Electrotechnologies for Extraction from Food Plants and Biomaterials (eBook)

Preface 5
Contents 7
Contributors 8
Electroporation in Biological Cell and Tissue: An Overview 11
1 Basics and Mechanisms 12
2 Influential Parameters 14
2.1 Parameters of Electric Field 14
2.1.1 Introduction of Small Molecules 15
2.1.2 Introduction of Macromolecules 16
2.1.3 Electrofusion 18
2.1.4 Irreversible Electroporation 19
2.2 Electroporation Medium Composition 19
2.3 Osmotic Pressure 20
3 From Single-Cell to Tissue 22
4 Electrodes/Shaping the Electric Field 25
5 Different Applications 26
5.1 Use in Medicine 26
5.2 Water Sterilization and Food Preservation 27
5.3 Electroporation of Bacteria and Yeast 28
5.4 Plant Protoplast Electroporation 29
5.5 Transfection of Intact Plant Tissue 30
6 Understanding Electroporation of Different Cell Types 31
6.1 Influence of Cell Membrane Fluidity 32
6.2 Influence of Cell Cytoskeleton 33
6.3 Influence of Cell Wall in Bacteria, Yeast, and Plants 33
7 Conclusions 34
Pulsed-Electric-Fields-Induced Effects in Plant Tissues: Fundamental Aspects and Perspectives of Applications 48
1 Introduction 48
2 Electric Field Effects in Plant Tissues 49
2.1 Origin of Electropermeabilization 49
2.1.1 Transmembrane Potential 50
2.1.2 Stability of Membranes and Cells 52
2.2 Electrically Induced Damage in the Cellular Tissues 53
2.2.1 Estimation of the Damage Degree 53
2.2.2 Evolution of Damage and Transient Effects 54
2.3 Optimal Energy Consumption 56
2.4 Synergetics of PEF and Thermal Treatments 57
2.5 Electroporation during Ohmic Heating 59
2.6 Damage as a Function of Pulse Protocol 60
2.6.1 Electric Field Strength and Total Treatment Time 60
2.6.2 Waveforms 61
2.6.3 Intervals Between Pulses 61
2.6.4 Pulse Duration 61
3 PEF-Enhanced Expression, Diffusion, and Drying 63
3.1 Solid--Liquid Expression from Food Plants 63
3.1.1 Example of a Laboratory Device for the Combined Pressing and PEF-Treatment 63
3.1.2 Kinetics of Solid--Liquid Expression and Quality of Juices 63
3.2 Aqueous Extraction of Solutes from Food Plants 71
3.2.1 Diffusion Kinetics and Qualitative Characteristics of Extracts 71
3.3 Osmotic Dehydration with PEF 77
3.4 Drying of Food Plants 79
3.4.1 Drying Kinetics and Moisture Diffusion Affected by PEF Cell Disintegration 79
3.4.2 Temperature Evolution 83
Moderate Electrothermal Treatments of Cellular Tissues 91
1 Introduction 91
2 Nonthermal Effects of Electric Fields on Cells with Intact Membranes 92
3 Food Engineering Applications of MEF Processes 96
3.1 Drying Rate 96
3.2 Extraction 97
3.3 Fermentation 99
4 Conclusion 100
DC Electrical Field Effects on Plant Tissues and Gels 103
1 Introduction 104
2 Electrical Apparatus and Measurement Systems 105
3 Electrification of Gels 107
3.1 Induction of Phase Transition in Gels by Electrical Fields 107
3.2 Types of Electrified Networks 110
3.3 Electrification of Alginate Gels 111
3.3.1 Influence of Alginate Gel Composition on Weight Loss During Electrification 111
3.3.2 Effect of Electrical Treatment on Mechanical Properties 112
3.3.3 Structural Changes 112
3.4 Electrification of Different Gel Types (Alginate, Agar, Agarose, Gellan) and Possible Underlying Mechanisms 113
3.5 Conclusions 114
4 Electrification of Plant Tissues 115
4.1 Resemblance between Gels and Plant Tissues 116
