introductio to food engineering fourth editionPDF电子书下载

CHAPTER 1 Introduction 1

1.1 Dimensions 1

1.2 Engineering Units 2

1.2.1 Base Units 2

1.2.2 Derived Units 3

1.2.3 Supplementary Units 4

1.3 System 10

1.4 State of a System 11

1.4.1 Extensive Properties 12

1.4.2 Intensive Properties 13

1.5 Density 13

1.6 Concentration 15

1.7 Moisture Content 17

1.8 Temperature 20

1.9 Pressure 22

1.10 Enthalpy 26

1.11 Equation of State and Perfect Gas Law 26

1.12 Phase Diagram of Water 27

1.13 Conservation of Mass 29

1.13.1 Conservation of Mass for an Open System 30

1.13.2 Conservation of Mass for a Closed System 32

1.14 Material Balances 32

1.15 Thermodynamics 41

1.16 Laws of Thermodynamics 42

1.16.1 First Law of Thermodynamics 42

1.16.2 Second Law of Thermodynamics 42

1.17 Energy 43

1.18 Energy Balance 45

1.19 Energy Balance for a Closed System 45

1.19.1 Heat 45

1.19.2 Work 46

1.20 Energy Balance for an Open System 55

1.20.1 Energy Balance for Steady Flow Systems 56

1.21 A Total Energy Balance 56

1.22 Power 59

1.23 Area 59

Problems 60

List of Symbols 62

Bibliography 63

CHAPTER 2 Fluid Flow in Food Processing 65

2.1 Liquid Transport Systems 66

2.1.1 Pipes for Processing Plants 67

2.1.2 Types of Pumps 68

2.2 Properties of Liquids 71

2.2.1 Terminology Used in Material Response to Stress 72

2.2.2 Density 72

2.2.3 Viscosity 73

2.3 Handling Systems for Newtonian Liquids 81

2.3.1 The Continuity Equation 81

2.3.2 Reynolds Number 84

2.3.3 Entrance Region and Fully Developed Flow 88

2.3.4 Velocity Profile in a Liquid Flowing Under Fully Developed Flow Conditions 90

2.3.5 Forces Due to Friction 96

2.4 Force Balance on a Fluid Element Flowing in a Pipe—Derivation of Bernoulli Equation 100

2.5 Energy Equation for Steady Flow of Fluids 107

2.5.1 Pressure Energy 110

2.5.2 Kinetic Energy 110

2.5.3 Potential Energy 112

2.5.4 Frictional Energy Loss 112

2.5.5 Power Requirements of a Pump 115

2.6 Pump Selection and Performance Evaluation 119

2.6.1 Centrifugal Pumps 119

2.6.2 Head 121

2.6.3 Pump Performance Characteristics 121

2.6.4 Pump Characteristic Diagram 125

2.6.5 Net Positive Suction Head 126

2.6.6 Selecting a Pump for a Liquid Transport System 129

2.6.7 Affinity Laws 135

2.7 Flow Measurement 136

2.7.1 The Pitot Tube 140

2.7.2 The Orifice Meter 142

2.7.3 The Venturi Meter 146

2.7.4 Variable-Area Meters 146

2.7.5 Other Measurement Methods 147

2.8 Measurement of Viscosity 148

2.8.1 Capillary Tube Viscometer 148

2.8.2 Rotational Viscometer 150

2.8.3 Influence of Temperature on Viscosity 153

2.9 Flow Characteristics of Non-Newtonian Fluids 155

2.9.1 Properties of Non-Newtonian Fluids 155

2.9.2 Velocity Profile of a Power Law Fluid 161

2.9.3 Volumetric Flow Rate of a Power Law Fluid 162

2.9.4 Average Velocity in a Power Law Fluid 163

2.9.5 Friction Factor and Generalized Reynolds Number for Power Law Fluids 163

2.9.6 Computation of Pumping Requirement of Non-newtonian Liquids 166

2.10 Transport of solid foods 169

2.10.1 Properties of Granular Materials and Powders 170

2.10.2 Flow of Granular Foods 175

Problems 178

List of Symbols 183

Bibliography 185

