Food Process Engineering and Technology

Front Cover......Page 1
Food Process Engineering and Technology......Page 4
Copyright Page......Page 5
Contents......Page 6
Introduction – Food is Life......Page 18
1.1 Introduction......Page 24
1.2.1 Definitions......Page 25
1.2.2 Rheological models......Page 26
1.3 Thermal properties......Page 27
1.5 Structure......Page 28
1.6.1 The importance of water in foods......Page 30
1.6.3 Water activity: prediction......Page 31
1.6.4 Water vapor sorption isotherms......Page 33
1.7.1 The glassy state in foods......Page 36
1.7.2 Glass transition temperature......Page 37
2.2.1 Viscosity......Page 44
2.2.2 Fluid flow regimes......Page 45
2.2.3a Laminar flow in a cylindrical channel (pipe or tube)......Page 47
2.2.3b Laminar fluid flow on flat surfaces and channels......Page 50
2.2.3c Laminar fluid flow around immersed particles......Page 51
2.2.4 Turbulent fluid flow......Page 53
2.2.4a Turbulent Newtonian fluid flow in a cylindrical channel (tube or pipe)......Page 54
2.2.4b Turbulent fluid flow around immersed particles......Page 56
2.3.1 Types of fluid flow behavior......Page 57
2.3.2 Non-Newtonian fluid flow in pipes......Page 58
2.4.1 Energy relations, the Bernoulli Equation......Page 60
2.4.2 Pumps: Types and operation......Page 63
2.4.3 Pump selection......Page 69
2.4.4 Ejectors......Page 72
2.5.1 Introduction......Page 73
2.5.2 Flow properties of particulate solids......Page 74
2.5.3 Fluidization......Page 79
2.5.4 Pneumatic transport......Page 82
3.2.1 Basic laws of transport......Page 86
3.3.1 The Fourier and Fick laws......Page 87
3.3.2 Integration of Fourier\'s and Fick\'s laws for steady-state conductive transport......Page 88
3.3.3 Thermal conductivity, thermal diffusivity and molecular diffusivity......Page 90
3.3.4 Examples of steady-state conductive heat and mass transfer processes......Page 93
3.4.1 Film (or surface) heat and mass transfer coefficients......Page 98
3.4.2 Empirical correlations for convection heat and mass transfer......Page 101
3.4.3 Steady-state interphase mass transfer......Page 104
3.5.1 The 2nd Fourier and Fick laws......Page 106
3.5.2 Solution of Fourier\'s second law equation for an infinite slab......Page 107
3.5.3 Transient conduction transfer in finite solids......Page 109
3.5.4 Transient convective transfer in a semi-infinite body......Page 111
3.5.5 Unsteady state convective transfer......Page 112
3.6.1 Interaction between matter and thermal radiation......Page 113
3.6.2 Radiation heat exchange between surfaces......Page 114
3.7.1 Overall coefficient of heat transfer......Page 117
3.7.2 Heat exchange between flowing fluids......Page 119
3.7.3 Fouling......Page 121
3.7.4 Heat exchangers in the food process industry......Page 122
3.8 Microwave heating......Page 124
3.8.1 Basic principles of microwave heating......Page 125
3.9.1 Introduction......Page 126
3.9.2 Basic principles......Page 127
3.9.3 Applications and equipment......Page 129
4.1 Introduction......Page 132
4.2.2 Reaction order......Page 133
4.2.3 Effect of temperature on reaction kinetics......Page 136
4.3.1 Enzyme-catalyzed reactions......Page 138
4.3.2 Growth of microorganisms......Page 139
4.4.1 Reactors in food processing......Page 140
4.4.2 Residence time distribution......Page 141
5.2 Basic concepts......Page 146
5.3.2 Feed-forward control......Page 148
5.4 The block diagram......Page 149
5.5.1 First order response......Page 150
5.5.2 Second order systems......Page 152
5.6.1 On-off (binary) control......Page 153
5.6.2 Proportional (P) control......Page 155
5.6.3 Integral (I) control......Page 156
5.6.5 Proportional-integral-differential (PID) control......Page 157
