Spray-Freeze-Drying of Foods and Bioproducts: Theory, Applications and Perspectives

Cover
Half Title
Title Page
Copyright Page
Contents
Preface
Acknowledgements
About the Author
Chapter 1. The Inception, Evolution and Theory of Spray-freeze-drying
1.1 The advent of spray-freeze-drying
1.2 Phase diagram of water
1.3 Evolution of the spray-freeze-drying process
1.4 Process and equipment of spray-freeze-drying: An overview
1.5 Advantages of spray-freeze-drying over spray-drying and freeze-drying
1.5.1 Short drying time
1.5.2 Homogeneous and reproducible particle size distribution
1.5.3 Superior flow characteristics
1.5.4 Instant reconstitution properties
1.5.5 Oxidative stability
1.6 Applications of spray-freeze-drying in food and bioproducts processing: An overview
Conclusions
References
Chapter 2. Understanding the Nuances of Spray-freezing Process
2.1 The mechanism and classification of spray-freezing
2.2 Classification of atomizers used in spray-freezing
2.2.1 One-fluid or hydraulic nozzle
2.2.2 Two-fluid nozzle atomizer
2.2.3 Ultrasonic atomizer
2.2.4 Monodisperse droplet generator
2.3 Parameters of atomization
2.4 Freezing of sprayed droplets: Principle and classification
2.4.1 Classification of freezing operation during spray-freeze-drying
2.4.1.1 Spray-freezing into vapor (SFV)
2.4.1.2 Spray-freezing into vapor over liquid (SFV/L)
2.4.1.3 Spray-freezing into liquid (SFL)
2.5 Guidelines for designing a spray-freezing chamber
2.6 Characterization of spray-freezing parameters
2.6.1 Measurement of droplet characteristics (axial velocity, size distribution)
2.6.2 Measurement of gas temperature during spray-freezing
Conclusions
References
Chapter 3. Freeze-drying
3.1 Vacuum spray-freeze-drying
3.1.1 Critical temperatures
3.1.1.1 Methods to determine the critical temperature of formulations and pressure to be set during the primary drying phase
3.1.1.1.1 Differential Scanning Calorimetry (DSC)
3.1.1.1.2 Freeze-drying Microscopy (FDM)
3.1.2 Construction and operation of a vacuum spray-freeze-drying apparatus
3.1.3 Applications, advantages, and limitations of vacuum spray-freeze-drying
3.2 Atmospheric spray-freeze-drying (ASFD) & atmospheric fluidized bed spray-freeze-drying (AFBSFD)
3.2.1 Theory of atmospheric freeze-drying (AFD)
3.2.1.1 Advent and theory of atmospheric spray-freeze-drying (ASFD)
3.2.1.2 Advent and theory of atmospheric fluidized bed spray-freeze-drying (AFBSFD)
3.2.2 Construction and operation of an atmospheric spray-freeze-dryer and atmospheric spray-fluidized-bed freeze-dryer
3.2.3 Applications and advantages of ASFD and ASFBFD
3.2.4 Limitations of ASFD and ASFBFD
3.3 Vacuum fluidized bed spray-freeze-drying (VFBSFD)
3.3.1 Theory
3.3.2 Construction and operation of a vacuum spray-fluidized-bed freeze-dryer
3.3.3 Applications and advantages of VFBSFD
Conclusions
References
Chapter 4. Morphology of Spray-Freeze-Dried Products
4.1 Imaging the morphology of spray-freeze-dried particles
4.2 Morphological patterns of spray-freeze-dried particles
4.2.1 Spherical particles with porous surface morphology
4.2.2 Spherical particles with smooth surface morphology enclosing a porous internal microstructure
4.2.3 Irregular-shaped, wrinkled surface morphology
4.3 Factors influencing the morphology of spray-freeze-dried particles
4.3.1 Feed solid content
4.3.2 Feed composition
4.3.3 Conditions of spray-freezing
4.3.4 Temperature of freeze-drying
Conclusions
References
Chapter 5. Spray-freeze-drying of dairy products
5.1 Spray-freeze-drying of whole milk
5.1.1 Microstructure of spray-freeze-dried whole milk powder
5.1.2 Particle size of spray-freeze-dried whole milk powder
5.1.3 Wettability of spray-freeze-dried whole milk powder
