Introduction to Food Engineering, Fourth Edition (Food Science and Technology)

Introduction to Food Engineering......Page 4
Copyright Page......Page 5
Contents......Page 12
About the Authors......Page 6
Foreword......Page 8
Preface......Page 10
1.1 Dimensions......Page 24
1.2.1 Base Units......Page 25
1.2.2 Derived Units......Page 26
1.2.3 Supplementary Units......Page 27
1.3 System......Page 33
1.4 State of a System......Page 34
1.4.1 Extensive Properties......Page 35
1.5 Density......Page 36
1.6 Concentration......Page 38
1.7 Moisture Content......Page 40
1.8 Temperature......Page 43
1.9 Pressure......Page 45
1.11 Equation of State and Perfect Gas Law......Page 49
1.12 Phase Diagram of Water......Page 50
1.13 Conservation of Mass......Page 52
1.13.1 Conservation of Mass for an Open System......Page 53
1.14 Material Balances......Page 55
1.15 Thermodynamics......Page 64
1.16.2 Second Law of Thermodynamics......Page 65
1.17 Energy......Page 66
1.19.1 Heat......Page 68
1.19.2 Work......Page 69
1.20 Energy Balance for an Open System......Page 78
1.21 A Total Energy Balance......Page 79
1.23 Area......Page 82
Problems......Page 83
List of Symbols......Page 85
Bibliography......Page 86
CHAPTER 2 Fluid Flow in Food Processing......Page 88
2.1 Liquid Transport Systems......Page 89
2.1.1 Pipes for Processing Plants......Page 90
2.1.2 Types of Pumps......Page 91
2.2 Properties of Liquids......Page 94
2.2.2 Density......Page 95
2.2.3 Viscosity......Page 96
2.3.1 The Continuity Equation......Page 104
2.3.2 Reynolds Number......Page 107
2.3.3 Entrance Region and Fully Developed Flow......Page 111
2.3.4 Velocity Profile in a Liquid Flowing Under Fully Developed Flow Conditions......Page 113
2.3.5 Forces Due to Friction......Page 119
2.4 Force Balance on a Fluid Element Flowing in a Pipe—Derivation of Bernoulli Equation......Page 123
2.5 Energy Equation for Steady Flow of Fluids......Page 130
2.5.2 Kinetic Energy......Page 133
2.5.4 Frictional Energy Loss......Page 135
2.5.5 Power Requirements of a Pump......Page 138
2.6.1 Centrifugal Pumps......Page 142
2.6.3 Pump Performance Characteristics......Page 144
2.6.4 Pump Characteristic Diagram......Page 148
2.6.5 Net Positive Suction Head......Page 149
2.6.6 Selecting a Pump for a Liquid Transport System......Page 152
2.6.7 Affinity Laws......Page 158
2.7 Flow Measurement......Page 159
2.7.1 The Pitot Tube......Page 163
2.7.2 The Orifice Meter......Page 165
2.7.4 Variable-Area Meters......Page 169
2.7.5 Other Measurement Methods......Page 170
2.8.1 Capillary Tube Viscometer......Page 171
2.8.2 Rotational Viscometer......Page 173
2.8.3 Influence of Temperature on Viscosity......Page 176
2.9.1 Properties of Non-Newtonian Fluids......Page 178
2.9.2 Velocity Profile of a Power Law Fluid......Page 184
2.9.3 Volumetric Flow Rate of a Power Law Fluid......Page 185
2.9.5 Friction Factor and Generalized Reynolds Number for Power Law Fluids......Page 186
2.9.6 Computation of Pumping Requirement of Non-newtonian Liquids......Page 189
2.10 Transport of solid foods......Page 192
2.10.1 Properties of Granular Materials and Powders......Page 193
2.10.2 Flow of Granular Foods......Page 198
Problems......Page 201
List of Symbols......Page 206
Bibliography......Page 208
3.1 Generation of Steam......Page 210
3.1.1 Steam Generation Systems......Page 211
3.1.2 Thermodynamics of Phase Change......Page 213
3.1.3 Steam Tables......Page 217
3.1.4 Steam Utilization......Page 223
3.2 Fuel Utilization......Page 227
3.2.1 Systems......Page 229
3.2.2 Mass and Energy Balance Analysis......Page 230
3.2.3 Burner Efficiencies......Page 232
3.3 Electric Power Utilization......Page 233
3.3.1 Electrical Terms and Units......Page 235
3.3.2 Ohm's Law......Page 236
3.3.3 Electric Circuits......Page 237
3.3.4 Electric Motors......Page 239
3.3.5 Electrical Controls......Page 240
3.3.6 Electric Lighting......Page 241
3.4 Process Controls in Food Processing......Page 243