CHAPTER 3 Energy and Controls in Food Processes 187

3.1 Generation of Steam 187

3.1.1 Steam Generation Systems 188

3.1.2 Thermodynamics of Phase Change 190

3.1.3 Steam Tables 194

3.1.4 Steam Utilization 200

3.2 Fuel Utilization 204

3.2.1 Systems 206

3.2.2 Mass and Energy Balance Analysis 207

3.2.3 Burner Efficiencies 209

3.3 Electric Power Utilization 210

3.3.1 Electrical Terms and Units 212

3.3.2 Ohm’s Law 213

3.3.3 Electric Circuits 214

3.3.4 Electric Motors 216

3.3.5 Electrical Controls 217

3.3.6 Electric Lighting 218

3.4 Process Controls in Food Processing 220

3.4.1 Processing Variables and Performance Indicators 222

3.4.2 Input and Output Signals to Control Processes 224

3.4.3 Design of a Control System 224

3.5 Sensors 232

3.5.1 Temperature 232

3.5.2 Liquid Level in a Tank 234

3.5.3 Pressure Sensors 235

3.5.4 Flow Sensors 236

3.5.5 Glossary of Terms Important in Data Acquisition 237

3.6 Dynamic Response Characteristics of Sensors 237

Problems 241

List of Symbols 244

Bibliography 245

CHAPTER 4 Heat Transfer in Food Processing 247

4.1 Systems for Heating and Cooling Food Products 248

4.1.1 Plate Heat Exchanger 248

4.1.2 Tubular Heat Exchanger 252

4.1.3 Scraped-surface Heat Exchanger 253

4.1.4 Steam-infusion Heat Exchanger 255

4.1.5 Epilogue 256

4.2 Thermal Properties of Foods 257

4.2.1 Specific Heat 257

4.2.2 Thermal Conductivity 260

4.2.3 Thermal Diffusivity 262

4.3 Modes of Heat Transfer 264

4.3.1 Conductive Heat Transfer 264

4.3.2 Convective Heat Transfer 267

4.3.3 Radiation Heat Transfer 269

4.4 Steady-State Heat Transfer 270

4.4.1 Conductive Heat Transfer in a Rectangular Slab 271

4.4.2 Conductive Heat Transfer through a Tubular Pipe 274

4.4.3 Heat Conduction in Multilayered Systems 277

4.4.4 Estimation of Convective Heat-Transfer Coefficient 285

4.4.5 Estimation of Overall Heat-Transfer Coefficient 302

4.4.6 Fouling of Heat Transfer Surfaces 306

4.4.7 Design of a Tubular Heat Exchanger 312

4.4.8 The Effectiveness-NTU Method for Designing Heat Exchangers 320

4.4.9 Design of a Plate Heat Exchanger 325

4.4.10 Importance of Surface Characteristics in Radiative Heat Transfer 332

4.4.11 Radiative Heat Transfer between Two Objects 334

4.5 Unsteady-State Heat Transfer 337

4.5.1 Importance of External versus Internal Resistance to Heat Transfer 339

4.5.2 Negligible Internal Resistance to Heat Transfer（NBi＜0.1）—A Lumped System Analysis 340

4.5.3 Finite Internal and Surface Resistance to Heat Transfer（0.1＜NBi＜40） 345

4.5.4 Negligible Surface Resistance to Heat Transfer（NBi≥40） 348

4.5.5 Finite Objects 348

4.5.6 Procedures to Use Temperature-Time Charts 350

4.5.7 Use of f h and j Factors in Predicting Temperature in Transient Heat Transfer 358

4.6 Electrical Conductivity of Foods 366

4.7 Ohmic Heating 369

4.8 Microwave Heating 371

4.8.1 Mechanisms of Microwave Heating 372

4.8.2 Dielectric Properties 373

4.8.3 Conversion of Microwave Energy into Heat 374

4.8.4 Penetration Depth of Microwaves 375

4.8.5 Microwave Oven 377

4.8.6 Microwave Heating of Foods 378

Problems 380

List of Symbols 397

Bibliography 399

CHAPTER 5 Preservation Processes 403

