Development of Packaging and Products for Use in Microwave Ovens (Woodhead Publishing in Materials)

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Development of Packaging and Products for Use in Microwave Ovens
Copyright
Contributors
Introduction
Part One: Principles
1 - Electromagnetic basis of microwave heating
	1.1 Introduction
	1.2 Microwaves
	1.3 Electromagnetic fields
		1.3.1 Field vectors
		1.3.2 The wave equation
		1.3.3 Plane waves
		1.3.4 Polarization
	1.4 Constitutive parameters εε0,μμ0,and σ
		1.4.1 Dielectric media
		1.4.2 Dielectric properties of foods
	1.5 Power
		1.5.1 Poynting vector
		1.5.2 Power dissipation
		1.5.3 Power penetration depth
	1.6 Wave interference (standing and traveling waves)
	1.7 Reflection and transmission of plane waves at an interface
		1.7.1 Transverse magnetic polarization
		1.7.2 Transverse electric polarization
		1.7.3 Comments on the Fresnel coefficients
	1.8 Propagation in lossy material of finite thickness
	1.9 Rectangular waveguide
		1.9.1 Transverse electric fields in waveguide
		1.9.2 Transverse magnetic fields in waveguide
		1.9.3 TE10 mode in rectangular waveguide
	1.10 Resonant cavities
	1.11 Summary
	1.12 Further reading
	Appendix A Some mathematics for electromagnetics
	A.1 Complex numbers
	A.2 Sinusoidal steady state—phasors
	A.3 Vectors
	A.4 Maxwell's equations
	A.5 Wave equations
	References
2 - Influence of food geometry and dielectric properties on heating performance
	2.1 Introduction
	2.2 Microwave heating performance and uniformity
		2.2.1 Materials: influence of dielectric and thermal properties
		2.2.2 Heating foods in microwave ovens: food dielectric properties, geometry, and ovens
			2.2.2.1 Runaway heating
		2.2.3 Concentrated heating effects and the influence of food geometry
			2.2.3.1 Edge overheating
			2.2.3.2 Corner overheating
			2.2.3.3 Center overheating in spheroidal and cylindrical loads
			2.2.3.4 Standing waves in large, flat loads
			2.2.3.5 Interacting heating effects
			2.2.3.6 Ready meals
	2.3 Methodologies to control microwave heating performance
		2.3.1 Prediction, improvement, and validation of microwave heating performance
	References
3 - Advanced topics in heating uniformity—theory and experimental methods
	3.1 Introduction—microwave heating and the microwave generator developments
	3.2 Introduction—the operating microwave frequency choices, reasons, and consequences
	3.3 Introduction—microwave ovens
		3.3.1 From the beginning until about 1970
		3.3.2 Developments from the early 1970s to 2018
	3.4 Plane wave reflection at a flat dielectric surface: Brewster conditions
	3.5 Cavity modes
		3.5.1 Introduction
		3.5.2 Waveguide and cavity modes
		3.5.3 Analytical analysis of cavity fields and their load interactions
			3.5.3.1 Mode and load impedances
			3.5.3.2 A 2450MHz small cavity example
			3.5.3.3 A 2450MHz larger cavity example
			3.5.3.4 The horizontal heating patterns by volume modes in a large flat load
			3.5.3.5 Some conclusions from Section 3.5.3
		3.5.4 Multimode cavities
			3.5.4.1 Historical background
			3.5.4.2 Later historical developments
			3.5.4.3 A detailed multimode example
			3.5.4.4 Discussion and summary
	3.6 Underheating modes
	3.7 Numerical modeling of a small oven cavity
		3.7.1 Cavity dimensions and load data
		3.7.2 Feed slot impedance matching
		3.7.3 Field studies
		3.7.4 Descriptions and analysis of a “MICROWAVE MOVIE”
	3.8 Different kinds of uneven heating depending on the loads
		3.8.1 General and outline
		3.8.2 The microwave penetration depth
		3.8.3 Internal vertical standing waves in large flat loads
		3.8.4 Influences by different ε″, with the same ε′
		3.8.5 Simultaneous heating of contacting load parts with different ε′
		3.8.6 The edge overheating effect
		3.8.7 Heating of isolated spherical objects
			3.8.7.1 Introduction
			3.8.7.2 Small spheres
			3.8.7.3 The exploding egg effect
		3.8.8 Other effects in single loads
			3.8.8.1 The cold rim effect
			3.8.8.2 The hot corner effect
			3.8.8.3 Particular heating effects in small-scale uneven top surfaces
			3.8.8.4 The burnt stripe effect