5.2 Spray-freeze-drying of skim milk
5.2.1 Morphology of spray-freeze-dried skim milk powder
5.2.2 Particle size of spray-freeze-dried skim milk powder
5.2.3 Wettability of spray-freeze-dried skim milk powder
5.3 Spray-freeze-drying of whey protein
5.3.1 Physical properties of spray-freeze-dried whey protein powder
5.3.2 Morphology of spray-freeze-dried whey protein powder
5.3.3 Solubility of spray-freeze-dried whey protein powder
Conclusions
References
Chapter 6. Spray-freeze-drying for soluble coffee production
6.1 Process flow for soluble coffee production by spray-freeze-drying
6.1.1 Stage-1: Atomization
6.1.2 Stage-2: Freezing
6.1.2.1 Microstructure of spray-frozen coffee droplets
6.1.3 Stage-3: Freeze-drying
6.2 Quality characteristics of spray-freeze-dried soluble coffee - An overview
6.2.1 Physical characteristics
6.2.1.1 Moisture content
6.2.1.2 Particle size and shape
6.2.1.3 Solubility
6.2.1.4 Bulk density and tapped density
6.2.1.5 Flowability
6.2.1.6 Color
6.2.2 Aroma quality of spray-freeze-dried soluble coffee
6.2.2.1 Qualitative analysis of aroma quality by electronic nose
6.2.2.2 Quantitative profiling of aromatic volatiles in spray-freeze-dried soluble coffee by gas chromatography-mass spectroscopy (GC-MS)
6.2.2.3 Mechanism of volatile retention during spray-freeze-drying
6.3 Merits of spray-freeze-drying as a soluble coffee production process
Conclusions
References
Chapter 7. Spray-freeze-drying for the Encapsulation of Food Ingredients and Biologicals
7.1 A prelude to encapsulation
7.1.1 Classification of encapsulation techniques
7.2 Principle of encapsulation by spray-freeze-drying
7.3 Factors influencing encapsulation by spray-freeze-drying
7.4 Selection of wall materials for encapsulation by spray-freeze-drying
7.4.1 Solubility
7.4.2 Emulsifiability
7.4.3 Film-forming ability
7.4.4 Viscosity
7.5 Pertinent case-studies on encapsulation by spray-freeze-drying
7.5.1 Encapsulation of food ingredients
7.5.1.1 Docosahexaenoic acid
7.5.1.2 Vanillin
7.5.1.3 Vitamin E
7.5.1.4 Bromelain
7.5.1.5 Probiotics
7.5.2 Biologicals encapsulated by spray-freeze-drying
7.5.2.1 Bovine serum albumin
7.5.2.2 Immunoglobulin G (IgG)
Conclusions
References
Web references
Chapter 8. Spray-freeze-dried Particles as Novel Delivery Systems for Vaccines and Active Pharmaceutical Ingredients
8.1 Rationale and applications of spray-freeze-drying for the development of pulmonary delivery systems
8.1.1 Pulmonary delivery system - A prelude
8.1.2 Quantifying the performance of aerosolized dry powder particles: Cascade impactor analysis
8.1.3 Spray-freeze-dried particles for pulmonary delivery: Pertinent case-studies
8.1.3.1 Vaccine powders
8.1.3.2 Antibiotics
8.1.3.3 Proteins
8.1.3.4 Drugs and APIs
8.1.3.5 Therapeutic genes and nucleic acids
8.2 Rationale and applications of spray-freeze-drying for the development of transdermal delivery systems
8.2.1 Transdermal delivery systems - A prelude
8.2.1.1 Stages in transdermal delivery
8.2.2 Preparation of dry powders for transdermal delivery by spray-freeze-drying
Conclusions
References
Chapter 9. Spray-freeze-drying for the Production of Therapeutic Nanoparticles
9.1 Spray-freeze-drying as the technique for nanoparticle production
9.2 Customization of SFD process for nanoparticle production
9.2.1 Use of freezing adjuvants in the feed formulation
9.2.2 Atomization: The use of ultrasonic nozzles and spray gun
9.2.3 Freezing
9.3 Nanoparticles produced using spray-freeze-drying
9.3.1 Spray-freeze-drying for the production of nanoparticle aggregates for inhaled drug delivery
9.3.2 Spray-freeze-drying as an approach for the improved dissolution and oral bioavailability of poorly water-soluble drugs
Conclusions
References
