Post-Harvest Technology and Processing

6.

Drying and Dehydration Technology

6.1.

Fundamental Principles of Drying

6.1.1.

Moisture Content Concepts

6.1.1.1.

Wet Basis and Dry Basis Calculations

6.1.1.2.

Equilibrium Moisture Content

6.1.1.3.

Critical Moisture Content

6.1.2.

Water Activity Relationships

6.1.2.1.

Water Activity Definition and Measurement

6.1.2.2.

Relationship to Microbial Growth

6.1.2.3.

Sorption Isotherms

6.1.2.4.

Stability Considerations

6.1.3.

Heat and Mass Transfer

6.1.3.1.

Drying Mechanisms

6.1.3.2.

Heat Transfer Modes

6.1.3.3.

Mass Transfer Principles

6.1.3.4.

Drying Rate Curves

6.1.4.

Psychrometric Properties

6.1.4.1.

Air-Water Vapor Relationships

6.1.4.2.

Humidity Measurements

6.1.4.3.

Drying Air Conditions

6.2.

Traditional and Solar Drying

6.2.1.

Open Sun Drying

6.2.1.1.

Advantages and Limitations

6.2.1.2.

Product Suitability

6.2.1.3.

Quality Considerations

6.2.2.

Solar Drying Systems

6.2.2.1.

Direct Solar Dryers

6.2.2.2.

Indirect Solar Dryers

6.2.2.3.

Mixed-Mode Solar Dryers

6.2.2.4.

Solar Collector Design

6.2.3.

Natural Air Drying

6.2.3.1.

Ventilation Requirements

6.2.3.2.

Structural Design

6.2.3.3.

Moisture Management

6.3.

Mechanical Drying Systems

6.3.1.

Tray and Cabinet Dryers

6.3.1.1.

Design and Construction

6.3.1.2.

Air Circulation Systems

6.3.1.3.

Temperature Control

6.3.2.

6.3.2.1.

Continuous Operation Principles

6.3.2.2.

Product Handling Systems

6.3.2.3.

Process Control

6.3.3.

6.3.3.1.

Design Features

6.3.3.2.

Heat Transfer Mechanisms

6.3.3.3.

Product Movement Patterns

6.3.4.

Fluidized Bed Dryers

6.3.4.1.

Fluidization Principles

6.3.4.2.

Bed Design Parameters

6.3.4.3.

Heat and Mass Transfer

6.3.5.

Spray Drying Technology

6.3.5.1.

Atomization Methods

6.3.5.2.

6.3.5.3.

Product Recovery Systems

6.3.6.

Drum Drying Systems

6.3.6.1.

Single and Double Drum Designs

6.3.6.2.

Film Formation and Removal

6.3.6.3.

Product Quality Factors

6.4.

Advanced Drying Technologies

6.4.1.

Freeze Drying Processes

6.4.1.1.

Freezing Stage Operations

6.4.1.2.

Primary Drying Phase

6.4.1.3.

Secondary Drying Phase

6.4.1.4.

Equipment Design and Operation

6.4.2.

Vacuum Drying Systems

6.4.2.1.

Vacuum Generation and Control

6.4.2.2.

Heat Transfer Under Vacuum

6.4.2.3.

Product Quality Benefits

6.4.3.

Microwave and Radio Frequency Drying

6.4.3.1.

Heating Mechanisms

6.4.3.2.

Equipment Design

6.4.3.3.

Process Control Challenges

6.4.4.

Osmotic Dehydration

6.4.4.1.

Mass Transfer Principles

6.4.4.2.

Osmotic Solution Management

6.4.4.3.

Combined Drying Processes

6.5.

Quality Control in Drying

6.5.1.

Nutritional Quality Changes

6.5.1.1.

Vitamin and Mineral Losses

6.5.1.2.

Protein and Amino Acid Changes

6.5.1.3.

Antioxidant Retention

6.5.2.

Physical Quality Attributes

6.5.2.1.

Color Changes and Browning

6.5.2.2.

Texture and Rehydration Properties

6.5.2.3.

Shrinkage and Case Hardening

6.5.3.

Sensory Quality Factors

6.5.3.1.

Flavor and Aroma Changes

6.5.3.2.

Appearance and Visual Quality

6.5.3.3.

Mouthfeel and Texture

Previous

5. Preliminary Processing Operations

Go to top

Next

7. Storage Technology and Management