5.6.6 Optimization of control......Page 158
5.7.1 The sensors (measuring elements)......Page 159
5.7.3 The actuators......Page 166
6.1 Introduction......Page 170
6.2.1 Defining the size of a single particle......Page 171
6.2.2 Particle size distribution in a population of particles; defining a \'mean particle size\'......Page 172
6.2.3 Mathematical models of PSD......Page 175
6.2.4 A note on particle shape......Page 177
6.3.3 Energy consumption......Page 180
6.4 Size reduction of solids, equipment and methods......Page 182
6.4.1 Impact mills......Page 183
6.4.2 Pressure mills......Page 184
6.4.3 Attrition mills......Page 185
6.4.4 Cutters and choppers......Page 187
7.2.1 Types of blenders......Page 192
7.2.2 Flow patterns in fluid mixing......Page 194
7.2.3 Energy input in fluid mixing......Page 195
7.3 Kneading......Page 198
7.5.2 Quality of mixing, the concept of \'mixedness\'......Page 201
7.5.3 Equipment for mixing particulate solids......Page 204
7.6.1 Basic principles......Page 206
7.6.2 Homogenizers......Page 208
8.1 Introduction......Page 212
8.2 Depth filtration......Page 213
8.3.1 Mechanisms......Page 215
8.3.2 Rate of filtration......Page 216
8.3.3 Optimization of the filtration cycle......Page 221
8.3.4 Characteristics of filtration cakes......Page 222
8.3.5 The role of cakes in filtration......Page 223
8.4.2 Barrier (surface) filters......Page 224
8.5.2 Mechanisms......Page 228
8.5.3 Applications and equipment......Page 230
9.1 Introduction......Page 234
9.2.1 The continuous settling tank......Page 235
9.2.2 From the settling tank to the tubular centrifuge......Page 237
9.2.3 The baffled settling tank and the disc-bowl centrifuge......Page 240
9.2.4 Liquid–liquid separation......Page 241
9.3 Centrifuges......Page 243
9.3.1 Tubular centrifuges......Page 244
9.3.2 Disc-bowl centrifuges......Page 245
9.3.4 Basket centrifuges......Page 247
9.4 Cyclones......Page 248
10.1 Introduction......Page 250
10.2 Tangential filtration......Page 251
10.3.1 Solvent transport......Page 252
10.3.2 Solute transport; sieving coefficient and rejection......Page 254
10.3.3 Concentration polarization and gel polarization......Page 255
10.4.1 Basic concepts......Page 258
10.4.2 Solvent transport in reverse osmosis......Page 259
10.5.1 Membrane materials......Page 262
10.5.2 Membrane configurations......Page 264
10.6.2 Ultrafiltration......Page 266
10.6.3 Nanofiltration and reverse osmosis......Page 268
10.7 Electrodialysis......Page 270
11.1 Introduction......Page 276
11.2.1 Definitions......Page 278
11.2.4 Multistage extraction......Page 279
11.2.5 Stage efficiency......Page 283
11.2.6 Solid–liquid extraction systems......Page 285
11.3.1 Basic principles......Page 288
11.3.2 Supercritical fluids as solvents......Page 289
11.3.3 Supercritical extraction systems......Page 290
11.3.4 Applications......Page 292
11.4.2 Applications......Page 293
12.1 Introduction......Page 296
12.2 Equilibrium conditions......Page 297
12.3 Batch adsorption......Page 299
12.4 Adsorption in columns......Page 304
12.5.1 Basic principles......Page 305
12.5.2 Properties of ion exchangers......Page 306
12.5.3 Application: Water softening using ion exchange......Page 309
12.5.4 Application: Reduction of acidity in fruit juices......Page 310
13.2 Vapor–liquid equilibrium (VLE)......Page 312
13.3 Continuous flash distillation......Page 315
13.4 Batch (differential) distillation......Page 318
13.5.1 Basic concepts......Page 321
13.5.2 Analysis and design of the column......Page 322
13.5.4 Tray configuration......Page 327
13.5.6 Heating with live steam......Page 328
13.5.7 Energy considerations......Page 329
13.6 Steam distillation......Page 330
13.7 Distillation of wines and spirits......Page 331