		3.8.9 Rounded load item proximity effects
			3.8.9.1 The three kinds of effects
			3.8.9.2 Smaller objects than for the spherical TE101 resonance
			3.8.9.3 In the region of the external spherical TM101 mode field
		3.8.10 Combination effects
			3.8.10.1 Combination of the cold rim and exploding egg effects
			3.8.10.2 Adjacent or compartmented food containers
			3.8.10.3 Some heating pattern characteristics of a multicomponent food load
	3.9 Two microwave oven performance test methods
		3.9.1 A method for determination of the effective equivalent θi in microwave ovens
			3.9.1.1 General
			3.9.1.2 Gel composition and preparation
			3.9.1.3 Procedure
			3.9.1.4 Calculations
		3.9.2 The IEC batter heating test
			3.9.2.1 General
			3.9.2.2 Preparations
			3.9.2.3 Procedure
			3.9.2.4 Analysis, grading, and some actual results
			3.9.2.5 Dielectric and thermal data for modeling and extended experiments
		3.9.3 On the choice of microwave ovens for test programs in the food industry
	References
4 - Microwave ovens
	4.1 Introduction
	4.2 History of the microwave oven
	4.3 Oven design and construction
	4.4 Influence of oven design and metal packaging on heating performance
		4.4.1 Mode stirrers
		4.4.2 Influence of metal on heating uniformity
			4.4.2.1 Arcing
		4.4.3 Other influences on nonuniform heating
		4.4.4 Aging of microwave ovens
	4.5 Combination ovens
		4.5.1 Speed ovens
	4.6 Microwave oven safety
	4.7 Sources of further information and advice
	References
5 - Measurements of dielectric properties of foods and associated materials
	5.1 Introduction
	5.2 Historical developments and chapter outline
	5.3 Absolute and analytical methods for enclosed MUTs
		5.3.1 The filled waveguide or coaxial line nonresonant method
		5.3.2 End-filled waveguide and coaxial line resonant methods
		5.3.3 Resonance perturbation methods
	5.4 Absolute and analytical methods for infinite MUTs
		5.4.1 The contacting open-ended coaxial line method
			5.4.1.1 General
			5.4.1.2 The issues with MUT inhomogeneities
			5.4.1.3 A detailed example of a layered MUT by probe mechanical pressure
			5.4.1.4 Some conclusions
		5.4.2 The trapped surface wave method
	5.5 A calibration method for food samples in closed glass tubes
		5.5.1 Introduction
		5.5.2 The circular TM012 cavity
	5.6 Retromodeling techniques
		5.6.1 Introduction
		5.6.2 A dual resonant frequency method
			5.6.2.1 General
			5.6.2.2 The retromodeling
			5.6.2.3 Sources of error: accuracy
		5.6.3 A degenerate resonance method for large MUTs
		5.6.4 A commercially available resonant applicator system for food MUTs
	5.7 Summary and conclusions
	References
6 - Microwave dielectric properties of foods and some other substances
	6.1 Introduction
	6.2 Information on the microwave absorption mechanisms in water and foods
		6.2.1 General
		6.2.2 The dipole relaxation phenomenon
		6.2.3 Ionic absorption
	6.3 Microwave dielectric data of water
		6.3.1 Static (zero frequency) permittivity data of water
		6.3.2 Relaxation frequency data of water
		6.3.3 Water data at 915 and 2450MHz
		6.3.4 The power penetration depth of liquid water
	6.4 Contributions by ions
	6.5 Data of water and some other liquids at 2450MHz
		6.5.1 Pure water and alcohols
		6.5.2 Sugar solutions
	6.6 Data for some food substances with high water content
	6.7 Data for some food substances with low water content
	6.8 Data for numerical modeling
	6.9 Mixture formulas and two examples of use
		6.9.1 Two mixture formulas
		6.9.2 An example of frozen meat
		6.9.3 An example of saturated sugar solution and sugar crystals
		6.9.4 Conclusions
	6.10 Large particulate foods and limitations of the mixture equations
	References
Part Two: Microwave packaging materials and design
7 - Passive microwave packaging forms
	7.1 Introduction
	7.2 Conditions of use
		7.2.1 Conventional, microwave only, or dual-ovenable
		7.2.2 Distribution: frozen/chilled/shelf-stable
	7.3 Operations
		7.3.1 Manual/semiautomated/automated
		7.3.2 Film sealed/flow-wrapped/nonsealed
	7.4 Application drives material selection and material selection drives design
