Nanotechnology Research Methods for Food and Bioproducts

Food nanotechnology is an expanding field. This expansion is based on the advent of new technologies for nanostructure characterization, visualization, and construction. Nanotechnology Research Methods for Food and Bioproducts introduces the reader to a selection of the most widely used techniques in food and bioproducts nanotechnology. This book focuses on state-of-the-art equipment and contains a description of the essential tool kit of a nanotechnologist. Targeted at researchers and product development teams, this book serves as a quick reference and a guide in the selection of nanotechnology experimental research tools.

Foreword xi

Contributors xiii

1 Introduction 1
Graciela W. Padua

References 3

2 Material components for nanostructures 5
Graciela W. Padua and Panadda Nonthanum

2.1 Introduction 5

2.2 Self-assembly 6

2.3 Proteins and peptides 8

2.3.1 Amyloidogenic proteins 8

2.3.2 Collagen 9

2.3.3 Gelatin 9

2.3.4 Caseins 10

2.3.5 Wheat gluten 10

2.3.6 Zein 10

2.3.7 Eggshell membranes 10

2.3.8 Bovine serum albumin 11

2.3.9 Enzymes 11

2.4 Carbohydrates 11

2.4.1 Cyclodextrins 11

2.4.2 Cellulose whiskers 12

2.5 Protein–polysaccharides 13

2.6 Liquid crystals 14

2.7 Inorganic materials 14

References 15

3 Self-assembled nanostructures 19
Qin Wang and Boce Zhang

3.1 Introduction 19

3.2 Self-assembly 20

3.2.1 Introduction 20

3.2.2 Micelles 20

3.2.3 Fibers 21

3.2.4 Tubes 23

3.3 Layer-by-layer assembly 24

3.3.1 Introduction 24

3.3.2 Nanofilms on planar surfaces from LbL 25

3.3.3 Nanocoatings from LbL 27

3.3.4 Hollow nanocapsules from LbL 28

3.4 Nanoemulsions 29

3.4.1 Introduction 29

3.4.2 High-energy nanoemulsification methods 30

3.4.3 Low-energy nanoemulsification methods 31

3.4.4 Nanoparticles generated from different nanoemulsions and their applications 33

References 34

4 Nanocomposites 41
Graciela W. Padua, Panadda Nonthanum and Amit Arora

4.1 Introduction 41

4.2 Polymer nanocomposites 42

4.3 Nanocomposite formation 43

4.4 Structure characterization 44

4.5 Biobased nanocomposites 45

4.5.1 Starch nanocomposites 46

4.5.2 Pectin nanocomposites 46

4.5.3 Cellulose nanocomposites 47

4.5.4 Polylactic acid nanocomposites 47

4.5.5 Protein nanocomposites 48

4.6 Conclusion 50

References 50

5 Nanotechnology-enabled delivery systems for food functionalization and fortification 55
Rashmi Tiwari and Paul Takhistov

