Food Engineering II - Dehydration

What is the most widely used type of food dryer?

• Solar air dryer

• Hot air dryer

• Rotary dryer

• Tunnel dryer

Which drying method is best suited for fruits with high sugar and acid content?

• Hot air drying

• Solar drying

• Spray drying

• Freeze drying

Which type of dryer is used for drying seeds, corn gluten, distiller's grains, and some fruit?

• Hot air dryer

• Rotary cascade dryer

• Tunnel dryer

• Single-belt conveyor dryer

Which drying method is commonly used for skim milk, liquid eggs, instant coffee and tea, whey proteins, and enzymes?

• Hot air drying

• Spray drying

• Freeze drying

• Osmotic drying

Which drying method is used for higher value foods like instant coffee, backpacking foods, space foods, and select ingredients?

• Hot air drying

• Spray drying

• Freeze drying

• Osmotic drying

What is the purpose of a vacuum dryer in the drying process?

• To reduce the boiling point of water

• To increase the temperature difference between product and surroundings

• To create a reduced oxygen environment

• To enhance mass transfer of water out of the food

Which drying method is used for converting liquid food items into powders and small, dry particles?

• Hot air drying

• Spray drying

• Freeze drying

• Osmotic drying

What is the main advantage of freeze drying compared to hot air drying?

• Faster drying time

• Higher thermal efficiency

• Less impact on flavor, color, and nutrients

• Lower equipment costs

Which factor does NOT affect the rate of drying?

• Shape of the material

• Initial moisture content

• Dryer design

• Seasonal variation in material

What is the recommended air temperature for hot air dryers?

• Below 40°C

• 40°C to 80°C

• 80°C to 100°C

• Above 100°C