14.1 Introduction......Page 334
14.2.1 Nucleation......Page 335
14.2.2 Crystal growth......Page 337
14.3.1 Equipment......Page 340
14.3.2 Processes......Page 342
14.4.2 Mechanism and kinetics......Page 345
15.1 Introduction......Page 350
15.2.1 Structure......Page 351
15.2.2 Operation......Page 352
15.2.3 Flow models, extruder throughput......Page 354
15.3.1 Structure......Page 357
15.3.2 Operation......Page 359
15.4.1 Physical effects......Page 360
15.4.2 Chemical effect......Page 361
15.5.2 Expanded snacks......Page 362
15.5.3 Ready-to-eat cereals......Page 363
15.5.5 Other extruded starchy and cereal products......Page 364
15.5.7 Confectionery and chocolate......Page 365
15.5.8 Pet foods......Page 366
16.2 Food preservation processes......Page 368
16.4 Packaging......Page 370
17.1 Introduction......Page 372
17.2.1 The concept of decimal reduction time......Page 373
17.2.2 Effect of the temperature on the rate of thermal destruction/inactivation......Page 375
17.3 Lethality of thermal processes......Page 377
17.4 Optimization of thermal processes with respect to quality......Page 380
17.5.1 In-package thermal processing......Page 381
17.5.2 In-flow thermal processing......Page 386
18.2 Thermal processing in hermetically closed containers......Page 392
18.2.1 Filling into the cans......Page 393
18.2.2 Expelling air from the head-space......Page 395
18.2.3 Sealing......Page 396
18.2.4 Heat processing......Page 397
18.3.2 Bulk heating – holding – bulk cooling – cold filling – sealing......Page 403
18.3.3 Aseptic processing......Page 405
19.1 Introduction......Page 408
19.2.1 Temperature and chemical activity......Page 409
19.2.2 Effect of low temperature on enzymatic spoilage......Page 412
19.2.3 Effect of low temperature on microorganisms......Page 413
19.2.4 Effect of low temperature on biologically active (respiring) tissue......Page 415
19.2.5 The effect of low temperature on physical properties......Page 416
19.3 Freezing......Page 417
19.3.1 Phase transition, freezing point......Page 418
19.3.2 Freezing kinetics, freezing time......Page 419
19.3.3 Effect of freezing and frozen storage on product quality......Page 425
20.1.1 Mechanical refrigeration......Page 430
20.1.2 Refrigerants......Page 435
20.1.3 Distribution and delivery of refrigeration......Page 436
20.2 Cold storage and refrigerated transport......Page 437
20.3.1 Blast cooling......Page 440
20.3.2 Contact freezers......Page 442
20.3.4 Evaporative cooling......Page 443
21.1 Introduction......Page 446
21.2 Material and energy balance......Page 447
21.3 Heat transfer......Page 449
21.3.1 The overall coefficient of heat transfer U......Page 450
21.3.2 The temperature difference T[sub(s)] – T[sub(c)] (ΔT)......Page 453
21.4 Energy management......Page 457
21.4.1 Multiple-effect evaporation......Page 458
21.4.2 Vapor recompression......Page 463
21.5 Condensers......Page 464
21.6.1 Open pan batch evaporator......Page 465
21.6.3 Evaporators with tubular heat exchangers......Page 466
21.6.5 Boiling film evaporators......Page 468
21.7.1 Thermal effects......Page 471
21.7.2 Loss of volatile flavor components......Page 474
22.1 Introduction......Page 476
22.2.2 Humidity......Page 478
22.2.4 Adiabatic saturation, wet-bulb temperature......Page 479
22.2.5 Dew point......Page 480
22.3.1 The drying curve......Page 481
22.3.2 The constant rate phase......Page 484
22.3.3 The falling rate phase......Page 487
22.3.4 Calculation of drying time......Page 489
22.3.5 Effect of external conditions on the drying rate......Page 492
22.3.6 Relationship between film coefficients in convective drying......Page 493
22.3.8 Characteristic drying curves......Page 494