5.1 Processing Systems 403

5.1.1 Pasteurization and Blanching Systems 404

5.1.2 Commercial Sterilization Systems 406

5.1.3 Ultra-High Pressure Systems 410

5.1.4 Pulsed Electric Field Systems 412

5.1.5 Alternative Preservation Systems 413

5.2 Microbial Survivor Curves 413

5.3 Influence of External Agents 418

5.4 Thermal Death Time F 422

5.5 Spoilage Probability 423

5.6 General Method for Process Calculation 424

5.6.1 Applications to Pasteurization 426

5.6.2 Commercial Sterilization 429

5.6.3 Aseptic Processing and Packaging 432

5.7 Mathematical Methods 440

5.7.1 Pouch Processing 444

Problems 447

List of Symbols 450

Bibliography 451

CHAPTER 6 Refrigeration 455

6.1 Selection of a Refrigerant 456

6.2 Components of a Refrigeration System 460

6.2.1 Evaporator 461

6.2.2 Compressor 463

6.2.3 Condenser 466

6.2.4 Expansion Valve 468

6.3 Pressure-Enthalpy Charts 470

6.3.1 Pressure-Enthalpy Tables 474

6.3.2 Use of Computer-Aided Procedures to Determine Thermodynamic Properties of Refrigerants 475

6.4 Mathematical Expressions Useful in Analysis of Vapor-Compression Refrigeration 478

6.4.1 Cooling Load 478

6.4.2 Compressor 480

6.4.3 Condenser 480

6.4.4 Evaporator 481

6.4.5 Coefficient of Performance 481

6.4.6 Refrigerant Flow Rate 481

6.5 Use of Multistage Systems 490

6.5.1 Flash Gas Removal System 491

Problems 495

List of Symbols 498

Bibliography 498

CHAPTER 7 Food Freezing 501

7.1 Freezing Systems 502

7.1.1 Indirect Contact Systems 502

7.1.2 Direct-Contact Systems 507

7.2 Frozen-Food Properties 510

7.2.1 Density 510

7.2.2 Thermal Conductivity 511

7.2.3 Enthalpy 511

7.2.4 Apparent Specific Heat 513

7.2.5 Apparent Thermal Diffusivity 513

7.3 FreezingTime 514

7.3.1 Plank’s Equation 516

7.3.2 Other Freezing-Time Prediction Methods 520

7.3.3 Pham’s Method to Predict Freezing Time 520

7.3.4 Prediction of Freezing Time of Finite-Shaped Objects 524

7.3.5 Experimental Measurement of Freezing Time 528

7.3.6 Factors Influencing Freezing Time 528

7.3.7 Freezing Rate 529

7.3.8 Thawing Time 529

7.4 Frozen-Food Storage 530

7.4.1 Quality Changes in Foods during Frozen Storage 530

Problems 534

List of Symbols 538

Bibliography 539

CHAPTER 8 Evaporation 543

8.1 Boiling-Point Elevation 545

8.2 Types of Evaporators 547

8.2.1 Batch-Type Pan Evaporator 547

8.2.2 Natural Circulation Evaporators 548

8.2.3 Rising-Film Evaporator 548

8.2.4 Falling-Film Evaporator 549

8.2.5 Rising/Falling-Film Evaporator 550

8.2.6 Forced-Circulation Evaporator 551

8.2.7 Agitated Thin-Film Evaporator 551

8.3 Design of a Single-Effect Evaporator 554

8.4 Design of a Multiple-Effect Evaporator 559

8.5 Vapor Recompression Systems 565

8.5.1 Thermal Recompression 565

8.5.2 Mechanical Vapor Recompression 566

Problems 566

List of Symbols 569

Bibliography 569

CHAPTER 9 Psychrometrics 571

9.1 Properties of Dry Air 571

9.1.1 Composition of Air 571

9.1.2 Specific Volume of Dry Air 572

9.1.3 Specific Heat of Dry Air 572

9.1.4 Enthalpy of Dry Air 572

9.1.5 Dry Bulb Temperature 573

9.2 Properties of Water Vapor 573

9.2.1 Specific Volume of Water Vapor 573