Chapter 10. Properties of Spray-freeze-dried Products and their Characterization
10.1 Characterization of spray-freeze-dried pharmaceutical proteins
10.1.1 Protein stability and integrity
10.1.1.1 Size exclusion chromatography
10.1.1.2 Reverse phase high performance liquid chromatography (RP-HPLC)
10.1.1.3 Gel electrophoresis
10.1.1.4 Ultraviolet spectroscopy
10.1.2 Secondary and tertiary structure of proteins
10.1.2.1 Fourier-transform infrared (FTIR) spectroscopy
10.1.2.2 Circular dichroism spectroscopy
10.1.2.3 Fluorescence spectroscopy
10.2 Characterization of dry powders for pulmonary and needle-free ballistic delivery
10.2.1 Hygroscopicity
10.2.2 Bulk density
10.3 Characterization of spray-freeze-dried drugs/API
10.3.1 Dissolution property
10.3.2 Specific surface area and porosity
10.3.2.1 Surface area
10.3.2.1.1 Theory and instrumentation of BET surface area determination
10.3.2.2 Porosity
10.3.3 Drug amorphism and crystallinity
10.3.3.1 XRD as a tool to determine the crystallinity of SFD powders
10.3.3.2 DSC as a tool to obtain structural information of SFD powders
10.4 Characterization of food powders and encapsulated food bioactives
10.4.1 Moisture content
10.4.2 Flowability
10.4.3 Encapsulation efficiency
10.4.4 Chemical interaction between constituents
10.4.5 Oxidative and thermal stability
10.4.6 Release kinetics of encapsulated bioactives
Conclusions
References
Chapter 11. Computational Fluid Dynamics Modeling of Spray-freeze-drying Process
11.1 Theory of CFD modeling
11.2 Steps in the CFD modeling
11.3 Numerical simulations of gas-particle interactions
11.4 Discretization
11.4.1 Finite element method (FEM)
11.4.2 Finite volume method (FVM)
11.4.3 Finite difference method (FDM)
11.5 Reference frames in CFD modeling
11.5.1 Volume of fluid (VOF)
11.5.2 Eulerian-Eulerian (E-E)
11.5.3 Eulerian-Lagrangian (E-L)
11.5.4 Turbulence models
11.6 Case-study: CFD modeling to predict the influence of spray-freezing chamber design and spray patterns on particle characteristics
11.6.1 Step-1: Pre-processing
11.6.1.1 Definition of the problem
11.6.1.2 Geometry creation
11.6.1.3 Meshing
11.6.2 Solving
11.6.2.1 Boundary conditions
11.6.3 Post-processing: Simulation results and experimental validation
11.6.3.1 Simulation without spray injection
11.6.3.2 Simulation with spray injection
11.6.3.2.1 Case A: Solid (or) full cone spray
11.6.3.2.1.1 Axial velocity and temperature of gas
11.6.3.2.1.2 Particle histories (Velocity, temperature, and residence time distributions)
11.6.3.2.2 Case B: Hollow cone spray
11.6.3.2.2.1 Gas axial velocity and temperature
11.6.3.2.2.2 Particle axial velocity
11.6.3.2.2.3 Particle temperature
11.6.3.2.2.4 Particle impact position
11.6.3.2.3 Case C: Modified spray-freezing chamber design
11.6.3.2.3.1 Axial velocity and temperature of gas
11.6.3.2.3.2 Particle axial velocity and temperature
11.6.3.2.3.3 Particle impact position
Conclusions
References
Chapter 12. Spray-freeze-drying: Challenges and Solutions in the Way Forward
12.1 Identifying the bottlenecks of spray-freeze-drying process
12.1.1 Resource-related bottlenecks
12.1.2 Process-related bottlenecks and relevant solutions
12.1.2.1 Challenges imposed by the spray-freezing step
12.1.2.2 Challenges associated with the freeze-drying stage and proposed solutions
12.2 Continuous spray-freeze-drying process: A solution in the way forward
12.2.1 Prototypes of continuous SFD systems
12.2.1.1 Rey's model
12.2.1.2 Spray-freezing followed by dynamic freeze-drying
12.2.1.3 Fine-spray freeze-drying
12.2.1.4 Stirred freeze-drying or active freeze drying
12.2.1.5 Improved Rey's system for continuous processing of spray-freeze-dried products
Conclusions
References
Index