Introduction to Food Engineering

Home Syllabus
Material Balances Energy Balances
Fluids Laminar and Turbulent Flow Volumetric Flow and Friction Bernoulli's Equation and Pump Power Flow Measurement
Thermodynamic Properties
Modes of heat transfer Conduction in walls Conduction in multilayered walls Convection heat transfer Forced Convection Free Convection Overall Heat Transfer Coefficient Heat Exchangers Unsteady State Heat Transfer Heisler Charts
Decimal Reduction Time F value General Method Improved General Method
Properties of Air and Water Vapor Psychrometric Chart
Moisture Content and Drying Rates Drying Time
Single Effect Evaporator Multiple Effect and Industrial Evaporators
Refrigerants Vapor Compression Refrigeration System Ideal and Non-Ideal Cycle
Ice Crystallization Freezing Time Freezer Selection
Instructions List of Experiments

Food Dehydration - Drying Time, Food Dehydration Systems

Learning Outcomes

At the end of this module, you will be able to:

  1. predict drying time during constant rate drying period
  2. predict drying time during falling rate period
  3. describe different types of food dehydration systems

When foods with high moisture content are dried, they often exhibit a constant-rate period before the falling-rate period. In this module, we will obtain mathematical equations to estimate the drying time for these two rate periods. We will also view different types of dehydration systems used in the food industry. In the following video, we will consider the constant rate period and develop equations to predict drying time.

The constant-rate drying period precedes the falling-rate period. For some food products with low initial moisture content, the constant-rate drying period is absent; we observe only the falling rate period. In the next video, we will consider the mathematical development of an equation to predict drying time for a falling rate period

There are numerous types of dryers used in the food industry. In the next video, you will view animations of some of the more common types of dryers.

Recap

In this module, you learned how to obtain mathematical equations to estimate drying times for constant-rate and falling-rate periods. You also viewed different types of drying systems used in the food industry.