3.4.1 Processing Variables and Performance Indicators......Page 245
3.4.3 Design of a Control System......Page 247
3.5.1 Temperature......Page 255
3.5.2 Liquid Level in a Tank......Page 257
3.5.3 Pressure Sensors......Page 258
3.5.4 Flow Sensors......Page 259
3.6 Dynamic Response Characteristics of Sensors......Page 260
Problems......Page 264
List of Symbols......Page 267
Bibliography......Page 268
CHAPTER 4 Heat Transfer in Food Processing......Page 270
4.1.1 Plate Heat Exchanger......Page 271
4.1.2 Tubular Heat Exchanger......Page 275
4.1.3 Scraped-surface Heat Exchanger......Page 276
4.1.4 Steam-infusion Heat Exchanger......Page 278
4.1.5 Epilogue......Page 279
4.2.1 Specific Heat......Page 280
4.2.2 Thermal Conductivity......Page 283
4.2.3 Thermal Diffusivity......Page 285
4.3.1 Conductive Heat Transfer......Page 287
4.3.2 Convective Heat Transfer......Page 290
4.3.3 Radiation Heat Transfer......Page 292
4.4 Steady-State Heat Transfer......Page 293
4.4.1 Conductive Heat Transfer in a Rectangular Slab......Page 294
4.4.2 Conductive Heat Transfer through a Tubular Pipe......Page 297
4.4.3 Heat Conduction in Multilayered Systems......Page 300
4.4.4 Estimation of Convective Heat-Transfer Coefficient......Page 308
4.4.5 Estimation of Overall Heat-Transfer Coefficient......Page 325
4.4.6 Fouling of Heat Transfer Surfaces......Page 329
4.4.7 Design of a Tubular Heat Exchanger......Page 335
4.4.8 The Effectiveness-NTU Method for Designing Heat Exchangers......Page 343
4.4.9 Design of a Plate Heat Exchanger......Page 348
4.4.10 Importance of Surface Characteristics in Radiative Heat Transfer......Page 355
4.4.11 Radiative Heat Transfer between Two Objects......Page 357
4.5 Unsteady-State Heat Transfer......Page 360
4.5.1 Importance of External versus Internal Resistance to Heat Transfer......Page 362
4.5.2 Negligible Internal Resistance to Heat Transfer (N[sub(Bi)] < 0.1)—A Lumped System Analysis......Page 363
4.5.3 Finite Internal and Surface Resistance to Heat Transfer (0.1 < N[sub(Bi)] < 40)......Page 368
4.5.5 Finite Objects......Page 371
4.5.6 Procedures to Use Temperature–Time Charts......Page 373
4.5.7 Use of f[sub(h)] and j Factors in Predicting Temperature in Transient Heat Transfer......Page 381
4.6 Electrical Conductivity of Foods......Page 389
4.7 Ohmic Heating......Page 392
4.8 Microwave Heating......Page 394
4.8.1 Mechanisms of Microwave Heating......Page 395
4.8.2 Dielectric Properties......Page 396
4.8.3 Conversion of Microwave Energy into Heat......Page 397
4.8.4 Penetration Depth of Microwaves......Page 398
4.8.5 Microwave Oven......Page 400
4.8.6 Microwave Heating of Foods......Page 401
Problems......Page 403
List of Symbols......Page 420
Bibliography......Page 422
5.1 Processing Systems......Page 426
5.1.1 Pasteurization and Blanching Systems......Page 427
5.1.2 Commercial Sterilization Systems......Page 429
5.1.3 Ultra-High Pressure Systems......Page 433
5.1.4 Pulsed Electric Field Systems......Page 435
5.2 Microbial Survivor Curves......Page 436
5.3 Influence of External Agents......Page 441
5.4 Thermal Death Time F......Page 445
5.5 Spoilage Probability......Page 446
5.6 General Method for Process Calculation......Page 447
5.6.1 Applications to Pasteurization......Page 449
5.6.2 Commercial Sterilization......Page 452
5.6.3 Aseptic Processing and Packaging......Page 455
5.7 Mathematical Methods......Page 463
5.7.1 Pouch Processing......Page 467
Problems......Page 470
List of Symbols......Page 473
Bibliography......Page 474
CHAPTER 6 Refrigeration......Page 478
6.1 Selection of a Refrigerant......Page 479
6.2 Components of a Refrigeration System......Page 483
6.2.1 Evaporator......Page 484
6.2.2 Compressor......Page 486
6.2.3 Condenser......Page 489
6.2.4 Expansion Valve......Page 491
6.3 Pressure–Enthalpy Charts......Page 493
6.3.1 Pressure–Enthalpy Tables......Page 497
6.3.2 Use of Computer-Aided Procedures to Determine Thermodynamic Properties of Refrigerants......Page 498
