is less branching in amylopectin (~ 5% of the glucosidic linkages are α-1,6 as seen in glycogen (10-13 glucose units long and 10% of linkages are α-1,6). Thus, the starch branching enzymes may have different properties with respect to size of chain transferred, or placement of branch point, than enzyme that branches glycogen. Alternatively, the interaction of the starch branching enzymes with the starch synthases may be different from the interaction of the bacterial branching enzymes with their respective glycogen synthases. The chain elongating properties of the starch synthases could be different from those observed for the bacterial glycogen synthases and may account for some of the differences observed in the amylopectin structure. The differences in the catalytic properties of the starch synthases and branching enzymes isolated from different plant sources may also account for the differences observed in the various plant starch structures.

Isozymic forms of plant starch synthases (cited in references, 3, 4, 24-28) and branching enzymes (cited in references 3, 4, 24, and in recent literature, 29-34) have been reported. They seem to play different roles in the synthesis of the two polymers of starch, amylose and amylopectin and are products from different genes. In many...

Produkt-Details

• Erscheint lt. Verlag: 1.8.2004
• Sprache: englisch
• Themenwelt: Technik ► Lebensmitteltechnologie
• ISBN-10: 1-85573-909-7 / 1855739097
• ISBN-13: 978-1-85573-909-3 / 9781855739093