		7.4.1 Rigid plastic containers
		7.4.2 Flexible packaging
		7.4.3 Paperboard-based containers
			7.4.3.1 Pressed paperboard containers
			7.4.3.2 Molded fiber containers
			7.4.3.3 Environmentally friendly coatings
		7.4.4 Design considerations
	7.5 Product steaming
	7.6 Tray geometry
		7.6.1 Rounds, ovals, and rectangles
		7.6.2 Elevation
		7.6.3 Two-piece
	7.7 Conclusions
8 - Susceptors in microwave packaging
	8.1 Introduction
	8.2 History
	8.3 Reflection, transmission, and absorption of microwave power by a susceptor
	8.4 Temperature limiting in PET susceptors
	8.5 Measurement methods
	8.6 Manufacture
		8.6.1 Manufacture: overview
		8.6.2 Manufacture: applying the resistive active coating
			8.6.2.1 Evaporation deposition
			8.6.2.2 Sputter deposition
			8.6.2.3 Electron beam
			8.6.2.4 Chemical vapor deposition
		8.6.3 Manufacture: applying the coated substrate to the supporting structure
		8.6.4 Manufacture: susceptors in disposable packaging
	8.7 Use and application
		8.7.1 Use and application: oven considerations
		8.7.2 Use and application: overview of design considerations
		8.7.3 Use and application: the heating dynamic
		8.7.4 Use and application: geometry effects
		8.7.5 Use and application: alternatives to the PET susceptor
	8.8 Conclusions
	References
9 - Shielding and field modification of thick metal films
	9.1 Introduction
	9.2 History
		9.2.1 Objectives of use
		9.2.2 Introduction to shielding and field modification
		9.2.3 Early thick metal approaches
		9.2.4 Commercializing thick metal packages
	9.3 Physics and design principles
		9.3.1 How thick is a thick metal film?
		9.3.2 The roles of thick metal films in microwave packaging
			9.3.2.1 Even heating
			9.3.2.2 Detuning unloaded resonant elements
			9.3.2.3 Controlled differential heating
			9.3.2.4 Browning and crisping
	9.4 Patterning thick metal films
		9.4.1 Patterning approaches explored
		9.4.2 Chemical etching
		9.4.3 IML shielding
		9.4.4 Designing thick metal film patterns
	9.5 Antennas
	9.6 Application examples
	9.7 Conclusions and outlook
	9.8 Sources of further information and advice
	References
Part Three: Product development, food, packaging, and oven safety
10 - Flavors and colors for microwave foods
	10.1 Introduction
	10.2 What are flavors?
	10.3 Natural versus artificial flavors
	10.4 Sources of flavoring materials
	10.5 Flavor creation
	10.6 Microwave versus conventional heating
	10.7 Flavor forms
	10.8 Browning reaction
		10.8.1 Enzymatic browning
		10.8.2 Caramelization
		10.8.3 Maillard browning
		10.8.4 Solutions
	10.9 Product categories and challenges
		10.9.1 High-moisture foods
		10.9.2 Breads and cakes
		10.9.3 Other baked foods
		10.9.4 Fried foods
		10.9.5 Microwave popcorn
		10.9.6 Beverages
	10.10 Conclusions
	References
11 -  Addressing product performance issues through ingredients
	11.1 Introduction
	11.2 Bread toughening
		11.2.1 Phenomena
		11.2.2 Mechanisms
			11.2.2.1 Thermal setting of gluten
			11.2.2.2 Recrystallization of amylose
		11.2.3 Solutions
	11.3 Meat toughening
		11.3.1 Phenomena
		11.3.2 Mechanisms
			11.3.2.1 Cooking loss
			11.3.2.2 Structural change in meat fibers due to superheated steam
			11.3.2.3 Matrix densification due to superheated steam
			11.3.2.4 Heating conditions
			11.3.2.5 Possible nonthermal effect
		11.3.3 Solutions
			11.3.3.1 Tenderization treatments
			11.3.3.2 Using endo-genous or added fat as a tenderizer
			11.3.3.3 Adding protease to break down muscle structure
			11.3.3.4 Adding and/or retaining more moisture in the heated meat matrix
	11.4 Pasta softening
		11.4.1 Phenomena
		11.4.2 Mechanisms
			11.4.2.1 More complete gelatinization
			11.4.2.2 More rapid heating
		11.4.3 Solutions
			11.4.3.1 Minimizing the initial moisture content of pasta during manufacturing
			11.4.3.2 Developing a new, alternative hydrocolloid network
			11.4.3.3 Conditioning the durum wheat
			11.4.3.4 Pre-parboiling the pasta
			11.4.3.5 Using eggs and triethyl citrate
			11.4.3.6 Coating the pasta surface with a mixture of dried coagulated egg white and edible oil
	11.5 Microwave bumping
		11.5.1 Phenomena