6.4.1 Cooling Load......Page 501
6.4.3 Condenser......Page 503
6.4.6 Refrigerant Flow Rate......Page 504
6.5 Use of Multistage Systems......Page 513
6.5.1 Flash Gas Removal System......Page 514
Problems......Page 518
Bibliography......Page 521
CHAPTER 7 Food Freezing......Page 524
7.1.1 Indirect Contact Systems......Page 525
7.1.2 Direct-Contact Systems......Page 530
7.2.1 Density......Page 533
7.2.3 Enthalpy......Page 534
7.2.5 Apparent Thermal Diffusivity......Page 536
7.3 Freezing Time......Page 537
7.3.1 Plank's Equation......Page 539
7.3.3 Pham's Method to Predict Freezing Time......Page 543
7.3.4 Prediction of Freezing Time of Finite-Shaped Objects......Page 547
7.3.6 Factors Influencing Freezing Time......Page 551
7.3.8 Thawing Time......Page 552
7.4.1 Quality Changes in Foods during Frozen Storage......Page 553
Problems......Page 557
List of Symbols......Page 561
Bibliography......Page 562
CHAPTER 8 Evaporation......Page 566
8.1 Boiling-Point Elevation......Page 568
8.2.1 Batch-Type Pan Evaporator......Page 570
8.2.3 Rising-Film Evaporator......Page 571
8.2.4 Falling-Film Evaporator......Page 572
8.2.5 Rising/Falling-Film Evaporator......Page 573
8.2.7 Agitated Thin-Film Evaporator......Page 574
8.3 Design of a Single-Effect Evaporator......Page 577
8.4 Design of a Multiple-Effect Evaporator......Page 582
8.5.1 Thermal Recompression......Page 588
Problems......Page 589
Bibliography......Page 592
9.1.1 Composition of Air......Page 594
9.1.4 Enthalpy of Dry Air......Page 595
9.2.2 Specific Heat of Water Vapor......Page 596
9.3.2 Dew-Point Temperature......Page 597
9.3.3 Humidity Ratio (or Moisture Content)......Page 598
9.3.5 Humid Heat of an Air–Water Vapor Mixture......Page 599
9.3.7 Adiabatic Saturation of Air......Page 600
9.3.8 Wet Bulb Temperature......Page 602
9.4.1 Construction of the Chart......Page 605
9.4.2 Use of Psychrometric Chart to Evaluate Complex Air-Conditioning Processes......Page 607
Problems......Page 612
List of Symbols......Page 615
Bibliography......Page 616
CHAPTER 10 Mass Transfer......Page 618
10.1 The Diffusion Process......Page 619
10.1.1 Steady-State Diffusion of Gases (and Liquids) through Solids......Page 622
10.1.2 Convective Mass Transfer......Page 623
10.1.3 Laminar Flow over a Flat Plate......Page 627
10.1.5 Laminar Flow in a Pipe......Page 631
10.1.7 Mass Transfer for Flow over Spherical Objects......Page 632
10.2 Unsteady-State Mass Transfer......Page 633
10.2.1 Transient-State Diffusion......Page 634
10.2.2 Diffusion of Gases......Page 639
Problems......Page 642
List of Symbols......Page 644
Bibliography......Page 645
CHAPTER 11 Membrane Separation......Page 646
11.1 Electrodialysis Systems......Page 648
11.2 Reverse Osmosis Membrane Systems......Page 652
11.3 Membrane Performance......Page 659
11.4 Ultrafiltration Membrane Systems......Page 660
11.5 Concentration Polarization......Page 662
11.6 Types of Reverse-Osmosis and Ultrafiltration Systems......Page 668
11.6.3 Spiral-Wound......Page 669
Problems......Page 672
List of Symbols......Page 673
Bibliography......Page 674
12.1 Basic Drying Processes......Page 676
12.1.1 Water Activity......Page 677
12.1.2 Moisture Diffusion......Page 680
12.1.4 Heat and Mass Transfer......Page 681
12.2.1 Tray or Cabinet Dryers......Page 683
12.2.2 Tunnel Dryers......Page 684
12.2.3 Puff-Drying......Page 685
12.2.5 Spray Drying......Page 686
12.2.6 Freeze-Drying......Page 687
12.3.1 Mass and Energy Balance......Page 688
12.3.2 Drying-Time Prediction......Page 693
Problems......Page 703
List of Symbols......Page 708
Bibliography......Page 709
13.1.1 Operating Equations......Page 712
13.1.2 Mechanisms of Filtration......Page 718
13.1.3 Design of a Filtration System......Page 719
13.2.1 Sedimentation Velocities for Low-Concentration Suspensions......Page 722
13.2.2 Sedimentation in High-Concentration Suspensions......Page 725