9.2.2 Specific Heat of Water Vapor 573

9.2.3 Enthalpy of Water Vapor 574

9.3 Properties of Air-Vapor Mixtures 574

9.3.1 Gibbs-Dalton Law 574

9.3.2 Dew-Point Temperature 574

9.3.3 Humidity Ratio（or Moisture Content） 575

9.3.4 Relative Humidity 576

9.3.5 Humid Heat of an Air-Water Vapor Mixture 576

9.3.6 Specific Volume 577

9.3.7 Adiabatic Saturation of Air 577

9.3.8 Wet Bulb Temperature 579

9.4 The Psychrometric Chart 582

9.4.1.Construction of the Chart 582

9.4.2 Use of Psychrometric Chart to Evaluate Complex Air-Conditioning Processes 584

Problems 589

List of Symbols 592

Bibliography 593

CHAPTER 10 Mass Transfer 595

10.1 The Diffusion Process 596

10.1.1 Steady-State Diffusion of Gases（and Liquids）through Solids 599

10.1.2 Convective Mass Transfer 600

10.1.3 Laminar Flow over a Flat Plate 604

10.1.4 Turbulent Flow Past a Flat Plate 608

10.1.5 Laminar Flow in a Pipe 608

10.1.6 Turbulent Flow in a Pipe 609

10.1.7 Mass Transfer for Flow over Spherical Objects 609

10.2 Unsteady-State Mass Transfer 610

10.2.1 Transient-State Diffusion 611

10.2.2 Diffusion of Gases 616

Problems 619

List of Symbols 621

Bibliography 622

CHAPTER 11 Membrane Separation 623

11.1 Electrodialysis Systems 625

11.2 Reverse Osmosis Membrane Systems 629

11.3 Membrane Performance 636

11.4 Ultrafiltration Membrane Systems 637

11.5 Concentration Polarization 639

11.6 Types of Reverse-Osmosis and Ultrafiltration Systems 645

11.6.1 Plate and Frame 646

11.6.2 Tubular 646

11.6.3 Spiral-Wound 646

11.6.4 Hollow-Fiber 649

Problems 649

List of Symbols 650

Bibliography 651

CHAPTER 12 Dehydration 653

12.1 Basic Drying Processes 653

12.1.1 Water Activity 654

12.1.2 Moisture Diffusion 657

12.1.3 Drying-Rate Curves 658

12.1.4 Heat and Mass Transfer 658

12.2 Dehydration systems 660

12.2.1 Tray or Cabinet Dryers 660

12.2.2 Tunnel Dryers 661

12.2.3 Puff-Drying 662

12.2.4 Fluidized-Bed Drying 663

12.2.5 Spray Drying 663

12.2.6 Freeze-Drying 664

12.3 Dehydration System Design 665

12.3.1 Mass and Energy Balance 665

12.3.2 Drying-Time Prediction 670

Problems 680

List of Symbols 685

Bibliography 686

CHAPTER 13 Supplemental Processes 689

13.1 Filtration 689

13.1.1 Operating Equations 689

13.1.2 Mechanisms of Filtration 695

13.1.3 Design of a Filtration System 696

13.2 Sedimentation 699

13.2.1 Sedimentation Velocities for Low-Concentration Suspensions 699

13.2.2 Sedimentation in High-Concentration Suspensions 702

13.3 Centrifugation 705

13.3.1 Basic Equations 705

13.3.2 Rate of Separation 705

13.3.3. Liquid-Liquid Separation 707

13.3.4 Particle-Gas Separation 709

13.4 Mixing 709

13.4.1 Agitation Equipment 711

13.4.2 Power Requirements of Impellers 714

Problems 718

List of Symbols 719

Bibliography 720

CHAPTER 14 Extrusion Processes for Foods 721

14.1 Introduction and Background 721

14.2 Basic Principles of Extrusion 722

14.3 Extrusion Systems 729

14.3.1 Cold Extrusion 730

14.3.2 Extrusion Cooking 731

14.3.3 Single Screw Extruders 732

14.3.4 Twin-Screw Extruders 734

14.4 Extrusion System Design 735

14.5 Design of More Complex Systems 740

Problems 741

List of Symbols 742

Bibliography 742