5.1 Introduction: functional foods 55

5.2 Food matrix and food micro-structure 56

5.3 Target compounds: nutraceuticals 58

5.3.1 Solubility and bioavailability of nutraceuticals 60

5.3.2 Interaction of nutraceuticals with food matrix 61

5.4 Delivery systems 64

5.4.1 Overcoming biological barriers 64

5.4.2 Nano-scale delivery systems 65

5.4.3 Types/design principles 67

5.4.4 Modes of action 69

5.5 Examples of nanoscale delivery systems for food functionalization 72

5.5.1 Liposomes 72

5.5.2 Nano-cochleates 74

5.5.3 Hydrogels-based nanoparticles 75

5.5.4 Micellar systems 75

5.5.5 Dendrimers 77

5.5.6 Polymeric nanoparticles 78

5.5.7 Nanoemulsions 80

5.5.8 Lipid nanoparticles 81

5.5.9 Nanocrystalline particles 83

5.6 Conclusions 85

References 85

6 Scanning electron microscopy 103
Yi Wang and Vania Petrova

6.1 Background 103

6.1.1 Introduction to the scanning electron microscope 103

6.1.2 Why electrons? 104

6.1.3 Electron–target interaction 104

6.1.4 Secondary electrons (SEs) 105

6.1.5 Backscattered electrons (BSEs) 106

6.1.6 Characteristic X-rays 107

6.1.7 Overview of the SEM 107

6.1.8 Electron sources 108

6.1.9 Lenses and apertures 109

6.1.10 Electron beam scanning 109

6.1.11 Lens aberrations 110

6.1.12 Vacuum 111

6.1.13 Conductive coatings 111

6.1.14 Environmental SEMs (ESEMs) 111

6.2 Applications 111

6.2.1 Zein microstructures 112

6.2.2 Controlled magnifications 115

6.2.3 Nanoparticles 117

6.3 Limitations 119

6.3.1 Radiation damage 120

6.3.2 Contamination 122

6.3.3 Charging 124

References 126

7 Transmission electron microscopy 127
Changhui Lei

7.1 Background 127

7.2 Instrumentations and applications 128

7.2.1 Interactions between incident beam and specimen 129

7.2.2 Conventional TEM 130

7.2.3 Scanning TEM 136

7.2.4 Analytical electron microscopy 139

7.3 Sample preparations 142

7.4 Limitations 143

References 143

8 Dynamic light scattering 145
Leilei Yin

8.1 The principle of dynamic light scattering 145

8.2 Photon correlation spectroscopy 151

8.3 DLS apparatus 152

8.4 DLS data analysis 156

8.4.1 Multiple-decay methods 158

8.4.2 Regularization methods 158

8.4.3 Maximum-entropy method 159

8.4.4 Cumulant method 159

References 160

9 X-ray diffraction 163
Yi Wang and Phillip H. Geil

9.1 Background 163

9.1.1 Introduction 163

9.1.2 Classical X-ray setup 165

9.1.3 X-ray sources 165

9.1.4 X-ray detectors 168

9.1.5 Wide-angle X-ray scattering and small-angle X-ray scattering 169

9.2 Applications 169

9.2.1 Example: X-ray characterization of zein–fatty acid films 170

9.2.2 Temperature-controlled WAXS 176

References 179

10 Quartz crystal microbalance with dissipation 181
Boce Zhang and Qin Wang

10.1 Background and principles 181

10.2 Instrumentation and data analysis 183

10.2.1 Sensors 183

10.2.2 Data analysis 184

10.3 Applications 185

10.4 Advantages 190

References 192

11 Focused ion beams 195
Yi Wang

11.1 Background 195

11.1.1 Introduction to the focused ion beam system 195

11.1.2 Overview of the FIB 196

11.1.3 Ion beam production 196

11.1.4 Ion–target interaction 198

11.1.5 Basic functions of the FIB system 199

11.1.6 SEM and SIM 200

11.1.7 SEM and FIB combined system 201

11.1.8 3D nanotomography with application of real-time imaging during FIB milling 201

11.1.9 3D nanostructure fabrication by FIB 202

11.2 Applications 202

11.2.1 Polymers 202

11.2.2 Biological products 203

11.2.3 Example: self-assembled protein structures 203

11.3 Limitations 207

References 214

12 X-ray computerized microtomography 215
Leilei Yin

12.1 Introduction 215

12.2 X-ray generation 215

12.3 X-ray images 217

12.4 X-ray micro-CT systems 220

12.5 Data reconstructions 226

12.6 Artifacts in micro-CT images 228

12.6.1 Ring artifacts 229

12.6.2 Center errors 230

12.6.3 Beam-hardening artifacts 230

12.6.4 Phase-contrast artifacts 231

12.7 A couple of issues in X-ray micro-CT practice 232

12.7.1 The spatial resolution, and associated issues of contrast and field of view 232

12.7.2 Localized imaging and sample-size reduction 232

References 233

Index 235

A color plate section falls between pages 194 and 195

Dr Graciela W. Padua, Department of Food Science and Human Nutrition, University of Illinois, Urbana, Illinois, USA

Dr Qin Wang, Department of Nutrition & Food Science, University of Maryland, College Park, Maryland, USA