13.3.2 Rate of Separation......Page 728
13.3.3. Liquid-Liquid Separation......Page 730
13.4 Mixing......Page 732
13.4.1 Agitation Equipment......Page 734
13.4.2 Power Requirements of Impellers......Page 737
Problems......Page 741
List of Symbols......Page 742
Bibliography......Page 743
14.1 Introduction and Background......Page 744
14.2 Basic Principles of Extrusion......Page 745
14.3 Extrusion Systems......Page 752
14.3.1 Cold Extrusion......Page 753
14.3.2 Extrusion Cooking......Page 754
14.3.3 Single Screw Extruders......Page 755
14.3.4 Twin-Screw Extruders......Page 757
14.4 Extrusion System Design......Page 758
14.5 Design of More Complex Systems......Page 763
Problems......Page 764
Bibliography......Page 765
15.1 Introduction......Page 768
15.2 Food Protection......Page 769
15.3 Product Containment......Page 770
15.6 Mass Transfer in Packaging Materials......Page 771
15.6.1 Permeability of Packaging Material to "Fixed" Gases......Page 774
15.7 Innovations in Food Packaging......Page 777
15.7.2 Active Packaging......Page 778
15.7.3 Intelligent Packaging......Page 779
15.8.1 Scientific Basis for Evaluating Shelf Life......Page 781
Problems......Page 789
List of Symbols......Page 790
Bibliography......Page 791
Table A.1.1: SI Prefixes......Page 794
Table A.1.2: Useful Conversion Factors......Page 797
Table A.1.3: Conversion Factors for Pressure......Page 799
Table A.2.1: Specific Heat of Foods......Page 800
Table A.2.2: Thermal Conductivity of Selected Food Products......Page 801
Table A.2.3: Thermal Diffusivity of Some Foodstuffs......Page 803
Table A.2.4: Viscosity of Liquid Foods......Page 804
Table A.2.6: Approximate Heat Evolution Rates of Fresh Fruits and Vegetables When Stored at Temperatures Shown......Page 805
Table A.2.7: Enthalpy of Frozen Foods......Page 807
Table A.2.8: Composition Values of Selected Foods......Page 808
Table A.2.9: Coefficients to Estimate Food Properties......Page 809
Table A.3.1: Physical Properties of Metals......Page 810
Table A.3.2: Physical Properties of Nonmetals......Page 811
Table A.3.3: Emissivity of Various Surfaces......Page 813
Table A.4.1: Physical Properties of Water at the Saturation Pressure......Page 815
Table A.4.2: Properties of Saturated Steam......Page 816
Table A.4.3: Properties of Superheated Steam......Page 818
Table A.4.4: Physical Properties of Dry Air at Atmospheric Pressure......Page 819
Figure A.5.1: Psychrometric chart for high temperatures......Page 820
Figure A.5.2: Psychrometric chart for low temperatures......Page 821
Figure A.6.1: Pressure–enthalpy diagram for Refigerant 12......Page 822
Table A.6.1: Properties of Saturated Liquid and Vapor R-12......Page 823
Figure A.6.2: Pressure–enthalpy diagram of superheated R-12 vapor......Page 826
Table A.6.2: Properties of Saturated Liquid and Vapor R-717 (Ammonia)......Page 827
Figure A.6.3: Pressure–enthalpy diagram of superheated R-717 (ammonia) vapor......Page 830
Table A.6.3: Properties of Saturated Liquid and Vapor R-134a......Page 831
Figure A.6.4: Pressure–enthalpy diagram of R-134a......Page 834
Figure A.6.5: Pressure–enthalpy diagram of R-134a (expanded scale)......Page 835
A.7 Symbols for Use in Drawing Food Engineering Process Equipment......Page 836
Table A.8.1: Numerical Data, and Area/Volume of Objects......Page 841
Figure A.8.1: Temperature at geometric center of a sphere (expanded scale)......Page 842
Figure A.8.2: Temperature at the axis of an infinitely long cylinder (expanded scale)......Page 843
Figure A.8.3: Temperature at the midplane of an infinite slab (expanded scale)......Page 844
A.9 Dimensional Analysis......Page 845
Table A.9.1: Dimensions of selected experimental variables......Page 846
Bibliography......Page 849
C......Page 852
E......Page 853
F......Page 854
I......Page 855
N......Page 856
P......Page 857
R......Page 858
S......Page 859
V......Page 860
Z......Page 861
Food Science and Technology: International Series......Page 862