CHAPTER 15 Packaging Concepts 745

15.1 Introduction 745

15.2 Food Protection 746

15.3 Product Containment 747

15.4 Product Communication 748

15.5 Product Convenience 748

15.6 Mass Transfer in Packaging Materials 748

15.6.1 Permeability of Packaging Material to“Fixed”Gases 751

15.7 Innovations in Food Packaging 754

15.7.1 Passive Packaging 755

15.7.2 Active Packaging 755

15.7.3 Intelligent Packaging 756

15.8 Food Packaging and Product Shelf-life 758

15.8.1 Scientityc Basis for Evaluating Shelf Life 758

15.9 Summary 766

Problems 766

List of Symbols 767

Bibliography 768

Appendices 771

A.1 SI System of Units and Conversion Factors 771

A.1.1 Rules for Using SI Units 771

Table A.1.1：SI Prefixes 771

Table A.1.2：Useful Conversion Factors 774

Table A.1.3：Conversion Factors for Pressure 776

A.2 Physical Properties of Foods 777

Table A.2.1：Specific Heat of Foods 777

Table A.2.2：Thermal Conductivity of Selected Food Products 778

Table A.2.3：Thermal Diffusivity of Some Foodstuffs 780

Table A.2.4：Viscosity of Liquid Foods 781

Table A.2.5：Properties of Ice as a Function of Temperature 782

Table A.2.6：Approximate Heat Evolution Rates of Fresh Fruits and Vegetables When Stored at Temperatures Shown 782

Table A.2.7：Enthalpy of Frozen Foods 784

Table A.2.8：Composition Values of Selected Foods 785

Table A.2.9：Coefficients to Estimate Food Properties 786

A.3 Physical Properties of Nonfood Materials 787

Table A.3.1：Physical Properties of Metals 787

Table A.3.2：Physical Properties of Nonmetals 788

Table A.3.3：Emissivity of Various Surfaces 790

A.4 Physical Properties of Water and Air 792

Table A.4.1：Physical Properties of Water at the Saturation Pressure 792

Table A.4.2：Properties of Saturated Steam 793

Table A.4.3：Properties of Superheated Steam 795

Table A.4.4：Physical Properties of Dry Air at Atmospheric Pressure 796

A.5 Psychrometric Charts 797

Figure A.5.1：Psychrometric chart for high temperatures 797

Figure A.5.2：Psychrometric chart for low temperatures 798

A.6 Pressure-Enthalpy Data 799

Figure A.6.1：Pressure-enthalpy diagram for Refigerant 12 799

Table A.6.1：Properties of Saturated Liquid and Vapor R-12 800

Figure A.6.2：Pressure-enthalpy diagram of superheated R-12 vapor 803

Table A.6.2：Properties of Saturated Liquid and Vapor R-717（Ammonia） 804

Figure A.6.3：Pressure-enthalpy diagram of superheated R-717（ammonia）vapor 807

Table A.6.3：Properties of Saturated Liquid and Vapor R-134a 808

Figure A.6.4：Pressure-enthalpy diagram of R-134a 811

Figure A.6.5：Pressure-enthalpy diagram of R-134a（expanded scale） 812

A.7 Symbols for Use in Drawing Food Engineering Process Equipment 813

A.8 Miscellaneous 818

Table A.8.1：Numerical Data，and Area/Volume of Objects 818

Figure A.8.1：Temperature at geometric center of a sphere（expanded scale） 819

Figure A.8.2：Temperature at the axis of an infinitely long cylinder（expanded scale） 820

Figure A.8.3：Temperature at the midplane of an infinite slab（expanded scale） 821

A.9 Dimensional Analysis 822

Table A.9.1：Dimensions of selected experimental variables 823

Bibliography 826

Index 829

Food Science and Technology：International Series 839