4.2 Expression Processes in the Food Industry and Betanin Extraction 116
4.3 Electrification of Fruit/Vegetable Pieces 119
4.4 Inhibition of Potato Browning by Electrical Field 120
4.5 Gel-Plant "Sandwiches" 122
4.6 Influences of Electrification on Intact Plant Tissues 122
4.7 Mechanism Involved in Electrifying Plant Tissues 124
5 Advantages and Future Prospects of Low Current/Low Voltage DC Electrification 124
Electro-Osmotic Dewatering (EOD) of Bio-Materials 129
1 Introduction 129
2 Theoretical Backgrounds 130
2.1 Recent Theoretical Developments 130
2.2 Principles for High Performance EOD 134
2.3 Characteristics of Materials Suitable for EOD 135
3 Applications of Electric Field for High-Performance EOD 136
3.1 Electric Field Application with Electrode Polarity Reversals 139
3.2 Interrupted or Intermittent Electric Field Application 140
3.3 Electric Field Generated by Combination of Constant Current and Constant Voltage Conditions 146
3.4 Electrode Arrangements and Configurations 147
4 EOD of Bio-Materials 153
4.1 Sewage/Activated Sludge and Biomass Sludge 153
4.2 Food Processing Products and Wastes 156
4.3 Miscellaneous Topics 159
5 Closing Remarks 160
Electrofiltration of Biomaterials 163
1 Introduction 164
2 Dewatering of Biomaterials by Press Electrofiltration 164
2.1 Force Balance 165
2.2 Filtration 166
2.3 Press Electrofiltration Versus Thermal Evaporation 170
2.4 Press Electrofiltration Versus Cross-Flow Filtration 175
3 Fractionation 176
3.1 Fractionation of Bacteria and Extracellular Enzyme Product 177
3.2 Fractionation of Highly Viscous Polysaccaride and Protein 179
3.3 Fractionation of Proteins 180
3.4 Outlook for the Fractionation with Electrofiltration 183
4 General Guidelines 184
5 Nomenclature 185
Food Industry Applications for Pulsed Electric Fields 188
1 Introduction 188
2 Historical Approach 190
3 Preservation of Foods by Pulsed Electric Fields 193
3.1 Juice 196
3.2 Milk 197
4 Improvement of Mass Transfer Process in Plant Material 200
4.1 PEF-Assisted Cell Expression and Extraction 200
4.1.1 Fruit Juice Extraction and Expression 200
4.1.2 Plant Oil Extraction 204
4.1.3 Extraction of Intracellular Compounds 205
4.2 Drying Enhancement 206
5 Softening of Plant Tissue 207
6 Stress 208
7 Meat Treatment 210
8 Wastewater Treatment 213
9 Energy Requirements and Cost-Effectiveness 214
10 Future Aspects 216
Application of High-Voltage Electrical Discharges for the Aqueous Extraction from Oilseeds and Other Plants 224
1 Introduction 224
2 High-Voltage Electrical Discharges 227
2.1 Steps of Creation 228
2.2 Condition of Apparition 228
2.3 Material and Energy 229
2.4 Interest in HVED for Various Applications 231
3 Extraction Enhanced by HVED 232
3.1 Quality of Extracted Products 233
3.2 Extraction of Soluble Molecules 233
3.3 Oil Extraction 237
4 Conclusion 240
Industrial-Scale Treatment of Biological Tissues with Pulsed Electric Fields 243
1 Introduction 243
2 Pulse Generators for Industrial Applications 244
2.1 Generator Configurations 244
2.2 Spark Gap Switches 248
2.3 Synchronization 252
2.4 Burn-Up Control Scheme 255
2.5 Screening of the Degree of Electroporation 258
3 Emerging Industrial Applications 261
3.1 Treatment of Sugar Beets 261
3.2 Treatment of Grapes 266
3.3 Conditioning of Green Biomass by Electroporation Assisted Dewatering 270
Index 276