22.4.1 Batch drying on trays......Page 495
22.4.2 Through-flow batch drying in a fixed bed......Page 497
22.5.1 Basic principles......Page 498
22.5.2 Kinetics......Page 499
22.5.3 Systems and applications......Page 500
22.6 Dryers in the food processing industry......Page 502
22.6.1 Cabinet dryers......Page 503
22.6.2 Tunnel dryers......Page 504
22.6.4 Belt-trough dryers......Page 506
22.6.6 Bin dryers......Page 507
22.6.8 Spray dryers......Page 509
22.6.9 Fluidized bed dryer......Page 514
22.6.10 Pneumatic dryer......Page 515
22.6.11 Drum dryers......Page 516
22.6.12 Screw conveyor and mixer dryers......Page 517
22.7.1 Pre-drying treatments......Page 518
22.7.2 Effect of drying conditions on quality......Page 519
22.7.4 Rehydration characteristics......Page 520
22.8 Energy consumption in drying......Page 521
22.9 Osmotic dehydration......Page 524
23.2 Sublimation of water......Page 528
23.3 Heat and mass transfer in freeze drying......Page 529
23.4.3 Freeze drying, commercial facilities......Page 535
23.4.4 Freeze dryers......Page 536
23.5.1 Basic principles......Page 537
23.5.2 The process of freeze concentration......Page 538
24.2.1 Types of frying......Page 542
24.2.2 Heat and mass transfer in frying......Page 543
24.2.3 Systems and operation......Page 544
24.3 Baking and roasting......Page 545
25.1.2 Ionizing radiations......Page 550
25.1.3 Radiation sources......Page 551
25.1.4 Interaction with matter......Page 552
25.1.5 Radiation dose......Page 554
25.1.6 Chemical and biological effects of ionizing irradiation......Page 555
25.1.7 Industrial applications......Page 557
25.2 High hydrostatic pressure preservation......Page 558
25.4 Pulsed intense light......Page 559
26.1 Introduction......Page 562
26.2.1 Introduction......Page 563
26.2.2 Materials for packaging foods......Page 565
26.2.3 Transport properties of packaging materials......Page 568
26.2.4 Optical properties......Page 570
26.2.5 Mechanical properties......Page 571
26.2.6 Chemical reactivity......Page 572
26.3.1 Vacuum packaging......Page 573
26.3.4 Active packaging......Page 574
26.4 Environmental issues......Page 575
27.1 Introduction......Page 578
27.2.1 Effect of the contaminant......Page 579
27.2.3 Effect of the cleaning agent......Page 581
27.2.5 Effect of mechanical action (shear)......Page 583
27.3 Kinetics of disinfection......Page 584
27.4 Cleaning of raw materials......Page 585
27.5.2 Cleaning in place (CIP)......Page 587
27.7 Odor abatement......Page 588
Appendix......Page 592
Table A.1 Common conversion factors......Page 593
Table A.2 Typical composition of selected foods......Page 594
Table A.4 Thermal properties of materials......Page 595
Table A.6 US standard sieves......Page 596
Table A.7 Properties of saturated steam – temperature table......Page 597
Table A.9 Properties of superheated steam......Page 598
Table A.10 Vapor pressure of liquid water and ice below 0°C......Page 599
Table A.12 Vapor–liquid equilibrium data for ethanol–water mixtures at 1 atm......Page 600
Table A.15 Thermodynamic properties of saturated R-134a......Page 601
Table A.16 Thermodynamic properties of superheated R-134a......Page 602
Table A.17 Properties of air at atmospheric pressure......Page 603
Figure A.2 Psychrometric chart......Page 604
Figure A.4 Mixing power function, propeller impellers......Page 605
Figure A.6 Unsteady state heat transfer in an infinite cylinder......Page 606
Figure A.8 Unsteady state mass transfer, average concentration......Page 607
Figure A.9 Error function......Page 608
C......Page 610
D......Page 611
F......Page 612
G......Page 613
M......Page 614
P......Page 615
R......Page 616
T......Page 617
Y......Page 618
Series List......Page 620