		11.5.2 Mechanism
		11.5.3 Solutions
	11.6 Microwave runaway heating
		11.6.1 Phenomena
		11.6.2 Mechanism
		11.6.3 Solutions
	11.7 Conclusions
	References
12 - Package and product development testing in a microwave oven
	12.1 Introduction
	12.2 Realities of heating food in microwave ovens
	12.3 Consumer microwave oven variability
	12.4 Commercial microwave oven variability
	12.5 Consumer variability
	12.6 Product variability
	12.7 Measurable responses
	12.8 Basic experimentation in microwave ovens
	References
13 - Principles of sensory science and consumer research for microwaveable products
	13.1 Introduction
	13.2 Sensory perception and types of responses
	13.3 Impact of microwave heating on sensory properties
	13.4 Factors influencing preparation of microwaveable samples for sensory evaluation
	13.5 Sensory assessment of microwaveable foods
	13.6 Example of the synergy between sensory and consumer research
	References
14 - Validation of microwave cooking directions
	14.1 Room setup
	14.2 Electrical voltage
	14.3 Brands, size, and wattages
	14.4 Output testing
	14.5 Number of replications for testing
	14.6 Testing simplified
	14.7 Performing the validation
	14.8 Product weights
	14.9 Temperature measurement
	14.10 Infrared thermography
	14.11 Product storage
	14.12 Data to record
		14.12.1 Required data
		14.12.2 Other data
	14.13 Other cooking methods
	14.14 Conclusion
15 - The impact of solid-state RF technology on product development
	15.1 Introduction
	15.2 Solid-state RF generator subsystem
		15.2.1 Partitioning
	15.3 RF amplifier terminology and parameters
		15.3.1 Multichannel RF system considerations
		15.3.2 Designing for solid-state RF augmented appliances
	15.4 Designing recipes—the software
		15.4.1 The right amount of energy
		15.4.2 Homogeneous RF energy distribution
		15.4.3 Inhomogeneous energy distribution application
		15.4.4 We will not beat physics
		15.4.5 Other heat sources
	15.5 Conclusions
	References
16 - Regulatory concerns regarding microwave packaging
	16.1 Introduction
	16.2 History of microwave package regulations
	16.3 Current regulations
	References
17 - Microwave oven safety
	17.1 Microwave safety basics
	17.2 Microwave ovens and pacemakers
	17.3 Electromagnetic field exposure—industrial applications
	Appendix: Microwave oven survey meters
Part Four: Modelling of microwave heating
18 - Modeling of cavities and loads with FDTD and FEM methods
	18.1 Introduction
	18.2 Finite differences time domain versus finite elements method
		18.2.1 The finite difference time domain method
			18.2.1.1 Lossy and dispersive media
			18.2.1.2 Numerical error bounds
			18.2.1.3 Conformal meshing and material boundary modeling
		18.2.2 Finite element method
			18.2.2.1 FEM error bounds
	18.3 Electromagnetic-thermodynamic simulation: unilateral and bilateral coupling
	18.4 Computational examples
		18.4.1 Wide-band modeling of a microwave oven
		18.4.2 Coupled EM-thermal modeling of microwave heating process
	18.5 Conclusions
	Acknowledgments
	References
19 - Space-discrete electromagnetic modeling of microwave susceptors
	19.1 Introduction
	19.2 Macroscopic model of susceptor for electromagnetic modeling
	19.3 Accuracy of the macroscopic model—sensitivity to thickness of equivalent layer
	19.4 Sensitivity of susceptor model to angle of incidence and wave polarization
	19.5 Changes in characteristic impedance and their influence on model behavior
	19.6 Introducing an anisotropy to the macroscopic model of a susceptor
	19.7 Application of the macroscopic model of susceptors to real-life simulation scenario
	19.8 Summary
	References
20 - Modeling of excitation in domestic microwave ovens
	20.1 Introduction
	20.2 Magnetron feeds and their spectra
	20.3 Time-domain modeling of a typical magnetron excitation
	20.4 Time-domain modeling regimes dedicated to solid-state sources analysis
	20.5 Relevance of modeling regimes to device development
	20.6 Conclusions
	Acknowledgments
	References
Index
	A
	B
	C
	D
	E
	F
	G
	H
	I
	J
	K
	L
	M
	N
	O
	Q
	R
	S
	T
	U
	V
	W
	X
	Y
	Z
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